Lung carcinogenesis in rats after inhalation exposure to (237)NpO2.

The results of several studies of experimental carcinogenesis suggest that, after inhalation of alpha-particle emitters, lung tumor incidence varies depending on the exposure rate and dose distribution in the tissue. In the case of transuranics, the main influencing factor would be the specific alpha-particle activity of the inhaled actinide. To confirm these results, long-term studies were performed using male Sprague-Dawley rats exposed to (237)NpO(2) by inhalation.

Localization of plutonium retention in the small intestine of the neonatal rat, guinea pig, baboon and macaca after Pu-citrate ingestion.

The retention of Pu-citrate in the gastrointestinal wall was compared at similar post ingestion times after ingestion at 2 days of age by rats and guinea pigs and at 1 to 34 days by neonatal primates. The small intestine was the main site of the Pu retention in all species. In rats and primates, most of the Pu was retained in the distal ileum, whereas in guinea pigs it was more homogeneously distributed.

[Consequences of pulpectomy followed by canal obturation on the renewal of periodontal ligament in the baboon (Papio papio)].

Endodontic root filling following pulpectomy in Baboons was shown to induce diphasic consequences at the level of the periodontal ligament according to the time of the observation. Initially the specific activity of previously incorporated 3H Glycine decreased and the weight of extractible ligament increased at the same time. Later on, the turnover slowed down and, unexpectedly, the weight of the extractible ligament decreased.