factor

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factor

 [fak´ter]
an agent or element that contributes to the production of a result.
accelerator factor factor V, one of the coagulation factors.
factor I see coagulation factors.
factor II see coagulation factors.
factor III see coagulation factors.
factor IV see coagulation factors.
factor V see coagulation factors.
factor VI see coagulation factors.
factor VII see coagulation factors.
factor VIII see coagulation factors.
factor IX see coagulation factors.
factor X see coagulation factors.
factor XI see coagulation factors.
factor XII see coagulation factors.
factor XIII see coagulation factors.
angiogenesis factor a substance that causes the growth of new blood vessels, found in tissues with high metabolic requirements such as cancers and the retina. It is also released by hypoxic macrophages at the edges or outer surface of a wound and initiates revascularization in wound healing.
antihemophilic factor (AHF)
2. a preparation of factor VIII administered intravenously for the prevention or treatment of hemorrhage in patients with hemophilia A and the treatment of von Willebrand disease, hypofibrinogenemia, and coagulation factor XIII deficiency. Included are preparations derived from human plasma (antihemophilic factor, cryoprecipitated antihemophilic factor) or porcine plasma (antihemophilic factor [porcine]) and those produced by recombinant technology antihemophilic factor [recombinant]).
antihemophilic factor A factor VIII, one of the coagulation factors.
antihemophilic factor B factor IX, one of the coagulation factors.
antihemophilic factor C factor XI, one of the coagulation factors.
antihemorrhagic factor vitamin K.
antinuclear factor (ANF) antinuclear antibody.
antirachitic factor vitamin D.
atrial natriuretic factor (ANF) a hormone produced in the cardiac atrium; an inhibitor of renin secretion and thus of the production of angiotensin, and a stimulator of aldosterone release. Its effect is increased excretion of water and sodium and a lowering of blood pressure.
factor B a complement component that participates in the alternative complement pathway.
blastogenic factor lymphocyte-transforming factor.
carative f's in the theory of human caring, a set of ten factors that offer a descriptive topology of interventions including (1) a humanistic-altruistic system of values; (2) faith-hope; (3) sensitivity to self and others; (4) a helping-trusting, human care relationship; (5) the expression of positive and negative feelings; (6) a creative problem-solving caring process; (7) transpersonal teaching and learning; (8) a supportive, protective, and/or corrective mental, physical, societal, and spiritual environment; (9) human needs assistance; and (10) existential-phenomenological-spiritual forces.
Christmas factor factor IX, one of the coagulation factors.
citrovorum factor folinic acid.
clotting f's coagulation factors.
C3 nephritic factor (C3 NeF) an autoantibody that stabilizes the alternative complement pathway C3 convertase, preventing its inactivation by factor h, resulting in complete consumption of plasma C3; it is found in the serum of many patients with type II membranoproliferative glomerulonephritis.
coagulation f's see coagulation factors.
colony-stimulating factor (CSF) any of a number of glycoproteins responsible for the proliferation, differentiation, and functional activation of hematopoietic progenitor cells; specific factors are named for the cell lines that they stimulate. Used to promote bone marrow proliferation in aplastic anemia, following cytotoxic chemotherapy, or following bone marrow transplantation. Types include granulocyte, granulocyte-macrophage, and macrophage colony-stimulating factors.
factor D a factor that when activated serves as a serine esterase in the alternative complement pathway.
