An ultrastructural study of a biopsy fragment from the cerebellar cortex of a patient with ataxia-telangiectasia was performed. There was a sharp reduction in the number of Purkinje cells and an increase in the number of Golgi epithelial cells. Despite the degeneration of Purkinje cell dendrites, the volumetric density of parallel fiber varicosities and the number of synapses in the molecular layer were only slightly reduced. No qualitative nor quantitative abnormalities were noted in the granular layer. An analysis is made of the severe changes in cerebellar circuitry of this patient and their probable functional implications.

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Several experimental brain oedema models are currently available, but most of them are very different from what happens in clinical practice. As it is simple and seems to replicate the range of injuries seen in man we decided to evaluate Marmarou's model of head injury in order to test physiopathogenic and therapeutic hypotheses. Three groups of Wistar rats weighting 360-400 gr, anaesthetized with sodium pentobarbitone and breathing spontaneously, without tracheal intubation, were studied. In the first group six animals were killed two hours after injury and the brain's water content compared with that of nine controls. In another group Evans blue (100 mg/kg) was injected one hour before trauma and dye's extraction ratio determined at various times after injury: five animals at 15 minutes, six at 30 minutes, five at 60 minutes and nine at 120 minutes. A total of twenty-eight animals served as controls. In the last group morphological studies with light and electron microscopy were performed in the traumatized brain tissue from rats killed 5 and 120 minutes after injury and in brain tissue from control rats. Results showed that Marmarou's brain trauma model induced perivascular brain oedema, already visible at the ultrastructural level 5 minutes after the injury. Endothelial cells themselves were "oedematiated", rich in pinocytotic vesicles and membrane blebs, and presented intact tight junctions. Two hours after trauma the perivascular oedema was more marked. At this time the brain water content was significantly higher than that in controls. Evans blue extraction ratio increased linearly with time, being significantly higher than in controls 120 minutes after injury. We conclude that Marmarou's model is a suitable model for the study of brain oedema induced by trauma, and that this oedema, assessed by three different methodologies, was statistically significant two hours after injury.

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Evidence indicating cell membrane fusion among cells and their processes where subacute sclerosing panencephalitis (SSPE) virus is present is shown in an ultrastructural study of a brain biopsy. Virus budding from plasma membrane was not seen. These rare findings reinforce the hypothesis of cell-to-cell transmission as the most likely mechanism of SSPE virus infection. The presence of fused membranes between cell processes and cell soma probably explains the rapid spread of this virus throughout the nervous system.

RESUMO:Este estudo avaliou o efeito de um programa de exercício físico -caminhada -em pessoas idosas saudáveis, previamente sedentárias, na flexibilidade. Um programa de treinamento físico de baixa a moderada intensidade foi desenvolvido e testado. Foi estabelecido parâmetro clínico para classificar e avaliar a evolução da flexibilidade. O estudo foi realizado com 20 pessoas (10 em grupo experimental -A, e 10 em grupo de controle -B) com idade média 68,6 anos, ativos nas comunidades e livres de distúrbios ou doenças cardiovasculares, pulmonares, neurológicas ou musculares, ou ainda de doenças crônicas que poderiam afetar a habilidade para praticar exercícios. O treinamento ocorreu durante quatro meses, em sessões de uma hora, duas vezes por semana, alcançando 40% a 70% de freqüência cardíaca máxima calculada. Ao término do quarto mês, avaliou-se novamente a flexibilidade (pós-teste). O treinamento produziu melhora clínica e estatística para flexibilidade. DESCRITORES: Atividade física. Envelhecimento. Exercício. Idoso. Sistema músculo-esquelético. Caminhada.

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