Ultrastructural changes of basal laminae and protoplasmic astrocytes in craniostenosis with epilepsy.

Human brain biopsy specimens from twenty-four patients with epilepsy associated with craniostenosis and characterized by electroencephalography, were studied with an electron microscope. Characteristic ultrastructural changes were found in the basal lamina covering capillaries in the gray matter where the basal lamina was partially thickened, split and transformed into a heterogeneous network of strand enclosing electron-lucent areas. In the gray matter associated with epileptic convulsions, numerous filaments 60-100 nm in diameter appeared in protoplasmic astrocyte endfeet, apparently inserting in the plasma membrane adjacent to the basal lamina. Although the development of such filaments seemed to depend on precursor dense material appearing on the plasma membrane, their physiological function remains unknown. In cases with repeated epileptic convulsions, numerous fibrous astrocytes were seen in the affected portion of the gray matter, suggesting that they were the results of the repeated convulsions.