Biomedical subjects

D Vlahov

Publications and source records attributed to D Vlahov.

At least 109 records · Page 6Linked to original sources

PubMed1999

Class II HLA alleles and hepatitis B virus persistence in African Americans.

Persistence of hepatitis B virus (HBV) infection is likely due to the interplay of the virus and host immune response. Given its critical role in antigen presentation, allelic differences in the HLA complex may affect HBV persistence. In a prospectively followed African American cohort, molecular class I and class II HLA typing was done on 31 subjects with persistent HBV infection and 60 controls who cleared the infection. HBV persistence was significantly associated with two class II alleles, DQA1 *0501 (odds ratio [OR], 2.6; P=.05) and DQB1 *0301 (OR, 3.9; P=.01), the two-locus haplotype consisting of these same two alleles (OR, 3; P=. 005) and the three-locus haplotype, DQA1 *0501, DQB1 *0301, and DRB1 *1102 (OR, 10.7; P=.01). In addition, HBV persistence was associated with class II allelic homozygosity. Several class I associations with persistence were also noted but were not statistically significant after correction for multiple comparisons. These results underscore the importance of the class II-mediated immune response in recovery from HBV infection.

Adult↗

PubMed1999

Comparison between a whole blood interferon-gamma release assay and tuberculin skin testing for the detection of tuberculosis infection among patients at risk for tuberculosis exposure.

A new test that measures interferon-gamma (IFN-gamma) release in whole blood following stimulation with tuberculin has the potential to detect tuberculosis infection using a single blood draw. The IFN-gamma release assay was compared with the standard tuberculin skin test (TST) among 467 intravenous drug users at risk for tuberculosis in urban Baltimore. Among 300 human immunodeficiency virus (HIV)-seronegative patients, the IFN-gamma release assay was positive in 177 (59%), whereas the TST was positive in 71 (24%), for a percent agreement of 59% (kappa=26%). Among 167 HIV-seropositive subjects, the IFN-gamma release assay identified 32 reactors (19%); the TST identified 16 reactors (9.6%), for a percent agreement of 82% (kappa=28%). The IFN-gamma release assay detected more reactors than did the TST, but its agreement with TST was weak. As the TST is an imperfect standard, further evaluation of the IFN-gamma release assay among uninfected persons and persons with culture-confirmed tuberculosis will be useful.

Evaluation Studies as Topic↗

PubMed1999

Sex differences in longitudinal human immunodeficiency virus type 1 RNA levels among seroconverters.

Cross-sectional studies have demonstrated lower plasma human immunodeficiency virus type 1 (HIV-1) RNA virus levels (VLs) in women than in men, but it is unknown whether this sex difference is present at the time of seroconversion and throughout the course of infection. A nested case-control study was performed among HIV-1 seroconverters within a cohort of injection drug users. Plasma VL was determined longitudinally among both rapid progressors to AIDS (24 patients) and nonprogressors (47 controls). The initial median VL among female patients (n=10) was 14,918 copies/mL, compared with 148,354 copies/mL among male patients (n=14; P=.001); median plasma VL also tended to be lower among female (n=10) than among male controls (n=37; 11,917 vs. 61,311 copies/mL; P=.08). VL increased more rapidly over time in women than in men and subsequently converged in patients and controls, respectively. Understanding the mechanisms responsible for the sex difference in VL may provide insight into HIV-1 pathogenesis.

Acquired Immunodeficiency Syndrome↗

PubMed1999

Longitudinal human immunodeficiency virus type 1 load in the italian seroconversion study: correlates and temporal trends of virus load.

A prospective study of 149 human immunodeficiency virus type 1 (HIV-1) seroconverters was conducted to describe trends and correlates of HIV-1 load after seroconversion and over time. HIV-1 load was quantified from frozen sera by reverse transcriptase-polymerase chain reaction. High early virus load was associated with lower CD4 cell counts and male sex but not with age at seroconversion or injection drug use. Early virus load predicted progression to clinical AIDS and AIDS/<200 CD4 cells/microL. Virus load exhibited a decline of 52% by 18 months after seroconversion then increased 23% annually (95% confidence interval, 13%-33%). Men and those developing AIDS during follow-up had higher virus loads over the course of disease. Persons who developed AIDS had a steeper virus load slope than those who were AIDS-free (P=.01). In long-term follow-up, virus load exhibited a gradual and sustained increase over time. Virus load and annual increase are strong predictors of disease progression.

