| passive haemagglutination | A kind of passive agglutination in which erythrocytes, usually modified by mild treatment with tannic acid or other chemicals, are used to adsorb soluble antigen onto their surface, and which then agglutinate in the presence of antiserum specific for the adsorbed antigen. Synonym: indirect haemagglutination test. (05 Mar 2000) |
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| passive hyperaemia | Hyperaemia due to an obstruction in the flow of blood from the affected part, the venous radicles becoming distended. Synonym: venous hyperaemia. (05 Mar 2000) |
| passive immunity | <immunology> Immunity acquired by the transfer from another animal of antibody or sensitised lymphocytes. Passive transfer of antibody from mother to offspring is important for immune defense during the perinatal period. (18 Nov 1997) |
| passive immunization | The production of passive immunity. (05 Mar 2000) |
| passive immunotherapy | <immunology> A process in which individuals with advanced disease (who have low levels of HIV antibody production) are infused with plasma rich in HIV antibodies or an immunoglobulin concentrate (HIV Ig) from such plasma. The plasma is obtained from asymptomatic HIV-positive individuals with high levels of HIV antibodies. (09 Oct 1997) |
| passive incontinence | Dribbling of urine by reason of inability of the bladder to empty itself and of consequent overdistention. See: overflow incontinence. (05 Mar 2000) |
| passive learning | Learning without a direct attempt. Synonym: passive learning. (05 Mar 2000) |
| passive medium | A medium that produces no change in the specimens placed in it. (05 Mar 2000) |
| passive movement | Movement imparted to an organism or any of its parts by external agency; movement of any joint effected by the hand of another person, or by mechanical means, without participation of the subject himself. (05 Mar 2000) |
| passive prophylaxis | Use of an antiserum from another person or animal to provide temporary (a week to 10 days) protection against a specific infectious or toxic agent. (05 Mar 2000) |
| passive transference | The passage of an immunity or allergic susceptibility by the injection of serum of an animal or individual who has acquired an active immunity to the disease. (05 Mar 2000) |
| passive transport | <biochemistry, physiology> The movement of a substance, usually across a plasma membrane, by a mechanism that does not require metabolic energy. See: active transport, transport protein, facilitated diffusion, ion channels. (18 Nov 1997) |
| passive tremor | A coarse, rhythmic tremor, 3-5 Hz frequency, usually confined to hands and forearms, that appears when the limbs are relaxed, and disappears with active limb movements; characteristic of Parkinson disease. Synonym: passive tremor. (05 Mar 2000) |
| passive vasoconstriction | Reduced caliber of a vessel caused by decreased intraluminal pressure. (05 Mar 2000) |
| passive vasodilation | Vasodilation related to increased pressure in lumen of a vessel. (05 Mar 2000) |