Hemoblastoses in mice contaminated with low activities of 239Pu.

Female ICR mice were injected intravenously with low activities of 239Pu (3.0 kBq, 6.0 kBq, 12.3 kBq/kg). In these mice with high spontaneous incidence of hemoblastoses the occurrence of myeloid leukemia, lymphocytic leukemia, lymphosarcoma, reticulum-cell sarcomas and osteosarcoma was studied. Hemoblastoses, on the whole, remained in their numbers radiation-independent, nevertheless, the distribution into specific types changed, with moderate prevalence of myeloid and lymphocytic leukemia and lymphosarcoma. After plutonium injection the mean survival time of mice bearing myeloid and lymphocytic neoplasias was significantly shorter than the survival of mice that died of retothelosarcoma and from other causes. These contamination-dependent differences could not be observed in matched controls. As expected, 239Pu activities used in this experiment induced osteosarcomas. Whereas in leukemogenesis alpha-radiation appeared as a factor promoting and modifying the leukemogenic process, in osteosarcoma the alpha-particles acted rather as an initiator, the effect of which was dependent on the dose to the endosteal progenitor cells.