FACTOID # 20: Statistically, Delaware bears more cost of the US Military than any other state.
 
 Home   Encyclopedia   Statistics   States A-Z   Flags   Maps   FAQ   About 
   
 
WHAT'S NEW
 

SEARCH ALL

FACTS & STATISTICS    Advanced view

Search encyclopedia, statistics and forums:

 

 

(* = Graphable)

 

 


Encyclopedia > Coagulation of human blood
Jump to: navigation, search

The coagulation of blood is a complex process during which blood forms solid clots. It is an important part of hemostasis whereby a damaged blood vessel wall is covered by a fibrin clot to stop hemorrhage and aid repair of the damaged vessel. Disorders in coagulation can lead to increased hemorrhage and/or thrombosis and embolism. Red blood cells (erythrocytes) are present in the blood and help carry oxygen to the rest of the cells in the body Blood is a circulating tissue composed of fluid plasma and cells (red blood cells, white blood cells, platelets). ... Hemostasisis the physiologic process which results in the cessation of bleeding in most animals with a closed circulatory system. ... The arterial system The blood vessels are part of the circulatory system and function to transport blood throughout the body. ... Fibrin is a protein involved in the clotting of blood. ... Hemorrhage (alternate spelling is Haemorrhage) is the medical term referring to the presence of blood in the interstitial tissues. ... Thrombosis is the formation of a clot or thrombus inside a blood vessel, obstructing the flow of blood through the circulatory system. ... In medicine, an embolism occurs when an object (the embolus, plural emboli) migrates from one part of the body (through the circulation) and cause(s) a blockage (occlusion) of a blood vessel in another part of the body. ...


Coagulation is similar in all mammals, but as most is known about the system in humans, this article focuses on human blood coagulation.

Contents


In brief

In a normal person coagulation is initiated within seconds after an injury occurs to the blood vessel endothelium; when platelets form a hemostatic plug at the site of injury. This is called primary hemostasis. Secondary hemostasis then follows when plasma components called clotting factors respond (in a complex cascade) to form fibrin strands which strengthen the platelet plug. Contrary to popular belief, coagulation from a cut on the skin is not initiated by air or drying out, but by platelets adhering to and activated by collagen in the blood vessel lining. The activated platelets then release granules that contain pro-coagulant proteins, furthering clotting. The endothelium is the layer of thin, flat cells that lines the interior surface of blood vessels, forming an interface between circulating blood in the lumen and the rest of the vessel wall. ... A 250 ml bag of newly collected platelets. ... Hemostasisis the physiologic process which results in the cessation of bleeding in most animals with a closed circulatory system. ... Hemostasisis the physiologic process which results in the cessation of bleeding in most animals with a closed circulatory system. ... Blood plasma is the liquid component of blood, in which the blood cells are suspended. ... Fibrin is a protein involved in the clotting of blood. ... A 250 ml bag of newly collected platelets. ... Collagen is the main protein of connective tissue. ... A 250 ml bag of newly collected platelets. ... A representation of the 3D structure of myoglobin, showing coloured alpha helices. ...


The use of adsorbent chemicals, such as zeolite, and other hemostatic agents is also being explored for use in sealing severe injuries quickly. In chemistry, adsorption of a substance is its concentration on a particular surface. ... Zeolite Zeolites (Greek, zein,to boil;lithos,a stone) are minerals that have a porous structure. ...


Primary hemostasis

Primary hemostasis is initiated when platelets adhere, using a specific platelet collagen receptor glycoprotein Ia/IIa, to collagen fibers in the vascular endothelium. This adhesion is mediated by von Willebrand factor (vWF), which forms links between the platelet glycoprotein Ib/IX/X and collagen fibrils. A glycoprotein is a macromolecule composed of a protein and a carbohydrate (a sugar). ... Collagen is the main protein of connective tissue. ... The endothelium is the layer of thin, flat cells that lines the interior surface of blood vessels, forming an interface between circulating blood in the lumen and the rest of the vessel wall. ... Von Willebrand factor (vWF, also called Factor VIII-related antigen) is a blood protein of the coagulation system. ...


