~6(7 - 9 days). ee The platelet ccunt may reach very low levels after two weeks, ternal evidence of bleeding may occur within two to four weeks, Ex- This group repre- sents the lethal dose range in the classical pharmacologic sense, In this group the symptom free period (the latent period) lasts from one to three weeks with little clinical evidence of injuries other than slight fatigue, At the termination of the latent period, the patient may develop purpura,* epilation oral end cutaneous lesions, infections of wounds or burns, diarrt:ea or melena**, significant. The mortality will be ith therapy the survival tine can be expected to be prolonged and if sufficient time is provided for bone marrow regeneration the survival rate will be increased, In group 1 (Survival impossible) and group 2 (Survival possible) the blood picture is not as well documerted as in group 3 (Survival probable). There are good clinical reasons to believe that in the lethal range the granulocyte depressions will be marked and below 1,000 per ma during the second week. in Japan confirm this contention. Cbservat’ons made However in the sublethal range it takes much longer for the granulocyte and vlatelet count of man to r each minimal values, as compared to other mammals, Despite the chaotic conditions that existed in Hiroshima the data of Kikuchi and Wakicaka (11) shows that there was a more rapid and marked decrease in groups 1 (Survival improbeble) and group 2 (Survival possible) than in group 3 (Survival probable). Before going on to group 3 survival probable, 1 cannot refrain from a comment on therapy. | Much has been learned from the experimental therapy of radiation injury in | enimals, It has been conclusively sown thet protection can be afforded by the transplantation of bone marrow from one strain of animal to another, The protection afforded by transplantation of genetically specific material, that is from one member of the same strain to an irradiated menber of the seme strain, is very good ard lonz lasting. If the waterial for treansplentation has its source in another strain of mouse, the protection is less marked and not as long lasting. * Blecding into shin ** Black stools from digested blood If the | IDOE ARCHr<

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