Fichas
Staining
Fichas del conjunto (15)
- 1Types - non-vital - histochemical - lysochrome - Ag impregnation - immunostaining- dead tissue staining
- reaction to detect functional group
- neutral lipid staining
- structures coated with Ag/AgO
- immunocytochemistry - 2dyes requirement. - Chromophore - auxochrome- forms organic coloured compound e.g. NO2, azo or quinonoid groups
- forms ionic bonding with tissue e.g. OH & NH2 groups - 3mechanisms of staining 1. direct- form bonds with tissue.
- ionic bonding is the most important - 42. indirect using a mordant- dye binds mordant which binds tissue e.g. Haematoxylin plus ammonium alum produces a blue lake (alum haematoxylin)
- 53. differentiation- using mordants e.g. dye binds correct mordant
- using acids e.g. acid alcohol breaks bonds
- using oxidizing agent e.g. dye oxidized to non staining compound - 64. differential actionDepth of colouration is affected by
- chemical affinity
- tissue density
- tissue permeability and molecular size of dye - 7H&E - Haematoxylin oxidized to haematein (the dye) - Eosin (counterstain)- mordant = Al salt to form haemalum
Acid conditions – alum dye lake – soluble, red. Alkaline conditions – alum dye lake – less soluble, blue
- provides good info about cell morphology and general topography - 8Special stains - Histochemistry requirements- form coloured product
- produces insoluble in situ product
- be highly sensitive
- Detect substance being investigated in the context of its tissue environment - 9mucins - neutral - sialomucins (weakly acidic) - sulfomucins (strongly acidic)- uncharged monosaccharides – mannose, galactose found in stomach, bronchus etc.
- contain nine-carbon sialic acid monosaccharides at the end of carbohydrate chains distal to protein
- has carb bound SO4^2- groups - 10carb staining 1. PAS technique has 2 steps- Oxidation of sugar molecule to form two aldehyde branches
- Aldehyde groups react with colourless Schiffs reagent to form magenta coloured end product - 11PAS (stains all carbs) useReactivity of Schiff reagent with glycoproteins within the basal lamina makes PAS technique valuable means of assessing basement membrane thickness
- 122. diastase (alpha and B amylase)/PAS techniqueComparing PAS stained section with diastase pre-treated PAS stained section allows specific identification of glycogen in tissue
- 133. Alcian blue staining (positively charged basic copper phthalocyanine dye)- can be fine tuned to be selective for different classes of acid mucins by varying pH for staining.
- At pH 2.5 all acid mucins stain with Alcian blue
- At pH 1 only strongly sulphated mucins stain with Alcian blue - 144. 4. Combined Alcian blue/PAS for mucin- PAS stains neutral mucins (and glycogen).
- Can be combined with optional use of diastase prior to staining (eliminates glycogen) - 15why stain carbs? for diganosis- glycogen storage abnormalities
- tumours by mucin or glycogen
- fungal infection by fungi carbs
- basement membrane abnormalities
Información
- Descripción
- BIOL 282 - Cellular pathology Fichas sobre Staining, creado por Jumael Zafar el 19/11/2019.
- Creado por
- Jumael Zafar · nov 2019
- Actualizado
- 19 nov 2019
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