growth 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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growth factor

n.

A substance that affects the growth of an organism.

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Growth factor

A local hormone produced by some cells that initiates growth.

Mentioned in: Neuroendocrine Tumors

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growth factor,

any protein that stimulates the division and differentiation of specific types of cells. Growth factors include platelet-derived growth factor; epidermal growth factor; nerve growth factor; and interleukins, a group of at least 15 proteins produced mainly by T cells but also by mononuclear phagocytes and other cells. Growth factors specifically involved in the division and differentiation of bone marrow stem cells are classified as colony-stimulating factors. Platelets are a rich source of growth factors, some of which may be involved in the cellular proliferation that occurs in diseases such as rheumatoid arthritis and glomerulonephritis. See also cytokine.

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growth,

n an increase in size.

growth and development,

n the process of
growth is defined as an increase in size;
development is defined as a progression toward maturity. Thus the terms are used together to describe the complex physical, mental, and emotional processes associated with the “growing up” of children.

growth factor,

n the chemical messengers that induce cell growth by tissue type (e.g., osteoinductive factor, epidermal growth factors).

growth failure,

n a lack of normal physical and psychologic development as a result of genetic, nutritional, pathologic, or psychosocial factors. See also failure to thrive.

growth, grain,

n a phenomenon resulting from heat treatment of alloys. In excessive amounts, this growth produces undesirable physical properties.

growth hormone (GH),

n a single-chain peptide secreted by the anterior pituitary gland in response to growth hormone releasing factor (GHRF) from the hypothalamus. Growth hormone promotes protein synthesis in all cells, increased fat mobilization and use of fatty acids for energy, and decreased use of carbohydrates.

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growth

1. the progressive increase in size of a living thing, especially the process by which the body reaches its point of complete physical development.

2. an abnormal formation of tissue, such as a tumor.

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growth arrest line

a radiologically detectable line parallel to the growth plate in the metaphysis that indicates a temporary cessation of bone growth.

growth check

an event or state, usually the result of inadequate nutrition, parasitism or other disease, which temporarily reduces or stops growth in a young animal. Often followed by a period of compensatory growth.

compensatory growth

increased growth rate during a time period as a result of lower than normal growth rate during a previous period.

growth cone

bulbous enlargement at the tip of every growing axonal fiber in the fetus, from which many long filapodia extend.

growth curve

the curve obtained by plotting increase in size or numbers against the elapsed time.

growth disorders

are sometimes traceable to excess or shortage of pituitary secretions, and may arise from hereditary defects or from glandular abnormalities. Abnormally large secretions of growth hormone can produce gigantism. Failure of the pituitary gland to develop sufficiently or to secrete adequate amounts of growth hormone may result in dwarfism. In adulthood, overproduction of growth hormone may lead to acromegaly.

growth factor

substances which act as local regulators of cell division and function; classified as autocrine (act on cells of the same class) or paracrine (act on cells of a different class).

hematopoietic growth factors

see colony-stimulating factors.

one-step growth curve

a plot typical of the rapid growth of a virus in cell culture when all cells are infected simultaneously.

growth plate

the epiphyseal cartilage at which new bone formation occurs to lengthen long bones during their growth phase. Called also physis. See also epiphyseal plate.

growth promotants

includes all agents used to increase the rate of body weight gain. Used principally in food animals but also in horses with a view to increasing muscle mass and physical performance, and in any species to hasten recuperation in animals debilitated by illness. Pharmaceutical preparations are principally anabolic steroids. Husbandry procedures include estrogen and zearalenone implants and dietary supplementation with antibiotics, monensin and, in the case of pigs, copper.

growth rate

rate of increase in body weight per unit of time, e.g. lb/day in beef cattle.

recombinant growth factor

recombinant growth hormone.

growth retardation

stature smaller than normal; called also runt.

growth retardation lattice

radiodense metaphyseal lines parallel to the epiphyseal plate developing in fetal bone.

transforming growth factor [beta]

a family of extracellular signaling molecules important in the transformation of cells and in growth and development.

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growth factor

Any natural cytokine that facilitates cell division and proliferation, which are produced by normal cells during embryonic development, tissue growth, and wound healing Examples EGF, erythropoietin, fibroblast growth factor, IGF-I, IGF-II, nerve growth factor, PDGF, relaxin, somatomedins A and B, TGF-α. See Cytokine, Transforming growth factor.