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Biomedical subjects

D Katzenstein

Publications and source records attributed to D Katzenstein.

At least 19 recordsLinked to original sources
PubMed2002

Reduced intraepidermal nerve fiber density in HIV-associated sensory neuropathy.

OBJECTIVE: To explore the relationship between intraepidermal nerve fiber (IENF) density in HIV-associated sensory neuropathy (HIV-SN) to measurements of neuropathy severity and progression of HIV disease. BACKGROUND: SN affects 30% of individuals with AIDS, and treatment is often ineffective. Recombinant human nerve growth factor (rhNGF) has been proposed as a trophic factor for unmyelinated nerve fibers injured in HIV-SN, and a clinical trial has recently concluded. Skin biopsy with IENF density determination has emerged as a diagnostic test for patients with small-fiber sensory neuropathy. METHODS: Sixty-two of the 270 patients with HIV-SN who participated in the trial of rhNGF were included in a substudy examining epidermal nerve fibers. IENF density was compared with neuropathic pain intensity (measured with the Gracely Pain Scale), patient and physician global pain assessments, quantitative sensory testing, CD4 counts, and plasma HIV RNA levels both at baseline and at conclusion of the placebo-controlled phase. RESULTS: IENF density was inversely correlated with neuropathic pain as measured by patient (p = 0.004) and physician (p = 0.05) global pain assessments, but not using the Gracely Pain Scale. Decreased IENF density at the distal leg was associated with lower CD4 counts and higher plasma HIV RNA levels. IENF density measurements were stable over time. CONCLUSIONS: IENF loss at the distal leg is associated with increased neuropathic pain, lower CD4 counts, and higher plasma viral load in HIV-SN. The robustness of the longitudinal measurement of IENF density supports its use in future longitudinal studies and clinical trials.

Acquired Immunodeficiency Syndrome↗
PubMed2002

Serotyping HIV-1 with V3 peptides: detection of high avidity antibodies presenting clade-specific reactivity.

The main objective of the present study was to assess the specificity and sensitivity of a modified assay using short synthetic peptides of the V3 region of HIV-1 gp120, which is the main target for neutralizing antibodies. Results from an enzyme immunoassay (EIA) employing a panel of synthetic peptides of HIV-1 subtypes and using urea washes to detect high avidity antibodies (AAV3) were compared with those obtained by the heteroduplex mobility assay and DNA sequencing. The EIA correctly typed 100% of subtype B (sensitivity = 1.0; specificity = 0.95), 100% of HIV-1 E samples (sensitivity = 1.0; specificity = 1.0), and 95% of subtype C specimens (sensitivity = 0.95; specificity = 0.94). In contrast, only 50% of subtype A (sensitivity = 0.5; specificity = 0.95), 60% of subtype D (sensitivity = 0.6; specificity = 1.0), and 28% of subtype F samples (sensitivity = 0.28; specificity = 0.95) were correctly identified. This approach was also able to discriminate in a few samples antibodies from patients infected with B variants circulating in Brazil and Thailand that reacted specifically. The assays described in this study are relatively rapid and simple to perform compared to molecular approaches and can be used to screen large numbers of serum or plasma samples. Moreover, the classification in subtypes (genotypes) may overestimate HIV-1 diversity and a classification into serotypes, based on antigenic V3 diversity or another principal neutralization domain, may be more helpful for vaccine development and identification of variants.

Amino Acid Sequence↗
PubMed2001

Long-term treatment with recombinant nerve growth factor for HIV-associated sensory neuropathy.

HIV-associated distal sensory polyneuropathy (DSP) is a common complication of AIDS. No effective treatment is available. The authors investigated the long-term effect (48 weeks) of the neurotrophin nerve growth factor (NGF) in an open-label study of 200 subjects with HIV-associated DSP. Similar to their previously reported double-blind study, the authors showed that NGF was safe and well tolerated and significantly improved pain symptoms. However, there was no improvement of neuropathy severity as assessed by neurologic examination, quantitative sensory testing, and epidermal nerve fiber density.

Acquired Immunodeficiency Syndrome↗
PubMed2001

Phenotypic hypersusceptibility to non-nucleoside reverse transcriptase inhibitors in treatment-experienced HIV-infected patients: impact on virological response to efavirenz-based therapy.

