02 Decalcification Flashcards
a specialized connective tissue
bone
the bone has a hard, rigid nature due to the inclusion of minerals in its ___ ___
osteoid matrix
crystalline component of the bone
hydroxyapatite
serves as a reservoir for a multitude of inorganic ions
hydroxyapatite
interfere with the accurate evaluation an examination of histologic sections
calcium (lime salt)
calcified specimen will not section properly due to the difference in ___ between ___ and ___
densities
calcium
paraffin
T/F: calcium may be present in the arteriosclerotic vessel
T
a procedure that removes calcium from calcified tissues
decalcification
Decalcification happens after ___ and before ___
fixation
impregnation
done to make the tissue soft enough to section in paraffin
decalcification
this process makes the bone thin enough for histological observation
grinding
in this process, the canaliculi and cell lacunae are well-seen
ground sections
organic compounds capable of binding with certain metals
chelating agents
chelating agents are typically very ___ and ___
slow acting
gentle
chelating agents are used for ___ ___ and ___ studies
electron microscopy
immunohistochemistry
a process whereby positively charged calcium ions are attracted to a negative electrode and subsequently removed from the decalcifying solution
electrophoresis
this reduces the effects of decalcifying agents on staining
post-decalcification
a tiny abnormal deposit of calcium salts that is often an indicator of cancer
microcalcification
microcalcification is most common in which tissue sample?
female breast
microcalcification appear as ___ ___ granular masses with lighter ___ ___
dark purple
purple halos
the purple halos in the microcalcification is stained with ___
hematoxylin
decalcifying agent:
for routine decalcification of large amounts of bony tissue
acids
decalcifying agent (acid):
most common
nitric acid
decalcifying agent (acid):
fastest
nitric acid
decalcifying agent (acid):
recommended for routine purposes
nitric acid
decalcifying agent (acid):
inhibit nuclear stain
nitric acid
decalcifying agent (acid):
destroy tissues
nitric acid
decalcifying agent (acid):
Perenyi’s fluid
nitric acid
decalcifying agent (acid):
mot rapid decalcifying agent
Phloroglucin-Nitric acid
In decalcification, acid must be removed by ___ changes of EtOH
3
decalcifying agent (acid):
slower
hydrochloric acid
decalcifying agent (acid):
greater distortion
hydrochloric acid
decalcifying agent (acid):
good nuclear staining
hydrochloric acid
decalcifying agent (acid):
Von Ebner’s fluid
hydrochloric acid
decalcifying agent (acid):
slow
hydrochloric acid
decalcifying agent (acid):
greater distortion
hydrochloric acid
decalcifying agent (acid):
good nuclear staining
hydrochloric acid
decalcifying agent (acid):
Von Ebner’s fluid
hydrochloric acid
decalcifying agent (acid):
safer
formic acid
decalcifying agent (acid):
better nuclear staining
formic acid
decalcifying agent (acid):
recommended for routine decalcification of postmortem research tissues
formic acid
decalcifying agent (acid):
the only weak acid used extensively as a primary decalcifying agent
formic acid
in formic acid-sodium citrate solution, the citrate ___ decalcification by ___ the calcium
accelerates
chelating
T/F: fixed specimens hastens decalcification
F (it slows down the digestion of cellular and other tissue components)
fixed specimens are damaged by ___ exposure to ___ decalcifying agents
prolonged
acid
the most common chelating agent
EDTA
chelating agent:
for detailed microscopic studies
EDTA
chelating agent:
binds calcium forming an insoluble non-ionized complex
EDTA
T/F: overexposure to EDTA can remove proteoglycans and weaken staining
T
T/F: EDTA easily penetrates the tissue
F (it penetrates tissue poorly)
optimal binding pH of EDTA
8 and above
this hastens decalcification by removing calcium form formic acid containing-solution
ion exchange resin
in using ion exchange resin, the degree of decalcification can be measured by ___ or ___ method
physical
x-ray
decalcifying agent:
shortened time for decalcification due to heart and electrolytic reaction
electrophoresis
decalcifying agent:
dependent upon a supply direct current to remove calcium
electrophoresis
decalcifying agent:
satisfactory for small bone fragments
electrophoresis
T/F: one of the disadvantages of electrophoresis is that it can process only a limited number of specimens at a time
T
T/F: electrophoresis is often used a routine decalcifying agent
F (not suited for routine daily use)
optimum temperature for decalcification
18-30C
the recommended fluid to tissue volume ratio
20:1
ideal time for decalcification
24-48 hrs
the calcium ions that have been removed can saturate the solution around the specimen and prevent further decalcification if the solution is not ___ and ___ ___
agitated
change regularly
too rapid removal of calcium can cause (4)
complete digestion of tissue
marked swelling
hydrolysis of bony matrix
poor staining capacity of the cell
methods used to determine the extent of decalcification (4)
physical
mechanical
chemical
x-ray or radiological
method used to determine the extent of decalcification:
physical: touching or bending the tissue with ___ to determine the consistency of tissues
fingers ><
method used to determine the extent of decalcification:
diminished consistency and softer
physical
method used to determine the extent of decalcification:
vague and inaccurate
physical
method used to determine the extent of decalcification:
done by pricking the tissue
mechanical
method used to determine the extent of decalcification:
instrument used for mechanical method
fine needle or a probe
method used to determine the extent of decalcification:
produce needle tract artifacts
mechanical
method used to determine the extent of decalcification:
destroy important cellular details
mechanical
method used to determine the extent of decalcification:
most ideal, sensitive, and reliable
radiological
method used to determine the extent of decalcification:
detect even the smallest focus of calcium
radiological
method used to determine the extent of decalcification:
very expensive
radiological
T/F: radiological method of determining the extent of decalcification is for mercuric chloride-fixed tissues
F (not used because of its radio-opacity)
method used to determine the extent of decalcification:
simple, reliable, convenient
chemical
method used to determine the extent of decalcification:
for routine purposes
chemical
reagents used for the chemical method which detects calcium by precipitation
Ca(OH)2 or CaC2O4
Chemical decalcifying solutions
concentrated NH4OH
saturated (NH4)2C2O4
method used to determine the extent of decalcification:
performed on the discarded fluid using litmus paper
chemical
in the chemical method of determining the degree of decalcification, a clear solution means ___
complete decalcification
in the chemical method of determining the degree of decalcification, a cloudiness or precipitation solution means ___
incomplete decalcification
this shows a marked loss of nuclear haematoxyphilia
over-decalcification
T/F: over-decalcification can be presented at a strongly eosin-stained tissue
T
reagents used for post-decalcification
saturated Li2CO3
5-10% NaHCO3
Decalcified samples is stored in formol saline containing ___ ___ or PBS with ___ ___ at 4C
15% sucrose
15-20% sucrose
tissue softeners used during decalcification (5)
Perenyi’s fluid
4% aqueous phenol
Molliflex
2% HCl
1% HCl in 70% alcohol