Universidade Federal de Minas Gerais

About: Universidade Federal de Minas Gerais is a education organization based out in Belo Horizonte, Minas Gerais, Brazil. It is known for research contribution in the topics: Population & Immune system. The organization has 41631 authors who have published 75688 publications receiving 1249905 citations.

A role for gut microbiota and the metabolite-sensing receptor GPR43 in a murine model of gout

Abstract: Objective Host–microbial interactions are central in health and disease. Monosodium urate monohydrate (MSU) crystals cause gout by activating the NLRP3 inflammasome, leading to interleukin-1β (IL-1β) production and neutrophil recruitment. This study was undertaken to investigate the relevance of gut microbiota, acetate, and the metabolite-sensing receptor GPR43 in regulating inflammation in a murine model of gout. Methods Gout was induced by the injection of MSU crystals into the knee joints of mice. Macrophages from the various animals were stimulated to determine inflammasome activation and production of reactive oxygen species (ROS). Results Injection of MSU crystals caused joint inflammation, as seen by neutrophil influx, hypernociception, and production of IL-1β and CXCL1. These parameters were greatly decreased in germ-free mice, mice treated with antibiotics, and GPR-43–deficient mice. Recolonization or administration of acetate to germ-free mice restored inflammation in response to injection of MSU crystals. In vitro, macrophages produced ROS and assembled the inflammasome when stimulated with MSU. Macrophages from germ-free animals produced little ROS, and there was little inflammasome assembly. Similar results were observed in macrophages from GPR-43–deficient mice. Treatment of germ-free mice with acetate restored in vitro responsiveness of macrophages to MSU crystals. Conclusion In the absence of microbiota, there is decreased production of short-chain fatty acids that are necessary for adequate inflammasome assembly and IL-1β production in a manner that is at least partially dependent on GPR43. These results clearly show that the commensal microbiota shapes the host's ability to respond to an inflammasome-dependent acute inflammatory stimulus outside the gut.

Bird Extinctions in Atlantic Forest Fragments of the Viçosa Region, Southeastern Brazil

Abstract: : We studied the conservation status of Atlantic forest birds in 43 forest fragments ranging in size from 1 to 384 ha in the Vicosa region of southeastern Brazil. We compared data from 15 years of field work with historical records from the region, mainly originating from specimens collected by Joao Moojen during the 1930s. We used published studies associated with museum data and current field work to assess the decline of forest birds during the last 70 years and to relate their disappearance to forest fragmentation and destruction. At least 28 bird species have become locally extinct, 43 are critically endangered, and 25 are vulnerable, representing 60.7% of the original forest bird community known to exist in the region. Vulnerability to fragmentation differed among guilds, forest strata, and endemicity status. Birds that feed on fruit and seeds, and those that feed on insects, were more threatened than omnivores and carnivores. Nectarivorous species were less threatened than other guilds. Moreover, terrestrial and understory birds or birds using only one forest stratum also were more likely to have been threatened. Finally, Atlantic forest endemics were more likely to have become extinct than nonendemic species. In general, sensitivity to environmental disturbance at the local level was similar to the predicted vulnerability to regional disturbance derived from the literature. Our results indicate that a serious decline of Atlantic forest birds is underway and that many other species of birds, not previously recognized as threatened, are of conservation concern. Resumen: Estudiamos el estado de conservacion de aves de bosque atlantico en 43 fragmentos de 1 a 384 ha en la Region Vicosa, al sureste de Brasil. Comparamos datos de 15 anos de trabajo de campo con registros historicos de la region, principalmente de especimenes colectados por Joao Moojen durante la decada de los anos 30. Utilizamos estudios publicados asociados con datos de museo y de trabajo de campo reciente para analizar la disminuicion de aves de bosque durante los ultimos 70 anos y para relacionar su desaparicion con la fragmentacion y destruccion del bosque. Se han extinguido por lo menos 28 especies de aves localmente, 43 estan criticamente en peligro y 25 son vulnerables, lo cual representa el 60,7% de la comunidad de aves de bosque conocida para la region. La vulnerabilidad a la fragmentacion fue diferente entre gremios, estratos de bosque y estado de endemismo. Las aves que se alimentan de frutos y semillas y aquellas que se alimentan de insectos estan mas amenazadas que las omnivoras y carnivoras. Las especies nectarivoras estan menos amenazadas que otros gremios. Mas aun, las aves terrestres y de sotobosque o las que utilizan solo un estrato del bosque tambien tienen mayor probabilidad de estar amenazadas. Finalmente, las aves endemicas al bosque atlantico tienen mayor probabilidad de extincion que las no endemicas. En general, la sensibilidad a la perturbacion ambiental a nivel local fue similar a la vulnerabilidad a la perturbacion regional predicha, derivada de la bibliografia. Nuestros resultados indican que existe una seria declinacion de aves de bosque atlantico y que muchas otras especies de aves, no reconocidas como amenazadas previamente, son de interes para la conservacion.

Context-Aware Event Recommendation in Event-based Social Networks

Abstract: The Web has grown into one of the most important channels to communicate social events nowadays. However, the sheer volume of events available in event-based social networks (EBSNs) often undermines the users' ability to choose the events that best fit their interests. Recommender systems appear as a natural solution for this problem, but differently from classic recommendation scenarios (e.g. movies, books), the event recommendation problem is intrinsically cold-start. Indeed, events published in EBSNs are typically short-lived and, by definition, are always in the future, having little or no trace of historical attendance. To overcome this limitation, we propose to exploit several contextual signals available from EBSNs. In particular, besides content-based signals based on the events' description and collaborative signals derived from users' RSVPs, we exploit social signals based on group memberships, location signals based on the users' geographical preferences, and temporal signals derived from the users' time preferences. Moreover, we combine the proposed signals for learning to rank events for personalized recommendation. Thorough experiments using a large crawl of Meetup.com demonstrate the effectiveness of our proposed contextual learning approach in contrast to state-of-the-art event recommenders from the literature.

Reference equations for the six-minute walk distance based on a Brazilian multicenter study

Abstract: Background: It is important to include large sample sizes and different factors that influence the six- minute walking distance (6MWD) in order to propose reference equations for the six-minute walking test (6MWT). Objective: To evaluate the influence of anthropometric, demographic, and physiologic variables on the 6MWD of healthy subjects from different regions of Brazil to establish a reference equation for the Brazilian population. Method: In a multicenter study, 617 healthy subjects performed two 6MWTs and had their weight, height, and body mass index (BMI) measured, as well as their physiologic responses to the test. Delta heart rate (∆HR), perceived effort, and peripheral oxygen saturation were calculated by the difference between the respective values at the end of the test minus the baseline value. Results: Walking distance averaged 586±106m, 54m greater in male compared to female subjects (p<0.001). No differences were observed among the 6MWD from different regions. The quadratic regression analysis considering only anthropometric and demographic data explained 46% of the variability in the 6MWT (p<0.001) and derived the equation: 6MWD pred =890.46-(6.11×age)+(0.0345×age 2 )+(48.87×gender)-(4.87×BMI). A second model of stepwise multiple regression including ∆HR explained 62% of the variability (p<0.0001) and derived the equation: 6MWD pred =356.658-(2.303×age)+(36.648×gender)+(1.704×height)+(1.365×∆HR). Conclusion: The equations proposed in this study, especially the second one, seem adequate to accurately predict the 6MWD for Brazilians.