WAX IMPREGNATION AND EMBEDDING Flashcards
replacing the clearing agent with the infiltrating medium to fill all tissue cavities
impregnation
impregnation aka
inlfiltration
embedding aka
casting
impregnated tissue is placed into a precisely arrange position in a mold containing an embedding medium and allowed to solidify
embedding
types of impregnating and embedding media
- paraffin
- celloidin
- gelatin
- plastic
simplest, most common, best embedding medium
paraffin
paraffin melting point for routine work
56C
overheated paraffin temp
> 60C
four changes of paraffin wax at 15 minute intervals
manual processing of paraffin wax impregnation
use of automatic tissue processor
automatic manual processing of paraffin wax impregnation
specimens are transferred from container to container to be processed
tissue-transfer (dip and dunk)
specimens are held in a in a single process chamber or retort; fluids are pumped in and out
fluid transfer
number of stations
12 station (10 1 liter containers) and 2 wax baths
wax bath thermostat
30C higher that melting point of wax
steps in autotechnicon
- stations 1 and 2: 10% formalin
- stations 3-6: increasing grades of 70-95% ethanol
- stations 7-8: acetone
- stations 9-10: chloroform or xylene
- stations 11-12: liquid paraffin
wax impregnation under negative atmospheric pressure inside an embedding oven
vacuum embedding
fastest method; for urgent biopsies , delicate tissues, CNS tissues
vacuum embedding
ano gagawin sa autotechnicon pag brown out?
do nothing; it has its spare/back up battery
reusing of paraffin wax can only done ______
twice
water in the wax must be removed by
heating the wax at 100-105C
mixture of paraffin and synthetic plastic polymer
paraplast (parang pellets)
semisynthetic; used for embedding of eyes
bioloid (dalawang O parang dalawang eyes)
wax that contains rubber
tissue mat
water insoluble but soluble in 95% ethanol
ester wax
most common polyethylene glycols
carbowax
purified from of nitrocellulose
celloidin
for specimens with large hollow cavities which tend to collapse, hard, and dense tissues
celloidin
makes the tissue blocks rubbery
celloidin
celloidin for bone, brain section, teeth
wet celloidin
celloidin for processing for whole eye section
dry celloidin
preferred celloidin since it produces a harder tissue block and thinner sections are possible
nitrocellulose Method
not a wax; rarely used; for histochemical and enzyme studies and frozen sections
gelatin
done after wax impregnation
embedding
orientation for embedding
surface of the section to be cut should be parallel to the bottom of the mold
tubular structures (arteries, fallopian tubes)
cut in X section of the lumen
skin, intestine, gall bladder and other epithelial biopsies
cut in a plane at right angles to the surface
muscle biopsies
transverse and longitudinal planes
2 L shaped strips of heavy brass or metal; size is adjustable
Leuckhart’s embedding mold
made of grids or compartment; multiple embedding
compound embedding unit
special stainless steel base mold fitted with a plastic embedding ring
plastic embedding rings and base molds
peel away
disposable molds (e.g. ice tray, paper boat
for hard tissues and large sections of whole organs
celloidin and nitrocellulose method
1st infiltration with celloidin and subsequently embedded with paraffin
double embedding method
for extremely hard tissues
plastic (resin) embedding
not recommended for immunohistochem since it reduces the antigenicity of the sample
epoxy
most stable embedding choice for TEM
bisphenol A
