FIXATION 2012 GREGORIOS Flashcards
(222 cards)
1
Q
It is the art and science performed by the histotechnologist to produce a tissue section of good quality
A
Histotechnology
2
Q
What is the first and most critical step in histotechnology
A
fixation
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
4
Q
what is the cell composed of?
A
- proteins
- lipids
- carbohydrates
- organic
- inorganic
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
6
Q
in fixation, what are being preserved?
A
- shape
- structure
- intercellular relationships
- chemical constituents
7
Q
Fixation prevents the what of tissues after removal from the body?
A
- degeneration
- putrefaction
- decomposition
- distortion
8
Q
What happens to all vital cellular processes when the tissue is placed in a fixative?
A
they stop
9
Q
The weak chemical associations are changed into what that will not break down with further histologic handling
A
changed into stable complexes
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
11
Q
How does fixation preserve the tissue?
A
by stopping all cellular activities
12
Q
leaving the tissue in water, a hypertonic solution, will cause the cell to swell
True or false
A
false
hypotonic
13
Q
leaving the tissue in water, a hypertonic solution, will cause the cell to swell
True or false
A
false
hypotonic
14
Q
What happens to the cell if the tissue is left in water (hypotonic solution)?
A
the cell will swel
15
Q
What happens to the cell if the tissue is left in water (hypotonic solution)?
A
the cell will swell
16
Q
a strong salt (hypertonic solution) will the cell to swell
True or false
A
false
cell will shrink
17
Q
a strong salt (hypertonic solution) will the cell to swell
True or false
A
false
cell will shrink
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
19
Q
cell death is caused by the deprivation of what?
A
deprivation of oxygen and nutrition
20
Q
Every cell in the body has a structure or “suicide sac” within its cytoplasm called what?
A
lysosome
21
Q
this contains hydrolytic enzymes that are released when the integrity of the cell is destroyed
A
lysosome
22
Q
postmortem decomposition is called …
A
autolysis
23
Q
this occurs due to the action of these hydrolytic enzymes
A
autolysis
24
Q
Fixation prevents autolysis
true or false
A
true
25
How does fixation prevent autolysis?
by inactivating the lysosomal enzymes, or by chemically altering, stabilizing, and making the tissue components insoluble
26
Decomposition is also called ...
putrefaction
27
Decomposition is also called ...
putrefaction
27
Decomposition is also called ...
putrefaction
27
Decomposition is also called ...
putrefaction
28
Decomposition is also called ...
putrefaction
29
Fixation also protects the tissue from further putrefaction after death due to what?
due to bacterial or fungal colonization and overgrowth
30
Fixation also protects the tissue from further putrefaction after death due to what?
due to bacterial or fungal colonization and overgrowth
31
What are the two basic mechanisms involved in fixation?
1. additive fixation
2. non additive fixation
32
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
ADDITIVE FIXATION
33
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?
by forming cross-links or molecular complexes
34
What are examples of additive fixation?
- formalin
- mercury
- osmium tetroxide
35
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
NON ADDITIVE FIXATION
36
What is an example of a non additive fixation?
alcoholic fixatives
37
What are the 6 MAIN FACTORS INVOLVED IN FIXATION
| CTTHOD
1. Concentration
2. Temperature
3. Thickness of section
4. Hydrogen Ion concentration
5. Osmolality
6. Duration of Fixation
38
Satisfactory fixation occurs between what pH levels?
pH 6 and pH 8
39
Fixation of surgical specimens is traditionally carried out at what temperature?
at room temperature
40
Many laboratories use tissue processors that work at what temperature?
40C
41
For electron microscopy and some histochemistry the ideal temperature is what?
0-4C
42
What kind of cells are best fixed at room temperature even for electron microscopy?
mast cells
43
nucleic acids do not react with fixatives to any extent at 4C
| True or false
FALSE
| at room temperature
43
nucleic acids do not react with fixatives to any extent at 4C
| True or false
FALSE
| at room temperature
44
Nucleic acids do not react with chemical reactions including those involved in fixation are more rapid at higher temperatures
| true or false
true
45
Formalin is heated at what temperature is sometimes used for rapid fixation of VERY URGENT biopsy specimens, although the risk of tissue distortionis increased?
