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HISTOPATH LEC - UNIT 4 NEOPLASIA > FIXATIVES > Flashcards

FIXATIVES Flashcards

1
Q

For Routine Paraffin Sections, Electron Microscopy,
Histochemistry & Enzyme Studies

A

10% FORMALIN

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2
Q

Most effective fixative.

A

10% FORMALIN

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3
Q

Cheap, Readily Available, Easy to Prepare.
● Relatively Stable.
● Compatible with many stains.
● Fumes irritating to nose and eyes.

A

10% FORMALIN

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4
Q

10% NaCl (sodium chloride) Solution as diluent.
● Fixation of Central Nervous Tissues.
● Post-Mortem Tissues for Histochemical Examinations.
● Fixation time : 24 hrs.(35 degrees) / 48 hrs. (room
temperature).

A

10% FORMOL SALINE

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5
Q

Preservation and Storage of Surgical, Post-Mortem
and Research Specimens.

4 TO 24 HRS

A

10% NEUTRAL BUFFERED

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6
Q
  1. Fast penetration.
  2. Non-coagulant and additive.
  3. Prevents alterations during processing.
  4. Less shrinkage than other fixatives.
  5. Not osmotically active.
  6. Hardens tissue better (except alcohol and acetone)
A

10% NEUTRAL BUFFERED

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7
Q

Mercuric Chloride as diluent.

A

FORMOL CORROSIVE

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8
Q

Recommended for Routine Post-Mortem Tissues.

Brightens Cytoplasmic and Metachromatic Stains.

Slow penetration.

A

FORMOL CORROSIVE

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9
Q

polymerized form of formaldehyde, usually
obtained as a fine white powder, which depolymerizes
back to formalin when heated.

A

PARAFORMALDEHYDE

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10
Q

It is suitable for paraffin embedding and sectioning,
and also for immunocytochemical analysis.

fixed samples can also be stained
for general histology but the degree of fixation is less vigorous than Bouin’s so the quality of the morphology obtained will be less

A

PARAFORMALDEHYDE

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11
Q

mixture of paraformaldehyde and glutaraldehyde.
● It is suitable for use when preparing samples for light microscopy in resin embedding and sectioning, andfor electron microscop

A

KARNOVSKY FIXATIVE

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12
Q

This fixative should always be prepared fresh.

A

KARNOVSKY FIXATIVE

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13
Q

For Routine Light Microscopy, also for Electron Microscopy.

● Preserves cellular structures better.

● Less Irritating to nose and skin.

A

GLUTARALDEHYDE

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14
Q

small tissue fragments and needle
aspirates.

A

2.5% SOLUTION

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15
Q

glutaraldehyde larger tissues

A

4% SOLUTION

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16
Q

Nuclear components are shown in fine detail.
● Excellent Trichrome Staining.
● Preservation of cell detail in Tissue Photography.

A

MERCURIC CHLORIDE

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17
Q

Pigments removed by treatment with

A

85-95% Alcoholic Iodine

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18
Q

Permits brilliant staining of nuclear and connective
tissue fibers.
● For Liver, Spleen, Connective Tissue Fibers, and
Nuclei
● Fixation time: 12-24 hrs.
● Lyses RBC and can make tissues brittle.

A

ZENKERS FLUID

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19
Q

For Pituitary Gland, Bone Marrow and Blood
Containing Organ (e.g. Spleen and Liver).

A

ZENKERS FORMOL (HELLY’s SOLN)

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20
Q

● Preserves Cytoplasmic Granules

A

ZENKER-FORMOL (HELLY’s SOLN)

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21
Q

Tumor biopsies of skin.
● Excellent Cytologic Fixative.
● Fixation time: 3-12 hrs.
● Penetrates and fixes tissue rapidly and evenly.

A

HEIDENHAIN’s SUSA

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22
Q

BONE MARROW BIOSPSIS

A

B-5 FIXATIVE

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23
Q

Fixation time: 4 – 8 hours

● RAPID FIXATION: 1 1/2-2 hrs
● Unstable.
● Can make tissues brittle.
● Good clear nuclear details.

