Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P00750 (PLA)
 16,800 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Long-term treatment of rabbits with beta-sitosterol (40 mg/kg over 3 months) caused an increased fibrinolytic activity in blood, an increased fibrinolytic capacity and an enhanced plasminogen activator activity in tissue of lungs and kidneys. The 3-months lasting beta-sitosterol administration did not influence the content of plasminogen activator inhibitor, plasminogen, alpha 2-antiplasmin, antithrombin III and fibrinogen.
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PMID:Influence of beta-sitosterol on the fibrinolytic potential in rabbits. 245 19

Orthotopic liver transplantation is frequently associated with hyperfibrinolysis, the origin and clinical relevance of which is largely unknown. In 20 orthotopic liver transplantations, we studied the occurrence and systemic effects of hyperfibrinolysis. Severe fibrinolysis was defined to be present when the euglobulin-clot lysis time and the whole-blood-clot lysis time, as measured by thrombelastography, were shorter than 60 and 90 min, respectively, at some time during the operation. Based on these criteria, 7 patients had minimal fibrinolysis (group I), and 13 patients had severe fibrinolysis (group II). In group II a gradual increase of tissue-type plasminogen activator (t-PA) activity was seen during the anhepatic stage, followed by an "explosive" increase immediately after graft reperfusion (P = 0.0004, compared with group I), and a reduction of plasminogen activator inhibitor (PAI) activity. Plasma degradation products of fibrinogen and fibrin increased parallel to t-PA activity, and levels were significantly higher at 45 min after graft reperfusion in group II compared with group I (P less than 0.04). Thrombin-antithrombin III complexes showed an identical steady increase in both groups, indicating that increased t-PA activity was not related to thrombin formation. A combination of increased endothelial release and reduced hepatic clearance may have caused the increased t-PA activity. The t-PA-associated destruction of fibrinogen and fibrin after graft reperfusion is consistent with the clinical signs of severe oozing often seen in this period. These observations may have important clinical implications for the treatment of bleeding in patients undergoing orthotopic liver transplantation.
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PMID:Systemic effects of tissue plasminogen activator-associated fibrinolysis and its relation to thrombin generation in orthotopic liver transplantation. 249 62

The activity of tissue plasminogen activator (t-PA) and urokinase-type plasminogen activator (u-PA) is stimulated by heparin. Heparin binds tightly to t-PA, u-PA, and plasminogen and decreases the usual stimulatory effect of fibrin on t-PA activity. In the present study we have found that low molecular weight heparin (LMW-heparin) preparations obtained by nitrous acid depolymerization or heparinase treatment of standard heparin have different properties with respect to their interaction with the fibrinolytic system. LMW-heparin prepared by either method does not stimulate plasmin formation by t-PA. However, these preparations of heparin still efficiently accelerate the inhibition of thrombin by antithrombin III. Binding data show that LMW-heparin does not bind t-PA and Glu-plasminogen and only binds very weakly to Lys-plasminogen. These results illustrate that it is possible to selectively destroy the fibrinolytic stimulating properties of heparin while leaving the classical anticoagulant characteristics intact.
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PMID:Anticoagulant low molecular weight heparin does not enhance the activation of plasminogen by tissue plasminogen activator. 250 19

Pharmacokinetics and systemic effects of recombinant tissue-type plasminogen activator (rt-PA) were determined during coronary thrombolysis in 12 acute myocardial infarction patients using a consecutive intravenous infusion regimen. Ten mg rt-PA were infused in 2 minutes resulting in a peak plasma concentration (mean +/- SD) of 3310 +/- 950 ng/ml, followed by 50 mg in 1 h and 30 mg in 1.5 h yielding steady state plasma levels of 2210 +/- 470 ng/ml and 930 +/- 200 ng/ml, respectively. All patients received intravenous heparin. Total clearance of rt-PA was 380 +/- 74 ml/min, t1/2 alpha was 3.6 +/- 0.9 min and t1/2 beta was 16 +/- 5.4 min. After 90 min, in plasma samples containing anti-rt-PA-IgG to inhibit in vitro effects, fibrinogen was decreased to 54%, plasminogen to 52%, alpha 2-antiplasmin to 25%, alpha 2-macroglobulin to 90% and antithrombin III to 85% of initial values. Coagulation times were prolonged and fibrin D-dimer concentrations increased from 0.40 to 2.7 micrograms/ml. It is concluded that pharmacokinetics of rt-PA show low interpatient variability and that its short mean residence time in plasma allows precise control of therapy. Apart from its moderate effect on the haemostatic system, rt-PA appears to lyse a fibrin pool in addition to the coronary thrombus.
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PMID:Pharmacokinetics and haemostatic status during consecutive infusions of recombinant tissue-type plasminogen activator in patients with acute myocardial infarction. 250 58

