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

Despite the alluring pharmacological properties of prostacyclin and its stable analogue (iloprost), these substances are little used in plastic surgery. A case is presented in which iloprost resulted in persistent patency of the vessels supplying a free flap. A patient who had had failure of a free flap because of thrombosis distal to the arterial anastomosis had a second free flap. Thrombus formed distal to the arterial anastomosis of the second flap and recurred when the anastomosis was redone. The flap was perfused with urokinase and then iloprost. After this, iloprost was given intravenously peroperatively and for 12 hours postoperatively. Postoperatively, the patient also received aspirin, ticlopidine and heparin. The flap survived without any late complications. A literature review offers confirmation of the advantages of using iloprost if microvascular anastomoses thrombose and during the reperfusion of flaps after prolonged ischaemia.
 ...
PMID:Iloprost and salvage of a free flap. 903 19

Thrombus age as a determinant of lysis efficacy has rarely been investigated. We developed an in vitro model to study the lysis of collagen induced platelet-fibrin-thrombi of different ages. Histologically, the thrombi were similar to those found in coronary vessels of patients deceased from acute myocardial infarction or unstable angina. After 10 (TA10), 30(TA30) und 60 (TA60) min of thrombus aging thrombolysis over 30 min with urokinase alone or in combination with prostaglandin E1 was started. The efficacy of lysis with urokinase alone decreased with increasing thrombus age. After 30 min of lysis with urokinase alone weight of TA10-thrombi was reduced by 16.4 +/- 1.2 mg, of TA30-thrombi by 11.5 +/- 0.9 mg (p < 0.001 vs TA10-thrombi) and of TA60-thrombi by 7.8 +/- 1.1 mg (p < 0.001 vs TA30, p < 0.0001 vs TA10-thrombi). The addition of prostaglandin Ei augmented lysis of TA10-thrombi, after 30 min of lysis thrombus weight was reduced by 17.3 +/- 1.2 mg (p < 0.01 vs urokinase alone). Lysis of 30 and 60 min old thrombi was nearly unaffected. Thus, thrombus age is a strong predictor of lysis efficacy of in vitro collagen induced platelet-fibrin-thrombi.
 ...
PMID:[Thrombus age as a determinant of lysis efficacy of in vitro produced platelet-fibrin thrombi]. 899 9

The evolution and progression of thrombus and dissection after percutaneous transluminal coronary angioplasty (PTCA) are unknown. As part of the protocol of the Thrombolysis and Angioplasty in Unstable Angina (TAUSA) trial, 1 and 15 minutes post-PTCA angiograms were routinely performed and evaluated by the core laboratory for the presence of thrombus and either minor or major dissection. Thrombus was present at 1 minute in 4.4% of culprit lesions. This increased to 16% at 15 minutes (p < 0.005) and was equally seen in patients receiving both urokinase and placebo. Any dissection was noted in 25.2% at 1 minute versus 30.5% at 15 minutes (p < 0.08), and this trend was mainly related to an increase in major dissection with urokinase at 15 minutes versus 1 minute (10.1% vs 5.9%, respectively, p = 0.10). The in-hospital clinical outcome of patients with lesions that did or did not have thrombus or major dissection at 1 and 15 minutes was retrospectively assessed in the placebo group. The presence of either thrombus or major dissection at 1 minute was associated with a subsequent incidence of acute closure of 14% and an incidence of emergency bypass surgery of 11% (p < 0.01 compared with no thrombus or major dissection at 1 minute). The absence of thrombus and major dissection at 15 minutes (n = 173) was associated with no subsequent acute closure or emergency bypass surgery, (p < 0.05 for acute closure vs thrombus or major dissection at 15 minutes). Thrombus evolves progressively over 15 minutes after PTCA in unstable angina, whereas dissection is usually present immediately after PTCA. The absence of thrombus and major dissection at 15 minutes is associated with very low-acute in-hospital complications. Delayed angiograms following standard balloon angioplasty for unstable angina may be predictive of low complications and our study suggests a possible role for their use.
 ...
PMID:Angiographic evolution of intracoronary thrombus and dissection following percutaneous transluminal coronary angioplasty (the Thrombolysis and Angioplasty in Unstable Angina [TAUSA] trial). 906 8

Successful treatment was achieved for a patient with superior mesenteric artery thromboembolism concomitant with bilateral renal artery thromboembolism. Thrombi of the three vessels were lysed simultaneously with a three-catheter technique using short-term, high-dose urokinase followed by overnight infusion with low-dose urokinase.
 ...
PMID:Simultaneous thrombolysis of superior mesenteric artery and bilateral renal artery thromboembolisms with three transfemoral catheters. 927 55

