244 research outputs found

    Incidence of Human Herpesvirus 8 (HHV-8) infection among HIV-uninfected individuals at high risk for sexually transmitted infections

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    <p>Abstract</p> <p>Background</p> <p>The occurrence of, and risk factors for, HHV-8 infection have yet to be definitively determined, particularly among heterosexual individuals with at-risk behavior for sexually transmitted infections (STI). The objective of this study was to estimate the incidence and determinants of HHV-8 infection among HIV-uninfected individuals repeatedly attending an urban STI clinic.</p> <p>Methods</p> <p>Sera from consecutive HIV-uninfected individuals repeatedly tested for HIV-1 antibodies were additionally tested for HHV-8 antibodies using an immunofluorescence assay. To identify determinants of HHV-8 infection, a nested case-control study and multivariate logistic regression analysis were performed.</p> <p>Results</p> <p>Sera from 456 HIV-uninfected individuals (224 multiple-partner heterosexuals and 232 men who have sex with men (MSM]) were identified for inclusion in the study. The HHV-8 seroprevalence at enrollment was 9.4% (21/224; 95% C.I.: 6.0–14.2%) among heterosexuals with multiple partners and 22.0% (51/232; 95% C.I.: 16.9–28.0%) among MSM. Among the 203 multiple-partner heterosexuals and 181 MSM who were initially HHV-8-negative, 17 (IR = 3.0/100 p-y, 95% C.I.: 1.9 – 4.8) and 21 (IR = 3.3/100 p-y, 95% C.I:.2.1 – 5.1) seroconversions occurred, respectively. HHV-8 seroconversion tended to be associated with a high number of sexual partners during the follow-up among MSM (> 10 partners: AOR = 3.32 95% CI:0.89–12.46) and among the multiple-partner heterosexuals (> 10 partner; AOR = 3.46, 95% CI:0.42–28.2). Moreover, among MSM, HHV-8 seroconversion tended to be associated with STI (AOR = 1.80 95%CI: 0.52–7.96).</p> <p>During the study period the HIV-1 incidence was lower than that of HHV-8 among both groups (0.89/100 p-y among MSM and 0.95/100 p-y among multiple-partner heterosexuals).</p> <p>Conclusion</p> <p>The large difference between the incidence of HHV-8 and the incidence of HIV-1 and other STIs may suggest that the circulation of HHV-8 is sustained by practices other than classical at-risk sexual behavior.</p

    Kaposi sarcoma incidence in the Swiss HIV Cohort Study before and after highly active antiretroviral therapy

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    Between 1984 and 2006, 12 959 people with HIV/AIDS (PWHA) in the Swiss HIV Cohort Study contributed a total of 73 412 person-years (py) of follow-up, 35 551 of which derived from PWHA treated with highly active antiretroviral therapy (HAART). Five hundred and ninety-seven incident Kaposi sarcoma (KS) cases were identified of whom 52 were among HAART users. Cox regression was used to estimate hazard ratios (HR) and corresponding 95% confidence intervals (CI). Kaposi sarcoma incidence fell abruptly in 1996–1998 to reach a plateau at 1.4 per 1000 py afterwards. Men having sex with men and birth in Africa or the Middle East were associated with KS in both non-users and users of HAART but the risk pattern by CD4 cell count differed. Only very low CD4 cell count (<50 cells μl−1) at enrolment or at HAART initiation were significantly associated with KS among HAART users. The HR for KS declined steeply in the first months after HAART initiation and continued to be low 7–10 years afterwards (HR, 0.06; 95% CI, 0.02–0.17). Thirty-three out of 52 (63.5%) KS cases among HAART users arose among PWHA who had stopped treatment or used HAART for less than 6 months

    Crucial Role for BAFF-BAFF-R Signaling in the Survival and Maintenance of Mature B Cells

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    Defects in the expression of either BAFF (B cell activating factor) or BAFF-R impairs B cell development beyond the immature, transitional type-1 stage and thus, prevents the formation of follicular and marginal zone B cells, whereas B-1 B cells remain unaffected. The expression of BAFF-R on all mature B cells might suggest a role for BAFF-R signaling also for their in vivo maintenance. Here, we show that, 14 days following a single injection of an anti-BAFF-R mAb that prevents BAFF binding, both follicular and marginal zone B cell numbers are drastically reduced, whereas B-1 cells are not affected. Injection of control, isotype-matched but non-blocking anti-BAFF-R mAbs does not result in B cell depletion. We also show that this depletion is neither due to antibody-dependent cellular cytotoxicity nor to complement-mediated lysis. Moreover, prevention of BAFF binding leads to a decrease in the size of the B cell follicles, an impairment of a T cell dependent humoral immune response and a reduction in the formation of memory B cells. Collectively, these results establish a central role for BAFF-BAFF-R signaling in the in vivo survival and maintenance of both follicular and marginal zone B cell pools

