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S Horváth

Publications and source records attributed to S Horváth.

At least 19 recordsLinked to original sources
PubMed2005

Pentapeptides derived from Abeta 1-42 protect neurons from the modulatory effect of Abeta fibrils--an in vitro and in vivo electrophysiological study.

Short fragments and fragment analogues of beta-amyloid 1-42 peptide (Abeta1-42) display a protective effect against Abeta-mediated neurotoxicity. After consideration of our earlier results with in vitro bioassay of synthetic Abeta-recognition peptides and toxic fibrillar amyloids, five pentapeptides were selected as putative neuroprotective agents: Phe-Arg-His-Asp-Ser amide (Abeta4-8) and Gly-Arg-His-Asp-Ser amide (an analogue of Abeta4-8), Leu-Pro-Tyr-Phe-Asp amide (an analogue of Abeta17-21), Arg-Ile-Ile-Gly-Leu amide (an analogue of Abeta30-34), and Arg-Val-Val-Ile-Ala amide (an analogue of Abeta38-42). In vitro electrophysiological experiments on rat brain slices demonstrated that four of these peptides counteracted with the field excitatory postsynaptic potential-attenuating effect of Abeta1-42; only Arg-Val-Val-Ile-Ala amide proved inactive. In in vivo experiments using extracellular single-unit recordings combined with iontophoresis, all these pentapeptides except Arg-Val-Val-Ile-Ala amide protected neurons from the NMDA response-enhancing effect of Abeta1-42 in the hippocampal CA1 region. These results suggest that Abeta recognition sequences may serve as leads for the design of novel neuroprotective compounds.

Action Potentials↗
PubMed2003

Investigation of the effect of soil herbicides on the growth and nutrient uptake of potato.

In our experiments the effect of three preemergent herbicides was examined on potato varieties. The experiments were carried out under greenhouse conditions in pots with six Hungarian potato varieties. The following herbicides were applied: PATORAN 50 WP (metobromuron), SENCOR 70 WG (metribuzin) and COMMAND 48 EC (chlomazon). The results indicate that the variety Góliát showed the slowest growth. In the case of Lilla fresh and dry shoot weight was decreased by the application of PATORAN 50 WP and SENCOR 70 WG. Tuber weight showed a decrease with the application of SENCOR 70 WG in all varieties. The least tuber weight appeared with the varieties Kánkán and Szózszorszép. Nutrient concentration of potato and N, P and K uptake by potato were examined. In the case of White Lady, Százszorszép and Kánkán N concentration and uptake increase significantly because of SENCOR 70 WG. There was a significant increase in phosphorus concentration and uptake in White Lady, Hópehely and Kánkán varieties in all herbicide treatments. Potassium concentration increased in the case of all the six varieties because of herbicide treatments. Based on these experiments all varieties showed susceptibility against the used herbicides. The results show that important differences occur in the sensitivity and tolerance of varieties against herbicides, which are consequently significant for practical crop protection.

Herbicides↗
PubMed2001

The modulatory effect of estrogen on the neuronal activity in the barrel cortex of the rat. An electrophysiological study.

In acute experiments, the effects of iontophoretically applied 17 beta-estradiol hemisuccinate on the activity of the primary somatosensory cortical neurons were studied in ovariectomized rats by extracellular single-unit recording. 17 beta-Estradiol increased both the spontaneous and the vibrissa deflection-evoked responses, with an average latency of 24 min. It is suggested that this relatively long latency of the 17 beta-estradiol effect is based not so much on membrane mechanisms as on genomic mechanisms.

Animals↗
PubMed2001

[The use of vinpocetine in chronic disorders caused by cerebral hypoperfusion].

The clinical signs and symptoms of so-called "cerebrovascular insufficiency" or "cerebral vascular dysfunction" have the characteristics of those of chronic cerebral hypoperfusion. The clinical features of chronic cerebral hypoperfusion often show the symptoms of cognitive impairment and organic psychosyndromes. Cerebral hypoperfusion could be found in dementias of different origin (subcortical arteriosclerotic leucoencephalopathy [Binswanger], vascular dementia, Alzheimer's disease, etc.). Pathological changes caused by chronic cerebral hypoperfusion often confined only to the white matter (demyelisation, glial activation, damage of oligodendroglial cells, as well as scattered cell death). Each therapy has an influence on the biochemical and pathophysiological alterations caused by chronic cerebral hypoperfusion can be used with reason in these disorders. The mechanism of action of vinpocetine is interfering on many aspects with the biochemical and pathophysiological processes attributable to chronic cerebral hypoperfusion, independently of the original alteration responsible for hypoperfusion. This fact might give an explanation on the beneficial effect of vinpocetine on clinical signs and symptoms of chronic cerebrovascular insufficiency.

