I was appointed the first holder of the Deborah E. Addicott – John A. Kriewall and Betsy A. Haehl Family Professor in Pediatrics in February 2007, and the Katie and Paul Dougherty Medical Director of Palliative Care in August 2010.
I was previously the Chairman of the Department of Pediatrics at Stanford University, where I was the Arline and Pete Harman Professor, and the Adalyn Jay Chief of Staff at Lucile Packard Children’s Hospital. I held these posts from 1993-2006 before stepping down to return to a career of clinical care, teaching, and research.
I obtained both his MD and PhD from Duke University in 1970, and was a pediatric intern at the Children’s Hospital in Boston from 1970-1971. After spending two years as a Staff Associate at the National Institutes of Health, I returned to Children’s Hospital in 1973 as a pediatric resident. I completed a fellowship in Pediatric Hematology/Oncology at Children’s Hospital and the Dana Farber Cancer Institute, and was named assistant, then associate, professor of pediatrics at Harvard Medical School.
In 1981, I was recruited to the University of Rochester School of Medicine and Dentistry where I was named the James P. Wilmot Associate Professor of Pediatric Oncology and Chief of the Division of Pediatric Oncology. I was promoted to Professor of Pediatrics in 1984 and Associate Chair for Research and Development in the Department of Pediatrics in 1987.
From 1985-1990, I was on the Scientific Advisory Board for St. Jude’s Children’s Research Hospital. I returned to the Board in 2000, and was its Chair from 2002 to 2006. I was also a member of the NIH Hematology II Study Section and was its Chair from 1987-1988. I served on the Board of Directors of Lucile Packard Children’s Hospital, and was a Board Member of the Ronald McDonald House and the Children’s Health Council in Palo Alto, California. I was a member of the Scientific Advisory Board of Montgomery Medical Venture Fund and Gamida Cell, a biotechnology company involved in expanded cord blood stem cells. I also served on the Steering and Selection Committees of the Pediatric Scientist Development Program, and I chair the Interdisciplinary Initiatives Program Committee of Bio-X, a venture into research, education, and innovation across all scientific communities of Stanford University. I was on the Board of Trustees of the March of Dimes, and served on its Executive Committee. I am currently a member of the Board of Trustees of the Morgridge Institute for Research, a private not-for-profit institute dedicated to supporting interdisciplinary medical research at the University of Wisconsin.
My research interests include: clinical trials in leukemia, mechanisms of drug resistance, and determining the roles of proteins in predicting susceptibility to, diagnosing, and treating childhood illnesses such as brain tumors, leukemia, prematurity, and inflammatory diseases. In addition, I am the medical director of the pediatric palliative care program at Lucile Packard Children’s Hospital, Stanford.
I married Ilene Cohen in 1965, before starting medical school at Duke. We are celebrating our 53rd wedding anniversary in August. Our sons, Philip, age 50, a lawyer, and Jonathan, age 49, an accountant, were born at Duke Hospital. They are both married, to Nicole and Renee, respectively. They live in the Philadelphia area, and each has given us two grandchildren (Sara, 22, Ethan, 20, Brooke, 17, and Bradley, 14), and much pleasure in our lives.
- Hematology, Pediatric
- Hematology/Oncology/Stem Cell Transplant, Pediatric
- Oncology (Cancer), Pediatric
- Pediatric Hematology-Oncology
- Pediatric Palliative Care
Chair, Stanford University School of Medicine - Pediatrics (1993 - 2006)
Medical Education:Duke University GME Training Verifications (1970) NC
Residency:Boston Children's Hospital (1976) MA
Residency:Boston Children's Hospital (1974) MA
Internship:Boston Children's Hospital (1971) MA
Current Research and Scholarly Interests
My research interests extend from hypothesis-driven studies in biochemistry and cell biology to discovery-driven interests in proteomics and systems biology to clinical treatment of acute lymphoblastic leukemia of children.
Our biochemical studies have centered on the identification and characterization of members of the glutathione peroxidase family of antioxidant enzymes that contain an enzymatically active selenocysteine residue within the primary structure of the protein.
Recently we have undertaken proteomic investigations whose aim is to identify differences in protein expression that may be biomarkers of diseases in children for which an unequivocal diagnostic test is unavailable, or there is little insight to the mechanism of the disease. This discovery-driven research is being used to identify proteins in plasma or urine of children with Kawasaki Disease, an inflammatory disorder that is the leading cause of acquired heart disease in the pediatric population. Other proteomic investigations are being performed in the areas of prematurity, neonatal disorders, acute lymphocytic and myelogenous leukemia, juvenile rheumatoid arthritis, and acquired respiratory distress syndromes.
My other clinical interests are found in hematologic and oncologic diseases of children, particularly acute lymphoblastic leukemia. Research is focused on optimization of multi-component chemotherapy and radiation treatment for these children. In addition, research investigations in pediatric palliative care have been initiated.
- Independent Studies (5)
Unique Molecular Patterns Uncovered in Kawasaki Disease Patients with Elevated Serum Gamma Glutamyl Transferase Levels: Implications for Intravenous Immunoglobulin Responsiveness
2016; 11 (12)
Resistance to intravenous immunoglobulin (IVIG) occurs in 10-20% of patients with Kawasaki disease (KD). The risk of resistance is about two-fold higher in patients with elevated gamma glutamyl transferase (GGT) levels. We sought to understand the biological mechanisms underlying IVIG resistance in patients with elevated GGT levels.We explored the association between elevated GGT levels and IVIG-resistance with a cohort of 686 KD patients (Cohort I). Gene expression data from 130 children with acute KD (Cohort II) were analyzed using the R square statistic and false discovery analysis to identify genes that were differentially represented in patients with elevated GGT levels with regard to IVIG responsiveness. Two additional KD cohorts (Cohort III and IV) were used to test the hypothesis that sialylation and GGT may be involved in IVIG resistance through neutrophil apoptosis.Thirty-six genes were identified that significantly explained the variations of both GGT levels and IVIG responsiveness in KD patients. After Bonferroni correction, significant associations with IVIG resistance persisted for 12 out of 36 genes among patients with elevated GGT levels and none among patients with normal GGT levels. With the discovery of ST6GALNAC3, a sialyltransferase, as the most differentially expressed gene, we hypothesized that sialylation and GGT are involved in IVIG resistance through neutrophil apoptosis. We then confirmed that in Cohort III and IV there was significantly less reduction in neutrophil count in IVIG non-responders.Gene expression analyses combining molecular and clinical datasets support the hypotheses that: (1) neutrophil apoptosis induced by IVIG may be a mechanism of action of IVIG in KD; (2) changes in sialylation and GGT level in KD patients may contribute synergistically to IVIG resistance through blocking IVIG-induced neutrophil apoptosis. These findings have implications for understanding the mechanism of action in IVIG resistance, and possibly for development of novel therapeutics.
View details for DOI 10.1371/journal.pone.0167434
View details for Web of Science ID 000392853100008
View details for PubMedID 28002448
View details for PubMedCentralID PMC5176264
A Classification Tool for Differentiation of Kawasaki Disease from Other Febrile Illnesses.
journal of pediatrics
2016; 176: 114-120 e8
To develop and validate a novel decision tree-based clinical algorithm to differentiate Kawasaki disease (KD) from other pediatric febrile illnesses that share common clinical characteristics.Using clinical and laboratory data from 801 subjects with acute KD (533 for development, and 268 for validation) and 479 febrile control subjects (318 for development, and 161 for validation), we developed a stepwise KD diagnostic algorithm combining our previously developed linear discriminant analysis (LDA)-based model with a newly developed tree-based algorithm.The primary model (LDA) stratified the 1280 subjects into febrile controls (n = 276), indeterminate (n = 247), and KD (n = 757) subgroups. The subsequent model (decision trees) further classified the indeterminate group into febrile controls (n = 103) and KD (n = 58) subgroups, leaving only 29 of 801 KD (3.6%) and 57 of 479 febrile control (11.9%) subjects indeterminate. The 2-step algorithm had a sensitivity of 96.0% and a specificity of 78.5%, and correctly classified all subjects with KD who later developed coronary artery aneurysms.The addition of a decision tree step increased sensitivity and specificity in the classification of subject with KD and febrile controls over our previously described LDA model. A multicenter trial is needed to prospectively determine its utility as a point of care diagnostic test for KD.
View details for DOI 10.1016/j.jpeds.2016.05.060
View details for PubMedID 27344221
View details for PubMedCentralID PMC5003696
A Novel Truncated Form of Serum Amyloid A in Kawasaki Disease
2016; 11 (6)
Kawasaki disease (KD) is an acute vasculitis in children that can cause coronary artery abnormalities. Its diagnosis is challenging, and many cytokines, chemokines, acute phase reactants, and growth factors have failed evaluation as specific biomarkers to distinguish KD from other febrile illnesses. We performed protein profiling, comparing plasma from children with KD with febrile control (FC) subjects to determine if there were specific proteins or peptides that could distinguish the two clinical states.Plasma from three independent cohorts from the blood of 68 KD and 61 FC subjects was fractionated by anion exchange chromatography, followed by surface-enhanced laser desorption ionization (SELDI) mass spectrometry of the fractions. The mass spectra of KD and FC plasma samples were analyzed for peaks that were statistically significantly different.A mass spectrometry peak with a mass of 7,860 Da had high intensity in acute KD subjects compared to subacute KD (p = 0.0003) and FC (p = 7.9 x 10-10) subjects. We identified this peak as a novel truncated form of serum amyloid A with N-terminal at Lys-34 of the circulating form and validated its identity using a hybrid mass spectrum immunoassay technique. The truncated form of serum amyloid A was present in plasma of KD subjects when blood was collected in tubes containing protease inhibitors. This peak disappeared when the patients were examined after their symptoms resolved. Intensities of this peptide did not correlate with KD-associated laboratory values or with other mass spectrum peaks from the plasma of these KD subjects.Using SELDI mass spectrometry, we have discovered a novel truncated form of serum amyloid A that is elevated in the plasma of KD when compared with FC subjects. Future studies will evaluate its relevance as a diagnostic biomarker and its potential role in the pathophysiology of KD.
