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HISTOPATH LEC > FIXATION 2012 GREGORIOS > Flashcards

FIXATION 2012 GREGORIOS Flashcards

1
Q

It is the art and science performed by the histotechnologist to produce a tissue section of good quality

A

Histotechnology

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2
Q

What is the first and most critical step in histotechnology

A

fixation

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3
Q

What the primary aim of fixation?

A

to preserve the morphologic and chemical integrity of the cell in as life-like manner as possible

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4
Q

what is the cell composed of?

A
  • proteins
  • lipids
  • carbohydrates
  • organic
  • inorganic
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5
Q

these are loosely held together in the cellular protoplasm by hydrogen bonds or salt linkages that are in constant state of chemical and biological equilibrium

A

cellular substances

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6
Q

in fixation, what are being preserved?

A
  • shape
  • structure
  • intercellular relationships
  • chemical constituents
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7
Q

Fixation prevents the what of tissues after removal from the body?

A
  • degeneration
  • putrefaction
  • decomposition
  • distortion
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8
Q

What happens to all vital cellular processes when the tissue is placed in a fixative?

A

they stop

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9
Q

The weak chemical associations are changed into what that will not break down with further histologic handling

A

changed into stable complexes

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10
Q

What is the secondary goal of fixation?

A

to harden and protein the tissue from the trauma of further handling, so that it is easier to cut during gross examination

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11
Q

How does fixation preserve the tissue?

A

by stopping all cellular activities

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12
Q

leaving the tissue in water, a hypertonic solution, will cause the cell to swell

True or false

A

false

hypotonic

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13
Q

leaving the tissue in water, a hypertonic solution, will cause the cell to swell

True or false

A

false

hypotonic

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14
Q

What happens to the cell if the tissue is left in water (hypotonic solution)?

A

the cell will swel

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15
Q

What happens to the cell if the tissue is left in water (hypotonic solution)?

A

the cell will swell

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16
Q

a strong salt (hypertonic solution) will the cell to swell

True or false

A

false

cell will shrink

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17
Q

a strong salt (hypertonic solution) will the cell to swell

True or false

A

false

cell will shrink

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18
Q

The surigcal removal of the tissue from the body will lead to what to the tissue?

A

leading to a degradative chemical process or cell death

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19
Q

cell death is caused by the deprivation of what?

A

deprivation of oxygen and nutrition

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20
Q

Every cell in the body has a structure or “suicide sac” within its cytoplasm called what?

A

lysosome

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21
Q

this contains hydrolytic enzymes that are released when the integrity of the cell is destroyed

A

lysosome

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22
Q

postmortem decomposition is called …

A

autolysis

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23
Q

this occurs due to the action of these hydrolytic enzymes

A

autolysis

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24
Q

Fixation prevents autolysis

true or false

A

true

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25
Q

How does fixation prevent autolysis?

A

by inactivating the lysosomal enzymes, or by chemically altering, stabilizing, and making the tissue components insoluble

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26
Q

Decomposition is also called …

A

putrefaction

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27
Q

Decomposition is also called …

A

putrefaction

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27
Q

Decomposition is also called …

A

putrefaction

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27
Q

Decomposition is also called …

A

putrefaction

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28
Q

Decomposition is also called …

A

putrefaction

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29
Q

Fixation also protects the tissue from further putrefaction after death due to what?

A

due to bacterial or fungal colonization and overgrowth

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30
Q

Fixation also protects the tissue from further putrefaction after death due to what?

A

due to bacterial or fungal colonization and overgrowth

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31
Q

What are the two basic mechanisms involved in fixation?

A
  1. additive fixation
  2. non additive fixation
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32
Q

This is the mechanism involved in fixation whereby the chemical constituent of the fixative is taken in and BECOMES PART of the tissue by forming cross-links or molecular complexes and giving stability to the protein

A

ADDITIVE FIXATION

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33
Q

This is the mechanism involved in fixation whereby the chemical constituent of the fixative is taken in and BECOMES PART of the tissue by forming what?

A

by forming cross-links or molecular complexes

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34
Q

What are examples of additive fixation?

A
  • formalin
  • mercury
  • osmium tetroxide
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35
Q

This is a mechanism involved in fixation whereby the fixing agent is NOT INCORPORATED into the tissue, but ALTERS the tissue composition and stabilizes the tissue by removing the bound water attached to H-bonds of certain groups within the protein molecule

A

NON ADDITIVE FIXATION

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36
Q

What is an example of a non additive fixation?

