practical 5- staining techniques Flashcards
staining techniques
what is a dye
a salt of an aromatic compound which dissolves in water or aqueous solution to produce coloured ions
what are dyes classified by
their chromophores
what is a chromophore
a colour bearing chemical configuration
what are the 3 types of chromophores
quinonoid
azo
nitro
what is an auxochrome
a radical which infers a charge to the dye (acidic or basic properties to the dye)
why must a dye contain an auxochrome
to speed up the process and prevent the dye from elute when washing
what is a chromogen made up of (true dye)
chromophore and auxochrome
what are the 5 main staining processes used in histology
vital staining elective staining histochemical staining metallic impregnation staining with dyes (general physical and chemical reactions, metachromasia)
what does a H&E stain identify
cell morphology atrophy hypertrophy ectopic calcification inflammation infarction
which stain identifies acidic mucins
what can this stain also be used in combination with
alcian blue 8GX
PAS
what does the PAS (periodic acid schiff) stain identify
neutral mucins
anything containing 1:2 glycol groups
collagen, fungi, basement membrane
what must an amyloid stain be used in conjunction with
polarising microscopy
which stain is most suitable in lipids
lipochromes (elective solubility- oil red O or sudan red dyes)
what does perls (prussian blue) stain identify, what does it also demonstrate
asbestos bodies
demonstrates ferric iron using potassium ferrocyanide in a dilute HCl solution
what are the following stains categorised by
verhoeff, weigert, orcein, millers
elastin stains
which stains uses the silver impregnation technique and is an example of an argyrophillic reaction
reticulin
what does masson fontana identify
melanin
what is meant by an argentaffin reaction
ability to reduce a solution of silver nitrate to metallic silver without the use of an extraneous reducing agent
what is the difference between mason trichome and mallory trichome stain
distinguish collagen from muscle
what does MSB (martius scarlet blue) stain
fibrin
what does the gram stain distinguish between
gram +ve and gram -ve organisms
what does grocott stain
fungi
what does ziehl neelson stain
mycobacterium
what does modified giemsa stain
helicobacter pylori
what does von kossa stain
calcium, ecotopic calcium deposition
how does a metachromatic stain work
1 dye bath produces 2 colours
certain cell constituents can absorb light at 1 wavelength and re-emit light at different wavelength
