Conarp Effects of Ionizing Radiations 494 25 § 5 Control baseline 0o'-—_—_—" wa Bos $ 5 “50+ 5 a J White blood cells (average counts } Platelets (average counts ) -75 — 25507 6 Days | 2 Mo*— 1 = 4 6 8 10 12 4 Years Fig, 3 crease in flecks in the lens of females exposed during adolescence [9]. These data also suggested that variation of sex hormones might play a role in radiosensitivity of thelens. Chromosome aberrations. Evidence for persisting damage to the genetic apparatus ofthe cell in the form of chromosomeaberrations in lymphocytes of peripheral blood cultures has been noted in several irradiated populations (laboratory accident cases [3], Marshallese [22], Japanese fishermen [21] and the Japanese exposed at Hiroshima and Nagasaki [4]). The incidence was low but the aberrations were noted as late as 20 years after exposure in the Japanese. Such chromosome changes have also been noted in cultured thyroid cells years after radiation therapy [15], and are no doubt present in other cells of an irradiated individual. Such findings lend support to the so- matic mutational theory of aging. Immunohematological changes. There are certain findings in exposed Rongelap people indicating reduced immunological potential. Based on peripheral blood counts, recovery from the acute depression of white bloodcells and platelets which was noted during the first 6 weeks after exposure was nearly complete by 1 year but continued to fluctuate at a level slightly below the unexposed populations in subsequent years (see fig. 3). However, it is not certain that such peripheral blood counts reflect bone marrow injury. During the past few years we have carried out certain immunohematological tests on the Marshallese and found that the exposed people haveincreasedalbumin levels and significant reduction in y-globulin levels (about 17 % below 4, f ir fl: F wipes Bree Reo ce8 peor 3 b s x b