Acquired Immunodeficiency Syndrome↗

PubMed1999

The effect of drug-injection behavior on genetic evolution of HIV-1.

The effect of injection-drug use on human immunodeficiency virus type 1 (HIV-1) env genetic evolution was examined in 15 seroconverting injection-drug users followed up for 4 years. After adjustment for non-drug-related independent variables significantly associated with genetic diversity (time since seroconversion and progressor status), injection frequency was positively and highly significantly associated with HIV-1 env genetic diversity (P=.003). The mutation rate in those who had injected at least once a day during the previous 6 months was estimated to be 62% greater than the rate in those who had not injected at all. If the positive effect of drug-injection frequency on env genetic diversity extends to the HIV-1 pol gene, the risk of emergence of resistance to antiretroviral drugs may be enhanced by increased drug-injection frequency, especially under the selection pressure of antiretroviral therapy.

Adult↗

PubMed1999

The impact of multifocused interventions on sharps injury rates at an acute-care hospital.

OBJECTIVE: To determine the impact of a multifocused interventional program on sharps injury rates. DESIGN: Sharps injury data were collected prospectively over a 9-year period (1990-1998). Pre- and postinterventional rates were compared after the implementation of sharps injury prevention interventions, which consisted of administrative, work-practice, and engineering controls (ie, the introduction of an anti-needlestick intravenous catheter and a new sharps disposal system). SETTING: Sharps injury data were collected from healthcare workers employed by a mid-sized, acute-care community hospital. RESULTS: Preinterventional annual sharps injury incidence rates decreased significantly from 82 sharps injuries/1,000 worked full-time-equivalent employees (WFTE) to 24 sharps injuries/1,000 WFTE employees postintervention (P<.0001), representing a 70% decline in incidence rate overall. Over the course of the study, the incidence rate for sharps injuries related to intravenous lines declined by 93%, hollow-bore needlesticks decreased by 75%, and non-hollow-bore injuries decreased by 25%. CONCLUSION: The implementation of a multifocused interventional program led to a significant and sustained decrease in the overall rate of sharps injuries in hospital-based healthcare workers.

Emergency Medical Services↗

PubMed1999

Self-reported bacterial infections among women with or at risk for human immunodeficiency virus infection.

Bacterial infections are a major cause of morbidity and mortality in persons with human immunodeficiency virus (HIV) infection, particularly women. We performed a cross-sectional analysis of a history of bacterial infections among 1,310 women with or at risk for HIV infection. HIV-seropositive women were significantly more likely than seronegative women to report recent and lifetime histories of bacterial infection, even after history of injection drug use since 1977 was adjusted for; this included recent pneumonia (odds ratio [OR], 3.2; 95% confidence interval [CI], 1.5-6.6), sinusitis (OR, 1.4; 95% CI, 1.0-2.0), and urinary tract infection (OR, 1.5; 95% CI, 1.1-2.1). Compared with HIV-negative women, women with CD4 cell counts of <200 were about eight times more likely to report recent pneumonia (OR, 7.8; 95% CI, 3.4-17.7); those with CD4 cell counts of 200-500 were almost three times more likely to do so (OR, 2.6; CI, 1.2-5.7). Logistic regression analysis revealed that only CD4 cell category and a recent history of smoking had a significant relationship to self-reported pneumonia.

AIDS-Related Opportunistic Infections↗

PubMed1999

Compliance with universal precautions in correctional health care facilities.

There were three main objectives of this cross-sectional study of Maryland State correctional health care workers. The first was to evaluate compliance with work practices designed to minimize exposure to blood and body fluids; the second, to identify correlates of compliance with universal precautions (UPs); and the third was to determine the relationship, if any, between compliance and exposures. Of 216 responding health care workers, 34% reported overall compliance across all 15 items on a compliance scale. Rates for specific items were particularly low for use of certain types of personal protective equipment, such as protective eyewear (53.5%), face mask (47.2%) and protective clothing (33.9%). Compliance rates were highest for glove use (93.2%) waste disposal (89.8%), and sharps disposal (80.8%). Compliance rates were generally not associated with demographic factors, except for age; younger workers were more likely to be compliant with safe work practices than were older workers (P < 0.05). Compliance was positively associated with several work-related variables, including perceived safety climate (i.e., management's commitment to infection control and the overall safety program) and job satisfaction, and was found to be inversely associated with security-related work constraints, job/task factors, adverse working conditions, workplace discrimination, and perceived work stress. Bloodborne exposures were not uncommon; 13.8% of all respondents had at least one bloodborne exposure within the previous 6 months, and compliance was inversely related to blood and body fluid exposures. This study identified several potentially modifiable correlates of compliance, including factors unique to the correctional setting. Infection-control interventional strategies specifically tailored to these health care workers may therefore be most effective in reducing the risk of bloodborne exposures.

