Intracellular lumina and bile canaliculi in rat hepatocytes in vitro--a cytochemical study.

Within a few hours after being placed in culture, isolated rat hepatocytes reassociate into clusters and differentiate intercellular cavities bordered by junctional complexes. These structures bear a strong resemblance to the bile canaliculi found in the liver. If the plating is impaired by permanent agitation, intracellular lumina surrounded by microvilli appear in the cytoplasm of some isolated hepatocytes.

Spontaneous and induced dome formation by two clonal cell populations derived from a human adenocarcinoma cell line, HT29.

The replacement of glucose by galactose in the culture medium resulted in partial structural and functional enterocytic differentiation of HT29 cells. In order to characterize populations of homogeneously differentiated HT29 cells we have selected two clonal cell lines HT29-D4 and HT29-D9 with the following functional and structural characteristics when grown in a galactose-containing medium: the two clonal cell populations were permanently morphologically differentiated as shown by the presence of mature junctional complexes and a well-organized brush border (especially for HT29-D4 cells); HT29-D4 and HT29-D9 cells were able to form domes early in confluency, which indicated a functional state of differentiation; the process of differentiation was fully reversible when glucose was added to the culture medium. The induction of domes was investigated in these two cell populations and we demonstrated for the first time that proteolytic enzymes are potent inducers of dome formation.

Ultrastructural observations of the abducens nucleus of the cat after injection of horseradish peroxydase into the lateral rectus muscle.

The ultrastructure of cat abducens motoneurones is described, after labelling by retrograde axonal transport of horseradish peroxydase. The motoneurones were densely covered with synaptic boutons of both the "terminal" and "en passant" types and axo-axonal synapses were observed on the initial segment of motoneurone axons. Within the population of axons forming the VIth nerve, multiple branching was encountered and axons closely apposed at the nodes of Ranvier were seen.