Pigment Flashcards
1
Q
What are the three groups of pigment?
A
- Artifact
- Endogenous
- Exogenous
2
Q
What are the two subgroups of endogenous pigments?
A
a. Hematogenous
b. non-hematogenous
3
Q
Non hematogenous pigments can be subdivided into two categories?
A
- Lipidic
- Non-lipidic
4
Q
What are examples of artifact pigments?
A
- Formalin pigments
- Mercury pigments
- Chrome pigments
5
Q
What are examples of hematogenous pigments?
A
- Hemoglobin
- Hemosiderin
- porphyrins
- bile pigments
6
Q
What are examples of non-hematogenous pigments?
A
- Melanin (NL)
- Lipofuchsin (L)
- Ceroid (L)
7
Q
What are examples of exogenous pigments?
A
- Carbon
- Asbestos fibers
- Tattoo pigments
- Metals
8
Q
How are artifact pigments formed?
A
Usually from fixation
9
Q
What are exogenous pigments?
A
Formed externally and taken into the body
10
Q
How are formaldehyde pigments formed?
A
During fixation using acidic formaldehyde solutions.
11
Q
How can formaldehyde pigments be removed?
A
With saturated alcoholic picric acid prior to staining
12
Q
How are mercuric pigments formed?
A
While fixing with mercuric fixatives.
13
Q
How can mercuric pigments be removed?
A
Iodine solution followed by sodium thiosulphate.
14
Q
What do hemosiderin pigments look like?
A
yellow / brown
15
Q
Where might hemoglobin be seen, and what stain does it have an affinity for?
A
- renal tubules post HA and recent hemorrhages
- stains vividly with acidic dyes
16
Q
List two methods which will demonstrate iron.
A
- Prussian Blue
- Turnbull’s blue reaction
17
Q
How are bile pigments demonstrated?
A
By oxidizing bilirubin (yellow/brown) to a greenish biliverdin
18
Q
Where is Melanin found in the human body?
A
- Hair
- Skin
- Retina
- Iris
- CNS
19
Q
What is a malignancy related to melanin called?
A
Melanocarcinoma
20
Q
What is the principle behind lipofuchsins.
A
Slow progressive oxidation process of lipids and lipoproteins, into a brown pigment.
21
Q
Which demonstration methods are useful for lipofuchsins?
A
- PAS
- Oil Red O
- SBB
- Schmorl’s
- Long Ziehl-Neelson
22
Q
What are ceroids?
A
Yellow/brown pigments that are rarely seen in humans, and are positively stained by acid fast staining methods.
23
Q
What are trophi?
A
Large amount of Uric acid and urate crystals which are deposited in soft tissue
24
Q
How can sodium urates be fixed for demonstration?
A
Requires alcohol fixation
25
What principle can be employed to demonstrate urates?
Argentaffin - Methenamine silver method
26
What are neuroendocrine cell’s? and what might be demonstrated in these cells?
- Adrenal chromaffin cells
- Endocrine cells
- Enterochromaffin cells (GI)
- “C” cells of the thyroid
- Pituitary cells
----> Cytoplasmic granules <----
27
How can cells of the neuroendocrine be demonstrated?
- Argentaffin / Argyrophilic reactions
28
Which minerals can be demonstrated by special stains?
- Calcium
- Ferric iron and Ferrous Iron
- Copper
- Phosphate
- Carbon (trioxide??)
29
What is the purpose of Pearl’s Prussian blue technique?
Demonstrate ferric iron in tissue
30
What is the principle of Pearl’s Prussian blue technique?
Detect ferric iron in bound protein complex, endpoint reaction being insoluble coloured pigment.
31
Which fixative is ideal for Pearl’s Prussian blue technique?
- Alcohol
- NBF
32
How large should sections be for the purpose of demonstrating iron?
4-5 microns
33
What reagents are implicated in the Pearl’s Prussian blue technique?
- 2% potassium ferrocyanide
- 2% HCL
- Nuclear-fast red
34
What will nuclei look like after being stained with the Pearl’s Prussian blue technique?
Bright red
35
What will Hemosiderin look like after being stained with the Pearl’s Prussian blue technique?
blue
36
What will the background look like after being stained with the Pearl’s Prussian blue technique?
Pink
37
If you are trying to demonstrate iron in section you suspect might have calcium deposits what must you avoid doing? and why?
Avoid decalcification because the process removes iron.
38
What is the purpose of the Turnbull blue staining method?
Detect ferrous iron in tissue sections
39
Why might a technologist have to use this technique?
Because iron is not normally stored as Fe2+, as it is toxic in this state.
