Dora Ho

All Publications

• Managing infectious challenges in the age of molecular-targeted therapies for adult hematological malignancies. Transplant infectious disease : an official journal of the Transplantation Society Shah, M., El Chaer, F., Ho, D. Y., El Boghdadly, Z. 2024: e14283

  Abstract

  Over the last decade, the therapeutic landscape for hematological malignancies (HMs) has witnessed a remarkable surge in the development of novel biological and small-molecule-targeted immunomodulatory agents. These therapies have drastically improved survival, but some come at the cost of increased risk of bacterial, viral, and/or fungal infections and on-target off-tumor immunological side effects. To mitigate such risks, physicians must be well informed about infectious complications and necessary preventive measures, such as screening, vaccinations, and antimicrobial prophylaxis. Furthermore, physicians should be vigilant about the noninfectious side effects of these agents that can mimic infections and understand their potential drug-drug interactions with antimicrobials. Strengthening and harmonizing the current surveillance and reporting system for drug-associated infections in real-world settings is essential to better ascertain the potential infections associated with these agents. In this review, we aimed to summarize the infection risks associated with novel agents used for specific HMs and outline recommended strategies for monitoring and prophylaxis.

  View details for DOI 10.1111/tid.14283

  View details for PubMedID 38698640

• Dynamics and prognostic value of plasma cell-free DNA PCR in patients with invasive aspergillosis and mucormycosis. Journal of clinical microbiology Moreno, A., Mah, J., Budvytiene, I., Ho, D. Y., Schwenk, H. T., Banaei, N. 2024: e0039424

  Abstract

  Aspergillus species and Mucorales agents are the primary etiologies of invasive fungal disease (IFD). Biomarkers that predict outcomes are needed to improve care. Patients diagnosed with invasive aspergillosis and mucormycosis using plasma cell-free DNA (cfDNA) PCR were retested weekly for 4 weeks. The primary outcome included all-cause mortality at 6 weeks and 6 months based on baseline cycle threshold (CT) values and results of follow-up cfDNA PCR testing. Forty-five patients with Aspergillus and 30 with invasive Mucorales infection were retested weekly for a total of 197 tests. Using the European Organization for Research and Treatment of Cancer and the Mycoses Study Group Education and Research Consortium (EORTC/MSG) criteria, 30.7% (23/75), 25.3% (19/75), and 38.7% (29/75) had proven, probable, and possible IFD, respectively. In addition, 97.3% (73/75) were immunocompromised. Baseline CT increased significantly starting at week 1 for Mucorales and week 2 for Aspergillus. Aspergillosis and mucormycosis patients with higher baseline CT (CT >40 and >35, respectively) had a nonsignificantly higher survival rate at 6 weeks, compared with patients with lower baseline CT. Mucormycosis patients with higher baseline CT had a significantly higher survival rate at 6 months. Mucormycosis, but not aspergillosis patients, with repeat positive cfDNA PCR results had a nonsignificantly lower survival rate at 6 weeks and 6 months compared with patients who reverted to negative. Aspergillosis patients with baseline serum Aspergillus galactomannan index <0.5 and <1.0 had significantly higher survival rates at 6 weeks when compared with those with index ≥0.5 and ≥1.0, respectively. Baseline plasma cfDNA PCR CT can potentially be used to prognosticate survival in patients with invasive Aspergillus and Mucorales infections.We show that Aspergillus and Mucorales plasma cell-free DNA PCR can be used not only to noninvasively diagnose patients with invasive fungal disease but also to correlate the baseline cycle threshold with survival outcomes, thus potentially allowing the identification of patients at risk for poor outcomes, who may benefit from more targeted therapies.

  View details for DOI 10.1128/jcm.00394-24

  View details for PubMedID 38602412

• Neuroinvasive Francisella tularensis Infection: Report of 2 Cases and Review of the Literature. Clinical infectious diseases : an official publication of the Infectious Diseases Society of America Cash-Goldwasser, S., Beeson, A., Marzec, N., Ho, D. Y., Hogan, C. A., Budvytiene, I., Banaei, N., Born, D. E., Gephart, M. H., Patel, J., Dietrich, E. A., Nelson, C. A. 2024; 78 (Supplement_1): S55-S63

  Abstract

  Neuroinvasive infection with Francisella tularensis, the causative agent of tularemia, is rare. Establishing clinical suspicion is challenging if risk factors or clinical features classically associated with tularemia are absent. Tularemia is treatable with antibiotics; however, there are limited data to inform management of potentially fatal neuroinvasive infection.We collected epidemiologic and clinical data on 2 recent US cases of neuroinvasive F. tularensis infection, and performed a literature review of cases of neuroinvasive F. tularensis infection published after 1950.One patient presented with focal neurologic deficits and brain lesions; broad-range molecular testing on resected brain tissue detected F. tularensis. The other patient presented with meningeal signs; tularemia was suspected based on animal exposure, and F. tularensis grew in cerebrospinal fluid (CSF) culture. Both patients received combination antibiotic therapy and recovered from infection. Among 16 published cases, tularemia was clinically suspected in 4 cases. CSF often displayed lymphocytic pleocytosis. Among cases with available data, CSF culture was positive in 13 of 16 cases, and F. tularensis antibodies were detected in 11 of 11 cases. Treatment typically included an aminoglycoside combined with either a tetracycline or a fluoroquinolone. Outcomes were generally favorable.Clinicians should consider neuroinvasive F. tularensis infection in patients with meningitis and signs suggestive of tularemia or compatible exposures, lymphocyte-predominant CSF, unrevealing standard microbiologic workup, or lack of response to empiric bacterial meningitis treatment. Molecular testing, culture, and serologic testing can reveal the diagnosis. Favorable outcomes can be achieved with directed antibiotic treatment.

  View details for DOI 10.1093/cid/ciad719

  View details for PubMedID 38294117

• Case Report: Relapsing Leptospirosis in an Immunocompromised Host. The American journal of tropical medicine and hygiene Prasad, R., Narsana, N. K., Ajayi, A. A., Wang, H., Patel, J., Ho, D. Y., Banaei, N., Blackburn, B. G. 2023

  Abstract

  Leptospirosis is typically a self-limited febrile illness; when it occurs, meningitis usually develops early in the course. Here, we describe a patient who had engaged in freshwater activities in Kauai that was immunocompromised due to a history of mantle cell lymphoma, autologous hematopoietic cell transplant, and hypogammaglobulinemia. He developed leptospiral meningoencephalitis 11 weeks after illness onset and persistently detectable Leptospira DNA in blood and cerebrospinal fluid along with ongoing clinical illness, despite appropriate treatment.

  View details for DOI 10.4269/ajtmh.23-0111

  View details for PubMedID 37604468

• Case Commentary: "Salvage Treatment of Refractory HSV Oral Lesions with Pritelivir in Allogeneic Hematopoietic Cell Transplant Recipients" by Bosetti et al. Antimicrobial agents and chemotherapy Srinivasan, K., Ho, D. Y. 2023: e0027623

  View details for DOI 10.1128/aac.00276-23

  View details for PubMedID 37014226

• Erythema Gyratum Repens Secondary to Pulmonary Tuberculosis. Annals of internal medicine Contag, C. A., Maloney, N., Tayyar, R., Aleshin, M. A., Novoa, R. A., Ho, D. Y. 2023

  View details for DOI 10.7326/L22-0453

  View details for PubMedID 36913686

• Herpes Simplex Virus and Varicella Zoster Virus Infections in Cancer Patients. Viruses Tayyar, R., Ho, D. 2023; 15 (2)

  Abstract

  Herpes simplex virus (HSV) and varicella zoster virus (VZV) are alpha herpesviruses that establish life-long latent infection in neuronal ganglia after primary infection. Periodic reactivation of these viruses results in recurrent infections that can have significant impact on patients' quality of life. HSV commonly causes oral and genital mucocutaneous infections whereas VZV is responsible for varicella/chickenpox and herpes zoster/shingles, but cancer patients are at particularly higher risk of complications including disseminated and visceral infections due to impaired cell-mediated immunity. While diagnosis of more common HSV and/or VZV infections is frequently clinically based, immunocompromised hosts may have atypical skin presentation or visceral involvement. Thus, diagnostic confirmation using virus-specific tests such as polymerase chain reaction or immunohistochemical staining is crucial in some cases. Oral acyclovir, valacyclovir and famciclovir are usually used for mild to moderate infections and intravenous acyclovir is the drug of choice for severe or disseminated infections. Foscarnet can be used when acyclovir-resistance is confirmed or suspected. Pharmaceutical prophylaxis against HSV and/or VZV should be considered in high-risk cancers patients. Currently, there is no commercially available vaccine against HSV, but VZV vaccines are available to prevent varicella and zoster.

  View details for DOI 10.3390/v15020439

  View details for PubMedID 36851652

  View details for PubMedCentralID PMC9961783

• Human cytomegalovirus: a survey of end-organ diseases and diagnostic challenges in solid organ transplant recipients. Current opinion in organ transplantation Contreras, G., Ho, D. 2022; 27 (4): 243-249

  Abstract

  PURPOSE OF REVIEW: Human cytomegalovirus (CMV) infection is one of the most important infectious complications in solid organ transplant (SOT) recipients, leading to significant morbidity and mortality. Therefore, early detection and prompt treatment are imperative to improve transplant outcomes. This article highlights the clinical characteristics of the most common CMV end-organ diseases in SOT recipients and their diagnostic modalities and challenges.RECENT FINDINGS: CMV can cause a variety of end-organ diseases in SOT recipients. Although CMV nucleic acid amplification by polymerase chain reaction (PCR) is frequently employed to detect CMV reactivation or infection, its predictive value for various CMV end-organ diseases remains uncertain. Given the limitation of PCR or other noninvasive tests, confirmation of CMV end-organ disease may require tissue biopsy, which may not be feasible or available, or may cause untoward complications.SUMMARY: The utility of PCR to diagnose CMV end-organ disease is limited. As CMV can infect any organ system(s), clinicians caring for SOT recipients need to maintain vigilance for any signs and symptoms of end-organ disease to allow early recognition and prompt treatment. Invasive procedures might be needed to confirm the diagnosis and minimize the empirical use of antiviral therapy that may have substantial drug toxicities.

  View details for DOI 10.1097/MOT.0000000000000992

  View details for PubMedID 36354249

• Answer to April 2022 Photo Quiz. Journal of clinical microbiology Wang, H., Zhang, J., Kao, C., Budvytiene, I., Ho, D. Y., Mathison, B., Hogan, C. A. 2022; 60 (4): e0124721

  View details for DOI 10.1128/jcm.01247-21

  View details for PubMedID 35442073

• Photo Quiz: A 25-Year-Old Man with Hematuria and a Bladder Nodule. Journal of clinical microbiology Wang, H., Zhang, J., Kao, C., Budvytiene, I., Ho, D. Y., Mathison, B., Hogan, C. A. 2022; 60 (4): e0124621

  View details for DOI 10.1128/jcm.01246-21

  View details for PubMedID 35442076

• Epidemiology of invasive fungal diseases in adults with newly diagnosed acute myeloid leukemia. Leukemia & lymphoma Miranti, E., Ho, D. Y., Enriquez, K., Subramanian, A. K., Medeiros, B. C., Epstein, D. J. 2022: 1-7

  Abstract

  Invasive fungal diseases (IFDs) are common in patients with acute myeloid leukemia (AML), but no recent data on incidence without antifungal prophylaxis are available. We evaluated the incidence of IFDs in patients with AML undergoing induction chemotherapy at Stanford University Hospital from 2012 to 2017, for up to 12weeks after induction. We also analyzed factors associated with IFD development. Thirty-six of 240 patients (13%) developed at least one proven or probable IFD. Seventy-eight percent of the proven or probable IFDs were due to Candida or Aspergillus species. Infection due to Fusarium and Mucorales was uncommon. Absolute neutrophil count (ANC) of <500L/L at the start of induction was associated with an increased risk of IFD. One hundred and eighty-seven patients (78%) were started on systemic antifungal drugs, even without microbiologic evidence of an IFD. IFDs remain frequent in AML patients undergoing induction chemotherapy without antifungal prophylaxis.

