Accession Number : AD0671054

Title :   EARLY ALVEOLAR CELL MITOTIC ACTIVITY AND PULMONARY TUMOR INCIDENCE IN URETHAN TREATED X-IRRADIATED MICE,

Corporate Author : NAVAL RADIOLOGICAL DEFENSE LAB SAN FRANCISCO CALIF

Personal Author(s) : Birdwell,Thomas R. ; Cole,Leonard J.

Report Date : 12 APR 1968

Pagination or Media Count : 17

Abstract : Groups of young adult LAF1 mice received a single intraperitoneal injection of urethan (1 mg/g body weight) given either alone, before (1 or 7 days) or after (7 days) a 300 R whole body dose of X radiation. The effects of these treatments on alveolar cell mitotic activity during the subsequent 15 days, and on pulmonary tumor incidence at 13 to 24 weeks were determined. The mice receiving urethan only, all showed lung tumors at 24 weeks. The groups irradiated prior to or after urethan injection showed significant decreases in the number of tumors per mouse, as well as a decrease in mitotic activity 15 days posttreatment. The suppression in both these parameters was more pronounced when X radiation preceded urethan treatment by 1 week, than when it was administrated 1 week after urethan. The results indicate that at this moderate dose of X radiation (300 R) there is an inhibitory effect on urethan lung tumorigenesis. It is suggested that X irradiated alveolar cells under these experimental conditions are relatively resistant to the effects of urethan, as reflected both in mitotic activity, and in subsequent tumor production. The theoretical bases for these observations on lung tumorigenesis are briefly discussed. (Author)

Descriptors :   (*CANCER, *LUNG), (*RADIATION EFFECTS, NEOPLASMS), MITOSIS, X RAYS, RADIATION DOSAGE, INHIBITION

Subject Categories : Radiobiology

Distribution Statement : APPROVED FOR PUBLIC RELEASE