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Biomedical subjects

S Weissman

Publications and source records attributed to S Weissman.

At least 19 recordsLinked to original sources
PubMed2006

Response to hepatitis A vaccine in HIV-positive patients.

The USPHS/IDSA guidelines for Prevention of Opportunistic Infections in Persons with human immunodeficiency virus (HIV) recommends that all susceptible HIV+ patients at increased risk for hepatitis A virus (HAV) or with chronic liver disease, be vaccinated against HAV. Immune response to HAV vaccine has not been well studied in HIV+ patients. In particular, there is little information in the literature regarding the effect and relationship of the CD4 count and the immune response in HIV patients. A retrospective analysis of HIV+ patients who received HAV vaccine was performed, and the antibody response to HAV (anti-HAV) measured. Univariate and multivariate analyses were performed to determine predictors of response to vaccine administration. Of the 503 patients evaluated, 138 patients completed their HAV vaccination series and 48% of them had postvaccine anti-HAV positive results (responders). There was no difference in age, race, antiretroviral therapy use, or hepatitis C virus exposure between responders and nonresponders. In univariate analysis, responders were more likely to be female (40.3%vs 21.1%, P = 0.01), have a higher CD4 count at vaccine (508.6 cells/mm3 vs 344.3 cells/mm3, P = 0.001) and marginally lower viral load at vaccine (2.65 log copies vs 2.94 log copies, P = 0.07). Multivariate analysis showed that female gender and higher CD4 count at vaccine were independent predictors of response to vaccine. Forty-eight per cent of our HIV+ patients responded to HAV vaccine administration. This is much lower than reported rates of 100% in HIV-negative patients. Female gender and CD4 count at vaccine, but not CD4 nadir, predicted response to vaccine.

Adult↗
PubMed2004

Association of hypocholesterolaemia with hepatitis C virus infection in HIV-infected people.

OBJECTIVE: To study the impact of hepatitis C virus (HCV) status on serum cholesterol levels in HIV-infected patients. METHODS: We retrospectively analysed data from the 881 participants of the Veterans Ageing Cohort 3 Site Study. Four different models were constructed using total cholesterol, low-density lipid (LDL) cholesterol, high-density lipid (HDL) cholesterol and triglycerides as dependent variables. The relevant covariates included HCV antibody status, HIV medication class, CD4 count, HIV viral load, glucose level, lipid-lowering drug use, gender, race, age, liver function test results, ethanol use, drug use, and HIV exposure category. Variables excluded from the final model included niacin use, gender, race, age, current ethanol use, and HIV exposure category. RESULTS: Of the 881 HIV-positive patients enrolled in the study, 700 (79%) were screened for HCV antibody, with 300 (42.8%) HCV antibody positive and 400 (57.2%) HCV antibody negative. A positive HCV antibody status was independently associated with lower total cholesterol levels (P=0.001) and LDL cholesterol levels (P<0.001) but not with lower HDL cholesterol or triglyceride levels. HCV-positive patients had predicted LDL levels 19 mg/dL lower than those of HCV-negative subjects. HCV infection was also associated with a decreased use of lipid-lowering medication, and protease inhibitor use was associated with increased LDL and total cholesterol levels. CONCLUSIONS: HCV infection has been associated with lower cholesterol levels in HIV-negative individuals, and the same appears to be true with HIV-infected patients. This is an interesting finding given that HCV particles bind to LDL receptors in vitro and also because HCV-lipid interactions appear to be important in the HCV replication cycle.

Antiretroviral Therapy, Highly Active↗
PubMed2001

Mesenchymal stem cells are capable of homing to the bone marrow of non-human primates following systemic infusion.

