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Biomedical subjects

A Magyar

Publications and source records attributed to A Magyar.

At least 37 records · Page 2Linked to original sources
PubMed1996

Opioid binding profile of morphiceptin, Tyr-MIF-1 and dynorphin-related peptides in rat brain membranes.

Opioid properties of several morphiceptin- (Tyr-Pro-Phe-Pro-NH2), Tyr-MIF-1 (Tyr-Pro-Leu-Gly-NH2) and dynorphin-derivatives were characterized in rat brain in vitro receptor binding assay and in electrically stimulated longitudinal muscle strip preparation of guinea pig ileum. In the case of morphiceptin-related peptides, an excellent correlation was found between the [3H]-naloxone binding displacement data and the agonist potencies determined in the bioassay. The "turning point' was the C-terminal amidation in the tri- and tetrapeptide pairs in both series. Tyr-MIF-1 derivatives showed weak affinity in the opioid receptor binding assay and none of them had any remarkable effect in the bioassay either as agonist or antagonist. The dynorphin A(1-10)-peptides modified at positions 5 and 8 retained their affinity with Pro5-, Pro8-, and Ala8-substituents, whereas some loss of affinity was observed in the case of Gly8-Dyn A(1-10).

Analgesics↗
PubMed1995

Structure and tissue-specific expression of the Drosophila melanogaster organellar-type Ca(2+)-ATPase gene.

A 14 kb genomic clone covering the organellar-type Ca(2+)-ATPase gene of Drosophila melanogaster has been isolated and characterized. The sequence of a 7132 bp region extending from 1.1 kb 5' upstream of the initiation ATG codon over the polyadenylation signal at the 3' end has been determined. The gene consists of nine exons including one with an exceptional size of 2172 bp representing 72% of the protein coding region. Introns are relatively small (< 100 bp) except for the 3' intron which has a size of 2239 bp, an exceptionally large size among Drosophila introns. Five of the introns are in the same positions in Drosophila, Artemia and rabbit SERCA1 Ca(2+)-ATPase genes. There is only one organellar-type Ca(2+)-ATPase gene in the Drosophila genome, as was shown by Southern-blot analysis [Váradi, Gilmore-Hebert and Benz (1989) FEBS Lett. 258, 203-207] and by chromosomal localization [Magyar and Váradi (1990) Biochem. Biophys. Res. Commun. 173, 872-877]. Primer extension and S1-nuclease assays revealed a potential transcription initiation site 876 bp upstream of the translation initiation ATG with a TATA-box 23 bp upstream of this site. Analysis of the 5' region of the Drosophila organellar-type Ca(2+)-ATPase gene suggests the presence of potential recognition sequences of various muscle-specific transcription factors and shows a region with remarkable similarity to that in the rabbit SERCA2 gene. The tissue distribution of expression of the organellar-type Ca(2+)-ATPase gene has been studied by in situ RNA-RNA hybridization on microscopic sections. A low mRNA abundance can be detected in each tissue of adult flies, suggesting a housekeeping function for the gene. On the other hand a pronounced tissue specificity of expression has also been found as the organellar-type Ca(2+)-ATPase is expressed at a very high level in cell bodies of the central nervous system and in various muscles.

Amino Acid Sequence↗
PubMed1995

Substrate- and inhibitor-specificity of a non-endothelial enzyme which forms [Met5]-enkephalin from [Met5]-enkephalin-Arg6,Phe7 in isolated rabbit ear artery: pharmacological characterization.

The captopril-inhibited enzyme which forms [Met5]-enkephalin from [Met5]-enkephalin-Arg6,Phe7 in isolated rabbit ear artery was characterized further by using various natural substrate candidates/analogues ([Met5]-enkephalin-Arg6,Phe7 and its amide, [Met5]-enkephalin, angiotensin I and bradykinin), peptidase inhibitors such as captopril, enalaprilate and thiorphan and by endothelial removal. 10(-5) and 10(-4) M but not 10(-6) M captopril reduced the effectiveness of [Met5]-enkephalin-Arg6,Phe7 and potentiated the effect of bradykinin but did not affect markedly the action of the other peptides. Of the inhibitors, enalaprilate was less effective than captopril, and thiorphan had no effect. The [Met5]-enkephalin-Arg6,Phe7-->[Met5]-enkephalin conversion was not affected by endothelial removal. The substrate and inhibitor spectrum of this non-endothelial enzyme activity bears no relationship in other, hitherto characterized dipeptidylcarboxypeptidases/endopeptidases known to be involved in the metabolism of the tested peptides.

