Med. App: Selected Stains and Reactions

Question 1

Acid dyes

Answer 1

• Chemicals with net negative charge
• Bind to acidophilic structures
• ex: esoin

Question 2

Basic dyes

Answer 2

• Chemicals with net positive charge
• Bind to basophilic structures
• ex: hematoxylin

Question 3

Acidophilic

Answer 3

• Structures that possess a net positive charge
• Have an affinity for negative acid dye
• ex: mitochondrion

Question 4

Basophilic

Answer 4

• Structures that possess a net negative charge
• Have an affinity for positive basic dye
• ex: nucleus

Question 5

Metachromasia

Answer 5

• phenomenon in which a given stain imparts different colors to the tissue
• Ex: toluidine blue stains blue, purple, and red in granulated mast cells. The red granules contain heparin (a glycosaminoglycan) which has negative sulfate molecules which bind to stain causing color change.

Question 6

Hematoxylin and eosin

Answer 6

• H (blue) : RNA,DNA, ribosomes, and rER
• E (pink): secretory vesicles, sER, lysosomes, mitochondria, and type I collagen
• H and E stain coagulative necrosis (the tighter packed, dk. pink is necrotic)

Question 7

Feulgen reaction

Answer 7

• (Magenta) DNA

- Can be used to demonstrate nuclear changes in cancer

Question 8

Mallory triple

Answer 8

• (Red) nuclei
• (Red to orange) muscle
• (Blue) collagen
• (Blue) hyaline cartilage
• Can be used to highlight fibrosis (abnormal accumulation of collagen, shallow and rapid breathing due to lung restrictions)

Question 9

PAS reaction (periodic acid shift)

Answer 9

• (Magenta) Carbohydrates and polysaccharides
• Can be used to detect thickened basement membranes in kidney disease, glycogen storage disease, and in alpha1-antitrypsin (AAT) deficiency in hepatocytes (AAT misfolds and accumulates in the rER)

Question 10

Osmic Acid

Answer 10

• (Black) lipids

Question 11

Verhoeff

Answer 11

• (Black) elastic fibers

- Can discriminate thinning in Marfan syndrome

Question 12

Silver methods

Answer 12

• (Black) intermediate filaments of nerve cells, glial cells, and reticular fibers

Question 13

Tryphan blue

Answer 13

• (Blue) macrophages (by ingestion)

Question 14

Prussian blue

Answer 14

• (Blue) Hemosiderin (ferric iron)

- Can be used to demonstrate excessive iron accumulation in hemochromatosis

Question 15

Nissl

Answer 15

• (Blue) ribosomes

Question 16

Iron hematoxylin

Answer 16

• (Dk. blue to black) nuclear elements, chromosomes, mitochondria, centrioles, and muscle striation

Question 17

Congo red

Answer 17

• (Red) extracellular deposits of amyloid (pathologic accumulation)