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Factor VIII Activity (factor + viii_activity)

Distribution by Scientific Domains

Medical Sciences	100%

Selected Abstracts

Increased Levels of Tissue Plasminogen Activator Antigen and Factor VIII Activity in Nonvalvular Atrial Fibrillation: Relation to Predictors of Thromboembolism

JOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 8 2001
TZUNG-DAU WANG M.D.
Atrial Fibrillation and Hypercoagulability.Introduction: Given that nonvalvular atrial fibrillation (AF)-associated stroke can be either cardioembolic or atherothrombotic, we investigated the relationships between nonvalvular AF and hemostatic factors reflecting intrinsic thrombogenic and atherogenic potentials (tissue plasminogen activator [t-PA] antigen, plasminogen activator inhibitor-1, and factor VIII activity). We also evaluated the clinical applicability of these hemostatic factors by examining whether AF subjects with established clinical or echocardiographic predictors of thromboembolism had higher levels of these factors. Methods and Results: Of the 3,212 participants of a Chinese population-based study, 53 subjects (1.7%) with AF were identified. Among the hemostatic factors measured, t-PA antigen (median 12.8 vs 8.1 ng/mL; P < 0.01) and factor VIII activity (median 155% vs 133%; P < 0.05) were significantly higher in AF subjects after adjustment for age and sex. In multivariate analysis, features independently associated with t-PA antigen levels were AF, age, sex, body mass index, systolic blood pressure, total cholesterol, triglycerides, and left ventricular systolic dysfunction. Features independently associated with factor VIII activity levels included AF, age, and total cholesterol. Levels of both t-PA antigen and factor VIII activity were primarily elevated in AF subjects with predictors of thromboembolism (age > 75 years, hypertension, diabetes, and left ventricular systolic dysfunction), whereas in AF subjects with no thromboembolic predictors, plasma levels of hemostatic factors examined were similar to those without AF. Conclusion: We demonstrated that nonvalvular AF was independently associated with increased peripheral levels of t-PA antigen and factor VIII activity. Levels of both hemostatic factors were primarily elevated in AF subjects with predictors of thromboembolism. Whether these hemostatic factors are independently predictive of future thromboembolic events in AF patients requires further investigation. [source]

Procoagulant factors and the risk of myocardial infarction in young women

EUROPEAN JOURNAL OF HAEMATOLOGY, Issue 1 2006
Bea Tanis
Abstract:,Objectives:,We investigated whether elevated levels of factor VIII, IX and XI is associated with myocardial infarction (MI) in young women. In addition, we studied ABO blood group, von Willebrand factor (VWF) and C-reactive protein (CRP). Methods and results:,We compared 200 women with MI before age 49 years with 626 controls from a population-based case,control study. Mean levels of factor VIII activity (VIII), von Willebrand factor antigen (VWF), factor IX activity (IX) were higher in patients (133, 134 and 132 IU/dL) than in controls (111, 107 and 120 IU/dL, respectively). Mean levels of factor XI (XI) were equal in patients (114 IU/dL) and controls (113 IU/dL). The odds ratio (OR) for MI for blood group non-O vs. O was 1.6 [95% confidence interval (CI) 1.1,2.3]. The OR adjusted for age, index year and area of residence for the highest quartile >150 IU/dL of factor VIII was 2.7 (95% CI 1.6,4.6), of VWF 4.7 (95% CI 2.3,9.7), of factor IX 2.6 (95% CI 1.3,5.4) and of factor XI 0.9 (95% CI 0.5,1.4), all compared with the lowest quartile <100 IU/dL. Conclusions:,Non-O blood group, high VWF, factor VIII and factor IX levels are associated with an increased risk of MI in young women, while high factor XI levels are not. [source]

ORIGINAL ARTICLE Laboratory science: Spectrum of F8 gene mutations in haemophilia A patients from a region of Italy: identification of 23 new mutations

HAEMOPHILIA, Issue 5 2010
F. RICCARDI
Summary., Haemophilia A (HA) is an X-linked recessive bleeding disorder caused by a lack or decrease of coagulation factor VIII activity. The molecular diagnosis of HA is challenging and a variety of different mutations have been identified throughout the F8 gene. Our aim was to detect the causative mutation in 266 HA patients from Emilia-Romagna region (Italy) and in all suspected carriers. Molecular analysis of F8 in 201 HA patients (152 index cases) was performed with a combination of several indirect and direct molecular approaches, such as long distance polymerase chain reaction, multiplex ligation-dependent probe amplification, denaturing high performance liquid chromatography and direct sequencing. The analysis revealed 78 different mutations, 23 of which were novel, not having been reported in national or international databases. The detection rate was 100%, 86% and 89% in patients with severe, moderate and mild HA, respectively. The information provided by this registry will be helpful for monitoring the treatment of HA patients in Emilia-Romagna and also for reliable genetic counselling of affected families in the future. [source]

