Staining

Question 1

_____________ refers to the procedures in which tissue sections act as the medium in which biochemical reactions are carried out by the addition of substrates, inhibitors, or other chemicals.

Answer 1

Histochemistry

Question 2

A ___________ is a colouring agent.

Answer 2

Chromogen

Question 3

The __________ is the component that is stained.

Answer 3

Substrate

Question 4

___________ substances bond to acidic groups or dyes.

Answer 4

Acidophilic

Question 5

______________ substances bind to basic groups or dyes.

Answer 5

Basophilic

Question 6

Give an example of a dichrome stain.

Answer 6

Haematoxylin and eosin

Question 7

Masson’s trichrome has ____ component dyes.

Answer 7

Three

Question 8

Staining reactions have both _________ and chemical characteristics.

Answer 8

Physical

Question 9

Dye may actually be dissolved in the stained substrate; most ____ staining is achieved by this method.

Answer 9

Fat

Question 10

A dye may be absorbed on the surface of a structure, or may be __________ within the structure.

Answer 10

Precipitated

Question 11

Give two examples of how union between a dye and stained substance can be brought about.

Answer 11

Salt linkages and hydrogen bonds

Question 12

True or false: staining is generally predictable, but can vary.

Answer 12

True

Question 13

State two features which may affect staining efficacy.

Answer 13

Ionic strength of solutions used and temperature

Question 14

Staining by direct bonding exploits the affinity for _______ found in a cellular component, due to binding and bonding.

Answer 14

Chromogen

Question 15

Staining by adsorption involves _______ ____ staining.

Answer 15

Metallic ion

Question 16

What method of staining is used to visualise fungi?

Answer 16

Adsorption

Question 17

Staining by solubility accounts for ____ staining.

Answer 17

Lipid

Question 18

____ ____ __ is used to visualise lipids.

Answer 18

Oil Red O

Question 19

Chemical reactions include insoluble precipitate formation, due to a substrate creating a chromogen at the site of reactivity. What stain can achieve the above?

Answer 19

Perl’s Prussian Blue

Question 20

Schmorl’s stain uses reducing compounds to attract and reduce ___________ to ferrocyanide.

Answer 20

Ferricyanide

Question 21

Indirect methods, through antibody- or oligonucleotide probe-binding to the substrate, link to ___________.

Answer 21

Chromosomes

Question 22

Perl’s Prussian Blue is used for ______.

Answer 22

Iron

Question 23

Periodic Acid Schiff (PAS) stain is used for __________.

Answer 23

Carbohydrates

Question 24

List three natural dyes.

Answer 24

Henna, carmine, and haematoxylin

Question 25

List three synthetic dyes.

Answer 25

Eosin, methyl blue, and neutral red

Question 26

__________ ________ numbers identify specific dyes.

Answer 26

Colour index

Question 27

Dyes generally have an _______ structure.

Answer 27

Aromatic

Question 28

_______________ structure enable the visibility of dyes.

Answer 28

Chromophoric

Question 29

The chromophore is the portion of a molecule's structure which absorbs visible light _________, causing the molecule to have colour.

Answer 29

Photons

Question 30

Nitro dyes, such as picric acid, have a __________ group as the chromophore.

Answer 30

Nitro

Question 31

_____ dyes, such as Orange G and xanthene, have a -N=N group as the chromophore.

Answer 31

Azo

Question 32

Acidic dyes bind to basic tissue elements, and exist as _________ in solution.

Answer 32

Anions

Question 33

_______ dyes bind to acidic tissue elements, and exist as cations in solution.

Answer 33

Basic

Question 34

________ dyes stain through solubility.

Answer 34

Neutral

Question 35

Any substance that is stained by basic dye is _________, carrying acids groups which bind the basic dye through salt linkages.

Answer 35

Basophilic

Question 36

A substance that is stained by an ______ dye is referred to as acidophilic, carrying basic groups to bind acid.

Answer 36

Acid

Question 37

Wright's stain is an example of a ________ stain.

Answer 37

Neutral

Question 38

Neutral stains are ___________ of acid and basic dye.

Answer 38

Compounds

Question 39

Neutral stains are ___________ of acid and basic dye.

Answer 39

Compounds

Question 40

The resultant precipitates of neutral dyes are usually insoluble in water, but soluble in _________.

Answer 40

Alcohol

Question 41

____________ dyes stain one component.

Answer 41

Progressive

Question 42

____________ dyes overstain all components, and excess must be removed.

Answer 42

Regressive

Question 43

Differentiation is the microscopic control of dye removal, breaking bonds of _______-bound dye.

Answer 43

Weakly

Question 44

An accelerator increases staining power, without acting as a __________.

Answer 44

Mordant

Question 45

Fluorescent dyes emit light under ____.

