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Hpct > FAULTS IN TISSUE PROCESSING AND SECTIONING > Flashcards

FAULTS IN TISSUE PROCESSING AND SECTIONING Flashcards

1
Q

reason of brittle and hard tissue

A

prolonged fixation
prolonged dehydration
prolonged clearing
prolonged paraffin infiltration in overheated paraffin oven
drying out of tissue before actual fixation
failure to give special handling of tissues when treated with routine processing methods

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2
Q

remedy in brittle and hard tissue

A

Tissues may be softened by soaking in a small dish or bowl containing water with detergent, phenol or Molliflex.

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3
Q

causes of clearing agent turns milky as soon as tissue is placed on it

A

water not completely removed due to incomplete dehydration

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4
Q

remedy for the clearing agent that turns milky as soon as tissue is placed in it

A

Repeat dehydration with absolute alcohol, then clear again

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5
Q

give the reason

On trimming, tissue smells of clearing agent

A

Clearing agent not completely removed due to insufficient impregnation

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6
Q

give the remedy

tissue smells of clearing agent

A

Block is trimmed down nearest to the tissue, remaining wax is melted on embedding oven and paraffin impregnation is repeated, changing the paraffin at least once before blocking

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7
Q

give the reason

Tissue is opaque, section–cutting is difficult due to presence of alcohol

A

Insufficient clearing

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8
Q

give the remedy

Tissue is opaque, section–cutting is difficult due to presence of alcohol

A

Repeat clearing; if object has already been embedded, prolong clearing up to 12 hours then re–embed

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9
Q

reason for

Tissue shrinks away from wax when trimmed

A

Insufficient dehydration, therefore incomplete clearing and impregnation

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10
Q

remedy

Tissue shrinks away from wax when trimmed

A

repeat the whole procedure

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11
Q

reason

Tissue is soft when block is trimmed

A

incomplete fixation

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12
Q

remedy for

Tissue is soft when block is trimmed \

A

repeat fixation

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13
Q

reason for
Airholes found on tissue during trimming

A

incomplete impregnation

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14
Q

remedy for
Airholes found on tissue during trimming

A

repeat impregnation

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15
Q

reason for

On trimming, wax appears crystalline

A

contaminated wax

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16
Q

remedy for

On trimming, wax appears crystalline

A

re-embed in freshly filtered wax

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17
Q

reason for

Paraffin block after cooling is moist and crumbles

A

insufficient impregnation

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18
Q

remedy for

Paraffin block after cooling is moist and crumbles

A

repeat paraffin impregnation then re-embed

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19
Q

what are the faults in tissue processing

A

brittle or hard tissue
clearing agent turns milky as soon as tissue is placed in it
on trimming, tissue smells clearing agent
tissue is opaque, section-cutting is difficult due to presence of alcohol
tissue shrinks away from wax when trimmed
tissue is soft when block is trimmed
airholes found on tissue during trimming
on trimming, wax appears crystalline
paraffin block after cooling is moist and crumbles

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20
Q

reason

sections are too thick

A

wrong micrometer setting

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21
Q

remedy if the sections are too thick

A

microtome needs recalibration

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22
Q

give the reason
sections fall to form ribbons

A

surfaces and edges of the block are not parallel
horizontal surface of the block is not parallel to the knife
paraffin wax is too hard
knife is tilted too much
sections are too thick
knife is dull

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23
Q

give the reason if the sections roll up on cutting so that they adhere and get broken against the knife edge

A

knife is blunt
tilt of knife is too great
knife edge is dirty

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24
Q

remedy if the sections roll up on cutting so that they adhere and get broken against the knife edge

A

sharpen the knife
reduce the tilt
clean the knife edge

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25
Q

sections fall to form ribbons

reason: Surfaces and edges of the block are not parallel

remedy:

A

re trim the block

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26
Q

sections fall to form ribbons

reason: horizontal surface of the block is not parallel to the knife

remedy:

A

re adjust and re orient the block

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27
Q

sections fall to form ribbons

reason: paraffin wax is too hard
remedy:

A

coat horizontal edges of the block with wax of lower melting point

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28
Q

sections fall to form ribbons

reason: knife is tilted too much
remedy:

A

reduce the tilt

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29
Q

sections fall to form ribbons

reason: section that are too thick
remedy:

A

readjust the thickness of the sections

30
Q

sections fall to form ribbons

reason: dull knife
remedy:

A

hone and strop

31
Q

give the reason

ribbon is curved, crooked, or uneven, instead of straight

A

blunt or dull spot on the knife producing an irregular knife edge

edges of the block are not parallel nut round or wedge shaped

knife is not parallel to the block

32
Q

ribbon is curved, crooked, or uneve, instead of straight

reason : ribbon is curved, crooked, or uneven, instead of straight

remedy :

A

adjust the knife so that knife edge will present a uniformly sharp edge to the black or sharpen it

33
Q

ribbon is curved, crooked, or uneve, instead of straight

reason : edges of the block are not parallel but round or wedge shaped

remedy :

A

retrim the block

34
Q

ribbon is curved, crooked, or uneve, instead of straight

reason : knife is not parallel to the block

remedy :

A

readjust the knife and block

35
Q

reason why the sections turned compressed, wrinkled, or jammed

A

knife is blunt or dull
paraffin block is warm and soft
knife edge is coated with paraffin
sections are too thin
microtome set screw loose
tilt or knife is vertical

