METHODS OF STAINING Flashcards
It is the basis of histochemistry; it is accomplished by controlled, specific chemical reactions designed to give a final color(staining) ate the site/location of the structure of the substances in thee cells or tissues
Specific Staining
Examples of Specific Staining
- Perl’s Prussian Blue reaction - hemosiderin
- Periodic Acid Schiff technique - polysaccharide
The staining of tissue by means of simple alcoholic/aqueous solution of the dye
Simple Staining/Direct Staining
Example of Simple/Direct Staining
Methylene blue and Eosin
The action of the dye is intensified by some other agents
Indirect staining
Substance which when taken up by tissue, helps make the in return serving as a link or bridge to make the staining reaction possible
Mordant
Combines with a dye forming a colored “lake” which combines with tissue to form an insoluble “tissue-mordant-dye complex”
Mordant
An integral part of the staining reaction itself, without which, no staining could possible occur
Mordant
Examples of Mordant
- Potassium Alum with Hematoxylin in Ehrlich’s hematoxylin
- Iron in Weigert’s hematoxylin
Chemical substances that does not participate but merely increases or heightens the color intensity, selectively and crispness of the stain
Accentuator
Differ from mordants in that they do not bind or link the tissue to the dye
Accentuator
Examples of Accentuator
- Potassium hydroxide (KOH) in Loeffler’s Methylene blue
- Phenol in Carbol thionine and Carbol fuchsin
Staining is continued in a definite sequence until the desired intensity of coloring of the different tissue elements is attained
Progressive staining
No washing/differentiation/decolorization in between is required solely relies on the selective affinity of dyes for different cellular elements
Progressive staining
Example of Progressive staining
Any stain is possible as long as no differentiation is done
Tissues are overstained and the excess dye is then removed until the desired intensity is obtained
Regressive staining
What are the two principles of Regressive staining?
- Overstaining
- Washing/Differentiation/Decolorization
Examples of Regressive staining
- Acid Fast Stain
- Gram staining
Metachromatic staining is also known as
Metachromasia
Entails the use of the specific dyes that stains tissues with a color that is different from that of the stain color itself
Metachromatic staining
Metachromatic staining is particularly employed for staining of:
(CECAM)
1. Cartilage
2. Epithelial mucin
3. Connective tissue
4. Amyloid
5. Mast cell granules
basic dye belonging to Thizine and Triphenylmethane groups
Metachromatic dye
Example of Metachromatic stain
Cresyl blue for reticulocytes
The application of a different color or stain to provide contrast and background to the staining of the structural components to be demonstrated
Counterstaining
Example of counterstain
Eosin - for the cytoplasm
Selective staining of living cell constituents, demonstrating cytoplasmic structures by phagocytosis of the dye particle (Cytoplasmic Phagocytosis)
Vital Staining
The __________ of the living cell is resistant to vital stains, and therefore is not demonstrated
nucleus
Examples of Vital Staining
- Trypan blue - vital stain for Reticuloendothelial system)
- Janus Green B - true vital staining of mitochondria
It is done by injecting the dye into any part of the animal body
(either intravenous, intraperitoneal or subcutaneous) producing specific coloration of certain cells, particularly those of the RES
Intravital staining
Common dyes used in Intravital staining:
(LIC)
1. Lithium
2. India ink
3. Carmine
Used to stain living cells immediately after removal from the living body
Supravital staining