Morphometry of mitochondria in the choroidal ependyma of hydrocephalic guineapigs.

Fifteen young guineapigs were made hydrocephalic by intracisternal injection of kaolin and 16 guineapigs were used as control. Volume, number and surface areas of both the outer and inner membranes of the mitochondria of the choroidal ependyma of these animals were studied, using a coherent multipurpose test system. Volume, number and surface area of the outer membrane of the mitochondria did not show any significant difference between the two groups. However, surface area of the inner membrane of the mitochondria including cristae showed a significant decrease in the hydrocephalic animals. This reduction in the surface area could probably be attributed to the reduced activity of the choroidal ependymal cells in obstructive hydrocephalus.

The pineal recess of the opossum: a scanning and transmission electron microcospe study

Scanning and transmission electron microscope studies were performed in the pineal recess region of eighteen adult Didelphis albiventris opossums. With the scanning electron microscope, three concentric regions could be observed in the pineal recess: a central zone lined by cells free of cilia or microvilli, or by a meshwork of interdigitating cell processes; an intermediate zone lined by microvillous cells; and a peripheral zone, lined by ciliated cells. The transmission electron microscope revealed that the central zone is lined mainly by pinealocytes. The lining cells are frequently overlaid by a meshwork of pinealocytic and gliak oricesses. A <> (a meshwork of cellular processes underneath the lining cells) is contantly seen in the central zone. The intermediate zone is lined by elongated microvillous ependymal cells, and the peripheral zone by typical ependyma. The large liquor-contacting area in the pineal recess region, as well as the peculiar organization of its surface, suggest a complex interrelationship between the liquor and the pineal gland of the opossum

Correlative scanning and transmission electron microscopic study on the ependymal surface of cebus apella

Variaçöes topográficas da superfície ependimária de todo o sistema ventricular encefálico do Cebus apella, uma espécie silvestre brasileira, foram estudadas mediante microscopia eletrônica de varredura, após secagem pelo método do ponto crítico do CO2 e metalizaçäo pelo ouro-carbono. Determinadas áreas foram também estudadas no microscópio eletrônico de transmissäo, após os procedimentos técnicos usuais. Observamos distintos padröes na distribuiçäo de cílios, microvilosidades, e outras projeçöes celulares, além das assim chamadas estruturas supraependimárias. Säo feitas consideraçöes morfofuncionais, baseadas nos achados morfológicos