Biomedical subjects

I Kovács

Publications and source records attributed to I Kovács.

At least 19 recordsLinked to original sources

PubMed2006

Melanoma cells exhibit strong intracellular TASK-3-specific immunopositivity in both tissue sections and cell culture.

Amplification of the kcnk9 gene and overexpression of the encoded channel protein (TASK-3) seems to be involved in carcinogenesis. In the present work, TASK-3 expression of melanoma cells has been studied. For the investigation of TASK-3-specific immunolabelling, a monoclonal antibody has been developed and applied along with two, commercially available polyclonal antibodies targeting different epitopes of the channel protein. Both primary and metastatic melanoma cells proved to be TASK-3 positive, showing prominent intracellular TASK-3-specific labelling; mostly concentrating around or in the proximity of the nuclei. The immunoreaction was associated with the nuclear envelope, and with the processes of the cells and it was also present in the cell surface membrane. Specificity of the immunolabelling was confirmed by Western blot and transfection experiments. As TASK-3 immunopositivity of benign melanocytes could also be demonstrated, the presence or absence of TASK-3 channels cannot differentiate between malignant and non-malignant melanocytic tumours.

Animals↗

PubMed2004

Evaluation of the lung function test in reversible glottis-dilating operations.

Our aim was to obtain an objective evaluation of the airway before and after reversible glottis-dilating operations using the lung function test. Bilateral abductor vocal cord paralysis remains mostly a complication of thyroid surgery. After thyroid surgery, the paralysis is potentially reversible, and the patient has a chance for recovery mostly in the first 6 months. According to these considerations, a reversible vocal cord laterofixation procedure was used instead of tracheostomy. The operations were performed endoscopically using high-frequency JET ventilation and the special endo-extralaryngeal suture technique by Lichtenberger. This technique was used in 92 cases. The pre- and postoperative data of reversible glottis-dilating techniques could be compared in 23 non-selected patients. Lung function tests that were performed were forced inspiratory volume (FIV1), forced expiratory volume (FEV1), peak inspiratory flow rate (PIF), peak expiratory flow rate (PEF) and resistance of the airways (Raw). For the evaluation of the functional results, we used the body-pletysmograph. Our aim was to obtain a quantitative evaluation of the results. These values allow us to compare the results achieved by using different glottis-dilating methods. The FEV1 (forced expiratory volume) improved 25%, and the FIV1 (forced inspiratory volume) improved 39% after the operations on average. PEF (peak expiratory flow rate) and PIF (peak inspiratory flow rate) improved 37 and 45% after glottis-dilating surgery on average. The Raw (resistence of airways) was 271.5% on average before the operations, and after reversible glottis-dilating operations decreased to a level of 200.6%.

Adolescent↗

PubMed2004

Serum carotenoid and retinol levels during childhood infections.

BACKGROUND: In recent years, new physiological functions of vitamin A have been identified, including its role in immune defense. The antioxidant potential of carotenoids is thought to account for their health benefits. The aim of this study was to investigate the concentration changes in the provitamin-A (alpha- and-beta-carotene, beta-cryptoxanthin) and of the non-provitamin-A carotenoids (lutein, zeaxanthin and lycopene) in children with acute infections. METHODS: Serum retinol and carotenoid concentrations were measured by HPLC in 45 children suffering from acute infections and in 29 healthy controls. In addition 15 healthy children collected food samples over 2 days. C-reactive protein (CRP) levels were measured by turbidimetry. RESULTS: Serum levels of beta-carotene, alpha-carotene, beta-cryptoxanthin and retinol and non-provitamin-A carotenoid lutein and zeaxanthin concentrations were significantly lower in children with infections compared to healthy controls. There were significant negative correlations between CRP levels and serum beta-carotene and retinol concentrations. The average intake of retinol equivalents was 1.1 +/- 0.6 mg/day. CONCLUSION: Serum retinol and provitamin-A as well as non-provitamin-A carotenoid concentrations were lower in children with acute phase infections compared to healthy controls. The inverse correlations between CRP and beta-carotene or retinol indicate either decreased synthesis or increased utilization of these antioxidants.

Adolescent↗

PubMed2004

Opposite roles of protein kinase C isoforms in proliferation, differentiation, apoptosis, and tumorigenicity of human HaCaT keratinocytes.

