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At least 19 recordsLinked to original sources
PubMed1978

Role of surface in surface-dependent activation of Hageman factor (blood coagulation factor XII).

The mechanism by which negatively charged substances such as celite, kaolin, or ellagic acid contribute to the surface-dependent activation of Hageman factor (Factor XII) was studied. Kinetic studies of the proteolytic activation of (125)I-labeled human Hageman factor by human plasma kallikrein, plasma, activated Factor XI, and trypsin were performed in the presence and absence of high molecular weight kininogen and surface materials such as celite, kaolin, or ellagic acid. The results showed that surface-bound Hageman factor was 500 times more susceptible than soluble Hageman factor to proteolytic activation by kallikrein in the presence of high molecular weight kininogen. Surface binding of Hageman factor enhanced its cleavage by plasmin, activated Factor XI, and trypsin by 100-fold, 30-fold, and 5-fold, respectively. On a molar basis, trypsin was twice as potent as kallikrein in the cleavage of the surface-bound Hageman factor, while plasmin and activated Factor XI were an order of magnitude less potent than kallikrein. Kallikrein even at concentrations as low as 0.5 nM (i.e., 1/1000th of the concentration of prekallikrein in plasma) was very potent in the limited proteolysis of the surface-bound Hageman factor. These results suggest that substances classically known as "activating surfaces" promote the activation of Hageman factor indirectly by altering its structure such that it is much more susceptible to proteolytic activation by other plasma or cellular proteases.

Adsorption↗
PubMedDate not supplied

Test method for the absence of active clotting factors in dried human blood coagulation factor IX complex.

Adverse effects possibly due to the active clotting factors are sometimes reported upon administration of some preparations of Factor IX complex having conformed to the specifications in the Japanese Minimum Requirements for Biological Products. The author, therefore, proposed the revision of the test method for the absence of active clotting factors in the Minimum Requirements by introducing calcium ion into the test medium.

Calcium↗
PubMed1977

Labeling of a major fibroblast surface protein (fibronectin) catalyzed by blood coagulation factor XIIa.

Incubation of cultured human fibroblasts with blood coagulation factor XIIIa (plasma transglutaminase, fibrinoligase) and the fluorescent primary amine, N-(5-aminopentyl)-5-dimethylaminonaphthalene-1-sulfonamide, resulted in fluorescent labeling of three cellular polypeptides. The molecular weights of the labeled polypeptides, estimated by polyacrylamide gel electrophoresis in sodium dodecyl sulfate after reduction, were: greater than 1.2-10(6), 2.2-10(5), and 1.3-10(5). The labeled 2.2-10(5) dalton polypeptide was susceptible to mild trypsinization and not present in cultures of SV-40 transformed fibroblasts, indicating that it is the subunit of cell-surface fibronectin and identical with the external transformation-sensitive polypeptide of similar molecular weight described by others. Upon coelectrophoresis, the labeled 2.2-10(5) dalton polypeptide migrated slightly behind the subunit of plasma fibronectin (cold-insoluble globulin), indicating that the immunologically cross-reactive forms of fibronectin in human plasma and cultured human fibroblasts differ slightly in molecular weight. The identities of the labeled greater than 1.2-10(6) and 1.3-10(5) dalton polypeptides are not known. The XIIa-reactive glutamine residues of fibroblast cell-surface proteins are potential sites for intermolecular cross-linking (by xi-(gamma-glutamyl)lysyl linkages) to other proteins of connective tissue.

Binding Sites↗
PubMed1976

Progestational agents and blood coagulation. VII. Thromboembolic and other complications of oral contraceptive therapy in relationship to pretreatment levels of blood coagulation factors: summary report of a ten-year study.

