127 research outputs found
Nonlinear Mixed-Effects Models for HIV Viral Load Trajectories Before and After Antiretroviral Therapy Interruption, Incorporating Left Censoring
No full textCharacterizing features of the viral rebound trajectories and identifying host, virological, and immunological factors that are predictive of the viral rebound trajectories are central to HIV cure research. In this paper, we investigate if key features of HIV viral decay and CD4 trajectories during antiretroviral therapy (ART) are associated with characteristics of HIV viral rebound following ART interruption. Nonlinear mixed effect (NLME) models are used to model viral load trajectories before and following ART interruption, incorporating left censoring due to lower detection limits of viral load assays. A stochastic approximation EM (SAEM) algorithm is used for parameter estimation and inference. To circumvent the computational intensity associated with maximizing the joint likelihood, we propose an easy-to-implement threestep method. We evaluate the performance of this method through simulation studies and apply it to data from the Zurich Primary HIV Infection Study. We find that some key features of viral load during ART (e.g., viral decay rate) are significantly associated with important characteristics of viral rebound following ART interruption (e.g., viral set point)
Impact of HIV-1 reverse transcriptase polymorphism F214L on virological response to thymidine analogue-based regimens in antiretroviral therapy (ART)-naive and ART-experienced patients
No full textBackground. A negative association between the polymorphism F214L and type 1 thymidine analogue ( TA) mutations (TAMs) has been observed. However, the virological response to TAs according to the detection of F214L has not been evaluated. Methods. We studied 590 patients from EuroSIDA who started TA therapy for the first time as part of potent combination antiretroviral therapy (cART) and who were tested for genotypic resistance within the past 6 months. End points were median reduction in the week 24 viral load and time to virological failure (2 consecutive VL measurements > 400 copies/mL after at least 6 months of the TA-containing cART). Results. In ART-naive patients, the prevalence of F214L was 17%. By 48 months after starting TA-based cART, the proportion of patients who experienced virological failure was 16% in patients with 214L and 36% in those with 214F (p = .03). In a multivariable Cox regression model, the relative hazard of virological failure for patients with 214L compared with those with 214F was 0.22 (95% confidence interval, 0.07-0.72). In ART-experienced patients, results were similar, and larger differences in virological response associated with the detection of 214L versus F were observed in patients with M41L/T215Y and mixed TAM profiles detected before the initiation of cART. Conclusions. This study provides evidence that the detection of polymorphism F214L is associated with a favorable virological response to TA-based cART
Anticholinergic medication use in elderly people living with HIV and self-reported neurocognitive impairment: a prospective cohort study
No full textBACKGROUND
Anticholinergic (ACH) medications have been associated with neurocognitive impairment, particularly in the elderly. This study determined prospectively the prevalence of prescribed ACH medications and their association with self-reported neurocognitive impairment (SRNI) in elderly people living with HIV (PLWH) of the Swiss HIV Cohort Study (SHCS).
METHODS
A literature review was performed to identify ACH medications, which were scored 0 to 3 (higher score indicating more ACH burden). Prescriptions were reviewed in July 2019 for all SHCS participants ≥65 years old to assess the prevalence of ACH medications. Association between ACH burden and neurocognitive impairment was evaluated using the SHCS SRNI questions addressing memory loss, attention difficulties and slowing in reasoning.
RESULTS
One thousand and nineteen PLWH (82% male) with a median age of 70 (IQR = 67-74) years were included. Most participants were on ART (99%). The average number of non-HIV drugs was 5.1 ± 3.6, representing a polypharmacy prevalence of 50%. Two hundred participants (20%) were on ≥1 ACH medication, with an average ACH score of 1.7 ± 1.3. SRNI, adjusted for age, sex, CD4, nadir CD4, viral load, efavirenz use and polypharmacy, was associated with depression (OR = 4.60; 95% CI = 2.62-8.09) and a trend was observed with being on ≥1 ACH medication (OR = 1.69; 95% CI = 0.97-2.95). In a subgroup analysis of participants without depression (n = 911), SRNI was associated with the use of ≥1 ACH medication (OR = 2.51; 95% CI = 1.31-4.80).
CONCLUSIONS
ACH medication use is common in elderly PLWH and contributes to SRNI. The effect of ACH medications on neurocognitive impairment warrants further evaluation using neurocognitive tests
How effectively can HIV phylogenies be used to measure heritability?
