| essential amino acids | Alpha-amino acids nutritionally required by an organism and which must be supplied in its diet (i.e., cannot be synthesised by the organism) either as free amino acid or in proteins. (05 Mar 2000) |
|---|---|
| essential amino acid | <biochemistry> Those amino acids that cannot be synthesised by an organism and must therefore be present in the diet. The term is often applied anthropocentrically to those amino acids required by humans (Ileu, Leu, Lys, Met, Phe, Thr, Try, & Val), though rats need two more (Arg & His). (18 Nov 1997) |
| fatty acids, essential | Fatty acids that cannot be synthesised by the human body and must be obtained from dietary sources, e.g., linoleic acids and linolenic acids. (12 Dec 1998) |
| amino acids | Organic compounds that generally contain an amino (-nh2) and a carboxyl (-cooh) group. Twenty alpha-amino acids are the subunits which are polymerised to form proteins. (12 Dec 1998) |
| amino acids, branched-chain | Amino acids which have a branched carbon chain. (12 Dec 1998) |
| amino acids, cyclic | A class of amino acids characterised by a closed ring structure. (12 Dec 1998) |
| amino acids, peptides, and proteins | Amino acids and chains of amino acids connected by peptide linkages. (12 Dec 1998) |
| excitatory amino acids | Endogenous amino acids released by neurons as excitatory neurotransmitters. Glutamic acid is the most common excitatory neurotransmitter in the brain. Aspartic acid has been regarded as an excitatory transmitter for many years, but the extent of its role as a transmitter is unclear. (12 Dec 1998) |
| benign essential tremor | A benign tremor inherited as a dominant character; it may be a rapid oscillation resembling that seen in thyrotoxicosis, a coarse tremor during rest and inhibited by a voluntary effort, or one which appears only upon movement. Synonym: benign essential tremor, familial tremor. (05 Mar 2000) |
| drugs, essential | Drugs considered essential to meet the health needs of a population as well as to control drug costs. (world health organization action programme on essential drugs, 1994, p3) (12 Dec 1998) |
| osteolysis, essential | Syndromes of bone destruction where the cause is not obvious such as neoplasia, infection, or trauma. The destruction follows various patterns: massive (gorham disease), multicentric (hajdu-cheney syndrome, winchester syndrome), or carpal/tarsal. (12 Dec 1998) |
| Eagle's minimum essential medium | A tissue culture medium similar to Eagle's basal medium but with different amounts and a few exclusions (e.g., antibiotics and phenol red). (05 Mar 2000) |
| essential | 1. Belonging to the essence, or that which makes an object, or class of objects, what it is. "Majestic as the voice sometimes became, there was forever in it an essential character of plaintiveness." (Hawthorne) 2. Hence, really existing; existent. "Is it true, that thou art but a a name, And no essential thing?" (Webster (1623)) 3. Important in the highest degree; indispensable to the attainment of an object; indispensably necessary. "Judgment's more essential to a general Than courage." (Denham) "How to live? that is the essential question for us." (H. Spencer) 4. Containing the essence or characteristic portion of a substance, as of a plant; highly rectified; pure; hence, unmixed; as, an essential oil. "Mine own essential horror." 5. Necessary; indispensable; said of those tones which constitute a chord, in distinction from ornamental or passing tones. 6. <medicine> Idiopathic; independent of other diseases. <biology> Essential character, a class of volatile oils, extracted from plants, fruits, or flowers, having each its characteristic odour, and hot burning taste. They are used in essences, perfumery, etc, and include many varieties of compounds; as lemon oil is a terpene, oil of bitter almonds an aldehyde, oil of wintergreen an ethereal salt, etc.; called also volatile oils in distinction from the fixed or nonvolatile. Origin: Cf. F. Essentiel. See Essence. Source: Websters Dictionary (01 Mar 1998) |
| essential albuminuria | A collective term for types that are not the result of pathologic changes in the kidneys. Synonym: essential albuminuria. (05 Mar 2000) |
| essential anaemia | An obsolete term for pernicious anaemia; also used formerly for any type of anaemia of unknown mechanism. (05 Mar 2000) |