02 Embedding and Impregnation Flashcards
___C temperature prevents cracking of the tissue block
10C
a process of saturating the tissue with a medium, usually liquid paraffin, to permeate or fill up the natural cavities, spaces, and interstices of the tissue
impregnation
in embedding, the paraffin should appear ___ and ___ and no layering should be formed
clear
homogenous
paraffin rapidly converts from solid to liquid at ___C
56-58C
type of paraffin wax:
amorphous, slightly yellowish substance
celloidin
the less purified form of celloidin
collodion or nitro-cellulose
T/F: celloidin does not require heat
T
describe the consistency of celloidin
rubbery
substitute for paraffin wax:
mixture of highly purified paraffin and synthetic plastic polymers
paraplast
substitute for paraffin wax:
less brittle and less compressible than paraplast
embeddol
substitute for paraffin wax:
a semisynthetic wax recommended for embedding eyes
bioloid
substitute for paraffin wax:
has a lower melting point (46-48C), but is harder than paraffin
ester wax
substitute for paraffin wax:
not soluble in water, but is soluble in 95% ethyl alcohol and other clearing agents
ester wax
melting point of water soluble waxes
38-42C or 45-46C
substitute for paraffin wax:
a polyethylene glycol is suitable for many enzyme histochemical studies
carbowax
in using dimethyl sulphoxide, histotechnologists may experience an unpleasant and annoying ___ or ___ taste
oyster
garlic
T/F: sectioning of paraffin is difficult at low temperatures
F (high)
type of paraffin wax:
allows higher concentration to be used; greater speed of impregnation
low viscosity nitrocellulose (LVN)
type of paraffin wax:
final block is harder, allowing thinner sections to be cut
low viscosity nitrocellulose (LVN)
type of paraffin wax:
have a tendency to crack down during handling and staining; highly explosive
low viscosity nitrocellulose (LVN)
in double embedding, the tissue is first impregnated with ___, and subsequently blocked in ___
celloidin
paraffin wax
this provides extra degree of resilience when cutting hard tissues
double embedding
type of paraffin wax:
main use is in double embedding technique with ester wax or paraffin wax
agar
type of paraffin wax:
cohesive agent for multiple fragments or friable tissue
agar
type of paraffin wax:
has a lower melting point than aga
gelatin
type of paraffin wax:
main use in the production of whole organ sections
gelatin
type of paraffin wax:
tissues can be embedded directly from water
water-soluble waxes
type of paraffin wax:
restricted due to the violent diffusion currents which can lead to the complete fragmentation of the section
water-soluble waxes
plastic embedding medium:
reduces antigenicity, toxic, and damages tissue
epoxy
epoxy:
bisphenol A
araldite
epoxy:
glycerol
epon
epoxy:
cyclohexene dioxide
spurr
plastic embedding medium:
not often used
polyester
plastic embedding medium:
used extensively for light microscopy
acrylic
mold for embedding:
molds for routine work and are widely used
leuckhart’s embedding mold
mold for embedding:
consists of 2 L-shaped pieces of metal
leuckhart’s embedding mold
mold for embedding:
arranged on a glass metal plate to form a mold of desired size
leuckhart’s embedding mold
mold for embedding:
consist of a series of interlocking plates resting on a flat metal base, forming several compartments
compound embedding unit
mold for embedding:
has the advantage of embedding more specimens at a time
compound embedding unit
mold for embedding:
used in positioning histological tissues accurately in base molds
plastic embedding ring and base mold
mold for embedding:
disposable embedding mold
peel-a-way
mold for embedding:
can be placed directly in the chuck of the microtome
peel-a-way
mold for embedding:
made from thick paper or cardboard paper
paper boat
mold for embedding:
cheap to make and allow blocks to be stored without being removed
paper boat
mold for embedding:
provide easy and accurate identification of specimens, thereby avoiding confusion and interchange of tissue blocks
paper boat
mold for embedding:
convenient molds for busy routine laboratory, one block being embedded in each compartment
plastic ice tray
in using plastic ice tray, blocks are easily removed by flexing the plastic trays and by smearing the inside of the mold with ___ or ___ ___
glycerin
liquid paraffin
mold for embedding:
ideal for embedding fragmentary biopsies
watch glass
T/F: in using watch glass, it is essential to smear with glycerin as the blocks would be hard to remove
F (no need to smear)
mold for embedding:
used for small fragments which have been processed (bone marrow) which concentrates them without the damage caused by orientation with forceps
test tube
mold for embedding:
used for embedding tissue intended for EM microscopy
methacrylate plastic resin (EPON resin)