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anaphoresis

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(an″ă-fŏ-rē′sĭs) [ana- + -phoresis] The flow of electrically positive particles toward the anode (positive pole) in electrophoresis.

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anaphylactic

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(an″ă-fĭ-lak′tik) Pert. to anaphylaxis. anaphylactically (ti-k(ă-)lē), adv.

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anaphylactic reaction

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Anaphylaxis.

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anaphylactogenic

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(an″ă-fĭ-lak″tŏ-jen′ik) [anaphylactic + -genic] Producing anaphylaxis. anaphylactogenic, n.

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anaphylactoid reaction

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(an″ă-fĭ-lak′ ′toyd″) [anaphylact(ic) + -oid] A reaction that resembles anaphylaxis, e.g., by hives, laryngeal edema, or shock, but does not involve IgE antibodies or allergens and therefore is has no allergic basis.

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ETIOLOGY: This relatively uncommon type of reaction can be caused by exercise; as the result of the release of histamine when body temperature rises; by elevated endorphin levels; by ionic compounds such as contrast media that contain radiographic iodine or polymyxin B antibiotic; by solutions containing polysaccharides such as dextran; by morphine, codeine, or meperidine; and by NSAIDs. The term should not be used as a synonym for mild anaphylaxis produced by IgE-allergen reactions.

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SYMPTOMS: Anaphylactoid reactions produce hives and itching identical to those of anaphylaxis. Very rarely, severe anaphylaxis or anaphylactic shock occurs. Anaphylactoid reactions are treated with the same drugs used to treat anaphylaxis.

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anaphylatoxin

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(an″ă-fil-ă-tok′sĭn) [anaphyla(xis) + toxin] Complement components C3a, C4a, and C5a, which cause degranulation of mast cells and release of chemical mediators that promote the smooth muscle spasm, increased vascular permeability, increased mucus secretion, and attraction of neutrophils and eosinophils associated with systemic anaphylaxis.

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anaphylaxis

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(an″ă-fĭ-lak′sĭs) [ana- + (pro)phylaxis] A sudden, severe allergic reaction between an allergenic antigen and immunoglobulin E (IgE) bound to mast cells, which stimulates the sudden release of immunological mediators locally or throughout the body. The first symptoms occur within minutes, and a recurrence may follow hours later (late-stage response). Anaphylaxis can only occur in someone previously sensitized to an allergen because the initial exposure causes immunoglobulin E (IgE) to bind to mast cells. Anaphylaxis may be local or systemic. Local anaphylactic reactions include hay fever, hives, and allergic gastroenteritis. Systemic anaphylaxis produces peripheral vasodilation, bronchospasm, and laryngeal edema and can be life-threatening. anaphylactic (an″ă-fĭ-lak′tik), adj.

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ETIOLOGY: IgE antibodies react when the allergen is introduced a second time. The mast cells release packets containing chemical mediators (degranulators) that attract neutrophils and eosinophils and stimulate urticaria (hives) and vasodilation, increased vascular permeability, and smooth muscle spasm, esp. in the bronchi and gastrointestinal tract. Chemical anaphylactic mediators include histamine, proteases, chemotactic factors, leukotrienes, prostaglandin D, and cytokines, e.g., TNF- α and interleukins 1, 3, 4, 5, and 6. The most common agents triggering anaphylaxis are food, drugs, and insect stings. Local anaphylactic reactions are also commonly triggered by pollens, e.g., hay fever, allergic rhinitis, ...

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