| Budget Amount *help |
¥2,100,000 (Direct Cost: ¥2,100,000)
Fiscal Year 1993: ¥1,000,000 (Direct Cost: ¥1,000,000)
Fiscal Year 1992: ¥1,100,000 (Direct Cost: ¥1,100,000)
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| Research Abstract |
Epidemiological studies of biliary tract cancer(BTC) have been conducted over the last decade, the rationale being that the deaths rates in Niigata Prefecture where we live were found to be the highest in Japan. The present study was conducted as a part of the epidemiological studies on BTC.The aim of the present study is to test a multifactorial causation hypothesis by making use of an animal model. In details, we designed a protocol on the basis of multifactorial causation hypothesis where a suspected chemical, chlornitrfen(CNP) is given to golden hamsters whose gallbladders are surgically operated to have "experimental gallstone".
Five experimental groups were established as follows ; Group 1 : gallstone + normal diet, Group 2 : gallstone + CNP(5000ppm), Group 3 : positive carcinogen, 3-methylcholanthrene (3-MC) + nomal diet, Group 4 : 3-MC + CNP(5000ppm), Group 5(Control Group) : sham-oparation + nomal diet. Twenty female golden hamsters (9-10 weeks age at the time of initiation were used in each group. The periods of experiments were 72 weeks in the groups of 1,2 and 5, and 17 weeks in the groups of 3 and 4. CNP treatment in the group 2 was stopped at the 17th weeks and normal diet was introduced in the rest of the experimental period, since the body weight increase was affected as compared with the control group.
During the course of experiment for 72 weeks in the groups of 1,2 and 5, three animals each were dead. In the groups of 3 and 4, none of them died for 17 weeks. At the time of sacrifice(72 weeks in groups of 1,2 and 5, and 17 weeks in the groups of 3 and 4), 1 and 2 cases of hyperplastic nodules in the liver were found in the groups of 1 and 2, respectively. In regards to the occurence of gallbladder cancer, the histopathological examination was being conducted and the details of the findings will be appeared elsewhere.
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