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)

We examined the localization of transforming growth factor (TGF)-beta in first-trimester and term human decidua and chorionic villi and explored the role of this factor on the proliferation and differentiation of cultured trophoblast cells. Two antibodies, 1D11.16.8, a mouse monoclonal neutralizing antibody capable of recognizing both TGF-beta 1 and TGF-beta 2 and CL-B1/29, a rabbit polyclonal antibody capable of recognizing TGF-beta 2, were used to immunolocalize TGF-beta in fixed, paraffin-embedded, or fixed, frozen sections of placenta and decidua, providing similar results. Intense labeling was observed in the extracellular matrix (ECM) of the first-trimester decidua and cytoplasm of term decidual cells. Syncytiotrophoblast cell cytoplasm as well as the ECM in the core of the chorionic villi of both first-trimester and term placentas exhibited a moderate degree of labeling. Strong cytoplasmic labeling was observed in the cytotrophoblastic shell of the term placenta. To examine the role of TGF-beta on trophoblast proliferation and differentiation, early passage cultures of first-trimester and primary cultures of term trophoblast cells were established and characterized on the basis of numerous immunocytochemical and functional markers. These cells expressed cytokeratin, placental alkaline phosphatase, urokinase-type plasminogen activator, and pregnancy-specific beta glycoprotein, but not factor VIII or 63D3; they also produced hCG and collagenase type IV. Exposure of first-trimester trophoblast cultures to TGF-beta 1 significantly inhibited proliferation in a dose-dependent manner. An antiproliferative effect was also noted in the presence of TGF-beta 2. These effects were abrogated in the presence of the neutralizing anti-TGF-beta antibody (1D11.16.8) in a concentration-dependent manner. In a 3-day culture, exogenous TGF-beta 1 stimulated formation of multinucleated cells by the first trimester as well as term trophoblast cells. Addition of neutralizing anti-TGF-beta antibody to first-trimester trophoblast cells stimulated proliferation beyond control levels in a 24-h culture and reduced formation of multinucleated cells in a 3-day culture, indicating the presence of endogenous TGF-beta activity. These results indicate that TGF-beta produced at the human fetal-maternal interface plays a major regulatory role in the proliferation and differentiation of the trophoblast.
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PMID:Localization of transforming growth factor-beta at the human fetal-maternal interface: role in trophoblast growth and differentiation. 137 70

Nine healthy volunteers and 23 patients with various types of von Willebrand disease were studied before and after DDAVP infusion. We investigated the behaviour of factor VIII/von Willebrand factor measurements, and of tissue plasminogen activator and urokinase-type plasminogen activator. In mild von Willebrand disease the increase of both plasminogen activators was similar to that seen in normal controls. A different fibrinolytic behaviour was found in the type I platelet low and in the type III von Willebrand disease patients. An impaired and absent fibrinolytic response to DDAVP was seen in the former and in the latter von Willebrand disease, respectively. A close relation between either u-PA and t-PA or von Willebrand factor was observed. The possibility of a linkage among these three proteins was discussed.
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PMID:Urokinase-type plasminogen activator release after DDAVP in von Willebrand disease: different behaviour of plasminogen activators according to the synthesis of von Willebrand factor. 152 8

Hetastarch, the currently marketed preparation of hydroxyethyl starch, affects coagulation by prolonging partial thromboplastin, prothrombin, and bleeding times; by lowering clotting proteins such as fibrinogen via hemodilution; by lowering clotting factor VIII (coagulant, von Willebrand antigen, and von Willebrand activity) to a greater degree than can be explained simply by hemodilution (i.e., presumably factor VIII affected by both hemodilutional plus additional, independent effects); and, finally, by shortening thrombin, reptilase, and urokinase-activated clot lysis times. Pentastarch, a new analog of hetastarch, was found to exert lesser effects on blood coagulation, despite its greater hemodiluting properties. When compared with hetastarch, pentastarch had little effect on factor VIII (except that due to hemodilution), shortened thrombin times to a significantly lesser degree, exerted no effect on the urokinase-activated clot lysis time, and did not prolong the bleeding time. Even when plasma hydroxyethyl starch levels were similar, pentastarch seemed to alter the results of coagulation assays to lesser degree than did hetastarch, which suggests the possibility of greater safety. Therefore, pentastarch may be a desirable drug, not only for leukapheresis, but also for plasma volume expansion in trauma and surgical patients who often have additional hemostatic abnormalities that place them at increased risk of hemorrhage.
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PMID:Pentastarch may cause fewer effects on coagulation than hetastarch. 245 88

