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A Németh

Publications and source records attributed to A Németh.

At least 55 records · Page 3Linked to original sources
PubMed1998

GABA-immunohistological observations, at the electron-microscopical level, of the neurons of isthmic nuclei in chicken, Gallus domesticus.

Following a demonstration of Golgi-impregnated neurons and their terminal axon arborization in the optic tectum, the neurons of the nucleus parvocellularis and magnocellularis isthmi were studied by means of postembedded electron-microscopical (EM) gamma-aminobutyric acid (GABA)-immunogold staining. In the parvocellular nucleus, none of the neuronal cell bodies or dendrites displayed GABA-like immunoreactivity in EM preparations stained by postembedded GABA-immunogold. However, numerous GABA-like immunoreactive and also unlabeled terminals established synapses with GABA-negative neurons. GABA-like immunoreactive terminals were usually found at the dendritic origin. Around the dendritic profiles, isolated synapses of both GABA-like immunoreactive and immunonegative terminals established glomerulus-like structures enclosed by glial processes. All giant and large neurons of the magnocellular nucleus of the isthmi displayed GABA-like immunoreactivity. Their cell surface was completely covered by GABA-like immunoreactive and unlabeled terminals that established synapses with the neurons. These neurons are thought to send axon collaterals to the parvocellular nucleus; their axons enter the tectum opticum. The morphological characteristics of neurons of both isthmic nuclei are like those of interneurons, because of their numerous axosomatic synapses with both asymmetrical and symmetrical features. These neurons are not located among their target neurons and exert their modulatory effect on optic transmission in the optic tectum at a distance.

Animals↗
PubMed1998

A gene encoding a liver-specific ABC transporter is mutated in progressive familial intrahepatic cholestasis.

The progressive familial intrahepatic cholestases (PFIC) are a group of inherited disorders with severe cholestatic liver disease from early infancy. A subgroup characterized by normal serum cholesterol and gamma-glutamyltranspeptidase (gammaGT) levels is genetically heterogeneous with loci on chromosomes 2q (PFIC2) and 18q. The phenotype of the PFIC2-linked group is consistent with defective bile acid transport at the hepatocyte canalicular membrane. The PFIC2 gene has now been identified by mutations in a positional candidate, BSEP, which encodes a liver-specific ATP-binding cassette (ABC) transporter, sister of p-glycoprotein (SPGP). The product of the orthologous rat gene has been shown to be an effective bile acid transporter in vitro. These data provide evidence that SPGP is the human bile salt export pump (BSEP).

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1995

[Molecular genetic markers of Alzheimer dementia].

Alzheimer's dementia (AD) is a progressive neurodegenerative disease which is one of the most common forms of dementia in the above 65 years old age group. Diagnosis is based upon evaluation of cognitive skills, elimination of other dementia associated diseases and on cranial CT examination. However, definitive diagnosis is proved only by neurohistological findings. The etiology of the disease is unknown and effective treatment is not available. Intensive research into the pathomechanism of the disease revealed a connection between increased frequency of apolipoprotein E4 allele and later onset of AD. The aim of the author's research was to characterize apolipoprotein E polymorphisms in AD patients and to examine immunological factors which could play an important role in the development of the disease such as the polymorphism of complement and lipoprotein(a) [Lp(a)] alleles previously had not been investigated. 35 AD patients (26 female, 9 male) were examined (mean age 66.4 years +/- 8.7 SD). 18 of these patients showed late onset of the disease. The E4 allele was significantly more frequent in both early and late onset groups compared to controls (0.29 vs. 0.14 and 0.33 vs 0.09). The high frequency of apo E4 found in the early onset group in this study differs from other international data. Serum lipid, lipoproteins, Lp(a) concentrations and Lp(a) phenotype distribution showed no significant difference compared to controls. Furthermore, it was found that the frequency of complement C4AQ0 (null) and Bf F alleles was higher in the late onset AD group compared to controls (0.35 vs 0.139 and 0.305 vs. 0.225) suggesting an active involvement of the complement system in the pathogenesis of this disease.

