FIXATION:        10% buffered neutral formalin.

TECHNIQUE:        Paraffin sections cut at 5 μm.

SOLUTIONS:

1% Periodic Acid

Periodic Acid --------------------------------------------------------------------        1.0 gm

Distilled water -------------------------------------------------------------------        100.0 ml

Thionin Schiff Reagent

Thionin C.I. 52000 --------------------------------------------------------------        1.0 gm

Distilled water -------------------------------------------------------------------        100.0 ml

Sodium hydrosulfite ------------------------------------------------------------                1.0 gm

       Add the thionin to the distilled water and heat to near boiling.

       When the solution has cooled add the sodium hydrosulfite.  A

       grey precipitate forms.  Filter through Whatman #4 filter paper.

       The solution is not stable at room temperature and should be

       prepared shortly before use.  If refrigerated the solution is good

       for one or two days.

0.5% Potassium Hydroxide in 70% Alcohol

Potassium hydroxide -----------------------------------------------------------                0.5 gm

Alcohol, 70% ------------------------------------------------------------------                100.0 ml

Modified Lillie’s Schiff Solution

(See PAS Method)

Use control slide (colon).

1. Deparaffinize and hydrate to distilled water.
2. Place in 1% periodic acid for 15 minutes.
3. Rinse with four changes of distilled water.
4. Place in thionin Schiff reagent for 30 minutes.
5. Wash in running tap water for 10 minutes and rinse in two change of distilled water.
6. Place in 70% alcohol for 30 seconds.
7. Treat with 0.5% potassium hydroxide in 70% alcohol for 5 minutes.
8. Wash gently in running tap water and rinse with two changes of distilled water.
9. Place in 1% periodic acid for 10 minutes.
10. Rinse in four changes of distilled water.
11. Place in modified Lillie’s Schiff solution for 15 minutes.
12. Rinse with three changes of distilled water.
13. Place in 0.3% sodium borate for 15 seconds.
14. Rinse with four changes of distilled water.
15. Dehydrate in graded alcohols.
16. Clear in xylene, three or four changes.

Mount with synthetic resin.

Normal small bowel mucosal mucins ---------------------------                blue

Normal colonic mucin --------------------------------------------                red

Adenocarcinomas of the colon ----------------------------------                blue to purple or non-stained

This is an excellent stain for differentiating colonic mucins from those found in other areas of the GI tract.  It is also helpful in demonstrating the loss of normal mucins in colonic adenocarcinomas, although the specificity of this is as yet undetermined.  Colonic polyps may show similar loss of normal (red) mucin staining.

Culling, C.F.A., Reid, P.E. and Dunn, W.L.:  A new histochemical method for the identification and visualization of both side chair acylated and non-acylated sialic acids.  J. Histochem. Cytochem. 24:1225-1230, 1976.