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Biomedical subjects

G Horváth

Publications and source records attributed to G Horváth.

At least 19 recordsLinked to original sources
PubMed1992

[Incidence of hepatitis B, C and D infection in chronic liver diseases].

The authors tested hepatitis B (HBsAg, anti-HBs, anti-HBc, IgM anti-HBc, HBe, anti-HBe), C (anti-HCV) and D (anti-HD, IgM anti-HD) virus markers in the sera of 204 patients, who suffered from histologically confirmed chronic liver diseases (age: 18-72, average: 46.8 y) by Sorin Biomedica RIA and Abbott ELISA kits. On the basis of detailed virus serological tests, they obtained data indicating viral etiology in 62% of the cases. 33.3% of the patients were anti-HCV, 52.5% of the patients were HBV marker seropositive and 11.2% of the HBV seropositive cases were anti-HD seropositive. In 2% of the cases seropositivity of all the three viruses was proved. In 26% of the patients seropositivity of two viruses (HBV and HCV, or HBV and HDV) was proved. They observed severe, progressing liver diseases in patients with HBV, HCV and HDV marker seropositivity in a higher ratio than in seronegative patients. In the cases of combined virus marker seropositivity the incidence rate of chronic hepatitis and liver cirrhosis was higher than in only HBV marker seropositive patients, but did not differ significantly from those only anti-HCV seropositive. In the cases of fought-off HBV infection the severity of the liver disease was milder than in the cases of replication and integration stage. Anti-HD seropositivity occurred in all stages of HBV infection, but active HDV infection, in most of the cases, was observed only in cases in the integration stage. Anti-HCV seropositivity was observed mainly in the fought-off HBV infection stage. Their results suggest that HCV infection, like HDV infection, may suppress HBV replication.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1992

[Clinical significance of the hepatitis Delta virus and its incidence in virus B positive chronic liver diseases].

The data on hepatitis delta virus and the liver diseases caused by it are reviewed. The findings of hepatitis B and D virus markers in 118 hepatitis B virus seropositive patients suffering from histologically confirmed chronic liver disease are reported. The prevalence of hepatitis delta virus infection was 13.56% of these cases, while active hepatitis delta virus replication was proved in 6 cases of them. Based on their findings, the role of hepatitis delta virus in the progression of chronic liver diseases is concluded, similarly to data published earlier. The importance of repeated, detailed virus-serological and histological examinations is stressed, especially in the cases in which the progression of liver disease are detected. The authors suggest that HBsAg--IgM complex seropositivity in patients suffering from anti-delta seropositive chronic liver disease supports active hepatitis delta virus infection.

Biomarkers↗
PubMed1992

[Significance of detailed Hepatitis B virus marker studies in chronic liver diseases].

The hepatitis B virus (HBV) markers were studied by Sorin RIA kits in the sera of 390 patients suffered from histologically confirmed chronic liver disease. On the base of HBsAg, anti-HBs, anti-HBc seronegativity the HBV infection was excluded in 235 cases. In most HBV negative cases the diagnosis was fatty liver and alcoholic hepatitis (52%), while chronic active hepatitis and/or liver cirrhosis occurred only in 21.7% of patients. Past or present HBV infection was proved in 155 patients. The diagnosis of 52.9% of cases in this group was chronic active hepatitis and/or liver cirrhosis, while fatty liver and alcoholic hepatitis occurred in 27.7%. The detailed HBV marker analysis was performed in 76 patients. Previous infection without replication (anti-HBs and/or anti-HBc and/or anti-HBe positivity) was proved in 48 cases, 12 patients have active HBV infection (HBsAg, HBe, IgM anti--HBc, positivity), while in 16 cases integrated HBV infection (HBsAg, anti-HBc, anti-HBe positivity) was proved. The HBsAg--IgM complex seropositivity was detected in every case with active HBV replication. Because of therapeutic, prognostic and epidemiologic significances the detailed HBV serology in chronic liver diseases is stressed.

Adolescent↗
PubMed1992

Pharmacokinetic and metabolism studies on girisopam by chromatographic and spectrometric methods in humans.