The platelets are then activated and release the contents of their granules into the plasma, in turn activating other platelets and white blood cells. The platelets undergo a change in their shape which exposes a phospholipid surface for those coagulation factors that require it. Fibrinogen links adjacent platelets by forming links via the glycoprotein IIb/IIIa. In addition, thrombin activates platelets. A 250 ml bag of newly collected platelets. ...


Secondary hemostasis

The coagulation cascade

The coagulation cascade. Legend: HWMK = High molecular weight kininogen, PK = Prekallikrein, TFPI = Tissue factor pathway inhibitor. Black arrow = conversion/activation of factor. Red arrows = action of inhibitors. Blue arrows = reactions catalysed by activated factor. Grey arrow = various functions of thrombin.
The coagulation cascade. Legend: HWMK = High molecular weight kininogen, PK = Prekallikrein, TFPI = Tissue factor pathway inhibitor. Black arrow = conversion/activation of factor. Red arrows = action of inhibitors. Blue arrows = reactions catalysed by activated factor. Grey arrow = various functions of thrombin.

The coagulation cascade of secondary hemostasis has two pathways, the Contact Activation pathway (formally known as the Intrinsic Pathway) and the Tissue Factor pathway (formally known as the Extrinsic pathway) that lead to fibrin formation. It was previously thought that the coagulation cascade consisted of two pathways of equal importance joined to a common pathway. It is now known that the primary pathway for the initiation of blood coagulation is the Tissue Factor pathway. The pathways are a series of reactions, in which a zymogen of a serine protease and its glycoprotein co-factor are activated to become active components that then catalyze the next reaction in the cascade. Coagulation factors are generally indicated by Roman numerals, with a lowercase a appended to indicate an active form, ultimately resulting in cross-linked fibrin. Coagulation, drawn in OpenOffice. ... In biochemistry, a serine proteases or serine endopeptidases (newer name) are a class of peptidases which are characterised by the presence of a serine residue in the active center of the enzyme. ... A glycoprotein is a macromolecule composed of a protein and a carbohydrate (a sugar). ... The system of Roman numerals is a numeral system originating in ancient Rome, and was adapted from Etruscan numerals. ...


The coagulation factors are serine proteases (enzymes) except FVIII and FV which are glycoproteins. The serine proteases act by cleaving other proteins at specific sites. Factor XIII is a transglutaminase. Protein C is also a serine protease. In biochemistry, a serine proteases or serine endopeptidases (newer name) are a class of peptidases which are characterised by the presence of a serine residue in the active center of the enzyme. ... Neuraminidase ribbon diagram An enzyme (in Greek en = in and zyme = blend) is a protein, or protein complex, that catalyzes a chemical reaction and also controls the 3D orientation of the catalyzed substrates. ... Transglutaminases are a family of enzymes (EC 2. ...


