Joseph C. Liao
Kathryn Simmons Stamey Professor
Urology
Web page: http://web.stanford.edu/people/jliao
Bio
Joseph Liao is the Kathryn Simmons Stamey Professor and a professor of urology Stanford University. Dr. Liao is a board-certified urologic surgeon and a physician scientist who is nationally recognized for his contributions in optical imaging and image-guided surgery of urological cancers, and development of urine-based precision diagnostics for bladder cancer and urinary tract infections. Fellowship-trained in endourology and minimally invasive surgery, his clinical practice focuses on care of patients with early-stage high risk urothelial and prostate cancer.
Dr. Liao graduated with honors from Harvard College and earned his medical degree from Stanford School of Medicine. He completed his urology residency and clinical fellowship at UCLA Medical Center and a research fellowship at UCLA School of Engineering. He joined the faculty in the Department of Urology at Stanford in 2006 and currently serves as vice chair for academic affairs, director of research, and co-director of the endourology fellowship. For 15 years, he served as the chief of urology at VA Palo Alto Health Care System. Dr. Liao is a member of Stanford Bio-X, Cancer Institute, Center for Artificial Intelligence in Medicine and Imaging, and Canary Center for Early Cancer Detection.
Dr. Liao’s scholarship focuses on development of precision diagnostics and therapy for major urological diseases including bladder cancer, urinary tract infections, and kidney stone disease. His multidisciplinary laboratory interfaces genomics, imaging science, data science, and clinical medicine. He has served as the principal investigator on several NIH R01’s on molecular imaging, liquid biopsy, and AI-augmented surgery for bladder cancer; as well as development of integrated biosensors for rapid uropathogen identification and antimicrobial susceptibility testing. He has authored over 180 publications in top journals including Science Translational Medicine, Nature Medicine, Cell, Cancer Cell, PNAS, JAMA Surgery, and European Urology, and served as a reviewer on over 30 NIH study sections. Dr. Liao is committed to the training of next generation of physician scientists and researchers and directs the K12 Urology Research (KURe) career development program at Stanford. Many of his over 50 students and trainees are leaders and emerging leaders in academia and industry.
Dr. Liao is an elected member of the American Society of Clinical Investigation. He is active in major national urology organizations and formerly served as the president of the Engineering and Urology Society and member of the board of the directors for the Endourology Society.
Clinical Focus
- Urology
- Urologic Neoplasms
- Minimally Invasive Surgical Procedures
- Urolithiasis
- Urinary Tract Infections
Administrative Appointments
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Program Director, NIH/NIDDK K12 Urology Research at Stanford (KUReS) Career Development Program (2023 - Present)
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National Co-Chair, VA Multi-Cancer Early Detection (MCED) Partnership with NCI Cancer Screening Research Network (CSRN) (2023 - Present)
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Associate Member, Canary Center at Stanford for Early Cancer Detection (2022 - Present)
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Vice Chair for Academic Affairs, Department of Urology, Stanford University (2021 - Present)
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Director of Research, Department of Urology, Stanford University (2017 - Present)
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Standing Member, Assistant Professors Review Committee (APRC), Stanford School of Medicine (2017 - 2023)
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Standing Member, NIH Study Section - Instrumentation and Systems Development (ISD) (2013 - 2017)
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Chief of Urology, VA Palo Alto Health Care System (2006 - 2021)
Honors & Awards
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Elected Member, American Society for Clinical Investigation (2022)
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Scholar, AUA/CUA International Exchange Program (2012)
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First Place, AUA Foundation Young Investigator Research Forum (2009)
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Faculty Fellows Leadership Program, Stanford University School of Medicine (2008)
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Research Scholar, American Foundation for Urologic Disease (2003 - 2005)
Boards, Advisory Committees, Professional Organizations
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Member, New Technologies & Imaging Committee, American Urological Association (2024 - Present)
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Board of Directors, Endourology Society (2022 - 2023)
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President, Engineering and Urology Society (2022 - 2023)
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Programming Committee, SPIE Photonics West - Urology (2017 - Present)
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Diplomate, American Board of Urology (2008 - Present)
Professional Education
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Clinical Fellowship, UCLA Medical Center, Endourology / Minimally Invasive Surgery (2006)
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Research Fellowship, UCLA School of Engineering, Molecular Diagnostics (2005)
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Residency, UCLA Medical Center, Urology (2003)
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Internship, UCLA Medical Center, Surgery (1998)
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MD, Stanford University, Medicine (1997)
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AB, Harvard University, Biology (1993)
Current Research and Scholarly Interests
1. Multimodal optical imaging of bladder cancer
A major focus of my lab is to develop enhanced endoscopic imaging technologies (e.g. fluorescence, endomicroscopy, molecular imaging, computer vision, and artificial intelligence) to improve bladder tumor detection and resection. We have investigated CD47, an innate immune checkpoint, as a bladder cancer imaging and therapeutic target. We identified and validated CD47 as a promising cancer imaging target and proposed a strategy for intravesical administration of imaging agents based on therapeutic antibodies (Pan 2014). In animal models, we investigated the biodistribution and systemic toxicity of nanoparticle-labeled anti-CD47 (Pan 2017) and demonstrated that CD47-mediated near-infrared photoimmunotherapy, a novel form of targeted phototherapy, led to enhanced tumor destruction and prolonged survival (Kiss 2019). In the clinical arena, we pioneered the urological applications of confocal endomicroscopy for bladder cancer (Sonn 2009), upper tract urothelial carcinoma (Bui 2015) and prostate cancer (Lopez 2015). This optical biopsy technology enables real-time intraoperative imaging with spatial resolution comparable to histology. Finally, we are developing computer vision and artificial intelligence tools to enhance cystoscopic navigation and tumor identification. We have an ongoing effort to curate a high quality annotated cystoscopy imaging dataset of diverse bladder cancer variants and recently reported the first AI-assisted cystoscopy using convolutional neural networks for automated tumor annotation (Shkolyar 2019).
2. Precision diagnostics for bladder cancer
Another major focus is identification and validation of urine-based biomarkers to inform bladder cancer diagnosis, prognosis, and treatment response. Given its abundance and non-invasive nature of sample collection, urine serves as an ideal source of liquid biopsy. To overcome the diagnostic shortcomings of standard urine cytology, we have utilized high throughput sequencing technology as a discovery and diagnostic tool. We applied bulk RNA sequencing to urinary pellets for biomarker discovery and developed a diagnostic 3-marker urinary RNA panel (Sin 2017), and led a multi-center effort to validate another urinary RNA panel using an integrated microfluidic cartridge (Wallace 2019). Collaboratively with other colleagues at Stanford, we are developing an ultrasensitive targeted sequencing approach called uCAPP-Seq (urine tumor DNA Cancer Personalized Profiling by deep sequencing) for bladder cancer (Dudley 2019) and have started prospective longitudinal validation studies of these precision diagnostic platforms.
3. Precision diagnostics of urinary tract infections
A longstanding focus of my lab has been the development of molecular diagnostics for bacterial infections to direct evidence-based utilization of antibiotics and curtail the proliferation of multidrug resistant pathogens. We focus on urinary tract infections, the most common urological disease and healthcare-associated infection. We have made broad advances in molecular probe development for amplification-free bacterial detection, microfluidic-based antimicrobial susceptibility testing (AST), sample preparation strategies compatible with matrix effects from clinical samples, system integration, and single cell analysis. Representative works include rapid, sensitive pathogen identification through 16S rRNA targeting (Ouyang 2013, Mach 2019), validation of integrated AST in clinical samples (Altobelli 2016), and single cell analysis (Hsieh 2018, Li 2019). Most recently, we report a 30-minute sample-to-answer assay based on single-cell measurements of bacterial 16S rRNA in picoliter droplets to achieve simultaneous molecular pathogen identification and phenotypic antimicrobial susceptibility assessment (Kaushik 2021).
2024-25 Courses
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Independent Studies (5)
- Directed Reading in Urology
UROL 299 (Aut, Win, Spr, Sum) - Early Clinical Experience in Urology
UROL 280 (Aut, Win, Spr, Sum) - Graduate Research
UROL 399 (Aut, Win, Spr, Sum) - Medical Scholars Research
UROL 370 (Aut, Win, Spr, Sum) - Undergraduate Research
UROL 199 (Aut, Win, Spr, Sum)
- Directed Reading in Urology
Stanford Advisees
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Doctoral Dissertation Reader (AC)
Kevin Liu -
Postdoctoral Faculty Sponsor
Daniel Massana Roquero, Liang Qiu, Qingsong Yao -
Postdoctoral Research Mentor
Liang Qiu
All Publications
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Optimizing cystoscopy and TURBT: enhanced imaging and artificial intelligence.
Nature reviews. Urology
2024
Abstract
Diagnostic cystoscopy in combination with transurethral resection of the bladder tumour are the standard for the diagnosis, surgical treatment and surveillance of bladder cancer. The ability to inspect the bladder in its current form stems from a long chain of advances in imaging science and endoscopy. Despite these advances, bladder cancer recurrence and progression rates remain high after endoscopic resection. This stagnation is a result of the heterogeneity of cancer biology as well as limitations in surgical techniques and tools, as incomplete resection and provider-specific differences affect cancer persistence and early recurrence. An unmet clinical need remains for solutions that can improve tumour delineation and resection. Translational advances in enhanced cystoscopy technologies and artificial intelligence offer promising avenues to overcoming the progress plateau.
View details for DOI 10.1038/s41585-024-00904-9
View details for PubMedID 38982304
View details for PubMedCentralID 6889816
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Real-time Detection of Bladder Cancer Using Augmented Cystoscopy with Deep Learning: a Pilot Study.
Journal of endourology
2023
Abstract
Detection of bladder tumors under white light cystoscopy (WLC) is challenging yet impactful on treatment outcomes. Artificial intelligence (AI) holds the potential to improve tumor detection; however, its application in the real-time setting remains unexplored. AI has been applied to previously recorded images for post hoc analysis. In this study, we evaluate the feasibility of real-time AI integration during clinic cystoscopy and transurethral resection of bladder tumor (TURBT) on live, streaming video.Patients undergoing clinic flexible cystoscopy and TURBT were prospectively enrolled. A real-time alert device system (real-time CystoNet) was developed and integrated with standard cystoscopy towers. Streaming videos were processed in real time to display alert boxes in sync with live cystoscopy. The per-frame diagnostic accuracy was measured.Real-time CystoNet was successfully integrated in the operating room during TURBT and clinic cystoscopy in 50 consecutive patients. There were 55 procedures that met the inclusion criteria for analysis including 21 clinic cystoscopies and 34 TURBTs. For clinic cystoscopy, real-time CystoNet achieved per-frame tumor specificity of 98.8% with a median error rate of 3.6% (range: 0 - 47%) frames per cystoscopy. For TURBT, the per-frame tumor sensitivity was 52.9% and the per-frame tumor specificity was 95.4% with an error rate of 16.7% for cases with pathologically confirmed bladder cancers.The current pilot study demonstrates the feasibility of using a real-time AI system (real-time CystoNet) during cystoscopy and TURBT to generate active feedback to the surgeon. Further optimization of CystoNet for real-time cystoscopy dynamics may allow for clinically useful AI-augmented cystoscopy.
View details for DOI 10.1089/end.2023.0056
View details for PubMedID 37432899
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A magnetic hydrogel for the efficient retrieval of kidney stone fragments during ureteroscopy.
Nature communications
2023; 14 (1): 3711
Abstract
Only 60-75% of conventional kidney stone surgeries achieve complete stone-free status. Up to 30% of patients with residual fragments <2 mm in size experience subsequent stone-related complications. Here we demonstrate a stone retrieval technology in which fragments are rendered magnetizable with a magnetic hydrogel so that they can be easily retrieved with a simple magnetic tool. The magnetic hydrogel facilitates robust in vitro capture of stone fragments of clinically relevant sizes and compositions. The hydrogel components exhibit no cytotoxicity in cell culture and only superficial effects on ex vivo human urothelium and in vivo mouse bladders. Furthermore, the hydrogel demonstrates antimicrobial activity against common uropathogens on par with that of common antibiotics. By enabling the efficient retrieval of kidney stone fragments, our method can lead to improved stone-free rates and patient outcomes.
View details for DOI 10.1038/s41467-023-38936-1
View details for PubMedID 37349287
View details for PubMedCentralID 5853829
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Single-cell pathogen diagnostics for combating antibiotic resistance
NATURE REVIEWS METHODS PRIMERS
2023; 3 (1)
View details for DOI 10.1038/s43586-022-00190-y
View details for Web of Science ID 000925774700001
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Bladder cancer risk stratification using a urinary mRNA biomarker panel - A path towards cystoscopy triaging.
Urologic oncology
2021
Abstract
OBJECTIVES: The risk of bladder cancer (BCa) diagnosis and recurrence necessitates cystoscopy. Improved risk stratification may inform personalized triage and surveillance strategies. We aim to develop a urinary mRNA biomarker panel for risk stratification in patients undergoing BCa screening and surveillance.METHODS AND MATERIALS: Urine samples were collected from patients undergoing cystoscopy for BCa screening or surveillance. In patients who underwent transurethral resection of bladder tumor, urine samples were categorized based on tumor histopathology, size, and focality. Subjects with intermediate and high-risk BCa based on American Urological Association (AUA) guideline for non-muscle invasive bladder cancer were classified as "increased-risk"; those with no cancer and AUA low-risk BCa were classified as "low-risk". Urine was evaluated for ROBO1, WNT5A, CDC42BPB, ABL1, CRH, IGF2, ANXA10, and UPK1B expression. A diagnostic model to detect "increased-risk" BCa was created using forward logistic regression analysis of cycle threshold values. Model validation was performed with ten-fold cross-validation. Sensitivity and specificity for detection of "increased-risk" BCa was determined and net benefit analysis performed.RESULTS: Urine samples (n = 257) were collected from 177 patients (95 screening, 76 surveillance, 6 both). There were 65 diagnoses of BCa (12 low, 22 intermediate, 31 high risk). ROBO1, CRH, and IGF2 expression correlated with "increased-risk" disease yielding sensitivity of 92.5% (95% CI, 84.9%-98.1%) and specificity of 73.5% (95% CI, 67.7-79.9%). The overall calculated standardized net benefit of the model was 0.81 (95%CI, 0.71-0.90).CONCLUSIONS: A 3-marker urinary mRNA panel allows for non-invasive identification of "increased-risk" BCa and with further validation may prove to be a tool to reduce the need for cystoscopies in low-risk patients.
View details for DOI 10.1016/j.urolonc.2021.02.011
View details for PubMedID 33766467
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Droplet-Based Single-Cell Measurements of 16S rRNA Enable Integrated Bacteria Identification and Pheno-Molecular Antimicrobial Susceptibility Testing from Clinical Samples in 30 min
ADVANCED SCIENCE
2021
View details for DOI 10.1002/advs.202003419
View details for Web of Science ID 000613612200001
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CD47-targeted Near-Infrared Photoimmunotherapy for Human Bladder Cancer.
Clinical cancer research : an official journal of the American Association for Cancer Research
2019
Abstract
PURPOSE: Near-infrared photoimmunotherapy (NIR-PIT) is a localized molecular cancer therapy combining a photosensitizer-conjugated monoclonal antibody and light energy. CD47 is an innate immune checkpoint widely expressed on bladder cancer cells but absent from luminal normal urothelium. Targeting CD47 for NIR-PIT has the potential to selectively induce cancer cell death and minimize damage to normal urothelium.EXPERIMENTAL DESIGN: The cytotoxic effect of NIR-PIT with anti-CD47-IR700 was investigated in human bladder cancer cell lines and primary human bladder cancer cells derived from fresh surgical samples. Phagocytosis assays were performed to evaluate macrophage activity after NIR-PIT. Anti-CD47-IR700 was administered to murine xenograft tumor models of human bladder cancer for in vivo molecular imaging and NIR-PIT.RESULTS: Cytotoxicity in cell lines and primary bladder cancer cells significantly increased in a light-dose dependent manner with CD47-targeted NIR-PIT. Phagocytosis of cancer cells significantly increased with NIR-PIT compared to antibody alone (p=0.0002). In vivo fluorescence intensity of anti-CD47-IR700 in tumors reached a peak 24-hour post injection and was detectable for at least 14 days. After a single round of CD47-targeted NIR-PIT, treated animals showed significantly slower tumor growth compared to controls (p<0.0001). Repeated CD47-targeted NIR-PIT treatment further slowed tumor growth (p=0.0104) and improved survival compared to controls.CONCLUSION: CD47-targeted NIR-PIT increased direct cancer cell death and phagocytosis resulting in inhibited tumor growth and improved survival in a murine xenograft model of human bladder cancer.
View details for PubMedID 30890547
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Augmented Bladder Tumor Detection Using Deep Learning.
European urology
2019
Abstract
Adequate tumor detection is critical in complete transurethral resection of bladder tumor (TURBT) to reduce cancer recurrence, but up to 20% of bladder tumors are missed by standard white light cystoscopy. Deep learning augmented cystoscopy may improve tumor localization, intraoperative navigation, and surgical resection of bladder cancer. We aimed to develop a deep learning algorithm for augmented cystoscopic detection of bladder cancer. Patients undergoing cystoscopy/TURBT were recruited and white light videos were recorded. Video frames containing histologically confirmed papillary urothelial carcinoma were selected and manually annotated. We constructed CystoNet, an image analysis platform based on convolutional neural networks, for automated bladder tumor detection using a development dataset of 95 patients for algorithm training and five patients for testing. Diagnostic performance of CystoNet was validated prospectively in an additional 54 patients. In the validation dataset, per-frame sensitivity and specificity were 90.9% (95% confidence interval [CI], 90.3-91.6%) and 98.6% (95% CI, 98.5-98.8%), respectively. Per-tumor sensitivity was 90.9% (95% CI, 90.3-91.6%). CystoNet detected 39 of 41 papillary and three of three flat bladder cancers. With high sensitivity and specificity, CystoNet may improve the diagnostic yield of cystoscopy and efficacy of TURBT. PATIENT SUMMARY: Conventional cystoscopy has recognized shortcomings in bladder cancer detection, with implications for recurrence. Cystoscopy augmented with artificial intelligence may improve cancer detection and resection.
View details for DOI 10.1016/j.eururo.2019.08.032
View details for PubMedID 31537407
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Detection and surveillance of bladder cancer using urine tumor DNA.
Cancer discovery
2018
Abstract
Current regimens for the detection and surveillance of bladder cancer (BLCA) are invasive and have suboptimal sensitivity. Here, we present a novel high-throughput sequencing (HTS) method for detection of urine tumor DNA (utDNA) called utDNA CAPP-Seq (uCAPP-Seq) and apply it to 67 healthy adults and 118 patients with early-stage BLCA who either had urine collected prior to treatment or during surveillance. Using this targeted sequencing approach, we detected a median of 6 mutations per BLCA patient and observed surprisingly frequent mutations of the PLEKHS1 promoter (46%), suggesting these mutations represent a useful biomarker for detection of BLCA. We detected utDNA pre-treatment in 93% of cases using a tumor mutation-informed approach and in 84% when blinded to tumor mutation status, with 96-100% specificity. In the surveillance setting, we detected utDNA in 91% of patients who ultimately recurred, with utDNA detection preceding clinical progression in 92% of cases. uCAPP-Seq outperformed a commonly used ancillary test (UroVysion, p=0.02) and cytology and cystoscopy combined (p is less than or equal to 0.006), detecting 100% of BLCA cases detected by cytology and 82% that cytology missed. Our results indicate that uCAPP-Seq is a promising approach for early detection and surveillance of BLCA.
View details for PubMedID 30578357
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New and developing diagnostic technologies for urinary tract infections.
Nature reviews. Urology
2017
Abstract
Timely and accurate identification and determination of the antimicrobial susceptibility of uropathogens is central to the management of UTIs. Urine dipsticks are fast and amenable to point-of-care testing, but do not have adequate diagnostic accuracy or provide microbiological diagnosis. Urine culture with antimicrobial susceptibility testing takes 2-3 days and requires a clinical laboratory. The common use of empirical antibiotics has contributed to the rise of multidrug-resistant organisms, reducing treatment options and increasing costs. In addition to improved antimicrobial stewardship and the development of new antimicrobials, novel diagnostics are needed for timely microbial identification and determination of antimicrobial susceptibilities. New diagnostic platforms, including nucleic acid tests and mass spectrometry, have been approved for clinical use and have improved the speed and accuracy of pathogen identification from primary cultures. Optimization for direct urine testing would reduce the time to diagnosis, yet these technologies do not provide comprehensive information on antimicrobial susceptibility. Emerging technologies including biosensors, microfluidics, and other integrated platforms could improve UTI diagnosis via direct pathogen detection from urine samples, rapid antimicrobial susceptibility testing, and point-of-care testing. Successful development and implementation of these technologies has the potential to usher in an era of precision medicine to improve patient care and public health.
View details for DOI 10.1038/nrurol.2017.20
View details for PubMedID 28248946
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Endoscopic molecular imaging of human bladder cancer using a CD47 antibody.
Science translational medicine
2014; 6 (260): 260ra148-?
Abstract
A combination of optical imaging technologies with cancer-specific molecular imaging agents is a potentially powerful strategy to improve cancer detection and enable image-guided surgery. Bladder cancer is primarily managed endoscopically by white light cystoscopy with suboptimal diagnostic accuracy. Emerging optical imaging technologies hold great potential for improved diagnostic accuracy but lack imaging agents for molecular specificity. Using fluorescently labeled CD47 antibody (anti-CD47) as molecular imaging agent, we demonstrated consistent identification of bladder cancer with clinical grade fluorescence imaging systems, confocal endomicroscopy, and blue light cystoscopy in fresh surgically removed human bladders. With blue light cystoscopy, the sensitivity and specificity for CD47-targeted imaging were 82.9 and 90.5%, respectively. We detected variants of bladder cancers, which are diagnostic challenges, including carcinoma in situ, residual carcinoma in tumor resection bed, recurrent carcinoma following prior intravesical immunotherapy with Bacillus Calmette-Guérin (BCG), and excluded cancer from benign but suspicious-appearing mucosa. CD47-targeted molecular imaging could improve diagnosis and resection thoroughness for bladder cancer.
View details for DOI 10.1126/scitranslmed.3009457
View details for PubMedID 25355698
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Deconvolution of Human Urine across the Transcriptome and Metabolome.
Clinical chemistry
2024
Abstract
Early detection of the cell type changes underlying several genitourinary tract diseases largely remains an unmet clinical need, where existing assays, if available, lack the cellular resolution afforded by an invasive biopsy. While messenger RNA in urine could reflect the dynamic signal that facilitates early detection, current measurements primarily detect single genes and thus do not reflect the entire transcriptome and the underlying contributions of cell type-specific RNA.We isolated and sequenced the cell-free RNA (cfRNA) and sediment RNA from human urine samples (n = 6 healthy controls and n = 12 kidney stone patients) and measured the urine metabolome. We analyzed the resulting urine transcriptomes by deconvolving the noninvasively measurable cell type contributions and comparing to plasma cfRNA and the measured urine metabolome.Urine transcriptome cell type deconvolution primarily yielded relative fractional contributions from genitourinary tract cell types in addition to cell types from high-turnover solid tissues beyond the genitourinary tract. Comparison to plasma cfRNA yielded enrichment of metabolic pathways and a distinct cell type spectrum. Integration of urine transcriptomic and metabolomic measurements yielded enrichment for metabolic pathways involved in amino acid metabolism and overlapped with metabolic subsystems associated with proximal tubule function.Noninvasive whole transcriptome measurements of human urine cfRNA and sediment RNA reflects signal from hard-to-biopsy tissues exhibiting low representation in blood plasma cfRNA liquid biopsy at cell type resolution and are enriched in signal from metabolic pathways measurable in the urine metabolome.
View details for DOI 10.1093/clinchem/hvae137
View details for PubMedID 39383112
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Rapid Microbial Profiling through Multimodal Biosensors for Transversal Analysis.
Analytical chemistry
2024
Abstract
The intricate interactions between host and microbial communities hold significant implications for biology and medicine. However, traditional microbial profiling methods face limitations in processing time, measurement of absolute abundance, detection of low biomass, discrimination between live and dead cells, and functional analysis. This study introduces a rapid multimodal microbial characterization platform, Multimodal Biosensors for Transversal Analysis (MBioTA), for capturing the taxonomy, viability, and functional genes of the microbiota. The platform incorporates single cell biosensors, scalable microwell arrays, and automated image processing for rapid transversal analysis in as few as 2 h. The multimodal biosensors simultaneously characterize the taxon, viability, and functional gene expression of individual cells. By automating the image processing workflow, the single cell analysis techniques enable the quantification of bacteria with sensitivity down to 0.0075%, showcasing its capability in detecting low biomass samples. We illustrate the applicability of the MBioTA platform through the transversal analysis of the gut microbiota composition, viability, and functionality in a familial Alzheimer's disease mouse model. The effectiveness, rapid turnaround, and scalability of the MBioTA platform will facilitate its application from basic research to clinical diagnostics, potentially revolutionizing our understanding and management of diseases associated with microbe-host interactions.
View details for DOI 10.1021/acs.analchem.4c02449
View details for PubMedID 39007543
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ULTRASENSITIVE URINARY LIQUID BIOPSY ANALYSIS FOR BCG RESPONSE ASSESSMENT IN HIGH-RISK NON-MUSCLE INVASIVE BLADDER CANCER
LIPPINCOTT WILLIAMS & WILKINS. 2024: E1169
View details for Web of Science ID 001263885304019
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BACTERIA PROMOTES CALCIUM OXALATE CRYSTAL AGGREGATION THROUGH BIOFILM FORMATION
LIPPINCOTT WILLIAMS & WILKINS. 2024: E1037-E1038
View details for Web of Science ID 001263885303332
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DEVELOPING AN ANTIMICROBIAL IRRIGATION SOLUTION FOR ENDOUROLOGICAL PROCEDURES: EX VIVO EFFICACY AND IN VIVO SAFETY
LIPPINCOTT WILLIAMS & WILKINS. 2024: E1119-E1120
View details for Web of Science ID 001263885303485
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Ensuring Successful Biomarker Studies in Bladder Preservation Clinical Trials for Non-muscle Invasive Bladder Cancer.
Bladder cancer (Amsterdam, Netherlands)
2024; 10 (1): 1-8
View details for DOI 10.3233/BLC-230082
View details for PubMedID 38993535
View details for PubMedCentralID PMC11181871
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Electronic Documentation of Intraoperative Observation of Cystoscopic Procedures Using the cMDX Information System.
JCO clinical cancer informatics
2024; 8: e2300114
Abstract
PURPOSE: Accurate documentation of lesions during transurethral resection of bladder tumors (TURBT) is essential for precise diagnosis, treatment planning, and follow-up care. However, optimizing schematic documentation techniques for bladder lesions has received limited attention.MATERIALS AND METHODS: This prospective observational study used a cMDX-based documentation system that facilitates graphical representation, a lesion-specific questionnaire, and heatmap analysis with a posterization effect. We designed a graphical scheme for bladder covering bladder landmarks to visualize anatomic features and to document the lesion location. The lesion-specific questionnaire was integrated for comprehensive lesion characterization. Finally, spatial analyses were applied to investigate the anatomic distribution patterns of bladder lesions.RESULTS: A total of 97 TURBT cases conducted between 2021 and 2023 were included, identifying 176 lesions. The lesions were distributed in different bladder areas with varying frequencies. The distribution pattern, sorted by frequency, was observed in the following areas: posterior, trigone, lateral right and anterior, and lateral left and dome. Suspicious levels were assigned to the lesions, mostly categorized either as indeterminate or moderate. Lesion size analysis revealed that most lesions fell between 5 and 29 mm.CONCLUSION: The study highlights the potential of schematic documentation techniques for informed decision making, quality assessment, primary research, and secondary data utilization of intraoperative data in the context of TURBT. Integrating cMDX and heatmap analysis provides valuable insights into lesion distribution and characteristics.
View details for DOI 10.1200/CCI.23.00114
View details for PubMedID 38484216
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PolypMixNet: Enhancing semi-supervised polyp segmentation with polyp-aware augmentation.
