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Medical Dictionary


regurgitate ( re-ger′ji-tat)
1. To flow backward. 2. To expel the contents of the stomach in small amounts, short of vomiting. [L. re-, back, + gurgito, pp. -atus, to flood, fr. gurges (gurgit-), a whirlpool]

regurgitation (re-ger′ji-ta′shun)
1. A backward flow, as of blood through an incompetent valve of the heart. 2. The return of gas or small amounts of food from the stomach. [L. regurgitatio (see regurgitate)] aortic r. reflux of blood through an incompetent aortic valve into the left ventricle during ventricular diastole. SYN: Corrigan disease. ischemic mitral r. a r. of the mitral valve caused by ischemic heart disease. mitral r. reflux of blood through an incompetent mitral valve. pulmonic r. incompetence of the pulmonic valve permitting retrograde flow. valvular r. a leaky state of one or more of the cardiac valves, the valve not closing tightly and blood therefore regurgitating through it. SYN: valvular incompetence, valvular insufficiency.

rehabilitation (re′ha-bil-i-ta′shun)
Restoration, following disease, illness, or injury, of the ability to function in a normal or near-normal manner. [L. rehabilitare, pp. -tatus, to make fit, fr. re- + habilitas, ability] mouth r. restoration of the form and function of the masticatory apparatus to as nearly a normal condition as possible.

rehearsal (re-her′sal)
A process associated with enhancing short-term and long-term memory wherein newly presented information, such as a name or a list of words, is repeated to oneself one or more times in order not to forget it.

Martin E., U.S. physician, 1887–1964. See R. method, R. stomach tube.

rehydration (re-hi-dra′shun)
The return of water to a system after its loss.

Friedrich P., German gynecologist and surgeon, 1858–1934. See R.-Pólya stomach procedure.

Karl B., German anatomist, 1811–1883. See R. cartilage, R. cochlear recess, R.-Meissl number.

Robert W., Scottish anatomist, 1851–1939. See R. base line.

Edward C. Jr., U.S. endocrinologist, 1908–1975. See R. syndrome.

Johann C., German physician, neurologist, and histologist, 1759–1813. See R. ansa, R. band, R. ribbon, R. triangle, limiting sulcus of R., circular sulcus of R., island of R..

reimplantation (re′im-plan-ta′shun)
SYN: replantation. extravesical r. SYN: detrusorrhaphy. ureteral r. SYN: ureteroneocystostomy.

reinfection (re-in-fek′shun)
A second infection by the same microorganism, after recovery from or during the course of a primary infection.

reinforcement (re-in-fors′ment)
1. An increase of force or strength; denoting specifically the increased sharpness of the patellar reflex when the patient at the same time closes the fist tightly or pulls against the flexed fingers or contracts some other set of muscles. SEE ALSO: Jendrassik maneuver. 2. In dentistry, a structural addition or inclusion used to give additional strength in function; e.g., bars in plastic denture base. 3. In conditioning, the totality of the process in which the conditioned stimulus is followed by presentation of the unconditioned stimulus, which itself elicits the response to be conditioned. SEE ALSO: reinforcer, schedules of r., under schedule, classical conditioning, operant conditioning. primary r. satisfaction of physiologic needs or drives, such as that supplied by food or sleep. secondary r. r. through something which, while it does not satisfy the need directly, has been associated with direct satisfaction of the need, such as the effect on behavior of a food or beer commercial on television.

reinforcer (re-in-fors′er)
In conditioning, a pleasant or satisfaction-yielding (positive r.) or painful or unsatisfying (negative r.), stimulus, object, or stimulus event that is obtained upon the performance of a desired or predetermined operant. SEE ALSO: reinforcement (3) . SYN: reward.

Friedrich B., German anatomist, 1862–1919. See R. crystalloids, under crystalloid.

reinnervation (re-in-ner-va′shun)
Restoration of nerve control of a paralyzed muscle or other effector organ by means of regrowth of nerve fibers, either spontaneously or after anastomosis.

reinoculation (re′i-nok-u-la′shun)
Reinfection by means of inoculation.

