MODULE 1 - Fixation Flashcards
What are the factors involved in fixation?
Hydrogen ion concentration Temperature Thickness of tissue Osmolality Concentration & Duration of fixation Volume
Usual temperature used in fixation of surgical specimen
Room temperature
Hydrogen ion concentration for fixation
Between pH of 6 and 8
Temperature when using EM and histochemistry
0-4 degrees Celsius
Formalin temperature when fixing tissues with tuberculosis
100 degrees Celsius
Formalin temperature when rapid fixation of urgent biopsies
60 degrees Celsius
Usual temperature when using tissue processors
40 degrees Celsius
Thickness of tissue used in EM
1-2 mm2
Thickness of tissue used in LM
2 cm2
Tissue slices should not be
> 4-5 mm
Thickness of lung specimen
2 cm
In large solid tissues like uterus, it must be _______
open/sliced thinly
In large solid tissues like brain, it should be _______
suspended whole in 10% buffered formalin (2-3 weeks)
This type of solution may be used as holding solutions for tissues
to be transported to frozen sections or kidney biopsies for
special processing
Isotonic solution
Type of solution to be used in fixation
Slightly hypertonic
Hypertonic solution may cause
Cell shrinkage
Hypotonic solution may cause
Cell swelling
Slightly hypertonic solution is between
400-450 mo5m
Amount of glutaraldehyde found to be effective in immunoEM
0.25%
for EM, dyes tissue must be fixed for
3 hours
Prolonged fixation causes
Shrinkage and hardening of tissues
Ratio of fixative to tissue
20:1
Effects of fixative in general
Harden soft and friable tissues Resistant to damage Acts as mordant and accentuator Reduce risk of infection Inhibit bacterial decomposition
2 types of fixative according to composition
Simple and Compound
3 types of fixatives according to action
Histochemical- preserves the chemical components like enzymes
Cytological- preserves parts of nucleus
Microanatomical- as a WHOLE/GENERAL
This allows general microscopic study of tissue structures without
altering the structural pattern and normal intercellular relationships
MICROANATOMICAL
This preserve chemical components of cell and tissue like phosphates and lipases
HISTOCHEMICAL
This preserve specific part of the cell
CYTOLOGICAL
Type of cytological fixative that contains glacial acetic acid which preserves part of the nucleus
nuclear
Type of cytological fixative that do not contain glacial acetic acid and which preserves part of the cytoplasm
cytoplasmic
What is the pH of cytoplasmic fixative?
pH >4.6
What is the pH of nuclear fixative?
pH <4.6
Enumerate those under Nuclear fixatives
Flemming's with HAc Carnoy's Bouin's Newcomer's Heidenhain's susa
Enumerate those under Cytoplasmic fixatives
Flemmings without HAc Orth's Regaud's/Moller's Formalin with Post chroming Helly's
Enumerate those under Microanatomical fixatives
10% formol saline 10% neutral buffered formalin Heidenhain's susas Formol sublimate/formol corrosive Bouin's Zenker's Brasil's
Enumerate those under Histochemical fixatives
10% formol saline
Newcomer’s
Absolute ethyl alcohol
Acetone
Which of the following group of fixatives belong to Nuclear Fixatives:
A. 10% formol saline, 10% neutral buffered formalin, Heidenhain’s Susa, Formol sublimate/formol corrosive, Zenker’s, Bouin’s, Brasil’s
B. Flemming’s, Bouin’s, Carnoy’s , New comer’s Heidenhain’s Susa
C. Formol saline, absolute ethyl alcohol, acetone, new comers
D. Flemming’s regauds, Kelly’s fluid, formalin, regald, moller’s, orth’s
B
Satisfactory for routine paraffin sections for EM and other histochemical and enzyme studies
Aldehyde fixatives
Formaldehyde/Formalin may form what pigment color on blood-containing tissues like spleen?
Brown
Alcoholic formalin is also known as
Gendre’s solution
Enumerate all diluted forms of formalin
10% formol saline
10% neutral buffered formalin
Formol sublimate/corrosive
Alcoholic formalin
Percentage of commercially available formalin/formaldehyde
37-40%
What do you call the routine tissue fixative?
