Thromb Haemostasis
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A deletion/insertion polymorphism (4G or 5G) in the promoter of the plasminogen activator inhibitor type 1 gene has been suggested to be involved in regulation of the synthesis of the inhibitor, the 4G allele being associated with enhanced gene expression. A relationship between 4G/5G polymorphism and PAI-1 levels was found in patients with cardiovascular and metabolic diseases, but not in healthy subjects. In the present work we studied the distribution of PAI-1 4G/5G genotype and its relation to fibrinolytic capacity in 70 unrelated patients with deep vein thrombosis. ⋯ Moreover, the prevalence of PAI-1 induced hypofibrinolysis was strongly related to PAI-1 polymorphism, since it was significantly lower in 5G homozygous patients (28.6%) than in both 4G/5G carriers (55.3%, p <0.001) and 4G homozygous patients (57.9%, p <0.001). In conclusion, in patients with deep vein thrombosis the 4G polymorphism of PAI-1 gene promoter may influence the expression of PAI-1 and it should be taken into consideration as a facilitating condition for pathological fibrinolysis together with other environmental and genetic factors. Whether this has any significance in regard to the pathogenesis of venous thrombosis remains to be proven.
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The recent publication of two large trials of secondary prevention of coronary artery disease with oral anticoagulants (WARIS and ASPECT) has caused a revival of the interest for this antithrombotic therapy in a clinical setting where the use of aspirin is common medical practice. Despite this, the preferential use of aspirin has been supported by an American cost-effectiveness analysis (JAMA 1995; 273: 965). ⋯ Preference of aspirin vs. oral anticoagulants in a pharmaco-economical perspective is highly dependent on the geographical situation whereupon calculations are based. On a pure cost-effectiveness basis, and in the absence of data of direct comparisons between aspirin alone versus I.N.R.-adjusted oral anticoagulants, the latter are not more expensive than aspirin in Italy and, by cost comparisons, in other European countries in the setting of post-myocardial infarction.
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Randomized Controlled Trial Clinical Trial
Recombinant tumor necrosis factor receptor p75 fusion protein (TNFR:Fc) alters endotoxin-induced activation of the kinin, fibrinolytic, and coagulation systems in normal humans.
The effects of inhibition of tumor necrosis factor (TNF) on cell and protease activation were evaluated in 18 normal volunteers given endotoxin (4 ng/kg, i.v.) after an infusion of low (10 mg/m2 i.v., n = 6) or high dose (60 mg/m2 i.v., n = 6) recombinant human dimeric TNF receptor protein (TNFR:Fc) or its vehicle (placebo n = 6). Activation of the coagulation system occurred by 2 h in the TNFR:Fc vehicle-placebo group manifested by decreased prekallikrein functional levels and increased levels of prothrombin F1+2 fragments (p < 0.0001). High or low dose TNFR:Fc delayed the fall in prekallikrein functional levels by 1 h and 4 h, respectively (p < 0.0002), but did not inhibit the increase in circulating levels of prothrombin F1+2 fragments. ⋯ Increased levels of neutrophil elastase were attenuated by low and high dose TNFR:Fc (p < 0.001). These results suggest that although TNF is functionally linked to the activation of endothelium, neutrophils, coagulation, and fibrinolysis, alternative pathways are present in vivo that result in activation of the kallikrein-kinin system after endotoxin-induced TNF release. These alternative pathways may limit some of the anti-inflammatory effects of TNFR:Fc.
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Multicenter Study Clinical Trial
Low-dose oral vitamin K reliably reverses over-anticoagulation due to warfarin.
Patients receiving long-term warfarin frequently develop asymptomatic excessive prolongation of their international normalized ratio (INR) results. The most appropriate management strategy in these patients is unknown. This prospective cohort study was designed to address whether 1 mg of oral vitamin K effectively reduces the INR value of such patients. ⋯ In patients receiving warfarin who have asymptomatic excessive prolongations in their INR results, 1 mg of oral vitamin K reliably reduces the INR to the therapeutic range within 24 h. This therapy is more convenient, less expensive, and might be safer than parenteral vitamin K. Thus, it should be considered in all non-bleeding patients receiving warfarin, who present with INR results of 4.5 to 9.5.
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Comparative Study
Significant correlations between tissue factor and thrombin markers in trauma and septic patients with disseminated intravascular coagulation.
To determine the role of plasma tissue factor on disseminated intravascular coagulation (DIC) in trauma and septic patients, and also to investigate the relationships between tissue factor and various thrombin markers, we made a prospective cohort study. Forty trauma patients and 20 patients with sepsis were classified into subgroups according to the complication of DIC. Plasma tissue factor antigen concentration (tissue factor), prothrombin fragment F1+2 (PF1+2), thrombin antithrombin complex (TAT), fibrinopeptide A (FPA), and D-dimer were measured on the day of admission (day 0), and on days 1, 2, 3, and 4 after admission. ⋯ In patients with sepsis, tissue factor levels on days 0 through 4 in the non-DIC group showed markedly higher values than those in the control patients (135 +/- 8 pg/ml). Significant correlations between tissue factor and PF1+2, TAT, FPA, and D-dimer were observed in the DIC patients, however, no such correlations were found in the non-DIC patients. These results suggest that elevated plasma tissue factor in patients with trauma and sepsis gives rise to thrombin generation, followed by intravascular coagulation.