We have previously shown that the protein kinase C (PKC) system plays a pivotal role in regulation of proliferation and differentiation of the human keratinocyte line HaCaT which is often used to assess processes of immortalization, transformation, and tumorigenesis in human skin. In this paper, using pharmacological and molecular biology approaches, we investigated the isoform-specific roles of certain PKC isoenzymes (conventional cPKCalpha and beta; novel nPKCdelta and epsilon) in the regulation of various keratinocyte functions. cPKCalpha and nPKCdelta stimulated cellular differentiation and increased susceptibility of cells to actions of inducers of apoptosis, and they markedly inhibited cellular proliferation and tumor growth in immunodeficient mice. In marked contrast, cPKCbeta and nPKCepsilon increased both in vitro and in vivo growth of cells and inhibited differentiation and apoptosis. Our data present clear evidence for the specific, antagonistic roles of certain cPKC and nPKC isoforms in regulating the above processes in human HaCaT keratinocytes.

Animals↗

PubMed2004

Differential distribution of TASK-1, TASK-2 and TASK-3 immunoreactivities in the rat and human cerebellum.

In this work, the distributions of some acid-sensitive two-pore-domain K+ channels (TASK-1, TASK-2 and TASK-3) were investigated in the rat and human cerebellum. Astrocytes situated in rat cerebellar tissue sections were positive for TASK-2 channels. Purkinje cells were strongly stained and granule cells and astrocytes were moderately positive for TASK-3. Astrocytes isolated from the hippocampus, cerebellum and cochlear nucleus expressed TASK channels in a primary tissue culture. Our results suggest that TASK channel expression may be significant in the endoplasmic reticulum of the astrocytes. The human cerebellum showed weak TASK-2 immunolabelling. The pia mater, astrocytes, Purkinje and granule cells demonstrated strong TASK-1 and TASK-3 positivities. The TASK-3 labelling was stronger in general, but it was particularly intense in the Purkinje cells and pia mater.

Animals↗

PubMed2004

Abnormal cell-specific expressions of certain protein kinase C isoenzymes in peripheral mononuclear cells of patients with systemic lupus erythematosus: effect of corticosteroid application.

We have studied the expressions of various protein kinase C (PKC) isoenzymes in T cells and monocytes from patients with systemic lupus erythematosus (SLE), in comparison to those of healthy controls and patients with other immunological disorders. As measured by Western blotting, the levels of PKCbeta, delta, eta, epsilon, theta and zeta (but not of PKCalpha) significantly decreased in T cells of SLE patients. In monocytes, however, we observed marked suppressions only in the expressions of PKCdelta, epsilon and zeta but not in the expressions of other PKC isoforms. In vivo corticosteroid application, as well as in vitro steroid treatment of monocytes, elevated the expressions of most isoforms close to normal values; however, the decreased levels of PKCtheta and zeta were not affected by steroid application. These alterations were characteristic to SLE because we could not detect any changes in the PKC levels in mononuclear cells of primary Sjögren's syndrome and mixed connective tissue disease patients. These results suggest that impaired PKC isoenzyme pattern may exist in the T cells and monocytes of SLE patients. Furthermore, the clinically efficient glucocorticoid application in SLE can increase the expression of some members of PKC system.

Adrenal Cortex Hormones↗

PubMed2003

HCN channels contribute to the intrinsic activity of cochlear pyramidal cells.

A hyperpolarization-activated current recorded from the pyramidal cells of the dorsal cochlear nucleus was investigated in the present study by using 150- to 200-microm-thick brain slices prepared from 6- to 14-day-old Wistar rats. The pyramidal neurones exhibited a slowly activating inward current on hyperpolarization. The reversal potential of this component was -32 +/- 3 mV (mean +/- SE, n = 6), while its half-activation voltage was -99 +/- 1 mV with a slope factor of 10.9 +/- 0.4 mV (n = 27). This current was highly sensitive to the extracellular application of both 1 mM Cs+ and 10 microM ZD7288. The electrophysiological properties and the pharmacological sensitivity of this current indicated that it corresponded to a hyperpolarization-activated non-specific cationic current (Ih). Our experiments showed that there was a correlation between the availability of the h-current and the spontaneous activity of the pyramidal cells, suggesting that this conductance acts as a pacemaker current in these neurones. Immunocytochemical experiments were also conducted on freshly isolated pyramidal cells to demonstrate the possible subunit composition of the channels responsible for the genesis of the pyramidal h-current. These investigations indicated the presence of HCN1, HCN2 and HCN4 subunits in the pyramidal cells.