A

alcoholic fixatives

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37
Q

What are the 6 MAIN FACTORS INVOLVED IN FIXATION

CTTHOD

A
  1. Concentration
  2. Temperature
  3. Thickness of section
  4. Hydrogen Ion concentration
  5. Osmolality
  6. Duration of Fixation
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38
Q

Satisfactory fixation occurs between what pH levels?

A

pH 6 and pH 8

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39
Q

Fixation of surgical specimens is traditionally carried out at what temperature?

A

at room temperature

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40
Q

Many laboratories use tissue processors that work at what temperature?

A

40C

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41
Q

For electron microscopy and some histochemistry the ideal temperature is what?

A

0-4C

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42
Q

What kind of cells are best fixed at room temperature even for electron microscopy?

A

mast cells

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43
Q

nucleic acids do not react with fixatives to any extent at 4C

True or false

A

FALSE

at room temperature

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43
Q

nucleic acids do not react with fixatives to any extent at 4C

True or false

A

FALSE

at room temperature

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44
Q

Nucleic acids do not react with chemical reactions including those involved in fixation are more rapid at higher temperatures

true or false

A

true

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45
Q

Formalin is heated at what temperature is sometimes used for rapid fixation of VERY URGENT biopsy specimens, although the risk of tissue distortionis increased?

A

60C

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46
Q

Formalin at what temperature can be used to fix tissues with tuberculosis?

A

100C

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47
Q

What must be the thickness of the section for electron microscopy?

A

1 to 2 mm^2

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48
Q

what is the thickness of the section in light microscopy?

A

2 cm^2

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49
Q

if the tissue must be thin, the measurement must be how thin for light microscopy?

A

0.4 cm

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50
Q

Large solid tissue, such as UTERUS, should not be opened or sliced thinly

True or false

A

false

should be opened or sliced thinly

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51
Q

Large solid tissue, such as UTERUS, should not be opened or sliced thinly

True or false

A

false

should be opened or sliced thinly

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52
Q

Brain is usually suspended in parts

True or False

A

FALSE

suspended whole

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53
Q

Brain is usually suspended in parts

True or False

A

FALSE

suspended whole

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54
Q

Brain is usually suspended whole in what fixative?

A

10% buffered formalin

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55
Q

Brain is usually suspended whole in 10% buffered formalin for how long?

A

2-3 weeks

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56
Q

What kind of solution gives rise to cell shrinkage?

A

Hypertonic solution

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57
Q

these fixatives causes cell swelling and poor fixation

A

Isotonic as well as hypotonic fixatives

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58
Q

Regarding osmolality, best results are usually obtained using what solution?

A

SLIGHTLY HYPERTONIC SOLUTIONS

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59
Q

Regarding osmolality, best results are usually obtained using what solution?

A

SLIGHTLY HYPERTONIC SOLUTIONS

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60
Q

How many mOsm is a slightly hypertonic solution?

A

400 - 450 mOsm

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61
Q

Isotonic solutions are 340 mOsm

True or false

A

TRUE

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62
Q

What is commonly added to osmium tetroxide fixatives for electron microscopy?

A

Sucrose

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63
Q

Sucrose is commonly added to what fixative for electron microscopy?

A

osmium tetroxide

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64
Q

Sucrose is commonly added to osmium tetroxide fixative for what?

A

electron microscopy

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65
Q

The vehicle osmolality is generally more important than the total osmolality fixative, and ideally should be more or less hypertonic with tissues in their normal living environment

True or false

A

TRUE

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66
Q

For glutaraldehyde fixatives, the vehicle osmolality should be more or less 300 mOsm

True or false

A

true

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67
Q

This is normally used as a 10% solution

A

Formaldehyde

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68
Q

Glutaraldehyde is normally used as a 3% solution

True or false

A

true

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69
Q

The presence of a what causes polymerization of the aldehyde, with consequent decrease in its effective concentration

A

The presence of a buffer

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70
Q

The presence of a buffer causes what?

A

Polymerization of the aldehyde

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71
Q

High concentrations of glutaraldehyde have been found to be an ideal concentration for immunoelectron microscopy

True or false

A

FALSE

Low concentrations

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72
Q

High concentrations of glutaraldehyde have been found to be an ideal concentration for immunoelectron microscopy

True or false

A

FALSE

Low concentrations

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73
Q

What is the ideal concentration of glutaraldehyde in immunoelectron microscopy?

