Relationship between psychological and biological factors and physical activity and exercise behaviour in Filipino students

The aim of the present study was threefold. Firstly, it investigated whether a general measure or specific measure of motivational orientation was better in describing the relationship between motivation and exercise behaviour. Secondly, it examined the relationship between the four most popular indirect methods of body composition assessment and physical activity and exercise patterns. Thirdly, the interaction between motivation and body composition on physical activity and exercise behaviour was explored in a sample of 275 Filipino male and female students. Males were found to have higher levels of exercise whereas females had higher levels of physical activity. Furthermore, general self-motivation together with body weight and percentage body fat were found to be the best predictor of exercise behaviour whereas the tension/pressure subscale of the ‘Intrinsic Motivation Inventory’ (IMI) was the best predictor of levels of physical activity. However, significant gender differences were observed. That is, for the males only self-motivation and for the females only body weight and BMI predicted exercise behaviour. Also, tension/pressure predicted physical activity levels for the females but not the males. No inverse relationship was found between the four body composition measures and exercise and physical activity behaviour. The results support the notion that the psychobiological approach might be particularly relevant for high intensity exercise situations but also highlights some important gender differences. Finally, the results of this study emphasise the need for more cross-cultural research

Immunoactivation and immunopathogeny during active visceral leishmaniasis Imunoativação e imunopatogenia durante leishmaniose visceral ativa

Visceral leishmaniasis is caused by protozoan parasites of the Leishmania donovani complex. During active disease in humans, high levels of IFN-&#947; and TNF-&#945; detected in blood serum, and high expression of IFN-&#947; mRNA in samples of the lymphoid organs suggest that the immune system is highly activated. However, studies using peripheral blood mononuclear cells have found immunosuppression specific to Leishmania antigens; this poor immune response probably results from Leishmania antigen-engaged lymphocytes being trapped in the lymphoid organs. To allow the parasites to multiply, deactivating cytokines IL-10 and TGF-&#946; may be acting on macrophages as well as anti-Leishmania antibodies that opsonize amastigotes and induce IL-10 production in macrophages. These high activation and deactivation processes are likely to occur mainly in the spleen and liver and can be confirmed through the examination of organ samples. However, an analysis of sequential data from studies of visceral leishmaniasis in hamsters suggests that factors outside of the immune system are responsible for the early inactivation of inducible nitric oxide synthase, which occurs before the expression of deactivating cytokines. In active visceral leishmaniasis, the immune system actively participates in non-lymphoid organ lesioning. While current views only consider immunocomplex deposition, macrophages, T cells, cytokines, and immunoglobulins by diverse mechanism also play important roles in the pathogenesis.<br>A leishmaniose visceral é causada por protozoários do gênero do complexo Leishmania donovani. Durante a doença ativa no homem são detectados altos níveis de IFN-&#947; e de TNF-&#945; no soro, e elevada expressão de mRNA de IFN-&#947; em amostras de órgãos linfóides sugerindo um estado intensamente ativado do sistema imunológico. A visão atual, no entanto, refere-se à imunossupressão específica aos antígenos de Leishmania com base em estudos utilizando células mononucleares do sangue periférico; a explicação para sua resposta deficiente seria provavelmente porque os linfócitos compometidos com antígeno de Leishmania são sequestrados nos órgãos linfóides. Para permitir a proliferação do parasito, citocinas desativadoras IL-10 e TGF-&#946; atuariam nos macrófagos, bem como os anticorpos anti-Leishmania opsonizando amastigotas e induzindo a produção IL-10 pelos macrófagos. Estes processos de intensa ativação e desativação provavelmente ocorreriam no baço e fígado, principalmente, e confirmados com amostras de órgãos. No entanto, analisando dados seqüenciais obtidos na leishmaniose visceral no hamster, sugere-se provável presença de fatores fora do sistema imunológico como responsável pela inativação inicial de sintase induzível do óxido nítrico que ocorre antes da expressão de citocinas desativadoras. Na leishmaniose visceral ativa o sistema imunológico participa ativamente na lesão de órgãos não linfóides. Contrária à visão existente que considera somente mecanismos de deposição de imunocomplexos, observa-se na patogenia a participação de macrófagos, células T, citocinas e imunoglobulinas por mecanismo alternativo