The coagulation cascade can be summarised as follows: -

  1. Tissue Factor pathway: the main role of the tissue factor pathway is to generate a "thrombin burst". Thrombin being the single most important constituent of the coagulation cascade in terms of its feedback activation roles. FVIIa circulates in a higher amount than any other activated coagulation factor and following damage to the blood vessel endothelium Tissue Factor (TF) is released, this then forms a complex with FVIIa (TF-FVIIa) this activates FIX and FX. FVII itself is activated by thrombin, FXIa, plasmin, FXII and FXa. The activation of FXa by TF-FVIIa is almost immediately inhibited by tissue factor pathway inhibitor (TFPI). FXa and its co-factor FVa form the prothombinase complex which activates prothrombin to thrombin. Thrombin then activates other components of the coagulation cascade, including FV and FVII (which activates FXI which in turn activates FIX), and activates and releases FVIII from being bound to vWF. FVIIIa is the co-factor of FXIa and together they form the "tenase" complex which activates FX and so the cycle continues.
  2. Contact Activation pathway: formation of the primary complex on collagen by high molecular weight kininogen (HMWK), prekallikrein and FXII (Hageman factor), prekallikrein is converted to kallikrein and FXII becomes FXIIa. FXIIa converts FXI into FXIa. FXI is also activated by FVIIa. Factor IX is in turn activated by FXIa which with its co-factor FVIIIa form the tenase complex which activates FX to FXa. The minor role that the contact activation pathway has in initiating clot formation can be illustrated by the fact that patients with severe deficiencies of FXII, HMWK and prekallikrein do not have a bleeding disorder.
  3. Thrombin Thrombin has a large array of functions. Its primary role is the conversion of fibrinogen to fibrin, the building block of a haemostatic plug. In addition, it activates Factors VIII and V and their inhibitor protein C (in the presence of thrombomodulin), and it activates Factor XIII, which forms covalent bonds that crosslink the fibrin polymers that form from activated monomers.

Following activation by the contact factor or tissue factor pathways the coagulation cascade is maintained in a prothrombotic state by the continued activation of FVIII and FIX to form the tenase complex, until it is down regulated by the anticoagulant pathways. Thrombin (activated Factor II) is a coagulation protein that has many effects in the coagulation cascade. ... Collagen is the main protein of connective tissue. ... High-molecular weight kininogen (HMWK), also known as the Williams-Fitzgerald-Flaujeac factor or the Fitzgerald factor is a protein from the blood coagulation system as well as the kinin-kallikrein system. ... Fibrin is a protein involved in the clotting of blood. ... Protein C is a major physiological anticoagulant. ... Jump to: navigation, search Covalently bonded hydrogen and carbon in a molecule of methane. ...


Cofactors and inhibitors

Various substances are required for the proper functioning of the coagulation cascade:

  • Calcium and phospholipid (a cell membrane constituent) are required for the tenase and prothrombinase complexes. Calcium mediates the binding of the complexes via the terminal gamma-carboxy residues on FXa and FIXa to the phospholipid surfaces expressed by platelets. Calcium is also required at other points in the coagulation cascade.
  • Vitamin K is an essential factor to a hepatic gamma-glutamyl decarboxylase that adds a second carboxyl group to glutamic acid residues on factors II, VII, IX and X, as well as Protein S, Protein C and Protein Z. Deficiency of vitamin K (e.g. in malabsorption), use of inhibiting anticoagulants (warfarin, acenocoumarol and phenprocoumon) or disease (cirrhosis, hepatocellular carcinoma) impairs the function of the enzyme and leads to the formation of PIVKA's (proteins formed in vitamin K absence) this causes partial or non gamma carboxylation and affects the coagulation factors ability to bind to expressed phospholipid.

Three mechanisms keep the coagulation cascade in check. Abnormalities can lead to an increased tendency toward thrombosis: General Name, Symbol, Number calcium, Ca, 20 Chemical series alkaline earth metals Group, Period, Block 2, 4, s Appearance silvery white Atomic mass 40. ... Two schematic representations of a phospholipid. ... Vitamin K denotes a group of 2-methilo-naphthoquinone derivatives. ... A carboxyl or carboxylic group is a functional group consisting of a carbon atom and an oxygen atom doubly bonded to each other. ... Glutamic acid or glutamate (the anionic form of glutamic acid) is one of the 20 most common natural amino acids. ... Malabsorption is the state of impaired absorption of nutrients in the small intestine. ... Warfarin (also known under the brand names of Coumadin® and Marevan®) is an anticoagulant medication that is administered orally. ... Cirrhosis is a chronic disease of the liver in which liver tissue is replaced by connective tissue, resulting in the loss of liver function. ... Jump to: navigation, search When normal cells are damaged or old they undergo apoptosis; cancer cells, however, avoid apoptosis. ...

