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:3.4.21.7 (plasmin)
9,023 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Tissue plasminogen activator (tPA) has a critical role in fibrinolysis, converting plasminogen into active protease plasmin. Because intravenous tPA has only limited effectiveness as acute stroke therapy, enhancement of endogenous tPA represents a potential alternative to stroke treatment. Adenoviral-mediated gene transfer was used to enhance production of tPA in bovine brain capillary endothelial cells (BEC). Antigen and activity levels of tPA and plasminogen activator inhibitor-1 (PAI-1) in media from BEC infected with AdCMVtPA were analyzed. Conditioned media were analyzed for thrombomodulin, the integral membrane antithrombotic molecule that co-activates protein C. BEC infected with AdCMVtPA demonstrated enhanced expression of tPA antigen (40.2 +/- 0.4 ng/mL vs 1.1 +/- 1.5 ng/mL [p<0.001] and 0.3 +/- 0.5 ng/mL [p<0.0001], respectively) and increased tPA enzymatic activity (27.4 +/- 5.7 IU/mL vs 8.3 +/- 1.7 IU/mL [p<0.05] and 13.3 +/- 3.2 IU/mL [p<0.05], respectively) compared to BEC infected with the control adenovirus (Adl327) or uninfected BEC. There was a moderate increase in PAI-1 protein 4 days after transfection with AdCMVtPA, and the integral membrane protein thrombomodulin was released into media by transfected BEC. These results demonstrate that adenoviral-mediated delivery in vitro of the human tPA gene resulted in high levels of expression of tPA in BEC. Transient overexpression of tPA by gene transfer might be a useful strategy to protect against thrombotic occlusion during the period of risk of acute stroke.
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PMID:Adenoviral-mediated transfer of tissue plasminogen activator gene into brain capillary endothelial cells in vitro. 1157 Jun 62

DIC is a life-threatening complication of several disease states. It is characterized by systemic activation of the hemostasis system. In many instances the release of tissue factor (TF) from endothelial cells or other circulating cells triggers the system. Initially, the increased activation can be compensated for by the natural inhibitor systems, a state referred to as compensated DIC. As the trigger persists, inhibitors will be consumed leading to more coagulation. In this process many clotting factors, most notably fibrinogen and platelets are consumed, resulting eventually in a complete breakdown of the hemostasis system. This results in a profuse and diffuse bleeding tendency or decompensated DIC. The term consumptive coagulopathy denotes this process. Of crucial importance is the fate of fibrin that is formed from fibrinogen by thrombin. If the fibrinolytic system is insufficiently activated, fibrin will be deposited in the microcirculation leading to MODS. This will not occur if the fibrinolytic system is fully activated. The clinical suspicion of DIC must be confirmed by laboratory tests and decreasing fibrinogen levels and platelet counts support the diagnosis. The determination of D-dimer, fibrin(ogen) split products (FSP) and soluble fibrin monomer (FM) further support the diagnosis. FM suggest the presence of thrombin, FSP the generation of plasmin, and D-dimer, both thrombin and plasmin. While the tests are not specific for DIC, they can be helpful, in the proper clinical setting, to diagnose decompensated or acute DIC. The tests are not useful for the diagnosis of compensated DIC, except for D-dimer, FSP, and FM if elevated. Compensated DIC can be diagnosed by molecular markers of in vivo hemostasis activation, such as thrombin-antithrombin (TAT) complexes, prothrombin fragment 1 + 2 (F 1 + 2), or plasmin-antiplasmin (PAP) complexes. For the treatment of DIC it is imperative to remove the triggering underlying disease. The consumption of coagulation constituents can be corrected by cryoprecipitate, platelet concentrates, and fresh frozen plasma, if needed. This may reduce the bleeding tendency. Arrest of the activated hemostasis system by heparins, either subcutaneous in low doses or intravenous in therapeutic doses, is only recommended in patients with compensated DIC. If the patient bleeds, heparins should not be given. The administration of concentrates of natural anticoagulants, i.e., antithrombin, protein C, or tissue factor pathway inhibitor are safer than heparins since they do not exacerbate the bleeding tendency. These concentrates were found to be very effective in animal models of DIC; human experience is still limited. Generally, the earlier treatment is initiated, the better the patient's prognosis.
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PMID:Disseminated intravascular coagulation (DIC). 1158 11

