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

Clinicians followed 30 women, 18-37 years old, attending the family planning clinic of Falu Hospital in Sweden to compare the effect of a long interval of an oral contraceptive (OC) (30 mcg ethinyl estradiol + 150 mcg desogestrel) on the hemostasis system, lipid metabolism, and hormone binding proteins with that of a traditional 3-week regimen. They randomly allocated 20 women to the long-interval group (group I) and 10 to the 3-week group (group II). The long-interval consisted of 9 weeks taking the OC and 1 week not taking the OC. Between baseline and 12 months, sex hormone binding globulin (SHBG) levels increased 409% in group I (p .001) and 341% in group II (p .01). Corticosteroid binding globulin (CBG) levels increased 294% (p .001) for group I and 173% for group II. SHBG and CBG levels (markers of estrogenicity) were not significantly different between the 2 groups, however. Limited, insignificant changes took place with lipoprotein cholesterol fractions. VLDL-triglycerides and LDL-triglycerides increased significantly in group I (0.31-0.57 mmol/l) and group II (0.21-0.27 mmol/l) (p .05). Fibrinogen, factor VII, and thrombin/antithrombin III complex increased significantly in group I at 3 and 12 months. They had also increased in group II but not significantly. The coagulation inhibitors (i.e., antithrombin III, protein C, and protein S) remained virtually the same. Levels of tissue plasminogen activator antigen and tissue plasminogen activator inhibitor activity, both of the fibrinolytic system, fell (significant decrease only in group I). These findings show that the desogestrel-containing low-dose OC has limited effects on lipid metabolism, particularly the cholesterol subfractions, regardless of the regimen. It does increase minimally coagulation parameters, but the fibrinolytic system offsets this increase. In conclusion, the long-interval regimen is as safe as the 3-week regimen.
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PMID:Hemostasis profile and lipid metabolism with long-interval use of a desogestrel-containing oral contraceptive. 795 14

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

Treatment with recombinant human erythropoietin (rhEPO) for the anemia of end-stage renal disease has been associated with thrombotic complications. To detect prothrombotic changes in autologous blood donors given 500 U/kg rhEPO subcutaneously (twice weekly during a 3-week period), changes in variables of hemostasis and fibrinolysis and in blood rheology before and at the end of treatment were investigated. In 21 patients, platelet count increased from 272 +/- 55 x 10(9)/L to 313 +/- 55 x 10(9)/L (p < 0.05). Although activated partial thromboplastin time and protein C antigen decreased significantly during rhEPO treatment, these changes remained within normal ranges. No changes in the hemostatic variables prothrombin time, fibrinogen, factor V, von Willebrand factor antigen, antithrombin III activity, protein S antigen, and prothrombin fragments F 1 + 2 were found. Measurements of plasminogen activity, alpha 2-antiplasmin activity, tissue plasminogen activator, and plasminogen activator inhibitor-1, representing variables of fibrinolysis, were normal and constant during the study. In 5 patients no changes in red cell deformability and whole blood viscosity, corrected for differences in hematocrit, were observed. Plasma viscosity showed a slight but clinically not relevant increase in 4 out of 5 patients. The absence of evident (pro)thrombotc changes in this study confirms the safety of high-dose rhEPO therapy in autologous blood donors, who donate 2 units (i.e., 2 x 450 ml) of blood.
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PMID:The effect of recombinant human erythropoietin on hemostasis, fibrinolysis, and blood rheology in autologous blood donors. 803 97

In eight patients with Legg-Perthes disease, we assessed the etiologic roles of thrombophilia caused by protein C and protein S deficiency and hypofibrinolysis mediated by low levels of tissue plasminogen activator activity. We speculated that thrombosis or hypofibrinolysis were common causes of Legg-Perthes disease. Three of the eight patients had protein C deficiency; they came from kindreds with previously undiagnosed protein C deficiency. In one of these three kindreds there were six protein C-deficient family members (beyond the proband child), four of whom had thrombotic events as adults. One of the eight patients had protein S deficiency, as did his brother who had sustained mesenteric vein thrombosis at age 43. One of the eight patients who had normal proteins C, S, and antithrombin III had hypofibrinolysis, failing to elevate tissue plasminogen activator activity after 10 min of venous occlusion at 100 mm Hg. Plasminogen activator inhibitor, alpha 2-antiplasmin, and fibrinogen values were normal in all eight patients. Beyond their Legg-Perthes disease, none of the eight patients had evidence for venous thrombosis. Of the eight patients, four had thrombophilia and one had hypofibrinolysis, disorders that we believe contributed to thrombotic venous occlusion of the femur with subsequent venous hypertension and bone death that characterize Legg-Perthes disease.
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PMID:Protein C and S deficiency, thrombophilia, and hypofibrinolysis: pathophysiologic causes of Legg-Perthes disease. 804 73

