| posterior cusp of atrioventricular valve | The posterior leaflet of either the tricuspid or mitral valves. Synonym: cuspis posterior valvae atrioventricularis dextrae/sinistrae. (05 Mar 2000) |
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| incomplete atrioventricular block | Impulses penetrate the atrioventricular junction in some relation to the ventricular rate. Synonym: incomplete atrioventricular block. (05 Mar 2000) |
| incomplete atrioventricular dissociation | A-V dissociation interrupted by ventricular captures. (05 Mar 2000) |
| tachycardia, atrioventricular nodal reentry | A tachycardia characterised by rates between 150 and 250 beats per minute and a qrs complex of supraventricular origin. (12 Dec 1998) |
| trunk of atrioventricular bundle | The singular initial portion (stem) of the atrioventricular bundle which passes from the atrioventricular node into the right trigone of the fibrous skeleton of the heart and along the periphery of the membranous interventricular septum; upon reaching the muscular interventricular septum, the trunk terminates by dividing into the right and left crura of the atrioventricular bundle. Synonym: truncus fascicularis atrioventricularis. (05 Mar 2000) |
| left atrioventricular valve | <anatomy, cardiology> The heart valve that divides the left atrium and left ventricle. During left atrial contraction, the mitral valve opens to allow blood to flow into the left ventricle. Upon closure, the mitral valve prohibits the regurgitation of blood back into the left atrium. The mitral valve is the only heart valve that has only 2 valve cusps (all others have 3). (13 Nov 1997) |
| left crus of atrioventricular bundle | The left leg or branch of the atrioventricular bundle which separates from the atrioventricular bundle just below the membranous portion of the interventricular septum to descend the septal wall of the left ventricle and begins to ramify subendocardially. Synonym: crus sinistrum fasciculi atrioventricularis. (05 Mar 2000) |
| bufadienolides (two double bonds) | Bufatrienolides (three double bonds), etc; they have varying numbers of hydroxyl groups at positions 3, 5, 14, and 16, and these may be further substituted. For structure, see steroids. (05 Mar 2000) |
| bufenolides (one double bond) | (05 Mar 2000) |
| carbon-carbon double bond isomerases | <enzyme> Enzymes that catalyze the shifting of a carbon-carbon double bond from one position to another within the same molecule. Registry number: EC 5.3.3 (12 Dec 1998) |
| RNA, double-stranded | RNA consisting of two strands as opposed to the more prevalent single-stranded RNA. most of the double-stranded segments are formed from transcription of DNA by intramolecular base-pairing of inverted complementary sequences separated by a single-stranded loop. Some double-stranded segments of RNA are normal in all organisms. (12 Dec 1998) |
| conjugated double bonds | Two or more double bond separated by each single bond. (05 Mar 2000) |
| prospective, randomised, double-blind clinical trial | <statistics> A clinical trial in which the method for analysing data has been specified in the protocol before the study has begun (prospective), the patients have been randomly assigned to receive either the study drug or alternative treatment, and in which neither the patient nor the physician conducting the study know which treatment is being given to the patient. (13 Nov 1997) |
| double | 1. To increase by adding an equal number, quantity, length, value, or the like; multiply by two; to double a sum of money; to double a number, or length. "Double six thousand, and then treble that." (Shak) 2. To make of two thicknesses or folds by turning or bending together in the middle; to fold one part upon another part of; as, to double the leaf of a book, and the like; to clinch, as the fist; often followed by up; as, to double up a sheet of paper or cloth. "Then the old man Was wroth, and doubled up his hands." (Tennyson) 3. To be the double of; to exceed by twofold; to contain or be worth twice as much as. "Thus reenforced, against the adverse fleet, Still doubling ours, brave Rupert leads the way." (Dryden) 4. To pass around or by; to march or sail round, so as to reverse the direction of motion. "Sailing along the coast, the doubled the promontory of Carthage." (Knolles) 5. To unite, as ranks or files, so as to form one from each two. Origin: OE. Doblen, dublen, doublen, F. Doubler, fr. L. Duplare, fr. Duplus. See Double. 1. Twice as much; twice the number, sum, quantity, length, value, and the like. "If the thief be found, let him pay double." (Ex. Xxii. 7) 2. Among compositors, a doublet (see Doublet. 2); among pressmen, a sheet that is twice pulled, and blurred. 3. That which is doubled over or together; a doubling; a plait; a fold. "Rolled up in sevenfold double Of plagues." (Marston) 4. A turn or circuit in running to escape pursues; hence, a trick; a shift; an artifice. "These men are too well acquainted with the chase to be flung off by any false steps or doubles." (Addison) 5. Something precisely equal or counterpart to another; a counterpart. Hence, a wraith. "My charming friend . . . Has, I am almost sure, a double, who preaches his afternoon sermons for him." (Atlantic Monthly) 6. A player or singer who prepares to take the part of another player in his absence; a substitute. 7. Double beer; strong beer. 8. A feast in which the antiphon is doubled, hat is, said twice, before and after the Psalms, instead of only half being said, as in simple feasts. 9. A game between two pairs of players; as, a first prize for doubles. 10. An old term for a variation, as in Bach's Suites. 1. Twofold; multiplied by two; increased by its equivalent; made twice as large or as much, etc. "Let a double portion of thy spirit be upon me." (2 Kings II. 9) "Darkness and tempest make a double night." (Dryden) 2. Being in pairs; presenting two of a kind, or two in a set together; coupled. "[Let] The swan, on still St. Mary's lake, Float double, swan and shadow." (Wordsworth) 3. Divided into two; acting two parts, one openly and the other secretly; equivocal; deceitful; insincere. "With a double heart do they speak." (Ps. Xii. 2) 4. <botany> Having the petals in a flower considerably increased beyond the natural number, usually as the result of cultivation and the expense of the stamens, or stamens and pistils. The white water lily and some other plants have their blossoms naturally double. Double is often used as the first part of a compound word, generally denoting two ways, or twice the number, quantity, force, etc, twofold, or having two. Double base, or Double bass . Same as Double-quick. Double window, a window having two sets of glazed sashes with an air space between them. Origin: OE. Doble, duble, double, OF. Doble, duble, double, F. Double, fr. L. Duplus, fr. The root of duo two, and perh. That of plenus full; akin to Gr. Double. See Two, and Full, and cf. Diploma, Duple. Source: Websters Dictionary (01 Mar 1998) |
| double antibody immunoassay | A method of separating antibody-bound antigen (e.g., insulin) from free antigen by precipitating the former with antibody specific for immunoglobulin. Synonym: double antibody immunoassay, double antibody method. (05 Mar 2000) |