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HISTOPATHOLOGY > MIDTERM LEC: FIXATION > Flashcards

MIDTERM LEC: FIXATION Flashcards

1
Q

First and most critical step in tissue processing because if fixation is inadequate, the succeeding tissue processing steps will also
be inadequate

A

FIXATION

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2
Q

Primary purpose:
 Preserve morphological & chemical integrity of cell in a lifelike manner as possible by stopping all cellular activities

A

FIXATION

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3
Q

Performed as soon as tissue is removed from the body

A

FIXATION

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4
Q

If tissues/cells are exposed to:
a. Air

A

drying of tissue

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5
Q

If tissues/cells are exposed to:
b. Water

A

swelling of cells

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6
Q

If tissues/cells are exposed to:
c. Saline

A

shrinkage of cell

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7
Q

Effects of Fixatives:

A

■ Hardens soft tissues in preparation for further tissue processing
■ Render cells resistant to damage caused by chemicals used in further processing
■ Inhibit decomposition caused by bacteria and fungi
■ Minimize the risk of occupational infection
■ Act as mordant for certain stains, thus promoting or hastening staining, or inhibit certain dyes

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8
Q

Characteristics of Ideal Fixative:

A
  1. Cheap
  2. Stable
  3. Safe to handle
  4. Kill cells quickly to minimize cell distortion
  5. Inhibit bacterial decomposition and autolysis
  6. Permit rapid and even penetration of tissues
  7. Must harden tissues thus easier cutting of tissues
  8. Must make cellular components insoluble to hypotonic solutions, and insensitive to subsequent processing
  9. Permit application of staining procedures
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9
Q

Fixative will forms cross-links between
soluble molecules, thus gluing them
together into an insoluble meshwork

Mechanism of Fixation

A

Additive Fixation

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10
Q

Fixative will not chemically bind with tissue
but removes water from tissue protein
groups thus causing denaturation of cell
proteins

Mechanism of Fixation

A

Non-additive Fixation

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11
Q

FACTORS AFFECTING FIXATION:

A
  1. Fixative of Choice
  2. Time
  3. Tissue-to-fixative ratio
  4. Penetration time
  5. Thickness of section
  6. Tissue components
  7. Hydrogen ion concentartion (ph)
  8. Temperature
  9. Osmolality
  10. Agitation, Vacuum
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12
Q

Fixative of Choice

Factors Affecting Fixation

A

10% Neutral Buffered Formalin (NBF)

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13
Q

Morphologic criteria for diagnosis have been established based on______

A

FormalinFixed Paraffin Embedded Specimen (FFPES)

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14
Q

Fixation must be done ________ after
cutting off blood supply (to shorten
warm ischemia time)

A

20-30mins

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15
Q

Prolonged fixation ->

A

shrinkage

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16
Q

Tissue-toFixative Ratio

A

1:10 or 1:20

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17
Q

common Tissue-toFixative Ratio

A

1:20

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18
Q

Tissue-toFixative Ratio Osmic acid fixatives:

A

1:5

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19
Q

Penetration Rate Formalin:

A

1 mm/hr (but slows down as
it goes deeper into the tissue)

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20
Q

 Larger->

Thickness of setion

A

Longer fixation time, more
fixative

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21
Q

Light Microscopy:

Thickness of setion

A

2cm2 x 0.4cm

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22
Q

Electron Microscopy:

Thickness of setion

A

1-2 mm2

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23
Q

Longer fixation time:

Tissue Components

A
  • Fibrous tissues
  • Presence of Mucus (wash with NSS)
  • Fat (cut into thin slices fixed longer)
  • Blood (flushed out with saline)
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24
Q

Shorter fixation time:

Tissue Components

A

Small or loosely textured tissues

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25
Q

Optimal pH:

Hydrogen Ion Concentration (pH)

A

6 to 8

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26
Q

If outside this pH, ultrastuctural
changes may occur

A

Hydrogen Ion Concentration (pH)

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27
Q

 May require the use of buffers

A

Hydrogen Ion Concentration (pH)

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28
Q

For Electron microscopy:

Hydrogen Ion Concentration (pH)

A

pH should match physiologic pH

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29
Q

Higher temp ->

A

faster fixation rate and
autolysis

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30
Q

Cold temp ->

A

enzyme inactivation

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31
Q

Optimal Temperature (routine):

A

Room temp to 45C

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32
Q

Tissue processors:

A

40 C

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33
Q

Microwave processing:

A

Up to 65C

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34
Q

Electron microscopy:

