Staining Mechanisms
Oil Red O utalizes this staining mechanism
Physical
Chromotrope 2R and Phosphotungstic Acid stain these tissues red in the Gomori 1 Step Trichrome
Muscle and Cytoplasm
This is the toner used in most silver staining methods
Gold chloride
This is how to remove cloudiness that may appear on slides counterstained with nuclear fast red
Back up to the tap water rinse then continue dehydration and clearing steps
Sections to demonstrate glomerular basement membranes should be this thickness
2 microns
Mast cells stained with toluidine blue are said to stain by this staining mechanism
Metachromatic Staining (Mast cells stain purple while the dye solution and other tissue elements are blue or orthochromatic)
Picric acid and Acid fuchsin are components of this staining solution
Van Gieson
Fat is chemically fixed and maintained through routine processing in tissue by this solution
Osmium tetroxide
This is the result of using metal forceps or glassware that wasn't chemically cleaned during silver staining methods
Non-specific silver staining and/or precipitation
This is how preparing tissues for Oil Red O differs from routine paraffin processing/microtomy
Frozen tissues are embedded in OCT (Optimal Cutting Temperature media) and sectioned with a cryostat
Mallory PTAH is this type of staining solution
Polychromatic (1 solution that gives 2 major colors)
When using this solution to stain basement membranes, the endpoint should be determined by the glomerular basement membranes rather than the tubular membranes. Slides should be checked frequently in this solution as optimum staining intensity is difficult to achieve.
Methenamine Silver Solution
This is the role of Phophotungstic and/or phosphomolybdic acid in the Masson Trichrome method
Removes Biebrich scarlet from collagen so that it can be counterstained
This may result in collagen that is the same color as cytoplasm and muscle in the van Gieson picric acid-acid fuchsin stain
Not using saturated picric acid
This is the preferred fixative for Masson Trichrome or mordant for formalin fixed tissues
Bouin solution
Alkaline alcohol converts Alcian blue into this insoluble pigment in the Movat Pentachrome procedure
Monastral fast blue
Iron hematoxylin is used rather than aluminum hematoxylin for nuclear staining in Trichrome methods for this reason
Subsequent acid solutions would decolorize aluminum hematoxylin stained nuclei
Ferric chloride performs these functions in the Verhoeff Elastic stain
This may cause faded blue staining of connective tissue in the Masson Trichrome stain
Over-differentiation in acetic acid solution or collagen that is pathologically altered
In this stain the differentiation step is very critical and can be variable from slide to slide. It is recommended to differentiate each slide individually.
Verhoeff Elastic Stain (Verhoeff-van Gieson)
This type of tissue/reaction (ex: Reticulin fibers) has the ability to adsorb silver from solution, but requires a reducing agent to reduce the silver to a visible metallic form
Argyrophilic
These are the 5 dyes of the Russel-Movat Pentachrome stain
Alcian blue: Acidic mucosubstances and ground substance
Iron hematoxylin: Elastic fibers and Nuclei
Crocein scarlet and acid fuchsin: Muscle and Cell cytoplasm
Alcoholic Safran: Collagen
This can ripen Mallory PTAH for immediate use
Potassium permanganate
In the Movat Pentachrome procedure this may inhibit staining after the Alcian blue step
Incomplete removal of alkaline alcohol during the tap water rinse
Silver impregnation stains for reticulin depend on the formation of this chemical group
Aldehydes (through oxidation of carbohydrates)