PATHOLOGICAL CHANGES IN NEURONS, NEUROGLIA, AND BLOOD-BRAIN BARRIER INDUCED BY X-IRRADIATION OF HEADS OF MONKEYS

Abstract

IN COMPARISON with the severe changes seen in many tissues, reports concerning the effects of ionizing radiation on the adult central nervous system have usually indicated a relative radioresistance on the part of the brain.^*This observation is supported by experiments suggesting that sensitivity to irradiation depends in part on the rate of synthesis of nucleic acids, the lymphocyte and the maturing neuroblast appearing more radiosensitive than the adult neuron.⁵Despite these general statements, reports from both clinical † and experimental sources ‡ reveal that irradiation can produce extensive neuronal pathology and overt neurological disorders. Of key interest here has been the question of the relative importance of direct and indirect neuronal injury: direct by primary alteration of nerve cells, and indirect from changes secondary to alterations in neuroglia or the blood-brain barrier. In this connection, primary impairment of neurons, of neuroglia, and of the vascular system has each