We sought to assess the longitudinal stability of risk factors for atherosclerosis and thrombosis. including several coagulation. fibrinolysis, and inflammation factors, in frozen plasma samples stored at -70 degrees C for months or years. We reviewed data collected on 29 different control pools over periods ranging from 7 to 59 months for two functional assays (factor VII and fibrinogen) and seven antigen measurements (C-reactive protein. D-dimer, plasmin-alpha2-antiplasmin complex, plasminogen activator inhibitor-1, protein C, protein S, and tissue plasminogen activator), totaling more than 15,000 data points. Screening of the data using least squares regression revealed only sporadic associations between monthly means and time, with no consistent trends. Analysis by repeated measures and summary measure methods revealed no evidence of sample degradation over time for the factors studied. Our finding of longitudinal stability in the biochemical properties of frozen plasma strengthens the presumption of sample stability on which molecular epidemiologic studies are based.
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PMID:Longitudinal stability of coagulation, fibrinolysis, and inflammation factors in stored plasma samples. 1177 19

Pigs are often used as animal models in research on blood coagulation and fibrinolysis. The usefulness of the assays applied within this field, and the knowledge of reference intervals are therefore essential and of utmost importance. In the study reported here, we investigated the applicability of commercial human coagulation and fibrinolysis assays for use with porcine plasma. In total, 22 functional and immunologic assays were applied to plasma obtained from domestic pigs, and the following blood coagulation and fibrinolysis variables were measured: prothrombin time, activated partial thromboplastin time, tissue factor, tissue factor pathway inhibitor, factor VII, protein C, protein S, prothrombin fragment 1+2, antithrombin, thrombin-antithrombin complexes, fibrinogen, soluble fibrin, urokinase-type plasminogen activator, plasmin inhibitor, plasminogen activator inhibitor 1, and D-dimer. We found that 11 of 12 functional assays, but only 3 of 10 immunoassays, were applicable to porcine plasma, and we determined the normal range of these variables. We conclude that human functional assays are useful in porcine plasma, whereas only a few immunologic assays can be used. However, precautions must be taken in interpretation of the results and in extrapolation toward human results because possible differences between porcine and human values can be due to species variations and/or methodologic errors.
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PMID:Usefulness of human coagulation and fibrinolysis assays in domestic pigs. 1190 Apr 11

A condition of oxidative stress, due to perturbation of oxidant/antioxidant balance, has been suggested to play a role not only in the pathogenesis of human immunodeficiency virus (HIV) infection, but also in the promotion of a thrombophilic condition. Because various hemostatic dysfunctions usually considered as risk factors for thrombotic events were reported in HIV infection, this study was undertaken to investigate whether the oxidative phenomenon could promote a prothrombotic state in such condition. Erythrocyte glutathione peroxidase (GSH-Px), the major free-radical scavenger enzyme, and serum tumor necrosis factor-alpha (TNF-alpha) were evaluated in 33 consecutive HIV-infected out-patients and 35 matched HIV-negative healthy controls at a distance of any acute episode. Thrombin generation was explored by measuring the plasma levels of prothrombin fragment 1 + 2 (F1 + 2), whereas fibrin degradation products (D-dimer) and plasminogen activator inhibitor (PAI-1) activity were evaluated as indices of plasmin activity and fibrinolytic derangement. The anticoagulant pathway was investigated by measuring the plasma levels of antithrombin and protein C. Erythrocyte GSH-Px activity and serum TNF-alpha were significantly higher in HIV-infected patients when compared to controls. F1 + 2, D-dimer, and PAI-1 activity were increased in HIV-infected patients by comparison with controls. Normal antithrombin, but decreased protein C, was instead detected in HIV-infected patients. In the latter patients, serum TNF-alpha negatively correlated with both erythrocyte GSH-Px activity and plasma D-dimer. On the other hand, a positive correlation was shown between F1 + 2 and D-dimer and between D-dimer and GSH-Px activity. Furthermore, a trend toward increasing levels of GSH-Px with increasing PAI-1 activity was reported. These findings suggest a relationship between erythrocyte oxidative stress and the hypercoagulable condition during HIV infection.
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PMID:Increased erythrocyte glutathione peroxidase activity and serum tumor necrosis factor-alpha in HIV-infected patients: relationship to on-going prothrombotic state. 1198 8

