|Medical Dictionary - Dictionary of Medicine and Human Biology|
A substance that promotes healing or union.
Solidification into a firm dense mass; applied especially to inflammatory induration of a normally aerated lung due to the presence of cellular exudate in the pulmonary alveoli as commonly seen in pneumonia. [L. consolido, to make thick, condense, fr. solidus, solid]
Of the same species. [L. con-, with, + specific]
The visibility of a structure of interest on a radiograph, a function of the inherent contrast of the structure and the complexity (noise) of the surrounding image.
The quality of being unchanging [L. constantia, fr. consto, to stand still] color c. unchanging perception of the color of an object despite changes in lighting or viewing conditions. object c. 1. the tendency for objects to be perceived as unchanging despite variations in the positions in and conditions under which the objects are observed; e.g., a book's shape is always perceived as a rectangle regardless of the visual angle from which it is viewed. 2. in psychoanalysis, the relatively enduring emotional investment in another person.
A quantity that, under stated conditions, does not vary with changes in the environment. association c. 1. in experimental immunology, a mathematical expression of hapten-antibody interaction: average association c., K = [hapten-bound antibody]/[free antibody][free hapten]; 2. (Ka) the equilibrium c. involved in the association of two or more compounds or ions into a new compound; the reciprocal of the dissociation c.. SYN: binding c.. Avogadro c. SYN: Avogadro number. binding c. SYN: association c.. decay c. the fractional change in the number of atoms of a radionuclide that occurs in unit time; the c. λ in the equation for the fraction (dN/N) of the number of atoms (N) of a radionuclide disintegrating in time dt, dN/N = −λdt. SYN: disintegration c., radioactive c., transformation c.. diffusion c. SYN: diffusion coefficient. disintegration c. SYN: decay c.. dissociation c. (Kd, K) the equilibrium c. involved in the dissociation of a compound into two or more compounds or ions. The reciprocal of the association c. (2). dissociation c. of an acid (Kd, Ka) expressed by the general equation [H+][A−]/[HA] = Ka, where HA is the undissociated acid. dissociation c. of a base (Kb) expressed by the general equation [B+][OH−]/[BOH] = Kb, where BOH is the undissociated base. dissociation c. of water expressed by the equation [H+][OH−] = Kw = 10−14 at 25°C. equilibrium c. (Keq) in the reaction A + B ⇆ C + D at equilibrium ( i.e., no net change in concentrations of A, B, C, or D), the concentrations of the four components are related by the equation Keq = [C][D]/[A][B]; Keq is the equilibrium c. If any component in the reaction has a multiplier ( e.g., H2 ⇆ 2H), that multiplier appears as an exponent in the calculation of K ( e.g., Keq = [H]2/[H2]). When this equation is applied to the ionization of a substance in solution, Keq is called the dissociation c. (Kd) and its negative logarithm (base 10) is the pKd. SEE ALSO: Henderson-Hasselbalch equation, mass-action ratio. Faraday c. (F) faraday. flotation c. (Sf) characteristic sedimentation behavior of a lipoprotein fraction of plasma in a centrifugal field in a medium of appropriate density, achieved by adding a salt or D2O to the plasma. SYN: negative S, Svedberg of flotation. gas c. (R) R = 8.314 × 107 ergs K−1 mol−1 = 8.314 J K−1 mol−1. Hill c. SYN: Hill coefficient. Michaelis c. 1. the true dissociation c. for the enzyme-substrate binary complex in a single-substrate rapid equilibrium enzyme-catalyzed reaction (usually symbolized by Ks); 2. the concentration of the substrate at which half the true maximum velocity of an enzyme-catalyzed reaction is achieved (when velocities are measured under initial rate and steady state conditions); the ratio of rate constants (k2 + k3)/k1 in the single-substrate enzyme-catalyzed reaction: E + S ⇆ ES ⇆ E + products where E represents the free enzyme, S is the substrate, and ES is the central binary complex. The expression for the Michaelis