Carbohydrate Staining

Question 1

Which diagnostic applications do carbohydrate demonstration have?

Answer 1

INCREASED
-Congenital pathological conditions
- Inflammatory reactions
- necrotic tissue
DECREASED
- cytoplasmic liver (wasting disease and diabetes)

Question 2

Which carbohydrates cannot be demonstrated in tissue sections?why?

Answer 2

• Glucose
• Oligosaccharides
  Bc soluble in aqueous solutions

Question 3

What are the 4 groups of naturally occuring polysaccharides?

Answer 3

• 1: Neutral polysaccharides
• 2: Acid mucopolysaccharides
• 3: Glycoproteins
• 4: Glycolipids

Question 4

Which stains can be used to demonstrate carbohydrate and mucosubstances?

Answer 4

• PAS
• Alcian Blue pH2.5 method
• Alcian Blue pH1.0 method
• Alcian Blue & PAS

Question 5

What will PAS demonstrate?

Answer 5

• Glycogen
• Neutral mucopolysaccharides
• Basement membrane
• fungal infections

Question 6

What is the principle of PAS staining method?

Answer 6

Histochemical reaction, not staining.

Question 7

What is the principle of colour formation when collagen is stained with PAS?

Answer 7

Carbohydrate structures have to be oxidized to expose aldehyde groups. aldehyde groups react with Schiff reagent = magenta colour

Question 8

What counter stain is used in PAS?

Answer 8

Hematoxylin = nuclei

Question 9

What results are expected from PAS?

Answer 9

PAS pos substances = magenta
Nuclei = blue

Question 10

Which fixatives should be used for PAS demonstrations?

Answer 10

NBF
Bouins
Alcohol or Alcohol picric acid = best bc less glycogen loss

Question 11

Which tissue are best for the use of PAS?

Answer 11

Kidney
Skin
Duodenum
Normal liver
Fungal sections

Question 12

What is the purpose of dPAS? (diastase method)

Answer 12

demonstration of glycogen

Question 13

What is the principle of dPAS?

Answer 13

enzymatic treat of section with diastase with digest glycogen, followed by PAS staining = confirmation of glycogen (requires one slide dPAS and one slide just PAS)

Question 14

Which sections are best for dPAS method?

Answer 14

Liver with glycogen
Cervix

Question 15

When frozen sections are used for quick demonstration/detection of glycogen what colour will glycogen stain?

Answer 15

Dark brown

Question 16

What is the difference between Alcian Blue at a pH of 2.5 and 1.0

Answer 16

Alcian Blue at pH2.5 will stain carboxylated and sulfated acid mucopolysaccharide turquoise blue and nuclei pink/red. where as pH1.0 = sulphated mucins dark blue and background light blue.

Question 17

Which tissues are best for the demonstration of Alcian Blue

Answer 17

• Small intestine
• Appendix
• Colon

Question 18

You stain a section of colon with Alcian blue and get excess background staining. What went wrong?

Answer 18

pH was above 2.5
staining for too long
Alcian blue - too concentrated
Not rinsed Acetic Acid post ABS

Question 19

You stain a section of colon with Alcian blue and you notice the nuclei are also stained alcian blue. What went wrong?

Answer 19

• Staining too long
• improper rinsing post staining

Question 20

What is the purpose of using Alcian blue and PAS together?

Answer 20

distinguish neutral and acidic mucosubstances

Question 21

What results are expected from staining tissues with Alciant Blue & PAS?

Answer 21

• Acid mucins =deep blue
• Neutral mucins = magenta (PAS+)
  -Tissue = deep purple/blue

Question 22

What is the purpose of staining Alcian Blue with hyaluronidase?

Answer 22

Differentiate epithelial from connective tissue mucins.

Question 23

What is the principle of Alcian blue & hyaluronidase?

Answer 23

Testicular hyaluronidase can be used to to digest connective tissue mucins (hyaluronic acid) to improve staining.