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a technique in which an electron-dense substance is mixed with a specimen, resulting in an electron microscopic image in which the specimen appears translucent against an opaque or dark background.
1. artificial coloration of a substance to facilitate examination of tissues, microorganisms or other cells under the microscope. For various techniques, see under stain.
2. marring the appearance.
blood is collected in a highly aseptic manner and placed in tissue culture medium containing a stimulant to cell division. The leukocytes are collected, killed with a cytotoxic agent, enlarged by osmosis in a hypotonic liquid, placed on slides, fixed and stained.
a procedure visualizing specimens by either light or electron microscopy. In light microscopy, India ink which blocks the transmission of light is used as a negative stain to detect bacterial capsules. In electron microscopy, electron-dense salts such as sodium phosphotungstate are used in the examination of particles particularly viruses.
may be yellow or brown stains due to inadequate rinsing, or doubly refracting exhibiting different colors depending on angle of viewing.