Although conventional biotechnology used for the synthesis of antibiotics, vitamins, amino acids, nucleotides, enzyme inhibitors and immunomodulating compounds has still a major impact in the production of pharmaceutical compounds, the importance of the new biotechnology is increasing. Whereas in conventional biotechnology naturally occurring strains are screened for production of pharmacologically active compounds, in new biotechnology known organisms are programmed by genetic engineering to produce a distinct protein or glycoprotein of human origin for substitution therapy. Such complex compounds from new biotechnology can be divided into products which might replace compounds which are already on the market by safer recombinant products such as human insulin, human growth hormone, urokinase, factor VIII and products which are new on the market such as interferons, lymphokines, tissue plasminogen activator, oligonucleotide probes, monoclonal antibodies and subunit vaccines. However, only a few of these recombinant products have reached the market such as human insulin, interferon alpha, interferon beta, human growth hormone and recombivax HB. In most cases, depending on the difficulties in demonstrating clinical efficacy, the investigated drugs have reached the marketing phase much faster than conventional chemical drugs. Return on investment of biotechnical produced pharmaceutics mainly depends on the issues of whether the product has to compete with chemically synthesized drugs, whether it is totally new but competes with other bioproducts, whether it is exceptional but the proof of clinical efficacy is difficult, or whether it is totally new and clinical studies are promising.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Biobusiness in the pharmaceutical industry. 343 5

The fibrinolytic system comprises a proenzyme, plasminogen, which can be converted to the active enzyme, plasmin, which degrades fibrin. Plasminogen activation is mediated by plasminogen activators, which are classified as either tissue-type plasminogen activators (t-PA) or urokinase-type plasminogen activators (u-PA). Inhibition of the fibrinolytic system may occur at the level of the activators or at the level of generated plasmin. Plasmin has a low substrate specificity, and when circulating freely in the blood it degrades several proteins including fibrinogen, factor V, and factor VIII. Plasma does, however, contain a fast-acting plasmin inhibitor, alpha 2-antiplasmin, which inhibits free plasmin extremely rapidly but which reacts much slower with plasmin bound to fibrin. A "systemic fibrinolytic state" may, however, occur by extensive activation of plasminogen and depletion of alpha 2-antiplasmin. Clot-specific thrombolysis therefore requires plasminogen activation restricted to the vicinity of the fibrin. Two physiological plasminogen activators, t-PA and single-chain u-PA (scu-PA) induce clot-specific thrombolysis, via entirely different mechanisms, however. t-PA is relatively inactive in the absence of fibrin, but fibrin strikingly enhances the activation rate of plasminogen by t-PA. This is explained by an increased affinity of fibrin-bound t-PA for plasminogen and not by alteration of the catalytic rate constant of the enzyme. The high affinity of t-PA for plasminogen in the presence of fibrin thus allows efficient activation on the fibrin clot, while no significant plasminogen activation by t-PA occurs in plasma. scu-PA has a high affinity for plasminogen (Km = 0.3 microM) but a low catalytic rate constant (kcat = 0.02 sec-1). However, scu-PA does not activate plasminogen in plasma in the absence of a fibrin clot, owing to the presence of (a) competitive inhibitor(s). Fibrin-specific thrombolysis appears to be due to the fact that fibrin reverses the competitive inhibition. The thrombolytic efficacy and fibrin specificity of natural and recombinant t-PA has been demonstrated in animal models of pulmonary embolism, venous thrombosis, and coronary artery thrombosis. In all these studies intravenous infusion of t-PA at sufficiently high rates caused efficient thrombolysis in the absence of systemic fibrinolytic activation. The efficacy and relative fibrinogen-sparing effect of t-PA was recently confirmed in three multicenter clinical trials in patients with acute myocardial infarction.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Molecular mechanisms of fibrinolysis and their application to fibrin-specific thrombolytic therapy. 355 13

The treatment of prostatic cancer with oestrogen has been reported to be associated with cardiovascular side effects. Twenty patients with recently diagnosed prostatic cancer were randomly allocated to oestrogen therapy or orchidectomy. As compared to healthy age matched controls the patients with prostatic cancer had increased base-line levels of fibrinogen (5.2 +/- 1.9 g/l versus 3.7 +/- 1.0 g/l; p less than 0.002) and factor VIII:C (166 +/- 62% versus 110 +/- 29%; p less than 0.001). During oestrogen therapy factor VII increased from 99 +/- 22% to 150 +/- 47% (p less than 0.001), while the antithrombin III level fell from 93 +/- 10% to 81 +/- 13% (p less than 0.001). Both these changes are in the direction of a hypercoaguable state. Concomitantly plasminogen increased from 113 +/- 14% to 142 +/- 18% (p less than 0.001), urokinase inhibiting activity fell from 105 +/- 10% to 90 +/- 9% (p less than 0.001) and C1-esterase inhibitor fell from 110 +/- 17% to 86 +/- 22% (p less than 0.05) in the oestrogen therapy group. After orchidectomy there were no changes in the activators and inhibitors of coagulation and fibrinolysis studied as compared to base-line values. Furthermore the D dimer, a specific degradation product of crosslinked fibrin increased from a normal to a pathological value in 4 out of 8 tested patients after 6 weeks of oestrogen therapy, but in none out of 9 tested patients in the orchidectomy group. Briefly stated, patients with prostatic cancer treated with oestrogen have increased levels of factor VII, factor VIII:C and fibrinogen and a decreased level of antithrombin III.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Activators and inhibitors of coagulation and fibrinolysis in patients with prostatic cancer treated with oestrogen or orchidectomy. 379 20

