Adult rat hepatocytes in primary monolayer culture. Ultrastructural characteristics of intercellular contacts and cell membrane differentiations.

Primary monolayer cultures were obtained in 60 mm petri dishes by incubating 3 x 106 isolated hepatocytes at 37°C in Dulbecco's medium supplemented with 17% fetal calf serum. The ultrastructure of monolayer cells was examined after various incubation periods. Within 4 h of plating, the isolated spherical cells adhere to the plastic surface, establish their first contacts by numerous intertwined microvilli, and form a new hemidesmosomes. After 12 h of culture, wide branched trabeculae of flattened polyhedral cells extend in all directions. Finally, after 24 h of culture, bile canaliculi are reconstituted, and a biliary polarity is recovered: the Golgi elements, which are scattered throughout the cytoplasm in the isolated cells, are reassembled in front of the newly formed bile canaliculi, symmetrically in the adjacent cells; lysosomes are concentrated in that region, and microtubules reappear. Concomitantly, plasma membrane differentiations, namely desmosomes and tight junctions, develop. Tight junctions sealing the bile ducts constitute a barrier to the passage of ruthenium red and horseradish peroxidase. De novo formation of these junctions was studied by the freeze etching technique: 10 nm particles compose a network of anastomosed linear arrays in the vicinity of the bile canalculi; in the next step of differentiation, the particles fuse, form short ridge segments and finally continuous branched smooth strands, characteristic of the mature tight junction.SCOPUS: ar.jinfo:eu-repo/semantics/publishe

Contribution à l'étude de l'onchocercose africaine humaine: Problèmes de prophylaxie à Léopoldville

Doctorat en sciences médicalesinfo:eu-repo/semantics/nonPublishe

Invasiveness of hyperplastic nodule cells from diethylnitrosamine-treated rat liver

Administration of diethylnitrosamine p.o. to female Sprague-Dawley rats induces hepatocellular lesions antecedent to hepatocarcinoma (altered foci and hyperplastic nodules). We have tested hepatocytes from hyperplastic nodules for their invasiveness in vitro, which is a marker for malignancy. The hyperplastic nodule cells are compared with control liver cells and hepatocarcinoma cells. Control liver tissue and the hepatocarcinoma are collected as fragments taken directly from the rat liver. Nodules, on the other hand, isolated by collagenase perfusion of the liver, are collected on a filter. The fragments of normal liver, the nodules, and the hepatocarcinomas were brought in contact with precultured 9-day-old embryonic chick heart fragments for attachment to each other to form confronting cultures. After attachment, the confronting cultures are incubated at 37° on a gyratory shaker for 24 hr to 14 days. Hepatocytes from the nodules show progressive invasion into the precultured heart fragments in the same way as the hepatocarcinoma cells after 3 to 14 days in vitro. The control hepatocytes from the liver fragments showed no invasion. We conclude from these observations that the cells of the nodules must be considered as malignant altered hepatocytes, for they show progressive invasiveness in vitro.SCOPUS: ar.jinfo:eu-repo/semantics/publishe

Démonstration en ME du pouvoir invasif des nodules hyperplasiques et des hépatocarcinomes induits par la diéthylnitrosamine

SCOPUS: NotDefined.jFLWNOinfo:eu-repo/semantics/publishe