Biomedical subjects

Z Nemes

Publications and source records attributed to Z Nemes.

11 recordsLinked to original sources

PubMed1992

Differentiation markers in hemangiopericytoma.

Normal pericytes were found to express factor XIIIa (F-XIII) and histocompatibility antigen HLA-DR. These markers were studied in 15 hemangiopericytomas (HPC) and 16 other tumors with an HPC-like pattern. A subpopulation of tumor cells expressing F-XIII and HLA-DR antigens was a constant feature of HPC and supported their pericytic origin. Meningeal HPC did not differ in phenotype from peripheral soft tissue HPC. Most tumors with an HPC-like pattern (including synovial sarcomas, malignant schwannomas, leiomyosarcomas, and liposarcomas) were negative for F-XIII and HLA-DR. Malignant fibrous histiocytomas, however, invariably contained a subpopulation expressing these antigens. Therefore, F-XIII can be considered as a marker of fibrohistiocytic differentiation in HPC. Individual tumor cells in HPC occasionally were positive for factor VIII-related antigen (F-VIII-R-Ag), suggesting that the spectrum of differentiation in HPC may include the endothelial cell line. The differentiation characteristics of HPC support the concept that pericytes are primitive cells that may act as precursors to other mesenchymal cells.

Antigens, Differentiation↗

PubMed1992

Fibrohistiocytic differentiation in capillary hemangioblastoma.

Seven cases of capillary hemangioblastoma from the cerebellum and spinal cord were studied by immunohistochemical methods to determine the origin of the stromal cells. A subpopulation of factor XIIIa-positive tumor cells was a constant feature in hemangioblastomas. These stellate or spindle-shaped cells transformed into typical vacuolated stromal cells. Factor VIII-related antigen was limited to the vascular endothelium. Glial fibrillary acidic protein was present only in entrapped astrocytes. Staining for alpha-1-antitrypsin (alpha 1AT) and alpha-1-antichymotrypsin (alpha 1 ACT) was occasionally observed in stromal cells. It was concluded that the factor XIIIa-positive stromal cells in capillary hemangioblastoma indicate fibrohistiocytic differentiation, which is part of the differentiation spectrum of hemangiopericytomas.

Adult↗

PubMed1979

The pharmacological relevance of vital staining with neutral red.

The uptake of neutral red into the renin-containing juxtaglomerular granules does not inhibit the release of renin either in basal or in stimulated states of renin secretion. The vasodilating effect of neutral red may be due to a nonspecific binding to noradrenaline-receptors in the vascular smooth muscle cells.

Angiotensin II↗

PubMed1978

Organotoxic effects of excessive doses of sodium nitroprusside in the rabbit.

The simultaneous iv. infusion in conscious rabbits of 7.5 mg/kg.h sodium nitroprusside (SNP) plus sodium thiosulfate in the molar ratios 1:5 or 1:10, respectively, for 4 h produced perilobular necroses of liver cells. 21 days after the infusion, regeneration of the damaged cells was complete. No histological changes were found in various other organs after this high dose of SNP. No signs of liver toxicity were found in rabbits that had received 0.75 mg/kg.h SNP for 8 h daily during a period of 5 consecutive days. This dose was in the range of SNP doses recommended for clinical use in human patients. Nevertheless we suggest that apart from the thiocyanate plasma levels, also the GOT, GPT, and gamma-GT concentrations in blood be controlled, especially when high doses of SNP are to be given for prolonged periods in order to exclude possible hepatotoxic effects of SNP.

Alanine Transaminase↗

PubMed1978

[Cementoma].

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Cementoma↗

PubMed1976

Polarization microscopic evidence for an oriented cytoplasmic structure in the "dark" variants of adrenalin-storing cells.

