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)

The effect of Norplant subdermal implants on 22 different hemostatic variables was determined in 100 women attending the Fertility Control Clinic of the Singapore National University Hospital before and after 6 and 12 months of use. The factors analyzed were: hematocrit, hemoglobin (Hb), prothrombin time (PT), activated partial thromboplastin time (APTT), platelet count, fibrinogen, coagulation factor II, Factor V,Factor VII, Factor VIII, Factor VIIIR:Ag, Factor X, plasminogen activator, FDP, plasminogen (imm), antithrombin III (functional), antithrombin (antigen), protein C, alpha2-antiplasmin, alpha2-macroglobulin, alpha2-antitrypsin, platelet count, platelet aggregation (ADP), and platelet aggregation (collagen). The factors that differed significantly after 12 months were: Hb,PT,APTT, Factors II,V,VII, and VIIIR:Ag, Plasminogen (imm), antithrombin III(antigen), alpha2-antiplasmin, platelet count, and platelet aggregation. Most of these differences, while significant, were still within the normal range, except for PT,APTT, and platelet count. The subjects were considered to be in an enhanced risk for hypercoagulation and thrombosis.
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PMID:The effects of Norplant-2 rods on clinical chemistry in Singaporean acceptors after 1 year of use: haemostatic changes. 314 69

The effect of high and low-dose oral contraceptives (OCs) on the fibrinolytic system remains controversial, although disturbances in this system are associated with the development of venous thrombosis. It has been suggested that this may be due to either a decreased synthesis of vessel wall tissue plasminogen activator (t-PA) or a defective release of t-PA from the vessel wall. Defective fibrinolysis can also be due to increased concentration of tissue plasminogen activitor inhibitor (PAI-I). This studied utilized new and improved methods for t-PA and PAI-I measurements in plasma to: study basal fibrinolytic activity, basal t-PA antigen concentration, and PAI-I in plasma from teenagers to assess whether these parameters are age-dependent; 2) evaluate the influence of low-dose OCs on the fibrinolytic components; and 3) study possible variations in some coagulation factors. Plasma were obtained from 20 healthy female adolescents (mean age 16 years), 17 health adult women (mean age 32 years) and 35 healthy adult males (mean age 34 years). Basal t-PA antigen concentrations plasma were highly age dependent, with higher values with increasing age. The fibrinolytic capacity was also lower in the younger women, while PAI-I levels were higher. This finding suggests a need for age- and sex-matched controls in studies of the components of fibrinolysis in plasma. 4 months of OC use did not affect coagulation parameters, factor VIII activity, AT III, Protein C, or platelet counts. However, fibrinolytic activity in plasma after venous occlusion (15 minutes) increased significantly in teenagers who used OCs for 4 months. This finding was explained by significantly decreased PAI levels and increased t-PA antigen release from the vessel wall after venous occlusion.
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PMID:Age dependence of blood fibrinolytic components and the effects of low-dose oral contraceptives on coagulation and fibrinolysis in teenagers. 314 43

Two short-lived vitamin K-dependent factors, factor VII and protein C, were measured by both functional and antigenic techniques in 3 hematological conditions known for their risk of hepatotoxicity: Following use of asparaginase and bisantrene, and patients at high risk of hepatic veno-occlusive disease after allogenic bone marrow transplantation for relapse of acute leukemia of accelerated phase of evoluted chronic myelogenic leukemia. In these 3 conditions functionally measured levels of protein C and factor VII, and antigenically measured levels of both these factors proved to be early markers of incipient hepatic involvement. These tests were easy to use routinely were reproducible, and proved to be predictive of veno-occlusive disease in grafted patients at the preconditioning stage. In the follow-up of bone marrow grafted patients plasma markers of endothelial function (von Willebrand's factor, tissue type plasminogen activator, and plasma activity of angiotensin converting enzyme) were significantly altered at the time of overdose with cyclosporin A, probably due to a drug-induced in vivo lesion of the endothelium. In the search for cytoprotective drugs for the prevention of veno-occlusive disease in bone marrow grafted patients prostaglandin E1 (PGE1) was given prior to and for at least 4 weeks after transplantation and proved to be effective by biological criteria (the level of protein C mainly). This deserves further study in a prospective clinical trial of the potential usefulness of PGE1 in preventing liver veno-occlusive disease in bone marrow grafted patients.
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PMID:[Hemostasis tests as markers of hepatic and endothelial toxicity in chemotherapy]. 329 Aug 34