View details for DOI 10.1371/journal.pone.0157024
View details for Web of Science ID 000377560200029
View details for PubMedID 27271757
View details for PubMedCentralID PMC4894573
Compassionate deactivation of ventricular assist devices in pediatric patients
JOURNAL OF HEART AND LUNG TRANSPLANTATION
2016; 35 (5): 564-567
Despite greatly improved survival in pediatric patients with end-stage heart failure through the use of ventricular assist devices (VADs), heart failure ultimately remains a life-threatening disease with a significant symptom burden. With increased demand for donor organs, liberalizing the boundaries of case complexity, and the introduction of destination therapy in children, more children can be expected to die while on mechanical support. Despite this trend, guidelines on the ethical and pragmatic issues of compassionate deactivation of VAD support in children are strikingly absent. As VAD support for pediatric patients increases in frequency, the pediatric heart failure and palliative care communities must work toward establishing guidelines to clarify the complex issues surrounding compassionate deactivation. Patient, family and clinician attitudes must be ascertained and education regarding the psychological, legal and ethical issues should be provided. Furthermore, pediatric-specific planning documents for use before VAD implantation as well as deactivation checklists should be developed to assist with decision-making at critical points during the illness trajectory. Herein we review the relevant literature regarding compassionate deactivation with a specific focus on issues related to children.
View details for DOI 10.1016/j.healun.2016.03.020
View details for Web of Science ID 000376951900004
View details for PubMedID 27197773
A Multi-Omics Analysis of Human Nucleus-Coded Mitochondrial Genes with Mouse Extraembryonic Tissue/Placenta Phenotypes: Implications in Mitochondria-Mediated Maternal and Fetal Complications.
SAGE PUBLICATIONS INC. 2016: 320A
View details for Web of Science ID 000372879200871
Urinary Colorimetric Sensor Array and Algorithm to Distinguish Kawasaki Disease from Other Febrile Illnesses
2016; 11 (2)
Kawasaki disease (KD) is an acute pediatric vasculitis of infants and young children with unknown etiology and no specific laboratory-based test to identify. A specific molecular diagnostic test is urgently needed to support the clinical decision of proper medical intervention, preventing subsequent complications of coronary artery aneurysms. We used a simple and low-cost colorimetric sensor array to address the lack of a specific diagnostic test to differentiate KD from febrile control (FC) patients with similar rash/fever illnesses.Demographic and clinical data were prospectively collected for subjects with KD and FCs under standard protocol. After screening using a genetic algorithm, eleven compounds including metalloporphyrins, pH indicators, redox indicators and solvatochromic dye categories, were selected from our chromatic compound library (n = 190) to construct a colorimetric sensor array for diagnosing KD. Quantitative color difference analysis led to a decision-tree-based KD diagnostic algorithm.This KD sensing array allowed the identification of 94% of KD subjects (receiver operating characteristic [ROC] area under the curve [AUC] 0.981) in the training set (33 KD, 33 FC) and 94% of KD subjects (ROC AUC: 0.873) in the testing set (16 KD, 17 FC). Color difference maps reconstructed from the digital images of the sensing compounds demonstrated distinctive patterns differentiating KD from FC patients.The colorimetric sensor array, composed of common used chemical compounds, is an easily accessible, low-cost method to realize the discrimination of subjects with KD from other febrile illness.
View details for DOI 10.1371/journal.pone.0146733
View details for Web of Science ID 000370038400003
View details for PubMedID 26859297
View details for PubMedCentralID PMC4747548
- Serological Targeted Analysis of an ITIH4 Peptide Isoform: A Preterm Birth Biomarker and Its Associated SNP Implications JOURNAL OF GENETICS AND GENOMICS 2015; 42 (9): 507-510
Cerebrospinal fluid protein dynamic driver network: At the crossroads of brain tumorigenesis
2015; 83: 36-43
To get a better understanding of the ongoing in situ environmental changes preceding the brain tumorigenesis, we assessed cerebrospinal fluid (CSF) proteome profile changes in a glioma rat model in which brain tumor invariably developed after a single in utero exposure to the neurocarcinogen ethylnitrosourea (ENU). Computationally, the CSF proteome profile dynamics during the tumorigenesis can be modeled as non-smooth or even abrupt state changes. Such brain tumor environment transition analysis, correlating the CSF composition changes with the development of early cellular hyperplasia, can reveal the pathogenesis process at network level during a time before the image detection of the tumors. In our controlled rat model study, matched ENU- and saline-exposed rats' CSF proteomics changes were quantified at approximately 30, 60, 90, 120, 150days of age (P30, P60, P90, P120, P150). We applied our transition-based network entropy (TNE) method to compute the CSF proteome changes in the ENU rat model and test the hypothesis of the critical transition state prior to impending hyperplasia. Our analysis identified a dynamic driver network (DDN) of CSF proteins related with the emerging tumorigenesis progressing from the non-hyperplasia state. The DDN associated leading network CSF proteins can allow the early detection of such dynamics before the catastrophic shift to the clear clinical landmarks in gliomas. Future characterization of the critical transition state (P60) during the brain tumor progression may reveal the underlying pathophysiology to device novel therapeutics preventing tumor formation. More detailed method and information are accessible through our website at http://translationalmedicine.stanford.edu.
View details for DOI 10.1016/j.ymeth.2015.05.004
View details for Web of Science ID 000358755100005
- Palliative care is critical to the changing face of child mortality and morbidity in the United States. Clinical pediatrics 2014; 53 (11): 1030-1031
Investigation of maternal environmental exposures in association with self-reported preterm birth.
2014; 45: 1-7
Identification of maternal environmental factors influencing preterm birth risks is important to understand the reasons for the increase in prematurity since 1990. Here, we utilized a health survey, the US National Health and Nutrition Examination Survey (NHANES) to search for personal environmental factors associated with preterm birth. 201 urine and blood markers of environmental factors, such as allergens, pollutants, and nutrients were assayed in mothers (range of N: 49-724) who answered questions about any children born preterm (delivery <37 weeks). We screened each of the 201 factors for association with any child born preterm adjusting by age, race/ethnicity, education, and household income. We attempted to verify the top finding, urinary bisphenol A, in an independent study of pregnant women attending Lucile Packard Children's Hospital. We conclude that the association between maternal urinary levels of bisphenol A and preterm birth should be evaluated in a larger epidemiological investigation.
View details for DOI 10.1016/j.reprotox.2013.12.005
View details for PubMedID 24373932
CSF protein dynamic driver network: at the crossroads of brain tumorigenesis
View details for Web of Science ID 000377412300186
Postinduction Dexamethasone and Individualized Dosing of Escherichia Coli L-Asparaginase Each Improve Outcome of Children and Adolescents With Newly Diagnosed Acute Lymphoblastic Leukemia: Results From a Randomized Study-Dana-Farber Cancer Institute ALL Consortium Protocol 00-01
JOURNAL OF CLINICAL ONCOLOGY
2013; 31 (9): 1202-1210
We assessed the toxicity and efficacy of dexamethasone and a novel dosing method of Escherichia coli L-asparaginase (EC-Asnase) in children and adolescents with newly diagnosed acute lymphoblastic leukemia (ALL).Patients achieving complete remission (CR) on Dana-Farber Cancer Institute ALL Consortium Protocol 00-01 were eligible for random assignment to 1) dexamethasone or prednisone, administered as 5-day pulses, every 3 weeks, and 2) weekly EC-Asnase, administered as a 25,000 IU/m(2) fixed dose (FD) or individualized dose (ID) starting at 12,500-IU/m(2), adjusted every 3 weeks based on nadir serum asparaginase activity (NSAA) determinations.Between 2000 and 2004, 492 evaluable patients (ages 1 to 18 years) enrolled; 473 patients (96%) achieved CR. Four hundred eight patients (86%) participated in the corticosteroid randomization and 384 patients (81%) in the EC-Asnase randomization. With 4.9 years of median follow-up, dexamethasone was associated with superior 5-year event-free survival (EFS; 90% v 81% for prednisone; P = .01) but higher rates of infection (P = .03) and, in older children, higher cumulative incidence of osteonecrosis (P = .02) and fracture (P = .06). ID EC-Asnase had superior 5-year EFS (90% v 82% for FD; P = .04), but did not reduce the frequency of asparaginase-related toxicity. Multivariable analysis identified both dexamethasone and ID EC-Asnase as independent predictors of favorable EFS.There was no overall difference in skeletal toxicity by corticosteroid type; dexamethasone was associated with more infections and, in older children, increased incidence of osteonecrosis and fracture. There was no difference in asparaginase-related toxicity by EC-Asnase dosing method. Dexamethasone and ID EC-Asnase were each associated with superior EFS. Monitoring NSAA during treatment with EC-Asnase may be an effective strategy to improve outcome in pediatric ALL.
View details for DOI 10.1200/JCO.2012.43.2070
View details for Web of Science ID 000316187600021
View details for PubMedID 23358966
View details for PubMedCentralID PMC3595424
Point-of-Care Differentiation of Kawasaki Disease from Other Febrile Illnesses
JOURNAL OF PEDIATRICS
2013; 162 (1): 183-U219
To test whether statistical learning on clinical and laboratory test patterns would lead to an algorithm for Kawasaki disease (KD) diagnosis that could aid clinicians.Demographic, clinical, and laboratory data were prospectively collected for subjects with KD and febrile controls (FCs) using a standardized data collection form.Our multivariate models were trained with a cohort of 276 patients with KD and 243 FCs (who shared some features of KD) and validated with a cohort of 136 patients with KD and 121 FCs using either clinical data, laboratory test results, or their combination. Our KD scoring method stratified the subjects into subgroups with low (FC diagnosis, negative predictive value >95%), intermediate, and high (KD diagnosis, positive predictive value >95%) scores. Combining both clinical and laboratory test results, the algorithm diagnosed 81.2% of all training and 74.3% of all testing of patients with KD in the high score group and 67.5% of all training and 62.8% of all testing FCs in the low score group.Our KD scoring metric and the associated data system with online (http://translationalmedicine.stanford.edu/cgi-bin/KD/kd.pl) and smartphone applications are easily accessible, inexpensive tools to improve the differentiation of most children with KD from FCs with other pediatric illnesses.
