Occupational exposure to harmful chemical substances while processing phenol-formaldehyde resins.

Air pollutants emitted while processing phenol-formaldehyde resins have been investigated. Gas chromatography-mass-selective detection was used to separate and identify chemical compounds. It was determined that workers were exposed to formaldehyde in all workplaces. Besides, phenol, acetaldehyde, acrylaldehyde, 2-furaldehyde, xylene, ethylbenzene, toluene, tetrachlorethene, ethyl acetate, butyl acetate were found during the production of frictional materials; and 2-furaldehyde, phenol, naphthalene, 2-furanmethanol, polycyclic aromatic hydrocarbons (PAHs) during the production of abrasive materials. Quantitative analyses were performed with gas chromatography and high performance liquid chromatography. Assessment of occupational exposure indicated that chemical compounds emitted during the investigated processes might be dangerous for human health, mainly because of suspected carcinogenic compounds: formaldehyde and PAHs.

Immunofluorescent localization of the StAR protein in mitochondria of mouse Leydig cells in vitro.

The Steroidogenic Acute Regulatory (StAR) protein is assumed to enhance the rate-limiting step of the steroid biosynthesis. Now, it is the most likely candidate, responsible for acutely regulating transfer of cholesterol from the outer to the inner mitochondrial membrane. In this study, the immunoreactive StAR protein was observed in the mitochondria of mouse cultured Leydig cells stimulated by hCG andtesticular macrophage-conditioned medium. Immunocytochemistry was performed using a polyclonal rabbit antibody against the StAR protein. For selective staining of mitochondria in Leydig cells, the Mito Tracker dye was used. Computerized, superimposed images from double-fluorescence staining showed a remarkable degree of similarity in the distribution of the StAR protein and mitochondria, indicating mitochondrial localization of StAR.

Correlation between NADPH-diaphorase and iNOS in bank vole Leydig cells in vitro and in testicular sections with the use of histochemistry and immunocytochemistry.

Histochemistry for NADPH-diaphorase detects an enzymatic activity associated with nitric oxide synthase while immunohistochemistry detects the nitric oxide synthase molecule. NADPH-diaphorase and inducible isoform of nitric oxide synthase in Leydig cells in vitro and in testis sections of the bank vole were demonstrated histochemically and immunocytochemically. Histochemical studies revealed localization of NADPH-diaphorase reaction product in the cytoplasm of cultured Leydig cells as well as in the interstitial area, mainly in Leydig cells and in vascular endothelium. Distribution pattern of NADPH-diaphorase was different in Leydig cell cytoplasm of individual cells. Using immunocytochemistry, the immunoreactivity for nitric oxide synthase was observed both in cultured Leydig cells and testis sections. Moreover, a co-localization of positively immunostained cells with those histochemically detected was noticed. Addition of hCG to the cultured medium or injections in vivo resulted in a small decrease in reaction intensity in Leydig cells. Treatment with N omega-nitro-L-arginine methyl ester resulted in distinctly weaker reactivity of the enzymes studied which was correlated with a higher testosterone and estradiol levels in Leydig cells measured radioimmunologically. The results have indicated that nitric oxide synthase is able to act directly within the male gonad regulating androgen secretion by Leydig cells.

Gas-chromatographic determination of chlorostyrene and dichlorostyrene isomers in workplace air.

Conditions for a gas-chromatographic determination of vapors and aerosols of p-chlorostyrene and 2,6-dichlorostyrene contained in workplace air samples were determined. The method is based on the adsorption of p-chlorostyrene and 2,6-dichlorostyrene on activated charcoal and fiberglass, desorption with toluene and analysis of the obtained solution by capillary gas chromatography with flame ionization detection (FID). The determination limit of the method is 5 mg m(-3) for each substance.

[Immuno-endocrine interactions in the testis: possible involvement of Ca2+ in signal transduction pathway in Leydig cells]. / Badanie immuno-endokrynnych zaleznosci w gonadzie meskiej: udzial jonów wapniowych w stymulacji komórek Leydiga in vitro.

The testis is divided, both functionally and anatomically, into two specialised compartments, i.e. the vascular interstitial tissue and avascular seminiferous tubules. Leydig cell steroidogenesis is mainly controlled by luteinizing hormone (LH) secreted from the anterior pituitary. It is well known that LH is able to generate second messengers by adenylate cyclase and the cycle of inositolphospholipids. Also Ca2+ ions are taken into account as an important modulators of Leydig cell steroidogenesis. The aim of this study was to show the effect of macrophage-conditioned medium on the basal and LH stimulated testosterone secretion by mouse Leydig cells in vitro. A source of Leydig cells was the testis of mature, Swiss strain mice. Leydig cells were isolated and cultured for 48 hrs. Testosterone levels were measured radioimmunologically. Intracellular free Ca2+ ions were analysed by computer automatic system 'MAGICAL'. Results indicated that not only LH but also macrophage-conditioned medium were able to modulate testosterone secretion by Leydig cells and increase intracellular calcium concentration. Therefore, it seems possible that the action of proteins secreted from macrophages is mediated through Ca2+ ions which are involved in another signal transduction pathway leading to stimulation of testosterone biosynthesis by Leydig cells in vitro.

Mouse Leydig cell culture on microcarriers.

Culturing cells on microcarriers maximizes the ratio of surface area to culture medium volume. The aim of this study was to show microcarrier culture as a useful tool for improvement of steroidogenic activity in mouse Leydig cells. Freshly isolated cells were grown on Sephadex microcarriers, Cytodex 3, and gelatin beads (gelaspheres) that were uncoated, coated with collagen or coated with fibronectin. The cells were cultured in control or LH-supplemented medium. The effect of LH on testosterone and estradiol secretion was studied with appropriate radioimmunoassays. The activity of hydroxysteroid dehydrogenases (3 beta-HSD, 17 beta-HSD) was evaluated histochemically. Leydig cells growing on microcarriers formed colonies. The strongest response to luteinizing hormone stimulation was observed on gelatin beads coated with fibronectin and collagen. In cells growing on a fibronectin layer, very strong activity of 3 beta-HSD and 17 beta-HSD and an increase in steroid hormone levels were observed. Basal and LH-stimulated testosterone and estradiol secretion were all much higher in the microcarrier than in the monolayer culture system. We conclude that Leydig cells maintain differentiated functions more efficiently on collagen- and fibronectin-coated gelasperes than on Sephadex microcarriers and that uncoated gelaspheres are less efficient than coated ones. Pure gelaspheres are unsuitable for improvement of the hormonal and enzymatic activity of Leydig cells.