A

0-4C

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35
Q

Tuberculosis:

A

100C

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36
Q

Rapid biopsy:

A

60C

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37
Q

Hypertonicity ->

Osmolality

A

cell shrinkage

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38
Q

Isotonicity and hypotonicity ->

Osmolality

A

cell swelling

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39
Q

Thus, maintain tissues at slightly
hypertonic solution (400-450 mOsm)

A

Osmolality

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40
Q

Hastens fixation

A

Agitation, Vacuum

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41
Q

TYPES OF FIXATIVES
According to Composition:

A
  • simple
  • compound
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42
Q

According to Composition:
made of one component

TYPES OF FIXATIVES

A

SIMPLE

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43
Q

According to Composition
SIMPLE:

TYPES OF FIXATIVES

A

i. Aldehyde
a. Formaldehyde
b. Glutaraldehyde
ii. Metallic Fixatives
a. Mercuric chloride
b. Chromate
c. Lead
iii. Picric acid
iv. Glacial acetic acid
v. Alcohol
vi. Osmium Tetroxide
vii. Trichloroacetic acid
viii. Acetone
ix. Heat

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44
Q

According to Composition:
2 or more components or fixatives

TYPES OF FIXATIVES

A

COMPOUND

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45
Q

According to Action:

TYPES OF FIXATIVES

A
  • Microanatomical
  • Cytological
  • Histochemical
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46
Q

permits general study of tissues without altering the structure of the subjects of interest

A

Microanatomical

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47
Q

Microanatomical:

A

(10,10,HFZZBB)
1. 10% NBF
2. 10% Formol-Saline
3. Heidenhain’s Susa
4. Formol-Sublimate/Corrosive
5. Zenker’s
6. Zenker-formol (Helly’s)
7. Bouin’s
8. Brasil’s

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48
Q

preserve specific parts of the cell

A

Cytological

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49
Q

Cytological 2 TYPES:

A
  1. Nuclear Fixatives
  2. Cytoplasmic Fixatives
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50
Q

o Preserve nucleus

A

Nuclear Fixatives

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51
Q

o pH ≤ 4-6

A

Nuclear Fixatives

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52
Q

o Glacial acetic acid has affinity to nuclear chromatin

A

Nuclear Fixatives

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53
Q

Nuclear Fixatives:

A

(FCBNH)
a. Flemming’s with glacial acetic acid
b. Carnoy’s
c. Bouin’s
d. Newcomer’s
e. Heidenhain’s

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54
Q

o Other organelles aside
from nucleus

A

Cytoplasmic Fixatives

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55
Q

o pH > 4-6

A

Cytoplasmic Fixatives

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56
Q

o HAc destroys
mitochondria and Golgi
bodies

A

Cytoplasmic Fixatives

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57
Q

Cytoplasmic Fixatives:

A

(HORFF)
a. Helly’s
b. Orth’s
c. Regaud’s/Moller’s
d. Formalin with Post-chroming
e. Flemming’s without glacial acetic acid

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58
Q

Preserves chemical constituents of cells & tissues

A

Histochemical

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59
Q

Histochemical:

A

(10FANA)
1. 10% Formol Saline
2. Absolute ethanol
3. Newcomer’s
4. Acetone

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60
Q

RANGE TISSUE-TO-FIXATIVE RATIO:

A

1:15-1:20

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61
Q

RECOMMENDED TISSUE-TO-FIXATIVE RATIO:

A

1:10

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62
Q

For routine HP techniques

I. ALDEHYDES

A

Formaldehyde AKA Formalin

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63
Q

Produced from oxidation of methanol

I. ALDEHYDES

A

Formaldehyde AKA Formalin

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64
Q

Usually buffered to pH 7 with phosphate buffer

I. ALDEHYDES

A

Formaldehyde AKA Formalin

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65
Q

Formaldehyde AKA Formalin
Concentrations:
100%

I. ALDEHYDES

A

GAS FORM

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66
Q

Formaldehyde AKA Formalin
Concentrations:
37-40%

I. ALDEHYDES

A

stock concentration (causes overhardening
of the external surfaces of tissues)

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67
Q

Formaldehyde AKA Formalin
Concentrations:
10%

I. ALDEHYDES

A

working solution; most commonly used

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68
Q

Formaldehyde AKA Formalin ADVANTAGES:

I. ALDEHYDES

A

cheap, readily available, easy to prepare, stable, compatible with most stains

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69
Q

Formaldehyde AKA Formalin DISADVANTAGES:

