[2S] UNIT 7 Impregnation and Embedding

Question 1

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.

Answer 1

Impregnation

Question 2

A suitable embedding mold is filled with the molten wax, the tissue is placed in it and oriented so it is sectioned in the proper plane.

Answer 2

Embedding

Question 3

T/F: Wax to be used for embedding must contain trace of clearing agent, dust particles, and must be rapidly cooled to reduce the wax crystal size.

Answer 3

F; must not contain trace of clearing agent

Question 4

A variety of molds can be used depending on the technician’s preference

Answer 4

Embedding

Question 5

TECHNIQUES FOR EMBEDDING TISSUES

Transfer the tissue with _____ forceps to a small container of freshly melted paraffin

Answer 5

warm

Question 6

TECHNIQUES FOR EMBEDDING TISSUES

T/F: All parts of the forceps are heated in an alcohol lamp or in a forceps warmer, tips should be hot enough so paraffin does not solidify, but not so hot as to cause paraffin to smoke

Answer 6

F; only the tips are heated

Question 7

TECHNIQUES FOR EMBEDDING TISSUES

Fill the bottom of the mold with a small amount of paraffin. The depth of the mold should be at least ______ the thickness of the tissue.

Answer 7

twice

Question 8

TECHNIQUES FOR EMBEDDING TISSUES

T/F: Pick up tissue, and place into the mold. Manipulation of the tissue in the mold must be slow, so paraffin does not begin to harden.

Answer 8

F; must be quick

Question 9

TECHNIQUES FOR EMBEDDING TISSUES

After tissue is in the mold, fill mold entirely with the paraffin. As the paraffin begins to harden insert a _____ ________ label; the label should not go down to the bottom of the paraffin

Answer 9

code number

Question 10

TECHNIQUES FOR EMBEDDING TISSUES

After the paraffin block hardens, where do we immerse the mold to hasten solidification of the paraffin?

Answer 10

Into a shallow, cool (10C) water bath, 10-15 mins

Question 11

TECHNIQUES FOR EMBEDDING TISSUES

T/F: When paraffin is soft, remove it from the mold.

Answer 11

F; When paraffin is completely hardened, remove it from the mold.

Question 12

T/F: If paraffin is properly cooled, the crystals of paraffin are small and contiguous with each other.

Answer 12

T

Question 13

Temperature that prevents cracking of the tissue block

Answer 13

10˚C

Question 14

COOLING TEMP

T/F: The paraffin will appear clear and homogeneous and there is no layering of the paraffin. Paraffin demonstrating these conditions is best for sectioning.

Answer 14

T

Question 15

Specimen should be embedded and oriented in the center in a manner that it would be surrounded ___ by paraffin on all sides

Answer 15

2 mm

Question 16

Ideally, the medium should be soluble in processing fluids. It should be easy to section and make ribbons, molten between ______ C

Answer 16

30 to 60 degrees Celsius

Question 17

Translucent or transparent, stable, homogenous, capable of flattening after ribboning, non-toxic, odorless, easy to handle, and inexpensive

Answer 17

Embedding medium

Question 18

EMBEDDING MEDIUM

T/F: The properties of the medium should nearly match those of the tissues to be sectioned and should be inert to the embedded material

Answer 18

T

Question 19

rapidly converted from solid to liquid form on heating

Answer 19

Paraffin

Question 20

solidifies relatively quickly on cooling

Answer 20

Paraffin

Question 21

permeates the tissue in a liquid state

Answer 21

Paraffin

Question 22

becomes fluid on heating to a temperature which will not damage the tissue

Answer 22

Paraffin

Question 23

when the paraffin solidifies it becomes firm enough to section at _____ _______

Answer 23

room temperature

Question 24

ADVANTAGES

Time of infiltration and subsequent embedding are relatively short for small pieces of tissue.

Answer 24

Paraffin

Question 25

ADVANTAGES Thin sections can be cut with the rotary microtome and sections will adhere to each other to form a ribbon.

Answer 25

Paraffin

Question 26

ADVANTAGES Tissue once infiltrated and embedded can be stored in a dry condition indefinitely without damage to the tissue.

Answer 26

Paraffin

Question 27

- highly purified paraffin waxes with DMSO (dimethylsulfoxide) - elastic & resilient

Answer 27

Ester Wax

Question 28

5 Substitute Of Paraffin Waxes

Answer 28

* Paraplast * Fibrowax * Bioloid * Embeddol * Ester Wax

Question 29

mixture of highly purified paraffin and synthetic plastic polymers

Answer 29

Paraplast

Question 30

It is less brittle and less compressible than Paraplast.

Answer 30

Embeddol

Question 31

is a semisynthetic wax recommended for embedding eyes

Answer 31

Embeddol: Bio/aid

Question 32

has a lower melting point (46-48°C), but it is harder than paraffin.

