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[MT 6321] Histopathology Laboratory > [2S] UNIT 7 Impregnation and Embedding > Flashcards

[2S] UNIT 7 Impregnation and Embedding Flashcards

1
Q

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.

A

Impregnation

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2
Q

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.

A

Embedding

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3
Q

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.

A

F; must not contain trace of clearing agent

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4
Q

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

A

Embedding

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5
Q

TECHNIQUES FOR EMBEDDING TISSUES

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

A

warm

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6
Q

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

A

F; only the tips are heated

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7
Q

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.

A

twice

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8
Q

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.

A

F; must be quick

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9
Q

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

A

code number

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10
Q

TECHNIQUES FOR EMBEDDING TISSUES

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

A

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

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11
Q

TECHNIQUES FOR EMBEDDING TISSUES

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

A

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

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12
Q

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

A

T

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13
Q

Temperature that prevents cracking of the tissue block

A

10˚C

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14
Q

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.

A

T

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15
Q

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

A

2 mm

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16
Q

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

A

30 to 60 degrees Celsius

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17
Q

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

A

Embedding medium

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18
Q

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

A

T

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19
Q

rapidly converted from solid to liquid form on heating

A

Paraffin

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20
Q

solidifies relatively quickly on cooling

A

Paraffin

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21
Q

permeates the tissue in a liquid state

A

Paraffin

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22
Q

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

A

Paraffin

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23
Q

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

A

room temperature

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24
Q

ADVANTAGES

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

A

Paraffin

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25
Q

ADVANTAGES

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

A

Paraffin

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26
Q

ADVANTAGES

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

A

Paraffin

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27
Q
  • highly purified paraffin waxes with DMSO
    (dimethylsulfoxide)
  • elastic & resilient
A

Ester Wax

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28
Q

5 Substitute Of Paraffin Waxes

A
  • Paraplast
  • Fibrowax
  • Bioloid
  • Embeddol
  • Ester Wax
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29
Q

mixture of highly purified paraffin and synthetic plastic polymers

A

Paraplast

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30
Q

It is less brittle and less compressible than Paraplast.

A

Embeddol

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31
Q

is a semisynthetic wax recommended for embedding eyes

A

Embeddol: Bio/aid

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32
Q

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

A

Ester Wax

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33
Q

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

A

Water Soluble Waxes

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34
Q

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

A

Ester Wax

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35
Q

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

A

Water Soluble Waxes: Carbowax

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36
Q

DISADVANTAGES

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

A

Paraffin (paraffin artifact)

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37
Q

Histotechnologist may experience an unpleasant and annoying oyster or garlic taste

A

Dimethyl sulphoxide (DMSO)

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38
Q

DISADVANTAGES

sectioning of paraffin is difficult at high temperatures.

A

Paraffin

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39
Q

DISADVANTAGES

Time for infiltration of large blocks of tissue is excessive.

40
Q

amorphous, slightly yellowish substance

41
Q
  • purified form of collodion or nitro-cellulose
  • for hard tissue specimens
42
Q

ADVANTAGES

Does not require heat

43
Q

ADVANTAGES

minimal distortion of specimen

44
Q

ADVANTAGES

Has a rubbery consistency

45
Q

DISADVANTAGES

difficult to cut thin sections

46
Q

DISADVANTAGES

Serial sections are difficult to prepare

47
Q

DISADVANTAGES

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

48
Q

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

A

Wet Celloidin

49
Q

Preferred processing of whole eye sections

A

Dry Celloidin

50
Q

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

A

Low Viscosity Nitrocellulose (LVN)

51
Q

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

A

Low Viscosity Nitrocellulose (LVN)

52
Q

More explosive than celloidin

A

Low Viscosity Nitrocellulose (LVN)

53
Q

ADVANTAGES

Low viscosity; allows higher concentration to be used

A

Low Viscosity Nitrocellulose (LVN)