Girisopam possesses selective anxiolytic action without muscle relaxant and anticonvulsive activity. After a 100-mg oral dose of 14C-labelled girisopam to seven male subjects, the mean recovery of 14C radioactivity was 51% in urine and 33% in faeces. A high-performance liquid chromatographic method has been developed for studying girisopam in single-dose pharmacokinetic studies. The serum extract was chromatographed on a normal-phase column using a mobile phase of hexane-ethanol-diethyl ether (66:9:25, v/v) and ultraviolet detection at 235 nm. The recovery was 60% and the detection limit was 3 ng/ml, using 1 ml of serum. After a 20-min delay, girisopam is rapidly absorbed. After reaching a mean serum level of 178 ng/ml at a mean time of 2.0 h, the serum concentration of girisopam decreased with a mean elimination half-time of 22.2 h. The metabolites were separated by high-performance liquid chromatography, radio thin-layer chromatography and gas chromatography. Their structures were determined by liquid chromatography-mass spectrometry, mass spectrometry and gas chromatography-mass spectrometry. Their chemical structures were confirmed by comparison with synthesized reference compounds. The major urinary metabolites were 7-demethylgirisopam (I), 4'-hydroxygirisopam (II) and 4-hydroxymethyl-4-demethylgirisopam (III), which were in conjugated form, and 4-carboxy-4-demethylgirisopam (V), a compound with an open-chain structure (VII) and traces of 4-demethyl-4-oxogirisopam (VIII) and 4-hydroxymethyl-4-demethylgirisopam (III), which were in non-conjugated form. The metabolic profile in the serum consisted predominantly of the glucuronides of I, II and III. The non-conjugated metabolites were the metabolite with the open-chain structure (VII), III and V. Besides the parent compound, the faeces sample contained conjugates of I and II.

Adult↗
PubMed1992

Influence of oligopeptide aldehydes on intracellular Ca2+ concentration in rat pituitary cells.

We investigated the effects of some synthetic tripeptide aldehydes, earlier shown to influence pituitary hormone secretion and 45Ca2+ uptake, on the intracellular free Ca2+ concentration ([Ca2+]i) of rat anterior pituitary cells in suspension. Boc-D-Phe-Leu-Phenylalaninal or Boc-D-Phe-Leu-Prolinal in the tested range of 1-100 or 200 microM, respectively, were ineffective in influencing basal [Ca2+]i but caused a concentration-dependent inhibition in K+ (25 mM)-induced [Ca2+]i elevation. The IC50 of both effects was about 50 microM. In contrast, they did not interfere with the stimulation caused by the calcium channel agonist BAY K 8644 and were also ineffective in influencing the receptor-mediated stimulus of thyrotropin-releasing hormone on [Ca2+]i. On the basis of the present and foregoing results the possible involvement of calcium channels is discussed, but different mechanisms mediating the tripeptide aldehyde inhibition are also considered. A third tripeptide aldehyde, Boc-Gln-Leu-Lysinal (Boc-GLL), showed ionophore-like properties. This nontoxic substance caused a dose-dependent rise up to 400% (at 100 microM) in [Ca2+]i. Its effect is not mediated by voltage-dependent calcium channels, as it cannot be inhibited either by the classical calcium channel antagonists verapamil and nifedipine, or by the above-mentioned inhibitory tripeptide aldehydes. When we decreased the extracellular Ca2+ concentration by the addition of 4 mM EGTA, the effect was inverted and Boc-GLL caused a large fall in [Ca2+]i. We suggest that Boc-GLL may open cell membrane pores through which Ca2+ moves along the concentration gradient.(ABSTRACT TRUNCATED AT 250 WORDS)

3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethy↗
PubMed1992

An isobolographic analysis of the hypnotic effects of combinations of dexmedetomidine with fentanyl or diazepam in rats.

The effects of the combinations of dexmedetomidine-fentanyl and dexmedetomidine-diazepam on the righting reflex were studied in rats. The doses that block the righting reflex for the agents given alone and for their combinations were determined with a probit procedure and compared with an isobolographic analysis. The interactions between dexmedetomidine and fentanyl or diazepam were found to be synergistic. In the dexmedetomidine-diazepam combination studies, less than one-fourth of the single drug dose (for each of two agents) was needed to produce the required effect. These data confirm synergistic interactions between dexmedetomidine and fentanyl or diazepam in producing hypnotic-anesthetic action.

