Abstract
Summary
Colloidal chromium phosphate suspensions containing graded amounts of P32 were injected intravenously into rats, thus exposing the reticulo-endothelial cells which phagocytized the radioactive colloidal matter to intensive beta radiation. 1. The radioactivity contents of livers were determined in rats sacrificed at different intervals from 1 hour to 10 days after chromium phosphate injection. The amount of radioactivity in the liver remained unchanged during observation period when chromium phosphate injection contained only 0.05 μc of P32. Considerable increase in radioactivity of the liver due to redistribution within the body was observed following the 0.29 μc dose, and still greater accumulation of radioactivity obtained following 0.39 μc. When, however, 17.91 μc were injected, the liver ceased to accumulate radioactive particles. 2. Rats were injected with radioactive chromium phosphate a day before parabiotic pairing with untreated rats; 4 days later radioactivity was found in the livers of the uninjected partners. The portion of the injected amount which was transferred increased with greater P32 content of the chromium phosphate. 3. Radioautographic studies of liver showed changes similar to those following whole body X-irradiation, i.e., distortion of the peripheral lobular pattern and large “sunbursts.” The observed changes are interpreted as indicating great radiosensitivity of the RE system. It is suggested that destruction of this system by injection of isotopes with a shorter range of radiation than P32 could be achieved.
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