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Definition
 
enEnglish
Activation Analysis definition: A method of chemical analysis based on the detection of characteristic radionuclides following a nuclear bombardment. It is also known as radioactivity analysis. (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)
activation analysis definition: chemical analytic method based on the detection of characteristic radionuclides following a nuclear bombardment.
Complement Activation definition: The sequential activation of serum COMPLEMENT PROTEINS to create the COMPLEMENT MEMBRANE ATTACK COMPLEX. Factors initiating complement activation include ANTIGEN-ANTIBODY COMPLEXES, microbial ANTIGENS, or cell surface POLYSACCHARIDES.
complement activation definition: Any process involved in the activation of any of the steps of the complement cascade, which allows for the direct killing of microbes, the disposal of immune complexes, and the regulation of other immune processes; the initial steps of complement activation involve one of three pathways, the classical pathway, the alternative pathway, and the lectin pathway, all of which lead to the terminal complement pathway. [GO_REF:0000022, GOC:add, GOC:mtg_15nov05, ISBN:0781735149 "Fundamental Immunology"]
complement pathway regulation definition: factors which act in the complement sequence to activate, modulate or prevent the progression of the reaction.
Complement Activation definition: The complement system consists of more than 30 proteins engaged in host defense. It provides both an independent immune system capable of attacking microbes as well as other foreign material and an adjunct to the antibody system. Once activated, the complement system fires in a cascade-like fashion in which one component activates the next. Both swift and powerful, millions of complement components can deposit on an invading microbe within only a few minutes. Such a potent system requires strict regulation to avoid host injury. Membrane cofactor protein (MCP) is one critical regulator aimed at controlling inadvertent complement activation on host cells and nearly every cell examined expresses MCP on its cell membrane.
Enzyme Activation definition: Conversion of an inactive form of an enzyme to one possessing metabolic activity. It includes 1, activation by ions (activators); 2, activation by cofactors (coenzymes); and 3, conversion of an enzyme precursor (proenzyme or zymogen) to an active enzyme.
Lymphocyte Activation definition: Morphologic alteration of small B LYMPHOCYTES or T LYMPHOCYTES in culture into large blast-like cells able to synthesize DNA and RNA and to divide mitotically. It is induced by INTERLEUKINS; MITOGENS such as PHYTOHEMAGGLUTININS, and by specific antigens. It may also occur in vivo as in GRAFT REJECTION.
lymphocyte activation definition: A change in morphology and behavior of a lymphocyte resulting from exposure to a specific antigen, mitogen, cytokine, chemokine, cellular ligand, or soluble factor. [GOC:mgi_curators, ISBN:0781735140]
Lymphocyte Activation definition: Lymphocyte Activation involves stimulation of the production and activity of lymphocytes. Formed in lymphoid tissue, lymphocytes are white blood cells that can generally be classified as either T- or B-cells. T-lymphocytes provide cell-mediated immunity, while B-lymphocytes produce antibodies that provide humoral immunity. Stimulation increases the immune response to invading substances.
Macrophage Activation definition: The process of altering the morphology and functional activity of macrophages so that they become avidly phagocytic. It is initiated by lymphokines, such as the macrophage activation factor (MAF) and the macrophage migration-inhibitory factor (MMIF), immune complexes, C3b, and various peptides, polysaccharides, and immunologic adjuvants.
macrophage activation definition: A change in morphology and behavior of a macrophage resulting from exposure to a cytokine, chemokine, cellular ligand, or soluble factor. [GOC:mgi_curators, ISBN:0781735149 "Fundamental Immunology", PMID:14506301]
Platelet Activation definition: A series of progressive, overlapping events, triggered by exposure of the PLATELETS to subendothelial tissue. These events include shape change, adhesiveness, aggregation, and release reactions. When carried through to completion, these events lead to the formation of a stable hemostatic plug.
platelet activation definition: process by which platelets change shape, aggregate, adhere to vascular wall, and secrete cytokines during clotting; induced by a variety of agonists including thrombin, ADP, PAF, and epinephrine via a G protein/IP3 coupled receptor system.
platelet activation definition: A series of progressive, overlapping events triggered by exposure of the platelets to subendothelial tissue. These events include shape change, adhesiveness, aggregation, and release reactions. When carried through to completion, these events lead to the formation of a stable hemostatic plug. [http://www.graylab.ac.uk/omd/]