Computers in biology and medicine
2024; 170: 108006
Abstract
AI-assisted polyp segmentation in colonoscopy plays a crucial role in enabling prompt diagnosis and treatment of colorectal cancer. However, the lack of sufficient annotated data poses a significant challenge for supervised learning approaches. Existing semi-supervised learning methods also suffer from performance degradation, mainly due to task-specific characteristics, such as class imbalance in polyp segmentation.The purpose of this work is to develop an effective semi-supervised learning framework for accurate polyp segmentation in colonoscopy, addressing limited annotated data and class imbalance challenges.We proposed PolypMixNet, a semi-supervised framework, for colorectal polyp segmentation, utilizing novel augmentation techniques and a Mean Teacher architecture to improve model performance. PolypMixNet introduces the polyp-aware mixup (PolypMix) algorithm and incorporates dual-level consistency regularization. PolypMix addresses the class imbalance in colonoscopy datasets and enhances the diversity of training data. By performing a polyp-aware mixup on unlabeled samples, it generates mixed images with polyp context along with their artificial labels. A polyp-directed soft pseudo-labeling (PDSPL) mechanism was proposed to generate high-quality pseudo labels and eliminate the dilution of lesion features caused by mixup operations. To ensure consistency in the training phase, we introduce the PolypMix prediction consistency (PMPC) loss and PolypMix attention consistency (PMAC) loss, enforcing consistency at both image and feature levels. Code is available at https://github.com/YChienHung/PolypMix.PolypMixNet was evaluated on four public colonoscopy datasets, achieving 88.97% Dice and 88.85% mIoU on the benchmark dataset of Kvasir-SEG. In scenarios where the labeled training data is limited to 15%, PolypMixNet outperforms the state-of-the-art semi-supervised approaches with a 2.88-point improvement in Dice. It also shows the ability to reach performance comparable to the fully supervised counterpart. Additionally, we conducted extensive ablation studies to validate the effectiveness of each module and highlight the superiority of our proposed approach.PolypMixNet effectively addresses the challenges posed by limited annotated data and unbalanced class distributions in polyp segmentation. By leveraging unlabeled data and incorporating novel augmentation and consistency regularization techniques, our method achieves state-of-the-art performance. We believe that the insights and contributions presented in this work will pave the way for further advancements in semi-supervised polyp segmentation and inspire future research in the medical imaging domain.
View details for DOI 10.1016/j.compbiomed.2024.108006
View details for PubMedID 38325216
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Ensuring Successful Biomarker Studies in Bladder Preservation Clinical Trials for Non-muscle Invasive Bladder Cancer
BLADDER CANCER
2024; 10 (1): 1-8
View details for DOI 10.3233/BLC-230082
View details for Web of Science ID 001208510500001
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Revealing hidden patterns in deep neural network feature space continuum via manifold learning.
Nature communications
2023; 14 (1): 8506
Abstract
Deep neural networks (DNNs) extract thousands to millions of task-specific features during model training for inference and decision-making. While visualizing these features is critical for comprehending the learning process and improving the performance of the DNNs, existing visualization techniques work only for classification tasks. For regressions, the feature points lie on a high dimensional continuum having an inherently complex shape, making a meaningful visualization of the features intractable. Given that the majority of deep learning applications are regression-oriented, developing a conceptual framework and computational method to reliably visualize the regression features is of great significance. Here, we introduce a manifold discovery and analysis (MDA) method for DNN feature visualization, which involves learning the manifold topology associated with the output and target labels of a DNN. MDA leverages the acquired topological information to preserve the local geometry of the feature space manifold and provides insightful visualizations of the DNN features, highlighting the appropriateness, generalizability, and adversarial robustness of a DNN. The performance and advantages of the MDA approach compared to the existing methods are demonstrated in different deep learning applications.
View details for DOI 10.1038/s41467-023-43958-w
View details for PubMedID 38129376
View details for PubMedCentralID 8791835
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Efficient Augmented Intelligence Framework for Bladder Lesion Detection.
JCO clinical cancer informatics
2023; 7: e2300031
Abstract
Development of intelligence systems for bladder lesion detection is cost intensive. An efficient strategy to develop such intelligence solutions is needed.We used four deep learning models (ConvNeXt, PlexusNet, MobileNet, and SwinTransformer) covering a variety of model complexity and efficacy. We trained these models on a previously published educational cystoscopy atlas (n = 312 images) to estimate the ratio between normal and cancer scores and externally validated on cystoscopy videos from 68 cases, with region of interest (ROI) pathologically confirmed to be benign and cancerous bladder lesions (ie, ROI). The performance measurement included specificity and sensitivity at frame level, frame sequence (block) level, and ROI level for each case.Specificity was comparable between four models at frame (range, 30.0%-44.8%) and block levels (56%-67%). Although sensitivity at the frame level (range, 81.4%-88.1%) differed between the models, sensitivity at the block level (100%) and ROI level (100%) was comparable between these models. MobileNet and PlexusNet were computationally more efficient for real-time ROI detection than ConvNeXt and SwinTransformer.Educational cystoscopy atlas and efficient models facilitate the development of real-time intelligence system for bladder lesion detection.
View details for DOI 10.1200/CCI.23.00031
View details for PubMedID 37774313
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Tumor detection under cystoscopy with transformer-augmented deep learning algorithm.
Physics in medicine and biology
2023; 68 (16)
Abstract
Objective.Accurate tumor detection is critical in cystoscopy to improve bladder cancer resection and decrease recurrence. Advanced deep learning algorithms hold the potential to improve the performance of standard white-light cystoscopy (WLC) in a noninvasive and cost-effective fashion. The purpose of this work is to develop a cost-effective, transformer-augmented deep learning algorithm for accurate detection of bladder tumors in WLC and to assess its performance on archived patient data.Approach.'CystoNet-T', a deep learning-based bladder tumor detector, was developed with a transformer-augmented pyramidal CNN architecture to improve automated tumor detection of WLC. CystoNet-T incorporated the self-attention mechanism by attaching transformer encoder modules to the pyramidal layers of the feature pyramid network (FPN), and obtained multi-scale activation maps with global features aggregation. Features resulting from context augmentation served as the input to a region-based detector to produce tumor detection predictions. The training set was constructed by 510 WLC frames that were obtained from cystoscopy video sequences acquired from 54 patients. The test set was constructed based on 101 images obtained from WLC sequences of 13 patients.Main results.CystoNet-T was evaluated on the test set with 96.4 F1 and 91.4 AP (Average Precision). This result improved the benchmark of Faster R-CNN and YOLO by 7.3 points in F1 and 3.8 points in AP. The improvement is attributed to the strong ability of global attention of CystoNet-T and better feature learning of the pyramids architecture throughout the training. The model was found to be particularly effective in highlighting the foreground information for precise localization of the true positives while favorably avoiding false alarmsSignificance.We have developed a deep learning algorithm that accurately detects bladder tumors in WLC. Transformer-augmented AI framework promises to aid in clinical decision-making for improved bladder cancer diagnosis and therapeutic guidance.
View details for DOI 10.1088/1361-6560/ace499
View details for PubMedID 37548023
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Long noncoding RNA MALAT1 is dynamically regulated in leader cells during collective cancer invasion.
Proceedings of the National Academy of Sciences of the United States of America
2023; 120 (27): e2305410120
Abstract
Cancer cells collectively invade using a leader-follower organization, but the regulation of leader cells during this dynamic process is poorly understood. Using a dual double-stranded locked nucleic acid (LNA) nanobiosensor that tracks long noncoding RNA (lncRNA) dynamics in live single cells, we monitored the spatiotemporal distribution of lncRNA during collective cancer invasion. We show that the lncRNA MALAT1 (metastasis-associated lung adenocarcinoma transcript 1) is dynamically regulated in the invading fronts of cancer cells and patient-derived spheroids. MALAT1 transcripts exhibit distinct abundance, diffusivity, and distribution between leader and follower cells. MALAT1 expression increases when a cancer cell becomes a leader and decreases when the collective migration process stops. Transient knockdown of MALAT1 prevents the formation of leader cells and abolishes the invasion of cancer cells. Taken together, our single-cell analysis suggests that MALAT1 is dynamically regulated in leader cells during collective cancer invasion.
View details for DOI 10.1073/pnas.2305410120
View details for PubMedID 37364126
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Laying the Groundwork for Optimized Surgical Feedback.
JAMA network open
2023; 6 (6): e2320465
View details for DOI 10.1001/jamanetworkopen.2023.20465
View details for PubMedID 37378988
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Conceptual Framework and Documentation Standards of Cystoscopic Media Content for Artificial Intelligence.
Journal of biomedical informatics
2023: 104369
Abstract
The clinical documentation of cystoscopy includes visual and textual materials. However, the secondary use of visual cystoscopic data for educational and research purposes remains limited due to inefficient data management in routine clinical practice.A conceptual framework was designed to document cystoscopy in a standardized manner with three major sections: data management, annotation management, and utilization management. A Swiss-cheese model was proposed for quality control and root cause analyses. We defined the infrastructure required to implement the framework with respect to FAIR (findable, accessible, interoperable, reusable) principles. We applied two scenarios exemplifying data sharing for research and educational projects to ensure compliance with FAIR principles.The framework was successfully implemented while following FAIR principles. The cystoscopy atlas produced from the framework could be presented in an educational web portal; a total of 68 full-length qualitative videos and corresponding annotation data were sharable for artificial intelligence projects covering frame classification and segmentation problems at case, lesion, and frame levels.Our study shows that the proposed framework facilitates the storage of visual documentation in a standardized manner and enables FAIR data for education and artificial intelligence research.
View details for DOI 10.1016/j.jbi.2023.104369
View details for PubMedID 37088456
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EFFICACY AND SAFETY OF A MAGNETIC HYDROGEL FOR STONE FRAGMENT REMOVAL: AN IN VITRO AND IN VIVO STUDY
LIPPINCOTT WILLIAMS & WILKINS. 2023: E819
View details for Web of Science ID 000994549502441
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ANTIMICROBIAL AND ANTIBIOFILM PROPERTIES OF CHITOSAN: AN EX VIVO STUDY ON KIDNEY STONES
LIPPINCOTT WILLIAMS & WILKINS. 2023: E45
View details for Web of Science ID 000994549500084
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Kawain Inhibits Urinary Bladder Carcinogenesis through Epigenetic Inhibition of LSD1 and Upregulation of H3K4 Methylation.
Biomolecules
2023; 13 (3)
Abstract
Epidemiological evidence suggests that kava (Piper methysticum Forst) drinks may reduce the risk of cancer in South Pacific Island smokers. However, little is known about the anti-carcinogenic effects of kava on tobacco smoking-related bladder cancer and its underlying mechanisms. Here we show that dietary feeding of kawain (a major active component in kava root extracts) to mice either before or after hydroxy butyl(butyl) nitrosamine (OH-BBN) carcinogen exposure slows down urinary bladder carcinogenesis and prolongs the survival of the OH-BBN-exposed mice. OH-BBN-induced bladder tumors exhibit significantly increased expression of lysine-specific demethylase 1 (LSD1), accompanied by decreased levels of H3K4 mono-methylation compared to normal bladder epithelium, whereas dietary kawain reverses the effects of OH-BBN on H3K4 mono-methylation. Human bladder cancer tumor tissues at different pathological grades also show significantly increased expression of LSD1 and decreased levels of H3K4 mono-methylation compared to normal urothelium. In addition, kava root extracts and the kavalactones kawain and methysticin all increase the levels of H3K4 mono- and di-methylation, leading to inhibitory effects on cell migration. Taken together, our results suggest that modification of histone lysine methylation may represent a new approach to bladder cancer prevention and treatment and that kavalactones may be promising agents for bladder cancer interception in both current and former smokers.
View details for DOI 10.3390/biom13030521
View details for PubMedID 36979456
View details for PubMedCentralID PMC10046577
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Passive monitoring by smart toilets for precision health.
Science translational medicine
2023; 15 (681): eabk3489
Abstract
Smart toilets are a key tool for enabling precision health monitoring in the home, but such passive monitoring has ethical considerations.
View details for DOI 10.1126/scitranslmed.abk3489
View details for PubMedID 36724240
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Is a restaging TURBT necessary in high-risk NMIBC if the initial TURBT was performed with blue light?
Urologic oncology
2023; 41 (2): 109.e9-109.e14
Abstract
To evaluate whether a restaging transurethral resection of bladder tumor (TURBT) is necessary in high-risk nonmuscle invasive bladder cancer (NMIBC) if the initial TURBT was performed using blue light (BL) technology.Using the multi-institutional Cysview registry between 2014 and 2021, all consecutive adult patients with known NMIBC (Ta and T1 disease) who underwent TURBT followed by a restaging TURBT within 8 weeks were reviewed. Patients were stratified according to their initial TURBT, BL vs. white light (WL), and compared to determine rates of residual disease and upstaging. Univariate analysis was performed using Mann-Whitney U and chi-square tests, with P < 0.05 considered significant.Overall, 115 patients had TURBT for NMIBC followed by a restaging TURBT within 8 weeks and were included in the analysis. Patients who underwent BL compared to WL for their initial TURBT had higher rates of benign pathology on restaging TURBT, although this was not statistically significant (47% vs. 30%; P = 0.08). Of patients with residual tumors on restaging TURBT, there were no differences in rates of Ta (22% vs. 26.5%; P = 0.62), T1 (22% vs. 26.5%; P = 0.62), or CIS (5.5% vs. 13%; P = 0.49) when the initial TURBT was done using BL compared to WL. Rates of upstaging to muscle invasive disease were also not different when initial TURBT was performed using BL compared to WL (3% vs. 4%; P = 0.78).TURBT using BL does not reduce rates of residual disease or risk of upstaging on restaging TURBT in Ta or T1 disease. Thus, a restaging TURBT is still necessary even if initial TURBT was performed using BL.
View details for DOI 10.1016/j.urolonc.2022.10.026
View details for PubMedID 36435710
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PlexusNet: A neural network architectural concept for medical image classification.
Computers in biology and medicine
2023; 154: 106594
Abstract
State-of-the-art (SOTA) convolutional neural network models have been widely adapted in medical imaging and applied to address different clinical problems. However, the complexity and scale of such models may not be justified in medical imaging and subject to the available resource budget. Further increasing the number of representative feature maps for the classification task decreases the model explainability. The current data normalization practice is fixed prior to model development and discounting the specification of the data domain. Acknowledging these issues, the current work proposed a new scalable model family called PlexusNet; the block architecture and model scaling by the network's depth, width, and branch regulate PlexusNet's architecture. The efficient computation costs outlined the dimensions of PlexusNet scaling and design. PlexusNet includes a new learnable data normalization algorithm for better data generalization. We applied a simple yet effective neural architecture search to design PlexusNet tailored to five clinical classification problems that achieve a performance noninferior to the SOTA models ResNet-18 and EfficientNet B0/1. It also does so with lower parameter capacity and representative feature maps in ten-fold ranges than the smallest SOTA models with comparable performance. The visualization of representative features revealed distinguishable clusters associated with categories based on latent features generated by PlexusNet. The package and source code are at https://github.com/oeminaga/PlexusNet.git.
View details for DOI 10.1016/j.compbiomed.2023.106594
View details for PubMedID 36753979
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Potential of educational cystoscopy atlas for augmented intelligence
2023
View details for DOI 10.1117/12.2650920
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Bladder Cancer and Artificial Intelligence: Emerging Applications
Urologic Clinics North America
2023
View details for DOI 10.1016/j.ucl.2023.07.002
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Flat lesion detection of white light cystoscopy with deep learning
2023
View details for DOI 10.1117/12.2650583
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Sequential modeling for cystoscopic image classification
2023
View details for DOI 10.1117/12.2649334
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An Efficient Framework for Video Documentation of Bladder Lesions for Cystoscopy: A Proof-of-Concept Study.
Journal of medical systems
2022; 46 (11): 73
Abstract
Processing full-length cystoscopy videos is challenging for documentation and research purposes. We therefore designed a surgeon-guided framework to extract short video clips with bladder lesions for more efficient content navigation and extraction. Screenshots of bladder lesions were captured during transurethral resection of bladder tumor, then manually labeled according to case identification, date, lesion location, imaging modality, and pathology. The framework used the screenshot to search for and extract a corresponding 10-seconds video clip. Each video clip included a one-second space holder with a QR barcode informing the video content. The success of the framework was measured by the secondary use of these short clips and the reduction of storage volume required for video materials. From 86 cases, the framework successfully generated 249 video clips from 230 screenshots, with 14 erroneous video clips from 8 screenshots excluded. The HIPPA-compliant barcodes provided information of video contents with a 100% data completeness. A web-based educational gallery was curated with various diagnostic categories and annotated frame sequences. Compared with the unedited videos, the informative short video clips reduced the storage volume by 99.5%. In conclusion, our framework expedites the generation of visual contents with surgeon's instruction for cystoscopy and potential incorporation of video data towards applications including clinical documentation, education, and research.
View details for DOI 10.1007/s10916-022-01862-8
View details for PubMedID 36190581
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Artificial Intelligence-Based Prognostic Model for Urologic Cancers: A SEER-Based Study.
Cancers
2022; 14 (13)
Abstract
BACKGROUND: Prognostication is essential to determine the risk profile of patients with urologic cancers.METHODS: We utilized the SEER national cancer registry database with approximately 2 million patients diagnosed with urologic cancers (penile, testicular, prostate, bladder, ureter, and kidney). The cohort was randomly divided into the development set (90%) and the out-held test set (10%). Modeling algorithms and clinically relevant parameters were utilized for cancer-specific mortality prognosis. The model fitness for the survival estimation was assessed using the differences between the predicted and observed Kaplan-Meier estimates on the out-held test set. The overall concordance index (c-index) score estimated the discriminative accuracy of the survival model on the test set. A simulation study assessed the estimated minimum follow-up duration and time points with the risk stability.RESULTS: We achieved a well-calibrated prognostic model with an overall c-index score of 0.800 (95% CI: 0.795-0.805) on the representative out-held test set. The simulation study revealed that the suggestions for the follow-up duration covered the minimum duration and differed by the tumor dissemination stages and affected organs. Time points with a high likelihood for risk stability were identifiable.CONCLUSIONS: A personalized temporal survival estimation is feasible using artificial intelligence and has potential application in clinical settings, including surveillance management.
View details for DOI 10.3390/cancers14133135
View details for PubMedID 35804904
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Diagnosis of Bloodstream Infections: An Evolution of Technologies towards Accurate and Rapid Identification and Antibiotic Susceptibility Testing.
Antibiotics (Basel, Switzerland)
2022; 11 (4)
Abstract
Bloodstream infections (BSI) are a leading cause of death worldwide. The lack of timely and reliable diagnostic practices is an ongoing issue for managing BSI. The current gold standard blood culture practice for pathogen identification and antibiotic susceptibility testing is time-consuming. Delayed diagnosis warrants the use of empirical antibiotics, which could lead to poor patient outcomes, and risks the development of antibiotic resistance. Hence, novel techniques that could offer accurate and timely diagnosis and susceptibility testing are urgently needed. This review focuses on BSI and highlights both the progress and shortcomings of its current diagnosis. We surveyed clinical workflows that employ recently approved technologies and showed that, while offering improved sensitivity and selectivity, these techniques are still unable to deliver a timely result. We then discuss a number of emerging technologies that have the potential to shorten the overall turnaround time of BSI diagnosis through direct testing from whole blood-while maintaining, if not improving-the current assay's sensitivity and pathogen coverage. We concluded by providing our assessment of potential future directions for accelerating BSI pathogen identification and the antibiotic susceptibility test. While engineering solutions have enabled faster assay turnaround, further progress is still needed to supplant blood culture practice and guide appropriate antibiotic administration for BSI patients.
View details for DOI 10.3390/antibiotics11040511
View details for PubMedID 35453262
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Smart toilets for monitoring COVID-19 surges: passive diagnostics and public health.
NPJ digital medicine
2022; 5 (1): 39
View details for DOI 10.1038/s41746-022-00582-0
View details for PubMedID 35354937
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Utility of Blue Light Cystoscopy for Post-bacillus Calmette-Guérin Bladder Cancer Recurrence Detection: Implications for Clinical Trial Recruitment and Study Comparisons.
The Journal of urology
2022; 207 (3): 534-540
Abstract
The utility of blue light cystoscopy (BLC) in patients receiving bacillus Calmette-Guérin (BCG) during post-treatment cystoscopy is not well understood. Our objective was to determine if BLC improves recurrence detection in patients with non-muscle invasive bladder cancer (NMIBC) undergoing BCG.Using the prospective multi-institutional Cysview® Registry (2014-2019), patients with NMIBC who received BCG within 1 year prior to BLC were identified. Primary outcomes were recurrences and whether lesions were detected on white light cystoscopy (WLC), BLC or both. We calculated the percentage of cystoscopies with recurrences that were missed with WLC alone. The cystoscopy-level BLC false-positive rate was the proportion of cystoscopies with biopsies only due to BLC suspicious lesions without recurrence.Of 1,703 BLCs, 282 cystoscopies were in the analytic cohort. The overall recurrence rate was 45.0% (127). With only WLC, 13% (16/127) of recurrences would have been missed as 5.7% (16/282) of cystoscopies performed had recurrence only identified with BLC. Among 16 patients with recurrence missed with WLC, 88% (14) had carcinoma in situ. The cystoscopy-level BLC false-positive rate was 5% (15).BLC helped detect recurrences after recent BCG that would have been missed with WLC alone. Providers should consider BLC for high-risk patients undergoing BCG and should discuss the risk of false-positives with these patients. As clinical trials of novel therapies for BCG-unresponsive disease increase and there are no clear guidelines on BLC use for post-treatment cystoscopies, it is important to consider how variable BLC use could affect enrollment in and comparisons of these studies.
View details for DOI 10.1097/JU.0000000000002308
View details for PubMedID 34694916
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Renal Morbidity Following Radical Cystectomy in Patients with Bladder Cancer.
European urology open science
1800; 35: 29-36
Abstract
Background: Patients with chronic kidney disease (CKD) are poor candidates for standard treatments for muscle-invasive bladder cancer (MIBC) and may be more likely to experience adverse outcomes when diagnosed with MIBC.Objective: To investigate factors associated with the development of advanced CKD following radical cystectomy.Design setting and participants: Using national Veterans Health Administration utilization files, we identified 3360 patients who underwent radical cystectomy for MIBC between 2004 and 2018.Outcome measurements and statistical analysis: We examined factors associated with the development of advanced CKD (estimated glomerular filtration rate [eGFR] of <30 ml/min/1.73 m2) after radical cystectomy using multivariable logistic and proportional hazard regression, with and without consideration of competing risks. We examined survival using Kaplan-Meier product limit estimates and proportional hazard regression.Results and limitations: The median age at surgery was 67 yr and the mean preoperative eGFR was 69.1 ± 20.3 ml/min/1.73 m2. Approximately three out of ten patients (n = 962, 29%) progressed to advanced CKD within 12 mo. Older age (hazard ratio [HR] per 5-yr increase 1.15, 95% confidence interval [CI] 1.10-1.20), preoperative hydronephrosis (HR 1.50, 95% CI 1.29-1.76), adjuvant chemotherapy (HR 1.19, 95% CI 1.00-1.41), higher comorbidity index (HR 1.13, 95% CI 1.11-1.16 per point), and lower baseline kidney function (HR 0.75, 95% CI 0.73-0.78) were associated with the development of advanced CKD. Baseline kidney function at the time of surgery was associated with survival. Generalizability is limited due to the predominantly male cohort.Conclusions: Impaired kidney function at baseline is associated with progression to advanced CKD and mortality after radical cystectomy. Preoperative kidney function should be incorporated into risk stratification algorithms for patients undergoing radical cystectomy.Patient summary: Impaired kidney function at baseline is associated with progression to advanced chronic kidney disease and mortality after radical cystectomy.
View details for DOI 10.1016/j.euros.2021.11.001
View details for PubMedID 35024629
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A Cascaded Droplet Microfluidic Platform Enables High-Throughput Single Cell Antibiotic Susceptibility Testing at Scale.
Small methods
2022; 6 (1): e2101254
Abstract
The global threat of antibiotic resistance underscores critical but unmet needs for rapid antibiotic susceptibility testing (AST) technologies. To this end, droplet microfluidic-based single-cell AST offers promise by achieving unprecedented rapidity, but its potential for clinical use is marred by the capacity of testing one to few antibiotic conditions per device, which falls short from the required scale in clinically relevant scenarios. To lift the scalability constraint in rapid single-cell AST technologies, a new cascaded droplet microfluidic platform that can streamline bacteria/antibiotic mixing, single-cell encapsulation within picoliter droplets, incubation, and detection in a continuous, assembly-line-like workflow is developed. The scalability of the platform is demonstrated by generating 32 groups of ≈10 000 droplets with custom antibiotic conditions within a single device, from which a new statistics-based method is used to analyze the single cell data and produce clinically useful antibiograms with minimum inhibitory concentrations in ≈90 min for the first antibiotic, plus 2 min for each subsequent antibiotic condition. Potential clinical utility of this platform is demonstrated by testing three clinical isolates and eight urine specimens against four frequently used antibiotics, and 100% and 93.8% categorical agreements are achieved compared to laboratory-based results that became available after 48 h.
View details for DOI 10.1002/smtd.202101254
View details for PubMedID 35041266
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Combating Antimicrobial Resistance via Single-Cell Diagnostic Technologies Powered by Droplet Microfluidics.
Accounts of chemical research
1800
Abstract
ConspectusAntimicrobial resistance is a global threat that if left unchecked could lead to 10 million annual mortalities by 2050. One factor contributing to the rise of multi-drug-resistant (MDR) pathogens is the reliance on traditional culture-based pathogen identification (ID) and antimicrobial susceptibility testing (AST) that typically takes several days. This delay of objective pathogen ID and AST information to inform clinical decision making results in clinicians treating patients empirically often using first-line, broad-spectrum antibiotics, contributing to the misuse/overuse of antibiotics. To combat the rise in MDR pathogens, there is a critical demand for rapid ID and AST technologies. Among the advances in ID and AST technologies in the past decade, single-cell diagnostic technologies powered by droplet microfluidics offer great promise due to their potential for high-sensitivity detection and rapid turnaround time. Our laboratory has been at the forefront of developing such technologies and applying them to diagnosing urinary tract infections (UTIs), one of the most common infections and a frequent reason for the prescription of antimicrobials. For pathogen ID, we first demonstrated the highly sensitive, amplification-free detection of single bacterial cells by confining them in picoliter-scale droplets and detection with fluorogenic peptide nucleic acid (PNA) probes that target their 16S rRNA (rRNA), a well-characterized marker for phylogenic classification. We subsequently improved the PNA probe design and enhanced detection sensitivity. For single-cell AST, we first employed a growth indicator dye and engineered an integrated device that allows us to detect growth from single bacterial cells under antibiotic exposure within 1 h, equivalent to two to three bacterial replications. To expand beyond testing a single antibiotic condition per device, a common limitation for droplet microfluidics, we developed an integrated programmable droplet microfluidic device for scalable single-cell AST. Using the scalable single-cell AST platform, we demonstrated the generation of up to 32 droplet groups in a single device with custom antibiotic titers and the capacity to scale up single-cell AST, and providing reliable pathogen categories beyond a binary call embodies a critical advance. Finally, we developed an integrated ID and AST platform. To this end, we developed a PNA probe panel that can identify nearly 90% of uropathogens and showed the quantitative detection of 16S rRNA from single bacterial cells in droplet-enabled AST after as little as 10 min of antibiotic exposure. This platform achieved both ID and AST from minimally processed urine samples in 30 min, representing one of the fastest turnaround times to date. In addition to tracing the development of our technologies, we compare them with contemporary research advances and offer our perspectives for future development, with the vision that single-cell ID and AST technologies powered by droplet microfluidics can indeed become a useful diagnostic tool for combating antimicrobial resistance.
View details for DOI 10.1021/acs.accounts.1c00462
View details for PubMedID 34898173
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A Cascaded Droplet Microfluidic Platform Enables High-Throughput Single Cell Antibiotic Susceptibility Testing at Scale
SMALL METHODS
2021
View details for DOI 10.1002/smtd.202101254
View details for Web of Science ID 000728705800001
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Postoperative opioid-free ureteroscopy discharge: A quality initiative pilot protocol.