The profile of blood coagulation and fibrinolysis was studied in detail in eight patients with acute thrombotic thrombocytopenic purpura (TTP). In the majority of the patients, fibrinogen, factor XIII, antithrombin III, alpha 2-plasmin inhibitor, plasminogen, and alpha 2-macroglobulin were normal, whereas FDP, plasmin-alpha 2-plasmin inhibitor complex, and tissue-type plasminogen activator antigen were marginally or moderately elevated. Low fibronectin values were observed in four patients. Protein C and C4b-binding protein were nearly normal, whereas total protein S and free protein S were reduced in five and six patients, respectively. A positive correlation was found between total protein S and C4 and between free protein S and C3. von Willebrand factor antigen (vWf:Ag) and ristocetin cofactor (RCof) were either normal or elevated, but RCof/vWf:Ag ratio was decreased in seven patients. Crossed immunoelectrophoresis and sodium dodecyl sulfate (SDS)-agarose gel electrophoresis revealed that the large vWf multimers were either absent from or relatively decreased in all patients except one. In addition, one patient had unusually large vWf multimers, and a low-molecular-weight vWf fragment was apparently observed in three patients. These findings indicate that the intravascular generation of thrombin and plasmin was minimal in TTP and suggest that the alterations of the vWf molecule were caused not only by consumption through its participation in platelet thrombus formation but also by accelerated proteolysis. Low protein S values would be related to the immunological abnormalities underlying TTP.
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PMID:Coagulation studies in thrombotic thrombocytopenic purpura, with special reference to von Willebrand factor and protein S. 252 Dec 76

Patients with liver disease frequently have multiple hemostatic abnormalities. Coagulation and fibrinolytic factors and inhibitors may decrease as the result of impaired synthesis and/or enhanced catabolism. In order to assess the actual degree of activation of coagulation and fibrinolytic systems in liver disease, plasma levels of thrombin-antithrombin III complex (TAT) and plasmin-alpha 2-antiplasmin complex (PAP) were measured together with cross-linked fibrin derivatives (XDP), tissue-type plasminogen activator (t-PA), and plasminogen activator inhibitor (PAI-1) in 31 patients with liver disease (five patients with acute hepatitis, seven with chronic hepatitis, nine with liver cirrhosis, and ten with hepatocellular carcinoma). Mean plasma levels of TAT (mean 4.2 +/- SD 4.0 micrograms/L), PAP (0.7 +/- 0.7 mg/L), and XDP (374 +/- 518 micrograms/L) were significantly elevated in patients with liver disease as compared with normal subjects (TAT of 1.7 +/- 0.3 micrograms/L, PAP of 0.2 +/- 0.1 mg/L, and XDP of 30 +/- 14 micrograms/L; P less than 0.005). Plasma concentrations of t-PA and PAI-1 antigens were also elevated. When plotted by the disease categories, the magnitude of elevations of these parameters was variable among subgroups. Patients with acute hepatitis had considerably higher TAT levels. The mean PAP values were relatively high in chronic hepatitis and hepatocellular carcinoma, in which an elevation of the t-PA/PAI-1 ratio was observed. Although clearance of TAT and PAP should be evaluated in the future, these findings suggest that excessive amounts of thrombin and plasmin are actually generated in patients with liver disease.
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PMID:Thrombin and plasmin generation in patients with liver disease. 252 2

Diabetes mellitus (DM) is associated with an increased incidence of vascular complications. Abnormalities in the hemostatic system contribute at least in part to the development of vascular disease or atherosclerosis. In order to assess the actual degree of activation of the coagulation and fibrinolytic systems in diabetics, plasma levels of thrombin-antithrombin III complex (TAT) and plasmin-alpha 2-plasmin inhibitor complex (PAP) were measured together with tissue-type plasminogen activator (t-PA) and plasminogen activator inhibitor (PAI-1) in 18 patients with DM (three patients with type I DM and 15 with type II DM). Mean plasma levels of TAT (2.5 +/- SD 1.2 ng/mL) and PAP (0.9 +/- 1.2 micrograms/mL) were significantly elevated in diabetics as compared with healthy subjects (1.7 +/- 0.3 ng TAT and 0.2 +/- 0.1 micrograms PAP per mL of plasma; p = 0.009 and 0.02, respectively). Plasma antigen concentration of t-PA but not of PAI-1 was also elevated. No difference was found in the levels of these variables between type I and type II diabetics or between patients with and without retinopathy or nephropathy. These findings indicate that continuous activation of coagulation and fibrinolysis actually occurs in the majority of the patients with DM.
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PMID:Activation of blood coagulation and fibrinolysis in diabetes mellitus: evaluation by plasma levels of thrombin-antithrombin III complex and plasmin-alpha 2-plasmin inhibitor complex. 238 33

