an agent or element that contributes to the production of a result.
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.
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
, 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]).
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.
component that participates in the alternative complement pathway.
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.
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
a factor that when activated serves as a serine
esterase in the alternative complement
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
F factor (fertility factor) F plasmid.
growth factor any substance that promotes skeletal or somatic growth; usually a mineral, hormone, or vitamin.
system regulatory protein that inhibits the alternative pathway of complement activation.
(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.
(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
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.
a glycoprotein secreted by the parietal cells of the gastric glands, necessary for the absorption of cyanocobalamin
). 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 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.
migration inhibition factor
(migration inhibitory factor
) a lymphokine
that inhibits macrophage
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.
(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.
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.
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.
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.
(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
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
factor /fac·tor/ (fak´ter) an agent or element that contributes to the production of a result.
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 A
coagulation f. VIII
antihemophilic factor B
coagulation f. IX
antihemophilic factor C
coagulation f. XI
(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.
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.
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 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 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
(FSF) coagulation f. XIII
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.
(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.
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.
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.
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.
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-Prower factor
coagulation f. X
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
) is produced by macrophages, eosinophils, and NK cells. Tumor necrosis factor β,
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 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.
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
, 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.
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.
a statistical method for analyzing the correlations between several variables.
antinuclear factor (ANF)
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.
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
a factor that, when activated, serves as a serine esterase in the alternate complement pathway.
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
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.
fibrin stabilizing factor
factor XIII, one of the blood clotting factors that converts soluble fibrin monomer to insoluble, stable fibrin polymer.
a glycoprotein secreted by the parietal cells of the gastric glands, necessary for the absorption of vitamin
(cyanocobalamin, extrinsic factor). Its absence in humans results in pernicious anemia. Porcine stomach is a very rich source.
an immunoglobulin (a 7S antibody) that reacts with leukocyte nuclei, found in the serum in systemic lupus erythematosus.
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.
factors important in hemostasis that are contained in or attached to the platelets. See also platelet
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.
a protein that binds directly to any stop codon
that reaches the A site on the ribosome.
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:
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
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.More discussions about factor