EMBEDDING

Question 1

process of embedding

Answer 1

infiltrated tissues are precisely positioned/arranged/placed in mold that contains embedding medium which then allowed to solidify

Question 2

types of Blocking-out Molds

Answer 2

LCDP
LEUCKHART’S EMBEDDING MOLD
COMPOUND EMBEDDING UNIT
DISPOSABLE EMBEDDING MOLD
PLASTIC EMBEDDING RING AND BASE MOLD

Question 3

process by which a tissue is arranged in precise positions

Answer 3

Orientation

Question 4

processes req orientation

Answer 4

o Mold during embedding
o Microtome before cutting
o Slide before staining

Question 5

temp for embedding

Answer 5

5-10°C above melting point

Question 6

how to cool embedding

Answer 6

-5°C or immersed in cold water

Question 7

If too soft

Answer 7

torn, shredded sections

Question 8

if too hard

Answer 8

brittle, scattered section

Question 9

what whould e.m match w tissues

Answer 9

strength & hardness

Question 10

consists of two L-shaped strips of heavy brass or metal
arranged on a flat metal plate and which can be moved to adjust the size of the
mold to the size of the specimen

Answer 10

Leuckhart’s
Embedding Mold

Question 11

Blocks produced are even, with parallel sides,
and with a fairly shaped initial setting of the wax

Answer 11

Leuckhart’s
Embedding Mold

Question 12

mold is adjustable to
give a wide variety of sizes to fit the size of the tissue block for casting

Answer 12

Leuckhart’s
Embedding Mold

Question 13

recommended for routine use, although, too slow and cumbersome for use in a
busy laboratory.

Answer 13

Leuckhart’s
Embedding Mold

Question 14

series of interlocking
plates resting on a flat metal base, forming several compartments

Answer 14

Compound Embedding Unit

Question 15

has the advantage of embedding more specimens at a time

Answer 15

Compound Embedding Unit

Question 16

-consist of a special
stainless steel base mold fitted with a plastic embedding ring

Answer 16

Plastic Embedding Rings and Base Mold

Question 17

serves as the block holder during cutting

Answer 17

Plastic Embedding Rings and Base Mold

Question 18

Tissue Tek

Answer 18

white plastic cassette with detachable perforated stainless steel hinge and snap on lid

Question 19

can hold the tissue specimen through-out fixation, dehydration,
clearing and wax impregnation.

Answer 19

Tissue Tek

Question 20

Disposable Embedding Molds

Answer 20

PA
PIT
PB

PEEL-AWAY
PLASTIC ICE TRAYS
PAPER BOATS

Question 21

disposable thin plastic
embedding molds, available in 3 different sizes, are simply peeled off one
at a time

Answer 21

Peel-Away

Question 22

giving perfect even block
without trimming

Answer 22

Peel-Away

Question 23

may be placed directly in the chuck or block holder of
the microtome

Answer 23

Peel-Away

Question 24

Thin plastic embedding molds
- Available in 3 different sizes
- May be placed in the block holder of the
microtome
- These are simply peeled off one at a time, as
soon as the wax has solidified.
- An advantage is giving a perfect even block
without trimming.

Answer 24

Peel Away

Question 25

Same as the ones used in ordinary refrigerator

Answer 25

PLASTIC ICE TRAYS

Question 26

smearing the inner mold with glycerin or liquid paraffin before embedding

Answer 26

Plastic Ice Trays

Question 27

utilized for embedding celloidin blocks but are equally useful for paraffin wax blocks

Answer 27

Paper Boats

Question 28

advantage of being cheap and easy to make

Answer 28

Paper Boats

Question 29

provide easy and accurate identification of specimen, thereby avoiding confusion and interchange of tissue blocks

Answer 29

Paper Boats

Question 30

Margin of paraffin surrounding the tissue

Answer 30

2mm

Question 31

Rapid embedding of small & large volume of tissue

Answer 31

paper boat

Question 32

can be made to suit any size of tissue

Answer 32

paper boat

Question 33

medium used for paper boat

Answer 33

Stainless steel, ceramic, paper, plastic, and aluminum foil

Question 34

recommended for embedding hard tissues such as bones and teeth, and for large sections of whole organs like the eye

Answer 34

Celloidin or Nitrocellulose Embedding Method

Question 35

Tissues are embedded in shallow tins of enamel pans which are covered by sheets of weighted glass

