Fixatives Mercuric Chloride

Question 1

● Most common metallic fixatives; 5-7%
● ADV: penetrates and hardens tissue rapidly
● Routine fixative of choice for preservation of cell in TISSUE PHOTOGRAPHY
● Trichrome staining is excellent
● DADV: banned worldwide d/t extreme toxicity; marked cell shrinkage
→ Remedy: add acid
● Precaution may form black precipitates of mercury except in Heidenhain’s Susa
→ Remedy: DEZENKERIZATION
→ 0.5% Iodine + 70% ETOH -> H20 -> 5% Na thiosulfate -> H20

Answer 1

MERCURIC CHLORIDE

Question 2

● HgCI2 + potassium dichromate + GALACTIC ACETIC ACID
● Good general fixative for adequate reservation of all kinds of tissues

Answer 2

ZENKER’S FLUID

Question 3

● HgCI2 + potassium dichromate + STRONG FORMALIN (40%)
● For pituitary gland, bone marrow, BLOOD-CONTAINING ORGANS, preserves
● Brown pigments are removed with saturated alcoholic picric acid or NaOH

Answer 3

ZENKER-FORMOL (HELLY’S SOLl’N)

Question 4

● HgCI2 + NaCI + TCA + GALACTIC ACETIC ACID + formalin
● Skin tumor biopsy
● ADV: minimum cell shrinkage and tissue hardening due to COUNTERBALANCE effect of acids and mercury
→ Acids: swelling
→ Mercury: shrinkage
● Does not produce black pigment
● DADV: Weigert’s staining of elastic fibers not possible

Answer 4

HEIDENHAIN’S SUSA SOL’N [Su=sublimate; Sa=saure (acid)]

Question 5

● Recommended for hematopoietic and lymphoid tissues
● FT: 4-8 hrs
● Bone marrow biopsies

Answer 5

B-5 FIXATIVE

Question 6

● Recommended for making smears of loose cells on slides.

Answer 6

SCHAUDINN’S FLUID