A

low concentrations of glutaraldehyde (0.25%)

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74
Q

Primary fixation in buffered formalin is usually carried out for how long?

A

2-6 hours during the day the specimen is obtained

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75
Q

A specimen in primary fixation in buffered formalin may remain in fixative over the weekend without much adverse effect

True or false

A

true

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76
Q

Most of the formalin can be washed out after fixation in how many hours?

A

24 hours

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77
Q

Prolonged fixation may cause what?

A
  • shrinkage
  • hardening of tissue
  • may severely inhibit enzyme activity and immunological reactions
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78
Q

Prolonged fixation may cause what?

A
  • shrinkage
  • hardening of tissue
  • may severely inhibit enzyme activity and immunological reactions
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79
Q

Washing of the tissue in running water considerably restores the activity of some enzymes

true or false

A

true

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80
Q

For electron microscopy, it is recommended that diced tissues be fixed for how many hours?

A

3 hours

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81
Q

For electron microscopy, after fixing the diced tissues for 3 hours, where should it be placed?

A

in a holding buffer

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82
Q

What are the fixatives according to COMPOSITION?

SC

A
  • Simple fixatives
  • Compound fixatives
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83
Q

These are made up of only one component substance

A

Simple fixatives

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84
Q

These are those that are made up of two or more fixatives which have been added together to obtain the optimal combined effect of their individual actions upon the cells and tissue constituents

A

Compound fixatives

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85
Q

What are the fixatives under Simple fixatives?

MA

A
  • Aldehydes
  • Metallic Fixatives
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86
Q

What are the aldehyde fixatives?

FG

A
  • Formaldehyde
  • Glutaraldehyde
87
Q

What are the metallic fixatives?

MR. LEAD HEAT CHROMATE

A
  • mercuric chloride
  • heat
  • lead fixatives
  • chromate fixatives
88
Q

What are the chromate fixatives?

CP

A
  • Chromic acid
  • Potassium dichromate
89
Q

What are the lead fixatives?

AAAPO

A
  • Acetic acid
  • acetone
  • alcohol
  • Picric acid
  • Osmium tetroxide (osmic acid)
90
Q

What are the fixatives according to ACTION?

MC

A
  • MICROANATOMICAL FIXATIVES
  • CYTOLOGICAL FIXATIVES
91
Q

These are those that permit the general microscopic study of tissue structures WITHOUT ALTERING the structural pattern and normal intercellular relationship of the tissues in question

A

MICROANATOMICAL FIXATIVES

92
Q

These fixatives are those that preserve specific parts and particular microscopic elements of the cell itself

A

cytological fixatives

93
Q

What are the MICROANATOMICAL FIXATIVES?

10 -10, B-B, Z-Z, H-F

A
  • 10% Formol saline
  • 10% neutral buffered formalin
  • Brasil’s solution
  • Bouin’s solution
  • Heidenhain’s Susa
  • Formol sublimate (formol corrosive)
94
Q

What are the MICROANATOMICAL FIXATIVES?

10 -10, B-B, Z-Z, H-F

A
  • 10% Formol saline
  • 10% neutral buffered formalin
  • Brasil’s solution
  • Bouin’s solution
  • Heidenhain’s Susa
  • Formol sublimate (formol corrosive)
95
Q

What are the cytological fixatives?

CHN

A
  • Nuclear fixatives
  • Cytoplasmic fixatives
  • histochemical fixatives
96
Q

These are those that preserve the NUCLEAR structures (e.g., chromosomes) in particular

A

Nuclear fixatives

97
Q

Nuclear fixatives usually contain what as their primary component?

A

glacial acetic acid

98
Q

Glacial acetic acid is a primary component in nuclear fixatives due to what?

A

due to its AFFINITY for nuclear chromatin

99
Q

These fixatives have a pH of 4.6 or less

A

nuclear fixatives

100
Q

What are the nuclear fixatives?