Formalin/formaldehyde
What is the penetration rate of formalin?
1 mm per hour
It is recommended for mailing specimens
Formalin/formaldehyde
Recommended for colloid tissue photography
formalin/formaldehyde
fumes are irritating, may cause allergic dermatitis on prolonged contact and may form brown
pigment on blood containing tissues like spleen
Formaldehyde/Formalin
What method contains Saturated alcoholic picric acid? A. Kardasewitsch method B. Picric acid Method C. 1% KOH in 80% alcohol D. Lillie’s Method
B
What method contains 70% ethanol 28% ammonia water? A. Kardasewitsch method B. Picric acid Method C. 1% KOH in 80% alcohol D. Lillie’s Method
A
What method contains Hydrogen peroxide 28% ammonia water and acetone? A. Kardasewitsch method B. Picric acid Method C. 1% KOH in 80% alcohol D. Lillie’s Method
D
precipitation of white paraformaldehyde is due to and can cause
prolonged storage and turbidity
remedy for precipitation of white paraformaldehyde
add 10% methanol
Formaldehyde is usually buffered to what pH
pH 7 with phosphate buffer
10% formol saline is diluted with
distilled water with sodium chloride
10% formol saline is used for
general post mortem tissues and for CNS tissue and general post
mortem tissues
10% Neutral Buffered Formalin or Phosphate Buffered formalin is used for
surgical post mortem and research specimens
for elastic fibers and for tissue with iron pigment
This is a combination of formaldehyde and mercuric chloride
Formol sublimate/corrosive
This is recommended for lipids, neutral fats and phospholipids
Formol sublimate/corrosive
This is used for sputum specimens and micro-incineration techniques
Alcohol formalin or Gendre’s solution
Karnovsky’s paraformaldehyde-glutaraldehyde solution and Acrolein are for
electron cytochemistry
This is recommended for enzyme histochemistry
Glutaraldehyde
What percentage of glutaraldehyde solution is used for small fragment of tissues
2.5%
What percentage of glutaraldehyde solution is used for larger tissues less than 4mm thick
4%
It is a fast-acting fixative and the smallest aldehyde fixative
Glyoxal
Glyoxal is supplied at what percentage of aqueous solution?
40%
When using glyoxal, surgical specimens are fixed within
4-6 hrs
When using glyoxal, small biopsy specimens are fixed within
45 mins
Penetrates poorly and produces shrinkage in tissue so it is
combine with other fixative.
Mercuric chloride
Mercuric chloride may form what color of deposits?
Black mercury deposits
Remedy for black mercury deposits
Alcohol iodine
What is the most common metallic fixatives and it preserves, _________
cell detail in tissue photography
Mercuric chloride is excellent for
Trichrome staining
Enumerate fixatives under mercuric chloride
Zenker’s fluid
Zenker’s formol
Heidenhain’s susa
B5
Zenker’s fluid contain
mercuric chloride and glacial acetic acid
Zenker’s fluid is used for fixing
liver, spleen, CT fibers and nuclei
Zenker’s formol is also known as
Helly’s fluid
Helly’s fluid contains
potassium dichromate and 40% formaldehyde
Zenker’s formol is used for
pituitary gland BM and blood containing organs like spleen and liver
Heidenhain’s Susa is used for
tumor-skin biopsies
B5 contains
anhydrous sodium acetate
B5 is used for
Bone marrow (BM)
Used for acid mucopolysaccharides and for tissue mucin A. Mercuric chloride B. Chromate fixatives C. Picric acid fixatives D. Lead fixatives
D
This type of fixative is used for CHO
Chromic acid
This type of fixative is used for rickettsia and other bacteria
Orth’s
Moller’s fluid is used for?
Chromatin, mitochondria, mitotic figures, Golgi body, RBC containing colloid tissues
Potassium dichromate preserves
lipids and mitochondria
Orth’s fluid is used for
early degenerative process and tissue necrosis
Removal of mercuric deposits is also known as what process
DEZENKERIZATION
Major drawback of using picric acid fixative
Imparts yellow color
Picric acid fixative is excellent for
glycogen demonstration
Picric acid fixative acts as:
Fixative, stain, and decalcifying agent
Remedy for yellow color left by using Picric acid fixative
Lithium carbonate and 70% alcohol
Bouin’s solution is excellent for preserving
embryos, pituitary biopsies and endometrial curettings.