40
What is the principle of Turnbull blue staining method?
Ferrous iron is turned into an insoluble bright blue pigment by treating sections with potassium ferrocyanide.
41
What are the ideal fixatives to use when performing Turnbull blue staining method?
- Alcohol
- NBF
42
What reagents are used to make the potassium ferrocyanide solution?
- Potassium ferrocyanide
- HCL
43
What reagents are used for the Turnbull blue staining method?
- HCL
- Potassium ferricyanide solution
- Acetic acid
- Nuclear-fast red
44
What solutions are used to make the nuclear-fast red in the Turnbull blue staining method?
- Nuclear-fast red
- Aluminum sulfate
- Distilled water
45
What will ferrous iron look like after being stained with the Turnbull blue staining method?
Blue
46
What is the purpose of the Masson-fontana technique?
Demonstration of Argentaffin substances such as melanin.
47
What is the reducing substance used in the Masson-fontana technique?
Phenolic groups
48
What is the purpose of using gold chloride in the Masson-fontana technique??
Tonining
49
What is the purpose of using hypo in the Masson-fontana technique?
Fixing agent
50
What is the ideal fixative to use for the Masson-fontana technique?
- NBF
- Avoid Alcohol
51
What are the reagents used in the Masson-fontana technique?
- Silver nitrate
- Concentrated ammonium hydroxide
- Fontana silver solution
- Gold chloride
- Sodium thiosulphate
- Nuclear-fast red
52
What will melanin look like when stained with the Masson-fontana technique?
Black
53
What will Argentaffin granules look like when stained with the Masson-fontana technique?
Black
54
What will Nuclei look like when stained with the Masson-fontana technique?
Pink
55
You have a tissue section you suspect has both melanin pigments and argentaffin granules, post staining with the Masson-fontana technique you only see black pigment what would you do?
Bleach with Potassium permanganate followed by oxalic acid or peroxide, do bleach out the melanin.
56
What is the purpose of Gomori's methenamine silver method?
Demonstrate urate in tissue
57
What is the principle of Gomori's methenamine silver method?
Urates react with silver to reduce silver to it’s metalic form.
58
What fixative is ideal for Gomori's methenamine silver method?
Absolute alcohol is required
59
Which reagents are used in the Gomori's methenamine silver method?
- Silver nitrate
- Methenamine solution
- Stock methenamine silver nitrate solution
- Sodium borate
- working methenamine silver nitrate
- sodium thiosulphate
- Light green
60
What will urates look like following staining with Gomori's methenamine silver method?
BLACK
61
What will the background stain following Gomori's methenamine silver method?
Green
62
What are the two main methods for demonstrating Calcium?
- Von kossa technique
- Alizarin Red S
63
What is the purpose of the Von kossa technique?
Demonstrate calcium in tissue sections
64
What is the principle of the Von kossa technique?
- Indirectly stains calcium by reacting with the radicals attached or bound to calcium, as calcium can only be demonstrable when bound to carbon and phosphate
----> Argyrophilic reaction <----
65
What reduces the Silver salts into their metallic form in the Von Kossa technique?
Bright lights
66
What removes and un reduced Silver salts from the tissue section in the Von Kossa technique?
HYPO
67
What reagents are used in the Von Kossa technique?
- Silver nitrate solution
- Sodium thiosulphate
- Nuclear-fast red
68
What will calcium salts look like following the Von kossa technique?
Black / Brown
69
What will the background look like following the Von kossa technique?
Pink
70
What will nuclei look like following the Von kossa technique?
RED
71
You stain a section of tissue using the Von kossa technique and notice formalin pigment had formed on the tissue during microscopic analysis of the section. What could explain this?
You used unbuffered formalin
72
You stain a section of tissue using the Von kossa technique and notice the final products of the section are very brown. What could explain this?
The section was exposed to artificial lighting
73
What is the purpose of the Alizarin Red S method?
Demonstrate calcium in tissue sections
74
What is the principle of the Alizarin Red S method?
Calcium forms alizarin red S calcium complex through a chelation process.
75
What are ideal fixatives to use for the Alizarin Red S method?
- NBF
- Alcoholic formalin
76
What reagents are used for the Alizarin Red S method?
- Alizarin red S
- Fast green
77
What will calcium look like following the Alizarin Red S method?
orange - red
78
What will the background look like following the Alizarin Red S method?
green
79
What is the benefit of using the Alizarin Red S method in comparison to the Von kossa technique?
ARS - is more sensitive to small amounts of calcium, simply adjusting the pH of the alizarin red increases its specificity.