Adolf, German physician, 1862–1916. See R. test.

reintegration (re′in-te-gra′shun)
In the mental health professions, the return to well-adjusted functioning following disturbances due to mental illness.

reinversion (re-in-ver′shun)
The correction, spontaneous or operative, of an inversion, as of the uterus.

Heinrich Maria Wilhelm, German ophthalmologist, *1872. See R.-Bücklers corneal dystrophy. SEE ALSO: R.-Bücklers corneal dystrophy.

Franz D., German anatomist, 1773–1828. See R. muscles, under muscle.

Ernst, German anatomist, 1824–1878. See R. fiber, R. membrane.

Ralph M., U.S. psychologist, *1922. See Halstead-R. battery.

Hans, German bacteriologist, 1881–1969. See R. test, R. disease, R. syndrome, Fiessinger-Leroy-R. syndrome.

rejection (re-jek′shun)
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.

rejuvenescence (re-joo-ve-nes′ens)
A renewal of youth; return of a cell or tissue to a state in which it was in an earlier stage of existence. [L. re-, again, + juvenesco, to grow young, fr. juvenis, a youth]

relapse (re′laps)
Return of the manifestations of a disease after an interval of improvement. SYN: recurrence (2) . [L. re-labor, pp. -lapsus, to slide back]

relapsing (re-lap′sing)
Recurring; said of a disease or its manifestations that returns in a new attack after an interval of improvement.

relation (re-la′shun)
1. An association or connection between or among people or objects. SEE ALSO: relationship. 2. In dentistry, the mode of contact of teeth or the positional relationship of oral structures. [L. relatio, a bringing back] acquired centric r. centric jaw r.. acquired eccentric r. an eccentric r. that is assumed by habit in order to bring the teeth into occlusion. buccolingual r. the position of a space or tooth in r. to the tongue and the cheek. centric jaw r., centric r. 1. the most retruded physiologic r. of the mandible to the maxillae to and from which the individual can make lateral movements; it is a condition that can exist at various degrees of jaw separation, and it occurs around the terminal hinge axis; 2. the most posterior r. of the mandible to the maxillae at the established vertical r. SEE ALSO: eccentric r.. SYN: median retruded r., median r.. dynamic relations relative movements between two objects, e.g., the relationship of the mandible to the maxillae. eccentric r. any r. of the mandible to the maxillae other than centric r.. SYN: eccentric position. intermaxillary r. SYN: maxillomandibular r.. maxillomandibular r. any one of the many relations of the mandible to the maxillae, e.g., centric jaw r., eccentric r.. SYN: intermaxillary r.. median retruded r., median r. SYN: centric jaw r.. occluding r. the jaw r. at which the opposing teeth occlude. protrusive r. the r. of the mandible to the maxillae when the lower jaw is thrust forward. protrusive jaw r. a jaw r. resulting from a protrusion of the mandible. rest r. the postural r. of the mandible to the maxillae when the patient is resting comfortably in the upright position and the condyles are in a neutral unstrained position in the glenoid fossa. SYN: rest jaw r., unstrained jaw r.. rest jaw r. SYN: rest r.. ridge r. the positional r. of the mandibular ridge to the maxillary ridge. static r. relationship between two parts that are not in motion. unstrained jaw r. SYN: rest r..

relationship (re-la′shun-ship)
The state of being related, associated, or connected. dose-response r. r. in which a change in the amount, intensity, or duration of exposure is associated with a change in risk of a specified outcome. dual relationships relationships in which a health service provider is concurrently participating in two or more role categories with a patient; such dual relationships may be benign (as when both are members of the same social group) or exploitive (a sexual r.). Haldane r. a mathematical r. between the equilibrium constant of an enzyme-catalyzed reaction and all of that enzyme's kinetic parameters ( e.g., Vmax and Km's). hypnotic r. r. between hypnotist and the hypnotized. object r. in the behavioral sciences, the emotional bond between an individual and another person (or between two groups), as opposed to the individual's (or group's) interest in him or herself (itself). sadomasochistic r. a r. characterized by the complementary enjoyment of inflicting and suffering cruelty.