Anesthetics↗
PubMed1992

Potentiated hypnotic action with a combination of fentanyl, a calcium channel blocker and an alpha 2-agonist in rats.

An investigation was made of the hypnotic-anaesthetic effects in rats of subcutaneous coadministration of fentanyl (25-100 micrograms.kg-1), clonidine (100-300 micrograms.kg-1) and verapamil (1-5 mg.kg-1). Hypnotic-anaesthetic efficacy was assessed via loss of the righting reflex. In the doses used, none of the three drugs alone was associated with appreciable hypnotic-anaesthetic effects. Coadministration of fentanyl and clonidine resulted in a dose-related enhancement of the anaesthetic potency, without change in the duration of hypnotic action. Verapamil coadministration failed to increase the anaesthetic efficacy of binary combinations of fentanyl and clonidine, but a marked prolongation of the duration of hypnotic action was observed (P less than 0.001). These results suggest the existence of unreported interactions between these three drugs in the production of hypnotic-anaesthetic action in rats.

Adrenergic alpha-Agonists↗
PubMed1992

Isolation and structure elucidation of new antibiotics related to angolamycin.

Angolamycin (1) and two novel analogues (2 and 3) were isolated from the culture broth of a Streptomyces strain. NMR and MS analysis proved that 2 is the 18-dihydro-, while 3 is the 18-deoxo-18-dihydro derivative of angolamycin. Full experimental assignment of the 1H and the 13C NMR spectra of these compounds was obtained from 1D and 2D chemical shift correlation measurements. Compounds 2 and 3 are less potent antibiotics than angolamycin.

Anti-Bacterial Agents↗
PubMed1992

[Survey of the analysis of selegiline].

The characteristics of the selegiline active substance, identification tests, purity tests and the determinations of the active substance content are summarized in the paper. Fast, simple, selective reverse phase HPLC method is used for purity tests and active substance determinations. The validation of the determination of the active substance and the purity test is presented. The solvent residues were determined in vapour phase by the headspace method. A potentiometric acidi-alkalimetric titration, carried out in nonaqueous solution with the application of a titriprocessor is applied as an assay. A thermoanalytical method developed for the purity determinations is also published in this issue by Ladányi et al.

Chromatography, High Pressure Liquid↗
PubMed1991

The effect of the conformer state and the model size chosen on the force field of the polypeptide backbone.

We have attempted to check the validity of our previously calculated ab initio force field for the polypeptide backbone, for the variance with conformer state and model size chosen. For the previous problem we applied our usual ab initio Hartree-Fock SQM method, also used at the original development of the force field, while for the latter we utilized the semiempirical MNDO CO-gradient method. It is shown that the in-plane force field is reasonably stable for change of conformational state, while the out-of-plane force field can be assigned good average guess values. The effect of the model size is shown to be moderate upon introducing a dipeptide into a polymer chain.

Alanine↗
PubMed1990

A phase II study of toremifene in carcinoma corporis uteri. Preliminary communication.

A phase II study of toremifene was started in patients suffering from advanced carcinoma corporis uteri. Minimum duration of treatment was 3 months but with stabilized disease (SD) and remission the treatment is to be continued as long as the treatment response lasts. At present four patients with recurrent carcinoma corpus uteri have been included. Dose level of toremifene is 200 mg per day. At 12 weeks one of the patients has partial remission (PR), two have SD and one progressive disease (PD). There have been no unacceptable side effects.

Adenocarcinoma↗
PubMed1990

[Value of the Medicor CT 0100 equipment in a county hospital in the diagnosis of cerebrovascular diseases].

Data of patients with CVD in the ward of the authors in the last quarters of 1986 and 1987 has been compared, in the second period they used a MEDICOR CT 0100 computer tomograph. The subsequent results are stressed: The rate of the patients with CVD in the Department of Neurology was approximately 40% in the studied period. 88-90% of all lethal cases has been covered by this patients's group. Half of the patients with CVD was between 50-70% years, however younger age was more common among men. The majority of CVD was ischaemic. In vivo diagnosis of intracerebral bleeding has been markedly increased after introduction of CT investigation. CT scan on the first three days is helpful to localise the source of the subarachnoideal bleeding, however can not replace the angiography in the cases indicated for operation. Investigations by angiography have decreased to the one third in the department without neurosurgery after introducing CT however their indication has been changed. In traumatic cases CT is more informative and more sparing. Diagnoses suggested by neurologists have been confirmed by the CT in 69%.

