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Find video protocols related to scientific articles indexed in Pubmed.
The absolute lymphocyte count accurately estimates CD4 counts in HIV-infected adults with virologic suppression and immune reconstitution.
J Int AIDS Soc
PUBLISHED: 01-01-2014
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The clinical value of monitoring CD4 counts in immune reconstituted, virologically suppressed HIV-infected patients is limited. We investigated if absolute lymphocyte counts (ALC) from an automated blood counting machine could accurately estimate CD4 counts.
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Trends of CD4 cell count levels at the initiation of antiretroviral therapy over time and factors associated with late initiation of antiretroviral therapy among Asian HIV-positive patients.
J Int AIDS Soc
PUBLISHED: 01-01-2014
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Although antiretroviral therapy (ART) has been rapidly scaled up in Asia, most HIV-positive patients in the region still present with late-stage HIV disease. We aimed to determine trends of pre-ART CD4 levels over time in Asian HIV-positive patients and to determine factors associated with late ART initiation.
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Draft Genome Sequence of a Multidrug-Resistant New Delhi Metallo-?-Lactamase-1 (NDM-1)-Producing Escherichia coli Isolate Obtained in Singapore.
Genome Announc
PUBLISHED: 12-21-2013
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We report the draft genome sequence of a New Delhi metallo-?-lactamase-1 (NDM-1)-positive Escherichia coli isolate obtained from a surgical patient. The assembled data indicate the presence of 3 multidrug resistance plasmids, 1 of which shares 100% identity with an NDM-1 plasmid isolated previously from a nearby hospital, suggesting possible local transmission.
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Genetic Signatures of HIV-1 Envelope Mediated Bystander Apoptosis.
J. Biol. Chem.
PUBLISHED: 11-21-2013
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The Envelope (Env) glycoprotein of HIV is an important determinant of viral pathogenesis. Several lines of evidence support the role of HIV-1 Env in inducing bystander apoptosis that may be a contributing factor in CD4+ T cell loss. However, most of the studies testing this phenomenon have been conducted with lab adapted HIV-1 isolates. This raises the question whether primary Envs derived from HIV infected patients are capable of inducing bystander apoptosis and whether specific Env signatures are associated with this phenomenon. We developed a high throughput assay to determine the bystander apoptosis inducing activity of a panel of primary Envs. We tested 38 different Envs for bystander apoptosis, virion infectivity, neutralizing antibody sensitivity, Putative N-linked Glycosylation Sites (PNGS) along with a comprehensive sequence analysis to determine if specific sequence signatures within the viral Env are associated with bystander apoptosis. Our studies show that primary Envs vary considerably in their bystander apoptosis inducing potential, a phenomenon that correlates inversely with PNGS and positively with virion infectivity. By use of a novel phylogenetic analysis that avoids subtype bias coupled with structural considerations, we found specific residues like R476 and N425 that were associated with differences in bystander apoptosis induction. A specific role of these residues was also confirmed experimentally. These data demonstrate for the first time the potential of primary R5 Envs to mediate bystander apoptosis in CD4+ T cells. Furthermore, we identify specific genetic signatures within the Env that may be associated with bystander apoptosis inducing phenotype.
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Challenges of respondent driven sampling to assess sexual behaviour and estimate the prevalence of human immunodeficiency virus (HIV) and syphilis in men who have sex with men (MSM) in Singapore.
Ann. Acad. Med. Singap.
PUBLISHED: 08-17-2013
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There is a lack of representative samples to provide reliable and accurate seroprevalence of sexually transmitted infections (STIs) and human immunodeficiency virus (HIV) as well as behavioural information among men who have sex with men (MSM) in Singapore. We used respondent driven sampling (RDS) to recruit MSM. Participants completed a survey used by Asian Internet MSM Sex Survey (AIMSS) and were tested for HIV and syphilis. We compared the characteristics of the RDS participants with STI diagnosis against those who did not have any STI diagnosis in the past 6 months. We compared RDS participants with AIMSS participants. Of 72 MSM recruited, 1 was positive for HIV (1.3%) and 4 (5.5%) tested positive for syphilis. Median age was 30 years and majority was Chinese (69.4%). RDS participants who had any STI diagnosis reported to have more use of recreational drugs (P = 0.006), and lower condom use (P = 0.054). Comparing RDS participants (n = 72) with the AIMSS participants (n = 2075), RDS respondents had ?1 male partner in the past 6 months (P = 0.003), more casual sex partners (P = 0.012) and more STI symptoms (P = 0.019). There was no difference in terms of HIV testing and recreational drug use. The HIV and syphilis seroprevalence rates from our study are similar to previous reports conducted in high-risk MSM. In contrast to other settings, RDS did not work well among MSM in Singapore. The public health implications of our study highlight the challenges in obtaining data for HIV surveillance in assessing prevalence and risk behaviours among MSM.