relax (re-laks′)
1. To loosen; to slacken. 2. To cause a movement of the bowels. [L. re-laxo, to loosen]

relaxant (re-lak′sant)
1. Relaxing; causing relaxation; reducing tension, especially muscular tension. 2. An agent that reduces muscular tension or produces skeletal muscle paralysis, usually referred to as a muscle r.. depolarizing r. an agent, e.g., succinylcholine, that induces depolarization of the motor endplate and so paralyzes skeletal muscle by a phase I block. muscle r. a drug with the capacity to reduce muscle tone; may be either a peripherally acting muscle r. such as curare and act to produce blockade at the neuromuscular junction (and thus useful in surgery), or act as a centrally acting muscle r. exerting its effects within the brain and spinal cord to diminish muscle tone (and thus useful in muscle spasm or spasticity). neuromuscular r. an agent, e.g., curare or succinylcholine, that produces relaxation of striated muscle by interruption of transmission of nervous impulses at the myoneural junction. nondepolarizing r. an agent, e.g., tubocurarine, that paralyzes skeletal muscle without depolarization of the motor endplate, as in phase II block. smooth muscle r. an agent, such as an antispasmodic, bronchodilator, or vasodilator, that reduces the tension or tone of smooth (involuntary) muscle.

relaxation (re-lak-sa′shun)
1. Loosening, lengthening, or lessening of tension in a muscle. 2. In nuclear magnetic resonance, r. is the decay in magnetization of protons after the direction of the surrounding magnetic field is changed; the different rates of r. for individual nuclei and tissues are used to provide contrast in imaging. [L. relaxatio (see relax)] cardioesophageal r. r. of the lower esophageal sphincter, which can allow reflux of acidic gastric contents into the lower esophagus, producing esophagitis. isometric r. decrease in tension of a muscle while the length remains constant because of fixation of the ends. isovolumetric r. SYN: isovolumic r.. isovolumic r. that part of the cardiac cycle between the time of aortic valve closure and mitral opening, during which the ventricular muscle decreases its tension without lengthening so that ventricular volume remains unaltered; the heart is never precisely isovolumetric (vs. isovolumic) except during long diastoles with a midiastolic period of diastasis. SYN: isovolumetric r.. longitudinal r. in nuclear magnetic resonance, the return of the magnetic dipoles of the hydrogen nuclei (magnetization vector) to equilibrium parallel to the magnetic field, after they have been flipped 90°; varies in rate in different tissues, taking up to 15 s for water. See TI. SYN: spin-lattice r., spin-spin r.. spin-lattice r. SYN: longitudinal r.. spin-spin r. SYN: longitudinal r.. transverse r. in nuclear magnetic resonance, the decay of the nuclear magnetization vector at right angles to the magnetic field after the 90° pulse is turned off; the signal is called free induction decay. See T2. Cf.:longitudinal r..

relaxin (re-lak′sin)
A polypeptide hormone secreted by the corpora lutea of mammalian species during pregnancy. Facilitates the birth process by causing a softening and lengthening of the pubic symphysis and cervix; it also inhibits contraction of the uterus and may play a role in timing of parturition. SYN: cervilaxin, ovarian hormone, releasin. [relax + -in]

relearning (re-lern′ing)
The process of regaining a skill or ability that has been partially or entirely lost; savings involved in r., as compared with original learning, give an index of the degree of retention.

