Abstract
1. The experiment was designed to examine the vascularity of the brain mantle of X-ray induced microcephaly in mice, in order to elucidate the pathogenesis of circulatory disorders which occurred postnatally and would play an important role for the manifestation of hydrocephalus. 2. CF # I female mice were exposed to a single whole-body X-radiation at a dose of 200R on day 13 or 15 of pregnancy. The brains of the offspring were examined in vascular specimens with india ink injection and histological sections stained with H. E. or gallocyanine. 3. Abnormal vascular pattern and poor vascular network of the neopallium were demonstrated to exist in the microcephalic brains with aberrant cortical structure. A distinct correlation both in degree and in site between the abnormal vascular pattern and the histological aberration of the cortical structure was found. The results suggest a causal relationship between prenatal abnormal vascular formation in the brain mantle and cerebral venous congestion with hemorrhage manifested postnatally. The authors wish to thank Dr. Kyoji Kondo, Professor of the Department of Animal Breeding, Faculty of Agriculture, Nagoya University, for his instructions in X-ray ad-ministration. The authors also acknowledge the technical assistance of Mr. Osamu Fujii, Research Institute of Environmental Medicine, Nagoya University.