    Postnatal Pancreatic Islet β Cell Function and Insulin Sensitivity at Different Stages of Lifetime in Rats Born with Intrauterine Growth Retardation

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    Epidemiological studies have linked intrauterine growth retardation (IUGR) to the metabolic diseases, consisting of insulin resistance, type 2 diabetes, obesity and coronary artery disease, during adult life. To determine the internal relationship between IUGR and islet β cell function and insulin sensitivity, we established the IUGR model by maternal nutrition restriction during mid- to late-gestation. Glucose tolerance test and insulin tolerance test(ITT) in vivo and glucose stimulated insulin secretion(GSIS) test in vitro were performed at different stages in IUGR and normal groups. Body weight, pancreas weight and pancreas/body weight of IUGR rats were much lower than those in normal group before 3 weeks of age. While the growth of IUGR rats accelerated after 3 weeks, pancreas weight and pancreas/body weight remained lower till 15 weeks of age. In the newborns, the fasting glucose and insulin levels of IUGR rats were both lower than those of controls, whereas glucose levels at 120 and 180 min after glucose load were significantly higher in IUGR group. Between 3 and 15 weeks of age, both the fasting glucose and insulin levels were elevated and the glucose tolerance was impaired with time in IUGR rats. At age 15 weeks, the area under curve of insulin(AUCi) after glucose load in IUGR rats elevated markedly. Meanwhile, the stimulating index of islets in IUGR group during GSIS test at age 15 weeks was significantly lower than that of controls. ITT showed no significant difference in two groups before 7 weeks of age. However, in 15-week-old IUGR rats, there was a markedly blunted glycemic response to insulin load compared with normal group. These findings demonstrate that IUGR rats had both impaired pancreatic development and deteriorated glucose tolerance and insulin sensitivity, which would be the internal causes why they were prone to develop type 2 diabetes

    Bacterial adaptation is constrained in complex communities

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    © 2020, The Author(s). A major unresolved question is how bacteria living in complex communities respond to environmental changes. In communities, biotic interactions may either facilitate or constrain evolution depending on whether the interactions expand or contract the range of ecological opportunities. A fundamental challenge is to understand how the surrounding biotic community modifies evolutionary trajectories as species adapt to novel environmental conditions. Here we show that community context can dramatically alter evolutionary dynamics using a novel approach that ‘cages’ individual focal strains within complex communities. We find that evolution of focal bacterial strains depends on properties both of the focal strain and of the surrounding community. In particular, there is a stronger evolutionary response in low-diversity communities, and when the focal species have a larger genome and are initially poorly adapted. We see how community context affects resource usage and detect genetic changes involved in carbon metabolism and inter-specific interaction. The findings demonstrate that adaptation to new environmental conditions should be investigated in the context of interspecific interactions

    Early influences on cardiovascular and renal development

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    The hypothesis that a developmental component plays a role in subsequent disease initially arose from epidemiological studies relating birth size to both risk factors for cardiovascular disease and actual cardiovascular disease prevalence in later life. The findings that small size at birth is associated with an increased risk of cardiovascular disease have led to concerns about the effect size and the causality of the associations. However, recent studies have overcome most methodological flaws and suggested small effect sizes for these associations for the individual, but an potential important effect size on a population level. Various mechanisms underlying these associations have been hypothesized, including fetal undernutrition, genetic susceptibility and postnatal accelerated growth. The specific adverse exposures in fetal and early postnatal life leading to cardiovascular disease in adult life are not yet fully understood. Current studies suggest that both environmental and genetic factors in various periods of life may underlie the complex associations of fetal growth retardation and low birth weight with cardiovascular disease in later life. To estimate the population effect size and to identify the underlying mechanisms, well-designed epidemiological studies are needed. This review is focused on specific adverse fetal exposures, cardiovascular adaptations and perspectives for new studies. Copyrigh

    Early influences on cardiovascular and renal development

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    Modeling risk factors and confounding effects in stroke

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