PubMed Health⌕ Search

Biomedical subjects

J Molnár

Publications and source records attributed to J Molnár.

At least 55 records · Page 3Linked to original sources
PubMed1998

[Diagnosis of Prader-Willi syndrome by reverse transcriptase polymerase chain reaction].

To approve Prader-Willi syndrome by molecular diagnostic assay, polymerase chain reaction of reverse-transcribed RNA was introduced by which indirect information can be gained on all known forms of the mutation. In this pilot study, 4 patients and 16 healthy control individuals were examined. Although the different mutation forms can not directly by identified by this approach, it is a useful and reliable test to confirm the clinical diagnosis of the Prader-Willi syndrome, and to screen for the syndrome in patients who present with only a few typical features.

Humans↗
PubMed1998

[Incidence of factor V G1681A (Leiden) mutation in samplings from the Hungarian population].

Thromboembolic disorders affect 0.1% of the adult population. Two main groups of the underlying predisposition factors can be identified: environmental factors (e.g. dietary habits, physical activity, surgical interventions, pregnancy etc.) and several genetic predispositions (e.g. inherited anticoagulant defects). After the discovery of the genetic mutation of factor V, called Leiden mutation, it turned out, that this mutation is responsible for the development of resistance to activated protein C in majority of the cases. The importance of the Leiden mutation is further emphasised by population based investigations, which makes it the most frequent thrombosis risk factor known today. In our study we have identified 43 heterozygotes and 3 homozygotes with Leiden mutation in total of 665 samples. The 6.47% heterozigocy is in the range of earlier reports from Europe. The homozygote/heterozygote distribution deviated from the value predicted by the Hardy-Weinberg law.

Adult↗
PubMed1998

[Mutation analysis in the CTG-base multiplication in a family with myotonic dystrophy in three generations].

A PCR-based method with a novel silver staining detection was developed for the determination of CTG repeat number in the 3' untranslated region of the MD-PK gene responsible for myotonic dystrophy. Through the investigation of a family with affected members in three generations the application of the method is presented. According to the results, healthy individuals were verified easily, and the repeat number in patients with mild features or with premutation could be determined accurately. In severe clinical forms, e.g. congenital myopathy, the expansion can be deduced only from the lack of amplification, however, this is also helpful if the segregation of familial alleles is known.

Alleles↗
PubMed1997

[Androgen receptor gene (CAG)n of spinal and bulbar muscular atrophy found in the normal child population in Hungary].

A simple and accurate molecular biology method was developed for the diagnosis of the spinal and bulbar muscular atrophy. With this method DNA isolated from peripheral blood of 40 unaffected, apparently healthy children was assayed for the CAG repeat polymorphism responsible for the disease. The results were compared with population genetic studies of international references, and the data showed no differences between the Hungarian repeat length and findings of others. Our experience shows, that this method can be used for the differential diagnosis of muscular atrophies and praenatal diagnostics in affected families.

Child↗
PubMed1997

An alternative purification protocol for producing hepatitis B virus X antigen on a preparative scale in Escherichia coli.

A truncated variant of the hepatitis B virus X gene (HBx) was cloned into the fusion expression vector of pGEX-3X (Pharmacia), resulting in a GST-HBx fusion gene construction (pGEX-3XXBF). This plasmid was transformed into and expressed by the Escherichia coli strain DH5. More than 80% of the expressed fusion protein was found in the insoluble fraction (inclusion body) of the cell lysate. The fusion protein was selectively extracted from the inclusion bodies with 8 M urea at pH 6.5, and it was refolded by diluting 3-fold with deionized distilled water at 4 degrees C. The in vitro cleavage of the refolded fusion protein by factor Xa at about 2-3 mg ml-1 in the presence of 2.66 M urea at pH 6.5 was complete. The final steps of purification involved precipitation of the cleaved proteins with ammonium sulphate, solubilization in guanidine hydrochloride and separation on a Superdex 75 FPLC column. With this approach, following an inclusion body strategy and a beneficial in vitro refolding, a predominantly hydrophobic and highly disulphide-bonded protein was produced in preparative scale for subsequent diagnostic use.

Amino Acid Sequence↗
PubMed1996

New aspects of the neuroendocrine role of PACAP.

The presence of PACAP was revealed in the anterior pituitary with RIA, HPLC, and with the demonstration of its mRNA. The level of PACAP mRNA in the anterior pituitary is the highest during the proestrous LH surge. In our immunohistochemical studies we were able to demonstrate PACAP immunoreactive cells in the anterior pituitary. The shape and the distribution of PACAP immunoreactive cells were very similar to that of the gonadotropes; however, the number of PACAP cells was less than that of LH cells. Additionally, another PACAP-positive cell population with small diameter appeared in the proestrous stage, during pregnancy and lactation. Double labeling revealed that the major part of large PACAP cells exhibited LH immunoreactivity and those with a small diameter contained PRL. It is not clear whether the pituitary- or the hypothalamic-born PACAP, or both, influence pituitary LH and PRL secretion. I.c.v. administration of PACAP just prior to the critical period in the proestrous stage inhibited the expected ovulation and blocked the proestrus LH and PRL surge, although i.v. administration of PACAP had no effect. PACAP antiserum did not interfere with ovulation when i.c.v. or i.v. injection was used. Our results support the view that PACAP has a role in the control of LH and PRL secretion during the estrous cycle, pregnancy, and lactation. The inhibitory effect of PACAP on ovulation is mediated through the hypothalamus.