c. will be more complex for multisubstrate reactions. An apparent Michaelis c. is a c. determined either under conditions that are not strictly steady state and initial rate or one that varies with the concentration of one or more cosubstrates. See Michaelis-Menten equation. SYN: Michaelis-Menten c.. Michaelis-Menten c. (Km) SYN: Michaelis c.. Newtonian c. of gravitation (G) a universal c. relating the gravitational force, F, attracting two masses, m1 and m2, toward each other when they are separated by a distance, r, in the equation: F = G(m1m2/r2); it has the value of 6.67259 × 10−8 dyne cm2 g−2 = 6.67259 × 10−11 m3 kg−1 s−2 in SI units. permeability c. a measure of the ease with which an ion can cross a unit area of membrane driven by a 1.0 mol/L difference in concentration; usually expressed in centimeters per second. Cf.:permeability coefficient. Planck c. (h) a c., 6.6260755 × 10−34 J &chmpnt; s or 6.6260755 × 10−27 erg-seconds = 6.6260755 × 10−34 J Hz−1. radioactive c. (Λ) SYN: decay c.. rate constants (k) proportionality constants equal to the initial rate of a reaction divided by the concentration of the reactant(s); e.g., in the reaction A → B + C, the rate of the reaction equals −d[A]/dt = k1[A]. The rate c. k1 is a unimolecular rate c. since there is only one molecular species reacting and has units of reciprocal time ( e.g., s−1). For the reverse reaction, B + C → A, the rate equals −d[B]/dt = d[A]/dt = k2[B][C]. The rate c. k2 is a bimolecular rate c. and has units of reciprocal concentration-time ( e.g., M−1 s−1). SYN: velocity constants. sedimentation c. the c. s in Svedberg equation for estimating the molecular weight of a protein from the rate of movement in a centrifugal field:where M is the molecular weight, R the gas c., T the absolute temperature, D the diffusion c. (in square centimeters per second), V the partial specific volume of the protein, ρ the density of the solvent. The c. s, with dimensions of time per unit of field force (s = drb/dt ω2ro where rb is the position at time t, r0 is the position at time 0, and ω is the angular velocity) is usually between 1 × 10−13 and 200 × 10−13 s. The Svedberg unit (S) is arbitrarily set at 1 × 10−13 s and is very often used to describe the sedimentation rate of macromolecules; e.g., 4S RNA. SYN: sedimentation coefficient. specificity c. ratio of the maximum velocity (Vmax) or kcat to the true Km value for a specific substrate in an enzyme-catalyzed reaction. time c. that part of a circuit that determines the time interval over which the rate of electrical events will be averaged; in pulmonary physiology, the factors determining rate of flow in the airways. transformation c. SYN: decay c.. velocity constants (k) SYN: rate constants.
In psychiatry, all the factors that determine a particular action. [L.L. constellatio, fr. cum, together, + stella, star]
To cause constipation.
Suffering from constipation.
A condition in which bowel movements are infrequent or incomplete. SYN: costiveness. [L. con-stipo, pp. -atus, to press together]
1. The physical makeup of a body, including the mode of performance of its functions, the activity of its metabolic processes, the manner and degree of its reactions to stimuli, and its power of resistance to the attack of pathogenic organisms or other disease processes. 2. In chemistry, the number and kind of atoms in the molecule and the relation they bear to each other. [L. constitutio, c., disposition, fr. constituo, pp. -stitutus, to establish, fr. statuo, to set up]
1. Relating to a body's constitution. 2. General; relating to the system as a whole; not local.
1. See c. enzyme. 2. In genetics, descriptive of a gene that is controlled by constantly active promoter.
SYN: constriction (1) . c. bronchoaortica esophagea thoracic constriction of esophagus. c. diaphragmatica esophagea diaphragmatic constriction of esophagus. c. partis thoracicae esophagea [TA] SYN: thoracic constriction of esophagus. c. pharyngoesophagealis [TA] SYN: pharyngoesophageal constriction. c. phrenica esophagea [TA] SYN: diaphragmatic constriction of esophagus.
