12 " scores into 5-year age groups was done to reduce possible errors due to the uncertainty of the exact age of someindividuals. DENTAL SURVEY Dental examinations were carried out on most of the people on the island, particularly those requiring dental attention. LABORATORY PROCEDURES Hematological Examinations Complete routine blood counts were carried out with repeat counts on any persons showing abnor- malities. White blood counts and red blood counts were obtained with the electronic Coulter, which again proved to be a very sdtisfactory instrument for examinationsof this type in the field. Differential counts were performed in the usual manner after staining with Wright’s fluid. Platelet counts were done by phase microscopy. Hemoglobin was determined bythe cyan-hemoglobin technique with the Lumitron colorimeter, but only 49 deter- minations were possible because of breakdown of the Lumitron. Hematocrits were obtained bythe . microhematocrit method. Reticulocyte counts were carried out in 16 people who had low hemoglobin values. Serum proteins were determined with the Hitachi refractometer. Blood and serum samples for certain studies to be described below were collected and kept underrefrigeration and finally shipped back for study. Urine Analysis Routine urine analyses were done on almostall people receivingphysical examinations. These included determinations of protein and hyperglucosuria by reagent paperstrips. * _ Serum Examinations for Calcium, Phosphorus, and Protein Bound lodine These studies were carried out in six of the chil- dren in the exposed group of the growth and developmentstudy. ** *Combistix, Ames Company, Inc., Elkhart, Indiana. **We are grateful to Drs. D.D. Van Slyke and L.V. Hankes of this Laboratory for carrying out these determinations. Serum lron Serum iron determinations were performed in the 16 people who were found to have an anemic tendency to see whetherdeficiency ofthis element might be responsible. * Serum Gamma Globulin Studies In previous surveys extensive studies have been made oncertain genetically inherited characteristics such as blood groupings, haptoglobin and transferrin, hemoglobin types, glucose-6-phosphate dehydrogenaseactivity of red cells, B-amino-isobutyric acid excretion, etc. One type of gamma globulin had not been previously studied in the Rongelap people, and 149 sera were collected during this survey for determination of the Gm type of gammaglobulin. The determinations werecarried out by Dr. A.G. Steinberg of Western Reserve University and his collaborators and reported along with the same observations on other populations;* the methods used werealso reported. Radionuclide Body Burden Evaluation The methods used in the radionuclide bod: burden evaluation are described later in a separat section. Results and Discussion The census of Rongelap people in March 196 was 334, of which 81 were in the exposed gro: (including 4 children exposed im utero at the time the accident); 33 were children of exposed paren and 220 were unexposed people; Table 1 sho their location. In Table 2 the population is brok downaccording to percent distribution in varic age groups and compared with that of the Mz shall Islands as a whole for 1948-1950 and oftl United States for 1960. The table also showstl median age. The lower median age of the Ma shallese would tend to support the impression th their life span is shorter than that of peoplein tl continental United States, but there has been “population explosion” in those islands whi might accountfor this discrepancy. “Weare grateful to Mrs. Ruth Saart of South Nassau Cc munities Hospital, Rockville Centre, L.1., N.Y., for carrying the serum iron determinations.

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