Age Factors↗
PubMed1995

[Helicobacter pylori in benign gastroduodenal diseases].

(A light- and electronmicroscopic study). We have examined the occurrence of Helicobacter pylori (HP) in 2937 gastric antral biopsy specimens from 979 patients with upper gastrointestinal symptoms. The incidence of HP proved to be 50.5%. The endoscopic diagnoses were: gastritis (62 cases), gastric erosion (425), gastric ulcer (51), duodenitis (22), duodenal erosion (119), duodenal ulcer (122) and the HP incidence was 29, 46, 63,, 50, 66 and 73%, respectively. Microscopic findings were: chronic gastritis (442), chronic active gastritis (356) and normal mucosa (181). The prevalence of HP in these groups was 43%, 78% and 11%, respectively. The activity of gastritis was in good correlation with HP infection. We did not see epithelial damage, and found only a few instances of mucus depletion. Electronmicroscopic examination was performed in order to investigate the morphology of bacterium and its relation to the mucosal cells. We observed mild loss of microvilli on the cell surface and did not see any cell invasion by bacteria.

Adolescent↗
PubMed1995

Some data on connections of neurons of nuclei isthmi of the chicken.

After PhA-L injection into the tectum opticum of chickens, column-like labelled terminal arborizations were found in tectum and also labelled neurons of Ipc and Imc in the corresponding sections. The PhA-L labele proved the projection from both Imc and Ipc neurons to tectum; their terminal axonarborizations were clearly discernible. Column-like terminal arborizations of different sizes were found both in PHA-L and Golgi impregnated preparations. GABA immunostaining displayed GABA positive neurons in Imc. The EM-Golgi study corroborated that the axon-terminals of Imc neurons established symmetrical synapses in the tectum. The results of the present study support the existence of an inhibitory feedback loop from Imc neurons to the tectum.

Animals↗
PubMed1994

[Effect of Gevilon therapy and its relation to E polymorphism].

Our clinical trial was set out to estimate the apoE allele frequency by way of polymerase chain reaction and restriction enzyme isoform genotyping amongst 81 obese, hyperlipoproteinemic patients (treated with gemfibrozil + diet). The relative frequencies of the E2, E3, E4 alleles were 0.28, 0.61, 0.11 respectively (according to the Hardy-Weinberg equilibrium). Phenotypes with increased triglycerides levels were dominant in both sexes: IV + V > II/B > II/A (44.4%, 39.5%, 16.0%). Therapy significantly decreased the atherogen lipid values with differing efficacy among each genotype group: E3 > E4 > E2. Our findings demonstrate that in the II/A group there was no great change using the gemfibrozil + diet combination: whereas in IV + V group this combination was effective in each apoE isoform. In the case of II/B it is highly important to determine the apoE genotypes, because the therapy is only efficacious in the E33 group taking all lipid parameters into consideration.

Adult↗
PubMed1994

Dynamism of cytoprotective and antisecretory drugs in patients with unhealed gastric and duodenal ulcers.