I. ALDEHYDES

A

nose and eye-irritant, may cause allergic dermatitis

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70
Q

Formalin diluted with 10% NaCl

I. ALDEHYDES

A

10% Formol-Saline

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71
Q

Traditionally, the most common fixative

I. ALDEHYDES

A

10% Formol-Saline

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72
Q

Recommended for CNS tissue and general post-mortem tissues for histochemical examination

I. ALDEHYDES

A

10% Formol-Saline

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73
Q

```

10% Formol-Saline ADVANTAGES:

I. ALDEHYDES

A

ideal for Silver impregnation staining technique

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74
Q

10% Formol-Saline DISADVANTAGES:

I. ALDEHYDES

A

tissue shrinks during alcohol dehydration [Remedy: Secondary fixation]

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75
Q

 pH 7

I. ALDEHYDES

A

10% Neutral Buffered Formalin (NBF) or Phosphate Buffered Formalin

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76
Q

```

Best general tissue fixative

I. ALDEHYDES

A

10% Neutral Buffered Formalin (NBF) or Phosphate Buffered Formalin

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77
Q

Best for iron-containing pigments and elastic fibers which do not stain well after Susa, Zenker or Chromate fixation,

I. ALDEHYDES

A

10% Neutral Buffered Formalin (NBF) or Phosphate Buffered Formalin

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78
Q

```

10% Neutral Buffered Formalin (NBF) or Phosphate Buffered Formalin DISADVANTAGES:

I. ALDEHYDES

A

longer to prepare, inert to phospholipids and neutral
fats

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79
Q

Has HgCl2

I. ALDEHYDES

A

Formol-Sublimate/Corrosive

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80
Q

Formol-Sublimate/Corrosive ADV:

I. ALDEHYDES

A

Excellent for silver reticulum staining method, does not need washing, fixes lipids

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81
Q

Formol-Sublimate/Corrosive DISADVANTAGES:

I. ALDEHYDES

A

forms mercuric chloride deposits

82
Q

Has 95% ETOH, Picric acid, and GHAc

I. ALDEHYDES

A

Gendre’s (Alcoholic Formalin)

83
Q

```

Gendre’s (Alcoholic Formalin) ADV:

I. ALDEHYDES

A

good for microincineration techniques, fixes sputum

84
Q

For gastrointestinal (GI) tissues, prostate biopsies, and bone marrow (BM)

