| Budget Amount *help |
¥2,000,000 (Direct Cost: ¥2,000,000)
Fiscal Year 1988: ¥800,000 (Direct Cost: ¥800,000)
Fiscal Year 1987: ¥1,200,000 (Direct Cost: ¥1,200,000)
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| Research Abstract |
Gamma rays were given to the lower half of the mouse body with the doses of 9, 11 and 13 Gy, and the recovery kinetics of the small intestinal epithelium were investigated. The radiation sensitivity of intestinal epithelial cells exhibited a marked circadian rhythm, showing that 0900 h should be the best time of day for separation and collection of radiation hypersensitive cells. The cell population which exhibit an acute death after radiations followed the circadian rhythm, while rhythm of crypt-forming cells (clonogenic cells) were easily influenced or disturbed by food and light conditions. Repeated injections of tritiated thymidine were carried out from 2.5 days to 4 days after 9 Gy, and 1, 2, 3 and 6 months later the autoradiographs of the small intestinal crypts were made. The silver grains were noted in several cells in crypts and this was also confirmed using the liquid scintillation counter. For the thymus, cells were separated and their sensitivity to gamma rays and protons were studied using the in vitro assay system. An electrophoresis of the homogenate of irradiated thymic cells showed protein bands specific to the cells irradiated. Crypt cells were also separated in vitro, and the similar experiments are now under way.
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