| metabolic clearance rate | Volume of biological fluid completely cleared of drug metabolites as measured in unit time. Elimination occurs as a result of metabolic processes in the kidney, liver, saliva, sweat, intestine, heart, brain, or other site. (12 Dec 1998) |
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| clearance | 1. The process of clearing. 2. <physiology> The rate at which a substance is removed from the blood. (18 Nov 1997) |
| mucociliary clearance | Rate of ciliary and secretory activity of the respiratory submucosal glands. It is a non-specific host defense mechanism, measurable in vivo by mucus transfer, ciliary beat frequency, and clearance of radioactive tracers. (12 Dec 1998) |
| creatinine clearance | Measurement of the clearance of endogenous creatinine, used for evaluating the glomerular filtration rate (GFR). (05 Mar 2000) |
| steroid metabolic clearance rate | A measure of the rate of metabolism of a given steroid within the body, usually expressed as liters of body fluid that contain the amount of steroid metabolised per day. (05 Mar 2000) |
| interocclusal clearance | The space between the occluding surfaces of the maxillary and mandibular teeth when the mandible is in physiologic resting position. Synonym: interocclusal clearance, interocclusal distance, interocclusal gap, interocclusal rest space. (05 Mar 2000) |
| inulin clearance | An accurate measure of the rate of filtration through the renal glomeruli, because inulin filters freely with water and is neither excreted nor reabsorbed through tubule walls. Inulin is not a normal constituent of plasma and must be infused continously to maintain a steady plasma concentration and a steady rate of urinary excretion during the measurement. Inulin clearance in a normal adult person is about 120 ml/min (range 100-150) per 1.73 m2 body surface area. (05 Mar 2000) |
| isotope clearance | The rate at which an isotope is removed (usually by blood flow) from a tissue or organ such as the brain. (05 Mar 2000) |
| occlusal clearance | A condition in which the opposing occlusal surfaces may glide over one another without any interfering projection. (05 Mar 2000) |
| osmolal clearance | The volume of urine that would be excreted per minute if the urinary solutes were accompanied by just enough water to make the urine isosmotic with plasma, i.e., so that the solute excretion did not change the osmolality of body fluids. To calculate it, the volume of urine excreted per minute is multiplied by the urinary osmolality (usually measured by freezing point depression) and divided by the plasma osmolality. Osmolal clearance is less than actual urine flow when urine is hyposmotic and exceeds it when urine is hyperosmotic. (05 Mar 2000) |
| endogenous creatinine clearance | A term distinguishing measurements based on the creatinine normally present in plasma; since no infusion is necessary, an average value may be obtained by collecting urine for a long period, e.g., 24 hours. (05 Mar 2000) |
| exogenous creatinine clearance | A term distinguishing measurements based on infusing creatinine intravenously to raise its plasma concentration and facilitate its accurate chemical determination. (05 Mar 2000) |
| free water clearance | The amount of water excreted in the urine beyond that which would accompany the excreted solutes if the urine were isosmotic with plasma; it represents the loss of body water in excess of solute tending to raise body osmolality and making urine hyposmotic. Unlike other clearance's, it is calculated by subtracting the osmolal clearance from the actual volume of urine excreted per minute. A negative value for free water clearance represents the amount of water that the body has reclaimed from isosmotic tubule fluid to make the urine hyperosmotic and to lower body osmolality. (05 Mar 2000) |
| Abbe test plate | <equipment> A long, wedge-shaped coverslip about 0.20 mm thick at one end and 0.10 to 0.12 mm at the other end coated chemically with a silver film on which are ruled horizontal lines. at each variation in thickness of 0.01 mm there are vertical lines. By means of oblique illumination and by focusing on different portions of the plate, it is possible to determine the optimum coverslip thickness for any objective and also, for microscopes with drawtubes, the tube length for best objective performance. The approximate freedom from spherical and chromatic aberrations can also be estimated. Small isolated bits of silver near the edges of the lines form good objects for the star test (05 Aug 1998) |
| acetone test | A test for ketonuria; the suspected urine is shaken up with a few drops of sodium nitroprusside, and strong ammonia water is then gently poured over the mixture; if acetone is present, a magenta ring forms at the line of contact; tablets containing sodium nitroprusside and alkali are now more commonly used. (05 Mar 2000) |