| interference microscopy | <procedure> Although all image formation depends on interference, the term is generally restricted to systems in which contrast comes from the recombination of a reference beam with light that has been retarded by passing through the object. Because the phase retardation is a consequence of the difference in refractive index between specimen and medium and because the the refractive increment is almost the same for all biological molecules, it is possible to measure the amount of dry mass per unit area of the specimen by measuring the phase retardation. Quantification of the phase retardation is usually done by using a compensator to reduce the bright object to darkness (see Senarmont and Ehrlinghaus compensators). Two major optical systems have been used the Jamin Lebedeff system and the Mach Zehnder system. These instruments are often referred to as interferometers, since they are designed for measuring phase retardation. Although their use has passed out of fashion, it may be that they will be employed more frequently in future in conjunction with image analysing systems. (18 Nov 1997) |
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| interference reflection microscopy | <procedure> An optical technique for detecting the topography of the side of a cell in contact with a planar substrate and for providing information on the separation of the plasmalemma from the substrate. Interference between the reflections from the substrate medium interface and the reflections from the plasmalemma medium interface generate the image. (18 Nov 1997) |
| abnormalities, drug-induced | Congenital abnormalities caused by medicinal substances or drugs of abuse given to or taken by the mother, or to which she is inadvertently exposed during the manufacture of such substances. The concept excludes abnormalities resulting from exposure to non-medicinal chemicals in the environment. (12 Dec 1998) |
| activity, drug | A measure of the physiological response a drug produces in the body. A less active drug produces less response (and visa versa). (12 Dec 1998) |
| addictive drug | Any drug that creates a certain degree of euphoria and has a strong potential for addiction. (05 Mar 2000) |
| adverse drug reaction reporting systems | Systems developed for collecting reports from government agencies, manufacturers, hospitals, physicians, and other sources on adverse drug reactions. (12 Dec 1998) |
| akathisia, drug-induced | Motor restlessness with sensations of quivering and an urge to move about constantly resulting from the use of certain drugs, such as neuroleptic drugs, which affect the extrapyramidal region of the brain. This differs from dyskinesia, drug-induced in that long-term antipsychotic drug exposure is significantly correlated with the increased prevalence of akathisia while there is no such correlation with dyskinesia. The primary observable distinction between tardive akathisia and dyskinesia appears to be in the repetitive, stereotypy of the dyskinesic movements (lip smacking, for example), while akathisia is associated with anxiety, restlessness, and agitation (psychomotor agitation). (12 Dec 1998) |
| antineoplastic drug | A drug that stops or slows the maturation and spread of tumour cells (benign or malignant). (09 Oct 1997) |
| maintenance drug therapy | In chemotherapy, systematic dosage at a level that maintains protection against exacerbation. (05 Mar 2000) |
| rational drug design | <pharmacology> Modeling the molecular structure of the target of a drug, for example, an antigen, and then designing a drug that will attack it. (17 Dec 1997) |
| receptors, drug | Proteins that bind specific drugs with high affinity and trigger intracellular changes influencing the behaviour of cells. Drug receptors are generally thought to be receptors for some endogenous substance not otherwise specified. (12 Dec 1998) |
| recreational drug | A controlled substance taken for non-medical purposes. Street drugs comprise various amphetamines, anaesthetics, barbiturates, opiates, and psychoactive drugs, and many are derived from natural sources (e.g., the plants Papaver somniferum, Cannibis sativa, Amanita pantherina, Lophophora williamsii). Slang names include acid (lysergic acid diethylamide), angel dust (phencyclidine), coke (cocaine), downers (barbiturates), grass (marijuana), hash (concentrated tetrahydrocannibinol), magic mushrooms (psilocybin), mescaline (peyote), speed (amphetamines). During the 1980s, a new class of "designer drugs" arose, mostly analogs of psychoactive substances intended to escape regulation under the Controlled Substances Act. Also, crack cocaine, a potent, smokable form of cocaine, emerged as a major public health problem. In the U.S. Illicit use of drugs such as cocaine, marijuana, and heroin historically has occurred in cycles. Synonym: recreational drug. (05 Mar 2000) |
| peak plasma drug concentration | <pharmacology> The highest level of drug that can be obtained in the blood usually following multiple doses. (09 Oct 1997) |
| chemotherapy drug sensitivity test | <investigation> A test to assess a cancerous tissue's response and vulnerability to chemotherapy drugs. This test can help predict a patients response to treatment and suggest which drugs may be useful. (16 Dec 1997) |
| metabolic detoxication, drug | Reduction of pharmacologic activity or toxicity of a drug or other foreign substance by a living system, usually by enzymatic action. It includes those metabolic transformations that make the substance more soluble for faster renal excretion. (12 Dec 1998) |