1. [TA] A normally or pathologically constricted or narrowed portion of a structure. SYN: constrictio [TA] . SEE ALSO: stricture, stenosis. 2. The act or process of binding or contracting, becoming narrowed; the condition of being constricted. squeezed. 3. A subjective sensation of pressure or tightness, as if the body or any part were tightly bound or squeezed. [L. con-stringo, pp. -strictus, to draw together] broncho-aortic c. thoracic c. of esophagus. diaphragmatic c. of esophagus [TA] normal narrowing of the esophagus, demonstrated radiographically following a barium swallow, caused by the passage of the esophagus through the esophageal hiatus of the diaphragm. SYN: constrictio phrenica esophagea [TA] , constrictio diaphragmatica esophagea&star, inferior esophageal c.. esophageal constrictions three narrowings of the esophagus normally demonstrated radiographically following a barium swallow. SEE ALSO: pharyngoesophageal c., thoracic c. of esophagus, diaphragmatic c. of esophagus. SYN: impressions of esophagus. inferior esophageal c. SYN: diaphragmatic c. of esophagus. middle esophageal c. SYN: thoracic c. of esophagus. pharyngoesophageal c. [TA] normal narrowing of the alimentary tract, demonstrated radiographically following a barium swallow, at the junction of the pharynx with the esophagus (C5 vertebral level) caused by the tonic or active contraction of the cricopharyngeal part of the inferior constrictor of the pharynx (upper esophageal sphincter). SEE ALSO: cricopharyngeal part of inferior constrictor (muscle) of pharynx. SYN: constrictio pharyngoesophagealis [TA] , upper esophageal c.. primary c. the narrowing between the two arms of the chromosome represented by the centromere. pyloric c. circular groove on the external aspect of the gut at the gastroduodenal junction overlying the pyloric sphincter, thus demarcating the pyloric orifice. secondary c. a subsidiary narrowing of the chromosome associated in some cases with satellites, e.g., the short arms of acrocentric autosomes. thoracic c. of esophagus [TA] normal left-sided narrowing of the esophagus, demonstrated radiographically following a barium swallow, at the T4–T5 vertebral level, where the esophagus is impressed by the left main bronchus and the arch of the aorta. SYN: constrictio partis thoracicae esophagea [TA] , broncho-aortic c.&star, constrictio bronchoaortica esophagea&star, middle esophageal c.. upper esophageal c. SYN: pharyngoesophageal c.. constrictions of ureter normal physiological narrowings of the ureter observable in a pyelogram; the uppermost occurs at the origin of the ureter from the renal pelvis; a second occurs as the ureter crosses the iliac vessels and pelvic brim; the inferiormost occurs as the ureter penetrates the wall of the urinary bladder.
constrictor (kon-strik′ter, -tor)
1. Anything that binds or squeezes a part. SEE ALSO: inferior c. (muscle) of pharynx, middle c. (muscle) of pharynx, superior pharyngeal c. (muscle). 2. A muscle, the action of which is to narrow a canal; a sphincter. [L. fr. constringo, to draw together]
The combination of a bone graft, metal instrumentation, prosthetic devices and/or bone cement applied to a specific level of the spinal column in the setting of segmental spinal instability.
A person about whose future offspring the genetic counselor is to make predictions; not to be confused with proband. [consult (for counsel) + L. -andus, gerundive suffix] dummy c. a person in the line of descent from the leading ancestor to the c. proper; for logical simplicity, the dummy c. is analyzed as if the c. proper.
1. A physician or surgeon who does not take full responsibility for a patient, but acts in an advisory capacity, deliberating with and counseling the attending physician or surgeon. 2. A member of a hospital staff who has no active service but stands ready to advise in any case, at the request of the attending physician or surgeon. [L. consulto, pp. -atus, to deliberate, ask advice]
Meeting of two or more physicians or surgeons to evaluate the nature and progress of disease in a particular patient and to establish diagnosis, prognosis, and/or therapy.
1. The using up of something, especially the rate at which it is used. 2. Obsolete term for a wasting of the tissues of the body, usually tuberculous. [L. con-sumo, pp. -sumptus, to take up wholly, use up, waste] oxygen c. (VO2) 1. (Qo or Qo2), the rate at which oxygen is used by a tissue; units: microliters of oxygen STPD used per milligram of tissue per hour; 2. (Vo2), the rate at which oxygen enters the blood from alveolar gas, equal in the steady state to the c. of oxygen by tissue metabolism throughout the body; units: milliliters of oxygen STPD used per minute or mmol/min.
