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Biomedical subjects

P Gergely

Publications and source records attributed to P Gergely.

At least 109 records · Page 6Linked to original sources
PubMed1989

Purification and partial characterization of protein phosphatases from rat thymus.

Protein phosphatases assayed with phosphorylase alpha are present in the soluble and particulate fractions of rat thymocytes. Phosphorylase phosphatase activity in the cytosol fraction was resolved by heparin-Sepharose chromatography into type-1 and type-2A enzymes. Similarities between thymocyte and muscle or liver protein phosphatase-1 included preferential dephosphorylation of the beta subunit of phosphorylase kinase, inhibition by inhibitor-2 and retention by heparin-Sepharose. Similarities between thymocyte and muscle or liver protein phosphatase-2A included specificity for the alpha subunit of phosphorylase kinase, insensitivity to the action of inhibitor-2, lack of retention by heparin-Sepharose and stimulation by polycationic macromolecules such as polybrene, protamine and histone H1. Protein phosphatase-1 from the cytosol fraction of thymocytes had an apparent molecular mass of 120 kDa as determined by gel filtration. The phosphatase-2A separated from the cytosol of thymocytes may correspond to phosphatase-2A0, since it was completely inactive (latent) in the absence of polycation and had activity only in the presence of polycations. The apparent molecular mass of phosphatase-2A0 from thymocytes was 240 kDa as determined by gel filtration. The catalytic subunit of thymocyte type-1 protein phosphatase was purified with heparin-Sepharose chromatography followed by gel filtration and fast protein liquid chromatography on Mono Q column. The purified type-1 catalytic subunit exhibited a specific activity of 8.2 U/mg and consisted of a single protein of 35 kDa as judged by SDS-gel electrophoresis. The catalytic subunit of type-2A phosphatase from thymocytes appearing in the heparin-Sepharose flow-through fraction was further purified on protamine-Sepharose, followed by gel filtration. The specific activity of the type-2A catalytic subunit was 2.1 U/mg and consisted of a major protein of 34.5 kDa, as revealed by SDS-gel electrophoresis.

Animals↗
PubMed1989

Simultaneous presence of platelet activating factor, leukotriene B4, prostaglandin F1 alpha and F2 alpha in the supernatant of human neutrophils treated with phospholipase A2 of human monocytes.

The simultaneous presence of platelet-activating factor, leukotriene B4, prostaglandin F1 alpha and F2 alpha are detectable in the supernatant of human neutrophil granulocytes treated with phospholipase A2 of human monocytes. This enzyme is suspected to play an important role in the pathomechanism of inflammation.

Dinoprost↗
PubMed1989

The role of autophosphorylation of cAMP-dependent protein kinase II in the inhibition of protein phosphatase-1.

1. The inhibition of the catalytic subunit of protein phosphatase-1 (PP-1c) by the regulatory subunit of cAMP-dependent protein kinase II (RII) was studied. 2. Phosphorylation or thiophosphorylation of RII increased its inhibitory potency up to 4- and 6-fold and rendered it competitive with respect to the substrate of PP-1c, phosphorylase a. The Ki values for thiophospho-RII and phospho-RII were 200 and 500 nM, respectively. 3. Though PP-1c was able to release phosphate from phospho-RII, its activity once incubated with phospho-RII, remained inhibited even 80% of the phosphate was released from phospho-RII. 4. The catalytic subunit of cAMP-dependent protein kinase was effective in suspending the inhibition employed either before or after the addition of phospho-RII to PP-1c. 5. No exclusive bindings of thiophospho-RII and heat-stable protein inhibitors to the PP-1c could be proved by double inhibition studies, however some synergism was observed in their effect.

Binding Sites↗
PubMed1989

Activation/dephosphorylation of muscle glycogen synthase phosphorylated by phosphorylase kinase.

1. Glycogen synthase from rabbit skeletal muscle was phosphorylated by phosphorylase kinase to yield synthase b2. 2. Dephosphorylation and activation of synthase b2 by the catalytic subunits of protein phosphatase-1 (PP-1c) and protein phosphatase-2A (PP-2Ac) was studied. The apparent Km of PP-1c and PP-2Ac were 3.3 microM and 6.2 microM, respectively. The apparent Vmax of PP-1c was about two times larger than that of PP-2Ac. 3. Ligands with phosphate moiety (AMP, glucose-6-P at high concentration) caused an inhibition in dephosphorylation by both phosphatases. Spermine inhibited the dephosphorylation by PP-1c and stimulated the action of PP-2Ac. Therefore it can be employed to distinguish the phosphatases using synthase b2 as substrate.

Animals↗
PubMed1989

Cyclic AMP level of lymphocytes in patients with systemic lupus erythematosus and its relation to disease activity.

The basal and stimulated intracellular cyclic AMP (cAMP) levels of peripheral blood mononuclear cells (PBMC) of 16 control subjects and 14 patients with systemic lupus erythematosus (SLE), all fulfilling the ARA criteria, were studied. No significant difference in basal cAMP level was observed between SLE patients and controls. SLE lymphocytes (both active and inactive) elicited a diminished response to aminophylline and prostaglandin E2 (PGE2). No correlation was seen between disease activity and either baseline cAMP levels or response to these stimulators. We suggest an intrinsic (not disease activity-related) impairment of the adenylate cyclase-dependent regulatory mechanism in the PBMC of SLE patients, which may result in a defective IL-2 production and IL-2 dependent biological functions.

