| diphtheritis | <infectious disease> An acute infectious disease caused by toxigenic strains of Corynebacterium diphtheriae, acquired by contact with an infected person or a carrier of the disease, which is usually confined to the upper respiratory tract. It is characterised by the formation of a tough membrane (false membrane or pseudomembrane) attached firmly to the underlying tissue that will bleed if forcibly removed. In the most serious infections the membrane begins in the tonsillar (faucial) area on one tonsil and may spread to involve the other tonsil, uvula, soft palate and pharyngeal wall, from where it may extend to the larynx, trachea and bronchial tree and may cause bronchial obstruction and death by hypoxia. Diphtheria also occurs in a cutaneous form and may rarely involve the eyes, middle ear, buccal mucosa, genitalia and umbilical stump, usually secondarily. Systemic effects, chiefly myocarditis and peripheral neuritis, are caused by the exotoxin produced by C. Diphtheriae. Synonym: Bretonneau's angina. Origin: Gr. Diphthera = leather (18 Nov 1997) |
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| diphtheroid | 1. One of a group of local infections suggesting diphtheria, but caused by microorganisms other than Corynebacterium diphtheriae. Synonym: Epstein's disease, false diphtheria, pseudodiphtheria. 2. Any microorganism resembling Corynebacterium diphtheriae. Origin: diphtheria + G. Eidos, resemblance (05 Mar 2000) |
| diphtherotoxin | The toxin of diphtheria. (05 Mar 2000) |
| diphthine methyltransferase | <enzyme> Catalyses the transfer of three methyl groups from 5-adenosylmethionine to 2-(3-carboxy-3-aminopropyl)histidine (cg-1 precursor) to the amino group on carbon 3 of the side chain to form diphthine, a post-translational modified histidine Registry number: EC 2.1.1.- Synonym: met-ef-2 methyltransferase (26 Jun 1999) |
| diphthong | Origin: L. Diphthongus, Gr.; = twice + voice, sound, fr. To utter a sound: cf. F. Diphthongue] A coalition or union of two vowel sounds pronounced in one syllable; as, ou in out, oi in noise; called a proper diphthong. A vowel digraph; a union of two vowels in the same syllable, only one of them being sounded; as, ai in rain, eo in people; called an improper diphthong. Source: Websters Dictionary (01 Mar 1998) |