29 research outputs found

    Sex-Specific Heterosis in Line Crosses of Mice Selectively Bred for High Locomotor Activity

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    When populations with similar histories of directional selection are crossed, their offspring may differ in mean phenotype as compared with the average for the parental populations, often exhibiting enhancement of the mean phenotype (termed heterosis or hybrid vigor). We tested for heterosis in a cross of two replicate lines of mice selectively bred for high voluntary wheel running for 53 generations. Mice were paired to produce four sets of F1 offspring: two purebred High Runner (HR) lines and the hybrid reciprocal crosses. The purebred HR showed statistically significant, sex-dependent differences in body mass, wheel revolutions, running duration, mean running speed, and (controlling for body mass) organ masses (heart ventricles, liver, spleen, triceps surae muscle). Hybrid males ran significantly more revolutions than the purebred males, mainly via increased running speeds, but hybrid females ran intermediate distances, durations, and speeds, as compared with the purebred females. In both sexes, ventricles were relatively smaller in hybrids as compared with purebred HR. Overall, our results demonstrate differential and sex-specific responses to selection in the two HR lines tested, implying divergent genetic architectures underlying high voluntary exercise

    Genetic mechanisms of critical illness in COVID-19.

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    Host-mediated lung inflammation is present1, and drives mortality2, in the critical illness caused by coronavirus disease 2019 (COVID-19). Host genetic variants associated with critical illness may identify mechanistic targets for therapeutic development3. Here we report the results of the GenOMICC (Genetics Of Mortality In Critical Care) genome-wide association study in 2,244 critically ill patients with COVID-19 from 208 UK intensive care units. We have identified and replicated the following new genome-wide significant associations: on chromosome 12q24.13 (rs10735079, P = 1.65 × 10-8) in a gene cluster that encodes antiviral restriction enzyme activators (OAS1, OAS2 and OAS3); on chromosome 19p13.2 (rs74956615, P = 2.3 × 10-8) near the gene that encodes tyrosine kinase 2 (TYK2); on chromosome 19p13.3 (rs2109069, P = 3.98 ×  10-12) within the gene that encodes dipeptidyl peptidase 9 (DPP9); and on chromosome 21q22.1 (rs2236757, P = 4.99 × 10-8) in the interferon receptor gene IFNAR2. We identified potential targets for repurposing of licensed medications: using Mendelian randomization, we found evidence that low expression of IFNAR2, or high expression of TYK2, are associated with life-threatening disease; and transcriptome-wide association in lung tissue revealed that high expression of the monocyte-macrophage chemotactic receptor CCR2 is associated with severe COVID-19. Our results identify robust genetic signals relating to key host antiviral defence mechanisms and mediators of inflammatory organ damage in COVID-19. Both mechanisms may be amenable to targeted treatment with existing drugs. However, large-scale randomized clinical trials will be essential before any change to clinical practice

    Trajectories of Viral Suppression in People Living With HIV Receiving Coordinated Care: Differences by Comorbidities.

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    BackgroundIn March of 2013, the Los Angeles County (LAC) Division of HIV and STD Programs implemented a clinic-based Medical Care Coordination (MCC) Program to increase viral suppression (VS) (<200 c/mL) among people living with HIV (PLWH) at high risk for poor health outcomes.ObjectiveThis study aimed to estimate trajectories of VS and to assess whether these trajectories differed by stimulant use, housing instability, and depressive symptom severity as reported by PLWH participating in MCC.MethodsData represent 6408 PLWH in LAC receiving services from the MCC Program and were obtained from LAC HIV surveillance data matched to behavioral assessments obtained across 35 Ryan White Program clinics participating in MCC. Piecewise mixed-effects logistic regression with a random intercept estimated probabilities of VS from 12 months before MCC enrollment through 36 months after enrollment, accounting for time by covariate interactions for 3 comorbid conditions: housing instability, stimulant use, and depressive symptoms.ResultsThe overall probability of VS increased from 0.35 to 0.77 within the first 6 months in the MCC Program, and this probability was maintained up to 36 months after enrollment. Those who reported housing instability, stimulant use, or multiple comorbid conditions did not achieve the same probability of VS by 36 months as those with none of those comorbidities.ConclusionsFindings suggest that MCC improved the probability of VS for all patient groups regardless of the presence of comorbidities. However, those with comorbid conditions will still require increased support from patient-centered programs to address disparities in VS
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