a PRIVACY ACT MATERIAL REMOVED’ : ® roid then resulted in a substantially larger dose. — The total estimated dose from the various iodine isotopes to the child’s gland was about 1000 rads, — with a range of 700 to 1400. The glands received an additional! 175 rads from external gammaradiation. Details of these calculations have been given by James and Ng andare presented in Appendix 2. Althoughthe skin overlying the thyroid gland was frequently the site of “beta burns” as shownin Figure 20, the deposit of radioactive materials in this area probably did not addsignificantly to the thyroid dose, since most of the beta irradiations were too weak to have penetrated to the depth of ‘the gland. Previous Thyroid Studies Figure 20. ‘Beta burns”of neck (subject No. 39, March 1954). The area over the thyroid was a frequentsite of | burns. care has been taken to ensure that glassware and syringes were not contaminated with iodine. This can be seen bythe fact that thetotal iodineis not markedly greater than the PBI and by the normal x Until 1963 no thyroid abnormality was detected in either the exposed or the comparison population, except for one case of asymptomatic diffuse thyroid enlargementseen in an unexposed woman. It has not been possible to perform basal metabolism rate determinations, but.careful physical examinationof the thyroid and a variety oftests of thyroid function have been performed during the previous surveys. Protein-Bound lodine.** The serum proteinboundiodine has been determined by the methods of Foss et al.?* at Brookhaven National Laboratory, the Boston Medical! Laboratories, and Bio-Science Laboratories, Van Nuys, California. In addition, estimation of the butanol-extractable iodine of oe ee ee serum was doneat Bio-Science Laboratories, and also column chromatographyofthe serum iodine by a modification of the method of Galton and Pitt-Rivers.*° In several instances the capacity of thyroxine-binding alpha globulin (TBG) was measured at NIH by a method described previously.*” Theresults of analyses for iodine in serum are shown in Table 14. (See Appendix 3 for complete protein-bound iodine data.) It is apparent that on several occasions and with several different methods the average serum protein-boundiodinein the inhabitants of both Rongelap and Utirik is higher than normal, and that from 16 to 64% of the natives on Rongelap and 90% on Utirik show values that are above the normal range by American standards. Nosignificant differences in the PBI levels have been noted between the group that had been exposed to radiation and the'unexposed group. Thefirst results showing an elevated PBI were obtained in 1958, and since that time 5008309 * values for PBI obtained in 1964 on membersof the medical team, whose blood was obtained at the same time and under the same conditionsas that of the natives. The elevation in PBI could be due to a general increase in serum PBI in all the Rongelap population,or it could be due to the occurrence of some genetic difference, so that a sub- stantial fraction of the population shows abnor- mally high PBIs and the remainderof the popula-. tion is normal. In thefirst case, a plot of the level of PBI versus frequency of occurrenceat thatlevel would show a normaldistribution, except that the whole curve would be displaced about 2 pg% up- | wards. In the secondcase,the distribution curve would be bimodal, and a family tree would show familial clustering, the precise type depending on the mannerof inheritance. Figure 21, a distribu- tion curve of PBI level versus incidence at that level, shows no evidence for a bimodaldistribution. The low numberof PBI values between 7.75 and 8.0 ug% seemsto be dueto statistical fluctuation because of the small numbers of cases. Fur- ‘thermore, the elevated values (defined as those above 8.0 1g%) did not show a familial pattern of distribution. It appears, therefore, that the eleva- PRIVACY ACT MATERIAL + REMOVED