OFFICIAL USE ONL _ by DBM to study the long term toxic effects of plutonium relative to radium utilizing beagle dogs as the experimental animal. In their original experimental design, they injected six groups of dogs with plutonium at doses ranging from .016 to 2.88 microcuries/kg body weight. An additional control group was included. At present all but one of the dogs is dead. Osteosarcomas were found in all the treated groups and no osteosarcomas were found in controls. They later set up a second phase of the study in which the radiation doses went down from .015 to .00064 microcuries/kg. None of these animals has yet died and none has yet shown an osteogenic sarcoma but the experiment has gone less than ten years. It might be noted that in the first phase of the study the lowest treatment group represented an endosteal radiation dose of approximately 1600 rads of alpha particles. It is perhaps not surprising, then, that these animals developed their sarcomas. Dr. Jee felt that small doses of radionuclides permitted bone remodeling so that retention of the radionuclides was not as high as it was at the higher doses. At high doses remodeling is inhibited and thus the removal of the nuclide is impeded. In the case of the liver, the effect works in the opposite direction. High doses kill the cells and thereby permit removal. Dr. Jee also outlined a number of proposed studies. Dr. Newton, from Battelle Northwest, reported on the status of the transuranium registry. The purpose of this registry is to keep track of personnel exposed to transuranic elements with the ultimate hope of correlating exposure information with morbidity, mortality, type of disease, and assays of the radionuclide content of tissues at death. A large number of contractors and licensees are included in these studies. They are presently following 100 men with significant levels of plutonium. Assays are made every two years of the amounts excreted and medical examinations are provided every five years. The biological specimens are processed for radionuclide content at Los Alamos, Rocky Flats and Hanford. Cross checks of the methods and results are conducted. At the Hanford works there are 2000 identified workers who have had potential exposure to transuranic elements. Two hundred and seventy-four of these are known to have some deposition in the body. An attempt is being made to obtain permission for autopsies at the time of death of these workers under the act permitting the donation of bodies. Four hundred of the 2000 workers at Hanford have signed autopsy permits. Protocols for conducting autopsies are being standardized. In addition to the workers at Hanford, there are presently 2500 workers at Rocky Flats with potential exposure and another 2500 that have been terminated from their jobs for one reason or another. One hundred of these workers are known to have significant deposition of transuranic elements. There are a number of additional workers with lower body burdens, A11 told, there are about 10,000 potential exposure cases at the present time in the United States. There have been 14 autopsies in the sample being followed by the piutonium registry in the past year. They are making assays from various portions of the body to examine the magnitude of the inhomogeneities in deposition of the radionuclides. Presently, England,Russia, and Japan all plan to establish transuranium registries and will exchange data with the U. S. Registry. OFFICIAL USE ONLY