  • Protein C is an important co-factor inhibitor, which degrades the co-factors FVa and FVIIIa. It is activated by thrombin with thrombomodulin and requires its co-enzyme Protein S to function. Quantitative or qualitative deficiency of either may lead to thrombophilia (a tendency to develop thrombosis). Impaired action of Protein C (activated Protein C resistance), for example by Factor V, "Leiden" variant or high levels of FVIII also may lead to a thrombotic tendency.
  • Antithrombin is a serine protease inhibitor (serpin) that degrades the serine proteases; thrombin and FXa, as well as FXIIa, and FXIa. It is constantly active, but its adhesion to these factors is increased by the presence of heparan sulfate (a glycosaminoglycan) or the administration of heparins (different heparinoids increase affinity to F Xa, F IIa, or both). Quantitative or qualitative deficiency of antithrombin (inborn or acquired, e.g. in proteinuria) leads to thrombophilia.
  • Tissue factor pathway inhibitor (TFPI) inhibits F VIIa-related activation of F IX and F X after its original initiation.

Protein C is a major physiological anticoagulant. ... Thrombophilia is the propensity to develop thrombosis (blood clots) due to an abnormality in the system of coagulation. ... Factor V Leiden (sometimes Factor VLeiden) is a hypercoagulability disorder in which Factor V, one of the coagulation factors, cannot be deactivated. ... Antithrombin is a small molecule that inactivates several enzymes of the coagulation system. ... Serine protease inhibitors or serpins (short for serine protease inhibitor) are a group of proteins that inhibit peptidases (old name: proteases). ... Glycosaminoglycans (GAGs) are long unbranched polysaccharides, made up of repeating disaccharides that may be sulphated (e. ... Heparin - Wikipedia, the free encyclopedia /**/ @import /skins-1. ... Proteinuria (from protein and urine) means the presence of an excess of serum proteins in the urine. ...

Testing of coagulation

Numerous tests are used to assess the function of the coagulation system:

The contact factor pathway is initiated by activation of contact factors of plasma, and can be measured by the activated partial thromboplastin time (aPTT) test. The partial thromboplastin time (PTT) or activated partial thromboplastin time (aPTT) is a commonly performed test to measure the performance of both the intrinsic and the common coagulation pathways. ... The prothrombin time (PT) and its derived measures of prothrombin ratio (PR) and international normalized ratio (INR) are measures of the extrinsic pathway of coagulation. ... The prothrombin time (PT) and its derived measures of prothrombin ratio (PR) and international normalized ratio (INR) are measures of the extrinsic pathway of coagulation. ... This is a disambiguation page — a navigational aid which lists other pages that might otherwise share the same title. ... Bleeding time is a medical test done on someone to assess their platelet function. ... D-dimer is a blood test performed in the medical laboratory to diagnose thrombosis. ... The mixing test is a medical laboratory study used to clarify the differential diagnosis of clotting abnormalities. ... Antiphospholipid syndrome, or antiphospholipid antibody syndrome, is a disorder of coagulation, and causes thrombosis in both arteries and veins, as well as recurrent miscarriage. ... Factor V Leiden (sometimes Factor VLeiden) is a hypercoagulability disorder in which Factor V, one of the coagulation factors, cannot be deactivated. ... Thrombin (activated Factor II) is a coagulation protein that has many effects in the coagulation cascade. ... The partial thromboplastin time (PTT) or activated partial thromboplastin time (aPTT) is a commonly performed test to measure the performance of both the intrinsic and the common coagulation pathways. ...


