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

Human plasma contains an inhibitor of tissue factor-initiated coagulation known as the lipoprotein-associated coagulation inhibitor (LACI) or also known as the extrinsic pathway inhibitor (EPI). A competitive fluorescent immunoassay was developed to measure the plasma concentration of LACI in samples from normal individuals and patients with a variety of diseases. The LACI concentration in an adult control population varied from 60% to 160% of the mean with a mean value corresponding to 89 ng/mL or 2.25 nmol/L. Plasma LACI levels were not decreased in patients with severe chronic hepatic failure, warfarin therapy, primary pulmonary hypertension, thrombosis, or the lupus anticoagulant. Plasma LACI antigen was decreased in some, but not all patients with gram-negative bacteremia and evidence for disseminated intravascular coagulation. Plasma LACI levels were elevated in women undergoing the early stages of labor (29%), in patients receiving intravenous tissue-type plasminogen activator (45%), and in patients receiving intravenous heparin (375%). A radioligand blot of the pre- and post-heparin plasma samples shows the increase to be in a 40-Kd form of LACI. Very low levels of plasma LACI antigen were found in patients with homozygous abetalipoproteinemia and hypobetalipoproteinemia, diseases associated with low plasma levels of apolipoprotein B containing lipoproteins. Following the injection of heparin into one patient with homozygous abetalipoproteinemia, the plasma LACI antigen level increased to a level comparable with that in normal individuals after heparin treatment.
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PMID:Plasma antigen levels of the lipoprotein-associated coagulation inhibitor in patient samples. 207 76

Although the mechanisms involved in the pathophysiology of primary pulmonary hypertension have not yet been delineated, thrombosis has been implicated. This study was designed to determine whether thrombin activity as reflected by plasma concentrations of fibrinopeptide A (FPA), a marker of the action of thrombin on fibrinogen, is increased in patients with primary pulmonary hypertension. To evaluate fibrinolytic activity, we measured plasma concentrations of tissue-type plasminogen activator, plasminogen activator inhibitor-1, and cross-linked fibrin degradation products. We studied 31 patients with primary pulmonary hypertension. Plasma FPA concentrations measured by radioimmunoassay, were elevated to 87.4 +/- 36.9 ng/ml (mean +/- SEM). Fifteen minutes after administration of heparin (5,000 U), FPA concentrations decreased to 6.8 +/- 1.4 ng/ml (p less than 0.001 compared with preheparin levels). In 21 of 30 patients (70%), FPA concentrations after heparin administration were less than half the preheparin levels, a response consistent with inhibition of thrombin by heparin and the short half-life of FPA. Despite evidence for marked thrombin activity, plasma concentrations of cross-linked fibrin degradation products were normal in all but four patients. Plasminogen activator inhibitor-1 activity was elevated in 19 of the 27 patients in whom it was measured, potentially limiting the fibrinolytic response. The elevations of FPA indicate that thrombin activity is increased in vivo in patients with primary pulmonary hypertension. Thus, sequential assays of plasma markers of thrombosis and fibrinolysis in vivo may help identify those patients who may benefit from treatment with anticoagulants.
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PMID:Fibrinopeptide A levels indicative of pulmonary vascular thrombosis in patients with primary pulmonary hypertension. 239 5

We measured fibrinogen levels as well as the fibrinolytic parameters tissue-type plasminogen activator (t-PA) and plasminogen activator inhibitor 1 (PAI-1) in plasma samples obtained at basal conditions and after stimulating the fibrinolytic system by venous occlusion (VO). Samples were taken from patients with primary pulmonary hypertension (PPH), with secondary thromboembolic pulmonary hypertension (SPHTH), with secondary pulmonary hypertension due to congenital heart disease with Eisenmenger's reaction (SPHCD), and from healthy control individuals (CON). Fibrinogen levels were not significantly different between the groups with PPH and SPHTH or between SPHCD and CON. The latter groups, however, exhibited significantly lower fibrinogen plasma levels compared with PPH or SPHTH (p < 0.01). Basal plasma levels of t-PA antigen, t-PA activity, and PAI-1 activity, respectively, did not differ significantly between the study groups. After VO, mean t-PA activity levels increased to a higher extent in control subjects compared with patients with PPH, or SPHTH, or SPHCD, with significant differences only between CON and SPHTH or CON and PPH (p < 0.03). Patients with PPH and SPHTH exhibit both increased fibrinogen plasma levels and a diminished fibrinolytic response compared with healthy subjects. Moreover, the fibrinogen plasma levels in patients with SPHCD are in normal range, and the fibrinolytic response is similar to CON compared with PPH and SPHTH, thus indicating the existence of a comparable prothrombotic situation in patients with PPH and SPHTH.
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PMID:Fibrinogen, t-PA, and PAI-1 plasma levels in patients with pulmonary hypertension. 792 65