I. ALDEHYDES

A

Hollande’s

85
Q

Made up of 2 formaldehyde resides linked by three carbon
chains

I. ALDEHYDES

A

Glutaraldehyde

86
Q

```

For enzyme histochemistry and electron microscopy

I. ALDEHYDES

A

Glutaraldehyde

87
Q

Glutaraldehyde ADVANTAGES:

I. ALDEHYDES

A

more pleasant and less irritating compared to formalin

88
Q

Glutaraldehyde DISADVANTAGES:

I. ALDEHYDES

A

Less stable and more expensive than formalin

89
Q

 Container must be refrigerated

I. ALDEHYDES

A

Glutaraldehyde

90
Q

Glutaraldehyde
Concentrations:
for immunoEM

I. ALDEHYDES

A

0.25%

91
Q

Glutaraldehyde
Concentrations:
for small TSE fragments

I. ALDEHYDES

A

2.5%

92
Q

Glutaraldehyde
Concentrations:
most common

I. ALDEHYDES

A

3%

93
Q

Glutaraldehyde
Concentrations:
for large TSE

I. ALDEHYDES

A

4%

94
Q

Polymer of formalin

I. ALDEHYDES

A

Paraformaldehyde

95
Q

Powder in form, used in 4%

I. ALDEHYDES

A

Paraformaldehyde

96
Q

Plastic embedding

I. ALDEHYDES

A

Paraformaldehyde

97
Q

For ultrathin and electron microscopy

I. ALDEHYDES

A

Paraformaldehyde

98
Q

Acrolein in glutaraldehyde or formalin

I. ALDEHYDES

A

Karnovsky’s Paraformaldehyde/Glutaraldehyde

99
Q

P: for Electron Histochemistry and Electron Immunocytochemistry

I. ALDEHYDES

A

Karnovsky’s Paraformaldehyde/Glutaraldehyde

100
Q

ADV: no smudging of nuclei and distortion of staining compared with formalin

I. ALDEHYDES

A

40% Aqueous Glyoxal

101
Q

 D: reduced staining capacity
[Remedy: increase staining time]

A

40% Aqueous Glyoxal

102
Q

METALLIC FIXATIVES:

A
  1. Mercuric chloride
  2. Chromates
  3. Lead
103
Q

Mercuric chloride:

II. METALLIC FIXATIVES

A

(ZZCHBS)
Zenker
Zenker-Formol (Helly’s)
Carnoy-Lebron
Heidenhain’s Susa
B5
Schaudinn’s

104
Q

Chromates:

II. METALLIC FIXATIVES

A

(CROP)
Chromic acid
Regaud’s/Muller’s
Orth’s
Potassium dichromate

105
Q

Most common metallic fixative

II. METALLIC FIXATIVES

A

Mercuric Chloride (HgCl2)

106
Q

A: penetrates and hardens tissue rapidly

II. METALLIC FIXATIVES

A

Mercuric Chloride (HgCl2)

107
Q

Routine fixative of choice for preservation of cell detail in tissue photography

II. METALLIC FIXATIVES

A

Mercuric Chloride (HgCl2)

108
Q

 Conc. 5-7%

II. METALLIC FIXATIVES

A

Mercuric Chloride (HgCl2)

109
Q

Mostly incorporated in compound fixatives

II. METALLIC FIXATIVES

A

Mercuric Chloride (HgCl2)

110
Q

 DADV: Banned worldwide d/t extreme toxicity, marked cell shrinkage [Remedy: add acid]

II. METALLIC FIXATIVES

A

Mercuric Chloride (HgCl2)

111
Q

May produce black granular deposits except in Heidenhain’s Susa

II. METALLIC FIXATIVES

A

Mercuric Chloride (HgCl2)

112
Q

May produce black granular deposits except in Heidenhain’s Susa
Mercuric Chloride (HgCl2) Remedy:

II. METALLIC FIXATIVES

A

Dezenkerization
0.5% Iodine + 70% ETOH  H20  5% Na thiosulfate  H20

113
Q

HgCl2 + potassium dichromate + glacial acetic acid

II. METALLIC FIXATIVES

Mercuric Chloride (HgCl2)

A

Zenker’s

114
Q

Good general fixative for adequate preservation of all kinds of tissues

II. METALLIC FIXATIVES

Mercuric Chloride (HgCl2)

A

Zenker’s

115
Q

Good for Trichrome staining

II. METALLIC FIXATIVES

Mercuric Chloride (HgCl2)

A

Zenker’s

116
Q

HgCl2 + potassium dichromate + strong formalin (40%)

II. METALLIC FIXATIVES

Mercuric Chloride (HgCl2)

A

Zenker-formol/Helly’s

117
Q

For piituitary gland, BM, blood-containing organs, preserves cytoplasmic granules

II. METALLIC FIXATIVES

Mercuric Chloride (HgCl2)

A

Zenker-formol/Helly’s

118
Q

Brown pigments are removed with saturated alcoholic picric acid or NaOH

II. METALLIC FIXATIVES

Mercuric Chloride (HgCl2)

A

Zenker-formol/Helly’s

119
Q

Susa: Su = sublimate ; Sa = saure (acid)

II. METALLIC FIXATIVES

Mercuric Chloride (HgCl2)

A

Heidenhain Susa

120
Q

HgCl2 + NaCl + TCA + glacial acetic acid + formalin

II. METALLIC FIXATIVES

Mercuric Chloride (HgCl2)

A

Heidenhain Susa

121
Q

Skin tumor biopsy

II. METALLIC FIXATIVES

Mercuric Chloride (HgCl2)

A

Heidenhain Susa

122
Q

ADV: minimum cell shrinkage and tissue hardening due to counter-balance effect of acids and mercury:
Acids : swelling
Mercury: shrinkage

II. METALLIC FIXATIVES

Mercuric Chloride (HgCl2)

A

Heidenhain Susa

123
Q

Does not produce black pigments

II. METALLIC FIXATIVES

Mercuric Chloride (HgCl2)

A

Heidenhain Susa

124
Q

DADV: Weigert’s staining of elastic fibers not possible

II. METALLIC FIXATIVES

Mercuric Chloride (HgCl2)

A

Heidenhain Susa

125
Q

```

HgCl2 + Anhydrous Na acetate

II. METALLIC FIXATIVES

Mercuric Chloride (HgCl2)

A

B5 Fixative

126
Q

BM biopsies

II. METALLIC FIXATIVES

Mercuric Chloride (HgCl2)

