PubMed Health⌕ Search

Biomedical subjects

A Németh

Publications and source records attributed to A Németh.

At least 73 records · Page 4Linked to original sources
PubMed1990

Inhibition of potassium-induced release of histamine from mast cells by tetraethylammonium and tetramethylammonium.

In accordance with our previous results, a marked release of histamine (HA) from rat peritoneal mast cells was initiated by 150 mM KCl in the absence of extracellular Ca2+. This release could be reduced by 20-60 mM tetraethylammonium (TEA) or tetramethylammonium (TMA), the non-selective K(+)-channel blockers, Ouabain, the general inhibitor of (Na+ + K+) ATP-ase, failed to produce any changes in this release. The action of TEA discriminated between the initiation of HA release evoked by different agents, producing a blockade of the K(+)-induced but not the 48/80-stimulated HA release. In total, these data suggest the presence of TEA/TMA-sensitive K(+)-channels in the mast cell membrane and their involvement in one of the possible pathways for the initiation of HA release.

Animals↗
PubMed1989

Broncho-Vaxom inhibits histamine release from rat mast cells induced by compound 48/80 and ionophore A23187.

Broncho-Vaxom (BV) inhibited in dose-dependent manner the release of histamine from and degranulation of isolated rat peritoneal mast cells stimulated with compound 48/80 and the ionophore A23187. Inhibition persisted after removal of BV from the incubation medium before stimulation, but did not occur when bovine serum albumin (BSA) was used instead of BV. Binding of BV to mast cells was observed by electron microscopy on cells that had been incubated with colloidal-gold labelled BV. There was no significant difference between the binding of BV gold and BSA gold to the mast cells. Washing before fixation removed most of the BV gold from the cells. This study establishes BV as an in vitro histamine release inhibitor.

Adjuvants, Immunologic↗
PubMed1989

Membrane fluidity of trophoblast cells and susceptibility to natural cytotoxicity.

This study examines the relationship between membrane lipid microviscosity and susceptibility of villous trophoblast to lysis by natural cytotoxic cells. Trophoblast-enriched cell suspensions prepared from term human placentae were treated with cholesteryl hemisuccinate (CHS)--a modulator of membrane lipid microviscosity. CHS-treated cells were more susceptible targets for natural lymphocyte cytotoxicity than were untreated controls. In binding experiments, increased binding of lymphocytes to CHS-treated target cells was found. Preincubation with progesterone prevented membrane rigidification by CHS. Progesterone, cortisol, and estriol restored the impaired resistance of CHS-treated trophoblast cells to lysis. We determined microviscosity and progesterone concentration in villous surface membranes, prepared from placentae from idiopathic spontaneous abortions and normal first-trimester pregnancies. An inverse relationship was found between progesterone content and microviscosity of the membranes. Microviscosity of the membranes from abortion placentae was significantly higher (P less than .01) and progesterone concentration was significantly lower (P less than .001) than those in the membranes of normal first trimester placentae.

Abortion, Induced↗
PubMed1989

Drug metabolism in drug-induced liver diseases: pathogenetic role of active metabolites.

Three cases with drug-induced liver diseases (hepatitis caused by hydralasine, steatosis caused by methimazole, choletasis caused by birth control pill) were investigated with respect to their drug metabolising ability. Clinical diagnoses were based on the exclusion of other pathogenetic factors, on histological findings of liver biopsy specimens and on the clinical chemical tests. Investigation of biotransforming ability was carried out using test materials (menthol loading, antipyrine, sulfadimidine, caffeine, indocyanine green kinetics) and measurement of D-glucaric acid excretion. In all cases the results show a defective capacity in some respect of drug metabolism. Possible pathogenetic role of reactive metabolites is discussed in the pathomechanism of genesis of drug-induced liver diseases.

Adult↗
PubMed1988

The effect of a new antihistamine drug, Loderix (EGIS-2062), on stimulus-evoked histamine release from rat peritoneal mast cells.

