The present study was carried out to obtain further information on the relation-ship between primary carcinoma of the liver and infection with a liver-fluke, Clonorchis sinensis.
A group of 50 male albino mice were used. Approximately 500 metacercariae were given´ orally to each mouse. Maturity of worms was followed up by fecal examination- Distribution of worms in the hepatobiliary system was also checked by using 5´ egg positive mice at the end of the 1st month of infection. For histopathological examination, 4- 5 mice were sacrificed monthly through the 9th month of infection. The liver tissues including common bile duct and the gall bladder were fixed in 10% formalin, sectioned serially, and stained with hematoxylin and eosin.
The results obtained are summarized as follows;
1. The initial day of egg output was the 28th day in average ranging from 22nd to 33rd day of infection.
2. Recovery rate of worms was revealed: as low as 16.8 ofo, and of which 64.5 % was found in the intrahepatic ducts, 33.2% in `common bile duct and 2.3% in the gall bladder,
3. Parasites were found in the intrahepatic ducts throughout the observation.
4. At the end of the 1st month of infection, epithelial cells of bile ducts showed varying degrees of hyperplasia and desquamation, marked adenomatous tiss-
ue proliferation, enormous acini formation with remarkable mucinous cell metapla sia and definite atypia. Stratification was scanty. Periductal and portal spaces demonstrated the extensive chronic mononuclear leucocytes and the.moderate fibrosis. Similar pictures persisted up to the 4th month of infection.
5. After the 5th month, all of the outstanding features of epithelial cells show-e4 gradual regression. On the other hand, the most striking picture in this period was the great increase of collagen fibers in periductal and portal spaces.
Although tumors were not found in the present study, overall results obtained were strongly suggestive to make an inference that clonorchiasis is responsible for the neoplastic transformation of epithelial cells of intrahepatic bile ducts in experimentally infected albino mice.
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