Animals↗
PubMed1996

Effect of supplementation with selenium on whole blood glutathione peroxidase activities and on plasma and tissue selenium concentrations in lambs.

In recent years the selenium (Se) intake of the human population of the UK has shown a marked decline from 60 micrograms/d in 1978 to around 30 micrograms/d in 1990 owing largely to a significant reduction in the importation of North American wheat for bread-making flour. Other countries (Finland, for example) in similar situations have instituted fertilization programs in order to raise cereal Se concentrations and thus boost dietary intakes. An alternative approach would be to increase the Se concentration of carcass meat by supplementation of meat animals for a limited period prior to slaughter. A trial was set up with store lambs to evaluate this approach. Sixteen Scottish Blackface lambs were stratified according to live weight and then randomly allocated to one of four treatments: unsupplemented, or 3.5, 7, or 10.5 mg Se/head/wk. After 14 wk, the lambs were sacrificed and samples of shoulder and thigh muscle, liver, and kidney were obtained for analysis. All three treatments effected an increase in whole blood glutathione peroxidase (GSH-Px) and plasma Se concentrations over controls. Shoulder, thigh, and liver Se exhibited a dose-response relationship to treatment, but kidney Se concentrations were unaffected by treatment. Muscle and some organ meat Se concentrations can therefore be increased by supplementation and could contribute to increased human dietary intakes of the element.

Animal Feed↗
PubMed1996

PACAP participates in the regulation of the hormonal events preceeding the ovulation.

Pituitary adenylate cyclase activating polypeptide (PACAP) is a member of the secretin family. It was isolated and characterized in 1989. Its neuroendocrine role was demonstrated in vivo and in vitro systems. It seems that in vivo the effect of PACAP on the gonadotrop hormone secretion depends on the route of administration. It was reported that intravenous (i.v.) injection of PACAP elevated, while intra-cerebro-ventricular (i.c.v.) administration depressed plasma LH levels. In the present study it was demonstrated that PACAP, administered i.c.v. before the critical period of the proestrous stage, blocked the ovulation and prevented the proestrous LH surge in rats. The blocking effect of PACAP is not directly mediated by endogenous opioids because the antagonizing effect of Naloxone, an opioid receptor antagonist, was questionable. Under our experimental conditions we could not confirm the stimulating effect of i.v. administered PACAP.

Animals↗
PubMed1996

Detection of bullous pemphigoid antibodies by means of synthetic peptides as antigenic epitopes.

In an earlier study, the circulating autoantibodies in patients with bullous pemphigoid (BP) were demonstrated in higher frequencies by means of an immunoblot technique then via indirect immunofluorescence. In the present work with the help of Peptide Structure software, two matched antigenic epitopes were chosen and synthesized. The sera of 34 patients with BP were investigated in parallel by an immunoblot technique using a human epidermal extract, and by an ELISA technique with synthetic peptides. The sera of 16 healthy persons and 10 patients with other bullous diseases served as controls. Among the 34 patients with BP, 23 sera proved positive for at least one synthetic peptide. Positive reactions with the major BP antigen (230 kD) were found in 22 patients by immunoblot technique and in 16 patients by the ELISA technique with the synthetic peptide, whereas with the minor BP antigen (180 kD), positive reactions were found in 9 patients by the immunoblot technique and 18 patients by the ELISA technique using the synthetic antigenic epitope of the minor BP antigen. All control sera were negative for both antigens in ELISA investigations. In 3 patients with pemphigus vulgaris, characteristic bands against pemphigus vulgaris antigen were identified by means of the immunoblot technique, but all other cases were negative. It is suggested that the development of this technique may lead to an opportunity for the rapid and simple diagnosis of BP.

Adult↗
PubMed1995

Selenium content of convenience and fast foods in Ayrshire, Scotland.

Selenium concentrations were determined via hydride generation atomic absorption spectrometry in more than 100 convenience and fast foods including 34 vegetarian dishes. The foods were purchased mainly in Ayrshire, Scotland but some came from other parts of the UK. The results indicate a considerable amount of selenium in certain mushrooms, spinach, fish, offals and chicken-based products. The selenium content of beef- and pork-based products was generally somewhat lower. Vegetarians having a sufficient intake of mushrooms (in particular button and closed cap mushrooms) and spinach do not seem to be at risk of selenium deficiency provided of course that the selenium in mushrooms, in particular, is bioavailable.

Animals↗
PubMed1995

Immunomodulating effect of acridine tautomers on eukaryotic cells.

