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G Horváth

Publications and source records attributed to G Horváth.

At least 19 recordsLinked to original sources
PubMed2000

[Investigation of the cerebral projection of the vestibular system using positron emission tomography].

The authors investigated the cerebral projection of the vestibular system, using positron emission tomography, in right-handed subjects. Both sided cold caloric stimulation was used in every volunteer (n = 6). A detailed map of activated and deactivated brain regions is included. This portrays changes caused by vestibular stimulation. The contralaterally activated regions according to the stimulation side were: postcentral gyrus, transvers temporal gyrus, superior temporal gyrus, posterior part of the insula, claustrum, putamen, inferior parietal lobule, precentral gyrus, premotor cortex, cingulate gyrus. The ipsilaterally activated regions were: transvers temporal gyrus, superior temporal gyrus, inferior parietal lobule, posterior part of the insula. There was no hemispherial dominance. The activated regions partially correspond with previous results in the literature. It would like to be pointed out the Brodmann 6 region as the cortical manifestation of involuntary isometric tightening of muscles. The contralaterally deactivated regions were: inferior, superior and medius temporal gyrus, medial and medius frontal gyrus, inferior occipital gyrus, parahippocampal gyrus and hippocampus. Ipsilaterally deactivated regions were: superior and medial frontal gyrus, inferior temporal gyrus, angular gyrus, parahippocampal gyrus and hippocampus, fusiform and inferior occipital gyrus. There was prominent hemispherial dominance in the stimulated, ipsilateral side. The deactivation based functional connection between the hippocampus and the vestibular system was pointed out in such a relation for the first time in this report.

Adult↗
PubMed2000

[MR-guided diagnostic and therapeutic interventions. Review and own preliminary experience].

Magnetic resonance (MR) guided diagnostic and therapeutic interventions are relatively new methods in the larger field of radiologic interventions. Good spatial resolution and soft tissue characterisation, multiplanar imaging capability, functional imaging and up-to-date computer systems enable MR imaging to guide a wide range of interventional procedures. Biopsies, punctures and drainages of fluid collections, tumor ablations and vascular interventions can be performed with the help of MRI. MR imaging provides an unique opportunity for planning, guiding and monitoring certain types of intraoperative procedures. The authors outline the basic features of MR intervention and report their own initial experience in interventional procedures in 8 cases for the first time in Hungary.

Abscess↗
PubMed2000

Changes in the acute phase complement component and IL-6 levels in patients with chronic hepatitis C receiving interferon alpha-2b.

In order to study the effect of interferon alpha on the levels of acute phase complement proteins in vivo, serum concentrations of C9 and C1-inhibitor (C1-INH) were measured in patients with chronic hepatitis C before and 3 months after the beginning of interferon alpha2b therapy. Serum levels of the activation product of terminal complement pathway, C5b-9, HCV RNA and IL-6 were also determined. IFN alpha treatment significantly (P<0.0001) increased the serum concentrations of both complement proteins. C5b-9 levels were found to significantly decrease during the same period of time. When the patients were divided into responders or non-responders (more or less than 50% decrease in plasma HCV RNA concentrations) C9 and C1-INH levels were elevated only in the responder patients. There was no correlation between the changes of IL-6 levels or the amounts of IFN alpha administrated on one hand, and the changes in the complement protein levels on the other. These findings suggest that the marked increase in the serum concentrations of the acute phase complement proteins is a secondary phenomenon due to the IFN alpha-caused diminution of the viral load and the resulting immune complex-induced complement activation.

Acute-Phase Proteins↗
PubMed2000

[Open-heart surgery in Jehovah's witnesses].

The religious community Jehovah's Witnesses was founded in 1870. They hold that blood transfusion is against God's law. Surgical treatment of a Jehova witness is a great challenge for every surgeon, especially for cardiac surgeons because blood transfusion is frequently needed during such operations. Authors have been trying to reduce the utilization of preserved blood for ten years. This study is about the experience with Jehovah's Witnesses who have undergone open heart surgery in Debrecen. Twenty-four patients underwent open heart surgery from 1989 till May 1999. 7 of them were males and 17 were females. The mean age was 53 years (40-70 yrs). Three patients had congenital heart disease, 11 had acquired valve disease and 7 had coronary stenosis. In 3 cases the patients had combined coronary and valve disease. Authors used a complete procedure for reducing blood loss during the operations. Two patients (8.3%) died during the early postoperative period. Preoperative mean haemoglobin level was 134.2 g/l (112-166) and haematocrit value varied between 36-50% (mean 38%). On the first postoperative day significant decrease was registrated in these values. From the second day a slow but significant increase of haemoglobin and haematocrit levels were detected. The mean follow up time was 37.6 months (2-144), and the NYHA classification of 21 longtime survivors improved from 3.06 to 1.62. At the Department of Cardiac Surgery in Debrecen as well as worldwide more and more operations are done without blood or preserved blood products, so it could be said that nowadays surgical treatment of Jehovah's Witnesses has lower risk than before.

