Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P00750 (PLA)
 16,800 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Two promising novel recombinant tissue-type plasminogen activator (rt-PA) regimens for pulmonary embolism (PE) are being actively investigated: 100 mg/2 h as a continuous peripheral intravenous infusion, and bolus rt-PA, adjusted to weight, as a 2-min infusion. For deep venous thrombosis (DVT), less progress has been made in finding an optimal dosing regimen of rt-PA. Our mandate for the 1990s is to use the best possible thrombolytic dosing regimens in large clinical trials of PE and DVT. The primary objective of these planned clinical studies is to determine which patients with PE and DVT will benefit the most from thrombolysis followed by anticoagulation rather than anticoagulation alone.
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PMID:Thrombolysis in venous thromboembolism. An international perspective. 210 56

Plasma cross-linked fibrin-degradation products were analyzed using a D-dimer (DD) immunoassay in patients with deep vein thrombosis (DVT) or acute myocardial infarction (MI) treated with fibrinolytic therapy, and the results were correlated with clot lysis documented angiographically. In 13 patients with DVT, the mean DD concentration increased 10-fold (1,074 +/- 252 to 10,333 +/- 1,004 ng/ml) during therapy, but neither the peak level nor the DD concentration integrated over the course of therapy correlated with clot lysis. Since plasma DD can derive from degradation of soluble plasma fibrin as well as from thrombi, the contribution of the former was estimated by in vitro incubation of the pretreatment plasma with plasminogen activator. Subtraction of this value from the measured posttreatment DD concentration provided a "corrected" level that represented DD originating from lysis of thrombi. This modification resulted in improved correlation of DD levels with clot lysis. The mean corrected peak DD was higher in patients with successful thrombolysis (8,780 +/- 1,352 ng/ml) compared with patients without lysis (3,075 +/- 589 ng/ml, p less than 0.001). There was a moderate correlation between the volume of clot lysed and the corrected peak DD (r = 0.62) and a higher correlation with the corrected DD integrated over the course of treatment (r = 0.97). By contrast, the corrected DD concentrations were near zero in patients treated for MI with or without thrombolytic reperfusion, suggesting that fibrin in small coronary thrombi did not contribute significantly to total plasma DD during therapy.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Quantitation of venous clot lysis with the D-dimer immunoassay during fibrinolytic therapy requires correction for soluble fibrin degradation. 211 42

In a prospective, randomized controlled study, tissue plasminogen activator (t-PA) and tissue plasminogen activator antigen (t-PA:ag) were measured pre- and postoperatively in 40 consecutive patients undergoing total hip replacement. Patients received either a subcutaneous injection of low molecular weight heparin or placebo once daily. Deep vein thrombosis was diagnosed by bilateral phlebography. Patients who developed postoperative thromboembolic complications had significantly lower preoperative t-PA activity levels than patients who did not develop such complications. No difference was observed between the two groups with respect to t-PA:ag. Thromboprophylaxis with low molecular weight heparin did not cause any significant changes in t-PA activity and t-PA:ag. This study in high risk patients indicates that impaired fibrinolysis may be associated with development of thromboembolic complications after operation.
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PMID:Association between plasma levels of tissue plasminogen activator and postoperative deep vein thrombosis--influence of prophylaxis with a low molecular weight heparin. The Venous Thrombosis Group. 216 77

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

This study comprised 50 patients subjected to major abdominal surgery, of which 13 developed deep vein thrombosis (DVT) according to the 125I-fibrinogen test. Plasma was sampled preoperatively, for the specific analysis of tissue plasminogen activator (t-PA) before and during venous occlusion. The recently described fast t-PA inhibitor and plasmin alpha 2-antiplasmin complex (PAP) were also measured. The result of the laboratory analyses were correlated to the development of DVT. From the data obtained it is concluded that the evaluation of t-PA release during venous occlusion is a poor predictive factor for the occurrence of DVT after major abdominal surgery. The level of the t-PA inhibitor appears to be raised in these patients, but the values obtained in this material were not related to the development of postoperative DVT. Patients with elevated PAP levels, as shown previously, have a lesser tendency to develop postoperative DVT.
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PMID:Relationship between preoperative status of the fibrinolytic system and occurrence of deep vein thrombosis after major abdominal surgery. 241 Oct

An enzyme-linked immunosorbent assay for free tissue-type plasminogen activator (t-PA) in human blood was developed based on a murine monoclonal antibody directed against the active site of t-PA. The lower limit of sensitivity of the assay applied to plasma is 2 ng/mL for one-chain t-PA but only 100 ng/mL for two-chain t-PA. Free t-PA in plasma taken at rest was found in 6 of 21 healthy subjects (4.5 +/- 0.8 ng/mL, mean +/- SD) and increased to 14 +/- 7.0 ng/mL after venous occlusion in 18 of these individuals. A linear correlation between total t-PA and free t-PA was observed with r = 0.92 (n = 18) and a slope of 1.08, indicating that t-PA released from the vessel wall circulates in the blood as the one-chain form. In 16 of 18 patients with deep vein thrombosis, the increase of total t-PA antigen after venous occlusion was comparable to that observed in controls, but the free t-PA was significantly lower or undetectable. The present assay for free t-PA may be useful for the investigation of the release and inhibition of t-PA under physiological, pharmacological, or pathological conditions in humans.
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PMID:Measurement of free, one-chain tissue-type plasminogen activator in human plasma with an enzyme-linked immunosorbent assay based on an active site-specific murine monoclonal antibody. 243 30