A diffuse cytoplasmic birefringence confined to "dark" adrenalinstoring cells has been described. The main optical characteristics of the birefringence factor include: regular orientation of birefringence relative to the base-apex axis of cells; additive anisotropic staining with methods based on the principle of topo-optical staining reactions; dependence of birefringence on labile morphologic properties. On the basis of the capacity of the macromolecular matrix of chromaffin granules to form lamellar liposomal structures in vitro it has been proposed that a reorientation of molecular organization in the matrix of chromaffin cells is responsible for the observed optical phenomenon. The direction of birefringence was explained by a preferential direction of contractile forces acting during "dark" cell formation.

Adrenal Medulla↗

PubMed1976

Light- and electron-microscopic studies on the formation of "dark" variants of chromaffin cells in the rat adrenal medulla.

"Dark" cell formation has been studies in the adrenal medulla with combined light- and electron-microscopic methods. Correlation between light- and electron-microscopic appearance has been demonstrated. It has been pointed out that the formation of "dark" cell artefact can be prevented during immersion fixation and can be produced also during perfusion fixation by appropriate physical conditions. "Dark" cell formation was elicited by prefixation cooling and/or by increased tissular pressure. The nature of the underlying physicochemical change was interpreted as a uniformly distributed sol-gel transition of cytoplasmic macromolecules. The formation of cytoplasmic gel structures can be considered an endothermic process which involves volume increase (+ deltaV) - as may be inferred by their susceptibility to solation by high pressure and low temperature.

Adrenal Medulla↗

PubMed1976

Evidence for lysosomal matrix in the juxtaglomerular cell granules.

A systematic histochemical analysis of the matrix composition of juxtaglomerular cell granules was carried out. The behaviour of kidney lysosomes under similar conditions has been examined in parallel. The tubular protein droplets produced by the i.p. administration of egg albumen were chosen as lysosome-model. Identical pattern of histochemical reactions has been demonstrated both in kidney lysosomes and juxtaglomerular granules indicating the presence of separate lipoprotein and glycoprotein components. The ammoniated silver carbonate method for lysosomes was also positive in juxtaglomerular cell granules. These results support on a non-enzymatic basis the concept that secretory granules and lysosomes are evolutionary homologues.

Animals↗

PubMed1976

Does the renin-angiotensin system contribute to the vascular lesions in renal hypertensive rats?

1. Renal hypertensive rats with a normal or suppressed activity of the renin-angiotensin system develop vascular lesions which are similar to those observed in spontaneously hypertensive rats on high sodium diet. 2. Exposure of a vascular bed to high blood pressure results in a rapid damage of the vascular wall, irrespective of the state of the renin-angiotensin system.

Angiotensin II↗

PubMed1976

The cytoarchitecture of the adrenal medulla in the rat.

The disposition of adrenaline and noradrenaline storing cells in the adrenal medulla has been studied in the rat. It has been demonstrated that no morphological or functional reason exists for the follicular designation of clumps of chromaffin cells in the medulla. No significant difference was found between the outer and inner zone as regards the frequency of NA cells by morphometric and statistical methods. The cytoarchitectural differences between adrenaline- and noradrenaline-storing cell arrangement are described. Special features of the interrelation between noradrenaline storing cells, cortical cells and the connective tissue framework are stressed. The light and electron microscopic appearance of two types of cortical cells, assumed to represent different states of functional activity is described.

Adrenal Medulla↗

PubMed1975

Morphological examination of the juxtaglomerular apparatus following the fluorescence microscopic demonstration of sympathetic nerves.

Several catecholamine demonstrating fluorescence techniques based on the formaldehyde-condensation principle have been examined for the possibility of application of juxtaglomerular granulum demonstrating methods. Freezing and thawing cause a distruption of juxtaglomerular granules. Short formalin fixation does not prevent this damage. Juxtaglomerular granules were successfully stained after freeze-drying. The adaptation of Endes's trichrome method on the basis of the classical catecholamine technique of Falck and Owman resulted in a reliable practical method. Procedures introduced into the trichrome methods to increase the colour and intensity contrast of the staining of juxtaglomerular granules and to stain the elastic membranes are described. Some aspects of the staining mechanism of juxtaglomerular specific granules are also discussed.

Animals↗