Calcium Channel Blockers↗
PubMed2001

[The pathological and clinical consequences of chronic cerebral hypoperfusion].

Comprehensive studies investigating clinical, biochemical and pathomorphological consequences of chronic cerebral hypoperfusion were carried out only in recent years. Despite of different pathological processes resulting in chronic reductions of cerebral blood flow, the pathophysiological, biochemical and pathomorphological alterations and the clinical consequences are causing or modifying the pathological and clinical pictures in a similar manner. Cerebral hypoperfusion is verifiable in patients with ischaemic strokes, in diseases characterised by mild or serious cognitive impairment and in dementias of vascular or of degenerative origins, even it can be shown in normal ageing. This review gives a summary of pathophysiological, pathomorphological and clinical consequences of chronic cerebral hypoperfusion, and the role of that in evolution and persistence of cognitive disturbances.

Animals↗
PubMed2001

Tissue-specific signal(s) activate the promoter of a metallocarboxypeptidase inhibitor gene family in potato tuber and berry.

The molecular basis of the differential expression of the GM7-type metallocarboxypeptidase inhibitor (MCPI) genes in tuberizing (StMCPI) and non-tuberizing Solanum species (SbMCPI) was investigated. It was shown that the StMCPI is encoded by a gene family in Solanum tuberosum (potato), but SbMCPI might be a single-copy gene in the non-tuberizing species Solanum brevidens. The StMCPI promoter shows evolutionary relatedness to the S. brevidens-derived SbMCPI and to the fruit-specific tomato promoter 2A11. Both StMCPI and SbMCPI promoter regions were able to confer tuber- and berry-specific expression for the beta-glucuronidase reporter gene in potato suggesting that the difference in MCPI gene expression is in trans regulatory factors between the tuberizing and the non-tuberizing Solanum species. The MCPI promoters did not respond to metabolic, environmental or hormonal signals in leaves. Thus, the MCPI genes are regulated in a different way than the other known tuber-specific genes and potentially are suitable for biotechnological application in potato to provide specific transgene expression in tuber and berry.

Amino Acid Sequence↗
PubMed1999

Estrogen effects on arcuate neurons in rat. An in situ electrophysiological study.

In acute experiments, the effects of i.p. 17beta-estradiol on the activity of arcuate neurons were studied in ovariectomized rats. 17Beta-estradiol (100 microg/100g, i.p.) increased the spontaneous activity of the observed arcuate neurons with a latency of 20-25 min. In some neurons spontaneous activity could be influenced by stimulation of the olfactory and somatosensory systems. Activation of the trigeminal system significantly increased the spontaneous activity of the studied units, while stimulation of the accessory olfactory bulb decreased it, both with and without 17beta-estradiol treatment. It is suggested that the 20-25 min latency of the 17beta-estradiol effect is based not so much on membrane as on genomic mechanisms. This suggestion is supported by immunocytochemical studies: 17beta-estradiol treatment significantly decreased the number of GABA-positive axo-somatic synapses in the arcuate nucleus.

Animals↗
PubMed1998

A modified method of intracytoplasmic sperm injection without the use of polyvinylpyrrolidone.

