tissue factor

factor /fac·tor/ (fak´ter) an agent or element that contributes to the production of a result.

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accelerator factor  coagulation f. V.

angiogenesis factor  a substance that causes the growth of new blood vessels, found in tissues with high metabolic requirements and also released by macrophages to initiate revascularization in wound healing.

antihemophilic factor  (AHF)

1. coagulation f. VIII.

2. a preparation of factor VIII used for the prevention or treatment of hemorrhage in patients with hemophilia A and the treatment of von Willebrand disease, hypofibrinogenemia, and factor XIII deficiency, including preparations derived from human or porcine plasma or by recombinant technology.

antihemophilic factor A  coagulation f. VIII.

antihemophilic factor B  coagulation f. IX.

antihemophilic factor C  coagulation f. XI.

antinuclear factor  (ANF) see under antibody.

factor B  a complement component that participates in the alternative complement pathway.

B cell differentiation factors  (BCDF) factors derived from T cells that stimulate B cells to differentiate into antibody-secreting cells.

B lymphocyte stimulatory factors  (BSF) a system of nomenclature for factors that stimulate B cells, replacing individual factor names with the designation BSF and an appended descriptive code.

Christmas factor  coagulation f. IX.

C3 nephritic factor  (C3 NeF) an autoantibody that stabilizes the alternative complement pathway C3 convertase, preventing its inactivation by factor H and resulting in complete consumption of plasma C3; it is found in the serum of many patients with type II membranoproliferative glomerulonephritis.

coagulation factors  substances in the blood that are essential to the clotting process and hence, to the maintenance of normal hemostasis. They are designated by Roman numerals, to which the notation “a” is added to indicate the activated state. See also platelet f's .

factor I fibrinogen: a high-molecular-weight plasma protein converted to fibrin by the action of thrombin. Deficiency results in afibrinogenemia or hypofibrinogenemia.

factor II prothrombin: a plasma protein converted to thrombin by activated factor X in the common pathway of coagulation. Deficiency leads to hypoprothrombinemia.

factor III tissue thromboplastin: a lipoprotein functioning in the extrinsic pathway of coagulation, activating factor X.

factor IV calcium.

factor V proaccelerin: a factor functioning in both the intrinsic and extrinsic pathways of coagulation, catalyzing the cleavage of prothrombin to thrombin. Deficiency leads to parahemophilia.

factor VII proconvertin: a factor functioning in the extrinsic pathway of blood coagulation, acting with factor III to activate factor X. Deficiency, either hereditary or associated with vitamin K deficiency, leads to hemorrhagic tendency.

factor VIII antihemophilic factor (AHF): a storage-labile factor participating in the intrinsic pathway of blood coagulation, acting as a cofactor in the activation of factor X. Deficiency, an X-linked recessive trait, causes hemophilia A.

factor IX a relatively storage-stable substance involved in the intrinsic pathway of blood coagulation, activating factor X. Deficiency results in the hemorrhagic syndrome hemophilia B, resembling hemophilia A; it is treated with purified preparations of the factor, either from human plasma or recombinant, or with factor IX complex.

factor X Stuart factor: a storage-stable factor that participates in both the intrinsic and extrinsic pathways of blood coagulation, uniting them to begin the common pathway of coagulation; as part of the prothrombinase complex, activated factor X activates prothrombin. Deficiency may cause a systemic coagulation disorder. The activated form is called also thrombokinase.

factor XI plasma thromboplastin antecedent: a stable factor involved in the intrinsic pathway of blood coagulation, activating factor IX. Deficiency results in the blood-clotting defect hemophilia C.

factor XII Hageman factor: a stable factor activated by contact with glass or other foreign surfaces, which initiates the intrinsic process of blood coagulation by activating factor XI.

factor XIII fibrin-stabilizing factor: a factor that polymerizes fibrin monomers, enabling formation of a firm blood clot. Deficiency produces a clinical hemorrhagic diathesis.

colony-stimulating factors  a group of glycoprotein lymphokines, produced by blood monocytes, tissue macrophages, and stimulated lymphocytes and required for the differentiation of stem cells into granulocyte and monocyte cell colonies; they stimulate the production of granulocytes and macrophages and have been used experimentally as cancer agents.

factor D  a serine protease of the alternative complement pathway that cleaves factor B bound to C3b, releasing Ba while leaving Bb bound to C3b to form the C3 convertase C3bBb.

decay accelerating factor  (DAF) a protein of most blood cells as well as endothelial and epithelial cells, CD55; it protects the cell membranes from attack by autologous complement.

endothelial-derived relaxant factor , endothelium-derived relaxing factor (EDRF) nitric oxide.

extrinsic factor  cyanocobalamin.