Adult↗

PubMed1999

Access to antiretroviral treatment among French HIV infected injection drug users: the influence of continued drug use. MANIF 2000 Study Group.

STUDY OBJECTIVE: To determine the influence of continued drug use and its perception by prescribing physicians on access to antiretroviral treatment among French HIV infected injection drug users (IDUs). DESIGN: Cross sectional including enrollment data (October 1995-1996) of the cohort study MANIF 2000. Access to treatment is compared in three groups: former IDUs (n = 68) and active IDUs whether or not this behaviour remains undetected (n = 38) or detected (n = 17) by physicians. SETTING: Hospital departments for specialist AIDS care in south eastern France and inner suburbs of Paris. PATIENTS: All enrolled patients with CD4+ cell counts < 400 with detailed clinical history, access to treatment, risk behaviours, and past drug use as reported by both physicians and patients (n = 123). MAIN RESULTS: A minority (43.9%) already received an antiretroviral treatment. Active IDUs had worst socioeconomic and psychological conditions but only those detected by physicians were considered as poorly compliant. Logistic regression showed that, with respect to ex-IDUs and independently of clinical stage, active IDUs, whether or not they were perceived as such by physicians, were threefold more likely not to receive antiretroviral treatment. CONCLUSIONS: Even among French HIV infected IDUs who have regular access to AIDS specialised hospital care, continued drug use reduced the likelihood of being prescribed antiretroviral treatment. To reduce delays in access to new treatments, specific efforts must be devoted towards both AIDS specialists and IDU patients to overcome current stereotypes of non-compliance associated with continued injection.

Adolescent↗

PubMed1999

Differing risk factors for cerebral palsy in the presence of mental retardation and epilepsy.

Whether the combined diagnosis of cerebral palsy with mental retardation or with mental retardation and epilepsy reflects more severe manifestations of the spectrum of cerebral palsy, or whether these conditions reflect overlapping outcomes related to different exposure, remains an open question. At two centers, in Rome and Conegliano, Italy, 51 children with combined cerebral palsy, mental retardation, and epilepsy, 31 children with both cerebral palsy and mental retardation, and 48 with cerebral palsy alone were identified and examined, and their mothers interviewed. The triple diagnosis group was significantly more likely than the other two groups to have a history of neonatal convulsions and a history of epilepsy in first-degree relatives, but less likely to have a mother's age at delivery greater than 33 years, a birthweight less than 1500 g, or gestational age less than 32 weeks. The dual diagnosis group was more likely than the other two groups to have maternal education of less than 8 years. These data suggest the possibility of different etiopathogenetic pathways for various presentations of cerebral palsy.

Adolescent↗

PubMed1999

Syringe vending machines for injection drug users: an experiment in Marseille, France.

OBJECTIVES: This study evaluated the usefulness of vending machines in providing injection drug users with access to sterile syringes in Marseille, France. METHODS: Self-administered questionnaires were offered to 485 injection drug users obtaining syringes from 32 pharmacies, 4 needle exchange programs, and 3 vending machines. RESULTS: Of the 343 respondents (response rate = 70.7%), 21.3% used the vending machines as their primary source of syringes. Primary users of vending machines were more likely than primary users of other sources to be younger than 30 years, to report no history of drug maintenance treatment, and to report no sharing of needles or injection paraphernalia. CONCLUSIONS: Vending machines may be an appropriate strategy for providing access to syringes for younger injection drug users, who have typically avoided needle exchange programs and pharmacies.

Adolescent↗

PubMed1999

Pre-AIDS mortality and morbidity among injection drug users in Amsterdam and Baltimore: an ecological comparison.

Mortality and morbidity between injecting drug users in Amsterdam (n = 624) and Baltimore (n = 2,185) are compared to generate a hypothesis about the role of different health care systems and drug user policies (universal care and harm reduction versus episodic care and criminalization, respectively). Overdose/suicide mortality was twofold higher in Amsterdam; no sufficient explanation was found. Other independent "risk factors" for overdose/suicide mortality were recent injecting, polydrug use, and HIV-seropositivity (especially with CD4 count < 200/mm3). High dose methadone maintenance was associated with lower mortality. Incidence of hospitalizations and emergency room visits was substantially lower in Amsterdam, suggesting that higher accessibility to primary care in Amsterdam lowers (inpatient) hospital visits and presumably societal costs.

