Voltage-dependent and voltage-independent blockade of acetyicholine receptors by local anesthetics in E!ectrophorus electroplaques

SUMMARY KOBLIN, DONAL

Capturing the Molecular Mechanism of Anesthetic Action by Simulation Methods

Significant computational efforts have been focused toward exposing the molecular mechanisms of anesthesia in recent years. In the past decade, this has been aided considerably by a momentous increase in the number of high-resolution structures of ion channels, which are putative targets for the anesthetic agents, as well as advancements in high-performance computing technologies. In this review, typical simulation methods to investigate the behavior of model membranes and membrane-protein systems are briefly reviewed, and related computational studies are surveyed. Both lipid- and protein-mediated mechanisms of anesthetic action are scrutinized, focusing on the behavior of ion channels in the latter case

Use of a High Resolution Melting (HRM) Assay to Compare Gag, Pol, and Env Diversity in Adults with Different Stages of HIV Infection

Cross-sectional assessment of HIV incidence relies on laboratory methods to discriminate between recent and non-recent HIV infection. Because HIV diversifies over time in infected individuals, HIV diversity may serve as a biomarker for assessing HIV incidence. We used a high resolution melting (HRM) diversity assay to compare HIV diversity in adults with different stages of HIV infection. This assay provides a single numeric HRM score that reflects the level of genetic diversity of HIV in a sample from an infected individual.HIV diversity was measured in 203 adults: 20 with acute HIV infection (RNA positive, antibody negative), 116 with recent HIV infection (tested a median of 189 days after a previous negative HIV test, range 14-540 days), and 67 with non-recent HIV infection (HIV infected >2 years). HRM scores were generated for two regions in gag, one region in pol, and three regions in env.Median HRM scores were higher in non-recent infection than in recent infection for all six regions tested. In multivariate models, higher HRM scores in three of the six regions were independently associated with non-recent HIV infection.The HRM diversity assay provides a simple, scalable method for measuring HIV diversity. HRM scores, which reflect the genetic diversity in a viral population, may be useful biomarkers for evaluation of HIV incidence, particularly if multiple regions of the HIV genome are examined

Performance of a Limiting-Antigen Avidity Enzyme Immunoassay for Cross-Sectional Estimation of HIV Incidence in the United States

Background: A limiting antigen avidity enzyme immunoassay (HIV-1 LAg-Avidity assay) was recently developed for cross-sectional HIV incidence estimation. We evaluated the performance of the LAg-Avidity assay alone and in multi-assay algorithms (MAAs) that included other biomarkers. Methods and Findings: Performance of testing algorithms was evaluated using 2,282 samples from individuals in the United States collected 1 month to >8 years after HIV seroconversion. The capacity of selected testing algorithms to accurately estimate incidence was evaluated in three longitudinal cohorts. When used in a single-assay format, the LAg-Avidity assay classified some individuals infected >5 years as assay positive and failed to provide reliable incidence estimates in cohorts that included individuals with long-term infections. We evaluated >500,000 testing algorithms, that included the LAg-Avidity assay alone and MAAs with other biomarkers (BED capture immunoassay [BED-CEIA], BioRad-Avidity assay, HIV viral load, CD4 cell count), varying the assays and assay cutoffs. We identified an optimized 2-assay MAA that included the LAg-Avidity and BioRad-Avidity assays, and an optimized 4-assay MAA that included those assays, as well as HIV viral load and CD4 cell count. The two optimized MAAs classified all 845 samples from individuals infected >5 years as MAA negative and estimated incidence within a year of sample collection. These two MAAs produced incidence estimates that were consistent with those from longitudinal follow-up of cohorts. A comparison of the laboratory assay costs of the MAAs was also performed, and we found that the costs associated with the optimal two assay MAA were substantially less than with the four assay MAA. Conclusions: The LAg-Avidity assay did not perform well in a single-assay format, regardless of the assay cutoff. MAAs that include the LAg-Avidity and BioRad-Avidity assays, with or without viral load and CD4 cell count, provide accurate incidence estimates

Analysis of HIV Diversity in HIV-Infected Black Men Who Have Sex with Men (HPTN 061)

Background: HIV populations often diversify in response to selective pressures, such as the immune response and antiretroviral drug use. We analyzed HIV diversity in Black men who have sex with men who were enrolled in the HIV Prevention Trials Network 061 study. Methods: A high resolution melting (HRM) diversity assay was used to measure diversity in six regions of the HIV genome: two in gag, one in pol, and three in env. HIV diversity was analyzed for 146 men who were HIV infected at study enrollment, including three with acute infection and 13 with recent infection (identified using a multi-assay algorithm), and for 21 men who seroconverted during the study. HIV diversification was analyzed in a paired analysis for 62 HIV-infected men using plasma samples from the enrollment and 12-month (end of study) visits. Results: Men with acute or recent infection at enrollment and seroconverters had lower median HRM scores (lower HIV diversity) than men with non-recent infection in all six regions analyzed. In univariate analyses, younger age, higher CD4 cell count, and HIV drug resistance were associated with lower median HRM scores in multiple regions; ARV drug detection was marginally associated with lower diversity in the pol region. In multivariate analysis, acute or recent infection (all six regions) and HIV drug resistance (both gag regions) were associated with lower median HRM scores. Diversification in the pol region over 12 months was greater for men with acute or recent infection, higher CD4 cell count, and lower HIV viral load at study enrollment. Conclusions: HIV diversity was significantly associated with duration of HIV infection, and lower gag diversity was observed in men who had HIV drug resistance. HIV pol diversification was more pronounced in men with acute or recent infection, higher CD4 cell count, and lower HIV viral load

1970s and 'Patient 0' HIV-1 genomes illuminate early HIV/AIDS history in North America.

