Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.4.21.6 (thromboplastin)
 13,278 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Serial determinations of beta-thromboglobulin (BTG), platelet factor 4 (PF4), fibrinopeptide A (FPA), antithrombin III (ATIII), protein C (PC), fibrin (ogen) degradation product (FDP), FDP D-dimer, activated partial thromboplastin time (APTT), prothrombin time (PT), and euglobulin lysis time (ELT) were performed in 18 patients with non-progressing stroke and 14 patients with progressing stroke in order to predict the development of progressing stroke. Increasing levels of BTG, PF4 and FDP with frequent fluctuation were noted in both kinds of stroke. Fluctuation of FPA levels was also noted but was less pronounced. PC levels were found to be slightly decreased with fluctuation but the mean was still in the lower normal limit. BTG, PF4 and PC all elevated at the time of deterioration of physical condition in patients with progressing stroke, whereas FPA had no definite change at that time. From our study, we conclude that both platelet activation and coagulation process do occur in both kinds of stroke. But the latter plays a minor role in the formation of thrombosis. The hemostasis change, especially concerning the thrombosis formation, probably plays a role in the development of progressing stroke, but we cannot predict their development even by the detections of the newly known molecular substances appearing in various steps of the hemostatic mechanism. Development of new tests for understanding the whole dynamic change of the thrombosis process is necessary for accurate prediction of the progressing stroke in the future.
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PMID:The serial hemostasis-related changes in patients with cerebral infarction: comparison between progressing and non-progressing stroke. 253 1

Eighteen patients undergoing aortobifemoral graft surgery for severe aortoiliac atherosclerotic disease received a bolus injection of 10,000 anti-Xa units of either unfractionated heparin (UFH) or low molecular weight heparin (LMWH) into the distal aorta as prophylaxis against thromboembolic complications related to clamping. Heparin activity was measured by factor Xa inhibition and by prolongation of the APTT. In both groups there was a delay before peak levels of heparin were observed. In the LMWH group, this amounted to 30 min. In the UFH group, APTT was prolonged by 46 s, 7 min after injection but only by 5 s at the end of the operation. In contrast, in the LMWH group, the prolongation in APTT 7 min after injection was less (34 s) but more sustained since a 12.5 s prolongation was still present at the end of the operation. During surgery, heparin activity exceeded 0.7 U/ml in the LMWH group, compared to significantly lower levels in the UFH group (less than or equal to 0.20 U/ml). By the end of the operation no heparin activity was detectable in the UFH group. Protein C antigen decreased after heparin injection and this fall was more pronounced in the UFH group. The level of C1q (a subcomponent of the first component of the complement system) was decreased in the UFH group (P less than 0.04), whereas in the LMWH group C1q levels increased. Platelet aggregation with collagen was inhibited to a significantly greater degree in the LMWH group than the UFH group (54% compared with 23%) (P less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:The effect of a bolus injection of unfractionated or low molecular weight heparin during aortobifemoral bypass grafting. 254 Oct 26

A complex composed of factor Xa and phospholipid vesicles assembled in the presence of calcium ions catalyzes a discrete cleavage of the heavy chain of bovine protein C that is indistinguishable from that produced by thrombin as judged by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. This cleavage generates an active site capable of hydrolyzing small substrates and inactivating factor Va function in the prothrombinase complex. Activation of protein C by factor Xa requires both calcium ions and phospholipid vesicles and proceeds at a rate an order of magnitude greater than that observed for alpha-thrombin in solution. gamma-Carboxyglutamic acid-domainless protein C is not activated by factor Xa, consistent with the requirement for phospholipid and distinguishing this reaction from protein C activation by thrombin. Thrombomodulin serves as a cofactor for the factor Xa-catalyzed reaction, forming a 1:1 complex with factor Xa (apparent Kd = 5.7 X 10(-10) M) and stimulating the saturated rate of protein C activation by factor Xa (kcat = 149 min-1) to levels comparable with the thrombin-thrombomodulin complex. Protein C activation by factor Xa is not inhibited by the specific thrombin inhibitor dansyl-N-(3-ethyl-1,5-pentanediyl)amide but is inhibited by antithrombin III, tripeptide-chloromethyl ketones, and the monoclonal antibody alpha-BFX-2b that is highly specific for factor Xa. These data indicate that thrombomodulin is promiscuous in its role as a cofactor and suggest the existence of an alternative pathway for protein C activation in vivo.
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PMID:The activation of bovine protein C by factor Xa. 255 Apr 35

