negative staining


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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 ?
UC followed by negative staining with uranyl acetate was applied to 531 urine samples.
In the SmCC microarray, all cases (n = 35) were identified by a strong positive staining for TTF-1 and negative staining for napsin A, DG3 + CK5, and P40, providing a negative predictive value of 100% for the DG3 + CK5/napsin A cocktail.
adsorption followed by negative staining, is used for preparation (Figure 4A).
Negative staining with a drop of 10 g/L uranyl acetate in distilled water was performed.
A: Photomicrograph showing bland spindle cells arranged in fascicles (H&E, x20); B: Immunohistochemical stain showing rare single cell positivity for AFP (x60); C: Immunohistochemical stain showing negative staining for cam 5.
The flagella preparation was rich in flagellar filaments as determined by negative staining and electron microscopy (Figure 2C).
Features seen within PTAT that create difficulty in distinguishing it from prostatic acinar adenocarcinoma include the following: (1) crowded and sometimes disorganized patterns of growth, (2) relatively high nuclear to cytoplasmic ratio with slightly enlarged nuclei, (3) straight luminal borders in some glands, (4) the presence of visible but small nucleoli, (5) negative staining of some glands for basal cells markers, and (6) positive staining of some glands for racemase (Figures 1, A through F, and 2, A through F).
Immunohistochemical staining of tumour tissue was negative for prostate-specific antigen (PSA) and prostate-specific acid phosphatase, strongly positive for cytokeratin (CK) 7/20/ carcinoembryonic antigen (CEA), strong nuclear positive for caudal-related homeobox 2 (CDX2) and negative staining for CK5/6.
Supernatants of Vero cells infected with the EBN-associated virus were concentrated 100-fold by ultracentrifugation and visualized by negative staining with 2% uranyl acetate.
For FLI1, positive staining in greater than or equal to 50% of tumor nuclei was scored as ++, less than 50% was scored as +, and negative staining was scored as -.
34) Data in the Tables are presented as the number of positive staining tumors versus the number of negative staining tumors in the same tumor type for Nap-A versus TTF-1 or as the number of positive staining tumors versus the number of negative staining tumors in different tumor types for Nap-A or TTF-1 alone.
Immunohistochemical studies revealed diffuse strong reactivity for Melan-A (Figure, C), HMB-45 (Figure, D), smooth muscle actin (Figure, E), vimentin, and negative staining for inhibin, synaptophysin, chromogranin, calretinin, and AE1/3.