Relating to, or suffering from, consumption.
1. The touching or apposition of two bodies. 2. A person who has been exposed to a contagious disease. [L. con- tingo, pp. -tactus, to touch, seize, fr. tango, to touch] balancing c. 1. the contacts between upper and lower dentures on the balancing or mediotrusive side for the purpose of stabilizing the dentures; 2. the contacts between upper and lower dentures at the opposite side from the working or laterotrusive side (anteroposteriorly or laterally) for the purpose of stabilizing the dentures; 3. the contacts between upper and lower natural or artificial teeth at the opposite side from the working or laterotrusive side. SYN: balancing occlusal surface. centric c. SYN: centric occlusion. deflective occlusal c. a condition of tooth contacts which diverts the mandible from a normal path of closure to centric jaw relation. SYN: cuspal interference, interceptive occlusal c., premature c.. initial c. 1. the first meeting of opposing teeth upon elevation of the mandible toward the maxillae; 2. the initial occlusal c. of opposing teeth when the jaw is closed. interceptive occlusal c. SYN: deflective occlusal c.. premature c. SYN: deflective occlusal c.. proximal c., proximate c. the area where the surfaces of two adjacent teeth in the same arch touch. c. with reality correctly interpreting external phenomena in relation to the norms of one's social or cultural milieu. working contacts working or occlusion; contacts of teeth made on the side of the occlusion toward which the mandible has been moved. SYN: working bite, working occlusion.
Any of a heterogeneous group of allergens that elicit manifestations of delayed hypersensitivity by direct contact with skin or mucosa.
1. SYN: contagium. 2. Transmission of infection by direct contact, droplet spread, or contaminated fomites. The term originated long before development of modern ideas of infectious disease and has since lost much of its significance, being included under the more inclusive term “communicable disease.” 3. Production via suggestion or imitation of a neurosis or psychosis in several or more members of a group. [L. contagio; fr. contingo, to touch closely] psychic c. communication of a nervous disorder or lesser psychological symtoms by imitation, as in mass hysteria.
Relating to contagion; communicable or transmissible by contact with the sick or their fresh secretions or excretions.
The quality of being contagious.
The agent of an infectious disease. SYN: contagion (1) . [L. a touching]
The concept of regional or global eradication of communicable disease, proposed by Fred Lowe Soper (1893-1977) in 1949 for the eradication of smallpox.
An impurity; any material of an extraneous nature associated with a chemical, a pharmaceutical preparation, a physiologic principle, or an infectious agent.
To cause or result in contamination. [L. con-tamino, to mingle, corrupt]
1. The presence of an infectious agent on a body surface; also on or in clothes, bedding, toys, surgical instruments or dressings, or other inanimate articles or substances including water, milk, and food or that infectious agent itself. 2. In epidemiology, the situation that exists when a population being studied for one condition or factor also possesses other conditions or factors that modify results of the study. 3. Freudian term for a fusion and condensation of meanings of words, percepts, or motivations for behavior. 4. The presence of foreign material that adulterates or renders impure a material whose composition is degraded. [L. contamino, pp. -atus, to stain, defile]
1. That which is contained within something else, usually in this sense in the plural form, contents. 2. In psychology, the form of a dream as presented to consciousness. 3. Ambiguous usage for concentration (3); e.g., blood hemoglobin c. could mean either its concentration or the product of its concentration and the blood volume. [L. contentus, fr. con- tineo, pp. -tentus, to hold together, contain] carbon dioxide c. the total carbon dioxide available from serum or plasma following addition of acid; measured routinely in hospital laboratories as a component of electrolyte profiles. GC c. the amount of guanine and cytosine in a polynucleic acid usually expressed in mole fraction (or percentage) of total bases; the melting temperature of such biopolymers varies with the GC c.. latent c. the hidden, unconscious meaning of thoughts or actions, especially in dreams or fantasies. manifest c. those elements of fantasy and dreams which are consciously available and reportable.
