Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.4.21.68 (tissue plasminogen activator)
 11,311 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Changes in hemostatic factors after bone marrow transplantation (BMT), with or without thrombotic complications, have already been described. The endothelium seems to be actively involved in such processes. Over a period of 2 years we evaluated various hemostatic factors, associated or not with endothelial stimulation, in 44 patients with BMT (40 leukemias and 4 aplastic anemias). Factor VIII activity (VIII:C), von Willebrand factor antigen (vWF:Ag), tissue plasminogen activator antigen (tPA), plasminogen activator inhibitor activity (PAI-1), antithrombin III, protein C and protein S were assayed before and 1, 3, 6, 12, 18, and 24 months after BMT. Factor VIII:C, vWF and tPA were found to be significantly increased 1-6 months after BMT, returning to normal later. Patients with acute graft versus host disease, fever or cyclosporin treatment had significantly higher VIII:C, vWF and tPA. The increase in these factors implies lasting stimulation of their release and/or synthesis from endothelial cells that is enhanced by some complications of BMT. The degree and character of these changes could favor activation of thrombotic processes.
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PMID:[Activation of endothelium-dependent hemostatic factors following bone marrow transplantation]. 789 69

We attempted to determine if a hypercoagulability state exists in patients with polycythemia vera (PV) and essential thrombocythemia (ET). We studied the hematocrit level, platelet count, use of any antiaggregant drugs, thrombotic or bleeding accidents and plasma levels of antithrombin III, protein C, total protein S, free protein S, vWF:Ag (Von Willebrand's factor related antigen), thrombin-antithrombin complexes, D-dimer, fibrinolytic activity, tissue plasminogen activator, plasminogen and PAI-1 in 33 patients (19 with ET and 14 with PV). PAI-1 plasma concentration was significantly higher in, both ET and PV patients than in the control group, and were higher in those patients with previous thrombotic episodes than in asymptomatic patients or with previous bleeding episodes. Increasing age was associated to more thrombotic episodes while younger patients presented with more hemorrhagic complications. A linear correlation between platelet count and PAI-1 levels in PV patients (r = 0.44, p < 0.05) and ET patients (r = 0.30, p < 0.05) was found. Fibrinolytic activity in patients with ET was significantly decreased when compared to the control group. A hypofibrinolytic state could be an additional factor which could be used as a predictive index of the thrombotic or bleeding tendency in each patient.
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PMID:High plasma levels of plasminogen activator inhibitor 1 (PAI-1) in polycythemia vera and essential thrombocythemia are associated with thrombosis. 799 52

Commercial aurintricarboxylic acid (ATA) was separated into molecular-weight (MW) fractions of < 210 to > 25,000, using gel permeation chromatography. Fractions with MW > 1,300 effectively inhibited both botrocetin-induced vWF and bovine vWF binding to fixed human platelets. These activities decreased with a MW > 17,000. Platelet retention for a human in vitro was reduced by ATA at 150 microM, as was that for rats ex vivo at 3 mg/kg. ATA prolonged tail transection bleeding time in rats but had only a weak effect on buccal mucosal bleeding time in dogs. ATA had no effect on platelet count but markedly prolonged PTT. ATA at 10 mg/kg exhibited antithrombotic activity and caused a marked improvement in patency status following successful thrombolysis by t-PA in electrically and copper coil-induced thrombosis models. These results suggest that specific inhibitors of the vWF-GPIb interaction such as ATA may prove useful as antithrombotic agents.
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PMID:Inhibition by aurintricarboxylic acid of von Willebrand factor binding to platelet GPIb, platelet retention, and thrombus formation in vivo. 804 18

The influences of mechanical force during physical exercise on blood coagulation and fibrinolysis were investigated and the effects of sports equipment, especially shoes were also examined. As an experimental model, local mechanical vibration was applied to the palm of the hand. General coagulation parameters did not change, but fibrinolytic activity was elevated due to the tissue plasminogen activator (t-PA) released from vascular endothelial cells stimulated by vibration. The influence of mechanical stimulation by repeated side-jumping with bare feet was examined on the sole of the foot. As with t-PA, the von Willebrand Factor antigen (vWF:Ag) derived from vascular endothelial cells also tended to increase, but not as much as when wearing sports shoes. Sports shoes protected the blood vessels of the feet from damage by mechanical force during physical exercise. Changes in fibrinolytic activity and t-PA could be useful for assessing local mechanical stimulation during physical exercise and also as indexes for the development of new sports equipment and its improvement.
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PMID:Change in fibrinolytic activity as a parameter for assessing local mechanical stimulation during physical exercise. 807 27