Amino Acid Sequence↗
PubMed1995

The surface phenotype of swine blood and tissue eosinophil granulocytes.

Cell surface antigens of swine eosinophil granulocytes were studied with flow cytometry and immunohistochemistry. The monoclonal antibody 335-2, specific for swine differentiation antigen swC1a, originally described to be present on swine T and myeloid cells, is able to distinguish swine eosinophils (swC1a negative) from neutrophils (swC1a positive). This monoclonal antibody (mAb) was used in two-colour fluorescence measurements in combination with anti-swine -CD2, -CD4, -CD8, -MHC class II, -LFA-1 or -swC3 mAbs. All of the blood eosinophils proved to be positive for LFA-1 and swC3, a common marker of swine monocytes, granulocytes and macrophages. However, they do not react with antibodies recognizing swine CD2, CD4, CD8 or MHC class II cell surface molecules. The reactivity pattern of tissue eosinophils with these mAbs was determined on cryostat sections of different tissues of swine. Tissue eosinophils were negative for swC1a, CD2, CD8, while all of them reacted with swC3. In contrast with blood eosinophils, 10-30% of tissue eosinophils were demonstrated to be negative for LFA-1. In some cases, a few tissue eosinophils were found to be stained weakly by antibodies to swine CD4 or MHC class II antigens.

Animals↗
PubMed1994

CD and Fourier transform ir spectroscopic studies of peptides. II. Detection of beta-turns in linear peptides.

Comparative CD and Fourier transform ir (FTIR) spectroscopic data on N-Boc protected linear peptides with or without the (Pro-Gly) beta-turn motif (e.g., Boc-Tyr-Pro-Gly-Phe-Leu-OH and Boc-Tyr-Gly-Pro-Phe-Leu-OH) are reported herein. The CD spectra, reflecting both backbone and aromatic contributions, were not found to be characteristic of the presence of beta-turns. In the amide I region of the FTIR spectra, analyzed by self-deconvolution and curve-fitting methods, the beta-turn band showed up between 1639 and 1633 cm-1 in trifluoroethanol (TFE) but only for models containing the (Pro-Gly) core. This band was also present in the spectra in chloroform but absent in dimethylsulfoxide. These findings, in agreement with recent ir data on cyclic models and 3(10)-helical polypeptides and proteins in D2O [see S. J. Prestrelski, D. M. Byler, and M. P. Thompson (1991), International Journal of Peptide and Protein Research, Vol. 37, pp. 508-512; H. H. Mantsch, A. Perczel, M. Hollósi, and G. D. Fasman (1992), FASEB Journal, Vol. 6, p. A341; H. H. Mantsch, A. Perczel, M. Hollósi, and G. Fasman (1992), Biopolymers, Vol. 33, pp. 201-207; S. M. Miick, G. V. Martinez, W. R. Fiori, A. P. Todd, and G. L. Millhauser (1992), Nature, Vol. 359, pp. 653-655], suggest that the amide I band, with a major contribution from the acceptor C = O of the 1<--4 intramolecular H bond of beta-turns, appears near or below 1640 cm-1, rather than above 1660 cm-1.(ABSTRACT TRUNCATED AT 250 WORDS)

Amino Acid Sequence↗
PubMed1994

Design of opioid peptides for a potential delta-receptor affinity label function: comparison with the mu-specific Tyr-D-Ala-Gly-(Me)Phe-chloromethyl ketone.

To find a delta-opioid receptor preferring peptide structure containing an Asp residue in a potentially interacting position, Tyr-Pro-Phe-Asp, Tyr-D-Ala-Phe-Asp, Tyr-D-Ala-Gly-Phe-Asp, Tyr-D-Ala-Gly-Phe-Asp alpha- and beta-methyl ester and Tyr-Gly-Gly-Phe-Asp peptides were synthesized and their biological activities were analyzed in vitro in mouse vas deferens and longitudinal muscle strip of guinea pig ileum. Changing the beta-methyl ester for an alkylating chloromethyl ketone moiety in the delta-receptor-selective agonist Tyr-D-Ala-Gly-Phe-Asp-beta-methyl ester enhanced further the delta-receptor preference. The delta-receptor selective chloromethyl ketone but not the beta-methyl ester gave a very slow washout after prolonged incubation in the mouse vas deferens bioassay; however, it was still readily displaceable by naloxone. The washout pattern of mu-specific Tyr-D-Ala-Gly-(Me)Phe chloromethyl ketone did not differ in the bioassays from that of the corresponding Gly5-ol derivative. Both chloromethyl ketones gave irreversible characteristics in the receptor binding assay.