The Tissue factor pathway is initiated by exposure of blood to "tissue factor" (a specific cellular lipoprotein), and can be measured by the prothrombin time (PT) test. This is reported as an INR value when used for the dosing of oral anticoagulants such as warfarin. The prothrombin time (PT) and its derived measures of prothrombin ratio (PR) and international normalized ratio (INR) are measures of the extrinsic pathway of coagulation. ... The prothrombin time (PT) and its derived measures of prothrombin ratio (PR) and international normalized ratio (INR) are measures of the extrinsic pathway of coagulation. ... Warfarin (also known under the brand names of Coumadin® and Marevan®) is an anticoagulant medication that is administered orally. ...


The quantatative and qualitative screening of fibrinogen is measured by the thrombin time (TCT). Measurement of the exact amount of fibrinogen present in the blood is generally done using the Clauss method for fibrinogen testing.


If a coagulation factor is part of the contact or tissue factor pathway, a deficiency of that factor will affect only one of the tests: thus hemophilia A, a deficiency of factor VIII, which is part of the contact factor pathway, results in an abnormally prolonged aPTT test but a normal PT test. The exceptions are prothrombin, fibrinogen and some variants of FX which can only be detected by either aPTT or PT. Haemophilia A (also spelt Hemophilia A or Hæmophilia A) is a blood clotting disorder caused by a mutation of the Factor VIII gene, leading to a deficiency in Factor VIII. It is the most common hemophilia. ...


Deficiencies of fibrinogen (quantitative or qualitative) will affect all screening tests.


Disorders of hemostasis

Idiopathic thrombocytopenic purpura is the condition of having a low platelet count (thrombocytopenia) of no known cause (idiopathic). ... Thrombotic thrombocytopenic purpura (TTP or Moschcowitz disease) is a rare disorder of the blood coagulation system that in most cases arises from the deficiency or inhibition of the enzyme responsible for cleaving von Willebrand factor. ... In medicine, Hemolytic-uremic syndrome (or haemolytic-uraemic syndrome, abbreviated HUS) is a disease characterised by microangiopathic hemolytic anemia, acute renal failure and a low platelet count (thrombocytopenia). ... Glanzmanns thrombasthenia is an extremely rare, autosomal recessive disorder of the blood, in which the platelets lack GPIIb/IIIa. ... Paroxysmal nocturnal hemoglobinuria (PNH) is a rare disease characterised by aplastic anemia, thrombosis and red urine in the morning due to breakdown of red blood cells. ... Disseminated intravascular coagulation (DIC) is a pathological process in the body where the blood starts to coagulate throughout the whole body. ... Haemophilia A (also spelt Hemophilia A or Hæmophilia A) is a blood clotting disorder caused by a mutation of the Factor VIII gene, leading to a deficiency in Factor VIII. It is the most common hemophilia. ... Haemophilia B (also spelled Hemophilia B or Hæmophilia B) is a blood clotting disorder caused by a mutation of the Factor IX gene. ... A mild form of hemophilia that mainly occurs in Jews of Ashkenazi descent. ... Von Willebrands disease (vWD) is the most common hereditary coagulation abnormality described in humans. ... Heparin-induced thrombocytopenia (HIT) with or without thombosis (HITT) is thrombocytopenia (low platelet counts) due to the administration of unfractionated heparin (UFH), it has also been observed with low molecular weight heparin (LMWH), danaparoid and related medication. ... Antiphospholipid syndrome (or antiphospholipid antibody syndrome) is a disorder of coagulation which causes thrombosis in both arteries and veins, as well as recurrent miscarriage. ... Factor V Leiden (sometimes Factor VLeiden) is a hypercoagulability disorder in which Factor V, one of the coagulation factors, cannot be deactivated. ... Thrombin (activated Factor II) is a coagulation protein that has many effects in the coagulation cascade. ... Protein S deficiency is a disorder associated with increased risk of thrombosis. ... Antithrombin is a small molecule that inactivates several enzymes of the coagulation system. ...

