In Vitro and in Situ Action of Ionizing Radiations on Nucleoproteins of the Cell Nucleus

The reason for studying the action of ionizing radiations on chromosome constituents is to find out something of the fundamental phenomena occurring during the production of biological and morphological anomalies by radiations (i.e., lethal effects, mutations and breakages or translocation of chromosomes). These biological and morphological effects have been extensively studied and a relationship between dosage and the effects produced has been observed. The interpretation of these findings has led certain authors to postulate a direct effect of these radiations; thus a single ionization would suffice to cause a mutation, a single ionizing particle would be capable of breaking a chromosome. The criteria of such direct action of radiations have been clearly expressed by Lea (1946). It is therefore of interest to observe some molecular components, which, when submitted to these radiations in a state similar to that in which they exist in the living cell, will serve as a...