Animals↗

PubMed2001

[Effect of ciprofibrate on the endothelial dysfunction of patients with combined dyslipidemia].

Endothelial dysfunction can be detected in the early phase of atherosclerosis. Two unresolved questions have been raised the wether, (1) the dyslipidemic state alone without any other risk factors can be harmful for the endothelial function measured by ultrasound, and (2) the use of the antilipidemic fibrate is sufficient to influence the endothelial functions. From 38 subjects with solitary combined dyslipidaemia 32 (84%) showed endothelial dysfunction measured by flow mediated vasodilatation (FMD) on the forearm and this group of patients was featured only by higher fibrinogen levels (no differences on BMI, serum lipid and glucose level). The patients with endothelial dysfunction were treated with 100 mg of ciprofibrate per day (12 women, 20 men, average age: 44.6 +/- 9 years, BMI 24.6 +/- 3.4 kg/m2). The pretreatment serum lipid levels were: total cholesterol 6.9 +/- 0.4, triglyceride 4.2 +/- 0.3, HDL cholesterol 1.13 +/- 0.21 mmol/l. After the 4 weeks treatment period the cholesterol and triglyceride level decreased, the concentration of HDL cholesterol increased significantly, which changes were in correspondence with significant improvement of FMD (3.9 +/- 0.7% vs. 7.0 +/- 1.6%). The level of fibrinogen also declined significantly. At the 8th week there were no significant further changes compared to the data received at the 4th week. Using the lineal regressive analysis the improved vasodilatator respond at both check points was correlated only with the fall of total cholesterol level. The ciprofibrate was suspended after the 8th week for a 4 weeks period and the triglyceride and the fibrinogen levels increased whereas the HDL cholesterol level decreased significantly. The FMD impaired significantly (to 5.8 +/- 1.2%). There were no correlations among the changes. The results demonstrated the lipid and probably non-lipid-factors are important in these early damages of endothelial functions.

Adult↗

PubMed2001

Quinazolone-alkyl-carboxylic acid derivatives inhibit transmembrane Ca(2+) ion flux to (+)-(S)-alpha-amino-3-hydroxy-5-methylisoxazole-4-propionic acid.

Comparison of the kinetics of the inward Ca(2+) ion flux to (S)-alpha-Amino-3-hydroxy-5-methylisoxazole-4-propionic acid [(S)-AMPA] in cerebrocortical homogenates and that of the previously reported transmembrane Na(+) ion influx mediated by an AMPA receptor in hippocampal homogenates established that the agonist-induced opening of the AMPA receptor channels occurs in two kinetically distinguishable phases. Here we report that the 2-methyl-4-oxo-3H-quinazoline-3-acetic acid (Q1) inhibits the major slow-phase response specifically, whereas the acetyl piperidine derivative (Q5) is a more potent inhibitor of the fast-phase response. Both the quinazolone-3-propionic acid (Q2) and the quinazolone-3-acetic acid methyl ester (Q3) enhanced the slow-phase response to (S)-AMPA. The information provided by docking different Q1, Q2, and Q5 models at the ligand-binding core of iGluRs were used to define agonistic and antagonistic modes of interactions. Based on the effects of quinazolone-3-alkyl-carboxylic acid derivatives on specific [(3)H]Glu binding and kinetically distinguishable Ca(2+) ion permeability responses to (S)-AMPA and molecular modeling, the fast- and the slow-phase (S)-AMPA-elicited Ca(2+) ion fluxes were corresponded to different subunit compositions and degrees of S1S2 bridging interaction relative to substitution of kainate thereupon. Substitutions of agonists and antagonists into the iGluR2 S1S2 ligand binding core induced different modes of domain-domain bridging.

Acetates↗

PubMed2001

Glucocorticosteroid dependent decrease in the activity of calcineurin in the peripheral blood mononuclear cells of patients with systemic lupus erythematosus.

OBJECTIVE: To compare the activity of calcineurin in the peripheral blood mononuclear cells (PBMC) of 32 patients with systemic lupus erythematosus (SLE) and 35 healthy controls. METHODS: The activity of calcineurin was assayed in the supernatants of sonicated mononuclear cells. RESULTS: There was no significant difference in the calcineurin activity of patients with SLE not taking glucocorticosteroids (GCS) compared with the healthy controls. On the other hand, the activity of calcineurin was reduced in patients with SLE taking GCS, correlating negatively with the dose of GCS. The stimulation of PBMC by phorbol ester and calcium ionophore decreased the calcineurin activity both in patients with SLE and in healthy controls. GCS could also reduce calcineurin activity in the mononuclear cells of healthy subjects in vitro. CONCLUSIONS: In patients with SLE the decrease in the calcineurin activity of PBMC depended on the dose of GCS used for treatment, and it was not a disease specific alteration. The higher the dose of GCS, the greater the inhibition of calcineurin activity. The reduction of calcineurin activity is a new element in the immunosuppressive effects of GCS during the treatment of patients with SLE.

