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Biomedical subjects

A Juhász

Publications and source records attributed to A Juhász.

At least 19 recordsLinked to original sources
PubMed2006

Histamine-induced enhancement of vasopressin and oxytocin secretion in rat neurohypophyseal tissue cultures.

The effects of histamine (HA) on vasopressin (VP) and oxytocin (OT) secretion were studied in 13-14-day cultures of isolated rat neurohypophyseal (NH) tissue. The VP and OT contents of the supernatant were determined by radioimmunoassay (RIA) after a 1 or 2-h incubation. Significantly increased levels of VP and OT production were detected in the tissue culture media following HA administration, depending on the HA dose. The elevation of NH hormone secretion could be partially blocked by previous administration of the HA antagonist mepyramine (MEP, an H1 receptor antagonist) or cimetidine (CIM, an H2 receptor antagonist). Thioperamide (TPE, an H3-H4 receptor antagonist) did not influence the VP or OT secretion increase induced by HA. The application of MEP, CIM or TPE after HA administration proved ineffective. The H1 and H2 receptors are mainly involved in the HA-induced increase of both VP and OT secretion in isolated NH tissue cultures. The results indicate that NH hormone release is influenced directly by the histaminergic system, and the histaminergic control of VP and OT secretion from the NH tissue in rats can occur at the level of the posterior pituitary.

Animals↗
PubMed2006

The influence of root canal shape on the sealing ability of two root canal sealers.

AIM: To evaluate the influence of root canal form on the sealing ability of two root canal sealers. METHODOLOGY: Twenty radiographically confirmed straight and 20 curved root canals were prepared with a stepback hand filing technique. Root canal aberrations created during preparation were determined by the use of double exposure radiographic technique. The prepared canals were filled with lateral condensation of gutta-percha and one or other of two root canal sealers (Pulp Canal Sealer and Sealapex). Leakage along the apical 10 mm of roots was measured with a fluid transport model at 1, 3, 6, 9 and 12-month intervals. RESULTS: There were no statistically significant differences between straight and curved root canals (P > 0.05) for prevalence of root canal transportation. The prevalence of apical transportation was 80% in the straight and 85% in the curved root canals. A complete seal was more frequently observed in straight canals compared with curved canals. Utilizing the pi* index, analysis showed the filling with Sealapex allowed more leakage than Pulp Canal Sealer at 1 year. CONCLUSION: Under the conditions of the study, root canal form influenced short-term sealing ability. In the long-term the seal was affected by the sealer rather than root canal form.

Analysis of Variance↗
PubMed2006

Influence of the N-acetylation polymorphism on the metabolism of talampanel: an investigation in fasted and fed subjects genotyped for NAT2 variants.

Talampanel is a 2,3-benzodiazepine-type allosteric (noncompetitive) AMPA-antagonist currently being developed as an orally active, broad-spectrum anticonvulsant. Here, a detailed study of its N-acetylation in humans is presented using plasma concentration data of both TLP and its N-acetyl metabolite obtained from healthy volunteers (n = 28) genotyped for N-acetyltansferase NAT2 isozymes. Plasma samples were obtained for up to 48 h after a single oral dose of 75 mg TLP both in fasted and in fed subjects. A perfect correspondence could be established between the phenotype inferred before the study from genotyping and that determined after the study by using plasma metabolite-to-parent molar ratios confirming that this route of metabolism is indeed mediated by NAT2. Analysis of the data has been performed using both noncompartmental analysis and a custom-built, unified parent-metabolite PK model, which incorporates three different acetylation rates according to the genotype-based classification of each subject as slow, intermediate, or fast acetylator to simultaneously fit plasma levels for both TLP and its metabolite. This suggest that for TLP in humans, (i) N-acetylation represents only a relatively small fraction of its total elimination (about one-fourth in fast acetylators and much less in slow acetylators), (ii) acetylation is about eight-twelve times faster in fast and three-six times faster in intermediate acetylators than in slow acetylators, and (iii) the N-acetyl metabolite is eliminated faster than the parent TLP.

Acetylation↗
PubMed2005

Serotonin-induced enhancement of vasopressin and oxytocin secretion in rat neurohypophyseal tissue culture.