BACKGROUND: Enhanced susceptibility to non-nucleoside reverse transcriptase inhibitors (NNRTI) was recently described in association with increased resistance to nucleoside analogs (nucleoside reverse transcriptase inhibitors; NRTI). OBJECTIVES: To determine the prevalence of NNRTI hypersusceptibility, the genotypic correlates, and its impact on virologic response to efavirenz-based salvage therapy. METHODS: Genotype and phenotype testing was performed retrospectively on baseline isolates from 30 patients who received salvage therapy containing efavirenz. NNRTI hypersusceptibility was defined as a 50% inhibitory concentration (IC(50)) of < 0.5 that of the wild-type control. RESULTS: Eight isolates had major NNRTI mutations. Among the 22 isolates with no major NNRTI mutations, 11 (50%) were hypersusceptible to efavirenz, 10 (45%) to delavirdine, and eight (36%) to nevirapine. Among eight isolates with NNRTI mutations, NNRTI resistance was present, but at lower than expected levels. The number of NRTI mutations was correlated inversely with the fold decrease in susceptibility to efavirenz (Spearman's rho, -0.57; P = 0.005), delavirdine (rho, -0.43; P = 0.04), and nevirapine (rho, -0.69; P < 0.001). Excluding subjects with NNRTI mutations, subjects with efavirenz hypersusceptibility at baseline had significantly better virologic suppression over 24 weeks than those without efavirenz hypersusceptibility (P < 0.001). CONCLUSION: NNRTI hypersusceptibility is common in heavily treated but NNRTI naive patients and is related directly to NRTI resistance mutations. Among patients receiving efavirenz-containing regimens, NNRTI hypersusceptibility was associated with an improved virologic outcome after 24 weeks of therapy. A reversal of phenotypic resistance was seen in patients with NNRTI mutations in the presence of multiple NRTI mutations, but no obvious virologic benefit of this phenomenon was seen in this study.

Alkynes↗
PubMed2001

Prescribing practices and attitudes toward giving children antibiotics.

OBJECTIVE: To investigate whether overprescribing is common in treatment of pediatric upper respiratory infections and to examine factors that influence prescribing antibiotics for children. DESIGN: A random, stratified sample of practising family physicians was surveyed with a mailed questionnaire. Initial nonresponders were mailed a second questionnaire. SETTING: British Columbia. PARTICIPANTS: A total of 608 general and family physicians. Response rate was 64%; 392/612 surveys were completed. MAIN OUTCOME MEASURES: Physicians' self-reported prescribing practices and knowledge of and attitudes toward using antibiotics for children's upper respiratory tract infections. RESULTS: Relative to treatment guidelines developed for the study, most physicians responded appropriately to the cough (94%) and lobar pneumonia (99.1%) vignettes. More than half the physicians (56.5%) reported they would immediately prescribe antibiotics for tympanic membrane dysfunction, and 79.4% indicated they would prescribe antibiotics for pharyngitis without obtaining a laboratory culture. Approximately 25% of physicians in the study did not believe that prior antibiotic use increased personal risk for acquiring drug-resistant infection, and 23.1% did not believe that antibiotic use was an important factor in promoting resistance in their communities. CONCLUSION: Education in current treatment of pediatric upper respiratory tract illnesses and antimicrobial drug resistance is required. The high response to the questionnaire (64%) and the many requests from physicians to receive the project's educational materials (45%) indicate a high level of interest in this subject.

Age Factors↗
PubMed2000

Prenatal transmission of subtype C HIV-1 in Zimbabwe: HIV-1 RNA and DNA in maternal and cord blood.

Maternal and cord samples from HIV-seropositive women and their infants in Zimbabwe, where subtype C is the predominant strain of HIV, were analyzed to determine the frequency of detection of HIV RNA and DNA. HIV RNA was detected in 90% of maternal and in 38% of cord plasma at levels at least 25% of maternal plasma. Heteroduplex mobility assays and sequencing of virus envelope (C2-V5) demonstrated closely related, but unique, subtype C viruses in maternal and cord RNA, and a significantly greater frequency of cord viremia among women with homogenous, compared with heterogeneous viral envelope RNA. Quantification of RNA, measures of envelope viral diversity, and phylogenetic analysis of maternal and cord plasma RNA provide evidence for the frequent exposure and potential transmission of HIV from mother to infant before birth.

