| differential gene expression | Gene expression that responds to signals or triggers; a means of gene regulation; e.g., effects of certain hormones on protein biosynthesis. (05 Mar 2000) |
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| differential growth | Different rates of growth in associated tissues or structures; used especially in embryology when the differences in growth rates result in changing the original proportions or relations. (05 Mar 2000) |
| differential interference contrast | <technique> A mode of contrast generation in microscopy that yields an image with a shadow relief. The relief reflects the gradient of optical path difference. Differential Interference Contrast, which is a form of interferenc microscopy that uses polarizing beam splitters, can be of the Smith or Nomarski type. Acronym: DIC (05 Aug 1998) |
| differential manometer | Any device that indicates the difference in pressure between two fluids, regardless of any changes in their absolute pressures. Mercurial manometer, an manometer in which the varying pressures are shown by differences of elevation in a column of mercury. (05 Mar 2000) |
| differential medium | A medium which is used to differentiate different types of microorganisms based on their different colours or colony shapes. Examples of differential media are: Macconkey's agar and SS agar. (09 Oct 1997) |
| differential renal function test | A study performed to determine various functional parameters of one kidney compared to the contralateral kidney; ureteral catheters are inserted at cystoscopy into the ureter or renal pelvis bilaterally, and simultaneous measurements are made of urine flow rate, insulin, or PAH (if infused), endogenous creatinine, or various urinary solutes. Synonym: differential renal function test, split renal function test. (05 Mar 2000) |
| differential screening | Process in development of a multicellular organism by which cells become specialised for particular functions. Requires that there is selective expression of portions of the genome, the fully differentiated state may be preceded by a stage in which the cell is already programmed for differentiation but is not yet expressing the characteristic phenotype determination. (18 Nov 1997) |
| differential spinal anaesthesia | A form of diagnostic spinal anaesthesia producing blockade of different types of nerves in the subarachnoid space, based upon their differences in sensitivity to local anaesthetics; also observed during surgical spinal anaesthesia. (05 Mar 2000) |
| differential stain | <technique> A dye used to colour one portion of a tissue or cell which remained unaffected when the other part was stained by a dye of different colour. Synonym: differential stain. (05 Mar 2000) |
| differential thermal analysis | Technique by which phase transitions of chemical reactions can be followed by observation of the heat absorbed or liberated. (12 Dec 1998) |
| differential thermometer | <instrument, physics> An instrument for indicating changes of temperature without indicating the degree of heat by which it is affected; especially, an instrument contrived by Count Rumford which, as modified by Professor Leslie, was afterward called the differential thermometer. Origin: Thermo- + -scope. Source: Websters Dictionary (01 Mar 1998) |
| differential threshold | The smallest difference which can be discriminated between two stimuli or one which is barely above the threshold. (12 Dec 1998) |
| differential ureteral catheterization test | A study performed to determine various functional parameters of one kidney compared to the contralateral kidney; ureteral catheters are inserted at cystoscopy into the ureter or renal pelvis bilaterally, and simultaneous measurements are made of urine flow rate, insulin, or PAH (if infused), endogenous creatinine, or various urinary solutes. Synonym: differential renal function test, split renal function test. (05 Mar 2000) |
| differential white blood count | An estimate of the percentage of white blood cell types which make up the total white blood cell count. (05 Mar 2000) |
| differentiate | The process cells undergo as they mature into normal cells. Differentiated cells have distinctive characteristics, perform specific functions and are less likely to divide. See: dedifferentiate, undifferentiated. (16 Dec 1997) |