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:3.4.21.6 (thromboplastin)
13,278 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We evaluated a recently developed commercial assay for quantifying thrombin-antithrombin III (TAT) complexes in human plasma. The assay is precise (within-assay CV less than 10%, between-assay CV less than 13%), and sensitive (detection limit 0.7 micrograms of TAT per liter of plasma). Measurements for healthy volunteers yielded a normal reference (95 percentile) interval of 0.8 to 5.0 micrograms/L (n = 50, mean 2.1 micrograms/L, range 1.1 to 7.5 micrograms/L). TAT concentrations were increased in 25 of the 41 patients who fulfilled the clinical criteria of disseminated intravascular coagulation (DIC, overall mean 15.8 micrograms/L) and in 30 of the 35 patients with deep-vein thrombosis of the leg (overall mean 9.4 micrograms/L). We assessed the accuracy of the TAT assay by comparison with established criteria for the laboratory diagnosis of DIC involving various cutoff values for antithrombin III, factor V, fibrinogen, platelet count, fibrin/fibrinogen degradation products, and activated partial thromboplastin time. The low specificity of the TAT assay with regard to some of these criteria indicates that the latter are probably insensitive.
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PMID:Laboratory and clinical evaluation of an assay of thrombin-antithrombin III complexes in plasma. 316 16

The pharmacokinetics of recombinant hirudin were studied in 9 healthy subjects after single intravenous, subcutaneous or intramuscular doses of 0.1 mg/kg. Generally, administration of r-hirudin was tolerated without side effects. An assay was used which detects the inhibitor in blood and urine by its antithrombin activity. Absorption, distribution and elimination of r-hirudin were found to be corresponding to the results obtained with native hirudin. The effects on the haemostatic system were evaluated. Thrombin time and partial thromboplastin time were prolonged dependent on the r-hirudin plasma level. Platelet counts, fibrinogen level and fibrinolytic system were unchanged. Bleeding time was not prolonged. After administration of r-hirudin in case of chronic DIC, fibrinogen level, platelet counts and fibrin monomers transiently returned to normal values.
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PMID:Clinico-pharmacological studies with recombinant hirudin. 322 82

FUT-175 is a newly synthesized serine protease inhibitor. In the present study, we investigated the effects of FUT-175 on blood coagulation and experimental DIC. The effects on coagulation were examined in vitro by measuring the activated partial thromboplastin time (APTT), prothrombin time (PT) and thrombin time (TT) of rat plasma in the presence of FUT-175. FUT-175 exhibited remarkable anticoagulative effects to prolong APTT at a plasma concentration of 3 x 10(-7) M, PT at 1 x 10(-5) M and TT at 3 x 10(-5) M. The anticoagulative effect of FUT-175 at 1 x 10(-6) M on APTT was almost similar to that of heparin at 0.3 U/ml or that of gabexate mesilate at 1 x 10(-3) M. Experimental DIC was induced by a four-hr sustained intravenous infusion of endotoxin. FUT-175 was administered intraperitoneally prior to the injection of endotoxin or infused intravenously with endotoxin. As a result, the prolongation of APTT and PT, the decreases of fibrinogen level, platelet counts and complement level, and the increase of FDP were remarkably improved by FUT-175. Furthermore, glomerular fibrin deposits were reduced by the infusion of FUT-175. These results indicate that FUT-175, having a potent inhibitory effect on blood coagulation, is clinically applicable to therapy for DIC.
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PMID:[The effects of FUT-175 (nafamostat mesilate) on blood coagulation and experimental disseminated intravascular coagulation (DIC)]. 344 13

