著者
Takashi Kitabatake Shinji Takahashi
出版者
Tohoku University Medical Press
雑誌
The Tohoku Journal of Experimental Medicine (ISSN:00408727)
巻号頁・発行日
vol.94, no.1, pp.37-43, 1968 (Released:2008-11-28)
参考文献数
14
被引用文献数
1 1

A linear accelerator applied to conformation radiotherapy was described. The mechanism and dose distribution in the linear accelerator conformation radiotherapy were discussed, together with a comparison with those in telecobalt therapy. In this machine a collimator was divided into six leaves, which were driven independently by a servo system following signals given by the signal generator. The mechanical error in this system was within a range of +1.47 to-1.80%. The size and shape of radiation-dense area, ‘beam focus’, made by this unit sufficiently coincided geometrically with the region of planned treat-ments. The homogeneity of dose distribution was better than that by telecobalt gamma-rays.
著者
Ryo Kamata Fujio Shiraishi Shinji Takahashi Akira Shimizu Daisuke Nakajima Shiho Kageyama Takushi Sasaki Kyosuke Temma
出版者
日本毒性学会
雑誌
The Journal of Toxicological Sciences (ISSN:03881350)
巻号頁・発行日
vol.38, no.6, pp.903-912, 2013-12-01 (Released:2013-11-09)
参考文献数
27
被引用文献数
2

In the 1950s to 1970s developed countries reported declines in populations of raptorial and fish-eating birds and dichlorodiphenyltrichloroethane (DDT) and its metabolites were considered causative substances because they accumulated significantly in the tissues of wild birds and animals. However, except for the estrogenic effects of o,p’-DDT, a minor component of commercial DDT, there has been no compelling evidence that DDT directly affects avian reproductive systems. To assess the possible impact of DDT on development and reproduction of birds, exposure experiments to the major component of commercial DDT, p,p’-DDT, and its persistent metabolite, p,p’-dichlorodiphenyldichloroethylene (DDE), were performed using Japanese quail (Coturnix japonica) eggs; the test substances (3 to 100 μg/g) were injected into the yolk prior to incubation, and hatched chicks were raised to adulthood. p,p’-DDT had no significant effects on the morphology and function of the reproductive systems, although the hatchability of treated eggs was reduced at the highest dose (100 μg/g). High doses of p,p’-DDE slightly enhanced the eggshell forming ability of female quails; eggshell mass and thickness were increased at 30 μg/g or more although no morphological changes were observed in the oviduct. Transcriptions of the CYP11A1 gene in the ovaries, and of AHR and ARNT in the livers, of adult females were significantly increased at 3 μg/g or more of p,p’-DDT. Except for low hatchability, transovarian exposure to p,p’-DDT or p,p’-DDE did not markedly impair the avian reproductive systems, but the hormonal actions of these compounds are likely to change reproductive and hepatic functions even after maturation.