56 research outputs found
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Reduced injury risk links sociality to survival in a group-living primate
This is the final version. Available on open access from Cell Press via the DOI in this recordData and code availability: Data have been deposited at Mendeley Data and are publicly available as of the date of publication. DOI is listed in the key resources table. All original code has been deposited on GitHub and is publicly available as of the date of publication. The link is listed in the key resources table. Any additional information required to reanalyze the data reported in this paper is available from the lead contact upon request.Sociality has been linked to a longer lifespan in many mammals, including humans. Yet, how sociality results in survival benefits remains unclear. Using 10 years of data and over 1,000 recorded injuries in rhesus macaques (Macaca mulatta), we tested two injury-related mechanisms by which social status and affiliative partners might influence survival. Injuries increased individual risk of death by 3-fold in this dataset. We found that sociality can affect individuals’ survival by reducing their risk of injury but had no effect on the probability of injured individuals dying. Both males and females of high social status (measured as female matrilineal rank and male group tenure) and females with more affiliative partners (estimated using the number of female relatives) experienced fewer injuries and thus were less likely to die. Collectively, our results offer rare insights into one mechanism that can mediate the well-known benefits of sociality on an individual’s fitness.ANID-Chilean scholarshipNational Institutes of Health (NIH)European Research Council (ERC)MacCracken FellowshipNational Science Foundation (NSF
Recommended from our members
Reduced injury risk links sociality to survival in a group-living primate
Sociality has been linked to a longer lifespan in many mammals, including humans. Yet, how sociality results in survival benefits remains unclear. Using 10 years of data and over 1,000 recorded injuries in rhesus macaques (Macaca mulatta), we tested two injury-related mechanisms by which social status and affiliative partners might influence survival. Injuries increased individual risk of death by 3-fold in this dataset. We found that sociality can affect individuals’ survival by reducing their risk of injury but had no effect on the probability of injured individuals dying. Both males and females of high social status (measured as female matrilineal rank and male group tenure) and females with more affiliative partners (estimated using the number of female relatives) experienced fewer injuries and thus were less likely to die. Collectively, our results offer rare insights into one mechanism that can mediate the well-known benefits of sociality on an individual’s fitness
Radiation-induced skin injury in the animal model of scleroderma: implications for post-radiotherapy fibrosis
<p>Abstract</p> <p>Background</p> <p>Radiation therapy is generally contraindicated for cancer patients with collagen vascular diseases (CVD) such as scleroderma due to an increased risk of fibrosis. The tight skin (TSK) mouse has skin which, in some respects, mimics that of patients with scleroderma. The skin radiation response of TSK mice has not been previously reported. If TSK mice are shown to have radiation sensitive skin, they may prove to be a useful model to examine the mechanisms underlying skin radiation injury, protection, mitigation and treatment.</p> <p>Methods</p> <p>The hind limbs of TSK and parental control C57BL/6 mice received a radiation exposure sufficient to cause approximately the same level of acute injury. Endpoints included skin damage scored using a non-linear, semi-quantitative scale and tissue fibrosis assessed by measuring passive leg extension. In addition, TGF-β1 cytokine levels were measured monthly in skin tissue.</p> <p>Results</p> <p>Contrary to our expectations, TSK mice were more resistant (i.e. 20%) to radiation than parental control mice. Although acute skin reactions were similar in both mouse strains, radiation injury in TSK mice continued to decrease with time such that several months after radiation there was significantly less skin damage and leg contraction compared to C57BL/6 mice (p < 0.05). Consistent with the expected association of transforming growth factor beta-1 (TGF-β1) with late tissue injury, levels of the cytokine were significantly higher in the skin of the C57BL/6 mouse compared to TSK mouse at all time points (p < 0.05).</p> <p>Conclusion</p> <p>TSK mice are not recommended as a model of scleroderma involving radiation injury. The genetic and molecular basis for reduced radiation injury observed in TSK mice warrants further investigation particularly to identify mechanisms capable of reducing tissue fibrosis after radiation injury.</p
The absence of MyD88 has no effect on the induction of alternatively activated macrophage during Fasciola hepatica infection
<p>Abstract</p> <p>Background</p> <p>Alternatively activated macrophages (AAMϕ) play important roles in allergies and responses to parasitic infections. However, whether signaling through toll-like receptors (TLRs) plays any role in AAMϕ induction when young <it>Fasciola hepatica </it>penetrates the liver capsule and migrates through the liver tissue is still unclear.</p> <p>Results</p> <p>The data show that the lack of myeloid differentiation factor 88 (MyD88) has no effect on the AAMϕ derived from the bone marrow (BMMϕ) <it>in vitro </it>and does not impair the mRNA expression of arginase-1, resistin-like molecule (RELMα), and Ym1 in BMMϕs. The Th2 cytokine production bias in splenocytes was not significantly altered in <it>F. hepatica</it>-infected mice in the absence of MyD88 <it>in vitro </it>and in the pleural cavity lavage <it>in vivo</it>. In addition, MyD88-deficiency has no effect on the arginase production of the <it>F. hepatica </it>elicited macrophages (Fe Mϕs), production of RELMα and Ym1 proteins and mRNA expression of Ym1 and RELMα of macrophages in the peritoneal cavity 6 weeks post <it>F. hepatica </it>infection.</p> <p>Conclusions</p> <p>The absence of MyD88 has no effect on presence of AAMϕ 6 weeks post <it>F. hepatica </it>infection.</p