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HIV Type 1 Polymerase Gene Polymorphisms Are Associated With Phenotypic Differences in Replication Capacity and Disease Progression.
J. Infect. Dis.
PUBLISHED: 08-06-2013
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Background.?Determinants of intersubtype differences in human immunodeficiency virus type 1 (HIV-1) clinical disease progression remain unknown. Methods.?HIV-1 subtype was independently determined for 5 separate genomic regions in 396 HIV-1 seroconverters from Rakai, Uganda, using a multiregion hybridization assay. Replication capacities (RC) in samples from a subset of 145 of these subjects were determined. HIV-1 genomic regions and pol RC were examined for association with disease progression. Amino acid polymorphisms were examined for association with pol RC. Results.?In multivariate analyses, the hazard for progression to the composite end point (defined as a CD4(+) T-cell count <250 cells/mm(3), antiretroviral therapy initiation, or death) among patients with subtype D pol infection was 2.4 times the hazard for those infected with subtype A pol infection (P = .001). Compared with subtype A pol (the reference group), the hazard for progression to the composite end point for subtype D pol infection with a pol RC >67% (ie, the median pol RC) was significantly greater (HR, 4.6; 95% confidence interval [CI], 1.9-11.0; P = .001), whereas the hazard for progression to the composite end point for subtype D pol infection with a pol RC ?67% was not significantly different (HR, 2.2; 95% CI, 1.0-4.9; P = .051). Amino acid substitutions at protease positions 62 and 64 and at reverse transcriptase position 272 were associated with significant differences in pol RC. Conclusions.?HIV-1 pol gene intersubtype and RC differences are associated with disease progression and may be influenced by amino acid polymorphisms.
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Identification of conserved motifs in the Westnile virus envelope essential for particle secretion.
BMC Microbiol.
PUBLISHED: 05-09-2013
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Enveloped viruses utilize cellular membranes to bud from infected cells. The process of virion assembly and budding is often facilitated by the presence of certain conserved motifs within viral proteins in conjunction with cellular factors. We hence examined the West Nile Virus (WNV) Envelope protein for the presence of any such motifs and their functional characterization.
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High prevalence of CXCR4 usage among treatment-naive CRF01_AE and CRF51_01B-infected HIV-1 subjects in Singapore.
BMC Infect. Dis.
PUBLISHED: 02-08-2013
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Recent studies suggest HIV-1 inter-subtype differences in co-receptor usage. We examined the correlation between HIV-1 subtype and co-receptor usage among treatment-naïve HIV-1 subjects in Singapore. Additionally, we investigated whether the subtype co-receptor association was influenced by stage of infection.
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Phylodynamic Profile of HIV-1 Subtype B, CRF01_AE and the Recently Emerging CRF51_01B among Men Who Have Sex with Men (MSM) in Singapore.
PLoS ONE
PUBLISHED: 01-01-2013
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HIV-1 subtype B and CRF01_AE are the predominant infecting subtypes among men who have sex with men (MSM) in Singapore. The genetic history, population dynamics and pattern of transmission networks of these genotypes remain largely unknown. We delineated the phylodynamic profiles of HIV-1 subtype B, CRF01_AE and the recently characterized CRF51_01B strains circulating among the MSM population in Singapore. A total of 105 (49.5%) newly-diagnosed treatment-naïve MSM were recruited between February 2008 and August 2009. Phylogenetic reconstructions of the protease gene (HXB2: 2239 - 2629), gp120 (HXB2: 6942 - 7577) and gp41 (HXB2: 7803 - 8276) of the env gene uncovered five monophyletic transmission networks (two each within subtype B and CRF01_AE and one within CRF51_01B lineages) of different sizes (involving 3 - 23 MSM subjects, supported by posterior probability measure of 1.0). Bayesian coalescent analysis estimated that the emergence and dissemination of multiple sub-epidemic networks occurred between 1995 and 2005, driven largely by subtype B and later followed by CRF01_AE. Exponential increase in effective population size for both subtype B and CRF01_AE occurred between 2002 to 2007 and 2005 to 2007, respectively. Genealogical estimates suggested that the novel CRF51_01B lineages were probably generated through series of recombination events involving CRF01_AE and multiple subtype B ancestors. Our study provides the first insight on the phylodynamic profiles of HIV-1 subtype B, CRF01_AE and CRF51_01B viral strains circulating among MSM in Singapore.
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Identification of new CRF51_01B in Singapore using full genome analysis of three HIV type 1 isolates.
AIDS Res. Hum. Retroviruses
PUBLISHED: 09-23-2011
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A recent HIV-1 molecular epidemiology survey in Singapore identified a novel CRF01_AE/B recombinant form, which accounted for 13 (11.9%) of 109 patient samples. Peripheral blood mononuclear cell DNA from three of these 13 patients was used to generate near full-length sequences to characterize the novel CRF01_AE/B recombinant form. The three isolates had a recombinant structure composed of CRF01_AE and subtype B, and shared identical breakpoints. As the three patients were not epidemiologically linked, this recombinant form has been designated CRF51_01B. Identification of the novel recombinant forms indicates ongoing active HIV-1 transmission in Singapore.