Thrombus is a frequent cause of shunt malfunction both of the proximal end following intraventricular hemorrhage and of the distal catheter of a vascular shunt. Continued blockages may result in numerous shunt revisions until the blood has been cleared. We have treated 3 children with shunt malfunctions secondary to thrombus with urokinase, a thrombolytic agent. Two children had intraventricular hemorrhage following a shunt revision and were treated with intrashunt urokinase, and 1 with occlusion of an atrial catheter was treated with both intrashunt and systemic urokinase. All were symptomatic at the time of treatment (headaches, vomiting, full fontanel, somnolence) and all had ventriculomegaly demonstrated on computed tomography. Various dosage regimens were used with total intrashunt doses of 20,000, 50,000, and 70,000 IU. All improved clinically, computed tomography scans demonstrated improvement, and all were discharged from the hospital. There were no complications of the urokinase administration. The 2 children with proximal occlusion have not required further shunt revisions at 12 and 27 months following treatment. The infant with atrial end occlusion subsequently underwent two proximal revisions with eventual removal of the atrial catheter because of infection. We conclude the intrashunt urokinase can be of value in the treatment of shunts by blood and blood products.
 ...
PMID:Urokinase in the treatment of shunt malfunctions caused by thrombus. 934 52

Thrombus formation is a common cause of hemodialysis catheter malfunction. When thrombus or fibrin sheath restrict the flow of blood through one or both lumens, the catheter may need to be replaced. A less invasive, potentially lower cost option may be the instillation of low dose urokinase to degrade fibrin and restore catheter function. This study examines the efficacy of urokinase in improving blood flow and maintaining catheter patency. In a one-year period, urokinase was utilized in 25 dual lumen hemodialysis catheters (20 temporary, five permanent) in 22 patients. Blood flow and arterial and venous pressures were monitored before and after instillation. Urokinase administration successfully restored function in 20 catheters (80%). Paired t-tests demonstrated a significant improvement in blood flow and arterial pressure (p < 0.01) following urokinase. Catheter patency was extended for a mean of 18.0 days (range 0-90 days). The cost effectiveness of urokinase was evaluated in terms of direct costs, such as the cost of urokinase or materials to replace catheters, and indirect costs such as nursing and physician time and delays in dialysis scheduling. The results of this study suggest that judicious use of urokinase is a cost-effective, non-invasive method of restoring blood flow and extending patency in hemodialysis catheters.
 ...
PMID:Urokinase efficacy in the restoration of hemodialysis catheter function. 980 29

The necessity of maintaining a strict schedule of dialysis treatments in patients with chronic renal failure dictates that occluded access catheters be restored to full function in a timely and cost-effective manner. The records of 22 consecutive patients receiving outpatient treatment for occluded hemodialysis catheters at Osteopathic Medical Center of Texas were reviewed by the authors. Each patient had 100,000 units of urokinase in 50 ml normal saline instilled over 30 minutes through the occluded catheter. In most instances the dose was divided to allow 35 ml to the proximal port and 15 ml to the distal port. The maximum sustained blood flow rate on dialysis was recorded for each patient. The mean maximum sustained blood flow rate improved from 150 ml/min +/- 79 ml to 261 ml/min +/- 62 ml. Following infusion, improvement was obtained in 19 of 22 patients, with 14 catheters delivering blood flow greater than 250 ml/min. The total cost per treatment was $316. No adverse events were experienced. Thrombotic occlusion of extended use hemodialysis catheters can be rapidly and safely relieved in a cost-effective manner with little delay in scheduled dialysis treatments.
 ...
PMID:Short-term continuous infusion thrombolytic therapy for occluded central nervous venous dialysis catheters. 1016 60

Thrombotic occlusion is frequently a complication of central venous catheters (CVCs). The original designers and producers of CVCs recommended heparin flush regimens to prevent thrombosis and maintain patency. This has become standard practice although no studies have demonstrated a relationship between heparin flushing and reduction of catheter thrombosis. Many consider the routine use of heparin flushing innocuous. However, serious complications including drug interactions and heparin induced thrombocytopenia and thrombosis syndrome (HITS) have been reported in association with heparin flushing. Numerous studies comparing heparin to saline flushing in peripheral devices suggest equal rates of thrombotic occlusions. The purpose of this study was to examine the incidence of thrombotic occlusions in CVCs using heparin compared to saline flushing. The study involved 78 cancer patients undergoing apheresis collection for peripheral blood stem cells; 29 received saline flushes and 49 received heparin (100 U/ml of saline) flushes. Study endpoints included slow apheresis flow rate (< 50 ml/min), urokinase use for thrombolysis, and radiographic evidence of catheter thrombosis. No significant differences were found for any endpoint between the two groups. These findings suggest saline may be as effective as heparin for maintaining patency of CVCs.
 ...
PMID:Normal saline versus heparin flush for maintaining central venous catheter patency during apheresis collection of peripheral blood stem cells (PBSC). 1017 83

