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Biomedical subjects

P Gergely

Publications and source records attributed to P Gergely.

At least 127 records · Page 7Linked to original sources
PubMed1988

Activation/dephosphorylation of rabbit muscle glycogen synthase by the catalytic subunits of protein phosphatase-1 and 2A.

Glycogen synthase a was purified from rabbit skeletal muscle by a procedure involving heparin-Sepharose chromatography. Glycogen synthase a was phosphorylated by the catalytic subunit of cAMP-dependent protein kinase to give synthase b1. Dephosphorylation and activation of synthase b1 was investigated using the catalytic subunits of protein phosphatase-1 and 2A. The dephosphorylation and activation of synthase b1 was biphasic with a larger rate constant for the initial phase. Analysis of tryptic phosphopeptides of glycogen synthase during the course of dephosphorylation revealed a faster initial phosphate release from site-2 by both phosphatases comparing to sites-1a and 1b. Ligand effects on synthase phosphatase reactions were also studied. Spermine was found to inhibit protein phosphatase-1 activity and to stimulate type-2A phosphatase using synthase b1 as substrate.

Animals↗
PubMed1988

Hepatoprotective and immunomodulatory effects of antioxidant therapy.

The hepatoprotective and immunomodulatory effects of silymarin and amino-imidazole-carboxamide-phosphate were studied in 40 patients with alcoholic cirrhosis of the liver in a one-month double-blind clinical trial. Treatment with either of the drugs normalized the elevated levels of aspartate aminotransferase, alanine aminotransferase and serum bilirubin, markedly reduced the high level of gamma-glutamyl transferase, increased lectin-induced lymphoblast transformation, decreased the percentage of OKT8+ cells and suppressed lymphocytotoxicity. None of these changes occurred in the placebo-treated group. Thus, the hepatoprotective effects of silymarin and amino-imidazole-carboxamide-phosphate in alcoholic cirrhosis can partly be attributed to the immunomodulatory activity of the drugs.

Adult↗
PubMed1988

Immunological effects of captopril.

The effect of captopril treatment on natural killer activity and mitogen-induced lymphocyte blastogenesis was studied in man. No significant change in immune reactivity was found either in short term (one hour after ingestion of 25 mg) or long term (after two weeks, 50 mg daily) treatment.

Captopril↗
PubMed1988

Effect of vitamin A treatment on immune reactivity and lipid peroxidation in patients with Sjögren's syndrome.

Patients with Sjögren's syndrome were treated with vitamin A (100,000 U) daily during a two-week period. The vitamin treatment significantly elevated their ADCC and NK activity. The lymphocyte blast transformation, however was not noticeably changed. After the treatment, the retinyl-ester and retinol level of the plasma significantly increased as did the plasma level of vitamin E. The level of TBA reactive substances (malondialdehyde) in the plasma increased, whilst the glutathione peroxidase and catalase activity of erythrocytes decreased. The activity of the plasma glutathione peroxidase increased, but not significantly.

Antibody-Dependent Cell Cytotoxicity↗
PubMed1988

Demonstration of leukocyte-immobilizing activity in normal human plasma.

The effect of normal human plasma on random migration of polymorphonuclear leukocytes (PMNs) in agarose micro-droplet assay was studied. Plasma, even at a concentration as low as 1%, inhibits leukocyte motility and this immobilizing activity seems to be related to a specific factor which present in human sera and is stable at 56 degrees C for 30 min. The immobilizing effect of heat-inactivated sera was abolished in vitro by indomethacin at a concentration of 0.1 micrograms/ml and it was significantly decreased by anti PGE2 antibody. Spontaneous migration of leukocytes failed to be enhanced by indomethacin (0.1 microgram/ml) alone. Anti-PGE2 alone moderately enhanced PMN motility. Immobilizing activity in human sera decreased 2 hours after indomethacin administration (Indomethacinum CHINOIN, 50 mg orally). No direct enhancing effect of indomethacin on leukocyte motility was shown in vivo. The data indicate a leukocyte-immobilizing activity of human sera. This effect is mediated by prostaglandin production induced by serum factor(s). The factor(s) responsible for the above activity may have a role in regulating leukocyte distribution and motility in vivo.

Cell Movement↗
PubMed1988

Correlation between the levels of antinuclear antibodies, anti-DNA antibodies, and complement in systemic lupus erythematosus.

Antinuclear antibody (ANA) titres, anti-native DNA levels, serum haemolytic complement (CH50), and complement components C3 and C4 were determined in 550 serum samples taken from patients with active (311 samples) or inactive (239) systemic lupus erythematosus (SLE). Increased anti-DNA levels were shown in 82% of the samples from patients with active and in 57.8% of those from inactive, disease. Decreased levels of CH50, and C3, C4 were found in 37, 50, and 80% of the samples taken from active and in 22, 29, and 67% of those from inactive, disease, respectively. Positive ANA test was found in 94.7% of the patients with active and 87.9% of those with inactive, disease. Significant differences were found between the two groups for all parameters. The correlations were close between the values of anti-DNA antibodies and CH50, as well as between the levels of CH50 and C3. Relationship between anti-DNA antibodies and C3 levels, as well as between CH50 and C4 levels was also demonstrated. Six subgroups for expressing the positivity of five parameters, 32 patterns of positive parameters were found and their possible application were suggested. In combining these parameters and using appropriate patterns, their determination may be helpful not only for the diagnosis but also for the assessment of disease activity.