Plasma protein C inhibitor (PCI) was purified to homogeneity (greater than 95%) with good recovery (greater than 25%) and reproducibility, and the inhibition of a number of blood clotting and fibrinolytic enzymes by purified PCI was studied. PCI inhibited activated protein C (APC), two-chain urokinase (2c-uPA), two-chain tissue plasminogen activator (2c-tPA), thrombin, factor Xa, plasma kallikrein and factor XIa, and this inhibition was accelerated by heparin. The inhibition of each enzyme was accompanied by formation of enzyme inhibitor complexes and by degradation of the inhibitor to lower molecular weight derivatives. Plasma kallikrein and factor XIa cleaved PCI of native Mr = 57,000 into two products with Mr = 54,000 and 52,000 whereas the other enzymes converted the PCI to a product with Mr = 54,000. PCI did not detectably inhibit alpha-factor XIIa or plasmin. Kinetic studies using PCI yielded the following second-order rate constants for inhibition of human APC, 2c-uPA, 2c-tPA, thrombin, factor Xa, kallikrein and factor XIa respectively: 0.65 x 10(4), 0.22 x 10(4), 0.08 x 10(4), 0.61 x 10(4), 2.01 x 10(4), 6.50 x 10(4), and 9.03 x 10(4) M-1s-1 in the absence of heparin and 1.58 x 10(6), 0.43 x 10(6), 0.03 x 10(6), 0.52 x 10(6), 0.09 x 10(6), 0.18 x 10(6) and 0.74 x 10(6) M-1s-1 in the presence of optimal concentrations of heparin. The rate constants for the inhibition of factor XIa and 2c-uPA by PCI suggest a possible role of PCI in the physiologic regulation of these enzymes. The second order rate constants for inhibition of bovine APC and Gla-domainless bovine APC by human PCI were 0.61 x 10(4) and 0.26 x 10(4) M-1s-1 in the absence of heparin and 0.54 x 10(6) and 0.71 x 10(6) M-1s-1 in the presence of heparin, respectively. Calcium ions (0.05 to 4 mM) did not affect these rate constants. The results obtained with normal and Gla-domainless APC indicate that the Gla domain of APC is not required for inactivation by PGI and is not essential for the heparin stimulation of this reaction.
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PMID:Purification and characterization of plasma protein C inhibitor. 255 Oct 64

Combined deficiency of factor V and factor VIII, a rare bleeding disorder, was found in a 43 year-old male. He had often presented manifestations of easy bruising since childhood, but none of his family had shown evidence of a bleeding tendency. We examined him and his family as far as we could and his abnormality of blood coagulation was apparent, but the members of his family were normal. The prothrombin time and activated partial thromboplastin time of this patient were prolonged, but his thrombin time was normal. Factor V and factor VIII coagulant activity were low, but von Willebrand factor antigen and activity (ristocetin cofactor activity) levels were normal. Protein C and Protein C inhibitor antigen and activity levels were also found to be normal. Following 1-deamino-8-D-arginine vasopressin (DDAVP) injection, he had immediate increases in factor VIII coagulant activity, but both von Willebrand factor antigen, activity levels and factor V coagulant activity remained low. Moreover, there was no rapid decline in factor VIII complex activity. These findings suggest that the endogenous factor VIII in this patient is metabolized normally and that at least the deficiency of factor VIII does not result from accelerated degradation in plasma.
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PMID:[DDAVP administration in a case of congenital combined factor V and factor VIII deficiency]. 260 19

Using affinity chromatography on a column of factor X-Cellulofine, we have isolated a novel blood coagulation factor X-binding protein with anticoagulant activity from the venom of Trimeresurus flavoviridis (Habu snake). This anticoagulant protein was also purified by chromatography on Sephadex G-75 and S-Sepharose Fast Flow. The yield of the purified protein was approximately 16 mg from 400 mg of crude venom. The purified protein gave a single band on both analytical alkaline disc-gel electrophoresis and SDS-PAGE. This protein had a relative molecular weight (Mr) after SDS-PAGE of 27,000 before reduction of disulfide bonds and 14,000 after reduction of disulfide bonds. The protein prolonged the clotting time induced by kaolin or factor Xa. In the presence of Ca2+, it formed a complex with factor X, the molar ratio being 1 to 1. Similar complex formation was observed with factor Xa and factor IX/factor IXa, but not with other vitamin K-dependent coagulation factors, i.e., prothrombin, factor VII, protein C, protein S, and protein Z. The interaction of this anticoagulant protein with factor IX/factor X was dependent on gamma-carboxyglutamic acid (Gla) domains, since Gla-domainless derivatives of factor X and factor IXa beta' did not interact with this anticoagulant protein.
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PMID:A novel blood coagulation factor IX/factor X-binding protein with anticoagulant activity from the venom of Trimeresurus flavoviridis (Habu snake): isolation and characterization. 261 88