Antibodies to fibrin-bound tissue plasminogen activator (tPA) have been found in autoimmune diseases with vascular injury, such as systemic lupus erythematosus and scleroderma. The purpose of this study was to determine whether patients with primary pulmonary hypertension (PPH) have an immunogenetically determined response to fibrin-bound tPA. Antibodies to fibrin-bound tPA were determined in three patient groups: 45 adults with PPH, 41 children with PPH, and 40 children with anatomically large congenital pulmonary to systemic communications (PHT+shunt). The frequencies of the HLA class II (DRB1,3,4,5, and -DQB1) alleles in these three patient groups were compared with those of 51 healthy Caucasian control subjects. Fibrin-bound tPA antibodies were found in four of 45 (9%) adults with PPH, four of 41 (10%) children with PPH, and one of 40 (2.5%) children with PHT-shunt. HLA class II typing, which was available for seven of nine Caucasians with fibrin-bound tPA antibodies, revealed that six of seven (86%) patients typed HLA-DQ7 (DQB1*0301) and one typed HLA-DQ6. The 86% frequency of HLA-DQ7 in the antibody positive patients was significant compared with the 29% frequency in the healthy control subjects (p = 0.007, p corrected [pc] = 0.05, OR = 14.4). Of interest, these antibody-positive patients, although lacking antiphospholipid antibodies, shared an amino acid epitope, common to HLA-DQB1*06,07 and 08 subtypes, which was previously reported to be associated with the lupus anticoagulant. In conclusion, antibodies to fibrin-bound tPA and HLA-DQ7, and possibly the same epitope associated with the lupus anticoagulant, defined a small subset of children and adults with PPH.
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PMID:Primary pulmonary hypertension, tissue plasminogen activator antibodies, and HLA-DQ7. 900 24

The aim of the study was elucidation of hemostatic effects of low-molecular heparin Flaxiparin in patients with primary pulmonary hypertension (PPH). 10 PPH patients (mean age 39.0 (+)- 3.2 years, mean history of the disease 5.1 (+)- 0.9 years) were treated up to 6 months. For the first month Flaxiparin was injected in therapeutic doses 15,000 AXa ICU, twice a day. The next 5 months prophylactic doses were administered twice a day (7,500 AXa ICU). D-dimer, fragment 1 + 2, complex thrombin-antithrombin, beta-thromboglobulin, protein C, antithrombin III, antigen of tissue plasminogen activator and inhibitor of tissue plasminogen activator of type I, activity of the latter were measured before the treatment, after the therapeutic and prophylactic courses, 6 months after the treatment. Initially, the patients had procoagulative hemostatic disorders. i.e. activation of blood coagulation; fibrinolytic system was also affected. In the course of Flaxiparin therapy blood coagulation and fibrinolysis improved significantly. However, the effect was not persistent after the drug discontinuation. Flaxiparin can be recommended for treatment of PPH.
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PMID:[The effect of long-term Fraxiparin treatment on hemostasis in patients with primary pulmonary hypertension]. 941 32

Patients with primary pulmonary hypertension (PPH) benefit from treatment with anticoagulants, and histological findings suggest that in situ thrombosis of pulmonary vessels contributes to the pathogenesis of this disease. The mechanisms that cause a hypercoagulable state in the pulmonary vascular bed have not been fully investigated. This study compared plasminogen plasma activity, protein C and protein S plasma activities, fibrinogen and fibrin degradation products (FGDP and FBDP, respectively), von Willebrand factor antigen (vWF-Ag), prothrombin fragment F1.2, thrombin-antithrombin complexes (TAT), tissue plasminogen activator (tPA), and plasminogen activator inhibitor (PAI) in 16 patients with PPH and in 16 healthy volunteers. In a subset of the PPH patients, these variables were also compared in simultaneously-obtained mixed-venous and arterial blood samples. Proteins C and S, FGDP, FBDP, and plasminogen levels as well as plasma concentrations of prothrombin fragment F1.2 and TAT were normal in the 16 patients with PPH. In contrast, the plasma activity of PAI was significantly elevated (p<0.0001). Arterial PAI levels were considerably higher than mixed venous PAI levels (p=0.0018), which may reflect intrapulmonary production. Furthermore, vWF-Ag levels were significantly elevated (p<0.0001), but there was no significant difference between mixed-venous and arterial blood. These data, on the whole, do not suggest increased thrombin activity in patients with primary pulmonary hypertension. However, the markedly elevated levels of plasminogen activator inhibitor as well as its transpulmonary gradient may provide a clue to locally impaired fibrinolysis in the pulmonary vascular bed.
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PMID:Plasma coagulation profiles in patients with severe primary pulmonary hypertension. 987 7