  View details for DOI 10.1080/10428194.2022.2060504

  View details for PubMedID 35410569

• Skull base osteomyelitis in patients with head and neck cancer: Diagnosis, management, and outcomes in a case series of 23 patients. Laryngoscope investigative otolaryngology Czech, M. M., Hwang, P. H., Colevas, A. D., Fischbein, N., Ho, D. Y. 2022; 7 (1): 47-59

  Abstract

  Skull base osteomyelitis (SBO) is an infection of the central cranial bones, most commonly resulting from contiguous spread of infection from adjacent head and neck structures. SBO is a well-recognized complication of treatment of head and neck cancer (HNC) that results in significant morbidity.We conducted a retrospective chart review of HNC patients diagnosed with SBO.SBO was commonly diagnosed with nasal endoscopy showing mucosal breakdown between the naso/oropharynx and skull base and with characteristic changes on CT/MRI. Culture data were often polymicrobial, inclusive of naso/oropharyngeal flora, but half of the patients additionally had antibiotic-resistant or atypical pathogens. The mean duration of antimicrobial therapy was 117 +/- 94 days. Recurrent SBO was found in half of the patients, associated with Pseudomonas aeruginosa and with persistent defects in the mucosa abutting the skull base.Diagnosis and management of SBO in HNC patients are challenging. Recommendations to aid in clinical care are proposed.4, case series.

  View details for DOI 10.1002/lio2.719

  View details for PubMedID 35155783

  View details for PubMedCentralID PMC8823154

• Invasive mold infection of the gastrointestinal tract - A case series of 22 immunocompromised patients from a single academic center. Medical mycology Quintero, O., Allard, L., Ho, D. 1800

  Abstract

  Invasive mold infection (IMI) of the gastrointestinal (GI) tract is a rare complication in immunocompromised patients that carries a high mortality rate. It is most often described in the setting of disseminated disease. Early diagnosis and treatment are critical in its management, but this is rarely obtained, leading to delayed therapy. To describe the clinical characteristics, treatment and outcomes of this infection, we reviewed all the cases of adult patients with histopathological findings from autopsy or surgical specimens that demonstrated fungal invasion into the GI tract at Stanford Hospital & Clinics from January 1997 to August 2020. Twenty-two patients that met criteria were identified and they were all immunocompromised, either due to their underlying medical conditions or the treatments that they received. The most common underlying disease was hematological malignancies (63.6%) and the most common symptoms were abdominal pain, GI bleeding and diarrhea. A majority of patients (72.7%) had disseminated invasive mold infection, while the rest had isolated GI tract involvement. In 2/3 of our cases the fungal genus or species was confirmed based on culture or PCR results. Given the very high mortality associated with GI mold infection, this diagnosis should be considered when evaluating immunocompromised patients with concerning GI signs and symptoms. A timely recognition of the infection, prompt initiation of appropriate antifungal therapy as well as surgical intervention if feasible, are key to improve survival from this devastating infection.

  View details for DOI 10.1093/mmy/myac007

  View details for PubMedID 35092429

• Skull base osteomyelitis in patients with head and neck cancer: Diagnosis, management, and outcomes in a case series of 23 patients LARYNGOSCOPE INVESTIGATIVE OTOLARYNGOLOGY Czech, M. M., Hwang, P. H., Colevas, A., Fischbein, N., Ho, D. Y. 2022

  View details for DOI 10.1002/lio2.719

  View details for Web of Science ID 000738559200001

• Hemophagocytic lymphohistiocytosis secondary to progressive disseminated histoplasmosis presenting as cellulitis. Medical mycology case reports Puing, A. G., Raghavan, S. S., Aleshin, M. A., Ho, D. Y. 2021; 33: 18-20

  Abstract

  Histoplasmosis-associated hemophagocytic lymphohistiocytosis is a rate but lethal disease in immunocompromised hosts. Unusual clinical presentations make diagnosing invasive fungal infection even more challenging. Here we present a case of hemophagocytic lymphohistiocytosis secondary to progressive disseminated histoplasmosis presenting as cellulitis in a patient with systemic lupus erythematous. A high index of suspicion combined with histopathology and molecular diagnostic techniques are important to establish an accurate and timely diagnosis of opportunistic infections in immunocompromised patients.

  View details for DOI 10.1016/j.mmcr.2021.06.002

  View details for PubMedID 34307009

• Cutaneous cytomegalovirus - A case of disseminated cytomegalovirus presenting with extensive ulcerative skin lesions in a renal transplant recipient. Transplant infectious disease : an official journal of the Transplantation Society Ferguson, J., Mooney, K., Saleem, A., Stevens, B. A., Pinsky, B. A., Centkowski, S., Zaba, L. C., Ho, D. Y. 2021

  Abstract

  Cytomegalovirus (CMV) reactivation is common in organ transplant recipients and can lead to significant morbidity and mortality. Cutaneous CMV findings are rarely reported in the literature and diagnosis can be delayed if not clinically recognized. We describe a case of a female patient 20 years post renal transplant who presented with extensive ulcerative skin lesions and diarrhea. She rapidly deteriorated and died on day 5 of hospitalization. Autopsy noted extensive CMV involvement of skin and gastrointestinal (GI) tract by CMV-specific immunohistochemistry.

  View details for DOI 10.1111/tid.13582

  View details for PubMedID 33533137

• Clinical Accuracy and Impact of Plasma Cell-Free DNA Fungal PCR Panel for Non-Invasive Diagnosis of Fungal Infection. Clinical infectious diseases : an official publication of the Infectious Diseases Society of America Senchyna, F. n., Hogan, C. A., Murugesan, K. n., Moreno, A. n., Ho, D. Y., Subramanian, A. n., Schwenk, H. T., Budvytiene, I. n., Costa, H. A., Gombar, S. n., Banaei, N. n. 2021

  Abstract

  Invasive fungal infection (IFI) is a growing cause of morbidity and mortality in oncology and transplant patients. Diagnosis of IFI is often delayed due to need for invasive biopsy and low sensitivity of conventional diagnostic methods. Fungal cell-free DNA (cfDNA) detection in plasma is a novel testing modality for the non-invasive diagnosis of IFI.A novel bioinformatic pipeline was created to interrogate fungal genomes and identify multicopy sequences for cfDNA PCR targeting. A real-time PCR panel was developed for 12 genera and species most commonly causing IFI. Sensitivity and specificity of the fungal PCR panel were determined using plasma samples from patients with IFI and non-IFI controls. Clinical impact of fungal PCR panel was evaluated prospectively based on the treating team's interpretation of the results.Overall, the sensitivity and specificity were 56.5% (65/115, 95% confidence interval [CI], 47.4%-65.2%) and 99.5% (2064/2075; 95% CI, 99.0%-99.7%), respectively. In the subset of patients with an optimized plasma volume (2mL), sensitivity was 69.6% (48/69; 95% CI, 57.9%-79.2%). Sensitivity was 91.7% (11/12; 95% CI, 62.5%-100%) for detection of Mucorales agents, 56.3% (9/16; 95% CI, 33.2%-76.9%) for Aspergillus species, and 84.6% (11/13; 95% CI, 56.5%-96.9%) for Candida albicans. In a prospective evaluation of 226 patients with suspected IFI, cfDNA testing was positive in 47 (20.8%) patients and resulted in a positive impact on clinical management in 20/47 (42.6%).The fungal cfDNA PCR panel offers a non-invasive approach to early diagnosis of IFI, providing actionable results for personalized care.

  View details for DOI 10.1093/cid/ciab158

  View details for PubMedID 33606010

• Epstein-Barr virus-positive lymphoproliferative disorder manifesting as pulmonary disease in a patient with acute myeloid leukemia: a case report. Journal of medical case reports Dutta, R. n., Miao, S. Y., Phan, P. n., Fernandez-Pol, S. n., Shiraz, P. n., Ho, D. n., Mannis, G. N., Zhang, T. Y. 2021; 15 (1): 170

  Abstract

   Patients with lymphoproliferative disorders following hematopoietic stem cell transplant (HSCT) most commonly present with fever and lymphadenopathy within the first 5 months of transplant. Pulmonary post-transplant lymphoproliferative disorder (PTLD) is a particularly aggressive and rapidly progressive disease, with high morbidity and mortality. There are a very limited number of reported pulmonary PTLD cases following HSCT in patients with acute myeloid leukemia (AML). Early diagnosis and detection of pulmonary PTLD is critical given its high lethality. However, variable clinical presentations and nonspecific radiographic findings make pulmonary PTLD difficult to distinguish from other more common causes of pulmonary disease in AML patients.Here, we describe a 68-year-old Caucasian man who presented for salvage induction therapy following relapse of his AML after a haploidentical allogeneic HSCT 10 months earlier. He developed recurrent fevers, dry cough, and hypoxemia, with chest computed tomography (CT) showing bibasilar consolidations and increased nodularity without increased lymphadenopathy. His symptoms initially improved with antibiotic and antifungal therapy, but his follow-up chest CT showed progression of disease despite symptomatic improvement. Epstein-Barr virus (EBV) was detected in his blood by polymerase chain reaction (PCR), and a lung biopsy revealed monomorphic PTLD with B cells positive for EBV. Unfortunately, the patient's condition rapidly deteriorated, and he passed away prior to treatment initiation. To our knowledge, this is the first reported case of an AML patient developing pulmonary PTLD relatively late in his post-transplant course in the setting of relapsed disease and salvage therapy. Pulmonary PTLD, a rare but highly lethal disorder, can imitate the symptoms and radiographic findings of pneumonia, a common diagnosis in immunocompromised AML patients. This case illustrates the importance of considering pulmonary PTLD in the differential diagnosis for pulmonary disease in AML patients with a history of HSCT, especially in the setting of progressive radiographic findings despite broad antibacterial and antifungal therapy. Further, our case demonstrates the importance of biopsy and uninterrupted EBV DNA monitoring in the definitive diagnosis of PTLD, given nonspecific symptomatology and radiographic findings.

  View details for DOI 10.1186/s13256-021-02744-2

  View details for PubMedID 33773605

• Opportunistic Invasive Fungal Infections Mimicking Progression of Non-Small-Cell Lung Cancer. Clinical lung cancer Park, M., Ho, D. Y., Wakelee, H. A., Neal, J. W. 2020

  Abstract

  BACKGROUND: Many studies have shown that invasive pulmonary aspergillosis, cryptococcosis, and mucormycosis can mimic radiographic and clinical features of primary lung cancer. However, more research surveying the incidence and outcomes of these fungal infections among patients with a history of lung cancer is needed. The aim of this study was to describe the occurrence and clinical outcomes of opportunistic invasive fungal infections that can mimic tumors in non-small-cell lung cancer patients.PATIENTS AND METHODS: Patients seen at Stanford University Medical Center from January 1, 2007, to May 1, 2020, with pulmonary aspergillosis, cryptococcosis, or mucormycosis after non-small-cell lung cancer (NSCLC) diagnosis were reviewed. The European Organization for Research and Treatment of Cancer National Institute of Allergy and Infectious Diseases Mycoses Study Group criteria was used to classify patients with evidence of proven or probable invasive fungal infection within our cohort.RESULTS: A total of 12 patients with proven or probable invasive mold infection (including 8 cases of aspergillosis) and 1 patient with proven cryptococcosis were identified, without any cases of mucormycosis. Of this cohort, 6 patients (46%) showed radiographic findings that were found to be most consistent with lung cancer by radiologists. Eight cases (62%) were suspected of cancer recurrence or progression by the treatment team on the basis of additional considerations of medical history and clinical symptoms. Most patients had active NSCLC or had a history of recurrence without active NSCLC at the time of fungal discovery (11 patients; 85%). Most patients died without full recovery (7 patients; 54%).CONCLUSIONS: Invasive pulmonary aspergillosis and cryptococcosis can often be mistaken as cancer recurrence or progression in patients with a history of NSCLC because of mimicking radiographic and clinical characteristics.

  View details for DOI 10.1016/j.cllc.2020.10.001

  View details for PubMedID 33168426

• Atypical Blastomycosis Masquerading as Lofgren Syndrome. American journal of respiratory and critical care medicine Shaller, B. D., Chen, S. B., Ho, D. Y., Yu, D. H. 2020

  View details for DOI 10.1164/rccm.201911-2158IM

  View details for PubMedID 32516540

• Influence of Immunosuppression on Seroconversion Against SARS-Cov-2 in Two Kidney Transplant Recipients. Transplant infectious disease : an official journal of the Transplantation Society Wang, A. X., Quintero Cardona, O. n., Ho, D. Y., Busque, S. n., Lenihan, C. R. 2020: e13423

  Abstract

  Solid organ transplant recipients are at risk for infectious complications due to chronic immunosuppression. The outbreak of Coronavirus Disease 2019 (COVID-19) in United States has raised growing concerns for the transplant patient population. We seek to add to the current limited literature on COVID-19 in transplant recipients by describing the clinical course of two kidney transplant recipients with SARS-Cov-2 infection monitored by both RT-PCR and serology. Through careful adjustment of their immunosuppression regimen, both patients had excellent recovery with intact graft function and development of anti-SARS-Cov-2 antibodies.