In a controlled study we compared the outcome of intracytoplasmic sperm injection (ICSI) performed by two different methods. The oocytes from 20 patients were equally divided into two groups and injected either by conventional ICSI using polyvinylpyrrolidone (PVP) or by a modified PVP-free ICSI procedure. While in the conventional ICSI method the spermatozoon is aspirated into the injection pipette, in the modified ICSI procedure the spermatozoon is attached to the end of the narrow micropipette by aspirating its tail. The sperm head is never drawn into the pipette. Accordingly, even a fast-moving spermatozoon can be 'caught' easily. As a result of such an aspiration the spermatozoon loses its motility. Therefore, PVP is required neither to slow down the movement of the spermatozoon nor to facilitate the movement of the solution in the injection pipette. A total of 230 mature oocytes were injected by both methods and the results were analysed. No differences were observed in survival rate between the two ICSI procedures (89% and 91%, respectively). However, the proportion of normally fertilized oocytes was significantly higher after microfertilization by modified ICSI (74%) when compared with the outcome of the conventional ICSI method (62%). The frequency of abnormal fertilization was not influenced by the method of ICSI used. The cleavage rate and quality of resulting embryos were also comparable. In conclusion, we have demonstrated a modified ICSI method which does not require the use of PVP. When compared with the conventional ICSI procedure, even better fertilization rates can be achieved. The proposed ICSI modification may provide an alternative procedure for elimination of the potentially harmful effects which may be associated with conventional ICSI.

Cleavage Stage, Ovum↗
PubMed1996

Detectable serum IgE levels in Graves' ophthalmopathy.

Graves' ophthalmopathy is an organ-specific autoimmune disorder in which the target organs are infiltrated by T lymphocytes and polymorphonuclear neutrophils that release immunoregulatory cytokines in the thyroid and retrobulbar tissues. Th2-type cytokines (IL-4, IL-5, IL-6) support the inflammatory symptoms and immunoglobulin production, e.g. IgE isotype. IgE is thought to play a part not only in allergy but also in the normal immune responses, antigen processing and presentation. Since studies report IgE accumulation around the extraocular muscles in ophthalmopathy and a correlation between the total IgE levels and the severity of ophthalmopathy in Graves' disease, we measured the total IgE levels in 56 patients with Graves' disease (associated with ophthalmopathy in 47 patients) and in 42 healthy subjects as controls to determine if IgE plays a part in the autoimmune or the local inflammatory processes. For detection we used the Enzymun-Test IgE, which was a two-step ELISA sandwich assay. Elevated circulating IgE levels could be demonstrated in non-treated hyperthyroid Graves' patients in comparison with the controls (51.02 +/- 113.16 IU/ml vs 34.95 +/- 54.91 IU/ml, P < 0.01). The IgE levels were higher in patients with active inflammatory eye signs (63.65 +/- 130.41 IU/ml) than in controls (P < 0.007). The anti-thyroid drug and glucocorticoid management decreased the total IgE levels, and the difference was significant after the treatment compared with the values at the beginning of the therapy in the Graves' patients without ophthalmopathy (17.34 +/- 6.34 IU/ml vs 13.01 +/- 9.86 IU/ml, P < 0.03). In conclusion, since the results suggested that IgE plays a role in the inflammatory eye signs in Graves' ophthalmopathy, we propose administering antihistamines for medical management.

Adult↗
PubMed1994

Galanin immunoreactive neurons in the medulla oblongata of rats.

The distribution of galanin-immunoreactive (-ir) neurons in the medulla oblongata was mapped with light microscopic immunohistochemistry. No immunopositive perikarya were seen in untreated rats. Two days after colchicine treatment, galanin immuno-positive neurons were localized in the following areas: 1) raphe nuclei (magnus, pallidus and obscurus); 2) in various parts of the reticular formation, mainly in the territory of the catecholaminergic groups and in the peritrigeminal subdivision of the lateral reticular nucleus; 3) vagal nuclei (nucleus of the solitary tract, nucleus ambiguous); 4) two cell groups at the ventral surface of the rostro-caudal middle portion of the medulla oblongata (they do not correspond to any known demarkated anatomical nuclei, but related to the chemosensitive medullary area); 5) in the gelatinous part of the spinal trigeminal nucleus. The wide distribution of galanin neurons in the medulla support data that had been reported on the role of this peptide in various viscerosensory and autonomic mechanisms. In addition to these, galanin seems to be an important factor in the restoration of lesioned neurons (nerve growth factor-like activity). An increased galanin mRNA expression can be seen in dorsal vagal or hypoglossal motor neurons after intracranial transections of vagal or hypoglossal nerves, respectively. Transections of the olivocerebellar tract induced galanin gene expression in neurons of the contralateral inferior olive. After brainstem hemisection, galanin immunopositivity was seen in cells of the nucleus of the solitary tract due to the transection of ascending projections of this primary autonomic center in the medulla oblongata.