A randomized prospective double-blind trial was performed to compare the safety and efficacy of human activated protein C (APC) and unfractionated heparin for the treatment of disseminated intravascular coagulation (DIC). One hundred thirty-two patients with DIC were enrolled in this study: 63 patients received APC (12.5 U [2.5 microg]/kg body wt per hour) and 69 patients received heparin (8 U/kg body wt per hour) by intravenous infusion for 6 days. Forty-nine APC-treated patients and 55 heparin-treated patients were evaluated for efficacy, and 52 APC-treated patients and 55 heparin-treated patients were evaluated for safety. The 2 groups were similar with respect to sex, age, body weight, underlying diseases, and coagulation/fibrinolysis parameters before treatment. Aggravation of bleeding was seen after treatment in 8 patients receiving heparin, but in none of the patients receiving APC. The number of patients who showed alleviation of bleeding was significantly higher in the APC group than the heparin group (P = .009). The effects on DIC-related organ dysfunction were not significantly different between the 2 groups. Fibrinogen-fibrin degradation products, D-dimer, thrombin-antithrombin complex (TAT), and plasmin-plasmin inhibitor complex (PIC) were all significantly decreased by treatment in both groups. Fibrinogen, protein C, and antithrombin were significantly increased in the APC group, whereas only protein C was significantly increased in the heparin group. Platelet count in the nonleukemic group was significantly increased in those patients receiving APC but not increased in those patients receiving heparin. Improvement of coagulation/fibrinolysis was assessed by scoring 4 parameters (soluble fibrin monomers, D-dimer, TAT, and PIC), and the results indicated that the APC group showed significantly greater improvement than the heparin group (P = .046). There was, however, no significant difference in the rate of complete recovery from DIC between the 2 groups. The rate of death from any cause within 28 days after treatment was 20.4% in the APC group, significantly lower than the 40% death rate observed in the heparin group (P < .05). There were no severe adverse events in either group. These results suggest that APC in a relatively small dosage can improve DIC more efficiently than can heparin, without increasing bleeding, and may be a better alternative.
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PMID:A comparative double-blind randomized trial of activated protein C and unfractionated heparin in the treatment of disseminated intravascular coagulation. 1209 57

Patients on continuous ambulatory peritoneal dialysis (CAPD) often have abnormalities of lipid metabolism or coagulation and fibrinolysis, these patients may thus be more susceptible to atherosclerosis than those on hemodialysis. It has been reported that hypercoagulability and hyperfibrinolysis are correlated with abnormalities of lipid metabolism. Therefore, we investigated the effect of a decrease in lipids on the coagulation and fibrinolysis system in CAPD patients with hyperlipidemia who received lipid-lowering therapy. The patients included 5 men and 13 women, with a mean age of 52.5 years. Pravastatin sodium (10 mg/day) and ethyl icosapentate (1800 mg/day) were administered concomitantly for 8 weeks. Lipid levels and coagulation/fibrinolysis parameters were measured before and after therapy. The patients were divided into two groups depending on their response to therapy: responders showed a decrease in total cholesterol or triglycerides by at least 20% and non-responders showed less improvement. In the responders, the levels of protein C, tissue plasminogen activator/plasminogen activator inhibitor-I complex, factor XIII, alpha2-plasmin inhibitor, and D-dimer were significantly lower after therapy than before therapy. Protein C, factor XIII, and alpha2-plasmin inhibitor were also significantly decreased after therapy in non-responders, but the extent of the decrease was smaller. The plasminogen level was significantly increased after therapy in non-responders. These findings suggest that a decrease in lipid levels and/or some other action by lipid-lowering agents may correct abnormalities of coagulation and fibrinolysis in CAPD patients.
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PMID:Lipid-lowering therapy and coagulation/fibrinolysis parameters in patients on peritoneal dialysis. 1211 34