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Molecular epidemiology of HIV type 1 in Singapore and identification of novel CRF01_AE/B recombinant forms.
AIDS Res. Hum. Retroviruses
PUBLISHED: 02-14-2011
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To investigate HIV-1 molecular epidemiology in Singapore, we sequenced portions of three regions of the HIV-1 genome (protease HXB2: 2163 to 2620, gp120 HXB2: 6904 to 7628, and gp41 HXB2: 7817 to 8264) from 212 plasma samples collected between February 2008 and August 2009. From these samples, 109 (51.4%) generated interpretable data in all regions. Sixty-one (56.0%) were identified as CRF01_AE, 26 (23.9%) as subtype B and 14 (12.8%) as possible novel recombinant forms. The main novel recombinant pattern, detected in 13 sequences, had subtype B in protease and gp41 and CRF01_AE in gp120. There was intermixing of subtypes within transmission risk groups. However, 85% of subjects infected with the novel recombinant forms self-identified as men who have sex with men or bisexuals compared with only 41% of individuals infected with CRF01_AE and 62% infected with subtype B (p = 0.001).
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Increased rate of CD4+ T-cell decline and faster time to antiretroviral therapy in HIV-1 subtype CRF01_AE infected seroconverters in Singapore.
PLoS ONE
PUBLISHED: 01-27-2011
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It remains controversial as to whether HIV-1 subtypes influence disease progression. Singapore offers a unique opportunity to address this issue due to the presence of co-circulating subtypes. We compared subtype CRF01_AE and non-CRF01_AE infected patients, with regards to estimated annual rate of CD4+ T-cell loss and time from estimated data of seroconversion (EDS) to antiretroviral therapy (ART).
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Older age at initial presentation to human immunodeficiency virus (HIV) care and treatment at the Communicable Disease Centre (CDC) in Singapore, 2006 to 2011.
Ann. Acad. Med. Singap.
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The incidence of newly diagnosed older patients diagnosed with human immunodeficiency virus (HIV) has increased worldwide in recent years. In this study, we compared the demographics and clinical presentation of younger and older patients in our HIV sentinel cohort.
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Causes of death in hospitalised HIV-infected patients at a National Referral Centre in Singapore: a retrospective review from 2008 to 2010.
Ann. Acad. Med. Singap.
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Highly active antiretroviral therapy (HAART) has improved outcomes for individuals infected with human immunodeficiency virus (HIV). This study describes the causes of death in hospitalised HIV-positive patients from 2008 to 2010 in Tan Tock Seng Hospital, the national referral centre for HIV management in Singapore.
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Clinical evaluation of an in-house human immunodeficiency virus (HIV) genotyping assay for the detection of drug resistance mutations in HIV-1 infected patients in Singapore.
Ann. Acad. Med. Singap.
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Human immunodeficiency virus type 1 (HIV-1) genotyping resistance test (GRT) is essential for monitoring HIV-1 drug resistance mutations (DRMs). High cost and HIV-1 genetic variability are challenges to assay availability in Singapore. An in-house Sanger sequencing-based GRT method was developed at the Communicable Disease Centre (CDC), Singapores HIV national treatment reference centre for both subtype B and non-subtype B HIV-1.
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Accuracy and user-acceptability of HIV self-testing using an oral fluid-based HIV rapid test.
PLoS ONE
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The United States FDA approved an over-the-counter HIV self-test, to facilitate increased HIV testing and earlier linkage to care. We assessed the accuracy of self-testing by untrained participants compared to healthcare worker (HCW) testing, participants ability to interpret sample results and user-acceptability of self-tests in Singapore.
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Opt-out of voluntary HIV testing: a Singapore hospitals experience.
PLoS ONE
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Since 2008, the Singapore Ministry of Health (MOH) has expanded HIV testing by increasing anonymous HIV test sites, as well as issuing a directive to hospitals to offer routine voluntary opt out inpatient HIV testing. We reviewed this program implemented at the end of 2008 at Tan Tock Seng Hospital (TTSH), the second largest acute care general hospital in Singapore.
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What is Visualize?

JoVE Visualize is a tool created to match the last 5 years of PubMed publications to methods in JoVE's video library.

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We use abstracts found on PubMed and match them to JoVE videos to create a list of 10 to 30 related methods videos.

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In developing our video relationships, we compare around 5 million PubMed articles to our library of over 4,500 methods videos. In some cases the language used in the PubMed abstracts makes matching that content to a JoVE video difficult. In other cases, there happens not to be any content in our video library that is relevant to the topic of a given abstract. In these cases, our algorithms are trying their best to display videos with relevant content, which can sometimes result in matched videos with only a slight relation.