DECALCIFICATION Flashcards
true or false. decalcification is part of routine tissue processing.
false. not all undergo decalcification.
tissue spx that undergo decalcification
bones
teeth
tuberculous organs
arteriosclerotic blood bessels
ratio of decal agent to tissue
20:1
types of decal agents
acids
chelating agents
ion exchange resin
electrical ionization
most widely used for routine decal
acid decal agents
most common and fastest decal agent
nitric acid
recommended conc of nitric acid
5-10%
rapid, recommended for urgent biopsies
aqueous nitric acid (10%) (12-24 hrs)
rapid, produces less tissue destruction
formol-nitric acid (1-3 days)
decal and softens tissue at the same time, slow
perenyi’s fluid (2-7 days)
the MOST rapid decal agent of all
phloroglucin nitric acid (12-24 hrs)
inferior to nitric acid but produces good nuclear staining at 1% conc
hydrochloric acid
decal agent for teeth and small pieces of bones
von ebner’s fluid (derived from HCl)
BEST decal agent
recommended for postmortem research and suitable for immunohistochem staining
5% formic acid
what is added to hasten decal of formic acid?
citrate
both used as a fixative and decal agent.
suitable for small spicules of bone
trichloroacetic acid
very weak decal agent.
suitable for minute pieces of bone
sulfurous acid
carcinogenic decal agent
chromic acid
decal agent that does not produce cell or tissue distortion
citric acid-citrate buffer solution 4.5 pH
chelating agent in decal
EDTA
combine with calcium ions to form weakly dissociated complexes and facilitate the removal of calcium ions
chelating agents
chelating duration
small spx: 1-3 weeks
dense bones: 6-8 weeks or longer
chelating optimum binding capacity
pH 8
true or false. EDTA is not suitable for immunohistochem or enzyme staining and electron microscopy
false. EDTA is excellent to use on these.
this method works by removing calcium ions from formic acid-containing decal solutions
ion exchange resin
what resin is used on ion-exchange resin?
ammonium form of polystyrene resin
ion exchange resin is not recommended on:
nitric acid and hydrochloric acid
which decal agent is added in ion exchange resin?
formic acid (20-30x)
process where positively charged calcium ions are attracted to a negative electrode and subsequently removed from the solution
electrophoresis
time of calcium is shortened due to:
heat and the production of electrolytic reaction
which decal agent is added in electrophoresis?
88% formic acid
hastens decal (3):
concentration
temp
agitation
retards decal:
increase in size and consistency
done by touching or bending the tissue
physical or mechanical test
decal measurement that is routinely used
chemical method
cloudy soln chemical check:
incomplete decal
clear soln chemical check:
complete decal
very expensive but the most ideal, sensitive, and reliable method to determine extent of decal
x-ray or radiologic method
x-ray method is not recommended to what type of tissues?
mercuric chloride-fixed tissues
ways to do post-decal:
- lithium bicarbonate/sodium bicarbonate
- rinse in tap water
- formol-saline w/ sucrose or phosphate-buffered saline w/ sucrose
this may be required for unduly hard tissues
tissue softeners
acts as both decal agent and tissue softener
perenyl’s
tissue softener that makes use of 4% phenol
lendrum’s
tissue softener that leaves a soapy and swollen effect
molliflex
optimum temperature for decalcifying
18-30 C (room temp)
ideal time required:
24-48 hours