A

B-5 FIXATIVE

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24
Q

Preserves Carbohydrates and precipitates all proteins.
May produce sub oxide precipitates.
USUALLY CONSTITUENT OF COMPOUND FIXATIVE

A

1-2% CHROMIC ACID

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25
Q

LIPIDS AND MITOCHONDRIA

A

3% POTASSIUM DICHROMATE

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26
Q

Recommended for demonstration of Chromaffin
tissues (phaeochromocytoma), Mitochondria, Mitotic Figures, Golgi Bodies, RBC, and Colloid-containing
tissues(Adrenal glands)

FIXATION TIME: 12-48
PENETRATES WELL

A

REGAUDS FLUID (MULLER)

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27
Q

Fixation time: 36-72 hours

Recommended for study of Early Degenerative
Processes and Tissue Necrosis

A

ORTHS FLUID

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28
Q

Recommended for Acid Mucopolysaccharides.

Mucopolysaccharides could be an inborn
error of metabolism.

Fixes connective tissue mucin.

A

LEAD FIXATIVES

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29
Q

small tissue rapidly.

Excellent for Glycogen Demonstration.

● Suitable for Aniline Stains.
● Causes RBC hemolysis.

A

1% PICIRC ACID SOLN

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30
Q

Not suitable for frozen sections– causes it to
crumble when cu

A

1% PICRIC ACID SOLN

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31
Q

recommended for fixation of
embryos and pituitary biopsies.

Preferred fixative for connective tissue staining.

Minimal distortion of
microanatomical structures.

A

BOUIN SOLN

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32
Q

Minimal distortion of microanatomical structures.

Excellent for soft and delicate tissues.

A

BOUIN SOLN

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33
Q

Fixation time: 4 – 18 hours

Recommended for gastro-intestinal tract specimens
and fixation of endocrine tissues

A

HOLLANDES SOLN

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34
Q

Less messy than Bouin’s solution.

Excellent for Glycogen staining.

A

BRASILS ALCOHOLIC PICRO FORMOL

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35
Q

Overnight tissue fixation by automatic processing
technique may utilize 3-4 changes of Brasil’s fixative
at 1/2 to 2 hours each, succeeded directly by absolute
alcohol.

A

BRASIL’S ALCOHOLIC PICRO FORMOL FIXATIVE

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36
Q

Rapidly denatures and precipitates proteins
by destroying hydrogen bonds to stabilize
the tertiary structure of proteins.

A

ALCOHOL FIXATIVES

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37
Q

Recommended for fixing dry and wet smears, blood
smears and bone marrow tissues.

A

100% METHANOL

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38
Q

Preserves Nucleoproteins and Nucleic Acids for
Histochemistry and Enzyme studies.

Dissolves fat and lipids.

A

70-100% ETHANOL

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39
Q

May be used as a simple fixative.

Fixes blood, tissue films and smears.

May shrink tissue

A

70-100% ETHANOL

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40
Q

The most rapid fixative(1-3 hrs only).
● Fixes and dehydrates at the same time.
● Used to fix the brain (fragile specimen)

RBC LYSIS

A

CARNOYS FLUID

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41
Q

Fixation time: 3-4 hours

has been used on frozen sections
and smears.

A

CLARKES SOLN

42
Q

Fixation time: 1 - 6 hours
● Recommended Applications.
● It is sometimes used to fix diagnostic cryostat
sections.

A

FORMOL ACETIC ALCOHOL

43
Q

Post-fixation with phenol-formalin
for 6 hours or more can enhance immunoperoxidase
studies.

A

ALCOHOL FORMALIN

44
Q

Useful for Sputum analysis as it
coagulates mucus.

A

GENDRES FLUID

45
Q

Isopropanol, Propionic Acid, Petroleum Ether, Acetone, Dioxane.

● Acts both as Nuclear and Histochemical Fixative.

● Produces better reaction in Feulgen stain

A

NEWCOMERS FLUID

46
Q

Recommended for fixing mucopolysaccharides.
● Fixation time: 12-18 hours at 3°C.