A

B5 Fixative

127
Q

Conc.: 1-2% aqueous solutions

II. METALLIC FIXATIVES

Chromate Fixatives

A

Chromic acid

128
Q

Precipitates all proteins, and preserves carbohydrates

II. METALLIC FIXATIVES

Chromate Fixatives

A

Chromic acid

129
Q

P: chromatin, mitochondria, mitotic figures, golgi bodies, RBC and colloid-containing TSEs

II. METALLIC FIXATIVES

Chromate Fixatives

A

Regaud’s/Muller’s

130
Q

DADV: prolonged fixation may lead to blackening of tissue pigment
[Remedy: Wash in running tap water before
dehydration]

II. METALLIC FIXATIVES

Chromate Fixatives

A

Regaud’s/Muller’s

131
Q

P: early degenerative processes and necrosis,
demonstration of Rickettsia and other bacteria

II. METALLIC FIXATIVES

Chromate Fixatives

A

Orth’s

132
Q

E: preserves myelin

II. METALLIC FIXATIVES

Chromate Fixatives

A

Orth’s

133
Q

E: preserves lipids, mitochondria, at pH4.5-5.2,
cytoplasm, chromatin and chromosome are fixed

II. METALLIC FIXATIVES

Chromate Fixatives

A

3% Potassium dichromate

134
Q

Corrosive, thus avoid skin contact

II. METALLIC FIXATIVES

Chromate Fixatives

A

3% Potassium dichromate

135
Q

P: for acid mucopolysaccharides and mucin

II. METALLIC FIXATIVES

Chromate Fixatives

A

4% Aqueous Lead

136
Q

DADV: Prolonged standing  formation of insoluble lead carbonate
[Remedy: add drops of acetic acid to dissolve residue]

II. METALLIC FIXATIVES

A

4% Aqueous Lead

137
Q

Used in strong saturated aqueous solution (1%)

A

PICRIC ACID

138
Q

For Glycogen preservation

A

PICRIC ACID

139
Q

ADV: may be used as a stain as yellowing of tissue will prevent small fragments from being overlooked; suitable also with Aniline stains

A

PICRIC ACID

140
Q

PICRIC ACID DISADVANTAGES:

A
  1. Explosive when dry
    [Remedy: add distilled H2O or 0.5-1% saturated alcohol]
  2. Yellowing of tissues  excessive staining
    [Remedy: immerse in Li2CO3 with 70%ROH  water 
    70% ethanol  5% Na thiosulfate  water]
  3. RBC hemolysis
     (PBB)
141
Q

PICRIC ACID:

A

(PBB)
1. Bouin’s
2. Brasil’s

142
Q

P: for embryo and pituitary biopsies, and tissues to be stained with Masson’s Trichrome

III. PICRIC ACID

A

Bouin’s

143
Q

ADV: minimum cell shrinkage and tissue hardening due to counter-balance effect of glacial acetic acid (swelling) and picric acid (shrinking)

III. PICRIC ACID

A

Bouin’s

144
Q

DADV: poorly penetrates large tissue, thus limited to small fragments of tissues

III. PICRIC ACID

A

Bouin’s

145
Q

C: TCA

III. PICRIC ACID

A

Brasil’s

146
Q

ADV: Better and less messy than Bouin’s

III. PICRIC ACID

A

Brasil’s

147
Q

Incorporated in compound fixatives

A

GLACIAL ACETIC ACID

148
Q

Solidifies at 17CI

A

GLACIAL ACETIC ACID

149
Q

Important for nuclear fixatives (precipitates nucleoproteins, chromatins)

A

GLACIAL ACETIC ACID

150
Q

Destroys mitochondria and Golgi elements, thus not for cytoplasmic fixation

A

GLACIAL ACETIC ACID

151
Q

ADV: good for glycogen

A

ALCOHOL FIXATIVES

152
Q

DADV: never for FATs and LIPOPROTEINS (dissolves); causes polarization of glycogen (granules will move towards the poles
or ends of the cells)

A

ALCOHOL FIXATIVES

153
Q

Effect: rapidly denatures and precips CHONs, preserves nuclear
stains

A

ALCOHOL FIXATIVES

154
Q

ALCOHOL FIXATIVES:

A

(CEMING)
1. Carnoy’s Fixative
2. 70-100% Ethanol
3. 100% Methanol/Wood alcohol
4. 95% Isopropyl Alcohol/Rubbing Alcohol
5. Newcomer’s
6. Gendre’s (Alcoholic Formalin)

155
Q

Most rapid tissue fixative

A

Carnoy’s Fixative

156
Q

Fixing brain tissues for rabies diagnosis

A

Carnoy’s Fixative

157
Q

E: fixes Nissl granules (Tigroid substance) and cytoplasmic
granules

A

Carnoy’s Fixative

158
Q

1.

