negative staining


Also found in: Dictionary, Thesaurus, Encyclopedia.

negative staining

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.

staining

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.

chromosomal staining
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.
negative staining
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.
Enlarge picture
Negatively stained virus particles of infectious bursal disease virus. By permission from Fenner F, Gibbs EPJ, Horzinek MC, Studdert MJ, Murphy FA, Veterinary Virology, Academic Press, 1999
radiograph staining
may be yellow or brown stains due to inadequate rinsing, or doubly refracting exhibiting different colors depending on angle of viewing.
References in periodicals archive ?
Note positive staining in nonneoplastic colonic mucosa (A) but negative staining in nonneoplastic small intestinal mucosa (B; original magnifications X40 [A] and X100 [B]).
2) to compare the sensitivity of negative staining of Heine with modified negative staining method.
In terms of diagnosis of malignancy, the combination of cytology and positive staining for CEA as well as negative staining for CAL reached a diagnosis in 29 of 30 metastatic adenocarcinoma cases, with 97% sensitivity, 100% specificity and 98% accuracy.
Knob-tike protrusions found on the surfaces of SVs, apparent after negative staining, have previously been regarded as the vacuolar ATP-dependent proton pump (V-ATPase) (Wilkens et al.
3] positive sites on the long arm, probably indicating AgNOR, while with the fluorochrome DAPI these regions showed negative staining and were therefore rich in GC bases.
Histochemical stains showed negative staining for PAS with diastase predigestion (dPAS), and in a few epithelial cases, mucicarmine stained focal areas.
Kedersha turned to negative staining, a microscopy method as simple as it is messy.
NanoImaging offers a variety of services, from visual inspection and statistical characterization to sophisticated 3D reconstruction and antibody/labeling experiments, using TEM procedures that range from conventional negative staining to advanced cryo techniques with automated image acquisition and analysis.
Myoepithelial (MEP) Markers MEP Markers Cellular MEP Stromal Vessels Localization Cells Myofibroblasts p63 Nuclear +++ - - Calponin Cytoplasm +++ + ++ SMMHC Cytoplasm +++ + ++ SMA Cytoplasm +++ +++ +++ Basal-type Cytoplasm +++ - - CKs (a) and membrane Abbreviations: CKs, cytokeratins;SMA, smooth muscle actin; SMMHC, smooth muscle myosin heavy chain; +, weak, positive staining; ++, medium, positive staining; +++, strong, positive staining; -, negative staining.
Immunohistochemistry revealed positive staining with S-100 protein, Vimentin, smooth muscle actin (SMA) and negative staining for Estrogen and Progesterone Receptors.
Table 1: Criteria for Immunohistochemical Analysis of Percentage of Cells (6) Expressing the Marker Negative Staining <1% tumour cells show positive staining Weak Positive Staining 1-10% of tumour cells show weak positive staining Strong Positive Staining >10% of tumour cells show positive staining Expression of CEA in Comparison with Other Markers VIM+ VIM- ER+ ER- PR+ PR- CEA+ 1 16 1 16 2 15 CEA- 10 3 9 4 6 7 Expression of Vimentin in Comparison with Other Markers CEA+ CEA- ER+ ER- PR+ PR- VIM+ 1 10 10 1 6 5 VIM- 16 3 0 19 1 18 Table 2: Association of Tumour Grade with CEA Expression Grade Positive Negative Total Well Differentiated 3 11 14 Moderately Differentiated 11 1 12 Poorly Differentiated 3 1 4 Total 17 13 30 Chi-Square Test p value 0.