View details for DOI 10.1016/j.jpeds.2012.06.012
View details for Web of Science ID 000312915900040
View details for PubMedID 22819274
Identifying technical aliases in SELDI mass spectra of complex mixtures of proteins.
BMC research notes
2013; 6: 358-?
Biomarker discovery datasets created using mass spectrum protein profiling of complex mixtures of proteins contain many peaks that represent the same protein with different charge states. Correlated variables such as these can confound the statistical analyses of proteomic data. Previously we developed an algorithm that clustered mass spectrum peaks that were biologically or technically correlated. Here we demonstrate an algorithm that clusters correlated technical aliases only.In this paper, we propose a preprocessing algorithm that can be used for grouping technical aliases in mass spectrometry protein profiling data. The stringency of the variance allowed for clustering is customizable, thereby affecting the number of peaks that are clustered. Subsequent analysis of the clusters, instead of individual peaks, helps reduce difficulties associated with technically-correlated data, and can aid more efficient biomarker identification.This software can be used to pre-process and thereby decrease the complexity of protein profiling proteomics data, thus simplifying the subsequent analysis of biomarkers by decreasing the number of tests. The software is also a practical tool for identifying which features to investigate further by purification, identification and confirmation.
View details for DOI 10.1186/1756-0500-6-358
View details for PubMedID 24010718
View details for PubMedCentralID PMC3847147
Cloud-based solution to identify statistically significant MS peaks differentiating sample categories.
BMC research notes
2013; 6: 109-?
Mass spectrometry (MS) has evolved to become the primary high throughput tool for proteomics based biomarker discovery. Until now, multiple challenges in protein MS data analysis remain: large-scale and complex data set management; MS peak identification, indexing; and high dimensional peak differential analysis with the concurrent statistical tests based false discovery rate (FDR). "Turnkey" solutions are needed for biomarker investigations to rapidly process MS data sets to identify statistically significant peaks for subsequent validation.Here we present an efficient and effective solution, which provides experimental biologists easy access to "cloud" computing capabilities to analyze MS data. The web portal can be accessed at http://transmed.stanford.edu/ssa/.Presented web application supplies large scale MS data online uploading and analysis with a simple user interface. This bioinformatic tool will facilitate the discovery of the potential protein biomarkers using MS.
View details for DOI 10.1186/1756-0500-6-109
View details for PubMedID 23522030
View details for PubMedCentralID PMC3621609
Alterations in Cerebrospinal Fluid Proteins in a Presymptomatic Primary Glioma Model
2012; 7 (11)
Understanding the early relationship between brain tumor cells and their environment could lead to more sensitive biomarkers and new therapeutic strategies. We have been using a rodent model of neurocarcinogenesis in which all animals develop brain tumors by six months of age to establish two early landmarks in glioma development: the appearance of a nestin(+) cell at thirty days of age and the appearance of cellular hyperplasia between 60 and 120 days of age. We now report an assessment of the CSF proteome to determine the changes in protein composition that occur during this period.Nestin(+) cell clusters and microtumors were assessed in 63 ethylnitrosourea-exposed rats on 30, 60, and 90 days of age. CSF was obtained from the cisterna magna from 101 exposed and control rats at 30, 60, and 90 days and then analyzed using mass spectrometry. Differentially expressed peaks were isolated and identified.Nestin(+) cells were noted in all ethylnitrosourea-exposed rats assessed pathologically. Small microtumors were noted in 0%, 18%, and 67% of 30-, 60-, and 90-day old rats, respectively (p<0.05, Chi square). False Discovery Rate analysis of peak intensities showed that the number of true discoveries with p<0.05 increased markedly with increasing age. Isolation and identification of highly differentially detected proteins at 90 days of age revealed increases in albumin and a fragment of α1 macroglobulin and alterations in glutathionylated transthyretin.The presence of increased albumin, fragments of cerebrospinal fluid proteins, and glutathione breakdown in temporal association with the development of cellular hyperplasia, suggests that, similar to many other systemic cancers, inflammation and oxidative stress is playing an important early role in the host's response to brain tumor development and may be involved in affecting the early growth of brain tumor.
View details for DOI 10.1371/journal.pone.0049724
View details for Web of Science ID 000311333800047
View details for PubMedID 23185417
View details for PubMedCentralID PMC3501526
Identification of protein marker in vaginal wall tissues of women with stress urinary incontinence by protein chip array
JOURNAL OF OBSTETRICS AND GYNAECOLOGY RESEARCH
2012; 38 (1): 89-96
We sought to investigate protein biomarkers for stress urinary incontinence (SUI) in vaginal tissues using surface-enhanced laser desorption/ionization time-of-flight mass spectrometry (SELDI-TOF MS) and examine if this is a reliable methodology to examine proteins in small tissue specimens. We compared protein expression profile of vaginal tissue from women with SUI and continent controls. A 22.6kDa peak was identified by subsequent weak cation-exchange, reverse-phase fractionation, gel electrophoresis, and trypsin digestion, then analyzed by matrix assisted laser desorption/ionization mass spectrometry (MALDI MS) and MALDI MS-MS. Biomarker identity and expression level were confirmed by Western-blotting and immunohistochemistry.Expression of the 22.6kDa protein, identified as SM-22α, was significantly higher in women with SUI versus controls. A 3×3-mm tissue sample was sufficient for identification. Western-blot/immunohistochemistry confirmed the SELDI-TOS MS findings.SM-22α, a marker for myofibroblasts, was identified as a biomarker of SUI. Differential protein profiling by SELDI-TOF MS is a powerful and reliable tool for urogynecological research as it allows us to study an array of proteins simultaneously using small tissue samples.
View details for DOI 10.1111/j.1447-0756.2011.01690.x
View details for Web of Science ID 000298882800014
View details for PubMedID 22136672
View details for PubMedCentralID PMC3253185
A diagnostic algorithm combining clinical and molecular data distinguishes Kawasaki disease from other febrile illnesses
Kawasaki disease is an acute vasculitis of infants and young children that is recognized through a constellation of clinical signs that can mimic other benign conditions of childhood. The etiology remains unknown and there is no specific laboratory-based test to identify patients with Kawasaki disease. Treatment to prevent the complication of coronary artery aneurysms is most effective if administered early in the course of the illness. We sought to develop a diagnostic algorithm to help clinicians distinguish Kawasaki disease patients from febrile controls to allow timely initiation of treatment.Urine peptidome profiling and whole blood cell type-specific gene expression analyses were integrated with clinical multivariate analysis to improve differentiation of Kawasaki disease subjects from febrile controls.Comparative analyses of multidimensional protein identification using 23 pooled Kawasaki disease and 23 pooled febrile control urine peptide samples revealed 139 candidate markers, of which 13 were confirmed (area under the receiver operating characteristic curve (ROC AUC 0.919)) in an independent cohort of 30 Kawasaki disease and 30 febrile control urine peptidomes. Cell type-specific analysis of microarrays (csSAM) on 26 Kawasaki disease and 13 febrile control whole blood samples revealed a 32-lymphocyte-specific-gene panel (ROC AUC 0.969). The integration of the urine/blood based biomarker panels and a multivariate analysis of 7 clinical parameters (ROC AUC 0.803) effectively stratified 441 Kawasaki disease and 342 febrile control subjects to diagnose Kawasaki disease.A hybrid approach using a multi-step diagnostic algorithm integrating both clinical and molecular findings was successful in differentiating children with acute Kawasaki disease from febrile controls.
View details for DOI 10.1186/1741-7015-9-130
View details for Web of Science ID 000298862200001
View details for PubMedID 22145762
View details for PubMedCentralID PMC3251532
The low incidence of secondary acute myelogenous leukaemia in children and adolescents treated with dexrazoxane for acute lymphoblastic leukaemia: A report from the Dana-Farber Cancer Institute ALL Consortium
EUROPEAN JOURNAL OF CANCER
2011; 47 (9): 1373–79
Dexrazoxane reduces the risk of anthracycline-related cardiotoxicity. In a study of children with Hodgkin lymphoma, the addition of dexrazoxane may have been associated with a higher risk for developing second malignant neoplasms (SMNs) including acute myelogenous leukaemia (AML) and myelodysplastic syndrome (MDS). We determined the incidence of SMNs in children and adolescents with acute lymphoblastic leukaemia (ALL) who were treated with dexrazoxane.Between 1996 and 2010, the Dana-Faber Cancer Institute ALL Consortium conducted three consecutive multicentre trials for children with newly diagnosed ALL. In the first (1996-2000), high risk patients were randomly assigned to receive doxorubicin (30mg/m(2)/dose, cumulative dose 300mg/m(2)) preceded by dexrazoxane (300mg/m(2)/dose, 10 doses), or the same dose of doxorubicin without dexrazoxane, during induction and intensification phases. In subsequent trials (2000-2005 and 2005-2010), all high risk and very high risk patients received doxorubicin preceded by dexrazoxane. Cases of SMNs were collected prospectively and were pooled for analysis. The frequency and 5-year cumulative incidence (CI) of SMNs were determined for patients who had received dexrazoxane.Among 553 patients treated with dexrazoxane (1996-2000, N=101; 2000-2005, N=196; and 2005-2010, N=256), the number of SMNs observed by protocol was 0 (median follow-up 9.6years), 0 (median follow-up 5.2years), and 1 (median follow-up 2.1years). The only SMN was a case of AML, which developed in a patient with MLL-rearranged ALL 2.14years after initial diagnosis. The overall 5-year CI of SMNs for all 553 patients was 0.24±0.24%.In a large population of children with high risk ALL who received dexrazoxane as a cardioprotectant drug, the occurrence of secondary AML was a rare event.
