| alpha cells of pancreas | Cell's of the islets of Langerhans that secrete glucagon. (05 Mar 2000) |
|---|---|
| alpha chain disease | A vague or indefinite term; could be used for alpha-heavy-chain disease (a lymphoplasma cell proliferative disease usually seen in Mediterranean men, characterised by intestinal involvement with steatorrhoea, often progressive with fatal outcome) or a thalassaemia (a genetic abnormality in the alpha globin chain of haemoglobin). (05 Mar 2000) |
| alpha channeling | <radiobiology> Term for an idea (so far theoretical) in magnetic confinement fusion, the idea is that plasma waves can be used to control the alpha particles produced in a fusion reactor, to transfer their energy directly to fuel ions, and to help push them out of the plasma. This could potentially help to substantially improve the power output capabilities of fusion plasmas. (09 Oct 1997) |
| alpha-chloralose | A conjugate of chloral and glucose used as an anaesthetic in laboratory animals; it does not depress cardiovascular reflexes as much as most other anaesthetic agents. (05 Mar 2000) |
| alpha-chlorohydrin | <chemical> 3-chloro-1,2-propanediol. A chlorinated propanediol compound that has shown anti-fertility activity in males and has been used as a chemosterilant in rodents. Pharmacological action: chemosterilants, contraceptive agents, male. Chemical name: 1,2-Propanediol, 3-chloro- (12 Dec 1998) |
| alpha-chymotrypsin-induced glaucoma | Transient secondary glaucoma following the use of alpha-chymotrypsin in cataract extraction. (05 Mar 2000) |
| alpha-cortol | 5b-Pregnane-3a,11b,17,20a,21-pentaol; the 5b enantiomer of alpha-allocortol;a reduction product of cortisone, present in the urine, differing from cortisone in that the three keto groups are reduced to hydroxyls. (05 Mar 2000) |
| alpha-cortolone | 3a,17a,20a,21-Tetrahydroxy-5b-pregnane-11-one;the 5b enantiomer of alpha-allocortolone; a reduction product of cortisone, present in the urine, differing from cortisone in that two of the keto groups (at positions 3 and 20) are reduced to hydroxyls. (05 Mar 2000) |
| alpha-d-galactosidase | <enzyme> An enzyme catalyzing the hydrolysis of alpha-d-galactosides to release free d-galactose. A deficiency of type A alpha-d-galactosidase is associated with Fabry's disease. Synonym: melibiase. (05 Mar 2000) |
| alpha-d-glucosidase | A glucohydrolase removing terminal nonreducing 1,4-linked alpha-glucose residues by hydrolysis, yielding alpha-glucose; a deficiency of the lysosomal enzyme is associated with glycogen storage disease type II. There are at least five isozymes of maltase. Synonym: glucoinvertase. (05 Mar 2000) |
| alpha-D-mannose-beta-1,2-N-acetylglucosaminyltransferase | <enzyme> Absolute specificity for terminal branched mannosyl residues of glycolipids Registry number: EC 2.4.1.- Synonym: udpgnac-1,2-magtransferase (26 Jun 1999) |
| alpha-D-xylosidase | <enzyme> Highly specific for 4-nitrophenyl alpha-d-xylopyranoside and isoprimeverose; can also split off the alpha-d-xylopyranosyl residue on the non-reducing terminal of the backbone of certain oligoxyloglucans Registry number: EC 3.2.1.- Synonym: alpha-d-xylosidase I, alpha-d-xylosidase II (26 Jun 1999) |
| alpha emission | <physics> Form of nuclear decay where the nucleus emits an alpha particle (see entry below). (09 Oct 1997) |
| alpha-endorphin | <chemical> An endogenous opioid peptide derived from the pro-opiomelanocortin precursor. It differs from gamma-endorphin by one amino acid. Chemical name: alpha-Endorphin (12 Dec 1998) |
| alpha error | The statistical error (said to be of the first kind or type I) made in testing an hypothesis when it is concluded that a result is positive when it really is not. Alpha error is often referred to as a false positive. (12 Dec 1998) |