36
Q

sections turned compressed, wrinkled, or jammed

reason: knife is blunt or dull
remedy:

A

resharpen the knife

37
Q

sections turned compressed, wrinkled, or jammed

reason: paraffin block is warm and soft
remedy:

A

cool the block on ice water until firm

38
Q

sections turned compressed, wrinkled, or jammed

reason: knife edge is coated with paraffin
remedy:

A

clean the knife edge

39
Q

sections turned compressed, wrinkled, or jammed

reason: sections are too thin
remedy:

A

re adjust thickness of the section

40
Q

sections turned compressed, wrinkled, or jammed

reason: microtome set screw is loose
remedy:

A

tighten the scree

41
Q

sections turned compressed, wrinkled, or jammed

reason: tilt of knife is too vertical
remedy:

A

reduce the tilt

42
Q

reason why the sections turned squashed (width of each section is less than of the block)

A

bevel knife is lost due to incorrect sharpening

43
Q

remedy for the sections that turned squashed (width of each section is less than of the block)

A

re sharpen using knife back or automatic knife sharpener

44
Q

reason why there’s a hole formed in the section

A

bubble or dirt formed in the embedding medium
tissue is not processed properly and will not form a section
under-processed portion of tissue bursts on contact with warm water
hard spot in tissue due to calcium

45
Q

A hole is formed in
the section

reason: bubble or dirt formed in the embedding medium
remedy

A

re embed in freshlt filtered wax if necessary

46
Q

A hole is formed in
the section

reason: tissue is not processed properly and will not form a section
remedy :

A

re process tissue

47
Q

A hole is formed in
the section

reason: under processed portion of tissue bursts on contact with warm water
remedy:

A

re process tissue

48
Q

A hole is formed in
the section

reason: hard spot in tissue due to calcium
remedy :

A

once embedded in paraffin wax, decalcification is impractical; use a base-sledge microtome with a wedge knife

49
Q

reason for section of unequal thickness are produced

A

tilt of knife is too great or bevel is not cleared, hence object is compressed against the knife edge

clamp set screw on knife or block holder is loose

blocks are too large

blocks are too hard

50
Q

reason for section of unequal thickness are produced

reason: tilt of knife is too great or bevel is not cleared, hence object is compressed against the knife edge
remedy:

A

reduce the tilt

51
Q

reason for section of unequal thickness are produced

reason: clamp set screw on knife or block holder is loose

remedy:

A

tighten the screw

52
Q

reason for section of unequal thickness are produced

reason: blocks are too large

remedy:

A

cut blocks into smaller fragments

53
Q

reason for section of unequal thickness are produced

reason: blocks are too large

remedy:

A

cut blocks into smaller fragments

54
Q

reason for section of unequal thickness are produced

reason: blocks are too hard
remedy:

A

soften the blocks in detergent or phenol

55
Q

reason why
sections adhere to the knife or other parts of the microtome

A

static electricity due to low atmospheric humidity

knife edge is dirty

knife edge is dull

knife till is too great

56
Q

Sections adhere to the
knife or other parts of
the microtome

reason: static electricity due to low atmospheric humidity

remedy:

A

breathe out or blow gently on the block and knife to break up static electricity, or boil water in the room to increase humidity

57
Q

reason for ribbon split or lengthwise vertical scratches seen on sections

A

nicks or damage on the knife edge
dirty embedding
knife edge is dirty
tilt of knife too great

58
Q

ribbon split or lengthwise vertical scratches seen on sections

reason: nicks or damage on the knfe edge

remedy:

A

sharpen the knife

59
Q

ribbon split or lengthwise vertical scratches seen on sections

reason: dirty embedding

remedy:

A

re-embed in freshly filtered wax

60
Q

ribbon split or lengthwise vertical scratches seen on sections

reason: dirty knife edge

remedy:

A

clean with xylene

61
Q

ribbon split or lengthwise vertical scratches seen on sections

reason: tilt of knife too great

remedy:

A

reduce the tilt

62
Q

reasons for sections are lifted from the knife on upstrokes

A

knife tilt is too great
knife is dull
paraffin is too soft or room temperature is warm

63
Q

reasons for sections are lifted from the knife on upstrokes

reason: parafin is too sofy or room temperature is warm

remedy:

A

cool paraffin wax in ice water

64
Q

reason for the resistance felt on the lower part of the section during cutting

A

tilt of knife is too small,
paraffin block is therefore compressed against the based of the knife towards the end of the stroke

65
Q

remedy for the resistance felt on the lower part of the section during cutting

A

increase the tilt of the knife

66
Q

reasons why there’s horizontal or parallel lines or furrows across the section (chatters) are seen

A

knife edge vibrations due to hardness of tissue
tilt of knife is too great

67
Q

remedy for knife edge vibrations due to hardness of tissue

A

treat with phenol during processing or collodioniz

68
Q

reason for

Section cut is
sometimes thin,
sometimes thick

A

knife is blunt
knife is not clamped properly
knife or block holder is loose
knife tilt is too small that block is compressed by bevel and section is not cut

69
Q

reason

Knife makes a hard
metallic scraping or
ringing sound on
backstroke, when
section is cut

A

tilt of knife is too slanted or too big
tissue is too hard
knife is too thin

70
Q

reason why Frozen tissue
crumbles and comes
off the block holder
when cut

A

freezintg is not adequate

71
Q

Frozen tissue chips
into fragments when
cut

A

tissue is frozen too much

72
Q
A

Hpct (18 decks)

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