SAS 4: Decalcification

Question 1

is the removal of calcium ions from a bone or calcified tissue through a histological process that makes them flexible and easier to cut

Answer 1

Decalcification

Question 2

The principle of decalcification is

Answer 2

Strong mineral acids - 10% hydrogen chloride
Weak organic acids - 5-10% formic acid

Question 3

the recommended ratio of fluid to tissue volume for decalcification is

Answer 3

20:1

Question 4

Temperature of impaired nuclear staining of Van Gienson’s stain for collagen fibers

Answer 4

37 degree celsius

Question 5

Temperature of tissue will undergo complete digestion within 24-48 hours

Answer 5

55 degree celsius

Question 6

Calcium may be removed by the ff:

Answer 6

Acids
Chelating agents
Ion exchange resins
electrical ionization

Question 7

What are the acid decalcifying agents

Answer 7

• Nitric acid
• Hydrochloric acid
• Formic acid
• Trichloroacetic acid
• Sulfurous acid
• Chromic acid
• Citric acid

Question 8

most common and fastest decalcifying agent used

Answer 8

Nitric acid

Question 9

Disadvantage of Nitric acid

Answer 9

progressive tissue damage

Question 10

acts as both tissue softener and decalcifying agent

Answer 10

Perenyi’s fluid

Question 11

recommended for routine purposes

Answer 11

Perenyi’s fluid

Question 12

decalcifying time for Phloroglucin-Nitric acid

Answer 12

12-24 hours

Question 13

most rapid decalcifying agent

Answer 13

Phloroglucin-Nitric acid

Question 14

it is rapid in action, produces minimum distortion of tissues and produces good nuclear staining

Answer 14

Aqueous nitric add solution 10%

Question 15

it is composed of concentrated nitric acid, formaldehyde, and distilled water

Answer 15

Formol-Nitrci acid

Question 16

Decalcifying time of Formic-Nitric acid

Answer 16

1-3 days

Question 17

it is recommended for routine decalcification of postmortem research tissues

Answer 17

Formic Acid

Question 18

Decalcifying time of Formic acid

Answer 18

2-7 days

Question 19

Both fixative and decalcifying agent

Answer 19

Formic acid

Question 20

it is inferior compared to nitric acidin its role as a decalcifying agent because of its slower action and greater distortion of tissues produced

Answer 20

Hydrochloric acid

Question 21

Weak decalcifying agent, not used for dense bone tissues

Answer 21

Trichloroacetic acid

Question 22

Decalcifying time of Trichloroacetic acid

Answer 22

4-8 days

Question 23

Very weak decalcifying agent, suitable for minute pieces of bone

Answer 23

Sulfurous acid

Question 24

Both fixative and decalcifying agent and may be used for decalcifying minute bone spicules

Answer 24

Chromic acid (Flemming’s fluid)

Question 25

It permits excellent nuclear and cytoplasmic staining and doesn't produce well distortion

Answer 25

Citric acid

Question 26

Decalcifying time of Citric acid

Answer 26

6 days

Question 27

substances which combine with calcium ions and other salts to form weakly dissociated complexes and facilitate removal or calcium salt

Answer 27

Chelating agents

Question 28

hastens decalcification by removing calcium ions from formic-acid containing decalcifying solutions

Answer 28

Ion exchange resin

Question 29

It is a process whereby positively charged calcium ions attracted to the negative electrode and subsequently removed from the decalcifying solution

Answer 29

electrophoresis

Question 30

This method is satisfactory for small bone fragments, processing only a limited number of specimens at a time

Answer 30

Electrophoresis

Question 31

It has been used quite often for tissue processing, but there are very few studies describing its use in decalcification of bone or teeth

Answer 31

Microwave oven decalcification

Question 32

Factors influencing decalcification

Answer 32

- concentration - fluid access - size and consistency - agitation - temperature

Question 33

The 3 ways to measure extent of decalcification

Answer 33

- Physical/Mechanical test - X-ray or Radiological method - Chemical method

Question 34

it requires manipulation, bending, probing and trimming of the specimen to feel for remaining calcified areas

Answer 34

Physical/Mechanical test

Question 35

very expensive, "Most ideal, Most sensitive, most reliable" and it's not recommended for mercuric chloride fixed tissue

Answer 35

X-ray or Radiological method

Question 36

The decalcifying agent is usually changed every 24-48 hours and the chemical test is done on the discarded fluid

Answer 36

Chemical method

Question 37

it is simple, reliable, and recommended for routine purposes

Answer 37

Chemical method

Question 38

What are the tissue softeners:

Answer 38

- 4% aq. phenol - molliflex - 2% HCl - 1% HCl in 70% alcohol - Perenyi's fluid - decalcifying agent and tissue softener at the sane time