Adult↗
PubMed2000

[Prevalence of chronic viral hepatitis in drug abusers].

Authors examined the prevalence of hepatitis B, C and D viral infections in Hungarian drug users. Between January 1995 and October 1998 256 examinations were made (58% intravenous, 42% non intravenous drug user). Hepatitis C virus infection in 27 patients, hepatitis C and B virus infection in 4 patients, hepatitis B virus infection in 17 patients was detected. Every hepatitis B virus positive case was past infection. Hepatitis D virus infection was not detected. Clinically overt liver disease was proved in more than half of the hepatitis C virus infected patients. Because of insufficient collaboration only 11 were followed up. Liver biopsy was made in 5 cases. Interferon therapy was indicated in 3 cases. The 24% of intravenous drug users was anti-HCV seropositive contrary to 1.4% of non intravenous group. Anti-HCV seropositivity was proved in 38% in common needle users, while in disposable needle users only 3%. The prevalence of hepatitis C virus infection in intravenous drug users is rather frequent in Hungary too. The exact diagnosis of liver diseases is very difficult as for insufficient collaboration. The prevalence of hepatitis B virus infection in i.v. and non i.v. drug users is the same as in the normal population. The importance of information, especially to avoid common needle use is stressed.

Adolescent↗
PubMed2000

Image formation by bifocal lenses in a trilobite eye?

In this work we report on a unique and ancient type of eye, in which the lower surface of the upper calcite lens units possessed an enigmatic central bulge making the dioptric apparatus similar to a bifocal lens. This eye belonged to the trilobite Dalmanitina socialis, which became extinct several hundred million years ago. As far as we know, image formation by bifocal lenses of this kind did/does not occur in any other ancient or modern animal visual system. We suggest that the function of these bifocal lenses may be to enable the trilobite to see simultaneously both very near (e.g. floating food particles and tiny preys) and far (e.g. sea floor, conspecifics, or approaching enemies) in the optical environment through the central and peripheral lens region, respectively. This was the only reasonable function we could find to explain the puzzling lens shape. We admit that it is not clear whether bifocality was necessary for the animal studied. We show that the misleading and accidental resemblance of an erroneous correcting lens surface (designed by René DesCartes in 1637 [DesCartes, R. (1637). Oeuvres de DesCartes. La Géometrie. Livre 2. pp. 134. J. Maire, Leyden] to the correcting interface in the compound Dalmanitina lens may be the reason why the earlier students of the Dalmanitina lens did not recognize its possible bifocality.

Accommodation, Ocular↗
PubMed2000

New non competitive AMPA antagonists.

New halogen atom substituted 2,3-benzodiazepine derivatives condensed with an azole ring on the seven membered part of the ring system of type 3 and 4 as well as 5 and 6 were synthesized. It was found that chloro-, dichloro- and bromo-substitutions in the benzene ring and additionally imidazole ring condensation on the diazepine ring can successfully substitute the methylenedioxy group in the well known molecules GYKI 52466 (1) and GYKI 53773 (2) and the 3-acetyl-4-methyl structural feature in 2, respectively, preserving the highly active AMPA antagonist characteristic of the original molecules. From the most active compounds (3b,i) 3b (GYKI 47261) was chosen for detailed investigations. 3b revealed an excellent, broad spectrum anticonvulsant activity against seizures evoked by electroshock and different chemoconvulsive agents indicating a possible antiepileptic efficacy. 3b was found to be highly active in a transient model of focal ischemia predictive of a therapeutic value in human stroke. 3b also reversed the dopamine depleting effect of MPTP and antagonized the oxotremorine induced tremor in mice indicating a potential antiparkinson activity.

Animals↗
PubMed2000

C5b-9 and interleukin-6 in chronic hepatitis C. Surrogate markers predicting short-term response to interferon alpha-2b.

