Maple syrup urine disease (MSUD), or branched-chain α-keto aciduria, is an inherited disorder that is caused by a deficiency in branched-chain α-keto acid dehydrogenase complex (BCKAD) activity. Blockade of this pathway leads to the accumulation of the branched-chain amino acids (BCAAs), leucine, isoleucine, and valine, and their respective ketoacids in tissues. The main clinical symptoms presented by MSUD patients include ketoacidosis, hypoglycemia, opisthotonos, poor feeding, apnea, ataxia, convulsions, coma, psychomotor delay, and mental retardation. Although increasing evidence indicates that oxidative stress is involved in the pathophysiology of this disease, the mechanisms of the brain damage caused by this disorder remain poorly understood. In the present study, we investigated the effect of BCAAs on some oxidative stress parameters and evaluated the efficacy of L-carnitine (L-car), an efficient antioxidant that may be involved in the reduction of oxidative damage observed in some inherited neurometabolic diseases, against these possible pro-oxidant effects of a chronic MSUD model in the cerebral cortex and cerebellum of rats. Our results showed that chronic BCAA administration was able to promote both lipid and protein oxidation, impair brain antioxidant defenses, and increase reactive species production, particularly in the cerebral cortex, and that L-car was able to prevent these effects. Taken together, the present data indicate that chronic BCAA administration significantly increased oxidative damage in the brains of rats subjected to a chronic model of MSUD and that L-car may be an efficient antioxidant in this disorder.
Recently, the consequences of diabetes on the central nervous system (CNS) have received great attention. However, the mechanisms by which hyperglycemia affects the central nervous system remain poorly understood. In addition, recent studies have shown that hyperglycemia induces oxidative damage in the adult rat brain. In this regard, no study has assessed oxidative stress as a possible mechanism that affects the brain normal function in neonatal hyperglycemic rats. Thus, the present study aimed to investigate whether neonatal hyperglycemia elicits oxidative stress in the brain of neonate rats subjected to a streptozotocin-induced neonatal hyperglycemia model (5-day-old rats). The activities of glucose-6-phosphate-dehydrogenase (G6PD), 6-phosphogluconate-dehydrogenase (6-PGD), NADPH oxidase (Nox), superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GSHPx), the production of superoxide anion, the thiobarbituric acid-reactive substances (TBA-RS), and the protein carbonyl content were measured. Neonatal hyperglycemic rats presented increased activities of G6PD, 6PGD, and Nox, which altogether may be responsible for the enhanced production of superoxide radical anion that was observed. The enhanced antioxidant enzyme activities (SOD, CAT, and GSHPx) that were observed in neonatal hyperglycemic rats, which may be caused by a rebound effect of oxidative stress, were not able to hinder the observed lipid peroxidation (TBA-RS) and protein damage in the brain. Consequently, these results suggest that oxidative stress could represent a mechanism that explains the harmful effects of neonatal hyperglycemia on the CNS.
Objetivo: Este estudo avaliou a concordância de fontes de informação, em nível nacional e internacional, que orientam a prescrição pediátrica de antimicrobianos para faringotonsilite, otite média aguda e rinossinusite, em relação ao fármaco de escolha, à posologia e aos tipos de referências utilizadas para sua elaboração. Método: Foram selecionados documentos de entidades brasileiras e estrangeiras e as bulas dos medicamentos neles mencionados, totalizando 14 documentos diferentes para as doenças avaliadas. Resultados: A classe das penicilinas foi prevalente como terapia de primeira escolha nas três doenças estudadas, contudo houve grande variação nas doses indicadas e no modo como elas são expressas. A idade mínima para uso foi informada em 54,3% das fontes, sendo menos recorrente nas fontes nacionais. A duração do tratamento esteve presente em 64,4% dos fármacos indicados nas fontes. As fontes analisadas para as três doenças avaliadas citam principalmente referências classificadas como artigos de revisão e estudos experimentais, seguidos dos formulários e listas oficiais e consensos, diretrizes e manuais para embasar seus dados. Conclusão: Os resultados encontrados reforçam a necessidade de estimular a realização de ensaios clínicos e/ou estudos de Farmacometria para a definição de doses de antimicrobianos para uso em Pediatria, assim como a harmonização das informações disponibilizadas para orientar a prescrição
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