decay accelerating factor (DAF) a protein of most blood as well as endothelial and epithelial cells, CD55 (see CD antigen); it protects the cell membranes from attack by autologous complement.
endothelial-derived relaxant factor (endothelial-derived relaxing factor) (endothelium-derived relaxing factor (EDRF)) nitric oxide.
extrinsic factor cyanocobalamin.
F factor (fertility factor) F plasmid.
fibrin-stabilizing factor (FSF) factor XIII, one of the coagulation factors.
Fletcher factor prekallikrein.
granulocyte colony-stimulating factor (G-CSF) a colony-stimulating factor that stimulates 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 complement system regulatory protein that inhibits the alternative pathway of complement activation.
Hageman factor (HF) factor XII, one of the coagulation factors. See illustration.
Activation of Hageman factor (factor XII) leads to increased vascular permeability, clotting, and thrombolysis. From Damjanov, 2000.
hematopoietic growth f's a group of substances with the ability to support hematopoietic colony formation in vitro, including erythropoietin, interleukin-3, and colony-stimulating factors. All except erythropoietin stimulate mature cells, have overlapping capabilities to affect progenitor cells of several blood cell lines, and also affect cells outside the hematopoietic system.
histamine-releasing factor (HRF) a lymphokine, believed to be produced by macrophages and B lymphocytes, that induces the release of histamine by IgE-bound basophils. It occurs in late phase allergic reaction, six or more hours after contact with the antigen, in sensitive individuals.
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.
immunoglobulin-binding factor (IBF) a lymphokine having the ability to bind IgG complexed with antigen and prevent complement activation.
insulinlike growth f's (IGF) insulinlike 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.
intensification factor in radiology, the comparative increase in light transmission when films are exposed in the presence of intensifying screens compared to that in the absence of screens.
intrinsic factor a glycoprotein secreted by the parietal cells of the gastric glands, necessary for the absorption of cyanocobalamin (vitamin B12). Its absence results in pernicious anemia.
LE factor an immunoglobulin that reacts with leukocyte nuclei, found in the serum in systemic lupus erythematosus.
lymph node permeability factor (LNPF) a substance from normal lymph nodes that produces vascular permeability.
lymphocyte mitogenic factor (LMF) (lymphocyte-transforming factor) a substance that is released by lymphocytes stimulated by specific antigen and causes nonstimulated lymphocytes to undergo blast transformation and cell division; called also blastogenic factor.
macrophage-activating factor (MAF) interferon-α.
macrophage colony-stimulating factor (M-CSF) a colony-stimulating factor secreted by macrophages, stimulated endothelial cells, and most tissues, that stimulates the production of macrophages from precursor cells and maintains the viability of mature macrophages in vitro.
macrophage chemotactic factor (MCF) a lymphokine that attracts macrophages to the invasion site.
macrophage-derived growth factor a substance released by macrophages below the surface of a wound that induces the proliferation of fibroblasts.
macrophage inhibition factor (macrophage inhibitory factor) migration inhibitory factor.
migration inhibition factor (migration inhibitory factor) a lymphokine that inhibits macrophage migration.
minification factor in radiology, the gain in light achieved by a reduction in size of the output phosphor from the input phosphor size.
osteoclast-activating factor (OAF) a lymphokine that stimulates bone resorption; it may be involved in the bone resorption associated with multiple myeloma and other hematologic neoplasms or inflammatory disorders such as rheumatoid arthritis and periodontal disease.