Aminophylline↗
PubMed1989

Depressed monocyte production of interleukin-1 and tumor necrosis factor-alpha in patients with alcoholic liver cirrhosis.

Interleukin-1 and tumor necrosis factor-alpha activity by E. coli lipopolysaccharide-triggered monocytes were studied in patients with chronic alcoholic liver disease. Monocytes from cirrhotic patients were shown to have a significant reduction in IL-1 and TNF-a activity, compared with that from age- and sex-matched healthy controls. These findings indicate further immunoregulatory disturbances concerning alcoholic liver cirrhosis.

Adult↗
PubMed1989

Effect of lentinan on superoxide dismutase enzyme activity in vitro.

The effects of lentinan on enzyme induced lipid peroxidation, xanthine-xanthine oxidase-induced cytochrome c reduction, and on the superoxide-dismutase (SOD) enzyme activity and expression of human lymphocytes and erythrtocytes were studied. Lentinan in low concentration decreased SOD activity of lymphocytes and erythrocytes from healthy subjects. In higher concentration (10 micrograms/ml) lentinan increased the pathologically low SOD activity of erythrocytes and lymphocytes of patients with cirrhosis of the liver. No significant antioxidant (free radical scavenger) effect has been observed in NADPH-induced and Fe3+-stimulated lipid peroxidation and in xanthine-xanthine oxidase system.

Animals↗
PubMed1989

A simple assay for tumor necrosis factor using HEp-2 target cells.

We developed a sensitive bioassay system for the determination of tumor necrosis factor-alpha (TNF) using HEp-2 adherent human epipharynx carcinoma cells as targets. TNF from separated human monocytes was triggered by lipopolysaccharide (LPS). In a 24 hr 3H-thymidine incorporation assay, TNF-like activity was seen to reproducibly destroy radiolabeled target cells, i.e., inhibits thymidine incorporation and causes detachment of adherent HEp-2 cells. HEp-2 cells were insensitive to human interleukin-1 (IL-1) and interleukin-2 (IL-2). In contrast, human interferon-alpha and gamma were also cytotoxic for target cells. Monocyte supernatants stimulated by LPS, however, failed to contain detectable amounts of interferons.

Biological Assay↗
PubMed1989

Detection and mapping of polymorphic KpnI alleles in the human T-cell receptor constant beta-2 locus.

Southern blot analysis with human T-cell receptor (TcR) beta-chain specific cDNA probes revealed two novel allelic forms of the TcR beta-2 gene locus. Three different genotypes were noted based on the presence of polymorphic KpnI restriction fragments: I, 5.7 kb fragment only; II, 3.9 kb and 1.8 kb fragments only; III, all three polymorphic fragments. This hybridization pattern suggested that the presence or absence of a polymorphic KpnI site within the 5.7 kb fragment defines the two different allelic forms of the TcR beta chain locus. By Southern blot analysis of genomic DNA from T-cell lines with deleted C-beta-1 regions and computer-assisted restriction site mapping of germline and cDNA sequences of the C-beta-2 locus, the polymorphic KpnI site was localized at 24 bp 5' to the third exon of the C-beta-2 gene. It was determined that the polymorphic KpnI site and the earlier described polymorphic BglII site located 5' to the C-beta-2 gene are not co-inherited. No difference was noted in distribution of the KpnI genotypes and allelic frequencies between 26 normal individuals and 22 patients with systemic lupus erythematosus. However, this newly characterized polymorphism of the TcR locus should provide a useful tool to analyse the role of inherited genetic variations in the function of T lymphocytes under normal and pathological conditions.

Alleles↗
PubMed1989

Defective production of interleukin-1 and tumour necrosis factor-alpha by stimulated monocytes from patients with systemic lupus erythematosus.

Interleukin-1 and tumour necrosis factor-alpha activity by E. coli lipopolysaccharide-triggered monocytes was studied in patients with systemic lupus erythematosus in various stages of activity. Monocytes from both groups of SLE patients produced significantly less tumour necrosis factor-alpha activity than those of age and sex matched healthy controls. However, interleukin-1 activity was only significantly reduced in patients with active stage of the disease. These findings indicate further immunoregulatory disturbances in monocyte function concerning SLE.

Adult↗
PubMed1989

Studies on the monocyte interleukin-1 and tumour necrosis factor-alpha production in patients with alcoholic liver cirrhosis.

Interleukin-1 and tumour necrosis factor-alpha activities by E. coli lipopolysaccharide-triggered monocytes were studied in patients with chronic alcoholic liver disease. Monocytes from cirrhotic patients were shown to have significantly reduced IL-1 and TNF-a activities, compared with that from age and sex matched healthy controls. These findings indicate further immunoregulatory disturbances concerning alcoholic liver cirrhosis.