Answer 35

Celloidin or Nitrocellulose Embedding Method

Question 36

Bell jars

Answer 36

used to control the rate or evaporation of the solvent

Question 37

why does the use of celloidin is already discouraged

Answer 37

discouraged now because of the special requirements needed for processing and the limited use of these types of sections in neuropathology

Question 38

double embedding

Answer 38

the process by which tissues are first embedded or fully infiltrated with a supporting medium such as agar or nitrocellulose. • Then, it is infiltrated for a second time with paraffin wax in which they are subsequently embedded. - 1st embedding: agar or nitrocellulose 2nd embedding: paraffin wax

Question 39

disadv of double embedding (agar)

Answer 39

- Tissue shrinkage during embedding process - Failure to expand during slide mounting - Obsolete

Question 40

Provides superior results for light microscopy

Answer 40

PLASTIC (RESIN) EMBEDDING

Question 41

Classification of plastic embedding

Answer 41

PEA POLYESTER EPOXY ACRYLIC

Question 42

specimens of plastic embedding

Answer 42

hard tissue (undecalcified) 4-6 um thin tisues (renal & BM biopsy)

Question 43

Originally introduced for EM (1950s) Have been superseded by more superior epoxides, and are now seldom used

Answer 43

POLYESTER

Question 44

mixture of epoxy

Answer 44

Epoxy plastic + catalyst + accelerators

Question 45

Epoxy plastic + catalyst + accelerators types

Answer 45

SEA ARALDITE (BISPHENOL A) EPON (GLYCEROL-BASED) SPURR (CYCLOHEXENE DIOXIDE-BASED)

Question 46

compatible with ethanol so no change to propylene oxide is needed prior to infiltration.

Answer 46

spurr

Question 47

Slow because of it being plastic (large molecule)

Answer 47

Araldite (Bisphenol A)

Question 48

Lower viscosity but often sold as mixture of isomers

Answer 48

epon

Question 49

Can be obtained pure, have very low viscosity & infiltrate faster; Compatible with ethanol (no change needed for propylene oxide); Polymerization at 60’C

Answer 49

Spurr (cyclohexene dioxide-based)

Question 50

disadv of epoxy

Answer 50

HOST A HYDROPHOBIC OXIDIZES W PEROXIDE SENSITIZATION VIA SKIN & INHALATION TOXIC (VINYL CYCLOHEXANE DIOXIDE) ANTIGENICITY-IHC

Question 51

Made up of esters of acrylic or methacrylic acid

Answer 51

ACRYLIC PLASTICS

Question 52

ACRYLIC PLASTICS

Answer 52

PMH

Question 53

used extensively for light microscopy

Answer 53

ACRYLIC PLASTICS

Question 54

popular embedding medium for light microscopy

Answer 54

Polyglycol methacrylate

Question 55

extremely hydrophilic, allowing many staining methods to be applied, yet tough enough when dehydrated to section well on most microtomes

Answer 55

Polyglycol methacrylate

Question 56

polar water soluble

Answer 56

2-hydroxyethyl methacrylate, commonly known as "glycol methacrylate", or GMA

Question 57

embedding of biological tissue for transmission electron microscopy (TEM)

Answer 57

Hydroxyethyl methacrylate or "glycol methacrylate" (GMA)

Question 58

Fine structure not previously subjected to solvent dehydration

Answer 58

Hydroxyethyl methacrylate or "glycol methacrylate" (GMA)

Question 59

preservation and observation of fine structure not previously subjected to solvent dehydration

Answer 59

Hydroxyethyl methacrylate or "glycol methacrylate" (GMA)

Question 60

forms only non-crosslinked straight chains on polymerization and therefore requires no hardener

Answer 60

GMA

Question 61

Dehydration of tissues can be made directly in ________ or optionally in organic solvents.

Answer 61

aqueous dilutions of GMA

Question 62

adv of gma

Answer 62

DARE FTW

Question 63

Ideal embedding medium for undecalcified bone

Answer 63

Methyl methacrylate (MMA)

Question 64

Used for bone histomorphometry & BM hematopathology

Answer 64

Methyl methacrylate (MMA)

Question 65

adv of mma

Answer 65

better penetration than GMA - plastic removal from tissue sections (results in superior staining characteristics and excellent morphological detail)

Question 66

dadv of mma

Answer 66

Complete loss of enzymes activity & protein antigenicity → not recommended for histochemical & immunohistological methods