Rejection

Rejection
In transplantation biology, the refusal by the body to accept transplanted cells, tissues or organs. For example, a kidney transplanted may be rejected.
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1. The immunologic response to incompatibility in a transplanted organ. 2. A refusal to accept, recognize, or grant; a denial. 3. Elimination of small ultrasonic echoes from display. [L. rejectio, a throwing back]
- accelerated r. a transplant r. manifested in less than 3 days.
- acute r. SYN: acute cellular r..
- acute cellular r. graft r. that usually begins within 10 days after a graft has been transplanted into a genetically dissimilar host. Lesions at the site of the graft characteristically are infiltrated with large numbers of lymphocytes and macrophages that cause tissue damage. See primary r.. SYN: acute r..
- allograft r. (al′lo-graft) the r. of tissue transplanted between two genetically different individuals of the same species. R. is caused by T lymphocytes responding to the foreign major histocompatibility complex of the graft.
- chronic r. a transplant r. occurring gradually, sometimes months later.
- chronic allograft r. immunologically mediated damage to the allograft, typically occurring months or years after transplantation.
- first-set r. allograft transplantation between two organisms not previously sensitized to the graft tissue. Necrosis of the graft usually begins within 10 days of transplantation.
- hyperacute r. 1. a r. that usually develops immediately after the implantation of a vascular graft; may be caused by preformed, cytotoxic antibodies to the graft; 2. a form of antibody-mediated, usually irreversible damage to a transplanted organ, particularly the kidney, manifested predominantly by diffuse thrombotic lesions, usually confined to the organ itself and only rarely disseminated.
- parental r. 1. withholding of affection from or denial of attention to one's child; 2. child's withholding of affection from its parent.
- primary r. a r. occurring more than 7 days after transplantation, mainly from a cellular immune response.
- second set r. an accelerated r. of a transplant that occurs when an individual has been previously sensitized to the graft.

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re·jec·tion ri-'jek-shən n
1) the action of rejecting or the state of being rejected <feelings of \rejection> <\rejection of the atypical child by the...group (G. S. Speer)>
2) an immune response in which foreign tissue (as of a skin graft or transplanted organ) is attacked by immune system components (as antibodies, T cells, and macrophages) of the recipient organism

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n.
(in transplantation) the destruction by immune mechanisms of a tissue grafted from another individual. Antibodies, complement, clotting factors, and platelets are involved in the failure of the graft to survive. allograft rejection is a vigorous response that can be modified by drugs (such as ciclosporin and corticosteroids) and antibodies against T-cells; xenograft rejection is an acute response that is at present beyond therapeutic control.

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re·jec·tion (re-jekґshən) an immune response against grafted tissue that may result in failure of the graft to survive; called also graft r.

Medical dictionary. 2011.

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  • rejection — 1550s, from Fr. réjection (16c.) or directly from L. rejectionem, noun of action from reicere (see REJECT (Cf. reject)). In 19c., it also could mean “excrement.” Medical transplant sense is from 1954. In the psychological sense, relating to… …   Etymology dictionary

  • Rejection — Re*jec tion (r? j?k sh?n), n. [L. rejectio: cf. F. r[ e]jection.] Act of rejecting, or state of being rejected. [1913 Webster] …   The Collaborative International Dictionary of English

  • rejection — [n] denial, refusal bounce, brushoff*, cold shoulder*, disallowance, dismissal, elimination, exclusion, hard time*, kick in teeth*, nix*, no dice*, no go*, nothing doing*, no way*, pass*, rebuff, renunciation, repudiation, slap in the face*,… …   New thesaurus

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  • réjection — (ré jè ksion) s. f. Action de rejeter hors de soi. •   Les chenilles doivent rejeter la membrane fine.... cette réjection...., BONNET Obs. 5e insectes..    Fig. •   Cette réjection des sacrements, BAYLE art. Pellisson, note j.. •   Sa communion… …   Dictionnaire de la Langue Française d'Émile Littré

  • rejection */*/ — UK [rɪˈdʒekʃ(ə)n] / US noun Word forms rejection : singular rejection plural rejections 1) [countable/uncountable] a refusal to accept, approve, or support something Their rejection of the peace plan raises the threat of a more general war.… …   English dictionary

  • rejection — Refusal by a bank to grant credit, usually because of the applicants financial history, or refusal to accept a security presented to complete a trade, usually because of a lack of proper endorsements or violation of rules of a firm. Bloomberg… …   Financial and business terms

  • Rejection — (Roget s Thesaurus) < N PARAG:Rejection >N GRP: N 1 Sgm: N 1 rejection rejection repudiation exclusion Sgm: N 1 refusal refusal &c. 764 Sgm: N 1 declination declination PARAG:Rejection >V GRP: V 1 Sgm: V 1 r …   English dictionary for students

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