| beta blockers | A class of drugs that block the action of adrenaline (a beta adrenergic substance) and can relieve stress to the heart muscle. Beta blockers are often used to slow the heart rate or lower the blood pressure. (12 Dec 1998) |
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| beta-blocker | <pharmacology> A large group of medications that act to block specific receptors in the nervous system. A drug that induces adrenergic blockade at either á1 or á2 adrenergic receptors or at both. The effect of beta-blockade results in slowing of the heart rate, reduction in blood pressure and reduced anxiety. Beta-blockers are used in the treatment of angina, heart arrhythmias, high blood pressure, mitral valve prolapse and other conditions. (06 Oct 1997) |
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| medication, beta-blocker | Drugs that antagonise the action of adrenaline (a beta adrenergic substance) and relieve stress to the heart muscle. Beta-blockers are often used to slow the heart rate or lower the blood pressure. (12 Dec 1998) |
| alpha-blocker | An agent that competitively blocks alpha-adrenergic receptors; used in the treatment of hypertension. Synonym: alpha-blocker. (05 Mar 2000) |
| blocker | 1. An instrument used to obstruct a passage. See: blocking agent. (05 Mar 2000) |
| calcium channel-blocker | <pharmacology> A class of drugs that act by selective inhibition of calcium ion influx through or across cell membranes or on the release and binding of calcium in intracellular pools. Calcium channel blockers are used primarily in the treatment of certain heart conditions and stroke. As they are inducers of vascular and other smooth muscle relaxation, they are also used in the treatment of hypertension and cerebrovascular spasms, as myocardial protective agents, and in the relaxation of uterine spasms. Synonym: calcium antagonist, calcium channel-blocker, slow channel-blocking agent. (12 May 2002) |
| H2 blocker | <pharmacology> A class of anti-ulcer medication which work through the inhibition of basal and nocturnal gastric acid secretion by competitive inhibition of the action of histamine at histamine H2 receptor sites on the parietal cells. Drugs of this type block gastric acid secretion and are therefore clinically useful in treating duodenal ulcers. Examples include cimetidine (Tagamet), famotidine (Pepcid), nizatidine (Axid) and ranitidine (Zantac). (27 Sep 1997) |
| androst-5-ene-3 beta,17 beta-diol | <chemical> An adrenal-derived oestrogenic metabolite of dhea. Evidence exist for its use as an endocrine regulator of immune response. Pharmacological action: anabolic steroids. Chemical name: Androst-5-ene-3,17-diol, (3beta,17beta)- (12 Dec 1998) |
| beta-1,3-galactosyl-0-glycosyl-glycoprotein beta-1,3-N-acetylglucosaminyltransferase | <enzyme> Capable of adding a glcnac residue to g1cnacman(3)g1cnac; from mung bean seedlings Registry number: EC 2.4.1.146 Synonym: n-acetylglucosaminyltransferase II, gal3-(glcnac6)galnac-mucin (glcnac--gal)3-glcnactransferase (26 Jun 1999) |
| beta-1,3-galactosyl-O-glycosyl-glycoprotein beta-1,6-acetylglucosaminyl transferase | <enzyme> With EC 2.4.1.148 this is called beta6-glcnac-transferase b Registry number: EC 2.4.1.102 Synonym: gal3-galnac-mucin-6-glcnac transferase, udp-glcnac-gal1-3galnac-r-(glcnac to galnac)-beta1-6glcnac transferase, core 2 glcnac transferase, core 2-n-acetylglucosaminyltransferase, core 2 beta6-gn-t (26 Jun 1999) |
| beta-1,4-mannosyl-glycoprotein beta-1,4-N-acetylglucosaminyltransferase | <enzyme> Induced in preneoplastic stage of liver carcinogenesis promoted by orotic acid in rats; adds "bisecting n-acetylglucosaminyl residue in beta 1,4 linkage to the beta-linked mannose of the core of asparagine-linked oligosaccharides Registry number: EC 2.4.1.144 Synonym: n-acetylglucosaminyltransferase III, udpgnac-glycopeptide beta4-n-acetylglucosaminyl transferase III, udpgnac-magtransferase III, udp-n-acetylglucosamine-beta-d-mannoside beta-1,4-n-acetylglucosaminyltransferase III (26 Jun 1999) |
| beta-hydroxy-beta-methylglutaryl-CoA | -OOCCH2C(OH)(CH3)CH2COS-CoA;a key intermediate in the synthesis of ketone bodies and of steroids. Synonym: 3-hydroxy-3-methylglutaryl-CoA. Beta-hydroxy-beta-methylglutaryl-lyase, an enzyme, found primarily in liver and rumen epithelium that catalyses the formation of acetyl-CoA and acetoacetate from beta-hydroxy-beta-methylglutaryl-CoA; a key step in ketogenesis; a deficiency of this enzyme leads to episodes of severe metabolic acidosis without ketosis. Beta-hydroxy-beta-methylglutaryl-reductase, an enzyme that catalyses the rate-limiting step of cholesterol biosynthesis, beta-hydroxy-beta-methylglutaryl-CoA + 2NADPH + 2H+ → mevalonate + 2NADP+ + coenzyme A. Beta-hydroxy-beta-methylglutaryl-synthase, an enzyme in mitochondria that catalyses the reaction of acetyl-CoA with acetoacetyl-CoA and water to form beta-hydroxy-beta-methylglutaryl-CoA and coenzyme A, a step required for both ketogenesis and steroidogenesis to occur. (05 Mar 2000) |
| beta-n-acetylglucosaminylglycopeptide beta-1,4-galactosyltransferase | <enzyme> An enzyme that catalyses the transfer of galactose from udp-galactose to a specific glycoprotein receptor, 2-acetamido-2-deoxy-d-glucosyl-glycopeptide, during glycopeptide synthesis. Chemical name: UDPgalactose:N-acetyl-beta-D-glucosaminylglycopeptide beta-1,4-galactosyltransferase Registry number: EC 2.4.1.38 (12 Dec 1998) |
| beta, or beta-value | <radiobiology> Ratio of plasma kinetic pressure to magnetic-field pressure, proportional to the ratio of plasma kinetic energy density to magnetic field energy density. Beta is usually measured relative to the total, local field (loosely called beta toroidal), but sometimes the plasma pressure relative to only the poloidal component of the field (beta poloidal) or relative to some external field (like the maximum field at the magnetic coils) is more useful. There is also a normalised beta (beta_N) of interest when discussing the beta limit. (lots of help from Art Carlson with the above.) Because the cost of a reactor is strongly influenced by the strength of the magnetic field that must be provided, beta values are directly related to the economics of fusion power production. Beta is usually expressed as a percentage, with 5% generally believed to be the minimum value required for an economical fusion reactor. See: pressure, kinetic pressure, magnetic pressure, second stability. (09 Oct 1997) |
| UDP-GalNAc-beta-galactose beta 1,4-N-acetylgalactosaminyltransferase | <enzyme> Consider also EC 2.4.1.92 Registry number: EC 2.4.1.- Synonym: beta-1,4-n-acetylgalactosaminyltransferase, 4-galnactransferase, udp-n-acetylgalactosamine-beta-galactose beta 1,4-n-acetylgalactosaminyltransferase, (1-4)-n-acetyl-beta-d-galactosaminyltransferase, galnact-1 (26 Jun 1999) |
| 5 alpha-androstane-3 beta,17 beta-diol 6 alpha-hydroxylase | <enzyme> Requires NADPH, found in rat prostatic microsomes Registry number: EC 1.14.13.- Synonym: artdl 6 alpha-hydroxylase (26 Jun 1999) |