Adolescent↗

PubMed2001

Contour integration deficits in anisometropic amblyopia.

PURPOSE: Previous retrospective studies have found that integration of orientation information along contours defined by Gabor patches is abnormal in strabismic, but not in anisometropic, amblyopia. This study was conducted to reexamine the question of whether anisometropic amblyopes have contour integration deficits prospectively in an untreated sample, to isolate the effects of the disease from the effects of prior treatment-factors that may have confounded the results in previous retrospective studies. METHODS: Contour detection thresholds, optotype acuity, and stereoacuity were measured in a group of 19 newly diagnosed anisometropic amblyopes before initiation of occlusion therapy. Contour detection thresholds were measured using a card-based procedure. RESULTS: Significant interocular differences in contour detection thresholds were present in 14 of the 19 patients with anisometropic amblyopia. CONCLUSIONS: Contour integration deficits are a common, but not universal, finding in untreated anisometropic amblyopia. Differences in the prevalence of contour integration deficits between the present study and that of another study may lie in differences in treatment history and/or in the sensitivity of the two different contour integration tasks.

Adolescent↗

PubMed2001

[The role of percutaneous radiologic interventions in the treatment of pancreatic pseudocysts].

Authors evaluate the indications and results of percutaneous puncture and drainage of pancreatic pseudocysts. The interventions were performed in 20 patients. The first line treatment is usually surgical. Percutaneous drainage or aspiration is suggested if the patient is symptomatic, the size of pseudocyst is between 3 and 6 cms and when it can be punctured using radiological procedures, without the risk of damaging other organs. Previous peripancreatic operation, high-risk surgical intervention and the refusal of the operation by the patient should also be considered. Percutaneous drainage is an alternative method for the treatment of pancreatic pseudocysts. The advantages of this procedure are: It is minimally invasive, complications are rare and reintervention is possible. Disadvantage is high risk of recurrence.

Adult↗

PubMed2001

Decreased arachidonic acid release in peripheral blood monocytes of patients with systemic lupus erythematosus.

OBJECTIVE: To investigate the release of arachidonic acid (AA) in unfractionated peripheral blood mononuclear cells (PBMC), separated monocytes and T lymphocytes of patients with systemic lupus erythematosus (SLE). METHODS: AA release was measured in cells from 56 patients with SLE and from 48 controls. Of the 56 patients with SLE, 38 were receiving glucocorticosteroids and 18 were not. [3H]AA was incorporated into the membranes of PBMC and purified subsets of monocytes and T lymphocytes. The release of [3H]AA was measured both in nonstimulated cells cultured for 24 h and in cell cultures stimulated by phorbol ester (PMA) and Ca2+ ionophore for 4 h. RESULTS: In the PBMC of SLE patients not taking glucocorticosteroids, the release of AA was decreased in both stimulated and nonstimulated cells. There was a decrease of AA production in monocytes but not in T lymphocytes. This phenomenon could be observed in the active and inactive phases of the disease. CONCLUSION: A defect in AA production may exist in the peripheral monocytes of patients with SLE, resulting in decreased release of AA in patients not receiving glucocorticosteroid therapy.

Adolescent↗

PubMed2000

Differences in the changes of allergen-specific IgE serum levels and the chemiluminescence of peripheral blood phagocytes in patients with allergic rhinoconjunctivitis during the ragweed season.

The objective of this study was to compare the changes in the values of allergen-specific serum IgE levels and zymosan-induced whole blood chemiluminescence (CL) in 41 patients who had exclusively only ragweed allergy in the season of acute symptoms of disease in July, August and September. All patients had allergic rhinitis or rhinoconjunctivitis. Each patient was investigated as a self-control. The ragweed-specific IgE levels were measured by enzyme immunoassay (EIA). The luminol amplified zymosan-induced CL of whole human blood was detected. The allergen-specific serum IgE levels showed slight, but not significant, gradually increasing elevations during the whole season. On the other hand, significant increases were found in the values of the basal but especially in the zymosan-stimulated CL of peripheral blood phagocytes during the acute phase of allergy. Both the basal and the zymosan-induced CL reflected significantly the activated state of the immune system. These observations clearly show that there are well detectable signs of the systemic activation of the immune system in allergic rhinoconjunctivitis beside the local alterations. In addition, the measurements of the basal and zymosan-induced CL of peripheral phagocytes could clearly reflect the clinical state of disease in vitro.

