Random Flashcards
Hematoxylin is not soluble in alcohol or water, but it is in _________
ethylene glycol
Why is sodium iodate a preferred oxidant for Hx?
Oxidizes at RT
T cell marker
CD3
This dye is linear and stains beta pleated sheets
Congo red
Oxidized product of hematoxylin and its charge
Hematein; negative
3 anionic auxochromes
Sulphonic (SO3-)
Carboxylic (COO-)
Phenolic (O-)
Why is NaOH added to Congo Red
Promotes hydrogen bonds
What is over-oxidized hematoxylin called?
Oxyhematein or isohematein
Consequence of prolonged decalcification on HandE staining?
Poor nuclear detail
What is the charge on all dyes used in trichrome
Anionic
Used to differentiate slides in Verhoeff’s
Ferric chloride
2 fixatives that contain mercuric chloride
Zenker’s (Helly’s)
B5
Trichrome - what does aniline blue stain
Collagen
2 ways to make Hx more selective
- Add more acid
- Apply excess mordant
Dye that stains keratin in PAP method
Orange G
Stain that contains a very large positively charged molecule w/ copper in it
Alcian blue
Anionic group involved in metachromasia
chromotrope
Mordant:hx ratio
35:1
Collagen found in basement membranes
Type IV
Trichrome theory - larger dyes displace smaller dyes in collagen due to ______________
stronger bonding
Oxidizing agent in Harris’ hematoxylin
Mercuric oxide
Main disadvantage of using EDTA as a decalcifying agent?
Extremely slow
This fixative requires the addition of formalin prior to use
B5
Colour of hematein in low and high pH?
Low = red High = blue
Why cool blocks after embedding in molten wax?
Wax will form SMALLER cystals
This tissue element should stain magenta-pink after PAS+D staining
Neutral sugars in colonic goblet cells
Example of a modified leuco dye is found in this method
PAS
2 types of carbohydrates that stain with Alcian blue
Proteoglycans and glycoproteins
May be used to identify neutrophils in a smear or tissue section
Chloroacetate esterase
Eosin has an overall _______ charge and is therefore referred to as an _________ dye (not cationic/anionic)
negative; acidic
Main disadvantage to the use of paraffin wax as an embedding agent?
Limit to section thickness
Dye that stains cytoplasm in PAP method
Eosin azure
The iron hematoxylins made with ferric chloride have a very short shelf life because..?
the ferric chloride oxidizes hematein then to oxyhematein
2 possible consequences of adding acid to dye solutions to promote ionization
- anionic dyes becoming un-ionizes
- dye precipitation
Anhydrous copper sulphate is sometimes added to this to check for presence of water
ethanol (turns blue in presence of water)
Best tissue for HandE control slide
GI tract
What could cause freshly made eosin to precipitate
Too much acid
Example of a neutral dye
Romanowsky-Giemsa
Colourless dye in PAS?
Schiff’s reagent
Mast cells have __________ which allow metachromatic staining
chromotropes
The usual temperature that wax baths are maintained at?
60 degC
Oxidizing agent in Gill’s hematoxylin
Sodium iodate
A suitable marker for B lymphocytes could be
L26/CD20
The major objection for the use of xylene as a clearing agent for processing tissues?
Xylene is likely to harden tissue
