Further efforts to influence x-ray cataract by chemical agents.

Abstract

ACCORDING to the target theory, significant radiobiological effects are produced solely by direct hits of single ionizing particles upon sensitive parts of irradiated cells. During the past 10 years, however, studies on the effect of x-rays on aqueous solutions of various chemical substances have indicated that indirect biochemical mechanisms mediate at least some of the actions of ionizing radiations. Of these biochemical processes, the production of active radicals by the ionization of water is best understood and is believed to be of first importance, although such other possibilities as the shifting of the redox potential of critical areas and the depression of metabolic processes by irradiation have been suggested. In vitro investigations on solutions of highly polymerized desoxyribonucleic acid 1 and on sulfhydryl enzymes 2 have shown clearly that the effectiveness of the radiation is decreased in the presence of other solutes, i. e., that chemical agents can protect irradiated