Hypoxic-ischemic brain lesions found in asphyxiating neonates.

Early hypoxic-ischemic brain lesions were examined regarding 26 autopsy cases which had severe asphyxia at birth and died within the first week. All cases were divided into three groups according to the birth weight: group A of less than 1,000 grams, group B of 1,001-2,500 grams, and group C of more than 2,501 grams. Neocortical and deep gray matter revealed pyknotic and karyorrhectic neuronal changes; however, in group A, these changes tended to be obscure. The hippocampus was the predictive site of the neuronal changes such as pyknotic neurons in Sommer's sector and karyorrhectic neurons in subiculum. In 12 cases, pontosubicular-type necrosis was found. White matter lesions were relatively characteristic and there was an early appearance of pathological astrocytes such as gemistocytic, Alzheimer-type 2 and stellate astrocytes, periventricular leukomalacia with or without hemorrhage. The brain stem and cerebellar lesions were also found occasionally revealing neuronal or glial changes. We applied the immunoperoxidase method using antisera to glial fibrillary acidic protein (GFAP) and S-100 protein for determination of pathological astrocytes. GFAP was a useful marker for pathological astrocytes in the subpial region and in the white matter. S-100 protein was present in Bergmann's glia and satellite glia as well as pathological astrocytes.