Bouin’s solution should never be used for _____ and it also abolishes _____.
Kidneys and Fuelgen’s reaction
Hollande’s solution is good for
GIT biopsies and endocrine tissues
Brasil’s Alcoholic Picformol is excellent for
glycogen
Bouin’s solution is good for what stain?
Masson’s trichrome
Glacial acetic acid is what type of fixative?
Compound fixative
Glacial acetic acid is used in? At what pH?
Nuclear fixative at pH <4.6
Glacial acetic acid is recommended for ____.
Nucleoproteins
GLACIAL ACETIC ACID solidifies at what temperature?
17 degrees celcius
What is the disadvantage of using alcohol fixatives?
glycogen polarization
Alcohol fixatives is both ____ & ____.
Fixative & dehydrating agent
___ is used as a raw material in making _______
acetone, shabu
Alcohol fixatives will: A. Preserve enzymes B. Denatures rapidly and precipitates proteins C. Preserve nucleoproteins D. Stain with Masson's trichome
B
The MOST RAPID fixative
Carnoy’s fluid
It is used for CT mucins & umbilical cord. A. Lead fixatives B. Newcomer's C. 10% formalin D. Rossmann's
D
Ethyl alcohol is used for:
blood, tissue films and smears
Methyl alcohol is used for
wet and dry smears, blood smears and BM tissues
Touch preparation is under: A. Rossmann's B. Orth's C. Methyl Alcohol D. Isopropyl alcohol
D
Carnoy’s fluid is used for
chromosomes, lymph glands, brain tissue (RABIES)
Newcomer’s is used for
nuclear protein and mucopolysaccharides
Classified both as nuclear and histochemical fixative
Newcomer’s
Alcohol fixatives is ideal for
small tissue fragments
Rapid in action and may be used in urgent biospecimen A. Rossmann's B. Carnoy's C. Isopropyl alcohol D. Methyl alcohol
B
Expensive and not commonly used.
Osmium tetroxide
OSMIUM TETROXIDE is used for
peripheral tissues like myelin and peripheral nerves
Required volume for osmium tetroxide
5-10 times the volume of tissue
Disadvantage of using osmium tetroxide
conjunctivitis and blindness
2 types of osmium tetroxide
- Flemming’s w/ HAc
2. Flemming’s w/o HAc
WEAK DECALCIFYING AGENT
Trichloroacetic acid
A compound fixative with double purpose?
Trichloroacetic acid- fixative and decalcifying agent
Fixatives that can be used for fixing brain tissues in diagnosis for rabies
Acetone and Carnoy’s
Acetone
A. fixes and dehydrates
B. fixes and decalcify
C. fixes and stains
A
Acetone is used at what temperature
-5-4 degrees Celsius
Disadvantages of acetone
Dissolves fats and evaporates easily
It is used as raw material in making shabu
ACETONE
A type of fixation used in frozen sections
Heat fixation
It Involves thermal coagulation of CHON and in micro, it is used for bacterial smears
Heat fixation
It is done to improve demonstration of substance, ensure complete hardening and for special staining
Secondary fixation
A secondary fixation with the use of potassium dichromate
Post chromatization
Post chromatization is used for,
cytologic preservations
Removal of excess fixative from the tissue after fixation to improve staining and remove artifacts
washing out
Type of washing out technique used to remove excess amount of picric acid/bouin’s
50-70% alcohol
Type of washing out technique used to remove Kelly’s, zenker’s, flemming’s, Remove excess chromate, formalin, osmic acid
Tap water
Type of washing out technique used to remove excess mercuric fixative
alcoholic iodine
Type of washing out technique used to remove excess amount of picric acid/bouin’s
50-70% alcohol
These factors will retard fixation
size and thickness, presence of mucus, blood, fats, and cold temperature
These factors will accelerate fixation
smaller and thin tissues, agitation, heating 37-56 degrees Celsius
inactivation of enzymes is due to: A. prolonged fixation B. incomplete washing of fixative C. wrong choice of fixative D. incomplete fixation
C
presence of artefacts on tissues is due to: A. prolonged fixation B. incomplete washing of fixative C. wrong choice of fixative D. incomplete fixation
B
Tissue are soft and feather like in consistency are due to: A. prolonged fixation B. incomplete washing of fixative C. wrong choice of fixative D. incomplete fixation
D
shrinkage and swelling of cells is due to: A. overfixation B. incomplete washing of fixative C. wrong choice of fixative D. incomplete fixation
A
Microwave Technique may be used for neurochemical substances in brain like
acetylcholine
What is the secondary goal of fixation?