factor P properdin.
platelet f's see platelet factors.
platelet-activating factor (PAF) a substance released by basophils and mast cells in immediate hypersensitivity reactions, and by macrophages and neutrophils in other inflammatory reactions; it leads to bronchoconstriction, platelet aggregation, and release of vasoactive substances from platelets.
platelet-derived growth factor a substance contained in platelets and capable of inducing proliferation of vascular endothelial cells, vascular smooth muscle cells, fibroblasts, and glial cells; its action contributes to the repair of damaged vascular walls.
R factor R plasmid.
releasing f's factors elaborated in one structure (as in the hypothalamus) that effect the release of hormones from another structure (as from the anterior pituitary gland), including corticotropin-releasing factor, melanocyte-stimulating hormone–releasing factor, and prolactin-releasing factor. Applied to substances of unknown chemical structure, while substances of established chemical identity are called releasing hormones.
resistance factor R f.
Rh factor a type of agglutinogen found on some erythrocytes; see also rh factor.
rheumatoid factor (RF) antibodies directed against antigenic determinants on IgG molecules, found in the serum of about 80 per cent of patients with classic or definite rheumatoid arthritis; but in only about 20 per cent of patients with juvenile rheumatoid arthritis; rheumatoid factors may be IgM, IgG, or IgA antibodies, although serologic tests measure only IgM. Rheumatoid factors also occur in other connective tissue diseases and infectious diseases.
risk factor an agent or situation that is known to make an individual or population more susceptible to the development of a specific negative condition.
risk factor (omaha) an environmental, psychosocial, or physiologic event or health related behavior that increases the client's exposure or vulnerability to the development of a client problem; the nurse's knowledge base of risk factors is used to identify potential problem modifiers in the Problem Classification scheme of the omaha system.
stable factor factor VII, one of the coagulation factors.
Stuart factor (Stuart-Prower factor) factor X, one of the coagulation factors.
sun protection factor (SPF) a numerical rating of the amount of protection afforded by a sunscreen; the higher the number, the more protection is provided.
tissue factor factor III, one of the coagulation factors.
transfer factor (TF) a factor occurring in sensitized lymphocytes that can transfer delayed hypersensitivity to a formerly nonreactive individual; see also transfer factor.
tumor necrosis factor (TNF) either of two lymphokines produced primarily by cells of the immune system, capable of causing in vivo hemorrhagic necrosis of certain tumor cells but not normal cells. They also destroy cells associated with the inflammatory response. They have been used as experimental anticancer agents but can also induce shock when bacterial endotoxins cause their release. Tumor necrosis factor α, formerly called cachectin, contains 157 amino acids and is produced by macrophages, eosinophils, and NK cells. Tumor necrosis factor β is lymphotoxin and contains 171 amino acids.
vascular endothelial growth factor (VEGF) (vascular permeability factor (VPF)) a peptide factor that stimulates the proliferation of cells of the endothelium of blood vessels; it promotes tissue vascularization and is important in blood vessel formation in tumors.
von Willebrand's factor (vWF) a glycoprotein synthesized in endothelial cells and megakaryocytes that circulates complexed to coagulation factor VIII. It is involved in adhesion of platelets to damaged epithelial surfaces and may participate in platelet aggregation. Deficiency results in the prolonged bleeding time seen in von Willebrand's disease.

