Search results for "thrombin"
showing 10 items of 201 documents
Acquisition of Structure-guiding and Structure-forming Properties during Maturation from the Pro-silicatein to the Silicatein Form
2012
Silicateins are the key enzymes involved in the enzymatic polycondensation of the inorganic scaffold of the skeletal elements of the siliceous sponges, the spicules. The gene encoding pro-silicatein is inserted into the pCold TF vector, comprising the gene for the bacterial trigger factor. This hybrid gene is expressed in Escherichia coli and the synthesized fusion protein is purified. The fusion protein is split into the single proteins with thrombin by cleavage of the linker sequence present between the two proteins. At 23 °C, the 87 kDa trigger factor-pro-silicatein fusion protein is cleaved to the 51 kDa trigger factor and the 35 kDa pro-silicatein. The cleavage process proceeds and res…
Disseminated Intravascular Coagulation
1985
During the past decade, diffuse intravascular coagulation (DIC) has been one of the most intensively studied subjects in hematology. DIC is a dynamic pathologic process caused by the entrance of foreign material into the circulation, or by exposure to abnormal surfaces. The intravascular coagulation is triggered by activation of the clotting cascade with resultant generation of excess thrombin within the vascular system that leads to further activation of the coagulation system, shortened survival of certain hemostatic elements, deposition of fibrin in the microcirculation, and activation of the fibrinolytic system. Decreased levels of hemostatic factors, secondary fibrinolysis, and exhaust…
Successful management of heparin-induced thrombocytopenia using argatroban in a very old woman: a case report.
2012
Thrombosis due to heparin-induced thrombocytopenia (HIT) is rare but has a severe prognosis. Its management is not always easy, particularly in old patients with renal insufficiency. A 95-year-old woman was hospitalized for dyspnea. Curative treatment with unfractionated heparin was started because pulmonary embolism was suspected. Disseminated intravascular coagulation was then suspected because of thrombocytopenia, hypoprothrombinemia, hypofibrinogenemia, and a positive ethanol gelation test. The first immunoassay for HIT was negative. On the 12th day of hospitalization, bilateral cyanosis of the toes occurred associated with recent deep bilateral venous and arterial thrombosis at duplex …
Oxcarbazepine does not affect the anticoagulant activity of warfarin.
1992
The possible interaction of the antiepileptic drug oxcarbazepine (OCBZ) on the anticoagulant effect of warfarin was investigated in 10 healthy male volunteers. After reaching steady-state conditions by repeated administration of warfarin, the prothrombin time (Quick value) was assessed before and after single (600 mg) and multiple dosing (450 mg twice daily in 1 week) of OCBZ. In 7 of the 10 volunteers with evaluable data, the prothrombin time was not significantly different (paired t test) from baseline either after single (p = 0.299) or repeated dosing (p = 0.333), indicating that OCBZ does not interact to any relevant extent with the hypothrombinemic effect of warfarin.
Anti-inflammatory properties of simvastatin on leukocyte-endothelial cell interactions following hemorrhagic shock
2002
Background Hydroxymethylglutaryl coenzyme A (HMG-CoA) reductase inhibitors (statins) have been shown to lower serum cholesterol levels. Recent studies reported that statins have vasculoprotective effects independent of their cholesterol-lowering properties. We studied simvastatin for its ability to modulate leukocyte-endothelial cell interactions under acute inflammation following hemorrhage and reperfusion. Methods The effects of simvastatin on leukocyte-endothelial cell interactions were observed by intravital microscopy in the rat mesenteric microcirculation and by immunohistochemical analyzes. Simvastatin (50 μg/kg or 100 μg/kg) was administrated intraperitoneally 18 h before study. Inf…
The pleiotropic effects of antiplatelet therapies
2019
Percutaneous coronary intervention is the most often used method for coronary revascularization. Stenting restores blood perfusion to ischemic areas, but it also causes mechanical disruption of the atheromatous plaque and the nearby endothelium, stimulating the activation of platelets. In a similar way, platelets are activated by thrombin exposure in the setting of plaque rupture. The interaction between platelets, oxidative stress and inflammation is an important factor determining the extent and severity of vascular dysfunction observed in these settings. Platelets activated by the vessel trauma release inflammatory and mitogenic mediators into the vascular microenvironment, activating le…
Role of prothrombotic polymorphisms in successful or unsuccessful aging.
2011
The study of the genetic profile of centenarians aims to identify the genes and allelic variants which may influence a greater life expectancy and that can be considered as predisposing factors associated to the aging diseases, such as Alzheimer. Centenarians, that represent a cohort of selected survivors, show an hypercoagulability state characterised by striking signs of high coagulation enzyme activity, as directly assessed by the tested higher plasma level of some important factors involved in the haemostasis balance. Anyway, these individuals seem to have a reduced susceptibility to dementia, as well as to cardiovascular events. In this study we analyze the frequencies of Leiden Factor…
Gpibα Engagement Induces Activation of Human Platelet TF and Association with Constitutively Platelet Surface-Bound FVIIa
2019
The membranes of activated platelets assemble clotting protein complexes and enzymatic reactions needed for hemostasis and causing pathological thrombosis. Several reports have shown that human platelets contain TF, but controversies remain on the functional contributions of platelet TF to coagulation initiation. Here, we delineate the mechanism that converts platelet-associated TF to a procoagulant molecule. By combining specific inhibitors with human platelets from normal probands or patients with Glanzmann thrombasthenia or homozygous GPVI deficiency, we analyzed the procoagulant activation of platelet TF by biochemical methods, confocal microscopy, platelet adhesion under flow on VWF an…
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…
An Unexplained Congenital Disorder of Glycosylation-II in a Child with Neurohepatic Involvement, Hypercholesterolemia and Hypoceruloplasminemia
2017
We report on a 12-year-old adopted boy with psychomotor disability, absence seizures, and normal brain MRI. He showed increased (but initially, at 5 months, normal) serum cholesterol, increased alkaline phosphatases, transiently increased transaminases and hypoceruloplasminemia with normal serum and urinary copper. Blood levels of immunoglobulins, haptoglobin, antithrombin, and factor XI were normal. A type 2 serum transferrin isoelectrofocusing and hypoglycosylation of apoCIII pointed to a combined N- and O-glycosylation defect. Neither CDG panel analysis with 79 CDG-related genes, nor whole exome sequencing revealed the cause of this CDG. Whole genome sequencing was not performed since th…