Coagulation factors

Coagulation factors and related substances
Number and/or name Function
I (fibrinogen) forms clot (fibrin)
II (prothrombin) its active form (IIa) activates I, V, VII, XIII, protein C, platelets
Tissue factor co-factor of VIIa (formerly known as factor III)
Calcium required for coagulation factors to bind to phospholipid (formerly known as factor IV)
V (proaccelerin, labile factor) co-factor of X with which it forms the prothrombinase complex
VI unassigned - old name of Factor Va
VII (stable factor) activates IX, X
VIII (antihemophilic factor) co-factor of IX with which it forms the tenase complex
IX (Christmas factor) activates X: forms tenase complex with factor VIII
X (Stuart-Prower factor) activates II: froms prothrombinase complex with factor V
XI (plasma thromboplastin antecedent) activates XII, IX and prekallikrein
XII (Hageman factor) activates prekallikrein and fibrinolysis
XIII (fibrin-stabilizing factor) crosslinks fibrin
von Willebrand factor binds to VIII, mediates platelet adhesion
prekallikrein activates XII and prekallikrein; cleaves HMWK
high molecular weight kininogen (HMWK) supports reciprocal activation of XII, XI, and prekallikrein
fibronectin mediates cell adhesion
antithrombin III inhibits IIa, Xa, and other proteases;
heparin cofactor II inhibits IIa, cofactor for heparin and dermatan sulfate ("minor antithrombin")
protein C inactivates Va and VIIIa
protein S cofactor for activated protein C (APC, inactive when bound to C4b-binding protein)
protein Z mediates thrombin adhesion to phospholipids and stimulates degradation of factor X by ZPI
Protein Z-related protease inhibitor (ZPI) degrades factors X (in presence of protein Z) and XI (independently)
plasminogen converts to plasmin, lyses fibrin and other proteins
alpha 2-antiplasmin inhibits plasmin
tissue plasminogen activator (tPA) activates plasminogen
urokinase activates plasminogen
plasminogen activator inhibitor-1 (PAI1) inactivates tPA & urokinase (endothelial PAI)
plasminogen activator inhibitor-2 (PAI2) inactivates tPA & urokinase (placental PAI)
cancer procoagulant pathological factor X activator linked to thrombosis in cancer

Fibrin is a protein involved in the clotting of blood. ... Thrombin (activated Factor II) is a coagulation protein that has many effects in the coagulation cascade. ... General Name, Symbol, Number calcium, Ca, 20 Chemical series alkaline earth metals Group, Period, Block 2, 4, s Appearance silvery white Atomic mass 40. ... Factor V is a protein of the coagulation system, rarely referred to as proaccelerin or labile factor. ... Factor VII (old name proconvertin) is one of the central proteins in the coagulation cascade. ... <<a href=b class=external free title=b>b>Factor VIII</<a href=b class=external free title=b>b> (FVIII) is an essential [clot]ting factor. ... Factor IX (or Christmas factor or Christmas-Eve factor) is one of the serine proteases (EC 3. ... Factor X, also known by the eponym Stuart-Prower factor or as thrombokinase, is an enzyme ( EC 3. ... Factor XI or plasma thromboplastin antecent is one of the enzymes ( EC 3. ... The Hageman factor, is a plasma protein now usually known as factor XII. It is part of the coagulation cascade and activates factor XI and prekallikrein. ... Fibrinolysis is the process where a fibrin clot, the product of coagulation, is broken down. ... Factor XIII or fibrin stabilizing factor is an enzyme (EC 2. ... Von Willebrand factor (vWF, also called Factor VIII-related antigen) is a blood protein of the coagulation system. ... High-molecular weight kininogen (HMWK), also known as the Williams-Fitzgerald-Flaujeac factor or the Fitzgerald factor is a protein from the blood coagulation system as well as the kinin-kallikrein system. ... Fibronectin is high molecular weight glycoprotein containing about 5% carbohydrate that bind to receptor proteins spanning the cell membrane called integrins and to the extracellular matrix. ... Antithrombin is a small molecule that inactivates several enzymes of the coagulation system. ... Protein C is a major physiological anticoagulant. ... Protein S is a vitamin K-dependent plasma glycoprotein synthesized in the liver and it functions as a cofactor to Protein C in the inactivation of Factors Va and VIIIa. ... Protein Z is a member of the coagulation cascade, the group of blood proteins that leads to the formation of blood clots. ... Protein Z-dependent protease inhibitor is a protein circulating in the blood which inhibits factors Xa and XIa of the coagulation cascade. ... Plasmin is an important degrading enzyme (EC 3. ... Alpha 2-antiplasmin (or α2-antiplasmin or plasmin inhibitor) is a serine protease inhibitor (serpin) responsible for inactivating plasmin, an important enzyme that participates in fibrinolysis and degradation of various other proteins. ... In blood coagulation, tissue plasminogen activator (tPA) is an enzyme (EC 3. ... Urokinase, also called urokinase-type Plasminogen Activator (uPA) is an enzyme (EC 3. ... Plasminogen activator inhibitor-1 is the principal inhibitor of tissue plasminogen activator (tPA) and urokinase (uPA), the activators of plasminogen and hence fibrinolysis (the physiological breakdown of blood clots). ... Human placenta shown a few minutes after birth. ... Cancer procoagulant is a hypothesised protein, most likely a cysteine protease enzyme (EC 3. ... Factor X, also known by the eponym Stuart-Prower factor or as thrombokinase, is an enzyme ( EC 3. ... Jump to: navigation, search When normal cells are damaged or old they undergo apoptosis; cancer cells, however, avoid apoptosis. ...

