week. This is im contrast to other mammals where deaths frem the acute phees sre wecemmon after tie 30th day. 653 Prebabiiiey of Survival co Rela Symupeoms with little clinical evidence of jnjaries ot het than stight fatigue. Ac the termination of the latent period, the patient may develop purpura, epilation, oral and cutaneous lesions, infections of wounds or burns, diarrhea, and melons. The mortality will Hencn, individeale exposed in the lethal) be significamt. With therapy the survived time can be expected to be prelonged and feut several weeks following exposure) can be divided according te symptoms and signs, inte groups having a diferent prognosis. Thes they may be divided inte three groups in which survival is, reapectively, improdebls, peesidie, and predebic. It will be apparent that there is row regeneration the survival rate will be increased. In groups 1 and 2 the bleod picture is not as well documented as in group 3. There are goed clinical reasons to believe that im the lethal renge the granulocyte depressions will be range (where some, but not all, will die in the no sharp line of demarcation among the groups. if sufheient time ie provided for bone mar- marked and below 1,000 per man’ during the ad week, (jood observations in Japan (31, Group 1.—Swrrivel impredeble : If vomiting occurs promptly or within a few hours and continues and is followed in 22) confirm this contention. However, in the sublethal range it takes much longer for the death will almost cefinitely occur in 100 percent of the individuals within the 1st week. There is no known therapy for thease Hiroshima, the data of Kikuchi and Wakisaka rapid succession by prostration, diarrhea, anorexia, fever, the prognosis is grave; people; accordingly, in a catastrophe, at- tention shoald be devoted principally to others for whom there is some hope. Group 2.—arvtral poamble: Vomiting may occur early but will be of relatively short duration followed by a granulocyte count and platelet count of mea to reach minimal values, as compared to other mammals (see Chapter IV and reference 10). Despite the chaotic conditions that existed in (22) shows that there was a more rapid and marked decrease in Groups | and 2 than in (sroup 3. Group 3.—Surviral prodeble : This group consists of individuals who may or may not have had fleeting nausea and In this period of vomiting on the day of exposure. In this group there is no further evidence of ef- in the hemopoietic tissues. [Lymphocytes are profoundly depressed within hours and tologic changes that can be detected by and time of maximum depression depend- The Ivmphocvtes reach low levels early, within 4% hours, and may show little evi- period of well-being. well-being marked changes are taking place remain so for months. The neutrophile count is depressed to low levels, the degree ing upon the dose. Signs of infection may be seen when the total neutrophile count hax reached virtually zero (7-9 days). The platelet count may reach very low levels after 2 weeks. External evidence of bleed- Ing may occur within 2 of 4 weeks. This group represents the lethal dose range in the classical pharmacologic sense. In the higher exposure groups of this category the latent period lasts from 1 to 3 weeks te PR fecta of the exposure except the hema- serial studies of the blood with particular reference to lymphocytes and platelets. dence of recovery for many months after exposure. The granulocytes may show some depression during the second snd third week. However, considerable varia- A iate fail in the granulocytes during the 6th or (th week may occur and should be watched for. Platelet counts reach the lowest on approximately the %th day at the time when tion is encountered,

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