View details for DOI 10.1016/j.ejca.2011.03.022
View details for Web of Science ID 000291907000012
View details for PubMedID 21514146
View details for PubMedCentralID PMC3736806
Assessment of dexrazoxane as a cardioprotectant in doxorubicin-treated children with high-risk acute lymphoblastic leukaemia: long-term follow-up of a prospective, randomised, multicentre trial
2010; 11 (10): 950–61
Doxorubicin chemotherapy is associated with cardiomyopathy. Dexrazoxane reduces cardiac damage during treatment with doxorubicin in children with acute lymphoblastic leukaemia (ALL). We aimed to establish the long-term effect of dexrazoxane on the subclinical state of cardiac health in survivors of childhood high-risk ALL 5 years after completion of doxorubicin treatment.Between January, 1996, and September, 2000, children with high-risk ALL were enrolled from nine centres in the USA, Canada, and Puerto Rico. Patients were assigned by block randomisation to receive ten doses of 30 mg/m² doxorubicin alone or the same dose of doxorubicin preceded by 300 mg/m² dexrazoxane. Treatment assignment was obtained through a telephone call to a centralised registrar to conceal allocation. Investigators were masked to treatment assignment but treating physicians and patients were not; however, investigators, physicians, and patients were masked to study serum cardiac troponin-T concentrations and echocardiographic measurements. The primary endpoints were late left ventricular structure and function abnormalities as assessed by echocardiography; analyses were done including all patients with data available after treatment completion. This trial has been completed and is registered with ClinicalTrials.gov, number NCT00165087.100 children were assigned to doxorubicin (66 analysed) and 105 to doxorubicin plus dexrazoxane (68 analysed). 5 years after the completion of doxorubicin chemotherapy, mean left ventricular fractional shortening and end-systolic dimension Z scores were significantly worse than normal for children who received doxorubicin alone (left ventricular fractional shortening: -0·82, 95% CI -1·31 to -0·33; end-systolic dimension: 0·57, 0·21-0·93) but not for those who also received dexrazoxane (-0·41, -0·88 to 0·06; 0·15, -0·20 to 0·51). The protective effect of dexrazoxane, relative to doxorubicin alone, on left ventricular wall thickness (difference between groups: 0·47, 0·46-0·48) and thickness-to-dimension ratio (0·66, 0·64-0·68) were the only statistically significant characteristics at 5 years. Subgroup analysis showed dexrazoxane protection (p=0·04) for left ventricular fractional shortening at 5 years in girls (1·17, 0·24-2·11), but not in boys (-0·10, -0·87 to 0·68). Similarly, subgroup analysis showed dexrazoxane protection (p=0·046) for the left ventricular thickness-to-dimension ratio at 5 years in girls (1·15, 0·44-1·85), but not in boys (0·19, -0·42 to 0·81). With a median follow-up for recurrence and death of 8·7 years (range 1·3-12·1), event-free survival was 77% (95% CI 67-84) for children in the doxorubicin-alone group, and 76% (67-84) for children in the doxorubicin plus dexrazoxane group (p=0·99).Dexrazoxane provides long-term cardioprotection without compromising oncological efficacy in doxorubicin-treated children with high-risk ALL. Dexrazoxane exerts greater long-term cardioprotective effects in girls than in boys.US National Institutes of Health, Children's Cardiomyopathy Foundation, University of Miami Women's Cancer Association, Lance Armstrong Foundation, Roche Diagnostics, Pfizer, and Novartis.
View details for DOI 10.1016/S1420-2045(10)70204-7
View details for Web of Science ID 000283210600021
View details for PubMedID 20850381
View details for PubMedCentralID PMC3756093
Extracellular glutathione peroxidase (Gpx3) binds specifically to basement membranes of mouse renal cortex tubule cells
AMERICAN JOURNAL OF PHYSIOLOGY-RENAL PHYSIOLOGY
2010; 298 (5): F1244-F1253
Glutathione peroxidase-3 (Gpx3), also known as plasma or extracellular glutathione peroxidase, is a selenoprotein secreted primarily by kidney proximal convoluted tubule cells. In this study Gpx3(-/-) mice have been produced and immunocytochemical techniques have been developed to investigate Gpx3 metabolism. Gpx3(-/-) mice maintained the same whole-body content and urinary excretion of selenium as did Gpx3(+/+) mice. They tolerated selenium deficiency without observable ill effects. The simultaneous knockout of Gpx3 and selenoprotein P revealed that these two selenoproteins account for >97% of plasma selenium. Immunocytochemistry experiments demonstrated that Gpx3 binds selectively, both in vivo and in vitro, to basement membranes of renal cortical proximal and distal convoluted tubules. Based on calculations using selenium content, the kidney pool of Gpx3 is over twice as large as the plasma pool. These data indicate that Gpx3 does not serve in the regulation of selenium metabolism. The specific binding of a large pool of Gpx3 to basement membranes in the kidney cortex strongly suggests a need for glutathione peroxidase activity in the cortical peritubular space.
View details for DOI 10.1152/ajprenal.00662.2009
View details for Web of Science ID 000276870800021
View details for PubMedID 20015939
View details for PubMedCentralID PMC2867408
Identification of Protein Marker in Vaginal Wall Tissues of Women with Stress Urinary Incontinence by Protein Chip Array
57th Annual Meeting of the Society-for-Gynecologic-Investigation
SAGE PUBLICATIONS INC. 2010: 275A–275A
View details for Web of Science ID 000275558601205
Intravenous PEG-asparaginase during remission induction in children and adolescents with newly diagnosed acute lymphoblastic leukemia
2010; 115 (7): 1351-1353
Over the past several decades, L-asparaginase, an important component of therapy for acute lymphoblastic leukemia (ALL), has typically been administered intramuscularly rather than intravenously in North America because of concerns regarding anaphylaxis. We evaluated the feasibility of giving polyethylene glycosylated (PEG)-asparaginase, the polyethylene glycol conjugate of Escherichia coli L-asparaginase, by intravenous infusion in children with ALL. Between 2005 and 2007, 197 patients (age, 1-17 years) were enrolled on Dana-Farber Cancer Institute ALL Consortium Protocol 05-01 and received a single dose of intravenous PEG-asparaginase (2500 IU/m(2)) over 1 hour during remission induction. Serum asparaginase activity more than 0.1 IU/mL was detected in 95%, 88%, and 7% of patients at 11, 18, and 25 days after dosing, respectively. Toxicities included allergy (1.5%), venous thrombosis (2%), and pancreatitis (4.6%). We conclude that intravenous administration of PEG-asparaginase is tolerable in children with ALL, and potentially therapeutic enzyme activity is maintained for at least 2 weeks after a single dose in most patients. This trial was registered at www.clinicaltrials.gov as #NCT00400946.
View details for DOI 10.1182/blood-2009-09-245951
View details for Web of Science ID 000274669200007
View details for PubMedID 20007809
View details for PubMedCentralID PMC2826760
Erwinia Asparaginase After Allergy to E. coli Asparaginase in Children With Acute Lymphoblastic Leukemia
PEDIATRIC BLOOD & CANCER
2010; 54 (2): 199-205
Escherichia coli asparaginase is an important component of treatment for childhood acute lymphoblastic leukemia (ALL); however, hypersensitivity develops in up to 30% of patients. We assessed the nadir enzyme activity and tolerability of Erwinia asparaginase, an alternative preparation, in E. coli asparaginase-allergic patients.Between 2000 and 2002, 215 children with newly diagnosed ALL were enrolled on Dana-Farber Cancer Institute ALL Consortium Protocol 00-01 and were to receive 30 weekly doses of intramuscular E. coli asparaginase. If E. coli asparaginase allergy developed, patients were switched to twice-weekly intramuscular Erwinia asparaginase (25,000 IU/m(2)). Nadir serum asparaginase activity (NSAA) was measured every 3 weeks.Forty-two patients (20%) developed E. coli asparaginase allergy and switched to Erwinia. Of 38 patients with evaluable samples, 34 (89%) Erwinia-treated patients had at least one therapeutic NSAA (> or =0.1 IU/ml). The median NSAA was 0.247 IU/ml 3 days and 0.077 IU/ml 4 days after an Erwinia dose. Associated toxicities included allergy in 14 (33%) and pancreatitis in 3 patients (7%). At a median follow-up of 5.4 years, event-free survival (+/-standard error) of the 42 patients who switched to Erwinia was 86 +/- 5% compared with 81 +/- 3% for the 170 patients without E. coli asparaginase allergy (P = 0.55).Twice-weekly Erwinia asparaginase was well tolerated and achieved a therapeutically effective NSAA in most E. coli asparaginase-allergic patients. Development of E. coli allergy and subsequent treatment with twice-weekly Erwinia did not adversely impact event-free survival. Erwinia asparaginase should be considered for E. coli asparaginase-allergic patients.
View details for DOI 10.1002/pbc.22225
View details for Web of Science ID 000273206700006
View details for PubMedID 19672973
View details for PubMedCentralID PMC3706086
Long-term results of Dana-Farber Cancer Institute ALL Consortium protocols for children with newly diagnosed acute lymphoblastic leukemia (1985-2000)
2010; 24 (2): 320-334
The Dana-Farber Cancer Institute (DFCI) acute lymphoblastic leukemia (ALL) Consortium has been conducting multi-institutional clinical trials in childhood ALL since 1981. The treatment backbone has included 20-30 consecutive weeks of asparaginase during intensification and frequent vincristine/corticosteroid pulses during the continuation phase. Between 1985 and 2000, 1457 children aged 0-18 years were treated on four consecutive protocols: 85-01 (1985-1987), 87-01 (1987-1991), 91-01 (1991-1955) and 95-01 (1996-2000). The 10-year event-free survival (EFS)+/-s.e. by protocol was 77.9+/-2.8% (85-01), 74.2+/-2.3% (87-01), 80.8+/-2.1% (91-01) and 80.5+/-1.8% (95-01). Approximately 82% of patients treated in the 1980s and 88% treated in the 1990s were long-term survivors. Both EFS and overall survival (OS) rates were significantly higher for patients treated in the 1990s compared with the 1980s (P=0.05 and 0.01, respectively). On the two protocols conducted in the 1990s, EFS was 79-85% for T-cell ALL patients and 75-78% for adolescents (age 10-18 years). Results of randomized studies revealed that dexrazoxane prevented acute cardiac injury without adversely affecting EFS or OS in high-risk (HR) patients, and frequently dosed intrathecal chemotherapy was an effective substitute for cranial radiation in standard-risk (SR) patients. Current studies continue to focus on improving efficacy while minimizing acute and late toxicities.
