H&E Staining Flashcards
basophilic
substances that attract basic dyes, blue hematoxylin, ex: nuclei, ribosomes
acidophilic
substances that attract acidic dyes, pink eosin, ex: proteins, cytoplasm
basic dye
charge on the dye ion is positive, also known as cationic
ex: crystal violet, safranin
acidic dye
charge on the dye ion is negative, also known as anionic,
ex: orange G, picric acid
mordant
a reagent, often a metal (aluminum, tungsten, iron, chromium) used to link the stain to the tissue
lake
the combination of a dye and a mordant
hematein
oxidation product of hematoxylin, a weak anionic dye
differentiation
process by which excess stain is removed from a tissue so that only the desired element is left stained so it can easily be seen against a clear or counterstained background
progressive staining
the reaction is stopped once the desired intensity is achieved. The slide is then rinsed and blued to increase the intensity of the nuclear stain. usually for special stains
regressive staining
tissue is overstained and then decolorized with an acidic solution until only the desired element is left stained, this is typically how mordant dyes are used. typically used for hematoxylin staining
Delafield
naturally ripened by exposing to oxygen, aluminum mordant, regressive staining
Ehrlich
naturally ripened by exposing to oxygen, aluminum mordant, regressive staining
Harris
chemically oxidized with sodium iodate, aluminum mordant, progressive staining
Mayer
chemically oxidized with sodium iodate, aluminum mordant, does not contain alcohol, progressive staining
Gill
chemically oxidized with sodium iodate, aluminum mordant, progressive staining, only hematoxylin that will stain mucin, esp in goblet cells
Weigert
ferric chloride (iron) is the oxidizer and mordant, not used in routine H&E, resists acidic solutions
hematin
formalin pigment
chromogen
benzene derivatives that contain chromogens
chromophore
the chemical group that confers color in dyes
auxochrome
ionizing groups that enable dye to link firmly to tissue
MGP technique (methyl green-pyronin)
stains RNA rose using pyronin and DNA green with methyl green
giemsa
polychrome stain; a compound dye made up of different colors that should be pH 6.4 to 6.9
Feulgen reaction
demonstrates DNA but not RNA, shows red nuclei only
Bouin solution
hydrolyzes nuclei during fixation, doesn’t work with Feulgen reaction
acetic acid
makes nuclear staining more selective
Romanowsky-type stains
a combination of the basic dye methylene blue and the acidic dye eosin commonly used to differentiate leukocytes (white blood cells)
refractive index
should be near that of the tissue
refractive index
should be near that of the tissue, tissue appears more transparent as the media’s refractive index approaches that pf the tissue
cane sugar
can be added to aqueous mounting media to prevent diffusion of basic aniline dyes
cornflaking
tissue dries out before coverslipping and appears burnt or singed
pale pink cytoplasm in H&E
pH problem with the eosin; due to incomplete removal of bluing agent (too low pH) or too little acid (too high pH)
reddish brown nuclei in H&E
over ripened hematoxylin
uneven staining
paraffin was not completely removed
milky water after hydrating alcohols
xylene has been carried over, change the alcohols to correct this
slide dries out before coverslipping
glossy black nuclei, cornflaking, and brown stippling may occur
dark nuclei and blue cytoplasm in H&E
inadequate differentiation
blue-black precipitate in H&E
filter the hematoxylin to remove aluminum-hematein crystals
incomplete dehydration
microscopic water bubbles trapped under the coverslip
microscopic water bubbles trapped under the coverslip
incomplete dehydration
some parts of tissue can’t be brought into focus
mounting media on top of the coverslip
hazy blue nuclei
too much heat during processing
undo H&E
use acid alcohol
last dehydrating alcohol is very pink
contains water which carried over eosin
poor Giemsa staining
change the pH of the solution