Confluent cultures of endothelial cells from human umbilical cord were used to study the effect of activated human protein C (APC) on the production of plasminogen activators, plasminogen activator-inhibitor, and factor VIII-related antigen. Addition of APC to the cells in a serum-free medium did not affect the production of tissue-type plasminogen activator (t-PA) or factor VIII-related antigen; under all measured conditions, no urokinase activity was found. However, less plasminogen activator-inhibitor activity accumulated in the conditioned medium in the presence of APC. This decrease was dose dependent and could be prevented by specific anti-protein C antibodies. No decrease was observed with the zymogen protein C or with diisopropylfluorophosphate-inactivated APC. APC also decreased the t-PA inhibitor activity in endothelial cell-conditioned medium in the absence of cells, which suggests that the effect of APC is at least partly due to a direct effect of APC on the plasminogen activator-inhibitor. High concentrations of thrombin-but not of factor Xa or IXa--had a similar effect on the t-PA inhibitor activity. The effect of APC on the plasminogen activator-inhibitor provides a new mechanism by which APC may enhance fibrinolysis. The data suggest that activation of the coagulation system may lead to a secondary increase of the fibrinolytic activity by changing the balance between plasminogen activator(s) and its (their) fast-acting inhibitor.
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PMID:Activated protein C decreases plasminogen activator-inhibitor activity in endothelial cell-conditioned medium. 391 96

The efficacy and the safety of a new urokinase dosage regimen (loading dose 250,000 IU, initial maintenance dosage 2,000 IU/kg/h in combination with heparin) was studied in ten cases of deep vein thrombosis with regard to the changes of the blood coagulation and fibrinolytic enzyme system. The coagulation analyses demonstrated a pronounced activation of the fibrinolytic system with a statistically significant (p less than 0.05) shortening of the euglobulin clot lysis time and increase of the FDP. The fibrinogen concentration ranged from 50-100 mg/dl already after 12-36 hours. Plasminogen was reduced by 63%, alpha 2-macroglobulin by 32% and factor VIII:C by 42% (p less than 0.05 each). The decrease of fibrinogen (Clauss method) related well to the method of Ratnoff and Menzie, the reduction of plasminogen and the shortening of the euglobulin clot lysis time. According to our data, a sufficient plasma fibrinogenolytic activity may permit on its own an assessment of an adequate therapy with urokinase and the requirements of dose adjustment. The dosage regimen applied here proved effective and readily controllable. Relevant side reactions were not observed.
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PMID:Blood coagulation changes during effective thrombolysis using urokinase and heparin. 617 40

The effects of various concentrations of plasmin and activated protein C on the factor VIII procoagulant activity (VIII:C) and coagulant antigen (VIII:CAg) were studied in factor VIII concentrates and normal plasma. Small amounts (0.1 CTA U/ml) of plasmin rapidly destroyed VIII:C, and affected, but did not destroy VIII:CAg, in factor VIII concentrates. In normal plasma larger amounts of plasmin (1.8 CTA U/ml) was required to inactivate VIII:C in order to exceed the neutralizing capacity of alpha 2-antiplasmin. VIII:CAg was unchanged indicating a limited proteolysis. The difference between VIII:C and VIII:CAg was found also in urokinase-activated plasma. Activated protein C (5 micrograms/ml), in the presence of Ca2+ and phospholipids, inactivated VIII:C without affecting VIII:CAg in a high purity factor VIII concentrate. Higher concentrations of activated protein C (25 micrograms/ml) caused a slight decrease of VIII:CAg, even in the absence of Ca2+ and phospholipids, but did not change VIII:CAg in normal plasma or serum.
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PMID:The effects of plasmin and protein Ca on factor VIII:C and VIII:CAg. 622 18

A comprehensive study of haemostasis has been performed in a homogeneous group of 25 adult patients with conservatively treated chronic uraemia. We have found prolonged bleeding time, impaired platelet adhesiveness and aggregation, and decreased platelet factor 3 activity, increased values of fibrinogen, of factor VIII activity and related antigen, and of combined levels of factors II, VII and X. Non-significantly abnormal concentrations of factor XIII and of plasminogen and significantly lower values of plasminogen activators and higher values of urokinase inhibitors and anti-plasmin have also been found. Fibrinogen degradation products were detected in the urine of some patients.
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PMID:Comprehensive study of haemostasis in chronic uraemia. 640 79


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