Comparative study on Tp53 gene mutations in lung tumors from rats exposed to 239Pu, 237Np and 222Rn.

The tumor suppressor gene Tp53 was analyzed by polymerase chain reaction-amplification of genomic DNA extracted from paraffin-embedded tissue sections of rat lung tumors to compare mutations that occurred after inhalation exposures to plutonium dioxide, neptunium dioxide, or radon and radon progenies. Exons 5 to 8 of the gene were amplified in 16 plutonium-, 23 neptunium- and 15 radon-induced lung tumors, and their polymerase chain reaction products were examined for mutations by single strand conformational polymorphism analysis and direct sequencing method. Two point mutations were detected in the plutonium-induced tumors, i.

Influence of exposure rate on radon-induced lung cancer in rats.

A new series of experiments was carried out to investigate specifically the influence of exposure rate on lung cancer induction in rats at relatively low cumulative exposures of about 100 WLM, and at potential alpha energy concentrations (PAECs) ranging from 13 to 150 WL. The results indicate that at relatively low cumulative exposures comparable to lifetime exposures in high-radon houses or current underground mining exposures, the risk of lung cancer in rats decreases with decreasing PAECs, i.e.