Harden tissues for easy cutting and protect from further trauma
It is a technique that increases movement of molecules thereby accelerating fixation, staining, decalcification, immunohistochemistry and EM
Microwave technique
Ideal time to perform fixation is
20-30 minutes following interruption of blood supply
This refers to the period the tissue is exposed to formalin
Fixation time
Volume of osmium tetroxide for EM;
5-10 time the volume of tissue
Volume of tissue for museum preparations
not <50-100 times the volume of specimen
Autopsy materials should be fixed as soon after death as
possible. If not possible, body must be placed in a mortuary
ref. What should be the temperature of mortuary ref?
4 degrees Celsius
Hollow organs (stomach, intestine) should be
put cotton soaked in with specimen or it is completely open
To prevent floating of air-filled lungs in fixative, what should be done?
cover with several layers of gauze to keep it at bottom
Human Brain must undergo
intravascular perfusion- washing out of blood using ringer’s lactate
Eyes should be dissected before they are fixed. True of False?
False
Hard tissues (cervix, uterine, fibroid etc.) must undergo what method?
Lendrum’s method- immersing in 4% aqueous phenol for 1-3 days
Factors to be considered when choosing the right fixative
- urgency
- tissue structure
- type of stain
- type of specimen
This type of additive stabilizes tissue proteins
A. Non-additive
B. Additive
B
This type of additive involves alteration of tissue components
A. Non-additive
B. Additive
A
Examples of non-additive fixatives are:
Alcohol and acetone
Recommended for mailing specimens and colloid tissue photography A. formalin/formaldehyde B. Mercuric chloride C. Glutaraldehyde D. Picric Acid fixative
A
Disadvantages of using formalin/formaldehyde
- irritating fumes
- contact dermatitis
- brown pigment on blood-containing tissue like spleen
It is used for fixing liver, spleen, CT fibers and nuclei A. Zenker's formol/Helly's B. Zenker's fluid C. B5 D. Heidenhain's susa
B
Zenker's fluid contains A. anhydrous sodium acetate B. Potassium dichromate and 40% formaldehyde C. Mercuric chloride and HAc D. TCA, Glac HAc & formalin
C
It is used for lipids, neutral fats and phospholipids A. Zenker's fluid B. B5 C. 10% Neutral buffered formalin D. Formol sublimate/corrosive
D
It is used for pituitary glands, BM and other blood-containing tissues A. Heidenhain's susa B. Zenker's Fluid C. Helly's fluid D. Alcoholic iodine
C
It is used for tumor skin biopsies A. Heidenhain's susa B. Formol sublimate C. Zenker's fluid D. Potassium dichromate
A
It is used for acid mucopolysaccharides and tissue mucin A. Potassium dichromate B. B5 C. Lead fixatives D. Glutaraldehyde
C
It is used for chromatin, mitochondria, mitotic figures, golgi bodies and RBC containing colloid tissues. A. Regaud's/Moller's B. Helly's C. Gendre's D. Alcoholic iodine
A
It is used for early degenerative processes and tissue necrosis. A. Moller's B. Helly's C. Orth's D. Zenker's
C
Fixatives used for enzyme histochemistry
4% formaldehyde
Formol saline
Fixatives used for EM and Electron histochemistry
Glutaraldehyde
Osmium tetroxide
Paraformaldehyde
Which of the following will remove picric acid/bouin’s?
A. Alcohol iodine
B. 50-70% alcohol
C. Tapwater
B
Which of the following will remove excess mercuric chloride?
A. Alcohol iodine
B. 50-70% alcohol
C. Tapwater
A
Which of the following will remove zenker’s?