Current urology
2021; 15 (3): 176-180
Abstract
Background: Opioids are commonly prescribed after ureteroscopy. With an increasing adoption of ureteroscopy for management of urolithiasis, this subset of patients is at high risk for opioid dependence. We sought to pilot an opioid-free discharge protocol for patients undergoing ureteroscopy for urolithiasis.Materials and methods: A prospective cohort study was performed of all patients undergoing ureteroscopy for urolithiasis and compared them to a historical control group. An opioid-free discharge protocol was initiated targeting all areas of surgical care from June 20th, 2019 to September 20th, 2019 as part of an institutional quality improvement initiative. Demographic and surgical data were collected as were morphine equivalent doses (MEDs) prescribed at discharge, postoperative measures including phone calls, clinic visits, and emergency room visits for pain.Results: Between October 1st, 2017 and February 1st, 2018, a total of 54 patients who underwent ureteroscopy were identified and comprised the historical control cohort while 54 prospective patients met the inclusion criteria since institution of the quality improvement initiative. There were no statistically significant differences in baseline patient demographics or surgical characteristics between the 2 patient groups. Total 37% of the intervention group had a preexisting opioid prescription versus 42.6% of the control group with no difference in preoperative MED (p = 0.55). The intervention group had a mean MED of 12.03 at discharge versus 110.5 in the control cohort (p ≤ 0.001). At discharge 3.7% of the intervention group received an opioid prescription versus 88.9% of the control group (p < 0.001). Overall, there was no difference in postoperative pain related phone calls (p = 1.0) or emergency room visits (p = 1.0).Conclusions: An opioid-free discharge protocol can dramatically reduce opioid prescription at discharge following ureteroscopy for urinary calculi without affecting postoperative measures such as phone calls, clinic visits, or subsequent prescriptions.
View details for DOI 10.1097/CU9.0000000000000025
View details for PubMedID 34552459
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Risk of Postpartum Urinary Stone Disease in Women with History of Urinary Stone Disease During Pregnancy.
Journal of endourology
2021
Abstract
OBJECTIVE: To determine the risk of postpartum urinary stone disease in women with a history of stone disease during pregnancy.METHODS: Using the Optum de-identified Clinformatics Datamart we identified pregnant women with urinary stone disease in the United States between January 2003 to December 2017 by standardized ICD-9, ICD-10, and CPT code criteria. We limited the cohort to include women without evidence of urinary stone disease prior to pregnancy. We abstracted patient demographic characteristics, clinical risk factors for stone disease, and data for urinary stone disease encounters and related procedures after pregnancy. Encounters occurring within 1 year of pregnancy were excluded. Cox proportional hazard models were used to analyze for significance.RESULTS: We identified a total of 1,395,783 pregnant women with a median postpartum follow-up of 4.0 years, including 5,971 (0.4%) women diagnosed with a urinary stone during pregnancy. Of these, 736 (12.3%) had an additional urinary stone diagnosis claim after pregnancy, compared with 13,275 (0.95%) women without a history of stone disease during pregnancy (p < 0.0001). In multivariable proportional hazards models urinary stone disease during pregnancy (HR 12.8, 95% CI [11.8 - 13.8]) was independently associated with a higher hazard of urinary stone disease after pregnancy.CONCLUSION: Women urinary stone disease during pregnancy were more likely to present with recurrent urinary stone disease after pregnancy. Given the 1 in 8 chance of needing further care, women with history of stone disease during pregnancy may benefit from risk counseling, surveillance, or secondary prevention efforts in the postpartum period.
View details for DOI 10.1089/end.2021.0223
View details for PubMedID 34235965
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Development and Validation of an Interpretable Artificial Intelligence Model to Predict 10-Year Prostate Cancer Mortality
CANCERS
2021; 13 (12)
Abstract
Prostate cancer treatment strategies are guided by risk-stratification. This stratification can be difficult in some patients with known comorbidities. New models are needed to guide strategies and determine which patients are at risk of prostate cancer mortality. This article presents a gradient-boosting model to predict the risk of prostate cancer mortality within 10 years after a cancer diagnosis, and to provide an interpretable prediction. This work uses prospective data from the PLCO Cancer Screening and selected patients who were diagnosed with prostate cancer. During follow-up, 8776 patients were diagnosed with prostate cancer. The dataset was randomly split into a training (n = 7021) and testing (n = 1755) dataset. Accuracy was 0.98 (±0.01), and the area under the receiver operating characteristic was 0.80 (±0.04). This model can be used to support informed decision-making in prostate cancer treatment. AI interpretability provides a novel understanding of the predictions to the users.
View details for DOI 10.3390/cancers13123064
View details for Web of Science ID 000666025900001
View details for PubMedID 34205398
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Facile syringe filter-enabled bacteria separation, enrichment, and buffer exchange for clinical isolation-free digital detection and characterization of bacterial pathogens in urine.
The Analyst
2021; 146 (8): 2475-2483
Abstract
The development of accelerated methods for pathogen identification (ID) and antimicrobial susceptibility testing (AST) for infectious diseases is necessary to facilitate evidence-based antibiotic therapy and reduce clinical overreliance on broad-spectrum antibiotics. Towards this end, droplet-based microfluidics has unlocked remarkably rapid diagnostic assays with single-cell and single-molecule resolution. Yet, droplet platforms invariably rely on testing purified bacterial samples that have been clinically isolated after lengthy (>16 h) plating. While plating-based clinical isolation is important for enriching and separating out bacteria from background in clinical samples and also facilitating buffer exchange, it creates a diagnostic bottleneck that ultimately precludes droplet-based methods from achieving significantly accelerated times-to-result. To alleviate this bottleneck, we have developed facile syringe filter-enabled strategies for bacterial separation, enrichment, and buffer exchange from urine samples. By selecting appropriately sized filter membranes, we separated bacterial cells from background particulates in urine samples and achieved up to 91% bacterial recovery after such 1-step filtration. When interfaced with droplet-based detection of bacterial cells, 1-step filtration improved the limit of detection for bacterial ID and quantification by over an order of magnitude. We also developed a facile buffer exchange strategy to prepare bacteria in urine samples for droplet-based AST that achieved up to 10-fold bacterial enrichment during buffer exchange. Our filtration strategies, can be easily integrated into droplet workflows, enable clinical isolation-free sample-to-answer ID and AST, and significantly accelerate the turnaround of standard infectious disease diagnostic workflows.
View details for DOI 10.1039/d1an00039j
View details for PubMedID 33899069
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Current Trends in Artificial Intelligence Application for Endourology and Robotic Surgery.
The Urologic clinics of North America
2021; 48 (1): 151–60
Abstract
With the advent of electronic medical records and digitalization of health care over the past 2decades, artificial intelligence (AI) has emerged as an enabling tool to manage complex datasets and deliver streamlined data-driven patient care. AI algorithms have the ability to extract meaningful signal from complex datasets through an iterative process akin to human learning. Through advancements over the past decade in deep learning, AI-driven innovations have accelerated applications in health care. Herein, the authors explore the development of these emerging AI technologies, focusing on the application of AI to endourology and robotic surgery.
View details for DOI 10.1016/j.ucl.2020.09.004
View details for PubMedID 33218590
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Longitudinal Follow-up and Performance Validation of a mRNA-based Urine Test (Xpert® Bladder Cancer Monitor) for surveillance in Non-Muscle Invasive Bladder Cancer Patients.
BJU international
2021
Abstract
Frequent recurrences and the potential for progression of non-muscle-invasive bladder cancer (NMIBC) demand close surveillance. This prospective study evaluated the performance of Xpert Bladder Cancer Monitor (Xpert) test as a predictor of tumor recurrence.Patients (n=429) undergoing surveillance for NMIBC underwent Xpert, cytology, and UroVysion testing. Patients with a positive Xpert and a negative cystoscopy (positive-negative group = PN; n=66) and control group of double negative patients (negative Xpert and cystoscopy results = NN) were followed for 12 months (+/- 90 days).Histology-confirmed recurrences were detected in 58 patients (13.5%). Xpert had an overall sensitivity of 60.3% and specificity of 76.5%. The sensitivity for high grade (HG) cancer was 87% with a negative predictive value (NPV) of 99%. Urine cytology showed an overall sensitivity of 23.2% (47.6% sensitivity for HG) and specificity of 88.3%. In the group of PN patients, 32% (n=21) developed a recurrence within 12 months, 11 of which were HG tumors. In the NN control group, 14% (n= 9) developed a recurrence and only 2 were HG tumors. The Hazard Ratio for developing recurrence in the PN group was 2.68 for all tumors and 6.84 for HG cancer.The Xpert test has a high sensitivity for detecting the recurrence of cancer and a high negative predictive value for excluding HG cancer. In addition, the data suggest that patients with a positive Xpert assay in setting of negative cystoscopy are at high risk for recurrence and need close surveillance.
View details for DOI 10.1111/bju.15418
View details for PubMedID 33793062
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A Rapid Single-Cell Antimicrobial Susceptibility Testing Workflow for Bloodstream Infections.
Biosensors
2021; 11 (8)
Abstract
Bloodstream infections are a significant cause of morbidity and mortality worldwide. The rapid initiation of effective antibiotic treatment is critical for patients with bloodstream infections. However, the diagnosis of bloodborne pathogens is largely complicated by the matrix effect of blood and the lengthy blood tube culture procedure. Here we report a culture-free workflow for the rapid isolation and enrichment of bacterial pathogens from whole blood for single-cell antimicrobial susceptibility testing (AST). A dextran sedimentation step reduces the concentration of blood cells by 4 orders of magnitude in 20-30 min while maintaining the effective concentration of bacteria in the sample. Red blood cell depletion facilitates the downstream centrifugation-based enrichment step at a sepsis-relevant bacteria concentration. The workflow is compatible with common antibiotic-resistant bacteria and does not influence the minimum inhibitory concentrations. By applying a microfluidic single-cell trapping device, we demonstrate the workflow for the rapid determination of bacterial infection and antimicrobial susceptibility testing at the single-cell level. The entire workflow from blood to categorical AST result can be completed in less than two hours.
View details for DOI 10.3390/bios11080288
View details for PubMedID 34436090
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Digital biomarkers in human excreta.
Nature reviews. Gastroenterology & hepatology
2021
View details for DOI 10.1038/s41575-021-00462-0
View details for PubMedID 33972768
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Evaluation of Patient Treatment Preferences for 15-20mm Kidney Stones: A Conjoint Analysis.
Journal of endourology
2020
Abstract
INTRODUCTION AND OBJECTIVE: Ureteroscopy (URS) and percutaneous nephrolithotomy (PCNL) are standard surgical treatments for intermediate-size (15-20mm) kidney stones but differ in their postoperative recovery, stone-free rates, and complication risks. We aimed to evaluate what affects patient treatment preferences.METHODS: Patients with urinary stone disease completed a choice-based conjoint analysis exercise assessing four treatment attributes associated with URS and PCNL. A sensitivity analysis using a market simulator was performed and the relative importance of each attribute was calculated. Differences in treatment preferences by demographic subgroup were assessed.RESULTS: A total of 58 patients completed the conjoint analysis exercise. Stone-free rate was the most important treatment attribute while length of hospital stay and cosmesis were less important. Overall, sensitivity analysis based on market simulation scenarios predicted almost equal preference for URS (52.4%) compared to PCNL (47.6%) for treatment of an intermediate-size stone. Older patients (>65 yo) expressed stronger preferences for lower infection rates and shorter hospital stays, and were more likely to prefer URS (67.2%, 95% CI: 52 - 82.5%) compared to younger patients (20-34 yo) (20.3%, 95% CI: 0 - 41.5%) who preferred higher procedure success rates and fewer repeat procedures.CONCLUSION: Conjoint analysis predicts nearly equal patient preference for URS or PCNL for the treatment of intermediate-size kidney stones. Older patients prefer the lower UTI risk and shorter hospital stay associated with URS, while younger patients prefer higher stone-free rates associated with PCNL. These results can help guide urologists in counseling patients and improve the shared decision-making process.
View details for DOI 10.1089/end.2020.0370
View details for PubMedID 32867549
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Development of robust artificial neural networks for prediction of 5-year survival in bladder cancer.
Urologic oncology
2020
Abstract
PURPOSE: When exploring survival outcomes for patients with bladder cancer, most studies rely on conventional statistical methods such as proportional hazards models. Given the successful application of machine learning to handle big data in many disciplines outside of medicine, we sought to determine if machine learning could be used to improve our ability to predict survival in bladder cancer patients. We compare the performance of artificial neural networks (ANN), a type of machine learning algorithm, with that of multivariable Cox proportional hazards (CPH) models in the prediction of 5-year disease-specific survival (DSS) and overall survival (OS) in patients with bladder cancer.SUBJECTS AND METHODS: The National Cancer Institute's Surveillance, Epidemiology, and End Results (SEER) 18 program database was queried to identify adult patients with bladder cancer diagnosed between 1995 and 2010, yielding 161,227 patients who met our inclusion criteria. ANNs were trained and tested on an 80/20 split of the dataset. Multivariable CPH models were developed in parallel. Variables used for prediction included age, sex, race, grade, SEER stage, tumor size, lymph node involvement, degree of extension, and surgery received. The primary outcomes were 5-year DSS and 5-year OS. Receiver operating characteristic curve analysis was conducted, and ANN models were tested for calibration.RESULTS: The area under the curve for the ANN models was 0.81 for the OS model and 0.80 for the DSS model. Area under the curve for the CPH models was 0.70 for OS and 0.81 for DSS. The ANN OS model achieved a calibration slope of 1.03 and a calibration intercept of -0.04, while the ANN DSS model achieved a calibration slope of 0.99 and a calibration intercept of -0.04.CONCLUSIONS: Machine learning algorithms can improve our ability to predict bladder cancer prognosis. Compared to CPH models, ANNs predicted OS more accurately and DSS with similar accuracy. Given the inherent limitations of administrative datasets, machine learning may allow for optimal interpretation of the complex data they contain.
View details for DOI 10.1016/j.urolonc.2020.05.009
View details for PubMedID 32593506
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Magrolimab and gemcitabine-cisplatin combination enhance phagocytic elimination of bladder cancer.
LIPPINCOTT WILLIAMS & WILKINS. 2020
View details for Web of Science ID 000560368306191
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SLIPS-LAB-A bioinspired bioanalysis system for metabolic evaluation of urinary stone disease.
Science advances
2020; 6 (21)
Abstract
Urinary stone disease is among the most common medical conditions. Standard evaluation of urinary stone disease involves a metabolic workup of stone formers based on measurement of minerals and solutes excreted in 24-hour urine samples. Nevertheless, 24-hour urine testing is slow, expensive, and inconvenient for patients, which has hindered widespread adoption in clinical practice. Here, we demonstrate SLIPS-LAB (Slippery Liquid-Infused Porous Surface Laboratory), a droplet-based bioanalysis system, for rapid measurement of urinary stone-associated analytes. The ultra-repellent and antifouling properties of SLIPS, which is a biologically inspired surface technology, allow autonomous liquid handling and manipulation of physiological samples without complicated sample preparation procedures and supporting equipment. We pilot a study that examines key urinary analytes in clinical samples from patients with urinary stone. The simplicity and speed of SLIPS-LAB hold the potential to provide actionable diagnostic information for patients with urinary stone disease and rapid feedback for responses to dietary and pharmacologic treatments.
View details for DOI 10.1126/sciadv.aba8535
View details for PubMedID 32937323
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Editorial Comment.
The Journal of urology
2020: 101097JU000000000000078601
View details for DOI 10.1097/JU.0000000000000786.01
View details for PubMedID 32282282
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REAL-TIME AUGMENTED BLADDER TUMOR DETECTION WITH DEEP LEARNING
LIPPINCOTT WILLIAMS & WILKINS. 2020: E1110
View details for Web of Science ID 000527010300445
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Prostate multiparametric magnetic resonance imaging features following partial gland cryoablation.
Urology
2020
Abstract
OBJECTIVES: To assess the qualitative and quantitative changes on prostate multiparametric magnetic resonance imaging (mpMRI) following partial gland ablation (PGA) with cryotherapy and correlate with histopathology.METHODS: We used 3D Slicer to generate prostate models and segment ipsilateral (treated) and contralateral peripheral and transition zones in ten men who underwent MRI/transrectal ultrasound fusion-guided PGA during 2017-2018. Pre and post-PGA volumes of prostate segments were compared. Post-PGA mpMRI were categorized according to PI-RADS v2 and treatment response on mpMRI was assessed in a manner similar to the radiology evaluation framework following liver lesion ablation.RESULTS: Median volume of ipsilateral peripheral and transition zones decreased from 10.9 mL and 13.0 mL to 7.2 mL and 10.8 mL (p=0.005), respectively. Median volume of contralateral peripheral and transition zones also decreased from 12.1 mL and 12.5 mL to 9.9 mL to 10.4 mL (p=0.005), respectively. Five men had clinically significant disease (Grade group ≥2) on post-PGA biopsy (three within treatment field and two outside). Of the men with clinically significant prostate cancer, mpMRI revealed PI-RADS 3 lesions in two. However, the treatment response framework did not detect residual disease.CONCLUSION: PGA results in asymmetric and significant reductions in prostate volume. Our results highlight the need for a separate assessment framework to enable standardization of the interpretation and reporting of post-PGA surveillance mpMRI. Moreover, our findings have significant implications for MRI-targeted surveillance biopsy following PGA with cryotherapy.
View details for DOI 10.1016/j.urology.2020.01.005
View details for PubMedID 31954170
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Robotic-Assisted Radical Prostatectomy Associated With Decreased Persistent Postoperative Opioid Use.
Journal of endourology
2020
Abstract
Minimally invasive surgery offers reduced pain and opioid use postoperatively compared to open surgery, but large-scale comparative studies are lacking. We assessed the incidence of persistent opioid use after open and robotic-assisted radical prostatectomy.We performed a retrospective claims database cohort study of opioid-naive (i.e., no opioid prescriptions 30-180 days before index surgery) adult males who underwent radical prostatectomy for prostate cancer from July 2013-June 2017. For patients who filled a perioperative opioid prescription (30 days before to 14 days after surgery), we calculated the incidence of new persistent postoperative opioid use (≥1 prescription 90-180 days after surgery). Multivariable logistic regression was performed to investigate the association between surgical approach, patient risk factors and persistent opioid use.12,278 radical prostatectomy patients filled an opioid prescription perioperatively (1510 [12%] open, 10,768 [88%] robotic-assisted). Of these, 846 (6.9%) patients continued to fill opioid prescription(s) 90-180 days after surgery. Patients undergoing robotic-assisted radical prostatectomy were 35% less likely to develop new persistent opioid use compared to those undergoing open radical prostatectomy (6.5% vs 9.7%; adjusted OR 0.65; 95% CI 0.54-0.79). Other independent risk factors included living in the southern, western or northcentral United States, preoperative comorbidity and tobacco use.Approximately 6.9% of opioid-naive patients continued to fill opioid prescriptions 90 days after radical prostatectomy. The risk of persistent opioid use was significantly lower among patients undergoing a robotic-assisted versus open approach. Further efforts are needed to develop postoperative opioid prescription protocols for patients undergoing radical prostatectomy.
View details for DOI 10.1089/end.2019.0788
View details for PubMedID 32066277
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SLIPS-LAB-A bioinspired bioanalysis system for metabolic evaluation of urinary stone disease.
Science advances
2020; 6 (21): eaba8535
Abstract
Urinary stone disease is among the most common medical conditions. Standard evaluation of urinary stone disease involves a metabolic workup of stone formers based on measurement of minerals and solutes excreted in 24-hour urine samples. Nevertheless, 24-hour urine testing is slow, expensive, and inconvenient for patients, which has hindered widespread adoption in clinical practice. Here, we demonstrate SLIPS-LAB (Slippery Liquid-Infused Porous Surface Laboratory), a droplet-based bioanalysis system, for rapid measurement of urinary stone-associated analytes. The ultra-repellent and antifouling properties of SLIPS, which is a biologically inspired surface technology, allow autonomous liquid handling and manipulation of physiological samples without complicated sample preparation procedures and supporting equipment. We pilot a study that examines key urinary analytes in clinical samples from patients with urinary stone. The simplicity and speed of SLIPS-LAB hold the potential to provide actionable diagnostic information for patients with urinary stone disease and rapid feedback for responses to dietary and pharmacologic treatments.
View details for DOI 10.1126/sciadv.aba8535
View details for PubMedID 32494753
View details for PubMedCentralID PMC7244315
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Urinary Stone Disease in Pregnancy: Current Management Practices in a Large National Cohort.
Urology
2020
Abstract
To define current national practice patterns of imaging modalities and urologic procedures in pregnant women with urinary stone disease.Using the IBM® MarketScan® national insurance claims database, we identified pregnant women with urinary stone disease and their corresponding gestational age between 2011-2016 using administrative claims data. We then assessed each encounter for urinary stone disease or stone-related urologic procedure during their pregnancy. We abstracted demographic information as well as codes for stone procedures and imaging.We identified 14,298 pregnant women with urinary stone disease during the study period. Of the 12,315 undergoing abdominal imaging (86.1%), magnetic resonance imaging (MRI) in 2.8%, x-ray in 9%, and ultrasound in 74.3%. Computed tomography was not used as a diagnostic modality during pregnancy. Procedural intervention was performed in 749 women (5.2%): 476 (3.3%) ureteral stent placement without definitive stone treatment, 93 (0.6%) percutaneous nephrostomy placement, and 180 (1.3%) ureteroscopy (URS) for definitive stone treatment. URS was most commonly performed before 34 weeks gestation with only 27 cases (15%) performed after.This large national cohort reveals the current imaging and procedural practice patterns for urinary stone disease during pregnancy and provides a critical baseline as these practice patterns evolve in the future.
View details for DOI 10.1016/j.urology.2020.03.050
View details for PubMedID 32311447
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Urinary Stone Disease in Pregnancy: A Claims-Based Analysis of 1.4 Million Patients.
The Journal of urology
2019: 101097JU0000000000000657
Abstract
PURPOSE: Urinary stone disease during pregnancy is poorly understood but is thought to be associated with increased maternal and fetal morbidity. We sought to determine the prevalence of urinary stone disease in pregnancy and whether urinary stone disease during pregnancy is associated with adverse pregnancy outcomes.MATERIALS AND METHODS: We identified all pregnant women from 2003 through 2017 in the Optum national insurance claims database. We used diagnosis claims to identify urinary stone disease and assess medical comorbidity. We established the prevalence of urinary stone disease during pregnancy, stratified by week of pregnancy. We further evaluated associations among urinary stone disease and maternal complications and pregnancy outcomes in both univariable and multivariable analyses.RESULTS: Urinary stone disease affects 8/1000 pregnancies and is more common in white women and women with more comorbid conditions. In fully adjusted models, pregnancies complicated by urinary stone disease had higher rates of adverse fetal outcomes, including prematurity and spontaneous abortions. This analysis is limited by its retrospective administrative claims design.CONCLUSIONS: The rate of urinary stone disease during pregnancy is higher than previously reported. Urinary stone disease is associated with adverse pregnancy outcomes.
View details for DOI 10.1097/JU.0000000000000657
View details for PubMedID 31738114
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Simultaneous transrectal ultrasound and photoacoustic human prostate imaging.
Science translational medicine
2019; 11 (507)
Abstract
Imaging technologies that simultaneously provide anatomical, functional, and molecular information are emerging as an attractive choice for disease screening and management. Since the 1980s, transrectal ultrasound (TRUS) has been routinely used to visualize prostatic anatomy and guide needle biopsy, despite limited specificity. Photoacoustic imaging (PAI) provides functional and molecular information at ultrasonic resolution based on optical absorption. Combining the strengths of TRUS and PAI approaches, we report the development and bench-to-bedside translation of an integrated TRUS and photoacoustic (TRUSPA) device. TRUSPA uses a miniaturized capacitive micromachined ultrasonic transducer array for simultaneous imaging of anatomical and molecular optical contrasts [intrinsic: hemoglobin; extrinsic: intravenous indocyanine green (ICG)] of the human prostate. Hemoglobin absorption mapped vascularity of the prostate and surroundings, whereas ICG absorption enhanced the intraprostatic photoacoustic contrast. Future work using the TRUSPA device for biomarker-specific molecular imaging may enable a fundamentally new approach to prostate cancer diagnosis, prognostication, and therapeutic monitoring.
View details for DOI 10.1126/scitranslmed.aav2169
View details for PubMedID 31462508
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Adaptable microfluidic system for single-cell pathogen classification and antimicrobial susceptibility testing
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
2019; 116 (21): 10270–79
View details for DOI 10.1073/pnas.1819569116
View details for Web of Science ID 000468403400020
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Nanotube assisted microwave electroporation for single cell pathogen identification and antimicrobial susceptibility testing
NANOMEDICINE-NANOTECHNOLOGY BIOLOGY AND MEDICINE
2019; 17: 246–53
View details for DOI 10.1016/j.nano.2019.01.015
View details for Web of Science ID 000467581100020
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THE EPIDEMIOLOGY OF URINARY STONE DISEASE IN PREGNANCY: A CLAIMS-BASED ANALYSIS OF 1.2 MILLION PATIENTS
LIPPINCOTT WILLIAMS & WILKINS. 2019: E846
View details for Web of Science ID 000473345202559
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Optimizing peptide nucleic acid probes for hybridization-based detection and identification of bacterial pathogens
ANALYST
2019; 144 (5): 1565–74
View details for DOI 10.1039/c8an02194e
View details for Web of Science ID 000461614000006
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Prevalence of twenty-four hour urine testing in Veterans with urinary stone disease.
PloS one
2019; 14 (8): e0220768
Abstract
The American Urological Association guidelines recommend 24-hour urine testing in patients with urinary stone disease to decrease the risk of stone recurrence; however, national practice patterns for 24-hour urine testing are not well characterized. Our objective is to determine the prevalence of 24-hour urine testing in patients with urinary stone disease in the Veterans Health Administration and examine patient-specific and facility-level factors associated with 24-hour urine testing. Identifying variations in clinical practice can inform future quality improvement efforts in the management of urinary stone disease in integrated healthcare systems.We accessed national Veterans Health Administration data through the Corporate Data Warehouse (CDW), hosted by the Veterans Affairs Informatics and Computing Infrastructure (VINCI), to identify patients with urinary stone disease. We defined stone formers as Veterans with one inpatient ICD-9 code for kidney or ureteral stones, two or more outpatient ICD-9 codes for kidney or ureteral stones, or one or more CPT codes for kidney or ureteral stone procedures from 2007 through 2013. We defined a 24-hour urine test as a 24-hour collection for calcium, oxalate, citrate or sulfate. We used multivariable regression to assess demographic, geographic, and selected clinical factors associated with 24-hour urine testing.We identified 130,489 Veterans with urinary stone disease; 19,288 (14.8%) underwent 24-hour urine testing. Patients who completed 24-hour urine testing were younger, had fewer comorbidities, and were more likely to be White. Utilization of 24-hour urine testing varied widely by geography and facility, the latter ranging from 1 to 40%.Fewer than one in six patients with urinary stone disease complete 24-hour urine testing in the Veterans Health Administration. In addition, utilization of 24-hour urine testing varies widely by facility identifying a target area for improvement in the care of patients with urinary stone disease. Future efforts to increase utilization of 24-hour urine testing and improve clinician awareness of targeted approaches to stone prevention may be warranted to reduce the morbidity and cost of urinary stone disease.
View details for DOI 10.1371/journal.pone.0220768
View details for PubMedID 31393935
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Twenty-Four Hour Urine Testing and Prescriptions for Urinary Stone Disease-Related Medications in Veterans.
Clinical journal of the American Society of Nephrology : CJASN
2019
Abstract
Current guidelines recommend 24-hour urine testing in the evaluation and treatment of persons with high-risk urinary stone disease. However, how much clinicians use information from 24-hour urine testing to guide secondary prevention strategies is unknown. We sought to determine the degree to which clinicians initiate or continue stone disease-related medications in response to 24-hour urine testing.We examined a national cohort of 130,489 patients with incident urinary stone disease in the Veterans Health Administration between 2007 and 2013 to determine whether prescription patterns for thiazide diuretics, alkali therapy, and allopurinol changed in response to 24-hour urine testing.Stone formers who completed 24-hour urine testing (n=17,303; 13%) were significantly more likely to be prescribed thiazide diuretics, alkali therapy, and allopurinol compared with those who did not complete a 24-hour urine test (n=113,186; 87%). Prescription of thiazide diuretics increased in patients with hypercalciuria (9% absolute increase if urine calcium 201-400 mg/d; 21% absolute increase if urine calcium >400 mg/d, P<0.001). Prescription of alkali therapy increased in patients with hypocitraturia (24% absolute increase if urine citrate 201-400 mg/d; 34% absolute increase if urine citrate ≤200 mg/d, P<0.001). Prescription of allopurinol increased in patients with hyperuricosuria (18% absolute increase if urine uric acid >800 mg/d, P<0.001). Patients who had visited both a urologist and a nephrologist within 6 months of 24-hour urine testing were more likely to have been prescribed stone-related medications than patients who visited one, the other, or neither.Clinicians adjust their treatment regimens in response to 24-hour urine testing by increasing the prescription of medications thought to reduce risk for urinary stone disease. Most patients who might benefit from targeted medications remain untreated.