Activated protein C (APC)-protein C inhibitor (PCI) complex and APC-alpha 1antitrypsin (alpha 1AT) complex levels were measured in 29 patients positive for lupus anticoagulant (LA). LA was considered positive if two of the following three criteria were fulfilled: (1) prolongation of the activated partial thromboplastin time, (2) prolongation of the kaolin clotting time (KCT) and KCT mixing test, and (3) prolongation of the dilute Russell's viper venom time (DRVVT) and DRVVT/DRVVT with high lipid concentration. Plasma thrombin-antithrombin III (AT-III) complex and plasmin-alpha 2-antiplasmin inhibitor complex levels in patients positive for LA were increased slightly, but not significantly, and FDP-D-dimer and t-PA levels were not markedly increased. Plasma PAI-1 level in the LA-positive patients was significantly increased compared with normal volunteers. AT-III activity, protein C antigen, PCI antigen, and protein S antigen levels in the LA-positive patients were virtually normal, while protein C activity was slightly, but not significantly, decreased. APC-PCI complex level was increased in all LA-positive patients, and was not detectable in patients with systemic lupus erythematosus and normal volunteers. APC-alpha 1AT complex was increased slightly, in only two LA-positive patients; it was not detectable in the other patients or in the normal volunteers. These findings suggest that patients positive for LA are in a hypercoagulable state and that protein C activity in such patients is decreased, due to the activation of this protein.
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PMID:Increased activated protein C-protein C inhibitor complex level in patients positive for lupus anticoagulant. 805 49

This review has stressed the common hereditary and acquired blood protein defects associated with thrombosis. The most common of the hereditary defects appear to be antithrombin, protein C, and protein S deficiency and the most common acquired defects are anticardiolipin antibodies and the lupus anticoagulant. Therefore these are the defects that should first be looked for in an individual with unexplained thrombosis. If these more common defects are not found, then the rarer defects, including heparin cofactor II, plasminogen or tissue plasminogen activator deficiency, dysfibrinogenemia, or elevated PAI-1 should next be sought. The importance of finding these defects has significant implications for therapy of the individual patient and for institution of family studies to identify, inform, and possibly treat others at risk. It is expected that as knowledge of hemostasis expands, more hereditary and acquired defects, such as elevated lipoprotein(a) or defects of extrinsic (tissue factor) pathway inhibitor may be associated with enhanced risks of thrombosis.
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PMID:Syndromes of hypercoagulability and thrombosis: a review. 805 29

The occurrence of thrombotic events remains an important clinical problem in Essential Thrombocythemias (ET). Thus, hemostatic, fibrinolytic and vascular status was investigated in 16 patients (5 males and 11 females) with ET. Among them five presented thromboses in their past history. Platelet hyperactivation, as evidenced by a mean three-fold increase in plasma betathromboglobulin (beta TG), was observed in 13 among 16 patients; surprisingly this activation was present even when the platelet count was normal (in two patients) or subnormal, below 600 x 10(9)/l (in 11 patients). The mean value was 104 +/- 57 IU/ml significantly different from that of normal controls (35 +/- 16.5 IU/ml) (p < 0.001). An artefactual in vitro platelet activation was ruled out by the concomitant measurement of platelet factor 4 (PF4). D-dimers fibrin degradation products (D-Di FDP) were normal in all patients. Vascular endothelial cell function parameters were not markedly modified. The mean value of plasma thrombomodulin (TM) was found slightly but not significantly increased (60.1 +/- 4.9 ng/ml versus 49.1 +/- 10.0 ng/ml in controls). The values of plasma TM correlated neither with that of the platelet count nor with that of plasma beta TG or plasma PF4. The mean values of plasma protein S, von Willebrand factor (vWF), plasminogen activator inhibitor type 1 (PAI-1), tissue plasminogen activator (tPA) were normal and were not correlated neither with that of plasma TM nor with that of plasma beta TG.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Platelet hyperactivation in patients with essential thrombocythemia is not associated with vascular endothelial cell damage as judged by the level of plasma thrombomodulin, protein S, PAI-1, t-PA and vWF. 771 May 37

