29 research outputs found

    Immune monitoring-guided vs fixed duration of antiviral prophylaxis against cytomegalovirus in solid-organ transplant recipients. A Multicenter, Randomized Clinical Trial.

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    BACKGROUND The use of assays detecting cytomegalovirus (CMV)-specific T-cell-mediated immunity may individualize the duration of antiviral prophylaxis in transplant recipients. METHODS In this open-label randomized trial, adult kidney and liver transplant recipients from six centers in Switzerland were enrolled if they were CMV-seronegative with seropositive donors or CMV-seropositive receiving anti-thymocyte globulins. Patients were randomized to a duration of antiviral prophylaxis based on immune-monitoring (intervention) or a fixed duration (control). Patients in the control group were planned to receive 180 days (CMV-seronegative) or 90 days (CMV-seropositive) of valganciclovir. Patients were assessed monthly with a CMV-specific interferon gamma release assay (T-Track® CMV); prophylaxis in the intervention group was stopped if the assay was positive. The primary outcomes were the proportion of patients with clinically significant CMV infection and reduction in days of prophylaxis. Between-group differences were adjusted for CMV serostatus. RESULTS Overall, 193 patients were randomized (92 in the immune-monitoring and 101 in the control group) of which 185 had evaluation of the primary endpoint (87 and 98 patients, respectively). Clinically significant CMV infection occurred in 26/87 (adjusted percentage, 30.9%) in the immune-monitoring group and in 32/98 (adjusted percentage, 31.1%) in the control group (adjusted risk difference -0.1, 95%CI -13.0%, 12.7%; p = 0.064). The duration of antiviral prophylaxis was shorter in the immune-monitoring group (adjusted difference -26.0 days, 95%-CI -41.1 to -10.8 days, p < 0.001). CONCLUSIONS Immune monitoring resulted in a significant reduction of antiviral prophylaxis, but we were unable to establish noninferiority of this approach on the co-primary endpoint of CMV infection

    Can Non-lytic CD8+T Cells Drive HIV-1 Escape?

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    The CD8+ T cell effector mechanisms that mediate control of HIV-1 and SIV infections remain poorly understood. Recent work suggests that the mechanism may be primarily non-lytic. This is in apparent conflict with the observation that SIV and HIV-1 variants that escape CD8+ T cell surveillance are frequently selected. Whilst it is clear that a variant that has escaped a lytic response can have a fitness advantage compared to the wild-type, it is less obvious that this holds in the face of non-lytic control where both wild-type and variant infected cells would be affected by soluble factors. In particular, the high motility of T cells in lymphoid tissue would be expected to rapidly destroy local effects making selection of escape variants by non-lytic responses unlikely. The observation of frequent HIV-1 and SIV escape poses a number of questions. Most importantly, is the consistent observation of viral escape proof that HIV-1- and SIV-specific CD8+ T cells lyse infected cells or can this also be the result of non-lytic control? Additionally, the rate at which a variant strain escapes a lytic CD8+ T cell response is related to the strength of the response. Is the same relationship true for a non-lytic response? Finally, the potential anti-viral control mediated by non-lytic mechanisms compared to lytic mechanisms is unknown. These questions cannot be addressed with current experimental techniques nor with the standard mathematical models. Instead we have developed a 3D cellular automaton model of HIV-1 which captures spatial and temporal dynamics. The model reproduces in vivo HIV-1 dynamics at the cellular and population level. Using this model we demonstrate that non-lytic effector mechanisms can select for escape variants but that outgrowth of the variant is slower and less frequent than from a lytic response so that non-lytic responses can potentially offer more durable control

    Target genes, variants, tissues and transcriptional pathways influencing human serum urate levels.