Hemostatic abnormalities in 26 patients following bone marrow transplantation (BMT) were examined. In the event-free survival group, the plasma levels of antithrombin (AT) and protein C (PC) were significantly decreased 1 and 2 weeks after BMT, and the plasma levels of thrombomodulin (TM) and tissue plasminogen activator-plasminogen activator inhibitor-1 complex (tPA-PAI-I complex) were significantly increased from 4 weeks to 13 weeks after BMT. Excepting AT, there was no significant difference in hemostatic parameters before BMT among the event-free survival, 6-month survival, and death within 6 months groups. On day 0 following BMT, only plasma AT levels were significantly lower in the 6-month survival group than in the death within 6 months group. From 1 to 3 weeks after BMT, plasma levels of AT or PC were significantly lower in the death within 6 months group than in the 6-month survival group. From 1 to 5 weeks after BMT, the plasma levels of TM and tissue type plasminogen activator-plasminogen activator inhibitor-I complex (tPA-PAI-I complex) were significantly higher in the 6-month survival group than in the death within 6 months group. From 1 to 13 weeks after BMT, the plasma levels of D-dimer or soluble fibrin monomer (SFM) were significantly higher in the death within 6 months group than in the 6-month survival group. There was no remarkable difference in plasma levels of thrombin-antithrombin comlex or plasmin-plasmin inhibitor complex following BMT between these groups of patients. These findings suggest that the decrease in the plasma AT or PC level reflects early occurrence of complications of prognostic significance and that the increase in vascular endothelial cell markers such as plasma levels of TM or tPA-PAI-I complex reflects occurrence of complications during the middle course of BMT. Plasma levels of D-dimer and SFM may be useful markers for predicting complications associated with poor prognosis after BMT.
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PMID:Hemostatic abnormalities following bone marrow transplantation. 1212 Oct 52

Thromboembolic complications are often seen in patients with nephrotic syndrome. Markers of endothelial cell injury [thrombomodulin, intracellular adhesion molecule, vascular cell adhesion molecule, thrombin activatable fibrinolysis inhibitor (TAFI), protein Z, vascular endothelial growth factor, markers of thrombin and plasmin generation] were studied in 22 patients with nephrotic syndrome. All these parameters studied, except protein Z and D-dimers, were significantly higher in patients with nephrotic syndrome, whereas protein Z was significantly lower when compared with the healthy volunteers. None of the endothelial cell markers (thrombomodulin, P-selectin, E-selectin, intracellular adhesion molecule, vascular cell adhesion molecule), thrombin and plasmin generation markers (thrombin-antithrombin complexes, prothrombin fragments 1 + 2, plasmin-antiplasmin complexes, D-dimers), protein C, protein Z, vascular endothelial growth factor, and TAFI concentration and activity were directly correlated with the level of proteinuria, albumin, cholesterol, triglycerides or creatinine, except significant positive correlations between TAFI activity and serum creatinine, E-selectin and albumin as well as negative correlations between plasmin-antiplasmin complexes and proteinuria. In these patients, there is evidence of endothelial cell injury and probably secondary activation of the coagulation cascade. Elevated circulating TAFI antigen and activity might be a new link in the pathogenesis of impaired fibrinolysis and the progression of atherosclerosis in nephrotic syndrome. Protein Z deficiency might also contribute to the enhanced risk of thromboembolic complications in nephrotic syndrome.
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PMID:Markers of endothelial cell injury and thrombin activatable fibrinolysis inhibitor in nephrotic syndrome. 1243 47

The serine proteases, cofactors and cell-receptor molecules that comprise the haemostatic mechanism are highly conserved modular proteins that have evolved to participate in biochemical reactions in blood coagulation, anticoagulation and fibrinolysis. Blood coagulation is initiated by exposure of tissue factor, which forms a complex with factor VIIa and factor X, which results in the generation of small quantities of thrombin and is rapidly shutdown by the tissue factor pathway inhibitor. The generation of these small quantities of thrombin then activates factor XI, resulting in a sequence of events that lead to the activation of factor IX, factor X and prothrombin. Sufficient thrombin is generated to effect normal haemostasis by converting fibrinogen into fibrin. The anticoagulant pathways that regulate blood coagulation include the protein C anticoagulant mechanism, the serine protease inhibitors in plasma, and the Kunitz-like inhibitors, tissue factor pathway inhibitor and protease nexin 2. Finally, the fibrinolytic mechanism that comprises the activation of plasminogen into plasmin prevents excessive fibrin accumulation by promoting local dissolution of thrombi and promoting wound healing by reestablishment of blood flow.
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PMID:Proteases in blood clotting. 1246 64


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