View details for DOI 10.2215/CJN.03580319
View details for PubMedID 31712387
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Optical biopsy of penile cancer with in vivo confocal laser endomicroscopy.
Urologic oncology
2019
Abstract
Surgical management of penile cancer depends on accurate margin assessment and staging. Advanced optical imaging technologies may improve penile biopsy and organ-sparing treatment. We evaluated the feasibility of confocal laser endomicroscopy for intraoperative assessment of benign and malignant penile tissue.With institutional review board approval, 11 patients were recruited, 9 with suspected penile cancer, and 2 healthy controls. Confocal laser endomicroscopy using a 2.6-mm fiber-optic probe was performed at 1 or 2 procedures on all subjects, for 13 imaging procedures. Fluorescein was administered intravenously approximately 3 minutes prior to imaging for contrast. Video sequences from in vivo (n = 12) and ex vivo (n = 6) imaging were obtained of normal glans, suspicious lesions, and surgical margins. Images were processed, annotated, characterized, and correlated with standard hematoxylin and eosin histopathology.No adverse events related to imaging were reported. Distinguishing features of benign and malignant penile tissue could be identified by confocal laser endomicroscopy. Normal skin had cells of uniform size and shape, with distinct cytoplasmic membranes consistent with squamous epithelium. Malignant lesions were characterized by disorganized, crowded cells of various size and shape, lack of distinct cytoplasmic membranes, and hazy, moth-eaten appearance. The transition from normal to abnormal squamous epithelium could be identified.We report the initial feasibility of intraoperative confocal laser endomicroscopy for penile cancer optical biopsy. Pending further evaluation, confocal laser endomicroscopy could serve as an adjunct or replacement to conventional frozen section pathology for management of penile cancer.
View details for DOI 10.1016/j.urolonc.2019.08.018
View details for PubMedID 31537485
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Organoid Modeling of the Tumor Immune Microenvironment.
Cell
2018; 175 (7): 1972
Abstract
Invitro cancer cultures, including three-dimensional organoids, typically contain exclusively neoplastic epithelium but require artificial reconstitution to recapitulate the tumor microenvironment (TME). The co-culture of primary tumor epithelia with endogenous, syngeneic tumor-infiltrating lymphocytes (TILs) as a cohesive unit has been particularly elusive. Here, an air-liquid interface (ALI) method propagated patient-derived organoids (PDOs) from >100 human biopsies or mouse tumors in syngeneic immunocompetent hosts as tumor epithelia with native embedded immune cells (T, B, NK, macrophages). Robust droplet-based, single-cell simultaneous determination of gene expression and immune repertoire indicated that PDO TILs accurately preserved the original tumor Tcell receptor (TCR) spectrum. Crucially, human and murine PDOs successfully modeled immune checkpoint blockade (ICB) with anti-PD-1- and/or anti-PD-L1 expanding and activating tumor antigen-specific TILs and eliciting tumor cytotoxicity. Organoid-based propagation of primary tumor epithelium en bloc with endogenous immune stroma should enable immuno-oncology investigations within the TME and facilitate personalized immunotherapy testing.
View details for PubMedID 30550791
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Surface-Enhanced Raman Scattering Nanoparticles for Multiplexed Imaging of Bladder Cancer Tissue Permeability and Molecular Phenotype.
ACS nano
2018
Abstract
Bladder cancer has the highest recurrence rate of all cancers due in part to inadequate transurethral resection. Inadequate resection is caused by the inability of cystoscopes to detect invisible lesions during the resection procedure. To improve detection and resection of nonmuscle invasive bladder cancer, we quantified the ability of a surface-enhanced Raman nanoparticle and endoscope system to classify bladder tissue as normal or cancerous. Both antibody-based (active) and tissue permeability-based (passive) targeting mechanisms were evaluated by topically applying nanoparticles to ex vivo human bladder tissue samples. Multiplexed molecular imaging of CD47 and Carbonic Anhydrase 9 tumor proteins gave a receiver operating characteristic area under the curve (ROC AUC of 0.93 (0.75, 1.00). Furthermore, passively targeted nanoparticles enabled tissue classification with an ROC AUC of 0.93 (0.73, 1.00). Passively targeted nanoparticles penetrated 5-fold deeper and bound to tumor tissue at 3.3-fold higher concentrations in cancer compared to normal bladder urothelium, suggesting the existence of an enhanced surface permeability and retention effect in human bladder cancer.
View details for PubMedID 30203645
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Rapid Microbiology Screening in Pharmaceutical Workflows.
SLAS technology
2018; 23 (4): 387-394
Abstract
Recently advances in miniaturization and automation have been utilized to rapidly decrease the time to result for microbiology testing in the clinic. These advances have been made due to the limitations of conventional culture-based microbiology methods, including agar plate and microbroth dilution, which have long turnaround times and require physicians to treat patients empirically with antibiotics before test results are available. Currently, there exist similar limitations in pharmaceutical sterility and bioburden testing, where the long turnaround times associated with standard microbiology testing drive costly inefficiencies in workflows. These include the time lag associated with sterility screening within drug production lines and the warehousing cost and time delays within supply chains during product testing. Herein, we demonstrate a proof-of-concept combination of a rapid microfluidic assay and an efficient cell filtration process that enables a path toward integrating rapid tests directly into pharmaceutical microbiological screening workflows. We demonstrate separation and detection of Escherichia coli directly captured and analyzed from a mammalian (i.e., CHO) cell culture with a 3.0 h incubation. The demonstration is performed using a membrane filtration module that is compatible with sampling from bioreactors, enabling in-line sampling and process monitoring.
View details for DOI 10.1177/2472630318779758
View details for PubMedID 30027813
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Blue light cystoscopy for the diagnosis of bladder cancer: Results from the US prospective multicenter registry.
Urologic oncology
2018
Abstract
Blue light cystoscopy (BLC) using hexaminolevulinate (HAL/Cysview/Hexvix) has been previously shown to improve detection of non-muscle-invasive bladder cancer (NMIBC). Herein, we evaluated the detection of malignant lesions in a heterogenous group of patients in the real world setting and documented the change in risk category due to upstaging or upgrading.Prospective enrollment during April 2014 to December 2016 of consecutive adult patients with suspected or known non-muscle-invasive bladder cancer based on prior cystoscopy or imaging, undergoing transurethral resection of bladder tumor at 9 different referral medical centers. HAL was instilled in the bladder for 1 to 3 hours before evacuation and inspection. Sensitivity and specificity of BLC, white light cystoscopy (WLC), and the combination of both BLC and WLC for detection of any malignancy was reported on final pathology. Number of patients with a change in American Urological Association (AUA) risk category based on BLC findings leading to a possible change in management and adverse events were recorded.Overall, 1,632 separate samples from bladder resection or biopsy were identified from 641 BLC procedures on 533 patients: 85 (16%) underwent repeat BLC (range: 2-5). Sensitivity of WLC, BLC, and the combination for diagnosis of any malignant lesion was 76%, 91%, and 98.5%, respectively. Addition of BLC to standard WLC increased detection rate by 12% for any papillary lesion and 43% for carcinoma in-situ. Within the WLC negative group, an additional 206 lesions in 133 (25%) patients were detected exclusively with BLC. In multifocal disease, BLC resulted in AUA risk-group migration occurred in 33 (6%) patients and a change in recommended management in 74 (14%). False-positive rate was 25% for WLC and 30% for BLC. One mild dermatologic hypersensitivity reaction (0.2%).BLC increases detection rates of carcinoma in-situ and papillary lesions over WLC alone and can change management in 14% of cases. Repeat use of HAL for BLC is safe.
View details for DOI 10.1016/j.urolonc.2018.04.013
View details for PubMedID 29859728
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HUMANIZED ANTI-CD47 ANTIBODY (HU-5F9-G4) FOR METASTATIC BLADDER CANCER IS SUPERIOR TO CONVENTIONAL CHEMOTHERAPY WITH CISPLATIN AND GEMCITABINE IN A MURINE BLADDER CANCER MODEL.
ELSEVIER SCIENCE INC. 2018: E864
View details for Web of Science ID 000429166602468
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Unplanned Emergency Department Visits and Hospital Admissions Following Ureteroscopy: Do Ureteral Stents Make a Difference?
Urology
2018
Abstract
The comparative effectiveness of ureteral stents placed during ureteroscopy for urinary stone disease is widely debated. We sought to evaluate unplanned medical visits within the early post-operative period after ureteroscopy in patients with and without ureteral stent placement.We identified all ureteroscopic procedures for urinary stone disease in the California Office of Statewide Health Planning and Development (OSHPD) database from 2010-2012. The primary outcome was any emergency department visit or inpatient hospital admission in the first 7 days following ureteroscopy. Patients were sub-categorized by type of ureteroscopy (i.e. laser lithotripsy versus basket retrieval) and analyzed for significant differences between stented and unstented patients. Multivariable logistic regression was performed to determine if ureteral stent placement was independently associated with unplanned visits.Our analytic cohort included 16,060 patients undergoing 17,716 ureteroscopy procedures. A ureteral stent was placed in 86.2% of patients undergoing laser lithotripsy, and 70.5% of patients receiving basket retrieval. In the 7 days following ureteroscopy, 6.6% of patients were seen in the emergency department and 2.2% of patients were admitted to a hospital. In a fully adjusted model, the utilization of a ureteral stent was not associated with emergency department visits or inpatient admissions.Ureteral stent placement during ureteroscopy is not associated with an increased odds of emergency department visits and inpatient admissions in the early post-operative period.
View details for PubMedID 29601836
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Optical and Cross-Sectional Imaging Technologies for Bladder Cancer.
Cancer treatment and research
2018; 175: 139–63
Abstract
Optical and cross-sectional imaging plays critical roles in bladder cancer diagnostics. White light cystoscopy remains the cornerstone for the management of non-muscle-invasive bladder cancer. In the last decade, significant technological improvements have been introduced for optical imaging to address the known shortcomings of white light cystoscopy. Enhanced cystoscopy modalities such as blue light cystoscopy and narrowband imaging survey a large area of the urothelium and provide contrast enhancement to detect additional lesions and decrease cancer recurrence. However, higher false-positive rates accompany the gain of sensitivity. Optical biopsy technologies, including confocal laser endomicroscopy and optical coherence tomography, provide cellular resolutions combined with subsurface imaging, thereby enabling optical-based cancer characterization, and may lead to real-time cancer grading and staging. Coupling of fluorescently labeled binding agents with optical imaging devices may translate into high molecular specificity, thus enabling visualization and characterization of biological processes at the molecular level. For cross-sectional imaging, upper urinary tract evaluation and assessment potential extravesical tumor extension and metastases are currently the primary roles, particularly for management of muscle-invasive bladder cancer. Multi-parametric MRI, including dynamic gadolinium-enhanced and diffusion-weighted sequences, has been investigated for primary bladder tumor detection. Ultrasmall superparamagnetic particles of iron oxide (USPIO) are a new class of contrast agents that increased the accuracy of lymph node imaging. Combination of multi-parametric MRI with positron emission tomography is on the horizon to improve accuracy rates for primary tumor diagnostics as well as lymph node evaluation. As these high-resolution optical and cross-sectional technologies emerge and develop, judicious assessment and validation await for their clinical integration toward improving the overall management of bladder cancer.
View details for PubMedID 30168121
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Validation of Confocal Laser Endomicroscopy Features of Bladder Cancer: The Next Step Towards Real-time Histologic Grading.
European urology focus
2018
Abstract
Cystoscopy enables the visualisation of suspicious bladder lesions but lacks the ability to provide real-time histopathologic information. Confocal laser endomicroscopy (CLE) is a probe-based optical technique that can provide real-time microscopic images. This high-resolution optical imaging technique may enable real-time tumour grading during cystoscopy.To validate and adapt CLE criteria for bladder cancer diagnosis and grading.Prospectively, 73 patients scheduled for transurethral resection of bladder tumour(s) were included. CLE imaging was performed intraoperatively prior to en bloc resection. Histopathology was the reference standard for comparison.Cystoscopic CLE imaging.Three independent observers evaluated the CLE images to classify tumours as low- or high-grade urothelial carcinoma (UC), or benign lesions. Interobserver agreement was calculated with Fleiss kappa analysis and diagnostic accuracy with 2×2 tables.Histopathology of 66 lesions (53 patients) revealed 25 low-grade UCs, 27 high-grade UCs, and 14 benign lesions. For low-grade UC, most common features were papillary configuration (100%), distinct cell borders (81%), presence of fibrovascular stalks (79%), cohesiveness of cells (77%), organised cell pattern (76%), and monomorphic cells (67%). A concordance between CLE-based classification and histopathology was found in 19 cases (76%). For high-grade UC, pleomorphic cells (77%), indistinct cell borders (77%), papillary configuration (67%), and disorganised cell pattern (60%) were the most common features. A concordance with histopathology was found in 19 cases (70%). In benign lesions, the most prevalent features were disorganised cell pattern (57%) and pleomorphic cells (52%), and a concordance with histopathology was found in four cases (29%).The CLE criteria enable identification of UC. CLE features correlate to histopathologic features that may enable real-time tumour grading. However, flat lesions remain difficult to classify.Confocal laser endomicroscopy may enable real-time cancer differentiation during cystoscopy, which is important for prognosis and disease management.
View details for PubMedID 30033066
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Simple and Precise Counting of Viable Bacteria by Resazurin-Amplified Picoarray Detection.
Analytical chemistry
2018
Abstract
Simple, fast, and precise counting of viable bacteria is fundamental to a variety of microbiological applications such as food quality monitoring and clinical diagnosis. To this end, agar plating, microscopy, and emerging microfluidic devices for single bacteria detection have provided useful means for counting viable bacteria, but they also have their limitations ranging from complexity, time, and inaccuracy. We present herein our new method RAPiD (Resazurin-Amplified Picoarray Detection) for addressing this important problem. In RAPiD, we employ vacuum-assisted sample loading and oil-driven sample digitization to stochastically confine single bacteria in Picoarray, a microfluidic device with picoliter-sized isolation chambers (picochambers), in <30 s with only a few minutes of hands-on time. We add AlamarBlue, a resazurin-based fluorescent dye for bacterial growth, in our assay to accelerate the detection of "microcolonies" proliferated from single bacteria within picochambers. Detecting fluorescence in picochambers as an amplified surrogate for bacterial cells allows us to count hundreds of microcolonies with a single image taken via wide-field fluorescence microscopy. We have also expanded our method to practically test multiple titrations from a single bacterial sample in parallel. Using this expanded "multi-RAPiD" strategy, we can quantify viable cells in E. coli and S. aureus samples with precision in ∼3 h, illustrating RAPiD as a promising new method for counting viable bacteria for microbiological applications.
View details for PubMedID 29969556
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A MICROFILTRATION DEVICE FOR DIAGNOSIS OF UROGENITAL SCHISTOSOMIASIS
AMER SOC TROP MED & HYGIENE. 2017: 384
View details for Web of Science ID 000412851502747
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3D reconstruction of cystoscopy videos for comprehensive bladder records
BIOMEDICAL OPTICS EXPRESS
2017; 8 (4): 2106-2123
Abstract
White light endoscopy is widely used for diagnostic imaging of the interior of organs and body cavities, but the inability to correlate individual 2D images with 3D organ morphology limits its utility for quantitative or longitudinal studies of disease physiology or cancer surveillance. As a result, most endoscopy videos, which carry enormous data potential, are used only for real-time guidance and are discarded after collection. We present a computational method to reconstruct and visualize a 3D model of organs from an endoscopic video that captures the shape and surface appearance of the organ. A key aspect of our strategy is the use of advanced computer vision techniques and unmodified, clinical-grade endoscopy hardware with few constraints on the image acquisition protocol, which presents a low barrier to clinical translation. We validate the accuracy and robustness of our reconstruction and co-registration method using cystoscopy videos from tissue-mimicking bladder phantoms and show clinical utility during cystoscopy in the operating room for bladder cancer evaluation. As our method can powerfully augment the visual medical record of the appearance of internal organs, it is broadly applicable to endoscopy and represents a significant advance in cancer surveillance opportunities for big-data cancer research.
View details for DOI 10.1364/BOE.8.002106
View details for Web of Science ID 000400499300007
View details for PubMedCentralID PMC5516821
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3D reconstruction of cystoscopy videos for comprehensive bladder records.
Biomedical optics express
2017; 8 (4): 2106-2123
Abstract
White light endoscopy is widely used for diagnostic imaging of the interior of organs and body cavities, but the inability to correlate individual 2D images with 3D organ morphology limits its utility for quantitative or longitudinal studies of disease physiology or cancer surveillance. As a result, most endoscopy videos, which carry enormous data potential, are used only for real-time guidance and are discarded after collection. We present a computational method to reconstruct and visualize a 3D model of organs from an endoscopic video that captures the shape and surface appearance of the organ. A key aspect of our strategy is the use of advanced computer vision techniques and unmodified, clinical-grade endoscopy hardware with few constraints on the image acquisition protocol, which presents a low barrier to clinical translation. We validate the accuracy and robustness of our reconstruction and co-registration method using cystoscopy videos from tissue-mimicking bladder phantoms and show clinical utility during cystoscopy in the operating room for bladder cancer evaluation. As our method can powerfully augment the visual medical record of the appearance of internal organs, it is broadly applicable to endoscopy and represents a significant advance in cancer surveillance opportunities for big-data cancer research.
View details for DOI 10.1364/BOE.8.002106
View details for PubMedID 28736658
View details for PubMedCentralID PMC5516821
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Integrated Biosensor Assay for Rapid Uropathogen Identification and Phenotypic Antimicrobial Susceptibility Testing.
European urology focus
2017; 3 (2-3): 293–99
Abstract
BACKGROUND: Standard diagnosis of urinary tract infection (UTI) via urine culture for pathogen identification (ID) and antimicrobial susceptibility testing (AST) takes 2-3 d. This delay results in empiric treatment and contributes to the misuse of antibiotics and the rise of resistant pathogens. A rapid diagnostic test for UTI may improve patient care and antibiotic stewardship.OBJECTIVE: To develop and validate an integrated biosensor assay for UTI diagnosis, including pathogen ID and AST, with determination of the minimum inhibitory concentration (MIC) for ciprofloxacin.DESIGN, SETTING, AND PARTICIPANTS: Urine samples positive for Enterobacteriaceae (n=84) or culture-negative (n=23) were obtained from the Stanford Clinical Microbiology Laboratory between November 2013 and September 2014. Each sample was diluted and cultured for 5h with and without ciprofloxacin, followed by quantitative detection of bacterial 16S rRNA using a single electrochemical biosensor array functionalized with a panel of complementary DNA probes. Pathogen ID was determined using universal bacterial, Enterobacteriaceae (EB), and pathogen-specific probes. Phenotypic AST with ciprofloxacin MIC was determined using an EB probe to measure 16S rRNA levels as a function of bacterial growth.MEASUREMENTS: Electrochemical signals for pathogen ID at 6 SD over background were considered positive. An MIC signal of 0.4 log units lower than the no-antibiotic control indicated sensitivity. Results were compared to clinical microbiology reports.RESULTS AND LIMITATIONS: For pathogen ID, the assay had 98.5% sensitivity, 96.6% specificity, 93.0% positive predictive value, and 99.3% negative predictive value. For ciprofloxacin MIC the categorical and essential agreement was 97.6%. Further automation, testing of additional pathogens and antibiotics, and a full prospective study will be necessary for translation to clinical use.CONCLUSIONS: The integrated biosensor platform achieved microbiological results including MIC comparable to standard culture in a significantly shorter assay time. Further assay automation will allow clinical translation for rapid molecular diagnosis of UTI.PATIENT SUMMARY: We have developed and validated a biosensor test for rapid diagnosis of urinary tract infections. Clinical translation of this device has the potential to significantly expedite and improve treatment of urinary tract infections.
View details for PubMedID 28753748
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Deep Sequencing of Urinary RNAs for Bladder Cancer Molecular Diagnostics.
Clinical cancer research : an official journal of the American Association for Cancer Research
2017
Abstract
The majority of bladder cancer patients present with localized disease and are managed by transurethral resection. However, the high rate of recurrence necessitates lifetime cystoscopic surveillance. Developing a sensitive and specific urine-based test would significantly improve bladder cancer screening, detection, and surveillance.RNA-seq was used for biomarker discovery to directly assess the gene expression profile of exfoliated urothelial cells in urine derived from bladder cancer patients (n=13) and controls (n=10). Eight bladder cancer specific and 3 reference genes identified by RNA-seq were quantitated by qPCR in a training cohort of 102 urine samples. A diagnostic model based on the training cohort was constructed using multiple logistic regression. The model was further validated in an independent cohort of 101 urines.418 genes were found to be differentially expressed between bladder cancer and controls. Validation of a subset of these genes was used to construct an equation for computing a probability of bladder cancer score (PBC) based on expression of 3-markers (ROBO1, WNT5A, and CDC42BPB). Setting PBC=0.45 as the cutoff for a positive test, urine testing using the 3-marker panel had overall 88% sensitivity and 92% specificity in the training cohort. The accuracy of the 3-marker panel in the independent validation cohort yielded an area under the curve of 0.87 and overall 83% sensitivity and 89% specificity.Urine-based molecular diagnostics using this 3-marker signature could provide a valuable adjunct to cystoscopy and may lead to a reduction of unnecessary procedures for bladder cancer diagnosis.
View details for DOI 10.1158/1078-0432.CCR-16-2610
View details for PubMedID 28193625
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Accelerating bacterial growth detection and antimicrobial susceptibility assessment in integrated picoliter droplet platform.
Biosensors & bioelectronics
2017; 97: 260–66
Abstract
There remains an urgent need for rapid diagnostic methods that can evaluate antibiotic resistance for pathogenic bacteria in order to deliver targeted antibiotic treatments. Toward this end, we present a rapid and integrated single-cell biosensing platform, termed dropFAST, for bacterial growth detection and antimicrobial susceptibility assessment. DropFAST utilizes a rapid resazurin-based fluorescent growth assay coupled with stochastic confinement of bacteria in 20 pL droplets to detect signal from growing bacteria after 1h incubation, equivalent to 2-3 bacterial replications. Full integration of droplet generation, incubation, and detection into a single, uninterrupted stream also renders this platform uniquely suitable for in-line bacterial phenotypic growth assessment. To illustrate the concept of rapid digital antimicrobial susceptibility assessment, we employ the dropFAST platform to evaluate the antibacterial effect of gentamicin on E. coli growth.
View details for PubMedID 28609716
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Image-guided urologic surgery: intraoperative optical imaging and tissue interrogation (Conference Presentation)
SPIE-INT SOC OPTICAL ENGINEERING. 2017
View details for DOI 10.1117/12.2257640
View details for Web of Science ID 000406427900018
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Image-Guided Transurethral Resection of Bladder Tumors - Current Practice and Future Outlooks
BLADDER CANCER
2017; 3 (3): 149–59
View details for DOI 10.3233/BLC-170119
View details for Web of Science ID 000441720200004
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Development of a 90-minute integrated non-invasive urinary assay for bladder cancer detection.
The Journal of urology
2017
Abstract
Despite suboptimal sensitivity, urine cytology is often performed as an adjunct to cystoscopy for bladder cancer diagnosis. We aimed to develop a non-invasive, fast molecular diagnostic test for bladder cancer detection with better sensitivity than urine cytology while maintaining adequate specificity.Urine specimens were collected at 18 multinational sites from subjects prior to cystoscopy or tumor resection, and from healthy and other control subjects without evidence of bladder cancer. The levels of ten urinary mRNAs were measured in a training cohort (n=483) and regression analysis was used to identify a five mRNA model to predict cancer status. Performance of the investigational use only-labeled GeneXpert® (Cepheid, Sunnyvale, CA) Bladder Cancer Assay, an assay for detection of the five mRNAs (ABL1, CRH, IGF2, ANXA10, and UPK1B), was evaluated in an independent test cohort (n=450).In the independent test cohort, the GeneXpert assay ROC curve AUC was 0.87 (95% CI: 0.81-0.92). At an example cut point of 0.4, the overall sensitivity was 73%, and the specificity was 90% and 77% for hematuria and surveillance patient populations, respectively.We have developed a 90 minute, simple to perform urine-based test for the detection of bladder cancer that can that can help guide physician decision making in the management of bladder cancer. Additional evaluation in a prospective study is needed to establish clinical utility of this assay.
View details for PubMedID 29061538
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Redefining the Stone Belt: Precipitation is Associated with Increased Risk of Urinary Stone Disease.
Journal of endourology
2017
Abstract
Objectives The American Southeast has been labeled the "Stone Belt" due to its relatively high burden of urinary stone disease, presumed to be related to its higher temperatures. However, other regions with high temperatures (e.g. the Southwest) do not have the same disease prevalence as the southeast. We seek to explore the association of stone disease to other climate-associated factors beyond temperature including precipitation and temperature variation.We identified all patients who underwent a surgical procedure for urinary stone disease from the California Office of Statewide Health Planning and Development (OSHPD) databases (2010-2012). Climate data obtained from the National Oceanic and Atmospheric Administration was compared to population adjusted county operative stone burden, controlling for patient and county demographic data as potential confounders.A total of 63,994 unique patients underwent stone procedures in California between 2010-2012. Multivariate modeling revealed higher precipitation (0.019 average increase in surgeries per 1000 persons per inch, p<0.01) and higher mean temperature (0.029 average increase in surgeries per 1000 persons per degree, p<0.01) were both independently associated with an increased operative stone disease burden. Controlling for county level patient factors did not change these observed effects. Conclusion In the state of California, higher precipitation and higher mean temperature are associated with increased rates of stone surgery. Our results appear to agree with the larger trends seen throughout the United States where the areas of highest stone prevalence have warm wet climates, and not warm arid, climates.
View details for PubMedID 28830242
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In vivo biodistribution and toxicity of intravesical administration of quantum dots for optical molecular imaging of bladder cancer.
Scientific reports
2017; 7 (1): 9309
Abstract
Optical molecular imaging holds the potential to improve cancer diagnosis. Fluorescent nanoparticles such as quantum dots (QD) offer superior optical characteristics compared to organic dyes, but their in vivo application is limited by potential toxicity from systemic administration. Topical administration provides an attractive route for targeted nanoparticles with the possibility of minimizing exposure and reduced dose. Previously, we demonstrated successful ex vivo endoscopic imaging of human bladder cancer by topical (i.e. intravesical) administration of QD-conjugated anti-CD47. Herein we investigate in vivo biodistribution and toxicity of intravesically instilled free QD and anti-CD47-QD in mice. In vivo biodistribution of anti-CD47-QD was assessed with inductively coupled plasma mass spectrometry. Local and systemic toxicity was assessed using blood tests, organ weights, and histology. On average, there was no significant accumulation of QD outside of the bladder, although in some mice we detected extravesical biodistribution of QD suggesting a route for systemic exposure under some conditions. There were no indications of acute toxicity up to 7 days after instillation. Intravesical administration of targeted nanoparticles can reduce systemic exposure, but for clinical use, nanoparticles with established biosafety profiles should be used to decrease long-term toxicity in cases where systemic exposure occurs.
View details for PubMedID 28839158
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Image-Guided Transurethral Resection of Bladder Tumors - Current Practice and Future Outlooks.
Bladder cancer (Amsterdam, Netherlands)
2017; 3 (3): 149–59
Abstract
Transurethral resection of bladder tumor (TURBT) under white light cystoscopy (WLC) is the cornerstone for the diagnosis, removal and local staging of non-muscle invasive bladder cancer (NMIBC). Despite technological improvements over the decades, significant shortcomings remain with WLC for tumor detection, thereby impacting the surgical quality and contributing to tumor recurrence and progression. Enhanced cystoscopy modalities such as blue light cystoscopy (BLC) and narrow band imaging (NBI) aid resections by highlighting tumors that might be missed on WLC. Optical biopsy technologies such as confocal laser endomicroscopy (CLE) and optical coherence tomography (OCT) characterize tissue in real-time to ensure a more thorough resection. New resection techniques, particularly en bloc resection, are actively under investigation to improve the overall quality of resections and aid pathologic interpretation. Moreover, new image processing computer algorithms may improve perioperative planning and longitudinal follow-up. Clinical translation of molecular imaging agents is also on the horizon to improve optical diagnosis of bladder cancer. This review focuses on emerging technologies that can impact the quality of TURBT to improve the overall management of NMIBC.