Adult↗
PubMed2000

Competing drug-drug interactions among multidrug antiretroviral regimens used in the treatment of HIV- infected subjects: ACTG 884.

OBJECTIVE: To evaluate the steady state concentrations of saquinavir, ritonavir, nelfinavir, delavirdine, and adefovir in six different three- and four-drug combination regimens. DESIGN: Randomized, partially double-blinded, multicenter study in a population of indinavir-experienced subjects with virologic failure. The first seven subjects enrolled in each of the six treatment arms from 10 participating sites were entered into this pharmacokinetic evaluation. SETTING: Multicenter study of the AIDS Clinical Trials Group (ACTG). PATIENTS: HIV-infected subjects. INTERVENTIONS: A 12-hour pharmacokinetic study was conducted after 2 weeks of drug administration. MAIN OUTCOME MEASURES: Area under the concentration-time curve with statistical comparisons to evaluate the effect of the second protease inhibitor and the effect of the non-protease inhibitors. RESULTS: There was no difference in saquinavir concentrations according to whether the second protease inhibitor was ritonavir or nelfinavir. Saquinavir concentrations in the groups receiving the combination of delavirdine plus adefovir dipivoxil were reduced by approximately 50% compared with those receiving delavirdine. Delavirdine concentrations were reduced by approximately 50%, in the delavirdine plus adefovir dipivoxil arms compared with the delavirdine arms. CONCLUSIONS: Saquinavir concentrations were significantly lower in the arms containing the combination of delavirdine and adefovir dipivoxil compared with the arms containing delavirdine. Delavirdine concentrations were significantly lower when coadministered with adefovir dipivoxil. These drug-drug interactions were not expected, the mechanism(s) is (are) not clear, and additional studies are warranted. This study illustrates the need to understand more fully the pharmacokinetic characteristics of complex combination antiretroviral regimens prior to use in patient management.

Adenine↗
PubMed2000

Randomized study of saquinavir with ritonavir or nelfinavir together with delavirdine, adefovir, or both in human immunodeficiency virus-infected adults with virologic failure on indinavir: AIDS Clinical Trials Group Study 359.

This study compared antiretroviral activity among 6 "salvage" therapy regimens. The study was a prospective, randomized, 2x3 factorial, multicenter study of the AIDS Clinical Trials Group. The study enrolled 277 human immunodeficiency virus (HIV)-infected patients naive to nonnucleoside analogues who had taken indinavir >6 months. The patients had 2000-200,000 HIV RNA copies/mL. Patients received saquinavir with ritonavir or nelfinavir together with delavirdine and/or adefovir and were followed for safety and antiretroviral response between baseline and week 16. At week 16, 30% (77/254) of patients had </=500 HIV RNA copies/mL. Virologic response did not differ significantly between pooled ritonavir and nelfinavir groups (28% vs. 33%; P=.50) or between pooled delavirdine and delavirdine/adefovir groups (40% vs. 33%; P=.42). Pooled delavirdine groups had a greater virologic response rate than did adefovir groups (40% vs. 18%; P=.002). Overall, one-third of patients who experienced virologic failure on an indinavir-containing regimen suppressed virus load levels while they were taking a new salvage regimen.

Adenine↗
PubMed2000

Detection of Kaposi's sarcoma-associated herpesvirus in oral and genital secretions of Zimbabwean women.

Kaposi's sarcoma-associated herpesvirus (KSHV) in oral and genital secretions of women may be involved in horizontal and vertical transmission in endemic regions. Nested polymerase chain reaction assays were used to detect KSHV DNA sequences in one-third of oral, vaginal, and cervical specimens and in 42% of peripheral blood mononuclear cell (PBMC) specimens collected from 41 women infected with human immunodeficiency virus type 1 who had Kaposi's sarcoma (KS). KSHV DNA was not detected in specimens from 100 women without KS, 9 of whom were seropositive for KSHV. A positive association was observed between KSHV DNA detection in oral and genital mucosa, neither of which was associated with KSHV DNA detection in PBMC. These data suggest that KSHV replicates in preferred anatomic sites at levels independent of PBMC viremia. Detection of genital-tract KSHV only among relatively immunosuppressed women may provide an explanation for infrequent perinatal transmission of KSHV.

