FIXATIVES Flashcards

1
Q

for routine paraffin sections, em, histochemical and enzymes

A

Aldehyde Fixatives

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2
Q

commonly used Aldehyde

A

10% Formalin

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3
Q

Fixation time of Aldehyde Fixatives

A

24 hours

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4
Q

Advantage of Aldehyde Fixative

A

cheap, readily available, easy to prepare, stable especially if stored in buffered solutions

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5
Q

Compatible w/ many stains
Does not overharden tissues
Penetrates tissues well
Preserve fat and mucin
Preserves glycogen
Does not precipitate proteins, for nervous tissue
For frozen tissue, does nor require washing out
Tolerant fixative

A

Advantage of Formaldehyde

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6
Q

Irritating fumes
Shrinkage of tissue
Soft fixative-does not harden some cytoplasmic structures
If unbuffered: reduces basophilic and eosinophilic stains; produce brown pigment granules on bld-contng tissue( spleen)
Prolonged: bleaching, fat dispersal, glycogen and biurate of sodium crystals dissolution

A

Disadvantage of Formaldehyde

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7
Q

Made up of saturated formaldehyde (40% by weight volume) diluted to 10% with NaCl

A

10% Formol-Saline

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8
Q

10% Formol-Saline is used for..

A

For CNS and general post mortem tis for histochemical exams

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9
Q

Fixation time of 10% Formol-Saline

A

Fixation time:

24 hrs at 35oC (95oF)
48 hrs at 20-25oC (65-77oF)

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10
Q

Preserves enzymes and nucleopoteins
Demonstrates fats and mucin

A

advantage of 10% Formol-Saline

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11
Q

Disadvantages are similar to formaldehyde with the ff addition:

It is slow fixative
Metachromatic reaction of amyloid is reduced
Acid dye stains less brightly than when fixed with Mercuric chloride

A

disavantage of 10% Formol-Saline

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12
Q

used for preservation and storage of surgical, post mortem and research specimens

A

10% Neutral Buffered Formalin or Phosphate-Buffered Formalin (pH 7)

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13
Q

Prevent pption of acid pigments on post mortem tissue and Best fixative for Iron pigments and elastic fibers

A

advantages of 10% Neutral Buffered Formalin or Phosphate-Buffered Formalin (pH 7)

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14
Q

fixation time of 10% Neutral Buffered Formalin or Phosphate-Buffered Formalin (pH 7)

A

4 to 24 hours

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15
Q

Time consuming
Positivity of mucin to PAS is reduced
Raecativty to Weigert’s Fe hematoxylin stain is reduced
Inert to lipids

A

disadvantage of 10% Neutral Buffered Formalin or Phosphate-Buffered Formalin (pH 7)

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16
Q

used For routine post mortem tissues

A

Formol-Corrosive (formol-sublimate)

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17
Q

Formol-Corrosive (formol-sublimate) fixation time

A

3 to 24 hours

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18
Q

Excelelnt for silver reticulin
Cytologic structures and blood cells are well preserved
NO need for washing out, tissues can be directly transferred to alcohol
Fixes lipids, neutral fats and phospholipids

A

advantage of Formol-Corrosive (formol-sublimate)

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19
Q

Penetration is slow, (not more than 1 cm)
Forms Mercuric chloride deposits
Does not allow frozen tissue sections
Inhibits tissue decalcification

A

disadvantage of Formol-Corrosive (formol-sublimate)

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20
Q

In alcoholic formalin, the post-fixation with …

A

Post fixation with phenol-formalin for 6 hrs or more can enhance immunoperoxidase studies on the tissues

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21
Q

Fixation is faster
Fixes and dehydrates
Preserves glycogen and for micro-incineration technique
Fix sputum

A

advantage of alcoholic formalin

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22
Q

Cause partial Lysis of RBC

A

disadvantage of alcoholic formalin

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23
Q

used For enzyme histochem and EM

A

Glutaraldehyde

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24
Q

fixation time in glutaraldehyde

A

2.5% (small tissue fragments)-2-4 hrs
4% Large- 6-8 to 24 hrs (4mm)

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25
Q

More pleasant and less irritating to the nose
Specimen vial should be refrigerated
Does not cause dermatitis
More expensive, less stable

A

Glutaraldehyde.

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26
Q

5-7% included in compound fixatives
Penetrates and hardens tissue rapidly
Routine fixative of choice in Tx photography

A

Metallic Fixatives

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27
Q

common metallic fixative

A

Mercuric Chloride

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28
Q

Metallic fixatives May produce black granular deposits except

A

Heidenhens susa

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29
Q

in metallic fixatives, Removal can be done by addition of ____

A

saturated iodine solution of 96% Alcohol

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30
Q

fluids/solutions under mercuric chloride

A

Zenker’s
Zenker-Formol
Heidenhain’s Susa
B5 Fixative

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31
Q

Contains Glacial Acetic acid
For small pieces of liver, spleen, CT fibers and Nuclei
Recommended for trichrome staining