The effects of serotonin (5-hydroxytryptamine; 5-HT) on vasopressin (VP) and oxytocin (OT) secretion were studied in 13-14-day cultures of isolated rat neurohypophyseal (NH) tissue. The VP and OT contents of the supernatant were determined by radioimmunoassay after a 1 or 2 h incubation. Significantly increased levels of VP and OT production were detected in the tissue culture media following 5-HT administration, depending on the 5-HT dose. The elevation of NH hormone secretion could be partially blocked by previous administration of the 5-HT antagonist ketanserin or metergoline. WAY-100635 did not influence the increased VP secretion induced by 5-HT, but the elevated OT production was prevented by WAY-100635 before 5-HT administration. The application of WAY-100635, ketanserin or metergoline, after 5-HT administration proved ineffective. The results indicate that NH hormone release is influenced directly by the serotonergic system. The serotonergic control of VP and OT secretion from the NH tissue in rats can occur at the level of the posterior pituitary.

Animals↗
PubMed2005

Genotypic distribution of human herpesvirus-8 strains circulating in HIV-positive patients with and without Kaposi's sarcoma in Hungary.

Open reading frame (ORF) 26 of human herpesvirus-8 (HHV-8) from peripheral blood samples of 15 Hungarian HIV-positive patients with or without Kaposi's sarcoma (KS) were amplified and sequenced. Four variants of HHV-8 were identified according to ORF 26 genotyping. Most of the samples were shown to be subtype A3, however, subtypes A, B3/C2/C2', and C3 (ORF 26 region) were also identified. The ORF 26 subtypes A and C3 of HHV-8 were only recovered from patients with KS while A3 was dominant in KS negative cases. The amplification of the hypervariable ORF K1 gene was successful only from 2 of the same 15 patients. Sequence analysis of the amplified ORF K1/VR1 regions identified subtype A3 from 2 patients with AIDS-associated KS. A novel ORF K1/VR1 variant belonging to subgroup A' was detected in a different sample in one of them. Amplification of the ORF K15, another representative locus for HHV-8 genotyping, was not successful from any of the peripheral blood samples. Unsuccessful amplification of the terminal K1 and K15 ORFs from peripheral blood samples suggests that KS biopsy specimens are needed for complete genotyping of HHV-8 strains from Hungary.

Acquired Immunodeficiency Syndrome↗
PubMed2005

Gene expression profile analysis of lymphocytes from Alzheimer's patients.

Since the function and metabolism of peripheral lymphocytes is known to be altered in Alzheimer's disease (AD), a pilot study was carried out to examine differences in gene expression profiles of these cells in 16 AD patients and aged control probands. Using a cDNA microarray representing 3200 distinct human genes, we identified 20 candidate genes whose expression is altered in AD lymphocytes compared with the control probands. Among these were the alpha2C-adrenoreceptor gene, known to regulate blood pressure and learning, the defensin, histocompability complex enhancer-binding protein, carboxypeptidase M, and the Fc fragment of IgE known to be involved in cellular and humoral immune responses. Others, like human cell death protein, TRAIL, and galectin-4 participate in the regulation of apoptosis. Real-time quantitative reverse transcription-polymerase chain reaction analysis was performed in order to confirm the expression changes in AD lymphocytes, and it could detect down-regulation of defensin and alpha2c-adrenoceptor genes, while other genes seemed unaltered in their expression, including heat-shock protein (hsp90), cholesteryl ester transfer protein, and apolipoprotein B100 (apoB). The altered expression profile of these genes might be connected with the previously reported AD-specific lymphocyte abnormalities. It remains to be elucidated, however, how these genes are related to the pathomechanism of dementia and whether the gene expression differences of AD lymphocytes reflect disease traits or stage processes.

Aged↗
PubMed2005

High co-prevalence of genogroup 1 TT virus and human papillomavirus is associated with poor clinical outcome of laryngeal carcinoma.