OBJECTIVE: The human bone marrow contains mesenchymal stem cells capable of differentiating along multiple mesenchymal cell lineages. Using a non-human primate model, we sought to determine whether the systemic infusion of baboon-derived mesenchymal stem cells was associated with toxicity and whether these cells were capable of homing to and persisting within the bone marrow. MATERIALS AND METHODS: Five baboons (Papio anubis) were administered lethal irradiation followed by intravenous autologous hematopoietic progenitor cells combined with either autologous (n = 3) or allogeneic (n = 2) mesenchymal stem cells that had been expanded in culture. In four of these baboons, the mesenchymal stem cells were genetically modified with a retroviral vector encoding either the enhanced green fluorescent protein gene (n = 3) or the human placental alkaline phosphatase gene (n = 1) for tracking purposes. A sixth animal received only intravenous gene marked autologous mesenchymal stem cells but no hematopoietic stem cells or conditioning irradiation. RESULTS: Following culture, baboon mesenchymal stem cells appeared morphologically as a homogeneous population of spindle-shaped cells that were identified by the monoclonal antibodies SH-3 and SH-4. These cells did not express the hematopoietic markers CD34 or CD45. Baboon mesenchymal stem cells isolated from primary culture were capable of differentiating along both adipogenic and osteogenic lineages. There was no acute or chronic toxicity associated with the intravenous infusion of mesenchymal stem cells. In all five recipients of gene marked mesenchymal stem cells, transgene was detected in post-transplant bone marrow biopsies. In two animals receiving autologous mesenchymal stem cells, including the one non-conditioned recipient, transgene could be detected over 1 year following infusion. In one recipient of allogeneic gene marked mesenchymal stem cells, transgene was detected in the bone marrow at 76 days following infusion. CONCLUSION: These data demonstrate that baboon mesenchymal stem cells: 1) are not associated with significant toxicity when administered intravenously, 2) are capable of homing to the bone marrow following intravenous infusion, and 3) have the capacity to establish residence within the bone marrow for an extended duration following systemic administration.

Alkaline Phosphatase↗
PubMed2001

General medical and psychiatric comorbidity among HIV-infected veterans in the post-HAART era.

We examined the prevalence of HIV, general medical, and psychiatric comorbidities by age based on a recent multisite cohort of HIV infected veterans receiving care: the Veterans with HIV/AIDS 3 Site Study (VACS 3). VACS 3 includes 881 adult patients with HIV infection enrolled between June 1999 and July 2000. Providers reported their patients' CDC-defined HIV comorbidities, general medical comorbidities (based on Duke and Charlson comorbidity scales), and psychiatric comorbidity. Mean age of participants was 49 years and 54% were African-American. The most common HIV comorbidities were oral candidiasis (21%), peripheral neuropathy (16%), and herpes zoster (16%). The most common general medical comorbidities included chemical hepatitis (53%), hypertension (24%), and hyperlipidemia (17%). The mean number of HIV and general medical comorbidities experienced by patients were respectively 1.1 and 1.4 (P < .001). Older (> or = 50 years) HIV-infected patients experienced a greater number of general medical comorbidities than those < 50 years (respectively 1.7 versus 1.2, P < .001). There was no significant difference in mean HIV comorbidity number by age. Based on patient report, 46% had significant depressive symptoms (> or = 10 on 10-item CES-D) and 21% reported at-risk drinking (> or = 8 on AUDIT). Providers reported 32% of patients had anxiety, 4% mania, 4% schizophrenia, and 11% cognitive impairment/dementia. General medical and psychiatric comorbidities constituted a higher disease burden for HIV-infected veterans than HIV comorbidities. Whether these comorbidities are due to antiretroviral drug toxicity or are age or lifestyle-associated conditions, the substantial prevalence of these "non-HIV" comorbidities suggest an important role for general medical and psychiatric management of HIV-infected patients.

AIDS-Related Opportunistic Infections↗
PubMed2001

Veterans aging cohort three-site study (VACS 3): overview and description.

