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Hemostatic Defects (hemostatic + defect)
Selected AbstractsHemostatic Defect in Baboons Autotransfused Treated Plasma to Simulate Shed BloodJOURNAL OF CARDIAC SURGERY, Issue 6 2006C. Robert Valeri M.D. This study was done to determine how autotransfusion of nontreated plasma and plasma treated with urokinase with and without aprotinin affected hemostasis in healthy baboons. Methods: A 500-mL volume of blood was collected from the baboon, a 250-mL volume of plasma was isolated, and the RBCs were reinfused. Three baboons were autotransfused untreated plasma. Four baboons received plasma that had been treated with 3000 IU/mL urokinase at +37°C for 30 minutes. Eight baboons received plasma that had been treated first with urokinase 3000 IU/mL at +37°C for 30 minutes and then with aprotinin (1000 KIU/mL). Bleeding time, fibrinogen degradation products (FDP), D-dimer, and alpha-2 antiplasmin levels were measured. Results: During the 4-hour period following autotransfusion of the urokinase-aprotinin-treated plasma, the levels of D-dimer and FDP were significantly higher and fibrinogen and alpha-2 antiplasmin levels were significantly lower than those levels seen after the autotransfusion of nontreated plasma. FDP and D-dimer levels showed significant positive correlations with prothrombin time (PT) and activated partial thromboplastin time (aPTT). A significant negative correlation was observed between thrombin time (TT) and fibrinogen level. A significant positive correlation was observed between bleeding time and D-dimer level and a significant negative correlation between the bleeding time and the fibrinogen level. Conclusions: The infusion of a volume of urokinase or urokinase-aprotinin treated autologous plasma equivalent to 15% of the blood volume was not associated with a bleeding diathesis in healthy baboons. [source] Expression studies on a novel type 2B variant of the von Willebrand factor gene (R1308L) characterized by defective collagen bindingJOURNAL OF THROMBOSIS AND HAEMOSTASIS, Issue 12 2005L. BARONCIANI Summary., A novel mutation, R1308L (3923G > T) was present in the heterozygous state in five members of a family with type 2B von Willebrand disease (VWD) characterized by a full set of von Willebrand factor (VWF) multimers in plasma and by the absence of thrombocytopenia before and after desmopressin (DDAVP). The defect (R1308L) was located at the same amino acid position of one of the most common mutations associated with type 2B VWD (R1308C), which is characterized by the loss of high molecular weight VWF multimers (HMWM) in plasma and the occurrence of thrombocytopenia. To understand the mechanisms of this defect, the novel (R1308L) and ,common' (R1308C) mutations were expressed in COS-7 cells, either alone or, to mimic the patients' heterozygous state, together with wild-type VWF. R1308L recombinant VWF (rVWF) had a higher affinity for the platelet glycoprotein Ib, (GPIb,) receptor than wild-type rVWF, R1308C rVWF showing an even higher affinity. A novel finding was that both mutant rVWFs showed a similarly reduced binding to collagen type I and type III in comparison with wild-type rVWF. The latter finding suggests a more important role than recognized so far for the VWF A1 domain in VWF binding to collagen, which may contribute to the in vivo hemostatic defect associated with type 2B VWD. [source] Evaluation of low PAI-1 activity as a risk factor for hemorrhagic diathesisJOURNAL OF THROMBOSIS AND HAEMOSTASIS, Issue 1 2006A. ÅGREN Summary.,Background: Prospective studies of the epidemiology and clinical significance of low plasminogen activator inhibitor type 1 (PAI-1) activity are lacking. Objective: To evaluate the prevalence of low PAI-1 activity in patients with a bleeding tendency in comparison with a normal population. Methods: In 586 consecutive patients, referred because of bleeding symptoms, we added analyses of PAI-1 activity and tissue plasminogen activator complex with PAI-1 (t-PA,PAI-1) to the routine investigation, consisting of platelet count, bleeding time, prothrombin time, activated partial thromboplastin time, fibrinogen, factor VIII, von Willebrand factor activity, and antigen. Controls were 100 blood donors and 100 age- and sex-matched healthy individuals. The latter were also evaluated regarding the previous bleeding episodes. The bleeding history was classified as clinically significant or not, and the criteria were fulfilled in 75% of the patients and 18% of the healthy controls. Results: The routine laboratory investigation of the patients was negative in 57%. Low PAI-1 activity, defined as <1.0 U mL,1, was found in 23% of the patients and in 13% and 10% of the blood donors and healthy controls, respectively (odds ratio and 95% CI, 2.04; 1.11,3.77 and 2.75; 1.39,5.42, respectively). The difference remained statistically significant after the adjustment for body mass index, use of estrogens, sex and age (odds ratio for patients vs. healthy controls 3.23; 95% CI, 1.22,8.56, P = 0.019). The distribution of the 4G/5G genotypes in the patients was not different from