1984年 · 第04卷第06期

A total of 138 dogs succumbing to whole body exposure of 5.1~202.7 Gy of mixed gamma and neutron irradiations were classified as dead of cerebral (12 cases), tgastrointestinal (103 cases) and haematopoietic deaths (23 cases). There were four types of changes in small intestine mucosa: necrosis, denudation, regeneration and almost restoration. Within 2 days after irradiation, the changes of intestinal mucosa in all animals were of necrotic type, but 3~5 days after irradiation the changes varied with the different types of radiation sickness. In dogs dead of haematopietic death the intestinal epithelium had already regenerated and restorated, with the characteristics of their small intestinal mucosa free of denudation. In all dogs dead of gastrointestinal death, the intestinal epithelia showed denudation, and early regeneration appeared in 53.7 per cent of them. In the case of cerebral death, all dogs died within 2 days after irradiation.

The authors proposed a criterion for diagnosing gastrointestinal radiation sickness pathologically.

Chromosome aberrations in cultured peripheral blood lymphocytes of 20 persons accidentally exposed to γ-rays from a 1.46Ci ¹³⁷Cs source were investigated. As a result of the radiation exposure lasting 33.5 days, their average absorbed doses to bone marrow were estimated to be equivalent to 1.2~53 rad. Samples of peripheral blood for chromosome analysis were obtained in the 2nd week, the 3rd month and one year after the end of exposure. In general, frequencies of chromosome aberrations in exposed cases were higher than those in controls, but it seems that the frequency of cells with chromosome aberrations increased with increasing dose in the 2nd week after the end of exposure.

Among the types of chromosome aberrations, acentric abnormalities were predominant in the 3rd month and one year after the end of exposure. One case who received 36 and 620 rad for bone marrow and partial body respectively showed the highest frequency of dicentric plus ring type which was decreasing as time went on.