See c. map.
1. Contact without actual continuity, e.g., the contact of the bones entering into the formation of a cranial suture. Cf.:continuity. 2. Occurrence of two or more objects, events, or mental impressions together in space (spatial c.) or time (temporal c.). [L. contiguus, touching, fr. contingo, to touch]
Adjacent or in actual contact.
1. The ability to retain urine and/or feces until a proper time for their discharge. 2. Moderation, temperance, or self-restraint in respect to the appetites, especially to sexual intercourse. [L. continentia, fr. con- tineo, to hold back]
Continuous; without intermission; said especially of protracted fever without apyretic intervals, such as typhoid fever, compared with the paroxysms of fever in malaria. [L. continuo, to join together, make continuous]
Absence of interruption, a succession of parts intimately united, e.g., the unbroken conjunction of cells and structures that make up a single bone of the skull. Cf.:contiguity. [L. continuus, continued]
1. The outline of a part; the surface configuration. 2. In dentistry, to restore the normal outlines of a broken or otherwise misshapen tooth, or to create the external shape or form of a prosthesis. [L. con- (intens.), + torno, to turn (in a lathe), fr. tornus, a lathe] flange c. the design of the flange of a denture. gingival c. the shape or form of the gingiva, either natural or artificial, around the necks of the teeth. SYN: gum c.. gum c. SYN: gingival c.. height of c. See height of c..
Opposed, against. SEE ALSO: counter-. Cf.:anti-. [L.]
1. One of the double or triple angles in the shank of an instrument by means of which the cutting edge or point is brought into the axis of the handle. 2. An extension piece added to the end of a dental handpiece which, through a set of bevel gears, changes the angle of the axis of rotation of the bur in relation to the axis of the handpiece.
A bevel located on the side opposite the customary side.
Prevention of conception or impregnation. emergency hormonal c. SYN: morning after pill. SYN: postcoital c.. postcoital c. SYN: emergency hormonal c..
1. An agent for the prevention of conception. 2. Relating to any measure or agent designed to prevent conception. [L. contra, against, + conceptive] barrier c. a mechanical device designed to prevent spermatozoa from penetrating the cervical os; usually used in combination with a spermicidal agent, i.e., vaginal diaphragm. combination oral c. a mixture of a steroid having progestational activity and an estrogen. intrauterine c. device See intrauterine c. devices, under device. oral c. any orally effective preparation designed to prevent conception.
1. (kon-trakt′)To shorten; to become reduced in size; in the case of muscle, either to shorten or to undergo an increase in tension. 2. (kon-trakt′)To acquire by contagion or infection. 3. (kon′trakt)An explicit bilateral commitment by psychotherapist and patient to a defined course of action to attain the goal of the psychotherapy. [L. con-traho, pp. -tractus, to draw together]
Having the property of contracting.
The ability or property of a substance, especially of muscle, of shortening, or becoming reduced in size, or developing increased tension. cardiac c. a measure of cardiac pump performance, the degree to which muscle fibers can shorten when activated by a stimulus independent of preload and afterload.