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    Elevated serum urate levels cause gout and correlate with cardiometabolic diseases via poorly understood mechanisms. We performed a trans-ancestry genome-wide association study of serum urate in 457,690 individuals, identifying 183 loci (147 previously unknown) that improve the prediction of gout in an independent cohort of 334,880 individuals. Serum urate showed significant genetic correlations with many cardiometabolic traits, with genetic causality analyses supporting a substantial role for pleiotropy. Enrichment analysis, fine-mapping of urate-associated loci and colocalization with gene expression in 47 tissues implicated the kidney and liver as the main target organs and prioritized potentially causal genes and variants, including the transcriptional master regulators in the liver and kidney, HNF1A and HNF4A. Experimental validation showed that HNF4A transactivated the promoter of ABCG2, encoding a major urate transporter, in kidney cells, and that HNF4A p.Thr139Ile is a functional variant. Transcriptional coregulation within and across organs may be a general mechanism underlying the observed pleiotropy between urate and cardiometabolic traits.The Genotype-Tissue Expression (GTEx) Project was supported by the Common Fund of the Office of the Director of the National Institutes of Health, and by NCI, NHGRI, NHLBI, NIDA, NIMH, and NINDS. Variant annotation was supported by software resources provided via the Caché Campus program of the InterSystems GmbH to Alexander Teumer

    Genome-wide association meta-analyses and fine-mapping elucidate pathways influencing albuminuria

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    Publisher Copyright: © 2019, The Author(s).Increased levels of the urinary albumin-to-creatinine ratio (UACR) are associated with higher risk of kidney disease progression and cardiovascular events, but underlying mechanisms are incompletely understood. Here, we conduct trans-ethnic (n = 564,257) and European-ancestry specific meta-analyses of genome-wide association studies of UACR, including ancestry- and diabetes-specific analyses, and identify 68 UACR-associated loci. Genetic correlation analyses and risk score associations in an independent electronic medical records database (n = 192,868) reveal connections with proteinuria, hyperlipidemia, gout, and hypertension. Fine-mapping and trans-Omics analyses with gene expression in 47 tissues and plasma protein levels implicate genes potentially operating through differential expression in kidney (including TGFB1, MUC1, PRKCI, and OAF), and allow coupling of UACR associations to altered plasma OAF concentrations. Knockdown of OAF and PRKCI orthologs in Drosophila nephrocytes reduces albumin endocytosis. Silencing fly PRKCI further impairs slit diaphragm formation. These results generate a priority list of genes and pathways for translational research to reduce albuminuria.Peer reviewe

    Genetic loci and prioritization of genes for kidney function decline derived from a meta-analysis of 62 longitudinal genome-wide association studies

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    Estimated glomerular filtration rate (eGFR) reflects kidney function. Progressive eGFR-decline can lead to kidney failure, necessitating dialysis or transplantation. Hundreds of loci from genome-wide association studies (GWAS) for eGFR help explain population cross section variability. Since the contribution of these or other loci to eGFR-decline remains largely unknown, we derived GWAS for annual eGFR-decline and meta-analyzed 62 longitudinal studies with eGFR assessed twice over time in all 343,339 individuals and in high-risk groups. We also explored different covariate adjustment. Twelve genome-wide significant independent variants for eGFR-decline unadjusted or adjusted for eGFR-baseline (11 novel, one known for this phenotype), including nine variants robustly associated across models were identified. All loci for eGFR-decline were known for cross-sectional eGFR and thus distinguished a subgroup of eGFR loci. Seven of the nine variants showed variant-by-age interaction on eGFR cross section (further about 350,000 individuals), which linked genetic associations for eGFR-decline with age-dependency of genetic cross-section associations. Clinically important were two to four-fold greater genetic effects on eGFR-decline in high-risk subgroups. Five variants associated also with chronic kidney disease progression mapped to genes with functional in-silico evidence (UMOD, SPATA7, GALNTL5, TPPP). An unfavorable versus favorable nine-variant genetic profile showed increased risk odds ratios of 1.35 for kidney failure (95% confidence intervals 1.03-1.77) and 1.27 for acute kidney injury (95% confidence intervals 1.08-1.50) in over 2000 cases each, with matched controls). Thus, we provide a large data resource, genetic loci, and prioritized genes for kidney function decline, which help inform drug development pipelines revealing important insights into the age-dependency of kidney function genetics

    Genome-wide association meta-analyses and fine-mapping elucidate pathways influencing albuminuria

