Periodic acid-Schiff (PAS) stain

-

Periodic acid-Schiff (PAS) stain

Introduction:

The periodic acid-Schiff (PAS) stain is a histological method for identifying aldehyde-containing macromolecules such as carbohydrates, glycoproteins, and other compounds in tissue samples. It's frequently used to spot fungi, glycogen, and basement membranes in tissues. Diagnosing disorders such as kidney ailments, fungal infections, and diseases affecting glycogen storage requires the use of PAS staining.

Requirements:

To perform PAS staining, you will need the following materials:

  • Paraffin-embedded tissue sections
  • Periodic acid solution
  • Schiff reagent
  • Hematoxylin solution
  • Different grades of alcohol (70%, 95%, and absolute)
  • Xylene
  • Microscope slides
  • Coverslips

Principle:

In PAS staining, the tissue's carbohydrates are broken down by periodic acid into aldehydes, which combine with the Schiff reagent to give the sample a magenta hue. Fuchsin, a component of the Schiff reagent, combines with the aldehydes to create a magenta colour. To add contrast, apply the hematoxylin counterstain.

Procedure:

  1. Deparaffinize the tissue sections using xylene and graded alcohol.
  2. Oxidize the tissue sections using periodic acid solution for 5-10 minutes.
  3. Rinse the sections with distilled water and immerse in Schiff reagent for 15-30 minutes.
  4. Rinse the sections with running water for 10-15 minutes.
  5. Counterstain the sections with hematoxylin for 1-2 minutes.
  6. Dehydrate the sections with graded alcohol and clear them in xylene.
  7. Mount the sections with a coverslip using a mounting medium.

Results:

The PAS-stained glycogen and other carbohydrates will appear magenta, while the counterstained nuclei will appear blue-black. The cellular structures and tissue architecture can be visualized using a microscope.

QC:

Quality control is essential to ensure accurate staining results. The following measures should be taken:

  • Ensure that the tissue sections are properly deparaffinized.
  • Use fresh staining solutions.
  • Do not over-oxidize the tissue sections with periodic acid.
  • Ensure that the sections are rinsed with distilled water before immersing in Schiff reagent.
  • Do not over-counterstain the sections with hematoxylin.
  • Ensure that the coverslips are properly mounted and secured.

Interpretation:

Based on the presence or lack of carbohydrates and glycoproteins in the tissue sections, PAS staining is used to identify a number of disorders. Glycogen, basement membranes, and fungi can all be detected by pathologists in the tissues. The diagnosis of renal illnesses, fungi infections, and diseases affecting glycogen storage involves the use of PAS staining.

Comments

Post a Comment

Popular posts from this blog

Alcian blue with periodic acid-Schiff (PAS) stain

-
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...
Read more

Alcian blue stain

-
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...
Read more