Lecture 3: Tissue Prep and Staining

Question 1

Hematoxylin and eosin (H&E) stain

Answer 1

commonly used for routine staining because they display structural features

Hematoxylin: cytoplasmic components stained dark blue/light blue/purple; behaves like a basic dye

Eosin: acid dye; stains cytoplasmic components and extracellular material yellow/pink

Question 2

Toluidine Blue stain

Answer 2

Basic dye; metachromatic - characteristic color change when staining certain elements

Question 3

Metachromasia

Answer 3

Phenomenon whereby a dye changes color after reacting with a tissue component

Ex: toluidine blue used to stain cartilage ground substance, mast cell granules

Question 4

Sudans, Oil Red O, Nile blue stains

Answer 4

Appropriate to stain lipids because they are lipid soluble.

Question 5

Periodic Acid-Schiff Reaction (PAS)

Answer 5

Cleaves bonds between adjacent carbons of carbohydrates and forms aldehyde groups; deep pink stain

STAINS CARBS such as glycogen, GAGs, proteoglycans, glycoproteins, glycolipids

Question 6

When would you use an immunocytochemical stain?

Answer 6

To study presence of specific antigens (using monoclonal antibodies); indirect labeling is more commonly used method