Adult↗
PubMed1989

Cathepsin D-like activity in serum of patients with systemic lupus erythematosus.

Cathepsin D-like activity was measured in the sera of 62 patients with active systemic lupus erythematosus (SLE), 9 patients with progressive systemic sclerosis, 9 patients with chronic glomerulonephritis and 18 with glomerulonephritis with nephrosis syndrome. The in vitro and in vivo effect of corticosteroid treatment on enzyme activity was also investigated. Cathepsin D-like activity appeared measurably in the sera of all patient groups but not in controls. The highest values were found in SLE patients. The increase in serum activity correlated with renal involvement. In vivo corticosteroid treatment significantly decreased serum activity in all groups except in systemic sclerosis patients. In vitro prednisolone treatment decreased enzyme activity in a dose-dependent manner. Determination of serum cathepsin D-like activity seems to be useful in the establishment of diagnosis and prognosis of SLE. Cathepsin D may be of pathogenetic significance in autoimmune disease especially in SLE.

Adrenal Cortex Hormones↗
PubMed1989

Treatment of systemic lupus erythematosus (SLE) with piroxicam (Hotemin-Egis).

Thirty patients suffering from systemic lupus erythematosus (SLE) were treated with daily 20 mgs of piroxicam (Hotemin). The patients were in a mildly active stage of the disease, taking maintenance doses of corticosteroids. The duration of piroxicam therapy was 3 months. Allergy was observed in one case, intolerance (gastrointestinal symptoms, nausea, vomiting) in two; these resulted in the cessation of therapy. Twenty seven patients were on piroxicam therapy for 3 months. Signs of clinical activity diminished, corticosteroid requirement decreased, subjective complaints were reduced. The drug was tolerated. In 3 cases, due to mild water retention, diuretics were given. Gastrointestinal symptoms, transaminase elevation, changes in blood cell counts were not observed during the 3 months period.

Adolescent↗
PubMed1989

Short term treatment of type II hyperlipoproteinaemia with silymarin.

In a seven-month open clinical study on 14 type-II hyperlipidaemic outpatients, the effects of silymarin (Legalon), an antioxidant and hepatoprotective agent, were investigated. Blood lipid, lipoprotein and apolipoprotein concentrations, as well as liver and renal function parameters were measured. After determining baseline values, patients were treated with 420 mg Legalon daily for three months. After a two-month placebo period, the treatment was repeated with Legalon for a further month. In respect to the serum lipid and lipoprotein concentrations, there were no remarkable changes except that the total cholesterol and HDL-cholesterol levels slightly decreased. At the 12th week, in all cases, the apolipoprotein levels were somewhat decreased compared to the baseline values. By the significant decrease of both apo A-I and A-II values, a decrease of the total structural protein amount of HDL, and thus a relative increase in the proportion of cholesterol in HDL fraction was suggested. There were minor changes in serum protein concentration and liver function tests, but all values remained within the normal range. All of the renal function parameters remained unchanged during both treatments and the placebo periods. An additive role of Legalon in the therapy of secondary hyperlipoproteinaemia resulting from different liver diseases is discussed.

Cholesterol↗
PubMed1988

Regulation of the dephosphorylation of phosphorylase A by glucose, AMP and polyamines.

1. The effect of glucose, caffeine, AMP and polyamines was investigated on the dephosphorylation of phosphorylase a by the catalytic subunits of protein phosphatase-1 and -2A. 2. Caffeine at 1-20 microM inhibited the dephosphorylation of the dimeric phosphorylase a at 37 degrees C using skeletal muscle enzymes; 0.1-10 mM of caffeine enhanced the rate of dephosphorylation greatly at 13 degrees C and slightly at 37 degrees C. 3. alpha-D-Glucose was more effective in accelerating both the dephosphorylation and the tryptic digestion of phosphorylase a than the beta-anomer. 4. Polyamines were found to moderate the inhibitory effect of AMP at concentrations which may occur in the tissues. In the presence of 5 mM glucose polyamines could cancel the AMP inhibition of the dephosphorylation of liver phosphorylase a by hepatic protein phosphatase-1 and -2A.

Adenosine Monophosphate↗
PubMed1988

The antigen/receptor specificity of antigranulocyte antibodies in patients with SLE.

The antigen/receptor specificity of antigranulocyte antibodies (AGAs) detected in the sera of patients with systemic lupus erythematosus (SLE) was investigated by inhibitory immunofluorescence test and Western immunoblotting technique. The interactions of AGAs with antigens of intact normal granulocytes were determined by inhibiting the binding of different myeloid monoclonal antibodies (mAbs). Seven of the studied 12 sera revealed binding to CD15 (X hapten) and/or to CD16 (FcR1o). The specificity investigation of AGAs was completed with Western immunoblotting technique. The binding of AGAs to bands with Mr of about 50-60 kDa and at 30 kDa on unstimulated granulocyte plasma membrane preparation could be demonstrated from 4 out of 6 AGA positive SLE sera. The cause of the disappearance of bands on the phorbol-myristate-acetate (PMA) activated membrane except those of the 50-60 kDa bands is still to be discovered.

Adult↗