BACKGROUND: Available data and our observations suggest that elevated levels of interleukin (IL)-6 and -10 and some complement parameters may be associated with a poor response to IFN alpha. We evaluated how baseline levels of C5b-9, IL-6, and IL-10 influence the outcome of IFN alpha treatment. METHODS: Fifty-one patients with established chronic hepatitis C were enrolled and treated with IFN alpha-2b. Before and after a 12-week-IFN-treatment (3 MU or 5 MU tiw) serum levels of IL-6, IL-10, C5b-9 and RNA of hepatitis C virus (HCV) were assessed. Sera of 46 sex- and age-matched, healthy blood donors served as control. RESULTS: While two-thirds of patients was considered 'responder', 14 patients had no significant decrease either in HCV RNA or in ALT levels. In the responder's group lower baseline levels of IL-6 and C5b-9 were found than those in the 'non-responder' group. As a result of IFN therapy HCV RNA and C5b-9 levels significantly decreased. While the serum concentration of IL-6 increased during the follow-up period, regarding IL-10, no change was observed. In patients with 'low' baseline levels of C5b-9 (<2053 ng/ml) IFN alpha resulted in a significantly (P = 0.0005) higher decrease in HCV RNA level. Regarding 'low' IL-6 values (< 1.47 pg/ml) similar but somewhat less significant (P = 0.0039) difference was found if the change of HCV RNA was investigated. The odds ratio of patients with low IL-6 and/or C5b-9 to responding to IFN alpha treatment was almost 10 times (CI: 9.1 (1.8-50.9)) higher as compared with patients without 'low' levels of these parameters. CONCLUSION: Our data suggest that serum level(s) of IL-6 and/or C5b-9 taken prior to the initiation of IFN treatment may serve as surrogate marker(s) in evaluating patients with chronic hepatitis C whether to get IFN alpha in monotherapy or to consider having combination therapy in the form of IFN alpha-ribavirin.

Adult↗
PubMed1999

[Prevention of atrial fibrillation by atrial-based pacemaker implantation].

A large number of studies have demonstrated the long term disadvantage of single lead ventricular pacing in sick sinus syndrome. Ventricular pacing mode predicts chronic atrial fibrillation in patients with preimplant paroxysmal atrial fibrillation. The goal of the report was to study the effectiveness of single atrial and dual chamber (atrio-ventricular sequential) pacemaker treatment in the prevention of atrial fibrillation for patients with sick sinus syndrome complicated with paroxysmal atrial fibrillation. In our university hospital 16 atrial based 5 and dual chamber 11 pacemaker were implanted for treatment of patients with sick sinus syndrome (with or without AV conduction disturbances) complicated with paroxysmal atrial fibrillation. The mean age were 61 (24-78), nine males and seven females. Before or during pacemaker implantation sinus node and AV node function analysis, and echocardiography were performed. There were no surgical complications, lead and/or generator failure. All patients had routine follow-up performed at 4 weeks, 3 months, 6 months. Mean follow up was 31 +/- 8 months (range 3 to 93 months). The atrial based and dual chamber pacing were effective in 90% of our cases. In one patient the treatment had to be combined with propafenone. According to our result, the atrial based pacing may be used to reduce the incidence of atrial fibrillation with careful programming of the base atrial pacing rate, and it is associated with lower frequencies of thromboembolic complications and pacemaker syndrome.

Arrhythmias, Cardiac↗
PubMed1999

On the mechanism of cogenotoxic action between ingested amphibole asbestos fibres and benzo[a]pyrene: II. Tissue specificity studies using comet assay.

Epidemiological data seem to be equivocal on the probable increase in cancer incidence in populations exposed to asbestos-fibre contaminated drinking water. Although animal experiments failed to demonstrate carcinogenicity of oral asbestos exposure, the large surface area of the fibres, however, creates the possibility of cogenotoxic action with adsorbed water-borne organics. In our animal model, rats were gavaged with untreated UICC crocidolite and anthophyllite fibres and fibres that had been allowed to adsorb benzo[a]pyrene molecules from aqueous solutions. Peritoneal macrophages and intestine, parietal peritoneum and omentum samples were obtained from the animals after 24 h. The alkaline single-cell microgel electrophoresis assay (comet assay) was performed on cells isolated from the solid tissues. Tail moment was applied as a basis of evaluation following image analysis. Our results indicate high levels of DNA strand breaks in the cells prepared from the omentum and intestine. We could also demonstrate a significant potentiating effect of the adsorbed carcinogen on the induction of DNA damage in the omentum. The parietal peritoneum and macrophages were not involved in the early genotoxic alterations under study. Our results support the molecular model of asbestos cocarcinogenesis, including both asbestos-induced deletions and mutations caused by a mutagen carried by the same fibres.