fac·tor

(fak'tŏr),
1. One of the contributing causes in any action.
2. One of the components that by multiplication makes up a number or expression.
3. Synonym(s): gene
4. A vitamin or other essential element.
5. An event, characteristic, or other definable entity that brings about a change in health.
6. A categoric independent variable, used to identify, by means of numeric codes, membership in a qualitatively identifiable group; for example, overcrowding is a factor in disease transmission.
[L. maker, causer, fr. facio, to make]

factor

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

factor

(făk′tər)
n.
1. A quantity by which a stated quantity is multiplied or divided, so as to indicate an increase or decrease in a measurement: The rate increased by a factor of ten.
2. Physiology A substance that functions in a specific biochemical reaction or bodily process, such as blood coagulation.
v. fac·tored, fac·toring, fac·tors
tr.v.
To determine or indicate explicitly the factors of: If you factor 70, you get 2, 5, and 7.
intr.v.
To engage in purchasing accounts receivable at a discount.

fac′tor·a·ble adj.
fac′tor·ship′ n.

factor

1 one of a number of elements contributing to a whole.
2 a number by which another number is exactly divisible.
3 one of a number of elements that affect a specific result.

factor

A substance or activity that produces a result or outcome Clinical research
1. In analysis of variance, an independent variable–ie, a variable presumed to cause or influence another variable.
2. In factor analysis, a cluster of related variables distinguishable from a larger set of variables.
3. A number by which another number is multiplied, as in the statement: real estate values ↑ by a factor of 3–ie, tripled Medtalk A molecule or substance known to exist in a system, which is poorly characterized when the system is first described; with time, the molecules may be identified and/or sequenced, such that the original 'factor' designation may fall into disfavor and retain historic interest. See Act of smoking factor, Age/sex factor, Angiogenic factor, Antitermination factor, ARF factor, Atrial systolic factor, Autocrine motility factor, Basal factor, Bioaccumulation factor, Bioconcentration factor, Brain-derived neutrophic factor, Causal factor, Chemotactic factor, Co-carcinogenic K factor, Colonization factor, Colony-stimulating factor, Contact inhibiting factor, Conversion factor, Cord factor, DAF factor, Dilution factor, Elongation factor, Environmental factor, Epidermal growth factor, Faith factor, Father factor, Fibroblast growth factor, Fuzz factor, GAGA factor, GATA-1 factor, Glial cell-derived neurotrophic factor, Growth factor, Growth hormone factor, GM-CSF factor, Hageman factor, Hanukkah factor, Harmonic factor, Hassle factor, Heparin-binding fibroblast growth factor, Heparin cofactor II, Hepatocyte growth factor, HGF/SF factor, Horizontal scaling factor, Host factor, Human factor, IGF-I, IGF-II, Initiation factor, Integration host factor, Intrinsic factor, IRF-1 factor, Keratinocyte growth factor, Leukemia inhibitory factor, Leukocyte inhibitory factor, Macrophage activating factor, Macrophage chemotactic factor, Macrophage/monocyte inhibitory factor, Magic factor, Male factor, Mast cell growth factor, Mesoderm-inducing factor, Methuselah factor, Migration inhibition factor, Mitochondrial transcription factor, Monocyte colony inhibitory factor, Motivational factor, Motor neuron growth factor, MPF factor, Myocardial depressant factor, Nerve growth factor, Neurotrophic factor, Nuclear roundness factor, Osteoclast-activating factor, Ovarian factor, Partitioning factor, Partner risk factor, Peptide supply factor, Personal risk factor, Platelet factor, Platelet-activating factor, Platelet-derived growth factor, Prognostic factor, R factor, Release factor, Replication licensing factor, Resistance transfer factor, Rheumatoid factor, Rho factor, Risk factor, S factor, Safety factor, Satiation factor, Scatter factor, Serum spreading factor, Shrinkage factor, Sigma factor, Smooth muscle cell-derived growth factor, Sociodemographic factor, Soft risk factor, Somalia factor, Stem cell factor, Stringent factor, Stromal-cell-derived factor 1, Sun protection factor, Suppressive factor, Testis-determining factor, Thymic factor, Thymic humoral factor, Tissue factor, Transcription factor, Transforming growth factor, Trend factor, Trigger factor, Trypanosome lytic factor, Tumor necrosis factor, Uncertainty factor, Upstream binding factor, Uterine factor, V factor, Vascular endothelial growth factor, Vascular integrity factor, Vascular permeability factor, Von Willebrand factor, Windchill factor, X factor, Yates correction factor.

fac·tor

(fak'tŏr)
1. A contributing cause in any action.
2. One of the components that, by multiplication, make up a number or expression.
3. Synonym(s): gene.
4. A vitamin or other essential element.
5. An event, characteristic, or other definable entity that brings about a change in a health condition.
6. A categoric independent variable used to identify, by means of numeric codes, membership in a qualitatively identifiable group (e.g., "overcrowding is a factor in disease transmission.").
[L. maker, causer, fr. facio, to make]

factor

1. Any kind of biological material that causes a particular effect.
2. An effector whose function is known but which has not yet been chemically identified.
3. One of the components in the blood coagulation cascade.

Factor

Any of several substances necessary to produce a result or activity in the body. The term is used when the chemical nature of the substance is unknown. In endocrinology, when the chemical nature is known, factors are renamed hormones.
Mentioned in: Prolactin Test

fac·tor

(fak'tŏr)
A contributing cause in any action.
[L. maker, causer, fr. facio, to make]

