The reactivity of oytho-methoxy-substituted catechol radicals with sulfhydryl groups: Contribution for the comprehension of the mechanism of inhibition of NADPH oxidase by apocynin

Redox processes are involved in the mechanism of action of NADPH oxidase inhibitors such as diphenyleneiodonium and apocynin. Here, we studied the structure-activity relationship for apocynin and analogous ortho-methoxy-substituted catechols as inhibitors of the NADPH oxidase in neutrophils and their reactivity with peroxidase. Aiming to alter the reduction potential, the ortho-methoxy-catechol moiety was kept constant and the substituents at para position related to the hydroxyl group were varied. Two series of compounds were employed: methoxy-catechols bearing electron-withdrawing groups (MC-W) such as apocynin, vanillin, 4-nitroguaiacol, 4-cyanoguaiacol, and methoxy-catechol bearing electron-donating groups (MC-D) such as 4-methylguaiacol and 4-ethylguaiacol. We found that MC-D were weaker inhibitors compared to MD-W. Furthermore, the radicals generated by oxidation of MC-W via MPO/H(2)O(2), but not for MC-D, were able to oxidize glutathione (GSH) as verified by the formation of thiyl radicals, depletion of GSH, and recycling of the ortho-methoxy-catechols during their oxidations. The capacity of oxidizing sulfhydryl (SH) groups was also verified when ovalbumin was incubated with MC-W, but not for MC-D. Since the effect of apocynin has been correlated with inactivation of the cytosolic fractions of the NADPH oxidase complex and its oxidation during the inhibitory process develops a special role in this process, we suggest that the close relationship between the reactivity of the radicals of MC-W compounds with thiol groups and their efficacy as NADPH oxidase inhibitor could be the chemical pathway behind the mechanism of action of apocynin and should be taken into account in the design of new and specific NADPH oxidase inhibitors. (c) 2007 Elsevier B.V. All rights reserved.

Construction and validation of an instrument to assess the reading comprehension of students from the third to the fifth grades of elementary school

Objetivo:Este estudo teve como objetivo construir e validar um instrumento de avaliação da compreensão de leitura a fim de caracterizar o perfil de leitura e detectar dificuldades de compreensão em escolares do terceiro ao quinto ano do Ensino Fundamental.Métodos:Participaram 378 escolares divididos em trés grupos para avaliação da compreensão de proposições literais e inferenciais de micro e macroestruturas de dois textos expositivos e dois textos narrativos por meio de questões de múltipla escolha.Resultados:Os dados analisados estatisticamente indicaram valores do teste alfa de Cronbach apresentando consisténcia interna nos quatros textos aplicados para os trés grupos.Conclusão:Foi possível constatar que os escolares apresentaram menor número de erros com o aumento da escolarização e que cada tipo de texto apresentou uma dificuldade específica para os escolares.

FINITE ELEMENT SIMULATIONS FOR THE COMPREHENSION OF PHYSICAL PHENOMENA INVOLVED IN ELECTRIC IMPEDANCE TOMOGRAPHY OF MASONRY STRUCTURES

The paper describes the preliminary studies of University of Minho on the use of Electric Impedance/Resistance Tomography to assess masonry structures. The study is focused on the analysis of values of current and voltage resulting from the use of an electrical source with voltage and frequency values from a distribution network. The analysis is made from results obtained through computer simulations, using a three-dimensional model of the idealized masonry structures. A finite element program was used for the simulations. Three types of electrodes were used in simulations, and the analysis of the results led to significant conclusions. Later masonry specimens were built and a series of preliminary tests were carried out in the laboratory. The comparative analysis of simulated and experimental results allowed identifying the factors that have influence on the physical results.

A sociologia de Gilberto Freyre e a educação para a saúde

No contexto reavaliador dos escritos de Gilberto Freyre, pouco tem sido abordado das idéias deste autor no referente à compreensão do Homem como uma entidade ao mesmo tempo biológica e cultural. Este artigo tem como objetivo apresentar as principais propostas freyrianas no campo da sociologia da medicina e, na sequência, avaliar as possibilidades de aplicação dessas idéias nas iniciativas voltadas para a educação para a saúde.