ae 7 = - = as oa values thereafter in the course of the study. The IYinjtiotyte cous fell Ca below control dewels inthe first few days, and remained at a level approximately 75 per cent of the controt value , throughout most of the remainder of (he observation pertod, In the Rongelap and Ailinginae groups the fluctuations in the total leukoevie count were ae counted for almost entirely by changes in the total neutrophule count. The Ronperik proup du fered since the changes total teukocyte count were reflected almost equally ia the lympho cyte and neutrophilte count, The significance of this difference in response in the (wo groups is hot apparent, . The platelet_counts (Fig. 4.6) were not markedly depressed when the initial counts were taken duping the third week, At the end of the third weck, however, the platelet count began to fall to reach a low of approximately 60 per cent of control levels at the end of the fourth week. The value then returned to approximately the control level at the start of the seventh week, " be i following which a second depression was noted. The platelet counts were at a level of 80 per. i cent of the control value at the time of the last observation during the eighth post-exposure t . i week. MONOCYTES AND EOSINOPHILES, ALL GROUPS From Table 4.2 it is seen that the mean monocyte count for the Rongelap group rose abruptly from an early value below control levels to a well defined peak on day 12, following which it fluctuated at values below the control level for the duration of the observation period. A similar time trend was noted in the Ailinginae and Utirik groups. The eosinophile count in the older age individuals, Rongelap group, rose from very low levels abserved on day 3 to values approximating 35 per cent of control during the second week, where it remained from the third to the fifth week (Fig. 4.7). The counts then decreased (P < 0.01), and remained at a value approximately 15 per cent 07 control throughout the re- wen ve 4.9 i t mainder of the study. The time trend of response was similar in the younger age individuals, however, changes in the younger age group were relatively greaterif considered in terms of the control values. Similar trends in eosinophile count were not evident in other exposure wt groups. _— It is possible that the rise in eosi ‘g represents that reported as occurring “... two to three weeks after short-wave-lengt. uation”. “ 4.10 HEMATOCRIT, ALL GROUPS The hematocrit values for all exposed groups are shown in Table 4.8 and in Fig. 4.8 (a detailed breakdown of hematocrit by age and sex for control groups is given in Table 4.1). When hematocrits were first done on the 22nd day, mean valves for the Rongelap and Ailinginae froups were below those of the control population. A significant trend in values after this time could not be detected statistically. 4.11 MORPHOLOGY OF PERIPHERAL BLOOD Significant morphologicai cellular changes, with the exception of a small number of abnormal mononuclear cells* seen in a number of individuals during the period of neutropenia, were not observed. Similarly altered cells have been observed previously.Complete evaluation of these changes in the present study would necessitate an exhaustive serial study of the hematology slides. *There was considerable difference in opinion in respect to classification of these cells. They were classified as atypical monocytes, degenerating lymphocytes, atypical myelocytes, monocytoid lymphocytes, and lymphocytes in transition to myelocytes. At the time of this report there was no unanimity of opinion in respect to classification and significance of these cells. 81 j ,