| bun | Blood urea nitrogen (BUN) is a metabolic by product (in the liver) from the breakdown of blood, muscle and protein. Blood urea nitrogen can be measured from a simple venipuncture specimen. Abnormal elevation in the blood urea nitrogen can indicate renal disease, dehydration, congestive heart failure, gastrointestinal bleeding, starvation, shock or urinary tract obstruction (by tumour or prostate gland). Low BUN level can indicate liver disease, malnutrition or a low protein diet. Normal BUN levels should be between 7 and 20 mg/dl (milligrams per decilitre). (27 Sep 1997) |
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| bunaftine | <chemical> N-butyl-n-(2-(diethylamino)ethyl)-1-naphthamide. A proposed antiarrhythmic that prolongs myocardial refractory period and stabilises cell membranes. Pharmacological action: anti-arrhythmia agents. Chemical name: 1-Naphthalenecarboxamide, N-butyl-N-(2-(diethylamino)ethyl)- (12 Dec 1998) |
| bunamidine hydrochloride | N,N-Dibutyl-4-hexyloxynaphthamidine monohydrochloride;an anthelmintic. (05 Mar 2000) |
| bunch | 1. A protuberance; a hunch; a knob or lump; a hump. "They will carry . . . Their treasures upon the bunches of camels." (Isa. Xxx. 6) 2. A collection, cluster, or tuft, properly of things of the same kind, growing or fastened together; as, a bunch of grapes; a bunch of keys. 3. <chemical> A small isolated mass of ore, as distinguished from a continuous vein. Origin: Akin to OSw. & Dan. Bunke heap, Icel. Bunki heap, pile, bunga tumour, protuberance; cf. W. Pwng cluster. Cf. Bunk. Source: Websters Dictionary (01 Mar 1998) |
| bunch grass | Any of a number of perennial grasses (family Gramineae) which grow in tight clumps and regenerate each year from deep roots. (09 Oct 1997) |
| bunchberry | <botany> The dwarf cornel (Cornus Canadensis), which bears a dense cluster of bright red, edible berries. Source: Websters Dictionary (01 Mar 1998) |
| bunching | <radiobiology> A technique for spatial compression of a pulse in a beam of charged particles. (09 Oct 1997) |
| bunchy | 1. Swelling out in bunches. "An unshapen, bunchy spear, with bark unpiled." (Phaer) 2. Growing in bunches, or resembling a bunch; having tufts; as, the bird's bunchy tail. 3. <chemical> Yielding irregularly; sometimes rich, sometimes poor; as, a bunchy mine. Source: Websters Dictionary (01 Mar 1998) |
| bundle | 1. To prepare for departure; to set off in a hurry or without ceremony. 2. To sleep on the same bed without undressing; applied to the custom of a man and woman, especially lovers, thus sleeping. "Van Corlear stopped occasionally in the villages to eat pumpkin pies, dance at country frolics, and bundle with the Yankee lasses." (W. Irving) Source: Websters Dictionary (01 Mar 1998) |
| bundle bone | Immature bone containing thick bundles of collagen fibres arranged nearly parallel to one another with osteocytes in between; a similar type of bone is found in regions penetrated by fibres of Sharpey, as at ligament and tendon attachments. (05 Mar 2000) |
| bundle divertor | <radiobiology> Divertor concept where a toroidal field coil extracts a bundle of toroidal field lines (flux) and forms a separatrix in the toroidal field. (Hard to do and tends to mess up axisymmetry of the torus, not used much.) (09 Oct 1997) |
| bundle of His | <cardiology, physiology> Small band of specialised cardiac muscle fibres that originates in the atrioventricular node and extends into the membranous part of the interventricular septum. (12 Dec 1998) |
| bundle of Rasmussen | A bundle of fibres that originates from the periolivary nuclei bilaterally, exits the brainstem on the vestibular nerve, joins the cochlear nerve in the inner ear, and terminates on outer hair cells. Synonym: bundle of Rasmussen, olivocochlear fibres. (05 Mar 2000) |
| bundle-branch block | <cardiology, physiology> Abnormal conduction through one of the conductive branches which normally supply the right and left ventricles. Usually results in delayed conduction though either the right or left bundle branches where one ventricle is excited before the other because of absence of conduction in one of the branches of the bundle of His. Intraventricular block due to interruption of conduction in one of the two main branches of the bundle of His and manifested in the electrocardiogram by marked prolongation of the QRS complex; block of each branch has distinctive QRS morphology. (05 Mar 2000) |
| bungarotoxins | Neurotoxic proteins from the venom of the banded or formosan krait (bungarus multicinctus, an elapid snake). Alpha-bungarotoxin blocks nicotinic acetylcholine receptors and has been used to isolate and study them; beta- and gamma-bungarotoxins act presynaptically causing acetylcholine release and depletion. Both alpha and beta forms have been characterised, the alpha being similar to the large, long or type II neurotoxins from other elapid venoms. (12 Dec 1998) |