54
Q

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

A

Double Embedding

55
Q

ADVANTAGES

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

A

Low Viscosity Nitrocellulose (LVN)

56
Q

ADVANTAGES

Has a greater water tolerance than celloidin

A

Low Viscosity Nitrocellulose (LVN)

57
Q

DISADVANTAGES

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

A

Low Viscosity Nitrocellulose (LVN)

58
Q

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

A

Use 0.5% Oleum Ricini (Castor Oil)

59
Q

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

A

Double Embedding

60
Q

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

A

Double Embedding

61
Q

DOUBLE EMBEDDING

Cohesive agent for multiple fragments or friable tissue

62
Q

DOUBLE EMBEDDING

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

63
Q

DOUBLE EMBEDDING

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

64
Q

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

A

Water-Soluble Waxes

65
Q

PLASTIC EMBEDDING MEDIUM

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

66
Q

PLASTIC EMBEDDING MEDIUM

Not often used

67
Q

PLASTIC EMBEDDING MEDIUM

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

68
Q

MOLDS FOR EMBEDDING

Molds for routine work and are widely used

A

LEUCKHART’S EMBEDDING MOLD

69
Q

MOLDS FOR EMBEDDING

Consist of 2 L-shaped pieces of metal

A

LEUCKHART’S EMBEDDING MOLD

70
Q

MOLDS FOR EMBEDDING

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

A

LEUCKHART’S EMBEDDING MOLD

71
Q

MOLDS FOR EMBEDDING

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

A

COMPOUND EMBEDDING UNIT

72
Q

MOLDS FOR EMBEDDING

Has the advantage of embedding more specimens at a time

A

COMPOUND EMBEDDING UNIT

73
Q

MOLDS FOR EMBEDDING

Used in positioning histological tissues accurately in base molds

A

PLASTIC EMBEDDING RING AND BASE MOLD

74
Q

MOLDS FOR EMBEDDING

Compatible with most commonly used processing and storage systems

A

PLASTIC EMBEDDING RING AND BASE MOLD

75
Q

MOLDS FOR EMBEDDING

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

A

PLASTIC EMBEDDING RING AND BASE MOLD

76
Q

MOLDS FOR EMBEDDING

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

A

POP-OUT EMBEDDING MOLD

77
Q

MOLDS FOR EMBEDDING

For single tissue block outcomes/outputs only

A

POP-OUT EMBEDDING MOLD

78
Q

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

A

DISPOSABLE EMBEDDING MOLD: Peel-a-way

79
Q

MOLDS FOR EMBEDDING

Cheap to make and allow blocks to be stored without being removed

A

PAPER BOAT

80
Q

MOLDS FOR EMBEDDING

They can be placed directly in the chuck of the microtome

A

DISPOSABLE EMBEDDING MOLD: Peel-a-way

81
Q

MOLDS FOR EMBEDDING

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

A

PLASTIC ICE TRAY

82
Q

MOLDS FOR EMBEDDING

Made from thick paper or cardboard paper

A

PAPER BOAT

83
Q

MOLDS FOR EMBEDDING

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

A

PAPER BOAT

84
Q

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

A

PLASTIC ICE TRAY

85
Q

MOLDS FOR EMBEDDING

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

86
Q

MOLDS FOR EMBEDDING

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

A

WATCH GLASSES

87
Q

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

A

TEST TUBES

88
Q

MOLDS FOR EMBEDDING

Used for embedding tissue intended for EM microscopy

A

METHACRYLATE PLASTIC RESIN (EPON RESIN)

89
Q

MOLDS FOR EMBEDDING

Disadvantage: often necessary to break the tube to remove the block

A

TEST TUBES

90
Q

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

91
Q

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

92
Q

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

93
Q

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

A

F; Cellosolve is a dehydrating agent

94
Q

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

95
Q

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

[MT 6321] Histopathology Laboratory (7 decks)

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