Animals↗
PubMed1992

Vascular ontogeny of the septal region in rats.

The development of the arterial and venous systems of the septum was studied in rat brains injected daily with India ink, from the 11th embryonic (E) until the first postnatal day. Arterial blood is supplied to the septum by the unpaired hemispheric artery, the stem and septal branches of which are to be recognized on the 14th and 15th embryonic days respectively. At earlier stages, e.g. on E12, a capillary network, the hemispheric plexus, can be seen between the two hemispheres contributing to the blood supply of the septum during the early phase (E14 to E18) of development. From E18 onwards, the arterial supply of the septum is derived only from direct branches of the hemispheric artery; one group of them being dorsal (infracallosal) and the other ventral (subcallosal). The venous drainage of the septum is bidirectional: 1) Veins of the ventral group leading to the interperioptic sinus are seen on E14. At first they collect blood only from a small rostral portion of the septum, but later their territory expands to include the anteroventral two-thirds of the septum. 2) The dorsal septal veins drain into the great cerebral vein (of Galen), or into the superior sagittal sinus directly. Initially, twigs run directly into the great cerebral vein. These later become the tributaries of the internal cerebral vein, which appears on E17 or E18. Until E18 this dorsally-directed drainage predominates, whereas at birth it becomes restricted to one third of the septum as a result of a gradual regression. The development of both arterial and venous circulations of the septum is complete at birth.

Animals↗
PubMed1992

[Cystic lesions of the prostate--diagnosis, therapy and clinical significance].

The authors present an account of results of examinations in 162 patients with cancer of the prostate, benign hyperplasia of the prostate, inflammatory diseases of the prostate and patients with a normal finding on palpation of the prostate. The patients were subjected to clinical, laboratory, histopathological and transrectal ultrasonography of the prostate. In one patient a CT examination of the prostate was made. In the group were seven patients with cystic prostate lesions (4.3%). In the group of patients with inflammatory diseases of the prostate they observed cystic changes in five patients (14.2%). The most important group was formed by two patients with abscesses of the prostate and one patient with an ascended utriculus prostaticus. Transrectal ultrasonography of the prostate was the supreme method for the diagnosis of cystic prostate lesions.

Adolescent↗
PubMed1991

The origin of somatostatin-containing nerve fibers innervating the hypothalamic supraoptic nucleus.

Light and electron microscopic studies were performed to study the connections between somatostatin (SOS)-containing nerve terminals and vasopressin (VP)-containing neurons in the rat supraoptic nucleus (SON). SOS-positive fibers innervate the SON in both the oxytocinergic and vasopressinergic areas. Using double immunostaining symmetric synaptic contacts were visualized between SOS immunoreactive boutons and the soma of VP immunopositive neurons. Surgical transection deafferentiating the SON from all possible directions do not effect the presence of SOS immunopositive fibers. These results suggest a local origin of the SOS fibers. Somatostatin-containing perikarya can indeed be found at the dorsal border of the SON at the rostral and caudal pole of the nucleus--we suggest that these cells innervate the SON. The presence of synaptic contacts between SOS fibers and VP neurons as well as the lack of these fibers in the VP deficient Brattleboro rats indicate a role for SOS in the synthesis and/or release of vasopressin in the SON.

Animals↗
PubMed1990

The influences of hyperosmolality and synaptic inputs on galanin and vasopressin expression in the hypothalamus.

Galanin is a neuropeptide that is widely distributed throughout the rat central nervous system. It is co-localized with vasopressin in magnocellular neurons of the hypothalamic paraventricular and supraoptic nuclei. Vasopressin biosynthesis is increased there by various hyperosmolar stimuli, including drinking 2% saline. We previously demonstrated that the chronically hyperosmolar Brattleboro rat has increased biosynthesis of galanin in the paraventricular and supraoptic nuclei. In this report we show using hybridization histochemistry that drinking 2% saline also increased galanin transcripts in these nuclei. We also demonstrate using hybridization histochemistry and immunohistochemistry that knife cuts that sever hypothalamo-hypophysial fibers transiently elevated galanin expression in the supraoptic nucleus ipsilateral to the lesion and depressed vasopressin expression ipsilaterally. Pituitary stalk transections also elevated galanin and decreased vasopressin transcripts. In addition, various knife cuts in the caudal hypothalamus were able to dissociate the expression of vasopressin and galanin, although co-localized and similarly affected by hyperosmolality in the supraoptic nucleus. Unilateral sagittal knife cuts that divided the posterior hypothalamus but avoided the hypothalamo-hypophysial pathway, as well as hemisections at the level of the premammillary area, resulted in ipsilateral elevations of galanin transcripts without significantly affecting vasopressin expression. These results indicate that independent intracellular signal transduction pathways exist for regulating expression of the two genes.