Answer 32

Ester Wax

Question 33

with melting points of 38-42°C or 45-56°C

Answer 33

Water Soluble Waxes

Question 34

It is not soluble in water, but is soluble in 95% Ethyl Alcohol and other clearing agents

Answer 34

Ester Wax

Question 35

A polyethylene glycol is suitable for many enzyme histochemical studies. Cytologic details are excellently preserved

Answer 35

Water Soluble Waxes: Carbowax

Question 36

DISADVANTAGES Distortion of the histology of the tissue due to shrinkage may occur, especially when sections are being attached to glass slides

Answer 36

Paraffin (paraffin artifact)

Question 37

Histotechnologist may experience an unpleasant and annoying oyster or garlic taste

Answer 37

Dimethyl sulphoxide (DMSO)

Question 38

DISADVANTAGES sectioning of paraffin is difficult at high temperatures.

Answer 38

Paraffin

Question 39

DISADVANTAGES Time for infiltration of large blocks of tissue is excessive.

Answer 39

Paraffin

Question 40

amorphous, slightly yellowish substance

Answer 40

Celloidin

Question 41

- purified form of collodion or nitro-cellulose - for hard tissue specimens

Answer 41

Celloidin

Question 42

ADVANTAGES Does not require heat

Answer 42

Celloidin

Question 43

ADVANTAGES minimal distortion of specimen

Answer 43

Celloidin

Question 44

ADVANTAGES Has a rubbery consistency

Answer 44

Celloidin

Question 45

DISADVANTAGES difficult to cut thin sections

Answer 45

Celloidin

Question 46

DISADVANTAGES Serial sections are difficult to prepare

Answer 46

Celloidin

Question 47

DISADVANTAGES ● Slow process ● Blocks and sections must be stored in 70% alcohol otherwise, they become discolored, dry, and shrunken

Answer 47

Celloidin

Question 48

Recommended for bones, teeth, large brain sections and whole organs

Answer 48

Wet Celloidin

Question 49

Preferred processing of whole eye sections

Answer 49

Dry Celloidin

Question 50

Another form of celloidin soluble in equal concentration of ether and alcohol, with a lower viscosity, allowing it to be used in higher concentrations and still penetrates tissue rapidly

Answer 50

Low Viscosity Nitrocellulose (LVN)

Question 51

It forms a harder tissue block and making cutting of thinner sections possible

Answer 51

Low Viscosity Nitrocellulose (LVN)

Question 52

More explosive than celloidin

Answer 52

Low Viscosity Nitrocellulose (LVN)

Question 53

ADVANTAGES Low viscosity; allows higher concentration to be used

Answer 53

Low Viscosity Nitrocellulose (LVN)

Question 54

● Used in dealing with hard tissues ● For maintenance of the morphological appearance of the tissue

Answer 54

Double Embedding

Question 55

ADVANTAGES ● Greater speed of impregnation ● Final block is harder, allowing thinner sections to be cut

Answer 55

Low Viscosity Nitrocellulose (LVN)

Question 56

ADVANTAGES Has a greater water tolerance than celloidin

Answer 56

Low Viscosity Nitrocellulose (LVN)

Question 57

DISADVANTAGES ● Have a tendency to crack down during handling and staining ● Highly explosive

Answer 57

Low Viscosity Nitrocellulose (LVN)

Question 58

LVN has the tendency to crack down during handling and staining. How do we minimize this tendency?

Answer 58

Use 0.5% Oleum Ricini (Castor Oil)

Question 59

Tissue is first impregnated with celloidin, and subsequently blocked in paraffin wax

Answer 59

Double Embedding

Question 60

● Serial sections are easily prepared ● Extra degree of resilience is given when cutting hard tissues

Answer 60

Double Embedding

Question 61

DOUBLE EMBEDDING Cohesive agent for multiple fragments or friable tissue

Answer 61

Agar

Question 62

DOUBLE EMBEDDING Main use is in double embedding technique with ester wax or paraffin wax

Answer 62

Agar

Question 63

DOUBLE EMBEDDING ● Has a lower melting point than agar ● Main use in the production of whole organ sections ● For friable tissues

Answer 63

Gelatin

Question 64

DOUBLE EMBEDDING ● Tissue can be embedded directly from water ● However, it is restricted, due to the violent diffusion currents which can lead to the complete fragmentation of the section

Answer 64

Water-Soluble Waxes

Question 65

PLASTIC EMBEDDING MEDIUM ○ Used extensively for light microscopy ○ Methyl methacrylate (MMA) ○ Polyglycol methacrylic (GMA)