  View details for DOI 10.1111/tid.13423

  View details for PubMedID 32701196

• Herpesvirus Infections Potentiated by Biologics. Infectious disease clinics of North America Ho, D. Y., Enriquez, K. n., Multani, A. n. 2020; 34 (2): 311–39

  Abstract

  Herpesviruses such as herpes simplex virus (HSV) type 1 and 2, varicella-zoster virus (VZV), and cytomegalovirus (CMV) maintain lifelong latency in the host after primary infection and can reactivate periodically either as asymptomatic viral shedding or as clinical disease. Immunosuppression, including biologic therapy, may increase frequency and severity of herpesvirus reactivation and infection. Licensed biologics are reviewed regarding their risks of potentiating HSV, VZV, and CMV reactivation and infection. Approaches to prophylaxis against HSV, VZV, and CMV infection or reactivation are discussed.

  View details for DOI 10.1016/j.idc.2020.02.006

  View details for PubMedID 32444012

• JC Polyomavirus Infection Potentiated by Biologics. Infectious disease clinics of North America Multani, A. n., Ho, D. Y. 2020; 34 (2): 359–88

  Abstract

  The risk of JC polyomavirus encephalopathy varies among biologic classes and among agents within the same class. Of currently used biologics, the highest risk is seen with natalizumab followed by rituximab. Multiple other agents have also been implicated. Drug-specific causality is difficult to establish because many patients receive multiple immunomodulatory medications concomitantly or sequentially, and have other immunocompromising factors related to their underlying disease. As use of biologic therapies continues to expand, further research is needed into pathogenesis, treatment, and prevention of JC polyomavirus encephalopathy such that risk for its development is better understood and mitigated, if not eliminated altogether.

  View details for DOI 10.1016/j.idc.2020.02.007

  View details for PubMedID 32444013

• Infections Related to Biologics. Infectious disease clinics of North America Ho, D. Y., Subramanian, A. K. 2020; 34 (2): xiii-xvi

  View details for DOI 10.1016/j.idc.2020.04.001

  View details for PubMedID 32444015

• Simultaneous Coccidioidomycosis and Phaeohyphomycosis in a Kidney Transplant Recipient: A Case Report and Literature Review. Transplant infectious disease : an official journal of the Transplantation Society Puing, A. G., Couture-Cossette, A. n., Wang, A. X., Zygourakis, C. C., Cheng, X. n., Stevens, B. A., Banaei, N. n., Novoa, R. A., Ho, D. Y., Subramanian, A. n. 2020: e13365

  Abstract

  Advances in solid organ transplantation have improved the survival of end-stage organ disease at the expense of an increased risk for opportunistic infections. Unusual clinical presentations and the possibility of concurrent infections make diagnosing invasive fungal infection (IFI) more difficult. Here we present a case of simultaneous vertebral infection caused by Coccidioides immitis-posadasii and subcutaneous phaeohyphomycosis due to Nigrograna mackinnonii in a kidney transplant recipient. The diagnosis of both infections required invasive procedures to obtain tissue and a high index of suspicion that more than one IFI could be present. A multidisciplinary team approach for the management of immunocompromised patients with suspected or diagnosed IFI is warranted.

  View details for DOI 10.1111/tid.13365

  View details for PubMedID 32533741

• Missed diagnosis and misdiagnosis of infectious diseases in hematopoietic cell transplant recipients: an autopsy study. Blood advances Multani, A. n., Allard, L. S., Wangjam, T. n., Sica, R. A., Epstein, D. J., Rezvani, A. R., Ho, D. Y. 2019; 3 (22): 3602–12

  Abstract

  Hematopoietic cell transplantation (HCT) is potentially curative for patients with hematologic disorders, but carries significant risks of infection-related morbidity and mortality. Infectious diseases are the second most common cause of death in HCT recipients, surpassed only by progression of underlying disease. Many infectious diseases are difficult to diagnose and treat, and may only be first identified by autopsy. However, autopsy rates are decreasing despite their value. The clinical and autopsy records of adult HCT recipients at our center who underwent autopsy between 1 January 2000 and 31 December 2017 were reviewed. Discrepancies between premortem clinical diagnoses and postmortem autopsy diagnoses were evaluated. Of 185 patients who underwent autopsy, 35 patients (18.8%) had a total of 41 missed infections. Five patients (2.7%) had >1 missed infection. Of the 41 missed infections, 18 (43.9%) were viral, 16 (39.0%) were fungal, 5 (12.2%) were bacterial, and 2 (4.9%) were parasitic. According to the Goldman criteria, 31 discrepancies (75.6%) were class I, 5 (12.2%) were class II, 1 (2.4%) was class III, and 4 (9.8%) were class IV. Autopsies of HCT recipients frequently identify clinically significant infectious diseases that were not suspected premortem. Had these infections been suspected, a change in management might have improved patient survival in many of these cases. Autopsy is underutilized and should be performed regularly to help improve infection-related morbidity and mortality. Illustrative cases are presented and the lessons learned from them are also discussed.

  View details for DOI 10.1182/bloodadvances.2019000634

  View details for PubMedID 31743391

• Scedosporium apiospermum infection of the urinary system with a review of treatment options and cases in the literature TRANSPLANT INFECTIOUS DISEASE Benamu, E., Yu, A., Xie, L., Fernandez-Pol, S., Liu, A. Y., Ho, D. Y. 2018; 20 (1)

  Abstract

  Infection with Scedosporium species is associated with a significant morbidity and mortality and is becoming increasingly common, especially in immunocompromised patients. We describe the presentation and successful management of an immunocompromised patient with Scedosporium apiospermum infection of the upper urinary tract system, a rare disease manifestation. The current literature on urinary tract scedosporiosis is further reviewed with emphasis on treatment options and limitations of current antifungal therapy.

  View details for PubMedID 29111602

  View details for PubMedCentralID PMC5871223

• Fatal Emmonsia sp Infection and Fungemia after Orthotopic Liver Transplantation EMERGING INFECTIOUS DISEASES Kappagoda, S., Adams, J. Y., Luo, R., Banaei, N., Concepcion, W., Ho, D. Y. 2017; 23 (2): 346–49

  Abstract

  We report a fatal case of disseminated Emmonsia sp. infection in a 55-year-old man who received an orthotopic liver transplant. The patient had pneumonia and fungemia, and multisystem organ failure developed. As human habitats and the number of immunocompromised patients increase, physicians must be aware of this emerging fungal infection.

  View details for DOI 10.3201/eid2302.160799

  View details for Web of Science ID 000393088600032

  View details for PubMedID 28098544

  View details for PubMedCentralID PMC5324819

• Donor-Derived Coccidioides immitis Endocarditis and Disseminated Infection in the Setting of Solid Organ Transplantation. Open forum infectious diseases Nelson, J. K., Giraldeau, G., Montoya, J. G., Deresinski, S., Ho, D. Y., Pham, M. 2016; 3 (3): ofw086-?

  Abstract

  Background.  Endocarditis is a rare manifestation of infection with Coccidioides. This is the first reported case of donor-derived Coccidioides endocarditis obtained from a heart transplant. Methods.  We present a unique case of donor-derived Coccidioides immitis endocarditis and disseminated infection in a heart transplant patient. We also conducted a review of the literature to identify other cases of donor-derived coccidioidomycosis in solid organ transplant recipients and reviewed their clinical characteristics. Results.  Fifteen prior cases of donor-derived coccidioidomycosis were identified. A majority of these cases were diagnosed by positive culture (83%). Mortality was high at 58%. Conclusions.  Clinicians should maintain a high index of suspicion for disseminated coccidioidomycosis in patients who received transplants with organs from donors with a history of residing in endemic regions.

  View details for DOI 10.1093/ofid/ofw086

  View details for PubMedID 27413765

• Tolerability of Fluoroquinolones in Management of Latent Tuberculosis in Liver Transplant Candidates CLINICAL INFECTIOUS DISEASES Tien, V., Robilotti, E., Callister, D., Subramanian, A., Lutchman, G., Ho, D. Y. 2015; 61 (10): 1631–U154

  View details for PubMedID 26224000

• Randomized, placebo-controlled trial to assess the safety and immunogenicity of an adenovirus type 35-based circumsporozoite malaria vaccine in healthy adults. Human vaccines & immunotherapeutics Creech, C. B., Dekker, C. L., Ho, D., Phillips, S., Mackey, S., Murray-Krezan, C., Grazia Pau, M., Hendriks, J., Brown, V., Dally, L. G., Versteege, I., Edwards, K. M. 2013; 9 (12): 2548-2557

  Abstract

  Malaria results in over 650 000 deaths each year; thus, there is an urgent need for an effective vaccine. Pre-clinical studies and recently reported human trials suggest that pre-erythrocytic stage vaccines can provide protection against infection. A Phase 1, randomized, placebo-controlled, dose-escalation study was conducted with a vaccine composed of a replication-deficient adenovirus-35 backbone with P. falciparum circumsporozoite (CS) surface antigen (Ad35.CS.01). Healthy adult subjects received three doses of 10 (8), 10 (9), 10 (10), or 10 (11) vp/mL Ad35.CS.01 vaccine or saline placebo intramuscularly at 0, 1, and 6-mo intervals. Adverse events were assessed and anti-CS antibody responses were determined by ELISA. Seventy-two individuals were enrolled, with age, gender, and ethnicity similar across each study arm. While the vaccine was generally well tolerated, adverse events were more frequent in the highest dose groups (10 (10) and 10 (11) vp/mL). More robust humoral responses were also noted at the highest doses, with 73% developing a positive ELISA response after the three dose series of 10 (11) vp/mL. The Ad35.CS.01 vaccine was most immunogenic at the highest dosages (10 (10) and 10 (11) vp/mL). Reactogenicity findings were more common after the 10 (11) vp/mL dose, although most were mild or moderate in nature and resolved without therapy.

  View details for DOI 10.4161/hv.26038

  View details for PubMedID 23955431

• Randomized, placebo-controlled trial to assess the safety and immunogenicity of an adenovirus type 35-based circumsporozoite malaria vaccine in healthy adults HUMAN VACCINES & IMMUNOTHERAPEUTICS Creech, C. B., Dekker, C. L., Ho, D., Phillips, S., Mackey, S., Murray-Krezan, C., Pau, M. G., Hendriks, J., Brown, V., Dally, L. G., Versteege, I., Edwards, K. M. 2013; 9 (12): 2548-2557

  Abstract

  Malaria results in over 650 000 deaths each year; thus, there is an urgent need for an effective vaccine. Pre-clinical studies and recently reported human trials suggest that pre-erythrocytic stage vaccines can provide protection against infection. A Phase 1, randomized, placebo-controlled, dose-escalation study was conducted with a vaccine composed of a replication-deficient adenovirus-35 backbone with P. falciparum circumsporozoite (CS) surface antigen (Ad35.CS.01). Healthy adult subjects received three doses of 10 (8), 10 (9), 10 (10), or 10 (11) vp/mL Ad35.CS.01 vaccine or saline placebo intramuscularly at 0, 1, and 6-mo intervals. Adverse events were assessed and anti-CS antibody responses were determined by ELISA. Seventy-two individuals were enrolled, with age, gender, and ethnicity similar across each study arm. While the vaccine was generally well tolerated, adverse events were more frequent in the highest dose groups (10 (10) and 10 (11) vp/mL). More robust humoral responses were also noted at the highest doses, with 73% developing a positive ELISA response after the three dose series of 10 (11) vp/mL. The Ad35.CS.01 vaccine was most immunogenic at the highest dosages (10 (10) and 10 (11) vp/mL). Reactogenicity findings were more common after the 10 (11) vp/mL dose, although most were mild or moderate in nature and resolved without therapy.

