Decalcification-Clearing Flashcards
The most common chelating agent
EDTA with pH 7
The most common decalcifying agent
Nitric acid
It is both a tissue softener and a decalcifying agent
Perenyi’s fluid
It is the most rapid decalcifying agent; overall better than nitric acid
Phloroglucinol-Nitric acid
It is good for nuclear staining
Trichloroacetic acid (TCA)
Both fixative and a decalcifying agent
Formic acid
Chromic acid or Flemming’s fluid
How long is the decalcification time using nitric acid
12-24 hours
Composition of Phloroglucinol-Nitric acid
10 mL concentrated nitric acid
1 g phloroglucin
100 mL 10% nitric acid
Composition of Perenyi’s fluid
40 mL 10% nitric acid
30 mL 0.5% chromic acid
30 mL absolute ethanol
Comparison of nitric acid and phloroglucinol nitric acid
Nitric acid is good for nuclear staining while the latter is not
These decalcifying agents don’t require washing
Von Ebner’s fluid,
TCA
Used for minute bone spicules
Chromic acid
Decalcifying agents that permit good nuclear and cytoplasmic staining
Formic acid
Trichloroacetic acid (TCA)
Citric acid-citrate buffer solution
Require neutralization with 5% sodium sulfate
Phloroglucinol-Nitric acid,
Formic acid
What is the ideal decalcification time
24-48 hours
What is the optimum temperature for decalcification
18-30 deg C
Dense bone tissue require up to _____ weeks to complete decalcification process.
14 days
What is the preferred method of measuring the extent of calcification
Chemical method/calcium oxalate method
Most widely used dehydrating agent
Ethanol
A dehydrating agent that does not dissolve nitrocellulose
Methanol
Superior lipid solvent
isopropanol
It cannot be used for celloidin embedding
Isopropanol
For rapid dehydration of 1 hour
Acetone
It is both a dehydrating and clearing agent
Dioxane
True or False
Long, slow dehydration gives the best results
True
Also known as dealcoholization
Clearing
it is the process of replacing the dehydrating fluid with a fluid that is miscible with both the dehydrating fluid and the impregnating/embedding medium
Clearing
Ideal Characteristics of a Clearing Agent
- Should be miscible with alcohol to promote rapid removal of the dehydrating agent
- Should be miscible and easily removed by melted paraffin wax and/or by mounting medium to facilitate impregnation and mounting sections.
- Should not produce excessive shrinkage, hardening, or damage of tissue
- Should not dissolve aniline dyes
- Should not evaporate quickly +. However, clearing agent should evaporate quickly inside the oven.
- Should make the tissues transparent.
Colorless and mostly used clearing agent
Xylene
The most rapid clearing agent 15-30 mins
Xylene
What is the remedy when Xylene becomes milky due to incomplete dehydration
Immersion of the tissue in absolute alcohol (rehydration)
A substitute for Xylene and Benzene
Toluene
A clearing agent recommended for tough tissues like skin, fibroid, and decalcified tissues; nervous, lymph nodes, and embryos
Chloroform
A disadvantage of chloroform
it does not make the tissue transparent
Slow-acting clearing agents that can be used when double-embedding techniques are required
Methyl benzoate and Methyl salicylate
It is an expensive clearing agent used to clear both paraffin and celloidin sections during embedding process;
Recommended for CNS tissues and cytological studies
Cedarwood oil
Rapid acting but causes brittle and hard tissue;
Causes aplastic anemia
Benzene
Recommended for embryos, insects, and very delicate specimens
Aniline oil
Clearing agents suitable for CNS
Chloroform,Cedarwood oil
Clearing agents suitable for embryos
Chloroform, Aniline oil