Answer 65

Acrylic

Question 66

PLASTIC EMBEDDING MEDIUM Not often used

Answer 66

Polyester

Question 67

PLASTIC EMBEDDING MEDIUM ○ Reduces antigenicity, toxic, and damages tissue ○ Bisphenol A (Araldite), or Glycerol (Epon), or Cyclohexene dioxide (Spurr)

Answer 67

Epoxy

Question 68

MOLDS FOR EMBEDDING Molds for routine work and are widely used

Answer 68

LEUCKHART’S EMBEDDING MOLD

Question 69

MOLDS FOR EMBEDDING Consist of 2 L-shaped pieces of metal

Answer 69

LEUCKHART’S EMBEDDING MOLD

Question 70

MOLDS FOR EMBEDDING Arranged on a glass metal plate to form a mold of desired size

Answer 70

LEUCKHART’S EMBEDDING MOLD

Question 71

MOLDS FOR EMBEDDING Consists of a series of interlocking plates resting on a flat metal base, forming several compartments

Answer 71

COMPOUND EMBEDDING UNIT

Question 72

MOLDS FOR EMBEDDING Has the advantage of embedding more specimens at a time

Answer 72

COMPOUND EMBEDDING UNIT

Question 73

MOLDS FOR EMBEDDING Used in positioning histological tissues accurately in base molds

Answer 73

PLASTIC EMBEDDING RING AND BASE MOLD

Question 74

MOLDS FOR EMBEDDING Compatible with most commonly used processing and storage systems

Answer 74

PLASTIC EMBEDDING RING AND BASE MOLD

Question 75

MOLDS FOR EMBEDDING Rings are precision-molded from premium-grade, chemically inert, high-impact polystyrene for dimensional rigidity and sturdiness

Answer 75

PLASTIC EMBEDDING RING AND BASE MOLD

Question 76

MOLDS FOR EMBEDDING ● With more efficient outcomes, just place the tissue and the embedding mold ● Reusable

Answer 76

POP-OUT EMBEDDING MOLD

Question 77

MOLDS FOR EMBEDDING For single tissue block outcomes/outputs only

Answer 77

POP-OUT EMBEDDING MOLD

Question 78

MOLDS FOR EMBEDDING Once the wax has solidified, the plastic walls are peeled off one at a time, giving perfect blocks that require no trimming

Answer 78

DISPOSABLE EMBEDDING MOLD: Peel-a-way

Question 79

MOLDS FOR EMBEDDING Cheap to make and allow blocks to be stored without being removed

Answer 79

PAPER BOAT

Question 80

MOLDS FOR EMBEDDING They can be placed directly in the chuck of the microtome

Answer 80

DISPOSABLE EMBEDDING MOLD: Peel-a-way

Question 81

MOLDS FOR EMBEDDING Convenient molds for busy routine laboratory, one block being embedded in each compartment

Answer 81

PLASTIC ICE TRAY

Question 82

MOLDS FOR EMBEDDING Made from thick paper or cardboard paper

Answer 82

PAPER BOAT

Question 83

MOLDS FOR EMBEDDING Provide easy and accurate identification of specimens, thereby avoiding confusion and interchange of tissue blocks

Answer 83

PAPER BOAT

Question 84

MOLDS FOR EMBEDDING Blocks are easily removed by flexing the plastic trays and by smearing the inside of the mold with glycerin or liquid paraffin

Answer 84

PLASTIC ICE TRAY

Question 85

MOLDS FOR EMBEDDING T/F: Plastic ice tray is not usually used but some may use this to orient the tissue

Answer 85

T

Question 86

MOLDS FOR EMBEDDING ● Ideal for embedding fragmentary biopsies ● Not essential to smear them with glycerin ● However, blocks are hard to remove

Answer 86

WATCH GLASSES

Question 87

MOLDS FOR EMBEDDING Used for small fragments that have been processed (e.g. Bone marrow) which concentrates them without the damage caused by orientation with forceps

Answer 87

TEST TUBES

Question 88

MOLDS FOR EMBEDDING Used for embedding tissue intended for EM microscopy

Answer 88

METHACRYLATE PLASTIC RESIN (EPON RESIN)

Question 89

MOLDS FOR EMBEDDING Disadvantage: often necessary to break the tube to remove the block

Answer 89

TEST TUBES

Question 90

T/F: Low viscosity Nitrocellulose (LVN) is highly explosive.

Answer 90

T

Question 91

T/F: blocks are easily removed by smearing the inside of the mold with glycerin.

Answer 91

T

Question 92

T/F: Tissues should not reach the edges during embedding.

Answer 92

T

Question 93

T/F: Cellosolve is used as an embedding medium.

Answer 93

F; Cellosolve is a dehydrating agent

Question 94

T/F: Test tubes are one of the possible embedding molds.

Answer 94

T

Question 95

T/F: After embedding, 10 ̊C temperature prevents cracking of the tissue block.

Answer 95

T