Decalcification Flashcards
Process of removing Calcium or Lime salts from tissue
Decalcification
Performed on bones, teeth, calcified tissues (tuberculous lungs, arteriosclerotic vessels)
Decalcification
It prevents poor cutting of hard tissues/ knife damage
Decalcification
Sensation during cutting
Grating
The tissue surface may reveal __________ and can cause resistance if the paraffin-embedded block has been trimmed
Small foci
These are capable of removing the calcium from the tissues
Decalcifying agents
Most widely used agents for routine decalcification, stable and easily available
Acids
EDTA (versene)
Chelating agents
Ammonium form of polystrene resin;
Ion exchange resins
Attraction of cato negative electrode
Electrical ionization (electrophoresis)
Decalcifying agent that is most common, fastest and inhibits nuclear stain
Nitric acid
Destruction of tissue can be prevented by combining ________________
Formaldehyde or alcohol
What are nitric acid based decalcifying agents
10% aqueous nitric acid
Formol-nitric acid
Perenyi’s fluid
Phloroglucin nitric acid
- A nitric acid based agents that is recommended for urgent biopsy, needle biopsy
- Can produce yellow discoloration, impairing the staining reaction of the tissue
10% aqueous nitric acid
Composed of nitric acid and distilled water
10% aqueous nitric acid
- A nitric based agent that is good nuclear staining, less tissue destruction
- can also produce yellow discoloration
Formol nitric acid
Composed of nitric acid, formalin and distilled water
Formol nitric acid
Lessen yellow tissue discoloration by ___________ in a running tap water for at least 12 hrs
Sodium sulfate
- A nitric acid based agent that decalcifies and softens, good nuclear and cytoplasmic staining
- slow, difficult to assess
Perenyi’s fluid
Can be dissolved by adding glacial acidic acid drop by drop
Perenyi’s fluid
Composed of nitric acid, chromic acid, absolute ETOH
Perenyi’s fluid
- A nitric based acid that is most rapid
- Poor nuclear staining
Phloroglucin nitric acid
Composed of conc. Nitric, phloroglucin, nitric acid
Phloroglucin nitric acid
What are hydrochloric acid based decalcifying agents?
Von ebner’s fluid
Decalcifying agent that is inferior compared to nitric acid, slower action and greater tissue distortion
- Good nuclear staining and recommended for surface decalcification
Hydrochloric acid
- A HCL based agent that is good for cytologic staining, recommended for teeth and small pieces of bones.
- the extent of the decalcification cannot be measured
Von Ebner’s fluid
What are the types of acid that is used for decalcification
Nitric acid
Hydrochloric acid
Formic acid
Trichloroacetic acid
Sulfurous acid
Chromic acid
Citric acid
Decalcifying agent that is better for nuclear staining with less tissue distortion, recommended for postmortem research tissues upon the addition of sodium citrate
Formic acid
What are formic acid based decalcifying agents
10% formic acid
Formic acid sodium citrate solution
- A formic avid based agent that is both fixative and decalcifying agent, permits excellent nuclear and cytoplasmic staining
-slow
10% formic acid
Composed of formic acid and formol saline
10% formic acid
- A formic acid based that is slow and not recommended for routine purposes, requires neutralization with 5% Na sulfate
Formic acid- sodium citrate solution
Composed of formic acid and Na citrate
Formic acid sodium citrate solution
Decalcifying agent that is very slow, weak and it is nor used for dense tissues
Trichloroacetic acid
Composed of trichloroacetic acid and formol saline
Trichloroacetic acid
Decalcifying agents that is very weak and suitable only for minute pieces of bones
Sulfurous acid
Decalcifying agent that is carcinogenic and corrosive to skin
Chormic acid (flemming’s fluid)
Composed of chromic acid, osmium tetroxide and glacial HAC
Chromic acid
Composed of citric acid, ammonium citrate, zinc sulfate and chloroform
Citric acid- citrate buffer (ph 4.5)
What are decalcifying agents that id good for nuclear staining
Formol nitric acid
Perenyi’s fluid
Formic acid
10% formic acid
Formic acid- sodium citrate solution
Trichloroacetic acid
Citric acid
What are decalcifying agents that is good for cytoplasmic staining
Perenyi’s fluid
Von ebner’s fluid
10% formic acid
Citric acid
A type of decalcifying agent that is combine with calcium ions and other salts
Chelating agents
Most common chelating agent will not bind Ca at pH below _______
3.0
Advantage of chelating agents
Produces minimal cell and tissue distortion
Disadvantage of chelating agents
Very slow, EDTA inactivates alkaline phosphates
A type of decalcifying agents that hastens decalcification by removing Ca ions from formic acid containing decalcifying solution
Ion exchange resins
Not recommended for fluids containing mineral acids such as nitric acid and hydrochloric acid
Ion exchange resins
Advantage of ion exchange resins
Excellent staining results
Minimal cell and tissue distortion
Artifacts produced, usually caused by CO2 bubbles
Disadvantage of ion exchange resins
Slow- 1-14 days
Can be measured by physical or x-ray method
Causes light tissue hardening
A type of decalcification whereby positively charged calcium ions are attracted to a negative electrode and subsequently removed from the decalcifying solutions
Electrical ionization (electrophoresis)
What is the difference between the principle applied in the electrophoresis and the agents
Utilizes electricity
Solutions used for electrolytic decalcification
Formic acid, HCL, distilled water
More concentrated acid solution
Decalcify more rapidly but is more harmful to the tissue
Higher concentration and greater amount of fluid
Increase speed of process
Ratio fluid to tissue volume for decalcification
20:1
If temperature is 37C
Impaired nuclear staining of Van Gieson’s stain for collagen fibers
If temperature is 55C
Tissue will undergo complete digestion within 24-48 hrs
If temperature is 18-30C
Optimum temperature= RM temp
It accelerates the rate of diffusion and speeds up the calcification
Mechanical agitation
_______ in size and consistency of tissues will require longer periods for complete decalcification
Increase
The ideal time required for decalcifying tissue
24-48 hrs
These are usually require up to 14 days or longer in order to complete the process
Dense bone tissues
Test for completeness of decalcification
Physical/ mechanical- most inaccurate
X-ray/ radiological- expensive
Calcium oxalate test- recommended for routine purposes
The appearance needed to know if the decalcification is complete
Clear
For post decalcification remove acid by saturated_________ or 5-10% aqueous NaHCO3 for several hours then use running tap water
Lithium carbonate solution
What are the tissue softeners
Perenyi’s fluid
4% aqueous phenol
Molliflex
2% HCl
1% HCl in 70% alcohol