300 Feulgen and PAS Technics (chap. 19) 



B. SOLUTIONS (aqueous): 

 Periodic acid: 



periodic acid (HIO4) 0.6 gm. 



distilled water 100.0 ml. 



nitric acid, concentrated 0.3 ml. 



Schiff's reagent, see page 294. 

 Sulfite solution, see above procedure. 



procedure: 



1. Deparaffinize and hydrate slides to water; remove HgCl2. 



2. Treat with periodic acid, aqueous: 5 minutes. 



3. Wash in riuming water: 5 minutes. 



4. Treat with Schiff's reagent: 10 minutes. 



5. Transfer through sulfite solutions, 3 changes: 1.5-2 minutes in 

 each. 



6. Wash in running water: 5 minutes. 



7. Coiniterstain, if desired (see Comments, number 3). 



8. Dehydrate, clear, and mount. 



results: 



Many tissues give positive PAS reactions: glycogen, starch, cellulose, 

 mucins, colloid of thyroid, cartilage matrix, chitins, reticulum, fibrin, 

 collagen — rose to purplish-red 



fungi — red 



nuclei and other tissue elements — colors of coiurterstain 



comments: 



1. When preparing slides, avoid excessive use of egg albumen; it con- 

 tains sufficient carbohydrate to react with the Schiff. 



2. Control Slides: 



To remove glycogen^ run the slides down to water and subject 

 them to the saliva test. Saliva contains a diastatic enzyme which 

 dissolves glycogen and starch. Instead of saliva, a 1% solution of 

 salt or animal diastase can be used for 20 minutes to overnight at 

 room temperature. 



To remove mucin, treat slides with Lysozyme, 0.1 mg. to 10.0 

 ml. of Sorensen M/15 phosphate buffer (page 417), pH 6.24, room 

 temperature: 40-60 minutes. 



To remove RNA, treat slides with 0.01 mg. RNase in 10.0 ml. 

 0.2M acetate buffer (page 414), pH 5.0 at room temperature: 10- 

 15 minutes (or tris-HCl buffer, 0.05M, pH 7.5: 2 hours, 56°C). 



