Microtomy

Question 1

how does a rotary microtome work

Answer 1

moving the block over a stationary blade and advancing the block each cycle

Question 2

why is tissue cut 4-5um

Answer 2

single layer of cells

Question 3

what tissues are cut 2-3um

Answer 3

lymph and kidney

Question 4

what tissues are cut 6-8um

Answer 4

breast and brain

Question 5

what are disposable blades not sharp enough to cut. what is used instead?

Answer 5

resin embedded blocks use glass or diamond to cut <1um

Question 6

What is facing

Answer 6

trimming away excess wax to expose the full face of tissue

Question 7

how long does the block have to cool for

Answer 7

at least 15 minutes

Question 8

what is levelling

Answer 8

section is made, then trim 60-100 um and another section is made

Question 9

what is serial sections

Answer 9

block is faced and every ribbon is put on slide without skipping sections

Question 10

what are deepers or recuts from a pathologist

Answer 10

levels are made

Question 11

what steps for microtomy

Answer 11

1. locate safety mechanism
2. adjust microtome setting
3. ensure all levers are tight
4. patient soaking the block
5. short ribbons are fine
6. keep it clean

Question 12

when should the handwheel be locked

Answer 12

inserting/removing a block and not actively cutting

Question 13

what are the microns for facing

Answer 13

20-30

Question 14

what steps are done prior to fine cutting

Answer 14

fixaation
processing
microtome
temperature of block is softened

Question 15

what steps happen during fine cutting

Answer 15

cutting speed = 1 rotation per second

ribbons

water bath = 10 degrees below MP of wax

section retrieval

Question 16

Causes of curved sections

Answer 16

block edge not parallel
dull blade
ununiform tissue density

Question 17

solution to curved sections

Answer 17

face until parallel
new blade

Question 18

causes of chatter

Answer 18

loose lever vibration
high clearance angle
hard tissue
OVERDEHYDRATED tissue
dull blade

Question 19

solutions to chatter

Answer 19

tighten levels
lower clearance angle
surface decal/ rehydrate tissue
new blade

Question 20

causes of holes in section

Answer 20

facing aggressively
hard particles in the tissue

Question 21

solution of holes in section

Answer 21

lower micrometer setting
soak block in water

Question 22

section splitting perpendicular to blade

Answer 22

nick in blade
calcification
hard particles

Question 23

solution to splitting perpendicular to blade

Answer 23

new blade
surface decal
reembed

Question 24

fail to form ribbons causes

Answer 24

too hard wax
wrong clearance angle

Question 25

solution to failing form of ribbons

Answer 25

warm the block with thumb increase speed adjust clearance angle

Question 26

sections attach to block on return stroke causes

Answer 26

low clearance angle debris microtome retraction now working STATIC ELECTRICITY

Question 27

solution to section attaching to block

Answer 27

increase clearance angle HUMIDIFY the room

Question 28

causes of incomplete sections

Answer 28

not fully faced incomplete paraffin infiltration

Question 29

solution to incomplete sections

Answer 29

reface block reembed or reprocess

Question 30

causes of compression

Answer 30

dull blade soft or warm paraffin

Question 31

solution to compression

Answer 31

new blade cool block reembed in harder wax

Question 32

causes of expanding section in waterbath

Answer 32

incomplete tissue high water bath temp

Question 33

soluition to expansion in waterbath

Answer 33

reprocess decrease water bath temp

Question 34

causes of section rolling into cylinder instead of flat

Answer 34

dull blade too thick sections

Question 35

solution to rolling sections

Answer 35

new blade thinner sections

Question 36

what temperature is the water bath

Answer 36

41-45 degrees or 10 degrees lower than MP of wax

Question 37

too cold waterbath causes what to sections

Answer 37

wrinkles not come out

Question 38

warm waterbath will cause what to section

Answer 38

melt and disintegrate section

Question 39

how long and temperature of the oven

Answer 39

30 min - 1 hr at <60C usually 37C

Question 40

what is a disadvantage of using microwaves to dry slides

Answer 40

cooking the water and fat of the tissue

Question 41

purpose of the oven

Answer 41

remove any water from section NOT MELT WAX

Question 42

what happens if water is on the slides when staining

Answer 42

deparrifinization is incomplete

Question 43

when are adhesive or charged slides used

Answer 43

when slides undergo harsh solutions or pretreatments during staining eg silver stains or IHC (moisture and enzymes)

Question 44

what are common adhesives

Answer 44

gelatin albumin elmers glue poly L lysine

Question 45

disadvantage of adhesives

Answer 45

produce background saining

Question 46

T/F charge slides are positively charged

Answer 46

T

Question 47

what method to make charge slides

Answer 47

3-aminopropyltriethoxysilane (APTES)

Question 48

how does APTES work

Answer 48

covalent bind to glass making an amino group coating

Question 49

causes of parched earth

Answer 49

improper processing tissue chilled too rapidly (cryosprays) floating on waterbath too long