View details for DOI 10.1038/leu.2009.253
View details for Web of Science ID 000274397700007
View details for PubMedID 20016537
View details for PubMedCentralID PMC2820141
URINE PEPTIDOMICS FOR CLINICAL BIOMARKER DISCOVERY
ADVANCES IN CLINICAL CHEMISTRY, VOL 51
2010; 51: 181-213
Urine-based proteomic profiling is a novel approach that may result in the discovery of noninvasive biomarkers for diagnosing patients with different diseases, with the aim to ultimately improve clinical outcomes. Given new and emerging analytical technologies and data mining algorithms, the urine peptidome has become a rich resource to uncover naturally occurring peptide biomarkers for both systemic and renal diseases. However, significant analytical hurdles remain in sample collection and storage, experimental design, data analysis, and statistical inference. This study summarizes, focusing on our experiences and perspectives, the progress in addressing these challenges to enable high-throughput urine peptidomics-based biomarker discovery.
View details for DOI 10.1016/S0065-2423(10)51007-2
View details for Web of Science ID 000281865700007
View details for PubMedID 20857622
Effects of moderate versus deep hypothermic circulatory arrest and selective cerebral perfusion on cerebrospinal fluid proteomic profiles in a piglet model of cardiopulmonary bypass
JOURNAL OF THORACIC AND CARDIOVASCULAR SURGERY
2009; 138 (6): 1290-1296
Our objective was to compare protein profiles of cerebrospinal fluid between control animals and those subjected to cardiopulmonary bypass after moderate versus deep hypothermic circulatory arrest with selective cerebral perfusion.Immature Yorkshire piglets were assigned to one of four study groups: (1) deep hypothermic circulatory arrest at 18 degrees C, (2) deep hypothermic circulatory arrest at 18 degrees C with selective cerebral perfusion, (3) moderate hypothermic circulatory arrest at 25 degrees C with selective cerebral perfusion, or (4) age-matched control animals without surgery. Animals undergoing cardiopulmonary bypass were cooled to their assigned group temperature and exposed to 1 hour of hypothermic circulatory arrest. After arrest, animals were rewarmed, weaned off bypass, and allowed to recover for 4 hours. Cerebrospinal fluid collected from surgical animals after the recovery period was compared with cerebrospinal fluid from controls by surface-enhanced laser desorption/ionization time-of-flight mass spectrometry. Protein spectra were analyzed for differences between groups by Mann-Whitney U test and false discovery rate analysis.Baseline and postbypass physiologic parameters were similar in all surgical groups. A total of 194 protein peaks were detected. Compared with controls, groups 1, 2, and 3 had 64, 100, and 13 peaks that were significantly different, respectively (P < .05). Three of these peaks were present in all three groups. Cerebrospinal fluid protein profiles in animals undergoing cardiopulmonary bypass with moderate hypothermic circulatory arrest (group 3) were more similar to controls than either of the groups subjected to deep hypothermia.The mass spectra of cerebrospinal fluid proteins are altered in piglets exposed to cardiopulmonary bypass and hypothermic circulatory arrest. Moderate hypothermic circulatory arrest (25 degrees C) with selective cerebral perfusion compared with deep hypothermic circulatory arrest (18 degrees C) is associated with fewer changes in cerebrospinal fluid proteins, when compared with nonbypass controls.
View details for DOI 10.1016/j.jtcvs.2009.06.001
View details for Web of Science ID 000272029800004
View details for PubMedID 19660276
- Microfluidic Device for Coupling Capillary Electrophoresis and Matrix-Assisted Laser Desorption Ionization-Mass Spectrometry JALA 2009; 14 (5): 252-261
Plasma Biomarkers in a Mouse Model of Preterm Labor
2009; 66 (1): 11-16
Preterm labor (PTL) is frequently associated with inflammation. We hypothesized that biomarkers during pregnancy can identify pregnancies most at risk for development of PTL. An inflammation-induced mouse model of PTL was used. Surface-enhanced laser desorption/ionization time-of-flight mass spectrometry was used to analyze and compare the plasma protein (PP) profile between CD-1 mice injected intrauterine with either lipopolysaccharide (LPS) or PBS on d 14.5 of gestation. The median differences of normalized PP peaks between the two groups were determined using the Mann-Whitney U test and the false discovery rate. In a second series of experiments, both groups of mice were injected with a lower dose of LPS. A total of 1665 peaks were detected. Thirty peaks were highly differentially expressed (p < 0.0001) between the groups. Two 11 kDa protein peaks were identified by MALDI-TOF/TOF-MS and confirmed to be mouse serum amyloid A (SAA) 1 and 2. Plasma SAA2 levels were increased in LPS-treated animals compared with controls and in LPS-treated animals that delivered preterm vs. those that delivered at term. SAA2 has the potential to be a plasma biomarker that can identify pregnancies at risk for development of PTL.
View details for Web of Science ID 000267249300004
View details for PubMedID 19287348
FDR made easy in differential feature discovery and correlation analyses
2009; 25 (11): 1461-1462
Rapid progress in technology, particularly in high-throughput biology, allows the analysis of thousands of genes or proteins simultaneously, where the multiple comparison problems occurs. Global false discovery rate (gFDR) analysis statistically controls this error, computing the ratio of the number of false positives over the total number of rejections. Local FDR (lFDR) method can associate the corrected significance measure with each hypothesis testing for its feature-by-feature interpretation. Given the large feature number and sample size in any genomics or proteomics analysis, FDR computation, albeit critical, is both beyond the regular biologists' specialty and computationally expensive, easily exceeding the capacity of desktop computers. To overcome this digital divide, a web portal has been developed that provides bench-side biologists easy access to the server-side computing capabilities to analyze for FDR, differential expressed genes or proteins, and for the correlation between molecular data and clinical measurements.(http://translationalmedicine.stanford.edu/Mass-Conductor/FDR.html).
View details for DOI 10.1093/bioinformatics/btp176
View details for Web of Science ID 000266109500030
View details for PubMedID 19376824
- The rationale for early detection and treatment of brain tumors in survivors of childhood cancer ONCOLOGY REVIEWS 2009; 3 (1): 51–57
BIOMARKERS OF CEREBRAL INJURY IN A NEONATAL PIG MODEL OF CARDIOPULMONARY BYPASS AND CIRCULATORY ARREST AT 18 degrees C and 25 degrees C WITH AND WITHOUT SELECTIVE CEREBRAL PERFUSION
LIPPINCOTT WILLIAMS & WILKINS. 2009: 413
View details for Web of Science ID 000270092400930
Conducting a Qualitative Culture Study of Pediatric Palliative Care
16th International Congress on Care of the Terminally Ill
SAGE PUBLICATIONS INC. 2009: 5–16
While conducting a grounded theory study of Chinese American and Mexican American families' experiences in pediatric palliative care, we encountered a number of unanticipated challenges regarding project development, Institutional Review Boards, recruitment, data collection, and data analysis. In this article, we describe our experiences, strategies, and insights for the benefit of other researchers and clinicians in the field.
View details for DOI 10.1177/1049732308327346
View details for Web of Science ID 000261732300002
View details for PubMedID 19001106
Idiopathic neutropenia of childhood is associated with Fas/FasL expression
2008; 129 (3): 438-447
Idiopathic neutropenia (IN) in children is characterized by decreased neutrophil counts (<1500/microl), can be acute or chronic (greater than 6 months duration). The pathophysiology is not well understood; therefore, potential mechanisms of pediatric IN were investigated. An increase in Fas transcripts in neutrophils of IN patients compared to age-matched healthy control (HC) neutrophils was observed (p<0.005). Increased expression of Fas protein was found in IN neutrophils, while Fas surface expression on other immune cells was similar. Plasma from acute IN patients had higher protein levels of soluble FasL than chronic IN patients. When HC neutrophils were incubated in plasma from IN patients, greater rates of apoptosis were observed. Biochemical studies suggest the apoptotic factor(s) in plasma is heat-sensitive, non-IgG, and 12-50 kD protein. Addition of anti-sFasL blocking antibodies to patient plasma caused a statistically significant decrease in neutrophil apoptosis. These studies show that the Fas/FasL pathway could be associated with neutrophil apoptosis in childhood IN.
View details for DOI 10.1016/j.clim.2008.08.006
View details for Web of Science ID 000261011100007
View details for PubMedID 18819843
View details for PubMedCentralID PMC4161459
Capture of phosphopeptides using alpha-zirconium phosphate nanoplatelets
2008; 80 (14): 5542-5549
Alpha-zirconium phosphate nanoplatelets (alpha-ZrPN) were studied as a binding agent for phosphopeptides. Nanoplatelets of alpha-zirconium phosphate were incubated overnight with zirconium oxychloride, followed by centrifugation, and washed twice with water followed by an aqueous solution of 80% acetonitrile to form the binding agent. Alpha-ZrPN were able specifically to capture phosphoserine-containing peptides from a tryptic digest of a complex peptide mixture in which its abundance was only 0.05%. Alpha-ZrPN also bound peptides containing phosphothreonine and phosphotyrosine. The limit of detection for phosphopeptides is approximately 2 fmol, based on using matrix-assisted laser desorption/ionization mass spectrometry. Alpha-ZrPN were applied for the analysis of tryptic digests of mouse liver and leukemia cell phosphoproteomes and succeeded in identifying 158 phosphopeptides (209 phosphorylation sites) from 101 phosphoproteins in mouse liver lysate and 78 phosphopeptides (104 phosphorylation sites) from 59 phosphoproteins in leukemia cell extract. For these two tryptic digests, the alpha-ZrPN approach is able to capture more phosphopeptides than that obtained from TiO2 particles or from Fe(3+)-IMAC beads, but each method is able to bind some phosphopeptides that the others do not.
