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(im″yŭ-nō-tok′sin, i-mū″nō-tok′sin) [immuno- + toxin] Any medication or poison chemically linked to antibodies, used to target and destroy cells with specific receptors, esp. cancerous cells.


(ĭm-păk′tĕd) [L. impactus, pressed on] Pressed firmly together so as to be immovable. This term may be applied to a fracture in which the ends of the bones are wedged together, a tooth so placed in the jaw bone that eruption is impossible, a fetus wedged in the birth canal, cerumen, calculi, or accumulation of feces in the rectum.


(im-pak′shŏn) [L. impactio, stem impaction-, concussion, impact] A condition of being tightly wedged into a part, as when the eruption of a tooth is blocked by other teeth or when an organ is overloaded, as the bowels by feces.

fecal i. Constipation caused by a firm mass of feces in the distal colon or rectum. The size or firmness of the mass prevents its passage.

 ETIOLOGY: Fecal impaction is relatively common in older adults, esp. in immobilized residents of nursing homes, and in children with encopresis. It may also result from painful anal conditions that inhibit the patient's desire to defecate; drugs such as narcotics, calcium-channel blockers, retained barium, or anticholinergics that retard bowel movements; neurological diseases such as spinal cord injury; complications of intestinal or obstetrical surgery; dehydration; rectoceles, colon cancers, or other pathological lesions; and functional (psychogenic) disorders.

 SYMPTOMS: Abdominal colic and a sensation of fullness, anorexia, and rectal pain are common.

PATIENT CARE: Impaction of stool may be prevented by following a high-fiber, fluid-rich diet; getting regular exercise; limiting intake of constipating drugs; routinely using stool softeners or laxatives; and learning biofeedback and habit-training.

 A trial of laxatives or enemas may relieve the obstructing feces. If this is unsuccessful, manual extraction is indicated. This may require local anesthesia. The impaction is fragmented by using a scissoring action of the fingers. After the impaction is fragmented, use of mild laxatives, such as mineral oil instilled into the rectum, provides lubrication and assists in passage of the fragments. Surgery is rarely required.

food i. 1. The forcing of food into the interproximal spaces of teeth by chewing (vertical impaction) or by tongue and cheek pressure (horizontal impaction). 2. The obstruction of the upper gastrointestinal (GI) tract by food, or of the lower GI tract by feces.


(im-pard′) [Fr. empeirer, to make worse] Not functioning or behaving appropriately because of damage, illness, or weakness. In the health care professions, it refers to a physician, nurse, or other professional too ill or incapacitated to carry out his or her professional duties. Neurological diseases, e.g., strokes or ...

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