Orthostatic stress causes significant plasma shift and raises transmural pressure in lower extremities, resulting in an increase in endothelial activation and plasma proteins concentrations, possibly including coagulation factors. This may lead to activation of the coagulation system during standing. To test this hypothesis, we recruited 18 healthy volunteers (9 females and 9 males; mean age: 2...

Hemophilia B is an X-linked recessive bleeding disorder resulting from a deficiency of the coagulation factor IX (FIX) protein activity, a vitamin K-dependent serine protease active in both the intrinsic and extrinsic coagulation systems. DNA analyses of the factor IX gene in two unrelated patients with severe hemophilia B, with a IX coagulant activity less than 1% and undetectable FIX antigen,...

Gene therapy is an attractive approach for the treatment of hemophilia, as continuous expression of donated clotting factor VIII (FVIII) DNA would ensure clotting factor replacement at constant circulating levels rather than at the peaks and troughs that characterize the current protein infusion therapeutic approach. In this issue of the JCI, Shi et al. describe an interesting variant of a gene...

The cellular source of coagulation factor VIII (FVIII) remains controversial. Like many coagulation proteins, FVIII is produced in the liver, and FVIII synthesis has long been associated with hepatocytes. But extrahepatic synthesis also occurs, and mounting evidence suggests that hepatocytes are not responsible for FVIII production. To determine the tissue that synthesizes FVIII, we developed a...

Factors V, VII, VIII, X, XI, and XII of the coagulation system, platelet count, and antithrombin III levels were assayed in 20 healthy volunteers aged 20-40 years and 61 elderly subjects aged 66-96 years whose skinfold thickness was also measured. Factors XI, XII, and antithrombin III levels tended to increase in women and decrease in men while factors X, VII, and V tended to increase in both m...

BACKGROUND & AIMS Wilson disease (WD) is an autosomal recessive disorder of copper metabolism. Alterations of copper metabolism have been associated with changes in coagulation factors. The aim of the present study was the analysis of coagulation factors in WD patients. METHODS 100 patients attending a tertiary WD outpatient clinic were analyzed in a prospective cross sectional cohort study. ...

Factor VIII functions as a cofactor in the intrinsic coagulation pathway and must first be activated to function optimally in this capacity. Low concentrations of thrombin activate factor VIII, and the presence of stimulated platelets is known to enhance the activation of factor VIII complexed to von Willebrand factor. The current studies show that platelets stimulated by thrombin, collagen, or...

Tests of coagulation, fibrinolysis, and platelet function were performed in 17 patients with intact molar pregnancies. Women with intact molar pregnancies had higher fibrinogen factor VIII, and fibrinogen degradation products, concentrations and lower prothrombin, factor X, plasminogen, and plasminogen activator concentrations than controls with normal pregnancies. They also had reduced platele...

Pregnancy induces complex changes concerned with hemostasis. Normal pregnancy is associated with hypercoagulable state which becomes more pronounced at term while in pre-eclampsia or pregnancyinduced hypertension (PIH), localized coagulation fibrinolytic imbalance has been reported(l,2). Various coagulation factors are decreased in concentration in PIH, especially fibrinogen, factor V, VII, VII...

A Study of Blood Coagulation Following an Acute Stroke • A battery of blood coagulation tests were performed on 14 acute stroke patients. Various abnormalities were found, notably elevation of blood fibrinogen, factor VIII, prothrombin, platelet factor 3, and a shortened P.T.T. The significance of these findings is discussed and they are considered to be of no importance since similar changes w...