factor(s),

n a constituent, element, cause, or agent that influences a process or system; a gene; a dietary substance.
factor I (fibrinogen, profibrin),
n See fibrinogen.
factor II (prothrombin, component A, prothrombase, prothrombin B, thrombogen, thrombozyme),
n considered the only essential precursor of thrombin.
factor III (thromboplastin [tissue], thrombokinase, cytozyme platelet], thrombokinin [blood], thromboplastic protein),
factor IV (calcium, Ca),
n ionized and/or bound calcium, generally required for the coagulation of blood, although some early phases of coagulation and the thrombin-fibrinogen reaction can take place without calcium.
factor V (labile factor, proaccelerin, accelerin, acceleration factor, cofactor of thromboplastin, component A of prothrombin, plasma ac-globulin, plasma prothrombin conversion factor [PPCF], prothrombinase, prothrombin accelerator, prothrombin conversion accelerator I, thrombogen, thrombogene, proaccelerinaccelerin system),
n a factor apparently necessary for the formation of a prothrombin-converting substance in blood and tissue extracts–i.e., intrinsic and extrinsic prothrombin activators. A deficiency results in parahemophilia (hypoproaccelerinemia).
factor VI,
n term formerly used to indicate an intermediate product in the formation of thromboplastin and also used synonymously with accelerin and activated factor V. It has no designation at present.
factor VII (stable factor, serum prothrombin conversion accelerator SPCA], proconvertin, autoprothrombin I, cofactor V, component B of prothrombin,
cothromboplastin, kappa factor, precusor of serum prothrombin conversion accelerator [pro-SPCA], prothrombin conversion factor, prothrombin converting factor, prothrombin conversion accelerator II, proconvertinconvertin system, prothrombinogen, serozyme, stable factor),
n a factor that accelerates the conversion of prothrombin to thrombin in the presence of factors III, IV, and V; a serum factor necessary for the formation of extrinsic prothrombin activator.
factor VII deficiency,
n a deficiency associated with a lack of vitamin K. A deficiency may be congenital, or it may be acquired in liver disease, or from prothrombinopenic agents used in anticoagulation therapy; it results in a prolonged (quantitative) one-stage prothrombin time test.
factor VIII (antihemophilic factor [AHF], antihemophilic globulin, antihemophilic globulin A, antihemophilic factor A, plasma thromboplastin factor [PTF], plasmokinin, platelet cofactor I, prothrombokinase, thrombocatalysin, thrombocytolysin, thrombokatilysin, thromboplastic plasma component [TPC], thromboplastinogen),
n a factor essential for the formation of blood thromboplastin. A deficiency results in classic hemophilia (hemophilia A); the clotting time is prolonged, and thromboplastin and prothrombin conversion is diminished.
factor IX (Christmas factor, plasma thromboplastin component [PTC], antihemophilic factor B, antihemophilic globulin B, autoprothrombin II, beta prothromboplastin, plasma factor X, plasma thromboplastin factor B PTF-B], platelet cofactor II),
n a factor that is active in the formation of intrinsic blood thromboplastin. A deficiency results in Christmas disease (hemophilia B), which is caused by a decrease in the amount of thromboplastin formed.
factor X (Stuart-Prower factor, Stuart factor, Prower factor),
n a factor influencing the yield of intrinsic (plasma) thromboplastin. A deficiency results in a prolonged one-stage prothrombin time. Brain tissue or Russell's viper venom are used to test for thromboplastin deficiency.
factor XI (plasma thromboplastin antecedent [PTA], antihemophilic factor C, PTA factor, plasma thromboplastin factor C [PTF-C]),
n a factor related to intrinsic (plasma) thromboplastin activation, which occurs when blood is exposed to a foreign surface.
factor XI deficiency,
n a deficiency caused by an autosomal recessive gene resulting in a hemorrhagic tendency. See also hemophilia C.
factor XII (Hageman factor, antihemophilic factor D, clot-promoting factor, fifth plasma thromboplastin precursor, glass factor),
n a factor the absence of which results in a long clotting time and abnormal prothrombin consumption and thromboplastin generation tests when tests are carried out in glass tubes. No abnormal bleeding tendency occurs with a deficiency of the factor.
factor XIII,
n a coagulation factor present in normal plasma that acts with calcium to produce an insoluble fibrin clot. Also called
fibrinase or
fibrin stabilizing factor.
factor XIII deficiency,