Systematic review of the evidence relating FEV1 decline to giving up smoking
<p>Abstract</p> <p>Background</p> <p>The rate of forced expiratory volume in 1 second (FEV<sub>1</sub>) decline ("beta") is a marker of chronic obstructive pulmonary disease risk. The reduction in beta after quitting smoking is an upper limit for the reduction achievable from switching to novel nicotine delivery products. We review available evidence to estimate this reduction and quantify the relationship of smoking to beta.</p> <p>Methods</p> <p>Studies were identified, in healthy individuals or patients with respiratory disease, that provided data on beta over at least 2 years of follow-up, separately for those who gave up smoking and other smoking groups. Publications to June 2010 were considered. Independent beta estimates were derived for four main smoking groups: never smokers, ex-smokers (before baseline), quitters (during follow-up) and continuing smokers. Unweighted and inverse variance-weighted regression analyses compared betas in the smoking groups, and in continuing smokers by amount smoked, and estimated whether beta or beta differences between smoking groups varied by age, sex and other factors.</p> <p>Results</p> <p>Forty-seven studies had relevant data, 28 for both sexes and 19 for males. Sixteen studies started before 1970. Mean follow-up was 11 years. On the basis of weighted analysis of 303 betas for the four smoking groups, never smokers had a beta 10.8 mL/yr (95% confidence interval (CI), 8.9 to 12.8) less than continuing smokers. Betas for ex-smokers were 12.4 mL/yr (95% CI, 10.1 to 14.7) less than for continuing smokers, and for quitters, 8.5 mL/yr (95% CI, 5.6 to 11.4) less. These betas were similar to that for never smokers. In continuing smokers, beta increased 0.33 mL/yr per cigarette/day. Beta differences between continuing smokers and those who gave up were greater in patients with respiratory disease or with reduced baseline lung function, but were not clearly related to age or sex.</p> <p>Conclusion</p> <p>The available data have numerous limitations, but clearly show that continuing smokers have a beta that is dose-related and over 10 mL/yr greater than in never smokers, ex-smokers or quitters. The greater decline in those with respiratory disease or reduced lung function is consistent with some smokers having a more rapid rate of FEV<sub>1 </sub>decline. These results help in designing studies comparing continuing smokers of conventional cigarettes and switchers to novel products.</p
A new class of glycomimetic drugs to prevent free fatty acid-induced endothelial dysfunction
Background: Carbohydrates play a major role in cell signaling in many biological processes. We have developed a set of glycomimetic drugs that mimic the structure of carbohydrates and represent a novel source of therapeutics for endothelial dysfunction, a key initiating factor in cardiovascular complications. Purpose: Our objective was to determine the protective effects of small molecule glycomimetics against free fatty acidinduced endothelial dysfunction, focusing on nitric oxide (NO) and oxidative stress pathways. Methods: Four glycomimetics were synthesized by the stepwise transformation of 2,5dihydroxybenzoic acid to a range of 2,5substituted benzoic acid derivatives, incorporating the key sulfate groups to mimic the interactions of heparan sulfate. Endothelial function was assessed using acetylcholineinduced, endotheliumdependent relaxation in mouse thoracic aortic rings using wire myography. Human umbilical vein endothelial cell (HUVEC) behavior was evaluated in the presence or absence of the free fatty acid, palmitate, with or without glycomimetics (1µM). DAF2 and H2DCFDA assays were used to determine nitric oxide (NO) and reactive oxygen species (ROS) production, respectively. Lipid peroxidation colorimetric and antioxidant enzyme activity assays were also carried out. RTPCR and western blotting were utilized to measure Akt, eNOS, Nrf2, NQO1 and HO1 expression. Results: Ex vivo endotheliumdependent relaxation was significantly improved by the glycomimetics under palmitateinduced oxidative stress. In vitro studies showed that the glycomimetics protected HUVECs against the palmitateinduced oxidative stress and enhanced NO production. We demonstrate that the protective effects of preincubation with glycomimetics occurred via upregulation of Akt/eNOS signaling, activation of the Nrf2/ARE pathway, and suppression of ROSinduced lipid peroxidation. Conclusion: We have developed a novel set of small molecule glycomimetics that protect against free fatty acidinduced endothelial dysfunction and thus, represent a new category of therapeutic drugs to target endothelial damage, the first line of defense against cardiovascular disease
Second meiotic arrest and exit in frogs and mice
Mature vertebrate oocytes typically undergo programmed arrest at the second meiotic cell cycle until they are signalled to initiate embryonic development at fertilization. Here, we describe the underlying molecular mechanisms of this second meiotic arrest and release in Xenopus, and compare and contrast them with their counterparts in mice
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