Clotting factors

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Clotting factors

Substances in the blood that act in sequence to stop bleeding by forming a clot.


the formation of a jellylike substance over the ends or within the walls of a blood vessel, with resultant stoppage of the blood flow. Clotting is one of the natural defense mechanisms of the body when injury occurs. A clot will usually form within 5 minutes after a blood vessel wall has been damaged. The clotting mechanism is triggered by the platelets, which disintegrate as they pass over rough places in the injured surface. As they disintegrate they release serotonin and thromboplastin. Serotonin causes constriction of the blood vessels and reduction of local blood pressure. Thromboplastin unites with calcium ions and other substances which promote the formation of fibrin. When examined under a microscope, a clot consists of a mesh of fine threads of fibrin in which are embedded erythrocytes and leukocytes, small amounts of fluid (serum), and platelets.

clotting defects
clotting factors
a series of plasma proteins which are related through a complex cascade of enzyme-catalyzed reactions involving the sequential cleavage of large protein molecules to produce peptides, each of which converts an inactive zymogen precursor (factor II) into an active enzyme (Iia) leading to the formation of a fibrin clot. They are designated by Roman numerals, and an additional 'a' to indicate the activated state. They are: factor I (fibrinogen), factor II (prothrombin), factor III (tissue thromboplastin), factor IV (calcium), factor V (proaccelerin), factor VI (no longer considered active in hemostasis), factor VII (proconvertin), factor VIII (antihemophilic factor), factor IX (plasma thromboplastin component; Christmas factor), factor X (stuart factor), factor XI (plasma thromboplastin antecedent), factor XII (hageman factor), factor XIII (fibrin stabilizing factor).
clotting time
the time required for blood to clot in a glass tube; a measure of the intrinsic system of coagulation. In the Lee-White method, blood in test tubes is maintained at a constant temperature and examined regularly until clotting occurs; the test can be also be performed in capillary tubes. Called also coagulation time. Less sensitive and now less often used than the activated coagulation time.
tissue clotting factor
clotting factor III; tissue thromboplastin.
References in periodicals archive ?
The lack of a clotting factor in hemophilia is caused by a defect in the gene that carries the instruction on how the clotting factor should be made.
Additionally, the presence of specific inhibitors, commonly targeting factor VIII, can cause clotting factor degradation.
15) If the thawed FFP is immediately transfused, it remains rich in clotting factors.
Given the considerable time it takes to prepare clotting factors for infusion, and the rapid nature of massive obstetric hemorrhage, the obstetrician may have only minutes to make life-saving decisions about management.
This strongly suggests that the reduced use of clotting factors was associated with the addition of ribavirin," the investigators wrote.
Researchers found that genetic factors accounted for a significant variation in the levels of these clotting factors.
The incidence of von Willebrand disease - which is similar to hemophilia but different in that the deficient clotting factor does not always remain at the same level - is not known.
That's just one clue as to what's happening in the body, where a slew of clotting factors interact.
Of the 25,000 hemophiliacs in the United States, nearly 90 percent suffer from forms that are treatable with two costly biological drugs known as blood clotting factors 8 and 9.
Contract notice: "Delivery of clotting factors and drugs included in the list of nhif reimbursement.
In haemophilia, an inherited deficiency of blood clotting factors because of abnormal genes, even a small cut may bleed for hours or days and there may be episodes of spontaneous bleeding.