AIDS-Related Opportunistic Infections↗
PubMed2000

A phase II trial of nerve growth factor for sensory neuropathy associated with HIV infection. AIDS Clinical Trials Group Team 291.

OBJECTIVE: To evaluate the safety and efficacy of recombinant human nerve growth factor (rhNGF) in HIV-associated sensory neuropathy (SN) within a multicenter, placebo-controlled, randomized trial (ACTG 291). BACKGROUND: SN affects 30% of individuals with AIDS, is worsened by neurotoxic antiretrovirals, and its treatment is often ineffective. NGF is trophic for small sensory neurons and stimulates the regeneration of damaged nerve fibers. METHODS: A total of 270 patients with HIV-associated SN were randomized to receive placebo, 0.1 microg/kg rhNGF, or 0.3 microg/kg rhNGF by double-blinded subcutaneous injection twice weekly for 18 weeks. The primary outcome was change in self-reported neuropathic pain intensity (Gracely Pain Scale). Secondary outcomes included an assessment of global improvement in neuropathy by patients and investigators, neurologic examination, use of prescription analgesics, and quantitative sensory testing. In a subset, epidermal nerve fiber densities were determined in punch skin biopsies. RESULTS: Both doses of NGF produced significant improvements in average and maximum daily pain compared with placebo. Positive treatment effects were also observed for global pain assessments (p = 0.001) and for pin sensitivity (p = 0.019). No treatment differences were found with respect to mood, analgesic use, or epidermal nerve fiber densities. Injection site pain was the most frequent adverse event, and resulted in unblinding in 39% of subjects. Severe transient myalgic pain occurred in eight patients, usually from accidental overdosing. There were no changes in HIV RNA levels or other laboratory indices. CONCLUSIONS: We found a positive effect of recombinant human nerve growth factor on neuropathic pain and pin sensitivity in HIV-associated sensory neuropathy. rhNGF was safe and well tolerated, but injection site pain was frequent.

Adult↗
PubMed2000

The relation between baseline HIV drug resistance and response to antiretroviral therapy: re-analysis of retrospective and prospective studies using a standardized data analysis plan.

To assess the relation between resistance to antiretroviral drugs for treatment of HIV-1 infection and virological response to therapy, results from 12 different studies were re-analysed according to a standard data analysis plan. These studies included nine clinical trials and three observational cohorts. The primary end-point in our analyses was virological failure by week 24. Baseline factors that were investigated as predictors of virological failure were plasma HIV-1 RNA, the number and type of new antiretroviral drugs in the regimen, and viral susceptibility to the drugs in the regimen, determined by genotyping or phenotyping methods. These analyses confirmed the importance of both genotypic and phenotypic drug resistance as predictors of virological failure, whether these factors were analysed separately or adjusted for other baseline confounding factors. In most of the re-analysed studies, the odds of virological failure were reduced by about twofold for each additional drug in the regimen to which the patient's virus was sensitive by genotyping methods, and by about two- to threefold for each additional drug that was sensitive by phenotyping.

Anti-HIV Agents↗
PubMed1999

HIV-1 genotypic resistance patterns predict response to saquinavir-ritonavir therapy in patients in whom previous protease inhibitor therapy had failed.