that of two control populations. No specific symptom predicted for low PAI-1, which did not aggravate the clinical picture in association with the other hemostatic defects. Low tPA,PAI-1 was not associated with the increased bleeding tendency. Conclusion: Low PAI-1 activity is common in patients with a bleeding diathesis, but it is a risk factor of minor clinical importance and not associated with specific bleeding manifestations. [source] Hemostatic and hematological abnormalities in gain-of-function fps/fes transgenic mice are associated with the angiogenic phenotypeJOURNAL OF THROMBOSIS AND HAEMOSTASIS, Issue 11 2004W. Sangrar Summary. The Fps/Fes tyrosine kinase has been implicated in the regulation of hematopoiesis and inflammation. Mice expressing an activated variant of Fps/Fes (MFps) encoded by a gain-of-function mutant transgenic fps/fes allele (fpsMF) exhibited hematological phenotypes, which suggested that Fps/Fes can direct hematopoietic lineage output. These mice also displayed marked hypervascularity and multifocal-hemangiomas which implicated this kinase in the regulation of angiogenesis. Here we explored the potential involvement of Fps/Fes in the regulation of hemostasis through effects on blood cells and the vascular endothelium. Hematological parameters of fpsMF mice were characterized by peripheral blood analysis, histology, and transmission electron microscopy. Hemostasis parameters and platelet functions were assessed by flow cytometry and measurements of activated partial thromboplastin time, prothrombin time, thrombin clot time, platelet aggregation, bleeding times and in vitro fibrinolytic assays. Hematological and morphological analyses showed that fpsMF mice displayed mild thrombocytopenia, anemia, red cell abnormalities and numerous hemostatic defects, including hypofibrinogenemia, hyper-fibrinolysis, impaired whole blood aggregation and a mild bleeding diathesis. fpsMF mice displayed a complex array of hemostatic perturbations which are reminiscent of hemostatic disorders such as disseminated intravascular coagulation (DIC) and of hemangioma-associated pathologies such as Kasabach,Merritt phenomenon (KMS). These studies suggest that Fps/Fes influences both angiogenic and hemostatic function through regulatory effects on the endothelium. [source] Two novel fibrinogen variants found in patients with pulmonary embolism and their familiesJOURNAL OF THROMBOSIS AND HAEMOSTASIS, Issue 6 2003M. M. L. Hanss Summary.,Background:,The occurrence of dysfibrinogen is quite rare in comparison with other hemostatic defects, specially in cases of venous thrombosis. Objectives:,Fibrinogen is known to have multiple functions, which are not evaluated by simple coagulation testing. We have used gel electrophoresis to search for new mutations. Patients and methods:,Specimens of purified fibrinogen from 217 consecutive patients with familial or recurrent or early thrombosis and from 490 control subjects were evaluated by electrophoresis. Plasma fibrinogen levels and coagulation-dependent tests (electromechanical and optical coagulometric determinations, immunological measurement, thrombin and Reptilase® times) were normal. Results:,Two novel familial variants were detected. For a 42-year-old patient, an in-frame 117 base pair insertion in the A,-chain gene caused a 5-kDa mobility shift of the A, chain. This corresponds to a 39 amino acid duplication in the connector domain (fibrinogen Champagne au Mont d'Or). This pattern was also found in the patient's mother and child. A second 31-year-old patient presented an extra band under non-reducing conditions, 30 kDa larger than HMW fibrinogen and reacting with antifibrinogen antibodies (fibrinogen Lozanne). A heterozygous 5909A,G mutation was found on the B,-chain gene leading to heterozygous B, Tyr236, stop codon. The predicted truncated B, chain could participate in chain assembly. Two family members were also affected, one of whom had suffered early venous thrombosis. Conclusions:,Electrophoretic testing of apparently normal fibrinogens can reveal new variants which may be clinically relevant. [source] The use of desmopressin as a hemostatic agent: A concise reviewAMERICAN JOURNAL OF HEMATOLOGY, Issue 8 2007Massimo Franchini Desmopressin, a synthetic derivative of the antidiuretic hormone vasopressin, is the treatment of choice for most patients with von Willebrand disease and mild hemophilia A. Moreover, the compound has been shown to be useful in a variety of inherited and acquired hemorrhagic conditions, including some congenital platelet function defects, chronic liver disease, uremia, and hemostatic defects induced by the therapeutic use of antithrombotic drugs such as aspirin and ticlopidine. Finally, desmopressin has been used as a blood saving agent in patients undergoing operations characterized by large blood loss and transfusion requirements, but studies suggest that this is not as effective as other methods. This review briefly summarizes the current clinical indications on the use of desmopressin as a hemostatic agent. Am. J. Hematol., 2007. © 2007 Wiley-Liss, Inc. [source] | ||||||||||