A. Alcohol iodine
B. 50-70% alcohol
C. Tapwater
C
adequate fixation time (book)
4-6 hrs
recommended size of the tissue (book)
2 cm2, and no more than 4 mm. thick.
rate of penetration for aldehyde fixative (book)
two to-three millimeter per hour
For solid material (e.g., liver) the longest dimension should not exceed (book)
10-15mm
commonly added to osmium tetroxide fixatives for electron
microscopy (book)
sucrose
Formaldehyde is normally used at what percent of solution? (book)
10%
Glutaraldehyde is normally used at what percent of solution? (book)
3%
It destroys mitochondria and Golgi bodies of the cytoplasm. (book)
glacial acetic acid
Small endoscopic specimens are particularly susceptible to this type of damage. (book)
Drying of specimen
Purulent material, exudates or transudates should be marked and kept for possible cultures, smears and other bacteriologic examination. True or false? (book)
true
Human brains may be suspended by a (book)
cord tied under the Circle of Willis to prevent flattening
Intravascular perfusion (washing out of blood with Ringer’s lactate) may lead to? (book)
artifact formation with loss of blood content
Frozen sections may lead to formation of (book)
ice crystal artifacts
prepared from stock solutions immediately before use because they are unstable (book)
Helly’s fluid
a well-known artifact that may be produced under acid
conditions. (book)
formalin pigment
Failure to arrest early autolysis of cells (book)
Failure to fix immediately, Insufficient fixative
Formalin pigment may be eliminated or reduced by (book)
fixation in phenol formalin
may be found in surgical specimens particularly in liver
biopsies, associated with an intense eosinophilic staining at the center of the tissue in H&E stained sections. (book)
Crush artifact
should be used for demonstrating lipid in tissues, followed by a general lipid stain. (book)
Cryostat or frozen sections
The most useful fixatives for preserving glycogen (book)
Rossman’s fluid or cold absolute alcohol
commonly used fixatives for amino acid histochemistry (book)
Neutral buffered formal saline or formaldehyde vapor
commonly used in pathology for the demonstration of various antibodies (book)
Immunofluorescence techniques
Examples of organic solvents
alcohols and acetone
Example of Cross-linking reagents
paraformaldehyde
causes covalent cross-links between molecules, effectively gluing them together into an insoluble meshwork (book)
paraformaldehyde
variables that need to be considered when developing immunohistochemistry protocols (book)
Fixation method, time, and temperature
immunofluorescent (IF) staining is best done on (book)
frozen sections
Background auto fluorescence, to a greater or lesser degree, can be
suppressed by a post-staining (book)
Sudan Black treatment
Microwave antigen retrieval is one of several so-called what method
‘HIER’ (heat induced epitope retrieval) methods
considered to be the major factor responsible for the effects of
microwaves during tissue fixation. (book)
heat
After microwaving they should immediately be sliced to
_____ and placed in ______. (book)
2 mm, 70% ethanol
The chief advantage of microwave fixation (book)
tissue is heated right through the block in a very short time, thereby potentially allowing the study of cellular processes that proceed very rapidly.
microwave fixation is useful in preserving (book)
neurochemical substances in brain, such acetylcholine
Two types of chemical fixatives according to their mechanism of action
Crosslinking Fixatives (e.g., Aldehydes) and Precipitating (or denaturing) fixatives (e.g., alcoholic fixatives)
presence of buffer prevents
formalin pigmentation
can be used as a fixative for cell smears
formaldehyde vapor
what is the ratio in diluting the concentrated formalin in phosphate buffer?
1:10
“Overnight” fixation (i.e., 8-12 hours) is generally indicated for
10 mm thick slices of tissues
At what temperature does native DNA and RNA do not react with formaldehyde?
20-22 degrees Celsius
At what temperature does RNA and DNA consecutively reacts?
