Metallic Fixatives Flashcards

1
Q

Good general fixative for all kinds of tissue;

May act as mordant;

For trichrome staining;

For tissue photography

A

Zenker’s Fluid

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2
Q

For pituitary gland, bone marrow, and blood-containing organs (e.g. liver & spleen)

A

Zenker-formol/Helly’s

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3
Q

Removes excess mercury

A

Alcoholic iodine

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4
Q

Removes excess iodine

A

5% sodium thiosulfate

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5
Q

Recommended for tumor biopsies especially of the skin;

Do not produce black precipitate

A

Heidenhain’s Susa

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6
Q

Used on wet smears for cytologic exams

A

Schaudinn’s Solution/Sublimated alcohol

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7
Q

Commonly used for bone marrow biopsies;

Rapid fixation: 1.5-2 hrs

A

B-5 fixative

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8
Q

Rapid fixatives; excellent nuclear preservation

A

Carnoy-Lebrun

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9
Q

Rapid fixatives; excellent nuclear preservation

A

Ohlmacher

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10
Q

Precipitate proteins and preserve CHO

A

Chromate fixative

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11
Q

For Chromaffin tissues, Adrenal medulla, and Mitochondria

A

Chromate fixative

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12
Q

Precipitates all proteins;

Adequately preserve CHO;

A

Chromic acid

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13
Q

Demonstrate chromatin, mitochondria, mitotic figures, golgi bodies, rbc’s, and colloid-containing tissues

A

Regaud’s Fluid

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14
Q

For study of early degenerative processes and tissue necrosis;

Demonstrate Rickettsia;

Preserves myelin better

A

Orth’s Fluid

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15
Q

Preserves mitochondria (4.5-5.2);

Fixes lipids

A

Potassium dichromate

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16
Q

Chemical name for the general picric acid fixative

A

2-4-6-trinitrophenol

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17
Q

Fixation of embryos and pituitary biopsies;

Fixative for preserving soft and delicate structures (e.g. endometrial curettings);

Yellow stain is useful in fragmentary biopsies;

Fixative for Masson’s Trichrome;

Destroy cytoplasmic structures

A

Bouin’s solution

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18
Q

Best routine fixative for glycogen

A

Brasil’s alcoholic picroformol fixative

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19
Q

Anhydrous;

Solidify @ 17degC;

Precipitates chromosomes and chromatin materials

A

Glacial acetic acid

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20
Q

Diluent for wright’s stain;

Fix wet/dry smears, blood smears, BM tissues

A

Methanol 100%

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21
Q

For fixing touch preps

A

Isopropanol 95%

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22
Q

Fixes blood, tissue films, smears

For enzyme studies

Both used as simple/compound fixative

A

Ethanol

23
Q

Most rapid fixative

A

Carnoy’s Fluid

24
Q

Fix brain tissue for rabies diagnosis; demonstrate Negri bodies

A

Carnoy’s Fluid

25
Q

Preserves Nissl granules

A

Carnoy’s Fluid

26
Q

Preserves glycogen; for sputum cytology

A

Alcoholic Formalin/Gendre’s Fixative

27
Q

Fix mucopolysaccharides and nuclear proteins

A

Newcomer’s Fluid

28
Q

Better reaction in Feulgen than Carnoy’s

A

Newcomer’s fluid

29
Q

Both nuclear and histochemical fixative

A

Newcomer’s fluid

30
Q

Excellent for nuclear structures such as chromosomes; permanently fixes fat

A

Flemming’s solution

31
Q

Recommended for cytoplasmic structures such as mitochondria

A

Flemming’s solution w/o Acetic acid

32
Q

Used at ice cold temp; study of water diffusable enzymes (lipase&phosphatase); fix brain tissues for diagnosis of rabies (Negri bodies); used in freeze substitution; volatile & flammable

A

Acetone

33
Q

Two constituents dissolved by heat fixation

A

(1) starch (2) glycogen

34
Q

2 most commonly used fixatives for general use

A

(1) 10% formol-saline (2) Zenker’s fluid

35
Q

Best general tissue fixative

A

10% NBF

36
Q

Used in cryostat sections for demonstrating lipids

A

Mercuric chloride, K dichromate

Best: 10% NBF

37
Q

Fixes cholesterol for ultrastructural demonstration

A

Digitonin

38
Q

For improved ultrastructural demonstration of lipids

A

Imidazole osmium tetroxide

39
Q

Generally recommended for glycogen fixation

A

Alcoholic fixatives

40
Q

Better fixative in human skin compared with NBF

A

Alcoholic formaldehyde

41
Q

For protein fixation/amino acid histochemistry

A

10% NBF or formaldehyde vapor

42
Q

Alcohol-based fixative most useful for glycogen fixation

A

(1) Rossman’s fluid (2) cold absolute alcohol

43
Q

Coating for better retention of glycogen

A

Celloidin

44
Q

Paraformaldehyde-glutaraldehyde (EM and electron immunocytochemistry)

A

Karnovsky’s

45
Q

Mixture with glutaraldehyde or formaldehyde

A

Acrolein

46
Q

Primary fixatives for EM

A

(1) glutaraldehyde
(2) osmium tetroxide
(3) paraformaldehyde

-@ 4degC

47
Q

Fixation is retarded by

A

(1) size & thickness
(2) mucus
(3) fats
(4) blood
(5) cold temp
(6) hot temp

48
Q

Fixation is enhanced by

A

(1) size & thickness
(2) agitation
(3) moderate heat (37-56degC)

49
Q

Failure to fix immediately

A

Autolysis

50
Q

Prolonged fixation

A

Too brittle/ too hard

51
Q

Incomplete fixation

A

Soft and feather-like

52
Q

Wrong choice of fixative

A

(1) Enzyme inactivation/loss
(2) Removal of fixative soluble substances

53
Q

Incomplete washing of fixative

A

Presence of artefact pigments

54
Q

Overfixation

A

Shrinkage and swelling