BACKGROUND: Tests for resistance to HIV drugs are available for clinical use; however, their predictive value has not been fully assessed. OBJECTIVES: To determine HIV-1 genotypic predictors of a virologic response to saquinavir-ritonavir therapy in patients in whom at least one previous protease inhibitor-containing regimen had failed and to compare the predictive value of baseline genotype with that of standard clinical evaluation. DESIGN: Retrospective clinical cohort study. SETTING: University-based HIV clinic. PATIENTS: 54 HIV-1-infected adults treated with saquinavir-ritonavir who had experienced virologic failure while receiving a protease inhibitor-containing regimen for at least 3 months. MEASUREMENTS: HIV-1 reverse transcriptase and protease gene sequences, CD4 cell counts, clinical characteristics, detailed antiretroviral treatment history, and plasma HIV-1 RNA levels at baseline and at three follow-up time points (median, 4, 12, and 26 weeks). Virologic failure was defined as a plasma HIV RNA level greater than 1000 copies/mL. RESULTS: In 22 patients (41%), a plasma HIV-1 RNA level less than 500 copies/mL was achieved by week 12; in 15 patients (28%), this response was maintained through week 26. Clinical characteristics predicting a poorer response included a diagnosis of AIDS, lower CD4 cell count, and higher plasma HIV RNA level (P<0.03). Number of previous nucleoside reverse transcriptase inhibitors, previous protease inhibitor therapy, and duration of previous protease inhibitor therapy were predictors of poorer response (P<0.01). Multivariate regression models revealed that protease mutations present at the initiation of saquinavir-ritonavir therapy were the strongest predictors of virologic response. A model of clinical features explained up to 45% of the variation in virologic outcomes by week 12, whereas the explained variance was 71% when genotypic predictors were included. CONCLUSIONS: In patients in whom protease inhibitor-containing antiretroviral therapy fails, HIV-1 genotype is predictive of virologic response to subsequent therapy. This predictive capacity adds to that of standard clinical evaluation.

Adult↗
PubMed1999

Comparison of gynecologic history and laboratory results in HIV-positive women with CD4+ lymphocyte counts between 200 and 500 cells/microl and below 100 cells/microl.

OBJECTIVE: To assess rates of sexual activity, contraceptive use, genital infections and dysplasia, and other gynecologic symptoms among well-characterized populations of HIV-seropositive women enrolled in two Adult AIDS Clinical Trials Group (AACTG) randomized studies. METHODS: Gynecologic data were collected using standardized interview and examination forms from women enrolled in two protocols: ACTG 175, an antiretroviral trial (CD4+ lymphocyte counts 200-500 cells/microl) and ACTG 196, a Mycobacterium avium complex prophylaxis trial (CD4+ counts < or =100 cells/microl). RESULTS: Women enrolled in the two studies were similar in age, race, weight, and history of illicit or injection drug use, but women in ACTG 196 (n = 67) had lower median CD4+ counts (median, 35 cells/microl; range, 0-135 cells/microl versus median, 356 cells/microl; range, 131-620 cells/microl; p < .0005), were less likely to be antiretroviral naive (6% versus 38%; p < .0005), and were more likely to have a Karnofsky score <80 (28% versus 5%; p < .0001) than women in ACTG 175 (n = 185) at baseline. Recent changes in menstrual cycle were not different between groups. Women enrolled in ACTG 196 were less likely to be sexually active (40% versus 61%; p < .005), but both groups reported high levels of contraceptive use. Papanicolaou smear results in ACTG 196 and ACTG 175 respectively, were: normal, 38% and 50%, atypia, 24% and 39%, low-grade squamous intraepithelial lesions (SIL), 27% and 10%, and high-grade SIL, 11% and 0.7% (p < .001). CONCLUSIONS: Gynecologic complications are common among HIV-seropositive women with CD4+ lymphocyte counts < 500 cells/microl and are more common and severe among those with more advanced immunosuppression.

Adult↗
PubMed1999

Prevalence and incidence of herpes simplex virus type 2 infection among male Zimbabwean factory workers.

Stored sera from a cohort of 2397 male factory workers in Harare, Zimbabwe, were screened for herpes simplex virus type 2 (HSV-2)-specific antibodies, to estimate the prevalence and incidence of genital herpes infection and to assess the relation between HSV-2 and human immunodeficiency virus (HIV) acquisition. The prevalence of HSV-2 at enrollment was 39.8%. Correlates of HSV-2 seropositivity were HIV seropositivity, marital status, history of sexually transmitted disease (STD), older age, and higher income. The incidence of HSV-2 seroconversion during follow-up was 6.2/100 person-years. Correlates of HSV-2 seroconversion were enrollment while HIV-positive or seroconversion during follow-up, reported genital ulcer, history of STD, and number of sex partners. No evidence was found that HSV-2 infection was more likely to precede HIV or vice versa. HSV-2 and HIV seropositivity are strong markers for high-risk sexual behavior. Improved interventions targeted to populations in which the incidence of either viral infection is high are needed.