View details for PubMedID 28824942
View details for PubMedCentralID PMC5545914
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Proceedings of the 3rd Annual Albert Institute for Bladder Cancer Research Symposium.
Bladder cancer (Amsterdam, Netherlands)
2017; 3 (3): 211–23
Abstract
The Third Annual Albert Institute Bladder Symposium was held on September 8-10th, 2016, in Denver Colorado. Participants discussed several critical topics in the field of bladder cancer: 1) Best practices for tissue analysis and use to optimize correlative studies, 2) Modeling bladder cancer to facilitate understanding and innovation, 3) Targeted therapies for bladder cancer, 4) Tumor phylogeny in bladder cancer, 5) New Innovations in bladder cancer diagnostics. Our understanding of and approach to treating urothelial carcinoma is undergoing rapid advancement. Preclinical models of bladder cancer have been leveraged to increase our basic and mechanistic understanding of the disease. With the approval of immune checkpoint inhibitors for the treatment of advanced urothelial carcinoma, the treatment approach for these patients has quickly changed. In this light, molecularly-defined subtypes of bladder cancer and appropriate pre-clinical models are now essential to the further advancement and appropriate application of these therapeutic improvements. The optimal collection and processing of clinical urothelial carcinoma tissues samples will also be critical in the development of predictive biomarkers for therapeutic selection. Technological advances in other areas including optimal imaging technologies and micro/nanotechnologies are being applied to bladder cancer, especially in the localized setting, and hold the potential for translational impact in the treatment of bladder cancer patients. Taken together, advances in several basic science and clinical areas are now converging in bladder cancer. These developments hold the promise of shaping and improving the clinical care of those with the disease.
View details for PubMedID 28824949
View details for PubMedCentralID PMC5545918
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Oncologic Procedures Amenable to Fluorescence-guided Surgery.
Annals of surgery
2016
Abstract
Although fluorescence imaging is being applied to a wide range of cancers, it remains unclear which disease populations will benefit greatest. Therefore, we review the potential of this technology to improve outcomes in surgical oncology with attention to the various surgical procedures while exploring trial endpoints that may be optimal for each tumor type.For many tumors, primary treatment is surgical resection with negative margins, which corresponds to improved survival and a reduction in subsequent adjuvant therapies. Despite unfavorable effect on patient outcomes, margin positivity rate has not changed significantly over the years. Thus, patients often experience high rates of re-excision, radical resections, and overtreatment. However, fluorescence-guided surgery (FGS) has brought forth new light by allowing detection of subclinical disease not readily visible with the naked eye.We performed a systematic review of clinicatrials.gov using search terms "fluorescence," "image-guided surgery," and "near-infrared imaging" to identify trials utilizing FGS for those received on or before May 2016.fluorescence surgery for tumor debulking, wide local excision, whole-organ resection, and peritoneal metastases.fluorescence in situ hybridization, fluorescence imaging for lymph node mapping, nonmalignant lesions, nonsurgical purposes, or image guidance without fluorescence.Initial search produced 844 entries, which was narrowed down to 68 trials. Review of literature and clinical trials identified 3 primary resection methods for utilizing FGS: (1) debulking, (2) wide local excision, and (3) whole organ excision.The use of FGS as a surgical guide enhancement has the potential to improve survival and quality of life outcomes for patients. And, as the number of clinical trials rise each year, it is apparent that FGS has great potential for a broad range of clinical applications.
View details for DOI 10.1097/SLA.0000000000002127
View details for PubMedID 28045715
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Registration of free-hand OCT daughter endoscopy to 3D organ reconstruction
BIOMEDICAL OPTICS EXPRESS
2016; 7 (12): 4995-5009
Abstract
Despite the trend to pair white light endoscopy with secondary image modalities for in vivo characterization of suspicious lesions, challenges remain to co-register such data. We present an algorithm to co-register two different optical imaging modalities as a mother-daughter endoscopy pair. Using white light cystoscopy (mother) and optical coherence tomography (OCT) (daughter) as an example, we developed the first forward-viewing OCT endoscope that fits in the working channel of flexible cystoscopes and demonstrated our algorithm's performance with optical phantom and clinical imaging data. The ability to register multimodal data opens opportunities for advanced analysis in cancer imaging applications.
View details for DOI 10.1364/BOE.7.004995
View details for Web of Science ID 000390490700013
View details for PubMedID 28018720
View details for PubMedCentralID PMC5175547
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Long-range electrothermal fluid motion in microfluidic systems
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
2016; 98: 341-349
Abstract
AC electrothermal flow (ACEF) is the fluid motion created as a result of Joule heating induced temperature gradients. ACEF is capable of performing major microfluidic operations, such as pumping, mixing, concentration, separation and assay enhancement, and is effective in biological samples with a wide range of electrical conductivity. Here, we report long-range fluid motion induced by ACEF, which creates centimeter-scale vortices. The long-range fluid motion displays a strong voltage dependence and is suppressed in microchannels with a characteristic length below ~300 μm. An extended computational model of ACEF, which considers the effects of the density gradient and temperature-dependent parameters, is developed and compared experimentally by particle image velocimetry. The model captures the essence of ACEF in a wide range of channel dimensions and operating conditions. The combined experimental and computational study reveals the essential roles of buoyancy, temperature rise, and associated changes in material properties in the formation of the long-range fluid motion. Our results provide critical information for the design and modeling of ACEF based microfluidic systems toward various bioanalytical applications.
View details for DOI 10.1016/j.ijheatmasstransfer.2016.03.034
View details for Web of Science ID 000375360600032
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Long-range electrothermal fluid motion in microfluidic systems.
International journal of heat and mass transfer
2016; 98: 341-349
Abstract
AC electrothermal flow (ACEF) is the fluid motion created as a result of Joule heating induced temperature gradients. ACEF is capable of performing major microfluidic operations, such as pumping, mixing, concentration, separation and assay enhancement, and is effective in biological samples with a wide range of electrical conductivity. Here, we report long-range fluid motion induced by ACEF, which creates centimeter-scale vortices. The long-range fluid motion displays a strong voltage dependence and is suppressed in microchannels with a characteristic length below ~300 μm. An extended computational model of ACEF, which considers the effects of the density gradient and temperature-dependent parameters, is developed and compared experimentally by particle image velocimetry. The model captures the essence of ACEF in a wide range of channel dimensions and operating conditions. The combined experimental and computational study reveals the essential roles of buoyancy, temperature rise, and associated changes in material properties in the formation of the long-range fluid motion. Our results provide critical information for the design and modeling of ACEF based microfluidic systems toward various bioanalytical applications.
View details for DOI 10.1016/j.ijheatmasstransfer.2016.03.034
View details for PubMedID 27127306
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Editorial Comment.
journal of urology
2016; 195 (6): 1703-?
View details for DOI 10.1016/j.juro.2016.01.126
View details for PubMedID 27001638
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Editorial Comment.
journal of urology
2016; 195 (5): 1585-?
View details for DOI 10.1016/j.juro.2015.12.114
View details for PubMedID 26900046
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A Multiplex Electrochemical Biosensor for Bloodstream Infection Diagnosis.
Journal of laboratory automation
2016: 2211068216651232-?
Abstract
Accurate and timely detection of bacterial pathogens will improve the clinical management of infections. Herein, we demonstrate an electrochemical biosensor that directly detects bacteria in human blood samples, resulting in the rapid diagnosis of a bloodstream infection. The multiplex biosensor detects the species-specific sequences of the 16S ribosomal RNA of bacteria for pathogen identification in physiological samples without preamplification. The analytical performance characteristics of the biosensor, including the limit of detection and probe cross-reactivity, are evaluated systematically. The feasibility of the biosensor for a diagnosis of a bloodstream infection is demonstrated by identifying bacterial clinical isolates spiked in whole blood and blood culture samples that were tested positive for bacteria. The electrochemical biosensor correctly identifies all the species in the samples with 100% concordance to microbiological analysis.
View details for DOI 10.1177/2211068216651232
View details for PubMedID 27226118
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A Microfiltration Device for Urogenital Schistosomiasis Diagnostics
PLOS ONE
2016; 11 (4)
Abstract
Schistosomiasis is a parasitic disease affecting over 200 million people worldwide. This study reports the design and development of a microfiltration device for isolating schistosome eggs in urine for rapid diagnostics of urogenital schistosomiasis. The design of the device comprises a linear array of microfluidic traps to immobilize and separate schistosome eggs. Sequential loading of individual eggs is achieved autonomously by flow resistance, which facilitates observation and enumeration of samples with low-abundance targets. Computational fluid dynamics modeling and experimental characterization are performed to optimize the trapping performance. By optimizing the capture strategy, the trapping efficiency could be achieved at 100% with 300 μl/min and 83% with 3000 μl/min, and the filtration procedure could be finished within 10 min. The trapped eggs can be either recovered for downstream analysis or preserved in situ for whole-mount staining. On-chip phenotyping using confocal laser fluorescence microscopy identifies the microstructure of the trapped schistosome eggs. The device provides a novel microfluidic approach for trapping, counting and on-chip fluorescence characterization of urinal Schistosoma haematobium eggs for clinical and investigative application.
View details for DOI 10.1371/journal.pone.0154640
View details for Web of Science ID 000375211700119
View details for PubMedID 27124499
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Intraoperative Optical Biopsy during Robotic Assisted Radical Prostatectomy Using Confocal Endomicroscopy
JOURNAL OF UROLOGY
2016; 195 (4): 1110-1117
Abstract
Intraoperative optical biopsy technologies may aid identification of important anatomic landmarks and improve surgical outcomes of robotic-assisted radical prostatectomy (RARP). We sought to evaluate the feasibility of confocal laser endomicroscopy (CLE) during RARP.Twenty-one patients with biopsy-proven prostate cancer scheduled for RARP were recruited. After intravenous administration of fluorescein, 15 patients underwent in vivo intraoperative CLE of prostatic and periprostatic structures using either a 2.6-mm or 0.85-mm imaging probe. Standard robotic instruments were used to grasp and maneuver the CLE probes for image acquisition. CLE imaging was performed ex vivo on fresh prostate specimens from 20 patients. Confocal video sequences acquired in vivo and ex vivo were reviewed and analyzed, with additional image processing using a mosaicing algorithm. Processed confocal images were compared with standard hematoxylin and eosin analysis of imaged regions.CLE was successfully integrated with robotic surgery, including co-registration of confocal video sequences with white light and probe handling with standard robotic instrumentation. Intraoperative CLE imaging of the neurovascular bundle prior to and following nerve-sparing dissection revealed characteristic features including dynamic vascular flow and intact axon fibers. Ex vivo confocal imaging of the prostatic parenchyma demonstrated the normal prostatic glands, stroma, and prostate carcinoma.We report the initial feasibility of optical biopsy of prostatic and periprostatic tissue during RARP. Image guidance and tissue interrogation using CLE offers a new intraoperative imaging method that has the potential to improve the functional and oncologic outcomes of prostate cancer surgery.
View details for DOI 10.1016/j.juro.2015.10.182
View details for Web of Science ID 000373401200108
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Fiber-Optic Confocal Laser Endomicroscopy of Small Renal Masses: Toward Real-Time Optical Diagnostic Biopsy
JOURNAL OF UROLOGY
2016; 195 (2): 486-492
Abstract
The incidental detection of small renal masses is on the rise. However, not all require aggressive treatments as up to 20% are benign and the majority of malignant tumors harbor indolent features. Improved preoperative diagnostics are needed to differentiate tumors requiring aggressive treatment from those more suitable for surveillance. We evaluated and compared confocal laser endomicroscopy (CLE) with standard histopathology in ex vivo human kidney tumors as a proof-of-principle towards diagnostic optical biopsy.Patients with solitary small renal masses scheduled for partial or radical nephrectomy were enrolled in the study. Two kidneys were infused with fluorescein via intraoperative intravenous injection, and 18 tumors were bathed ex vivo in dilute fluorescein prior to confocal imaging. A 2.6 mm CLE probe was used to image tumors and surrounding parenchyma from external and en face surfaces after specimen bisection. CLE images were compared to standard H&E analysis of corresponding areas.Ex vivo CLE imaging revealed normal renal structures that correlated well with histology. Tumor tissue was readily distinguishable from normal parenchyma, demonstrating features unique to benign and malignant tumor subtypes. Topical fluorescein administration provided more consistent CLE imaging than the intravenous route. Additionally, en face tumor imaging was superior to external imaging.We report the first feasibility study using CLE to evaluate small renal masses ex vivo and provide a preliminary atlas of images from various renal neoplasms with corresponding histology. These findings serve as an initial and promising step towards real-time, diagnostic optical biopsy of small renal masses.
View details for DOI 10.1016/j.juro.2015.07.115
View details for PubMedID 26321408
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Multimodal 3D cancer-mimicking optical phantom
BIOMEDICAL OPTICS EXPRESS
2016; 7 (2): 648-662
Abstract
Three-dimensional (3D) organ-mimicking phantoms provide realistic imaging environments for testing various aspects of optical systems, including for evaluating new probe designs, characterizing the diagnostic potential of new technologies, and assessing novel image processing algorithms prior to validation in real tissue. We introduce and characterize the use of a new material, Dragon Skin (Smooth-On Inc.), and fabrication technique, air-brushing, for fabrication of a 3D phantom that mimics the appearance of a real organ under multiple imaging modalities. We demonstrate the utility of the material and technique by fabricating the first 3D, hollow bladder phantom with realistic normal and multi-stage pathology features suitable for endoscopic detection using the gold standard imaging technique, white light cystoscopy (WLC), as well as the complementary imaging modalities of optical coherence tomography and blue light cystoscopy, which are aimed at improving the sensitivity and specificity of WLC to bladder cancer detection. The flexibility of the material and technique used for phantom construction allowed for the representation of a wide range of diseased tissue states, ranging from inflammation (benign) to high-grade cancerous lesions. Such phantoms can serve as important tools for trainee education and evaluation of new endoscopic instrumentation.
View details for DOI 10.1364/BOE.7.000648
View details for Web of Science ID 000369247000034
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Multimodal 3D cancer-mimicking optical phantom.
Biomedical optics express
2016; 7 (2): 648-62
Abstract
Three-dimensional (3D) organ-mimicking phantoms provide realistic imaging environments for testing various aspects of optical systems, including for evaluating new probe designs, characterizing the diagnostic potential of new technologies, and assessing novel image processing algorithms prior to validation in real tissue. We introduce and characterize the use of a new material, Dragon Skin (Smooth-On Inc.), and fabrication technique, air-brushing, for fabrication of a 3D phantom that mimics the appearance of a real organ under multiple imaging modalities. We demonstrate the utility of the material and technique by fabricating the first 3D, hollow bladder phantom with realistic normal and multi-stage pathology features suitable for endoscopic detection using the gold standard imaging technique, white light cystoscopy (WLC), as well as the complementary imaging modalities of optical coherence tomography and blue light cystoscopy, which are aimed at improving the sensitivity and specificity of WLC to bladder cancer detection. The flexibility of the material and technique used for phantom construction allowed for the representation of a wide range of diseased tissue states, ranging from inflammation (benign) to high-grade cancerous lesions. Such phantoms can serve as important tools for trainee education and evaluation of new endoscopic instrumentation.
View details for DOI 10.1364/BOE.7.000648
View details for PubMedID 26977369
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Optical Biopsy of Bladder Cancer Using Crowd-Sourced Assessment.
JAMA surgery
2016; 151 (1): 90-93
View details for DOI 10.1001/jamasurg.2015.3121
View details for PubMedID 26422334
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ULTRA-THIN ELASTOMER MEMBRANE ARRAY WRINKLING FOR BLADDER CANCER DIAGNOSIS
IEEE. 2016: 419–22
View details for Web of Science ID 000381797300110
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Multimodal, 3D pathology-mimicking bladder phantom for evaluation of cystoscopic technologies
SPIE-INT SOC OPTICAL ENGINEERING. 2016
View details for DOI 10.1117/12.2213242
View details for Web of Science ID 000377396200037
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Virtual 3D bladder reconstruction for augmented medical records from white light cystoscopy
SPIE-INT SOC OPTICAL ENGINEERING. 2016
View details for DOI 10.1117/12.2213050
View details for Web of Science ID 000377396200044
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Ultra-thin elastomer membrane array wrinkling for bladder cancer diagnosis
IEEE 29th International Conference on Micro Electro Mechanical Systems (MEMS)
2016: 419
View details for DOI 10.1109/MEMSYS.2016.7421650
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Successful Translation of Fluorescence Navigation During Oncologic Surgery: A Consensus Report
JOURNAL OF NUCLEAR MEDICINE
2016; 57 (1): 144-150
Abstract
Navigation with fluorescence guidance has emerged in the last decade as a promising strategy to improve the efficacy of oncologic surgery. To achieve routine clinical use, the onus is on the surgical community to objectively assess the value of this technique. This assessment may facilitate both the Food and Drug Administration (FDA) approval of new optical imaging agents and reimbursement for the imaging procedures. It is critical to characterize fluorescence-guided procedural benefits over existing practices and to elucidate both the costs and safety risks. This report is the result of a meeting of the International Society of Image Guided Surgery (ISIGS, www.isigs.org) on February 6th, 2015 in Miami, Florida and reflects a consensus of the participants' opinions. Our objective is to critically evaluate the imaging platform technology and optical imaging agents, and to make recommendations for successful clinical trial development of this highly promising approach in oncologic surgery.
View details for DOI 10.2967/jnumed.115.158915
View details for Web of Science ID 000367862700025
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Rapid bladder cancer cell detection from clinical urine samples using an ultra-thin silicone membrane
ANALYST
2016; 141 (2): 652-660
Abstract
Early detection of initial onset, as well as recurrence, of cancer is paramount for improved patient prognosis and human health. Cancer screening is enhanced by rapid differentiation of cancerous from non-cancerous cells which employs the inherent differences in biophysical properties. Our preliminary testing demonstrates that cell-line derived bladder cancer cells deform our <30 nm silicone membrane within an hour and induce visually distinct wrinkle patterns while cell-line derived non-cancerous cells fail to induce these wrinkle patterns. Herein, we report a platform for the rapid detection of cancerous cells from human clinical urine samples. We performed a blinded study with cells extracted from the urine of human patients suspected to have bladder cancer alongside healthy controls. Wrinkle patterns were induced specifically by the five cancer patient samples within 12 hours and not by the healthy controls. These results were independently validated by the standard diagnostic techniques cystoscopy and cytology. Thus, our ultra-thin membrane approach for cancer diagnosis appears as accurate as standard diagnostic methods while vastly more rapid, less invasive, and requiring limited expertise.
View details for DOI 10.1039/c5an01616a
View details for Web of Science ID 000368185500026
View details for PubMedID 26549051
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AC Electrokinetics of Physiological Fluids for Biomedical Applications
JALA
2015; 20 (6): 611-620
Abstract
Alternating current (AC) electrokinetics is a collection of processes for manipulating bulk fluid mass and embedded objects with AC electric fields. The ability of AC electrokinetics to implement the major microfluidic operations, such as pumping, mixing, concentration, and separation, makes it possible to develop integrated systems for clinical diagnostics in nontraditional health care settings. The high conductivity of physiological fluids presents new challenges and opportunities for AC electrokinetics-based diagnostic systems. In this review, AC electrokinetic phenomena in conductive physiological fluids are described followed by a review of the basic microfluidic operations and the recent biomedical applications of AC electrokinetics. The future prospects of AC electrokinetics for clinical diagnostics are presented.
View details for DOI 10.1177/2211068214560904
View details for Web of Science ID 000365429900001
View details for PubMedID 25487557
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A Pilot Study of In Vivo Confocal Laser Endomicroscopy of Upper Tract Urothelial Carcinoma
JOURNAL OF ENDOUROLOGY
2015; 29 (12): 1418-1423
Abstract
Tissue diagnosis of upper tract urothelial carcinoma (UTUC) is limited by variance in tumor sampling by standard ureteroscopic biopsy. Optical imaging technologies can potentially improve UTUC diagnosis, surveillance, and endoscopic treatment. We previously demonstrated in vivo optical biopsy of urothelial carcinoma of the bladder using confocal laser endomicroscopy (CLE). In this study, we evaluated a new 0.85-mm imaging probe in the upper urinary tract and demonstrated feasibility and compatibility with standard ureteroscopes to achieve in vivo optical biopsy of UTUC.Fourteen patients scheduled for ureteroscopy of suspected upper tract lesions or surveillance of UTUC were recruited. After intravenous (IV) administration of fluorescein, CLE was performed using a 0.85-mm-diameter imaging probe inserted through the working channel of standard ureteroscopes. Acquired confocal video sequences were reviewed and analyzed. A mosaicing algorithm was used to compile a series of images into a single larger composite image. Processed CLE images were compared with standard histopathologic analysis.Optical biopsy of the UTUC using CLE was effectively achieved during standard ureteroscopy. There were no adverse events related to IV fluorescein administration or image acquisition. Confocal imaging of UTUC showed characteristic features similar to urothelial carcinoma of the bladder, including papillary structure, fibrovascular stalks, and pleomorphism. Lamina propria in normal areas of the renal pelvis and ureter was also identified.We report an initial feasibility of CLE of UTUC. Pending further clinical investigation, CLE may become a useful adjunct to ureteroscopic biopsy, endoscopic ablation, and surveillance of UTUC.
View details for DOI 10.1089/end.2015.0523
View details for Web of Science ID 000366602600015
View details for PubMedID 26413927
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DEVELOPMENT OF A BIOSENSOR-BASED RAPID URINE TEST FOR DETECTION OF UROGENITAL SCHISTOSOMIASIS
AMER SOC TROP MED & HYGIENE. 2015: 562
View details for Web of Science ID 000412844104064
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Optical Biopsy of Peripheral Nerve Using Confocal Laser Endomicroscopy: A New Tool for Nerve Surgeons?
Archives of plastic surgery
2015; 42 (5): 626-629
Abstract
Peripheral nerve injuries remain a challenge for reconstructive surgeons with many patients obtaining suboptimal results. Understanding the level of injury is imperative for successful repair. Current methods for distinguishing healthy from damaged nerve are time consuming and possess limited efficacy. Confocal laser endomicroscopy (CLE) is an emerging optical biopsy technology that enables dynamic, high resolution, sub-surface imaging of live tissue. Porcine sciatic nerve was either left undamaged or briefly clamped to simulate injury. Diluted fluorescein was applied topically to the nerve. CLE imaging was performed by direct contact of the probe with nerve tissue. Images representative of both damaged and undamaged nerve fibers were collected and compared to routine H&E histology. Optical biopsy of undamaged nerve revealed bands of longitudinal nerve fibers, distinct from surrounding adipose and connective tissue. When damaged, these bands appear truncated and terminate in blebs of opacity. H&E staining revealed similar features in damaged nerve fibers. These results prompt development of a protocol for imaging peripheral nerves intraoperatively. To this end, improving surgeons' ability to understand the level of injury through real-time imaging will allow for faster and more informed operative decisions than the current standard permits.
View details for DOI 10.5999/aps.2015.42.5.626
View details for PubMedID 26430636
View details for PubMedCentralID PMC4579176
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Role of Narrow Band Imaging in Management of Urothelial Carcinoma
CURRENT UROLOGY REPORTS
2015; 16 (8)
Abstract
Urothelial carcinoma of the bladder and upper tract is primarily diagnosed by white light endoscopy, which has well-known limitations that contribute to the increased risk of tumor recurrence and progression. Narrow band imaging (NBI) is an optical imaging technology that facilitates detection of tumor vasculature and differentiation of benign urothelium from neoplastic tissue. For urothelial carcinoma, NBI may be utilized in a variety of clinical settings, including office cystoscopy for initial identification and surveillance, transurethral resection for pathological diagnosis, and ureteroscopic management of upper tract lesions. Early evidence suggests that NBI increases the detection of urothelial carcinoma in the bladder and upper tract, including flat high-grade lesions such as carcinoma-in-situ that are a diagnostic challenge under white light. NBI also appears to improve the quality of transurethral resection and thereby reduce the frequency of tumor recurrence.
View details for DOI 10.1007/s11934-015-0527-5
View details for Web of Science ID 000357431600008
View details for PubMedID 26093973
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Advances in Imaging Technologies in the Evaluation of High-Grade Bladder Cancer
UROLOGIC CLINICS OF NORTH AMERICA
2015; 42 (2): 147-?
Abstract
Bladder cancer ranges from a low-grade variant to high-grade disease. Assessment for treatment depends on white light cystoscopy, however because of its limitations there is a need for improved visualization of flat, multifocal, high-grade, and muscle-invasive lesions. Photodynamic diagnosis and narrow-band imaging provide additional contrast enhancement of bladder tumors and have been shown to improve detection rates. Confocal laser endomicroscopy and optical coherence tomography enable real-time, high-resolution, subsurface tissue characterization with spatial resolutions similar to histology. Molecular imaging offers the potential for the combination of optical imaging technologies with cancer-specific molecular agents to improve the specificity of disease detection.
View details for DOI 10.1016/j.ucl.2015.01.001
View details for Web of Science ID 000354588200003
View details for PubMedID 25882557
View details for PubMedCentralID PMC4402158
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OPTICAL BIOPSY OF SUSPECTED PENILE CANCER USING CONFOCAL LASER ENDOMICROSCOPY: INITIAL FEASIBILITY STUDY
ELSEVIER SCIENCE INC. 2015: E327
View details for DOI 10.1016/j.juro.2015.02.1324
View details for Web of Science ID 000362826300116
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MOLECULAR IMAGING OF ORTHOTOPIC MOUSE BLADDER CANCER MODEL USING A CD47 ANTIBODY
ELSEVIER SCIENCE INC. 2015: E559
View details for DOI 10.1016/j.juro.2015.02.1650
View details for Web of Science ID 000362826500017
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Editorial Comment.
The Journal of urology
2015
View details for PubMedID 26542267
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Development of a Biosensor-Based Rapid Urine Test for Detection of Urogenital Schistosomiasis.
PLoS neglected tropical diseases
2015; 9 (7): e0003845
View details for PubMedID 26134995
View details for PubMedCentralID PMC4489877
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Rapid Antimicrobial Susceptibility Testing with Electrokinetics Enhanced Biosensors for Diagnosis of Acute Bacterial Infections
ANNALS OF BIOMEDICAL ENGINEERING
2014; 42 (11): 2314-2321
Abstract
Rapid pathogen detection and antimicrobial susceptibility testing (AST) are required in diagnosis of acute bacterial infections to determine the appropriate antibiotic treatment. Molecular approaches for AST are often based on the detection of known antibiotic resistance genes. Phenotypic culture analysis requires several days from sample collection to result reporting. Toward rapid diagnosis of bacterial infection in non-traditional healthcare settings, we have developed a rapid AST approach that combines phenotypic culture of bacterial pathogens in physiological samples and electrochemical sensing of bacterial 16S rRNA. The assay determines the susceptibility of pathogens by detecting bacterial growth under various antibiotic conditions. AC electrokinetic fluid motion and Joule heating induced temperature elevation are optimized to enhance the sensor signal and minimize the matrix effect, which improve the overall sensitivity of the assay. The electrokinetics enhanced biosensor directly detects the bacterial pathogens in blood culture without prior purification. Rapid determination of the antibiotic resistance profile of Escherichia coli clinical isolates is demonstrated.
View details for DOI 10.1007/s10439-014-1040-6
View details for Web of Science ID 000344091600011
View details for PubMedID 24889716
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Hedgehog Signaling Restrains Bladder Cancer Progression by Eliciting Stromal Production of Urothelial Differentiation Factors
CANCER CELL
2014; 26 (4): 521-533
Abstract
Hedgehog (Hh) pathway inhibitors are clinically effective in treatment of basal cell carcinoma and medulloblastoma, but fail therapeutically or accelerate progression in treatment of endodermally derived colon and pancreatic cancers. In bladder, another organ of endodermal origin, we find that despite its initial presence in the cancer cell of origin Sonic hedgehog (Shh) expression is invariably lost during progression to invasive urothelial carcinoma. Genetic blockade of stromal response to Shh furthermore dramatically accelerates progression and decreases survival time. This cancer-restraining effect of Hh pathway activity is associated with stromal expression of BMP signals, which stimulate urothelial differentiation. Progression is dramatically reduced by pharmacological activation of BMP pathway activity with low-dose FK506, suggesting an approach to management of human bladder cancer.
