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Histopathologic & Cytologic Techniques (Lecture) > Chapter 8 > Flashcards

Chapter 8 Flashcards

1
Q

the removal of calcium ions or lime salts from the organic extracellular matrix, calcified collagen, and surrounding tissues of the bone.

A

bone decalcification

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2
Q

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

A

decalcification

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3
Q

Decalcification enables the histotechnologist to cut soft sections of the bone using the _______, so that they can be processed like any other soft tissue of the body

A

microtome

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4
Q

Decalcification is a lengthy procedure, as bone pieces have to be left in the decalcifying agent for
______ or _______, depending on the size of the tissue

A

several days or even weeks

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5
Q

thickness of specimen

A

2-3mm

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6
Q

a satisfactory fixative for bone
but where the preservation of bone marrow is important

A

buffered formalin

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7
Q

3 main types of decalcifying agents

A

strong mineral acids
weaker organic acids
chelating agents

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8
Q

the most widely used agents for routine decalcification of large amounts of bony tissues because they are stable, readily
available, and relatively inexpensive as compared to other decalcifying agents

A

acid decalcifying agents

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9
Q

the most rapid in action but if used longer than necessary will rapidly cause a loss of nuclear staining and can macerate tissues

A

strong acids (hydrochloric or nitric acid)

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10
Q

concentrations of strong acids (hydrochloric or nitric acid)

A

up to 10%

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11
Q

The most common and the fastest decalcifying agent used so far, utilized both as a simple solution
or combined with other reagents.

A

nitric acid

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12
Q

This may be used as simple aqueous solutions with recommended concentrations of 5-10%.

A

nitric acid

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13
Q

It is a very rapid decalcifying agent, producing minimal distortion and is, therefore, recommended for routine purposes

A

nitric acid

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14
Q

The disadvantages are inhibiting nuclear stains and destroying tissues, especially in concentrated solutions

A

nitric acid

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15
Q

Nitric acid should be prevented by not combining it with ______ or ______

A

formaldehyde or alcohol

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16
Q

FORMULA:
○ Concentrated nitric acid 10 mL
○ Distilled water added up to 100 mL

A

aqueous nitric acid solution (10%)

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17
Q

decalcification time of aqueous nitric acid solution (10%)

A

12-24 hours

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18
Q

ADVANTAGES:
- It is rapid in action
- It produces minimum distortion of tissues
- It produces good nuclear staining (although less than in slower acting agents)
- The acid may be easily removed by 70% alcohol
- It is recommended for urgent biopsy, and for needle and small biopsy specimens to permit rapid diagnosis within 24 hours or less
- It can be used for large or heavily mineralized cortical bone specimen if decalcification progress is carefully monitored by a decalcification endpoint test

A

aqueous nitric acid solution (10%)

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19
Q

DISADVANTAGES:
-Prolonged decalcification may lead to tissue distortion
-It can seriously damage tissue stainability
- It imparts a yellow color with nitrous acid, thereby impairing the staining reaction of the tissue
- Old nitric acid solution is particularly damaging and should be replaced with fresh stock solution
- Strong acids tend to be more damaging to tissue antigens for immunohistochemical staining, and enzymes may be totally lost

A

aqueous nitric acid solution (10%)

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20
Q

FORMULA:
○ Concentrated nitric acid 10 mL
○ Strong formaldehyde, 40% 5 mL
○ Distilled water 85 mL

A

formol-nitric acid

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21
Q

decalcification time for formol-nitric acid

A

1-3 days

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22
Q

Advantages:
- It is rapid-acting; hence, is recommended for urgent biopsies
- Nuclear staining is relatively good
- It produces less tissue destruction than 10% aqueous nitric acid

A

formol-nitric acid

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23
Q

DISADVANTAGE:
The yellow color imparted by nitrous acid formation will impair staining reaction of the cell.

A

formol-nitric acid

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24
Q

FORMULA:
○ Nitric acid 10% 40 mL
○ Chromic acid 0.5% 30 mL
○ Absolute ethyl alcohol 30 mL

A

perenyi’s fluid

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25
Q

Mix shortly before use. Chromic acid must be collected for proper disposal.

A

perenyi’s fluid

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26
Q

decalcification time for perenyi’s fluid

A

2-7 days

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27
Q

ADVANTAGES:
- It is recommended for routine purposes
- It decalcifies and softens tissues at the same time
- Nuclear and cytoplasmic staining is good
- Maceration is avoided due to the presence of chromic acid and alcohol

A

perenyi’s fluid

28
Q

DISADVANTAGE:
It is a slow decalcifying agent for dense bones; hence, is not recommended for urgent diagnosis

A

perenyi’s fluid

29
Q

FORMULA:
○ Concentrated nitric acid 10 mL
○ Phloroglucin 1g
○ Nitric acid 10% 100 mL

A

phloroglucin-nitric acid

30
Q

(To be added after disappearance of dense white fumes formed by combining the first two ingredients.)