F (fertility) factor  F plasmid.

fibrin-stabilizing factor  (FSF) coagulation f. XIII.

Fitzgerald factor  high-molecular-weight kininogen.

Fletcher factor  prekallikrein.

glucose tolerance factor  a biologically active complex of chromium and nicotinic acid that facilitates the reaction of insulin with receptor sites on tissues.

granulocyte colony-stimulating factor  (G-CSF) a colony-stimulating factor that stimulates the production of neutrophils from precursor cells.

granulocyte-macrophage colony-stimulating factor  (GM-CSF) a colony-stimulating factor that binds to stem cells and most myelocytes and stimulates their differentiation into granulocytes and macrophages.

growth factor  any substance that promotes skeletal or somatic growth, usually a mineral, hormone, or vitamin.

factor H  a glycoprotein that acts as an inhibitor of the alternative pathway of complement activation.

Hageman factor  (HF) coagulation f. XII.

histamine-releasing factor  (HRF) a lymphokine that induces the release of histamine by IgE-bound basophils in late phase allergic reaction.

homologous restriction factor  (HRF) a regulatory protein that binds to the membrane attack complex in autologous cells, inhibiting the final stages of complement activation.

factor I  a plasma enzyme that regulates both classical and alternative pathways of complement activation by inactivating their C3 convertases.

inhibiting factors  factors elaborated by one body structure that inhibit release of hormones by another structure; applied to substances of unknown chemical structure, while those of established chemical identity are called inhibiting hormones.

insulinlike growth factors  (IGF) insulin-like substances in serum that do not react with insulin antibodies; they are growth hormone–dependent and possess all the growth-promoting properties of the somatomedins.

intrinsic factor  a glycoprotein secreted by the parietal cells of the gastric glands, necessary for the absorption of vitamin B12. Lack of intrinsic factor, with consequent deficiency of vitamin B12, results in pernicious anemia.

LE factor  an antinuclear antibody having a sedimentation rate of 7S and reacting with leukocyte nuclei, found in the serum in systemic lupus erythematosus.

leukocyte inhibitory factor  (LIF) a lymphokine that prevents polymorphonuclear leukocytes from migrating.

lymph node permeability factor  (LNPF) a substance from normal lymph nodes which produces vascular permeability.

lymphocyte mitogenic factor  (LMF) a nondialyzable heat-stable macromolecule released by lymphocytes stimulated by a specific antigen; it causes blast transformation and cell division in normal lymphocytes.

lymphocyte transforming factor  (LTF) a lymphokine causing transformation and clonal expansion of nonsensitized lymphocytes.

myocardial depressant factor  (MDF) a peptide formed in response to a fall in systemic blood pressure; it has a negatively inotropic effect on myocardial muscle fibers.

osteoclast activating factor  (OAF) a lymphokine produced by lymphocytes which facilitates bone resorption.

factor P  properdin.

platelet factors  factors important in hemostasis which are contained in or attached to the platelets.

platelet factor 1 adsorbed coagulation factor V from the plasma.

platelet factor 2 an accelerator of the thrombin-fibrinogen reaction.

platelet factor 3 a lipoprotein with roles in the activation of both coagulation factor X and prothrombin.

platelet factor 4 an intracellular protein component of blood platelets capable of inhibiting the activity of heparin.

platelet activating factor  (PAF) an immunologically produced substance which is a mediator of clumping and degranulation of blood platelets and of bronchoconstriction.

platelet-derived growth factor  a substance contained in the alpha granules of blood platelets whose action contributes to the repair of damaged blood vessel walls.