View details for DOI 10.1021/ac800577z
View details for Web of Science ID 000257598100036
View details for PubMedID 18522436
Absence of secondary malignant neoplasms in children with high-risk acute lymphoblastic leukemia treated with dexrazoxane
JOURNAL OF CLINICAL ONCOLOGY
2008; 26 (7): 1106–11
Dexrazoxane is a drug used to prevent anthracycline-induced cardiotoxicity. A recent report found an association between the use of dexrazoxane and the risk of developing secondary malignant neoplasms (SMNs) in children with Hodgkin's disease. We report the absence of an association of SMNs in children with acute lymphoblastic leukemia (ALL) treated on Dana-Farber Cancer Institute ALL Consortium Protocol 95-01.Two hundred five children with high-risk (HR) ALL were randomly assigned to receive doxorubicin alone (n = 100) or doxorubicin with dexrazoxane (n = 105) during the induction and intensification phases of multiagent chemotherapy. We compared incidence of SMNs in these two groups.With a median follow-up of 6.2 years, no differences in the incidence of SMNs were noted between the group that received dexrazoxane and the group that did not (P = .66). One SMN (a melanoma located outside of the cranial radiation field) occurred in a patient who was randomly assigned to doxorubicin alone. No SMNs were observed in patients randomly assigned to receive dexrazoxane.Dexrazoxane was not associated with an increased risk of SMNs in children treated for HR ALL. Given the potential importance of dexrazoxane as a cardioprotectant, we recommend that dexrazoxane continue to be used and studied in doxorubicin-containing pediatric regimens.
View details for DOI 10.1200/JCO.2007.12.2481
View details for Web of Science ID 000254178100015
View details for PubMedID 18309945
Biomarker clustering to address correlations in proteomic data
2007; 7 (7): 1037-1046
Correlated variables have been shown to confound statistical analyses in microarray experiments. The same effect applies to an even greater degree in proteomics, especially with the use of MS for parallel measurements. Biological effects such as PTM, fragmentation, and multimer formation can produce strongly correlated variables. The problem is compounded in some types of MS by technical effects such as incomplete chromatographic separation, binding to multiple surfaces, or multiple ionizations. Existing methods for dimension reduction, notably principal components analysis and related techniques, are not always satisfactory because they produce data that often lack clear biological interpretation. We propose a preprocessing algorithm that clusters highly correlated features, using the Bayes information criterion to select an optimal number of clusters. Statistical analysis of clusters, instead of individual features, benefits from lower noise, and reduces the difficulties associated with strongly correlated data. This preprocessing increases the statistical power of analyses using false discovery rate on simulated data. Strong correlations are often present in real data, and we find that clustering improves biomarker discovery in clinical SELDI-TOF-MS datasets of plasma from patients with Kawasaki disease, and bone-marrow cell extracts from patients with acute myeloid or acute lymphoblastic leukemia.
View details for DOI 10.1002/pmic.200600514
View details for Web of Science ID 000245739100003
View details for PubMedID 17390293
A potential biomarker in the cord blood of preterm infants who develop retinopathy of prematurity
2007; 61 (2): 215-221
Preterm infants are at risk of developing sepsis, necrotizing enterocolitis (NEC), chronic lung disease (CLD), and retinopathy of prematurity (ROP). We used high-throughput mass spectrometry to investigate whether cord blood proteins can be used to predict development of these morbidities. Cord blood plasma from 44 infants with a birth weight of <1500 g was analyzed by surface-enhanced laser desorption/ionization time-of-flight mass spectrometry (SELDI-TOF). Six infants developed ROP >or=stage II, 10 CLD, three sepsis, and one NEC. We detected 814 protein signals representing 330 distinct protein species. Nineteen biomarkers were associated with development of >or=stage II ROP [false-discovery rate (FDR) <5%] and none with CLD. Several proteins with molecular weight (Mr) 15-16 kD and pI 4-5 were detected with increased abundance in infants with ROP, while similar Mr proteins with pI 7-9 were less abundant in these patients. Sodium dodecylsulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and sequence analysis identified these proteins as alpha-, beta-, and gamma-globin chains. Partial deamidation of Asn139 in beta-globin chains was observed only in the pI 4-5 proteins. We conclude that there are several promising biomarkers for the risk of ROP. Deamidation of globin chains is especially promising and may indicate underlying prenatal pathologic mechanisms in ROP. Validation studies will be undertaken to determine their clinical utility.
View details for DOI 10.1203/pdr.0b013e31802d776d
View details for Web of Science ID 000243714700016
View details for PubMedID 17237725
Improving feature detection and analysis of surface-enhanced laser desorption/ionization-time of flight mass spectra
2005; 5 (11): 2778-2788
Discovering valid biological information from surface-enhanced laser desorption/ionization-time of flight mass spectrometry (SELDI-TOF MS) depends on clear experimental design, meticulous sample handling, and sophisticated data processing. Most published literature deals with the biological aspects of these experiments, or with computer-learning algorithms to locate sets of classifying biomarkers. The process of locating and measuring proteins across spectra has received less attention. This process should be tunable between sensitivity and false-discovery, and should guarantee that features are biologically meaningful in that they represent chemical species that can be identified and investigated. Existing feature detection in SELDI-TOF MS is not optimal for acquiring biologically relevant data. Most methods have so many user-defined settings that reproducibility and comparability among studies suffer considerably. To address these issues, we have developed an approach, called simultaneous spectrum analysis (SSA), which (i) locates proteins across spectra, (ii) measures their abundance, (iii) subtracts baseline, (iv) excludes irreproducible measurements, and (v) computes normalization factors for comparing spectra. SSA uses only two key parameters for feature detection and one parameter each for quality thresholds on spectra and peaks. The effectiveness of SSA is demonstrated by identifying proteins differentially expressed in SELDI-TOF spectra from plasma of wild-type and knockout mice for plasma glutathione peroxidase. Comparing analyses by SSA and CiphergenExpress Data Manager 2.1 finds similar results for large signal peaks, but SSA improves the number and quality of differences betweens groups among lower signal peaks. SSA is also less likely to introduce systematic bias when normalizing spectra.
View details for DOI 10.1002/pmic.200401184
View details for Web of Science ID 000231036100008
View details for PubMedID 15986333
Hospital staff and family perspectives regarding quality of pediatric palliative care
2004; 114 (5): 1248-1252
Development of a pediatric palliative care program was preceded by a needs assessment that included a staff survey and family interviews regarding improving pediatric palliative care.Four hundred forty-six staff members and community physicians responded to a written survey regarding comfort and expertise in delivering end of life care. Sixty-eight family members of 44 deceased children were interviewed regarding treatment, transition to palliative care, and bereavement follow-up contact. Frequencies were generated for responses to the staff survey. Five interviewers reviewed the families' narratives and identified frequently occurring themes.Staff members reported feeling inexperienced in communicating with patients and families about end of life issues, transition to palliative care, and do not resuscitate status. Families reported distress caused by uncaring delivery of bad news and careless remarks made by staff members. Staff members reported feeling inexperienced in symptom and pain management and described occasions when pain could have been better managed. Families believed pain had been managed as well as possible despite observing their children suffer. Fifty-four percent of staff members reported that adequate support was not provided for those who treat dying children. Staff members and family members stated their desire for more support. Staff members who described their most difficult experiences caring for a dying child referenced personal pain and inadequate support most frequently.Albeit from different perspectives, staff members and family members shared common concerns and experiences regarding pediatric palliative care. These experiences emphasize the need for additional systematic study, improved education and support for staff members, and continued development of more effective and compassionate delivery of pediatric palliative care.
View details for DOI 10.1542/peds.2003-0857-L
View details for Web of Science ID 000224842700008
View details for PubMedID 15520103
- Commentary on "Cancer incidence in adolescents and young adults in the United States, 1992-1997" JOURNAL OF ADOLESCENT HEALTH 2003; 32 (6): 403-404
Selenomethionine does not affect PSA secretion independent of its effect on LNCaP cell growth
2003; 54 (4): 315-321
Individuals supplemented with selenium have reduced incidence of prostate cancer. This study determines whether selenomethionine specifically affects the secretion of prostate specific antigen (PSA) in vitro.LNCaP cells were supplemented with selenomethionine for 7 days. PSA secretion was determined by ELISA. Cell proliferation was assessed by enumeration of trypan blue excluding cells. Colony formation was determined in soft agar. Cell cycle distribution was determined by FACS analysis of propidium iodide stained cells.Selenomethionine at > or = 70 microM inhibited LNCaP cell growth and colony formation. 0-100 microM selenomethionine did not affect the secretion of PSA by LNCaP cells in cell culture supernatants when normalized to the number of cells in culture. At supra-nutritional concentrations of selenomethionine, LNCaP cells had longer G(0)/G(1) phase in agreement with the inhibitory effects on cell growth.PSA secretion is not specifically inhibited by concentrations of selenomethionine corresponding to plasma selenium concentrations found in individuals supplemented with chemopreventive concentrations of selenized yeast. These data suggest that changes in serum PSA levels in individual patients during selenium supplementation is not an effect specific for PSA secretion, but rather may be a useful indicator for changes in disease progression in individual patients.
View details for DOI 10.1002/pros.10184
View details for Web of Science ID 000181056800009
View details for PubMedID 12539231
Extracellular glutathione peroxidase is secreted basolaterally by human renal proximal tubule cells
AMERICAN JOURNAL OF PHYSIOLOGY-RENAL PHYSIOLOGY
2002; 283 (1): F20-F28
Extracellular glutathione peroxidase (eGPx) is a secreted selenoenzyme with GPx activity. eGPx protein and activity are found in blood plasma and other extracellular fluids. eGPx in plasma is predominantly derived from the proximal tubules of kidneys in humans. Two types of human proximal tubule cells were cultured on semipermeable polycarbonate membranes to determine whether these cells secrete eGPx in a polarized direction. Immortalized human proximal tubule HK-2 cells and primary human proximal tubule cells formed confluent monolayers when cultured on these membrane inserts in culture dishes, as evidenced by transepithelial resistance. Both cell lines also constituted a barrier to diffusion of a fluoresceinated dextran of 75 kDa, a size similar to eGPx homotetramers. In both cell lines, 6- to 12-fold more 35S-methionine-labeled eGPx was immunoprecipitated from the basolateral media than from the apical media, indicating basolateral secretion of eGPx. eGPx was immunolocalized to the extracellular fluid at the basolateral surface of proximal tubules in human kidney. These data support the conclusion that eGPx is secreted through the basolateral membrane of human kidney proximal tubule cells into the extracellular fluid of the kidney, and from there enters blood plasma.