The long-term effects of tamoxifen on alterations in haemostasis which could lead towards thrombosis were investigated in 149 women who were disease-free for at least 5 years following mastectomy for breast cancer. All participants were randomized to receive tamoxifen as a post-surgical adjuvant treatment (89 patients, treated group) or not (60 patients, controls) for at least 2 years. 5.62% of the cases treated with tamoxifen suffered a venous thrombosis, while no thromboembolism was reported in the control group. No significant differences were observed between groups in the global clotting times, fibrinogen, fibrinolytic factors, or in the concentration of the main natural anticoagulants, antithrombin III (AT-III), protein C(PC) and protein S (PS). However, when the treated group was sub-divided, current users (n = 18) of the drug (median treatment duration 72 months) had significantly lower AT-III (P < 0.05) and PC (P < 0.05) activities, together with higher levels of plasminogen activity (P < 0.01) and tissue plasminogen activator antigen (P < 0.01), compared with 71 ex-users (who mostly received treatment for 2 years) and controls. We conclude that long-term treatment with tamoxifen for 2 or more years tends to reduce both AT-III and PC, a situation possibly predisposing towards thrombosis. Monitoring haemostasis in tamoxifen-treated breast cancer patients is therefore advisable.
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PMID:The influence of tamoxifen in vivo on the main natural anticoagulants and fibrinolysis. 814 87

This study of 49 patients with spontaneous venous and arterial thrombosis identified 27 with hypercoagulable states: 13 had only venous thrombosis (VT), six had episodes of VT followed by arterial thrombosis (AT) and eight had AT only. All 27 patients were less than 42 years of age; 22 had specific natural anticoagulant or fibrinolytic deficiencies: antithrombin III (nine patients), protein C (eight patients), protein S (three patients), heparin cofactor II (two patients), tissue plasminogen activator release (one patient) and mixed antithrombin III and protein S (one patient). The remaining five patients had recurrent thrombotic events associated with resistance to heparin anticoagulation, but no established laboratory diagnosis. Clotting complications included recurrent VT, pulmonary embolism, multiple failed arterial procedures and lower extremity amputation. The remaining 22 patients (mean age of 53 years, range of 46 to 63 years), 12 with VT and ten with AT, did not have laboratory evidence of hypercoagulability and none had recurrent vascular occlusions. All these patients were successfully treated by conventional therapy without any additional thrombotic events during the follow-up period. Young adults with spontaneous thrombotic events should be screened for possible hypercoagulable states. Additionally, these young patients need further evaluation and treatment of cardiovascular risk factors. Those with premature atherosclerosis have an especially poor prognosis despite surgical intervention and anticoagulant therapy.
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PMID:Hypercoagulable states as an evolving risk for spontaneous venous and arterial thrombosis. 792 7

This article has stressed the common hereditary and acquired blood protein defects associated with thrombosis. The commonest hereditary defects appear to be antithrombin, protein C, and protein S deficiency, and the commonest acquired defects are anticardiolipin antibodies and the lupus anticoagulant. Therefore these are the defects that should first be looked for in an individual with unexplained thrombosis. If these commoner defects are not found, the rarer defects, including HC-II, plasminogen or t-PA deficiency, dysfibrinogenemia, or elevated PAI-1, should next be sought. The incidence of activated protein C cofactor deficiency is not yet clear but may also represent a common defect. Likewise, PAI-1 defects may, with time, be shown to be quite common. The importance of finding these defects has significant implications for therapy of the individual patient and for institution of family studies to identify, inform, and possibly treat others at risk. It is expected that as knowledge of hemostasis expands, more hereditary and acquired defects, such as elevated lipoprotein (a) or defects of extrinsic (tissue factor) pathway inhibitor may be associated with enhanced risks of thrombosis.
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PMID:Hypercoagulability and thrombosis. 817 Feb 63


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