The immunomodulating effect of some new amino- and imino-acridine derivatives, were investigated on antibody dependent cellular cytotoxicity (ADCC) and induced-blast transformation of lymphocytes. In different concentrations (2.0 x 10(-6) M, 4.0 x 10(-8) M and 2.0 x 10(-5) M) the drugs produced a suppression of PHA and ConA induced cell proliferative response except in the case of 2b, 2d and 2g amino-acridines. The suppressive effects were dose dependent and exhibited a higher inhibitory level in the case of imino-acridines. Some drugs at low concentration exerted a little enhancing effect on ADCC reaction.

Acridines↗
PubMed1995

Interaction between tricyclic psychopharmacons and some antibiotics.

The tricyclic psychopharmacons, e.g. clozapine, promethazine and imipramine cure plasmids and inhibit plasmid transfer among bacteria due to the inhibition of supercoiling activity on DNA gyrase. In addition an interaction was found between clozapine, imipramine, promethazine and some antibiotics, e.g. penicillins and tetracycline in vitro. The nature of interaction is based on a charge transfer complex, which is formed between clozapine, imipramine, promethazine and penicillins. Differential spectrophotometry showed that ampicillin reduced the highest energy peaks of clozapine, promethazine and imipramine. Streptomycin did not alter the spectrum of clozapine; however, tetracycline somewhat reduced all the peaks of clozapine. Clozapine and promethazine exhibited a synergistic effect with ampicillin, tetracycline and gentamicin on Escherichia coli cells in in vitro. This kind of interaction was missing in the case of imipramine.

Anti-Bacterial Agents↗
PubMed1994

Staphylococcal protein A is a novel heterologous substrate for the HIV-1 protease.

Upon in vitro processing of the recombinant HIV-1/gag p24 protein, expressed in Escherichia coli as a fusion protein, by HIV-1 protease, a cleavage site within the staphylococcal protein A fusion partner was found. N-terminal sequencing of the protein A fragments showed that HIV-1 protease cleavage occurred between phenylalanine-235 and tyrosine-236 within the sequence Gln-Asn-Ala-Phe/Tyr-Glu-Ile-Leu (QNAF/YEIL) in the IgG-binding domain C of the protein A encoded by the pRIT2T fusion gene vector (Pharmacia). Results presented here have proven that the protease-sensitive site is viable in vitro on the protein A alone and other chimeric protein, protein A/beta-galactosidase. A possible significance of this phenomenon in biotechnology work is discussed.

Amino Acid Sequence↗
PubMed1994

Competition between dopamine, beta-receptor agonists and promethazine in Escherichia coli plasmid replication.

The substrates in the phenylalanine, metabolism play key roles in the physiological processes of bacteria. Promethazine affects the phenylalanine metabolism in Escherichia coli. The antibacterial and anti-plasmid actions of promethazine were prevented by phenylalanine, tyrosine, phenylpyruvic acid, phenylacetic acid, noradrenaline and dopamine in minimal medium. Isoproterenol (and phenoxybenzamine) reduced, while propranolol, oxyprenolol and alprenolol isomers enhanced the anti-plasmid effect of promethazine. Propranolol itself induced an anti-plasmid effect. The effects of beta-receptor agonists and antagonists on promethazine-induced anti-plasmid action serve as an indirect evidence of beta adrenergic like binding sites in E. coli. These binding sites are involved in the plasmid replication process and are connected with promethazine binding sites in bacteria.

Adrenergic beta-Agonists↗
PubMed1993

Expression in Escherichia coli and in vitro processing of HIV-1 p24 fusion protein.

Recombinant HIV-1 p24/p25 gag proteins were obtained from Escherichia coli using a cleavable fusion strategy. The fusion protein contains 280 amino acid residues of staphylococcal Protein A and 317 amino acid residues of p24/p25 flanking with the recognition/cleavage sequences for HIV protease. Fusion protein expressed under the control of lambda phage promoter PR was purified by IgG-Sepharose affinity chromatography. The p24/p25 part of the fusion protein was released by recombinant HIV protease in vitro. After a second IgG-Sepharose affinity chromatography, the purified p24/p25 proteins were obtained in milligram quantities. The HIV-1 p24/p25 protein displayed antigenicity similar to those of native counterparts confirmed by Western blot assays and the Abbott antigen test.

Blotting, Western↗
PubMed1993

Mechanisms of antimotility action of tricyclic compounds in Proteus vulgaris.

Tricyclic compounds were able to inhibit the motility of Proteus vulgaris. The effectiveness of antimotility action was related to the physicochemical properties of the molecules, i.e. energy of HOMO, Log P, total surface. The antimotility action of the compounds was due to their reversible inhibition on the proton pump of the bacterium. Phosphate anion antagonized the antimotility, and potassium cation enhanced the action of phosphate anion on the antimotility effect induced by the agents. Glucose reversed the antimotility action of the compounds. Factors directly increasing the bacterial proton-motive force (PMF) could change bacterial motility and the antimotility action of the tricyclic compounds.

Hydrogen-Ion Concentration↗