Cerebrovascular Disorders↗
PubMed1990

Geometric optical investigation of the underwater visual field of aerial animals.

The underwater visual field distorted by refraction for aerial animals living near the water surface is investigated by means of geometric optics. The imaging of underwater objects by one and two aerial eyes is studied. The underwater binocular image field is determined for pairs of aerial eyes placed in horizontal and vertical planes. Some possible biooptical consequences of the visual detection of underwater prey and predator by aerial animals are discussed on the basis of the structure of their distorted visual field.

Animals↗
PubMed1990

Inflammatory pseudotumour of the liver.

In view of their own case, authors review the diagnostic and clinical characteristics of the inflammatory "pseudotumours" of the liver. They state that this liver disease is important from the differential diagnostic point of view. The inflammatory pseudotumours should be basically differentiated from malignant tumours in which the imaging procedures and their repetition are significant. Authors review their case in connection with 13 cases collected from the literature.

Aged↗
PubMed1990

Factors influencing the operation of a vertical bioreactor segmented with perforated plates.

Factors influencing the operation of a vertical bioreactor segmented with perforated plates supporting immobilized yeast cells were studied. It was found that the most important factors are the length-diameter (L/D) ratio of the reactor and the dilution rate. It was supposed that the optimal L/D ratio is about 1. The operation of the reactor was more favourable at a low liquid phase-solid phase ratio. The spatial distribution of the biocatalyst had only a slight, if any effect. The periodically changed direction of feed flow has no improving effect on the fermentation process.

Cell Division↗
PubMed1990

Enhancement of fentanyl analgesia by clonidine plus verapamil in rats.

An investigation was made of the analgesic effects of the subcutaneous coadministration of fentanyl, an opioid mu-agonist (15 micrograms/kg), clonidine, an alpha 2-agonist (100 micrograms/kg), and verapamil, a calcium channel blocker (10 mg/kg) in rats. Nociceptive sensitivity was assessed with hot-plate and tail-flick techniques. None of the three drugs alone was associated with appreciable analgesic effects in the doses used. The simultaneous administration of the three drugs resulted in marked analgesia superior to that of all binary combinations of these drugs. Two-way analysis of variance showed statistically significant differences in hot-plate and tail-flick latencies after drug treatments (P less than 0.001). The significant differences in the area under the time-response curve values (P less than 0.001) might indicate not only an increased analgesic effect, but also a prolongation of antinociception. These results suggest the existence of hitherto unreported interactions between drugs involved in the production of analgesia.

Animals↗
PubMed1989

Geometric optical optimization of the corneal lens of Notonecta glauca.

The optimal shape of the corneal lens of the water bug backswimmer (Notonecta glauca) and the optimal shape and position of the thin transition layer between the distal and proximal units of its cornea are theoretically determined. Using a geometric optical method, first the shape of a geometric interface between the lens units is determined, which eliminates the longitudinal spherical aberration. This interface is investigated for differently formed thick lenses when the medium in contact with the entrance surface of the lens is water or air. The optimal transition layer for the amphibious backswimmer is that, the boundaries of which are the theoretical interfaces for water and air, and the refractive index varies continuously in it. The optimal shape of the corneal lens is determined, with the disadvantageous lenses, with respect to the possible minimal spherical aberration and amount of reflected light from the transition layer, being rejected. The optimal position of the transition layer in the cornea can be obtained from the minimization of the amount of diffracted light on the marginal connection of the layers. The optimal corneal lens for backswimmer has ellipsoid boundary surfaces; the optimal transition layer in it is thin bell-shaped, at the marginal connection of which there is no dimple, the maximum of the layer is on the margin of the cornea. The shape of the theoretically optimal corneal lens, the shape and position of the theoretically optimal transition layer agree well with those of Notonecta glauca. The question posed, the geometric optical method used and the results presented are of general importance, and not only with respect to vision in the bug Notonecta, but also in the fossil trilobites, or in the wave guide theories which have been employed in similar modelling problems, in design of system of lenses without spherical aberration, for example.

Amphibians↗