Biomedical subjects

G M Roomans

Publications and source records attributed to G M Roomans.

202 records · Page 12Linked to original sources

PubMedDate not supplied

Cryoultramicrotomy as a preparative method for x-ray microanalysis in pathology.

The role of ion shifts in cell injury has become one of the most intriguing fields of application of X-ray microanalysis in pathology. In principle, cryo(ultra)-microtomy is the best preparative method for X-ray microanalysis of diffusible substances. In this review, the following points are discussed: the choice of freezing method and coolant, the use of high molecular weight polymer cryoprotectants and their possible physiological effects the choice of the cryosectioning temperature, and techniques for handling and transfer of sections. Experiences with the sectioning of cryoprotected tissue are presented. Finally, other preparative techniques for microanalysis are compared to cryoultramicrotomy.

Animals↗

PubMedDate not supplied

The reserpinized rat in the study of cystic fibrosis: x-ray microanalysis of submandibular gland and pancreas.

The chronically reserpinized rat has been suggested as an animal model for cystic fibrosis. X-ray microanalysis of thick and thin cryosections was carried out to assess elemental redistribution in the submandibular glands and the pancreas of reserpinized rats at the cellular and subcellular level. In the submandibular gland of reserpinized rats, calcium and magnesium concentrations were significantly elevated. Mucus globules, secretory granules, and endoplasmic reticulum were the primary sites of the localization of excess calcium and magnesium. A significant potassium loss from the gland had occurred, particularly from the serous cells. Electron microscopy of conventionally prepared tissue showed marked swelling of the endoplasmic reticulum, especially in mucous cells. The elemental changes in the pancreatic acinar cells of reserpinized rats were reminiscent of elemental redistribution connected with cell death: increased levels of sodium, chlorine, and calcium and decreased levels of magnesium and potassium. Ultrastructural changes included swelling of the endoplasmic reticulum and obstruction of the acinar lumen. It is concluded tha elemental redistribution in chronically reserpinized rats presents interesting parallels with cystic fibrosis.

Animals↗

PubMedDate not supplied

X-ray microanalysis of epithelial cells in culture.

X-ray microanalysis of cultured cells can be used to study ion transport properties of epithelial cells in vitro. A method was developed to culture a variety of epithelial and secretory cells (colon cancer cells, insulinoma cells, sweat gland epithelium, bovine mammary epithelium). The cells were grown on Formvar-film covered titanium grids, rinsed, frozen, and freeze-dried. The cultures of colon cancer and the bovine mammary epithelial cells appeared to contain two subpopulations of cells with different elemental composition. cAMP-mediated chloride secretion could be studied in the colon cancer cells and the cultured sweat gland epithelium: the cellular content of chloride decreased after stimulation with cAMP or with substances that increase the cellular level of cAMP.

Animals↗

PubMedDate not supplied

Structural and functional studies of gap junctions in human myometrium.

Gap junctions are of importance in the coordinated contraction of uterine smooth muscle during labor. There are indications that in the human myometrium, gap junctions are much more numerous in the period immediately surrounding parturition. The presence and the functional state of gap junctions in human myometrium was studied by electron microscopical morphometry and by studying the distribution of an injected fluorescent dye. Electron microscopy showed that the number and size of gap junctions was significantly higher during the active phase of labor than during the pre-labor phase. Pressure injection of Lucifer Yellow into myometrial cells in vitro showed only weak coupling in the pre-labor stage. These data support the notion that coupling between myometrial cells develops in immediate association with parturition.

Female↗