contraction (C) (kon-trak′shun)
1. A shortening or increase in tension; denoting the normal function of muscle. 2. A shrinkage or reduction in size. 3. Heart beat, as in premature c..beat. [L. contractus, drawn together] after-c. aftercontraction. anodal closure c. (ACC, AnCC) obsolete term for the momentary c. of a muscle under the influence of the positive pole when the electrical circuit is established. anodal opening c. (AnOC, AOC) obsolete term for the momentary c. of a muscle under the influence of the positive pole when the circuit is broken. automatic c. SYN: automatic beat. Braxton Hicks c. rhythmic myometrial activity occurring during the course of a pregnancy that usually causes no pain for the patient. cathodal closure c. (CaCC, CCC) obsolete term for the momentary c. of a muscle under the influence of the negative pole when an electrical circuit is established. cathodal opening c. (CaOC, COC) obsolete term for the momentary c. of a muscle under the influence of the negative pole when the circuit is broken. closing c. c. produced at the time of closing of the circuit when using direct current to stimulate the muscle. escape c. SYN: escape beat. escape ventricular c. an escape beat arising in the ventricle. fibrillary contractions contractions occurring spontaneously in individual muscle fibers; they are seen commonly a few days after damage to the motor nerves supplying the muscle, and this type of activity is distinguished from fasciculation, which is related to activation of motor units. front-tap c. c. of the calf muscles when the anterior surface of the leg is struck. SYN: Gowers c.. Gowers c. SYN: front-tap c.. hourglass c. constriction of the middle portion of a hollow organ, such as the stomach or the gravid uterus. hunger contractions strong contractions of the stomach associated with hunger pains. idiomuscular c. SYN: myoedema. isometric c. force development at constant length. Cf.:isotonic c.. isotonic c. shortening at constant force development. Cf.:isometric c.. SYN: isotonic exercise. myotatic c. a reflex c. of a skeletal muscle that occurs as a result of stimulation of the stretch receptors in the muscle, i.e., as part of a myotatic reflex. opening c. a c. produced at the time of opening the circuit when using direct current to stimulate the muscle or a motor nerve. paradoxical c. a tonic c. of the anterior tibial muscles when a sudden passive dorsal flexion of the foot is made. postural c. maintenance of muscular tension (usually isometric) sufficient to maintain posture. premature c. extrasystole. reflex detrusor c. normal coordinated function of the bladder with sustained contractions of the bladder matched by simultaneous relaxation of the sphincteric outlet mechanisms to empty the bladder. tetanic c. tetanus (2) . tonic c. sustained c. of a muscle, as employed in the maintenance of posture. uterine c. rhythmic activity of the myometrium associated with menstruation, pregnancy, or labor.
Static muscle shortening due to tonic spasm or fibrosis, to loss of muscular balance, the antagonists being paralyzed or to a loss of motion of the adjacent joint. [L. contractura, fr. con-traho, to draw together] Dupuytren c. a disease of the palmar fascia resulting in thickening and shortening of fibrous bands on the palmar surface of the hand and fingers resulting in a characteristic flexion deformity of the fourth and fifth digits. fixed c. SYN: organic c.. functional c. muscular shortening that ceases during sleep or general anesthesia, caused by prolonged active muscle contraction. ischemic c. of the left ventricle irreversible contraction of the left ventricle of the heart, seen as a complication in the early period of cardiopulmonary bypass and now avoided by appropriate cardioplegic solutions. SYN: myocardial rigor mortis, stone heart. organic c. c., usually due to fibrosis within the muscle that persists whether the subject is conscious or unconscious. SYN: fixed c.. Volkmann c. ischemic c. resulting from irreversible necrosis of muscle tissue, produced by a compartment syndrome; classically involves the forearm flexor muscles.
Fracture of a bone, as in the skull, at a point opposite that where the blow was received. [L. contra, against, counter, + fissura, fissure]
Indicating the contrary, i.e., showing that a method of treatment that would otherwise be proper is inadvisable by special circumstances in the individual case.
Any special symptom or circumstance that renders the use of a remedy or the carrying out of a procedure inadvisable, usually because of risk.
Relating to the opposite side, as when pain is felt or paralysis occurs on the side opposite to that of the lesion. SYN: heterolateral. [L. contra, opposite, + latus, side] c. partner the corresponding structure on the opposite side.
1. A comparison in which differences are demonstrated or enhanced. 2. In radiology, the difference between the image densities of two areas is the c. between them; this is a function of the number of x-ray photons transmitted or the strength of the signals emitted by the two regions and the response of the recording medium. [L. contra, against, + sto, pp. status, to stand] simultaneous c. the enhancement of the visual sensation of white when a white object is viewed adjacent to a black object; the black object also appears blacker as a result of the contiguity of white. Adjacent complementary colors also appear brighter; e.g., green appears a brighter green and red a brighter red if these two colors are viewed side by side. successive c. the visual effect caused by viewing a brightly colored object and then a gray surface; the latter appears tinged with the complementary color of the object. Viewing a surface colored in the complementary color of the object rather than in gray enhances the color intensity of the surface.
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