DECALCIFICATION/DEMINERALIZATION Flashcards
Calcium or lime salts are removed from tissues
DECALCIFICATION
Decalcification is done after _____ and before _____
Fixation; Impregnation
Inadequate decalcification results in poor cutting of hard tissues and damage to the knife edge. True or False?
True
Most widely used for routine decalcification; stable, easily available, inexpensive
Acid Decalcifying Agents
Optimum temperature of Acid Decalcifying Agents
18-30/RT
Recommended Tissue:Fluid ratio for decalcification
1:20
MOST COMMONLY USED DECALCIFYING AGENT
NITRIC ACID
Very rapid, produces minimal distortion, recommended for routine purposes/urgent biopsies
Nitric Acid
Nitric acid is easily removed by
70% alcohol
Decalcification time of Nitric acid
12-24 hours
Silver impregnation of nerve fibers
De Castro’s fluid
Less tissue destruction than 10% Aq. HNO3
Formol-Nitric Acid
Decalcification time of Formol-Nitric Acid
1-3 days
Decalcifies and softens tissues, nuclear and cytoplasmic staining is good, maceration is avoided
Perenyi’s Fluid
Decalcification time of Perenyi’s Fluid
2-7 days
Most rapid decalcifier; urgent works
Phloroglucin-Nitric Acid
Decalcification time of Phloroglucin-Nitric Acid
12-24 hours
Surface tissue block
Hydrochloric acid
Routine post-mortem research tissues
Formic acid
Decalcification time of Formic acid
2-7 days
No washing-out required; permits good staining
TCA
Decalcification time of TCA
4-8 days
Decalcifier and tissue softener
Perenyi’s fluid
Minute pieces of bones
Sulfurous acid
Minute bone spicules
Chromic acid (Flemming’s Fluid)
Excellent nuclear and cytoplasmic staining
Citric acid-citrate buffer solution (pH 4.5)
Teeth and small pieces of bone
Von Ebner’s fluid
Nails
Lendrum’s fluid
Substances which combine with calcium ions and other salts to form weakly dissociated complexes and facilitate removal of calcium salt
CHELATING AGENTS
Most common chelating agent
EDTA (Versene)
Decalcification time of chelating agents
1-3 weeks
Chelating agents are rapid and recommended for urgent biopsies. True or False?
False; Very slow, Not recommended
Hastens decalcification by removing calcium ions from Formic Acid-containing decalcifying solutions, thereby increasing solubility from the tissue
ION EXCHANGE RESINS
Process whereby positively charged calcium ions are attracted to a negative electrode and subsequently removed from the decalcifying solution
ELECTROPHORESIS (ELECTRICAL IONIZATION)
Utilizes electricity to remove the calcium deposits
ELECTROPHORESIS (ELECTRICAL IONIZATION)
THREE WAYS TO MEASURE THE EXTENT OF DECALCIFICATION
PHYSICAL OR MECHANICAL TEST
X-RAY OR RADIOLOGICAL METHOD
CHEMICAL METHOD
Done by touching or bending the tissue, pricking the tissue with a fine needle or probe
PHYSICAL OR MECHANICAL TEST
Most ideal and reliable way to measure extent of decalcification, very expensive
X-RAY OR RADIOLOGICAL METHOD
Simple, reliable and convenient, recommended for routine purposes, to detect the presence of calcium in the decalcifying solution
CHEMICAL METHOD
For unduly hard tissues which are liable to damage the microtome knives
TISSUE SOFTENERS
TISSUE SOFTENERS
HaHa PePhe Mo - MALAMBOT
HCl
1% HCl in 70% alcohol
Perenyi’s fluid
4% aq. Phenol
Molliflex
