Category: D

An animal that is active during the day and sleeps at night.  

The outermost, toughest, and most fibrous of the three membranes (meninges) covering the brain and spinal cord; called also pachymeninx. The outermost layer of the meninges that cover the brain and spinal cord. The subdural space lies below it and separates it from the arachnoid membrane. A tough, fibrous membrane covering the brain. The thicker…

Diminished or failed response of an organism, disease or tissue to the intended effectiveness of a chemical or drug. It should be differentiated from drug tolerance which is the progressive diminution of the susceptibility of a human or animal to the effects of a drug, as a result of continued administration. Having a (often acquired)…

The action of a drug that may affect the activity, metabolism, or toxicity of another drug. The effects of two or more drugs taken concomitantly, producing an alteration in the usual effects of either drug taken alone. The interacting drugs may have a potentiating or additive effect and produce side effects. An example of drug…

The molecular designing of drugs for specific purposes (such as DNA-binding, enzyme inhibition, anti-cancer efficacy, etc.) based on knowledge of molecular properties such as activity of functional groups, molecular geometry, and electronic structure, and also on information cataloged on analogous molecules. Drug design is generally computer-assisted molecular modeling and does not include pharmacokinetics, dosage analysis,…

Systems of administering drugs through controlled delivery so that an optimum amount reaches the target site. Drug delivery systems encompass the carrier, route, and target.  

A state of internal activity of an organism that is a necessary condition before a given stimulus will elicit a class of responses; e.g., a certain level of hunger (drive) must be present before food will elicit an eating response. Basic urge, instinct, motivation; a term used to avoid confusion with the more purely biological…

In genetics, the full phenotypic expression of a gene in both heterozygotes and homozygotes. In psychological terms, a predisposition to play a prominent or controlling role when interacting with others. In neurology, the (normal) tendency of one-half of the brain to be more important than the other in mediating various functions (cerebral dominance). In genetics,…

A reagent commonly used in biochemical studies as a protective agent to prevent the oxidation of SH (thiol) groups and for reducing disulphides to dithiols.