n a deficiency caused by a deficiency of vitamin E.
factor, acceleration,
n See factor V.
factor, antihemophilic (AHF),
n See factor VIII.
factor, antihemophilic A,
n See factor VIII.
factor, antihemophilic B,
n See factor IX.
factor, antihemophilic C,
n See factor XI.
factor, antihemophilic D,
n See factor XII.
factor, antipernicious,
n See vitamin B12.
factor, C (contact factor, contact activation product, third thromboplastic factor),
n a coagulation accelerator product formed by the interaction of active factor XII and factor XI.
factor, Castle's intrinsic (intrinsic factor),
n.pr a factor produced by the gastric mucosa and possibly the duodenal mucosa, and considered to be responsible for the absorption of vitamin B12. See also anemia, pernicious.
factor, Christmas,
n See factor IX.
factor, clot-promoting,
n See factor XII.
factor, clotting,
n the “trace” proteins (excluding calcium) present in normal blood in such small amounts (except fibrinogen) that their presence is usually established by deductive reasoning and by genetic and biochemical characteristics. They are associated with thromboplastic activity and the conversion of prothrombin to thrombin.
factor, contact,
n See factor C.
factor, environmental,
n the local conditions that modify tissue response (e.g., narrow interdental spaces, saddle areas, attachment of frenula, oblique ridges).
factor, erythrocyte-maturation (EMF),
factor, etiologic,
n the element or influence that can be assigned as the cause or reason for a disease or lesion.
factor, extrinsic,
factor, familial,
n a characteristic derived through heredity.
factor, glass,
n See factor XII.
factor, glucocorticoid,
factor, Hageman,
n See factor XII.
factor, Hr,
n blood factors that are reciprocally related to the Rh factors. They are present in agglutinogens when the corresponding Rh factor is absent from the gene.
factor, hyperglycemic,
n See glucagon.
factor, hyperglycemic-glycogenolytic,
n See glucagon.
factor, intrinsic,
n See factor, Castle's intrinsic.
factor, kappa,
n See factor VII.
factor, labile,
n See factor V.
factor, local,
n the limited factors that include dental plaque, bacterial toxins and irritants, calculus, food impaction, and other surface and locally placed irritants that are capable of injuring the periodontium.
factor, pellagra-preventive,
factor, plasma prothrombin conversion (PPCF),
n See factor V.
factor, plasma thromboplastin (PTF),
n the substances with thromboplastic activity contributed by the plasma. Included are the antihemophilic factor, Christmas factor, plasma thromboplastin antecedent, and Hageman factor. See also factor VIII.
factor, plasma thromboplastin, A (PTF-A),
n See factor VIII.
factor, plasma thromboplastin, B (PTF-B),
n See factor IX.
factor, plasma thromboplastin, C (PTF-C),
n See factor XI.
factor, plasma thromboplastin, D (PTF-D),
n this factor is considered by some to be a fourth plasma substance with thromboplastic activity; not well characterized.
factor, plasma, X,
n See factor IX.
factor, platelet,
n a substance on or in the surface of blood platelet necessary for coagulation in the absence of extravascular thromboplastic substances.
factor, platelet, 1,
n either factor V or a factor with factor V activity; absorbed on platelets and accelerates conversion of prothrombin to thrombin.
factor, platelet, 2,
n a substance that accelerates the conversion of fibrinogen to fibrin.
factor, platelet, 3,
n a substance associated with thromboplastin generation activity.
factor, platelet, 4,
n an antiheparin factor.
factor, prothrombin conversion,
n See factor VII.
factor, prothrombin-converting,
n See factor VII.
factor, Prower,
n.pr See factor X.
factor, psychosomatic,
n the psychic, mental, or emotional factors that play a role in determining the initiation, course, and extent of a physical process, either directly or indirectly. Psychosomatic factors have been implicated in bruxism, clenching, and other oral habits.
factor, PTA (plasma thromboplastin antecedent factor),
n See factor XI.
factor, reparative,
n the ability of the tissues to heal or regenerate when they have been subjected to injury or disease.
factor, Rh,
n the agglutinogens of red blood cells responsible for isoimmune reactions such as occur in erythroblastosis fetalis and incompatible blood transfusions.
factor, spreading,
n an enzyme that increases the permeability of ground substance.
factor, stable,
n See factor VII.
factor, Stuart,
n.pr See factor X.
factor, Stuart-Prower,
n.pr See factor X.
factor, third thromboplastic,
n See factor C.

