Ch. 1 - Stains

Question 1

Masson’s trichrome stain

Answer 1

Differentiates collagen (blue-green) from smooth muscle (red)

*Very young collagen can stain red

Question 2

Verhoeff-Van Gieson stain

Answer 2

Stains elastic fibers black

Question 3

Toluidine blue

Answer 3

Stains mast cells metachromatically (dye is blue, granules are purple). Also stains acid mucopolysaccharides.

Question 4

Leder stain (naphthol ASD chloroacetate esterase)

Answer 4

Mast cell cytoplasm stains red (independent of granules). Also stains myeloid cells.

Question 5

PAS (Periodic acid-Schiff)

Answer 5

Stains glycogen, neutral mucopolysaccharides (eg basement membrane), and fungi red.

*Diastase-treated glycogen will not stain red.

*Acid mucopolysaccharides (eg hyaluronic acid) will not stain.

Question 6

Alcian blue

Answer 6

Stains acid mucopolysaccharides (eg dermatan, chondroitin, hyaluronic acid) blue.

*Can be used with or without hyaluronidase

Question 7

Colloidal iron

Answer 7

Stains acid mucopolysccharides blue.

*Can be used with or without hyaluronidase

Question 8

Mucicarmine

Answer 8

Stains acid mucopolysaccharides pink to red, as well as the mucinous capsule of Cryptococcus neoformans

Question 9

Congo red

Answer 9

Stains amyloid brick-red and displays “apple green” birefringence under polarized light.

Question 10

Thioflavin T

Answer 10

Stains amyloid with yellow to yellow-green appearance under fluorescence microscopy.

Question 11

Crystal violet

Answer 11

Stains amyloid metachromatically (red-purple)

Question 12

Prussian blue (Perls stain)

Answer 12

Stains ferric ions a deep blue.

*Stains hemosiderin but not heme

Question 13

Fontana-Masson

Answer 13

Silver stain that precipitates melanin black.

Question 14

Von Kossa

Answer 14

Silver stain that stains calcium salts black.

Question 15

Alizarin red

Answer 15

Directly binds calcium ions staining them orange-red

Question 16

Oil red O

Sudan black

Osmium tetroxide

Answer 16

All stain lipid and require fresh frozen tissue (lipid is removed during routine processing)

Question 17

Brown-Hopps

Answer 17

Stains gram-positive organisms blue and gram-negative organisms red.

(modification of the Brown-Brenn technique)

Question 18

GMS (Grocott’s methenamine silver)

Answer 18

Reacts with fungal wall to turn it grey-black. Also stains Nocardia and Actinomyces.

Question 19

Acid-fast stains (Ziehl-Neelsen, Fite, Kinyoun)

Answer 19

Stains mycobacteria bright red.

*Fite is preferred for “partially acid-fast” organisms.

Question 20

Auramine-rhodamine

Answer 20

Stain for mycobacteria, fluoresces reddish-yellow.

Question 21

Warthin-Starry

Dieterle

Steiner

Answer 21

Silver stain resulting in black spirochetes (lyme, syphilis). Also stains Legionella, Bartonella, and Donovan bodies of granuloma inguinale.

Question 22

Giemsa

Answer 22

Many uses including highlighting myeloid and mast cell granules purplish blue. Also stains many organisms including Leishmania, Histoplasma, and many bacteria.

Question 23

What transport media should be used for electron microscopy? Immunofluorescence?

Answer 23

EM: Glutaraldehyde

IF: Michel’s medium (ammoniu sulfate). Saline is OK too.