Relative frequency of acentrics to dicentrics caused by radiation and by chemical action on human lymphocytes.

Various concentrations of sodium iothalamate were added to human blood samples before exposure to X-rays, in order to investigate the dependence of the frequency ratio of acentrics to dicentrics on treatment with radiation, the drug and a combination of the two. The results show that this ratio is markedly influenced by the relative action of the two agents, at low radiation dose, because of the enhancement of the acentric frequency caused by the chemical substance with respect to the spontaneous level. This paper presents the experimental yields of aberrations corresponding to the various treatments, and the calculated frequency ratios of acentrics to dicentrics as a function of X-ray dose, after correction for the physical effect of dose enhancement due to the presence of iodine in the drug.