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nase and ornithine transcarbamylase, showed no correlation with the growth rate or histological type. From a survey of isozyme patterns of several enzymes he tried to quantitate malignancy of these experimental hepatomas; he studied several isozymes including lactate dehydrogenase, glucose-6-phosphate dehydrogenase, glutamic-oxalacetic transaminase, glutamic-pyruvic transaminase, malate dehydrogenase, and a-glyceroaldehyde dehydrogenase. Ono showed that the isozyme pattern of the LDH (lactic dehydrogenase) of all ascites hepatomas tested retained essentially the normal pattern of rat liver, and that the variation among the 53 Yoshida strains was caused in part to a gradation of differentiation.The "minimal-deviation" type hepatomas exhibited the well differentiated pattern similar to that of normal adult liver. Although one minor peak of the glucose-6-phosphate dehydrogenase isozyme was deleted in a few cases no abnormal isozyme pattern was observed. Ono proposed three biochemical parameters which could possibly be used to quantitate malignancy of experimental hepatomas: (i) enzyme activities which correlated either positively or negatively to the growth rate (glucose-6-phosphatase, and glutamate dehydrogenase), (ii) independence of inducible or suppressible enzymes from host control (tryptophan pyrrolase and glucose-6-phosphate dehydrogenase), and (iii) systemic effect of hepatomas on the host liver enzymes, such as catalase activity.In his closing remarks W. Nakahara (National Cancer Center Research Institute, Tokyo) referred to the historical background of his early studies on the catalase activity in tumor-bearing animals. He emphasized that extensive studies on the cell membrane might be desirable for better understanding of malignancy, because less adhesiveness and invasiveness were common during the oncogenic processes.The symposium clearly established that a continuous spectrum of hepatomas revealing different growth rates represented many degrees of progression of cancer cells and that more studies were vital. The clinical symptoms or signs, growth rate, transplantability, and others, used in the past must now include both the biochemical and biological approaches. These newer ap-nase and ornithine transcarbamylase, showed no correlation with the growth rate or histological type. From a survey of isozyme patterns of several enzymes he tried to quantitate malignancy of these experimental hepatomas; he studied several isozymes including lactate dehydrogenase, glucose-6-phosphate dehydrogenase, glutamic-oxalacetic transaminase, glutamic-pyruvic transaminase, malate dehydrogenase, and a-glyceroaldehyde dehydrogenase. Ono showed that the isozyme pattern of the LDH (lactic dehydrogenase) of all ascites hepatomas tested retained essentially the normal pattern of rat liver, and that the variation among the 53 Yoshida strains was caused in part to a gradation of differentiation.The "minimal-deviation" type hepatomas exhibited the well differentiated pattern similar to that of normal adult liver. Although one mino...

An extensive review of animal and human metabolism data for selected radionuclides is presented in an attempt to assess the value of animal research and subsequent extrapolation of the results to man. Since isotopes of related elements generally follow similar metabolic pathways, radionuclides of biological importance were selected and grouped by their respective chemical families. Criteria for selection included world-wide atmospheric contamination, general use in medicine and industry, contribution to the natural radiation environment and their radiotoxicity. In this review, reported results, supplemented by original work, were compiled for the following radionuclides: 13'Cs for the alkali metals; 9OSr and zzaRa for the alkaline earths;z3ePu for the lanthanides and actinides; lS1I for the halides; 210Po and aloPb for the transitional elements; and lo6Ru for the transition metals. An appraisal of biological effects and of therapeutic or preventive methods for each radionuclide is also given.Comparative studies of hazardous radionuclides in animals are necessary since they provide basic data useful for assessment of their metabolic pathways and response in man. Animal data are especially valid when values are obtained for several species from different mammalian sub-families with life spans ofdifferent duration. In certain cases, however, the data suggest species specific metabolic pathways for individual isotopes. The authors conclude that extrapolation to man from animal data is admittedly difficult and sometimes inaccurate; however, the risks in not extrapolating are unquestionably greater.

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