Extinction Debt in Source-Sink Metacommunities

In an increasingly modified world, understanding and predicting the consequences of landscape alteration on biodiversity is a challenge for ecologists. To this end, metacommunity theory has developed to better understand the complexity of local and regional interactions that occur across larger landscapes. While metacommunity ecology has now provided several alternative models of species coexistence at different spatial scales, predictions regarding the consequences of landscape alteration have been done exclusively for the competition-colonization trade off model (CC). In this paper we investigate the effects of landscape perturbation on source-sink metacommunities. We show that habitat destruction perturbs the equilibria among species competitive effects within the metacommunity, driving both direct extinctions and an indirect extinction debt. As in CC models, we found a time lag for extinction following habitat destruction that varied in length depending upon the relative importance of direct and indirect effects. However, in contrast to CC models, we found that the less competitive species are more affected by habitat destruction. The best competitors can sometimes even be positively affected by habitat destruction, which corresponds well with the results of field studies. Our results are complementary to those results found in CC models of metacommunity dynamics. From a conservation perspective, our results illustrate that landscape alteration jeopardizes species coexistence in patchy landscapes through complex indirect effects and delayed extinctions patterns

Neutrophil activation induced by ArtinM: Release of inflammatory mediators and enhancement of effector functions

The D-mannose binding lectin ArtinM from Artocarpus integrifolia, previously known as KM+ and artocarpin. is considered a stimulant of Th1-type immunity, which is able to confer resistance to some intracellular pathogens. In addition, ArtinM induces neutrophil migration by haptotaxis through simultaneous interactions of its carbohydrate recognition domains (CRDs) with glycans expressed on the extracellular matrix and the neutrophil surface. In the present study, we have expanded the characterization of ArtinM as a neutrophil activator. Exposure of neutrophils to ArtinM for 15 min resulted in tyrosine phosphorylation of intracellular proteins, a process that was selectively inhibited by D-mannose or mannotriose. Shortly after stimulation, neutrophils secreted high levels of LTB(4) and underwent shedding of L-selectin from their surface. Exposure to ArtinM enhanced neutrophil functions, such as respiratory burst and zymozan and Listeria monocytogenes phagocytosis. In addition, ArtinM-stimulated neutrophils displayed increased CXCL-8 secretion and TLR2 gene transcription. These results demonstrate that ArtinM is able to induce potent neutrophil activation, a feature that should be strongly considered in the assessment of the lectin capacity to confer resistance against infections. (C) 2009 Elsevier B.V. All rights reserved.FAPESPCNPqCAPESFAEP

Perfil de morbidade e de mortalidade de pacientes idosos hospitalizados Morbidity and mortality profile of hospitalized elderly patients

Os objetivos deste estudo são analisar o perfil de morbi-mortalidade em idosos hospitalizados em dois hospitais universitários e dois não universitários, da Área de planejamento 2.2 da cidade do Rio de Janeiro, Brasil, no ano de 1999, comparando as taxas de mortalidade hospitalar, ajustando para diferenças no perfil. Os dados foram obtidos do Sistema de Informações Hospitalares do Sistema Único de Saúde (SIH/SUS). O modelo logístico foi ajustado incluindo as variáveis idade e diagnóstico primário, utilizado para calcular as taxas de mortalidade hospitalar ajustadas. As internações hospitalares em idosos (n = 7.584) representaram 29,3% do total de 25.928 internações realizadas nessas unidades. Catarata senil (7,8%) foi a causa mais freqüente, seguida de hiperplasia de próstata (4,7%), insuficiência cardíaca congestiva (2,9%) e bloqueio atrioventricular total (2,8%). Os hospitais não universitários apresentaram taxas de mortalidade hospitalar maiores do que as dos hospitais universitários, mesmo depois do ajuste para diferenças no perfil de casos em relação à idade e diagnóstico principal. O uso dos bancos de dados do SIH/SUS e da metodologia de ajuste de risco representam uma alternativa para avaliações exploratórias de resultados de cuidados de saúde.<br>The objectives of this study were to analyze the morbidity and mortality profile in elderly patients hospitalized in two teaching and two non-teaching hospitals in Rio de Janeiro, Brazil (Municipal Planning Area 2.2) in 1999, and to compare in-hospital mortality rates adjusted for differences in profile. Data were obtained from the National Hospital Database of the Unified National Health System (SIH/SUS). The logistic model included the variables age and primary diagnosis to calculate risk-adjusted in-hospital mortality rates. Hospital admissions of elderly patients (n = 7,584) represented 29.3% of a total of 25,928 hospitalizations that took place in these units. Senile cataract (7.8%) was the most frequent cause of hospitalization, followed by prostate hyperplasia (4.7%), congestive heart failure (2.9%), and complete atrioventricular block (2.8%). Non-teaching hospitals presented in-hospital mortality rates higher than teaching hospitals even after adjusting for case profile differences with regard to age and primary diagnosis. The use of SIH/SUS databases and the risk adjustment methodology represent an alternative for exploratory analysis of healthcare outcomes