Biomedical subjects

Paulo F Barroso

Publications and source records attributed to Paulo F Barroso.

5 recordsLinked to original sources

PubMed2006

Viral load and CD4 count dynamics after HIV-1 seroconversion in homosexual and bisexual men in Rio de Janeiro, Brazil.

PURPOSE: Reliable predictors of HIV disease progression are scarce in developing countries, where most HIV infections occur. We describe early virologic and immunologic events among men who have sex with men in Rio de Janeiro, Brazil. METHODS: Seroconverters from 2 high-risk cohorts were followed for up to 36 months with periodic laboratory evaluations, plasma viral load, and CD4 count assessments. Viral load and CD4 count mean trajectories were computed. For the modeled viral loads, mean and median values were 24,480 (4.36 log10) and 19,720 (4.29 log10) copies/mL (range 14,880-58,090), respectively. Median CD4 count was 373 cells/microL (range 260-508). Overall variation on viral loads ranged from 4.3 to 5.2 log10 copies/mL with a visible increase in the viral load starting at approximately 600 days (n = 12) after estimated time of seroconversion. The initial period of HIV infection was characterized by an increase in CD4 count (n = 29) followed by a steep decline starting at approximately 200 days (508 cells, 95% CI: 425 to 569). A gradual decrease was observed in the median CD4 count thereafter, reaching 281 (95% CI: 100 to 466) at 1000 days after the estimated date of seroconversion. CONCLUSIONS: Although viral load dynamics resembled those observed in developed countries, CD4 counts seem to decline at a faster rate than in the Multicenter AIDS Cohort Study (MACS) cohort. Clinical and survival data are needed to assess the impact of interventions, such as antiretroviral therapy, on the clinical course of HIV infection in Brazil.

Adult↗

PubMed2006

Limited penetration of lopinavir and ritonavir in the genital tract of men infected with HIV-1 in Brazil.

The concentrations of lopinavir and ritonavir in seminal and blood plasma and the seminal human immunodeficiency virus (HIV) viral load were quantified by HPLC and the Nuclisens assay, respectively, in a cross-sectional study of 16 HIV-1-infected Brazilian men under stable treatment with a lopinavir/ritonavir containing antiretroviral regimen. Semen and blood samples were collected on 2 occasions: at 6 to 60 minutes before ("trough"), and 5 to 6 hours after ("peak") ingestion of regular doses of lopinavir/ritonavir. Median seminal lopinavir levels were 120.6 ng/mL (range, <20-1481.8 ng/mL) and 233.1 ng/mL (range, 48.4-1133.4 ng/mL) at trough and peak points, respectively. The corresponding values for ritonavir were 9.2 ng/mL (range, <5-47 ng/mL) and 17.1 ng/mL (range, 6.6-66.7 ng/mL). The median concentrations of lopinavir and ritonavir in semen were, respectively, 1.9% to 3% and 3.7% to 4.4% of those measured in blood plasma samples collected within 30 minutes. HIV-1 viral load was detectable in the semen of 2 and in the blood of 6 of 16 patients. These results may have implications for drug-resistant HIV-1 evolution and transmission.

Biological Availability↗

PubMed2003

Adherence to antiretroviral therapy and persistence of HIV RNA in semen.

CONTEXT: Long-term adherence to antiretrovirals is critical for sustained virologic response to HIV therapy in blood. Although antiretroviral therapy (ART) reduces HIV seminal shedding, little is known about the relationship between adherence to ART and HIV suppression in semen. OBJECTIVE: To determine predictors of seminal HIV RNA suppression after 6 months of ART. DESIGN: Prospective observational cohort of 93 HIV-infected subjects before and after introduction of ART. Seminal HIV RNA was measured at baseline and 1, 2, 3, and 6 months after the introduction of therapy. Adherence to therapy was measured by self-report. SETTING: A large academic HIV reference center in Rio de Janeiro, Brazil. MAIN OUTCOME MEASURE: Detectable HIV RNA in semen. RESULTS: In a multivariate logistic model with undetectable seminal HIV RNA after 6 months of therapy as the outcome variable, adjusting for baseline seminal viral load, both being adherent to therapy (OR = 11.8, < 0.01) and using triple-drug ART (OR = 6.48, = 0.04) were independently associated with seminal HIV RNA suppression. CONCLUSIONS: Inability to adhere to therapy was strongly associated with persistent shedding of HIV RNA in semen. Measures to improve adherence are urgently needed to reduce the sexual spread of potentially drug-resistant HIV among subjects using antiretrovirals.

Adult↗

PubMed2003

Accidental infection of laboratory worker with vaccinia virus.

We report the accidental needlestick inoculation of a laboratory worker with vaccinia virus. Although the patient had previously been vaccinated against smallpox, severe lesions appeared on the fingers. Western blot and polymerase chain reaction-restriction fragment length polymorphism were used to analyze the virus recovered from the lesions. The vaccinia virus-specific immunoglobulin G levels were measured by enzyme-linked immunosorbent assay. Our study supports the need for vaccination for laboratory workers that routinely handle orthopoxvirus.

Adult↗

PubMed2002

Mixture models for quantitative HIV RNA data.

Clinical investigators are increasing their use of quantitative determinations of HIV viral load in their study populations. The distributions of these measures may be highly skewed, left-censored, and with an extra spike below the detection limit of the assay. We recommended use of a mixture model in this situation, with two sets of explanatory covariates. We extend this model to incorporate multiple measures across time, and to employ shared parameters as a way of increasing model efficiency and parsimony. Data from a cohort of HIV-infected men are used to illustrate these features, and simulations are performed to assess the utility of shared parameters.

Brazil↗