Adult↗

PubMed1999

Serologic evidence of rickettsialpox (Rickettsia akari) infection among intravenous drug users in inner-city Baltimore, Maryland.

We tested single serum samples from 631 intravenous (i.v.) drug users from inner-city Baltimore, Maryland for serologic evidence of exposure to spotted fever group rickettsiae. A total of 102 (16%) individuals had titers > or = 64 to Rickettsia rickettsii by an indirect immunofluorescence assay. Confirmation that infection was caused by R. akari was obtained by cross-adsorption studies on a subset of serum samples that consistently resulted in higher titers to R. akari than to R. rickettsii. Current i.v. drug use, increased frequency of injection, and shooting gallery use were significant risk factors for presence of group-specific antibodies reactive with R. rickettsii. There was a significant inverse association with the presence of antibodies reactive to R. rickettsii and antibodies reactive to the human immunodeficiency virus. This study suggests that i.v. drug users are at an increased risk for R. akari infections. Clinicians should be aware of rickettsialpox, as well as other zoonotic diseases of the urban environment, when treating i.v. drug users for any acute febrile illness of undetermined etiology.

Antibodies, Bacterial↗

PubMed1999

The effect of immunodeficiency on cutaneous delayed-type hypersensitivity testing in HIV-infected women without anergy: implications for tuberculin testing. HER Study Group. HIV Epidemiology Research.

SETTING: A collaborative study in four urban medical centers in the United States. OBJECTIVE: To determine the effect of human immunodeficiency virus (HIV) infection and immunodeficiency on delayed type hypersensitivity (DTH) responses and the implications for interpretation of tuberculin reactions in non-anergic women with or at risk for HIV infection. DESIGN: Demographic and behavioral information, HIV antibody testing, CD4+ lymphocyte counts, and cutaneous responses to DTH testing with mumps, Candida, tetanus toxoid, and tuberculin (purified protein derivative-PPD) antigens were obtained in 1184 women. RESULTS: Reactions to one or more of the four antigens occurred in 436 HIV-seropositive and 356 high-risk seronegative women. Among non-anergic women, HIV-seropositives were less likely (P < or = 0.05) to react to mumps (62% vs 81%), tetanus (72% vs 84%), and PPD (13% vs 19%). Induration in HIV-seropositive reactors was associated with CD4+ cell level for mumps (P = 0.004) and tetanus (P < 0.001), but not for Candida or PPD. HIV-seropositive reactors with CD4+ cell counts >500/mm3 did not have significantly smaller reactions than HIV-seronegatives for any antigen tested. PPD sizes were similar among HIV-seropositive reactors with CD4+ cell counts >500/mm3 (12.4 +/- 7.4 mm) and HIV-seronegative reactors (12.0 +/- 8.3 mm); induration > or =10 mm was seen in 16/173 (9.2%) seropositive women with CD4+ cell counts >500/mm3 and 41/356 (11.5%) seronegative women, respectively (P = 0.5). CONCLUSION: Among HIV-infected women able to react to a DTH antigen, induration in response to that antigen was relatively intact at CD4+ counts >500/mm3. This suggests that degree of immunodeficiency should be considered when interpreting PPD reactions in HIV-infected persons.

Adolescent↗

PubMed1999

Idiopathic chronic fatigue and chronic fatigue syndrome: a comparison of two case-definitions.

The aim of the study was to compare the signs and symptoms of individuals meeting two different definitions of chronic fatigue syndrome (CFS). Ninety-four patients fitting the eligibility criteria for idiopathic fatigue were enrolled into the study. Of the 94 patients, 48 met the 1988 definition of CFS, 20 the 1994 (but not the 1988) definition of CFS, and 26 met neither definition. The 1994 defined cases were more likely than 1988 defined cases, and non-syndromal individuals to be male, married, and high school educated. The 1994 cases were less likely than 1988 cases to present acute onset, self reported sore throat, mild fever lymphadenopathy, pharyngitis. In conclusion, the 1994 criteria increased the number of patients classified as CFS; however, those who fit only the 1994 criteria were less likely to have an acute symptomatic onset and signs and symptoms suggestive of an infectious process.

Adolescent↗

PubMed1998

Genetic acceleration of AIDS progression by a promoter variant of CCR5.