R factor  see under plasmid.

releasing factors  factors elaborated in one body structure that cause release of hormones from another structure; applied to substances of unknown chemical structure, while those of established chemical identity are called releasing hormones.

resistance transfer factor  (RTF) the portion of an R plasmid containing the genes for conjugation and replication.

Rh factor , Rhesus factor genetically determined antigens present on the surface of erythrocytes; incompatibility for these antigens between mother and offspring is responsible for erythroblastosis fetalis.

rheumatoid factor  (RF) a protein (IgM) detectable by serological tests, which is found in the serum of most patients with rheumatoid arthritis and in other related and unrelated diseases and sometimes in apparently normal persons.

risk factor  a clearly defined occurrence or characteristic that has been associated with the increased rate of a subsequently occurring disease.

Stuart factor , Stuart-Prower factor coagulation f. X.

tissue factor  coagulation f. III.

transforming growth factor  (TGF) any of several proteins secreted by transformed cells and causing growth of normal cells, although not causing transformation.

tumor necrosis factor  either of two lymphokines that cause hemorrhagic necrosis of certain tumor cells but do not affect normal cells; they have been used as experimental anticancer agents. Tumor necrosis factor α (formerly cachectin ) is produced by macrophages, eosinophils, and NK cells. Tumor necrosis factor β, is lymphotoxin.

vascular endothelial growth factor  (VEGF), vascular permeability factor (VPF) a peptide factor that is a mitogen of vascularendothelial cells; it promotes tissue vascularization and is important in tumor angiogenesis.

von Willebrand's factor  (vWF) a glycoprotein that circulates complexed to coagulation factor VIII, mediating adhesion of platelets to damaged epithelial surfaces. Deficiency results in von Willebrand's disease.

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Tissue factor

A glycoprotein involved in blood coagulation.

Mentioned in: Hemorrhagic Fevers

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tissue

a group or layer of similarly specialized cells that together perform certain special functions. For anatomically specific tissues see under their identifying titles, e.g. adipose, connective.

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tissue death

see necrosis.

tissue density

the penetrability of tissue by x-rays, bone and tooth being most dense, blood and soft tissue the next, fat the next, and gas and air least.

tissue edema

an abnormal accumulation of tissue fluid.

tissue factor

see tissue thromboplastin.

tissue fluid

the extracellular fluid that constitutes the environment of the body cells. It is low in protein, is formed by filtration through the capillaries, and the excess drains away as lymph. See also interstitial fluid.

tissue inhibitors

inhibitors of fibrinolysis; present in placenta.

indifferent tissue

undifferentiated embryonic tissue.

tissue necrosis fever

fever caused by pyrogens released by necrotic pyrogens.

tissue plasminogen activator

see plasminogen activator.

tissue reacting agent

substances that have a poorly defined but advantageous local effect on tissues.

tissue receptor site

a cell receptor common to cells of a particular tissue.

tissue residue

residues of chemical substances that are unacceptable to local pure food legislation especially sulfonamides, estrogens, chlorinated hydrocarbons, heavy metals. These are thought or known to have a deleterious effect on people eating or drinking the relevant animal product. See also chemical food residue.

tissue sensitivity

the susceptibility of individual tissues to injury by x-ray. The injury may be by way of inflammation, necrosis or cessation of cell growth. Fast-growing tissues in which the cells have a high mitotic index are the most sensitive, especially gonads, germinative layer of skin and erythropoietic tissues.

supportive t's

cartilage and bone.

tissue therapy

see glandular therapy.

tissue typing

identification of tissue types for purposes of predicting acceptance or rejection of grafts and organ transplants. The process and purposes of tissue typing are essentially the same as for blood typing. The major difference lies in the kinds of antigens being evaluated. White blood cells, particularly lymphocytes, are used for tissue typing. The acceptance of allografts depends particularly on the matching of MHC antigens. If the donor and recipient are not MHC identical, the allograft is rejected. See also typing.

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tissue factor

Coagulation factor III, factor III, thromboplastin Hematology A complex of phosphatides, lipoproteins, and cholesterol, that accelerates coagulation, which is obtained from homogenates of human tissue