Pigments CH 11 Flashcards
Pigments
- Pigments are any of the various coloring agents deposited, frequently as cytoplasmic inclusions or granules,
in cells and tissues. - Artifact pigments
- Exogenous pigments
- Endogenous hematogenous pigments
- Endogenous non-hematogenous pigments
Artifact pigments
- Produced from fixation and tissue processing
- Usually lie on top of tissue, although formalin pigment has been seen in cell cytoplasm
- Mercury pigment from mercury containing fixatives is removed by treating sections with iodine, followed by solution of sodium thiosulfate
- Formalin pigments comes from acidic hematins and is birefringent, removed by alcoholic picric acid
Chrome pigment comes from fixatives containing what? And how are they removed?
ANS:
- Removed by treating tissue through running water before dehydration step in processor
Exogenous pigments
- Carbon commonly seen in lung and lymph nodes (anthracotic) resists bleaching and sulfuric acid rinsing
- Asbestos fibers are birefringent and found in lungs, loose birefringent properties and can been demonstrated by Prussian blue. Contains fibers of magnesium silicate
- Tattoo pigments usually found on skin
- Metals are also deposited in tissues
Endogenous Hematogenous pigments
- Derived from blood (hemosiderin, hemoglobin, and bile pigments)
- Iron deposited in tissue as hemosiderin can be demonstrated
- Bile pigments such as billiverdin also results from destruction of RBC’s
- Hematoidin involves similar stain principle as bile pigments
- Hemofuscin can be present in portal areas of liver with primary biliary cirrhosis
Endogenous nonhematogenous pigment
- Nonlipidic: melanin is most important. Derived from tyrosine oxidized to dopa for staining
- May be bleached with oxidizing agents (10% hydrogen peroxide, 0.25% potassium
permanganate) - Melanin in basophilic, positive Schmorl, and argentaffin
- Lipidic pigments: lipofuscin (wear-and-tear) brownish yellow, can be stained with Oil Red O, PAS, and Sudan Black
- Ceroid is brownish yellow pigment
Endogenous Deposits
- Urates are very common, soluble in aqueous solutions.
- Must use alcoholic fixation, and are birefringent
- Minerals such as calcium ferric/ferrous, cupric, and phosphates can be deposited
in tissue
Cytoplasmic Granules
- Adrenal chromaffin cells, pancreatic endocrine cells, gastrointestinal enterochromaffin cells, C cells of the thyroid, and some neuroendocrine cells. (APUD cells).
- Amine precursor uptake and decarboxylation
- Some enteroendocrine cells are examples
- Fixatives are VERY important for these granules (Orth, argentaffin granules in GI are destroyed by alcohol, Paneth cell granules destroyed by acetic acid)
Pigment Stains
◦ Prussian blue
◦ Turnbull blue
◦ Schmorl
◦ Fontana-Masson
◦ Grimelius
◦ Churukian-Schenk
◦ Gomori methenamine silver
◦ Hall (Fouchet)
◦ Von Kossa
◦ Alizarin red S
◦ Rhodanine
◦ Prussian blue
◦ Turnbull blue
◦ Schmorl
◦ Fontana-Masson
◦ Grimelius
◦ Churukian-Schenk
◦ Gomori methenamine silver
◦ Hall (Fouchet)
◦ Von Kossa
◦ Alizarin red S
◦ Rhodanine
Know difference between Ferric Ion
(Fe3+) and Ferrous (Fe2+)
…
Prussian blue
- Demonstrates FERRIC iron in tissues (Fe3+)
- Demonstrates FERRIC iron in tissues (Fe3+)
- Potassium FERROCYANIDE used to detect FERRIC ions
- Idiopathic hemochromatosis
- 10% NBF or alcohol preferred fixative
- Cut at 4-5um
- Section with ferric iron as control
◦ Results:
- Nuclei and hemofuchsin: bright red
- Hemosiderin (iron): blue
- Background: pink
Turnbull blue
- Demonstrates FERROUS iron in tissue (Fe2+)
- Demonstrates FERROUS iron in tissue (Fe2+)
- Potassium FERRICYANIDE detects FERROUS ions in tissue
- (Fe2+)+Potassium Ferricyanide => ferrous ferricyanide (turnbull blue)
- 10% NBF or alcohol preferred fixative
- Cut at 4-5um
- Sections containing ferrous iron must be used
◦ Results:
- Ferrous iron – blue
- Background – pink-re
Schmorl
- Demonstrates reducing substances in tissue. (argentaffin) Melanin, formalin pigment
- Demonstrates reducing substances in tissue. (argentaffin) Melanin, formalin pigment
- Based on Turnbull blue reaction
- 10% NBF preferred fixative
- Cut at 4-5um
- QC must contain melanin or argentaffin granules
◦ Results:
- Reducing substances: blue-green
- Goblet cells, mucin: rose
- Background: yellow-green
Fontana-Masson
- Demonstrates argentaffin substances, carcinoid tumors
and neurosecretory granules
- Demonstrates argentaffin substances, carcinoid tumors and neurosecretory granules
- 10% NBF preferred, alcohol should be avoided
- Cut at 4-5um
- Skin is a good control or appendix
- Gold Chloride
- Other reducing substances such as formalin pigment will be stained
- *HMB-45
- Can use a method similar to digestion- bleach out the
melanin
◦ Results:
- Melanin – black
- Argentaffin granules – black
- Nuclei - pink
Grimelius argyrophil stain
- Demonstrates argyrophil granules in neurosectretory tumors
- Demonstrates argyrophil granules in neurosectretory tumors
- 10% NBF is preferred fixative
- Cut at 4-5um
- Control must have argyrophil-positive carcinoid tumor, or small intestine
- Uses hydroquinone
◦ Results
- Argentaffin granules: dark brown to black
- Argyrophil granules: dark brown to black
- Nuclei: red
Background – pale yellow to brown