BACKGROUND: The aetiology and factors leading to the progression of laryngeal cancer are still unclear. Although human papillomavirus (HPV) has been suggested to play a role, reports concerning the effect of HPV infection on tumour development are controversial. Recently, transfusion transmitted virus (TTV) was suggested to play a role in certain infections as a causative or coinfecting agent. AIMS: To investigate whether the development and progression of laryngeal squamous cell carcinoma is associated with coinfection with TTV and HPV. METHODS: The prevalence of TTV and HPV was investigated using the polymerase chain reaction in tissue samples from 40 healthy individuals, 10 patients with recurrent papillomatosis, five patients with papillomatosis with malignant transformation, and 25 patients with laryngeal carcinoma. The obtained prevalence data were compared and analysed statistically. RESULTS: In the 11 patients with carcinoma who had metastasis or relapse there was a high rate of coinfection with genogroup 1 TTV and HPV (eight of 11), whereas in the 14 without tumour progression no coinfection was found. Coinfection was associated with significantly lower tumour free survival in patients with carcinoma (p < 0.001). Furthermore, four of five patients who had papillomatosis with malignant transformation were coinfected with genogroup 1 TTV and HPV. CONCLUSIONS: Although the nature of cooperation between HPV and TTV needs to be investigated further, coinfection with genogroup 1 TTV and HPV appears to be associated with poor clinical outcome in laryngeal cancer.

Adolescent↗
PubMed2004

Dissemination of the highly expressed Bx7 glutenin subunit (Glu-B1al allele) in wheat as revealed by novel PCR markers and RP-HPLC.

Increased expression of the high molecular weight glutenin subunit (HMW-GS) Bx7 is associated with improved dough strength of wheat (Triticum aestivum L.) flour. Several cultivars and landraces of widely different genetic backgrounds from around the world have now been found to contain this so-called 'over-expressing' allelic form of the Bx7 subunit encoded by Glu-B1al. Using three methods of identification, SDS-PAGE, RP-HPLC and PCR marker analysis, as well as pedigree information, we have traced the distribution and source of this allele from a Uruguayan landrace, Americano 44D, in the mid-nineteenth century. Results are supported by knowledge of the movement of wheat lines with migrants. All cultivars possessing the Glu-B1al allele can be identified by the following attributes: (1) the elution of the By sub-unit peak before the Dx sub-unit peak by RP-HPLC, (2) high expression levels of Bx7 (>39% Mol% Bx), (3) a 43 bp insertion in the matrix-attachment region (MAR) upstream of the gene promoter relative to Bx7 and an 18 bp nucleotide duplication in the coding region of the gene. Evidence is presented indicating that these 18 and 43 bp sequence insertions are not causal for the high expression levels of Bx7 as they were also found to be present in a small number of hexaploid species, including Chinese Spring, and species expressing Glu-B1ak and Glu-B1a alleles. In addition, these sequence inserts were found in different isolates of the tetraploid wheat, T. turgidum, indicating that these insertion/deletion events occurred prior to hexaploidization.

Base Sequence↗
PubMed2003

Bánkúti 1201--an old Hungarian wheat variety with special storage protein composition.

Bánkúti 1201, an old Hungarian wheat variety with special quality traits, was analysed to determine the relationships between its storage protein composition and superior quality-attributes for breadmaking. Based on the storage protein composition, the variety appears to have the nature of a population, containing several genotypes with different gluten protein alleles. Using molecular markers, a new mutant x-type HMW glutenin allele was identified, containing an extra cysteine residue and showing a moderate, positive-effect on gluten properties. In lines possessing subunits Bx7+By8 the overexpression of the Bx-type subunit could be detected, resulting in a higher unextractable polymeric protein (UPP) content and increased dough strength. It was found that the presence or absence of subunit Bx7 has an equilibrating effect on the dough extensibility, which is generally characteristic of the Bánkúti 1201 population. The complex good bread-making quality of the variety, which has strong but highly extensible dough, is probably due to the balance between lines which express subunit Bx7 and those which do not.

Alleles↗
PubMed2003

Persisting TT virus (TTV) genogroup 1 variants in renal transplant recipients.

TT virus (TTV) genogroup 1 infection has an increased prevalence in solid organ transplant recipients. In this study, the presence of TTV in renal transplant recipients was examined by two PCR methods, one capable of detecting most TTV genotypes (UTR-PCR), the other specific to genogroup 1 (N22-PCR). The N22-PCR detected TTV in 57% (53/92) of the renal transplant patients and in 20% (13/66) of the healthy individuals, while the prevalence of TTV with the UTR-PCR was above 90% in both the control and the patient groups. The N22-PCR was used in longitudinal studies of 31 renal transplant recipients, these PCR products were sequenced and aligned. TTV status was not associated with the patients' age at transplantation, male to female ratio and the time lag between kidney transplantation and the TTV test. During the follow-up consistent TTV status was found in 26 patients, while two initially TTV positive patients converted to negative and three initially negative patients converted to positive. The TTV variants varied among the tested patients, but were the same in the consecutive samples of each patient, indicating that TTV infection was persistent in renal transplant recipients and novel infection occurred rarely in the post-transplant period.

