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Biomedical subjects

L Nagy

Publications and source records attributed to L Nagy.

At least 109 records · Page 6Linked to original sources
PubMed1995

[Role of a mediator in the prevention of malpractice suits].

The authors suggest to inaugurate a new prevention proceeding suitable for the quick ending of the more and more often conducted litigated issues between patients and physicians (health care providers), by framing the mediator system. They outline the organisation, authority, and the personal conditions of being appointed to mediator. They emphasize the difference between the board of arbitration and the mediator system.

Health Personnel↗
PubMed1995

Comparison of 5-hydroxyindole-acetic acid and para-amino hippurate clearances in newborn rabbits.

Recent study indicates that endogenous 5-hydroxyindole-acetic acid (5-HIAA) clearance can be used as an alternative procedure to para-amino hippurate (PAH) clearance for the estimation of renal plasma flow in human patients. In view of the limitations of PAH clearance measurements in newborn infants we made an attempt to validate the technique of measuring renal blood flow with 5-HIAA quantitatively against PAH clearance. Thirty-four simultaneous determinations of PAH and 5-HIAA clearances were performed in 14 newborn rabbits. 5-HIAA concentrations in plasma and urine were measured by using HPLC coupled with electrochemical detection (Beckman). Renal blood flow was found to range between 0.60 and 6.90 ml/min/kg (mean: 3.39 ml/min/kg) for 5-HIAA and from 0.93 to 6.61 ml/min/kg (mean: 3.68 ml/min/kg) for PAH clearances. There was a significant positive correlation between the values obtained by the two techniques (r = 0.84, P < 0.001). When 5-HIAA clearance was analyzed as a function of plasma 5-HIAA level only a weak, but statistically significant correlation could be detected (r = 0.33, P < 0.05). Plasma 5-HIAA measurement alone, therefore, does not reflect renal blood flow in newborn rabbits. It is concluded that endogenous 5-HIAA clearance might serve as a reliable estimate of renal blood flow in the neonate under different physiologic and pathologic conditions.

Animals↗
PubMed1995

Comparison of the effects of amino acid substitutions and beta-N- vs. alpha-O-glycosylation on the T-cell stimulatory activity and conformation of an epitope on the rabies virus glycoprotein.

The first potential N-glycosylation site of the rabies virus glycoprotein, the antigen that carries epitopes for glycoprotein-specific T-cells and virus neutralizing antibodies, is glycosylated inefficiently. Recently, we showed that addition of a beta-N-acetyl-glucosamine moiety to the asparagine residue in the corresponding synthetic fragment V V E D E G C T N L S G F (amino acids 29-41), significantly diminished the T-cell stimulatory activity and reduced the characteristic alpha-helicity of the peptide. The amino acid sequence of the glycoprotein in this region exhibits some degree of variability among different rabies virus and rabies virus related strains, including the replacement of the asparagine residue with aspartic acid or threonine. In the current study, stimulation of a specific T-cell clone by various viral strains and appropriate tridecapeptide sequences and their analogs was investigated. The T-cell recognition pattern of the rabies and rabies-related viruses was identical to that of the synthetic peptides representing the respective epitope sequences. While the asparagine could be replaced without complete loss of T-cell stimulatory activity, amino acid modifications at the C-terminus of the peptide were not tolerated. In contrast to glycosylation of the asparagine, coupling of an N-acetyl-galactosamine moiety at the serine, or galactosyl-N-acetyl-galactosamine moieties at the threonines preceding or replacing the asparagine (all O-linked sugars in the natural alpha-anomeric configuration) resulted in epitopes that lowered rather than abolished the T-cell stimulatory activity. All non-glycosylated peptides assumed a low-to-medium helicity in trifluoroethanol. O-glycosylation was more efficient than N-glycosylation in breaking the helical conformation of the peptides to result in the formation of reverse-turns or unordered structure.

Amino Acid Sequence↗
PubMed1995

Activation of retinoid X receptors induces apoptosis in HL-60 cell lines.

