Prediction of interindividual differences in radiosensitivity in mammals.
Prediction of individual radiosensitivity of mammals is of interest to radiobiology on the one hand and it is also important to the clinical use of radiation. The author has reported that there is a relationship between radiosensitivity in individual animals and its homeostatic activity that allows predicting individual radiosensitivity. In the present report, a phenomenon of metabolism was used to measure the homeostatic activity of an individual mouse DBA strain, 90 days old; that is, the metabolic rate was calculated from daily diet or water consumption, and body weight. Each mouse fasted completely for one day and the ratio between metabolic rates just before and just after the fast (value after fast/value before fast) was calculated to use as the index of homeostatic activity of each mouse. One week after fasting, the mice were exposed to X-rays of 500 R and the ratio of metabolic rates just before and just after exposure was calculated again. Ten days after exposure the mice were sacrificed and the spleens were fixed in Bouin's solution. After fixing, the splenic weight was measured and an endogenous spleen colony count (more than 1 mm diameter) was made, which was one response to radiation damage to the hematopoietic system. The results, summarized from several repeated experiments are given in the table below: [table: see text].
Kyoto University, Kyoto, Japan.
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Y
Ueno
D000818:Animals; D001481:Basal Metabolism / Q000502:physiology* / Q000528:radiation effects*; D004307:Dose-Response Relationship, Radiation; D005260:Female; D006413:Hematopoietic System / Q000528:radiation effects*; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D008811:Mice, Inbred DBA; D009929:Organ Size; D011829:Radiation Dosage; D011833:Radiation Injuries, Experimental; D011836:Radiation Tolerance / Q000235:genetics / Q000502:physiology*; D013154:Spleen / Q000528:radiation effects*