Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:2.3.1.108 (TAT)
 2,389 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The occurrence of a "rebound hypercoagulable state" in patients after dicontinuation of oral anticoagulants is still a matter of debate and no definite recommendation can be made on the best procedure for anticoagulant withdrawal. The present study investigated the changes in the levels of markers of activated blood coagulation in 32 patients (pts) in whom warfarin treatment (for venous thromboembolic disease) was randomly withdrawn abruptly (n = 17, group A) or gradually (n = 15, group B: 2/3 of initial dose the 1st week, 1/3 the 2nd weeks and nothing from the 3rd week on). Blood was sampled at baseline, once a week for the first three weeks and after 2 months. At the 1st week group A had significantly higher F1+2 and TAT values (p < 0.001); at the 2nd week F1+2 levels remained higher (p < 0.05) though INR values were not different from those of group B. After baseline, higher than normal F1+2 levels were recorded in 32/66 (48%) controls in group A vs 15/60 (25%) in group B (p < 0.01); at the 2nd week, 10/17 (59%) patients in group A vs 1/15 (7%) in group B still had higher than normal F1+2 levels (p < 0.01). The values of areas under curve (AUC) and maximum concentrations of all variables were not statistically different in the two groups; however, very high levels were observed in a few cases of group A. Thrombotic events (one DVT recurrence and one thrombophlebitis in a varicose vein) occurred in 2 pts of group A, both with high F1+2 and TAT AUC values.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Activation of blood coagulation after abrupt or stepwise withdrawal of oral anticoagulants--a prospective study. 783 56

This study was designed to elucidate the participation of endothelin-1(ET-1) in vivo and in vitro coagulation. The microvascular hemodynamic changes in terms of intravascular thrombus formation in rat mesentery induced by the superfusion of ET-1 (0.5, 1 and 2 pmol) were visualized by an intravital microscope system assisted by television-video tape recorder system. In addition to vasoconstriction we observed the blockade of circulation by clumps resembling thrombus in a dose dependent fashion by ET-1. Thrombus formation could be attenuated by pretreatment with superfusion of 3.8% Na citrate solution but not by the prior superfusion of 1 to 3 ng of nitroglycerine. Thrombus formation was found after the administration of 10 microliters of CaCl2 (100 nM) solution in Na citrate (3.8%, 20 microliters) and ET-1 treated field. In vitro study, a dose dependent increase in TAT (thrombin-antithrombin complexes) and decrease in AT III (antithrombin III) (%) activity, the prolongation of PT (prothrombin time) and APTT (activated partial thromboplastin time) was found by administering ET-1 immediately in native (unanticoagulated) blood in silicon coated test tubes (p < 0.05; n = 6). However in citrated blood, TAT complexes, AT III (%) activity, PT and APTT were not significantly changed after administration of the same doses of ET-1 (p > 0.05; n = 6). Therefore, this study suggested that endothelin-1 caused intravascular thrombosis and enhanced intra test tube coagulation which could be attenuated by blocking ionic calcium.
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PMID:Coagulation in vivo microcirculation and in vitro caused by endothelin-1. 830 59

Thrombus formation is recognized pathologically in the affected arteries and is supposed to play a major role in the pathogenesis of Takayasu's arteritis; however, hemostatic conditions in this disorder have not been elucidated fully. We determined plasma levels of molecular markers for platelet activity (platelet factor 4; PF4, beta-thromboglobulin; beta TG), thrombotic status (thrombin-antithrombin III complex; TAT, fibrinopeptide A; FPA), fibrinolytic status (plasmin-alpha 2-plasmin inhibitor complex; PIC, D-dimer), and endothelial injury (von Willebrand factor antigen; vWF:Ag, thrombomodulin; TM) in 30 patients with Takayasu's arteritis and 20 age-matched control subjects. Plasma levels of PF4, beta TG, TAT, FPA and D-dimer, but not PIC, in patients with Takayasu's arteritis were substantially higher than those in normal control subjects. The levels of these markers were not different between the active and inactive stages of the disease. Plasma levels of vWF:Ag in patients with Takayasu's arteritis did not differ significantly from those in normal subjects, and plasma levels of TM were significantly lower than those in normal subjects. In patients with Takayasu's arteritis, platelet and coagulation activities are significantly increased, leading to hypercoagulable state and thrombus formation, although there is little, if any, endothelial damage.
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PMID:Hypercoagulable state in patients with Takayasu's arteritis. 872 10

Current designs of bileaflet mechanical heart valves put patients at an increased risk of thromboembolism. In particular, regurgitant flow through the b-datum line is associated with nonphysiologic flow characteristics such as elevated shear stresses, regions of recirculation, and increased mixing, all of which may promote thrombus formation. We have previously shown that passive flow control in the form of vortex generators mounted on the downstream leaflet surfaces can effectively diminish turbulent stresses. The objective of the current work is thus to determine the effect of vortex generators on the thromboembolic potential of the b-datum line leakage jet and to correlate that effect with the vortex generator-induced changes to the flow structure. Flow experiments were performed using a steady model of the transient b-datum line jet. These experiments encompassed flow visualization to gain an overall picture of the flow system, particle image velocimetry to quantify the flow field in detail, and in vitro experiments with human blood to quantify thrombus formation in response to the applied passive flow control. Thrombus formation was quantified over time by an assay for thrombin-antithrombin III (TAT III). In comparing results with and without vortex generators, significantly lower mean TAT III levels were observed at one time point for the case with vortex generators. Also, the TAT III growth rate of the case with vortex generators was significantly lower. While no differences in jet spreading were found with and without vortex generators, lower peak turbulent stresses were observed for the case with vortex generators. The results thus demonstrate the potential of applying passive flow control to cardiovascular hardware in order to mitigate the hemodynamic factors leading to thrombus formation.
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PMID:Reduction of procoagulant potential of b-datum leakage jet flow in bileaflet mechanical heart valves via application of vortex generator arrays. 2059 Feb 89