Fixation - Histopath Flashcards
(45 cards)
- The most rapid tissue fixative
- Recommended for fixing chromosome, lymph
glands and urgent biopsies
Carnoy’s Fluid
metal (mercury) → cell shrinkage
Su (sublimat)
The process of placing an already fixed tissue in a second fixative
SECONDARY FIXATION
formalin used to preserve phospholipids
Calcium acetate
formalin
- Traditionally, it is the most commonly used fixative in
pathology - Best fixative for central nervous tissues and general postmortem tissues for histochemical examination.
10% Formol-Saline
The process of removing excess fixative from the tissue after fixation in order
to improve staining and remove artifacts from the tissue.
WASHING OUT
-The most effective aldehyde for protein cross-linking
-most useful primary fixatives for electron microscopy
GLUTARALDEHYDE
It precipitates all proteins and adequately preserves carbohydrates.
Chromic acid
polymerized form of formaldehyde, suitable for paraffin embedding and sectioning
paraformaldehyde
Fixes and precipitates nucleoproteins
Glacial Acetic Acid
Used on wet smears for cytologic examinations.
Schaudinn’s
Solution
gas produced by oxidation of methanol
FORMALDEHYDE
Recommended for tumor biopsies especially of the
skin
Heidenhain’s
Susa
solution
Excellent for fixing wet and dry smears, blood
smears and bone marrow tissues
Methyl Alcohol
o Involves placing formaldehyde fixed specimens in acetone, 28%
ammonia water and hydrogen peroxide.
o It uses 70% alcohol as a rinsing agent.
Lillie’s Method
Adequately fixes materials for ultrathin sectioning in electron microscopy,
since it rapidly fixes small pieces of tissues and aids in their staining
Osmic Acid
A secondary fixation whereby a primary fixed tissue is placed in aqueous solution of 2.5 – 3% potassium dichromate for 24 hours, to act as mordant for
better staining effects and to aid in cytologic preservation of tissues.
POST-CHROMATIZATION
- AKA: Post-chroming or Post-mordanting
- For fixing mucopolysaccharides and nuclear
proteins - It is both a nuclear and histochemical fixative.
Newcomer’s Fluid
acetone is used at what ice cold temperature
-5 to 4oC
acid (trichloroacetic acid) → cell
swelling
Sa (saure)
- Commonly used for bone marrow biopsies.
B-5 Fixative
Excellent for glycogen demonstration
Picric Acid Fixatives
- It fixes blood, tissue films and smears
- Used for histochemistry especially for enzyme
studies - Can be both used as a simple and compound
fixative.
Ethyl Alcohol
- Preserves lipid and mitochondria (pH 4.5-5.2)
Potassium
dichromate