View details for DOI 10.1152/ajprenal.00014.2001
View details for Web of Science ID 000176138800003
View details for PubMedID 12060583
Increased expression of extracellular glutathione peroxidase in mice with dextran sodium sulfate-induced experimental colitis
2002; 51 (5): 641-646
Extracellular glutathione peroxidase (E-GPx) is a selenoenzyme that reduces hydrogen peroxide and organic peroxides. All plasma glutathione peroxidase (GPx) activity in humans is attributable to E-GPx. The gastrointestinal (GI) tract also synthesizes and secretes E-GPx into the extracellular milieu. Endogenously generated oxidants have been implicated in inflammatory bowel disease (IBD). We evaluated E-GPx levels in a mouse model of IBD using dextran sodium sulfate (DSS). Histologic lesions of the lower GI tract consisted of multifocal areas of mucosal erosion denuded of epithelial cells, reduction in goblet cells, dilated crypts, crypt collapse, submucosal edema, and transmural distribution of mixed inflammatory infiltrates. On d 7, plasma GPx activity in the DSS group increased by 61% compared with the control group (p < 0.05). Western blot analysis demonstrated a 64% increase in E-GPx protein in the plasma of the DSS group after 7 d of treatment (p < 0.01). As the major source of plasma GPx is the kidney, we determined whether the increase in plasma GPx activity and protein was caused by a change in E-GPx synthesis by the kidney. After 3 and 7 d of DSS treatment, E-GPx mRNA levels, relative to glyceraldehyde-3-phosphate dehydrogenase, increased in the kidney (p < 0.05) without a concomitant increase in cellular GPx mRNA on d 7. These results suggest that the inflammatory injury in the intestine elicits an increase in E-GPx in the plasma that is associated with an increase in E-GPx mRNA in the kidney. This implies that renal production of E-GPx may be sensitive to insults distal to the kidney.
View details for Web of Science ID 000175171600016
View details for PubMedID 11978890
Developmental stage-specific expression of the alpha and beta subunits of the HIF-1 protein in the mouse and human fetus
MOLECULAR GENETICS AND METABOLISM
2002; 75 (3): 244-249
Erythropoietin (Epo) is a glycoprotein hormone that is the primary regulator of erythropoiesis. Transcription of the Epo gene increases in response to hypoxia or anemia. Epo is synthesized in the liver in fetal life and in the kidney later in gestation. In the mammalian fetus the switch in Epo production from the liver to the kidney occurs in the third trimester. Hypoxia-inducible factor (HIF-1) is a heterodimeric transcription factor consisting of an alpha and beta subunit that binds under hypoxic conditions to an enhancer element in the 3' region of the Epo gene. In order to determine if there is a relationship between expression of HIF-1 alpha and beta subunits with the shift in expression of the Epo gene from the liver to the kidney or with the transitional events occurring at birth we analyzed the expression of these mRNAs in mouse and human fetuses at different stages of gestation. Total RNA was extracted from the brain, heart, kidney, liver, and lungs of mice at P15, P17, and P19 of gestation, from newborn mice at Days 1 and 3, from an adult and an anemic adult mouse as well as from human fetuses at 14-22 weeks of gestation. RNA was analyzed by Northern blot and slot-blot hybridization using appropriate cDNA probes. HIF-1alpha and -beta mRNA were expressed in all tissues tested and at all stages of gestation in the mouse and human fetus. Expression of HIF-1alpha and -beta in the mouse fetus was highest in the brain followed by heart, kidney, lung, and liver. Expression in the fetal and newborn mice was higher versus the adult and expression was higher in the anemic versus the normal adult mouse. In the human fetus a higher expression of HIF-1alpha was noted in the brain followed by heart, kidney, lung, and liver. There was a small trend toward a decrease in expression with advancing gestational age. HIF-1beta was expressed to a similar extent in all human tissues examined. Our studies indicate that expression of HIF-1alpha and -beta subunits was not related to the switch in Epo gene expression from the liver to the kidney. Although expression of HIF-1alpha and -beta did not decrease immediately after birth, it is possible that the HIF-1 protein is involved in the various events that occur during transition after birth.
View details for DOI 10.1006/mgme.2001.3293
View details for Web of Science ID 000174740300007
View details for PubMedID 11914036
Family perspectives on the quality of pediatric palliative care
ARCHIVES OF PEDIATRICS & ADOLESCENT MEDICINE
2002; 156 (1): 14-19
As a prelude to establishing a Pediatric Palliative Care Program, we solicited information from families about their experiences and their suggestions for improving the quality of end-of-life care. Participants were English- and Spanish-speaking family members of deceased pediatric patients who received care at Lucile Salter Packard Children's Hospital, Stanford University Medical Center, Palo Alto, Calif.Sixty-eight family members of 44 deceased children were interviewed regarding treatment, transition to palliative care, and bereavement follow-up. Four clinical social workers and one clinical psychologist reviewed the participants' responses and identified frequently occurring themes.Several areas of unsatisfactory interactions with staff were identified: confusing, inadequate, or uncaring communications regarding treatment or prognosis; preventable oversights in procedures or policies; failure to include or meet the needs of siblings and Spanish-speaking family members; and inconsistent bereavement follow-up. A discrepancy emerged between the high degree of pain described by the families and parents' perceptions that pain had been managed well. Community hospice programs are frequently poorly prepared to serve pediatric patients.There is a need to improve pediatric palliative care. Recurring themes in the family interviews suggest useful issues to consider in the development of a palliative care program.
View details for Web of Science ID 000173079600005
View details for PubMedID 11772185
Intracellular reduction of selenite into glutathione peroxidase. Evidence for involvement of NADPH and not glutathione as the reductant
MOLECULAR AND CELLULAR BIOCHEMISTRY
2000; 211 (1-2): 9-17
Selenium (Se) in selenite is present in an oxidized state, and must be reduced for it to be incorporated as selenocysteine into selenoenzymes such as glutathione peroxidase (GPx). In vitro, Se, as in selenite, can be reduced utilizing glutathione (GSH) and glutathione reductase (GRed). We determined the effects of decreasing GSH levels, inhibiting GRed activity, and decreasing cellular NADPH on the selenite-dependent rate of GPx synthesis in cultured cells: PC3, CHO, and the E89 glucose-6-phosphate dehydrogenase (G-6-PD)-deficient cell line. A novel statistical analysis method was developed (using Box Cox transformed regression and a bootstrap method) in order to assess the effects of these manipulations singly and in combinations. Buthionine sulfoximine (BSO) was used to decrease GSH levels, 1,3 bis-(2 chloroethyl)-1 -nitrosourea (BCNU) was used to inhibit GRed activity and methylene blue (MB) was used to decrease cellular NADPH levels. This statistical method evaluates the effects of BSO, BCNU, MB and selenite alone and in combinations on GPx activity. Decreasing the GSH level (< 5% of control) did not have an effect on the selenite-dependent rate of GPx synthesis in PC3 or CHO cells, but did have a small inhibitory effect on the rate of GPx synthesis in E89 cells. Inhibiting GRed activity was also associated with either no effect (CHO, E89) or a small effect (PC3) on GPx activity. In contrast, decreasing NADPH levels in cells treated with MB was associated with a large decrease in the selenite-dependent rate of GPx synthesis to 36, 34 and 25% of control in PC3, CHO, and E89 cells, respectively. The effects of BSO plus BCNU were not synergistic in any of the cell lines. The effects of BSO plus MB were synergistic in G-6-PD-deficient E89 cells, but not in PC3 or CHO cells. We therefore conclude that under normal culture conditions, NADPH, and not glutathione, is the primary reductant of Se in selenite to forms that are eventually incorporated into GPx. For cells with abnormal ability to generate NADPH, lowering the GSH levels had a small effect on selenite-dependent GPx synthesis. GRed activity is not required for the selenite-dependent synthesis of GPx.
View details for Web of Science ID 000089137800002
View details for PubMedID 11055542
Increase in extracellular glutathione peroxidase in plasma and lungs of mice exposed to hyperoxia
1999; 46 (6): 715-721
Extracellular glutathione peroxidase (E-GPx) is a selenium-dependent enzyme that can reduce hydrogen peroxide and phospholipid hydroperoxides. E-GPx is found in plasma and extracellular fluids such as bronchoalveolar lavage fluid. Because lung is one of the tissues that is capable of synthesizing and secreting E-GPx, the effect of exposure to hyperoxia on E-GPx in plasma and lung were studied in an injury model of hyperoxia exposure in adult mice. Exposure to 100% oxygen for 72 h resulted in an increase of 55% in plasma GPx activity and an increase of 50% in the amount of E-GPx protein in the plasma. Exposure to hyperoxia was also associated with an increase in the amount of E-GPx protein in lungs. The 7-fold increase in the amount of E-GPx protein in lungs was not due to plasma contamination of lungs from mice exposed to hyperoxia. E-GPx in the lung is calculated to account for 10% of lung GPx activity in control mice. However, E-GPx is calculated to account for 45% of lung GPx activity in the lungs of mice exposed to hyperoxia for 72 h. Further studies are needed to determine whether the increase in lung E-GPx is due to changes in translation or stability of E-GPx. The role of E-GPx in protecting the lung from oxidative damage warrants further study.