Retinoids induce myeloblastic leukemia (HL-60) cells to differentiate into granulocytes, which subsequently die by apoptosis. Retinoid action is mediated through at least two classes of nuclear receptors: retinoic acid receptors, which bind both all-trans retinoic acid and 9-cis retinoic acid, and retinoid X receptors, which bind only 9-cis retinoic acid. Using receptor-selective synthetic retinoids and HL-60 cell sublines with different retinoid responsiveness, we have investigated the contribution that each class of receptors makes to the processes of cellular differentiation and death. Our results demonstrate that ligand activation of retinoic acid receptors is sufficient to induce differentiation, whereas ligand activation of retinoid X receptors is essential for the induction of apoptosis in HL-60 cell lines.

Apoptosis↗
PubMed1994

Evolution of homeotic gene regulation and function in flies and butterflies.

It has been proposed that the evolution of homeotic genes parallels, and to some degree directs, the evolution of segment diversity in the myriapod-insect lineage. But the discovery of discrete Antennapedia complex (ANT-C) and bithorax complex (BX-C) gene members in crustacea, chelicerates, annelids and various insects, as well as in vertebrates, indicates that the expansion and diversification of homeotic genes preceded the diversification of arthropods and insects. How, then, have these genes influenced the evolution of body plans? To address this question, we now examine homeotic gene expression and regulation in butterflies (Lepidoptera), which, unlike flies, possess larval abdominal limbs and two pairs of wings. We show that the difference in larval limb number between these insects results from striking changes in BX-C gene regulation in the butterfly abdomen, and we deduce that the wing-patterning genes regulated by Ultrabithorax have diverged in the course of butterfly and fly evolution. These findings have general implications for the role of homeotic genes in animal evolution.

Amino Acid Sequence↗
PubMed1994

Glycosylation of synthetic T helper cell epitopic peptides influences their antigenic potency and conformation in a sugar location-specific manner.

The immunodominant T helper cell epitopes 31D and VF13N of rabies virus nucleoprotein and glycoprotein, respectively, correspond to peptide sequences AVYTRIMMNGGRLKR and VVEDEGCTNLSGF, and are expressed between amino acids 404-418 and 29-41, of the appropriate proteins. We investigated how internal or external glycosylation affects the biological activity and conformation of the peptides 31D and VF13N. Mid-chain incorporation of maltobiose or N-acetylglucosamine moieties into the asparagine residues greatly diminished the T-cell stimulatory activity in vitro (due to the diminished ability of the glycopeptides to bind to major histocompatibility complex determinants) and reduced the characteristic alpha-helicity of the peptides in aqueous trifluoroethanol solutions. In contrast, addition of maltobiose- or N-acetylglucosamine-coupled asparagines to the N-termini of peptides 31D and VF13N resulted in unchanged T-cell activity. Furthermore, N-terminal glycosylation of peptide 31D, as indicated by the functional assay, decreased the sensitivity of the peptide to degradation in human serum and did not affect the alpha-helical conformation. These data indicate that glycosylation of T-cell epitopes is not a preferable method for the preparation of antagonists, but incorporation of the sugars to appropriate positions may be advantageous in the design of T-cell agonists and peptide-based vaccines.

Amino Acid Sequence↗
PubMed1994

The role of the Distal-less gene in the development and evolution of insect limbs.

BACKGROUND: Arthropod diversity is apparent in the variations in limb number, type, and position along the body axis. Among the insects, for example, butterflies and moths (Lepidoptera) develop larval abdominal and caudal appendages ('prolegs'), whereas flies (Diptera) do not. Comparative studies of the expression and regulation during development of limb-patterning genes, such as Distal-less (Dll), may provide insights into arthropod evolution. RESULTS: We report the cloning of a Dll homolog from the butterfly Precis coenia, and present data showing that it is expressed in all developing limbs (except the mandible), including the prolegs; the relationship between Dll and wingless expression observed in Drosophila is conserved in Precis among all limbs. However, Dll is deployed in distinct spatial and temporal patterns within each limb type. CONCLUSIONS: These data suggest that Dll function, suppressed in the abdomen early in insect evolution, has been derepressed in Lepidoptera, and also suggest that there is a common mechanism underlying the formation of all insect appendages. The limb-type-specific patterns of Dll expression (and its exclusion from the mandible) indicate that regulation of Dll expression may be critical to limb morphology, and are inconsistent with Dll functioning in a simple distal-to-proximal concentration gradient.