Affinity Labels↗
PubMed1994

Postacute pancreatic pseudocysts: definition and operative treatment.

Authors survey earlier definitions of classification of pancreatitis (Symposiums in Marseilles, 1963, Cambridge, 1983, Marseilles, 1984). They define the concept of postacute pancreatic pseudocyst based on their own clinical practice, describe its clinical view and characteristic signs. They noticed in 90 cases (9%) postacute pancreatic pseudocysts during 991 pancreatic pseudocyst operations at 850 patients in 5-year period in their own practice. That postacute pseudocysts were found 6 weeks after severe acute pancreatitis in patients who were clinically in recovering state, feverless and alimented orally. The operative treatment of postacute pseudocysts was in 70% outer drainage (in 58 cases from 63 were performed necrectomy, too), in 14% (13 cases) inner drainage and in 16% resection (from 14 cases 11 distal resections, 10 times associated with splenectomy). The chosen operative treatment was significantly (p < 0.01) more outer drainage and less inner drainage. The mortality and morbidity indexes of postacute pancreatic pseudocysts did not deviate significantly from the same values of the whole patient material.

Acute Disease↗
PubMed1994

Pancreatic pseudocysts causing compression symptoms.

The authors survey the surgical treatment of duodenal or choledochal stenosis which were detected during the operation of 991 pancreatic pseudocysts in the period of 5 years, from 1987 to 1992, at 850 patients. They found that in the case of common occurrence of mechanical jaundice and pancreatic pseudocyst in 40% of cases the drainage or resection of pseudocyst was enough to ensure the free biliary passage. In case of combined operation the stenosis of choledochus was solved in 64% of cases with sphincteroplasty. In case of common occurrence of duodenal stenosis and pancreatic pseudocyst the drainage of pseudocyst was enough in 69% of cases to ensure the free gastroduodenal passage and at 31% was necessary the combined operation.

Cholestasis↗
PubMed1994

A mouse monoclonal antibody reacting with swine leukocytes: a flow cytometrical and immunohistochemical study.

A mouse monoclonal antibody (Mab) was prepared by immunization of Balb/c mice with porcine peripheral blood mononuclear cells. Its reactivity was studied by flow cytometry and immunohistochemistry. By flow cytometry 75-90% of blood lymphocytes and 93-97% of blood granulocytes showed positivity, while all monocytes were labelled. The specificity of the Mab was investigated further by immunohistochemical methods using different tissues of swine. Both cortical and medullary thymocytes strongly expressed the target antigen of Mab 335-2. Intensive staining of T cell dependent areas in the lymph nodes, spleen and tonsils was also observed. Many positive cells occurred in the red pulp of the spleen. In the non-lymphoid tissues no organ-specific staining was observed, except for the connective tissue which contained scattered positive cells. Kupffer's cells and some glial cells reacted with this Mab. These results suggest that this novel Mab recognizes a major antigen present on immature and mature T cells; however, subpopulations of myeloid cells (neutrophils, monocytes, and some types of macrophages) share this antigen.

Animals↗
PubMed1993

Kinetic parameters of antagonism by the delta opioid receptor selective peptide antagonist Boc-Tyr-Pro-Gly-Phe-Leu-Thr against selective and non-selective agonists in the mouse vas deferens.

The kinetic parameters of antagonism by the delta opioid receptor selective antagonist N-t-Boc-Tyr-Pro-Gly-Phe-Leu-Thr, obtained by using moderately selective or selective agonists, were compared in the mouse vas deferens bioassay. The apparent affinity for the preferred receptor type was 6.8 times higher when selective agonist was used, resulting in a Ke of 81.4 nM (66.3-99.9, n = 6) against [D-Ala2, D-Leu5]-enkephalin, with a 3700-fold delta over mu or kappa selectivity ratio.

Analgesics↗
PubMed1990

Molecular cloning and chromosomal localization of a sarco/endoplasmic reticulum-type Ca2(+)-ATPase of Drosophila melanogaster.