Adolescent↗
PubMed2002

Codon 311 (Cys --> Ser) polymorphism of paraoxonase-2 gene is associated with apolipoprotein E4 allele in both Alzheimer's and vascular dementias.

The gene of an esterase enzyme, called paraoxonase (PON, EC.3.1.8.1.) is a member of a multigene family that comprises three related genes PON1, PON2, and PON3 with structural homology clustering on the chromosome 7.(1,2) The PON1 activity and the polymorphism of the PON1 and PON2 genes have been found to be associated with risk of cardiovascular diseases such as hypercholesterolaemia, non-insulin-dependent diabetes, coronary heart disease (CHD) and myocardial infaction.(3-8) The importance of cardiovascular risk factors in the pathomechanism of Alzheimer's disease (AD) and vascular dementia (VD)(9-13) prompted us to examine the genetic effect of PON2 gene codon 311 (Cys-->Ser; PON2*S) polymorphism and the relationship between the PON2*S allele and the other dementia risk factor, the apoE polymorphism in these dementias. The PON2*C and PON2*S allele frequencies were similar in both AD (25% and 75%) and VD groups (23% and 77%), respectively, compared with the controls (27% and 73%). The ratio of the PON2*S carriers was significantly higher among the apoE4 allele carrier AD (27%) and VD (25%) groups than in the control (12%). Our results indicate that the PON2*S and apoE4 alleles have interactive effect on the development of the two most common forms of dementias AD and VD, and further support the hypothesis that cardiovascular factors contribute to the development of AD.

Aged↗
PubMed2002

Design, pharmacokinetic, and pharmacodynamic evaluation of soft anticholinergics based on tropyl alpha-phenylcyclopentylacetate.

Four new soft anticholinergic agents based on tropyl alpha-phenylcyclopentylacetate, 15a, 15b, 18a, and 18b, were designed and synthesized. Receptor binding studies on the cloned human muscarinic receptors indicated that the new soft anticholinergic agents possessed moderate potency as pKi ranged from 6.7 to 7.6. Mydriatic studies in rabbit eyes revealed that the duration of the action of the new soft anticholinergics (8.5-11.0 h) were shorter than that of atropine (about 24 h) under pharmacodynamic equivalent dose, and one of them, 18a, showed even shorter than that of tropicamide. In addition, after unilateral administration, significant dilation of pupil in the control eyes was observed with tropicamide and atropine but not with soft drugs, suggesting the systemic activity of soft drugs was minimal. With their soft nature, the new soft anticholinergics displayed much shorter protective effect against carbachol-induced bradycardia (about 30 min) than atropine (at least 60 min) in rats. In vitro and in vivo pharmacokinetic studies demonstrated that the soft anticholinergics were rapidly hydrolyzed into the corresponding inactive metabolites once they were introduced into the systemic circulation.

Algorithms↗
PubMed2001

Effects of dopamine and dopamine-active compounds on oxytocin and vasopressin production in rat neurohypophyseal tissue cultures.

The effects of dopamine (DA) or DA-active drugs on the synthesis of neurohypophyseal (NH) hormones were studied in 13-14 day cultures of isolated NH tissue from rats. The following DA-active compounds were used (10(-6) M in each medium): DA, apomorphine (APM), Pro-Lys-Gly (PLG), butaclamol (B), haloperidol (HP), chlorpromazine (CPZ) and sulpiride (SP). The oxytocin (OT) and vasopressin (VP) contents of the condensed media were determined by RIA after a 1 or 2 h incubation. Significantly increased contents of OT and VP were detected in the tissue culture media following DA, APM or PLG administration. This elevation of NH hormone production could be blocked by previous administration of B or the DA receptor antagonists HP, CPZ or SP. The application of B after DA agonists proved ineffective. The results indicate that NH hormone production can be directly influenced by the DA-ergic system. The DA-ergic control of NH hormone secretion in rats can occur independently of the hypothalamus, at the level of the posterior pituitary.