Amino Acid Sequence↗
PubMed1994

[Testing the acid-binding capacity of Tisacid suspension and tablets by intragastric pH determination in patients with hyperacidity].

The effect of a Hungarian Al-Mg-containing drug, called Tisacid was studied using of 2.0, 1.0 and 0.5 gram doses. Two administration forms, suspension and tablet were compared. Ten informed, adult hyperacid volunteers were included into the program and three times 5-hour intragastric pH-metry was carried out in a randomized, self-controlled open clinical study (Control, after administration of tablet or suspension). Both forms were found effective in gastric acid reduction at doses of 2.0 and 1.0 g. Tisacid suspension revealed a more pronounced efficacy at the dose of 2.0 g in comparison to the same dose of tablet form. The 0.5 g dose seemed insufficient in reduction of gastric acidity in hyperacid patients applied in tablet or suspension forms. The authors emphasize the role of continuous intragastric pH-metry in clinical practice and investigation of antacids and antisecretory drugs.

Adult↗
PubMed1994

Morphogenesis in the early embryo of the lepidopteran Bombyx mori.

The regional patterns of nuclear and cell division and the changes in size and shape of the developing Bombyx mori embryo were monitored from just prior to blastoderm formation until the onset of gastrulation. Nuclear invasion of the periphery and subsequent cellularization occurs with a marked anterior to posterior gradient. Consequently, there is no syncytial blastoderm stage in which all nuclei simultaneously rest at the periphery. In addition, the posterior-most blastoderm cells do not form pole cells. Prior to gastrulation, the Bombyx blastoderm cells undergo several unusual types of cell behaviors, indicated in part by the modifications and specializations of their lateral edges. Subsequent to the completion of cellularization, localized regions of mitosis can be found within the germ anlage, but at the stage monitored, just prior to the onset of gastrulation, these regions do not appear to be the equivalent of the Drosophila mitotic domains. The implications of these findings for modeling how segmental fates are established in insects are discussed. This work confirms and extends the work of earlier histological investigations of Bombyx development.

Animals↗
PubMed1994

Identification of subcellular targets and sensitive tests of ethanol-induced damage in isolated rat gastric mucosal cells.

BACKGROUND/AIMS: The mechanisms of chemically induced injury are poorly understood. The purpose of this study was to develop a rapid method for isolation of gastric mucosal cells (GMCs) and sensitive tests for investigating cell damage and protection. METHODS: GMCs were prepared from rat glandular stomach with pronase and ethylene glycol-bis(beta-aminoethyl ether)-N,N,N',N'-tetraacetic acid (EGTA) and kept in albumin-containing, albumin-free, or Hank's solutions. Initial cell viability and responsiveness were tested with trypan blue exclusion, and stimulation or inhibition of pepsinogen secretion were tested with carbachol, 16,16-dimethyl prostaglandin E2, or carbachol plus atropine. Plasma membrane damage was assessed by trypan blue exclusion, lactate dehydrogenase or cell protein leakage, mitochondrial integrity by succinic dehydrogenase activity, and nuclear lesions by ethidium bromide DNA fluorescence. RESULTS: Incubation of GMC with ethanol resulted in 50% lethal dose for ethanol values of 12.3%, 7.4%, and 10.9% by trypan blue exclusion; 10.1%, 9.4%, and 9.1% by lactate dehydrogenase leakage; 12.8%, 10.0%, and 10.4% by succinic dehydrogenase; and 14.1%, 13.0%, and 11.5% by ethidium bromide DNA by binding using albumin-containing, albumin-free, and Hank's solutions, respectively. CONCLUSIONS: Rat GMC with high and long viability can be isolated by low concentrations of pronase and EGTA. The adapted biochemical and microscopic methods are suitable for parallel examination of chemical injury of plasma membrane, mitochondria, and nuclei. Albumin increased ethanol 50% effective concentration to GMC. A combination of biochemical and morphological methods with ethanol-induced injury to GMC is proposed for direct cytoprotection investigations.