The CCR5 gene encodes a cell surface chemokine receptor molecule that serves as the principal coreceptor, with CD4, for macrophage-tropic (R5) strains of human immunodeficiency virus-type 1 (HIV-1). Genetic association analysis of five cohorts of people with acquired immunodeficiency syndrome (AIDS) revealed that infected individuals homozygous for a multisite haplotype of the CCR5 regulatory region containing the promoter allele, CCR5P1, progress to AIDS more rapidly than those with other CCR5 promoter genotypes, particularly in the early years after infection. Composite genetic epidemiologic analyses of genotypes bearing CCR5P1, CCR5-Delta32, CCR2-64I, and SDF1-3'A affirmed distinct regulatory influences for each gene on AIDS progression. An estimated 10 to 17 percent of patients who develop AIDS within 3.5 years of HIV-1 infection do so because they are homozygous for CCR5P1/P1, and 7 to 13 percent of all people carry this susceptible genotype. The cumulative and interactive influence of these AIDS restriction genes illustrates the multigenic nature of host factors limiting AIDS disease progression.

Acquired Immunodeficiency Syndrome↗

PubMed1998

Molecular and geographic patterns of tuberculosis transmission after 15 years of directly observed therapy.

CONTEXT: Recent studies suggest that one third of tuberculosis cases in urban areas result from recent transmission. Improved tuberculosis control measures such as uniform implementation of directly observed therapy might reduce the proportion of cases resulting from recent transmission. OBJECTIVE: To determine patterns of tuberculosis transmission in Baltimore, Md, after 15 years of community-based directly observed therapy. DESIGN: A 30-month (January 1994-June 1996), prospective, city-wide study of all cases of tuberculosis using traditional contact investigations, geographic information systems data, and molecular epidemiologic comparison of Mycobacterium tuberculosis isolates with 2 DNA probes. PATIENTS: One hundred eighty-two patients with culture-positive tuberculosis. MAIN OUTCOME MEASURES: Proportion of disease defined as recently transmitted based on epidemiologic linkage by traditional contact tracing and molecular linkage by DNA fingerprint analysis of isolates; geographic foci of transmission based on linkage of residences by geographic information systems data. RESULTS: Of the 182 patients who had isolates of M tuberculosis available, 84 (46%) showed molecular clustering with 58 (32%) defined as being recently transmitted. Only 20 (24%) of 84 cases with clustered DNA fingerprints had epidemiologic evidence of recent contact. Geographic analysis showed significant spatial aggregation of the 20 clustered cases with epidemiologic links (P<.001), occurring in areas of low socioeconomic status and high drug use. The 64 cases with clustered DNA fingerprints but without epidemiologic links shared common risk factors and demographic features with the 20 clustered patients who did have epidemiologic links. CONCLUSIONS: Recently transmitted tuberculosis accounts for a high proportion of tuberculosis cases in Baltimore. Recently transmitted cases occur in geographically distinct areas of Baltimore, and location-based control efforts may be more effective than contact tracing for the early identification of cases.

Adult↗

PubMed1998

Sex differences in HIV-1 viral load and progression to AIDS.

BACKGROUND: Plasma HIV-1 RNA measurements are used for initiation of antiretroviral treatments. Whether the viral-load association with prognosis is similar in women and men is unknown. METHODS: We studied 812 specimens from 650 injection-drug users (IDUs) participating in a continuous observational study of patients based in a community clinic. HIV-1 load was measured by branched-chain DNA on samples from 527 IDUs from the baseline visit, and by reverse-transcriptase PCR and quantitative microculture on samples from 285 IDUs at a follow-up visit 3 years later. FNDINGS: Women had lower median viral-load measurements than men by branched-chain DNA (3365 vs 8907 copies/mL; p=0.001), reverse-transcriptase PCR (45416 vs 93130 copies/mL; p=0.02), and quantitative microculture (5 vs 8 infectious units per million peripheral blood mononuclear cells; p=0.015). This association remained even after adjustment for CD4 cell count, race, and drug use within the previous 6 months. Time to AIDS was statistically similar for men and women in a univariate proportional-hazards model and in a model adjusting for CD4 cell count. Proportional-hazards models showed that women with the same viral load as men had a 1.6-fold higher risk of AIDS (95% CI 1.10-2.32); or, equivalently, that women with half the viral load of men had a similar time to AIDS as men. INTERPRETATION: Although a biological mechanism remains unclear, these data suggest that current recommendations for HIV-1 viral-load thresholds to initiate antiretroviral therapy should be revised downwards for women.

Acquired Immunodeficiency Syndrome↗