The emergence of HIV-1 group M subtype B in North American men who have sex with men was a key turning point in the HIV/AIDS pandemic. Phylogenetic studies have suggested cryptic subtype B circulation in the United States (US) throughout the 1970s and an even older presence in the Caribbean. However, these temporal and geographical inferences, based upon partial HIV-1 genomes that postdate the recognition of AIDS in 1981, remain contentious and the earliest movements of the virus within the US are unknown. We serologically screened >2,000 1970s serum samples and developed a highly sensitive approach for recovering viral RNA from degraded archival samples. Here, we report eight coding-complete genomes from US serum samples from 1978-1979-eight of the nine oldest HIV-1 group M genomes to date. This early, full-genome 'snapshot' reveals that the US HIV-1 epidemic exhibited extensive genetic diversity in the 1970s but also provides strong evidence for its emergence from a pre-existing Caribbean epidemic. Bayesian phylogenetic analyses estimate the jump to the US at around 1970 and place the ancestral US virus in New York City with 0.99 posterior probability support, strongly suggesting this was the crucial hub of early US HIV/AIDS diversification. Logistic growth coalescent models reveal epidemic doubling times of 0.86 and 1.12 years for the US and Caribbean, respectively, suggesting rapid early expansion in each location. Comparisons with more recent data reveal many of these insights to be unattainable without archival, full-genome sequences. We also recovered the HIV-1 genome from the individual known as 'Patient 0' (ref. 5) and found neither biological nor historical evidence that he was the primary case in the US or for subtype B as a whole. We discuss the genesis and persistence of this belief in the light of these evolutionary insights.This work was supported by NIH/NIAID R01AI084691 and the David and Lucile Packard Foundation (M.W.); the Wellcome Trust (080651), the University of Oxford’s Clarendon Fund, the Economic and Social Research Council (PTA-026-27-2838), and a J. Armand Bombardier Internationalist Fellowship (R.A.M.); the Research Fund KU Leuven (Onderzoeksfonds KU Leuven, Program Financing no. PF/10/018) and the ‘Fonds voor Wetenschappelijk Onderzoek Vlaanderen’ (FWO) (G066215N) (P.L); and NSF DMS 1264153, NIH R01 HG006139 and NIH R01 AI107034 (M.A.S.).This is the author accepted manuscript. The final version is available from Nature Publishing Group via https://doi.org/10.1038/nature1982

Formative Assessment of ARM-U: A Modular Intervention for Decreasing Risk Behaviors Among HIV-Positive and HIV-Negative Methamphetamine-Using MSM

BACKGROUND: Methamphetamine is a major contributor to HIV transmission among men who have sex with men (MSM). Recent studies show that up to one-third of methamphetamine-using MSM (MUMSM) inject the drug. We developed a behavioral intervention for MUMSM to decrease unprotected anal intercourse and increase awareness of parenteral HIV transmission risk. This 6-session (3 in-person, 3 by telephone) modular intervention was designed to be tailored to participants' HIV (+/-) and injection drug user ([IDU] yes/no) status. We present results of formative research used to evaluate the content and to assess feasibility and acceptability of this individual-level HIV risk-reduction intervention. SETTING: HIV research clinic in a high MSM and methamphetamine prevalence neighborhood. PROJECT: Avoiding Risks from Methamphetamine-Use (ARM-U) is a brief toolbox intervention that allows counselors to select modules that suit a client's individual risk profile and intervention needs employing motivational interviewing and cognitive behavioral theory. We evaluated the format and content of the intervention through focus groups and pre-testing of the entire intervention using volunteers from the target population stratified into four groups (HIV+/IDU, HIV-/IDU, HIV+/non-IDU, HIV-/non-IDU). Four individuals in each stratum were recruited to undergo the intervention and complete a satisfaction survey at the end of each in-person session. RESULTS: In total, 25 MUMSM attended one of five focus groups. Participants thought all proposed intervention topics were important and could aid in reducing sexual risk behaviors among MUMSM. However, the neurocognitive effects of methamphetamine were reported to be a barrier to practicing safer sex, condom use negotiation or HIV status disclosure. Fifteen (94%) of 16 participants completed all 6 sessions and the satisfaction survey. On average, participants felt the intervention was useful for MUMSM, made them contemplate and move toward behavior change, and would recommend the program to their peers. LESSONS LEARNED: Based on our formative research, we revised the ARM-U intervention to emphasize pre-planning to avoid combining methamphetamine use and sex or develop strategies to avoid sex risk following methamphetamine use. We also increased emphasis on referrals for care and other requested services. Future efficacy trials are needed to evaluate the intervention's ability to reduce HIV-associated risk behaviors

Methamphetamine Use, Transmission Risk Behavior and Internet Use Among HIV-Infected Patients in Medical Care, San Francisco, 2008

Methamphetamine use is associated with adverse health outcomes and HIV incidence. Few studies have assessed methamphetamine use, sexual behavior and Internet use among HIV-infected patients. Surveys were administered to a sample of HIV-infected patients seeking medical care in a San Francisco county hospital and university-based clinic. In 2008, 35% of homosexual participants, 26% of heterosexual participants and 11% of female participants reported methamphetamine use in the past year. Of participants, 29% reported using the Internet to find sex partners; Internet-users versus non-Internet-users reported a higher median number of sex partners in 6 months (4 vs. 1), were more likely to report unprotected sex (32 vs. 10%), and higher rates of methamphetamine use in the past 12 months (48 vs. 24%). Given the association among methamphetamine use, increased sex partners and Internet use, the Internet may present a new and effective medium for interventions to reduce methamphetamine-associated sexual risk behavior