What is the role of periodic acid in PAS stain?
PRINCIPLE: The PAS stain is a histochemical reaction in that the periodic acid oxidizes the carbon to carbon bond forming aldehydes which react to the fuchsin-sulfurous acid which form the magenta color. CONTROL: For staining fungus; use a known positive such as those used for the GMS.
What are the uses of periodic acid Schiff stain?
Periodic acid–Schiff (PAS) is a staining method used to detect polysaccharides such as glycogen, and mucosubstances such as glycoproteins, glycolipids and mucins in tissues.
How does periodic acid Schiff PAS stain able to detect carbohydrate deposits in the tissues?
Periodic acid–Schiff (PAS)–diastase. PAS stains both glycogen and α1-AT globules a dark, reddish-purple, and diastase digests the glycogen. Thus, when a PAS-diastase stain is used, the glycogen has been removed by the diastase, and the only positively staining globules are those due to α1-AT.
What is the purpose of the Schiff’s reagent step in the PAS method?
Used for the detection of glycogen in tissues such as liver, cardiac and skeletal muscle on formalin-fixed paraffin-embedded tissue sections, and may be used for frozen sections as well.
What does hematoxylin stain?
Hematoxylin has a deep blue-purple color and stains nucleic acids by a complex, incompletely understood reaction. In a typical tissue, nuclei are stained blue, whereas the cytoplasm and extracellular matrix have varying degrees of pink staining.
What is the staining procedure of PAS stain?
Procedure for Periodic Acid-Schiff (PAS) Staining Rinsing: In distilled water. Aldehydration: Place the stain in Schiff reagent for 15 minutes, which turns light pink. Washing: Using lukewarm tap water, wash the stain for 5 minutes, turning it dark pink. Counterstaining: Add Mayer’s Hematoxylin for 1 minute.
How do you use PAS stain?
Procedure:
- Deparaffinize and hydrate to water.
- Oxidize in 0.5% periodic acid solution for 5 minutes.
- Rinse in distilled water.
- Place in Schiff reagent for 15 minutes (Sections become light pink color during this step).
- Wash in lukewarm tap water for 5 minutes (Immediately sections turn dark pink color).
How do you make Schiff reagent?
Schiff reagent may be made by simply adding 1 g. fuchsin, 1.9 g. sodium metabisulfite to 100 ml. 0.15 N hydrochloric acid, shaking at intervals or mechanically for 2 hours, decolorizing with charcoal and filtering.
What does PAS stain in kidney?
Renal Pathology. This normal glomerulus is stained with PAS to highlight basement membranes of glomerular capillary loops and tubular epithelium. The capillary loops of this normal glomerulus are well-defined and thin. The endothelial cells are seen in capillary loops.
How do you make periodic acid-Schiff stain?
What stains positive for PAS?
Germ Cell Neoplasms of the Ovary Periodic acid–Schiff (PAS) stain highlights the abundant glycogen in the tumor cells; the staining will disappear after diastase treatment. By immunohistochemistry, dysgerminoma cells are positive for PLAP (strong, cytoplasmic staining), SALL4, CD117, and OCT4 (Fig. 16.7).
What is periodic acid Schiff staining?
Periodic-Acid Schiff (PAS) staining technique is used in histochemistry and histological studies to demonstrate the presence of carbohydrates and carbohydrate compounds such as polysaccharides, mucin, glycogen, and fungal cell wall components.
How do you prepare a Schiff reagent for staining?
Deparaffinize and hydrate water. Oxidation: Add 0.5% of the Periodic acid solution for oxidation for 5 minutes. Rinsing: In distilled water. Aldehydration: Place the stain in Schiff reagent for 15 minutes, which turns light pink.
What is the reaction between Schiff reagent and hematoxylin?
A good Schiff reagent will rapidly turn a red-purple color. A deteriorating schiff reagent will give a delayed reaction and the color produced will be a deep blue-purple. Mayer’s Hematoxylin Solution:
What is PAS stain in histopathology?
Periodic Acid Schiff (PAS) Staining Technique For Carbohydrates. Periodic Acid Schiff (PAS) staining is one of the most commonly performed special staining technique in histopathology laboratory which is used to highlight molecules with high percentage of carbohydrate content such as mucin, glycogen, fungi and basement membrane in skin.