Platelet Activation definition: Platelet Activation involves initiation of a set of stimulated platelet activities involved in aggregation of platelets and fibrin during blood coagulation. Containing mitochondria and granules of active enzymes, blood platelets are non-nucleated irregular disk-shaped cytoplasmic fragments of megakaryocytes and shed from the marrow sinus into the peripheral blood.
Virus Activation definition: The mechanism by which latent viruses, such as genetically transmitted tumor viruses (PROVIRUSES) or PROPHAGES of lysogenic bacteria, are induced to replicate and then released as infectious viruses. It may be effected by various endogenous and exogenous stimuli, including B-cell LIPOPOLYSACCHARIDES, glucocorticoid hormones, halogenated pyrimidines, IONIZING RADIATION, ultraviolet light, and superinfecting viruses.
Transcriptional Activation definition: Processes that stimulate the GENETIC TRANSCRIPTION of a gene or set of genes.
Transcriptional Activation definition: The process by which an unexpressed gene is activated to serve as a transcription template for synthesis of RNA.
Neutrophil Activation definition: The process in which the neutrophil is stimulated by diverse substances, resulting in degranulation and/or generation of reactive oxygen products, and culminating in the destruction of invading pathogens. The stimulatory substances, including opsonized particles, immune complexes, and chemotactic factors, bind to specific cell-surface receptors on the neutrophil.
neutrophil activation definition: The change in morphology and behavior of a neutrophil resulting from exposure to a cytokine, chemokine, cellular ligand, or soluble factor. [GOC:mgi_curators, ISBN:0781735149 "Fundamental Immunology"]
Neutrophil Activation definition: Neutrophil Activation involves cell interaction and cell signaling mechanisms of that recognize or respond to the presence of foreign antigen and that stimulate phagocytosis, degranulation, or generation of reactive oxygen products by neutrophils to destroy invading pathogens or to induce acute inflammatory reactions.
activation product definition: initiation of the intrinsic pathway of coagulation through interaction of coagulation factor XII with various electronegative surfaces, such as collagen fibers, skin, or sebum in vivo, or particulate silicates in vitro.
basophil activation definition: The change in morphology and behavior of a basophil resulting from exposure to a cytokine, chemokine, soluble factor, or to (at least in mammals) an antigen which the basophil has specifically bound via IgE bound to Fc-epsilonRI receptors. [GOC:mgi_curators, ISBN:0781735149 "Fundamental Immunology"]
activation of anaphase-promoting complex definition: Any process that initiates the ubiquitin ligase activity of the anaphase-promoting complex. [GOC:dph, GOC:mah, GOC:tb, PMID:10871297]
astrocyte activation definition: A change in morphology and behavior of an astrocyte resulting from exposure to a cytokine, chemokine, cellular ligand, or soluble factor. [GOC:mgi_curators, PMID:10526094, PMID:10695728, PMID:12529254, PMID:12580336, PMID:9585813]
induction of apoptosis definition: A process that directly activates any of the steps required for cell death by apoptosis. [GOC:go_curators]
commitment to apoptosis definition: OBSOLETE (was not defined before being made obsolete). [GOC:go_curators]
Induction of Apoptosis definition: Mechanisms involved in Induction of Apoptosis initiate biochemical processes, often enzymatic cascades, that promote programmed cell death.
activation of Hog1 definition: OBSOLETE (was not defined before being made obsolete). [GOC:ai]
activation of Pbs2 definition: OBSOLETE (was not defined before being made obsolete). [GOC:ai]
Clinical Study Activation Date definition: The date on which a trial was opened to accrual.
Antibody Activation definition: Antibody Activation involves induction of the function of a class of cell-surface or secreted B lymphocyte proteins that non-covalently interact through intermolecular physical forces of attraction and spatial complementarity selectively and specifically with foreign substances (antigens), typically as part of an immune response. Activation mechanisms include decreased degradation or increased production and binding to antigen.
activation of membrane attack complex definition: The activation of the membrane attack complex components of the complement cascade which can result in death of a target cell through cytolysis. [GOC:add, ISBN:0781735149 "Fundamental Immunology"]
positive regulation of CREB transcription factor activity definition: Any process that activates or increases the frequency, rate or extent of activity of the transcription factor CREB. [GOC:dph, GOC:ecd, GOC:tb]
Activation definition: To cause something to start or to stimulate activity.
activation definition: Activation.
 
 
deGerman
Aktivierungsenergie definition: [1] Chemie: die Energie, die man zwei Reaktionspartnern zuführen muss, damit eine Reaktion eintritt
 
frFrench
radioactivation definition: Processus par lequel un nucléide stable est transformé en un nucléide radioactif.
activation definition: Action de rendre actif.