Metallic Fixatives

Question 1

Good general fixative for all kinds of tissue;

May act as mordant;

For trichrome staining;

For tissue photography

Answer 1

Zenker’s Fluid

Question 2

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

Answer 2

Zenker-formol/Helly’s

Question 3

Removes excess mercury

Answer 3

Alcoholic iodine

Question 4

Removes excess iodine

Answer 4

5% sodium thiosulfate

Question 5

Recommended for tumor biopsies especially of the skin;

Do not produce black precipitate

Answer 5

Heidenhain’s Susa

Question 6

Used on wet smears for cytologic exams

Answer 6

Schaudinn’s Solution/Sublimated alcohol

Question 7

Commonly used for bone marrow biopsies;

Rapid fixation: 1.5-2 hrs

Answer 7

B-5 fixative

Question 8

Rapid fixatives; excellent nuclear preservation

Answer 8

Carnoy-Lebrun

Question 9

Rapid fixatives; excellent nuclear preservation

Answer 9

Ohlmacher

Question 10

Precipitate proteins and preserve CHO

Answer 10

Chromate fixative

Question 11

For Chromaffin tissues, Adrenal medulla, and Mitochondria

Answer 11

Chromate fixative

Question 12

Precipitates all proteins;

Adequately preserve CHO;

Answer 12

Chromic acid

Question 13

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

Answer 13

Regaud’s Fluid

Question 14

For study of early degenerative processes and tissue necrosis;

Demonstrate Rickettsia;

Preserves myelin better

Answer 14

Orth’s Fluid

Question 15

Preserves mitochondria (4.5-5.2);

Fixes lipids

Answer 15

Potassium dichromate

Question 16

Chemical name for the general picric acid fixative

Answer 16

2-4-6-trinitrophenol

Question 17

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

Answer 17

Bouin’s solution

Question 18

Best routine fixative for glycogen

Answer 18

Brasil’s alcoholic picroformol fixative

Question 19

Anhydrous;

Solidify @ 17degC;

Precipitates chromosomes and chromatin materials

Answer 19

Glacial acetic acid

Question 20

Diluent for wright’s stain;

Fix wet/dry smears, blood smears, BM tissues

Answer 20

Methanol 100%

Question 21

For fixing touch preps

Answer 21

Isopropanol 95%

Question 22

Fixes blood, tissue films, smears

For enzyme studies

Both used as simple/compound fixative

Answer 22

Ethanol

Question 23

Most rapid fixative

Answer 23

Carnoy’s Fluid

Question 24

Fix brain tissue for rabies diagnosis; demonstrate Negri bodies

Answer 24

Carnoy’s Fluid

Question 25

Preserves Nissl granules

Answer 25

Carnoy's Fluid

Question 26

Preserves glycogen; for sputum cytology

Answer 26

Alcoholic Formalin/Gendre's Fixative

Question 27

Fix mucopolysaccharides and nuclear proteins

Answer 27

Newcomer's Fluid

Question 28

Better reaction in Feulgen than Carnoy's

Answer 28

Newcomer's fluid

Question 29

Both nuclear and histochemical fixative

Answer 29

Newcomer's fluid

Question 30

Excellent for nuclear structures such as chromosomes; permanently fixes fat

Answer 30

Flemming's solution

Question 31

Recommended for cytoplasmic structures such as mitochondria

Answer 31

Flemming's solution w/o Acetic acid

Question 32

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

Answer 32

Acetone

Question 33

Two constituents dissolved by heat fixation

Answer 33

(1) starch (2) glycogen

Question 34

2 most commonly used fixatives for general use

Answer 34

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

Question 35

Best general tissue fixative

Answer 35

10% NBF

Question 36

Used in cryostat sections for demonstrating lipids

Answer 36

Mercuric chloride, K dichromate Best: 10% NBF

Question 37

Fixes cholesterol for ultrastructural demonstration

Answer 37

Digitonin

Question 38

For improved ultrastructural demonstration of lipids

Answer 38

Imidazole osmium tetroxide

Question 39

Generally recommended for glycogen fixation

Answer 39

Alcoholic fixatives

Question 40

Better fixative in human skin compared with NBF

Answer 40

Alcoholic formaldehyde

Question 41

For protein fixation/amino acid histochemistry

Answer 41

10% NBF or formaldehyde vapor

Question 42

Alcohol-based fixative most useful for glycogen fixation

Answer 42

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

Question 43

Coating for better retention of glycogen

Answer 43

Celloidin

Question 44

Paraformaldehyde-glutaraldehyde (EM and electron immunocytochemistry)

Answer 44

Karnovsky's

Question 45

Mixture with glutaraldehyde or formaldehyde

Answer 45

Acrolein

Question 46

Primary fixatives for EM

Answer 46

(1) glutaraldehyde (2) osmium tetroxide (3) paraformaldehyde -@ 4degC

Question 47

Fixation is retarded by

Answer 47

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

Question 48

Fixation is enhanced by

Answer 48

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

Question 49

Failure to fix immediately

Answer 49

Autolysis

Question 50

Prolonged fixation

Answer 50

Too brittle/ too hard

Question 51

Incomplete fixation

Answer 51

Soft and feather-like

Question 52

Wrong choice of fixative

Answer 52

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

Question 53

Incomplete washing of fixative

Answer 53

Presence of artefact pigments

Question 54

Overfixation

Answer 54

Shrinkage and swelling