Outcomes for middle-aged and older individuals with HIV infection are poor, and are likely to be mediated by age-related differences in risks and resources (access to care, relationship with the provider, comorbid conditions, health habits, and changes brought about by aging). The goal of the Veterans Aging Cohort Three-Site Study (VACS 3) is to study the influence of age and mediating factors on outcomes with HIV in order to identify mutable mediators of poorer outcomes. VACS 3 is an observational, longitudinal study. Data sources include patient and provider surveys and electronic medical data collected at baseline and 12-month follow-up from the Infections Disease Clinics at three Veterans Affairs Medical Centers (Cleveland, OH, Houston, TX, and Manhattan, NY). Trained Survey Coordinators at each site determined which patients are HIV infected, obtained consent, and asked the patient to complete a questionnaire. The primary provider also completed a questionnaire. Twelve-month follow-up will be completed July 2001. Of all veterans with HIV seen in these clinics 85% (881) have consented and enrolled. Of the 881 corresponding provider surveys, 92% were completed. Mean age is 49; 55% are African-American; 38% of the sample were men who have sex with men; and less than 2% are women. Almost a third (32%) have been without a permanent address. Complimentary or alternative therapies are common as are the use of cigarettes, alcohol, and illicit drugs. The majority (87%) of the patients are taking multiple antiretroviral medications. The median CD4 count is 331 mm(3), and the median viral load was 714 copies/ml. There is substantial variation by site. Veterans with HIV infection have characteristics that will likely become more prevalent among HIV-infected persons in the United States: they are older, commonly suffer comorbid disease, and are members of minority populations. VACS 3 may help inform the design of future clinical interventions to improve outcomes for people aging with HIV.

Aged↗
PubMed2001

Development and validation of a self-completed HIV symptom index.

Traditional, open-ended provider questions regarding patient symptoms are insensitive. Better methods are needed to measure symptoms for clinical management, patient-oriented research, and adverse drug-event reporting. Our objective was to develop and initially validate a brief, self-reported HIV symptom index tailored to patients exposed to multidrug antiretroviral therapies and protease inhibitors, and to compare the new index to existing symptom measures. The research design was a multistage design including quantitative review of existing literature, qualitative and quantitative analyses of pilot data, and quantitative analyses of a prospective sample. Statistical analyses include frequencies, chi-square tests for significance, linear and logistic regression. The subjects were from a multisite convenience sample (n = 73) within the AIDS Clinical Trials Group and a prospective sample from the Cleveland Veterans Affairs Medical Center (n = 115). Measures were patient-reported symptoms and health-related quality of life, physician-assessed disease severity, CD4 cell count, and HIV-1 RNA viral quantification. A 20-item, self-completed HIV symptom index was developed based upon prior reports of symptom frequency and bother and expert opinion. When compared with prior measures the index included more frequent and bothersome symptoms, yet was easier to use (self-report rather than provider interview). The index required less than 5 minutes to complete, achieved excellent completion rates, and was thought comprehensive and comprehensible in a convenience sample. It was further tested in a prospective sample of patients and demonstrated strong associations with physical and mental health summary scores and with disease severity. These associations were independent of CD4 cell count and HIV-1 RNA viral quantification. This 20-item HIV symptom index has demonstrated construct validity, and offers a simple and rational approach to measuring HIV symptoms for clinical management, patient-oriented research, and adverse drug reporting.

Antiretroviral Therapy, Highly Active↗
PubMed2001

Patient- and provider-reported adherence: toward a clinically useful approach to measuring antiretroviral adherence.