In healthy subjects, intravenous infusion of the selective V2-vasopressin receptor agonist 1-desamino-8-D-arginine vasopressin (DDAVP, 400 ng/kg in 10 min) causes a marked increase in heart rate with a slight decrease in diastolic blood pressure. These haemodynamic responses are associated with increments in the plasma levels of renin, noradrenaline (NA), clotting factor VIII (FVIII:C), von Willebrand factor (vWF:ag), and tissue-type plasminogen activator (t-PA), and a fall in the plasma level of plasminogen activator inhibitor (PAI). None of these changes was observed in 3 patients with congenital nephrogenic diabetes insipidus (NDI), who had a genetic defect of the V2-receptor. Plasma AVP levels in these patients were normal or slightly elevated, which makes it unlikely that the lack of DDAVP responsiveness was caused by down-regulation of vasopressin V1-receptors. In one NDI patient, arginine vasopressin (AVP) was given in incremental doses (62.5-4000 pg/kg/min). The heart rate and blood pressure responses to AVP were normal, indicating the absence of a V1-receptor defect. The responses of vWF:ag and t-PA to venous occlusion in the patients with NDI were similar to those in 5 healthy volunteers, which indicates that in NDI the endothelial release of both vWF:ag and t-PA is normal. We conclude that DDAVP causes its effects on heart rate and blood pressure, and on the plasma levels of renin, noradrenaline, FVIII:C, vWF:ag, and t-PA through V2-receptor stimulation.
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PMID:1-Desamino-8-D-arginine vasopressin (DDAVP) in patients with congenital nephrogenic diabetes insipidus. 823 94

There is a need for viable small diameter vascular grafts, the luminal surface of which could be seeded by endothelial cells (ECs) to prevent thrombosis. In order to select candidates for EC seeding before implantation, the in vitro cytocompatibility of three different Pellethanes (polyetherurethanes) using human ECs was investigated. The methodology included two stages depending on either direct contact between cells and materials or contact between cells and material extracts, obtained under standardized conditions. By the latter method, we observed a cytotoxic effect on cell growth with 2363-55 D Pellethane extract at a 50% (v/v) concentration in the nutrient medium, likely provoked by leachables and correlated with the lowest levels of tPA, PAI1, and vWF antigens in the supernatants. By the former method, we studied EC attachment and growth. Morphology was studied by classical means and completed by scintigraphy and microautoradiography after 111Indium-labeling of the EC monolayer. Differentiation was determined by the release of vWF antigen and measurement of vWF activity (multimeric organization) after human thrombin stimulation. Despite an inhibition of proliferation for both 55 D and 75 D types (compared to the control), a functional monolayer of ECs was obtained on 75 D. Pellethane 75 D could be the best support for in vitro endothelization.
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PMID:Endothelial cell compatibility testing of three different Pellethanes. 826 99

In a recent prospective study of allogenic bone marrow transplantation we reported that decreases in factor VII and protein C were predictive markers for high risk of veno-occlusive disease (VOD). In order to determine the relative involvement of endothelial and hepatocyte injury in the genesis of VOD, 34 consecutive patients undergoing autologous bone marrow transplantation (BMT) were studied. Conditioning was performed by chemotherapy alone or associated with total body irradiation (TBI). Protein C and factor VII, the endothelial markers Von Willebrand factor (vWF and t-PA, fibrinogen and fibronectin were measured weekly before and after BMT. Protein C and factor VII were within the normal range before BMT, decreased significantly on day 7 to 73 and 64% respectively (p < .01) and then returned to normal values. Fibrinogen increased to 7 g/l (p < .001) on day 7 but then returned to normal levels. Fibronectin was abnormally high (p < .001) before BMT and decreased thereafter, while vWF increased (p < 0.001) for three consecutive weeks. t-PA was low (p < 0.001) before conditioning but increased thereafter. These results demonstrate the presence of endothelial lesions before BMT and acute hepatic and endothelial lesions after conditioning. Although VOD was never observed in our patients, this complication could well arise from preexisting vascular lesions due to previous chemotherapy and/or from acute hepatocytic injury, which could also be of endothelial origin, after conditioning.
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PMID:Changes in protein C, factor VII and endothelial markers after autologous bone marrow transplantation: possible implications in the pathogenesis of veno-occlusive disease. 833 49

