Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.4.21.73 (urokinase-type plasminogen activator)
 10,685 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Thrombolytic treatment of deep vein thrombosis remains controversial. It has never been demonstrated that the late postthrombotic syndrome may be diminished by the faster dissolution of the clots induced by streptokinase or urokinase. On the other hand are the hemorrhagic side effects associated with thrombolysis well described (lethality of 0.6%). Thrombolysis should be performed preferably under controlled conditions of a clinical study. It is indicated only in young patients with symptoms for less than 7 days of a first thrombosis. Initial results from second generation fibrinolytic substances such as rt-PA (alteplase) do not change this view drastically.
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PMID:[Thrombolysis in deep venous thrombosis: critical review]. 178 Jul 95

6 patients with deep vein thrombosis triggered by drug therapy, that is oral contraceptives in 5 and the anticonvulsant tranexamic acid in 1, are described. These cases were among 40 symptomatic patients out of a total group of 81 with congenital coagulation inhibitor defects studied over 10 years at the Institute of Medical Semiotics, Padua, Italy. The 5 women with deep vein thrombosis ranged in age from 20-34, and had typically taken oral contraceptives containing 35 mcg ethinyl estradiol in combined or phasic preparations, for 1 to 8 cycles. One women, however, had been prescribed sequential pills containing 50 mcg mestranol. Another had taken oral contraceptives with impunity for 3 years, but developed deep vein thrombosis after taking tranexamic acid for 10 days. All recovered after heparin or oral anticoagulant therapy, except a 21 year old whose condition evolved into complete ileo-caval obstruction up to the renal veins, and was treated with urokinase. the congenital defects involved were 3 probable heterozygous true deficiencies of antithrombin III (low ATIII antigen and activity); a decreased protein C antigen to factor X antigen ratio; a heparin cofactor II deficiency; and a type I protein S deficiency (low free protein S, with normal total protein S and normal levels of C4B-bp.) While 5 of these 6 women had family histories of thromboembolic disease, the drug was prescribed without knowing that they were heterozygous for a coagulation inhibitor deficiency. The incidence of drug-induced thromboembolism was low in this series overall, where most of the events were triggered by surgery or trauma.
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PMID:The role of drugs, particularly oral contraceptives, in triggering thrombosis in congenital defects of coagulation inhibitors: a study of six patients. 178 39

In the present study 57 consecutive patients with a first episode of venographically proven deep vein thrombosis were investigated to evaluate the release of tissue-type plasminogen activator (t-PA) and of urokinase-type plasminogen activator (u-PA) in response to DDAVP stimulation as well as the resting plasminogen activator inhibitor (PAI) concentration, comparing this to the results obtained in 66 similar patients with a clinical suspicion of thrombosis but with a normal venogram. All assays were performed without knowledge of the patient's status. Four patients in the deep vein thrombosis-group (7%) had an absent u-PA antigen response upon DDAVP infusion, while a normal response was observed in all control subjects. Patients and controls showed similar increases in t-PA antigen level upon DDAVP. High resting PAI antigen levels were encountered in 5 patients in the deep vein thrombosis-group (9%) and in 6 subjects in the control group (9%). The results from this controlled study indicate that a defective release of u-PA may occur in patients with deep vein thrombosis and may have pathogenetic significance. Furthermore it is concluded that elevation of PAI levels cannot be considered as a specific risk factor for venous thrombosis.
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PMID:Deep vein thrombosis and fibrinolysis. Defective urokinase type plasminogen activator release. 179 91

Recombinant human rt-PA was administered to 22 patients with deep vein thrombosis at a dosage of 30 to 120 mg/day (0.5 to 1.76 mg/kg body weight/24 hr) over 2 to 10 days. rt-PA induced phlebographically documented substantial recanalization in 18 of 21 patients. The lowest dose of 0.5 mg/kg/24 hr tested here was thrombolytically effective, whereas a dose of 0.95 mg/kg/24 hours and more led to hemorrhagic complications and premature discontinuation of therapy in four of six patients. Blood clotting analysis did not reveal any substantial decrease in fibrinogen concentrations, whereas the euglobulin clot lysis time and thromboelastography demonstrated a systemic fibrinolytic effect. Therapy with rt-PA can thus be considered as an alternative and effective method of therapy in treatment of deep vein thrombosis. The results of this study show that even a dosage of lower than 0.5 mg/kg/24 hr might prove to be effective. Further studies would be required to show whether the fibrin specificity of rt-PA leads to a superiority of this fibrinolytic substance over the conventional thrombolytic agents, streptokinase and urokinase.
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PMID:Fibrinolytic therapy of deep vein thrombosis with continuous intravenous infusion of a recombinant tissue plasminogen activator. 190 29

