In situ detection and distribution of stanniocalcin mRNA in the corpuscles of Stannius of sockeye salmon, Oncorhynchus nerka.

Stanniocalcin (STC) gene expression was examined in the corpuscles of Stannius of sockeye salmon by in situ hybridization. Generally, the STC gene was not expressed uniformly in all cells of the corpuscles of Stannius. However, in cases where gene expression was uniform throughout a gland, it appeared that virtually all cells contained STC mRNA, thereby supporting the 'one cell type' hypothesis for the corpuscles of Stannius. Correlative immunocytochemistry on adjacent tissue sections indicated that cellular levels of stored hormone paralleled the distribution of STC mRNA. Stanniocalcin mRNA was undetectable in numerous other salmon tissues, thereby further supporting the notion that the STC gene is expressed exclusively in the corpuscles of Stannius.

Persistence of Acholeplasma laidlawii in an established cell line RL 19. 1. Host-parasite morphology.

The cell-parasite relationship of epitheloid cells from the established liver cell line RL 19 persistently infected with Acholeplasma laidlawii was studied by transmission electron microscopy and scanning electron microscopy. The predominantly filamentous, branched A. laidlawii were arranged horizontally on the cell surface between microvilli at the cell margin. The cell adhesion, spreading, growth pattern and cell surface shape were not altered in relation to uninfected cultures of the same cell line.

In vitro characteristics of two established hepatoma cell lines.

The in vitro behaviours of a fibroblast-like (DENA-RH 13) and an epithelial-like (DENA-RH 13A) cell line, derived from a chemically induced hepatocarcinoma of rat are described. The DENA-RH 13A can be maintained and studied either in monolayer as a transplantable solid tumor or in fluid-suspension culture as ascites tumor in Wistar rats. The cytomorphology and growth pattern of the clones of the cell lines are described. While DENA-RH 13 cells produced undifferentiated tumors with mainly sarcoma-like structures in allogeneic hosts the epithelial-like cell line (DENA-RH 13A) grew in a carcinoma-like pattern in animals.

Killing of untreated target cells by nonimmunized rat macrophages in vitro. II. Ultrastructural studies on the interaction of macrophages and rat liver cells.

The sequence of morphological changes following the interactions between macrophages of nonimmunized rats and allogeneic liver cells in vitro were examined by scanning and transmission electron microscopy. The effector cells could be identified as macrophages because of their morphologic characteristics and their ability of latex beads incorporation. The cytotoxic reactions required close contracts between the reactive cells. Effector membrane processes and microvilli attached the target cell surface. Broad contacts and, more frequent, point contacts were observed. After 4 to 5 hrs of incubation the target cells showed pinocytotic activities in the contact regions. Later on submembraneous cytoplasmatic leaks or defects indicated the increasing damage of the target cells. Finally, liver cell ghosts with degenerated organelles were found as morphologic expression of general target cell destruction whereas effector macrophages did not show any damage during the cytotoxic reaction.

[Morphological studies of triton-extracted cultured cell cytoskeleton]. / Morphologische Untersuchungen am Zytoskelett triton-extrahierter Kulturzellen.

The Coomassie Brillant Blue method of Pena (1980) was modified by use. The used method is simple and versatile for the investigation of morphological phenomena on the whole cytoskeleton of different cells in vitro. The additional advantage is the use of the specimens for the scanning electron microscopic observation after critical-point drying.

Killing of untreated target cells by nonimmunized rat macrophages in vitro. I. Studies on the type of effector cells and their capacity to destroy allogeneic target cells.

Spleen cells derived from unsensitized Wistar rats lysed untreated, allogeneic liver cells of high passages (93rd until 159th subculture) as well as allogeneic tumor cells in mixed cultures. On the other hand, rat liver cells between passages 42 and 56 and allogeneic or xenogeneic fibroblasts were not destroyed by rat spleen cells in vitro. The degree of target cell lysis was dependent on the incubation time and effector-target cell ratio. In the rat spleen, the macrophages were detected as effector cells. Rat peritoneal cells showed the same effects as rat spleen cells. Trypsin treatment caused no loss of cytotoxicity of rat macrophages. Thymocytes and blood lymphocytes of rats were not cytotoxic against allogeneic or xenogeneic target cells. The macrophages apparently destroyed target cells by a nonphagocytic form of cell contact. Unstimulated spleen cells of guinea pigs, Syrian hamsters, CBA mice and rabbits were not capable to destroy target cells in allogeneic and xenogeneic systems.