Fixation Flashcards
1
Q
Most critical step in preserving tissue
A
Fixation
2
Q
initial step in tissue processing
A
Fixation
3
Q
Purpose of fixation
A
Killing, penetration, and Hardening
4
Q
Primary goal of Fixation
A
Preserve tissue and cells
5
Q
Secondary Goal of fixation
A
- Hardens tissue
- Protect tissue from further trauma
6
Q
Physical Method of Fixation
A
Heat Fixation
Microwave Fixation
7
Q
Heat fixation is usually used in
A
Microbiological Section (Bacterial smear)
For FROZEN section only
8
Q
Neurochemical substance preserve by Microwave technique
A
Acetylcholine
9
Q
Use of fixative agent is under what method
A
Chemical Method
10
Q
Fixation is usually carried out at what temp
A
Room temperature
11
Q
Formalin temp. Used for urgent biopsies
A
Formalin @60
12
Q
Formalin @100 deg. Cel. Is required for
A
Fixing tissues with TUBERCULOSIS
13
Q
Required size for tissue
A
3x2 cm
14
Q
Required thickness for tissue
A
3-5mm
15
Q
Common osmolality requirement used in Lab
A
Isotonic
16
Q
Concentration used in Formalin
A
10% Formalin
17
Q
Ideal time to perform fixation
A
20-30 mins following interruption of blood supply
18
Q
Required osmolality in fixation based on book
A
Slightly Hypertonic
19
Q
Concentration used in Formalin
A
10%
20
Q
Measurements to form 10% formalin
A
100 ml 37%-40% formalin + 900 mL distilled water
21
Q
Disdvantage of formalin
A
Easy to precipitate
22
Q
Substance added to avoid precipitation of formalin
A
Add 10% methanol
23
Q
Concentration of glutaraldehyde for EM
A
3%
24
Q
Causes for retarded fixation
A
Blood
Mucus
Fats
Large tissues
25
Causes for accelerated fixation
Heat (37-56)
Agitation
26
Common volume ratio of fixative to tissue
20:1
27
Osmium tetroxide volume
5-10x:1
28
Hallow organ must be packed with _____
Cotton
29
Human brain must undergo
Intravascular perfusion
30
Washing out of blood from Human brain uses what fixative
Ringers lactate
31
For large organ such as Uterine, cervix, fibroid it must undergo
LENDRUM’S METHOD
32
Lundrum’s method fixative contains
4% aqueous phenol (1-3 days)
33
Effect of fixative in tissues
Harden tissues
Make cell resistant to damage
Act as accentuators and mordants
34
Incomplete washing may cause
Precipitation of artefacts
35
Too hard and brittle tissues is due to
Overfixation
36
Too soft tissue may be due to
Underfixation
37
Wrong choice of fixative may lead to
Loss of soluble substance in fixing agent
38
Factos needed to be considered when choosing fixatives
Needed for an immediate exam
Type of specimen
Structure to be studied
Staining technique
Type of section to be made
39
Fixative used in brain tissues
Carnoys
Acetone
40
fixative that cannot be used in kidney/spleen
Bouins
41
Fixative used for lipases/enxymes
Acetone
42
Used to preserve glycogen
Brasil’s
43
Mechanism of action:
Type of fixative that is being absorbed by the tissues
Additive Fixatives
44
Mechanism of Action:
Fixatives that are not being absorbed by the tissues
Non-Additive Fixatives
45
Non-additive fixatives are
Acetone
Alcohol
46
Fixative use for general microscopic study
MICROANATOMICAL
10% formol saline
10% neutral buffered formalin
Heidanhain’s susa
Formol sublimate/formol corrosive
Zenker’s
Bouin’s
Brasil’s
47
Nuclear fixative must contain
Glacial acetic acid
48
Nuclear fixative pH requirement
Less than 4.6 (acidic)
49
Cytoplasmic pH requirement
Not more than 4.6
50
Nuclear fixatives are
Flemmings with Glacial Acetic Acid
Carnoys
Bouin’s
Newcomer’s
Heidenhain’s Susa
51
Cytoplasmic fixatives are
Flemming w/o HAc
Helly’s
Formalin with post chroming
Regaud’s/Moller’s
Orth’s
52
Fixative used to preserve chemical components are called as
HISTOCHEMICAL FIXATIVES
53
Histochemical Fixatives are
NAFA
Newcomer’s
Absolute Ethyl alcohol
10% Formol saline
Acetone
54
A nuclear fixative, considered as Compound fixative that solidifies at 17 deg. Cel.
