Impregnation Flashcards
Ideal volume
25x
3 ways of paraffin wax impregnagion
1) Manual
2) Automatic
3) Vacuum
Requires 4 changes with 15 mins interval
Manual processing
Makes use of an automatic tissue processing machine resulting in a more rapid diagnosis with less technicality
Automatic processing
Impregnation under negative pressure; for urgent biopsies and delixate tissues; most rapid
Vacuum
Simplest; most common; best for routine use; mp = 54-58 degC
Paraffin wax
Mixture of highly purified paraffin wax and synthetic plastic polymers; more elastic and more resilient; mp: 56-57 degC
Paraplast
Similar to paraplast but less brittle and less compressible; mp: 56-58 degC
Embeddol
Semi-synthetic wax recommended for embedding eyes
Bioloid
Harder than paraffin; not soluble in water but soluble in 94% ethanol and other clearjng agents; mo: 46-48 degC
Ester wax
Mostly polyethylene glycols with mp of 38-42 degC or 45-56 degC
Water soluble waxes
Most commonly used polyethylene glycol which appears solid at RT; soluble in water, hemce does not require dehydration and clearing; for enzyme histochemical studies
Carbowax
Purified form of nitrolcellulose; soluble in many solvents; for specimens containg large cavities or hollow spaces; for hard and dense tossues; for large sections of whole embryos; less shrinkage and distortion
Celloidin
Recommended for bones, teeth, large brain sections and whole organs; must be cut wet (both knife and tissue are kept moist with 70% alcohol)
Wet celloidin method
For processing of whole eye sections; can be cut without alcohol due to presence of cedarwood oil
Dry celloidin method
Mixture used in dry celloidin method; equal parts of chloroform and cedarwood oil
Gilson’s mixture
Another form of celloidin that is soluble in equal concentration of ether and alcohol
Low viscosity nitrocellulose
Used when dehydration is to be avoided; used for histochemical and enzyme studies; for delicate specimens and frozen sections; does not require dehydration and clearing
Gelatin impregnation