Venous occlusion was used in 8 patients with liver cirrhosis and in 10 normals to investigate the pathomechanism of long-term elevation of plasma von Willebrand factor antigen (vWFAg) in liver cirrhosis. The following parameters were determined at baseline, and immediately, 60 min and 24 h after 10 min venous occlusion: vWFAg, ristocetin cofactor (RiCoF), in vitro platelet retention (Adeplat T), and tissue-type plasminogen activator (t-PA). Every baseline value in the liver cirrhosis group was significantly higher than in the controls. In both groups the 10-min values were significantly higher than their corresponding baseline results. Hence, comparing the two groups, in liver cirrhosis a significantly higher release of vWFAg and t-PA could be observed. These findings suggest on the one hand that the increased release contributes substantially to the sustained elevation of plasma vWF level in liver cirrhosis. On the other hand, the results indicate that not only the vascular surface of the diseased liver but most probably the total endothelium plays an important role in this phenomenon.
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PMID:Endothelium releases more von Willebrand factor and tissue-type plasminogen activator upon venous occlusion in patients with liver cirrhosis than in normals. 847 9

The aim of the present study was to test if long-term mortality could be predicted by endothelial derived haemostatic variables in a population with high morbidity due to thromboembolic disease. Plasma samples were drawn from 212 out-patients treated with oral anticoagulants, at the beginning of the study, and analyzed for mass concentration of tissue plasminogen activator (tPA) and its inhibitor (PAI-1), and von Willebrand factor. In the course of 3.8-year follow-up 45 patients died, including 38 vascular deaths. We found that all-cause mortality was significantly associated with increased levels of vWF and tPA. For vascular mortality there was a significant association with all three haemostatic variables (tPA, PAI-1, vWF). For vWF there was a 3-fold increase in total and vascular mortality in the highest quartile compared to the lowest quartile. There were 27 vascular deaths in the group of patients with a tPA-value above the median compared to 11 in those with a tPA below the median. In multivariate Cox regression analysis (including: age, sex, smoking habits, body mass index, diabetes mellitus, hypertension, tPA, PAI-1, and vWF), vWF and smoking were independently significantly associated with all-cause mortality, and tPA and age with vascular mortality. Endothelial derived haemostatic variables are predictors of total and vascular mortality in patients treated with oral anticoagulants.
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PMID:Endothelial haemostatic factors may be associated with mortality in patients on long-term anticoagulant treatment. 858 93

We studied the influence of age on mortality and severity of clotting abnormalities in 79 children (median age: 3.1 years) with meningococcal sepsis. Parameters of coagulation and fibrinolysis and plasma levels of cytokines were prospectively measured on admission. The mortality rate was 27%. The age of survivors was significantly different from that of non-survivors (p = 0.013). With the exception of FVII, vWF and t-PA, parameters of coagulation and fibrinolysis, as well as plasma cytokine levels were related to outcome. Patients were divided in two groups: younger and older than median age. The mortality in children < or = 3.1 years was 40% versus 13% in children > 3.1 years (p = 0.006). In contrast to cytokine levels, which were not different between the two age groups, fibrinogen, prothrombin, factors V, VII, VIII, vWF, protein C, antithrombin, FDP, and the ratio PA1-1/t-PA were related to age, indicating a more severe coagulopathy in children < or = 3.1 years despite a similar degree of inflammatory response. A relative deficiency of coagulation factors due to an immature state of the clotting system, as well as an inadequate fibrinolytic response, both related to age may have caused this more severe coagulative response in younger children, and may have contributed to the higher mortality rate.
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PMID:Age-related differences in outcome and severity of DIC in children with septic shock and purpura. 897 13


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