View details for DOI 10.1016/j.cce11.2014.09.001
View details for Web of Science ID 000343343800012
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Confocal laser endomicroscopy of bladder and upper tract urothelial carcinoma: a new era of optical diagnosis?
Current urology reports
2014; 15 (9): 437-?
Abstract
Urothelial carcinoma of the bladder and upper tract pose significant diagnostic and therapeutic challenges. White light endoscopy plays a central role in the management of urothelial carcinoma but has several well-recognized shortcomings. New optical imaging technologies may improve diagnostic accuracy, enhance local cancer control, and better stratify treatment options. Confocal laser endomicroscopy enables dynamic imaging of the cellular structures below the mucosal surface and holds promise in providing real time optical diagnosis and grading of urothelial carcinoma. A variety of imaging probes are available that are compatible with the full spectrum of cystoscopes and ureteroscopes. We review the underlying principles and technique of confocal laser endomicroscopy in the urinary tract, with emphasis on specific application towards urothelial carcinoma. While the available data are largely related to urothelial carcinoma of the bladder, the lessons learned are directly applicable to the upper tract, where the clinical needs are significant. Ongoing efforts to optimize this technology offer an exciting glimpse into future advances in optical imaging and intraoperative image guidance.
View details for DOI 10.1007/s11934-014-0437-y
View details for PubMedID 25002073
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A Cell Phone-Based Microphotometric System for Rapid Antimicrobial Susceptibility Testing
JALA
2014; 19 (3): 258-266
Abstract
This study demonstrates a low-cost, portable diagnostic system for rapid antimicrobial susceptibility testing in resource-limited settings. To determine the antimicrobial resistance phenotypically, the growth of pathogens in microwell arrays is detected under different antibiotic conditions. The use of a colorimetric cell viability reagent is shown to significantly improve the sensitivity of the assay compared with standard absorbance spectroscopy. Gas-permeable microwell arrays are incorporated for facilitating rapid bacterial growth and eliminating the requirement of bulky supporting equipment. Antibiotics can also be precoated in the microwell array to simplify the assay protocol toward point-of-care applications. Furthermore, a low-cost cell phone-based microphotometric system is developed for detecting the bacterial growth in the microwell array. By optimizing the operating conditions, the system allows antimicrobial susceptibility testing for samples with initial concentrations from 10(1) to 10(6) cfu/mL. Using urinary tract infection as the model system, we demonstrate rapid antimicrobial resistance profiling for uropathogens in both culture media and urine. With its simplicity and cost-effectiveness, the cell phone-based microphotometric system is anticipated to have broad applicability in resource-limited settings toward the management of infectious diseases caused by multidrug-resistant pathogens.
View details for DOI 10.1177/2211068213491095
View details for Web of Science ID 000336267600004
View details for PubMedID 23697894
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Emerging endoscopic imaging technologies for bladder cancer detection.
Current urology reports
2014; 15 (5): 406-?
Abstract
Modern urologic endoscopy is the result of continuous innovations since the early nineteenth century. White-light cystoscopy is the primary strategy for identification, resection, and local staging of bladder cancer. While highly effective, white light cystoscopy has several well-recognized shortcomings. Recent advances in optical imaging technologies and device miniaturization hold the potential to improve bladder cancer diagnosis and resection. Photodynamic diagnosis and narrow band imaging are the first to enter the clinical arena. Confocal laser endomicroscopy, optical coherence tomography, Raman spectroscopy, UV autofluorescence, and others have shown promising clinical and pre-clinical feasibility. We review their mechanisms of action, highlight their respective advantages, and propose future directions.
View details for DOI 10.1007/s11934-014-0406-5
View details for PubMedID 24658832
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OPTICAL BIOPSY OF PROSTATE CANCER THROUGH CONFOCAL LASER ENDOMICROSCOPY
ELSEVIER SCIENCE INC. 2014: E658–E659
View details for DOI 10.1016/j.juro.2014.02.1818
View details for Web of Science ID 000350277902468
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Advances and challenges in biosensor-based diagnosis of infectious diseases.
Expert review of molecular diagnostics
2014; 14 (2): 225-244
Abstract
Rapid diagnosis of infectious diseases and timely initiation of appropriate treatment are critical determinants that promote optimal clinical outcomes and general public health. Conventional in vitro diagnostics for infectious diseases are time-consuming and require centralized laboratories, experienced personnel and bulky equipment. Recent advances in biosensor technologies have potential to deliver point-of-care diagnostics that match or surpass conventional standards in regards to time, accuracy and cost. Broadly classified as either label-free or labeled, modern biosensors exploit micro- and nanofabrication technologies and diverse sensing strategies including optical, electrical and mechanical transducers. Despite clinical need, translation of biosensors from research laboratories to clinical applications has remained limited to a few notable examples, such as the glucose sensor. Challenges to be overcome include sample preparation, matrix effects and system integration. We review the advances of biosensors for infectious disease diagnostics and discuss the critical challenges that need to be overcome in order to implement integrated diagnostic biosensors in real world settings.
View details for DOI 10.1586/14737159.2014.888313
View details for PubMedID 24524681
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Three-dimensional, distendable bladder phantom for optical coherence tomography and white light cystoscopy.
Journal of biomedical optics
2014; 19 (3): 36009-?
Abstract
ABSTRACT. We describe a combination of fabrication techniques and a general process to construct a three-dimensional (3-D) phantom that mimics the size, macroscale structure, microscale surface topology, subsurface microstructure, optical properties, and functional characteristics of a cancerous bladder. The phantom also includes features that are recognizable in white light (i.e., the visual appearance of blood vessels), making it suitable to emulate the bladder for emerging white light+optical coherence tomography (OCT) cystoscopies and other endoscopic procedures of large, irregularly shaped organs. The fabrication process has broad applicability and can be generalized to OCT phantoms for other tissue types or phantoms for other imaging modalities. To this end, we also enumerate the nuances of applying known fabrication techniques (e.g., spin coating) to contexts (e.g., nonplanar, 3-D shapes) that are essential to establish their generalizability and limitations. We anticipate that this phantom will be immediately useful to evaluate innovative OCT systems and software being developed for longitudinal bladder surveillance and early cancer detection.
View details for DOI 10.1117/1.JBO.19.3.036009
View details for PubMedID 24623158
View details for PubMedCentralID PMC3951584
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Intraoperative optical imaging and tissue interrogation during urologic surgery.
Current opinion in urology
2014; 24 (1): 66-74
Abstract
To review optical imaging technologies in urologic surgery aimed to facilitate intraoperative imaging and tissue interrogation.Emerging new optical imaging technologies can be integrated in the operating room environment during minimally invasive and open surgery. These technologies include macroscopic fluorescence imaging that provides contrast enhancement between normal and diseased tissue and microscopic imaging that provides tissue characterization.Optical imaging technologies that have reached the clinical arena in urologic surgery were reviewed, including photodynamic diagnosis, near infrared fluorescence imaging, optical coherence tomography, and confocal laser endomicroscopy.
View details for DOI 10.1097/MOU.0000000000000010
View details for PubMedID 24240512
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WRINKLE CELLOMICS: SCREENING BLADDER CANCER CELLS USING AN ULTRA-THIN SILICONE MEMBRANE
IEEE. 2014: 889–92
View details for Web of Science ID 000352217500227
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Electrokinetic stringency control in self-assembled monolayer-based biosensors for multiplex urinary tract infection diagnosis
NANOMEDICINE-NANOTECHNOLOGY BIOLOGY AND MEDICINE
2014; 10 (1): 159-166
Abstract
Rapid detection of bacterial pathogens is critical toward judicious management of infectious diseases. Herein, we demonstrate an in situ electrokinetic stringency control approach for a self-assembled monolayer-based electrochemical biosensor toward urinary tract infection diagnosis. The in situ electrokinetic stringency control technique generates Joule heating induced temperature rise and electrothermal fluid motion directly on the sensor to improve its performance for detecting bacterial 16S rRNA, a phylogenetic biomarker. The dependence of the hybridization efficiency reveals that in situ electrokinetic stringency control is capable of discriminating single-base mismatches. With electrokinetic stringency control, the background noise due to the matrix effects of clinical urine samples can be reduced by 60%. The applicability of the system is demonstrated by multiplex detection of three uropathogenic clinical isolates with similar 16S rRNA sequences. The results demonstrate that electrokinetic stringency control can significantly improve the signal-to-noise ratio of the biosensor for multiplex urinary tract infection diagnosis.Urinary tract infections remain a significant cause of mortality and morbidity as secondary conditions often related to chronic diseases or to immunosuppression. Rapid and sensitive identification of the causative organisms is critical in the appropriate management of this condition. These investigators demonstrate an in situ electrokinetic stringency control approach for a self-assembled monolayer-based electrochemical biosensor toward urinary tract infection diagnosis, establishing that such an approach significantly improves the biosensor's signal-to-noise ratio.
View details for DOI 10.1016/j.nano.2013.07.006
View details for Web of Science ID 000329103500017
View details for PubMedID 23891989
View details for PubMedCentralID PMC3858494
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A Universal Electrode Approach for Automated Electrochemical Molecular Analyses
JOURNAL OF MICROELECTROMECHANICAL SYSTEMS
2013; 22 (5): 1126-1132
Abstract
Transforming microfluidics-based biosensing systems from laboratory research into clinical reality remains an elusive goal despite decades of intensive research. A fundamental obstacle for the development of fully automated microfluidic diagnostic systems is the lack of an effective strategy for combining pumping, sample preparation, and detection modules into an integrated biosensing platform. Herein, we report a universal electrode approach, which incorporates DC electrolytic pumping, AC electrokinetic sample preparation, and self-assembled monolayer based electrochemical sensing on a single microfluidic platform, to automate complicated molecular analysis procedures that will enable biosensing applications in non-traditional healthcare settings. Using the universal electrode approach, major microfluidic operations required in molecular analyses, such as pumping, mixing, washing, and sensing can be performed in a single platform. We demonstrate the universal electrode platform for detecting bacterial 16S rRNA, a phylogenetic marker, toward rapid diagnostics of urinary tract infection. Since only electronic interfaces are required to operate the platform, the universal electrode approach represents an effective system integration strategy to realize the potential of microfluidics in molecular diagnostics at the point of care.
View details for DOI 10.1109/JMEMS.2013.2253545
View details for Web of Science ID 000325410300020
View details for PubMedCentralID PMC4028488
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A Universal Electrode Approach for Automated Electrochemical Molecular Analyses.
Journal of microelectromechanical systems : a joint IEEE and ASME publication on microstructures, microactuators, microsensors, and microsystems
2013; 22 (5): 1126-1132
Abstract
Transforming microfluidics-based biosensing systems from laboratory research into clinical reality remains an elusive goal despite decades of intensive research. A fundamental obstacle for the development of fully automated microfluidic diagnostic systems is the lack of an effective strategy for combining pumping, sample preparation, and detection modules into an integrated biosensing platform. Herein, we report a universal electrode approach, which incorporates DC electrolytic pumping, AC electrokinetic sample preparation, and self-assembled monolayer based electrochemical sensing on a single microfluidic platform, to automate complicated molecular analysis procedures that will enable biosensing applications in non-traditional healthcare settings. Using the universal electrode approach, major microfluidic operations required in molecular analyses, such as pumping, mixing, washing, and sensing can be performed in a single platform. We demonstrate the universal electrode platform for detecting bacterial 16S rRNA, a phylogenetic marker, toward rapid diagnostics of urinary tract infection. Since only electronic interfaces are required to operate the platform, the universal electrode approach represents an effective system integration strategy to realize the potential of microfluidics in molecular diagnostics at the point of care.
View details for DOI 10.1109/JMEMS.2013.2253545
View details for PubMedID 24860248
View details for PubMedCentralID PMC4028488
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Turning on the lights: new technologies in optical diagnostics and therapeutics.
journal of urology
2013; 190 (2): 381-382
View details for DOI 10.1016/j.juro.2013.05.026
View details for PubMedID 23688641
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Interobserver agreement of confocal laser endomicroscopy for bladder cancer.
Journal of endourology
2013; 27 (5): 598-603
Abstract
Emerging optical imaging technologies such as confocal laser endomicroscopy (CLE) hold promise in improving bladder cancer diagnosis. The purpose of this study was to determine the interobserver agreement of image interpretation using CLE for bladder cancer.Experienced CLE urologists (n=2), novice CLE urologists (n=6), pathologists (n=4), and nonclinical researchers (n=5) were recruited to participate in a 2-hour computer-based training consisting of a teaching and validation set of intraoperative white light cystoscopy (WLC) and CLE video sequences from patients undergoing transurethral resection of bladder tumor. Interobserver agreement was determined using the κ statistic.Of the 31 bladder regions analyzed, 19 were cancer and 12 were benign. For cancer diagnosis, experienced CLE urologists had substantial agreement for both CLE and WLC+CLE (90%, κ 0.80) compared with moderate agreement for WLC alone (74%, κ 0.46), while novice CLE urologists had moderate agreement for CLE (77%, κ 0.55), WLC (78%, κ 0.54), and WLC+CLE (80%, κ 0.59). Pathologists had substantial agreement for CLE (81%, κ 0.61), and nonclinical researchers had moderate agreement (77%, κ 0.49) in cancer diagnosis. For cancer grading, experienced CLE urologists had fair to moderate agreement for CLE (68%, κ 0.64), WLC (74%, κ 0.67), and WLC+CLE (53%, κ 0.33), as did novice CLE urologists for CLE (53%, κ 0.39), WLC (66%, κ 0.50), and WLC+CLE (61%, κ 0.49). Pathologists (65%, κ 0.55) and nonclinical researchers (61%, κ 0.56) both had moderate agreement for CLE in cancer grading.CLE is an adoptable technology for cancer diagnosis in novice CLE observers after a short training with moderate interobserver agreement and diagnostic accuracy similar to WLC alone. Experienced CLE observers may be capable of achieving substantial levels of agreement for cancer diagnosis that is higher than with WLC alone.
View details for DOI 10.1089/end.2012.0549
View details for PubMedID 23072435
View details for PubMedCentralID PMC3643225
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Single Cell Antimicrobial Susceptibility Testing by Confined Microchannels and Electrokinetic Loading
ANALYTICAL CHEMISTRY
2013; 85 (8): 3971-3976
Abstract
Multidrug-resistant pathogens are an emerging global health problem. In addition to the need of developing new antibiotics in the pipeline, the ability to rapidly determine the antibiotic resistance profiles of bacteria represents one of the most crucial steps toward the management of infectious diseases and the prevention of multidrug-resistant pathogens. Here, we report a single cell antimicrobial susceptibility testing (AST) approach for rapid determination of the antibiotic resistance of bacterial pathogens. By confining individual bacteria in gas permeable microchannels with dimensions comparable to a single bacterium, the antibiotic resistance of the bacteria can be monitored in real-time at the single cell level. To facilitate the dynamic loading of the bacteria into the confined microchannels for observation, AC electrokinetics is demonstrated for capturing bacteria to defined locations in high-conductivity AST buffer. The electrokinetic technique achieves a loading efficiency of about 75% with a negligible effect on the bacterial growth rate. To optimize the protocol for single cell AST, the bacterial growth rate of individual bacteria under different antibiotic conditions has been determined systematically. The applicability of single cell AST is demonstrated by the rapid determination of the antimicrobial resistant profiles of uropathogenic clinical isolates in Mueller-Hinton media and in urine. The antibiotic resistance profiles of bacteria can be determined in less than 1 h compared to days in standard culture-based AST techniques.
View details for DOI 10.1021/ac4004248
View details for Web of Science ID 000317794800027
View details for PubMedID 23445209
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Multiplex detection of urinary biomarkers for rapid bladder cancer diagnosis using an automated cartridge-based platform.
AMER ASSOC CANCER RESEARCH. 2013
View details for DOI 10.1158/1538-7445.AM2013-LB-84
View details for Web of Science ID 000331220601331
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Integrated Microfluidic Systems for Molecular Diagnostics A universal electroce platform for rapid diacnosis of urinary tract infections
IEEE NANOTECHNOLOGY MAGAZINE
2013; 7 (1): 31–37
View details for DOI 10.1109/MNANO.2012.2237331
View details for Web of Science ID 000219743800006
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Probe-based confocal laser endomicroscopy of the urinary tract: the technique.
Journal of visualized experiments : JoVE
2013: e4409-?
Abstract
Probe-based confocal laser endomicroscopy (CLE) is an emerging optical imaging technology that enables real-time in vivo microscopy of mucosal surfaces during standard endoscopy. With applications currently in the respiratory and gastrointestinal tracts, CLE has also been explored in the urinary tract for bladder cancer diagnosis. Cellular morphology and tissue microarchitecture can be resolved with micron scale resolution in real time, in addition to dynamic imaging of the normal and pathological vasculature. The probe-based CLE system (Cellvizio, Mauna Kea Technologies, France) consists of a reusable fiberoptic imaging probe coupled to a 488 nm laser scanning unit. The imaging probe is inserted in the working channels of standard flexible and rigid endoscopes. An endoscope-based CLE system (Optiscan, Australia), in which the confocal endomicroscopy functionality is integrated onto the endoscope, is also used in the gastrointestinal tract. Given the larger scope diameter, however, application in the urinary tract is currently limited to ex vivo use. Confocal image acquisition is done through direct contact of the imaging probe with the target tissue and recorded as video sequences. As in the gastrointestinal tract, endomicroscopy of the urinary tract requires an exogenenous contrast agent-most commonly fluorescein, which can be administered intravenously or intravesically. Intravesical administration is a well-established method to introduce pharmacological agents locally with minimal systemic toxicity that is unique to the urinary tract. Fluorescein rapidly stains the extracellular matrix and has an established safety profile. Imaging probes of various diameters enable compatibility with different caliber endoscopes. To date, 1.4 and 2.6 mm probes have been evaluated with flexible and rigid cystoscopy. Recent availability of a < 1 mm imaging probe opens up the possibility of CLE in the upper urinary tract during ureteroscopy. Fluorescence cystoscopy (i.e. photodynamic diagnosis) and narrow band imaging are additional endoscope-based optical imaging modalities that can be combined with CLE to achieve multimodal imaging of the urinary tract. In the future, CLE may be coupled with molecular contrast agents such as fluorescently labeled peptides and antibodies for endoscopic imaging of disease processes with molecular specificity.
View details for DOI 10.3791/4409
View details for PubMedID 23354133
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An AC electrokinetics facilitated biosensor cassette for rapid pathogen identification
ANALYST
2013; 138 (13): 3660-3666
Abstract
To develop a portable point-of-care system based on biosensors for common infectious diseases such as urinary tract infection, the sensing process needs to be implemented within an enclosed fluidic system. On chip sample preparation of clinical samples remains a significant obstacle to achieving robust sensor performance. Herein AC electrokinetics is applied in an electrochemical biosensor cassette to enhance molecular convection and hybridization efficiency through electrokinetics induced fluid motion and Joule heating induced temperature elevation. Using E. coli as an exemplary pathogen, we determined the optimal electrokinetic parameters for detecting bacterial 16S rRNA in the biosensor cassette based on the current output, signal-to-noise ratio, and limit of detection. In addition, a panel of six probe sets targeting common uropathogenic bacteria was demonstrated. The optimized parameters were also validated using patient-derived clinical urine samples. The effectiveness of electrokinetics for on chip sample preparation will facilitate the implementation of point-of-care diagnosis of urinary tract infection in the future.
View details for DOI 10.1039/c3an00259d
View details for Web of Science ID 000319876800012
View details for PubMedID 23626988
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New Optical Imaging Technologies for Bladder Cancer: Considerations and Perspectives
JOURNAL OF UROLOGY
2012; 188 (2): 361-368
Abstract
Bladder cancer presents as a spectrum of different diatheses. Accurate assessment for individualized treatment depends on initial diagnostic accuracy. Detection relies on white light cystoscopy accuracy and comprehensiveness. Aside from invasiveness and potential risks, white light cystoscopy shortcomings include difficult flat lesion detection, precise tumor delineation to enable complete resection, inflammation and malignancy differentiation, and grade and stage determination. Each shortcoming depends on surgeon ability and experience with the technology available for visualization and resection. Fluorescence cystoscopy/photodynamic diagnosis, narrow band imaging, confocal laser endomicroscopy and optical coherence tomography address the limitations and have in vivo feasibility. They detect suspicious lesions (photodynamic diagnosis and narrow band imaging) and further characterize lesions (optical coherence tomography and confocal laser endomicroscopy). We analyzed the added value of each technology beyond white light cystoscopy and evaluated their maturity to alter the cancer course.Detailed PubMed® searches were done using the terms "fluorescence cystoscopy," "photodynamic diagnosis," "narrow band imaging," "optical coherence tomography" and "confocal laser endomicroscopy" with "optical imaging," "bladder cancer" and "urothelial carcinoma." Diagnostic accuracy reports and all prospective studies were selected for analysis. We explored technological principles, preclinical and clinical evidence supporting nonmuscle invasive bladder cancer detection and characterization, and whether improved sensitivity vs specificity translates into improved correlation of diagnostic accuracy with recurrence and progression. Emerging preclinical technologies with potential application were reviewed.Photodynamic diagnosis and narrow band imaging improve nonmuscle invasive bladder cancer detection, including carcinoma in situ. Photodynamic diagnosis identifies more papillary lesions than white light cystoscopy, enabling more complete resection and fewer residual tumors. Despite improved treatment current data on photodynamic diagnosis do not support improved high risk diathetic detection and characterization or correlation with disease progression. Prospective recurrence data are lacking on narrow band imaging. Confocal laser endomicroscopy and optical coherence tomography potentially grade and stage lesions but data are lacking on diagnostic accuracy. Several emerging preclinical technologies may enhance the diagnostic capability of endoscopic imaging.New optical imaging technologies may improve bladder cancer detection and characterization, and transurethral resection quality. While data on photodynamic diagnosis are strongest, the clinical effectiveness of these technologies is not proven. Prospective studies are needed, particularly of narrow band imaging, confocal laser endomicroscopy and optical coherence tomography. As each technology matures and new ones emerge, cost-effectiveness analysis must be addressed in the context of the various bladder cancer types.
View details for DOI 10.1016/j.juro.2012.03.127
View details for Web of Science ID 000306270600006
View details for PubMedID 22698620
View details for PubMedCentralID PMC4035237
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Rapid hybridization of nucleic acids using isotachophoresis
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
2012; 109 (28): 11127-11132
Abstract
We use isotachophoresis (ITP) to control and increase the rate of nucleic acid hybridization reactions in free solution. We present a new physical model, validation experiments, and demonstrations of this assay. We studied the coupled physicochemical processes of preconcentration, mixing, and chemical reaction kinetics under ITP. Our experimentally validated model enables a closed form solution for ITP-aided reaction kinetics, and reveals a new characteristic time scale which correctly predicts order 10,000-fold speed-up of chemical reaction rate for order 100 pM reactants, and greater enhancement at lower concentrations. At 500 pM concentration, we measured a reaction time which is 14,000-fold lower than that predicted for standard second-order hybridization. The model and method are generally applicable to acceleration of reactions involving nucleic acids, and may be applicable to a wide range of reactions involving ionic reactants.
View details for DOI 10.1073/pnas.1205004109
View details for Web of Science ID 000306642100027
View details for PubMedID 22733732
View details for PubMedCentralID PMC3396536
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Endoscopic imaging of Cerenkov luminescence
BIOMEDICAL OPTICS EXPRESS
2012; 3 (6): 1215-1225
Abstract
We demonstrate feasibility of endoscopic imaging of Cerenkov light originated when charged nuclear particles, emitted from radionuclides, travel through a biological tissue of living subjects at superluminal velocity. The endoscopy imaging system consists of conventional optical fiber bundle/ clinical endoscopes, an optical imaging lens system, and a sensitive low-noise charge coupled device (CCD) camera. Our systematic studies using phantom samples show that Cerenkov light from as low as 1 µCi of radioactivity emitted from (18)F-Fluorodeoxyglucose (FDG) can be coupled and transmitted through conventional optical fibers and endoscopes. In vivo imaging experiments with tumor bearing mice, intravenously administered with (18)F-FDG, further demonstrated that Cerenkov luminescence endoscopy is a promising new tool in the field of endoscopic molecular imaging.
View details for Web of Science ID 000304965700007
View details for PubMedID 22741069
View details for PubMedCentralID PMC3370963
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Molecular imaging of urothelial cancer using EGFR-binding peptides
AMER ASSOC CANCER RESEARCH. 2012
View details for DOI 10.1158/1538-7445.AM2012-4595
View details for Web of Science ID 000209701601273
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Seeing it through: translational validation of new medical imaging modalities
BIOMEDICAL OPTICS EXPRESS
2012; 3 (4): 764-776
Abstract
Medical imaging is an invaluable tool for diagnosis, surgical guidance, and assessment of treatment efficacy. The Network for Translational Research (NTR) for Optical Imaging consists of four research groups working to "bridge the gap" between lab discovery and clinical use of fluorescence- and photoacoustic-based imaging devices used with imaging biomarkers. While the groups are using different modalities, all the groups face similar challenges when attempting to validate these systems for FDA approval and, ultimately, clinical use. Validation steps taken, as well as future needs, are described here. The group hopes to provide translational validation guidance for itself, as well as other researchers.
View details for Web of Science ID 000302788200009
View details for PubMedID 22574264
View details for PubMedCentralID PMC3345805
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INTEROBSERVER AGREEMENT AND ACCURACY OF CONFOCAL LASER ENDOMICROSCOPY FOR IN VIVO DIAGNOSIS OF BLADDER CANCER
ELSEVIER SCIENCE INC. 2012: E716
View details for DOI 10.1016/j.juro.2012.02.1791
View details for Web of Science ID 000302912503070
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In Situ Electrokinetic Enhancement for Self-Assembled-Monolayer-Based Electrochemical Biosensing
ANALYTICAL CHEMISTRY
2012; 84 (6): 2702-2707
Abstract
This study reports a multifunctional electrode approach which directly implements electrokinetic enhancement on a self-assembled-monolayer-based electrochemical sensor for point-of-care diagnostics. Using urinary tract infections as a model system, we demonstrate that electrokinetic enhancement, which involves in situ stirring and heating, can enhance the sensitivity of the strain specific 16S rRNA hybridization assay for 1 order of magnitude and accelerate the time-limiting incubation step with a 6-fold reduction in the incubation time. Since the same electrode platform is used for both electrochemical signal enhancement and electrochemical sensing, the multifunctional electrode approach provides a highly effective strategy toward fully integrated lab-on-a-chip systems for various biomedical applications.
View details for DOI 10.1021/ac203245j
View details for Web of Science ID 000301634500013
View details for PubMedID 22397486
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Next generation of optical diagnostics for bladder cancer using probe-based confocal laser endomicroscopy
Conference on Photonic Therapeutics and Diagnostics VIII
SPIE-INT SOC OPTICAL ENGINEERING. 2012
View details for DOI 10.1117/12.907623
View details for Web of Science ID 000302580900030
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In vivo Cellular and Molecular Imaging: Future of Cancer Diagnosis and Surgery?