Experience and review of the literature suggest that when deep venous thrombosis does occur, standard anticoagulation with heparin followed by Coumadin is the mainstay of treatment for both deep venous thrombosis and pulmonary emboli. However, thrombolytic therapy with urokinase or streptokinase may benefit selected patients. Percutaneous caval interruption is the optimal technique to prevent pulmonary embolization, but should be reserved for patients who have contraindications to anticoagulation therapy or recurrent emboli despite adequate anticoagulation. Selected high risk patients may also be candidates for caval interruption.
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PMID:Venous thromboembolism: anticoagulation, lysis, or filter? 194 28

Acute and subacute deep venous thrombosis can be followed by two serious complications: pulmonary embolism feared in the early stadium and the postthrombotic syndrome (PTS) as a late complication. After a lapse of months and years there might appear a complete or incomplete recanalization, but the valves of the veins will be destroyed. Therefore it is understandable to strive first an active therapy as thrombectomy or thrombolysis to remove thrombosis. There will be released a physiological tissue plasminogen activator from the endothelium of the vein increasing a local fibrinolytic activity. But it is not strong enough to reopen the occlusion within a few days. This is only possible adding exogenous activators as streptokinase, urokinase and recently rt-PA. Heparin is well known at low-dose subcutaneously for thrombosis prophylaxis. The high doses of heparin infusion intravenously with 30-40,000 units daily are used "therapeutically" inhibiting growth-promotion of the thrombus and reducing the incidence of pulmonary embolism markedly. In respect of a postthrombotic syndrome (oedema, leg ulcers) it needs the evaluation of the early and follow up late results and the analysis of efficiency and risk of the two models of treatment. It was necessary comparing the success rate of reopening of the occluded veins after some days and follow up 5 or 6 years in clinical studies. The reopening rate in thrombolysis was about 3 times higher than in heparin therapy. But in contrast bleeding was 3 times lower in heparin therapy. For the long term follow up, physical examination, doppler-sonography phlebodynamometry and vein occlusion plethysmography were assessed. The acute intervention, regarding treatment, turned out to be the crucial prognostic parameter. Syndromes and clinical findings did indeed correlate quite well with the outcome of fibrinolytic treatment. Postthrombotic syndrome was rare in cases with complete patency. In cases where patency was only partially or not at all achieved, postthrombotic syndrome was present to a higher degree the more central and the more extensive the remaining thrombus was. In deep venous thrombosis of the lower extremity thrombolytic therapy is recommended mostly to younger patients with acute, the popliteal and the femoral vein including thrombosis, except of contraindications. More over in each of an individual case it has to be decided whether the aggressive or conservative therapy is to prefer.
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PMID:[The treatment of deep venous thrombosis. Thrombolysis vs heparin]. 209 22

Recombinant tissue plasminogen activator (rt-PA) is a thrombolytic agent characterized by elevated but not absolute fibrin specificity. However, its therapeutic dose is high and associated with a variable degree of systemic activation of the fibrinolytic system. Thrombolytic drugs are widely used in acute myocardial infarction and have now begun to be considered for deep vein thrombosis (DVT), pulmonary embolism (PE), and peripheral artery thrombosis (PAT) as well. Although anticoagulant therapy is effective in reducing the immediate complications of venous thromboembolism, thrombolytic therapy has various advantages over anticoagulant therapy, including lysis of thrombi with recanalization of venous circulation, reduction of venous valve damage and prevention of post-phlebitic syndrome. The different dosage regimens of rt-PA recently evaluated (0.71 to 1.76 mg/kg/24 h for 2-4 days) in DVT have caused consistent thrombolysis but also excessive bleeding. The optimal therapeutic range for rt-PA in DVT remains to be determined. Thrombolytic therapy is superior to heparin treatment only in hemodynamically compromised patients with massive PE. The minor systemic fibrinolytic effect and the faster action on thrombi of rt-PA compared with the first generation thrombolytic agents, streptokinase (SK) and urokinase (UK), are very interesting and explain the positive results recently obtained in PE with this drug (50 mg over 2 h, followed, if necessary, by 40-50 mg over 4-5 h) by Goldhaber and Verstraete.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:[rt-PA in extracardiac thromboembolic vascular occlusions]. 211 73

