Hematological E T. KUMATORI 68 subjects, i.e. Hiroshima cases, cidents (Hempetman et al., 1952 ; and Marinecur, 1956; Gusxova Jamvet, 1961), it is noted that Marshallese, and cases exposed by reactor acAmano, 1953 ; Cronkite et al., 1956 ; HasTERLIs and Barisocotov, 1956; Anprews et al, 1961 ; all these cases similarly revealed the minimal value at about one monthafter exposure. od 5. Bone Marrow The bone marrow was aplastic at the critical stage in severe cases, which showed remaining and proliferation of plasma cells and reticulum cells. Figure 3 shows the bone marrowof oneof the severe cases. Comparing with normal - ¢ > . - ’ z ‘- ~F 3 ng a re oe we : « . . »? ° ‘aoe . . nn . > 2 . ?7 a“ #1? ~ 2 oo \ os - 7? 1 . 2 ME otpst 7 - a oe. ~ - - we. . - rut af ¢ im ee tha. ‘tet * ”*% . Sam ue”. . g one . a uy wee ete em ae Fig. 3 of Biki ative) Vy (cumul "ss ae. ~~ ar. oS See fe 340 « ey dy sn os oe ee -e ete Te o w!? cor Pid ~ r’ oo a. oe” . a 8 , - * ood . 2 . -o3 se, » , , . Leukocytes ~* a oo we fFeeHn, Fig. 4 ~ ate « = te . ao * hen, ew . Z - 7? ‘ant . “aa, A - —_— * we pe at ‘ “ ‘ e+ ' - ae Bone marrowof one of severe cases at 5th week. bone marrow a lack of bone marrow cells was observed. With the beginning of recovery, aplastic marrow changed to hypoplastic and then turned into a type of maturation arrest. In some cases, recovery was not complete In less severe cases, the bone marrow was not aplastic Several morphological abnormalities were observed: nuclear debris of lymphocytes, binucleated lymphocytes, vacuoles of neutrophils, toxic granulations of neutrophils, degenerative changes of bloodcells, mitotic abnormalities of erythroblasts, ete. Motility and phagocytosis of neutrophils decreased remarkably. After one year, in some cases these functions were still lower than in normal persons. FOLLOW-UP STUDIES As above mentioned 16 to 18 fishermen have been examined on an annual basis. Figure 4 shows the changes of the cumulative distribution curves of leuko- int '" Fig. 3 Changes ar table btm Morphological and Functional Changes oytes neutrophils scbyge.y* albeciowiurnntiee | anor eR but hypoplastic or in a type of maturation arrest even at the critical stage. 6. am even after one year. cvtes. The curve of critical stage appeared clisplaced far to the left of the normal curve. and gradually approached normal values. of normal Japan the curve 4ppr in the curoulatis However ! the changes of are representat A small ia of erythroblas 10 yeats- Cytogene results are SU 1. The fetta However, the curve of the 6th year wasstill displaced slightly to the left