Enzyme studies

A

70-100% Ethanol

159
Q

Does not fix but preserves glycogen

A

70-100% Ethanol

160
Q

Dry and wet smears, BM smears, bacterial smears

A

100% Methanol/Wood alcohol

161
Q

Touch prep smears to be Wright-stained

A

95% Isopropyl Alcohol/Rubbing Alcohol

162
Q

Mucopolysaccharides and nuclear CHONs

A

Newcomer’s

163
Q

```

Better reaction in Feulgen stain than Carnoy’s

A

Newcomer’s

164
Q

Pale yellow powder in water (6% in 20C)

A

OSMIUM TETROXIDE / OSMIC ACID

165
Q

Ultrathin sections in Electron Microscopy

A

OSMIUM TETROXIDE / OSMIC ACID

166
Q

E: Fixes and stains conjugated fats and lipids blac

A

OSMIUM TETROXIDE / OSMIC ACID

167
Q

DADV: very expensive, very volatile, inhibits hematoxylin

A

OSMIUM TETROXIDE / OSMIC ACID

168
Q

OSMIUM TETROXIDE / OSMIC ACIDTissue-to-fixative ratio:

A

1:5

169
Q

OSMIUM TETROXIDE / OSMIC ACID:

A

(OFF)
1. Flemming’s
2. Flemming’s w/o acetic acid

170
Q

Most common osmic acid fixative

A

Flemming’s

171
Q

P: nuclear structures

A

Flemming’s

172
Q

Effect: permanently fixes fat

A

Flemming’s

173
Q

ADV: needs less amount of fixative

A

Flemming’s

174
Q

Cytoplasmic structures

A

Flemming’s w/o acetic acid

175
Q

Incorporated also in compound fixatives

A

TRICHLOROACETIC FIXATIVES

176
Q

Marked swelling effect on tissues

A

TRICHLOROACETIC FIXATIVES

177
Q

Poor penetrating agent thus for small pieces of tissues or bones

A

TRICHLOROACETIC FIXATIVES

178
Q

Weak decalcifying agent, thus has softening effect on dense fibrous tissues

A

TRICHLOROACETIC FIXATIVES

179
Q

1.

Used at cold temp -5-4C

A

ACETONE

180
Q

For water-diffusible enzymes (Phosphatase, Lipase)

A

ACETONE

181
Q

For brain tissues (such as in Rabies)

A

ACETONE

182
Q

DADV: Dissolves fat, evaporates rapidly

A

ACETONE

183
Q

Principle: Thermal coagulation of tissue proteins

A

HEAT

184
Q

For rapid diagnosis: frozen tissue sections and Bacterial smear
prep

A

HEAT

185
Q

PCPL: Increases movement of molecules to accelerate fixation, staining, decalcification

A

Microwave Technique

186
Q

ADV: Tissue is heated right through the block in a very short time; preserves neurochemical substances (acetylcholine)

A

Microwave Technique

186
Q

Electron Microscopy and immunohistochemistry

A

Microwave Technique

187
Q

DADV: Penetrates at 10-15mm thickness; spores and pathogen may remain in tissues

A

Microwave Technique

188
Q

SECONDARY FIXATION:

A
  • Refixation” with another fixative
  • Post-Chromatization
188
Q

Microwave Technique Optimum Temp:

A

45-55C

189
Q

Done before dehydration or restaining of deparaffinized
TSEs

A

Refixation” with another fixative

190
Q

Improve demonstration of substance

A

Refixation” with another fixative

191
Q

Make special staining techniques possible (with the next fixative as mordant)

A

Refixation” with another fixative

192
Q

Ensure further and complete handling

A

Refixation” with another fixative

193
Q

Use of 2.5-3% aqueous K2Cr2O7 that will act as mordant

A

Post-Chromatization

194
Q

Removal of excess fixative to improve staining and remove
artifacts

A

WASHING OUT

195
Q

WASHING OUT:

A
  1. Tap Water
  2. 50-70% ROH
  3. Alcoholic iodine
196
Q

for excess formalin, osmic acid, and chromates

A

Tap Water

197
Q

for excess picric acid fixatives and
Gendre’s

A

50-70% ROH

198
Q

for excess mercuric chloride

A

Alcoholic iodine

HISTOPATHOLOGY (13 decks)

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