60C
46
Formalin at what temperature can be used to fix tissues with tuberculosis?
100C
47
What must be the thickness of the section for electron microscopy?
1 to 2 mm^2
48
what is the thickness of the section in light microscopy?
2 cm^2
49
if the tissue must be thin, the measurement must be how thin for light microscopy?
0.4 cm
50
Large solid tissue, such as UTERUS, should not be opened or sliced thinly
| True or false
false
| should be opened or sliced thinly
51
Large solid tissue, such as UTERUS, should not be opened or sliced thinly
| True or false
false
| should be opened or sliced thinly
52
Brain is usually suspended in parts
| True or False
FALSE
| suspended whole
53
Brain is usually suspended in parts
| True or False
FALSE
| suspended whole
54
Brain is usually suspended whole in what fixative?
10% buffered formalin
55
Brain is usually suspended whole in 10% buffered formalin for how long?
2-3 weeks
56
What kind of solution gives rise to cell shrinkage?
Hypertonic solution
57
these fixatives causes cell swelling and poor fixation
Isotonic as well as hypotonic fixatives
58
Regarding osmolality, best results are usually obtained using what solution?
SLIGHTLY HYPERTONIC SOLUTIONS
59
Regarding osmolality, best results are usually obtained using what solution?
SLIGHTLY HYPERTONIC SOLUTIONS
60
How many mOsm is a slightly hypertonic solution?
400 - 450 mOsm
61
Isotonic solutions are 340 mOsm
| True or false
TRUE
62
What is commonly added to osmium tetroxide fixatives for electron microscopy?
Sucrose
63
Sucrose is commonly added to what fixative for electron microscopy?
osmium tetroxide
64
Sucrose is commonly added to osmium tetroxide fixative for what?
electron microscopy
65
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
TRUE
66
For glutaraldehyde fixatives, the vehicle osmolality should be more or less 300 mOsm
| True or false
true
67
This is normally used as a 10% solution
Formaldehyde
68
Glutaraldehyde is normally used as a 3% solution
| True or false
true
69
The presence of a what causes polymerization of the aldehyde, with consequent decrease in its effective concentration
The presence of a buffer
70
The presence of a buffer causes what?
Polymerization of the aldehyde
71
High concentrations of glutaraldehyde have been found to be an ideal concentration for immunoelectron microscopy
| True or false
FALSE
| Low concentrations
72
High concentrations of glutaraldehyde have been found to be an ideal concentration for immunoelectron microscopy
| True or false
FALSE
| Low concentrations
73
What is the ideal concentration of glutaraldehyde in immunoelectron microscopy?
low concentrations of glutaraldehyde (0.25%)
74
Primary fixation in buffered formalin is usually carried out for how long?
2-6 hours during the day the specimen is obtained
75
A specimen in primary fixation in buffered formalin may remain in fixative over the weekend without much adverse effect
| True or false
true
76
Most of the formalin can be washed out after fixation in how many hours?
24 hours
77
Prolonged fixation may cause what?
* shrinkage
* hardening of tissue
* may severely inhibit enzyme activity and immunological reactions
78
Prolonged fixation may cause what?
* shrinkage
* hardening of tissue
* may severely inhibit enzyme activity and immunological reactions
79
Washing of the tissue in running water considerably restores the activity of some enzymes
| true or false
true
80
For electron microscopy, it is recommended that diced tissues be fixed for how many hours?
3 hours
81
For electron microscopy, after fixing the diced tissues for 3 hours, where should it be placed?
in a holding buffer
82
What are the fixatives according to COMPOSITION?
| SC
- Simple fixatives
- Compound fixatives
83
These are made up of only one component substance
Simple fixatives
84
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
Compound fixatives
85
What are the fixatives under Simple fixatives?
| MA
- Aldehydes
- Metallic Fixatives
86
What are the aldehyde fixatives?
| FG
- Formaldehyde
- Glutaraldehyde
87
What are the metallic fixatives?
| MR. LEAD HEAT CHROMATE
- mercuric chloride
- heat
- lead fixatives
- chromate fixatives
88
What are the chromate fixatives?
| CP
- Chromic acid
- Potassium dichromate
89
What are the lead fixatives?
