@misc{oai:repo.qst.go.jp:00070188,
 author = {Yamada, Yutaka and Nakata, Akifumi and Inoue, Miyuki and Seo, Hitomi and Nishimura, Mayumi and Kakinuma, Shizuko and Oghiso, Yoichi and Shimada, Yoshiya and 山田 裕 and 中田 章史 and 井上 美幸 and 瀬尾 ひとみ and 西村 まゆみ and 柿沼 志津子 and 小木曽 洋一 and 島田 義也},
 month = {Jun},
 note = {Background: The possibility that combined exposures to environmental pollutants and ionizing radiation could increase the risk of lung cancer of the general public is a matter of great concern.  We investigated the combined effects of radiation and a chemical carcinogen on pulmonary tumorigenesis in rats exposed at different age in well-defined exposure conditions.
Material and methods: Female 1-, 5- and 22-week-old Wistar rats were irradiated locally on the thorax with X-rays (3.18 Gy), and/or were given N-nitrosobis (2-hydroxypropyl) amine (BHP; 1 g/kg body weight) intraperitoneally 1 week after thoracic irradiation.
Results: Non-irradiated and non-BHP-injected control rats survived to 90 weeks of age when all rats were sacrificed, but administration of BHP with or without irradiation resulted in survival reduction due to kidney, brain, liver and ovarian tumors.  The incidences of lung tumors including adenomas and adenocarcinomas in rats irradiated alone at 1, 5 and 22 weeks were 8.7, 15.0 and 20.0%, respectively.  On the other hand, the incidences in the rats administered with BHP alone at 2, 6 and 23 weeks were 60.9, 25.0 and 30.0%, respectively.  When a combination of irradiation and BHP was used, the incidences in the rats treated at 1-2, 5-6 and 22-23 weeks were 61.9, 65.0 and 55.0%, respectively. The incidence of adenocarcinomas in the rats treated at 5-6 weeks was significantly increased compared to rats exposed to either X-rays or BHP alone.
Conclusion: The combined effects are age-dependent and administration of BHP after X-ray irradiation synergistically enhances induction of lung adenocarcinomas in juvenile rats.  These results indicate that Wistar rats exposed to X-rays and BHP are a suitable animal model to study the risk and the mechanisms of the combined effects of radiation and chemicals on pulmonary tumorigenesis., 21st Meeting of the European Association for Cancer Research},
 title = {Enhanced pulmonary tumorigenesis by N-nitrosobis (2-hydroxypropyl) amine after thoracic irradiation with X-rays in new born, juvenile and adult Wistar rats},
 year = {2010}
}