History

The exact process of coagulation was largely elucidated in the 20th century. At the end of the 19th century, it was presumed that the coagulation system consisted of four factors (Giangrande 2003): thrombokinase/thromboplastin (III, released by damaged tissues) - this reacted with prothrombin (II), which, together with calcium (IV), formed thrombin, which converted fibrinogen into fibrin (I). (19th century - 20th century - 21st century - more centuries) Decades: 1900s 1910s 1920s 1930s 1940s 1950s 1960s 1970s 1980s 1990s As a means of recording the passage of time, the 20th century was that century which lasted from 1901–2000 in the sense of the Gregorian calendar (1900–1999 in the... Jump to: navigation, search Calcium plays a vital role in the anatomy, physiology and biochemistry of organisms and of the cell, particularly in signal transduction pathways. ...


A first clue as to the complexity of the system of coagulation was the discovery of proaccelerin (initially and later called Factor V) by Paul Owren (1905-1990) in 1947. He also postulated that its function was the generation of accelerin (Factor VI), which later turned out to be the activated form of V (or Va); hence, VI is not now in active use.


Factor VII (also known as serum prothrombin conversion accelerator or proconvertin, precipitated by barium sulfate) was discovered in a young female patient in 1949 and 1951 by different groups. Factor VIII turned out to be deficient in the clinically recognised but etiologically elusive hemophilia A; it was identified in the 1950s and is alternatively called antihemophilic globulin due to its capability to correct hemophilia A. Haemophilia A (also spelt Hemophilia A or Hæmophilia A) is a blood clotting disorder caused by a mutation of the factor VIII gene, leading to a deficiency in Factor VIII. It is the most common hemophilia. ... Jump to: navigation, search // Events and trends The 1950s in Western society was marked with a sharp rise in the economy for the first time in almost 30 years and return to the 1920s-type consumer society built on credit and boom-times, as well as the height of the...