We report here the characterization of a Drosophila melanogaster cDNA that encodes a sarco/endoplasmic reticulum-type Ca2(+)-ATPase. Previously we amplified the phosphorylation site - FITC-binding site fragment of this cDNA by Polymerase Chain Reaction utilizing homology primers (Váradi, A., Gilmore-Hebert, M. and Benz, E. J. Jr. (1989) FEBS Letters 258 203-207) and in the present work we used this fragment as probe for isolation of a cDNA clone with the intire coding region. The isolated 3.3 kb clone has been sequenced and the primary structure of the encoded protein has been deduced. It consists of 1002 amino acids with all the characteristic features of the P-type ATPases. It shows 67-71% amino acid identity and an apparently identical hydropathy profile with the mammalian sarco/endoplasmic reticulum-type Ca2(+)-ATPases. On basis of sequence similarity we suggest that the first transmembrane segment of sarco/endoplasmic reticulum type Ca2(+)-ATPases may be responsible for targeting of these transport proteins into the organellar membrane. The gene of this sarco/endoplasmic reticulum-type Ca2(+)-ATPase has been mapped on the right arm of chromosome 2, in section 60A.

Amino Acid Sequence↗
PubMed1990

Stereoselective effect of warfarin and bilirubin on the binding of 5-(o-chlorophenyl)-1,3-dihydro-3-methyl-7-nitro-2H-1,4-benzodiazepin-2- one enantiomers to human serum albumin.

The binding of the title benzodiazepine enantiomers and its modulation by warfarin and bilirubin were studied by chromatography on human serum albumin (HSA) immobilized on Sepharose 4B, and also by a combination of ultrafiltration and circular dichroism (UF-CD) methods. In the absence of warfarin and bilirubin the binding of the benzodiazepine was not stereoselective. (S)-Benzodiazepine and (S)-warfarin mutually increased the binding of each other, while the binding of (R)-benzodiazepine was preferentially enhanced on HSA saturated with bilirubin.

Anti-Anxiety Agents↗
PubMed1990

Characterization of kappa 1 and kappa 2 opioid binding sites in frog (Rana esculenta) brain membrane preparation.

The distribution and properties of frog brain kappa-opioid receptor subtypes differ not only from those of the guinea pig brain, but also from that of the rat brain. In guinea pig cerebellum the kappa 1 is the dominant receptor subtype, frog brain contains mainly the kappa 2 subtype, and the distribution of the rat brain subtypes is intermediate between the two others. In competition experiments it has been established that ethylketocyclazocine and N-cyclopropylmethyl-norazidomorphine, which are nonselective kappa-ligands, have relatively high affinities to frog brain membranes. The kappa 2 ligands (Met5)enkephalin-Arg6-Phe7 and etorphine also show high affinities to the frog brain. Kappa 1 binding sites measured in the presence of 5 microM/D-Ala2-Leu5/enkephalin represent 25-30% of [3H]ethylketocyclazocine binding in frog brain membranes. The kappa 2 subtype in frog brain resembles more to the mu subtype than the delta subtype of opioid receptors, but it differs from the mu subtype in displaying low affinity toward beta-endorphin and /D-Ala2-(Me)Phe4-Gly5-ol/enkephalin (DAGO). From our data it is evident that the opioid receptor subtypes are already present in the amphibian brain but the differences among them are less pronounced than in mammalian brain.

Amino Acid Sequence↗
PubMed1989

[Total prosthesis implantation in the arthritic hip].

In 11 patients, hip arthrodeses were converted to arthroplasties. The follow-up period ranged from 1 to 21 years. In some cases the patients' own assessment contrasted with the objective findings. No difference could be determined between previously arthrodesed and ankylosed hips. The duration of arthrodesis did not have an influence on the long-term results. It is interesting to note that in this group of patients the long-term survival rate proved to be slightly better than the overall survival rate for all patients with arthroplasties performed in our clinic.

Aged↗
PubMed1987

Prenatal fate of parthenogenetic cells in mouse aggregation chimaeras.

Parthenogenetically activated BCF1 and fertilized BALB/c embryos were aggregated to form chimaeras. The fate of the parthenogenetic component was followed in the conceptus during the second half of gestation. The results indicate an early strong selection against parthenogenetic cells in the extra-embryonal part, which is presumably complete by term, and a weaker selective process in the embryo. During early development, parthenogenetic cells have nearly normal developmental potency in the embryo, which allows their balanced contribution in the chimaeras on day 12. Later, this contribution declines significantly resulting in an unbalanced relation to the advantage of the fertilized counterpart. From the results, we suggest that gametic imprinting may play a role not only in the key steps of preimplantation and early postimplantation development, but later in cell and tissue differentiation.

Age Factors↗