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Male BALB/c mice, 12 weeks old, were given a single exposure of either 137Cs gamma rays or d(50)-Be neutrons at a dose rate of 3 Gy/min. The animals were kept until death, and causes of death or possible causes of death were ascertained by autopsy and histology. The data were evaluated by competing risk methods. The survival time dose-effect curve for both types of exposure was linear and did not differ significantly (slopes: 55.8 +/- 4.0 days/Gy for neutrons and 46.2 +/- 4.3 days/Gy for gamma rays). The incidence of different diseases also was similar for both groups except that more carcinomas, sarcomas, and myeloid leukemias seemed to occur after neutron exposure and that nonstochastic lung and kidney diseases seemed to arise at lower doses.

The effectiveness of four anticonvulsants was tested in male CF1 mice exposed to 500-, 1000-, and 10,000-rad doses of mixed gamma-neutron radiations. Prevention of the hind leg extensor component of a maximal convulsion induced by electroshock was selected as the end point for effective anticonvulsant activity of diphenylhydantoin, phenobarbital, and mephenytoin. Prevention of convulsions induced by pentylenetetrazol was the end point of effective anticonvulsant activity of trimethadione. The effectiveness of the drugs was evaluated by comparing the ED50's to the ED50 value for unirradiated controls. The anticonvulsants tested by electroshock showed a tendency toward increasing effectiveness after 500- and 1000-rad doses of radiation and a significantly increased effectiveness following 10,000 rads. Trimethadione effectiveness in irradiated mice was similar to that in unirradiated controls at all doses and times tested.

The effect of 200, 1000, and 5000 rads of mixed gamma-neutron radiations on total blood reducing sugar and blood glucose levels in guinea pigs was investigated 2 and 24 hours, and 9, 22, and 60 days postirradiation. In addition, the effectiveness of insulin and tolbutamide in these animals was evaluated before and after irradiation. Glucose increased to a lesser degree and later than did the nonglucose fraction of the blood sugar. Insulin and tolbutamide were at least as effective in irradiated animals as in unirradiated ones except after 5000 rads, when tolbutamide was significantly less effective. These results suggest that: (1) insufficient insulin is released by the pancreas in response to elevated blood sugar levels following irradiation; (2) the pancreas does produce insulin at these times and is able to release it in response to tolbutamide; and (3) a decrease in insulin production occurs following supralethal doses of radiation.