A continuous multiclinical, randomized and prospective study has been carried out in our department to compare the efficacy of different cytoprotective (sucralfate, DE-NOL, Vitamin A) and antisecretory drugs (atropine, cimetidine, ranitidine, famotidine, pirenzepine) on ulcer healing in patients with chronic gastric ulcer (GU) and duodenal ulcer (DU). A total of 441 patients were randomized in different groups. The patients were treated with atropine (1 mg/day), cimetidine (1000 mg/day), ranitidine (300 mg/day), famotidine (80 mg/day), pirenzepine (50 mg/day), sucralfate (1000 mg/day), Vitamin A (3 x 50,000 IU/day) alone or in combination with cyproheptadinum (3 x 4 mg/day) DE-NOL (3 x 5 mL/day) and Tisacid (Al-Mg-hydroxycarbonicum; in different doses). Endoscopy (planimetric evaluation of ulcer sizes), measurements of clinical changes in patients' complaints, antacid consumption and laboratory tests (blood counts, urine, kidney and liver functions, electrolytes, pH status) were carried out at the beginning and 2, 4 and 6 weeks after treatment with different drugs. The incidence of ulcers, changes of ulcer sizes, subjective pain score and antacid consumption were noted at the abovementioned times. There were 20 or more patients in each group. The dynamism of ulcer healing rate was studied on the unhealed GU and DU. Our results showed that the ulcer size decreased significantly in all groups in GU and DU patients treated with cytoprotective and antisecretory drugs. Summed pain score (expressed as per cent of basic values) and antacid consumption decreased significantly in all groups. As well, some differences were found in the dynamism of ulcer healing at 2 weeks after the treatment.(ABSTRACT TRUNCATED AT 250 WORDS)

Antacids↗
PubMed1994

Phaseolus vulgaris lectin labelled and GABA immunogold stained terminals in nucleus rotundus. An EM study.

Having injected Phaseolus Vulgaris Lectin (PhA-L) iontophoretically to subpretectal (SP) and postero-ventralis (PV) thalamic nuclei, labelled fibers and terminals appeared in nucleus rotundus (Rt). The PhA-L immunostained fibers are divided dichotomically and they develop long terminal sections with large varicosities. In EM preparates PhA-L labelled terminals were observed establishing axo-somatic, axo-dendritic symmetrical synapses. These terminals were stained by GABA immunogold procedure and proved to be GABA-ergic, i.e. the neurons of SP and PV nuclei supply the principal neurons of Rt with GABA positive terminals, which are located on specific, exponent loci of the principal neuron.

Animals↗
PubMed1993

EM study on Phaseolus vulgaris lectin labelled terminals of rotundal fibers and on GABA immunogold stained structures in chicken ectostriatum centrale.

After having iontophoretically injected Phaseolus vulgaris Lectin into nucleus rotundus, labelled terminals were examined in ectostriatum centrale by EM. These terminals contained round synaptic vesicles. They were observed earlier by Golgi method and proved to be of rotundal origin by Phaseolus Lectin tracing method. The labelled terminals establish synapses, on large and small dendritic truncs of projection and local circuit neurons, and also contact spines and dendritic processes of projection neurons. They were observed on soma of GABA immunopositive local circuit neurons, and also on dendrites. Some observations completed the already known data on fine structure of the chicken ectostriatum centrale.

Animals↗
PubMed1992

Quantitative immuno-gold labelling and ultrastructural preservation after cryofixation (combined with different freeze-substitution and embedding protocols) and after chemical fixation and cryosectioning. Analysis of the secretory organelle matrix of Paramecium trichocysts.

Among the variety of parameters affecting immuno-gold labelling efficiency, mainly the effects of different preparative protocols were tested. Preservation of ultrastructure and of antigenicity are the salient features of this study. We have labelled insoluble components of the secretory matrix of Paramecium trichocysts with specific antisera, using 10 nm colloidal gold particles. The highest labelling efficiency was obtained with fast freezing (cryofixation, either by sandwich or spray-freezing), freeze-substitution in methanol (without added fixatives) and hydrophilic Lowicryls, particularly when applied at low temperatures (K11M at 193 K). The presence of different chemical fixatives always reduced the labelling density and some recommendations from the literature do not appear advisable. Methods commencing with fixation at greater than or equal to 0 degree C, such as "progressive lowering of temperature" (PLT) or preparation of cryostat sections, i.e. with chemical pretreatments, always resulted in lower labelling density. Our data appear, therefore, relevant for optimal immuno-gold labelling of insoluble antigens and emphasize the potential of cryofixation as a primary preparation step. In addition, ultrastructural preservation was also superior after cryofixation.

