RESUMEN
Extracts from the cervical spinal cord and from the medulla, thalamus, cerebellum and cerebral cortex of the brains of 10 sheep, histopathologically confirmed as cases of scrapie, were examined by electron microscopy for the presence of scrapie-associated fibrils. Characteristic fibrils were observed in all the extracts except for that from the thalamus of one sheep. No fibrils were found in any extracts from three control sheep. A comparison of these results with a similar study of 22 cases of bovine spongiform encephalopathy (BSE) suggests that in cases of scrapie the area of the brain chosen for the detection of fibrils is less critical than in cases of BSE, in which fibrils are more readily extracted from areas of the brain stem.
Asunto(s)
Encéfalo/microbiología , Priones/aislamiento & purificación , Scrapie/microbiología , Médula Espinal/microbiología , Animales , Cerebelo/microbiología , Corteza Cerebral/microbiología , Bulbo Raquídeo/microbiología , Microscopía Electrónica , Priones/ultraestructura , Ovinos , Tálamo/microbiologíaRESUMEN
In previous studies we found an increase in body weight during the preclinical phase of disease in certain scrapie strain-mouse strain combinations. The effect was augmented by injection into the hypothalamus. In the present study, we found an increase in food consumption (compared to the normal mouse brain injection group) for both the 139A and ME7 scrapie groups, although only the ME7 group showed an increase in body weight. In a scrapie strain-mouse strain combination that showed an increase in body weight, the adrenal gland was the only organ that showed a significant increase in weight. The titer of scrapie in the adrenals was comparatively low. Adrenalectomy prevented the increase in body weight in two strains of mice injected with the ME7 scrapie strain. The results suggest that scrapie-induced obesity depends on an effect of scrapie on the hypothalamic-pituitary-adrenal axis.