Mild haemophilia: a disease with many faces and many unexpected pitfalls

HAEMOPHILIA, Issue 2010
K. PEERLINCK
Summary., Despite major advances in diagnosis and treatment, the management of patients with mild haemophilia (MH) remains a major challenge. Mild haemophilia is defined by factor levels between 0.05 and 0.40 IU mL,1. The bleeding associated with mild haemophilia is most frequently episodic, occurring during surgery or following trauma. Spontaneous bleeding is rare. Diagnosis is sometimes delayed because of insensitivity of screening clotting assays or discrepancies in factor VIII activity as measured by different assays. The treatment of choice in mild haemophilia A is desmopressin, which typically induces a 2,6-fold increase of factor VIII over baseline. However, desmopressin has its limitations in this setting such as the occurrence of tachyphylaxis and failure to respond in an undetermined proportion of patients. Factors underlying poor biological response or magnitude of response to desmopressin are incompletely understood. Inhibitor development in mild haemophilia is particularly distressing. This complication arises at an older age in this patient group because of infrequent need for factor VIII replacement. Inhibitors in mild haemophilia patients often cross-react with endogenous factor VIII resulting in severe spontaneous bleeding frequently in a postoperative setting. Intensive perioperative use of factor VIII and some specific mutations induce a particularly high risk for inhibitor development, but risk factors are incompletely understood. For reasons of the older age of the patients, treatment of bleeding with bypassing agents may cause major thrombotic complications. Data on therapeutic options for inhibitor eradication in patients with mild haemophilia are particularly scarce. With increased life-expectancy for all haemophilia patients, the group of elderly patients with mild haemophilia requiring major surgery will further increase. Prevention of inhibitors, particularly in this patient group, should be a major topic of interest in both clinic and research. [source]

Hypothyroidism and acquired von Willebrand's syndrome: a systematic review

HAEMOPHILIA, Issue 3 2008
E. MANFREDI
Summary., Acquired von Willebrand's syndrome type I is the supposed main underlying cause of bleeding tendency in hypothyroid patients. The purpose of this systematic review was to summarize the published evidence on the association between hypothyroidism and acquired von Willebrand's syndrome. All published clinical epidemiological and interventional studies, case reports and in vitro studies that investigated the association between hypothyroidism and acquired von Willebrand's syndrome were identified by a computer-assisted search of the MEDLINE and EMBASE electronic databases. A quality assessment was performed for clinical epidemiological studies. A total of 41 papers were included. A total of 22 epidemiological in vivo studies, two in vitro studies and 47 case reports were finally analyzed. No high quality in vivo study was identified. Almost all bleeding episodes described in the case reports were mucocutaneous. von Willebrand factor (VWF) antigen value was available for 23 patients: median value 28 U/dL (range: 4,45); VWF activity was available for 24 patients: median value 28.5 U/dL (range: <3,55); factor VIII activity was available for 16 patients: median value 47 U/dL (range: 9,74). Acquired von Willebrand's syndrome may be the main factor responsible for bleeding diathesis in overt hypothyroid patients. Even if bleeding episodes are mainly mild and mucocutaneous, blood transfusion, drug administration or surgical procedure may be required. [source]

Discrepant factor VIII activity in a family with mild haemophilia A and Arg531His mutation using various FVIII assays and APTT reagents

HAEMOPHILIA, Issue 5 2005
J. F. Lucía
First page of article [source]

Increased Levels of Tissue Plasminogen Activator Antigen and Factor VIII Activity in Nonvalvular Atrial Fibrillation: Relation to Predictors of Thromboembolism

Inherited defects of coagulation factor V: the hemorrhagic side

JOURNAL OF THROMBOSIS AND HAEMOSTASIS, Issue 1 2006
R. ASSELTA
Summary., Coagulation factor V (FV) is the protein cofactor required in vivo for the rapid generation of thrombin catalyzed by the prothrombinase complex. It also represents a central regulator in the early phases of blood clot formation, as it contributes to the anticoagulant pathway by participating in the downregulation of factor VIII activity. Conversion of precursor FV to either a procoagulant or anticoagulant cofactor depends on the local concentration of procoagulant and anticoagulant enzymes, so that FV may be regarded as a daring tight-rope walker gently balancing opposite forces. Given this dual role, genetic defects in the FV gene may result in opposite phenotypes (hemorrhagic or thrombotic). Besides a concise description on the structural, procoagulant and anticoagulant properties of FV, this review will focus on bleeding disorders associated with altered levels of this molecule. Particular attention will be paid to the mutational spectrum of type I FV deficiency, which is characterized by a remarkable genetic heterogeneity and by an uneven distribution of mutations throughout the FV gene. [source]

Preclinical experiment of auxiliary partial orthotopic liver transplantation as a curative treatment for hemophilia

LIVER TRANSPLANTATION, Issue 5 2005
Saiho Ko
The cause of hemophilia is deficiency of coagulation factor VIII production in the liver, which can be cured by liver transplantation. Because the hepatic function of hemophilia patients is quite normal except for production of factor VIII, auxiliary partial orthotopic liver transplantation (APOLT) is beneficial in that patient survival is secured by preserving native liver even in the event of graft loss. However, it is not known whether the graft of APOLT would be enough to cure hemophilia. We evaluated the efficacy and feasibility of APOLT for hemophilia in a canine hemophilia A model that we established. Partial left liver graft was taken from the normal donor (blood factor VIII activity > 60%). The graft was transplanted to the hemophilia beagle dog (blood factor VIII activity < 5%) after resection of the left lobe preserving native right lobe. Changes in time of blood factor VIII activity and liver function parameters were observed after APOLT. APOLT and perioperative hemostatic management were successfully performed. The blood factor VIII activity increased to 30% after APOLT, and was sustained at least 6 weeks throughout the observation period without symptoms of bleeding. The result demonstrated sustained production of factor VIII in the hemophilia recipient after APOLT. Transplantation of approximately one third of whole liver resulted in cure of hemophilia. In conclusion, it is suggested that APOLT would be feasible as a curative treatment of hemophilia A to improve quality of life of the patients. (Liver Transpl 2005;11:579,584.) [source]