Blood coagulation & fibrinolysis : an international journal in haemostasis and thrombosis
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Blood Coagul. Fibrinolysis · Dec 2012
Plasma tissue-type plasminogen activator increases fibrinolytic activity of exogenous urokinase-type plasminogen activator.
The relationship between tissue-type plasminogen activator (tPA) and urokinase-type plasminogen activator (uPA) function is not fully understood. The aim of this study was to compare in vitro the fibrinolytic activity of tPA and uPA and evaluate their possible interaction. Blood coagulation and fibrinolysis were conducted by rotation thromboelastometry, whereas blood clotting was induced by CaCl2 and tissue factor and fibrinolysis additively by tPA and uPA. ⋯ Treating of blood with tranexamic acid (60 mmol/l) was followed by decreased fibrinolytic potential of both exogenous tPA and uPA, despite uPA by itself is known to be not sensitive to aminocaproic acids. Thus, uPA exerted stronger activity in blood but weaker activity in blood-free system, compared with tPA. Taking into account the intermolecular binding of uPA to tPA, it could be suggested that interaction of exogenous uPA with plasma-containing tPA provided amplification of fibrinolysis due to formation of uPA/tPA complex possessing high affinity to fibrin.
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Blood Coagul. Fibrinolysis · Dec 2012
Comparative StudyIn-vitro comparison of free oscillation rheometry (ReoRox) and rotational thromboelastometry (ROTEM) in trauma patients upon hospital admission.
Plasma-based assays do not provide accurate information on haemostatic resuscitation hence viscoelastic point-of-care haemostatic assays such as rotational thromboelastometry (ROTEM Delta, Pentapharm) are used to monitor coagulopathy in trauma patients. Free oscillation rheometry (FOR) is a new whole blood haemostatic assay that measures not only the clot-forming process but also the initial viscous phase; this could potentially be of value when assessing traumatic coagulopathy. A comparative analysis between FOR and ROTEM was therefore performed. ⋯ Interestingly, ROTEM EXTEM clotting time did not correlate with any of the FOR clot initiation parameters COT1, COT2 or COT2-1 of Fibscreen1. A correlation between ROTEM EXTEM and FIBTEM and FOR Fibscreen1 and Fibscreen2 clot formation and clot strength was found as was a significant correlation between lysis index after 60 min and ClotSR30. ROTEM EXTEM did not correlate with COT1, COT2 or COT2-1 of Fibscreen1 and this warrants further investigation.
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Blood Coagul. Fibrinolysis · Dec 2012
Postmenopausal women have an increased maximal platelet reactivity compared to men despite dual antiplatelet therapy.
Dual antiplatelet medication with acetylsalicylic acid (ASA) and clopidogrel is the main therapy for patients with stable coronary vessel disease (CVD) after percutaneous coronary intervention (PCI). Despite platelet inhibition subgroups of patients have been shown to exhibit an increase of risk for adverse cardiovascular events. The aim of our study was to elucidate the influence of sex on platelet reactivity in patients with CVD under medication with ASA and clopidogrel. ⋯ A multivariate linear regression model revealed female sex to be a significant prognostic marker for an increased TRAP-induced platelet reactivity, independent of the ASA and clopidogrel-associated platelet function inhibition. Sex differences did not influence the effectiveness of ASA or clopidogrel-mediated platelet function inhibition. Nevertheless, women had a significantly increased maximal platelet reactivity compared to men despite antiplatelet therapy.
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Blood Coagul. Fibrinolysis · Dec 2012
Coagulation factors and antithrombin levels in young and elderly subjects in Pakistani population.
Aging is associated with increased levels of coagulation factors and decrease in natural anticoagulant factors. This strongly supports that age-related hypercoagulable state occurs in elderly. This study aimed to measure the plasma levels of coagulation factors and anticoagulant levels in young and elderly to observe the effect of age on haemostatic system. ⋯ Factor VIII rose with age in both sexes (P = 0.001). Higher antithrombin activity was observed in the younger group whereas the older group demonstrated significantly lower antithrombin activity (P = 0.001). We conclude that considerable effects of age and sex are observed on coagulation factors and naturally occurring inhibitors.
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Blood Coagul. Fibrinolysis · Dec 2012
Case ReportsDrug-induced thrombocytopenia: a less known interaction.
A 57-year-old woman with a left frontal lobe tumor was started on seizure prophylaxis with phenytoin and dexamethasone while awaiting elective surgery for tumor excision. Within a week, she developed a rash all over her body secondary to phenytoin hypersensitivity and her platelet counts decreased progressively to as low as 20,000/μl. ⋯ This case of phenytoin-induced thrombocytopenia emphasizes the importance of recognizing thrombocytopenia secondary to drug use and also highlights a lesser known but important interaction between phenytoin and dexamethasone to enhance this effect. We also provide a brief review of the literature and comment on the pathophysiology of this rare condition.