Glacial Acetic acid
55
What type of fixative is trichroloacetic acid
Compound fixative
56
Tricholoroacetic acid is both used as
Fixative and Decalcifying agent
57
Fixative used at ice cold temperature, ideal for enzymes (lipase, phosphatase)
Acetone
58
Acetone is both used as
Fixative and dehydrating agent
59
Ideal for enzymes and diagnosis of rabies
Acetone
60
Disadvantages of Acetone are
Dissolves fats
Evaporates easily
Raw material for shabu
61
Fixative that is expensive and NOT FAST ACTING used in EM
Osmium tetroxide
62
Osmium tetroxide preserves
Myelin and Peripheral nerves
63
Fixatives with Osmium Tetroxide are
Flemmings with HAc (nuclear)
Flemmings w/o HAc (cytoplasm)
64
Used as Fixative, Stain, DECALCIFYING
Picric Acid
65
Excellent for Glycogen Demonstration
Picric Acid Fixative
66
Disadvantage of Picric Acid
Produced yellow color when used as fixative
67
Remedy for yellow stain while using picric acid
70% alcohol + LITHIUM CARBONATE — washed w/water
70% ethanol + sodium thiosulfate (washed w/ water
68
Fixatives with Picric Acid are
Bouin’s solution
Brasil’s Alcoholic formalin
Hollande’s solution
69
Fixative used in embryo and pituitary biopsies, and endometrial curettings
Bouin’s solution
70
Reason as to why Bouin’s solution is not used in kidneys
Inhibit Feulgen Reaction (dmeonstrate RNA, DNA)
71
Hollande’s solution is used for
GIT biopsies & endocrine tissues
72
Fixative that easily disintegrate and precipitates protein
Alcohol Fixative
73
Alcohol is used both as
Fixative, dehydrating
74
Alcohol is ideal for
Small tissue fragments
75
Disadvantage of Alcohol
Glycogen polymerization
76
Alcohol fixative used for wet and dry smear, BM tissues
Methyl alcohol (100%)
77
Isopropyl alcohol is used for
Touch preparation
78
Ethyl alcohol 50-70% is used for
Blood, tissue film and smear
79
Fixative used for chromosomes and lymph glands; brain tissue
Carnoy’s
80
Considered as a fast-acting fixative
Carnoy’s
81
Used for histochemical and nuclear fixative
Newcomer’s
82
Used for CT mucin and Umbilical cord
Rossman’s solution
83
Most common metallic fixative
Mercuric chloride
84
Ideal staining for mercuric chloride
Trichrome staining
85
Aids in black mercury deposit from mercuric chloride
Alcoholic iodine
86
Component of Zenker’s fluid
Mercuric chloride, Glacial acetic acid
87
Structures preserved by Zenker’s fluid
Liver/spleen, Connective tissues fibers, nuclei
88
Zenker’s formol is also known as
Helly’s fluid
89
Structures preserved by Zenker’s formol
Pituitary gland, BM, other organ with blood supply
90
Component of Zenkers Formol
Potassium dichromate
40% formaldehyde
91
Used for tumor biopsies
Heidenhains susa
92
Component of Heidenhains susa
TCA, HAc, formalin
93
With anhydrous sodium acetate
B5
94
Tissue preserved by B5
Bone marrow
95
Preserves carbohydrates
Chromic acid (1-2%)
96
Potassium dichromate preserves
Lipids and mitochondria
97
Other name for Regaud’s
Moller’s
98
Regauds fixed what structure
Chromatin, golgi bodies, mitotic figures, mitochondria,RBC containing colloid tissues
99
Fixative that preserves ricketssial tissue, necrosis
Orth’s
100
Fixative used for tissue mucin
Lead fixative
101
Fixative for acid mucopolysaccharide
Lead fixative
102
Routinely used fixative
10% formalin
103
Component of 10% formol saline
Sodium chloride
104
Structure preserve by 10% formol saline
- Histochemical
- General post mortem tissue
- CNS tissue
105
Composed with phosphate buffer + 10% formalin
10% neutral buffered saline
106
Structure preserved by 10% neutral buffered saline
Iron pigment
Elastic fiber
107
Component Of formol corrosive
Mercuric chloride + formaldehyde
108
Structure preserve by Formol corrosive
Lipids
Phospholipids
Neutral fats
109
Other term for Alcoholic Formalin
Gendre’s solution
110
Component of Alcoholic formalin
FO-PEG
FOrmadehyde
Picric Acid
95% Ethyl Alcohol
Glutaraldehyde
111
Tissue preserved by alcoholic formalin
Sputum specimen
112
Ideal for EM and histochemistry
Glutaraldehyde
113
Fixatives used in Enzyme Histochemistry
4% formaldehyde
Formol saline
114
Fixatives for EM
POG
Paraformaldehyde
Osmium tetroxide
Glutaraldehyde
115
Smallest aldehyde fixative and fast acting
Glyoxal
116
Fixative used for Electron Histochemistry and Electron Immunocytometry
Karnovsky’s paraformaldehyde-glutaraldehyde