factor

an agent or element that contributes to the production of a result. In epidemiology and statistics called also a variable because the factor may have a number of values. In an experiment a factor is a type of treatment and in the experiment the factor will be represented in different groups by different values. Such a factor may originate spontaneously or be introduced by an investigator.

factor analysis
a statistical method for analyzing the correlations between several variables.
antihemorrhagic factor
vitamin K.
antinuclear factor (ANF)
antinuclear antibody.
antirachitic factor
vitamin D.
factor B
a complement component (C3 proactivator) that participates in the alternate complement pathway.
C3 nephritic factor
a gamma globulin that is not an immunoglobulin, which is found in the plasma of certain individuals with membranoproliferative glomerulonephritis associated with hypocomplementemia; it initiates the alternate complement pathway.
citrovorum factor
folinic acid.
clotting f's, coagulation f's
factors essential to normal blood clotting, whose absence, diminution or excess may lead to abnormality of the clotting mechanism. See also clotting factors.
factor D
a factor that, when activated, serves as a serine esterase in the alternate complement pathway.
extrinsic factor
a hematopoietic vitamin that combines with intrinsic factor for absorption from the intestine and is needed for erythrocyte maturation; called also cyanocobalamin and vitamin B12.
F factor, fertility factor
the plasmid that determines the mating type of conjugating bacteria, being present in the donor (male) bacterium and absent in the recipient (female).
f's I to XIII
see clotting factors and names of individual factors.
factor VIII activity
a test for hemophilia A; activity is measured in biologic assays using factor VIII-deficient plasma as the substrate.
factor VIII-related antigen
von Willebrand antigen.
factor IX deficiency
see plasma thromboplastin component (PTC).
factor IX complex
a sterile, freeze-dried powder containing coagulation factors II, VII, IX and X.
factor X deficiency
see stuart factor.
factor XI deficiency
see plasma thromboplastin antecedent (PTA).
factor XII deficiency
fibrin stabilizing factor
factor XIII, one of the blood clotting factors that converts soluble fibrin monomer to insoluble, stable fibrin polymer.
intrinsic factor
a glycoprotein secreted by the parietal cells of the gastric glands, necessary for the absorption of vitamin B12 (cyanocobalamin, extrinsic factor). Its absence in humans results in pernicious anemia. Porcine stomach is a very rich source.
LE factor
an immunoglobulin (a 7S antibody) that reacts with leukocyte nuclei, found in the serum in systemic lupus erythematosus.
factor loading
a relationship between observable manifestations (or variables) and the underlying factors affecting the variables.
lymph node permeability factor (LNPF)
a substance from normal lymph nodes which produces vascular permeability.
lymphocyte transforming factor (LTF)
a lymphokine causing transformation and clonal expansion of lymphocytes.
osteoclast activating factor
substance produced by lymphocytes which facilitates bone resorption.
platelet f's
factors important in hemostasis that are contained in or attached to the platelets. See also platelet factors.
platelet-activating factor (PAF)
an immunologically produced substance which leads to clumping and degranulation of blood platelets.
R factor, resistance factor
a bacterial plasmid (R plasmid) which carries genes for antimicrobial resistance; it can be transmitted to other bacterial cells by conjugation, as well as to daughter cells.
release factor
a protein that binds directly to any stop codon that reaches the A site on the ribosome.
releasing f's
factors elaborated in one structure (as in the hypothalamus) that effect the release of hormones from another structure (as from the anterior pituitary gland), including corticotropin releasing factor, melanocyte-stimulating hormone releasing factor and prolactin releasing factor. Applied to substances of unknown chemical structure, while substances of established chemical identity are called releasing hormones.
transfer factor (TF)
a factor released from sensitized lymphocytes that has the capacity to transfer delayed hypersensitivity to a normal (nonsensitized) animal. See also transfer factor.

Patient discussion about factor

Q. What Are the Risk Factors for Developing Stroke? My father had a stroke recently, at the age of 73. What are the risk factors for developing this?

A. Primary risk factors include:

1) smoking
2) excessive alcohol intake
3) uncontrolled high blood pressure
4) high cholesterol
5) overweight/unhealthy diet
6) illegal drugs/abuse of Rx drugs
7) known or unknown heart problems
8) diabetes
9) known or unknown vascular brain defects - aneurysm, etc.
10)family history of stroke

Q. Regarding risk-factor assessment? Hello, I am……….., I heard ACSM has recently issued a new edition of its exercise guidelines. Were any changes made regarding risk-factor assessment?

A. Are you fitness professional? I understand that you are very much interested in food guidelines. It can be difficult to keep up with the latest guidelines and standards. This is particularly true this year, which has seen new USDA Food Guidelines in January, a revised Food Pyramid in May and, most recently, the release of the 7th edition of ACSM’s Guidelines for Exercise Testing and Prescription. The good news is that the ACSM risk factors have been minimally revised. For your reference, here is a summary of what has and has not changed for the 2006 edition.

Q. Is obesity a risk factor for Dementia?

A. The answer is YES. In fact, many of the risk factors for heart disease, such as high blood pressure, blood glucose levels, insulin resistance, and overweight, are also risk factors for dementia, in addition to genetic predisposition for the disease.

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