Influência do exercício isotônico pré-dialítico / The influence of the isotonic exercise before hemodialysis

Introdução: Uma das funções da terapia renal substitutiva é a remoção da uréia acumulada nos pacientes portadores de insuficiência renal dialítica. Parte desta uréia encontra-se no compartimento muscular, reduzindo a capacidade dialítica de remoção deste soluto. A atividade física pode ser um fator importante que possa contribuir para melhora do fluxo sanguíneo muscular e conseqüente otimização da depuração deste soluto.Este trabalho teve como objetivo analisar, utilizando-se o índice de depuração da uréia por sessão dehemodálise (Kt/V) como parâmetro de eficácia dialítica, os resultados de um programa de exercícios isotônicos pré-dialíticos na qualidade de diálise. Metodologia: Foram analisados dados de quinze pacientes com insuficiência renal crônica (IRC) de ambos os sexos, submetidos à hemodiálise três vezes por semana. Um protocolo de exercícios isotônicos de baixa intensidade precedidos por alongamentos foi aplicado por um mês, imediatamente antes da sessão de hemodiálise. Após a hemodiálise, a concentração plasmática de uréia foi mensurada, o Kt/V determinado e comparado com o do mês anterior obtido com as mesmas condições de hemodiálise quanto à duração, filtro e acesso vascular, sem a aplicação do programa de exercícios. Teste t de Student, com significância de 5%, foi utilizado para análise dos dados. Resultados: Comparando o Kt/V do mês sem exercício (1,4 ± 0,33) com os obtidos após a aplicação do programa de exercícios (1,3 ± 0.3), os valores não foram estatisticamente significativos (p > 0,05). Conclusões: Os resultados sugerem que, na amostra analisada, o programa de exercícios na intensidade, duração e freqüência executados, não resultou na melhora da eficiência dialítica.

Introduction: One of the functions of the substitutive renal therapy is to remove accumulated urea inindividuals with dialytic renal failure. Part of this urea is found in the muscular compartment reducing the dialytic capacity to remove this solute. Physical activity can be an important contributing factor to improvethe muscle blood flow and consequently the optimization of this solute depuration . The aim of this studywas to analyze the results of a program of a pre-dialytic isotonic exercise, using the standard procedure of measure (Kt/V), as a parameter of the dialysis efficacy. Methodology: Data from fifteen (15) patients from both sexes with chronic renal failure (CRF) who had undergone hemodialysis three times a week were analyzed. A protocol of low intensity isotonic exercises preceded by stretching was applied during a month, immediately before hemodialysis sessions. After hemodialysis, a urea plasmatic concentration was measured; std Kt/Vwas determined and compared with the previous month obtained through the same conditions of hemodialysis according to the length, filter and vascular access, without the exercise program. Student´s t test with 5% of significance was used for data analysis. Results: Comparing the std Kt/V during the month without exercise(1.4 ± 0.33) with the Kt/V obtained after the exercise program (1.3 ± 0.3), the values were not statistically significant (p > 0.05). Conclusions: The results of this analyzed sample have suggested that this program ofexercise carried out in the intensity, length and frequency has not resulted improvement of the dialysis efficacy

Role of parasite surface glycoconjugates on induction/regulation of immune responses and inflammation, elicited during Trypanosoma cruzi infection: potential implications on pathophysiology of Chagas" disease

To understand the interaction of Trypanosoma cruzi and the immune system of the vertebrate host, and therefore the pathophysiology of Chagas' disease, different research groups have focused their attention on the identification and characterization of parasite molecules involved in the activation of either innate or adaptive immune responses. The parasite surface molecules that serve as targets of the vertebrate host immune system have also been studied and identified. These studies have revealed that the quatitatively dominant complex of glycosylphosphatidylinositol (GPI)-anchored molecules (GIPLs, mucins and TS) present on the surface of T. cruzi trypomastigotes are essential to control activation of the innate immune system and promote initiation of acquired immune responses in the vertebrate host. Two major families of surface glycoproteins (mucin-like glycoproteins and transialidases) have also been shown to be important targets of parasite specific humoral and cellular immune responses. They are, thus, important candidates for vaccine development as determined in studies using experimental models. Studies regarding the molecular cloning and/or biochemical characterization of the above mentioned T. cruzi surface molecules, and their ability to influence the outcome of T. cruzi infection in the vertebrate host through the stimulation and/or control of the immune system are presently reviewed. A proposition is made that such molecules may have evolved and been selectively conserved to establish an equilibrium between the parasite and its vertebrate host, limiting parasite replication, but allowing parasite persistence and host survival, thus favoring the maintenance of T. cruzi life cycle.

Carbohydrate epitopes: structure and presentation and the reactivity of biological ligands: recognition of alpha-D-Galp NAc and alpha-D-Galp conformational structures

Apart from glycolipids and glycoproteins that express A and B blood group antigens which contain terminal nonreducing units of alpha-D-Galp NAc and alpha-D-Galp respectively, there are several other glycoconjugates in nature that contain these units linked to unfucosylated saccharides or protein. They represent normal products of the action of specific glycosyl-transferases in primate and nonprimate mammalian cells, protozoa and a few other microorganisms, end-units of carbohydrate components that have not benn further processed by additional glycosylation, or neo-antigens resulting from deregulation of certain transferases as in tumor cells. Biological ligands recognizing these structures include mono and polyclonal antibodies, bacterial fimbriae and laminin. Binding depends on the linkages and sequence of the carbohydrate chain, but also on the epitope conformation as influenced by adjacent substitution, angling determined by the glycoconjugate-substrate interaction, steric hindrance and other factors. These aspects are discussed in this minireview.