In this review, an attempt has been made to present new data on the mechanisms that can be involved in DVT and to emphasize the role of the cell in these processes. It has been demonstrated that cells can mediate the relevant expression of tissue factor without cell disruption and that the fibrinolytic responses can also be modulated by the cells. It has also been demonstrated that the fibrinolytic system seems to be designed to work on the cell surface based upon (1) the existence of specific receptors, (2) the modulation of the expression of these receptors and (3) the comprehensive increase in plasmin generation by up-regulating, for example, the plasminogen receptors. It could also be worthwhile to attempt to explain some beneficial effects of drugs such as heparins by studying their action on these compartments. It is important to note that recently Rosenfeld et al. have described an increase in t-PA and u-PA binding to endothelium by pre-incubation of endothelial cells with unfractionated heparin. This work would be a first step in a very exciting and interesting new era in the prevention of venous thromboembolism.
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PMID:Biochemical aspects of the pathogenesis of venous thrombosis. 228 80

A case of pulmonary embolism associated with diabetes insipidus is reported in an 18-year-old male. The patient, who had been treated with DDAVP for diabetes insipidus and hydrocortisone for hypocorticism for two years after first operation for the removal of craniopharyngioma, was admitted with recurrence of that tumor. Diabetes insipidus immediately after second operation was controlled with intermittent drip infusion of a small amount of aqueous pitressin under monitorings of body weight hourly using a patient weighing system to keep the weight changes within +/- one kilogram. Serum and urine electrolytes levels, osmolarity, and free water clearance were also monitored every three hours to maintain water-electrolytes balances appropriately. Postoperative course had been uneventful except that CSF rhinorrhea occurred 7 days after operation. The patient was, then, kept in bed with horizontal plane to avoid further leakage of CSF. Two days later, he developed chest pain suddenly with tachypnea, tachycardia, and general cyanosis. The arterial-BGA showed PaO2 of 53.5mmHg and PaCO2 of 35.3mmHg in room air. The definite diagnosis of pulmonary embolism was made by technetium microaggregate lung perfusion scans and by pulmonary angiograms. The patient was treated with heparin, 15000IU/day, and urokinase, 720000IU/day. The symptoms due to pulmonary embolism had improved gradually within a couple of weeks. Recent articles have shown an unexpected high incidence of deep vein thrombosis and pulmonary embolism in neurosurgical patients associated with the elevation of blood coagulability. Brain tumors, especially suprasellar mass with hypothalamic dysfunction have been suggested to cause thromboembolic disorders frequently. The clinical course was described and factors causing pulmonary embolism on this patient was discussed.
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PMID:[A case of pulmonary embolism with diabetes insipidus developed after removal of craniopharyngioma]. 233 47

Many investigators have reported about beneficial results with thrombolytic therapy in patients with acute pulmonary embolism. Streptokinase and urokinase have been used for more than 15 years, but the conditions of use of these agents still remain controversial. Optimal dosage and treatment schedule are still evolving. For streptokinase most investigators adopt a fixed dosage schedule: a loading dose of 250,000 units followed by a maintenance infusion of 100,000 units per hour for 24 to 72 hours. For urokinase numerous dosage regimens have been used such as: high dosage schedule 4,400 units per kilogram per hour for twelve to 24 hours with or without loading dose; moderate dosage 1,600 to 2,000 units per kilogram per hour for 24 hours and low dosage in bolus. With these treatments there is a trend to reduced in-hospital-mortality in massive pulmonary embolism; the early pulmonary revascularization and the hemodynamic improvement are higher than those noticed with heparin. These results are obtained with a minimum of complication essentially bleeding in 10 or 15%; most bleeding being located at puncture site. More recently, new thrombolytic agents have been used in acute pulmonary embolism. Only four studies have tested rt-PA which is effective and relatively safe, but the optimal dose regimens remain to be determined. Less information is available concerning Anisoylated Plasminogen Streptokinase Activator Complex (APSAC), the angiographic improvement seems to be rapid and important (50% on average) but the decrease of fibrinogen is important too and comparable with streptokinase. Considering the good results of thrombolytic treatment of acute submassive and massive pulmonary embolism, there is a doubt as to whether the pulmonary embolectomy has any place in the pulmonary embolism patients except in those with cardiac arrest. In the near future new thrombolytic drugs could be more efficient on pulmonary embolism and deep venous thrombosis, and thus the bleeding risk might be decreased.
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PMID:Thrombolytic treatment of acute pulmonary embolism. 250 Mar 88


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