Accession Number : AD0647224

Title :   RECOVERY FROM RADIATION INJURY IN THE HAMSTER AS EVALUATED BY THE SPLIT-DOSE TECHNIQUE.

Corporate Author : NAVAL RADIOLOGICAL DEFENSE LAB SAN FRANCISCO CALIF

Personal Author(s) : Holloway,R. J. ; Leong,G. F. ; Ainsworth,E. J. ; Albright,M. L. ; Baum,S. J.

Report Date : 20 DEC 1966

Pagination or Media Count : 38

Abstract : The split-dose technique was used to determine the pattern of recovery from radiation injury in the Syrian hamster (Mesocricetus auratus). Exposure of the animals to 1 Mvp X-rays resulted in a LD50/30 of 941 R (95% confidence interval: 917-967 R). Recovery, defined as a return to normal radiosensitivity after a sublethal exposure, was found to be non-exponential; in fact, a marked transient increase in radiosensitivity was observed during the second week. After exposure to 2/3 LD50/30, relatively little recovery was observed on the 3rd day after the conditioning exposure; 94% of the initial injury remained. Between the 3rd and 7th day the hamster recovered at a rapid rate; only 26% of the initial injury remained on day 7. These periods of recovery were followed by a regression of the animals to a more radiosensitive state; 76% of the initial injury was present on day 11. After this time, the animals returned toward more nearly normal radiosensitivity; 20% of the initial injury remained at day 20. These findings are a marked deviation from the exponential recovery pattern usually reported for other rodents. Hematological studies indicate that the extent of recovery, in terms of split-dose radiosensitivity, is not correlated with the number of circulating erythrocytes, thrombocytes, granulocytes, or mononuclear cells. (Author)

Descriptors :   (*RADIATION INJURIES, RECOVERY), HAMSTERS, HEALING, X RAYS, RADIATION DOSAGE, SUBLETHAL DOSAGE, EXPOSURE(PHYSIOLOGY), HEMATOLOGY

Subject Categories : Radiobiology

Distribution Statement : APPROVED FOR PUBLIC RELEASE