| W | Symbol for tungsten; watt; tryptophan. (05 Mar 2000) |
|---|---|
| w chromosome | <genetics> A sex chromosome found in all birds and certain other animals where the female is the heterogametic sex. The W chromosome causes the individual to become female in bird species. It is part of the WZ set of sex chromosomes, where the female has one W chromosome and one Z chromosome, and the male has two Z chromosomes. (09 Oct 1997) |
| W factor | <biochemistry> A prosthetic group for carboxylase enzymes. Important in fatty acid biosynthesis and catabolism and has found widespread use as a covalent label for macromolecules which may then be detected by high affinity binding of labelled avidin or streptavidin. Essential growth factor for many cells. (18 Nov 1997) |
| W locus | <molecular biology> Mouse coat colour locus, equivalent to the kit proto-oncogene, that encodes a receptor tyrosine kinase essential for development of haemopoietic and germ cells. (18 Nov 1997) |
| W procedure | Surgery to prevent the contracture of a straight-line scar; the edges of the wound are trimmed in the shape of a W, or a series of W's, and closed in a zig-zag manner. Synonym: W procedure. (05 Mar 2000) |
| W rays | Those between ultraviolet and X-ray's. Synonym: W rays. (05 Mar 2000) |
| W-arch | A fixed maxillary expansion device attached to the lingual part of the molars, with either bilateral or unilateral extension arms. (05 Mar 2000) |
| W-plasty | Surgery to prevent the contracture of a straight-line scar; the edges of the wound are trimmed in the shape of a W, or a series of W's, and closed in a zig-zag manner. Synonym: W procedure. (05 Mar 2000) |
| waag | <zoology> A monkey of the upper Nile and Abyssinia (Cercopithecus griseoviridis), having the upper parts dull green, the lower parts white, the hands, ears, and face black. It was known to the ancient Egyptians. Synonym: tota. Origin: Cf. F. Grivet. Source: Websters Dictionary (01 Mar 1998) |
| Waage, P | <person> Norwegian chemist, 1833-1900. See: Guldberg-Waage law. (05 Mar 2000) |
| waahoo | <botany> The burning bush; said to be called after a quack medicine made from it. Source: Websters Dictionary (01 Mar 1998) |
| Waaler, Erik | <person> 20th century Norwegian biologist. See: Rose-Waaler test. (05 Mar 2000) |
| Waardenburg syndrome | <syndrome> Rare, autosomal dominant disease with variable penetrance and several known clinical types. Clinical features include depigmentation of the skin and hair with a white forelock, congenital cochlear deafness, heterochromia iridis or hypochromia iridis, medial eyebrow hyperplasia, hypertrophy of the nasal root producing increased width of the root of the nose, dystopia canthorum, lateral dystopia of medial canthi and lacrimal puncta and synophrys. The underlying cause may be defective development of the neural crest (neurocristopathy). Waardenburg's syndrome may be closely related to piebaldism. Klein-waardenburg syndrome refers to a disorder that also includes upper limb abnormalities. Inheritance: audosomal dominant. (21 Jun 2000) |
| Waardenburg, Petrus Johannes | <person> Dutch ophthalmologist, 1886-1979. See: Waardenburg syndrome. (05 Mar 2000) |
| Wachendorf's membrane | Remnants of the central portion of the anterior layer of the iris stroma (the iridopupillary lamina) which occludes the pupil in foetal life, and normally atrophies about the seventh month of gestation. Persistent strands usually stretch across the pupil from one iris collarette to the other, without touching the pupillary margin. Failure to regress is a rare cause of congenital blindness. Synonym: membrana pupillaris, Wachendorf's membrane. (05 Mar 2000) |