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 response of components of the coagulation and fibrinolysis systems to infusion of DDAVP has been examined in patients undergoing elective surgery. In the DDAVP treated group there was a significant increase, compared to control, in plasminogen activator (by fibrin plates p less than 0.005, ECLT p less than 0.0125, by Student's t test) before operation. No difference between groups was seen by either methods in the activator levels in samples 24 h postoperation, whereas a significant drop (p less than 0.002) in protein C concentration was observed at this stage in the treated group. Levels of factor VIII components were significantly higher (p less than 0.005) than control at all stages of operation and a significant shortening (5 sec p less than 0.05) of the APTT was seen at all stages (apart from 24 h samples). DDAVP infusion therefore may exacerbate the hypercoagulable state observed in surgical patients without preventing the (post-operatively) fibrinolytic shutdown. Instead, infusion tends to produce fibrinolytic depletion at the key mid-operative stage.
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PMID:The influence of DDAVP infusion on the coagulation and fibrinolytic response to surgery. 308 64

Various parameters of the fibrinolytic system and antigenic and functional protein C and its inhibitor were studied during normal pregnancy and in patients with preeclampsia. The fast acting tissue-type plasminogen activator inhibitor level was found to increase progressively during normal pregnancy. This increase was more evident in cases of severe preeclampsia (p less than 0.05). No variations were observed in protein C levels in normal pregnancies but a reduction in protein C level was noted in patients with severe preeclampsia (p less than 0.01). In preeclampsia, the protein C inhibitor level was higher than in normal pregnancy; it was also higher in normal pregnancy when compared to the control group.
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PMID:Fibrinolytic activity and protein C in preeclampsia. 309 88

The mechanism by which activated protein C stimulates fibrinolysis was studied in a simple radiolabeled clot lysis assay system containing purified tissue-type plasminogen activator, bovine endothelial plasminogen activator inhibitor (PAI), plasminogen, 125I-fibrinogen and thrombin. Fibrinolysis was greatly enhanced by the addition of purified bovine activated protein C; however, in the absence of PAI, activated protein C did not stimulate clot lysis, thus implicating this inhibitor in the mechanism. In clot lysis assay systems containing washed human platelets as a source of PAI, bovine-activated protein C-dependent fibrinolysis was associated with a marked decrease in PAI activity as detected using reverse fibrin autography. Bovine-activated protein C also decreased PAI activity of whole blood and of serum. In contrast to the bovine molecule, human-activated protein C was much less profibrinolytic in these clot lysis assay systems and much less potent in causing the neutralization of PAI. This species specificity of activated protein C in clot lysis assays reflect the known in vivo profibrinolytic species specificity. When purified bovine-activated protein C was mixed with purified PAI, complex formation was demonstrated using immunoblotting techniques after polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulfate. These observations suggest that a major mechanism for bovine protein C-dependent fibrinolysis in in vitro clot lysis assays involves a direct neutralization of PAI by activated protein C.
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PMID:Mechanism of protein C-dependent clot lysis: role of plasminogen activator inhibitor. 309 99

The addition of thrombin (9 nM) to primary cultures of human endothelial cells induces a 6- to 7-fold increase in the rate of release of tissue plasminogen activator (tPA). Several other serine proteases which specifically interact with endothelial cells were also analyzed for their effect on tPA release. Gamma-thrombin, an autocatalytic product of alpha-thrombin, promoted tPA release but was less effective than alpha-thrombin. A maximum increase of 5.5-fold was observed, although a concentration of gamma-thrombin 20 times greater than alpha-thrombin was required. The response to Factor Xa was similar to alpha-thrombin, although the stimulation was significantly reduced by the addition of hirudin or DAPA suggesting that prothrombin activation was occurring. The simultaneous addition of prothrombin with Factor Xa resulted in enhanced tPA release equal to that observed with an equimolar concentration of active alpha-thrombin. Thus, under these conditions, Factor Xa-cell surface mediated activation of prothrombin can lead to a secondary effect resulting from cell-thrombin interaction. Activated protein C, which has been implicated as a profibrinolytic agent, was also tested. No change in tPA release occurred after the addition of up to 325 nM activated protein C in the presence or absence of proteins. Factor IXa and plasmin were also ineffective. The effect of thrombin on the endothelial cell derived plasminogen activator specific inhibitor was also studied. Thrombin produced a small but variable release of the inhibitor with an increase of less than twice that of non-thrombin treated controls.
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PMID:Specificity of the thrombin-induced release of tissue plasminogen activator from cultured human endothelial cells. 310 Dec 18

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

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


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