We determined during the acute stage of myocardial infarction selected fibrinolysis variables (tissue-type plasminogen activator, intrinsic plasminogen activators, tissue-type plasminogen activator inhibition, C1-inactivator) and related the observed changes to changes in two acute phase reactants (C-reactive protein, fibrinogen). Acute myocardial injury induce significant increases in blood of tissue-type plasminogen activator inhibition (day one, p less than 0.05), C-reactive protein (day three, p less than 0.01), fibrinogen (day six, p less than 0.01), and C1-inactivator (day eight, p less than 0.01). Tissue-type plasminogen activator activity measured as C1-inactivator resistant fibrinolytic activity showed a minimum day two after the acute attack (p less than 0.01), whereas plasminogen activator activities arising from the intrinsic system of fibrinolysis remained constant. The observed changes did not parallel the occurrence of deep vein thrombosis indicated by a positive Tc-plasmin test (41% of the patients).
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PMID:Depression of tissue plasminogen activator (t-PA) activity and rise of t-PA inhibition and acute phase reactants in blood of patients with acute myocardial infarction (AMI). 244 88

Nine patients with, and 11 without, venous thromboses (DVT) from two families were studied. In family 1, four members with, and one without, DVT had t-PA activity below the lower limit of the controls (21.3 IU/ml, n = 19) after 20 min venous occlusion (VO). After VO t-PA antigen (t-PA:Ag) was below the lowest value of the controls (22.8 ng/ml) in all five cases with low t-PA activity. All the family members, both with and without thrombosis, had normal t-PA inhibitor activities (PAI). In family 2 t-PA activity after VO was low in three symptomatic and four asymptomatic family members. t-PA:Ag was also low in four of these. PAI level was normal in all but one family member. Mild type I von Willebrand's disease was discovered in four members of family 2. Deficient t-PA:Ag response was found in two of these. Antithrombin III, protein C and protein S were normal in both families. It is concluded that low fibrinolytic capacity, independent of PAI, is associated with familial DVT. Our data suggests autosomal dominant inheritance.
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PMID:Familial hypofibrinolysis and venous thrombosis. 249 18

A previously described bioimmunoassay for tissue-type plasminogen activator (t-PA) has been modified in terms of antibody concentration and conditions of incubation to achieve a sensitivity range of approximately 5-500 IU/L of t-PA. A similar assay has been developed for urinary-type plasminogen activator (U-PA), also known as urokinase (UK), achieving a sensitivity range of approximately 5-500 X 10(-1) IU/L. The direct sensitive t-PA assay has been demonstrated to be a quantitative alternative to the traditional semiquantitative euglobulin clot lysis time (ECLT) assay, with correlation coefficients of 0.967 and 0.914, depending on the laboratory where the ECLT was carried out. This assay has the added advantages of avoiding loss of t-PA or UK during the formation of the euglobulin fraction and of calibration in terms of International Standards for both t-PA and UK. With both these assays, it has been demonstrated that the enhanced fibrinolytic activity observed after exercise results from increased levels of t-PA while the level of UK in plasma remains unaltered. Free t-PA (10-60 IU/L) has been demonstrated in resting plasma, whereas the level of free UK activity was 50-100 IU/L. Venous occlusion of matched groups of subjects with and without deep venous thrombosis (DVT) showed a wide variation of response in t-PA levels in each group and no change in UK levels. There was no difference between the DVT and non-DVT groups, and this suggests that the notion of the "nonresponder" being more prone to thrombosis needs to be reexamined.
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PMID:Sensitive and direct assays for functionally active plasminogen activators (tissue-type and urokinase-type) in plasma. 250 7

The clinical and serological findings in 13 patients with myocardial infarction and antiphospholipid antibodies (the 'lupus anticoagulant', antibodies to cardiolipin, antibodies to phosphatidylethanolamine (one patient] seen by our unit and other units from 1984 to 1989, are presented (eight males and five females, ages ranging from 20 to 52 years). Five suffered myocardial infarction before the age of 30; four of these five were in their early 20s. Other risk factors such as excessive smoking (greater than 20 cigarettes a day) (two patients), long-term treatment with steroid (one) and use of oral contraceptives (one) were present. One patient had demonstrated a plasminogen activator deficiency and one a deficiency of protein C. Two patients developed myocardial infarction six to eight weeks after warfarin was discontinued for recurrent deep vein thrombosis. Six patients had SLE as defined by the revised 1982 criteria, three suffered from 'lupus-like' disease, while four patients conformed to a 'primary' antiphospholipid syndrome.
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PMID:Myocardial infarction and antiphospholipid antibodies in SLE and related disorders. 251 55


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