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LIGHT MICROSCOPICAL AND ELECTRON MICROSCOPICAL COMPARISONS OF NORMAL HEPATOCYTES OF WELL-DIFFERENTIATED HEPATOCELLULAR CARCINOMAS IN A TELEOST FISH
Citation:
Couch, J. LIGHT MICROSCOPICAL AND ELECTRON MICROSCOPICAL COMPARISONS OF NORMAL HEPATOCYTES OF WELL-DIFFERENTIATED HEPATOCELLULAR CARCINOMAS IN A TELEOST FISH. U.S. Environmental Protection Agency, Washington, D.C., EPA/600/J-94/011 (NTIS PB94140696).
Description:
Well-differentiated hepatocellular carcinomas (HCC's) induced in the sheepshead minnow (Cyprinodon variagatus) with N-nitrosodiethylamine, permitted light microscopical and ultrastructural comparisons of normal hepatocytes and adjacent HCC cells. ormal hepatocytes contained typical organelles with their intracellular distribution similar to that described for other teleosts. hese cells revealed a strong compartmentalization of organelles consisting of restricted perinuclear cytoplasm containing rough endoplasmic reticulum (RER) and mitochondria; most of the rest of the volume of the cytoplasm of the cell was filled with glycogen particles. djacent HCC cells at the border of the neoplasm interdigitated (invaded) between normal hepatocytes and replaced normal hepatocytes close to the HCC edge and adjacent to the bile canaliculi. ithin the HCC, cons had little intercellular space between them and atypical bile canaliculi were found occasionally between adjacent hepatocytes. he HCC cells appeared to differ mainly in a quantitative, rather than in a quantitative fashion, and in the distribution of organelles from normal hepatocytes. CC cells were not compartmentalized, their organelles (RER and mitochondria) were distributed throughout the cytoplasm, and only small amounts of glycogen remained diffusely distributed or in small masses or foci. itochondrial intermembrane myelin bodies (MMB's) were found frequently in the HCC cells but less frequently in the normal hepatocytes. ome cells at the edge of the HCCs appeared to be intermediate in terms of abundance and distribution of organelles and glycogen, between inner HCC cells and normal hepatocytes. he possible significance of the MMB's and intermediate, edge cells is discussed, as well as the need to better characterize features of well-differentiated hepatic neoplasms in order to assure their proper inclusion in neoplasm incidence/prevalence data in fish carcinogenesis assays and field studies.