  View details for DOI 10.4161/hv.26038

  View details for Web of Science ID 000330383200015

• Utility of DNA Sequencing for Direct Identification of Invasive Fungi From Fresh and Formalin-Fixed Specimens AMERICAN JOURNAL OF CLINICAL PATHOLOGY Moncada, P. A., Budvytiene, I., Ho, D. Y., Deresinski, S. C., Montoya, J. G., Banaei, N. 2013; 140 (2): 203-208

  Abstract

  Objectives: To describe and discuss the utility and potential pitfalls of ribosomal RNA locus sequencing for direct identification of invasive fungi from fresh and formalin-fixed, paraffin-embedded specimens. Methods: DNA was extracted from fresh and formalin-fixed, paraffin-embedded tissue and subjected to real-time polymerase chain reaction (PCR) targeting ITS2 and D2 regions of fungal ribosomal RNA locus. Cycle sequencing was performed on PCR products, and the identity of sequences was determined using a public database. Results: Four clinical cases of invasive fungal infection are presented to illustrate the utility of DNA sequencing for determining etiology when microbiological culture is negative, for shortening the time to identification of slow-growing fungi, for guiding antifungal therapy, and for shedding light on the pathogenesis of disseminated fungal infection. Conclusions: Fungal ribosomal RNA locus sequencing from fresh or formalin-fixed, paraffin-embedded specimens is a powerful tool for rapid and accurate diagnosis of patients with culture-negative or uncultured invasive mycosis.

  View details for DOI 10.1309/AJCPNSU2SDZD9WPW

  View details for PubMedID 23897255

• Utility of DNA Sequencing for Direct Identification of Invasive Fungi From Fresh and Formalin-Fixed Specimens AMERICAN JOURNAL OF CLINICAL PATHOLOGY Moncada, P. A., Budvytiene, I., Ho, D. Y., Deresinski, S. C., Montoya, J. G., Banaei, N. 2013; 140 (2): 203-208

  View details for DOI 10.1309/AJCPNSU2SDZD9WPW

  View details for Web of Science ID 000919509000009

• Clinical Significance of Low Cytomegalovirus DNA Levels in Human Plasma JOURNAL OF CLINICAL MICROBIOLOGY Waggoner, J., Ho, D. Y., Libiran, P., Pinsky, B. A. 2012; 50 (7): 2378-2383

  Abstract

  The clinical significance of the detection of low copy numbers of cytomegalovirus (CMV) DNA in immune-suppressed patients remains unclear. In this study, we compared the artus CMV Rotor-Gene PCR, utilizing an automated nucleic acid extraction and assay setup (the artus CMV protocol), with the COBAS Amplicor CMV Monitor test (our reference protocol). We then analyzed the results of all CMV PCR tests ordered following the implementation of the artus CMV protocol at our institution and followed 91 adult patients with positive test results. The artus CMV protocol had a linear range extending from 2.0 to 7.0 log(10) copies/ml and had a lower limit of 95% detection of 57 copies/ml. With archived plasma samples, this protocol demonstrated 100% sensitivity and 94% specificity for the detection of CMV DNA. Following implementation of the artus CMV protocol, 320 of 1,403 (22.8%) plasma samples tested positive (compared with 323/3,579 [9.0%] samples in the preceding 6 months), and 227 (16.2%) samples had copy numbers of <400/ml. Ninety-one adult patients had at least one positive test. The data were analyzed using a threshold of 200 copies/ml, and in 22 episodes, the viral load increased from <200 copies/ml to ≥ 200 copies/ml on sequential tests. In 21 of these 22 episodes, either the viral load continued to increase or antiviral treatment was initiated in response to the repeat value. In summary, we evaluate the performance characteristics of a protocol utilizing the artus CMV PCR and identify clinically meaningful changes in CMV DNA copy numbers even when they are initially detected at a low level.

  View details for DOI 10.1128/JCM.06800-11

  View details for Web of Science ID 000307360800033

  View details for PubMedID 22518866

  View details for PubMedCentralID PMC3405616

• Early CMV Viremia Is Associated with Impaired Viral Control following Nonmyeloablative Hematopoietic Cell Transplantation with a Total Lymphoid Irradiation and Antithymocyte Globulin Preparative Regimen BIOLOGY OF BLOOD AND MARROW TRANSPLANTATION Schaenman, J. M., Shashidhar, S., Rhee, C., Wong, J., Navato, S., Wong, R. M., Ho, D. Y., Arai, S., Johnston, L., Brown, J. M. 2011; 17 (5): 693-702

  Abstract

  The reconstitution of immune function after hematopoietic cell transplant (HCT) plays an important role in the control of viral infections. Both donor and recipient cytomegalovirus (CMV) serostatus has been shown to contribute to effective immune function; however, the influence of a nonmyeloablative preparative (NMA) regimen using total lymphoid irradiation (TLI) and antithymocyte globulin (ATG) on antiviral immune reconstitution has not yet been described. In 117 recipients of NMA HCT patients following ATG and TLI, not unexpectedly, CMV viremia was seen in approximately 60% of the seropositive patients regardless of donor serostatus, and recipient seropositivity significantly increased the odds of CMV viremia after transplant in a multivariate analysis. The administration of ATG and TLI resulted in a strikingly earlier viremia in the posttransplant period when compared to the previously reported timing of viremia following myeloablative preparative regimens, especially for transplant recipients who were seropositive for CMV with seronegative donors. Furthermore, early viremia in the setting of a CMV naïve donor was associated with a delay in functional antiviral control. These observations demonstrate the dynamic nature of immunity in relation to CMV antigen exposure in the complex environment resulting from NMA conditions where both donor and residual recipient immune response affect viral control.

  View details for DOI 10.1016/j.bbmt.2010.08.010

  View details for Web of Science ID 000290061500012

  View details for PubMedID 20736077

• Brain Abscess Caused by Phaeoacremonium parasiticum in an Immunocompromised Patient JOURNAL OF CLINICAL MICROBIOLOGY McNeil, C. J., Luo, R. F., Vogel, H., Banaei, N., Ho, D. Y. 2011; 49 (3): 1171-1174

  Abstract

  Phaeoacremonium parasiticum is an environmental fungus usually associated with subcutaneous infections. We report the first documented case of central nervous system involvement with brain abscess formation in a patient with chronic granulomatous disease and review the literature on Phaeoacremonium parasiticum infections.

  View details for DOI 10.1128/JCM.00830-10

  View details for PubMedID 21191052

• Treatment of Acyclovir-Resistant Herpes Simplex Virus with Continuous Infusion of High-Dose Acyclovir in Hematopoietic Cell Transplant Patients BIOLOGY OF BLOOD AND MARROW TRANSPLANTATION Kim, J. H., Schaenman, J. M., Ho, D. Y., Brown, J. M. 2011; 17 (2): 259-264

  Abstract

  Infection because of herpes simplex virus (HSV) that is resistant to acyclovir (ACV) poses treatment challenges in hematopoietic cell transplant (HCT) patients. We present a series of patients with ACV-resistant HSV following HCT who were successfully treated with continuous infusion high-dose ACV after failing standard treatment regimens for ACV-resistant HSV.

  View details for DOI 10.1016/j.bbmt.2010.06.020

  View details for Web of Science ID 000287350400010

  View details for PubMedID 20615475

• Yield of diagnostic procedures for invasive fungal infections in neutropenic febrile patients with chest computed tomography abnormalities MYCOSES Ho, D. Y., Lin, M., Schaenman, J., Rosso, F., Leung, A. N., Coutre, S. E., Sista, R. R., Montoya, J. G. 2011; 54 (1): 59-70

  Abstract

  Haematological patients with neutropenic fever are frequently evaluated with chest computed tomography (CT) to rule out invasive fungal infections (IFI). We retrospectively analysed data from 100 consecutive patients with neutropenic fever and abnormal chest CT from 1998 to 2005 to evaluate their chest CT findings and the yield of diagnostic approaches employed. For their initial CTs, 79% had nodular opacities, with 24.1% associated with the halo sign. Other common CT abnormalities included pleural effusions (48%), ground glass opacities (37%) and consolidation (31%). The CT findings led to a change in antifungal therapy in 54% of the patients. Fifty-six patients received diagnostic procedures, including 46 bronchoscopies, 25 lung biopsies and seven sinus biopsies, with a diagnostic yield for IFI of 12.8%, 35.0% and 83.3%, respectively. In conclusion, chest CT plays an important role in the evaluation of haematological patients with febrile neutropenia and often leads to a change in antimicrobial therapy. Pulmonary nodules are the most common radiological abnormality. Sinus or lung biopsies have a high-diagnostic yield for IFI as compared to bronchoscopy. Patients with IFI may not have sinus/chest symptoms, and thus, clinicians should have a low threshold for performing sinus/chest imaging, and if indicated and safe, a biopsy of the abnormal areas.

  View details for DOI 10.1111/j.1439-0507.2009.01760.x

  View details for PubMedID 19793207

• Treatment of Severe Acyclovir-Resistant Herpes Simplex Virus Infection with Continuous Infusion of High Dose Acyclovir Following Hematopoietic Cell Transplantation Kim, J. H., Schaenman, J., Ho, D. Y., Brown, J. M. AMER SOC HEMATOLOGY. 2009: 876

  View details for Web of Science ID 000272725802592

• Safety and immunogenicity of inactivated, Vero cell culture-derived whole virus influenza A/H5N1 vaccine given alone or with aluminum hydroxide adjuvant in healthy adults VACCINE Keitel, W. A., Dekker, C. L., Mink, C., Campbell, J. D., Edwards, K. M., Patel, S. M., Ho, D. Y., Talbot, H. K., Guo, K., Noah, D. L., Hill, H. 2009; 27 (47): 6642-6648

  Abstract

  Dosage-sparing strategies, adjuvants and alternative substrates for vaccine production are being explored for influenza vaccine development. We assessed the safety and immunogenicity of a Vero cell culture-grown inactivated whole virus influenza A/H5N1 vaccine with or without aluminum hydroxide adjuvant [Al(OH)(3)] in healthy young adults. Vaccines were well tolerated, but injection site discomfort was more frequent in groups receiving Al(OH)(3). Dose-related increases in serum antibody levels were observed. Neutralizing antibody titers varied significantly when tested by two different laboratories. Al(OH)(3) did not enhance HAI or neutralizing antibody responses, and contributed to increased injection site pain. Because influenza antibody titers vary significantly between different laboratories, international standardization of assays is warranted.

  View details for DOI 10.1016/j.vaccine.2009.03.015

  View details for Web of Science ID 000272056300022

  View details for PubMedID 19773098

  View details for PubMedCentralID PMC3022490

• Varicella Zoster Virus In: Yu VL, Weber R, Raoult D (eds.), Antinicrobial Therapy and Vaccines 3rd edition Ho DY, Arvin Am, Newland JG 2009
• Immunogenicity, safety and consistency of new trivalent inactivated influenza vaccine VACCINE Talbot, H. K., Keitel, W., Cate, T. R., Treanor, J., Campbell, J., Bradye, R. C., Graham, I., Dekker, C. L., Ho, D., Winokur, P., Walter, E., Bennet, J., Formica, N., Hartel, G., Skeljo, M., Edwards, K. M. 2008; 26 (32): 4057-4061

  Abstract

  To augment the available influenza vaccine supply, a phase III study was conducted to evaluate the immunogenicity, safety, and consistency of a new trivalent inactivated influenza vaccine manufactured by CSL Limited. Healthy adults (ages 18-64) were randomized to receive either a single dose of TIV from multi-dose vials with thimerosal, TIV from pre-filled syringes without thimerosal, or placebo. Of the TIV recipients, 97.8% achieved a post-vaccination titer > or =40 against H1N1, 99.9% against H3N2 component, and 94.2% against influenza B. Few local or systemic adverse events were noted after vaccination with either TIV presentation. TIV was well tolerated and immunogenic.

  View details for DOI 10.1016/j.vaccine.2008.05.024

  View details for Web of Science ID 000258610900014

  View details for PubMedID 18602726

  View details for PubMedCentralID PMC2605420

• Varicella Zoster Virus Infections In: Blume KG, Negrin RS, Foramn SJ, Appelbaum (eds.), Thomas? Hematopoietic Cell Transplantation 4th edition. Ho DY, Arvin AM 2008; Chapter 92
• Treating disseminated fusariosis: amphotericin B, voriconazole or both? MYCOSES Ho, D. Y., Lee, J. D., Rosso, F., Montoya, J. G. 2007; 50 (3): 227-231

  Abstract

  Disseminated Fusarium infection can cause significant morbidity and mortality in immunocompromised patients. We present a case of disseminated fusariosis in a patient with neutropenic fever successfully treated using both liposomal amphotericin B and voriconazole. Combination anti-fungal therapy may be considered for such patients, particularly for those failing single-drug therapy.

