Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:3.4.21.5 (thrombin)
33,306 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Treatment of platelets (10(9) cells/ml) with thrombin (1 U/ml) resulted in rapid disappearance of fibrinogen from the system as measured by the tanned red cell hemagglutination inhibition immunoassay (TRCHII). Plasmin digestion of individual pellet and supernatant fractions that had been previously separated from thrombin-treated platelet suspensions by centrifugation resulted in recovery of TRCHII-detectable material in platelet pellets. To elucidate the specific association of fibrin to platelet membranes, control and thrombin-treated platelets were homogenized by a modified glycerol-loading and nitrogen decompression technique. Ultracentrifugation of homogenates through 27% sucrose cushions yielded three subcellular fractions: supernatant, small membrane vesicles, and a particulate fraction for controls; and supernatant membrane vesicles, and aggregated membrane "ghosts" for thrombin preparations. Ultrastructurally identifiable fibrin was noted only in the thrombin fraction containing membrane ghosts. Fibrinogen recovered from 3 thrombin fractions was markedly decreased (3% of the control). Plasmin digestion produced 23% and 46-fold increase in TRCHII-detectable material from 3 subcellular fractions of control and thrombin preparations, respectively. More than 97% of TRCHII material recovered from thrombin preparations was in the fraction containing aggregated membrane fractions. Results suggest that platelet plasma membranes function as surfaces for fibrin deposition.
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PMID:Localizaton of fibrin converted by thrombin from released platelet fibrinogen. 644 58

Of four Holstein-Friesian calves infected with 200,000 sporocysts of Sarcocystis bovicanis, three become ill and died on days 35, 55, and 59 of a 63-day experiment. No control calves became ill or died. Serum biochemicals and hematologic indicators of hemostasis from both groups were measured throughout the experiment. Creatine phosphokinase values for both groups increased markedly during acute infection. Lactic dehydrogenase and aspartate aminotransferase values were high in infected calves on days 25 to 35 and days 24 to 63, respectively, indicating injury of muscle, liver, or other tissues. Sorbitol dehydrogenase values were significantly higher for infected than for control calves on days 25 and 35, indicating liver injury. Serum bilirubin and blood urea nitrogen values were significantly increased in three anemic infected calves from day 25 or 26 to day 35, probably reflecting destruction of erythrocytes. The fourth infected calf was not anemic and had no hyperbilirubinemia and only minimal azotemia. Serum protein and albumin values decreased in infected calves on days 21 to 30 or 35, when, although hypoalbuminemia persisted, total protein concentration increased. Glucose, calcium, sodium, and chloride values decreased in infected calves slightly before onset of illness and remained low throughout the experiment. Potassium, magnesium, and phosphorus values did not differ between infected and control calves. Activated partial thromboplastin time and Russell's viper venom time were normal; prothrombin time was significantly higher from day 27 to day 49 in infected calves. This pattern was interpreted as evidence for acquired factor VII deficiency. Abnormal retraction of blood clots and enlarged platelets in blood smears, which indicate platelet dysfunction and increased platelet turnover, respectively, were seen on days 27 through 35 in anemic infected calves. Values for thrombin time (three calves) and fibrin degradation product concentration (one calf) increased just before death of the infected calves.
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PMID:Hematology of experimental acute Sarcocystis bovicanis infection in calves. II. Serum biochemistry and hemostasis studies. 678 37

Infusion of thrombin and the fibrinolysis inhibitor tranexamic acid during ether anaesthesia in the rat gives rise to fibrin deposition in the renal glomeruli. This resulted in renal insufficiency as indicated by an increase in the serum urea nitrogen, reduction in the renal blood flow and patchy cortical necrosis in the kidneys. The plasma renin activity was elevated initially probably due to the ether anaesthesia. Infusion of the angiotensin II antagonist saralasin prevented the renal insufficiency if it was given during the thrombin infusion but not if it was given afterwards. The deposition of fibrin in the kidneys was also reduced. The results indicate that angiotensin II is involved in the pathogenesis of the renal injury.
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PMID:Protective effect of angiotensin II inhibition on acute renal failure after intravascular coagulation in the rat. 703 9

Two to five units of platelet concentrate were frozen together in single bags using glycerol-glucose as cryoprotective agents and a special freezing plate which produced a reproducible, rapid freezing rate when immersed in liquid nitrogen. After thawing there was no loss in platelets compared to prefreezing controls. Phase microscopic evaluation after thawing, however, demonstrated large numbers of severely damaged platelets and a significant decrease in morphology score. Total ATP levels fell to 37-52% of controls, and thawed platelets did not aggregate with adenosine diphosphate or collagen or undergo release of nucleotides following incubation with thrombin. In vivo recovery one hour after transfusion of autologous platelets administered to patients with leukemia was significantly inferior (p less than 0.025) to results achieved in the same patients with autologous platelets frozen with dimethylsulfoxide. These results indicate that significant damage occurs following freezing and thawing utilizing glycerol-glucose as cryoprotective agents for frozen platelets and that further investigation is required prior to their clinical use. Blood banks currently interested in platelet cryopreservation for clinical use should utilize dimethylsulfoxide as a cryoprotective agent.
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PMID:Cryopreservation of platelet concentrates using glycerol-glucose. 707 14

