Module 10: Myelin and Nissl Staining

Question 1

What is myelin?

Answer 1

white substance forming sheaths around axons

Made of protein, cerebrosides, cholesterol, phospholipids, etc

Question 2

What produces myelin?

Answer 2

Schwann cells in the PNS

Oligodendrocytes in the CNS

Question 3

What part of myelin is left after processing?

Answer 3

Neuroketain, a proteolipid

Question 4

How does myelin stain in an H&E?

Answer 4

Stronger pink than non-myelinated nerves

Difficult to pick out

Question 5

What staining method is often used to detect myelin?

Answer 5

Immunohistochemical techniques

Question 6

What is myelin demonstration useful for?

Answer 6

Demonstration of demyelinating disease like multiple sclerosis

Question 7

What are the positive and negative techniques used in staining for myelin?

Answer 7

Positive - stains degenerate myelin

Negative - stains normal myelin

Question 8

What is an example of a negative technique for myelin?

Answer 8

Luxol fast blue

Question 9

What is Nissl substance?

Answer 9

Acidic aggregations of rough endoplasmic reticulum

Also called tigroid or chromidal substance

Question 10

Where is Nissl substance found?

Answer 10

In the cytoplasm and dendrites of neurons

Question 11

What are good stains for Nissl substance?

Answer 11

Cresyl Echt Violet

thionin

Question 12

What types of dyes are the ones used for Nissl substance?

Answer 12

Basic analine dyes

Question 13

What happens to Nissl substance when nerve damage occurs?

Answer 13

It starts to disappear, first around the nucleus then throughout the cytoplasm

Question 14

Describe the 3 stages of myelin degeneration

Answer 14

Early - myelin still present
Intermediate - lipid breakdown to neutral fats
Final - neither fat nor myelin present

Question 15

Describe what will stain in the 3 stages of myelin degeneration

Answer 15

Early - myelin with Luxol fast blue
Intermediate - neutral lipid with oil red O
Final stages - nothing

Question 16

What diseases cause demyelination?

Answer 16

Multiple sclerosis
Untreated pernicious anemia
Nerve damage
Possibly bipolar disease and certain psychoses

Question 17

What type of dye is Luxol fast blue?

Answer 17

Copper phthalocyanin dye

Question 18

What is the Luxol fast blue - Cresyl echt iolet stain used for?

Answer 18

Illustrating normal myelin and Nissl substance

Will show loss is damage has occured

Question 19

What is the principle of the luxol fast blue dye?

Answer 19

Copper phthalocyanine dye

Lipoprotein base replaces the basic group of the dye molecule

Question 20

What is the principle of the cresyl echt violet dye?

Answer 20

Nissl is acidic and stains wil basic dye

Question 21

What is luxol fast blue made from?

Answer 21

Luxol fast blue
95% alcohol (solvent)
10% acetic acid

Question 22

What is cresyl echt violet made from?

Answer 22

cresyl echy violet
distilled water (solvent)

Question 23

What differentiates the luxol fast blue?

Answer 23

0.05% lithium carbonate (quickly)

70% alcohol (slowly)

Question 24

What differentiates cresyl echt violet?

Answer 24

95% alcohol
chloroform
glacial acetic acid

Question 25

What is a good control slide for luxol fast blue - cresyl echt violet?

Answer 25

Nevous tissue like cerebral cortex

Question 26

What are the expected results for luxol fast blue - cresyl echt violet?

Answer 26

Mylein - blue Nissl substance - purple Nuclei - purple

Question 27

Luxol fast blue is a _______ _______ dye. It's staining is due to the presence of _______. Cresyl echt violet is a ______(acidic/basic) dye which stains acidic tissue components such as ____ found in _____ _______.

Answer 27

``` copper phthalocyanin lipoprotein basic RNA Nissl substance ```

Question 28

This method is considered a _______ technique as degenerated myelin is demonstrated by the _______ of staining. Only _______ myelin will stain.

Answer 28

negative absence normal