View details for Web of Science ID 000083870200013
View details for PubMedID 10590029
Expression of extracellular glutathione peroxidase in human and mouse gastrointestinal tract
AMERICAN JOURNAL OF PHYSIOLOGY-GASTROINTESTINAL AND LIVER PHYSIOLOGY
1998; 275 (6): G1463-G1471
Extracellular glutathione peroxidase (EGPx) is a glycosylated selenoprotein capable of reducing hydrogen peroxide, organic hydroperoxides, free fatty acid hydroperoxides, and phosphatidylcholine hydroperoxides. We found that human large intestinal explant cultures synthesize EGPx and cellular glutathione peroxidase (CGPx) and secrete EGPx. The level of EGPx mRNA expression relative to alpha-tubulin was similar throughout the mouse gastrointestinal tract. EGPx mRNA transcripts have been localized to mature absorptive epithelial cells in human and mouse large intestine. Western blot analysis of mouse intestinal protein has demonstrated the presence of EGPx protein in the small intestine, cecum, and large intestine, with the highest protein levels found in the cecum. Immunohistochemistry studies of human large intestine and mouse small and large intestine sections demonstrated the presence of EGPx protein within mature absorptive epithelial cells. In human large intestine and mouse small intestine, EGPx protein is also present in the extracellular milieu. These results suggest a role for EGPx in protection of the intestinal tract from peroxidative damage and/or in intercellular metabolism of peroxides.
View details for Web of Science ID 000077746400031
View details for PubMedID 9843785
Plasma glutathione peroxidase and its relationship to renal proximal tubule function
MOLECULAR GENETICS AND METABOLISM
1998; 65 (3): 238-245
Selenium-dependent extracellular glutathione peroxidase (E-GPx) is found in plasma and other extracellular fluids. Previous studies have indicated that patients with chronic renal failure on dialysis have low plasma GPx activity. In this study, dialysis patients had approximately 40% of control plasma GPx activity, while anephric individuals had lowest plasma GPx activities ranging from 2 to 22% of control. The residual plasma GPx activity in anephric individuals could be completely precipitated by anti-E-GPx antibodies, indicating that all plasma GPx activity can be attributed to E-GPx in both normal and anephric individuals. Plasma GPx activity rises rapidly following kidney transplantation, often reaching normal values within 10 days. The plasma GPx activity in some transplanted patients rises to levels higher than the normal range, followed by a return to the normal range. Since E-GPx in the kidney is primarily synthesized in the proximal tubules, we investigated whether nephrotoxic agents known to disrupt proximal tubule function also affected plasma GPx activity. The beta-lactam antibiotic cephaloglycin rapidly caused a decrease in plasma GPx activity in rabbits. In addition, the chemotherapeutic agent ifosfamide caused a decrease in plasma GPx activity in pediatric osteosarcoma patients. Fanconi syndrome associated with either ifosfamide therapy or valproic acid therapy also caused a decrease in plasma GPx activity. Thus plasma GPx activity is related to kidney function and is decreased in certain situations where nephrotoxic drugs are administered. Monitoring plasma GPx activity may have predictive value in evaluating the function of transplanted kidneys or in predicting those patients particularly at risk of nephrotoxic injury associated with certain medications.
View details for Web of Science ID 000077722800008
View details for PubMedID 9851889
Serologic markers to monitor the engraftment, growth, and treatment response of human leukemias in severe combined immunodeficient mice
1996; 87 (10): 4325-4332
We have investigated human lactate dehydrogenase (LDH) isoenzymes and human nuclear matrix protein 41/7 (NMP 41/7) as potential serologic markers to monitor the course of human leukemia in severe combined immunodeficient (SCID) mice. Following the transplantation of 10(6) human acute lymphoblastic leukemia (ALL) Nalm-6 cells, human specific LDH isoenzymes were measurable in the serum of SCID mice as early as 7 days after transplantation, although serum total LDH increased in some animals as early as 5 days after transplantation. Human NMP 41/7 was measurable in all animals at day 15 after leukemia cell injection. Serum levels of total LDH, human specific LDH and NMP 41/7 increased progressively over time, reaching total LDH levels as high as 50,000 U/L at day 25 after transplantation. To determine whether the levels of LDH and NMP 41/7 in serum were a reflection of human tumor burden, we studied these serologic markers in SCID mice bearing measurable subcutaneous human neuroblastoma tumors, or compared the serum levels of these markers with the number of human leukemia CD10+ cells in the bone marrow of the SCID mice. The serum levels of total LDH, human specific LDH isoenzymes, and NMP 41/7 correlated well with tumor burden, and they drastically decreased or disappeared from serum after the human leukemia or neuroblastoma cells were selectively killed with a single intravenous (IV) injection of 1 to 3 micrograms diphtheria toxin (DT) (the cellular receptor for DT is present on human cells, but not on mouse cells). Paraplegic mice with central nervous system leukemia completely recovered after DT treatment. We conclude that measurements of serum levels of total LDH, human LDH isoenzymes, and NMP 41/7 are sensitive, quantitative, rapid, and easy to perform serologic methods useful to monitor the engraftment, progression, and treatment response of human leukemia in SCID mice.
View details for Web of Science ID A1996UK87900035
View details for PubMedID 8639792
- 1995 Public policy plenary symposium: ''The Crisis in Clinical Research'' PEDIATRIC RESEARCH 1996; 39 (5): 902-913
EXTRACELLULAR GLUTATHIONE-PEROXIDASE MESSENGER-RNA AND PROTEIN IN HUMAN CELL-LINES
ARCHIVES OF BIOCHEMISTRY AND BIOPHYSICS
1994; 309 (2): 239-246
Extracellular glutathione peroxidase (E-GPx) and cellular glutathione peroxidase (C-GPx) are selenoenzymes encoded by two distinct genes. Using specific immunoprecipitations of [75Se]selenium metabolically labeled human cell lines in culture, it was found that Caco-2, Hep3B, Hep G2, and Caki-2 synthesize C-GPx and E-GPx and secrete E-GPx. HBL-100, BT-20, and MCF-7 synthesize only C-GPx. The relationship between Se status (as determined by C-GPx activity) and E-GPx and C-GPx mRNA steady-state levels was investigated in Hep G2, Caco-2, and Caki-2. The most Se-deficient Hep G2, Caco-2, and Caki-2 cells had 8.7 +/- 2.6, 11.2 +/- 4.9, and 9.4 +/- 5.0%, respectively, of C-GPx activity of the replete cells. The steady-state levels of mRNA were measured by Northern and slot blot hybridization analysis. By Northern analysis, a single band was present at 1.0 and 1.80 kb for C-GPx and E-GPx mRNA, respectively, in all three cell lines. Scanning densitometry of the blots revealed that the most Se-deficient cells had 30-50% C-GPx mRNA and 60-80% E-GPx mRNA of the replete cells. It is concluded that, in addition to previously examined human cell lines, Hep3B and Caco-2 make and secrete E-GPx while HBL-100 and BT-20 do not. The slightly reduced levels of G-GPx and E-GPx mRNA in Se-deficient human cell lines can only partially account for the decreased C-GPx activity in Se-deficient human cell lines.
View details for Web of Science ID A1994MY85800006
View details for PubMedID 8135533
HUMAN KIDNEY PROXIMAL TUBULES ARE THE MAIN SOURCE OF PLASMA GLUTATHIONE-PEROXIDASE
AMERICAN JOURNAL OF PHYSIOLOGY
1994; 266 (2): C367-C375
The sites of synthesis of extracellular (E) glutathione peroxidase (GPX), a unique selenoglycoprotein present in plasma, are not known. To investigate the possibility that the kidney is the main source for the plasma GPX, we examined GPX activities and selenium concentrations in the plasma of patients with renal failure on dialysis and nephrectomized patients before and after kidney transplantation. Plasma GPX activities in these patients were 42, 22, and 180% of normal EGPX activity, respectively, whereas plasma Se levels were within the normal range. Twenty-four hours after nephrectomy of anesthetized rats, plasma GPX activity was 30.0 +/- 6.4% of the activity at zero time. Northern hybridization analysis of eight human tissues probed with EGPX and cellular glutathione peroxidase (CGPX) cDNA revealed that the ratio of EGPX to CGPX was highest in the kidney. cRNA in situ hybridization studies on kidney slices showed that only proximal tubular epithelial cells and parietal epithelial cells of Bowman's capsule contained EGPX transcripts. Caki-2, a proximal tubular renal carcinoma cell line, makes and actively secretes EGPX. Taken together, these results strongly suggest that kidney proximal tubular cells are the main source for GPX activity in the plasma.
View details for Web of Science ID A1994NA80100006
View details for PubMedID 8141250
COMPARATIVE PHARMACOKINETIC STUDIES OF 3 ASPARAGINASE PREPARATIONS
JOURNAL OF CLINICAL ONCOLOGY
1993; 11 (9): 1780-1786
As part of pharmacologic studies of asparaginase (ASNase), we determined the half-life of ASNase activity and protein, and the effect of dose, repeated doses, different drug preparations, and hypersensitivity reactions on the half-life (t1/2) of serum ASNase activity.We measured ASNase activity (spectrophotometric assay) in serum samples obtained from patients with acute lymphoblastic leukemia (ALL) at various times during their therapy with intramuscular ASNase. ASNase protein was measured by enzyme-linked immunoadsorbent assay (ELISA).Studies following the initial dose of Escherichia coli-derived ASNase demonstrated no difference in apparent t1/2 following 25,000 IU/m2 versus 2,500 IU/m2 (1.24 v 1.35 days, P = .2). The apparent t1/2s following maintenance doses of E coli ASNase (middle dose t1/2, 1.28 days, or last dose t1/2, 1.14 days) showed no difference when compared with the initial dose of ASNase (P = .3 to .9). There was no significant difference between the apparent t1/2s of ASNase activity and ASNase protein (n = 8, P = .2 to .6). The serum t1/2 was 0.65 and 5.73 days for patients receiving Erwinia or polyethylene glycol (PEG)-modified E coli ASNase, respectively, as the induction dose. ASNase activity was undetectable in sera of four patients studied in the week following an anaphylactic reaction to E coli ASNase and the t1/2 was significantly shorter in five patients with a history of allergic reaction to E coli ASNase who were studied following a dose of PEG ASNase, (t1/2, 1.80 days).We conclude that (1) the apparent t1/2 of ASNase is dependent on enzyme preparation used, but is not affected by dose or by repeated use; (2) the apparent t1/2 of E coli ASNase as a protein is the same as the apparent t1/2 of enzymatic activity; and (3) patients who have had a hypersensitivity reaction to E coli ASNase have a decreased apparent t1/2 with both E coli and PEG ASNase.
View details for Web of Science ID A1993LW36900021
View details for PubMedID 8355045