Pigments (Wk 10) Flashcards
___________ forms a dark green chelate in the presence of copper
Rubeanic acid
Appearance of asbestos in lung tissue?
Brown, beaded dumbbell appearance
What is a nevus
Benign lesion
Von Kossa’s - how are visible deposits formed?
- Treat tissues w/ silver nitrate
- Light source reduces silver to visible deposit
2 artifact pigments
Formalin
Mercury
Colour and location of bile
Yellow-brown
Liver
Where is chromaffin pigment normally found?
Adrenal medulla
Demonstrated by Turnbull’s Blue stain
Ferrous iron
Melanin immunohistochemical marker
S100
2 methods that demonstrate calcium
Von Kossa (indirect) Alizarin Red (direct, but also stains Mg)
3 categories of pigments
- Endogenous
- Artifact
- Exogenous + minerals
Can be removed w/ iodine and then sodium thiosulphate
Mercury artifact
3 non-hematogenous pigments
Melanin
Lipofuscin
Chromaffin
What coats asbestos
Proteins + hemosiderin
Colour and location of hemosiderin
Yellow-brown
Intracellular (macrophages), sites of hemorrhage
Substances which occur in living matter and absorb visible light
Pigments
This amino acid is acted on by an enzyme to be converted to melanin
Tyrosine
How is melanosis coli demonstrated
Methods that demonstrate lipofuscin
What reduces ammoniacal silver in Masson-Fontana method?
Melanin
Typical locations of lipofuscin
Liver
Heart
Brain
2 possible sources of INTERFERENCE causing weak bonds in Congo Red
- Salt
- Alkalinity
How is hemoglobin demonstrated?
Diamino benzidine + H2O2
OR
Leuco patent blue
Main difference in the components of Perl’s vs Turnbull’s stain?
Perl’s - ferrOcyanide
Turnbull’s - ferrIcyanide
Brown pigment sometimes in macrophages in colon (misc. pigment)
Melanosis coli
Endogenous pigments can be further subdivided into these 3 categories
Hematogenous
Non-hematogenous
Endogenous minerals
_________ forms a red product w/ copper
Rhodanine
Amyloid tissue must be cut at this thickness
6-10 microns
3 exogenous pigments/minerals
Tattoo pigment
Carbon
Asbestos
Why isn’t formalin required in MF stain?
argentaffin method = no external reducing agent required
Stain that demonstrates hemosiderin
Perl’s Prussian Blue
Tyrosine -> _______ -> melanmin
DOPA
2 components of Fouchet’s
Trichloroacetic acid
Ferric chloride
2 other argentaffin substances (not melanin) that may also stain in the MF method
Chromaffin
Lipofuscin
Weak amyloid staining may be due to these 3 factors
- Prolonged formalin fixation
- Old control sections
- Old reagents
What do calcium deposits in tissue represent?
Previous inflammation or injury
3 endogenous mineral pigments
Calcium
Copper
Urates
Stain that demonstrates bile and how
Fouchet’s
Oxidizes bilirubin to green biliverdin
Method for demonstrating melanin that involves ferric ions
Schmorl’s
How to demonstrate asbestos?
Perl’s stain of asbestos - shows hemosiderin coating the asbestos
2 components of Turnbull’s blue
Acid
Potassium ferricyanide
2 methods that demonstrate copper
Rubeanic acid (green) Rhodanine (red)
Which stain is this?
Melanin reduces ferric to ferrous ions and then combines with ferricyanide
Schmorl’s
AKA “wear and tear” pigment
Lipofuscin (results from breakdown of lipids)
Masson-Fontana counterstain
Neutral red
2 components of working iron reagent in Perl’s Prussian blue
1:1 ratio HCl + potassium ferrOcyanide