  View details for DOI 10.1111/j.0933-7407.2006.2006.01346.x

  View details for PubMedID 17472622

• Potassium channel gene therapy can prevent neuron death resulting from necrotic and apoptotic insults JOURNAL OF NEUROCHEMISTRY Lee, A. L., Dumas, T. C., Tarapore, P. E., Webster, B. R., Ho, D. Y., Kaufer, D., Sapolsky, R. M. 2003; 86 (5): 1079-1088

  Abstract

  Necrotic insults such as seizure are excitotoxic. Logically, membrane hyperpolarization by increasing outwardly conducting potassium channel currents should attenuate hyperexcitation and enhance neuron survival. Therefore, we overexpressed a small-conductance calcium-activated (SK2) or voltage-gated (Kv1.1) channel via viral vectors in cultured hippocampal neurons. We found that SK2 or Kv1.1 protected not only against kainate or glutamate excitotoxicity but also increased survival after sodium cyanide or staurosporine. In vivo overexpression of either channel in dentate gyrus reduced kainate-induced CA3 lesions. In hippocampal slices, the kainate-induced increase in granule cell excitability was reduced by overexpression of either channel, suggesting that these channels exert their protective effects during hyperexcitation. It is also important to understand any functional disturbances created by transgene overexpression alone. In the absence of insult, overexpression of Kv1.1, but not SK2, reduced baseline excitability in dentate gyrus granule cells. Furthermore, while no behavioral disturbances during spatial acquisition in the Morris water maze were observed with overexpression of either channel, animals overexpressing SK2, but not Kv1.1, exhibited a memory deficit post-training. This difference raises the possibility that the means by which these channel subtypes protect may differ. With further development, potassium channel vectors may be an effective pre-emptive strategy against necrotic insults.

  View details for DOI 10.1046/j.1471-4159.2003.01880.x

  View details for PubMedID 12911616

• Anaphylactoid reaction to ciprofloxacin ANNALS OF PHARMACOTHERAPY Ho, D. Y., Song, J. C., Wang, C. C. 2003; 37 (7-8): 1018-1023

  Abstract

  To report a case of anaphylactoid reaction in an HIV-negative patient associated with the administration of intravenous ciprofloxacin.A 79-year-old Armenian man developed an anaphylactoid reaction following a first-time exposure to intravenous ciprofloxacin. This reaction was characterized by severe hypotension, wheezing, tachypnea, tachycardia, and pruritus. The patient had complete recovery once ciprofloxacin treatment was terminated and supportive care was provided.Fluoroquinolones are important therapeutic agents in the management of infectious diseases and are generally safe and well tolerated. Anaphylactoid and anaphylactic reactions have been documented as adverse effects of ciprofloxacin, ofloxacin, norfloxacin, levofloxacin, and moxifloxacin. To date, >33 cases have been reported with ciprofloxacin, of which at least 10 occurred in HIV-positive patients. In Europe, 15 cases of anaphylactoid reactions to ofloxacin have been reported and, more recently, with moxifloxacin. Since anaphylactoid reactions are potentially life threatening, the administration of fluoroquinolones to patients who have experienced a prior reaction to any of these agents should be avoided, unless tolerance has been confirmed by oral challenge tests.The anaphylactoid reaction in our patient was probably induced by ciprofloxacin as validated by the Naranjo probability scale. Although anaphylactoid/anaphylactic reactions are rare adverse effects of ciprofloxacin and other fluoroquinolones, clinicians should be aware of this potentially fatal event.

  View details for DOI 10.1345/aph.1C498

  View details for Web of Science ID 000184075800014

  View details for PubMedID 12841811

• Interactions among ascorbate, dehydroascorbate and glucose transport in cultured hippocampal neurons and glia BRAIN RESEARCH Patel, M., McIntosh, L., Bliss, T., Ho, D., Sapolsky, R. 2001; 916 (1-2): 127-135

  Abstract

  There is an increasing recognition of the damaging role played by oxygen radicals in mediating necrotic neuronal injury. As such, it becomes important to understand the transport mechanisms that help maintain appropriate levels of small molecule antioxidants such as ascorbate in the brain. It has long been known that the transport of dehydroascorbate (DHA) into a variety of cell types is accomplished through the Glut-1 glucose transporter. In this paper, we characterize interactions among the transports of ascorbate, DHA and glucose in hippocampal cultures. We find: (a) sodium-dependent transport of ascorbate in mixed neuronal/glial, pure glial, and neuron-enriched hippocampal cultures; in contrast, we observed no such transport of DHA; (b) such ascorbate transport appeared to be independent of the glucose transporter, in that glucose did not compete for such transport, and overexpression of the Glut-1 glucose transporter did not alter ascorbate uptake; (c) in contrast, ascorbate, at concentrations ranging from 1 to 20 mM inhibited 2-dexogyglucose transport in mixed, glial and enriched neuronal hippocampal cultures; (d) potentially, ascorbate, by acting as an electron donor, could impair the function of molecules involve in the transport or metabolism of glucose. We observed mild inhibition of glucose transport by one unrelated electron donor (glutathione). Moreover, transport was also inhibited by an ascorbate analog which is not an electron donor. Thus, we conclude that ascorbate transport in hippocampal neurons and glia occurs independent of the glucose transporter but that, nevertheless, ascorbate, at concentrations generally thought to be supraphysiological, has the potential for disrupting glucose transport.

  View details for Web of Science ID 000171812300015

  View details for PubMedID 11597599

• Neuroprotective effects of an adenoviral vector expressing the glucose transporter: a detailed description of the mediating cellular events BRAIN RESEARCH Gupta, A., Ho, D. Y., Brooke, S., Franklin, L., Roy, M., MCLAUGHLIN, J., Fink, S. L., Sapolsky, R. M. 2001; 908 (1): 49-57

  Abstract

  Considerable knowledge exists concerning the events mediating neuron death following a necrotic insult; prompted by this, there have now been successful attempts to use gene therapy approaches to protect neurons from such necrotic injury. In many such studies, however, it is not clear what sequence of cellular events connects the overexpression of the transgene with the enhanced survival. We do so, exploring the effects of overexpressing the Glut-1 glucose transporter with an adenoviral vector in hippocampal cultures challenged with the excitotoxin kainic acid (KA). Such overexpression enhanced glucose transport, attenuated the decline in ATP concentrations, decreased the release of excitatory amino acid neurotransmitters, and decreased the total free cytosolic calcium load. Commensurate with these salutary effects, neuronal survival was enhanced with this gene therapy intervention. Thus, the neuroprotective effects of this particular gene therapy occurs within the known framework of the mechanisms of necrotic neuronal injury.

  View details for Web of Science ID 000170095100005

  View details for PubMedID 11457430

• Calbindin D28K overexpression protects striatal neurons from transient focal cerebral ischemia STROKE Yenari, M. A., Minami, M., Sun, G. H., Meier, T. J., Kunis, D. M., McLaughlin, J. R., Ho, D. Y., Sapolsky, R. M., Steinberg, G. K. 2001; 32 (4): 1028-1035

  Abstract

  Increased intracellular calcium accumulation is known to potentiate ischemic injury. Whether endogenous calcium-binding proteins can attenuate this injury has not been clearly established, and existing data are conflicting. Calbindin D28K (CaBP) is one such intracellular calcium buffer. We investigated whether CaBP overexpression is neuroprotective against transient focal cerebral ischemia.Bipromoter, replication-incompetent herpes simplex virus vectors that encoded the genes for cabp and, as a reporter gene, lacZ were used. Sprague-Dawley rats received bilateral striatal injections of viral vector 12 to 15 hours before ischemia onset. With the use of an intraluminal occluding suture, animals were subjected to 1 hour of middle cerebral artery occlusion followed by 47 hours of reperfusion. Brains were harvested and stained with X-gal (to visualize beta-galactosidase, the gene product of lacZ). The number of remaining virally transfected, X-gal-stained neurons in both the ischemic and contralateral striata were counted and expressed as the percentage of surviving neurons in the ischemic striatum relative to the contralateral nonischemic striatum.Striatal neuron survivorship among cabp-injected animals was 53.5+/-4.1% (n=10) versus 26.8+/-5.4% among those receiving lacZ (n=9) (mean+/-SEM; P<0.001).We conclude that viral vector-mediated overexpression of CaBP leads to neuroprotection in this model of central nervous system injury. This is the first demonstration that CaBP overexpression protects neurons in a focal stroke model.

  View details for Web of Science ID 000167951300038

  View details for PubMedID 11283407

• Sparing of neuronal function postseizure with gene therapy PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA MCLAUGHLIN, J., Roozendaal, B., Dumas, T., Gupta, A., Ajilore, O., Hsieh, J., Ho, D., Lawrence, M., McGaugh, J. L., Sapolsky, R. 2000; 97 (23): 12804-12809

  Abstract

  Numerous studies have demonstrated that gene therapy interventions can protect neurons from death after neurological insults. In nearly all such studies, however, "protection" consists of reduced neurotoxicity, with no demonstrated preservation of neuronal function. We used a herpes simplex virus-1 system to overexpress either the Glut-1 glucose transporter (GT) (to buffer energetics), or the apoptosis inhibitor Bcl-2. Both decreased hippocampal neuron loss to similar extents during excitotoxic insults in vitro and in vivo. However, the mediating mechanisms and consequences of the two interventions differed. GT overexpression attenuated early, energy-dependent facets of cell death, blocking oxygen radical accumulation. Bcl-2 expression, in contrast, blocked components of death downstream from the energetic and oxidative facets. Most importantly, GT- but not Bcl-2-mediated protection preserved hippocampal function as assessed spatial maze performance. Thus, gene therapeutic sparing of neurons from insult-induced death does not necessarily translate into sparing of function.

  View details for Web of Science ID 000165225800082

  View details for PubMedID 11058147

  View details for PubMedCentralID PMC18845

• Gene therapies that enhance hippocampal neuron survival after an excitotoxic insult are not equivalent in their ability to maintain synaptic transmission EXPERIMENTAL NEUROLOGY Dumas, T. C., McLaughlin, J. R., Ho, D. Y., Lawrence, M. S., Sapolsky, N. M. 2000; 166 (1): 180-189

  Abstract

  Research shows that overexpression of cytoprotective genes can spare neurons from necrotic death, but few studies have addressed the functional status of surviving neurons. Overexpression of a brain glucose transporter, Glut-1, or the anti-apoptotic protein, Bcl-2, in rats decreases the size of hippocampal lesions produced by kainic acid (KA) treatment. In animals in which KA-induced lesions are reduced to similar extents by Glut-1 or Bcl-2 overexpression, spatial learning is spared by Glut-1, but not Bcl-2. We postulated that Glut-1 and Bcl-2 act differently to protect hippocampal function and investigated the effects of vector overexpression on synaptic physiology after KA treatment. Three days after KA and vector delivery to the dentate gyrus, mossy fiber-CA3 (MF-CA3) population excitatory postsynaptic potentials (EPSPs) were recorded in vitro. In addition to producing a lesion in area CA3, KA treatment reduced baseline MF-CA3 synaptic strength, posttetanic potentiation (PTP), and long-term potentiation (LTP). A similar reduction in the KA-induced lesion was produced by overexpression of Glut-1 or Bcl-2. Glut-1, but not Bcl-2, attenuated the impairments in synaptic strength and PTP. Overexpression of Glut-1 or Bcl-2 preserved LTP after KA treatment. Results indicate greater protection of MF-CA3 synaptic transmission with overexpression of Glut-1 compared to Bcl-2 and suggest that not all neuroprotective gene therapy techniques are equivalent in their ability to spare function.

  View details for Web of Science ID 000165119800016

  View details for PubMedID 11031094

• Neuroprotective potential of a viral vector system induced by a neurological insult PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA Ozawa, C. R., Ho, J. J., Tsai, D. J., Ho, D. Y., Sapolsky, R. M. 2000; 97 (16): 9270-9275

  Abstract

  Gene transfer into neurons via viral vectors for protection against acute necrotic insults has generated considerable interest. Most studies have used constitutive vector systems, limiting the ability to control transgene expression in a dose-dependent, time-dependent, or reversible manner. We have constructed defective herpes simplex virus vectors designed to be induced by necrotic neurological insults themselves. Such vectors contain a synthetic glucocorticoid-responsive promoter, taking advantage of the almost uniquely high levels of glucocorticoids-adrenal stress steroids-secreted in response to such insults. We observed dose-responsive and steroid-specific induction by endogenous and synthetic glucocorticoids in hippocampal cultures. Induction was likely to be rapid enough to allow transgenic manipulation of relatively early steps in the cascade of necrotic neuron death. The protective potential of such a vector was tested by inclusion of a neuroprotective transgene (the Glut-1 glucose transporter). Induction of this vector by glucocorticoids decreased glutamatergic excitotoxicity in culture. Finally, both exogenous glucocorticoids and excitotoxic seizures induced reporter gene expression driven from a glucocorticoid-responsive herpes simplex virus vector in the hippocampus in vivo.