No full textBackground and objectives: The severity of HIV-1 infection, measured by set-point viral load (SPVL), is highly variable between individuals. Its heritability between infections quantifies the control the pathogen genotype has over disease severity. Heritability estimates vary widely between studies, but differences in methods make comparison difficult. Phylogenetic comparative analysis offers measures of phylogenetic signal, but it is unclear how to interpret them in terms of the fraction of variance in SPVL controlled by the virus genotype.
Methodology: We present computational methods which link statistics summarizing phylogenetic signal to heritability, h2 in order to test for and quantify it. We re-analyse data from Switzerland and Uganda, and apply it to new data from the Netherlands. We systematically compare established and new (e.g. phylogenetic pairs, PP) phylogenetic signal statistics.
Results: Heritability estimates varied by method and dataset. Several methods were consistently able to detect simulated heritability above Graphic, but none below. Pagel’s λ was the most robust and sensitive. The PP method found no heritability in the Netherlands data, whereas Pagel’s λ found significant heritability only in a narrow subdivision (P = 0.038). Heritability was estimated at h2 = 0.52 (95% confidence interval 0.00–0.63).
Conclusions and implications: This standardized measure, h2, allows comparability of heritability between cohorts. We confirm high heritability in Swiss data, but neither in Ugandan data nor in the Netherlands, where it is barely significant or undetectable. Existing phylogenetic methods are ill-suited for detecting heritability below Graphic, which may nonetheless be biologically important
2010 Guidelines for Antiretroviral Treatment of HIV From the International AIDS Society-USA Panel-Reply
No full textMinority K65R variants and early failure of antiretroviral therapy in HIV-1-infected Eritrean Immigrant
No full textANALYSIS OF THE B-TYPE BAND OF THE ANTI ROTAMER OF 1,2-DIFLUOROETHANE AT
No full text1. P. Huber-Walchli and Hs. H. Gunthard, Spectrochim. Acta 37A, 285 (1981). 2. H. Takeo, C. Matsumura and Y. Morino, J. Chem. Phys. 84, 4205 (1986). 3. P. Huber-Walchli and Hs. H. Gunthard, Chem. Phys. Lett. 30, 347 (1975). 4. J. R. Durig, J. Liu. T. S. Little and V. F. Kalasinsky, J. Chem. Phys. 96, 8224 (1992).Author Institution: Oberlin College, Oberlin, OH 44074; Justus-Liebig-Universität, D-35392 Giessen, GermanyThe abundant form of 1,2-difluoroethane is the gauche rotamer for which a complete microwave-based structure is No structure exists, however, for the non-polar anti rotamer. Although the IR spectrum of 1,2-difluoroethane is dominated by bands of the gauche rotamer, low resolution IR spectra revealed two promising bands for high resolution investigation of the anti rotamer, a C-type band at and a B-type band at At high resolution the C-type band had some assignable series, but gauche rotamer lines overwhelmed the center of the band and the P branch. In contrast, the B-type band due to , the antisymmetric CF bending mode, was essentially free of gauche lines and largely unperturbed. The B-type band of this near-prolate top with was recorded at resolution on a Bruker IFS 120 instrument. From the analysis of this band 1086 ground-state combination-differences gave, in . For , fitting the upper state gave ^{13}C_{2}d_{4}$ isotopomers have been recorded and are being analyzed. From the full set of rotational constants we expect to derive a complete structure for the anti rotamer of 1,2-difluoroethane
Cellular Viral Rebound after Cessation of Potent Antiretroviral Therapy Predicted by Levels of Multiply Spliced HIV‐1 RNA Encodingnef
No full textTo characterize newly arising replication of human immunodeficiency virus (HIV) type 1 in vivo at the cellular level, distinct viral RNA species in peripheral blood mononuclear cells (PBMCs) from HIV-1-infected patients were monitored during 2 weeks of structured treatment interruption (STI). HIV-1 RNA encoding tat/rev and PBMC-associated virions were almost completely depleted during antiretroviral therapy and emerged simultaneously after 2 weeks of STI, thus specifically reflecting productive viral infection at the cellular level. The magnitude of these correlates of reappearing cellular viral replication was predicted by during-therapy levels of nef transcripts in PBMCs. Significant rebound of plasma viremia, representing the progeny of a broader range of anatomical compartments, preceded and predicted productive infection in PBMCs. Thus, cellular viral rebound in PBMCs likely was primed before STI by the expression of nef in HIV-1-infected PBMCs that lacked virion production and was subsequently triggered by the plasma viremia that preceded the recurrence of productively infected PBMC
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