4 0 0 0 IR 社会的笑いに関する心理学研究の動向
- 著者
- Yun-Shan Li Ming-Fen Song Hiroshi Kasai Kazuaki Kawai
- 出版者
- 日本環境変異原学会
- 雑誌
- Genes and Environment (ISSN:18807046)
- 巻号頁・発行日
- vol.35, no.3, pp.88-92, 2013 (Released:2013-09-03)
- 参考文献数
- 16
- 被引用文献数
- 1 10
Human epidemiological studies have revealed significant increases in the cancer incidence rates by exposure to 100 mSv or higher doses of ionizing radiation. However, the relationship between lower doses of ionizing radiation and cancer incidence is still unclear. In general, oxidative DNA damage is closely related to cancer generation. We studied the oxidative DNA damage elicited by low dose ionizing irradiation. The γ-ray irradiation of a deoxyguanosine solution caused a linear increase in the 8-hydroxydeoxyguanosine (8-OHdG) levels, in the range of 20-300 mGy. Thus, 8-OHdG seems to be a good marker of the oxidative DNA damage caused by ionizing radiation. In contrast, in the case of the whole body X-ray irradiation of mice, the 8-OHdG levels in liver DNA and urine increased from about 500 and 200 mGy, respectively. These results indicate that living organisms have a defense mechanism against the oxidative damage caused by ionizing radiation. Considering the 8-OHdG levels as an ionizing radiation effect marker for living organisms, a threshold level of irradiation seems to exist for oxidative damage and tumorigenesis. Furthermore, diet imbalances increased radiation damage. Lifestyle may affect the radiation hazard.
- 著者
- Yun-Shan Li Kazuaki Kawai Hiroshi Kasai
- 出版者
- The Japanese Environmental Mutagen and Genome Society
- 雑誌
- Genes and Environment (ISSN:18807046)
- 巻号頁・発行日
- vol.29, no.3, pp.128-132, 2007 (Released:2007-09-12)
- 参考文献数
- 24
- 被引用文献数
- 7 6
To clarify the in vivo genotoxic potential of dietary style, the amounts of 8-hydroxydeoxyguanosine (8-OH-dG), a marker of oxidative DNA damage, were determined by a high-performance liquid chromatography system coupled to an electrochemical detector (HPLC-ECD) in the urine of female mice to which a vitamin-deficient diet (for two months) and a sweet beverage (for two weeks) were administered. The urinary 8-OH-dG levels were clearly increased in these studies. In the vitamin-deficient diet experiment, the urinary 8-OH-dG levels were increased to 1.2-fold and 1.4-fold after one month and two months, respectively. When mice were given a commercially available sweet beverage instead of water for two weeks, the urinary 8-OH-dG was increased to 1.4-fold. In the sweet beverage experiment, significant increases of the volume consumed per day were observed, as compared to the control group (water). Although the total caloric intake per day was not remarkably different between the sweet beverage- and control-group, the mice in the sweet beverage group obtained a higher ratio of calories from sugar components. These results indicated that the elevation of oxidative stress could be caused by the prolonged intake of an unbalanced diet, such as a vitamin-deficient diet or one including sweet beverages.