Reversible acute disseminated intravascular coagulation (DIC) has been induced in dogs by intravenous injection of homologous tissue thromboplastin. There was no measurable consumption of antithrombin III and heparin cofactor II even if fibrinogen was reduced during DIC by more than 80% of its baseline. The prothrombin level remained practically constant. These data correspond to the generation of a few nanomoles of thrombin in vivo with subsequent pseudo-first order inactivation by the major thrombin inhibitors. An ex vivo measure of the pseudo-first order rate constant (dynamic thrombin inhibitory capacity, DTIC) was a sensitive probe of circulating heparin. There was no change of DTIC during DIC in the absence of exogenous heparin suggesting that heparin-like endogenous glycosaminoglycans were not released in substantial amounts. Pretreatment with heparin efficiently inhibited the development of tissue thromboplastin induced DIC. This animal model may serve as a tool for the study of glycosaminoglycan anticoagulants in vivo.
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PMID:Tissue thromboplastin induced reversible DIC and heparin-enhanced inhibitors in dogs. 351 33

Intravenous injection of homologous lung or brain tissue thromboplastin in dogs under general anesthesia induced changes of conventional hemostasis variables consistent with acute DIC (prolongation of prothrombin times, thrombin times, APTT, drop of fibrinogen and a transient reduction of the platelet count). The animals reacted with accelerated respiration and pulse rates. After recovery from anesthesia they resumed their normal activity as before. Fibrinogen reached a minimum within 40 min after the DIC trigger dose had been injected. Dependent on the size of the latter up to 80% of clottable fibrinogen was consumed. No consumption of antithrombin III and heparin cofactor II could be demonstrated by functional assays based on thrombin inhibition by diluted plasma in the presence of heparin or dermatan sulfate. Prothrombin measured amidolytically by an Echis Carinatus venom assay remained practically unchanged. These findings are consistent with free thrombin concentrations in the nanomolar range sufficient to clot fibrinogen rapidly without visibly affecting the up to 1,000 fold higher concentrations of inhibitors and prothrombin. Heparin administered before tissue thromboplastin virtually suppressed the evolution of DIC but its protective effect was overcome by higher trigger doses. Heparin injected after the induction of DIC had no protective effect. The reversible DIC model in dogs may be a promising tool to study activated coagulation in vivo at practically constant inhibitor concentrations. One dog can be used for several acute experiments with homologous tissue thromboplastin, thus the number of animals and their costs may remain within reasonable limits.
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PMID:Heparin-enhanced inhibitors during reversible disseminated intravascular coagulation. 386 25

Tissue thromboplastin generation in monocytes was studied during various stages of Escherichia coli endotoxinaemia in pigs. The pigs were monitored in halothane anaesthesia and mechanically ventilated. Blood was sampled from the superior caval vein before and during endotoxin infusion and up to 6 hours after its start. Monnuclear leukocytes were harvested with Lymphoprep separation and monocyte counts were made, using TRITC-labelled sheep erythrocytes, acridine orange and a fluorescence microscope. Thromboplastin was quantified in a two-stage assay by incubating the test sample together with purified factor X, factor VII and Ca++. The generated factor Xa was thereafter assayed. There was statistically significant increase of tissue thromboplastin activity in monocytes after endotoxin infusion. Maximum level was reached at the end of the infusion and was maintained throughout the observation period. Decrease occurred in platelets, leukocytes, antithrombin III, fibrinogen and clotting factors V, VII and VIII, and clotting time was prolonged. These findings indicated significant disseminated intravascular coagulation. The endotoxin-stimulated monocytes with their elevated tissue thrombo-plastin activity thus may play an important part in development of the DIC which so often follows septicemia.
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PMID:Tissue thromboplastin generation in circulating mononuclear phagocytes and development of coagulation disorders during E. coli endotoxinaemia in pigs. 392 66