IEEE. 2012
View details for Web of Science ID 000322438500036
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A Universal Electrode Approach for Automated Electrochemical Detection of Bacterial 16S rRNA
IEEE. 2012
View details for Web of Science ID 000322438500077
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A Universal Electrode Approach for Automated Electrochemical Detection of Bacterial 16S rRNA
6th IEEE International Conference on Nano/Molecular Medicine and Engineering (IEEE-NANOMED)
IEEE. 2012: 96–100
View details for Web of Science ID 000322438500120
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Clinical Validation of Integrated Nucleic Acid and Protein Detection on an Electrochemical Biosensor Array for Urinary Tract Infection Diagnosis
PLOS ONE
2011; 6 (10)
Abstract
Urinary tract infection (UTI) is a common infection that poses a substantial healthcare burden, yet its definitive diagnosis can be challenging. There is a need for a rapid, sensitive and reliable analytical method that could allow early detection of UTI and reduce unnecessary antibiotics. Pathogen identification along with quantitative detection of lactoferrin, a measure of pyuria, may provide useful information towards the overall diagnosis of UTI. Here, we report an integrated biosensor platform capable of simultaneous pathogen identification and detection of urinary biomarker that could aid the effectiveness of the treatment and clinical management.The integrated pathogen 16S rRNA and host lactoferrin detection using the biosensor array was performed on 113 clinical urine samples collected from patients at risk for complicated UTI. For pathogen detection, the biosensor used sandwich hybridization of capture and detector oligonucleotides to the target analyte, bacterial 16S rRNA. For detection of the protein biomarker, the biosensor used an analogous electrochemical sandwich assay based on capture and detector antibodies. For this assay, a set of oligonucleotide probes optimized for hybridization at 37°C to facilitate integration with the immunoassay was developed. This probe set targeted common uropathogens including E. coli, P. mirabilis, P. aeruginosa and Enterococcus spp. as well as less common uropathogens including Serratia, Providencia, Morganella and Staphylococcus spp. The biosensor assay for pathogen detection had a specificity of 97% and a sensitivity of 89%. A significant correlation was found between LTF concentration measured by the biosensor and WBC and leukocyte esterase (p<0.001 for both).We successfully demonstrate simultaneous detection of nucleic acid and host immune marker on a single biosensor array in clinical samples. This platform can be used for multiplexed detection of nucleic acid and protein as the next generation of urinary tract infection diagnostics.
View details for DOI 10.1371/journal.pone.0026846
View details for Web of Science ID 000296916000027
View details for PubMedID 22066011
View details for PubMedCentralID PMC3204982
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Molecular Detection of Bacterial Pathogens Using Microparticle Enhanced Double-Stranded DNA Probes
ANALYTICAL CHEMISTRY
2011; 83 (16): 6349-6354
Abstract
Rapid, specific, and sensitive detection of bacterial pathogens is essential toward clinical management of infectious diseases. Traditional approaches for pathogen detection, however, often require time-intensive bacterial culture and amplification procedures. Herein, a microparticle enhanced double-stranded DNA probe is demonstrated for rapid species-specific detection of bacterial 16S rRNA. In this molecular assay, the binding of the target sequence to the fluorophore conjugated probe thermodynamically displaces the quencher probe and allows the fluorophore to fluoresce. By incorporation of streptavidin-coated microparticles to localize the biotinylated probes, the sensitivity of the assay can be improved by 3 orders of magnitude. The limit of detection of the assay is as few as eight bacteria without target amplification and is highly specific against other common pathogens. Its applicability toward clinical diagnostics is demonstrated by directly identifying bacterial pathogens in urine samples from patients with urinary tract infections.
View details for DOI 10.1021/ac2012575
View details for Web of Science ID 000293758800034
View details for PubMedID 21718053
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Dynamic Real-time Microscopy of the Urinary Tract Using Confocal Laser Endomicroscopy
UROLOGY
2011; 78 (1): 225-231
Abstract
To develop the diagnostic criteria for benign and neoplastic conditions of the urinary tract using probe-based confocal laser endomicroscopy (pCLE), a new technology for dynamic, in vivo imaging with micron-scale resolution. The suggested diagnostic criteria will formulate a guide for pCLE image interpretation in urology.Patients scheduled for transurethral resection of bladder tumor (TURBT) or nephrectomy were recruited. After white-light cystoscopy (WLC), fluorescein was administered as contrast. Different areas of the urinary tract were imaged with pCLE via direct contact between the confocal probe and the area of interest. Confocal images were subsequently compared with standard hematoxylin and eosin analysis.pCLE images were collected from 66 participants, including 2 patients who underwent nephrectomy. We identified key features associated with different anatomic landmarks of the urinary tract, including the kidney, ureter, bladder, prostate, and urethra. In vivo pCLE of the bladder demonstrated distinct differences between normal mucosa and neoplastic tissue. Using mosaicing, a post hoc image-processing algorithm, individual image frames were juxtaposed to form wide-angle views to better evaluate tissue microarchitecture.In contrast to standard pathologic analysis of fixed tissue with hematoxylin and eosin, pCLE provides real time microscopy of the urinary tract to enable dynamic interrogation of benign and neoplastic tissues in vivo. The diagnostic criteria developed in this study will facilitate adaptation of pCLE for use in conjunction with WLC to expedite diagnosis of urinary tract pathology, particularly bladder cancer.
View details for DOI 10.1016/j.urology.2011.02.057
View details for Web of Science ID 000292080300062
View details for PubMedID 21601243
View details for PubMedCentralID PMC4038103
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Biosensor diagnosis of urinary tract infections: a path to better treatment?
TRENDS IN PHARMACOLOGICAL SCIENCES
2011; 32 (6): 330-336
Abstract
Urinary tract infection (UTI) is among the most common bacterial infections and poses a significant healthcare burden. The standard culture-based diagnosis of UTI has a typical delay of two to three days. In the absence of definitive microbiological diagnosis at the point of care, physicians frequently initiate empirical broad-spectrum antibiotic treatment, and this has contributed to the emergence of resistant pathogens. Biosensors are emerging as a powerful diagnostic platform for infectious diseases. Paralleling how blood glucose sensors revolutionized the management of diabetes, and how pregnancy tests are now conducted in the home, biosensors are poised to improve UTI diagnosis significantly. Biosensors are amenable to integration with microfluidic technology for point-of-care (POC) applications. This review focuses on promising biosensor technology for UTI diagnosis, including pathogen identification and antimicrobial susceptibility testing, and hurdles to be surpassed in the translation of biosensor technology from bench to bedside.
View details for DOI 10.1016/j.tips.2011.03.001
View details for Web of Science ID 000291843800002
View details for PubMedID 21458868
View details for PubMedCentralID PMC3106133
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Comparison of 2.6-and 1.4-mm Imaging Probes for Confocal Laser Endomicroscopy of the Urinary Tract
JOURNAL OF ENDOUROLOGY
2011; 25 (6): 917-921
Abstract
Probe-based confocal laser endomicroscopy (pCLE) is an emerging technology for dynamic, in vivo imaging of the urinary tract with micron-scale resolution. We conducted a comparative analysis of pCLE with a 2.6-mm probe and a 1.4-mm probe that is compatible with flexible endoscopes.Sixty-seven patients scheduled for bladder tumor resection were recruited. pCLE imaging was performed using 2.6- and 1.4-mm probes. Image quality with the different probes was examined and further compared with standard histopathology.Images with the 2.6-mm probe have better resolution of cell morphology. The 1.4-mm probe has a wider field of view and better view of microarchitecture. While image quality with the 2.6-mm probe is superior, the 1.4-mm probe is compatible with flexible cystoscopy and maneuverability is maintained, enabling imaging of areas of the bladder that were previously challenging to access with the larger probe.The optical specifications of the 2.6-mm probe are more suitable for distinguishing urinary tract histopathology. Further design optimization to improve resolution and additional validation of the diagnostic accuracy of the smaller probe are needed to help extend application of pCLE for optical biopsy of the upper and lower urinary tract.
View details for DOI 10.1089/end.2010.0686
View details for Web of Science ID 000291553500004
View details for PubMedID 21568756
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Rapid Detection of Urinary Tract Infections Using Isotachophoresis and Molecular Beacons
ANALYTICAL CHEMISTRY
2011; 83 (11): 4110-4117
Abstract
We present a novel assay for rapid detection and identification of bacterial urinary tract infections using isotachophoresis (ITP) and molecular beacons. We applied on-chip ITP to extract and focus 16S rRNA directly from bacterial lysate and used molecular beacons to achieve detection of bacteria specific sequences. We demonstrated detection of E. coli in bacteria cultures as well as in patient urine samples in the clinically relevant range 1E6-1E8 cfu/mL. For bacterial cultures we further demonstrate quantification in this range. The assay requires minimal sample preparation (a single centrifugation and dilution), and can be completed, from beginning of lysing to detection, in under 15 min. We believe that the principles presented here can be used for design of other rapid diagnostics or detection methods for pathogenic diseases.
View details for DOI 10.1021/ac200253x
View details for Web of Science ID 000290978500022
View details for PubMedID 21545089
View details for PubMedCentralID PMC3116659
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Phage display selection of cancer-specific peptides on human bladder for molecular imaging of bladder cancer
AMER ASSOC CANCER RESEARCH. 2011
View details for DOI 10.1158/1538-7445.AM2011-2233
View details for Web of Science ID 000209701405184
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Optical imaging of bladder cancer with cancer-specific molecular contrast agents
AMER ASSOC CANCER RESEARCH. 2011
View details for DOI 10.1158/1538-7445.AM2011-4146
View details for Web of Science ID 000209701405021
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URINARY PROTEOMIC ANALYSIS TO IDENTIFY HOST RESPONSE PROTEINS IN CATHETER-ASSOCIATED URINARY TRACT INFECTION
ELSEVIER SCIENCE INC. 2011: E474
View details for DOI 10.1016/j.juro.2011.02.793
View details for Web of Science ID 000209830100011
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A Biosensor Platform for Rapid Antimicrobial Susceptibility Testing Directly From Clinical Samples
JOURNAL OF UROLOGY
2011; 185 (1): 148-153
Abstract
A significant barrier to efficient antibiotic management of infection is that the standard diagnostic methodologies do not provide results at the point of care. The delays between sample collection and bacterial culture and antibiotic susceptibility reporting have led to empirical use of antibiotics, contributing to the emergence of drug resistant pathogens. As a key step toward the development of a point of care device for determining the antibiotic susceptibility of urinary tract pathogens, we report on a biosensor based antimicrobial susceptibility test.For assay development bacteria were cultured with or without antibiotics, and growth was quantitated by determining viable counts and electrochemical biosensor measurement of bacterial 16S rRNA. To determine antibiotic susceptibility directly from patient samples, urine was cultured on antibiotic plates for 2.5 hours and growth was determined by electrochemical measurement of bacterial 16S rRNA. For assay validation 252 urine samples were collected from patients at the Spinal Cord Injury Service at Veterans Affairs Palo Alto Health Care System. The biosensor based antimicrobial susceptibility test was completed for samples containing gram-negative organisms. Pathogen identification and antibiotic susceptibility results were compared between our assay and standard microbiological analysis.A direct biosensor quantitation of bacterial 16S rRNA can be used to monitor bacterial growth for a biosensor based antimicrobial susceptibility test. Clinical validation of a biosensor based antimicrobial susceptibility test with patient urine samples demonstrated that this test was 94% accurate in 368 pathogen-antibiotic tests compared to standard microbiological analysis.This biosensor based antimicrobial susceptibility test, in concert with our previously described pathogen identification assay, can provide culture and susceptibility information directly from a urine sample within 3.5 hours.
View details for DOI 10.1016/j.juro.2010.09.022
View details for Web of Science ID 000285141900047
View details for PubMedID 21074208
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System Integration - A Major Step toward Lab on a Chip
JOURNAL OF BIOLOGICAL ENGINEERING
2011; 5 (1)
Abstract
Microfluidics holds great promise to revolutionize various areas of biological engineering, such as single cell analysis, environmental monitoring, regenerative medicine, and point-of-care diagnostics. Despite the fact that intensive efforts have been devoted into the field in the past decades, microfluidics has not yet been adopted widely. It is increasingly realized that an effective system integration strategy that is low cost and broadly applicable to various biological engineering situations is required to fully realize the potential of microfluidics. In this article, we review several promising system integration approaches for microfluidics and discuss their advantages, limitations, and applications. Future advancements of these microfluidic strategies will lead toward translational lab-on-a-chip systems for a wide spectrum of biological engineering applications.
View details for DOI 10.1186/1754-1611-5-6
View details for Web of Science ID 000208904900006
View details for PubMedCentralID PMC3117764
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Real Time Diagnosis of Bladder Cancer with Probe-Based Confocal Laser Endomicroscopy
Conference on Imaging, Manipulation, and Analysis of Biomolecules, Cells, and Tissues IX
SPIE-INT SOC OPTICAL ENGINEERING. 2011
View details for DOI 10.1117/12.874243
View details for Web of Science ID 000297677500045
- Advances in the field of urinary tract infections European Urology Today Congress News 2011; 23: 27
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System Integration - A Major Step toward Lab on a Chip.
Journal of biological engineering
2011; 5: 6-?
Abstract
Microfluidics holds great promise to revolutionize various areas of biological engineering, such as single cell analysis, environmental monitoring, regenerative medicine, and point-of-care diagnostics. Despite the fact that intensive efforts have been devoted into the field in the past decades, microfluidics has not yet been adopted widely. It is increasingly realized that an effective system integration strategy that is low cost and broadly applicable to various biological engineering situations is required to fully realize the potential of microfluidics. In this article, we review several promising system integration approaches for microfluidics and discuss their advantages, limitations, and applications. Future advancements of these microfluidic strategies will lead toward translational lab-on-a-chip systems for a wide spectrum of biological engineering applications.
View details for DOI 10.1186/1754-1611-5-6
View details for PubMedID 21612614
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Hybrid electrokinetic manipulation in high-conductivity media
LAB ON A CHIP
2011; 11 (10): 1770-1775
Abstract
This study reports a hybrid electrokinetic technique for label-free manipulation of pathogenic bacteria in biological samples toward medical diagnostic applications. While most electrokinetic techniques only function in low-conductivity buffers, hybrid electrokinetics enables effective operation in high-conductivity samples, such as physiological fluids (∼1 S m(-1)). The hybrid electrokinetic technique combines short-range electrophoresis and dielectrophoresis, and long-range AC electrothermal flow to improve its effectiveness. The major technical hurdle of electrode instability for manipulating high conductivity samples is tackled by using a Ti-Au-Ti sandwich electrode and a 3-parallel-electrode configuration is designed for continuous isolation of bacteria. The device operates directly with biological samples including urine and buffy coats. We show that pathogenic bacteria and biowarfare agents can be concentrated for over 3 orders of magnitude using hybrid electrokinetics.
View details for DOI 10.1039/c1lc20054b
View details for Web of Science ID 000289951200009
View details for PubMedID 21487576
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Statistical Metamodeling for Revealing Synergistic Antimicrobial Interactions
PLOS ONE
2010; 5 (11)
Abstract
Many bacterial pathogens are becoming drug resistant faster than we can develop new antimicrobials. To address this threat in public health, a metamodel antimicrobial cocktail optimization (MACO) scheme is demonstrated for rapid screening of potent antibiotic cocktails using uropathogenic clinical isolates as model systems. With the MACO scheme, only 18 parallel trials were required to determine a potent antimicrobial cocktail out of hundreds of possible combinations. In particular, trimethoprim and gentamicin were identified to work synergistically for inhibiting the bacterial growth. Sensitivity analysis indicated gentamicin functions as a synergist for trimethoprim, and reduces its minimum inhibitory concentration for 40-fold. Validation study also confirmed that the trimethoprim-gentamicin synergistic cocktail effectively inhibited the growths of multiple strains of uropathogenic clinical isolates. With its effectiveness and simplicity, the MACO scheme possesses the potential to serve as a generic platform for identifying synergistic antimicrobial cocktails toward management of bacterial infection in the future.
View details for DOI 10.1371/journal.pone.0015472
View details for Web of Science ID 000284087800026
View details for PubMedID 21124958
View details for PubMedCentralID PMC2988685
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Electrochemical immunosensor detection of urinary lactoferrin in clinical samples for urinary tract infection diagnosis
BIOSENSORS & BIOELECTRONICS
2010; 26 (2): 649-654
Abstract
Urine is the most abundant and easily accessible of all body fluids and provides an ideal route for non-invasive diagnosis of human diseases, particularly of the urinary tract. Electrochemical biosensors are well suited for urinary diagnostics due to their excellent sensitivity, low-cost, and ability to detect a wide variety of target molecules including nucleic acids and protein biomarkers. We report the development of an electrochemical immunosensor for direct detection of the urinary tract infection (UTI) biomarker lactoferrin from infected clinical samples. An electrochemical biosensor array with alkanethiolate self-assembled monolayer (SAM) was used. Electrochemical impedance spectroscopy was used to characterize the mixed SAM, consisted of 11-mercaptoundecanoic acid and 6-mercapto-1-hexanol. A sandwich amperometric immunoassay was developed for detection of lactoferrin from urine, with a detection limit of 145 pg/ml. We validated lactoferrin as a biomarker of pyuria (presence of white blood cells in urine), an important hallmark of UTI, in 111 patient-derived urine samples. Finally, we demonstrated multiplex detection of urinary pathogens and lactoferrin through simultaneous detection of bacterial nucleic acid (16S rRNA) and host immune response protein (lactoferrin) on a single sensor array. Our results represent first integrated sensor platform capable of quantitative pathogen identification and measurement of host immune response, potentially providing clinical diagnosis that is not only more expeditious but also more informative than the current standard.
View details for DOI 10.1016/j.bios.2010.07.002
View details for Web of Science ID 000283804400056
View details for PubMedID 20667707
View details for PubMedCentralID PMC2946447
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DYNAMIC REAL TIME MICROSCOPY OF THE URINARY TRACT: AN IMAGING ATLAS BASED ON CONFOCAL LASER ENDOMICROSCOPY
MARY ANN LIEBERT INC. 2010: A278–A278
View details for Web of Science ID 000283864901225
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Matrix Effects-A Challenge Toward Automation of Molecular Analysis
JALA
2010; 15 (3): 233-242
View details for DOI 10.1016/j.jala.2010.02.001
View details for Web of Science ID 000285163600013
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Nanomedicine: About This Special Issue
JALA
2010; 15 (2): A10
View details for DOI 10.1016/j.jala.2010.01.003
View details for Web of Science ID 000285163500003
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Antimicrobial Susceptibility Testing Using High Surface-to-Volume Ratio Microchannels
ANALYTICAL CHEMISTRY
2010; 82 (3): 1012-1019
Abstract
This study reports the use of microfluidics, which intrinsically has a large surface-to-volume ratio, toward rapid antimicrobial susceptibility testing at the point of care. By observing the growth of uropathogenic Escherichia coli in gas permeable polymeric microchannels with different dimensions, we demonstrate that the large surface-to-volume ratio of microfluidic systems facilitates rapid growth of bacteria. For microchannels with 250 microm or less in depth, the effective oxygenation can sustain the growth of E. coli to over 10(9) cfu/mL without external agitation or oxygenation, which eliminates the requirement of bulky instrumentation and facilitates rapid bacterial growth for antimicrobial susceptibility testing at the point of care. The applicability of microfluidic rapid antimicrobial susceptibility testing is demonstrated in culture media and in urine with clinical bacterial isolates that have different antimicrobial resistance profiles. The antimicrobial resistance pattern can be determined as rapidly as 2 h compared to days in standard clinical procedures facilitating diagnostics at the point of care.
View details for DOI 10.1021/ac9022764
View details for Web of Science ID 000273983700037
View details for PubMedID 20055494
View details for PubMedCentralID PMC2821038
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Laparoscopic Radical Nephrectomy in a Pelvic Ectopic Kidney: Keys to Success
JSLS-JOURNAL OF THE SOCIETY OF LAPAROENDOSCOPIC SURGEONS
2010; 14 (1): 126-129
Abstract
Laparoscopic radical nephrectomy of a pelvic kidney for renal cell carcinoma is a procedure with little precedent, but one that offers the advantages of the minimally invasive approach. We present our experience with this unique procedure.A 64-year-old male with a history of end-stage renal disease was diagnosed with a 2.6-cm enhancing mass in a pelvic left kidney with 2 separate sources of blood supply. He was offered either an open radical nephrectomy or a laparoscopic radical nephrectomy and opted for the minimally invasive approach.The procedure was performed successfully without complications and with minimal blood loss. The case was marked both by difficulty in mobilizing the sigmoid colon and the limited working space of the pelvis, which made localization of the numerous hilar vessels challenging.Laparoscopic radical nephrectomy for a pelvic ectopic kidney appears to be safe and efficacious. Success is dependent on familiarity with pelvic anatomy, optimal port placement, and preprocedure knowledge of the often-complicated vascular anatomy of the ectopic kidney. Preoperative imaging to delineate anomalous vascular anatomy is mandatory, and ureteral catheter placement is helpful for intraoperative identification purposes.
View details for DOI 10.4293/108680810X12674612765623
View details for Web of Science ID 000278761200023
View details for PubMedID 20529537
View details for PubMedCentralID PMC3021314
- Electrothermal Fluid Manipulation of High-Conductivity Samples for Laboratory Automation Applications Journal of the Association for Laboratory Automation 2010; 15 (6): 426-432
- Nanomedicine: About This Special Issue Journal of the Association for Laboratory Automation 2010; 15 (2): A10
- Matrix Effects?A Challenge Toward Automation of Molecular Analysis Journal of the Association for Laboratory Automation 2010; 15 (3): 233-242
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Multiplex Pathogen Identification for Polymicrobial Urinary Tract Infections Using Biosensor Technology: A Prospective Clinical Study
JOURNAL OF UROLOGY
2009; 182 (6): 2735-2741
Abstract
Rapid diagnosis of urinary tract infection would have a significant beneficial impact on clinical management, particularly in patients with structural or functional urinary tract abnormalities who are highly susceptible to recurrent polymicrobial infections. We examined the analytical validity of an electrochemical biosensor array for rapid molecular diagnosis of urinary tract infection in a prospective clinical study in patients with neurogenic bladder.The electrochemical biosensor array was functionalized with DNA probes against 16S rRNA of the most common uropathogens. Spinal cord injured patients at a Veterans Affairs hospital were recruited into the study. Urine samples were generally tested on the biosensor within 1 to 2 hours of collection. Biosensor results were compared with those obtained using standard clinical microbiology laboratory methods.We successfully developed a 1-hour biosensor assay for multiplex identification of pathogens. From July 2007 to December 2008 we recruited 116 patients, yielding a total of 109 urine samples suitable for analysis and comparison between biosensor assay and standard urine culture. Of the samples 74% were positive, of which 42% were polymicrobial. We identified 20 organisms, of which Escherichia coli, Pseudomonas aeruginosa and Enterococcus species were the most common. Biosensor assay specificity and positive predictive value were 100%. Pathogen detection sensitivity was 89%, yielding a 76% negative predictive value.To our knowledge we report the first prospective clinical study to successfully identify pathogens within a point of care time frame using an electrochemical biosensor platform. Additional efforts to improve the limit of detection and probe design are needed to further enhance assay sensitivity.
View details for DOI 10.1016/j.juro.2009.08.028
View details for Web of Science ID 000271668600072
View details for PubMedID 19837423
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A Microfluidic Cartridge System for Multiplexed Clinical Analysis
JALA
2009; 14 (6): 407-412
Abstract
Cartridge-based microfluidics is a promising technology for clinical diagnostics. By miniaturizing the fluid-handling processes required for genomic and proteomic analyses, reagent and specimen volume is minimized along with the size of the system. We demonstrate an automated microfluidic system capable of performing six multiplexed genomic and proteomic analyses simultaneously, by means of an integrated electrochemical sensor and embedded controls.
View details for DOI 10.1016/j.jala.2009.05.002
View details for Web of Science ID 000285163400011
View details for PubMedCentralID PMC2808045
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Matrix-insensitive protein assays push the limits of biosensors in medicine
NATURE MEDICINE
2009; 15 (11): 1327-U130
Abstract
Advances in biosensor technologies for in vitro diagnostics have the potential to transform the practice of medicine. Despite considerable work in the biosensor field, there is still no general sensing platform that can be ubiquitously applied to detect the constellation of biomolecules in diverse clinical samples (for example, serum, urine, cell lysates or saliva) with high sensitivity and large linear dynamic range. A major limitation confounding other technologies is signal distortion that occurs in various matrices due to heterogeneity in ionic strength, pH, temperature and autofluorescence. Here we present a magnetic nanosensor technology that is matrix insensitive yet still capable of rapid, multiplex protein detection with resolution down to attomolar concentrations and extensive linear dynamic range. The matrix insensitivity of our platform to various media demonstrates that our magnetic nanosensor technology can be directly applied to a variety of settings such as molecular biology, clinical diagnostics and biodefense.
View details for DOI 10.1038/nm.2032
View details for Web of Science ID 000271543700023
View details for PubMedID 19820717
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Optical Biopsy of Human Bladder Neoplasia With In Vivo Confocal Laser Endomicroscopy
JOURNAL OF UROLOGY
2009; 182 (4): 1299-1305
Abstract
Confocal laser endomicroscopy is a new endoscopic imaging technology that could complement white light cystoscopy by providing in vivo bladder histopathology. We evaluated confocal laser endomicroscopy by imaging normal, malignant appearing and indeterminate bladder mucosa in a pilot study.Patients scheduled to undergo transurethral resection of bladder tumors were recruited during a 3-month period. After standard cystoscopy fluorescein was administered intravesically and/or intravenously as a contrast dye. A 2.6 mm probe based confocal laser endomicroscope was passed through a 26 Fr resectoscope to image normal and abnormal appearing areas. The images were collected with 488 nm excitation at 8 to 12 frames per second. The endomicroscopic images were compared with standard hematoxylin and eosin analysis of transurethral resection of bladder tumor specimens.Of the 27 recruited patients 8 had no cancer, 9 had low grade tumors, 9 had high grade tumors and 1 had a low grade tumor with a high grade focus. Endomicroscopic images demonstrated clear differences between normal mucosa, and low and high grade tumors. In normal urothelium larger umbrella cells are seen most superficially followed by smaller intermediate cells and the less cellular lamina propria. In contrast, low grade papillary tumors demonstrate densely arranged but normal-shaped small cells extending outward from fibrovascular cores. High grade tumors show markedly irregular architecture and cellular pleomorphism.We report the first study to our knowledge of in vivo confocal laser endomicroscopy in the urinary tract. Marked differences among normal urothelium, low grade tumors and high grade tumors were visualized. Pending further clinical investigation and technological improvement, confocal laser endomicroscopy may become a useful adjunct to conventional cystoscopy.
View details for DOI 10.1016/j.juro.2009.06.039
View details for Web of Science ID 000269764100016
View details for PubMedID 19683270
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Decreasing Use of Luteinizing Hormone-Releasing Hormone Agonists in the United States is Independent of Reimbursement Changes: A Medicare and Veterans Health Administration Claims Analysis
JOURNAL OF UROLOGY
2009; 182 (1): 255-260
Abstract
Luteinizing hormone-releasing hormone agonists are the most common form of androgen deprivation therapy in men with prostate cancer. Limited data exist regarding physician decision-making in prescribing luteinizing hormone-releasing hormone agonists. We present an analysis of luteinizing hormone-releasing hormone agonist use trends based on a time matched comparison of data from Medicare and the Veterans Health Administration, a health care system unaffected by recent changes in Medicare reimbursement implemented by the Medicare Modernization Act in 2004.Medicare claims and payment data were obtained from the Centers for Medicare and Medicaid Services from 2003 to 2007 for luteinizing hormone-releasing hormone agonists and for simple orchiectomy. The Veterans Health Administration Pharmacy Benefits Management database was queried for the annual number of prescriptions for luteinizing hormone-releasing hormone agonists during the same period.After implementation of the Medicare Prescription Drug, Improvement and Modernization Act in 2004 the reimbursement of luteinizing hormone-releasing hormone agonists in the Medicare population decreased by 54.8% and annual claims decreased by 25.1% from 2004 to 2007. During the same period luteinizing hormone-releasing hormone agonist use decreased by 16.8% in the Veterans Health Administration population. There was no compensatory increase in the use of simple orchiectomy for androgen deprivation therapy during the study period.Use of luteinizing hormone-releasing hormone agonists has decreased in the Medicare and Veterans Health Administration populations since 2004 without a compensatory increase in the use of alternative forms of androgen deprivation therapy. The shift in practice patterns is likely due to a decrease in Medicare reimbursement for these drugs, an increase in the use of intermittent therapy and increased recognition of the adverse effects associated with androgen deprivation therapy.
