TISSUE PROCESSING Flashcards

1
Q
  • optional step
  • decalcification is needed
  • Bones, teeth, calcified specimens
  • Process whereby calcium or lime salts are removed from tissues, following fixation
A

DECALCIFICATION

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2
Q

Acid decalcifying agents?

A
  1. nitric acid
  2. hydrochloric acid
  3. formic acid
  4. trichloroacetic acid
  5. sulfurous acid
  6. chromic acid
  7. citric acid
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3
Q

Histopathologic techniques

A
  1. numbering
  2. fixation
    [decalcification]
  3. dehydration
  4. clearing
  5. wax impregmentation
  6. embedding
  7. blocking
  8. trimming
  9. sectioning
  10. staining
  11. mounting
  12. labelling
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4
Q

6 main factors involved in fixation?

A
  1. hydrogen ion concentration
  2. temperature
  3. tissue section thickness
  4. osmolality
  5. concentration of fixative
  6. duration of fixation
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5
Q

hydrogen ion concentrations should be ph of ____ to be satisfactory

A

6-8

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6
Q

temperature of fixatives in manual methods is?

A

room temperature

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7
Q

the ideal size for light microscopy in fixatives of tissue section thickness is

A

2 cm^2

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8
Q

osmolality should be ____ so that it cannot alter the morphology of the cell…

A

slightly hypertonic [400-450 mOsm]

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9
Q

concentration of fixative is?

A

low

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10
Q

duration of fixation is ____ hrs. once specimen is received…

commonly used reagent/chemical in duration of fixation?

A

2-6

Neutral buffered formalin

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11
Q

Types of Aldehyde Fixatives:

A
  1. formaldehyde [formalin]
  2. 10% formol saline
  3. 10% neutral buffered formalin
  4. formol corrosive [formol sublimate]
  5. glutaraldehyde
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12
Q
  • commercially available as 40% PURE STOCK SOLUTION
  • pure stock solution are not ideal for routine fixation
  • commonly used @ 4% solution, making a 10% formalin for fixation
A

Formaldehyde [formalin]

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13
Q

advantages of formaldehyde?

A
  • cheap
  • readily available
  • stable [no storage requirement]
  • easy to prepare
  • compatible w/ many routine stains
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14
Q

disadvantages of formaldehyde?

A
  • irritating fumes
  • produce shrinkage if prolonged fixation occurs
  • produce quality of cytologic staining if unbuffered
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15
Q
  • Saturated Formaldehyde diluted to 10% with sodium chloride
  • Common diluent used: distilled water
A

10% formol saline

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16
Q
  • saturated formaldehyde diluted to 10% & buffered w/ sodium dihydrogen phosphate & disodium hydrogen phosphate
  • Common diluent used: distilled water
  • Buffering a solution makes sure that it will reduce shrinkage from happening
A

10% neutral buffered formalin

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17
Q
  • saturated formaldehyde diluted to 10% using saturated aqeous mercuric chloride [makes this fixative acidic]
A

formol corrosive [formol sublimate]

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18
Q
  • Made up of two formaldehyde residues linked by three carbon chains
    1. ____ solution for small tissues & needle biopsies [2-4 hrs]
    2. ____ solution for large tissues (less than 4 mm thick) [6-8 hrs]
A

Glutaraldehyde
1. 2.5%
2. 4%

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19
Q

advantages of glutaraldehyde:

A
  • more stable effect on tissues
  • preserves plasma proteins
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20
Q

disadvantages of glutaraldehyde:

A
  • more expensive
  • less stable as a reagent
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21
Q
  • Most common metallic fixative (Aq. Solution 5-7%)
  • Used as a secondary fixative
  • Included with many compound fixatives
  • Mercury deposits are removed before staining (0.5% iodine solution in 70% ethanol for 5-10 mins)

component of mixture used to reduce detrimental effect of this fixative.

A

Mercuric chloride

Glacial acetic acid

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22
Q

Advantages of Mercuric chloride:

A
  • Nuclear components are shown in
    fine detail
23
Q

Disadvantages of Mercuric chloride

A
  • Causes marked shrinkage of cells
  • Cause precipitation of cells; mercury that will cause confusion in microscopy
24
Q

Example of Chromate fixatives?

A
  1. chromic acid
  2. potassium dichromate
25
Q
  • 1-2% Aqueous Solution
  • Used as a component in compound fixatives
A

Chromic Acid

26
Q
  • 3% Aqueous solution
  • Preserves lipids
  • In formalin or formaldehyde, lipids are not preserved well
A

Potassium Dichromate

27
Q

Alcohol dehydrating agents?

A
  1. ethanol
  2. methyl alcohol
  3. butyl alcohol
28
Q
  • Recommended for routine dehydration of tissues
  • “best dehydrating agent”
  • works the fastest & the least hazardous
A

Ethanol

29
Q

Used for blood and tissue films for smear preparations

A

Methyl Alcohol

30
Q
  • For plant and animal micro-techniques
  • works the slowest
A

Butyl alcohol

31
Q

Starting point ng babaran sa alcohol?

A

70-75%

32
Q

Common clearing agents?

A
  • Xylene
  • Toluene
33
Q
  • Most commonly used as a clearing agent (1/2-1 hr)
  • Ideally used on tissue blocks with less than 5 mm thickness
A

Xylene

34
Q

Advantages of Xylene?

A
  • most rapid clearing agents
  • miscible w/ alcohol & paraffin wax
  • cheap
35
Q

Disadvantages of xylene?

A
  • Makes tissues excessively hard and brittle if used for long periods (>3 hrs)
  • Not suitable for nervous tissues and lymph nodes
36
Q

clearing agent used for nervous tissues & lymph nodes?

A

chloroform

37
Q
  • 1-2 hours clearing time
  • Suitable substitute for xylene or benzene

benzene - clearing agent but more toxic

A

Toluene

38
Q

Advantages of toluene?

A
  • Tissues do not become excessively hard or brittle
  • Not carcinogenic
39
Q

Disadvantages of toluene?

A
  • More expensive
  • Reacts relatively slower than xylene or benzene
40
Q

Melts at 54-58 C (Laboratory temperature must be taken in consideration)

A

Paraffin wax

41
Q

Advantages of Paraffin wax?

A
  • Individual sections of the tissue block may be cut with ease
  • Allows for rapid process (24 hrs)
  • Tissue blocks may be stored immediately
42
Q

Disdvantages of Paraffin wax?

A
  • Overheated paraffin makes specimen brittle
  • Prolonged impregnation causes shrinkage of cells
  • Not recommended for fatty tissues
43
Q
  • Utilizes micro-anatomical studies of tissue
  • It is a regressive staining method
A

HAEMATOXYLIN AND EOSIN STAINING

44
Q

is used to stain nuclear components

A

Haematoxylin

45
Q

used for cytoplasmic components

A

Eosin

46
Q

Nuclei?

A

blue to black

47
Q

Karyosome?

A

dark blue

48
Q

Karyosome?

A

dark blue

49
Q

Cytoplasm?

A

light pink

50
Q

Cartilage?

A

pale pink

51
Q

Calcified bone?

A

purplish blue

52
Q

Decalcified bone matrix, collagen, and osteoid?

A

pink

53
Q

muscle fibers?

A

deep pink