SYN: relaxin.

reliability (re-li-a-bil′i-te)
The degree of stability exhibited when a measurement is repeated under identical conditions. See correlation coefficient, r. coefficient. [M.E. relien, fr. O.Fr. relier, fr. L. religo, to bind] equivalent form r. in psychology, the consistency of measurement based on the correlation between scores on two similar forms of the same test taken by the same individual. SEE ALSO: r. coefficient. interjudge r. in psychology, the consistency of measurement obtained when different judges or examiners independently administer the same test to the same individual. SYN: interrater r.. interrater r. SYN: interjudge r.. test-retest r. in psychology, the consistency of measurement based on the correlation between test and retest scores for the same individual. SEE ALSO: coefficient, r..

relief (re-lef′)
1. Removal of pain or distress, physical or mental. 2. In dentistry, reduction or elimination of pressure from a specific area under a denture base. SEE ALSO: r. area, r. chamber. [see relieve]

relieve (re-lev′)
To free wholly or partly from pain or discomfort, either physical or mental. [through O. Fr. fr. L. re-levo, to lift up, lighten]

reline (re′lin′)
In dentistry, to resurface the tissue side of a denture with new base material to make it fit more accurately. SEE ALSO: rebase.

1. Acronym for rapid eye movements, under movement. 2. Acronym for reticular erythematous mucinosis. See R. syndrome.

Abbreviation for roentgen-equivalent-man.

Ernst J., German neurologist, 1848–1911. See R. reflex, R. sign.

Robert, Polish-German anatomist and histologist, 1815–1865. See R. nuclear division, R. fibers, under fiber, R. ganglia, under ganglion, R. plexus.

remediable (re-me′de-a-bl)
Curable. [L. remediabilis, fr. remedio, to cure]

remedial (re-me′de-al)
Curative or acting as a remedy.

remedy (rem′e-de)
An agent that cures disease or alleviates its symptoms. [L. remedium, fr. re-, again, + medeor, cure]

remineralization (re′min′er-al-i-za′shun)
1. The return to the body or a local area of necessary mineral constituents lost through disease or dietary deficiencies; commonly used in referring to the content of calcium salts in bone. 2. In dentistry, a process enhanced by the presence of fluoride whereby partially decalcified enamel, dentin, and cementum become recalcified by mineral replacement.

reminiscence (rem-i-nis′sens)
In the psychology of learning, an improvement in recall, over that shown on the last trial, of incompletely learned material after an interval without practice. [L. reminiscentiae, from reminiscor, to remember]

remission (re-mish′un)
1. Abatement or lessening in severity of the symptoms of a disease. 2. The period during which such abatement occurs. [L. remissio, fr. re-mitto, pp. -missus, to send back, slacken, relax] spontaneous r. disappearance of symptoms without formal treatment.

remit (re-mit′)
To become less severe for a time without absolutely ceasing. [see remission]

remittence (re-mit′ens)
A temporary amelioration, without actual cessation, of symptoms.

remittent (re-mit′ent)
Characterized by temporary periods of abatement of the symptoms of a disease.

remnant (rem′nant)
Something remaining, a residue or vestige. [O. Fr., fr. remaindre, to remain, fr. L. remaneo]

remodeling (re-mod′el-ing)
1. A cyclic process by which bone maintains a dynamic steady state through sequential resorption and formation of a small amount of bone at the same site; unlike the process of modeling, the size and shape of remodeled bone remain unchanged. 2. Any process of reshaping or reorganizing. heart chamber r. an architectural change in any cardiac chamber (usually one or both ventricles) due to a pathologic or normal (neonatal) stimulus.

ren, gen. renis, pl .renes (ren, re′nis, re′nez)
SYN: kidney. [L.]

renal (re′nal)
SYN: nephric.

renaturation (re-na-tu-ra′shun)
The conversion of a denatured and inactive macromolecule back to its natured and bioactive configuration.

renculus (ren′koo-lus)
1. SYN: cortical lobules of kidney, under lobule. 2. SYN: reniculus (2) .

Henri J.L.M., French physician, 1844–1902. See R.-Osler-Weber syndrome.

See reno-.

renicapsule (ren′i-kap′sool)
The capsule of the kidney. [reni- + L. capsula, capsule]


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