Three patients with karyotype XYY who had presented with deep vein thrombosis and leg ulcers (plus pulmonary embolism in two of them) were investigated for: (1) androgens (plasma testosterone measurement, testosterone oestradiol binding globulin (TeBG) assay, GnRH 50 micrograms test), and (2) haemostasis by fibrinolysis tests (euglobulin lysis time and area, antigenic plasminogen activator assay before and after 10 min venostasis). Full evaluation of haemostasis failed to demonstrate the presence of circulating anticoagulant or of antithrombin III, protein C and protein S deficiencies. One patient had neither hormonal nor fibrinolytic abnormality. The other two patients shared some clinical features with male hypogonadism (gynoid morphotype in both, hypotrophy of the testes in one, gynaecomastia in the other). They also had hormonal disorders ("over-response" to the GnRH test in one case, elevated TeGB in the other case) and abnormalities of fibrinolysis (poor response to venostasis, high baseline level of plasminogen activator). Response to venostasis became normal after 3 months of treatment with percutaneous dihydrosterone 125 mg per day in the two patients with initially poor response. The mechanism of venous pathology in XYY subjects is discussed. A genetic defect not involving the fibrinolysis system is possible since fibrinolysis was normal in one patient; however, abnormal fibrinolysis may have been responsible for the venous pathology in the other 2 patients. The role played by abnormalities of fibrinolysis in the pathogenesis of deep vein thrombosis and leg ulcers is recalled, and the possible implication of these abnormalities in patients with XYY karyotype is emphasized.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:[Post-phlebitic leg ulcers and XYY karyotype: fibrinolysis and androgenic function tests. Apropos of 3 cases]. 343 47

Some molecular defects of components of the coagulation or fibrinolytic system are associated with thromboembolism. One possibility is that physiologic inhibitors of the coagulation system have an abnormal function e.g. protein C, protein S, antithrombin III and cofactor II of heparin. Also a hindered activation of the fibrinolytic system may predispose to thrombosis; the impaired activation may be due to deficient synthesis and/or release of tissue-plasminogen activator, an increased level of its inhibitor or a functional defect of the plasminogen molecule. A few cases of congenital dysfibrinogenemia have been described in which the functional defects of the molecule are held responsible for recurrent thrombosis. An acquired thrombotic disorder is due to the presence of immunoglobulins which prolongs phospholipid-dependent coagulation by binding to epitopes of some phospholipids. This so-called lupus anticoagulant was originally described in patients with systemic lupus erythematosus but is a misnomer as it is more frequently encountered in patients without lupus.
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PMID:[Molecular defects of coagulation factors and of the fibrinolytic system associated with thromboembolism]. 354 55

Lysis of clots prepared from native or citrated whole blood as measured by release of 125I fibrinogen degradation products was 10% or less at 20 hours. Lysis of these clots was accelerated by activated protein C in a dose-dependent manner (0.1 to 20 micrograms/ml) from less than 10% to 60-80% at 20 hours. Lysis of clots prepared from native or citrated platelet poor plasma across the same concentration range of activated protein C was less than 15%. Gla-domain-less activated protein C was equally effective in accelerating clot lysis whereas DIP-activated protein C or factor Xa did not accelerate clot lysis. This suggested that this action of activated protein C was enzymatic and this this action was limited to protein C among the vitamin K dependent proteins. The unresponsiveness of platelet poor plasma to activated protein C was completely restored to that of whole blood by addition of mononuclear leukocytes. Addition of red corpuscles or platelets alone had no effect on this response, while addition of polymorphonuclear leukocytes partially restored this response. Addition of metabolic inhibitors 2-deoxyglucose and oligomycin inhibited the response of whole blood and of plasma-mononuclear leukocytes to activated protein C. Reconstitution studies of platelet poor plasma made deficient in plasminogen activator and plasminogen showed that accelerated clot lysis produced by mononuclear leukocytes and activated protein C required the presence of plasminogen. We concluded, therefore, that activated protein C accelerates whole blood or plasma-leukocyte clot lysis by modulating activation of the plasminogen system by metabolically active leukocytes.
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PMID:Whole blood clot lysis: in vitro modulation by activated protein C. 383 29

