studied in persons exposed to ionizing radiat well as to a variety of exogenous agents such cyclamates, caffeine, and LSD. More recently effects of elements such as cadmium that are vironmental pollutants suspected of contribut to human disease ?® have been studied. Radiat induced human chromosome aberration yields ha been used to estimate radiation doses receive: - people involved in radiation accidents involv whole-body exposure to 60,19 Similar studi: also been performed on peripheral blood leuco obtained from subjects exposed years ago to TI 20,21 232 trast; the element Th decays through 6 alpha and 4 beta disintegrations to 2085, (i 90 percent of the radiation energy is associat Fig. 10. Autoradiograph of lung section of subject No. 2 showing a radioactive particle. with high LET alpha rays). Radium daughter pr ucts deposit in bone, thoron is exhaled, and c sequently both bone and lung tissue are irradi in the liver of human subjects, we can make no Finally, the chromosomes of blood lymphocytes quantitative statements concerning the observations patients with body burdens of radium have been in several persons who were measured. analyzed; many of these patients were exposed Plutonium within the bone cannot be measured by the tm vivo to World War 11.77>23 counting technique. dium patients, marked excesses of chromosome a. Traces of plutonium were de- tected by counting the hands of several subjects known to have hand wounds while working with plutonium in 1944 or 1945. located in one case The site was precisely (subject No. estimated to be 5.3 + 0.4 nCi. 1) and the amount Of interest is the In both Thorotrast and rations were reported. Because of observations of chronic lympho. in dogs exposed to plutonium oxide aerosols, o: might expect to observe chromosome damage in 1: cytes of exposed plutonium workers. This obse: observation that the subject erroneousiy thought tion led Dolphin?“ to investigate the possibil: that the wound was on the other hand. of chromosomal aberrations in lymphocyte cultur At present, the skin overlying the active site appears to be obtained from workers in England known to have grossly normal except for minimal scaling. exposed to plutonium. We plan He compared the findings to make additional measurements on and cbservations 8 plutonium workers who had been exposed to plu of this deposit in the future. nium plus 14 rads of external irradiation over D. year period with workers who had received exter Chromosome Analysis irradiation only and found that the dicentric y During the 1971-1972 visit to the LASL, blood of lymphocytes of the plutonium workers could b. samples were obtained from the UPPU group for chro- accounted for by the extemal radiation dose re- mosome studies using standardized, ceived by the workers. established Dolphin@4 also cites an Aithough no abnormalities were found other case in which a plutonium worker was foun in these subjects, we plan to add newly developed by chest-counting, to have 10 to 20 times the pe chromosome banding techniques to our procedures missible level of plutonium in the lung about techniques. when the group is next studied. During recent years, considerable interest has 3 years after an inhalation accident. Chromosor analysis indicated minimal radiation damage to t been directed at the effects of various stressing lymphocyte series even at a high level of expos. agents on chromosomes of lymphocytes in the per- of the patient. ipheral blood. chromosomes obtained from uranium miners exposec The induction of chromosomal aber- rations in human peripheral leucocytes has been 18 Other investigators are studyir. a variety of stressing agents, including radiati