Search results for " Thrombin"
showing 10 items of 17 documents
Prothrombotic State Induced by Middle-Distance Endurance Exercise in Middle-Aged Athletes
2018
AbstractSince the impact of possible prothrombotic factors on blood coagulation resulting from exercise remains elusive, this study investigated the acute effects of middle-distance endurance running on blood coagulation parameters in middle-aged athletes. The study population consisted of 33 male endurance runners who were engaged in a 21.1 km run under competitive conditions. Blood samples were collected before the run, immediately after the run, and 3 hours after run completion. Samples were assessed for activated partial thromboplastin time (APTT), prothrombin time (PT), fibrinogen, D-dimer, factor VIII (FVIII), von Willebrand factor antigen (VWF:Ag), endogenous thrombin potential (area…
Treatment of acute venous thromboembolism with dabigatran or warfarin and pooled analysis
2014
Background— Dabigatran and warfarin have been compared for the treatment of acute venous thromboembolism (VTE) in a previous trial. We undertook this study to extend those findings. Methods and Results— In a randomized, double-blind, double-dummy trial of 2589 patients with acute VTE treated with low-molecular-weight or unfractionated heparin for 5 to 11 days, we compared dabigatran 150 mg twice daily with warfarin. The primary outcome, recurrent symptomatic, objectively confirmed VTE and related deaths during 6 months of treatment occurred in 30 of the 1279 dabigatran patients (2.3%) compared with 28 of the 1289 warfarin patients (2.2%; hazard ratio, 1.08; 95% confidence interval [CI], 0.…
Is it necessary to alter anticoagulation therapy for tooth extraction in patients taking direct oral anticoagulants?
2017
Background The number of patients using direct oral anticoagulants (DOACs) instead of vitamin K antagonists (VKA) is increasing and there is limited data on the safety of tooth extractions in patients taking DOACs. The aim of this study was to compare the amount of bleeding (AOB) and postoperative complications after tooth extractions between patients taking VKAs and patients taking DOACs without altering the anticoaguation therapy. Material and Methods The study consisted of four groups: Direct thrombin inhibitor group, factor Xa inhibitor group, warfarin group and a control group. A single tooth was extracted in each patient and routine coagulation test values were recorded prior to extra…
VITAMIN K-INDUCED MODIFICATION OF COAGULATION PHENOTYPE IN VKORC1 HOMOZYGOUS DEFICIENCY
2008
Summary. Background: Combined vitamin K-dependent clotting factor (VKCF) deficiency type 2 (VKCFD2) is a rare bleeding disorder caused by mutated vitamin K 2,3-epoxide reductase complex subunit 1 (VKORC1) gene. Methods and results: An Italian patient with moderate to severe bleeding tendency was genotyped, and found to be homozygous for the unique VKORC1 mutation (Arg98Trp) so far detected in VKCFD2. The activity levels of VKCFs were differentially reduced, and inversely related to the previously estimated affinity of procoagulant factor propeptides for the γ-carboxylase. The normal (factor IX) or reduced antigen levels (other VKCFs) produced a gradient in specific activities. Vitamin K su…
Evidence for the presence of functional protease activated receptor 4 (PAR4) in the rat colon
2004
Background and aims: Protease activated receptors (PARs) have been postulated to play a role during intestinal inflammation. The presence and role played by PAR4 in gastrointestinal functions have not been fully clarified. The aims of this study were: (i) to examine expression of PAR4 in rat proximal colon; (ii) to determine the mechanical effects induced by PAR4 activation in longitudinal muscle; and (iii) to characterise the underlying mechanisms. Methods: PAR4 expression was determined by reverse transcription-polymerase chain reaction (RT-PCR) and immunohistochemistry. Mechanical activity was recorded as changes in isometric tension. Results: A PCR product corresponding to the predicted…