Animals↗
PubMed1999

Lack of anticholinergic effect of N(G)-nitro-L-arginine methylester in the small intestine.

The nitric oxide (NO)-synthase inhibitor, N(G)-nitro-L-arginine methylester (L-NAME), has been reported to have an atropine-like action. We compared the effects of L-NAME (1 mM) and atropine on isolated small intestinal preparations of the guinea-pig, rat, rabbit and mouse. Half-maximal longitudinal contractions in response to acetylcholine (50-100 nM) were not influenced by L-NAME, but were strongly suppressed by atropine (1 nM). Cholinergic 'twitch' contractions of the guinea-pig ileum were slightly enhanced by L-NAME; this effect was prevented by pretreatment with N(G)-nitro-L-arginine (L-NOARG, 100 microM), another NO synthase inhibitor. 'Twitch' contractions were concentration dependently inhibited by atropine (1-100 nM). We conclude that L-NAME is free of atropine-like activity in isolated intestinal preparations.

Acetylcholine↗
PubMed1999

Effect of intrathecal agmatine on inflammation-induced thermal hyperalgesia in rats.

Agmatine, an endogenous ligand, interacts both with the alpha2-adrenoceptors and with the imidazoline binding sites. The effect of intrathecally administered agmatine on carrageenan-induced thermal hyperalgesia was investigated by means of a paw-withdrawal test in rats. The effect of agmatine on morphine-induced anti-hyperalgesia was also studied. Intrathecal agmatine in doses larger than 250 microg caused a decrease in the pain threshold, with vocalization and agitation lasting for several hours in all animals. Agmatine alone at 1-100 microg did not give rise to any change in the thermal withdrawal threshold in the contralateral non-inflamed paw. Agmatine pretreatment was found to dose-dependently attenuate the thermal hyperalgesia induced by intraplantar carrageenan. The effect of 100 microg agmatine was completely lost by 60 min, whereas the effect of 50 microg was of similar magnitude but exhibited a longer duration. Agmatine posttreatment had a slighter effect. Agmatine pretreatment (100 microg) together with 1 microg morphine (subeffective dose) has significantly higher anti-hyperalgesic effect then the individual compounds by themselves. These are the first data demonstrating the behavioral and anti-hyperalgesic effects of intrathecal agmatine. The results reveal important interactions between intrathecal agmatine and opioids in thermal hyperalgesia.

Agmatine↗
PubMed1999

[Surgical treatment of mitral insufficiency using annuloplasty suture technic].

In 1991 a simple and cheap technique was introduced for mitral valve repair at our department. After repairing the mitral leaflets, where indicated a posterior leaflet annuloplasty was performed with a semicircular suture and the annulus fixed for the appropriate size by tying the stitch. Between July 1991 and December 1995 86 patients underwent the above procedure (average age 56.8 +/- 10.4 years). 45 patients had primary mitral valve disease (myxomatous degeneration, rheumatoid disease, endocarditis), the other 41 had functional mitral regurgitation secondary to severe aortic valve or coronary artery disease. Echocardiography showed severe mitral regurgitation in 77% of the patients. In 45 cases the mitral valve itself was also repaired (valvotomy, quadrangular resection, wedge resection, etc.) in 29 cases the aortic valve was replaced as well, while 24 patients required additional revascularisation of the myocardium. The 30 day mortality was 3.5%. One week after surgery echocardiography was performed at all patients and showed acceptable mitral valve area (2.28 +/- 0.39 cm2). In 28 cases mild mitral regurgitation was found, the other valves were competent. All but 3 patients were followed up (96.4%). There were 6 late deaths (3 cardiac, 2 non cardiac, 1 embolic, 7.2% late mortality). During the follow up period (31.7 +/- 11.2 months) 5 patients required mitral valve replacement for severe recurrent mitral regurgitation (6.0%). In two cases new chorda rupture caused the recurrence, in an other case the suture had torn out of the annulus due to inadequate surgical technique. In the last two cases the annulus had dilated with intact Prolene annuloplasty stitch present, 86.8% of the survivors were in NYHA class I. or II. Our results suggest that mitral valve repair in selected cases can be performed without using expensive annuloplasty rings. The suture used for annuloplasty should be strong, non absorbable and non stretchable. Since 1994, when we started using GoreTex suture instead of Prolene no more patients required reoperation for annuloplasty failure.

Adult↗
PubMed1999

[The role of CT examination in the diagnosis and therapy of chronic thoracic empyema].