Animals↗
PubMed2001

Prevalence and age distribution of human herpesvirus-8 specific antibodies in Hungarian blood donors.

Sera of blood donors were investigated by a peptide ELISA and indirect immunofluorescence assay to assess the prevalence of HHV-8 infection in the Hungarian population. A 14 amino acid long synthetic oligopeptide from the carboxyterminus of orf65/small virus capsid antigen was used as antigen in the ELISA. ELISA results were confirmed by recombinant orf65 antigen Western blot. Antibodies to the latent nuclear antigen were detected by the immunofluorescence assay. Nine of 12 sera obtained from patients with classical Kaposi sarcoma were reactive by ELISA whereas all were positive by immunofluorescence. Four of 482 (0.83%) healthy blood donors had anti-orf65 peptide antibodies and 17/1089 (1.56%) had antibodies to the latent nuclear antigen. In a group of children ages 1-14 years, antibodies to the latent nuclear antigen (0/29) were not detected. The prevalence of antibodies to the latent nuclear antigen showed a moderate but significant increase in correlation with senescence. In the Kaposi sarcoma patients, the titre of antibodies to the latent nuclear antigen was significantly higher than in the healthy seropositive donors. The overall HHV-8 seroprevalence by the two assays was 2.28% (11/482) in the Hungarian blood donor group.

Adolescent↗
PubMed2001

HHV-8 ELISA based on a one-step affinity capture of biotinylated K8.1 antigen.

The immunogenic envelope antigen gp35-37 of human herpesvirus-8 (HHV-8) is encoded by orfK8.1. An ELISA is described using streptavidin capture of bacterially expressed and biotinylated recombinant K8.1 antigen. The antigen capture strategy provides a simple and reliable method, which does not require high yield production and purification of the recombinant antigen before the serological assay. The specificity and sensitivity of the K8.1 ELISA were validated by gp35-37 envelope antigen Western blot and anti-lytic membrane immunofluorescence assay using lytically induced HHV-8 infected BCBL-1 cells. Under the established ELISA conditions, eight of the 10 Kaposi's sarcoma patients and five of the 180 healthy blood donors had IgG antibodies to K8.1 envelope antigen.

Biotin↗
PubMed2001

Transcriptional activity of human papillomavirus type 16 variants having deletions in the long control region.

Transcription of the E6 and E7 viral oncogenes of human papillomavirus (HPV) type 16 is regulated by the P97 major early promoter, and enhancer and silencer elements found in the long control region (LCR). In this study, we tested the transcriptional activity of natural HPV 16 variants having long deletions in the LCR. The HPV 16 LCR regions were amplified from invasive cervical cancer specimens, and cloned into the reporter vector pALuc. Transcriptional activity of the different clones was measured by luciferase test after transient transfection into HeLa cells. The deletions found in the LCR encompassed parts of the enhancer and either the YY1-specific silencer alone or together with the CDP-specific silencer. The transcriptional activity of these deletion variants were usually reduced compared with that of the corresponding full-length clones. However, a deletion variant lacking the whole enhancer and both silencer regions retained substantial enhancer activity on the P97 promoter. These results point to the existence of a novel context-dependent enhancer element in the 5' LCR of HPV 16.

DNA, Viral↗
PubMed2001

Comparative studies on [Ca2+]i-level of fibroblasts from Alzheimer patients and control individuals.

The accumulation of the beta-amyloid peptide (betaAP) in the brain, produced from the ubiquitously expressed amyloid precursor protein (APP) is a defining feature of Alzheimer's disease (AD). Consistent with studies demonstrating the importance of skin biopsy in the diagnosis of neurodegenerative disorders, we investigated whether differences in intracellular free calcium levels ([Ca2+]i) of cultured cutaneous fibroblasts derived from sporadic AD patients and from age-matched control individuals might be present. [Ca2+]i was measured in Fura-2AM-loaded human fibroblasts by dual wavelength spectrofluorimetry. AD cells exhibited lower [Ca2+]i as compared to the control cultures. Exposure of fibroblasts to betaAP resulted in increased [Ca2+]i of the control cells, but not of AD fibroblasts. Our test could prove useful in supporting the diagnosis of (sporadic) AD in patients suspected of suffering from the disease.

Aged↗