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Biomedical subjects

E Tabone

Publications and source records attributed to E Tabone.

At least 55 records · Page 3Linked to original sources
PubMed1985

FSH regulates cultured Leydig cell function via Sertoli cell proteins: an in vitro study.

The effects of follicular stimulating hormone (FSH) on testicular steroidogenic activity has been studied by testing the capacity of conditioned medium (CM) by both unstimulated (control) Sertoli cells (C-CM) and FSH stimulated Sertoli cells (FSH-CM) to influence porcine cultured Leydig cell activity. Leydig cells cultured in FSH-CM for 48 hrs, as compared to C-CM, show a significant (P less than 0.05) increase in [125I]-hCG binding (150% +/- 4) and hCG-stimulated testosterone (T) secretion (266% +/- 42). In addition, the stimulating effect of FSH-CM on Leydig cell function as compared to C-CM, is trypsin sensitive, non dialyzable, heat stable, acid resistant and is chromatographed following gel filtration (Sephadex G 100) into two different peaks of activity. These data suggest that FSH regulates Leydig cell function via (at least two types of) Sertoli cell secreted proteins.

Animals↗
PubMed1985

Cultured Sertoli cell-mediated FSH stimulatory effect on Leydig cell steroidogenesis.

To determine the precise role of Sertoli cells in the stimulating effects of follicle stimulating hormone (FSH) on Leydig cell activity, porcine purified Leydig and Sertoli cells were cultured separately or together in a chemically defined medium in the absence or presence of porcine, FSH 50 ng/ml. Leydig cell activity was evaluated using two parameters: human chorionic gonadotropin (hCG) binding sites; and hCG-stimulated cAMP production and testosterone secretion. First, it was found that FSH increases Leydig cell activity in crude Leydig cell preparations (40-60% of Leydig cells), whereas it exerts no effect on purified Leydig cells (greater than 90% of Leydig cells). Second, FSH stimulates the activity of Leydig cells cocultured with Sertoli cells, whereas it remains without effect on purified Leydig cells cultured alone. This stimulating effect of FSH on Leydig cell activity is dependent on the Sertoli cell number in the coculture. These data 1) show that the stimulating effect of FSH on Leydig cell function is mediated by Sertoli cells and 2) support the concept of local control of Leydig cell function originating from Sertoli cells.

Animals↗
PubMed1984

Interactions between immature porcine Leydig and Sertoli cells in vitro. An ultrastructural and biochemical study.

Interactions between Leydig and Sertoli cells, as well as a stimulatory effect of FSH on Leydig cell activity, have been reported in many studies. In order to investigate these interactions, the ultrastructure of immature pig Leydig cells under different culture conditions has been studied. When cultured alone in a chemically defined medium, there is a marked regression of the Leydig cell smooth endoplasmic reticulum and a swelling of the mitochondria. Addition of FSH or hCG does not prevent these phenomena. Co-culturing of Leydig cells with Sertoli cells from the same animal maintains the smooth endoplasmic reticulum at the level seen in vivo and in freshly isolated Leydig cells. The addition of FSH to the co-culture stimulates its development and increases Leydig cell activity, as assessed by an increase in hCG binding sites and an increased steroidogenic response to hCG. These results suggest that Sertoli cells exert a trophic effect on Leydig cells, and that the stimulatory effect of FSH on Leydig cell function is mediated via the Sertoli cells. These results reinforce the concept of a local regulatory control of Leydig cell steroidogenesis.

Animals↗
PubMed1983

[Modulation of Leydig cell activity by Sertoli cell: an in vitro study].

In vivo studies indicate that FSH can modulate Leydig cells steroidogenic activity. However, in the testis only Sertoli cells contain specific FSH receptors. In order to clarify the mechanism by which FSH exerts this effect on testicular steroidogenesis, purified Pig Leydig and Sertoli cells were cultured alone or in co-culture. Leydig cell activity has been evaluated by two parameters: 1. hCG-stimulated testosterone secretion. 2. LH/hCG binding sites. FSH does not stimulate these two parameters of purified Leydig cells when cultured alone. On the other hand, when Leydig cells are co-cultured with Sertoli cells, FSH significantly increases these two parameters of Leydig cell function. These results suggest that the effect of FSH on Leydig cells is not direct but mediated by Sertoli cells.

Animals↗
PubMed1983

Myofibroblast-like cells in non-pathological bovine endometrial caruncle.

The fine structure of the fibroblastic cells of the normal bovine endometrial caruncle was described. These cells appeared different when compared with the classical fibroblasts encountered throughout the rest of the stromal endometrium. They possess some features similar to those of myofibroblasts reported in various pathological states, to those of epithelioid fibroblasts and to those of cultured fibroblasts. However, they appeared distinct by a few other aspects. We described here the ultrastructure of these particular fibroblastic cells, as they appeared in the caruncle in vivo and under physiological conditions.

Animals↗
PubMed1981

Histopathological and ultrastructural alterations in the aorta in experimental Solanum malacoxylon poisoning.

A histopathological and electron microscopic study of the aortic wall of rabbits intoxicated with Solanum malacoxylon was performed. Histological examination showed local loss of the normal waviness of the elastic fibers and calcium deposits. Electron microscopic study of the corresponding areas showed a modified aspect of the smooth muscle cells with loss of some of their differential characteristics, especially their intracytoplasmic fibrils and densifications. The neighbouring elastic fibers showed an electron-dense peripheral band and sometimes a crystal deposit. X-ray microanalysis revealed the presence of a large amount of calcium in these crystals. Collagen fibers played no apparent role in this calcification. These findings support the idea that a local cellular alteration is necessary prior to elastic calcification. Two hypothetical mechanisms are proposed.

Animals↗
PubMed1978

Ultrastructural aspects of corneal fibrous tissue in the Scheie syndrome.

An ultrastructural study of the corneal fibrous tissue was performed in a case of Scheie's syndrome. Mucopolysaccharidosis deposits in keratocytes were observed as electron-clear and electron-dense inclusions. Modifications of the extracellular space included modifications of lamellar collagen organization and local hypertrophy of collagen bundles; presence of microfibrillar dense material isolating large irregular collagen fibers; and presence of fibrous long spacing type collagen fibers. The significance of these changes is discussed. This special form of collagen organization is supposed to appear in a modified microenvironment, that is the presence of an abnormal concentration of proteoglycans.

Biopsy↗