Animals↗
PubMed1994

Gastrointestinal hemorrhage caused by secondary aorto-duodenal fistula: report of 5 cases.

Aorto-intestinal fistula is a late complication of reconstructive vascular operation, which is difficult to indentify. After the cessation of a massive, life-threatening bleeding, the best result can be expected from extraanatomical, axillobifemoral bypass. The authors treated 5 patients for fistula, developed following an aorto-bifemoral bypass. Diagnosis could be made before operation only in two of the cases. Axillo-bifemoral bypass was performed in 3 patients following the treatment of the fistula and the removal of the graft; 2 of their patients recovered.

Aged↗
PubMed1993

[The role of conservative surgery in Crohn disease: practical results obtained from a case].

The 42 years old male patient in a 12 year period got over seven laparotomies and repeated bowel resections, due to which there was left only about 50 cm long jejunum, grossly dilatated and connected side to side to the transverse colon after a right hemicolectomy. The patients was admitted in a serious state of malnutrition due to a Y-shaped fistula formation between the too long blind end of the jejunotransversostomy and the first part of the jejunum. The blind end was resected and the 2 holes on the jejunum was closed by one layer wire stitches. The histology demonstrated a typical granulomatosis process. In summary: the Crohn's disease cannot be cured by surgical means. In this panalimentary process the repeated small bowel resections imply a later short bowel syndrome. On the base of the literature and of their modest experience the authors emphasize the need of conservative surgery and for the so called skip-lesions only stricture plasties to be performed instead of resections.

Adult↗
PubMed1993

[Allergic inflammatory markers in upper respiratory allergies].

The inflammatory mediators of allergy were investigated in symptomatic patients suffering from upper respiratory tract allergy. The serum tryptase level as an indicator of mast cell activation and serum eosinophil cationic protein level as an indicator of eosinophil activation were measured. They did not find any alteration in the serum level of tryptase. The level of eosinophil cationic protein significantly increased in symptomatic patients comparing to normal healthy controls. There was not any correlation to the severity of symptoms and to the absolute eosinophil count in the peripheral blood. The different activation possibilities of the eosinophil granulocytes are discussed, highlighting the role of Th2-helper lymphocytes.

Adult↗
PubMed1993

Further characterization of the psbH locus of Synechocystis sp. PCC 6803: inactivation of psbH impairs QA to QB electron transport in photosystem 2.

The psbH gene encodes a small protein which copurifies with photosystem 2. In the cyanobacterium Synechocystis sp. PCC 6803, psbH is located upstream of the cytochrome b6-f complex genes petC and petA. In striking contrast, in the genomes of plant chloroplasts, psbH is cotranscribed with petB and petD, encoding the other two major subunits of the cytochrome b6-f complex. We report that in Synechocystis sp. PCC 6803 monocistronic psbH and dicistronic petCA transcripts are probably initiated separately, each from DNA regions bearing some similarity to Escherichia coli sigma 70 promoters. Synechocystis sp. PCC 6803 psbH null mutants were generated by cartridge mutagenesis. Studies using a rapid screening procedure involving in situ complementation showed that the PsbH protein is not absolutely required for the assembly of a functionally active photosystem 2 complex since psbH insertion and deletion strains were able to grow photoautotrophically. The rate of photoautotrophic growth was, however, slower than the wild type, and studies of oxygen evolution, chlorophyll fluorescence, and thermoluminescence indicated that this reduction in growth rate is probably due mainly to an impairment in electron flow from QA to QB. We conclude, therefore, that the PsbH protein is not an absolute requirement for photosystem 2 activity but that it functions to optimize electron flow between the two secondary plastoquinone acceptors by interacting with the QB site on the D1 protein.

Base Sequence↗