A model was experimentally made with 2 hours serial infusion of thromboplastin (Tp) into rabbits to examine the drug's effect on a hemorrhagic tendency and to elucidate the coagulation and fibrinolytic system in acute DIC encountered in obstetrics, and the system was periodically observed. Groups given the drug, given it during pregnancy, those which bled massively, and those with accelerated fibrinolysis were prepared. The results are as follows. 1) Fibrinogen, PT, APTT, TEG, ELT, AT-III, antiplasmin activity, and platelet count varied markedly from the initiation of Tp injection, and returned to normal following termination. 2) Blood from the heparin dose group showed non-coagulation but decreases in the platelet count and fibrinogen were inhibited. 3) In the aprotinin dose group, serial 2 hour administration induced inhibition of fibrinolysis despite the relatively delayed appearance of anti-fibrinolytic activity. 4) No fibrinolytic effects were seen in anti-plasmin activity or ELT in the tranexamic acid dose group. 5) Lowering of parameters examined was marked in the Tp dose group during pregnancy. 6) The mortality rate up to 6 hours after Tp infusion was 54.5% with solely given, and 10% with group given drug. 7) Death within one hour of Tp infusion in the mass bleeding group, being rated for 50%, was improved to 16.7% by the pre-administration of urokinase.
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PMID:[Treatment of obstetrical disseminated intravascular coagulation--sequential changes of coagulation and fibrinolytic system in DIC rabbits]. 618 25

To study the haemodynamic, cellular and humoral changes seen during septicemia-endotoxinemia a relatively large animal is needed. Pigs are satisfactory in size but have a tendency to develop malignant hyperthermia reaction to stress situations and certain anaesthetic agents. This problem was solved using a screening test of halothane exposure. When later used for experiments, the nonresponding pigs developed the typical hypokinetic low-flow state after endotoxin challenge seen in the advanced stage of septicemia in man. Decreased number of circulating leucocytes and platelets, increased tissue thromboplastin production in monocytes, and a significant coagulation disorder (DIC) were observed. Release of oxygen radicals and lysosomal enzymes from leucocytes could be estimated. Endotoxin levels in plasma were easily measured. This pig model of controlled endotoxinemia correlates well with some important haemodynamic, cellular and humoral reactions observed during human in vivo observations and in vitro studies. This model may thus be a valuable tool in clinical research of endotoxinemia and septicemia.
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PMID:Controlled endotoxinemia in pigs. A suitable model for in vivo studies of some haemodynamic, humoral and cellular reactions. 653 28

The selective antimetastatic agents p-(3,3-dimethyl-1-triazeno)benzoic acid potassium salt (DM-COOK), 5-(3,3-dimethyl-1-triazeno)imidazole-4-carboxamide (DTIC) and (+/-)1,2-di(3,5-dioxopiperazin-1-yl)propane (ICRF-159) have been shown to markedly depress the formation of spontaneous hematogenous metastases in mice bearing s.c. Lewis lung carcinoma, with a mechanism unrelated to cytotoxicity for tumor cells. The effects on hemostasis of DM-COOK, DTIC and ICRF-159 have thus been examined in comparison with those of a purely cytotoxic agent, cyclophosphamide, in mice bearing i.m. Lewis lung carcinoma. The parameters considered are the number of platelets and their aggregability, prothrombin and partial thromboplastin times, plasma fibrinogen concentration and tumor cell procoagulant activity. Slight variations are caused by drug treatment in tumor-bearing mice as compared with untreated tumor-bearing controls; the pattern of effects of the selective antimetastatic agents does not differ from that of the reference cytotoxic compound used, cyclophosphamide. These data thus indicate that the effects on hemostasis of the drugs examined can contribute only marginally to their antimetastatic action, since more pronounced effects on hemostasis have been shown to be required to significantly affect metastasis formation.
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PMID:Hemostasis and mechanism of action of selective antimetastatic drugs in mice bearing Lewis lung carcinoma. 654 Jan 95

The effects of Russell's viper venom on blood coagulation, platelets and the fibrinolytic enzyme system were studied in rabbits after injecting repeated doses of 0.05 MLD of the venom. Thrombocytopenia was the earliest change to appear. It was followed by rise in serum fibrinogen degradation products and prolongation of prothrombin time, activated partial thromboplastin time and thrombin time indicating a progressive consumption coagulopathy and activation of fibrinolysis. Red blood cell morphology was unchanged during the first three weeks; whereas the fragmentation appeared after the fourth week and it increased in severity with further envenomations, i.e. when chronic DIC was established.
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PMID:Effects of prolonged poisoning by Russell's viper venom on blood coagulation, platelets and fibrinolysis. 673 75


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