FBNCCH

A
  • Flemming’s fluid
  • Carnoy’s fluid
  • Bouin’s fluid
  • Newcomer’s fluid
  • Heidenhain’s Susa
  • Clarke’s fixatives
101
Q

This nuclear fixative has been found to react with viruses, and cause the loss of their infective power

A

MERCURIC CHLORIDE

102
Q

At temperatures normally used for fixation (20C), DNA and RNA do not react with formaldehyde

true or false

A

true

103
Q

If reaction mixtures are heated, to about 45C in case of DNA and 65C in case of RNA, reaction begins to take place

TRUE OR FALSE

A

FALE

45C RNA; 65C DNA

103
Q

If reaction mixtures are heated, to about 45C in case of DNA and 65C in case of RNA, reaction begins to take place

TRUE OR FALSE

A

FALE

45C RNA; 65C DNA

104
Q

If reaction mixtures are heated, to about 45C in case of RNA and 65C in case of DNA, reaction begins to take place due to what?

A

due to the coiling of DNA and RNA

105
Q

Coiling is also observed in glutaraldehye and nucleic acids

true or false

A

true

106
Q

What percent is lost during usual fixation when aldehydes continue to react with nucleic acids longer than after they are placed in fixative?

A

30%

107
Q

These fixatives are commonly used fixatives for nucleic acids

m-etha-noy

A
  • methanol
  • ethanol
  • carnoy’s
108
Q

The presence of WHAT is known to be essential for the maximum precipitation of nucleic acids FROM ALCOHOL?

A

SALTS

109
Q

In this state, there is no significant difference between fixation in neutral buffered formaldehyde, B5, Hollande, and zinc formaldehyde

A

IN SITU HYBRIDIZATION

110
Q

This fixative appears to give the most usable DNA fragments for polymerase chain reactions (PCR)

A

ETHANOL

111
Q

This fixative limits the size of fragments which can be retrieved

A

formaldehyde

112
Q

These are limited in its use for PCR

BA

A
  • Bouin’s sol’n
  • acid fixed tissue
113
Q

These fixatives are those that preserve cytoplasmic structures in particular

A

cytoplasmic fixatives

114
Q

These fixatives must never contain glacial acetic acid

A

cytoplasmic fixatives

115
Q

Using glacial acetic acid in cytoplasmic fixatives destroys what?

A

destroys mitochondria and Golgi bodies of the cytoplasm

116
Q

ctyoplasmic fixatives have a pH of 4.6

true or false

A

false

more than 4.6

117
Q

What are the cytoplasmic fixatives?

FFORH

A
  • Flemming’s fluid withoud HAC
  • Formalin with “post-chroming”
  • Orth’s fluid
  • Regaud’s fluid
  • Helly’s fluid
118
Q

Regaud’s fluid is also called …

A

Muller’s fluid

119
Q

For RNA, what precipitant fixatives give the best QUANTITATIVE results using FROZEN tissues as the standard

A

ethanol, acetone

120
Q

These are the fixatives that preserve the chemical constituents of cells and tissues

A

histochemical fixatives

121
Q

What are the histochemical fixatives?

FANA

A
  • Formol saline 10%
  • Absolute Ethyl Alcohol
  • Newcomer’s Fluid
  • Acetone
122
Q

What should be used for demonstrating lipid in tissues?

A

Cryostat or frozen section followed by a general lipid stain

123
Q

Fixatives containing these fixatives can be effective for preservation of lipids in cryostat sections

A
  • mercuric chloride
  • potassium dichromate
124
Q

in general, phospholipids contain what?

A

amino groups

125
Q

Phospholipids are fixed by what?

A

by aldehydes

126
Q

This fixatives reacts with unsaturated fatty acids during histological fixations

A

formaldehyde

127
Q

This can be used to preserve phospholipids

A

Baker’s formol-calcium

128
Q

Improved ultrastructural demonstration of lipids has been achieved by what?

A

by post-fixing in IMIDAZOLE OSMIUM TETROXIDE

129
Q

This fixes cholesterol for ultrastructural demonstration

A

DIGITONIN

130
Q

What is fixed by digitonin for ultrastructural demonstration

A

cholesterol

131
Q

These fixatives are generally recommended for glycogen fixation

A

alcoholic fixatives

132
Q

This can be demostrated satsfactorily for diagnosis, although losses of this can be high (60%-805) in aqueous solution

A

glycogen

133
Q

This is a better fiative in HUMAN SKIN compared with NETRUAL BUFFERED FORMALDEHYDE

A

Alcoholic formaldehyde

134
Q

Alcoholic formaldehyde is a better fixative in human skin compared with neutral buffered formaldehyde

true or false

A

true

135
Q

These are the most commonly used fixatives for AMINO ACID HISTOCHEMISTRY

A
  • neutral buffered formol saline
  • formaldehyde vapor
136
Q

The most useful fixatives for preserving glycogen are alcohol-based

true or false

A

true

137
Q

These are alcohol-based fixatives that are the most useful for preserving glycogen

A
  • Rossman’s fluid
  • cold absolute alcohol
138
Q

This is essential when processing tissues from patients with glycogen storage diseases.