Interaction of inflammation, thrombosis, aspirin and enoxaparin in CNS experimental antiphospholipid syndrome
2008
Experimental antiphospholipid syndrome (eAPS) induced by immunization with beta(2)-glycoprotein I (beta(2)-GPI) causes behavioral hyperactivity. We assessed the role of thrombotic and inflammatory perivascular factors and standard APS therapies for CNS manifestations. Groups of mice (n=10 per group) were immunized once with beta(2)-GPI (eAPS) or adjuvant (controls) and treated daily from 1 month after immunization with either sham injections, aspirin (1.2 mg/kg) or enoxaparin (1 mg/kg) for 3 months. Serum antiphospholipid antibodies (aPL) and brain levels of tissue necrosis factor-alpha (TNF-alpha) and prostaglandin E (PGE) were then measured by ELISA and thrombin inhibitors by immunoblot. …
L’IMPIEGO CLINICO DI UNA NUOVA CLASSE DI FARMACI ANTICOAGULANTI: GLI INIBITORI DIRETTI DELLA TROMBINA
2006
The coagulation cascade, and particularly thrombin, plays a very important role in arterial and venous thrombosis. Thereby, it is clear that thrombin inactivation is an optimal strategy for thrombotic disease prevention and treatment. The direct thrombin inhibitors are a new class of anticoagulant drugs directly binding thrombin and blocking its interaction with fibrinogen. The group of direct thrombin inhibitors includes recombinant hirudin (lepirudin and desirudin), bivalirudin, melagatran and its oral precursor, ximelagatran, argotraban and dabigatran. These drugs have several advantages compared to other anticoagulant drugs, and the particular pharmacokinetic properties of some of them …
Prothrombinase-Induced Clotting Time Assay for Determination of the Anticoagulant Effects of Unfractionated and Low-Molecular-Weight Heparins, Fondap…
2008
The prothrombinase-induced clotting time assay (PiCT, Pentapharm, Basel, Switzerland) is a clotting assay sensitive to factor Xa and factor IIa inhibitors. It is based on the addition of factor Xa and snake venom RVV-V (Russell viper venom factor V activator) specifically activating factor V and phospholipids to platelet-poor plasma. Following an incubation time, the mixture is recalcified and the clotting time is determined. An almost linear dose-response and high sensitivity of the assay for unfractionated heparin (UFH), low-molecular-weight heparins (LMWHs), r-hirudin, and argatroban was found. Fondaparinux showed a nonlinear dose-response. By using ex vivo samples, the following Pearson…
Signal transduction pathways involved in the mechanical responses to protease-activated receptors in rat colon.
2002
Recording simultaneously in vitro the changes of endoluminal pressure (index of circular muscle activity) and isometric tension (index of longitudinal muscle activity), we examined the mechanisms responsible for the apamin-sensitive relaxant and contractile responses induced by protease-activated receptor (PAR)-1 and PAR-2 activating peptides, SFLLRN-NH2 and SLIGRL-NH2, respectively, in rat colon. In the circular muscle, the inhibitory effects of SFLLRN-NH2 and SLIGRL-NH2 were significantly reduced by ryanodine, an inhibitor of Ca2+ release from the sarcoplasmic reticulum, but unaffected by 1-[6-[[17beta-methoxyestra-1,3,5(10)-trien-17-yl]amino]hexyl]-1H-pyrrole-2,5-dione (U73122), a phosph…
Coagulation and fibrosis in chronic liver disease.
2008
In the hepatic tissue repair mechanism, hepatic stellate cells (HSCs) are recruited at the site of injury and their changes reflect paracrine stimulation by all neighbouring cell types, including sinusoidal endothelial cells, Kupffer cells, hepatocytes, platelets and leucocytes. Thrombin converts circulating fibrinogen to fibrin, promotes platelet aggregation, is a potent activator of endothelial cells, acts as a chemoattractant for inflammatory cells and is a mitogen and chemoattractant for fibroblasts and vascular smooth muscle cells. Most of the cellular effects elicited by thrombin are mediated via a family of widely expressed G-protein-coupled receptors termed protease activated recept…