Adult↗

PubMed2000

Nuclear localization of a hypoxia-inducible novel non-symbiotic hemoglobin in cultured alfalfa cells.

We have isolated a 483-bp-long full-length cDNA clone encoding a non-symbiotic hemoglobin called Mhb1, the first one found in alfalfa. This non-symbiotic hemoglobin is a single copy gene localized in linkage group 4 in diploid Medicago genome. The Mhb1 mRNA was found only in the roots of alfalfa plants. The Mhb1 gene was inducible by hypoxia and showed no induction by cold stress treatment. The Mhb1 transcript level increased at the G2/M boundary in a synchronized alfalfa cell suspension culture. The majority of Mhb1 protein was shown to be localized in the nucleus and smaller amounts were detected in the cytoplasm. A potential link to the nitric oxide signalling pathway is also discussed.

Amino Acid Sequence↗

PubMed2000

Perceptual organization, the disorganization syndrome, and context processing in chronic schizophrenia.

Schizophrenia patients' perceptual organization abilities were assessed with a psychophysically well-controlled measure of contour integration. Compared with psychiatric and staff controls, schizophrenia patients were less able to detect contours comprising Gabor elements as the detection of these contours relied increasingly on long-range spatial interactions. Impaired task performance was also found to correlate significantly with higher levels of disorganized symptomatology. These data provide further evidence for impaired perceptual grouping in schizophrenia. In addition, the findings support the hypothesis that a common cortical processing algorithm involving contextual coordination is impaired in schizophrenia, leading to reduced binding of object features in vision, and reduced contextual disambiguation of linguistic information during thought and speech.

Adult↗

PubMed2000

[Changes of authorship characteristics in Hungarian medical publications in the period of 1967-97].

Authorship characteristics of publications appeared in the 1967-1977-1987-1997 volumes of the Orvosi Hetilap (Medical Weekly) were analysed and compared with corresponding data in the international medical literature. Following results were achieved: 1. The total number of medical publications gradually decreased although the number of pages of the volumes steadily increased during the period studied; this could be explained rather by a changed structure or editorial policy than by lowering of the readiness for publishing. 2. The number of authors per paper gradually increased over a period of forty years, the same trend was observed in the world literature as well. 3. Heads of department are more and more included among the authors; previously they gave preference to the first place, presently they figure mostly as last authors. 4. As to the origin of the communications the pattern did nor change essentially: about half of the papers came from university departments, while about 20 to 30 per cent of the authors worked in hospitals; the remaining papers were the result of cooperations. 5. Both the absolute number of ratio of the dual publication of "original" articles decreased in the last twenty years; the language used for dual publication in international journals markedly changed: while in 1967 both English and German were used with the same frequency, in 1997 English was chosen in 95 per cent of dual publications.--Results were discussed rather shortly, similar studies in the international literature were cited, but authors did not intend neither to outline their's point of view nor to to take part in the current international discussion on authorship.

Authorship↗

PubMed2000

Deramciclane inhibits N-methyl-D-aspartate receptor function.

Effects of the novel anxiolytic drug deramciclane on excitatory amino acid release and transmembrane Ca(2+) ion flux processes were compared in rat cerebrocortical homogenates containing resealed plasmalemma fragments and nerve endings. Deramciclane (10 microM) significantly inhibited [(3)H]D-aspartate release and transmembrane Ca(2+) flux to N-methyl-D-aspartate in the absence of Mg(2+). By contrast, inhibition of [(3)H]D-aspartate release and transmembrane Ca(2+) flux evoked by 0.1 mM (S)-alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionate in the presence of Mg(2+) and 10 microM cyclothiazide by 10 microM deramciclane was not significant. In the presence of N-methyl-D-aspartate receptor antagonists, deramciclane (10 microM) did not inhibit [(3)H]D-aspartate release to N-methyl-D-aspartate. These results suggest an involvement of the inhibition of a presynaptic N-methyl-D-aspartate receptor in the anxiolytic properties of deramciclane.

4-Aminopyridine↗