  View details for Web of Science ID 000088608000091

  View details for PubMedID 10908682

  View details for PubMedCentralID PMC16857

• Limitations in the neuroprotective potential of gene therapy with Bcl-2 BRAIN RESEARCH Phillips, R. G., Lawrence, M. S., Ho, D. Y., Sapolsky, R. M. 2000; 859 (2): 202-206

  Abstract

  Considerable attention has focused on the therapeutic transfer of genes with viral vectors into neurons for the purpose of protecting against neurological insults. A number of papers have reported that overexpression of the anti-apoptotic protein Bcl-2 can protect neurons both in vitro and in vivo against a variety of necrotic insults. An emerging literature suggests that the availability of energy tends to modulate a neuron towards dying apoptotically, rather than necrotically, in the aftermath of an insult. This suggests that an anti-apoptotic protein such as Bcl-2 should be minimally protective, at best, against purely energetic insults. In support of this idea, we report that overexpression of Bcl-2 with a herpes simplex viral vector fails to protect hippocampal neurons, either in vitro or in vivo, against the electron transport uncoupler 3-acetylpyridine (3AP). As a positive control, the same vector significantly protected against the excitotoxin kainic acid. This finding supports the view that neurotoxicity induced by 3AP is likely to have only minimal apoptotic facets. On a broader level, it suggests some limitations in the neuroprotective potential of gene therapy with Bcl-2.

  View details for Web of Science ID 000086080600003

  View details for PubMedID 10719065

• An adenoviral vector expressing the glucose transporter protects cultured striatal neurons from 3-nitropropionic acid BRAIN RESEARCH Fink, S. L., Ho, D. Y., MCLAUGHLIN, J., Sapolsky, R. M. 2000; 859 (1): 21-25

  Abstract

  Considerable interest has focused on the possibility of using gene transfer techniques to introduce protective genes into neurons around the time of necrotic insults. We have previously used herpes simplex virus amplicon vectors to overexpress the rat brain glucose transporter, Glut-1 (GT), and have shown it to protect against a variety of necrotic insults both in vitro and in vivo, as well as to buffer neurons from the steps thought to mediate necrotic injury. It is critical to show the specificity of the effects of any such transgene overexpression, in order to show that protection arises from the transgene delivered, rather than from the vector delivery system itself. As such, we tested the protective potential of GT overexpression driven, in this case, by an adenoviral vector, against a novel insult, namely exposure of primary striatal cultures to the metabolic poison, 3-nitropropionic acid (3NP). We observed that GT overexpression buffered neurons from neurotoxicity induced by 3NP.

  View details for Web of Science ID 000085998400003

  View details for PubMedID 10720611

• Delivery of herpes simplex virus amplicon-based vectors to the dentate gyrus does not alter hippocampal synaptic transmission in vivo GENE THERAPY Dumas, T. D., McLaughlin, J. R., Ho, D. Y., Meier, T. J., Sapolsky, R. M. 1999; 6 (10): 1679-1684

  Abstract

  Herpes simplex virus type-1 (HSV) amplicon vectors containing neuroprotective genes can alter cell physiology and enhance survival following various insults. However, to date, little is known about effects of viral infection itself (independent of the gene delivered) on neuronal physiology. Electrically-evoked synaptic responses are routinely recorded to measure functional alterations in the nervous system and were used here to assess the potential capability of HSV vectors to disrupt physiology of the hippocampus (a forebrain structure involved in learning that is highly susceptible to necrotic insult, making it a frequent target in gene therapy research). Population excitatory post-synaptic potentials (EPSPs) were recorded in the dentate gyrus (DG) and in area CA3 in vivo 72 h after infusion of an HSV vector expressing a reporter gene (lacZ) or vehicle into the DG. Evoked perforant path (PP-DG) or mossy fiber (MF-CA3) EPSPs slope values measured across input/output (I/O) curves were not altered by infection. Paired-pulse facilitation at either recording site was also unaffected. X-gal-positive granule cells surrounded the recording electrode (PP-DG recording) and stimulating electrode tracts (MF-CA3 recording) in animals that received vector, suggesting that we had measured function, at least in part, in infected neurons. Because of the negative electrophysiological result, we sought to deliver a gene with an HSV amplicon which would affect the measured endpoints, as a positive control. Delivery of calbindin D28kpotentiated PP-DG synaptic strength, indicating that our recording system could detect alterations due to vector expression. Thus, the data indicate that HSV vectors are benign, in regard to effects on synaptic function, and support the use of these vectors as a safe method to deliver selected genes to the central nervous system.

  View details for Web of Science ID 000082957100006

  View details for PubMedID 10516716

• Calbindin D-28K gene transfer via herpes simplex virus amplicon vector decreases hippocampal damage in vivo following neurotoxic insults JOURNAL OF NEUROCHEMISTRY Phillips, R. G., Meier, T. J., Giuli, L. C., McLaughlin, J. R., Ho, D. Y., Sapolsky, M. R. 1999; 73 (3): 1200-1205

  Abstract

  Increases in cytoplasmic Ca2+ concentration ([Ca2+]i) can lead to neuron death. Preventing a rise in [Ca2+]i by removing Ca2+ from the extracellular space or by adding Ca2+ chelators to the cytosol of target cells ameliorates the neurotoxicity associated with [Ca2+]i increases. Another potential route of decreasing the neurotoxic impact of Ca2+ is to overexpress one of the large number of constitutive calcium-binding proteins. Previous studies in this laboratory demonstrated that overexpression of the gene for the calcium-binding protein calbindin D28K, via herpes simplex virus (HSV) amplicon vector, increases the survival of hippocampal neurons in vitro following energetic or excitotoxic insults but not following application of sodium cyanide. We now report that in vivo hippocampal infection with the calbindin D28K HSV vector increases neuronal survival in the dentate gyrus after application of the antimetabolite 3-acetylpyridine and increases transsynaptic neuronal survival in area CA3 following kainic acid neurotoxicity. The protective effects of infection with the calbindin D28K vector in an intact brain may prove to be beneficial during changes in Ca2+ homeostasis caused by neurological trauma associated with aging and certain neurological diseases.

  View details for Web of Science ID 000082037000035

  View details for PubMedID 10461912

• Gene transfer therapy for cerebral ischemia 7th International Symposium on the Pharmacology of Cerebral Ischemia Yenari, M. A., Fink, S. L., Lawrence, M., Sun, G. H., MCLAUGHLIN, J., Onley, D., Ho, D. Y., Sapolsky, R. M., Steinberg, G. K. MEDPHARM GMBH SCIENTIFIC PUBL. 1999: 453–465

  View details for Web of Science ID 000082191900048

• Gene therapy with HSP72 is neuroprotective in rat models of stroke and epilepsy ANNALS OF NEUROLOGY Yenari, M. A., Fink, S. L., Sun, G. H., Chang, L. K., Patel, M. K., Kunis, D. M., Onley, D., Ho, D. Y., Sapolsky, R. M., Steinberg, G. K. 1998; 44 (4): 584-591

  Abstract

  Brain areas damaged by stroke and seizures express high levels of the 72-kd heat shock protein (HSP72). Whether HSP72 represents merely a marker of stress or plays a role in improving neuron survival in these cases has been debated. Some induced tolerance experiments have provided correlative evidence for a neuroprotective effect, and others have documented neuroprotection in the absence of HSP72 synthesis. We report that gene transfer therapy with defective herpes simplex virus vectors overexpressing hsp72 improves neuron survival against focal cerebral ischemia and systemic kainic acid administration. HSP72 overexpression improved striatal neuron survival from 62.3 to 95.4% in rats subjected to 1 hour of middle cerebral artery occlusion, and improved survival of hippocampal dentate gyrus neurons after systemic kainic acid administration, from 21.9 to 64.4%. We conclude that HSP72 may participate in processes that enhance neuron survival during transient focal cerebral ischemia and excitotoxin-induced seizures.

  View details for Web of Science ID 000076316300002

  View details for PubMedID 9778256

• Gene transfer of calbindin D-28k cDNA via herpes simplex virus amplicon vector decreases cytoplasmic calcium ion response and enhances neuronal survival following glutamatergic challenge but not following cyanide JOURNAL OF NEUROCHEMISTRY Meier, T. J., Ho, D. Y., Park, T. S., Sapolsky, R. M. 1998; 71 (3): 1013-1023

  Abstract

  Excitatory amino acid overstimulation of neurons can lead to a marked rise in cytoplasmic Ca2+ concentration ([Ca2+])i) and be followed by neuron death from hours to days later. If the rise in [Ca2+]i is prevented, either by removing Ca2+ from the extracellular environment or by placing Ca2+ chelators in the cytosol of the stimulated cells, the neurotoxicity associated with excitotoxins can be ameliorated. We have recently shown that neurons infected with a herpes simplex virus amplicon vector expressing cDNA for calbindin D28k responded to hypoglycemia with decreased [Ca2+]i and increased survival relative to controls. We now report that vector-infected neurons respond to glutamatergic insults with lower [Ca2+]i than controls and with increased survival. Infected neurons exposed to sodium cyanide did not respond with lower [Ca2+]i than controls, nor did they demonstrate increased survival postinsult. We examine these results in light of our earlier report and in the context of the potential of vectors like this for neuronal gene therapy.

  View details for Web of Science ID 000075478400013

  View details for PubMedID 9721726

• The ins and outs of on and off NATURE BIOTECHNOLOGY Sapolsky, R. M., Ho, D. Y., MCLAUGHLIN, J. 1998; 16 (6): 516-516

  View details for Web of Science ID 000073930600021

  View details for PubMedID 9624676

• Gene transfer therapy for cerebral ischemia In: Krieglstein J and Oberpichler-Schwenk H (eds.), Pharmacology of Cerebral Ischemia, Medpharm, Stuttgart Yenari MA, Fink SL, Lawrence MS, Sun GH, McLaughlin J, Onley D, Ho DY, Sapolsky RM, Steinberg G 1998: 453-459
• Increased expression of calbindin D-28k via herpes simplex virus amplicon vector decreases calcium ion mobilization and enhances neuronal survival after hypoglycemic challenge JOURNAL OF NEUROCHEMISTRY Meier, T. J., Ho, D. Y., Sapolsky, R. M. 1997; 69 (3): 1039-1047

  Abstract

  Disruption of Ca2+ homeostasis often leads to neuron death. Recently, the function of calcium-binding proteins as neuronal Ca2+ buffers has been debated. We tested whether calbindin D28k functions as an intracellular Ca2+ buffer by constructing bicistronic herpes simplex virus vectors to deliver rat calbindin cDNA to hippocampal neurons in vitro. Neurons were infected with vectors delivering calbindin or a negative control or were mock-infected. After 12 or 24 h of hypoglycemia, infected cells were made aglycemic during fura-2 calcium ratiometric imaging. In response to this challenge, neuronal overexpressing calbindin had less Ca2+ mobilized as compared with negative controls or mock-infected cells. Cells were assayed for survival after 12- or 24-h hypoglycemia or aglycemia. The calbindin vector decreased neuronal death due to hypoglycemia but not aglycemia. Here we demonstrate, in response to hypoglycemic challenge, both decreased Ca2+ mobilization and increased survival of cells infected with the calbindin vector.

  View details for Web of Science ID A1997XR46700017

  View details for PubMedID 9282926

• Herpes simplex viral vectors expressing Bcl-2 are neuroprotective when delivered after a stroke JOURNAL OF CEREBRAL BLOOD FLOW AND METABOLISM Lawrence, M. S., McLaughlin, J. R., Sun, G. H., Ho, D. Y., McIntosh, L., Kunis, D. M., Sapolsky, R. M., Steinberg, G. K. 1997; 17 (7): 740-744

  Abstract

  Considerable interest has focused on the possibility of using viral vectors to deliver genes to the central nervous system for the purpose of decreasing necrotic neuronal injury. To that end, we have previously shown that a herpes simplex virus (HSV) vector expressing Bcl-2 could protect neurons from ischemia. In that study, vector was delivered before the ischemia. However, for such gene therapy to be of clinical use, vectors must be protective even if delivered after the onset of the insult. In the present study, we show that an HSV vector expressing Bcl-2 protects striatal neurons when delivered after focal ischemia. Rats were exposed to middle cerebral artery occlusion for 1 hour, followed by reperfusion, and damage was assessed 48 hours later. Delivery of the Bcl-2 vector 30 minutes after reperfusion (i.e., 1.5 hours after ischemia onset) prevented any significant loss of virally-targeted neurons in the striatum. In contrast, in rats microinfused with a vector only expressing a reporter gene, a highly significant loss of neurons occurred. By 4 hours into the reperfusion period (5 hours after ischemia onset), delivery of the Bcl-2 vector was no longer protective. These data show the efficacy of postinsult gene therapy strategies for the brain, underline the finite length of this temporal therapeutic window, and support the growing evidence attesting to the neuroprotective potential of Bcl-2.