A
  • Rossman’s fluid
  • cold absolute alcohol
  • glycogen fixatives
139
Q

There is better retention of glycogen if the section is coated with what?

A

celloidin

140
Q

These aldehyde fixatives have been particularly useful for electron cytochemistry

A
  • Karnovsky’s paraformaldehyde-glutaraldehyde
  • acrolein
141
Q

This is another aldehyde which has been introduced as a mixture with glutaraldehyde and formaldehyde

A

Acrolein

142
Q

This fixative penetrates tissues rapidly, preserves morphology and enzyme activity at low concentrations

A

Acrolein

143
Q

This may be useful for immersion fixation of surgical biopsies

A

acrolein

144
Q

These fixatives are satisfactory for routine paraffin sections, electron microscopy, histochemical and enzyme studies

A

Aldehyde

145
Q

Formalin is also called

A

formaldehyde

146
Q

One of the most widely used fixatives

A

10% formalin

147
Q

10% formalin is made from what

A

formaldehyde

148
Q

This is a gas produced by the oxidation of methyl aalcohol

A

10% formalin

149
Q

10% FORMALIN IS SOLUBLE IN WATER TO THE EXTENT OF 37-40% weight in volume

true or false

A

true

150
Q

The commercially available solution of formaldehyde contains 35-40% gas by weight

true or false

A

true

151
Q

This is unsatisfactory for routine fixation since high formaldehyde concentrates tend to overharden the outer layer of the tissue and affecting staining adversely

A

Pure stock solution of 40% formalin

152
Q

Formaldehyde is commonly used as a 2% solution, giving 10% formalin for tissue fixation

true or false

A

false

4%

153
Q

Formaldehyde is commonly used as a 2% solution, giving 10% formalin for tissue fixation

true or false

A

false

4%

154
Q

dilution for formalin

A

1:10 or 1:20

155
Q

What is the usual fixation time for formalin

A

24 hours

156
Q

Formaldehyde is usually buffered to what pH?

A

pH 7 with phosphate buffer

157
Q

It is a “tolerant’ fixative, used for mailing specimen

A

formalin

158
Q

This is a simple microanatomical fixative made up of saturdated formaldehyde (40% by weight volume)

A

10% formol saline

159
Q

Dilution of 10% formol saline

A

10% with sodium chloride

160
Q

this is recommended for fixation of central nervous tissues

A

10% formol saline

161
Q

this is recommended for general post mortem tissues for histochemical examinations

A

10% formol saline

162
Q

Fixation time of 10% formol saline at 35C

A

24 HOURS

163
Q

Fixation of 10% formol saline at 20-25C

A

48 hrs

164
Q

It penetrates and fixes tissues evenly

A

10% formol saline

165
Q

It preserves microanatomic and cytologic details with minimum shrinkage and distortion

A

10% formol saline

166
Q

It preserves enzymes and nucleoproteins

A

10% formol saline

167
Q

10% Neutral Buffered Formaline is also called

A

Phosphate Buffered formalin

168
Q

10% NBF has a pH of 7

true or false

A

true

169
Q

This is recommended for preservation and storage of surgical, post-mortwm, and research specimens

A

10% NBF

170
Q

wHAT IS THE FIATION TIME OF PHOSPHATE BUFFERED FORMALIN?

A

4-24 hours

171
Q

It is the best fixative for tissues containing iron pigments and for elastic fibers

A

10% NBF

172
Q

Formol corrosive is also called …

A

formol sublimate

173
Q

This solution is recommended for routine post mortem-tissues

A

formol-mercuric chloride

174
Q

What is the ixation time of formol corrsive?