View details for DOI 10.1016/j.juro.2009.02.141
View details for Web of Science ID 000266949800108
View details for PubMedID 19450844
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Active Manipulation of Quantum Dots using AC Electrokinetics
JOURNAL OF PHYSICAL CHEMISTRY C
2009; 113 (16): 6561-6565
View details for DOI 10.1021/jp9004423
View details for Web of Science ID 000265383300032
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DECREASING UTILIZATION OF LHRH-AGONISTS IN THE UNITED STATES IS INDEPENDENT OF REIMBURSEMENT CHANGES: A MEDICARE AND VETERANS HEALTH ADMINISTRATION CLAIMS ANALYSIS
ELSEVIER SCIENCE INC. 2009: 77
View details for DOI 10.1016/S0022-5347(09)60222-6
View details for Web of Science ID 000264448500209
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Fibered Confocal Microscopy of Bladder Tumors: An ex Vivo Study
JOURNAL OF ENDOUROLOGY
2009; 23 (2): 197-201
Abstract
The inadequacy of white-light cystoscopy to detect flat bladder tumors is well recognized. Great interest exists in developing other imaging technologies to augment or supplant conventional cystoscopy. Fibered confocal microscopy offers the promise of providing in vivo histopathologic information to help distinguish malignant from benign bladder lesions. We report the initial use of this technology to visualize tumors in the human bladder.We performed ex vivo fibered confocal imaging of fresh radical cystectomy specimens using the Mauna Kea Technologies Cellvizio system. The findings were compared with results from standard histopathology.The bladders of four patients were imaged using the fibered confocal microscope. Normal and neoplastic urothelium manifested differences in cellular and vascular density.This study demonstrates the feasibility of using fibered confocal microscopy to detect histologic differences between normal and neoplastic urothelium, and establishes a foundation for the use of fiber-based confocal microscopy in clinical studies.
View details for DOI 10.1089/end.2008.0524
View details for Web of Science ID 000263355500005
View details for PubMedID 19196063
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Rapid multiplex identification of pathogens in polymicrobial urinary tract infections
ELSEVIER SCIENCE INC. 2008: 82–83
View details for DOI 10.1016/S0022-5347(08)60240-2
View details for Web of Science ID 000254175300233
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A case of prostatic adenocarcinoma recurrence presenting as ductal carcinoma of the prostate
NATURE CLINICAL PRACTICE UROLOGY
2008; 5 (1): 55-58
Abstract
A 61-year-old man with a history of recurrent prostate cancer presented with obstructive urinary symptoms. He had been diagnosed with locally invasive adenocarcinoma of the prostate 10 years previously and treated with neoadjuvant hormonal and external beam radiation therapies. Because of the patient's rising PSA level, he had been started on goserelin 6 years after this diagnosis and bicalutamide 6 months before the current presentation. The patient presented to the urology clinic with worsening lower urinary tract symptoms consisting of nocturia, urgency, and weak stream.Physical examination revealed a largely normal digital rectal examination, although there was slight asymmetry. The post-void residual urine volume was approximately 200 ml. Laboratory tests showed no evidence of urinary tract infection, but confirmed a rising PSA level despite low serum testosterone levels. Cystoscopic examination revealed hypervascular, large lateral prostatic lobes obstructing the bladder neck. The bladder was normal.The patient underwent transurethral resection of the prostate. Soon after the resection started, bilateral papillary tumors arising from the stroma of both prostatic lobes were uncovered. Owing to the diffuse nature of the papillary tumors, complete resection was not possible. Pathologic analysis confirmed the presence of ductal carcinoma of the prostate.The patient had an uneventful postoperative course and reported improvement of voiding symptoms. Staging with bone scan and CT of the abdomen and pelvis demonstrated multi-focal bony metastasis. The patient was started on docetaxel-based chemotherapy for hormone refractory recurrence of prostate cancer as ductal carcinoma of the prostate. He remains under close surveillance for clinical response and progression of disease.
View details for DOI 10.1038/ncpuro0994
View details for Web of Science ID 000252111100013
View details for PubMedID 18185514
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Use of haemostatic agents and glues during laparoscopic partial nephrectomy: A multi-institutional survey from the United States and Europe of 1347 cases
EUROPEAN UROLOGY
2007; 52 (3): 798-803
Abstract
Laparoscopic partial nephrectomy (LPN) is a technically challenging procedure for the management of renal tumours. Major complications of LPN include bleeding and urine leakage. Haemostatic agents (HAs) and/or glues may reduce haemorrhage and urine leakage. We sought to examine the current practice patterns for urologists performing LPN with regard to HA use and its relationship with bleeding and urine leakage.A survey was sent via e-mail to urologists currently performing LPN in centres in the United States and Europe. We queried the indications for HA/glue usage, type of HAs/glues used, and whether concomitant suturing/bolstering was performed. In addition, the total number of LPNs performed, laparoscopic tools used to resect the tumour, tumour size, and tumour position were queried.Surveys suitable for analysis were received from 18 centres (n=1347 cases). HAs and/or glues were used in 1042 (77.4%) cases. Mean tumour size was 2.8cm, with 79% of the tumours being defined as exophytic and 21% deep. The HAs and glues used included gelatin matrix thrombin (FloSeal), fibrin gel (Tisseel), bovine serum albumin (BioGlue), cyanoacrylate glue (Glubran), oxidized regenerated cellulose (Surgicel), or combinations of these. Sixteen centres performed concomitant suturing/bolstering. The overall postoperative bleeding requiring transfusion and urine leakage rates were 2.7% and 1.9%, respectively.The use of HAs and/or glues is routine in most centres performing LPN. The overall haemorrhage and urine leakage rates are low following LPN. More studies are needed to assess the potential role of HAs and/or glues in LPN.
View details for Web of Science ID 000249198400028
View details for PubMedID 17329015
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Positive margins in laparoscopic partial nephrectomy in 855 cases: A multi-institutional survey from the United States and Europe
JOURNAL OF UROLOGY
2007; 178 (1): 47-50
Abstract
Open partial nephrectomy has emerged as the standard of care in the management of renal tumors smaller than 4 cm. While laparoscopic radical nephrectomy has been shown to be comparable to open radical nephrectomy with respect to long-term outcomes, important questions remain unanswered regarding the oncological efficacy of laparoscopic partial nephrectomy. We examined the practice patterns and pathological outcomes following laparoscopic partial nephrectomy.A survey was sent to academic medical centers in the United States and in Europe performing laparoscopic partial nephrectomy. The total number of laparoscopic partial nephrectomies, positive margins, indications for intraoperative frozen biopsy as well as tumor size and position were queried.Surveys suitable for analysis were received from 17 centers with a total of 855 laparoscopic partial nephrectomy cases. Mean tumor size was 2.7 cm (+/-0.6). There were 21 cases with positive margins on final pathology, giving an overall positive margin rate of 2.4%. Intraoperative frozen sections were performed selectively at 10 centers based on clinical suspicion of positive margins on excised tumor. Random biopsies were routinely performed on the resection bed at 5 centers. Frozen sections were never performed at 2 centers. Of the 21 cases with positive margins 14 underwent immediate radical nephrectomy based on the frozen section and 7 were followed expectantly.Early experience with laparoscopic partial nephrectomy in this multicenter study demonstrates oncological efficacy comparable to that of open partial nephrectomy with respect to the incidence of positive margins. The practice of intraoperative frozen sections varied among centers and is not definitive in guiding the optimal surgical treatment.
View details for DOI 10.1016/j.juro.2007.03.045
View details for Web of Science ID 000247197000012
View details for PubMedID 17574057
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Association of bowel rest and ketorolac analgesia with short hospital stay after laparoscopic donor nephrectomy
UROLOGY
2007; 69 (5): 828-831
Abstract
Because of the shortage of cadaveric kidneys for allograft transplantation, laparoscopic donor nephrectomy is becoming a more feasible option. Several large published series have reported hospital stays as long as 3.3 days. We report the positive effect of preoperative bowel rest and the use of ketorolac for postoperative analgesia on reducing the hospital stay after laparoscopic donor nephrectomy.From 2000 to 2005, 300 patients underwent laparoscopic donor nephrectomy at our institution by a single surgeon (P.G.S.). All patients underwent a bowel preparation regimen involving a clear liquid diet beginning 2 days before surgery. Furthermore, two bottles of magnesium citrate were taken orally the day before surgery, and all patients fasted after midnight before surgery. Patients self-administered one Fleets enema the evening before surgery. Postoperatively, the patients received ketorolac 30 mg intravenously every 6 hours for a maximum of 48 hours, with additional narcotics if necessary for analgesia.The mean operative time was 180 +/- 55 minutes. Typically, patients were admitted the day of surgery and discharged the next postoperative day. The mean donor hospital stay was 1.1 days (range 1 to 3) with no readmissions. More than 97% of our patients were able to tolerate a clear liquid diet, pass flatus, and ambulate the day after surgery.With implementation of a strict bowel preparation regimen and the use of ketorolac for postoperative analgesia, the donor length of stay was markedly improved from previously published results. We attribute the shorter hospital stay to the quicker return of bowel function and to less postoperative discomfort.
View details for DOI 10.1016/j.urology.2007.01.083
View details for Web of Science ID 000248119400008
View details for PubMedID 17482915
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Development of an advanced electrochemical DNA biosensor for bacterial pathogen detection
JOURNAL OF MOLECULAR DIAGNOSTICS
2007; 9 (2): 158-168
Abstract
Electrochemical sensors have the capacity for rapid and accurate detection of a wide variety of target molecules in biological fluids. We have developed an electrochemical sensor assay involving hybridization of bacterial 16S rRNA to fluorescein-modified detector probes and to biotin-modified capture probes anchored to the sensor surface. Signal is generated by an oxidation-reduction current produced by the action of horseradish peroxidase conjugated to an anti-fluorescein monoclonal Fab. A previous study found that this electrochemical sensor strategy could identify uropathogens in clinical urine specimens. To improve assay sensitivity, we examined the key steps that affect the current amplitude of the electrochemical signal. Efficient lysis and release of 16S rRNA from both gram-negative and -positive bacteria was achieved with an initial treatment with Triton X-100 and lysozyme followed by alkaline lysis, resulting in a 12-fold increase in electrochemical signal compared with alkaline lysis alone. The distance in nucleotides between the target hybridization sites of the detector and capture probes and the location of fluorescein modification on the detector probe contributed to a 23-fold change in signal intensity. These results demonstrate the importance of target-probe and probe-probe interactions in the detection of bacterial 16S rRNA using an electrochemical DNA sensor approach.
View details for DOI 10.2353/jmoldx.2007.060052
View details for Web of Science ID 000245427600005
View details for PubMedID 17384207
View details for PubMedCentralID PMC1867445
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Laparoscopic renal surgery for benign disease.
Current urology reports
2007; 8 (1): 12-18
Abstract
Fifteen years after the first report, laparoscopic nephrectomy has demonstrated proven efficacy and safety comparable with an open approach, with a significant advantage of a faster recovery. Wide dissemination of these surgical techniques and continued improvement in instrumentation has made laparoscopy the preferred approach for treating benign pathologic conditions of the kidney. In this review, the expanding indications of laparoscopic simple nephrectomy and the outcomes of the larger clinical series are examined. We discuss the technical aspects of both transperitoneal and retroperitoneal approaches. Finally, laparoscopic cyst decortication and some of the novel applications of laparoscopic renal surgery are highlighted.
View details for PubMedID 17239312
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A Microfluidic System for Rapid Bacterial Pathogen Detection
7th IEEE Conference on Nanotechnology
IEEE. 2007: 1341–1345
View details for Web of Science ID 000261434900301
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Complications of laparoscopic living donor nephrectomy and their management: The UCLA experience
UROLOGY
2007; 69 (1): 49-52
Abstract
Because of the shortage of cadaveric kidneys, laparoscopic living donor nephrectomy (LLDN) has become a more common option for transplant recipients. The complication rate has been reported at 6.4% to 16.5%. We present the initial University of California, Los Angeles experience with the complications and their management during LLDN.From January 2000 to December 2005, a single surgeon performed 300 consecutive LLDNs at our institution. A committee of urologists, nephrologists, and support staff approved each donor before surgery. After LLDN was completed, the patients received 30 mg of ketorolac intravenously every 6 hours until discharge. We reviewed the intraoperative and postoperative complications and their management at our institution.Three patients required open conversion, for an overall conversion rate of 1%. Two of the three conversions were a result of a major vascular complication (0.6%). The first major vascular complication resulted from an endovascular stapler malfunction during transection of an accessory left renal artery. The second vascular complication was a Veress needle injury to the left common iliac artery. Three postoperative major complications (1%) occurred, including 1 case of rhabdomyolysis and 2 cases of chylous ascites. Also, 7 minor postoperative complications (2.3%) occurred. Our overall complication rate was 4%. No patients died, and the mean hospital stay was 1.1 days.Our results have shown that LLDN is a safe procedure associated with low morbidity and a quick recovery. Appropriate patient selection is essential to ensure the safety of this procedure.
View details for DOI 10.1016/j.urology.2006.09.030
View details for Web of Science ID 000244114600016
View details for PubMedID 17270612
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Incidence of ureteral strictures after laparoscopic donor nephrectomy
JOURNAL OF UROLOGY
2006; 176 (3): 1065-1068
Abstract
Previous reports of laparoscopic donor nephrectomy have suggested that preservation of the gonadal vein with the specimen is important for preventing ureteral strictures. To test this hypothesis we examined our series of patients for the incidence of ureteral strictures when the gonadal vein was not preserved with the specimen during laparoscopic donor nephrectomy.We reviewed the records of 300 consecutive patients at our institution who underwent laparoscopic donor nephrectomy between 2000 and 2005. Mean donor age was 36.7 years (range 18 to 68) in the 167 female and 133 male donors. Mean recipient age was 38.4 years. Average followup was 2 years. During ureteral dissection the gonadal vein was transected just distal to the renal vein and left in situ. The ureter was dissected and transected at the level of the common iliac vessels. Indwelling ureteral stents were used for all recipient ureteral reimplantations and left in place for 1 month. In the postoperative period transplant recipients were followed biweekly for serum creatinine function during month 1 and monthly thereafter. All patients with increased creatinine (greater than 1.3 mg/dl) or an increasing trend were evaluated with transplant renal ultrasound. Clinically significant ureteral stricture was defined as persistent hydronephrosis resulting in impaired renal function and the need for percutaneous nephrostomy tube placement or ureteroscopic management.After laparoscopic living donor transplantation without gonadal vein preservation we found no incidence of clinically significant ureteral stricture.Gonadal vein preservation with the specimen during laparoscopic donor nephrectomy is not necessary. Preservation of the periureteral blood supply is sufficient to prevent ureteral strictures.
View details for DOI 10.1016/j.juro.2006.04.079
View details for Web of Science ID 000239740800054
View details for PubMedID 16890691
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Use of electrochemical DNA biosensors for rapid molecular identification of uropathogens in clinical urine specimens
JOURNAL OF CLINICAL MICROBIOLOGY
2006; 44 (2): 561-570
Abstract
We describe the first species-specific detection of bacterial pathogens in human clinical fluid samples using a microfabricated electrochemical sensor array. Each of the 16 sensors in the array consisted of three single-layer gold electrodes-working, reference, and auxiliary. Each of the working electrodes contained one representative from a library of capture probes, each specific for a clinically relevant bacterial urinary pathogen. The library included probes for Escherichia coli, Proteus mirabilis, Pseudomonas aeruginosa, Enterocococcus spp., and the Klebsiella-Enterobacter group. A bacterial 16S rRNA target derived from single-step bacterial lysis was hybridized both to the biotin-modified capture probe on the sensor surface and to a second, fluorescein-modified detector probe. Detection of the target-probe hybrids was achieved through binding of a horseradish peroxidase (HRP)-conjugated anti-fluorescein antibody to the detector probe. Amperometric measurement of the catalyzed HRP reaction was obtained at a fixed potential of -200 mV between the working and reference electrodes. Species-specific detection of as few as 2,600 uropathogenic bacteria in culture, inoculated urine, and clinical urine samples was achieved within 45 min from the beginning of sample processing. In a feasibility study of this amperometric detection system using blinded clinical urine specimens, the sensor array had 100% sensitivity for direct detection of gram-negative bacteria without nucleic acid purification or amplification. Identification was demonstrated for 98% of gram-negative bacteria for which species-specific probes were available. When combined with a microfluidics-based sample preparation module, the integrated system could serve as a point-of-care device for rapid diagnosis of urinary tract infections.
View details for DOI 10.1128/JCM.44.2.561-570.2006
View details for Web of Science ID 000235344200042
View details for PubMedID 16455913
View details for PubMedCentralID PMC1392664
- Design of Microfluidic T-Form Mixer Utilizing Pressure Disturbances IEEE Nanotechnology Council Review on Advances of Micro, Nano, and Molecular Systems 2006; 1: 595
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A point-of-care micro-laboratory for direct pathogen identification in body fluids
IEEE International Conference of Nano/Micro Engineered and Molecular Systems
IEEE. 2006: 1109–1112
View details for Web of Science ID 000248485802019
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Rapid, species-specific detection of uropathogen 16S rDNA and rRNA at ambient temperature by dot-blot hybridization and an electrochemical sensor array
MOLECULAR GENETICS AND METABOLISM
2005; 84 (1): 90-99
Abstract
Development of rapid molecular approaches for pathogen detection is key to improving treatment of infectious diseases. For this study, the kinetics and temperature-dependence of DNA probe hybridization to uropathogen species-specific sequences were examined. A set of oligonucleotide probes were designed based on variable regions of the 16S gene of the Escherichia coli, Proteus mirabilis, Klebsiella oxytoca, and Pseudomonas aeruginosa. A universal bacterial probe and probes-specific for gram-positive and gram-negative organisms were also included. The oligonucleotide probes discriminated among 16S genes derived from 11 different species of uropathogenic bacteria applied to nylon membranes in a dot-blot format. Significant binding of oligonucleotide probes to target DNA and removal of nonspecific binding by membrane washing could both be achieved rapidly, requiring as little as 10 min. An oligonucleotide probe from the same species-specific region of the E. coli 16S gene was used as a capture probe in a novel electrochemical 16-sensor array based on microfabrication technology. Sequence-specific hybridization of target uropathogen 16S rDNA was detected through horseradish peroxidase acting as an electrochemical transducer via a second, detector probe. The sensor array demonstrated rapid, species-specific hybridization in a time course consistent with the rapid kinetics of the dot-blot hybridization studies. As in the dot-blot hybridization studies, species-specific detection of bacterial nucleic acids using the sensor array approach was demonstrated both at 65 degrees C and at room temperature. These results demonstrate that molecular hybridization approaches can be adapted to rapid, room temperature conditions ideal for an electrochemical sensor array platform.
View details for DOI 10.1016/j.ymgme.2004.11.006
View details for Web of Science ID 000227173700012
View details for PubMedID 15639199
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Microelectromechanical systems in urology
UROLOGY
2003; 61 (5): 883-887
View details for DOI 10.1016/S0090-4295(03)00032-3
View details for Web of Science ID 000183040400001
View details for PubMedID 12735996
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Case scenario: 26-year-old male with right scrotal pain and swelling.
Reviews in urology
2002; 4 (1): 43-?
View details for PubMedID 16985652
View details for PubMedCentralID PMC1475959
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Pediatric urine testing
PEDIATRIC CLINICS OF NORTH AMERICA
2001; 48 (6): 1425-?
Abstract
Today, urinalysis is one of the most common clinical tests ordered for adult and pediatric patients. Because urine specimens are usually readily available and are obtained noninvasively, the urine testing is well suited for children. This article discusses the most common urine tests performed in children for screening purposes and also less common tests for diagnosis of specific disorders. Special considerations regarding urine specimen collection in children are discussed. Some simple tests that are underused by clinicians are mentioned, as are some exciting new molecular applications of urine testing.
View details for Web of Science ID 000172285000005
View details for PubMedID 11732123
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Coccidioidomycosis presenting as testicular mass
JOURNAL OF UROLOGY
2001; 166 (4): 1396-1396
View details for Web of Science ID 000170950100056
View details for PubMedID 11547090
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Sarcomatoid renal cell carcinoma: Biologic behavior, prognosis, and response to combined surgical resection and immunotherapy
JOURNAL OF CLINICAL ONCOLOGY
1999; 17 (2): 523-528
Abstract
Sarcomatoid variants of renal cell carcinoma (RCC) are aggressive tumors that respond poorly to immunotherapy. We report the outcomes of 31 patients with sarcomatoid RCC treated with a combination of surgical resection and immunotherapy.Patients were identified from the database of the University of California Los Angeles Kidney Cancer Program. We retrospectively reviewed the cases of 31 consecutive patients in whom sarcomatoid RCC was diagnosed between 1990 and 1997. Clinical stage, sites of metastasis, pathologic stage, and type of immunotherapy were abstracted from the medical records. The primary end point analyzed was overall survival, and a multivariate analysis was performed to distinguish any factors conferring an improved survivorship.Twenty-six percent of patients were male and 74% were female, and the median age was 59 years (range, 34 to 73 years). Length of follow-up ranged from 2 to 77 months (mean, 21.4 months). Twenty-eight patients (84%) had known metastases at the time of radical nephrectomy (67% had lung metastases and 40% had bone, 21% had liver, 33% had lymphatic, and 15% had brain metastases). Twenty-five patients (81%) received immunotherapy, including low-dose interleukin (IL)-2-based therapy (five patients), tumor-infiltrating lymphocyte-based therapy plus IL-2 (nine patients), high-dose IL-2-based therapy (nine patients), dendritic cell vaccine-based therapy (one patient), and interferon alpha-based therapy alone (one patient). Two patients (6%) achieved complete responses (median duration, 46+ months) and five patients (15%) achieved partial responses (median duration, 36 months). One- and 2-year overall survival rates were 48% and 37%, respectively. Using a multivariate analysis, age, sex, and percentage of sarcomatoid tumor (< or >50%) did not significantly correlate with survival. Improved survival was found in patients receiving high-dose IL-2 therapy compared with patients treated with surgery alone or any other form of immunotherapy (P = .025). Adjusting for age, sex, and percentage of sarcomatoid tumor, the relative risk of death was 10.4 times higher in patients not receiving high-dose IL-2 therapy. Final pathologic T stage did not correlate significantly with outcome, but node-positive patients had a higher death rate per year of follow-up than did the rest of the population (1.26 v 0.76, Cox regression analysis).Surgical resection and high-dose IL-2-based immunotherapy may play a role in the treatment of sarcomatoid RCCs in select patients.
View details for Web of Science ID 000078384500015
View details for PubMedID 10080595
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Pelvi-ureteric junction obstruction treated with Acucise (TM) retrograde endopyelotomy
BRITISH JOURNAL OF UROLOGY
1998; 82 (1): 8-11
Abstract
To determine the efficacy of retrograde endopyelotomy for the treatment of pelvi-ureteric junction (PUJ) obstruction using the Acucise ureteric balloon cutting catheter.Between February 1995 and July 1997, 13 consecutive patients with primary PUJ obstruction underwent Acucise endopyelotomy at our institution. The mean follow-up was 17.7 months (range 7-33). The success of the procedure was based on objective patency on follow-up diuretic isotopic renography and the subjective resolution of symptoms.The treatment was successful by objective criteria in eight of 13 patients and by subjective criteria in nine. The mean operative duration was 33 min (range 25-45) and all 13 patients were discharged within 24 h of the procedure. There were no major complications, such as vascular injury requiring transfusion. There were no delayed failures, as all failures occurred within 3 months of the procedure. Of the four total failures, two patients have successfully undergone open pyeloplasty and one other was found to have a crossing vessel at the lower pole at the time of the operation.In this small series. Acucise endopyelotomy was a safe procedure that offered effective, expeditious first-line treatment for PUJ obstruction. All failures occurred soon after treatment and did not hinder subsequent open pyeloplasty. Further studies with additional patients and a longer follow-up are warranted to determine the long-term efficacy of this promising new treatment.
View details for Web of Science ID 000074856900003
View details for PubMedID 9698655
- Chromophore assisted laser inactivation of cellular proteins Proc SPIE 1997; 2983: 30-6
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Isolation of a cDNA encoding a UV-damaged DNA binding factor defective in xeroderma pigmentosum group E cells
MUTATION RESEARCH-DNA REPAIR
1996; 362 (1): 105-117
Abstract
XPE binding factor (XPE-BF) is deficient in a subset of patients from xeroderma pigmentosum complementation group E. Binding activity copurifies with a 125 kDa polypeptide (p125) that binds to DNA damaged by ultraviolet (UV) radiation and many other agents. We isolated cDNA encoding a polypeptide with a predicted amino acid sequence that matched the sequences of eleven tryptic peptides derived from digestion of XPE-BF purified from human placenta. In vitro transcription and translation of the cDNA yielded a polypeptide of 125 kDa that bound specifically to UV-damaged DNA. Therefore the cDNA encodes either all or the major component of XPE-BF.
View details for Web of Science ID A1996TP86900012
View details for PubMedID 8538642
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CHROMOPHORE-ASSISTED LASER INACTIVATION OF SUBUNITS OF THE T-CELL RECEPTOR IN LIVING CELLS IS SPATIALLY RESTRICTED
PHOTOCHEMISTRY AND PHOTOBIOLOGY
1995; 62 (5): 923-929
Abstract
Chromophore-assisted laser inactivation (CALI) is a molecular photoablation technique that has been used to elucidate the in vivo roles of specific proteins in neural development. The interpretation of its effects on proteins in living cells relies on knowing how spatially restricted the CALI-induced damage is in vivo. To determine the spatial specificity of CALI in living cells, we have applied CALI to individual subunits of the T-cell receptor (TCR) complex on the surface of 2B4 hybridoma cells in culture and have examined the consequent structural and functional integrity of the TCR-alpha, TCR-beta and CD3-epsilon. The CALI of TCR-beta resulted in the disruption of the beta subunit and also resulted in a small effect on antibody binding alone to the neighboring TCR-alpha but caused no effect on another subunit, CD3-epsilon. Reciprocal experiments directing CALI to TCR-alpha and CD3-epsilon gave consistent results. No effects other than a simple loss of function were observed for any of these CALI experiments. These data demonstrate the extent of CALI-induced damage within a multisubunit complex in living cells and provide greater confidence for the future application of this technique to understanding in vivo function of proteins during complex cellular processes.
View details for Web of Science ID A1995TF81400018
View details for PubMedID 8570733
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CHROMOPHORE-ASSISTED LASER INACTIVATION OF PROTEINS IS MEDIATED BY THE PHOTOGENERATION OF FREE-RADICALS
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
1994; 91 (7): 2659-2663
Abstract
Chromophore-assisted laser inactivation (CALI) is a technique that selectively inactivates proteins of interest to elucidate their in vivo functions. This method has application to a wide array of biological questions and an understanding of its mechanism is required for its judicious application. We report here that CALI is not mediated by photoinduced thermal denaturation but by photogenerated free radicals. Thermal diffusion calculations suggest that the temperature changes resulting from CALI are too small to cause thermal denaturation, and Arrhenius plots of CALI are inconsistent with a photothermal mechanism. CALI shows an energy dose reciprocity above a threshold and can be inhibited by free-radical quenchers, thus demonstrating a photochemical mechanism of protein inactivation. The type of quenchers that are effective in inhibiting CALI indicates that the active species is a hydrogen abstractor which is not derived from molecular oxygen. We suggest that the active free-radical species is the hydroxyl radical and its very short lifetime explains the spatial specificity of CALI such that half-maximal damage is effected within 15 A from the dye moiety and no significant damage occurs at 34 A. The data are consistent with free-radical formation resulting from a sequential two-photon process.
View details for Web of Science ID A1994ND60200056
View details for PubMedID 8146171
View details for PubMedCentralID PMC43429
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SPATIAL SPECIFICITY OF CHROMOPHORE ASSISTED LASER INACTIVATION OF PROTEIN FUNCTION
BIOPHYSICAL JOURNAL
1992; 61 (4): 956-962
Abstract
Chromophore assisted laser inactivation (CALI) is a new technique that selectively inactivates proteins of interest to elucidate their in vivo functions. This method has application to a wide array of biological questions. An understanding of aspects of the mechanism of CALI is required for its judicious application. A critical concern for CALI is its spatial specificity because nonspecific inactivation of neighboring unbound proteins by CALI is a possibility. We show here that CALI is very dependent on the distance between the chromophore and the protein such that there is no significant effect beyond 60 A. CALI using antibodies can inactivate other proteins through a complex but its efficacy decreases approximately fourfold for each intervening protein. These data imply that CALI is spatially specific and damage to neighboring proteins is unlikely.
View details for Web of Science ID A1992HM25900012
View details for PubMedID 1581504
View details for PubMedCentralID PMC1260354
- Real time diagnosis of bladder cancer with probe-based confocal laser endomicroscopy Proc. SPIE 7902, 79021V (2011); doi:10.1117/12.874243
- Hybrid electrokinetic manipulation in high-conductivity media Lab Chip (DOI: 10.1039/C1LC20054B)