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HCT > Lec 2: Tissue Processing 1 & 2 > Flashcards

Lec 2: Tissue Processing 1 & 2 Flashcards

1
Q

The second step in manual tissue processing

A

Dehydration

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2
Q

The process of removing intracellular and extracellular water from the tissue

A

Dehydration

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3
Q

Characteristics of an ideal dehydrating solution (7)

A
  1. Should dehydrate properly/rapidly without causing shrinkage or distortion
  2. Should dehydrate even fatty tissues
  3. Should NOT evaporate quickly
  4. Should NOT harden tissue excessively
  5. Should NOT remove stains
  6. Should NOT be toxic to the body
  7. Should NOT be a fire hazard
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4
Q

Dehydrating agent should NOT be less than ___ times the volume of the tissue.

A

10

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5
Q

Commonly used dehydrating agents (6)

A
  • alcohol
  • acetone
  • cellosolve
  • dioxane
  • triethyl phosphate
  • tetrahydrofuran
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6
Q
  • clear, colorless, flammable
  • for routine dehydration
  • not poisonous
  • fast-acting
  • penetrates tissue easily
  • mixed with water and other organic solvents.
A

Ethyl Alcohol
• best dehydrating agent

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7
Q
  • toxic dehydrating agent
  • for blood & tissue film
  • for smear preparations
A

Methyl Alcohol

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8
Q
  • slow dehydrating agent
    › doesn’t require rapid processing
  • utilized in plant and animal micro-techniques
  • less shrinkage & hardening
A

Butyl Alcohol

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9
Q

ACETONE
1. boiling point
2. Dehydrates how long?
3. Can tissues be placed in it for a prolonged period of time?
4. How well does it penetrate the tissue?

A
  1. 56°C
  2. 30 minutes to 2 hours
  3. NO, because it causes brittleness in tissues.
  4. Penetrates poorly
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10
Q
  • clear and colorless
  • rapid-acting
  • for most urgent biopsies
  • extremely volatile & flammable
  • mixes with water, ethanol, and most organic solvents
A

Acetone

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11
Q
  • rapid-acting
  • combustible (110-120°F) & toxic
  • tissue can be stored for months without hardening or distorting.
A

Cellosolve

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12
Q

CELLOSOLVE
1. boiling point
2. Other name

A
  1. 156.4°C
  2. Ethylene glycol monoethyl ether
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13
Q

The dehydrating agent wherein the reproductive, fetal, urinary, and blood systems are particularly vulnerable to its toxic side effects

A

Cellosolve

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14
Q

DIOXANE
1. boiling point
2. Refractive index
3. Other name

A
  1. 101.5°C
  2. 1.42
  3. Diethylene dioxide
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15
Q
  • readily miscible with water, melted paraffin, alcohol, and xylol
  • tissues can be left for a long time without affecting the staining properties
A

Dioxane

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16
Q
  • miscible in water & paraffin
  • can dissolve many substances including fats
  • for demixing, clearing, and dehydrating paraffin sections
  • odorous
  • evaporates rapidly
A

Tetrahydrofuran

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17
Q

TRIETHYL PHOSPHATE
1. Boiling point
2. Soluble in what substances

A
  1. 215°C
  2. Alcohol, water, ether, benzene, Chloroform, acetone, xylene
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18
Q
  • used to dehydrate sections and smears
  • minimum shrinkage
  • removed water readily
  • little distortion and hardening
A

Triethylphosphate

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19
Q

The killing, penetration, and hardening of tissues

A

Fixation

  • killing: stops metabolic processes
  • penetration: fixative penetrates tissue
  • hardening: for easier trimming & cutting
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20
Q

First and most critical step involving preserving fresh tissue

A

Fixation

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21
Q

The alteration of tissues by stabilizing proteins so that the tissues become resistant to further changes

A

Fixation

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22
Q

Primary Aim of Fixation

A

To preserve the morphologic and chemical integrity of the cell

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23
Q

Secondary Aim of Fixation

A

To harden and protect the tissue from trauma

24
Q

The functions of fixation

A
  • to preserve the tissue
  • to prevent breakdown of cellular elements
  • to coagulate/precipitate protoplasmic substances
25
Q

The practical considerations to optimize fixation of tissue (8)

A
  • duration of fixation
  • osmolality
  • concentration
  • penetration
  • volume
  • speed
  • temperature
  • thickness
26
Q

Practical Considerations:

  1. Specimen should be fixed ___ hour/s from removal.
  2. Fixative must be ___ times the size of the tissue
  3. Ratio of fixative to tissue.
  4. Formalin diffuses into tissue approximately __mm/hr.
  5. Duration of fixation for LM & EM.
A
  1. Specimen should be fixed at least 1 hour/s from removal.
  2. Fixative must be 20 times the size of the tissue
  3. 20:1 or 10:1
  4. Formalin diffuses into tissue approximately 1mm/hr.
  5. Duration of fixation
    a. LM: 2/4–6 hours
    b. EM: 3 hours
27
Q

Practical Considerations:

  1. Osmolality
    a. LM:
    b. EM:
    c. 10% NBF:
  2. Concentration
    a. Formaldehyde:
    b. Glutaraldehyde:
  3. Temperature
    a. Routine manual:
    b. Routine automated:
    c. EM:
    d. DNA:
    e. RNA:
    f. microwave:
  4. Thickness of tissue
    a. LM:
    b. EM:
A
  1. Osmolality
    a. LM: slightly hypertonic (400-450 mOsm)
    b. EM: isotonic (340 mOsm)
    c. 10% NBF: 1500 mOsm
  2. Concentration
    a. Formaldehyde: 10%
    b. Glutaraldehyde: 3%; 0.25%
  3. Temperature
    a. Routine manual: 20-22°C
    b. Routine automated: 40°C
    c. EM: 0-40°C
    d. DNA: 65°C
    e. RNA: 45°C
    f. microwave: 65°C
  4. Thickness of tissue
    a. LM: 2cm
    b. EM: 1-2mm
28
Q

