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Z Somosy

Publications and source records attributed to Z Somosy.

33 records · Page 2Linked to original sources
PubMed1988

Effect of X-irradiation on adenylate cyclase activity and cyclic AMP content of primary human fibroblasts.

Ionizing radiation provokes an increase of the cAMP level in several organs and body fluids. After reviewing the relevant literature we present the results of our own experiments on primary human fibroblasts. X-irradiation at doses of 0.5 and 2.5 Gy in vitro evoked a rapid and reversible increase of adenylate cyclase enzyme activity. A significant increase in cAMP level of these cells was also observed. Adenylate cyclase was usually localized basolaterally on the surface of unirradiated cells, while irradiation resulted in a modification of distribution, i.e., the enzyme activity also appeared in apical localization.

Adenylyl Cyclases↗
PubMed1987

The effects of low doses of ionizing radiation upon the micromorphology and functional state of cell surface.

The cellular membrane as one of the targets of ionizing radiation might play an important role in the development and modification of radiation-induced alterations after low doses. The present paper reviews the micromorphological and functional changes of plasma membranes of irradiated blood and cultured cells with special emphasis on the surface conditions: lectin binding, negative surface charges. The review is completed by our own studies on distribution of positive surface charges and the bindings of two lectins, the Concanavalin A and the wheat germ agglutinin. It was found that the decrease of negative surface charges is unconcomitant with appearance of domains exposing positive ones, particularly on the surfaces of rufflings. The distribution of Concanavalin A binding sites turned from a uniform distribution to a polarized one, especially on apical regions where it appeared in large aggregates. The polarity in localization of wheat germ agglutinin on untreated fibroblasts observed in our experiments ceased shortly after irradiation.

Animals↗
PubMed1986

Radiation-induced changes of negative charge on the cell surface of primary human fibroblasts.

By binding cationized ferritin (CF) to the plasma membrane of primary human fibroblasts, the amount and topology of negatively charged sites on cell surfaces were studied after X-irradiation. The CF binding was tested both on fixed and unfixed cells. Using various enzymes, the chemical nature of sites carrying the negative charges on cell surfaces was investigated. The results suggest that in unirradiated fibroblasts the CF binding occurred in a polarized manner, i.e. the particles were localized mainly on the apical surface of cells and formed clusters. The thin cytoplasmic protrusions and cell-to-cell contact sites bound CF to a greater extent than the bleb-like formations. Enzymatic digestion of surface polysaccharides showed that the main carriers of negatively charged sites are the glycosaminoglycans associated with the cell surface. The fixation of cells with glutaraldehyde did not influence the topology of CF binding either before or after the enzymatic treatment. After X-irradiation with 2.5 Gy the topology of CF binding did not change but the CF coverage of cells as well as the amount of ferritin particles per unit of surface area decreased within 10 min. The changes proved to be reversible as the values reached the pre-irradiation level by 1 h after irradiation.

Cell Membrane↗
PubMed1985

Cytomorphological changes of murine lymphocytes under the effect of fission neutrons.

The cytomorphology of murine lymphocytes was examined with transmission and scanning electron microscopy after fission neutron irradiation in the dose range of 0.5-4.5 Gy. The micromorphology of the cell surface changed significantly: the villous cell surface characteristic of lymphocytes became smooth. Cytoplasmic protrusions of various sizes and shapes appeared. In addition to the changes on the cell surface, alterations in cytoplasmic organelles and nuclear membranes were also observed. Even the forms of the nuclei had changed, the nucleoli were often segregated and at several sites accumulation of nuclear bodies was evident.

Animals↗
PubMed1984

Biological effect of He-Ne laser: investigations on functional and micromorphological alterations of cell membranes, in vitro.

