Paul S. Lavik

The differential effect of x-irradiation on the incorporation of various precursors into rat thymus deoxyribonucleic acid☆

Abstract A total body x-irradiation of 100 r. caused a 50% reduction in the incorporation of P 32 into rat thymus DNA, of orotic acid-C 14 into the DNA pyrimidines, and of formate-C 14 into the DNA guanine. However, the incorporation of adenine-C 14 into both DNA purines and of formate-C 14 into the DNA thymine and adenine was not significantly inhibited. Possible explanations for this differential effect of irradiation have been discussed.

Ineffectiveness of in vivo Dialysis in Prolonging Life in X-Irradiated Dogs.

Summary and Discussions Dogs given 500-550 r whole body x-irradiation were subjected to an in vivo dialysis of their blood during the early post-irradiation period. No improvement in the survival of these animals was noted. When applied 0.5-3.0 days after irradiation, the dialysis procedure caused a slight decrease in the average survival time, as compared to sham-dialyzed controls. The results tend to minimize the importance of readily dialyzable “toxins” in the lethal action of x-irradiation.