| AAAPO
- Acetic acid
- acetone
- alcohol
- Picric acid
- Osmium tetroxide (osmic acid)
90
What are the fixatives according to ACTION?
| MC
- MICROANATOMICAL FIXATIVES
- CYTOLOGICAL FIXATIVES
91
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
MICROANATOMICAL FIXATIVES
92
These fixatives are those that preserve specific parts and particular microscopic elements of the cell itself
cytological fixatives
93
What are the MICROANATOMICAL FIXATIVES?
| 10 -10, B-B, Z-Z, H-F
- 10% Formol saline
- 10% neutral buffered formalin
- Brasil's solution
- Bouin's solution
- Heidenhain's Susa
- Formol sublimate (formol corrosive)
94
What are the MICROANATOMICAL FIXATIVES?
| 10 -10, B-B, Z-Z, H-F
- 10% Formol saline
- 10% neutral buffered formalin
- Brasil's solution
- Bouin's solution
- Heidenhain's Susa
- Formol sublimate (formol corrosive)
95
What are the cytological fixatives?
| CHN
- Nuclear fixatives
- Cytoplasmic fixatives
- histochemical fixatives
96
These are those that preserve the NUCLEAR structures (e.g., chromosomes) in particular
Nuclear fixatives
97
Nuclear fixatives usually contain what as their primary component?
glacial acetic acid
98
Glacial acetic acid is a primary component in nuclear fixatives due to what?
due to its AFFINITY for nuclear chromatin
99
These fixatives have a pH of 4.6 or less
nuclear fixatives
100
What are the nuclear fixatives?
| FBNCCH
- Flemming's fluid
- Carnoy's fluid
- Bouin's fluid
- Newcomer's fluid
- Heidenhain's Susa
- Clarke's fixatives
101
This nuclear fixative has been found to react with viruses, and cause the loss of their infective power
MERCURIC CHLORIDE
102
At temperatures normally used for fixation (20C), DNA and RNA do not react with formaldehyde
| true or false
true
103
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
FALE
| 45C RNA; 65C DNA
103
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
FALE
| 45C RNA; 65C DNA
104
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?
due to the coiling of DNA and RNA
105
Coiling is also observed in glutaraldehye and nucleic acids
| true or false
true
106
What percent is lost during usual fixation when aldehydes continue to react with nucleic acids longer than after they are placed in fixative?
30%
107
These fixatives are commonly used fixatives for nucleic acids
| m-etha-noy
- methanol
- ethanol
- carnoy's
108
The presence of WHAT is known to be essential for the maximum precipitation of nucleic acids FROM ALCOHOL?
SALTS
109
In this state, there is no significant difference between fixation in neutral buffered formaldehyde, B5, Hollande, and zinc formaldehyde
IN SITU HYBRIDIZATION
110
This fixative appears to give the most usable DNA fragments for polymerase chain reactions (PCR)
ETHANOL
111
This fixative limits the size of fragments which can be retrieved
formaldehyde
112
These are limited in its use for PCR
| BA
- Bouin's sol'n
- acid fixed tissue
113
These fixatives are those that preserve cytoplasmic structures in particular
cytoplasmic fixatives
114
These fixatives must never contain glacial acetic acid
cytoplasmic fixatives
115
Using glacial acetic acid in cytoplasmic fixatives destroys what?
destroys mitochondria and Golgi bodies of the cytoplasm
116
ctyoplasmic fixatives have a pH of 4.6
| true or false
false
| more than 4.6
117
What are the cytoplasmic fixatives?
| FFORH
- Flemming's fluid withoud HAC
- Formalin with "post-chroming"
- Orth's fluid
- Regaud's fluid
- Helly's fluid
118
Regaud's fluid is also called ...
Muller's fluid
119
For RNA, what precipitant fixatives give the best QUANTITATIVE results using FROZEN tissues as the standard
ethanol, acetone
120
These are the fixatives that preserve the chemical constituents of cells and tissues
histochemical fixatives
121
What are the histochemical fixatives?
| FANA
- Formol saline 10%
- Absolute Ethyl Alcohol
- Newcomer's Fluid
- Acetone
122
What should be used for demonstrating lipid in tissues?