A series of N alpha-(arylsulfonyl)-L-arginine amide derivatives having carboxamide N-substituents with a carboxyl group was prepared and tested as inhibitors of the clotting activity of thrombin. The most inhibitory compounds were obtained when a carboxyl group was introduced into the carbon next to the amide nitrogen of N alpha-(arylsulfonyl)-L-arginine amide derivatives, e.g., N alpha-(arylsulfonyl)-L-arginyl-N-butyl-, N-(methoxyethyl)- or N-(tetrahydrofurfuryl)glycine and 4-alkyl-1-[N alpha-(arylsulfonyl)-L-arginyl]-2-piperidinecarboxylic acid, with an I50 of 1-3 X 10(-7) M.
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PMID:Thrombin inhibitors. 3. Carboxyl-containing amide derivatives of N alpha-substituted L-arginine. 745 81

The effects of oligotide, an oligodeoxyribonucleotide analog, were investigated in an experimental model of traumatic shock. Pentobarbital-anesthetized rats subjected to Noble-Collip drum trauma and receiving only the vehicle (i.e., Krebs-Henseleit solution) developed a severe form of traumatic shock characterized by marked hypotension (61 +/- 6 mmHg), a survival time of 115 +/- 21 min, endothelial dysfunction, significant increases in plasma free amino-nitrogen concentration (p < .001) as well as elevated intestinal myeloperoxidase activity. In contrast, oligotide given intravenously (15 mg/kg bolus + 10 mg/kg/h infusion for 5 h) resulted in a significant prolongation of survival time to 209 +/- 31 min (p < .01), a significant and sustained increase in mean arterial blood pressure, a significant attenuation of plasma free amino-nitrogen concentration (p < .01), and intestinal myeloperoxidase activity (p < .05). Furthermore, oligotide significantly preserved superior mesenteric artery (SMA) endothelial function as seen by the relaxation response of isolated SMA rings to acetylcholine (71 +/- 5% vs. 36 +/- 5%, p < .01 compared to untreated trauma rats). Moreover, oligotide in a concentration-dependent manner attenuated unstimulated human neutrophil adherence to either thrombin or trauma-activated SMA endothelium in vitro (p < .001). Thus, our data suggest that the mechanism of the protective effect of oligotide in traumatic shock is improving endothelial function and diminishing neutrophil accumulation leading to reduced tissue injury.
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PMID:Beneficial effects of oligotide, a novel oligodeoxyribonucleotide, in murine traumatic shock. 753 3

The crystal structure of a complex between a bivalent peptidyl pyridinium methyl ketone inhibitor and human alpha-thrombin has been solved and refined at 2.0 A to an R factor of 0.18. The inhibitor, (D)cyclohexylalanine-Pro-Arg-(CH2N+C5H4CH2CO)-(Gly)4-Asp- Tyr-Glu-Pro-Ile-Pro-Glu-Glu-Ala-cyclo-hexylalanine-(D)Glu (coded P596), which forms a reversible covalent complex with thrombin, is highly potent with a Ki = 4.6 +/- 1.0 x 10(-14) M, lower than that of recombinant hirudin. The N-terminal, active-site-directed portion of the inhibitor is linked to the fibrinogen recognition exosite binding portion by a tetraglycine segment. The strong electron-withdrawing effect provided by the permanent positive charge on the pyridinium nitrogen makes the arginyl carbonyl carbon more susceptible to nucleophilic attack. In the crystal, a covalent P596-thrombin complex is observed. The electron density surrounding the active site portion and the pyridinium of the inhibitor is very well defined, clearly showing the existence of a covalent bond between the Ser195 O gamma and the now tetrahedral carbon of the inhibitor. The decreased binding ability of thrombin inhibitors containing N-terminal acetylation is discussed as is the effect of replacing the P3 (D)phenylalanine with (D)cyclohexylalanine. The electron density surrounding the remainder of the inhibitor is generally well defined, the exceptions being the C-terminal (D)Glu, the highly flexible tetraglycine linker, and some of the solvent-directed side chains.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Crystal structure of a peptidyl pyridinium methyl ketone inhibitor with thrombin. 754 84

