blood coagulation


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coagulation

 [ko-ag″u-la´shun]
1. in surgery, the disruption of tissue by physical means to form an amorphous residuum, as in electrocoagulation or hotocoagulation.
2. in colloid chemistry, solidification of a sol into a gelatinous mass.
blood coagulation clotting.
diffuse intravascular coagulation (disseminated intravascular coagulation (DIC)) see disseminated intravascular coagulation.
coagulation factors factors essential to normal blood clotting, whose absence, diminution, or excess may lead to abnormality of the clotting. Twelve factors, commonly designated by Roman numerals, have been described (I–V and VII–XIII; VI is no longer considered to have a clotting function). (See table 6.)

Factor I is a high-molecular-weight plasma protein that is converted to fibrin through the action of thrombin; deficiency conditions are called afibrinogenemia and hypofibrinogenemia. Called also fibrinogen. Factor II is a glycoprotein present in the plasma that is converted into thrombin in the common pathway of coagulation; deficiency is called hypoprothrombinemia. Called also prothrombin. Factor III is involved in the extrinsic pathway of coagulation, activating factor X; called also tissue thromboplastin or factor.

Factor IV is calcium, required in many stages of blood clotting. Factor V is a heat- and storage-labile material, present in plasma and not in serum and is involved in the intrinsic and extrinsic pathways of coagulation, causing the cleavage of prothrombin to the active thrombin. Deficiency causes parahemophilia. Called also accelerator globulin or factor and proaccelerin. Factor VI is no longer considered in the scheme of hemostasis, and hence is assigned neither a name nor a function.

Factor VII is a heat- and storage-stable material, present in serum and in plasma and participating in the extrinsic pathway of coagulation, acting with factor III to activate factor X. Deficiency, either hereditary or acquired (vitamin k deficiency), leads to hemorrhagic tendency. Called also proconvertin and serum prothrombin conversion accelerator (SPCA). Factor VIII is a relatively storage-labile material that participates in the intrinsic pathway of coagulation, acting as a cofactor in the activation of factor X. Deficiency, an X-linked recessive trait, results in hemophilia a (classical hemophilia). Called also antihemophilic factor (AHF) and antihemophilic globulin (AHG). Factor IX is a relatively storage-stable substance involved in the intrinsic pathway of coagulation, acting to activate factor X. Deficiency of this factor results in a hemorrhagic syndrome called hemophilia b (or Christmas disease), which is similar to classical hemophilia A. It is treated with purified preparations of the factor, derived from human plasma or recombinant, or with factor IX complex. Called also plasma thromboplastin component (PTC) and antihemophilic factor B.

Factor X is a heat-labile material with some storage stability, which is involved in both intrinsic and extrinsic pathways of coagulation, uniting them to begin the common pathway. Once activated, it complexes with calcium, phospholipid, and activated factor V to form prothrombinase, which cleaves and activates prothrombin to thrombin. Called also Stuart or Stuart-Prower factor. Factor XI is a stable factor involved in the intrinsic pathway of coagulation, activating factor IX. Deficiency results in hemophilia c. Called also plasma thromboplastin antecedent (PTA) and antihemophilic factor C. Factor XII is a stable factor activated by contact with glass or other foreign substances, which initiates coagulation through the intrinsic pathway by activating factor XI; called also Hageman factor. Factor XIII is a factor that polymerizes fibrin monomers, enabling fibrin to form a firm blood clot. Deficiency causes a clinical hemorrhagic diathesis. Called also fibrin-stabilizing factor.

blood clot·ting

(blŭd kloting)
Process in which platelets, in conjunction with clotting factors, transform blood from a liquid into a semisolid mass.
Synonym(s): blood coagulation.
References in periodicals archive ?
We therefore conducted this study to investigate the effects of gelatin in a combination with mannitol, which in this study significantly impaired whole blood coagulation and platelet function.
A coagulation factor becomes useful in the study of acute leukemias: Studies with blood coagulation factor XIII.
The combination of the hypersaline environment, hyperosmosis, and hypothermia induced by seawater immersion may contribute to the abnormal changes in the morphology and gene expression of VECs, causing a disorder of blood coagulation and DIC.
These were the activated Partial Thromboplastin Time (aPTT) test which measures the intrinsic pathway of blood coagulation and the Prothrombin Time (PT) test which monitors the tissue factor (extrinsic) pathway of clotting.
The underlying mechanisms linking air pollutants and increased cardiovascular risk remain unclear, although prior studies have associated exposure to air pollution with activation of inflammatory pathways, production of reactive oxygen species, endothelial injury and dysfunction, arterial vasoconstriction, and alterations in blood coagulation factors.
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But soon, thanks to startup Qloudlab, based in the microengineering lab in Switzerland's EPFL tech university, these patients may be able to use the touch screens on their phones or other devices to test their blood coagulation, all in the comfort of their own homes.
There are cases where people who met with an accident or underwent surgery died owing to defective blood coagulation. The research was published in the journal Biomedical Optics Express.
During scarification process, three blood samples were immediately withdrawn from the vena cava of each rat and used for blood coagulation, hematology, and biochemical analyses.
A new electronic system launched in May at Al Wakra Hospital's Blood Coagulation Clinic has helped reduce waiting times to just 10 minutes, thus improving the experience of patients.
Martens was hospitalized at the end of August for blood coagulation problems and released on September 9.
Now, the researchers show that the parasite binds a protein in blood vessel walls called endothelial protein C (EPCR), which is involved with regulating blood coagulation and the inflammatory response.