A

phloroglucin-nitric acid

31
Q

decalcification time for phloroglucin-nitric acid

A

12-24 hours

32
Q

ADVANTAGE:
It is the most rapid decalcifying agent so far, recommended for urgent cases

A

phloroglucin-nitric acid

33
Q

DISADVANTAGES:
- Nuclear staining is poor
- Prolonged decalcification produces extreme tissue distortion
- Yellow color must be neutralized with 5% sodium sulfate and thoroughly washed with running tap water for at least 24 hours

A

phloroglucin-nitric acid

34
Q

inferior compared to nitric acid in its role as a decalcifying agent because of its slower action and greater distortion of tissue
produced on the decalcified section.

A

hydrochloric acid (HCl)

35
Q

hydrochloric acid (HCl) produces good nuclear staining and if used in _________, may be recommended for surface decalcification of the tissue blocks

A

1% solution with 70% alcohol

36
Q

FORMULA:
○ Saturated aqueous solution of NaCl 50 mL
○ 36% concentrated hydrochloric acid 8 mL
○ Distilled water 50 mL

A

von ebner’s fluid

37
Q

ADVANTAGES:
- It permits relatively good cytologic staining
- It is a moderately rapid decalcifying agent
- It does not require washing out before dehydration
- It is recommended for teeth and small pieces of bone

A

von ebner’s fluid

38
Q

DISADVANTAGE:
The extent of decalcification cannot be measured by a chemical test

A

von ebner’s fluid

39
Q

WEAK ACIDS such as ______ are popular and are widely used for decalcification

A

formic acid

40
Q

Organic acids such as ______ and ______ are better suited to bone marrow, since they are not as harsh. However, they act more slowly on dense cortical bone

A

acetic and formic acid

41
Q

Other acids such as ________ have also been used

A

trichloroacetic acid (TCA)

42
Q

_______ and _______ are not used alone as decalcifying agents, but are found as components of Carnoy’s and Bouin’s fixatives.

A

Picric acid and acetic acid

43
Q

These fixatives may act as incidental, albeit, weak decalcifiers, and can be used in urgent cases when there is only minimal calcification

A

carnoy’s and bouin’s fixatives

44
Q

a moderate-acting decalcifying agent which produces better nuclear staining with less
tissue distortion, and is safer to handle than nitric acid or hydrochloric acid

A

formic acid

45
Q

It is recommended for routine decalcification of postmortem research tissues, although not suitable for urgent examinations

A

formic acid

46
Q

Formic acid can be used as a ________ or combined with formalin or with a buffer

A

simple 10% aqueous solution

47
Q

It is slower than the strong acid agents, but it is much gentler in action and less likely to interfere with nuclear staining

A

formic acid

48
Q

______ in a 10% concentration is the best all-around decalcifier

A

formic acid

49
Q

________ is the only weak acid used extensively as a primary decalcifying agent. Addition of citrate probably accelerates decalcification by chelating the calcium as it is liberated from the bone

A

formic acid

50
Q

FORMULA:
○ Formic acid (Sp. grav. 1.20) 10 mL
○ Normal saline 10% 90 mL

A

formic acid

51
Q

decalcification time for formic acid

A

2-7 days

52
Q

It may be used both as a fixative and decalcifying agent

A

formic acid

53
Q

It requires neutralization with 5% sodium sulfate, and washing out to remove the acid from the tissue

A

formic acid

54
Q

FORMULA:
○ Aqueous sodium citrate 20% 50 mL
○ Formic acid 45% 50 mL

A

formic acid-sodium citrate solution

55
Q

decalcification time for formic acid-sodium citrate solution

A

3-14 days

56
Q

It is recommended for autopsy materials, bone marrow, cartilage and tissues studied for research purposes

A

formic acid-sodium citrate solution

57
Q

DISADVANTAGES:
- It is relatively slow; hence, is not recommended for routine purposes and for dense tissues
- It requires neutralization with 5% sodium sulfate

A

formic acid-sodium citrate solution

58
Q

FORMULA:
○ Trichloroacetic acid 5 g
○ Formal saline 10% 95 mL

A

trichloroacetic acid

59
Q

decalcification time for trichloroacetic acid

A

4-8 days

60
Q

It does not require washing out; the excess acid may be removed by several changes of 90% alcohol, thus improving tissue dehydration

A

trichloroacetic acid

61
Q

DISADVANTAGES:
- It is a weak decalcifying agent, not used for dense tissues, and is suitable only for small spicules of bone
- It is very slow-acting; hence, is not recommended for urgent examinations

A

trichloroacetic acid

62
Q

a very weak decalcifying solution suitable only for minute pieces of bone

A

sulfurous acid

63
Q

FORMULA:
○ Chromic acid % 15 mL
○ Osmium tetroxide 4 mL
○ 2% Glacial acetic acid 1 mL

A

chromic acid

64
Q

environmental toxin and is highly corrosive to skin and mucous membrane

A

chromic acid

65
Q

substances which combine with calcium ions and other salts (e.g. iron and magnesium deposits) to form weakly dissociated complexes and facilitate removal of calcium salt

A

chelating agents

66
Q

The most common chelating agent in the market is __________, with the commercial name of Versene, recommended only for detailed microscopic studies

A

EDTA salt

Histopathologic & Cytologic Techniques (Lecture) (5 decks)

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