Primary pulmonary hypertension (PPH) is a rare disorder, with marked in-situ thrombosis of small pulmonary vessels occurring primarily in adult women. We investigated whether differences in the plasmin- and thrombin activation system are associated with the predominate affection of females. Plasma levels of plasminogen activator inhibitor type 1 (PAI-1), tissue-type plasminogen activator (t-PA), fibrinogen, thrombin-antithrombin (TAT) complexes, and prothrombin fragments (F1.2) were measured at baseline and after standardized venous occlusion (VO) in patients with PPH (24 female, 9 male). At baseline, females showed significant higher TAT levels (p = 0.05), higher t-PA antigen levels (p = 0.01) and higher fibrinogen levels (p = 0.03) with positive correlation to mean pulmonary artery pressure (mPAP), as well as nonsignificant lower t-PA activity, higher PAI-1 antigen and activity and F1.2 levels. After VO, females showed a significantly blunted increase in t-PA antigen (p = 0.01) and t-PA activity (p = 0.001), correlating with mPAP, as well as increased PAI-1 activity (p = 0.05). We hypothesize, that the observed presence of gender differences in the plasmin- and thrombin activation system in PPH leading to an antifibrinolytic/prothrombotic state might, in part, explain the female predominant incidence of this disease.
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PMID:Impairment of the plasmin activation system in primary pulmonary hypertension: evidence for gender differences. 1152 3

The pathophysiology of primary pulmonary hypertension (PPH) remains poorly understood. Vascular wall remodeling and endothelial dysfunction reflected by modifications in plasma fibrinolytic proteins and von Willebrand factor have been well documented in PPH. We hypothesize that endothelial mediators, produced in excess in PPH patients, may stimulate migrating mononuclear cells and thereby modulate alveolar macrophage function; in particular, the plasminogen activation system. Components of the fibrinolytic system were therefore studied in plasma, blood monocytes and alveolar macrophages obtained from bronchoalveolar lavage in 10 patients with PPH and in four controls. Compared with controls, PPH patients had elevated plasma levels of tissue-type plasminogen activator (15.6 +/- 9.9 versus 5.5 +/- 3 ng/ml) and plasminogen activator inhibitor-1 (27.8 +/- 23 versus 16.4 +/- 12 ng/ml). In contrast, binding and activation of plasminogen by single-chain urokinase-type plasminogen activator (scu-PA) at the surface of blood monocytes and alveolar macrophages were not different from those of control values. Dissociation constants (K(d)) for binding of scu-PA and plasminogen to alveolar macrophages were similar in both PPH (4.7 +/- 1.5 and 0.88 +/- 0.3 micromol/l, respectively) and control (6.7 +/- 0.1 and 1.02 +/- 0.12 micromol/l, respectively) groups. These results indicate that in PPH patients the fibrinolytic activity of alveolar macrophages is normal, whereas endothelial fibrinolytic proteins are abnormally elevated in plasma.
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PMID:Plasminogen activation by blood monocytes and alveolar macrophages in primary pulmonary hypertension. 1213 69

Extracorporeal membrane oxygenation (ECMO) support is often used to support infants and children with hemodynamic or respiratory failure. One of the major obstacles of safely treating a child with ECMO is balancing the risk of hemorrhage with the potential for thrombus development. Managing thrombosis in the setting of ECMO is challenging and has no defined algorithm. The use of recombinant tissue-type plasminogen activator (tPA) for thrombolysis has been previously described in cases where thrombi have developed despite adequate anticoagulation. In such situations, the risk of hemorrhage must be carefully balanced with the benefit of dissolving the clot and reestablishing flow. We present a case of an infant who required ECMO because of severe primary pulmonary hypertension and subsequently developed a right atrial thrombus adjacent to the ECMO cannula. The patient was treated with tPA with immediate improvement but had fatal intracranial hemorrhage almost 3 days after the tPA was administered. In this report, we review the current literature on tPA use during ECMO support and suggest a rational approach.
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PMID:The use of recombinant tissue-type plasminogen activator in a newborn with an intracardiac thrombus developed during extracorporeal membrane oxygenation. 2200 44