A

Zenker

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32
Q

Dezenkeration is removal of ___ deposits using ____ and _____

A

Mercury ; Lugol’s Iodine and Na Thiosulfate

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33
Q

Zenker-Formol composition

A

Potassium Dichromate and Formalin

34
Q

Zenker-Formol is used for

A

For pituitary gland, BM and Bld containing Organs

35
Q

Zenker Formol preserves

A

Preserves cytoplasmic granules

36
Q

Zenker-formol produce brown pigments which can be removed

A

remove using picric acid or NaOH

37
Q

Has TCA, Glacial acetic acid and Formaldehyde

A

Heidenhain’s Susa

38
Q

Heidenhain’s Susa is used for

A

For skin tumor biopsies

39
Q

Heidenhain’s Susa is excellent ___

A

cytologic ficative

40
Q

in Heidenhain’s Susa, the RBC preservation is ___

A

poor

41
Q

has Anhydrous Na acetate and used for bone marrow biopsies

A

B5 Fixative

42
Q

Time in B5 Fixative

A

1/2

43
Q

the chromate fixatives

A

Chromic Acid
Potassium Dichromate

44
Q

1-2% aqueous solution Strong oxidizing agents

A

Chromic Acid

45
Q

Chromic Acid preserves

A

Preserves CHONs and CHO

46
Q

in chromic acid, a ___ must be added before used in order to prevent _____ of solution on prolonged standing

A

Strong reducing agent must be added before use in order to prevent counteracting effects and decomposition of solution on prolonged standing

47
Q

used in a 3% aqueous solution and it Fixes but does not ppt cytoplasmic structures

A

Potassium Dichromate

48
Q

K Dichromate preserves

A

Preserves lipids, mitochondria (pH 4.5-5.2)

49
Q

if K dichromate is acidified:

A

fixes cytoplasm, chromatin bodies and chromosomes

50
Q

2 fluids under potassium dichromate

A

Regard’s (Muller)
Orth

51
Q

For chromatin, mitochondria, mitotic figure, Golgi apparatus, RBC and colloid-containing tissues

A

Regard’s (Muller’s Fluid)

52
Q

For early degenerative processes and tissue necrosis and demonstrate rickettsia and other bacteria

A

Orth’s Fluid

53
Q

Preserves myelin better than buffered formalin

A

Orth’s Fluid

54
Q

Used in 4% aqueous solution of the basic lead acetate

A

Lead Fixatives

55
Q

Used for acid mucopolysaccharides

A

Lead Fixatives

56
Q

Lead Fixatives fixes ___

A

tissue mucin

57
Q

In lead fixative, CO2 is took up to form insoluble lead carbonate on prolonged standing this maybe removed by

A

maybe removed by adding acetic acid drop by drop to lower pH and dissolves residue

58
Q

Usually used in strong or saturated solutions
2,4,6 trinitrophenol
Explosive when dry

A

Picric Acid

59
Q

Picric Acid is used for

A

Glycogen

60
Q

Picric Acid can be used as ___ and _____ can be seen

A

Can be used as stain (yellow); small tissue fragments can be seen

61
Q

2 fluids under Picric Acid

A

Bouin’s and Brasil

62
Q

embryo and pituitary biopsies
Excellent for soft and delicate sructures
For tissue stained with Masson’s trichrome
NOT for kidney, lipid and mucus

A

Bouin’s

63
Q

Has TCA
Better and less messy than Bouin’s
Excellent for glycogen

A

Brasil’s Alcoholic Picroformol

64
Q

Usually incorporated in compound fixatives
Solidies at 17 C
Precipitates nuceloCHONS, chromatin materials
NOT for cytoplasmic fixation

A

GLACIAL ACETIC ACID

65
Q

Fixes and removes water
Rapidly denatures and precipitates CHONs

A

Alcohol Fixatives

66
Q

Alcohol Fixatives is excellent for..

A

glycogen

67
Q

Alcohol Fixatives dissolves

A

fats and lipids

68
Q

Alcohol Fixatives preserves

A

nuclear stains

69
Q

Fixes chromosomes, lymph glands and urgent biopsies
Fixes and dehydrates

A

Carnoy’s Fluid

70
Q

For nissl granules and cytoplasmic granules

A

Carnoy’s Fluid

71
Q

Acts as both nuclear and biochemical fixative

A

Newcomer’s

72
Q

For mucopolysaccharides and nuclear CHONs

A

Newcomer’s

73
Q

Preserves mitochondria and golgi bodies
Fixation for ultrathin sectioning in EM
Very expensive
Inhibits hematoxylin, volatile
Pale yellow powder dissolves in water
Fats are stained black

A

Osmium Tetroxide

74
Q

it Fixes conjugated fats and lipids
Preserves mitochondria and golgi bodies

A

Osmium Tetroxide

75
Q

Osmium Tetroxide causes

A

Causes conjunctivitis, blindness

76
Q

Osmium Tetroxide inhibits

A

Inhibits hematoxylin, volatile

77
Q

Most common chrome-osmium acetic acid fixative

A

Flemming’s Solution

78
Q

is used for Nuclear preapration (chromosomes)

A

Flemming’s Solution

79
Q

Permanently fixes fats
Requires less than 10x the volume of the tissues to be fixed, very expensive

A

Flemming’s Solution

80
Q

Made up of chromic and osmic acid
Cytoplasmic structures (mitochondria)
Time: 24-48 hrs

A

Flemming’s solution w/o Acetic acid

81
Q

Ppts CHONs
Weak decalcifying agent
Has softening effect on dense fibrous tissues facilitates preparation of such sections
Small pieces of tissues or bones

A

Tricloroacetic Acid

82
Q

Used at ice cold temp ranging from -5 C to 4 C
For water diffusible enzymes (phosphatases and lipases)
For brain tissues (rabies)
Solvent for metallic salts
Dissolves fats, preserves glycogen poorly, evaporates rapidly

A

Acetone