Cause of Death and Neoplasia in Mice Continuously Exposed to Very Low Dose Rates of Gamma Rays
| Autor: | Satoshi Tanaka, Izumi Tanaka, Kazuaki Ichinohe, H. Otsu, Tsuneya Matsumoto, Fumiaki Sato, Satoru Matsushita, Y. Oghiso |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2007 |
| Předmět: |
Male
Pathology medicine.medical_specialty Neoplasms Radiation-Induced Biophysics Physiology Biology Radiation Dosage Mice Sex Factors medicine Animals Radiology Nuclear Medicine and imaging Survival rate Survival analysis Cause of death Radiation Low dose Body Weight Gamma ray Myeloid leukemia Dose-Response Relationship Radiation medicine.disease Survival Analysis Survival Rate Dose–response relationship Hemangiosarcoma Gamma Rays Female Whole-Body Irradiation |
| Zdroj: | Radiation Research. 167(4):417-437 |
| ISSN: | 0033-7587 |
| Popis: | Four thousand 8-week-old SPF B6C3F1 mice (2000 of each sex) were divided into four groups, one nonirradiated (control) and three irradiated. The irradiated groups were exposed to (137)Cs gamma rays at dose rates of 21, 1.1 and 0.05 mGy day(-1) for approximately 400 days with total doses equivalent to 8000, 400 and 20 mGy, respectively. All mice were kept until natural death, and pathological examination was performed to determine the cause of death. Neoplasms accounted for86.7% of all deaths. Compared to the nonirradiated controls, the frequency of myeloid leukemia in males, soft tissue neoplasms and malignant granulosa cell tumors in females, and hemangiosarcoma in both sexes exposed to 21 mGy day(-1) were significantly increased. The number of multiple primary neoplasms per mouse was significantly increased in mice irradiated at 21 mGy day(-1). Significant increases in body weights were observed from 32 to 60 weeks of age in males and females exposed to 1.1 mGy day(-1) and 21 mGy day(-1), respectively. Our results suggest that life shortening (Tanaka et al., Radiat. Res. 160, 376-379, 2003) in mice continuously exposed to low-dose-rate gamma rays is due to early death from a variety of neoplasms and not from increased incidence of specific neoplasms. |
| Databáze: | OpenAIRE |
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