Interphasic nucleolar organizer regions expression and cell kinetics evaluation during gastric carcinogenesis induced by nitrosoguanidine in the rat

Isolation, culture and characterization of biliary epithelial cells from different anatomical levels of the intrahepatic and extrahepatic biliary tree from a mouse

We developed methods to isolate biliary epithelial cells (BECs) from the gallbladder (GB), common bile duct (CBD), intrahepatic large bile duct (ILBD) and small bile duct (ISBD) of a mouse, simultaneously. ILBD and ISBD were cut from the biliary tree after collagenase perfusion of the liver. BECs from all of these biliary segments were cultured as explants on collagen gel. BECs spread from the explants and formed cellular sheets. Areas of these sheets composed entirely of BECs were cut and placed on other gels as subculture, and this continued for 10 passages. Primary and passage cultured BECs on gel were composed of a monolayer of epithelial cells. Passaged cultured BECs in gel formed a spherical cyst lined by a single epithelial layer. Ultrastructurally, microvilli were dense on the luminal surface, and junctional complex and interdigitation was identifiable on the lateral surfaces. These features were similar in both primary and passaged cultured BECs, irrespective of their anatomical origin. Major histocompatibility complex antigens and intercellular adhesion molecule-1 were induced on the basolateral cell membranes of primary and passaged cultured BECs, by interferon-gamma. Although several phenotypic, structural and probable biological features of BECs inherent to each anatomical level may be lost after culture on gel, a combination of this method, several immunological modifications in experimental animals, and addition of immunologically active substances to the culture medium will make the immunopathologic analysis of biliary diseases possible.

The proliferative activity in oral epithelial dysplasia analyzed by proliferating cell nuclear antigen immunostaining and argyrophilic nucleolar organizer region staining

The proliferative activity of leukoplakia without dysplastic change (LP), epithelial dysplasia (ED), and squamous cell carcinoma (SCC) in the oral mucosa was examined by means of proliferating cell nuclear antigen (PCNA) immunostaining, silver-binding argyrophilic nucleolar organizer region (AgNOR) staining, and the frequency of mitotic figures. Significant differences in the labeling index of PCNA immunostaining (PI) and mitotic index (MI) were noted between LP and ED and between ED and SCC. The mean numbers of AgNORs (AI) significantly differed between ED and SCC. There was a significant positive correlation between PI and MI in samples of ED. However, there was no significant correlation between AI and other indexes. The number and the distribution of PCNA-positive cells in ED varied among samples. Five samples with higher PI and MI indexes than the mean values were selected from those of dysplasia based on the correlation between PI and MI. Their histological features symptomatic of oral ED as defined by the World Health Organization (WHO) Collaborating Centre in 1978, were investigated and compared with 10 samples with lower indexes. Histological findings, such as "loss of polarity of the basal cells," "an increased nuclear-cytoplasmic ratio," "cellular pleomorphism," and "enlarged nucleoli," were significant histological features of these five samples. This study showed that the four histological components described previously and the increased number of mitotic figures used as the index of proliferating activity were the main histological components related to severe ED of oral mucosa. They will provide a useful means of deciding the histopathological grade of oral ED.