Animals↗
PubMed1990

Predicting neuroleptic response from a combination of multilevel variables in acute schizophrenic patients.

A predetermined set of 22 sociodemographic, psychosocial, clinical, neurocognitive and biochemical potential predictor variables was tested in 98 schizophrenic patients admitted for relapse. The patients were treated with neuroleptics, mostly with haloperidol, for 28 d. Ten of the 22 variables correlated significantly with the neuroleptic response. Using stepwise multiple regression analyses, an optimal combination of 5 predictors was found to be in hierarchical order: disturbances of premorbid adjustment, intensity of positive symptoms at admission, family history of schizophrenia, working ability during the year before admission and serum dopamine-beta-hydroxylase. The 5 best predictors explained 29% of outcome variance, and all 22 variables together explained 35%. Such neurological characteristics as neurological soft signs, handedness, abnormal voluntary movements, spontaneous blink rate and cognitive impairment did not predict the treatment response. Several psychopathological, psychosocial and clinical predictors known from the literature could also be confirmed by cross-validation.

Activities of Daily Living↗
PubMed1989

[Direct revascularization of the myocardium using the internal mammary artery].

The best graft in coronary bypass operations is the internal mammary artery (IMA) as its rate of staying open for long term is better than that of the vena saphena magna. The authors present the operative and postoperative results of their first 161 patients who were subjected to IMA grafting. 126 were men and 35 women of the patients and the average age was 50.2 years. Before the operation the majority of the patients belonged to NYHA III state (69.6%). 86 patients (53.4%) had myocardial infarction before the operation, 50.3% were operated on because of 3 blood vessel diseases and the stricture of the main trunk was confirmed in 12.4%. 128 patients underwent only coronary bypass operation, in the others thrombendarterectomy (17 patients), valvular operation (11 patients) and resection of the left ventricular aneurysma (5) were carried out simultaneously. The IMA graft was placed in the majority of the cases on the LAD (70.8%) or as a sequential anastomosis on the LAD-diagonal system (21.1%). The average number of peripheral anastomoses was 2.8 anastomoses patient. 2.5% was the rate of early mortality (4 patients), reoperation was performed in 10 cases because of bleeding or tamponade and perioperative infarction occurred in 8 cases. 3.1% was the rate of late mortality (5 patients). The average follow-up examination time was 12.7 months (3-39 months). At the postoperative examinations 88.8% of the patients were free of angina and 108 patients got into NYHA I state after the operation. Of the 43 control bicycle ergometric examinations 35 were negative and 8 positive.(ABSTRACT TRUNCATED AT 250 WORDS)

Female↗
PubMed1989

Electron microscopic immunocytochemical evidence for the existence of bidirectional synaptic connections between growth hormone-releasing hormone- and somatostatin-containing neurons in the hypothalamus of the rat.

Synaptic contacts between growth hormone-releasing hormone (GHRH)- and somatostatin-containing neurons were demonstrated in the rat hypothalamus by a double-staining immunocytochemical method at the electron microscopic level. Somatostatin-immunoreactive nerve terminals synapse on GHRH-positive dendrites and cell bodies in the arcuate nucleus. A fine network of GHRH-immunopositive nerve terminals was observed at the light microscopic level in the rostral part of the periventricular nucleus and in the dorsal part of the arcuate nucleus around somatostatin-containing neuronal elements. With the electron microscope synaptic contact between GHRH-containing nerve terminals and somatostatin-containing dendrites are demonstrated. The reciprocal innervation between GHRH- and somatostatin-containing neurons that project to the median eminence and regulate growth hormone secretion must allow them to coordinate their activities.

Animals↗