DECALCIFICATION Flashcards

1
Q

Purpose of Decalcification

A

Purpose:

• Removal of calcium and lime salts

• Done after fixation and before dehydration and impregnation

• Calcium might interfere with accurate evaluation and examination

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2
Q

Significance of Decalcification

A

• Facilitate normal cutting of tissue in sectioning

• Prevent obscuring microanatomical detail of tissue

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3
Q

Organs that require decalcification:

A

• Bones
• Tuberculous Lungs
• Arteriosclerotic Vessels
• Teeth

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4
Q

Characteristics of a good decalcifying agent

A

• Rapid, cheap, inexpensive
• Should also render best and accurate result
• Safe
• Readily available

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5
Q

Unique characteristics of a decalcifying agent

A

Stable
Easily available
Inexpensive
Easy to prepare

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6
Q

Factors affecting the rate of decalcification

A

Concentration
Tissue-to-Volume ratio
Temperature
Mechanical agitation
Size and consistency of tissue sample

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7
Q

If agent is less concentrated…

A

Slow acting

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8
Q

What is the tissue to volume ratio

A

1 : 20

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9
Q

It is the key to a rapid decalcification of tissue

A

Mechanical agitation

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10
Q

If the tissue is large and thick…

A

Longer decalcification process

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11
Q

Four types of decalcifying agents

A

Acid
Chelating agents
Ion exchange resin
Electrophoreis

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12
Q

Type of acids used in decalcification

A

Nitric acid
HCl
Formic acid
Trichloroacetic acid
Sulfurous acid
Chromic acid
Citric acid-Citrate buffer sol.

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13
Q

Conc. Of nitric acid

A

5-10%

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14
Q

Routine of mst commonly used decalcifying agent

A

Nitric acid

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15
Q

Fastest decalcifying agent in the market now

A

Nitric acid

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16
Q

Nitric acid imparts a color ______ to the tissue sample through ______ formation

A

Yellow

Nitrous acid

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17
Q

What is the remedy caused by the yellow coloration of nitric acid

A

Add urea or sodium thiosulfate/ sulfate

70% ROH

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18
Q

Variations of nitric acid

A

10% aqueous nitric acid solution

Formol nitric acid

Perenyis fluid

Phloroglucinol-Nitric acid

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19
Q

Primarily used as surface decalcification

A

2% HCl

20
Q

Components of perenyi’s fluid

A

Nitric acid + chromic acid + ROH

21
Q

Fastest decalcifying agent

A

Phloroglucinol-Nitric Acid

22
Q

Provides good nuclear staining at 1%

A

HCl

23
Q

Lower and causes more distortion than nitric acid

A

HCl

24
Q

Von ebner’s fluid is what type of acid

A

HCl

25
Q

Decalcifying agent used for teeth and small bones

A

HCl

Von ebner’s fluid

26
Q

Component of von ebner’s fluid

A

HCl + 36% NaCl + distiled water

27
Q

Good for routine decalcification of post-mortem research tissues, small pieces of teeth and bone, ISH staining

A

Formic Acid

28
Q

If the formic acid contains a large amount of_____, it produces better nuclear staining and less tissue distortion

A

nitric acid

29
Q

Best for small bone spicules

Good nuclear staining

Slow, weak

A

Trichloroacetic acid

30
Q

Best for minute bone spicules

A

Chromic acid

31
Q

Chromic acid is also known as

A

Flemming’s fluid

32
Q

Best for minute pieces of bone

Weak

A

Sulfurous acid

33
Q

Ph of citric acid citrate buffered solution

A

4.5

34
Q

principle of chelating agents

Use of other ____ to form complexes with _____ for ease of removal

A

Salts

Calcium salts

35
Q

Chelating agents are utilized in ________ and _______ with the help of electron microscope

A

Immunohistochemistry

Enzyme stainig

36
Q

Duration for chelating agents

Small tissue sample
Longer and dense bones

A

1-3 weeks
6-8 weeks

37
Q

Ph of chelating agents

A

7-7.4

38
Q

Common brand of chelating agent

A

CalEx and Versene

Contains Na2EDTA

39
Q

Principle of ION EXCHANGE RESIN

Increase_____

Uses formic acid with TSE :_________ (ratio)

A

solubility

Formic acid of 1:20-30

40
Q

Remove calcium ions from formic acid containing
decalcifying solutions

Not recommended for hydrochloric acid and nitric acid fluid containing mineral acids

A

ION EXCHANGE RESIN

41
Q

ION EXCHANGE RESIN

Decalcification Extent:
Can be measured using physical method by simply _______the tissue sample and/or______

A

bending or poking

X-ray method

42
Q

Principle OF ELECTROPHORESIS

• Attracting______ going to the cathode part of the____

A

calcium ions

agarose gel

43
Q

Advantage of Electrophoresis

A

Time is shortened due to heat and electrolytic reaction produced in the process

44
Q

T or F

Electrophoresis is used for large bones

A

False

45
Q

Electrophresis

Decalcification Extent:
Best Measured Using:

A

• Physical or Mechanical Test
• X-ray or Radiologic Method
• Chemical Method