Cryostat or frozen section followed by a general lipid stain
123
Fixatives containing these fixatives can be effective for preservation of lipids in cryostat sections
- mercuric chloride
- potassium dichromate
124
in general, phospholipids contain what?
amino groups
125
Phospholipids are fixed by what?
by aldehydes
126
This fixatives reacts with unsaturated fatty acids during histological fixations
formaldehyde
127
This can be used to preserve phospholipids
Baker's formol-calcium
128
Improved ultrastructural demonstration of lipids has been achieved by what?
by post-fixing in IMIDAZOLE OSMIUM TETROXIDE
129
This fixes cholesterol for ultrastructural demonstration
DIGITONIN
130
What is fixed by digitonin for ultrastructural demonstration
cholesterol
131
These fixatives are generally recommended for glycogen fixation
alcoholic fixatives
132
This can be demostrated satsfactorily for diagnosis, although losses of this can be high (60%-805) in aqueous solution
glycogen
133
This is a better fiative in HUMAN SKIN compared with NETRUAL BUFFERED FORMALDEHYDE
Alcoholic formaldehyde
134
Alcoholic formaldehyde is a better fixative in human skin compared with neutral buffered formaldehyde
| true or false
true
135
These are the most commonly used fixatives for AMINO ACID HISTOCHEMISTRY
- neutral buffered formol saline
- formaldehyde vapor
136
The most useful fixatives for preserving glycogen are alcohol-based
| true or false
true
137
These are alcohol-based fixatives that are the most useful for preserving glycogen
- Rossman's fluid
- cold absolute alcohol
138
This is essential when processing tissues from patients with glycogen storage diseases.
- Rossman's fluid
- cold absolute alcohol
- glycogen fixatives
139
There is better retention of glycogen if the section is coated with what?
celloidin
140
These aldehyde fixatives have been particularly useful for electron cytochemistry
- Karnovsky's paraformaldehyde-glutaraldehyde
- acrolein
141
This is another aldehyde which has been introduced as a mixture with glutaraldehyde and formaldehyde
Acrolein
142
This fixative penetrates tissues rapidly, preserves morphology and enzyme activity at low concentrations
Acrolein
143
This may be useful for immersion fixation of surgical biopsies
acrolein
144
These fixatives are satisfactory for routine paraffin sections, electron microscopy, histochemical and enzyme studies
Aldehyde
145
Formalin is also called
formaldehyde
146
One of the most widely used fixatives
10% formalin
147
10% formalin is made from what
formaldehyde
148
This is a gas produced by the oxidation of methyl aalcohol
10% formalin
149
10% FORMALIN IS SOLUBLE IN WATER TO THE EXTENT OF 37-40% weight in volume
| true or false
true
150
The commercially available solution of formaldehyde contains 35-40% gas by weight
| true or false
true
151
This is unsatisfactory for routine fixation since high formaldehyde concentrates tend to overharden the outer layer of the tissue and affecting staining adversely
Pure stock solution of 40% formalin
152
Formaldehyde is commonly used as a 2% solution, giving 10% formalin for tissue fixation
| true or false
false
| 4%
153
Formaldehyde is commonly used as a 2% solution, giving 10% formalin for tissue fixation
| true or false
false
| 4%
154
dilution for formalin
1:10 or 1:20
155
What is the usual fixation time for formalin
24 hours
156
Formaldehyde is usually buffered to what pH?
pH 7 with phosphate buffer
157
It is a "tolerant' fixative, used for mailing specimen
formalin
158
This is a simple microanatomical fixative made up of saturdated formaldehyde (40% by weight volume)
10% formol saline
159
Dilution of 10% formol saline
10% with sodium chloride
160
this is recommended for fixation of central nervous tissues
10% formol saline
161
this is recommended for general post mortem tissues for histochemical examinations
10% formol saline
162
Fixation time of 10% formol saline at 35C
24 HOURS
163
Fixation of 10% formol saline at 20-25C
48 hrs
164
It penetrates and fixes tissues evenly
10% formol saline
165
It preserves microanatomic and cytologic details with minimum shrinkage and distortion
10% formol saline
166
It preserves enzymes and nucleoproteins
10% formol saline
167
10% Neutral Buffered Formaline is also called
Phosphate Buffered formalin
168
10% NBF has a pH of 7
| true or false
true
169
This is recommended for preservation and storage of surgical, post-mortwm, and research specimens
10% NBF
170
wHAT IS THE FIATION TIME OF PHOSPHATE BUFFERED FORMALIN?