During a ten-year period, 348 women were studied for a total of 5,877 patient months in four separate studies relating oral contraceptives to changes in hematologic parameters. Significant increases in certain factors of the blood coagulation and fibrinolysin systems (factors I,II,VII,VIII,IX, and X and plasminogen) were observed in the treated groups. Severe complications developed in four patients. All four had an abnormal blood coagulation profile, suggesting "hypercoagulability" before initiation of therapy. Some of these findings represented the most extreme abnormalities seen in the entire group of patients; some increased further during therapy. One of these patients developed a myocardial infarction before receiving any medication, shortly after the base-line values were obtained. One patient developed retinopathy 19 months after she began therapy, and another developed thrombophlebitis after 27 months of therapy. The fourth patient developed thrombophlebitis 14 days after initiation of contraceptive therapy. All four patients were of the A or AB blood group. Previous studies suggested the possiblility of increased propensity for thromboembolic episodes in patients possessing the A antigen. It appears from these data that hematologic work-ups may be useful in women who are about to start long-term oral contraceptive therapy.

Adult↗
PubMedDate not supplied

[Blood coagulation factors of the vascular wall and myocardium in hypokinesia in rabbits].

The effect of hypokinesia on the hemocoagulatory and fibrinolytic properties of aorta, myocardium and venae cavae was studied. Hypokinesia decreased thromboplastic activity of the intima and increased that of the mid- and outer layers of the aorta. Anticoagulatory properties of aortal and myocardial tissues increased whereas their antithrombin properties decreased. Rabbit immobilization increased the content of fibrinolytic stimulants in the aorta and myocardium.

Animals↗
PubMed1977

Progestational agents and blood coagulation. VIII. Effect of low-dose, alternate-day, estrogen-progestin combinations on blood coagulation factors in man, with a special note on the effect of freezing of blood samples.

Changes in the blood coagulation system were studied in three groups of 20 patients each. The first group received 0.5 mg. of norethindrone daily, plus 0.06 mg. of ethinyl estradiol on alternate days from cycle Day 5 through 25. The second group, all of whom had been fitted with an intrauterine contraceptive device (IUD), received no hormonal treatment and served as a control group. The third group received 0.5 mg. of norethindrone daily, combined with 0.045 mg. of ethinyl estradiol given on alternate days from cycle Day 5 through 25. Blood samples were drawn prior to the initiation of the study and after three months of treatment. Tests of the following parameters of the blood coagulation system were performed: direct platelet count; platelet adhesiveness; prothrombin time; thrombin time; fibrinogen; factor II assay; activity of factors V, VII, VIII, IX, and X; antithrombin III; and fibrin/fibrinogen degradation products. For a number of these factors, both fresh and frozen blood samples were examined. It was concluded that the two treatment regimens, with the use of alternate-day estrogen administration over a three-month period, had no clinically significant effect on the blood coagulation system.

Adolescent↗
PubMed1976

Contributions to the optimal use of human blood. VIII. Stability of blood coagulation factor VII during collection and storage of whole blood and plasma.

Investigations were performed concerning the influence of the pH on the stability of factor VIII during the collection of blood and during the storage of blood and plasma for varying periods and at varying temperatures. It was found that the low pH of ACD anticoagulant solution (pH 4.9) caused a loss of factor VIII procoagulant activity of 10-15% during the collection of blood. However, when less acidic anticoagulant solutions were used, substantial losses of factor VIII occurred during the storage of blood. We concluded that the optimal pH of both the anticoagulant solution and the stored blood, should be between 6.7 and 7.0. However, no anticoagulant solution is known that meets these requirements. In practice ACD ensures the highest recovery of factor VIII in cryoprecipitate, at least in those cases where the blood donations are stored for several hours before separation and freezing of the plasma.

Anticoagulants↗
PubMed1977

[Precision control of a single step determination of blood coagulation factor VIII in the plasma].

The findings of a precision control are reported for a one-stage determination of the factor VIII activity in the plasma for a period of 6 months. The storage property of the reagents was achieved by storing them in fluid nitrogen. Coefficients of variation under 55 were achieved at controlling the normal range as well as the pathological one. Thus the precision of this method may be compared with that of clinicochemical examinations.

Blood Coagulation Tests↗