Analysis of radiation injuries of DNA from liver and transplanted tumors in vitro

A comparative study of some radiation effects on DNAs from mouse liver, Ehrlich ascites tumor and hepatoma 22A was made after X-irradiation of the 0.02% aerated solutions in 0.1 M NaCl. The electrophoretic and spectrophotometric methods were used to measure the radiation-chemical yields of single- and double-strand breaks, DNA secondary structure defects, a malonaldehyde analogue and pyrimidine hydroperoxides. DNA from tumors was found to be more affected by radiation than DNA from normal liver: this may be due to a higher degree of base damage (the yield of hydroperoxides) and to transformation of original secondary structure defects into single-strand breaks at low irradiation doses.