| Popis: |
The malignancy of pulmonary lesions induced by inhaled 239PuO2 in the Syrian hamster was tested by transplantation in the hamster cheek pouch. Serving as negative and positive controls, 42 female hamsters were given either 0.9% sodium chloride (NaCl), ferric oxide suspended in NaCl (Fe2O3), or benzo(a)pyrene + Fe2O3 suspended in NaCl (BP), by intratracheal instillation. One hundred female hamsters were given a single, nose-only inhalation exposure to high-fired 239PuO2 (initial lung burden, 2.4 kBq). At intervals from 160 to 425 days after Pu inhalation or instillation, ten 1-mm3 tissue cubes were removed from the lung of each hamster and transplanted into the cheek pouch of male hamsters, for a total of 1320 transplantations. None of the lung transplants from hamsters receiving 239PuO2, NaCl, or Fe2O3 grew in recipient cheek pouches, but 14% of transplants from BP hamsters grew rapidly in the cheek pouch. Lung carcinomas were histologically identified only in BP hamsters and BP transplants. It was concluded that proliferative pulmonary lesions induced by a-irradiation of the lung of hamsters were not malignant, and that the malignancy of lung lesions in the hamster induced by ionizing radiation should be evaluated by transplantation. |
