Lecture 2 Staining

Question 1

Why is it important to stain?

Answer 1

Overcome a lack of contrast in tissue Identify cell types and cellular structures Identify specific molecules within a tissue (clinical diagnostics)

Question 2

Tissues that stain with a basic stain are ______.

Answer 2

basophilic

Question 3

What are components which are basophilic?

Answer 3

Nuclei or RER in secretory cells

Question 4

Tissues that stain with an acidic stain are _____.

Answer 4

Acidophilic

Question 5

What are components which are acidophilic?

Answer 5

“normal” cytoplasm

Question 6

What are examples of basic dyes?

Answer 6

Methyl green, Methylene blue, Pyronin G (red), Toluidine blue, Hematoxylin

Question 7

What type of stain is this, what are the different structure being stained?

Answer 7

H&E

nuclei = blue (basophilic) → Hematoxylin

cytoplasm = pink (acidophilic) → Eosin

Question 8

Most carbohydrates react with ______ to produce aldehydes, which convert the colourless ______ reagent (Basic Fuchsin) to pink, or magenta.

Answer 8

Periodic acid, Schiff, PAS stain

Question 9

What are examples of tissues that stain well with PAS?

Answer 9

Glycogen, mucin, elastic fibers, reticular fibers, basement membranes, thyroid colloid, basophilic granules in the pituitary gland, and other polysaccharides such as the ground substance of cartilage are stained fuchsia or pink.

Question 10

Enzyme digestion with diatase would stain well with?

Answer 10

PAS

Question 11

_____ is used to stain an extracellular matrix after a nuclear and cytoplasmic stain has been used (H&E).

Answer 11

Mallory’s trichrome

Question 12

This is an example of what stain, what is the blue structure?

Answer 12

Mallory’s trichrome, collagen

Question 13

What is a “change of colour stain” and what are examples?

Answer 13

metachromatic

Azure, toluidine blue

Question 14

Mast cells (mediators of inflammation) stain purple in an otherwise blue background is an example of what class of stain?

Answer 14

metachromatic

Question 15

______ dye combination stains chromatin shades of purple and cytoplasm and collagen a lighter violet.

Answer 15

Pararosaniline-toluidine blue (PT)

Question 16

True or False: PT satins do not penetrate plastic sections like H&E.

Answer 16

False, they do

Question 17

______ embedded sections to provide better detail of cell and tissue structures.

Answer 17

Resin

Question 18

______ is also commonly used for differential staining of cellular components, particularly ______.

Answer 18

Toluidine blue, cytoplasmic granules

Question 19

______ use azure blue stains to stain White Blood Cell granules basophilic or neutrophilic, used with eosin for RBC and eosinophilic WBC, and methylene blue stains nuclei.

Answer 19

Wright-Giemsa stain

Question 20

______ is used to trace nerves, stain Golgi, reticular fibers

Answer 20

Silver impregnation

Question 21

What is better for paraffin processing or cryosections when staining lipids?

Answer 21

Cryosections, b/c paraffin will extract lipids (just like droplets)

Question 22

What are the 3 lipid/fat stains?

Answer 22

Sudan Black

Sudan IV (red)

Congo Red

Question 23

______ is used to fix lipids.

Answer 23

Osmium tetroxide

Question 24

How are functioning enzymes viewed in a stain?

Answer 24

A specific enzyme-catalyzed reaction is performed with the section and the reaction product is visualized as an insoluble precipitated on the section.

Question 25

______ fluorescently stains nucleic acids orange.

Answer 25

Acridine orange

Question 26

______ binds DNA and ______ binds actin in flurescent microscopy.

Answer 26

DAPI (4’,6-diamino-2-phenylindol, fluorescein-phalloidin

Question 27

______ are tissue preparations in which particles called silver grains to indicate the cells or regions of cells in which specific macromolecules were synthesized just prior to fixation.

Answer 27

Autoradiography

Question 28

How does in situ hybridization work?

Answer 28

The section is incubated with digoxigenin-labeled complementary DNA (cDNA) probe for the HPV DNA, ISH of this tissue section reveals that many cells (brown) contain the human papillomavirus (HPV).

Question 29

What type of immunochemistry is more common, sensitive and has better control?

Answer 29

Indirect

Question 30

What does this picture show?

Answer 30

Indirect Immunolocalization of the filament protein desmin in a single cultured uterine cell. Nucleus stained with DAPI

Question 31

______ of light at a lower wavelength. ______ of light from the fluorophore at a higher wavelength Difference is ______.

Answer 31

Excitation, Emission, stokes shift

Question 32

True or False: Multiple fluorophores can be viewed in the same section

Answer 32

True

Question 33

What types of microscopy can produce 3D images? And what are the benefits to it?

Answer 33

Confocal microscopy

Reduced blurring of the image from light scattering

Increased effective resolution

Improved signal to noise ratio

Clear examination of thick specimens

Question 34

What two metals are used in TEM staining?

Answer 34

1) Uranyl Acetate
2) Lead citrate

Question 35

True or False: IHC and ISH important in clinical diagnostics

Answer 35

True