METALLIC FIXATIVES

Question 1

Mercuric Chloride

Answer 1

Zenker
Zenker-Formol (Hellv’s)
Carnoy-Lebron
Heidenhain’s Susa
B5
Schaudinn’s

Question 2

Chromates

Answer 2

Chromic acid
Regaurd’s/Muller’s
‘Orth’s
Potassium dichromate

Question 3

Most common metallic fixative; 5-7%

Answer 3

MERCURIC CHLORIDE

Question 4

• Routine fixative of choice for preservation of cell detail in tissue photography

Answer 4

MERCURIC CHLORIDE

Question 5

•
•
Advantage: penetrates and hardens tissue rapidly
Disadvantage: Banned worldwide due to extreme toxicity; marked cell shrinkage
• Remedy: add acid

Answer 5

Mercuric chloride

Question 6

Mercuric chloride

• Precautions:
May form____ precipitates of mercury except in______

Remedy:_______
• 0.5% iodine + 70% TOH -» H20 -> 5% Na thiosulfate -> H20

Answer 6

black

Heidenhain’s Susa

Dezenkerization

Question 7

• HgCI2 + Potassium dichromate + glacial acetic acid

Answer 7

Zenker’s Fluid

Question 8

• Good general fixative for adequate preservation of all kinds of tissues

Answer 8

Zenker’s fluid

Question 9

• HgC12 + potassium dichromate + strong formalin (40%)

Answer 9

Zenker-Formol (Helly’s Solution)

Question 10

• For pituitary gland, bone marrow, & blood-containing organs

• Brown pigments are removed with ______ or ______-

Answer 10

Zenker-Formol ( Helly’s sol.)

saturated alcoholic picric acid or NaOH

Question 11

Heidenhain’s Susa solution

Su =
Sa =

Answer 11

sublimate

saure (acid)

Question 12

• HgC12 + NaCl + TCA + glacial acetic acid + formalin
• Skin tumor biopsy

Answer 12

Heidenhain’s Susa sol.

Question 13

• HgC12 + NaCl + TCA + glacial acetic acid + formalin
• Skin tumor biopsy

Answer 13

Heidenhain’s Susa sol.

Question 14

• Advantage: minimum cell shrinkage and tissue hardening due to counter-balance effect of acids and mercury
• Acids: swelling
• Mercury: shrinkage

• Does not produce black pigments

• Disadvantage: Weigert’s staining of elastic fibers not possible

Answer 14

Heidenhain’s Susa sol.

Question 15

• Recommended for hematopoietic and lymphoid tissues
• Fixation Time:______
• Bone marrow biopsies

Answer 15

B-5 Fixative

4-8hrs

Question 16

• Recommended for making smears of loose cells on slides

Answer 16

Shaudinn’s Fluid

Question 17

• Preserves carbohydrates; precipitates all protein

Answer 17

Chromic Acid 1-2%

Question 18

• For chromatin, mitochondria, mitotic figures, golgi bodies, RBC and colloid containing tissues

Disadvantage: prolonged fixation may lead to blackening of tissue pigment
• Remedy: Wash in running tap H2O before dehydration

Answer 18

Regaud’s / Muller’s Fluid

Question 19

Study of early degenerative processes and necrosis; Rickettsiae and other bacteria

• Preserves myelin

Answer 19

Orths’ Fluid

Question 20

Preserves lipids & mitochondria at pH 4.5
to 5.2; cytoplasm, chromatin and chromosome are fixed

Corrosive, thus avoid skin contact

Answer 20

Potassium Dichromate

Question 21

Preserves acid mucopolysaccharide

Disadvantage: prolonged staining —> formation of insoluble lead carbonate

Remedy: add drops of acetic acid to
dissolve residue

Answer 21

LEAD FIXATIVES