A

NEWCOMERS FLUID

47
Q

can react with various side
chains of proteins and other biomolecules, allowing
formation of crosslinks that stabilize tissue structure
but cause extensive denaturation despite preserving
fine cell structure and are used mainly as secondary
fixative.

A

OXIDIZING AGENTS

48
Q

Fixes conjugated fats and lipids permanently by
making them insoluble to alcohol and xylene during
dehydration and clearing

A

6% OSMIUM TETROXIDE

49
Q

Main Purpose: Fixes materials for Ultrathin Sectioning in Electron Microscopy.

● Drawback: Very Expensive.
● Penetrates poorly.
● Forms black precipitates upon exposure to sunlight.

A

6% osmium tetroxide

50
Q

With 1% Chromic Acid as diluent.
● Fixation time: 24-48 hrs
● Recommended for nuclear preparation of such
sections.
● Permanently fixes fat.
● Excellent fixative for nuclear structures

A

FLEMMING SOLN

51
Q

Recommended for cytoplasmic structures particularly the Mitochondria

A

FLEMMING SOLN WITHOUT GLACIAL ACETIC ACID

52
Q

Sometimes incorporated into compound fixatives.
● It precipitates proteins.
● Softening effect on dense fibrous tissues.
● May be used as a weak decalcifying agent.
● Poor penetration.

A

TRICHLOROACETIC ACID

53
Q

Used at ice cold temperature (-5 to 4 °C).
● Recommended for the study of water diffusible
enzymes i.e. Phosphatases and Lipases.
● Used in Fixing Brain Tissues for diagnosis of Rabies.
● Volatile.
● Dissolves fat.

A

ACETONE

54
Q

Stable medium for transport of fresh unfixed tissues,
such as renal, skin and oral mucosa biopsies, which
will undergo subsequent frozen section and
immunofluorescence studies.

A

MICHELS SOLN

55
Q

Involves Thermal Coagulation of tissue
protein.
■ For Rapid diagnosis;
■ Employed for Frozen Tissue
Sections and Bacteriologic Smears
(gram stain).

A

HEAT FIXATION

56
Q

well-known artifact that may be
produced under acid conditions. The pigment may be
eliminated or reduced by fixation in phenol - formalin.

A

FORMALIN PIGMENT

57
Q

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.

A

CRUSH ARTIFACT

58
Q

due to partial coagulation of
partially fixed protein by ethanol or by
incomplete wax impregnation during
subsequent histological processing.

A

CRUSH ARTIFACT

59
Q

7 . Tissue can be stored in formalin indefinitely (except for
IHC).
8. Fixative of choice for Immunohistochemistry and
molecular tests.
9. Cheap and stable.

A

10% NEUTRAL BUFFERED

60
Q

Chemical constituent
taken into the cell,
forming molecular
complexes and
stabilizing proteins.

A

Additive
Non coagulant

61
Q

Chemical constituent
taken into the cell,
forming molecular
complexes and
stabilizing proteins.

A

Additive
Non coagulant

62
Q

Fixing agent is not
incorporated into the
tissue

Dehydrating coagulant fixative

Alteration of tissue composition

A

Non additive
Coagulant

63
Q

Prevents autolysis and inactivated infectious agents

Allows sectioning of tissue by hardening tissues

Improves cell acidity for special stains

Functions as mordants/accentuators

A

BENEFITS OF STAINING

64
Q

Satisfactory fixation occurs between pH

A

pH 6 and 8

65
Q

increasing the temperature, increases
the rate of diffusion into the tissue and speed up the rate of chemical reaction between the fixative and tissue elements.

A

TRUE

66
Q

Fixation of surgical specimens are done at room

A

22-25

67
Q

Temp for electron microscopy

A

0-4

68
Q

Nucleic acids do not react with fixatives at room
temperature

A

TRUE

69
Q

THICKNESS OF THE SECTION FOR EM

A

1-2 mm

70
Q

THICKNESS OF SECTION FOR LM

A

2 cm

71
Q

Brain is usually suspended whole in 10% buffered
formalin for 2-3 weeks

A

TRUE

72
Q

Tissue thickness is important especially with
non-coagulant fixatives

A

TRUE

73
Q

Large specimens like colon resections should be
opened or sectioned at small intervals prior to fixation.