Characteristics of a Good Fixative (8)

A
  • cheap & economical
  • stable and safe to handle
  • fast-acting & even penetration
  • inhibits bacterial decomposition & autolysis
  • at least isotonic
  • hardens tissue
  • renders tissue insensitive to subsequent processing
  • is compatible with many staining procedures
29
Q
  1. What is a simple fixative?
  2. Give examples.
A
  1. Made up of only 1 component substance
  2. Examples:
    a. Aldehyde
    b. Metallic fixative
    c. Picric Acid
    d. Acetic acid
    e. Acetone
    f. Alcohol
    g. Osmium tetroxide
30
Q
  1. What is a Compound fixative?
  2. Give examples
A
  1. Made up of 2 or more fixatives added together
  2. Examples:
    a. Zenker’s Fluid
    b. Bouin’s fluid
    c. Formol saline
31
Q

Fixatives under Aldehyde Fixative

A
  • formaldehyde (formalin)
  • 10% formol saline
  • 10% NBF
  • Formol-corrosive
  • alcoholic formalin
  • glutaraldehyde
  • formol calcium
  • Karnovsky’s Paraformaldehyde Glutaraldehyde
  • Acrolein
32
Q
  • buffered at pH 7 to 8
  • fixed tissue by forming a cross linkage
A

Formaldehyde (formalin)

33
Q
  • for fixation of CNS tissues and general post mortem tissue
  • made up of 40% formaldehyde + NaCl + distilled water
  • fixation time: 12 to 24 hours
A

10% formol saline

34
Q

10% Formol Saline
1. Fixation time
2. Composition

A
  1. 12 to 24 hours
  2. 40% formaldehyde + NaCl+ distilled water
35
Q
  • for preservation & storage of surgical, post mortem, and research specimens
  • best for tissues containing iron pigments & elastic fibers
A

10% NBF

36
Q

10% NBF
Fixation time

A

4 to 24 hours

37
Q
  • corrosive
  • for routine post-mortem tissues
  • fixation time: 3 to 24 hours
A

Formol-corrosive

38
Q

Formol-corrosive
Fixation time

A

3 to 24 hours

39
Q
  • denaturing fixative with the additive in the cross links effect of formalin
  • for rapid diagnosis
  • for preservation of glycogen & micro-incineration
  • used to fix sputum and coagulate mucus
A

Alcoholic Formalin

40
Q

Alcoholic Formalin
1. Post fixation for ___ hours enhances the immunoperoxidase studies on tissues.
2. Other name.

A
  1. 6 hours or more
  2. Gendre’s Fixative
41
Q

Glutaraldehyde
1. Composition
2. Fixation time

A
  1. 2 formaldehyde linked by 3 carbon chains
  2. 1½ hour to 2 hours
42
Q
  • for adipose tissue (phospholipid)
A

Formol Calcium

43
Q
  • surgical biopsy
A

Acrolein

44
Q

Examples of the fixatives in Mercuric chloride under Metallic Fixative

A
  • Zenker’s Fluid
  • Zenker-formol (Helly’s solution)
  • Hedenhain’s Susa
  • B-5 Fixative
45
Q
  • for tissue photography: renal tissues, fibrin, CT and muscles
  • ADVANTAGE:
    » best for hematopoietic & reticuloendothelial tissues
  • DISADVANTAGE:
    » rapidly hardens outer layer of tissue
A

Mercuric Chloride
• most common metallic fixative

46
Q
  • used to prevent turbidity and formation of dark precipitate
A

Zenker’s Fluid

47
Q

Zenker’s Fluid
1. Composition
2. Fixation time

A
  1. Mercuric chloride + Glacial acetic acid
  2. 12 to 24 hours
48
Q
  • excellent for bone marrow, extra medullary hematopoiesis, and intercalated disc of the cardiac muscle.
A

Zenker-formol (Helly’s)

49
Q

Zenker-formol
1. Fixation time
2. Other name

A
  1. 4 to 24 hours
  2. Helly’s solution
50
Q

Hedenhain’s Susa
1. Recommended for ___?
2. Fixation time

A
  1. For tumor biopsy especially the skin
  2. 3 to 12 hours
51
Q
  • for bone marrow biopsy
  • enhances nuclear detail to identify normal & abnormal cell types
A

B-5 Fixative

52
Q

B-5 Fixative
1. Fixation time

A
  1. 4 to 8 hours
53
Q

Chromate acid preserves ___

A

Carbohydrates

54
Q
  • For the demonstration of:
    » chromatin
    » mitochondria
    » Golgi bodies
    » RBC
A

Regaud’s Fluid

55
Q

Regaud’s Fluid
1. Tissue should NOT be thicker than ____
2. Fixation time
3. Other name

A
  1. 2-3 mm
  2. 12 to 48 hours
  3. Muller’s solution
56
Q

Potassium Dichromate
1. Preserves ___
2. pH range

A
  1. Preserves lipids and mitochondria
  2. to preserve mitochondria, pH should be 4.5 to 5.2
57
Q
  • recommended for the study of early degenerative processes and tissue necrosis
  • for demonstration of rickettsia bacteria and preserves better myelin
  • Fixation time: 36 to 72 hours
A

Orth’s fluid

HCT (9 decks)

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