We studied a Spanish family in which one of the female members presented recurrent thrombophlebitis in both legs after three different deliveries. Biological and antigenic activity of protein C was decreased (35% and 42% respectively). Reduced protein C levels were also observed in 6 other family members. Administration of danazol (600 mg/day) in two patients with protein C deficiency elevated this protein and discontinuation of the drug resulted in a reduction of protein C to pretreatment values. The proposita showed a normal fibrinolytic activity and infusion of DDAVP produced a similar response of FVIII/VWF and plasminogen activator to those observed in healthy subjects.
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PMID:Protein C deficiency--response to danazol and DDAVP. 384 Feb 87

In separate experiments, antibodies to plasminogen, factor X and protein C were applied to microtitre trays as commonly used in enzyme-linked immunoassays. After incubation with dilute normal human plasma as a source of the corresponding proenzyme antigen, the wells were exposed to dilutions of various snake venoms. After thorough washing, the microtitre tray wells were tested overnight with chromogenic tripeptide substrates known to be relatively specific for the activated forms of the above factors, i.e., plasmin, factor Xa and activated protein C. The immunochromometric assay described detected two new activators of protein C in Agkistrodon piscivorus and Agkistrodon contortrix venoms and a new factor X activator in Agkistrodon rhodostoma venom. Gel filtration of the latter venom indicated that the factor X activator eluted with high molecular weight, was clearly distinct from the peak fibrinogen clotting activity (Ancrod) and appeared to have no procoagulant activity. Although several Bothrops venoms appeared to contain plasminogen activator by this technique, the observed strong chromogenic activity was observed in microtitre wells independently of plasminogen and represented nonspecific amidase activity.
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PMID:Detection of specific proenzyme activators in snake venoms by a new immunoabsorbant-chromogenic substrate method. 384 Oct 12

The effects of bovine activated protein C (APC) on the fibrinolytic activity of cultured bovine aortic endothelial cells were investigated. Confluent monolayers were incubated with purified APC under various conditions and changes in total fibrinolytic activity and in the level of plasminogen activator and plasminogen activator inhibitor (antiactivator) were monitored. The addition of APC to the cells in the absence of other blood or plasma components led to a rapid, dose-dependent increase of fibrinolytic activity both in the media and in cellular extracts. For example, 3.4 micrograms of APC per ml resulted in a 15-fold increase of fibrinolytic activity in the medium within 1 hour. The enhanced fibrinolytic activity reflected increases in both the urokinase-related and tissue-type plasminogen activators produced by these cells. Interestingly, treatment of cells with APC also caused a rapid, dose-dependent decrease in antiactivator activity. Diisopropyl fluorophosphate-inactivated APC did not decrease antiactivator or increase plasminogen activator. Although a small but significant direct (i.e., cell-independent) effect of APC on both fibrinolytic activity and antiactivator activity could be demonstrated, the major portion of these changes appeared to be cell-mediated. These observations indicate that the fibrinolytic potential of cultured endothelial cells is increased by APC and that the enzyme active site is essential for this change. Moreover, the results suggest that one of the primary mechanisms for this stimulation of endothelial cell fibrinolytic activity involves an APC-mediated decrease in antiactivator.
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PMID:Activated protein C stimulates the fibrinolytic activity of cultured endothelial cells and decreases antiactivator activity. 387 46

Utilizing modified immunochemical methods (ELISA and radioimmunoassay) tissue plasminogen activator, B beta 15-42 RPs and protein C antigen levels were measured in man and a subhuman primate model after subcutaneous and intravenous administration of various low molecular weight heparin fractions. A wide scatter in the data was observed in the t-PA and B beta 15-42 RP levels; however, statistical analysis of the data revealed that certain low molecular weight heparin fractions increased the levels of these endogenous markers of fibrinolysis. No significant alteration in the protein C levels was noted at any time; however, a wide scatter in these data was also evident. The profibrinolytic actions of low molecular weight heparin fractions may be related to the release of t-PA, which is easily measured in plasma. Since it has strong affinity for endogenous sites (thrombus, surface), wide scatter in the data may occur. Physical exercise may also increase the levels. Most of the results reported in our studies represent data on blood samples that were obtained using the simple venipuncture method. We also find that the intravenous administration of the low molecular weight heparin fractions also caused a shortening of the ELT. Since the low molecular weight heparin fractions are heterogeneous in nature, the profibrinolytic actions may be related to one or more of these constituent fragments. Thus, the molecular identity of the profibrinolytic component of low molecular weight fractions remains unknown at this time. Also unknown is if there is a relationship between this effect and anticoagulant activity.
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PMID:Studies on the profibrinolytic actions of heparin and its fractions. 387 99


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