The effect of heparin as an anticoagulant was examined and the extent of fibrinolytic activity during cardiopulmonary bypass (CPB) was measured. Twenty patients undergoing valve replacement or aortocoronary bypass surgery were studied. Fibrinopeptide A (FPA) levels gradually became elevated as CPB proceeded, and antithrombin III (AT III) decreased during CPB. This indicates that despite the use of heparin, the coagulation system was activated, leading to fibrin formation in the microcirculation. On the other hand, fibrinopeptide B (FPB beta 15-42) also increased to four times the preoperative value at two hours on CPB. Intrinsic fibrinolytic activity, as determined by the activity of kaolin-activated euglobulin, was transiently increased only at the beginning of CPB. The C1 inactivator-resistant fibrinolytic activity and tissue plasminogen activator antigen (t-PA;Ag) increased sharply during CPB and reached maximum levels one hour after the start of CPB, indicating that enhanced fibrinolytic activity during CPB is predominantly of extrinsic origin as the result of t-PA release from the vascular walls. It is concluded from the above findings that thrombin activity continues during CPB. Enhanced fibrinolytic activity during CPB appears to be important because t-PA activates plasminogen predominantly where fibrin is formed, leading to dissolution of the microthrombi formed during CPB.
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PMID:Alterations in coagulation and fibrinolysis associated with cardiopulmonary bypass during open heart surgery. 253 75

Changes in the protein C-thrombomodulin (PC-TM) system in relation to other coagulofibrinolytic parameters were examined in 25 patients undergoing open heart surgery. Although all patients were given heparin, a decrease in antithrombin III (ATIII) and progressive increase in thrombin-ATIII complex (TAT) and fibrinopeptide A (FPA) levels were noted during cardiopulmonary bypass, which indicated that heparinization did not completely inhibit the formation of thrombin and its function. C1-inactivator (INA) resistant fibrinolytic activity increased markedly during CPB, in parallel with the change of tissue plasminogen activator antigen (t-PA;Ag), which indicates that fibrinolytic activity during CPB is mainly of extrinsic origin caused by t-PA. Protein C antigen (PC;Ag), protein S antigen (PS;Ag), and thrombomodulin antigen (TM;Ag) were all decreased significantly during CPB. This is considered to reflect the activation and consumption of the PC-TM system in response to generated thrombin. Furthermore, enhancement of the extrinsic fibrinolytic system is easily explained by the action of activated PC, which counteracts plasminogen activator inhibitor (PAI-1), to cause enhancement of t-PA activity.
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PMID:The role of the protein C-thrombomodulin system in physiologic anticoagulation during cardiopulmonary bypass. 255 68

An increase in plasma fibrinogen content and a decrease in level of antithrombin III in plasma with ageing may cause a thrombotic tendency in the elderly, although the main cause of thrombosis in the aged is atherosclerotic change seen in these subjects. Coagulability of blood is maintained in the so-called therapeutic range in aged patients receiving oral anticoagulant, as well as in younger subjects, however, it has been pointed out that there is an increasing risk of hemorrhage, especially of intracranial hemorrhage, with advancing age. Intracranial hemorrhage is not necessarily a rare complication of anti-platelet or thrombolytic therapy in the aged. Another hazard of aspirin therapy in the aged is the abrupt development of peptic ulcer. The authors administered 40 mg of aspirin per day to ten volunteers. In these subjects, platelets in the venous blood taken in a glass tube were strongly stimulated by coagulating whole blood in the tube for 60 minutes at 37 degrees C. Under this condition, arachidonic acid in platelets was converted to thromboxane B2, which is a stable metabolite of thromboxane A2 that causes platelet aggregation and vasoconstriction to accelerate thrombus formation. After ingestion of the minidose aspirin for one week, the concentration of thromboxane B2 in the serum (not in the plasma) of the volunteers decreased to 7% of the values determined before the administration of the drug, because of inhibition of cyclo-oxygenase in the platelets by aspirin. However, concentration of 6-keto-PGF1 alpha, which is a stable metabolite of prostacyclin that originates from arachidonic acid by cyclo-oxygenase in the vessel wall, did not markedly decrease after the treatment with aspi2+ t-PA and hybrid of t-PA and scu-PA in the aged are discussed. If antithrombotic therapy is always safe in the aged, it may be rational and economical to select subjects predisposed to thrombosis among patients with atherosclerosis. Determination of levels of fibrinogen, beta-thromboglobulin and/or thrombin-antithrombin III complex in plasma may be useful to predict thrombosis.
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PMID:[Antithrombotic drugs]. 267 54


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