The role of fibrinolytic system components in thrombus formation and removal in vivo was investigated in groups of six mice deficient in urokinase-type plasminogen activator (u-PA), tissue-type plasminogen activator (t-PA), or plasminogen activator inhibitor-1 (PAI-1) (u-PA-/-, t-PA-/- or PAI-1-/-, respectively) or of their wild type controls (u-PA+/+, t-PA+/+ or PAI-1+/+). Thrombus was induced in the murine carotid artery by endothelial injury using the photochemical reaction between rose bengal and green light (540 nm). Blood flow was continuously monitored for 90 min on day 0 and for 20 min on days 1, 2 and 3. The times to occlusion after the initiation of endothelial injury in u-PA+/+, t-PA+/+ or PAI-1+/+ mice were 9.4+/-1.3, 9.8+/-1.1 or 9.7+/-1.6 min, respectively. u-PA-/- and t-PA-/- mice were indistinguishable from controls, whereas that of PAI-1-/- mice were significantly prolonged (1 8.4+/-3.7 min). Occlusion persisted for the initial 90 min observation period in 10 of 18 wild type mice and was followed by cyclic reflow and reocclusion in the remaining 8 mice. At day 1, persistent occlusion was observed in 1 wild type mouse, 8 mice had cyclic reflow and reocclusion and 9 mice had persistent reflow. At day 2, all injured arteries had persistent reflow. Persistent occlusion for 90 min on day 0 was observed in 3 u-PA-/-, in all t-PA-/- mice at day 1 and in 2 of the t-PA-/-mice at day 2 (p <0.01 versus wild type mice). Persistent patency was observed in all PAI-1-/- mice at day 1 and in 5 of the 6 u-PA-/- mice at day 2 (both p <0.05 versus wild type mice). In conclusion, t-PA increases the rate of clot lysis after endothelial injury, PAI-1 reduces the time to occlusion and delays clot lysis, whereas u-PA has little effect on thrombus formation and spontaneous lysis.
 ...
PMID:Differential role of components of the fibrinolytic system in the formation and removal of thrombus induced by endothelial injury. 1023 47

Thrombus formation at the site of atherosclerotic lesions, especially on a ruptured plaque, plays a central role in the "atherothrombosis" hypothesis. An activation of the hemostasis and a disturbed fibrinolysis are known. These alterations are especially marked in patients with acute coronary syndromes. In stable coronary artery disease, fibrinogen is elevated. Furthermore, minor alterations of the contact phase factor VII and consecutively of the thrombin system are detectable depending on the study population. Thrombin generation and activation become marked in patients with unstable angina pectoris or acute myocardial infarction. Possible reasons for this activation are an activation of the contact phase factor XII system and the release of tissue factor both from the ruptured plaque and from stimulated monocytes. The fibrinolytic system is markedly altered already in patients with stable coronary heart disease. Increased levels of tissue-type plasminogen activator and of urokinase-type plasminogen activator/receptor are measurable in atheromas. Tissue-type plasminogen activator mass concentration is systemically elevated already at early stages of atherosclerosis. Especially in patients with increased risk for acute coronary syndromes, the plasminogen activator inhibitor activity is significantly increased. Furthermore, a hypercoagulative state with increased d-dimer levels and plasmin-antiplasmin complexes can be measured. The alterations of hemostasis and especially of fibrinolysis are detectable for prolonged time period and persist much longer than the clinical symptoms of the patients. The increased plasminogen activator inhibitor activity is associated with the metabolic syndrome and constitutes an (in part genetically determined) disturbance in patients with stable or unstable coronary heart disease. However, the large intra- und interobserver as well as diurnal variability of this marker limits its use as a routine measure for risk stratification in patients. Alterations of the hemostasis and disturbances of fibrinolysis are detectable during the chronic as well as the acute phase of atherosclerosis. These changes are best documented for coronary heart disease, whereas less data are available for other manifestations of atherosclerosis. The use of newly developed molecular markers for single reaction steps of pathways instead of global functional tests and of new molecular biological methods did considerably improve the detailed knowledge on the pathomechanisms of the development of atherosclerosis, making the development of targeted therapies, e.g., against receptors possible. Future studies will investigate the quantitative impact of the various activated pathways (cause or reaction) and the effects of interventions on these pathomechanisms in patients with acute coronary syndromes. Studies will have to focus especially on the meaning of polymorphisms, early changes in the development of atherosclerosis and interactions with inflammatory processes.
 ...
PMID:[Blood coagulation and fibrinolysis in arteriosclerosis]. 1041 53


<< Previous 1 2 3 4 5 6 Next >>