Antibodies, Antinuclear↗
PubMed1987

Purification of the catalytic subunit of protein phosphatase-1 from Drosophila melanogaster.

The catalytic subunit of phosphatase-1 has been purified from Drosophila melanogaster by precipitation with (NH4)2SO4 and ethanol, by affinity chromatography on heparin-Sepharose and by fast protein liquid chromatography on Mono Q beads. The preparation is homogeneous as tested by SDS gel electrophoresis and has a molecular mass of 33,000. The phosphatase specifically dephosphorylates the beta subunit of phosphorylase kinase. Its phosphorylase phosphatase activity is inhibited by inhibitor-1, inhibitor-2, protamine and histone H2B while is stimulated by histone H1.

Animals↗
PubMed1987

Effect of (+)cyanidanol-3 on cellular immune reactions and on superoxide dismutase activity in vitro.

Immunological and antioxidant effects of the widely used hepatoprotective agent (+)cyanidanol-3 were studied in a complex in vitro test system using isolated peripheral blood lymphocytes of patients with chronic alcoholic liver disease and of healthy donors. In both groups in vitro treatment with (+)cyanidanol-3 inhibited lectin-induced lymphocyte blast transformation and chemiluminescence in a dose-dependent fashion and increased the superoxide dismutase-expression of lymphocytes without influencing the percentage of T and active T cells and antibody-dependent and spontaneous lymphocytotoxicity. The originally lower Con A-induced T cell mediated lymphocytotoxicity of patients was completely abolished, while no significant effect was seen using healthy donors' lymphocytes. (+)cyanidanol-3 markedly decreased the Con A-induced suppressor activity of patients' lymphocytes, without influencing that of normal cells. These results suggest that both antioxidant and immunomodulatory effects play an important role in the mechanism of action of (+)cyanidanol-3.

Adult↗
PubMed1987

Autophosphorylation of phosphorylase kinase and its regulatory function in the dephosphorylation of phosphorylase A.

Autophosphorylation of phosphorylase kinase was measured under conditions that favoured autoactivation. Heparin and troponin C stimulated the autophosphorylation of phosphorylase kinase at pH 6.8 in a Ca2+-dependent manner. The concentration required for the half-maximal stimulation of autophosphorylation for calcium ions was 2 microM in the absence of effectors, whereas 0.7 microM and 0.1 microM in the presence of troponin C and heparin, respectively. Calmodulin increased the rate of autophosphorylation of the alpha subunit only, resulting in a slight increase in the rate of autoactivation of phosphorylase kinase. Troponin C, heparin and polybrene enhanced the rate of autophosphorylation of both alpha and beta subunits. The increased autophosphorylation coincided with an enhancement of kinase activity. Neither of these stimulatory macromolecules had significant influence on the total number of phosphate groups incorporated into the alpha or beta subunits by autophosphorylation. Thio-autophosphorylated form of phosphorylase kinase behaved as an inhibitor in the dephosphorylation of phosphorylase a by the catalytic subunits of phosphatase-1 or phosphatase-2A and by the latent form of phosphatase-2A. Concentration of phosphorylase kinase needed to 50% inhibition was in the range of 0.05-0.08 microM.

Calmodulin↗
PubMed1987

Insoluble glycogen and its interaction with phosphorylase. A novel method for the purification of liver phosphorylase A.

Purified liver glycogen dissolved in Tris-HCl buffer (pH 6.8) was converted into an insoluble polymer by incubation with phosphorylase and glucose 1-phosphate. Elongation of the outer chains of glycogen did not alter the average molecular weight significantly as judged by sedimentation velocity measurements, but the spectrophotometric analysis of glycogen-iodine complexes showed marked differences. Insoluble glycogen could bind rabbit skeletal muscle and liver phosphorylases. The association of insoluble glycogen with phosphorylase could be treated as a distribution equilibrium between glycogen-bound and unbound phosphorylase. Based on the formation of an insoluble glycogen protein complex sedimentable even by low-speed centrifugation, a novel method has been developed for the purification of liver phosphorylase a in a homogeneous form.

Animals↗
PubMed1987

Short-term stimulation of lymphocyte proliferation by indomethacin in vitro and in vivo.

The effect of short-term (up to 24 h) in vitro and in vivo treatment with indomethacin was studied on the blastogenesis of mouse spleen cells. Indomethacin in itself induced a strong proliferation of the lymphocytes starting after 6 h treatment both in vitro and in vivo. Besides, significantly enhanced the blastogenesis of splenocytes in response to various doses of PHA and Con A. The stimulation of lectin-induced lymphocyte proliferation occurred after indomethacin treatment both in vitro and in vivo. Indomethacin had no major effect on the distribution of Lyt-1+ and Lyt-2+ subsets within the spleen cell population. An important role of the prostaglandins in the early phase of lymphocyte activation is suggested.

Animals↗
PubMed1986

Hormonal regulation of phosphorylase phosphatase activity in rat liver.

The effect of glucagon and insulin on rat liver phosphorylase phosphatase activity in vivo was investigated. The activity of phosphatase was found to decrease following the administration of glucagon and increase with insulin in a reversible manner. No change was detected in the activity of heat-stable phosphatase inhibitors in the hormone-treated samples. Liver protein kinases (regulatory subunit of cAMP-dependent protein kinase and/or Ca2+-dependent phosphorylase kinase) are suggested to regulate the activity of hepatic phosphorylase phosphatase (type 1 and 2A).

Animals↗