A associação estável a macromoléculas e a flexibilidade da esfera de coordenação são propriedades intrínsecas do zinco e sua essencialidade encontra-se intimamente relacionada ao seu papel biológico, seja na ativação da função catalítica de enzimas, seja na estabilização das estruturas conformacionais de proteínas e ácidos nucléicos. O zinco é o segundo elemento traço essencial mais abundante no organismo humano e é necessário à atividade de mais de 300 enzimas dos 6 tipos de classes existentes. Estas características tornaram o metal e seus ligantes fontes de grande interesse para a nutrição experimental, já que o seu estudo converge para a determinação da biodisponibilidade do metal. Dentre esses ligantes, a isoforma testicular da Enzima Conversora de Angiotensina, sintetizada pelas células germinais masculinas, pode ser considerada um exemplo marcante de regulação molecular a partir da ligação do zinco, influenciando tanto a atividade quanto a concentração desta enzima e conseqüentemente a função testicular.Termos de Indexação: zinco, enzima conversora de angiotensina, disponibilidade biológica, função testicular, enzimas.
The effect of diets enriched with fat containing different fatty acids on the activity and expression of the glucose‐6‐phosphate dehydrogenase (EC 1.1.1.49) of mesenteric lymph nodes, lymphocytes and intraperitoneal macrophages was examined. Measurements of the enzyme were also performed using spleen, thymus and liver for comparison. The following fat rich diets containing a variety of fatty acids were used: 1‐standard chow (CC); 2‐medium chain saturated fatty acids (MS)‐cocconut fat‐oil; 3‐long chain saturated fatty acids (LS)‐cocoa butter; 4‐monounsaturated fatty acids (MU)‐canota oil (n‐9); 5‐polyunsaturated fatty acids (PU)‐soybean oil (n‐6). Of the fat‐rich diets tested, MS had the least effect. The G6PDH activity of lymphocytes was reduced by all the fat‐rich diets; 16% for MS, 38% for LS, and 54% for MU. Similarly, the enzyme activity was reduced in macrophages; 35%, 86%, and 73%, for LS, MU, and PU. respectively. In contrast, the fat‐rich diets elevated G6PDH activity in the lymphoid organs; by 42% in the spleen due to LS and by 131%, 35%, and 56% in the thymus due to LS, MU, and PU, respectively. Fat‐rich diets decreased the activity of G6PDH in liver: 42%, 68%, and 39% for MS, MU, and PU, respectively. Some of the changes in G6PDH activity induced by the fat‐rich diets occur through the mechanisms of mRNA abundance.
-We report four Brazilian siblings with Autosomal Dominant Hereditary Motor Sensory Neuropathy with Proximal Dominant Involvement (HMSN-P), a rare form of HMSN, that was characterized by proximal dominant muscle weakness and atrophy onset after the age of 30 years, fasciculation, arreflexia and sensory disturbances with autosomal dominant inheritance. Electrophysiological study and sural nerve biopsy were in the accordance with axonal sensory motor polyneuropathy and laboratorial analysis disclosed serum lipids and muscle enzymes abnormalities. Our report is the first done by a group outside Japan, where the disease initially seemed to be restricted and stressed the phenotypic variability from the original report.KEY WORDS: HMSN, HMSN-P, proximal motor neuropathy, axonal neuropathy, proximal muscle atrophy.
HMSN autossômica dominante com envolvimento proximal: novos casos brasileirosResumo -Relatamos os casos de quatro irmãos brasileiros com Neuropatia Sensitivo Motora Hereditária com Envolvimento Proximal Dominante (HMSN-P), uma forma rara de HMSN caracterizada por fraqueza muscular de predomínio proximal e atrofia de instalação após os 30 anos, fasciculações, arreflexia, distúrbios sensitivos e padrão de herança autossômica dominante. Os estudos eletrofisiológicos e de biópsia do nervo sural confirmaram o diagnóstico de polineuropatia sensitivo-motora com padrão lesional axonal. Laboratorialmente foram constatadas anormalidades séricas no metabolismo lipídico e enzimas musculares. Nosso relato é o primeiro feito por um grupo fora do Japão, onde a doença parecia restrita até então e ressalta a variabilidade fenotípica apresentada nos casos Brasileiros. PALAVRAS-CHAVE: HMSN, HMSN-P, neuropatia motora proximal, neuropatia axonal, atrofia muscular proximal.
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