Adolescent↗
PubMed1998

Characterizing patterns of drug-taking behavior with a multiple drug regimen in an AIDS clinical trial.

OBJECTIVE: To characterize drug-taking behavior using continuous electronic monitoring in an AIDS clinical trial. SETTING: This was a substudy of AIDS Clinical Trials Group (ACTG) protocol 175, a phase II/III study of dideoxynucleoside monotherapy versus combination therapy in asymptomatic HIV-positive subjects. Participants were required to comply with regimens containing zidovudine, zalcitabine and didanosine, or matching placebos; the total daily pill count was 16. DESIGN: For participants at two ACTG 175 sites, electronic devices were used to monitor drug-taking behavior of all study medications over a period of approximately 90 days. MEASUREMENTS: Four indices of drug-taking behavior were calculated and their distributions and relationship to the prescribed regimen were examined. RESULTS: Data from 41 subjects were analyzed. Of the prescribed doses of zidovudine, zalcitabine and didanosine, 88, 84 and 82%, respectively, were taken. Of these, 55, 66 and 79%, respectively, were taken at the prescribed dosing frequency. The median percentage of days on which participants failed to take any of the doses was 2-5%. There was a trend towards lower adherence in the combination therapy arms compared with those assigned to receive monotherapy. In this analysis, older patients demonstrated better adherence, although patient characteristics, in general, were poorly predictive of adherence. CONCLUSION: Drug-taking behavior for all three active study medications differed from that prescribed. One result of this erratic adherence was that study participants sustained little antiretroviral effect during more than 25% of the monitoring period.

Acquired Immunodeficiency Syndrome↗
PubMed1998

The extent of non-adherence in a large AIDS clinical trial using plasma dideoxynucleoside concentrations as a marker.

OBJECTIVES: To assess adherence to study medications in an AIDS clinical trial, to evaluate whether study participants adhered to only one component of a multidrug regimen ('differential adherence'), and to determine whether there was evidence of non-uniform adherence to study medications among treatment groups. SETTING: This was a substudy of AIDS Clinical Trials Group protocol 175, a large, double-blind, randomized study of monotherapy versus combination dideoxynucleoside therapy. Participants were required to adhere to a complex regimen of zidovudine, zalcitabine and didanosine, or their matching placebos. DESIGN: Between October 1992 and January 1994, study sites were selected at random, and a 1-week period was designated during which study participants attending routine clinic visits provided a blood sample and dosing history. Participants were not informed of the purpose of the substudy. MEASUREMENTS: Adherence was assessed using plasma drug concentrations and defined by the presence of detectable drug in a plasma sample obtained within a specified analysis window. RESULTS: Of 722 plasma samples analyzed, approximately 75% contained detectable concentrations of the assigned drugs and 5-14.5% contained no detectable drugs. Approximately 7 and 13% of samples from participants assigned to monotherapy arms contained non-prescribed dideoxynucleosides, and 14 and 19% assigned to combination therapies contained only one drug. CONCLUSIONS: Various non-adherence behaviors were observed, including patterns of underdosing and taking non-prescribed drugs. Non-adherence was moderate but uniform amongst the treatment groups and may have contributed to a marginal reduction in the power of the primary intent-to-treat analysis to detect differences in efficacy amongst the assigned treatments.

Acquired Immunodeficiency Syndrome↗
PubMed1998

Geographic and demographic differences in the frequency of human cytomegalovirus gB genotypes 1-4 in immunocompromised patients.

To test the hypothesis that human cytomegalovirus (CMV) gB genotype may differ with geographic origin or patient demographics, CMV DNA was amplified for gB typing from immunocompromised patients in Italy and Africa and compared with previously reported frequencies in California. Increased gB2 frequency occurred in Italian homosexual AIDS patients, as compared with both Italian heterosexual injection drug users with AIDS and heterosexual Zimbabwe AIDS patients. Occurrence of gB3 in Italy was higher in injection drug users than in homosexual AIDS patients. The incidence of gB4 was higher overall in the Italian as compared with the California patients. Therefore geographic and demographic differences in patients affect gB distribution and should be considered before associations of gB genotypes and virulence are made.

Acquired Immunodeficiency Syndrome↗