We seek to develop a clinically useful measure of antiretroviral medication adherence. Because there is no gold standard for adherence, we will assess the clinical validity of patient- and provider-reported adherence by the strength of their expected associations with current viral load, depressive symptoms, alcohol and illicit drug use, and homelessness. The Veterans Aging Cohort 3 Site Study (VACS 3) is a multisite study of 881 patients at Cleveland, Houston, and Manhattan Veterans Affairs health care systems. Data was collected on adherence using patient report and provider assessment; depressive symptoms using the Center for Epidemiological Studies Depression (CESD) and provider assessment; alcohol use using the Alcohol Use Disorders Identification Test (AUDIT) and provider assessment; and homelessness using patient report only. Viral load was collected from electronic laboratory data. Although agreement between providers and patients about the patient's adherence was not better than chance (61%; weighted kappa =.07), both patient and provider-reported adherence were related to viral load (P <.001), current alcohol use (P <.01), current drug use (P <.01), and depressive symptoms (P <.001). Patient-reported adherence was also associated with homelessness (P <.05). In multivariate regression models, provider assessment of adherence demonstrated independent associations with viral load (P <.001), current alcohol use (P <.001), current drug use (P <.001), and depressive symptoms (P <.001) after adjustment for the patient's report of adherence (also significantly associated). The consistent and largely independent association between patient and provider reported adherence and a range of variables previously shown to be associated with adherence suggests that patient- and provider-reported adherence independently measure actual adherence. Future work will explore how patient- and provider-reported adherence might best be combined, and whether the measure may be further enhanced with pharmacy refill data.

Antiretroviral Therapy, Highly Active↗
PubMed2000

Cloning and characterization of two mouse genes with homology to the yeast Sir2 gene.

The yeast Sir2 gene encodes a protein (Sir2p) that plays an essential role in silencing regulation at mating-type loci, rDNA, and telomeres. Recent studies have also shown that the protein participates in cell cycle regulation, DNA double-strand break repair, meiotic checkpoint control, and histone deacetylation. Overexpression of wildtype Sir2p in yeast resulted in an extended life span but mutant Sir2p shortened the life span, suggesting its function in aging processes. Sir2p is evolutionarily conserved from prokaryotes to higher eukaryotes. However, its function(s) in mammals remains unknown. To investigate Sir2p function(s) in mice, we cloned and characterized two mouse Sir2-like genes. Our results revealed that the two mouse Sir2-like proteins (mSIR2L2 and mSIR2L3) are most similar to the human Sir2-like proteins SIR2L2 and SIR2L3, respectively. Sir2 core domains are highly conserved in the two proteins and yeast Sir2p; however, the intracellular localizations of both mSIR2L2 and mSIR2L3 differ from that of yeast Sir2p and from one another. The two mouse genes have completely different genomic structures but were mapped on the same chromosome. It seems that the two mouse proteins, though they have Sir2 conserved domains, may function differently than yeast Sir2p.

Amino Acid Sequence↗
PubMed1999

The influence of cigarette smoking on cytokine levels in patients with inflammatory bowel disease.

Anecdotal reports suggest that smoking may be beneficial for patients with inflammatory bowel disease (IBD) as nicotine may act through inflammatory mediators within the colonic mucosa. Furthermore, there is increasing evidence that cytokines play a pathologic role in IBD. Our aim was to determine the effects of cigarette smoking on cytokine levels in the colonic mucosa of patients with and without IBD. Mucosal biopsies were obtained from 10 patients with Crohn's disease (CD), 10 with ulcerative colitis (UC), and 10 healthy controls. Five of 10 patients in each of the three groups were smokers and five were nonsmokers. Concentrations of interleukin (IL)-1beta, IL-2, IL-6, and IL-8 were determined using enzyme-linked immunosorbent assay (ELISA). Cytokine levels of smokers were compared with nonsmokers in each group and with controls. Results were analyzed using the Mann-Whitney test; significance was set at p<0.05. The concentration of IL-8 was significantly higher in healthy controls who smoke compared with nonsmokers and significantly reduced in smokers with CD compared with nonsmokers with CD. Moreover, concentrations of IL-1beta and IL-8 were significantly reduced in smokers with UC compared with nonsmokers with UC. Smokers had significantly elevated levels of IL-8 in the colonic mucosa. Smokers with IBD had a significant reduction in cytokine levels; specifically, IL-1beta and IL-8 for patients with UC and IL-8 for patients with CD. Further studies are warranted to determine if this reduction in cytokine levels is histologically and clinically significant.

Case-Control Studies↗