A

TRUE AT 3-4 mm

74
Q

The best result is usually obtained using slightly
hypertonic solutions(400-450 mOsm).

A

TRUE

75
Q

0.25% Glutaraldehyde - for immunoelectrochemistry

A

TRUE

76
Q

Prolonged fixation may cause shrinkage and
hardening of the tissue and may severely inhibit
enzyme activity and immunological reaction.

A

TRUE

77
Q

Ideal time to perform fixation is ____
minutes after the interruption of blood
supply.

A

20-30 minutes

78
Q

Tissue must be immersed in the fixative for
no longer than ______

A

60 minutes

79
Q

Interval between the interruption of blood
supply and the time the tissue is immersed in
the fixative.

A

cold ischemia time

80
Q

Time period the tissue is exposed to formalin
or fixative.

A

fixation time

81
Q

A commonly quoted rate of penetration for aldehyde fixative is ______ per hour and slows down as it goes deeper in the tissue

A

2-3mm

82
Q

_____ times the volume of the tissue to be fixed.

A

10-25 times

83
Q

_____ times the volume of the tissue to be fixed.

A

10-25 times

84
Q

_____ times the volume of the tissue to be fixed.

A

10-25 times

85
Q

tissues should be fixed in a
sufficient volume of solution; generally in a
ratio of 20:1 or at least 10:1 fixative to
specimen.

A

TRUE

86
Q

tissues should be fixed in a
sufficient volume of solution; generally in a
ratio of 20:1 or at least 10:1 fixative to
specimen.

A

TRUE

87
Q

The maximum effectiveness of fixation is
noted to be 20 times the tissue volume
(1:20).

FIXATIVE:TISSUE VOLUME

A

TRUE

88
Q

Fibrous organs take longer than small or loosely
textured tissues such as biopsies or scrapings

A

TRUE

89
Q

Fixation can be cut down by using heat, vacuum,
agitation, or microwave.

A

TRUE

90
Q

The pH of fixatives does not affect light microscopy.

A

TRUE

91
Q

Formalin which is not buffered, is acidic, and has low
pH (pH 4) has little effect on the fine structure of cells

A

TRUE

92
Q

At low pH, formalin produces a _____ which
can obscure cellular detail.

A

DARK PIGMENT

93
Q

It is necessary to buffer formalin at ______ to prevent
this occurrence

A

pH 7

94
Q

The tissue selected for sectioning should be thin
enough to allow penetration by fixative within a
reasonable amount of time.

A

TRUE

95
Q

To maintain an adequate fixation time of _____
the tissue size must be _____

A

fixation time: 4-6 hours
tissue size: 2cm

96
Q

is used to slow down decomposition if
the tissue that needs to be photographed cannot be
fixed immediately.

A

REFRIGERATION

97
Q

is used to slow down decomposition if
the tissue that needs to be photographed cannot be
fixed immediately.

A

REFRIGERATION

98
Q

alcohols and acetone
remove lipids and dehydrate the cells, while
precipitating the proteins on the cellular architecture.

A

Organic solvents

99
Q

alcohols and acetone
remove lipids and dehydrate the cells, while
precipitating the proteins on the cellular architecture.

A

Organic solvents

100
Q

form intermolecular bridges, normally through free
amino groups, thus creating a network of linked
antigens.

A

cross linking reagents
(paraformaldehyde)

101
Q

Cross-linkers preserve cell structure better than
organic solvents, but may reduce the antigenicity of
some cell components, and require the addition of a
permeabilization step, to allow access of the antibody
to the specimen.

A

CROSS LINKERS BETTER THAN ORGANIC

102
Q

may be used
to preserve phospholipids.

A

BAKERS FORMAL CALCIUM

HISTOPATH LEC - UNIT 4 NEOPLASIA (2 decks)

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