The ability of a new, non-sedative antihistamine drug, Loderix (EGIS-2062), to inhibit stimulus-evoked histamine release from rat peritoneal mast cells has been investigated and compared with that of ketotifen (Zaditen). At low concentrations Loderix preincubated with the cells for 10 min prior to the addition of various stimulants (immune aggregates, ionophore A23187 and compound 48/80) produced a concentration-dependent inhibition of histamine release, while at high concentrations it induced the release of histamine. The IC50 values were calculated as 0.2, 15 and 50 microM by using immune aggregate, (rat IgG2 alpha + anti rat IgG) calcium ionophore and 48/80 as stimulants, respectively. At the IC50 level Loderix was more effective than Zaditen (100 times more effective when immune aggregate and 4 times when 48/80 were used for stimulation). Both drugs had a dual effect on mast cells. The morphological observations confirmed the pharmacological action of the drugs, showing also that the histamine release at high concentrations is due to their cytotoxic effect.

Animals↗
PubMed1987

Serum and CSF cholinesterase activity in various kinds of dementia.

The activity of acetyl- and butyrylcholinesterase was determined in serum and CSF of controls and patients suffering from different types of dementia. A statistically significant decrease in the activities of both esterases was observed in CSF of demented patients, however, primary degenerative and vascular dementia did not differ in their CSF cholinesterase levels. Compared to age-matched controls the serum butyrylcholinesterase activity was also significantly lowered in the overall dementia group. No typical serum and CSF cholinesterase isoenzyme pattern was found for dementia or any of its subgroups. It is concluded that the cholinesterase levels reflect metabolic alterations associated with dementia as a collective group but cannot be used for differential diagnosis of subgroups.

Acetylcholinesterase↗
PubMed1987

Potassium-induced histamine release from mast cells and its inhibition by ketotifen.

Potassium chloride induced a dose-dependent release of histamine from rat peritoneal mast cells at concentrations from 5 to 150 mM in the absence of extracellular Ca2+. Potassium concentrations greater than 150 mM produced less histamine release. The release was energy-dependent and was complete within one minute. The histamine liberating effect of KCl could be inhibited by NaCl and by preincubation with ketotifen. The monovalent cations, Rb+ and Cs+ also evoked histamine release, whereas Na+ and Li+ were ineffective.

Animals↗
PubMed1987

Paraquat (gramoxone) poisoning in south-west Hungary, 1977-1984. Toxicological and histopathological aspects of group intoxication cases.

Fifty-six cases of paraquat poisoning were examined during the 8 years 1977-1984. The ratio of cases of accidental to intentional ingestion of the poison was 1:1; 23.2% of the total (13/56) survived several months or years. In 1983, 11 subjects accidentally drank 10-30 ml of gramoxone; eight of 11 died in 2 weeks. Toxicological investigations demonstrated rapid elimination of poison from the blood, as well as prolonged fixation of paraquat in the lung, kidney, liver, and spleen tissues. Histological examinations showed multiorgan failure from renal tubular necrosis and pulmonary hemorrhage with alveolar epithelial injury. Pulmonary proliferative changes were present in only two cases who survived 7 and 10 days and in which artificial ventilation was utilized.

Adult↗
PubMed1986

Functional morphology of the adrenal cortex in newborns. I. Morphometric study.

Adrenal cortex of fetuses from abortion and newborns as well as 3 anencephalic monsters between 16 and 40 weeks gestational age was investigated. In order to follow the activity of adrenal cortex the volumes of nuclei and of cells were determined by means of morphometry in both the fetal and the definitive zones. The volume of cells showed correlation with gestational age only in the definitive zone. The absence of significant changes in the other (fetal) zone raises the possibility that dysfunction of the adrenal cortex and the consecutive insufficient adaptation could be made responsible for premature birth and perinatal mortality in the cases reported here.

Adrenal Cortex↗
PubMed1986

Functional morphology of the adrenal cortex in newborns. II. Morphological and biochemical analysis of lipid accumulation.

The adrenal cortex of 32 newborns and of 3 anencephalic monsters of 16 to 40 weeks' gestational age was examined. Functional activity of the adrenal cortex was followed by analysis of the zonal distribution of lipids and by measurement of the total cholesterol content. The cholesterol content ranged between 0.15 and 0.85 mg/100 g. Cholesterol accumulation was highest in the anencephalic monsters. The relative cholesterol content failed to show any correlation with gestational age. When compared with the biochemical determination of cholesterol content, morphological investigation of lipid accumulation proved to be superior and to be a suitable method for estimation of zonal maturity even in individual cases.

Adrenal Cortex↗