A 1-J/cm2 dose of single laser-irradiation applied on primary human embryo fibroblast culture was not followed either by functional or micromorphological alterations of cell surfaces. This dose, however, applied four times with 24-hour intervals changed the functional conditions as well as surface charges of cell membranes. As detection methods, radioactive glucosamine uptake, lectin, and cationized ferritin-binding techniques were applied. At the same time, the scanning and transmission electron microscopy of laser-irradiated cells did not reveal any micromorphological or ultrastructural alterations. The effect of a 5-J/cm2 dose did not differ from that of 1 J/cm2. It is suggested that laser radiation-induced circumstances on cell surfaces can contribute to the strength of cell-to-cell contacts, i.e., to the stimulation of epithelization experienced in the clinical gynecologic practice.

Cell Membrane↗
PubMed1984

Effects of mixed neutron-gamma irradiation in vivo on the cell surfaces of murine blood cells.

For studies on cell membranes, mice were exposed to mixed neutron + gamma reactor-radiation in the range of total doses from 0.5 to 4.5 Gy. Changes in functional activity of plasma membranes of erythrocytes, platelets, and lymphocytes were followed by a lectin-binding technique at various intervals afterwards. The amount of 3H-concanavalin A bound to cells altered considerably during the 1st h after irradiation in all cell types. Lymphocytes and platelets, however, were more sensitive than erythrocytes as increased lectin-binding could already be observed after 0.5 Gy. The binding ability of these cells performed oscillatory behaviour. In addition, alterations in shapes and ultrastructure of cell surfaces and intracellular membranes were observed.

Animals↗
PubMed1984

Cell membrane polarity in primary human fibroblasts.

The topologies of bindings of cationized CF and native ferritin (NF) on plasma membranes of primary human fibroblasts were examined by transmission electronmicroscopy. Both ligands bound mainly to apical surfaces and less abundantly to lateral regions. At basal localization they were observed only at cell-to-cell connections. The polarity of negatively charged binding sites was not altered by glutaraldehyde fixation. The definite polarity of plasma membranes of cultured cells express alternating surface areas charged negatively or positively.

Binding Sites↗
PubMed1982

Effect of endotoxin and radio-detoxified endotoxin on cell membranes in vitro.

The effect of parent lipopolysaccharide (LPS) and radio-detoxified endotoxin (rdLPS) on various human blood cell membranes proved to be different as detected by 3H-concanavalin A-binding technique in vitro. The lectin-binding ability of erythrocyte membranes did not change upon treatment by either endotoxin, whereas that of lymphocytes was stimulated by LPS at 10-50 micrograms/ml concentration as well as by rdLPS at the lowest dose applied, i.e. 0.1 micrograms/ml. The LPS-treated platelets bound 3H-concanavalin A less than did the untreated controls; on the other hand, the rdLPS did not change the lectin-binding surface of these cells. The affection by radiation of cell membranes could be prevented by pretreatment with endotoxins. This fact, however, could not be considered a radioprotective effect. The micromorphological investigations by scanning electron microscopy (SEM) support our data concerning the functional alterations of plasma membranes of platelets and lymphocytes after LPS and rdLPS treatment as well as after the combined effect of endotoxin pretreatment and X-irradiation, since a severe smoothening of the cell surface could be observed.

Blood Platelets↗
PubMed1978

Study of the antitumoral activity of S-carbamoyl-L-cysteine derivatives in animal experiments.

The antitumoral activity of three amino acid derivatives, S-carbamoyl-L-cysteine, S-ethyl-carbamoyl-L-cysteine, and S-chloroethyl-carbamoyl-L-cysteine, was studied. The ethyl and chloroethyl derivatives had a pronounced curative effect on certain animal tumors. It is interesting in the case of S-carbamoyl-L-cysteine that N-ethylization of the substance resulted in increased chemotherapeutic effectivity with no simultaneous change of the toxicity. According to various studies this effect is different in many respects from that of the known cytostatics, and a possibility of a specific selective or surface activity is raised.

Animals↗
PubMed1975

[Globular corpuscles in hepatomas of Swiss mice].

In hapatomas formed spontaneously without cirrhosis at Swiss mice numerous globular corpuscules of eosinophil character were found. These corpuscules as revealed by electron microscopy are formed in cyternas of the rough surfaced endoplasmatic reticulum and are of the nature of protein.

Animals↗