45 and 65 degrees Celcius
recommended for colored tissue photography
formalin
Formation of brown pigment granules on blood-containing tissues, e.g., spleen is due to:
blackening of hemoglobin
If there is a necessary delay in fixation, the tissue should be immersed in: A. Formalin/formaldehyde B. Cold phosphate-buffered saline (PBS) C. Formol sublimate D. Zenker's
B
Natural tissue colors may be restored by immersing tissues in \_\_\_\_\_\_\_ after fixation. A. 10% methanol B. 70% alcohol C. Lithium carbonate D. Glacial acetic acid
B
Brown or black crystalline precipitate formed by the action of formic acid with blood and can be removed from the sections prior to staining by
treatment with?
saturated alcoholic picric acid or a 1% solution of potassium hydroxide in 80% alcohol
If fatty tissues are to be stored for a long time, what can be added to prevent dispersion of fat out into the fluid.
cadmium or cobalt salts
post-fixed in osmic acid may result in hypotonicity and bleaching, to prevent this, what should be done:
A. must not be washed in demineralized water
B. fix in 70% ethyl alcohol
C. wash with tap water
D. wash with 50-70% alcohol
A
Fixation of tissue blocks not exceeding 5 mm. in thickness is usually
complete in ______ hours at room temperature.
A. 6-12
B. 4-6
C. 24
D. 24-48
A
Fixation time of 10% Formal-Saline
12 – 24 hours
pH of 10% Formal-Saline
pH of 6.8
Paraformaldehyde is suitable for:
A. lipids, neutral fats and phospholipids
B. paraffin embedding, sectioning and immunocytochemical analysis
C. general post mortem tissues
D. iron pigmented tissues and elastic fibers
B
The most efficient aldehyde blockers are
ethanolamine and lysine
Solid specimens taken from patients with gout are usually fixed in
95% ethanol
appears to give the most usable
DNA fragments for polymerase chain reaction (PCR)
Ethanol
The color of the specimen can be preserved for photographic work using A. 70% alcohol B. 80% alcohol C. 90% alcohol D. 100% alcohol
B
Isopropyl Alcohol 95% is used for certain special staining procedures such as
Wright-Giemsa
What happens when lower concentrations (lower than 70-100%) of ethyl alcohol are used?
A. cell shrinkage
B. cell swelling
C. RBC’s become hemolyzed and WBC’s are inadequately preserved.
D. precipitation of proteins
C
fixation time of ethyl alcohol
18-24 hours
Carnoy’s Fixative fixation time
1-3 hours
Clarke’s solution has been used on
frozen sections and smears
It preserves nucleic acids but extracts lipids. A. Helly's B. Zenker's C. Clarke's D. Bouin's
C
Alcoholic formalin fixation time
12-24 hours
It can be used for fixation or post-fixation of large fatty specimens (particularly BREAST) A. Alcoholic formalin B. Zenker's fluid C. Helly's D. Acetone
A
Formol-acetic alcohol fixation time
1-6 hours
Newcomer’s Fluid fixation time
12-18 hours at 3°C
It produces better reaction in Feulgen stain than Carnoy's fluid. A. Regaud's/Moller's B. Newcomer's C. Rossmann's D. Clarke's
B
It is recommended for renal tissue, fibrin, connective tissue and muscle. A. mercuric chloride B. lead fixatives C. potassium dichromate D. B5
A
Zenker’s Solution fixation time
12-24 hours
Trichome staining
Zenker’s solution
It is recommended for congested specimens (such as lung, heart and
blood vessels) and gives good results with PTAH.