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    Increased levels of the urinary albumin-to-creatinine ratio (UACR) are associated with higher risk of kidney disease progression and cardiovascular events, but underlying mechanisms are incompletely understood. Here, we conduct trans-ethnic (n = 564,257) and European-ancestry specific meta-analyses of genome-wide association studies of UACR, including ancestry- and diabetes-specific analyses, and identify 68 UACR-associated loci. Genetic correlation analyses and risk score associations in an independent electronic medical records database (n = 192,868) reveal connections with proteinuria, hyperlipidemia, gout, and hypertension. Fine-mapping and trans-Omics analyses with gene expression in 47 tissues and plasma protein levels implicate genes potentially operating through differential expression in kidney (including TGFB1, MUC1, PRKCI, and OAF), and allow coupling of UACR associations to altered plasma OAF concentrations. Knockdown of OAF and PRKCI orthologs in Drosophila nephrocytes reduces albumin endocytosis. Silencing fly PRKCI further impairs slit diaphragm formation. These results generate a priority list of genes and pathways for translational research to reduce albuminuria

    Sit-to-stand biomechanics : a systematic review

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    Objective: This review focuses on studies that enhance our knowledge of the biomechanics of the sit-to-stand (STS) quantitatively. The questions asked and the methods of study have led to the partitioning of the STS into components, or phases. Our goal is to summarize the methodological approaches and define the phases of a STS transfer in order to provide a standard practice for STS. Data Sources: Electronic database searches were conducted in PubMed and Google Scholar from inception to February 2021. Study Selection: Articles with a combination of the keywords “sit-to-stand”, “biomechanics”, “stability” and “postural control” were searched. Only the articles that provided quantitative biomechanical insights of the STS movement were included. Data Extraction: We categorized the studies by the questions posed, the measurement techniques used, and the definition of phases. Data Synthesis: Seventy-two papers published between 1976 and 2021 that provided quantitative biomechanical insights of the STS movement itself were included in this review. Among the studies that qualified for this review, research interest in the STS may be parsed into the following categories: a) how the movement is performed, b) use of the STS to understand postural stability, and c) use of the STS to understand clinical differences in performance. Conclusion: Definitions of events in the STS that define phases are inconsistent. The major reason identified is due to differences in the purpose of the studies or equipment used. Four studies dividing STS into 2 phases, eight studies divided STS into 3 phases, and 2 studies divided STS into 4 phases and 2 studies divided STS into 5 phases. At a minimum, the STS is typically deconstructed into two phases, with seat-off being the demarcation of transition between phases. This is based on the characteristics of muscle power or on select kinematic events. However, 10 different ways in which the event of ‘seat-off’ has been defined shows the impact of differences in measurement technique. These differences between studies result in contradictory definitions of the same event. These findings reveal a need for standardization of event definition and recommendations on measurement techniques.Kinesiology and Health Educatio

    P300

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    The concept of self and self-referential processing has a growing explanatory value in psychiatry and neuroscience, referring to the cognitive organization and perceptual differentiation of self-stimuli in health and disease. Conditions in which selfhood loses its natural coherence offer a unique opportunity for elucidating the mechanisms underlying self-disturbances. We assessed the psychoactive effects of psilocybin (230 μg/kg p.o.), a preferential 5-HT1A/2A agonist known to induce shifts in self-perception. Our placebo-controlled, double-blind, within-subject crossover experiment (n = 17) implemented a verbal self-monitoring task involving vocalizations and participant identification of real-time auditory source- (self/other) and pitch-modulating feedback. Subjective experience and task performance were analyzed, with time-point-by-time-point assumption-free multivariate randomization statistics applied to the spatiotemporal dynamics of event-related potentials. Psilocybin-modulated self-experience, interacted with source to affect task accuracy, and altered the late phase of self-stimuli encoding by abolishing the distinctiveness of self- and other-related electric field configurations during the P300 timeframe. This last effect was driven by current source density changes within the supragenual anterior cingulate and right insular cortex. The extent of the P300 effect was associated with the intensity of psilocybin-induced feelings of unity and changed meaning of percepts. Modulations of late encoding and their underlying neural generators in self-referential processing networks via 5-HT signaling may be key for understanding self-disorders. This mechanism may reflect a neural instantiation of altered self-other and relational meaning processing in a stimulus-locked time domain. The study elucidates the neuropharmacological foundation of subjectivity, with implications for therapy, underscoring the concept of connectedness

    Genetic loci and prioritization of genes for kidney function decline derived from a meta-analysis of 62 longitudinal genome-wide association studies

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