Histopathology and Cytopathology Department SOPs

The Alcian blue with periodic acid-Schiff (PAS) stain is a combination staining technique used in histology to detect and differentiate acidic and neutral mucins, as well as other carbohydrates, in tissue sections. This dual staining method allows for the identification and localization of both acidic and neutral mucosubstances in various tissues. Principle: The principle of the Alcian blue with PAS stain involves two different staining reactions: Alcian blue staining: Alcian blue dye binds to acidic mucins, highlighting their presence. The dye forms a complex with the acid mucopolysaccharides and glycosaminoglycans (GAGs) present in the tissue sections. Periodic acid-Schiff (PAS) staining: The PAS reaction involves the oxidation of carbohydrates present in the tissue sections by periodic acid, followed by the reaction of the oxidized carbohydrates with Schiff's reagent. This reaction results in the formation of a pink or magenta color, indicating the presence of neutral mucins and...

The Alcian blue stain is a histological staining technique used to detect and differentiate acidic mucins and other acid glycosaminoglycans (GAGs) in tissue sections. It is commonly employed in various fields such as histopathology, embryology, and connective tissue research to assess the presence and distribution of acidic mucins in tissues. Principle: The principle of the Alcian blue stain is based on the selective affinity of Alcian blue dye for acidic mucopolysaccharides and GAGs. The staining involves the following steps: Tissue pretreatment: Tissue sections are usually deparaffinized and rehydrated to remove the paraffin and restore the tissue's hydration. Alcian blue staining: The tissue sections are immersed in an Alcian blue solution, typically at a pH of 1.0 or 2.5. The Alcian blue dye binds to the acidic mucins and GAGs present in the tissue. Counterstaining: In some protocols, a nuclear counterstain, such as nuclear fast red or hematoxylin, is used to visualize the cell...

Masson's trichrome stain is a histological staining technique used to differentiate and visualize different tissue components in histology slides. It is particularly useful for highlighting collagen fibers, muscle fibers, and other connective tissues. The stain involves a series of color changes that allow for the identification and differentiation of various tissue components. Principle: The principle of Masson's trichrome stain is based on the differential affinity of tissue components for specific dyes. The stain involves three main steps: Nuclear staining: The tissue section is stained with a nuclear stain, usually Harris hematoxylin. This step imparts a blue color to the cell nuclei. Cytoplasm and muscle fiber staining: The tissue section is treated with a mixture of acidic dyes, such as acid fuchsin and ponceau acid fuchsin. This step stains the cytoplasm, muscle fibers, and keratin in red or pink. Collagen staining: The tissue section is immersed in aniline blue or light...