4-24 hours
171
It is the best fixative for tissues containing iron pigments and for elastic fibers
10% NBF
172
Formol corrosive is also called ...
formol sublimate
173
This solution is recommended for routine post mortem-tissues
formol-mercuric chloride
174
What is the ixation time of formol corrsive?
3-24 hours
175
It penetrates small pieces of tissues rapidly
formol sublimate
176
Alcoholic formalin is also called ...
Gendre's fixative
177
This fixative is good for preservation of glycogen and micro-incineration
Gendre's fixation
178
It is used to fix sputum
Alcoholic formalin
179
It causes partial lysis of RBC
ALCOHOLIC FORMALIN
180
This is most effective at cross linking
glutaraldehyde
181
Made up of two formaldehyde residues, linked by three carbon chains
glutaraldehyde
182
it acts in a manner similar to formaldehyde
glutaraldehyde
183
It is followed by secondary fixation in osmium tetroxide. It is satisfactory for electron microscopy
Buffered glutaraldehyde
184
It is the most common metallic fixative
Mercuric chloride
185
It is widely used as a secondary fixative reacting with a number of amino acid residues and accompanied by spectroscopic changes
Mercuric chloride
186
It penetrates poorly and produces shrinkages of tissues
mercuric chloride
187
Contains black precipitates of mercury
mercuric chloride
188
these are removed from deparaffinized sections before staining
mercuric chloride
189
Trichrome staining is excellent with this fixative
mercuric choride
190
It is recommended for renal tissues, fibrin, connective tissues, and muscles
merucric chloride
191
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
ZENKER'S FLUID
192
It is a good general fixaive for adequate preservation of all kinds of tissues
Zenker's fluid
193
It is recommended for fixing small pieces of liver, spleen, connective tisse fibers and nuclei
Zenker's fluid
194
What is the fixation time of Zekner's fluid?
12-24 hours
195
what is the fixation time of Zenker-formol?
12-24 hrs
196
zenker-formol is also called
Helly's solution
197
It is an excellent microanatomic fixative for pituitary gland, bone marriw, and blood containing organs such as spleen and liver
Zenker-formol
198
Brown pigment are produced if tissues are allowed to stay in the fixative for more than 24 hrs due to RBC lysis
Zenker-formol
199
The brown pigments produced in Zenker-formol may be removed by immersing the tissue in what?
- saturated alcoholic picric acid
- sodium hydroxide
200
This is recommended mainly for tumor biopsies especially of the skin; it is an excellent ctyologic fixative
Heidenhan's Susa Solution
201
What is the fixation time of Heidenhan's Susa sol'n?
3-12 hrs
202
This is commonly used for bone marrow biopies
B-5 Fixative
203
It precipitates all proteins and adequately preserves carbohydrates
chromic acid
204
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
chromic acid
205
It preserves lipids
Potassium dichromate
206
It preserves mitochondria
Potassium dichromate
207
It fixes but does not precipitate cytoplasmic structures
potassium dichromate
208
It is recommended for demonstration of chromatin, mitochondria, mitotic figures, golgi bodies, RBC and colloid-containing tissues
Regaud's/Muller's fluid
209
What is the fixation time of Regud's
12-48 hrs
210
it is recommended for tudy of early degenerative processes and tissue necrosis
Orth's fluid
211
It demonstrates rickettsiae and other bacteria
Orth's fluid
212
It preserves myelin better than buffered formalin
orth's fluid
213
What is the fixation time of orth's fluid
36-72 hrs
214
It is recommended for acid mucopolysaccharides
Lead fixatives
215
It fixes connective tissue mucin
lead fixatives
216
It takes up CO2 to form insolube lead carbonate
lead fixatives
217
This dyes the tissues, but the yellow color may be removed by treatment with another acid dye or lithium carbonate
picric acid
218
It is highly explosve when dry
picric acid
