PRELIM: CH8 Decal (2)

Removing purine and pyrimidine bases

Prolonged exposure to acid decalcifiers may interfere with DNA by:

To remove residual acid that could continue damaging tissue

After acid decalcification is complete, why is thorough washing important?

Strong mineral acids

Which class of decalcifying agents is generally fastest?

Hydrochloric and nitric acids

Strong mineral acids commonly used for decalcification include:

They are rapid but can damage tissue and impair staining if exposure is excessive

What is the major trade-off when using strong mineral acids?

Nitric acid

Which acid is described in the notes as the most common and fastest decalcifying agent?

10 mL concentrated nitric acid + distilled water to 100 mL

A 10% aqueous nitric acid solution is being prepared. Which formula is correct according to the notes?

12–24 hours

What is the approximate decalcification time for 10% aqueous nitric acid?

10% nitric acid

A patient requires an urgent small bone biopsy diagnosis within approximately 24 hours. Which agent would be most appropriate based on the notes?

Tissue distortion and impaired stainability

Which is a disadvantage of prolonged nitric acid decalcification?

They may be especially damaging to tissue and should be replaced with fresh stock solution

Why can old nitric acid solutions be particularly problematic?

Damage tissue antigens and cause loss of enzyme activity

Strong acids may be particularly problematic when immunohistochemistry (IHC) is planned because they can:

Distilled water

Formol-nitric acid contains nitric acid, formaldehyde, and:

It produces less tissue destruction while remaining relatively rapid

What is one advantage of formol-nitric acid over 10% aqueous nitric acid?

Perenyi's fluid

Which decalcifying fluid contains nitric acid, chromic acid, and absolute ethyl alcohol?

It decalcifies and softens tissues simultaneously

What is a major advantage of Perenyi's fluid?

It acts relatively slowly on dense bone

Why is Perenyi's fluid not ideal for urgent diagnosis of dense bone?

Phloroglucin-nitric acid

Which decalcifying agent is described as particularly rapid and useful for urgent cases but associated with poor nuclear staining?

Acts more slowly and produces greater tissue distortion

Hydrochloric acid (HCl) is generally considered inferior to nitric acid because it:

Hydrochloric acid

HCl stands for:

Surface decalcification of tissue blocks

Which application is particularly appropriate for a 1% HCl solution in 70% alcohol?

Teeth and small pieces of bone

Von Ebner's fluid is particularly recommended for:

Formic acid

Which weak acid is widely used for routine decalcification because it is gentler than strong mineral acids?

Better tissue preservation and nuclear staining are desired

Formic acid is generally preferred over strong acids when:

It is slower

What is a major disadvantage of formic acid compared with nitric acid?