| dl- | <prefix> Prefix (in small capital letters) denoting a substance consisting of equal quantities of the two enantiomorphs, d and l; replaces the older dl-(in lower case italics) as a more exact definition of structure. (05 Mar 2000) |
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| dl-hyoscyamine | <drug> A toxic alkaloid extracted from belladonna and other members of thenightshade family, it is typically used to dilate the eye and to stopmuscular spasms. Pharmacologic action: Parasympatholytic. Competitive blockade of acetylcholine at muscarinic receptors. Increases sinus node automaticity and AV conduction. Uses: Treat bradycardia, asystole, and AV block Dose: 0.5 - 1.0 mg for bradycardia every 3 - 5 min to a total dose of 0.04 mg/kg. Doses smaller than 0.5 mg can cause a paradoxical bradycardia due to sympathomimetic effects Typically 3 mg is adequate to completely block vagal effects Atropine is well absorbed via endotracheal route - administer 1-2 mg diluted in 10 mL sterile water or normal saline. Potential complications: 1. Tachyarrhythmias 2. Exacerbation of myocardial ischemia 3. Low dose may cause paradoxical bradycardia 4. Dry mouth, urinary retention, flushed and hot skin 5. Crosses blood-brain barrier which can cause delirium Note: The denervated heart will not respond to atropine. (15 Mar 2000) |
| dl-narcotine | <chemistry> An alkaloid existing in small quantities in opium. Origin: Gr. Gignwskein to know + E. Opium?. Source: Websters Dictionary (01 Mar 1998) |
| DLVO theory | <cell biology> Theory of colloid flocculation advanced independently by Derjaguin & Landau and by Vervey & Overbeek and subsequently applied to cell adhesion. There exist distances (primary and secondary minima) at which the forces of attraction exceed those of electrostatic repulsion, an adhesion will thus be formed. For cells there is quite good correlation between the calculated separations of primary and secondary minima and the cell separations in tight junctions (1-2nm) and more general cell cell appositions (12-20nm) respectively, although it is clear that other factors (particularly cell adhesion molecules) also play an important part. (18 Nov 1997) |