Successful surgical treatment of chronic intrathoracic suppuration can, in the substantial majority of cases, be accomplished only by means of major surgery or a series of thoracic operations. If a solution to the chronic process cannot be provided by decortication of the lung, or should decortication not be possible due to the moribund condition of the patient, successful treatment can still be achieved through thoracic fenestration. 314 patients were treated for chronic suppuration in the thoracic cavity between 1st January 1987 and 31st December 1997. Of these, ten died, this representing a mortality rate of 3.1%. Seven of these ten patients suffered chronic suppuration. The total number of patients suffering chronic suppuration was 73 (23.2%). Of these 73 patients, in 31 cases treatment involving two or more surgical intervention procedures was performed. Three of the ten patients on whom open surgery was performed died, these having been referred to the department already in a moribund condition. It was decided that prolonged open surgery should be performed on three patients. CT examination enables the position of the empyema, the depth of the callus surrounding it, the position of drains and the relation between the visceral pleura and the pulmonary parenchyma and their demarcation to be determined prior to open surgery with greater precision than by any other diagnostic technique developed previously. CT examination has acquired a fundamental role, subsequent to partial resection or pneumonectomy, in the examination of the bronchial trunk and in the detection of fistulae. Following open surgery CT is also appropriate for the evaluation of the dimensions of the cavity, its form, the depth of granulation tissue, retraction of the bony thoracic structure and the condition of the bronchial stump. Where there is a precedent of tumours it can provide assistance in the detection of recurrence, lymph node conditions or metastasis. Complications arising subsequent to surgery (bronchial fistula, recurrent empyema, etc.) can thus be detected in due time. Prior to thoracoplasty or myoplasty the condition of the myocutaneous lobe twisted on a neurovascular spindle and sealing the cavity can be examined clearly by means of CT, as can the viability of the transposed skin and the muscle fascicle subsequently.

Adolescent↗
PubMed1999

Simultaneous determination of dimethylarsinic acid and monomethylarsonic acid after derivatization with thioglycol methylate by gas chromatography/mass spectrometry.

A gas chromatography/mass spectrometry (GC/MS) method has been developed to determine two methylated arsenic species in human urine samples. The yield of derivatization for dimethylarsinic acid (DMA) and monomethylarsonic acid (MMA) using thioglycol methylate (TGM) was measured. The detection limit for the derivatized DMA and MMA using the GC/MS method are 0.95 and 0.8 ng cm-3, respectively. This simple and rapid method has good precision and accuracy. Fragmentation routes of derivatized MMA and DMA are suggested on accurate mass measurements.

Arsenicals↗
PubMed1999

Preparation and primary evaluation of [11C]CSC as a possible tracer for mapping adenosine A2A receptors by PET.

A 11C labeled selective adenosine A2A antagonist, (E)-8-(3-chlorostyryl)-1,3-dimethyl-7-[11C]methylxanthine [11C]CSC) was prepared by the reaction of (E)-8-(3-chlorostyryl)-1,3-dimethylxanthine and [11C]methyl iodide. The decay-corrected radiochemical yield was 32.3% with a radiochemical purity of 99%, a specific activity of 1.85-5.55 GBq/mumol and a preparation time of 1 h. A primary evaluation of [11C]CSC as a potential tracer for mapping adenosine A2A receptors by positron emission tomography (PET) is also presented. Biodistribution and autoradiographic studies were carried out on Swiss mice and domestic rabbits. In mice the lung showed the highest uptake at 10 min after i.v. injection, followed by the liver, kidney, heart and brain. Inside the brain a high level of radioactivity accumulated in the striatum, in accordance with previous findings on the specific spatial distribution of A2A adenosine receptors and also in the medulla oblongata. Dynamic PET studies on rabbits showed a fast brain uptake of CSC, reaching a maximum in less then 2 min. On the basis of competition experiments with the unlabeled ligand [11C]CSC proves to bind specifically to the appropriate receptor.

Animals↗
PubMed1999

The role of CT examination in diagnostics and surgery of chronic empyema thoracis.

Computer tomography (CT) has become one of the most important modern diagnostic procedure in the detection, differential diagnosis, treatment and the postoperative follow up of patients suffering from chronic intrathoracic suppuration. Although CT examination is nowadays almost unlimitedly available it is still not regarded as a routine diagnostic procedure. It proves to be remarkably useful in the surgical treatment of neglected, chronic cases of suppuration in the thoracic cavity. On the basis of the Moores empyema thoracis classification [3] patients in the third stage belong to the group with chronic intrathoracic suppuration. Their empyema can only be treated by a major surgery or a series of operations.

Adolescent↗