Influence of the protein C activator from snake venom on blood coagulation was studied. Incubation of different concentrations of the activator with rat blood plasma resulted in a dose-dependent prolongation of the activated partial thromboplastin time (APTT). Cleavage of the protein C to the active form was detected by electrophoresis. Intravenous administration of the activator (100 mg/kg) into rats led to prolongation of APTT to 242 +/- 80%, to increase in the plasminogen activator level to 145 +/- 29% and to decrease in the factor V activity to 57 +/- 14%. When thrombosis was induced by means of administration of the thromboplastin lethal dose, pretreatment with the activator prevented animal death in 90% of cases. The effects of the activator observed appear to occur via transformation of the endogenous protein C into its active form.
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PMID:[Antithrombotic effect of protein C activator from a snake venom]. 261 27

To elucidate the role of protein C (PC) in the release of plasminogen activator inhibitor (PAI) from endothelial cells, the effect of PC and activated protein C (APC) on plasma levels of PAI in endotoxin (ET)-treated rats was examined. When activated by snake venom, human PC significantly prolonged the activated partial thromboplastin time (APTT) of both human and rat plasma samples. Addition of APC also prolonged the APTT of both human and rat plasma samples. PAI activity in plasma from septicemic patients and ET-treated rats was neutralized by APC. A small dose of ET (0.1 microgram/kg) gradually increased plasma PAI activity, which became maximum 3h after ET-treatment. APC administered prior to ET-treatment, PC decreased PAI activity, however, no such inhibition was seen when administered after ET-treatment. A significant negative correlation between PC concentrations and PAI activities was observed in plasma from septicemic patients. These findings indicated that activation of PC on endothelial surface plays a regulatory role in releasing PAI and that endotoxin might inhibit the surface activation of PC.
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PMID:[Role of protein C in endotoxin-induced release of plasminogen activator inhibitor from endothelial cell]. 261 61

As part of a European multicentre prospective study involving the measurement of a number of haemostatic factors, a quality assessment (QA) scheme was organized. This paper describes the preparation, design and results of the first QA exercise, involving 16 European laboratories and 10 haemostatic assays. The design allowed the investigation, for each assay, of the variability between duplicates and the variability between days within each centre, and of the agreement between centres. A graphical presentation of each centre's performance in comparison to that of others was adopted, which preserved the confidentiality of each centre's results. The factor VIII clotting activity assay (VIII:C) and the rocket immuno-electrophoresis assays of von Willebrand factor related antigen (vWF R:Ag), antithrombin III, protein C and histidine-rich glycoprotein showed the highest between-duplicate and between-day coefficients of variation (CVs), whereas the clotting assays of activated partial thromboplastin time and fibrinogen had the lowest CVs. CVs for the enzymatic assays using synthetic substrates of antithrombin III, plasminogen and alpha-2-antiplasmin were between these extremes. The between-centre CVs were high for both the VIII:C and vWF R:Ag assays. The QA exercise showed that, in multicentre studies involving the measurement of haemostatic factors, it is feasible to undertake analysis locally at each centre.
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PMID:The measurement of haemostatic factors in 16 European laboratories: quality assessment for the Multicentre ECAT Angina Pectoris Study. Report from the European Concerted Action on Thrombosis and Disabilities (ECAT). 266 75

Eighty patients undergoing total hip replacement (THR) were randomly allocated to three groups. Group I (n = 29) received general anaesthesia, Group II (n = 29) epidural anaesthesia and Group III (n = 22) the same epidural as Group II and the same general anaesthesia as Group I but with a lower isoflurane concentration. Prothrombin time (PT), activated thromboplastin time (APTT), fibrinogen (FG), plasminogen (PG), antithrombin III (AT III), protein C (Proc C), alpha-2-antiplasmin (alpha 2AP), Factor VIII coagulating activity (F VIII:C), von Willebrand factor antigen (vWF:Ag), von Willebrand ristocetin cofactor (vWF:Rcof), tissue plasminogen activator (tPA) as antigen and activity were measured before induction (A), at the end of surgery (B), on the first postoperative morning (C) and 7 days postoperatively (D). The most relevant finding was that AT III was equally depressed immediately after surgery in all groups, but returned to normal significantly faster in the epidural group (mean values at C: 96.2% in Group I, 104.1% in Group II, 92.7% in Group III). The faster return to normal of AT III after epidural anaesthesia could be one of the mechanisms responsible for the beneficial effect of this technique on the prevention of thromboembolic complications.
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PMID:Coagulation and fibrinolytic parameters in patients undergoing total hip replacement: influence of the anaesthesia technique. 268 46


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