Flashcards
Special stains
Cards in this deck (16)
- 1- Practicalities - controls- ventilated bench with downdraft to keep toxic vapour away,, so risk assessment needed by COSHH
- Usually -ve but when pathological tissue, +ve used - 2Principles of trichome stains- high density tissue have better staining
- More permeable tissue have better staining
- small molecule stains have better penetration - 3E.g. Martius scarlet blue (MSB) stain connective tissue - martius yellow - brilliant crystal scarlet - aniiine blue- small so stains RBC's
- Medium so stains fibrin & muscle
- Large so stains collagen, elastic fibres, basement membrane & reticulin - 4E.g. Haematoxylin & van Gieson stains connective tissue - Haematoxylin (dark blue) - small- picric acid (yellow) - large acid fuchsin (red)- stains nuclei
- stains RBC's & cytoplasm
- collagen - 5Metachromastic dyes and metachromasia - Pure dye of one colour stains a tissue element another colour e.g. toluidine blue- strong basic dye, stains nuclei blue – orthochromasia
- Also stains mast cell granules purple – metachromasia
- these substances are called chromotropes - 6Artefact pigments – not meant to be present in tissues- Formalin pigment (brownish deposit)
- Mercury (dense black), chrome (brownish) and osmium (dense black) pigments - 7Exogenous pigments – present in tissue but as contaminant- Carbon (dense black)
- Silica (brown/black depending on source)
- Asbestos (brown fibres)
- Tattoo pigments - 8Endogenous pigments – made by the tissues - Haematogenous pigments - - Autogenous pigments- 1) Haemoglobin - In FFPE sections haemoglobin appears brownish.
2) Haemosiderin pigments (yellow/brown intracellular granules)
- 1) Melanin – pigment (black/brown)
2) Lipofuchsin – (yellow/brown) - 9e.g. perl's prussian blue stain haemosiderin - why? - What? - property- to detect haemosiderosis & haemochromatosis
- HCl & K4[Fe(CN)6]
HCl + Fe3+ --- FeCl3
- insoluble Prussian blue - 10Asbestosis is a chronic lung conditionAsbestos fibres in lungs become coated with haemosiderin which stain blue with Perls
- 11e.g. schmorl's stains melanin - why? - what?- to detect benign nevus cell tumours & malignant melanomas
- K3[(Fe(CN)6] & FeCl3
- Fe3+ reacts with potassium ferrocyanide to form ferric ferrocyanide - 12e.g. masson-fontana stains melanin Melanin – black Nuclei – red (neutral red stain) Cytoplasm – pinkSilver impregnation via the argentaffin reaction
Melanin reduces ammoniacal silver solution to metallic silver
Stain with Fontana solution - 13extracellular proteins staining e.g. 's - fibrin - collagen - elastin (dark brown/purple) - reticulin - amyloid– Haematoxylin & van Gieson (yellow), MSB (red)
– Haematoxylin & van Gieson (red), MSB (blue)
– Orcein
- Reticulin
– Congo red, Thioflavin T - 14orcein diagnoses hep B- stains copper-associated proteins, linked to liver disease – brown, fine cytoplasmic granules
- stains hepatitis B surface antigen (HBsAg) in viral inclusion bodies, diffuse brown/purple cytoplasmic stain - 15reticulin staining detects fibrosis and cirrhosisReticulin demonstrated using silver impregnation – argyrophil reaction (requires reducing agent)
- 16lysochrome staining Oil red O for neutral lipids- Lipids are not retained during processing of samples through alcohol/xylene to paraffin wax
- Do not dehydrate, clear and mount in DPX (or else you’ll dissolve out all the nicely stained lipid!)
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- BIOL 282 - Cellular pathology Flashcards on Special stains, created by Jumael Zafar on 26/11/2019.
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- Jumael Zafar
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