Endotoxin(lipopolysaccharide = LPS), cell wall component of gram-negative bacteria, activates monocytes and macrophages to release cytokines, reactive nitrogen intermediates (RNI), and to generate tissue factor(TF) which initiate coagulation. We have purified 7kDa and 18kDa cationic antibacterial proteins (CAP-7 and CAP-18) with LPS-binding and LPS-neutralizing activities from rabbit granulocytes using as an assay the agglutination of erythrocytes coated with Re-LPS. From protein sequencing, CAP-7 was identified as the C-terminal 37 amino acid fragment of CAP-18. Synthetic peptide #197 (identical sequence to CAP-7, Gly1-Try37) and #36-1 (a truncation of CAP consisting of 32 amino acid residues, Gly1-Ala32) showed LPS-binding activity. Each peptide inhibited LPS-induced tissue factor(TF) generation by murine peritoneal macrophages, even added 1-3 hours after stimulation of cells with LPS. C57BL/6 mice treated with #197 were significantly protected from lethal LPS challenge. Peptide #36 also blocked the LPS-induced lethality. These peptides had antibacterial activity to gram-negative bacteria, such as E.coli, S.typhimurium, K.pneumonia, Ps.aeruginosa and also to gram-positive S.aureus (Methicillin sensitive and resistant strains). Both peptides inhibited TF- and Xa-induced plasma clotting. Using synthetic chromotogenic substrates, both CAP7 peptides blocked the coagulation cascade at two sites, activation of factor X to Xa and conversion of Factor II (prothrombin) to factor IIa (thrombin). In vivo treatment of peptide #197 prevented acute lethality in mice injected with tissue factor (rabbit brain thromboplastin). Two other peptides, #32(Gly1-Phe9) and #50(Ile13-Typ37) failed to demonstrate LPS-binding, LPS-neutralizing, antibacterial and anticoagulant activities. The active peptides but not the inactive peptide maintain a putative heparin binding domain at their N-termini. This heparin binding domain is participate in the LPS-binding, LPS neutralizing, antibacterial and anticoagulant activities of CAP7. These active peptides may have a therapeutic potential for treatment for DIC due to sepsis and endotoxin shock.
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PMID:Endotoxin-binding synthetic peptides with endotoxin-neutralizing, antibacterial and anticoagulant activities. 783 55

Recently, we showed that levels of circulating free fatty acids are increased in women who later develop pre-eclampsia long before the clinical onset of the disease. Among the serum free fatty acids, oleic-, linoleic-, and palmitic acid were found to be increased by 37, 25 and 25%, respectively. In the present study we asked if these free fatty acids can interfere with endothelial cell functions. Cultured endothelial cells were exposed to linoleic-, oleic- and palmitic acid in concentrations ranging from 0.016 to 0.133 mumol ml-1, resulting in molar ratios of free fatty acids to albumin of 0.2-1.6. We found that among these fatty acids, linoleic acid reduced the thrombin-stimulated prostacyclin release by 30-60%, oleic acid by 10-30%, whereas palmitic acid had no effect. Endothelial cells incubated in presence of linoleic acid showed a concentration-dependent reduction in prostacyclin release in response to thrombin, and cells incubated with linoleic acid for up to 28 h, showed a reduced thrombin-induced prostacyclin release at every time point. Endothelial level of cGMP mainly reflected the synthesis of endothelium-derived relaxing factor/nitrogen monoxide (EDRF/NO), since blocking of the endogenous production of EDRF/NO with N-omega-nitro-L-arginine, resulted in about 90% reduction in cGMP-content of the endothelial cells. Incubation with linoleic acid reduced the endothelial cGMP level by 70%. Linoleic acid reduced the endothelial cells ability to inhibit platelet aggregation by 10-45%, (p = 0.0019). It was concluded that linoleic acid impedes the ability of the endothelial cells to produce prostacyclin and cGMP, and to inhibit platelet aggregation.
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PMID:Effects of free fatty acids found increased in women who develop pre-eclampsia on the ability of endothelial cells to produce prostacyclin, cGMP and inhibit platelet aggregation. 786 32

1. Chronic granulomatous disease (CGD) is a group of genetic disorders characterised by recurrent severe suppurative infections due to impaired microbial killing. The principal biochemical defect is an impairment in the production of reactive oxygen intermediates by phagocytes. 2. Nitric oxide (NO) is synthesised from the guanidino nitrogen atom(s) of L-arginine and has recently been proposed to be involved in defence mechanisms. The aim of this study was to investigate the involvement of the oxidative burst in the biosynthesis of NO by neutrophils and mononuclear cells from patients with CGD. 3. NO synthesis was assayed by the ability of neutrophils and mononuclear cells to inhibit thrombin-induced washed platelet aggregation while superoxide anion (O2-) production was measured spectrophotometrically by the superoxide dismutase inhibitable reduction of cytochrome c. 4. Neutrophils and mononuclear cells from patients with CGD released NO. This release was inhibited by nitro-L-arginine methyl ester but could be reversed by L-arginine. Zymosan- and PMA-induced O2- production was less than 10% as compared with healthy controls. 5. These results indicate that O2- production is not essential for NO synthesis in human leucocytes.
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PMID:Neutrophils and mononuclear cells from patients with chronic granulomatous disease release nitric oxide. 839 Feb 77


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