Stains Flashcards
(70 cards)
Derived from plants and animals; examples include Hematoxylin, Cochincal dyes, Orcein, Saffron (dried stigmata of Crocus sativus)
Natural Dyes
Hematoxylin is a natural dye obtained from the Mexican tree Hematoxylin campechianum, extracted with hot water and precipitated using urea
Hematoxylin
Hematoxylin is not a stain by itself; it requires a mordant (e.g., hematin/hematein) to be effective
Hematoxylin Staining
Natural ripening involves exposing hematoxylin to sunlight and air; takes 3-4 months; stains are Erlich’s and Delafield’s
Natural Ripening
Chemical oxidation involves oxidizing agents such as hydrogen peroxide, mercuric oxide, potassium permanganate, sodium perborate, sodium iodate; stains are Mayers, Harris (artificial ripening)
Artificial Ripening
Derived from plants and animals; examples include Hematoxylin, Cochincal dyes, Orcein, Saffron (dried stigmata of Crocus sativus)
Natural Dyes
Hematoxylin is a natural dye obtained from the Mexican tree ____ extracted with hot water and precipitated using urea
Hematoxylin campechianum
Hematoxylin is not a stain by itself; it requires a mordant to be effective; active coloring agent is
hematin/hematein
Natural ripening involves exposing hematoxylin to; takes 3-4 months; stains are Erlich’s and Delafield’s
sunlight and air
Chemical oxidation involves oxidizing agents such as hydrogen peroxide, mercuric oxide, potassium permanganate, sodium perborate, sodium iodate; stains are Mayers, Harris
Artificial Ripening
Extracted from Coccus cacti (female bug); Cochineal with alum gives Carmine dye; used as chromatin and nuclear stain for fresh and smear preparations
Cochineal Dyes
Cochineal with picric acid forms Picrocarmine, used as a neuropathologic stain
Picrocarmine
Cochineal aluminum chloride provides the best Carmine; used for demonstration of glycogen
Best Carmine
Vegetable dye extracted from lichens; used for staining elastic fibers (skin); colorless, treated with ammonia, exposed to air to produce blue/violet color; also used in litmus paper as a pH indicator
Orcein
Synthetic dyes, also known as coal tar dyes or aniline dyes, are derived from hydrocarbons such as benzene
Synthetic Dyes
Substances with definite atomic groupings that produce visible color but not permanent; simple benzene compounds containing chromophores are called
Chromogens
Substances added to a chromogen to alter its property, changing its shade, enabling it to form salts with another compound and retain color in tissue
Auxochrome
Synthetic dyes are composed of chromophore and auxochrome, which together impart permanent color to tissues
Synthetic Dyes Composition
Coloring substance found in the acid component; Basic cell structures have an affinity for acid dye ions and are called acidophilic; examples include picric acid, eosin
Acid Dyes
The coloring substance is found in the basic component that combines with the acid radical; Acidic structures have an affinity for basic dyes and are called basophilic; example: methylene blue
Basic Dyes
Formed by combining aqueous solutions of acid and basic dyes; stains cytoplasm and nucleus simultaneously and differentially; examples include Wright’s and Giemsa
Romanowsky Dyes
Hematoxylin (pH 2.5-2.9) - Most commonly used for histologic studies; combined with mordants such as alum or iron to form the dye-mordant tissue complex; filter the stain prior to use to remove metallic sheen (especially in Harris Hematoxylin)
Hematoxylin Staining
Aluminum Hematoxylin: Routinely used in H and E staining with alum as the mordant; initially stains the nuclei reddish and forms blue lakes after the blueing step; blueing agent is pH 8 (2 minutes); examples: Scott’s tap water, ammonia H2O; for progressive and regressive staining
Aluminum Hematoxylin
Harris Hematoxylin: Routinely used in nuclear staining; ripened with mercuric oxide; used in cytology (e.g., Pap’s smear, staining of sex chromosomes); regressive staining method; addition of glacial acetic acid gives precise nuclear staining
Harris Hematoxylin
