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Query: UNIPROT:P00750 (PLA)
 16,800 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Cross-linked hybrid oligomers of fibrinogen and fibrin are found in plasma from fibrinaemic patients and normal individuals as well as in preparations of purified human fibrinogen. The present study was undertaken to see if such hybrid oligomers have the same stimulatory effect on tissue plasminogen activator (t-PA) conversion of plasminogen as do polymeric and monomeric fibrin. Hybrid oligomeric fibrin(ogen) material was provided by subjecting purified human fibrinogen to gel filtration in urea-containing buffer at pH 5.6. Well separated fractions of hybrid oligomeric material and monomeric fibrinogen were thus obtained. Some of this material was converted to soluble polymeric or monomeric fibrin using insolubilized thrombin. Hybrid polymeric fibrin, polymeric fibrin or monomeric fibrin were then added to citrated, normal plasma to 2.5 or 5 per cent of the plasma fibrinogen concentration. The added material was kept in solution by plasma fibrinogen. The "COA-SET Fibrin Monomer Test" (Kabi,Stocholm,Sweden), based on the ability of fibrin monomers to enhance t-PA mediated plasminogen-plasmin conversion, was used to compare the potential stimulatory effect of the preparations above. The results led to the following conclusions: 1) Cross-linked, soluble fibrin(ogen) hybrid polymers in a concentration of 5 per cent of plasma fibrinogen concentration (w/w) do not stimulate t-PA. 2) Thrombin conversion of the fibrin-fibrinogen hybrid material resulted in an increase in the rate of t-PA mediated plasminogen conversion, corresponding to the one observed with equivalent (w/w) amounts of fibrin monomers. Compared on a mole to mole basis, fibrin oligomers are more powerful than fibrin monomers as stimulators of t-PA activity.
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PMID:Soluble, cross-linked fibrin(ogen) hybrid oligomers do not stimulate t-PA conversion of plasminogen. 141 94

The ability of the COA-SET Fibrin monomer (COA-SET FM) test to detect soluble fibrin was evaluated by comparing the results of the COA-SET FM test with fibrinopeptide A (FPA) determinations following thrombin incubation of plasma or whole blood. In addition, two semiquantitative tests (erythrocytes-agglutination test (FM-test) and ethanol gelation test (EGT] were included in the study. Under the experimental conditions used, the COA-SET FM test proved less sensitive than the FPA-assay. There was a strong correlation between the results obtained by the two tests (r = 0.86, p = 0.0001). When solely regarding low levels of soluble fibrin, however, the correlation was weaker (r = 0.59, p = 0.0003). The FM-test was less sensitive than the COA-SET FM test, but more sensitive than EGT at normal and low fibrinogen concentrations. At high fibrinogen concentrations, however, EGT proved more sensitive than the FM-test. Knowing that 1-2 moles of FPA are released per mole of fibrin monomers formed, a discrepancy was observed between the FPA concentrations and the fibrin monomer concentrations as determined by the COA-SET FM test, the FPA levels being 2-25 times higher than the fibrin monomer levels. The discrepancy was greatest at incipient fibrinogen-fibrin transformation and at high plasma fibrinogen levels. This may suggest that fibrinogen in some way interfered with the stimulating effect of fibrin on the t-PA catalyzed activation of plasminogen, the principle upon which the COA-SET FM test is based.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Comparison of methods for detecting soluble fibrin in plasma. An in vitro study. 232 70

Fibrinolytic activity and tissue plasminogen activator (t-PA) level were measured in 33 healthy individuals prior to and after fibrinolytic system stimulation (i.e. a ten-minute venous stasis). Fibrinolytic activity was measured with the aid of euglobin lysis time, and lysis test on the fibrin plates (in own modification). Tissue plasminogen activator concentration was assayed spectrophotometrically with the COA-SET t-PA (Kabi Vitrum). No fibrinolytic activity of plasma specimens taken before the venous stasis was noted during fibrin lysis plate test whereas it was seen in 13 subjects after the venous stasis. Fibrinolytic activity of the plasma euglobins, measured as a surface on fibrin plates, increased significantly after the venous stasis in both sexes (by 35.5 mm2 on the average, i.e. by 51%). It was more marked in men than in women both prior to and after venous stasis (by 10.9% and 19.0%, respectively). A time of plasma euglobin lysis was shorter after venous stasis (by 110 minutes, on the average). There was no significant difference between the sexes. Tissue plasminogen activator concentration increased by 5.8 times (from 1.7 IU/ml to 9.9 IU/ml) after the stasis. Correlation between t-PA concentrations and fibrinolytic activity, measured on the fibrin plates, was highly positive. No such a correlation existed between t-PA concentrations and the time of euglobin lysis. The obtained results indicate variety of assessments of fibrinolytic system activity.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:[Fibrinolytic activity and tissue plasminogen activator level in healthy individuals prior to and after a ten-minute venous stasis]. 836 5

Radiologic contrast media may influence processes of hemostasis resulting in increased thrombotic or bleeding tendency. A number of clinical case reports suggest that the use of nonionic contrast media is associated with thrombotic complications. In vitro studies have indicated that nonionic contrast media may induce generation of thrombin in blood whereas ionic contrast agents do not show such an effect. Not much is known about the effects of contrast media on the coagulation and fibrinolytic systems in vivo. The aim of this study was to evaluate the systemic effects of markers for activation of fibrinolysis with a nonionic contrast medium (Iopromid/Ultravist-300/Schering AG) and ionic contrast medium (Uropolinum, Polfa) in 82 patients undergoing angiography. We measured tissue plasminogen activator (t-PA) and tissue plasminogen activator inhibitor (PAI), using COA-SET, t-PA and COA-TEST PAI (Chromogenix). Fibrinogen concentration and euglobulin lysis time (ELT) were also estimated. Both contrast agents caused a significant decrease in fibrinogen concentrations. A marked difference was seen for PAI activity. A statistically significant increase was seen in the Iopromid group and no statistically significant rise was seen in the Uropolinum group. t-PA activity remained virtually unchanged in both groups. ELT has been significantly prolonged in patients who received Iopromid but not in those who received Uropolinum. It is likely that nonionic contrast medium could release PAI from platelets and endothelial cells. The changes in fibrinolysis may result from endothelial cell dysfunction.
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PMID:Effect of nonionic and ionic contrast media on fibrinolysis in patients undergoing angiography. 911 70