Acrylic Resins↗
PubMed1992

Mechanisms of vagal nerve in gastric mucosal defense: unchanged gastric emptying and increased vascular permeability.

Gastric cytoprotection in response to different agents (prostaglandins, carotenoids, etc.) failed to occur after surgical vagotomy. Decreased gastric emptying and the increased vascular permeability were tested in ethanol-treated rats without and with bilateral surgical vagotomy. The experiments were carried out on Sprague-Dawley rats. The animals were fasted for 24 h before experiments. Bilateral surgical vagotomy or only laparatomy were carried out at 30 min before administration of ethanol (96%, 1 ml). The animals were killed at 0, 1, 5, 15, and 60 min after ethanol administration, when the number and severity of gastric mucosal lesions were noted. In another series of experiments, the animal received Evans blue (1 mg/100 g) i.v. 15 min before killing. The gastric contents were collected and the glandular mucosa was scraped. Evans blue was extracted in chloroform, and its concentration was spectrophotometrically measured. It has been found that (a) both number of lesions and severity of ethanol-induced gastric mucosal damage were larger at each time period in surgically vagotomized rats than in rats with intact vagal nerves; (b) the increased vascular permeability was significantly higher in gastric mucosa at an early period in surgically vagotomized rats compared to rats with intact vagal nerve; (c) the increased vascular events preceded the development of macroscopic appearance of gastric mucosa damage in both groups of animals; and (d) the time-related responses were the same in both groups of animals. It is concluded that increased vascular permeability, but not gastric emptying, probably has some role in the failure of the development of gastric cytoprotection in surgically vagotomized rats.

Animals↗
PubMed1992

Some data on GABA-ergic innervation of nucleus rotundus in chicks.

The EM preparates displayed in the nucleus rotundus also symmetrical type of synapses with flattened vesicles, known this type as inhibitory synapsis. To prove this supposition and to find the sources of inhibitory terminals GABA-immunostaining was applied in the diencephalon of chicks. The preparates were examined by light- and electronmicroscope. In nucl. rotundus the large terminal profiles on the cell membrane of principal neurons, on the dendrites and branching areas of terminal branchings of dendrites proved to be GABA positive. The sources of GABA-ergic fibers seemed to be the subpretectal and ventral posterior thalamic nuclei.

Animals↗
PubMed1991

Effect of phototherapy on 3H-imipramine binding sites in patients with SAD, non-SAD and in healthy controls.

The effect of incandescent light treatment on the density of 3H-imipramine binding sites (Bmax) was investigated in 17 patients with seasonal affective disorder, in eight patients with non-seasonal depression and in six healthy volunteers. A significant increase in mean Bmax value parallel to a marked improvement of the depressive symptoms was found only in patients with SAD. No effect was observed either on mean Bmax value or on clinical symptoms in patients with non-SAD and on mean Bmax value in healthy volunteers.

Adult↗
PubMed1991

Effects of photosensitization and low-power helium-neon laser irradiation on liposomes and cell membranes.

Low-power He-Ne laser irradiation causes a well-defined and energy dependent cell destruction of in vitro cultured cell lines sensitized by hematoporphyrin derivative (HPD). The mechanism of this photosensitization was studied by measuring with polarization microscopic, scanning electron microscopic, and electron-spin-resonance (ESR) spectroscopic parameters. The cell damage caused by photosensitization and laser irradiation seems to be a complex process, however the biological membranes seem to be one of the primary targets. The energy of laser light causes rotation and resonance changes of macromolecules and the water molecules, resulting in an increased structural order of the submembraneous components in the living cells, detectable microscopically. During the photosensitization process, the red (630 nm) He-Ne laser light, during a one-photon energy activation, causes excitation of hematoporphyrin molecules to their triplet state. The excitation of HPD molecules results in a multi-step, free-radical generating effect, measured by ESR spectroscopy and studied by the ultrastructural changes of membrane organization and cell shape. Similar effects could be observed on in vitro lipid-water liposome membranes.

Animals↗