1971 Volume 12 Issue 1 Pages 1-9
1. The postnatal changes of X-ray induced microcephaly were observed in sequence in CF # l mice which had been exposed to a single dose of 200R of X-ray from day 12 to 17 of gestation. 2. In the groups irradiated on day 12 and after day 14 of gestation, X-ray induced microcephaly remained unchanged or became less predominant as the animals grew older. In the group treated on day 13, the lateral ventricles of microcephalic brains started to enlarge one to two weeks after birth, and hydrocephalus became intensive progressively with the advance of age. Postnatal hydrocephalus was manifested in brains involved with marked aberration of cortical structure. 3. Prior to manifestation of hydrocephalus, venous congestion, hemorrhages and consequent tissue degeneration were evident in the subependymal white matter of neopallium. Neither stenosis nor obstruction in the ventricular system could be detected. 4. The results suggested possible causal relationships among maldevelopment of the cortical structure, circulatory disorders in the brain mantle and manifestation of hydrocephalus.