A. Zenker’s fluid
B. Potassium dichromated
C. Helly’s
D. Newcomer’s
A
Zenker-Formol (Helly’s) Solution fixation time
4 – 24 hours
This mixture enhances nuclear detail, which is important for identifying normal and abnormal cell types in bone marrow (hematopoietic tissue) specimens. A. Helly's B. Rossmann's C. B5 D. Lillie’s B-5 Fixative
D
Lillie’s B-5 Fixative fixation time
4-8 hours
Heidenhain’s Susa Solution fixation time
3-12 hours
This method of staining elastic fibers is not possible in Susa fixed tissues. A. Romanowsky's B. Giemsa's C. Wright's D. Weigert's
D
traditionally used in electron microscopy both as a fixative and a heavy metal stain. A. Potassium dichromate B. Glacial acetic acid C. Chromic acid D. Osmium tetroxide
D
the most common chrome-osmium acetic acid fixative used
flemming’s solution
It permanently fixes fat. A. Osmium tetroxide B. Flemming's solution C. Chromic acid D. Zenker's fluid
B
Flemming’s solution’s fixation time
24-48 hours
It is a strong oxidizing agent A. Osmium tetroxide B. Flemming's solution C. Chromic acid D. Zenker's fluid
C
Orth’s Fluid Fixation time
36-72 hours
an explosive hazard in dry form A. Bouin's B. Glacial Acetic acid C. Picric Acid D. Osmium tetroxide
C
Prolonged storage in this acidic mixture causes hydrolysis and loss of stainable DNA and RNA. A. Bouin's B. Glacial Acetic acid C. Picric Acid D. Osmium tetroxide
A
Bouin’s solution fixation time
4 – 18 hours
It is suitable for Aniline stains (Mallory's, Heidenhain's or Masson's methods). A. Picric Acid B. Glacial Acetic acid C. Bouin's D. Osmium tetroxide
C
It is the preferred fixative for tissues to be stained by Masson’s
trichrome for collagen, elastic or connective tissue.
A. Picric Acid
B. Gendre’s solution
C. Bouin’s
D. Osmium tetroxide
B
a reagent that is used for the precipitation of proteins and nucleic acids. A. Picric Acid B. Glacial Acetic acid C. TCA D. Osmium tetroxide
C
provides a stable medium for transport of fresh unfixed
tissues, such as renal, skin and oral mucosa biopsies.
A. Picric Acid
B. Glacial Acetic acid
C. TCA
D. Michel’s solution
D
Cryostat or frozen sections should be used in what tissues?
Lipids
Most usable for DNA fragments for PCR A. bouin's B. Formaldehyde C. ethanol D. Zenker's fluid
C
Traditionally the amount of fixative use is A. 10x the vol. of specimen B. 20-30x the vol. of the specimen C. 10-25 vol. of the specimen D. 5x vol. of the specimen
C
normally used in strong saturated aqueous solution (approximately 1%)
Picric acid
It is a form of secondary fixation where in the already fixed tissue is placed in 2.5-3% pot. dichromate
post chromatization
Aldehyde fixative recommended for preservation and storage of surgical specimen A. Phosphate buffered formalin B. Glutaraldehyde C. Alcohol formalin D. Formol corrosive
A
One of the advantage of this fixative is it fixed myelin and peripheral nerve as well
Osmium tetroxide
It is an excellent microanatomic fixative for pituitary gland, bone marrow, and blood containing organs A. Helly's soln B. Brasil's fluid C. Moller's fluid D. Orth's fluid
A
Low temperature retards fixation but prevent autolysis
True or false
True
This method of fixation involves thermal coagulation of protein and usually employed in frozen tissue section
Heat fixation
Alcohol formalin is also known as A. Moller's fluid B. Helley's fluid C. Gendre's fixative D. Formol sublimate
C
Tissue should not be more than 5mm thick except in lung edema
True or false
true
Hard specimen must be immersed overnight with 4% aqueous sol’n
True or false
false, dpat 1-3 days
Chromic acid and osmic acid is the component of flemming’s soln without acetic acid
True of false
True
Alcoholic fixative suitable for small tissue fragments such as currettings and biopsy material A. Carnoy's fluid B. Isopropyl acohol 95% C. Newcomer's fluid D. Ethyl alcohol
A
Water is used to remove picric acid fixative
True or false
False
Eyes as a specimen should not be dissected prior to fixation
True or false
True
Over fixation will result to shrinkage and swelling of cells and tissue structure
True of false
True
Specific fixative recommended/utilize to fix nuclear structure A. Heidenhain's susa B. B5 fixative C. Zenker's formol D. Flemming's solution
D
Human brains shall be washed out with Ringer’s lactate sol’n
True or False
True
This type of fixative does not need washing out process after fixation
A. Bouin’s sol’n’s
B. Bouin’s solution
B
Wrong choice of fixative will result to removal of substances in the cells or structure
True of false
True
Metallic fixative for preservation of cell detail in tissue photography A. mercuric chloride B. heidenhain's susa C. Zenker''s sol'n D. B5 fixative
A
Specific fixative for fixing brain tissue for rapid diagnosis of rabies
Acetone