  View details for Web of Science ID A1997XR34500003

  View details for PubMedID 9270490

• Gene therapy for the nervous system SCIENTIFIC AMERICAN Ho, D. Y., Sapolsky, R. M. 1997; 276 (6): 116-120

  View details for Web of Science ID A1997WZ79800033

  View details for PubMedID 9163944

• Defective herpes simplex virus vectors expressing the rat brain stress-inducible heat shock protein 72 protect cultured neurons from severe heat shock JOURNAL OF NEUROCHEMISTRY Fink, S. L., Chang, L. K., Ho, D. Y., Sapolsky, R. M. 1997; 68 (3): 961-969

  Abstract

  Recently, preinduction of the heat shock response has been shown to protect CNS neurons undergoing various stressful insults, e.g., heat, ischemia, or exposure to excitotoxins. However, it is not known which of the proteins induced by the heat shock response mediate the protective effects. Previous correlative evidence points to a role for the highly stress-induced 72-kDa heat shock protein (hsp72). However, it is not known whether hsp72 expression alone can protect against a range of acute neuronal insults. We constructed a herpes simplex virus-1 vector carrying the rat brain stress-inducible hsp72 gene and the Escherichia coli lacZ (marker) gene. Infection with the vector caused hippocampal neurons to coexpress hsp72 and beta-galactosidase. Infection with a control vector led to marker gene expression only. Overexpression of hsp72 protected cultured hippocampal neurons against a heat shock but not against the metabolic toxin 3-nitropropionic acid or the excitotoxin glutamate. This is the first published report of protection following heat shock protein transfection in CNS neurons.

  View details for Web of Science ID A1997WJ84200009

  View details for PubMedID 9048741

• Inducible gene expression from defective herpes simplex virus vectors using the tetracycline-responsive promoter system MOLECULAR BRAIN RESEARCH Ho, D. Y., McLaughlin, J. R., Sapolsky, R. M. 1996; 41 (1-2): 200-209

  Abstract

  Herpes simplex virus-based amplicon vectors have been used for gene transfer into cultured neurons and the adult CNS. Since constitutive expression of a foreign gene or overexpression of an endogenous gene may have deleterious effects, the ability to control temporal expression would be advantageous. To achieve inducible gene expression, we have incorporated the tetracycline-responsive promoter system into amplicon vectors and showed, both in vitro and in vivo, that expression can be modulated by tetracycline. Using the firefly luciferase as the reporter gene, maximal repression by tetracycline in hippocampal cultures was about 50-fold. Withdrawal of tetracycline derepressed gene expression, reaching maximal levels within 10-12 h. In contrast, addition of tetracycline to cultures without prior tetracycline exposure inhibited gene expression rapidly; luciferase activity was reduced to less than 8% within 24 h. In adult rat hippocampus, vectors expressing luciferase or the Escherichia coli lacZ were repressed by tetracycline 9- and 60-fold, respectively. Maximum gene expression from the vectors occurred 2-3 days post-infection and declined thereafter. Such decline impeded further induction of expression by withdrawing tetracycline. This study demonstrates the feasibility of incorporating a powerful inducible promoter system into HSV vectors. The development of such an inducible viral vector system for gene transfer into the adult CNS might prove to be of experimental and therapeutic value.

  View details for Web of Science ID A1996VF39200026

  View details for PubMedID 8883953

• Energy and glutamate dependency of 3-nitropropionic acid neurotoxicity in culture EXPERIMENTAL NEUROLOGY Fink, S. L., Ho, D. Y., Sapolsky, R. M. 1996; 138 (2): 298-304

  Abstract

  3-Nitropropionic acid (3-NP) irreversibly inhibits the activity of the mitochondrial enzyme succinate dehydrogenase, leading to selective striatal lesions when administered in vivo. We studied the effects of 3-NP on dissociated cultures of neurons and glia with the following findings: (a) 3-NP killed cultured striatal neurons with a median lethal dose of 2.5 mM after 20 h of incubation in 20.0 mM glucose medium. Despite its selective toxicity in vivo, cultured striatal, hippocampal, septal, and hypothalamic neurons were similarly sensitive to 3-NP incubation. (b) 3-NP's effects were remarkably energy substrate dependent, with the median lethal dose dropping over an order of magnitude when glucose concentrations were lowered to 3.0 mM, a condition that was itself nontoxic. Cultures exposed to 3-NP had a far greater sensitivity to energy availability than those exposed to glutamate. (c) Recent work suggests that 3-NP toxicity may be partially mediated by excitotoxins. Our experiments show that neither kynurenic acid, a nonspecific glutamate receptor antagonist, nor the NMDA-receptor antagonist, DL-2-amino-7-phosphonoheptanoic acid, either in combination or alone, reduced 3-NP toxicity in striatal cultures. However, the noncompetitive NMDA antagonist MK-801 did attenuate 3-NP toxicity.

  View details for Web of Science ID A1996UF07800013

  View details for PubMedID 8620928

• Overexpression of the glucose transporter gene with a Herpes simplex viral vector protects striatal neurons against stroke JOURNAL OF CEREBRAL BLOOD FLOW AND METABOLISM Lawrence, M. S., Sun, G. H., Kunis, D. M., Saydam, T. C., Dash, R., Ho, D. Y., Sapolsky, R. M., Steinberg, G. K. 1996; 16 (2): 181-185

  Abstract

  Herpes simplex virus vectors bearing a glucose transporter (GT) gene and a marker gene were found to protect neurons against a 1-h focal ischemic insult. Rats receiving the GT vector v alpha22beta gal alpha4GT exhibited a 67.4 +/- 35.3% survival of virally targeted neurons in the ischemic hemisphere compared with the contralateral control (n = 7), whereas rats receiving a control vector exhibited only 32.8 +/- 17.9% survival (n = 9). This significant improvement in survival (105%, p=0.022) suggests that energy failure is an important contributor to the neuropathology of ischemic damage in the striatum, and that it can be alleviated by gene transfer. This is the first demonstration of protection against ischemic cerebral injury by the direct transfer of GT genes to neurons.

  View details for Web of Science ID A1996TW39300001

  View details for PubMedID 8594048

• Overexpression of bcl-2 with herpes simplex virus vectors protects CNS neurons against neurological insults in vitro and in vivo JOURNAL OF NEUROSCIENCE Lawrence, M. S., Ho, D. Y., Sun, G. H., Steinberg, G. K., Sapolsky, R. M. 1996; 16 (2): 486-496

  Abstract

  Previous studies have demonstrated that overexpression of the proto-oncogene bcl-2 can protect neuron and neuron-like cell lines from growth factor deprivation, calcium ionophores, glutamate excitotoxicity, hypoglycemia, free radicals, and lipid peroxidation. To determine whether Bcl-2 exhibits a similar protective effect in CNS neurons, we generated defective herpes simplex virus (HSV) vectors capable of overexpressing Bcl-2 in primary cultures and in the intact brain. Infection of hippocampal cultures with Bcl-2 vectors enhanced neuron survivorship after exposure to adriamycin, a potent oxygen radical generator. Furthermore, dichlorofluorescein measurements indicated that there was a significant reduction in the accumulation of oxygen radicals associated with this insult. Bcl-2 vectors also enhanced survival in cultured neurons after exposure to glutamate and hypoglycemia. Most significantly, the in vivo delivery of the vector protected neurons against adriamycin toxicity in the dorsal horn of the dentate gyrus and focal ischemia in the striatum.

  View details for Web of Science ID A1996TP51900007

  View details for PubMedID 8551333

• Herpes simplex viral vectors expressing bcl-2 are neuroprotective against focal ischemia In: Krieglstein J (ed.) Pharmacology of Cerebral Ischemia, Medpharm, Stuttgart Yenari M, Lawrence M, Sun G, Ho DY, Kunis D, Sapolsky R, Steinberg G 1996: 537-543
• Herpes simplex viral vectors expressing Bcl-2 are neuroprotective against focal cerebral ischemia 6th International Symposium on Pharmacology of Cerebral Ischemia Yenari, M. A., Lawrence, M. S., Sun, G. H., Ho, D. Y., Kunis, D. M., Sapolsky, R. M., Steinberg, G. K. WISSENSCHAFTLICHE verlagsgesellschaft mbh. 1996: 537–543

  View details for Web of Science ID A1996BH54J00053

• A herpes simplex virus vector overexpressing the glucose transporter gene protects the rat dentate gyrus from an antimetabolite toxin EXPERIMENTAL NEUROLOGY Dash, R., Lawrence, M., Ho, D., Sapolsky, R. 1996; 137 (1): 43-48

  Abstract

  The use of herpes simplex virus vectors offers an attractive means for the in vitro and in vivo transfer of novel genes into postmitotic neurons. Such an approach allows for the introduction of genes with the potential to protect neurons from necrotic insults. Toward that end, we have previously constructed a bicistronic herpes viral vector expressing the gene for the Glut-1 rat brain glucose transporter (GT), along with the Escherichia coli lacZ reporter gene. We observed that this vector enhances glucose uptake both in primary hippocampal cultures and in the hippocampus itself. Moreover, we have found that this vector will protect a variety of types of cultured neurons from necrotic insults and protect hippocampal neurons in vivo from seizure-induced damage. In the present report, we further demonstrate the neuroprotective potential of this GT-expressing vector. 3-Acetylpyridine, an electron transport uncoupler which is preferentially toxic to the dentate gyrus, was microinfused into the dorsal hippocampus of rats. Infection of dentate neurons with GT vectors at the time of exposure to the toxin significantly decreased damage, whereas infection with a physiologically neutral control vector did not. Moreover, there was a window of opportunity for this intervention, as microinfusion of the GT-expressing vector up to 1 h, but not 4 h, after the insult was still neuroprotective.

  View details for Web of Science ID A1996TQ62700005

  View details for PubMedID 8566211

• HERPES-SIMPLEX VIRUS VECTORS OVEREXPRESSING THE GLUCOSE-TRANSPORTER GENE PROTECT AGAINST SEIZURE-INDUCED NEURON LOSS PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA Lawrence, M. S., Ho, D. Y., Dash, R., Sapolsky, R. M. 1995; 92 (16): 7247-7251

  Abstract

  We have generated herpes simplex virus (HSV) vectors vIE1GT and v alpha 4GT bearing the GLUT-1 isoform of the rat brain glucose transporter (GT) under the control of the human cytomegalovirus ie1 and HSV alpha 4 promoters, respectively. We previously reported that such vectors enhance glucose uptake in hippocampal cultures and the hippocampus. In this study we demonstrate that such vectors can maintain neuronal metabolism and reduce the extent of neuron loss in cultures after a period of hypoglycemia. Microinfusion of GT vectors into the rat hippocampus also reduces kainic acid-induced seizure damage in the CA3 cell field. Furthermore, delivery of the vector even after onset of the seizure is protective, suggesting that HSV-mediated gene transfer for neuroprotection need not be carried out in anticipation of neurologic crises. Using the bicistronic vector v alpha 22 beta gal alpha 4GT, which coexpresses both GT and the Escherichia coli lacZ marker gene, we further demonstrate an inverse correlation between the extent of vector expression in the dentate and the amount of CA3 damage resulting from the simultaneous delivery of kainic acid.