Factor IX was discovered in 1952 in a young patient with hemophilia B named Stephen Christmas (1947-1993). His deficiency was described by Dr. Rosemary Biggs and Professor R.G. MacFarlane in Oxford, UK. The factor is hence called Christmas Factor or Christmas Eve Factor. Christmas lived in Canada, and campaigned for blood transfusion safety until succumbing to transfusion-related AIDS at age 46. An alternative name for the factor is plasma thromboplastin component, given by an independent group in California. Haemophilia B (also spelled Hemophilia B or Hæmophilia B) is a blood clotting disorder caused by a mutation of the Factor IX gene. ... Stephen Christmas (1947-1993) was a 5 year old boy when he became the first patient described to have Christmas disease (or Haemophilia B) in 1952 by a group of British doctors. ... Jump to: navigation, search The Red Ribbon is the global symbol for solidarity with HIV positive and people living with AIDS. The Red Ribbon made its public debut when host Jeremy Irons wore it during the 1991 Tony Awards. ...


Hageman factor, now known as factor XII, was identified in 1955 in an asymptomatic patient with a prolonged bleeding time named of John Hageman. Factor X, or Stuart-Prower factor, followed, in 1956. This protein was identified in a Ms. Audrey Prower of London, who had a lifelong bleeding tendency. In 1957, an American group identified the same factor in a Mr. Rufus Stuart. Factors XI and XIII were identified in 1953 and 1961, respectively.


The usage of Roman numerals rather than eponyms or systematic names was agreed upon during annual conferences (starting in 1955) of hemostasis experts. This committee evolved into the present-day International Committee on Thrombosis and Hemostasis (ICTH). Assignment of numerals ceased in 1963 after the naming of Factor XIII. The names Fletcher Factor and Fitzgerald Factor were given to further coagulation-related proteins, namely prekallikrein and high molecular weight kininogen respectively. The system of Roman numerals is a numeral system originating in ancient Rome, and was adapted from Etruscan numerals. ... High-molecular weight kininogen (HMWK), also known as the Williams-Fitzgerald-Flaujeac factor or the Fitzgerald factor is a protein from the blood coagulation system as well as the kinin-kallikrein system. ...


Factors III and VI are unassigned, as thromboplastin was never identified, and actually turned out to consist of ten further factors, and accelerin was found to be activated Factor V.


References

  • Giangrande PL. Six characters in search of an author: the history of the nomenclature of coagulation factors. Br J Haematol 2003;121:703-12. PMID 12780784.


Cardiovascular system - Blood
Red blood cells - White blood cells - Platelets - Blood plasma
White blood cells
Granulocytes (Neutrophil granulocytes, Eosinophil granulocytes, Basophil granulocytes) - Lymphocytes - Monocytes
Coagulation
Coagulation factors: - Fibrin (I) - (Pro)thrombin (II) - FV - FVII - FVIII - FIX - FX - FXI - FXII - FXIII - HMWK - vWF - Tissue factor
Inhibitors: Antithrombin - Protein C - Protein S - Protein Z - ZPI - TFPI
Fibrinolysis: Plasmin - tPA/urokinase - PAI-1/2 - α2-AP - TAFI

  Results from FactBites:
 
Coagulation - Wikipedia, the free encyclopedia (2130 words)
Coagulation is similar in all mammals, but as most is known about the system in humans, this article focuses on human blood coagulation.
Coagulation factors are generally indicated by Roman numerals, with a lowercase a appended to indicate an active form, ultimately resulting in cross-linked fibrin.
If a coagulation factor is part of the contact or tissue factor pathway, a deficiency of that factor will affect only one of the tests: thus hemophilia A, a deficiency of factor VIII, which is part of the contact factor pathway, results in an abnormally prolonged aPTT test but a normal PT test.
  More results at FactBites »

 
 

COMMENTARY     


Share your thoughts, questions and commentary here
Your name
Your comments

Want to know more?
Search encyclopedia, statistics and forums:

 


Press Releases |  Feeds | Contact
The Wikipedia article included on this page is licensed under the GFDL.
Images may be subject to relevant owners' copyright.
All other elements are (c) copyright NationMaster.com 2003-5. All Rights Reserved.
Usage implies agreement with terms, 1022, m