A

3-24 hours

175
Q

It penetrates small pieces of tissues rapidly

A

formol sublimate

176
Q

Alcoholic formalin is also called …

A

Gendre’s fixative

177
Q

This fixative is good for preservation of glycogen and micro-incineration

A

Gendre’s fixation

178
Q

It is used to fix sputum

A

Alcoholic formalin

179
Q

It causes partial lysis of RBC

A

ALCOHOLIC FORMALIN

180
Q

This is most effective at cross linking

A

glutaraldehyde

181
Q

Made up of two formaldehyde residues, linked by three carbon chains

A

glutaraldehyde

182
Q

it acts in a manner similar to formaldehyde

A

glutaraldehyde

183
Q

It is followed by secondary fixation in osmium tetroxide. It is satisfactory for electron microscopy

A

Buffered glutaraldehyde

184
Q

It is the most common metallic fixative

A

Mercuric chloride

185
Q

It is widely used as a secondary fixative reacting with a number of amino acid residues and accompanied by spectroscopic changes

A

Mercuric chloride

186
Q

It penetrates poorly and produces shrinkages of tissues

A

mercuric chloride

187
Q

Contains black precipitates of mercury

A

mercuric chloride

188
Q

these are removed from deparaffinized sections before staining

A

mercuric chloride

189
Q

Trichrome staining is excellent with this fixative

A

mercuric choride

190
Q

It is recommended for renal tissues, fibrin, connective tissues, and muscles

A

merucric chloride

191
Q

Is made up of mercuric chloride stock solution to which glacial acetic acid has been added just before its use to prevent turbidity and formation of a dark precipitate

A

ZENKER’S FLUID

192
Q

It is a good general fixaive for adequate preservation of all kinds of tissues

A

Zenker’s fluid

193
Q

It is recommended for fixing small pieces of liver, spleen, connective tisse fibers and nuclei

A

Zenker’s fluid

194
Q

What is the fixation time of Zekner’s fluid?

A

12-24 hours

195
Q

what is the fixation time of Zenker-formol?

A

12-24 hrs

196
Q

zenker-formol is also called

A

Helly’s solution

197
Q

It is an excellent microanatomic fixative for pituitary gland, bone marriw, and blood containing organs such as spleen and liver

A

Zenker-formol

198
Q

Brown pigment are produced if tissues are allowed to stay in the fixative for more than 24 hrs due to RBC lysis

A

Zenker-formol

199
Q

The brown pigments produced in Zenker-formol may be removed by immersing the tissue in what?

A
  • saturated alcoholic picric acid
  • sodium hydroxide
200
Q

This is recommended mainly for tumor biopsies especially of the skin; it is an excellent ctyologic fixative

A

Heidenhan’s Susa Solution

201
Q

What is the fixation time of Heidenhan’s Susa sol’n?

A

3-12 hrs

202
Q

This is commonly used for bone marrow biopies

A

B-5 Fixative

203
Q

It precipitates all proteins and adequately preserves carbohydrates

A

chromic acid

204
Q

It is a strong oxidizng agent, hence, a strong reducing agentmust be added to chrome-containing fixatives before use in order to prevent counteracting effects

A

chromic acid

205
Q

It preserves lipids

A

Potassium dichromate

206
Q

It preserves mitochondria

A

Potassium dichromate

207
Q

It fixes but does not precipitate cytoplasmic structures

A

potassium dichromate

208
Q

It is recommended for demonstration of chromatin, mitochondria, mitotic figures, golgi bodies, RBC and colloid-containing tissues

A

Regaud’s/Muller’s fluid

209
Q

What is the fixation time of Regud’s

A

12-48 hrs

210
Q

it is recommended for tudy of early degenerative processes and tissue necrosis

A

Orth’s fluid

211
Q

It demonstrates rickettsiae and other bacteria

A

Orth’s fluid

212
Q

It preserves myelin better than buffered formalin

A

orth’s fluid

213
Q

What is the fixation time of orth’s fluid

A

36-72 hrs

214
Q

It is recommended for acid mucopolysaccharides

A

Lead fixatives

215
Q

It fixes connective tissue mucin

A

lead fixatives

216
Q

It takes up CO2 to form insolube lead carbonate

A

lead fixatives

217
Q

This dyes the tissues, but the yellow color may be removed by treatment with another acid dye or lithium carbonate

A

picric acid

218
Q

It is highly explosve when dry

A

picric acid

HISTOPATH LEC (7 decks)

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