  View details for Web of Science ID A1995RM72200024

  View details for PubMedID 7638175

• DEFECTIVE HERPES-SIMPLEX VIRUS VECTORS EXPRESSING THE RAT-BRAIN GLUCOSE-TRANSPORTER PROTECT CULTURED NEURONS FROM NECROTIC INSULTS JOURNAL OF NEUROCHEMISTRY Ho, D. Y., Saydam, T. C., Fink, S. L., Lawrence, M. S., Sapolsky, R. M. 1995; 65 (2): 842-850

  Abstract

  Because neurons are postmitotic, they are irreplaceable once they succumb to necrotic insults such as hypoglycemia, ischemia, and seizure. A paucity of energy can exacerbate the toxicities of these insults; thus, a plausible route to protect neurons from necrotic injury would be to enhance their glucose uptake capability. We have demonstrated previously that defective herpes simplex virus (HSV) vectors overexpressing the rat brain glucose transporter (GT) gene (gt) can enhance glucose uptake in adult rat hippocampus and in hippocampal cultures. Furthermore, we have observed that such vectors can maintain neuronal metabolism during hypoglycemia and reduce kainic acid-induced seizure damage. In this study, we have developed bicistronic vectors that coexpressed gt and Escherichia coli lacZ as a reporter gene, which allows us to identify directly neurons that are infected with the vectors. Overexpression of GT from these vectors protected cultured hippocampal, spinal cord, and septal neurons against various necrotic insults, including hypoglycemia, glutamate, and 3-nitropropionic acid. Our observations demonstrate the feasibility of using HSV vectors to protect neurons from necrotic insults. Although this study has concentrated on the delivery of gt, other genes with therapeutic or protective capability might also be used.

  View details for Web of Science ID A1995RJ65700048

  View details for PubMedID 7616244

• HERPES-SIMPLEX VIRUS VECTOR SYSTEM - ANALYSIS OF ITS IN-VIVO AND IN-VITRO CYTOPATHIC EFFECTS JOURNAL OF NEUROSCIENCE METHODS Ho, D. Y., Fink, S. L., Lawrence, M. S., Meier, T. J., Saydam, T. C., Dash, R., Sapolsky, R. M. 1995; 57 (2): 205-215

  Abstract

  With its natural propensity to infect and establish life-long latency in neurons, herpes simplex virus type 1 (HSV-1) has been successfully employed by various laboratories as vectors for gene transfer into neurons. However, analysis of its cytopathic effects in vivo and in vitro has been limited. In this study, we examined the cytopathic effects of 2 HSV-1 alpha 4 mutants (ts756 and d120) on adult rat hippocampus and striatum and of d120 on hippocampal neurons in culture. We assessed damage by stringent counting of surviving neurons after infection and demonstrated that while neither ts756 nor d120 infection resulted in any gross anatomical or behavioral changes of the animals, ts756, but not d120, produced a significant amount of damage in the CA4 cell field and dentate gyrus of the hippocampus. Thus, since crude examination is insufficient to detect subtle but significant degrees of neuron loss, the cytopathic effects of HSV or any vector system must be carefully analyzed. Furthermore, we also observed that uninfected cell lysates damaged neurons, both in vivo and in vitro. This cytotoxicity occurred within the first 24 h post-inoculation and probably arose through the activation of glutamate receptors. For the preparation of HSV vectors, purification of the virus from soluble cellular components by a simple pelleting step can significantly decrease such acute toxicity.

  View details for Web of Science ID A1995QU14500010

  View details for PubMedID 7609584

• MULTIPLE VECTORS EFFECTIVELY ACHIEVE GENE-TRANSFER IN A MURINE CARDIAC TRANSPLANTATION MODEL - IMMUNOSUPPRESSION WITH TGF-BETA-1 OR VIL-10 TRANSPLANTATION Qin, L. H., Chavin, K. D., Ding, Y. Z., Favaro, J. P., Woodward, J. E., Lin, J. X., Tahara, H., Robbins, P., Shaked, A., Ho, D. Y., Sapolsky, R. M., Lotze, M. T., Bromberg, J. S. 1995; 59 (6): 809-816

  Abstract

  The application of gene transfer techniques to organ transplantation offers the potential for modulation of immunity directly within an allograft without systemic side effects. Expression vectors and promoter elements are important determinants of gene transfer and expression. In this study, various vectors (naked plasmid DNA, retroviral vector, herpes simplex viral vector, and adenoviral vector) with various promoters (RSV-LTR, SV40, MuLV-LTR, HCMVie1) were directly compared to demonstrate the successful gene transfer and expression of beta-galactosidase in murine myoblasts in vitro and within murine heterotopic, nonvascularized cardiac isografts or allografts in vivo. Expression of transferred genes was not toxic to cells and strength of expression varied according to the type of vector. Plasmid DNA was expressed in myocytes, retroviral vector was expressed in the graft infiltrating cells, and herpes simplex and adenoviral vectors were expressed in both myocytes and graft-infiltrating cells. Preliminary studies evaluated the ability of these vectors to deliver immunologically important signals. Allografts injected with pSVTGF-beta 1, a plasmid-encoding transforming growth factor beta 1 (TGF-beta 1) under the control of the SV40 promoter, showed significant prolongation of graft survival of 26.3 +/- 2.5 days compared with 12.6 +/- 1.1 days for untreated allografts, and 12.5 +/- 1.5 days for the allografts injected with control plasmid (P < 0.05). Allografts injected with MFG-vIL-10, a retroviral vector encoding viral interleukin-10 under the control of the MuLV-LTR, showed prolongation of graft survival of 36.7 +/- 1.3 days versus 12.6 +/- 1.1 days for the untreated allograft, and 13.5 +/- 2.0 days for the allografts injected with control retroviral vector (P < 0.001). Both vectors were transcriptionally active in vivo and did not appear to have toxic effects. Gene therapy for transplantation can induce transient expression of immunologically relevant molecules within allografts that impede immune activation while avoiding the systemic toxicity of conventional immunosuppression.

  View details for Web of Science ID A1995QQ42500002

  View details for PubMedID 7701573

• Use of herpes simplex virus vectors for protection from necrotic neuron death In: Kaplitt M, Loewy A (eds.), Viral Vectors, Academic Press Ho DY, Lawrence M, Meier T, Fink S, Dash R, Saydam T, Sapolsky R 1995: 133-155
• Necrotic neuron death, its exacerbation by stress, and its diminution by gene transfer approaches In: Ottoson D, Bartfai T, Hokfelt T, Fuxe K (eds.) Challenges and Perspectives in Neuroscience, Wenner-Gren International Series, Pergamon Sapolsky R, Ho DY 1995: 179-210
• AMPLICON-BASED HERPES-SIMPLEX VIRUS VECTORS METHODS IN CELL BIOLOGY, VOL 43 Ho, D. Y. 1994; 43: 191-210

  View details for Web of Science ID A1994BB61Z00009

  View details for PubMedID 7823862

• ALTERING CENTRAL-NERVOUS-SYSTEM PHYSIOLOGY WITH A DEFECTIVE HERPES-SIMPLEX VIRUS VECTOR EXPRESSING THE GLUCOSE TRANSPORTER GENE PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA Ho, D. Y., Mocarski, E. S., Sapolsky, R. M. 1993; 90 (8): 3655-3659

  Abstract

  Because of their postmitotic nature, neurons are difficult subjects for gene transfer. To circumvent this, we have used a defective herpes simplex virus vector to overexpress the rat brain glucose transporter (GT) gene under the control of the human cytomegalovirus ie1 promoter. This vector, designated vIE1GT, was propagated using a herpes simplex virus type 1 temperature-sensitive mutant, ts756. GT expressed from vIE1GT was readily immunoprecipitated from membrane fractions of vIE1GT-infected Vero cells. By using indirect double immunofluorescence techniques, vIE1GT was shown to be capable of enhancing GT expression in cultured hippocampal neurons and glia. Glucose transport in such vIE1GT-infected cultures was increased approximately 2-fold relative to controls. The efficacy of this system in vivo was then tested by microinjection of vIE1GT into adult rat hippocampus. When examined 2 days later, GT expression from vIE1GT was demonstrated in hippocampal neurons by in situ hybridization; a small but significant increase in glucose transport was detected in tissue immediately surrounding the injection site by 2-deoxy[14C]glucose uptake and autoradiography. Such injections did not cause marked cytopathology. Thus, this approach can be used to alter central nervous system physiology in vitro and in vivo.

  View details for Web of Science ID A1993KX81600112

  View details for PubMedID 8386379

  View details for PubMedCentralID PMC46360

• NEUTRALIZING EPITOPES ON HERPES-SIMPLEX VIRUS-1-EXPRESSED ROTAVIRUS-VP7 ARE DEPENDENT ON COEXPRESSION OF OTHER ROTAVIRUS PROTEINS VIROLOGY Dormitzer, P. R., Ho, D. Y., MACKOW, E. R., Mocarski, E. S., Greenberg, H. B. 1992; 187 (1): 18-32

  Abstract

  We constructed a recombinant thymidine kinase-negative herpes simplex virus type 1 (HSV-1) that expressed the rotavirus major outer capsid glycoprotein, VP7. In the recombinant HSV-1, a promoter from the 5' noncoding region of the HSV-1 glycoprotein B locus regulated the expression of VP7 as a HSV-1 gamma 1 gene product. HSV-1-expressed VP7 resembled rotavirus-expressed VP7 in its SDS-PAGE mobility, high mannose-type glycosylation, disulfide bonding, perinuclear to cytoplasmic localization, intracellular retention, and reactivity with polyclonal antisera and nonneutralizing antibodies. Unlike rotavirus-expressed VP7, HSV-1-expressed VP7 lacked several neutralizing epitopes by immuno-histochemical staining and by ELISA. One neutralizing epitope identified on HSV-1-expressed VP7 by ELISA was masked by paraformaldehyde fixation of recombinant HSV-1- but not rotavirus-infected cells. Neutralizing epitopes were restored to HSV-1-expressed VP7 by coinfection of cells with the HSV-1 recombinant and a heterologous rotavirus that lack the neutralizing epitopes. The recovered neutralizing epitopes were detected on double-shelled rotavirus particles produced in the coinfected cells. This study indicates that the formation of several neutralizing epitopes on rotavirus VP7 requires interaction of VP7 with other rotavirus proteins. In addition, HSV-1 was a useful vector for studying the localization, processing, and antigenicity of an RNA virus glycoprotein.

  View details for Web of Science ID A1992HD62800003

  View details for PubMedID 1371025

• HERPES-SIMPLEX VIRUS LATENCY - MOLECULAR ASPECTS PROGRESS IN MEDICAL VIROLOGY Ho, D. Y. 1992; 39: 76-115

  View details for Web of Science ID A1992HP43100003

  View details for PubMedID 1317601

• HERPES-SIMPLEX VIRUS LATENT RNA (LAT) IS NOT REQUIRED FOR LATENT INFECTION IN THE MOUSE PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA Ho, D. Y., Mocarski, E. S. 1989; 86 (19): 7596-7600

  Abstract

  During latent infection by herpes simplex virus (HSV), an abundant latency-associated transcript (LAT) that is antisense to a predominant viral alpha gene (ICP0) is found localized in the nucleus of sensory neurons. We disrupted both copies of the LAT gene in the HSV-1 genome by insertion of the Escherichia coli lacZ gene under LAT promoter control. The resulting recombinant virus, RH142, does not express any detectable LAT in either latently or productively infected cells, although beta-galactosidase expression is readily detectable in sensory neurons of latently infected mice. Expression was first detectable 3 days postinoculation and continued at approximately the same level for the entire experimental period (56 days). beta-Galactosidase expression was not detectable at any time during RH142 replication in Vero cells. Thus, the kinetics of expression and cell-type specificity of the LAT gene are distinct from other HSV-1 genes that are expressed during productive growth. When latently infected trigeminal ganglia were explanted, RH142 reactivated from latency with the kinetics and an efficiency indistinguishable from the parental wild-type virus. These studies argue against any possible antisense regulatory mechanism of LAT in the regulation of viral gene expression or any role of LAT-encoded protein during the establishment or maintenance of latency in the mouse.

  View details for Web of Science ID A1989AT78200066

  View details for PubMedID 2552449

• BETA-GALACTOSIDASE AS A MARKER IN THE PERIPHERAL AND NEURAL TISSUES OF THE HERPES-SIMPLEX VIRUS-INFECTED MOUSE VIROLOGY Ho, D. Y., Mocarski, E. S. 1988; 167 (1): 279-283

  Abstract

  We have inserted a modified Escherichia coli lacZ gene, placed under the control of herpes simplex virus alpha 4 or beta 8 regulatory signals, into the HSV-1 genome disrupting the viral thymidine kinase gene. Using beta-galactosidase as an in situ indicator of viral gene expression, we detected expression from these recombinant HSV in dermal and neural tissues of the BALB/c mouse. Our detection of beta-galactosidase expression in neuronal cells indicates that TK-deficient viruses are capable of invading mouse neuronal cells and expressing up to the beta class of gene product.

  View details for Web of Science ID A1988Q895500033

  View details for PubMedID 2847416