bromochloroacetic-acid and Liver-Diseases--Parasitic

Oval cells which appear in the liver after hepatic injuries are suspected to be progenitor cells for both hepatocytes and bile duct cells. Oval cell isolated from the livers of the hamsters treated with diethylnitrosamine and 2-acetylaminofluorene and infected with Clonorchis sinensis (CS). cultured for 2 weeks and evaluated for differentiation and plasticity by electron microscopy and immunohistochemistry. In the CS-uninfected group, glycogen granules and peroxisomes were noted in the cells that were cultured for 2 weeks. Starting at 1 week postculture, immunoreactivity of the cells to cytokeratin 19 markedly decreased but that to albumin and alpha-fetoprotein gradually increased. This means that oval cells isolated from hamsters that were not infected with CS differentiated toward hepatocyte lineage. However, in the CS-infected group, cultured cells contained numerous rough endoplasmic reticulum and showed immunoreactivity that was generally in reverse to that of CS-uninfected group, meaning that cells isolated following CS infection were primed by CS and differentiated toward bile duct cell lineage. The results of this study suggested that oval cells are indeed bipolar progenitor cells for hepatocytes and bile duct cells and can differentiate toward either lineage depending upon the priming factor.

Topics: 2-Acetylaminofluorene; Albumins; Alkylating Agents; alpha-Fetoproteins; Animals; Carcinogens; Clonorchiasis; Clonorchis sinensis; Cricetinae; Diethylnitrosamine; Immunohistochemistry; Keratins; Liver; Liver Diseases, Parasitic; Male; Mesocricetus; Microscopy, Electron; Rodent Diseases

Two of five male Sprague-Dawley rats with hepatic tapeworm cysts developed large multinodular fibrosarcomas. Fibrosarcomas envelope tapeworm cysts, invaded the serosa of multiple organs, and extended through the diaphragm into the pleural cavity. Light microscopy, immunohistochemistry, and electron microscopy supported the diagnosis of fibrosarcoma. The parasites were identified as Cysticercus fasciolaris, the larval stage of Taenia taeniaeformis. The development of sarcomas in rats induced by Taenia sp. is thought to be attributable to the chronic inflammatory reaction of the capsule. There are parallels between these and other tumors occurring in mice and cats with suggested chronic inflammatory etiologies.

Topics: Animals; Cysticercosis; Cysticercus; Desmin; Fibrosarcoma; Immunohistochemistry; Keratins; Liver; Liver Diseases, Parasitic; Liver Neoplasms; Male; Microscopy, Electron; Rats; Rats, Sprague-Dawley; Rodent Diseases; Vimentin