Answer 45

UV

Question 46

_____________ stains give different colours to the dye solution.

Answer 46

Metachromatic

Question 47

Lyoschrome dyes demonstrate lipids, and are _______________ stains that rely on solubility.

Answer 47

Hydrophobic

Question 48

True or false: microanatomical dyes are used for demonstrating general relationships between cellular components.

Answer 48

True

Question 49

___________ dyes emphasise minute structure.

Answer 49

Cytological

Question 50

What is a mordant?

Answer 50

Chemical that serves as a link between the dye and the substrate, resulting in an insoluble compound that helps adhere the dye to the cells

Question 51

Haematein (from haematoxylin) has poor ________, and must be combined with a mordant, before use as a nuclear stain.

Answer 51

Affinity

Question 52

Mordants confer a _________ charge, enabling binding to anionic tissue.

Answer 52

Positive

Question 53

True or false: alum, iron, and tungsten are not examples of mordants.

Answer 53

False

Question 54

A 'haematoxylin lake' results from the combination of a mordant and what substance?

Answer 54

Haematein

Question 55

Application of silver or gold solution produces black, insoluble _________ deposits, on selected reactive sites.

Answer 55

Metal

Question 56

Reduction of metal salts to the metallic state by _________ ________ occurs during adsorption staining.

Answer 56

Tissue aggregates

Question 57

State the principle of Perl's Prussian Blue stain.

Answer 57

The stain causes production of coloured, chemical compound, through interaction of a series of chemical solutions, with reactive tissue component. Tissue is treated with 2% hydrochloric acid, to liberate ferric iron from protein complexes, and then with potassium ferrocyanide, to allow ferrocyanide ion complexes to interact with ferric ion, to form a blue compound. It is useful in demonstrating haemochromatosis

Question 58

What is the principle of the Periodic Acid Schiff (PAS) stain?

Answer 58

Firstly, tissue is treated with 1% periodic stain, whereby groups in hexose molecules are oxidised to dialgehyde, then treated with Schiff reagent, to bind dialdehydes, and recolour basic fuchsin, to turn magenta pink

Question 59

What two modifications must be made to haematoxylin before it is used?

Answer 59

Oxidation, and addition of metal ion

Question 60

Outline four mordants used with haematoxylin, and why they are used.

Answer 60

Aluminium stains nuclei red initially, which turns to blue-black after washing, and can be used to stain regressively, where the section is overstained, and the tissue is differentiated, then 'bluing up' is performed. Iron demonstrates a greater range of structures than aluminium. Tungsten uses 1% phosphotungstic acid as the mordant, staining blue-purple. Lead is useful for demonstration of granules in GI tract tissues

Question 61

Although primarily used to stain nuclei, ___________ will also stain rough ER, ribosomes, collagen, myelin, elastic fibres, and acid mucins.

Answer 61

Haematoxylin

Question 62

Haematoxylin may be used progressively, in which the length of time the tissue remains in contact with the staining solution is used to control the amount of colouration, or regressively, in which the tissue is over-stained, and excess stain is removed by _____________.

Answer 62

Differentiation

Question 63

________ is a fluorescent, xanthene, synthetic dye, which binds salts with eosinophilic compounds containing positive charges.

Answer 63

Eosin

Question 64

True or false: eosin is negatively-charged.

Answer 64

True

Question 65

What is eosin's primary staining target?

Answer 65

Cytoplasm

Question 66

Most staining is performed in an __________ stainer.

Answer 66

Automated

Question 67

Participation in external quality programmes, such as _________ , is important.

Answer 67

NEQAS

Question 68

In Masson's trichrome, what is Solution A?

Answer 68

Acid fuchsin in distilled water

Question 69

In Masson's trichrome, what is Solution B?

Answer 69

Phosphomolybdic acid in distilled water

Question 70

What is Solution C usually, when found as part of Masson's trichrome?

Answer 70

Methyl blue

Question 71

Phosphomolybdic acid acts as a differentiator, forcing _________ of the acid dye out of collagen, while retaining it in the cytoplasm (collagen is less permeable than cytoplasm).

Answer 71

Diffusion

Question 72

______________ ______facilitates the binding of aniline blue (or other dye) to the decolourised collagen.

Answer 72

Phosphomolybdic acid

Question 73

What is the order of application of the stains of Masson's trichrome?

Answer 73

Haematoxylin, Solution A, Solution B, and Solution C

Question 74

Masson's technique discerns _________ from muscle fibres.

Answer 74

Collagen

Question 75

RBC are least permeable, and are coloured by dyes with _________ molecular size in trichrome staining.

Answer 75

Smallest

Question 76

_______ increases the rate of penetration in trichrome staining.

Answer 76

Heat

Question 77

Trichrome specimens must be prepared in a _____ pH, to achieve adequate and even staining of connective tissue.

Answer 77

Low