释义 |
acute phase reaction a·cute phase re·ac·tionto the changes in synthesis of certain proteins within the serum during an inflammatory response; this response provides rapid protection for the host against microorganisms through nonspecific defense mechanisms. Synonym(s): acute phase responseAcute Phase Response A constellation of nonspecific host responses to cytokines* released in response to tissue injury, infection, inflammation and rarely malignancy—e.g., Hodgkin lymphoma, renal cell carcinoma—which causes functional liver changes—increased synthesis of acute phase proteins (endocrine system), abnormal glucose tolerance, increased gluconeogenesis, thyroid dysfunction, altered lipid metabolism (immune system), left shift leukocytosis, hypergammaglobulinaemia (metabolic system), decreased albumin synthesis, energy consumption, increased ceruloplasmin, reduced iron and zinc levels, and CNS (lethargy); the most measured molecule in the response is the highly nonspecific CRP, which may increase 10- to 1000-fold within hours from a normal level of 100 µg/L. *Biological response modifiers—e.g., IL-1alpha, IL-6, TNF-alpha, TGF-beta-1, and interferons; intercellular communication is mediated by either direct cell-to-cell contact, or by soluble signalling molecules including hormones, eicosanoids, neurotransmitters, and to cytokines, which may play the most central role in inducing the APR; other molecules involved in the APR include corticosteroids, insulin, thrombin, histamine, and others; screening tests for the APR include erythrocyte sedimentation rate, plasma viscosity, and zeta sedimentation ratio.a·cute phase re·ac·tion (ă-kyūt' fāz rē-ak'shŭn) Refers to the changes in synthesis on certain proteins within the serum during an inflammatory response; this response provides rapid protection for the host against microorganisms via nonspecific defense mechanisms. Synonym(s): acute phase response. acute phase reactionThe release of physiologically active proteins by the liver into the blood in response to interleukin-6 or other cytokines that participate in the destruction of pathogens and promote healing during inflammation. This results in fever, an increase in circulating neutrophils, and activation of the hypothalamus, pituitary gland, and adrenal glands. The acute phase response involves the production of plasma proteins as well as other metabolic, hematological, and neuroendocrine events. Cytokines, produced by white blood cells, esp. macrophages, stimulate the liver's production of acute phase proteins: interleukin-6, interleukin-1ß, tumor necrosis factor a, interferon-?, and transforming growth factor ß. These proteins, which increase or decrease in the blood by at least 25%, include C-reactive protein, complement, and coagulation factors; they enhance the immune response and tissue repair. Cytokines also stimulate systemic changes, producing diverse beneficial effects including fever, which enhances the immune response and stabilizes cell membranes; increased adrenal cortisol and catecholamine production, which helps maintain hemodynamic stability; thrombocytosis and leukocytosis; and increased gluconeogenesis and lipolysis, which provide nutrients for cells. There are also negative effects, however, including decreased production of erythropoietin, causing anemia; impaired growth; anorexia; lethargy; and, if prolonged, the loss of skeletal muscle and fat (cachexia). Synonym: acute phase response. See: cytokine; inflammation; interleukin-6; protein, acute phase |