FAULTS IN TISSUE PROCESSING AND SECTIONING

Question 1

reason of brittle and hard tissue

Answer 1

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

Question 2

remedy in brittle and hard tissue

Answer 2

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

Question 3

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

Answer 3

water not completely removed due to incomplete dehydration

Question 4

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

Answer 4

Repeat dehydration with absolute alcohol, then clear again

Question 5

give the reason

On trimming, tissue smells of clearing agent

Answer 5

Clearing agent not completely removed due to insufficient impregnation

Question 6

give the remedy

tissue smells of clearing agent

Answer 6

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

Question 7

give the reason

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

Answer 7

Insufficient clearing

Question 8

give the remedy

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

Answer 8

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

Question 9

reason for

Tissue shrinks away from wax when trimmed

Answer 9

Insufficient dehydration, therefore incomplete clearing and impregnation

Question 10

remedy

Tissue shrinks away from wax when trimmed

Answer 10

repeat the whole procedure

Question 11

reason

Tissue is soft when block is trimmed

Answer 11

incomplete fixation

Question 12

remedy for

Tissue is soft when block is trimmed \

Answer 12

repeat fixation

Question 13

reason for
Airholes found on tissue during trimming

Answer 13

incomplete impregnation

Question 14

remedy for
Airholes found on tissue during trimming

Answer 14

repeat impregnation

Question 15

reason for

On trimming, wax appears crystalline

Answer 15

contaminated wax

Question 16

remedy for

On trimming, wax appears crystalline

Answer 16

re-embed in freshly filtered wax

Question 17

reason for

Paraffin block after cooling is moist and crumbles

Answer 17

insufficient impregnation

Question 18

remedy for

Paraffin block after cooling is moist and crumbles

Answer 18

repeat paraffin impregnation then re-embed

Question 19

what are the faults in tissue processing

Answer 19

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

Question 20

reason

sections are too thick

Answer 20

wrong micrometer setting

Question 21

remedy if the sections are too thick

Answer 21

microtome needs recalibration

Question 22

give the reason
sections fall to form ribbons

Answer 22

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

Question 23

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

Answer 23

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

Question 24

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

Answer 24

sharpen the knife
reduce the tilt
clean the knife edge

Question 25

sections fall to form ribbons reason: Surfaces and edges of the block are not parallel remedy:

Answer 25

re trim the block

Question 26

sections fall to form ribbons reason: horizontal surface of the block is not parallel to the knife remedy:

Answer 26

re adjust and re orient the block

Question 27

sections fall to form ribbons reason: paraffin wax is too hard remedy:

Answer 27

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

Question 28

sections fall to form ribbons reason: knife is tilted too much remedy:

Answer 28

reduce the tilt

Question 29

sections fall to form ribbons reason: section that are too thick remedy:

Answer 29

readjust the thickness of the sections

Question 30

sections fall to form ribbons reason: dull knife remedy:

Answer 30

hone and strop

Question 31

give the reason ribbon is curved, crooked, or uneven, instead of straight

Answer 31

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

Question 32

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

Answer 32

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

Question 33

ribbon is curved, crooked, or uneve, instead of straight reason : edges of the block are not parallel but round or wedge shaped remedy :

Answer 33

retrim the block

Question 34

ribbon is curved, crooked, or uneve, instead of straight reason : knife is not parallel to the block remedy :

Answer 34

readjust the knife and block

Question 35

reason why the sections turned compressed, wrinkled, or jammed

Answer 35

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

Question 36

sections turned compressed, wrinkled, or jammed reason: knife is blunt or dull remedy:

Answer 36

resharpen the knife

Question 37

sections turned compressed, wrinkled, or jammed reason: paraffin block is warm and soft remedy:

Answer 37

cool the block on ice water until firm

Question 38

sections turned compressed, wrinkled, or jammed reason: knife edge is coated with paraffin remedy:

Answer 38

clean the knife edge

Question 39

sections turned compressed, wrinkled, or jammed reason: sections are too thin remedy:

Answer 39

re adjust thickness of the section

Question 40

sections turned compressed, wrinkled, or jammed reason: microtome set screw is loose remedy:

Answer 40

tighten the scree

Question 41

sections turned compressed, wrinkled, or jammed reason: tilt of knife is too vertical remedy:

Answer 41

reduce the tilt

Question 42

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

Answer 42

bevel knife is lost due to incorrect sharpening

Question 43

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

Answer 43

re sharpen using knife back or automatic knife sharpener

Question 44

reason why there's a hole formed in the section

Answer 44

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

Question 45

A hole is formed in the section reason: bubble or dirt formed in the embedding medium remedy

Answer 45

re embed in freshlt filtered wax if necessary

Question 46

A hole is formed in the section reason: tissue is not processed properly and will not form a section remedy :

Answer 46

re process tissue

Question 47

A hole is formed in the section reason: under processed portion of tissue bursts on contact with warm water remedy:

Answer 47

re process tissue

Question 48

A hole is formed in the section reason: hard spot in tissue due to calcium remedy :

Answer 48

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

Question 49

reason for section of unequal thickness are produced

Answer 49

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

Question 50

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:

Answer 50

reduce the tilt

Question 51

reason for section of unequal thickness are produced reason: clamp set screw on knife or block holder is loose remedy:

Answer 51

tighten the screw

Question 52

reason for section of unequal thickness are produced reason: blocks are too large remedy:

Answer 52

cut blocks into smaller fragments

Question 53

reason for section of unequal thickness are produced reason: blocks are too large remedy:

Answer 53

cut blocks into smaller fragments

Question 54

reason for section of unequal thickness are produced reason: blocks are too hard remedy:

Answer 54

soften the blocks in detergent or phenol

Question 55

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

Answer 55

static electricity due to low atmospheric humidity knife edge is dirty knife edge is dull knife till is too great

Question 56

Sections adhere to the knife or other parts of the microtome reason: static electricity due to low atmospheric humidity remedy:

Answer 56

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

Question 57

reason for ribbon split or lengthwise vertical scratches seen on sections

Answer 57

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

Question 58

ribbon split or lengthwise vertical scratches seen on sections reason: nicks or damage on the knfe edge remedy:

Answer 58

sharpen the knife

Question 59

ribbon split or lengthwise vertical scratches seen on sections reason: dirty embedding remedy:

Answer 59

re-embed in freshly filtered wax

Question 60

ribbon split or lengthwise vertical scratches seen on sections reason: dirty knife edge remedy:

Answer 60

clean with xylene

Question 61

ribbon split or lengthwise vertical scratches seen on sections reason: tilt of knife too great remedy:

Answer 61

reduce the tilt

Question 62

reasons for sections are lifted from the knife on upstrokes

Answer 62

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

Question 63

reasons for sections are lifted from the knife on upstrokes reason: parafin is too sofy or room temperature is warm remedy:

Answer 63

cool paraffin wax in ice water

Question 64

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

Answer 64

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

Question 65

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

Answer 65

increase the tilt of the knife

Question 66

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

Answer 66

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

Question 67

remedy for knife edge vibrations due to hardness of tissue

Answer 67

treat with phenol during processing or collodioniz

Question 68

reason for Section cut is sometimes thin, sometimes thick

Answer 68

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

Question 69

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

Answer 69

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

Question 70

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

Answer 70

freezintg is not adequate

Question 71

Frozen tissue chips into fragments when cut

Answer 71

tissue is frozen too much