SAS 5: Infiltration, Embedding, and Microtomy

Question 1

It is the process of completely removing the clearing agent and it will be replaced by a medium that will completely fill all the tissue cavities

Answer 1

Impregnation (Infiltration)

Question 2

This allows easier cutting and handling of tissue sections

Answer 2

Impregnation (Infiltration)

Question 3

Types of impregnating and embedding media:

Answer 3

1. Paraffin wax
2. Celloidin
3. Gelatin
4. Plastic

Question 4

It is the simplest, most common and best embedding medium used for routine tissue processing.

Answer 4

Paraffin wax

Question 5

It is a polycrystalline mixture of solid hydrocarbons produced during the refining of coal and mineral oils. It is solid at room temperature but melts at temperature up to about 65 or 70C

Answer 5

Paraffin wax

Question 6

Advantages of Paraffin Wax:

Answer 6

1. Serial sections are cut with ease and majority without undue distortion
2. Very rapid, allows sections to be prepare within 24 hours
3. Tissue blocks and unstained can be stored in paraffin for an indefinite period of time.
4. Many staining procedures are permitted
5. Nucleic acids (DNA or RNA) may be recovered from them decades after fixation

Question 7

Disadvantages of Paraffin Wax:

Answer 7

1. Overheated paraffin makes tissue brittle
2. Prolonged impregnation will cause tissue shrinkage
3. Inadequate impregnation promotes clearing agent retention
4. Tissues difficult to infiltrate need long immersion for proper support
5. Not recommended for fatty tissues

Question 8

Paraffin wax melts in ____ or an ____

Answer 8

oven or an incubator

Question 9

Melting the paraffin wax in oven or incubator should be regulated at _____

Answer 9

55-60C

Question 10

The most common waxes melting point

Answer 10

56C

Question 11

3 ways of impregnation and embedding of tissues

Answer 11

1. Manual processing
2. Automatic processing
3. Vacuum embedding

Question 12

For manual processing of impregnation, 4 changes of wax for _____ each interval

Answer 12

15 minutes

Question 13

This methos makes use of an automatic processing machine (autotechnicon)

Answer 13

Automatic processing

Question 14

Fixes, dehydrates, clears and infiltrates tissue automatically, thereby decreasing the time and labor needed during the processing of tissues

Answer 14

Automatic processing

Question 15

It change 2 to 3 wax that is required in removing the clearing agent

Answer 15

Automatic processing

Question 16

How many processing steps does the Autotechnicon have?

Answer 16

12

Question 17

How many 1-liter glass beakers does the Autotechnicon have?

Answer 17

10

Question 18

How many thermostatically wax baths does the Autotechnicon have?

Answer 18

2

Question 19

It involves wax impregnation under negative atmospheric inside an embedding oven. It reduces the time when tissues are subjected to high temperatures thus minimizing heat-induced tissue hardening

Answer 19

Vacuum processing

Question 20

It facilitates complete removal of transition solvents, and prolongs the life of wax by reducing the solvent contamination,

Answer 20

Vacuum processing

Question 21

It hastens the removal of air bubbles and clearing agent from the tissue block, thereby promoting a more rapid wax penetration of the tissue

Answer 21

Vacuum

Question 22

This technique is recommended for urgent biopsies, for delicate tissues such as lung, brain, connective tissue, bone, eye, and etc.

Answer 22

Vacuum processing

Question 23

With this technique, time is reduced by 25%-75% of the normal time required

Answer 23

Vacuum embedding/processing

Question 24

The vacuum pressure should not exceed ____

Answer 24

500 mm/hg

Question 25

Factors affecting paraffin wax impregnation:

Answer 25

1. Nature and size of the tissues 2. Type of clearing agents 3. Paraffin wax must be pure 4. Paraffin may be use twice only 5. Fixed microtomes, a relatively hard wax with a higher melting point is recommended 6. Heavier microtome knives require harder paraffin wax than lighter ones

Question 26

Paraffin must be pure and free from:

Answer 26

dust water droplets other foreign materials

Question 27

Substitutes for paraffin wax:

Answer 27

1. Paraplast 2. Ester wax 3. Water soluble waxes

Question 28

It is highly purified and synthetic plastic polymers

Answer 28

Paraplast

Question 29

More elastic and resilient than paraffin

Answer 29

Paraplast

Question 30

It is a wax that is for large dense tissue blocks like bones and brain

Answer 30

Paraplast

Question 31

It prevents ice crystals formation

Answer 31

Paraplast

Question 32

It is soluble in common clearing agents, no deposits after staining, and has the same time schedule like paraffin

Answer 32

Paraplast

Question 33

It is a semisynthetic wax recommended for embedding eyes

Answer 33

Bioloid

Question 34

It is the product of paraffin, containing rubber with the same time schedule like paraffin

Answer 34

Tissue Mat

Question 35

This wax is harder than paraffin and is not soluble to water

Answer 35

Ester wax

Question 36

It can be used for impregnation without prior clearing of the tissue

Answer 36

Ester wax

Question 37

Heavy duty microtomes used in impregnating with ester wax:

Answer 37

a. Sliding microtome b. Sledge microtome

Question 38

Most commonly used water soluble wax

Answer 38

Carbowax

Question 39

A water soluble wax that does not dehydration and clearing

Answer 39

Carbowa

Question 40

It does not remove neutral fats and lipids

Answer 40

Carbowax

Question 41

Suitable for enzyme histochemical studies

Answer 41

Carbowax

Question 42

Purified form of nitrocellulose

Answer 42

Celloidin impregnation

Question 43

Suitable for hollow cavities, hard and dense tissues such as bones and teeth

Answer 43

Celloidin impregnation

Question 44

Suitable for large sections of embryo

Answer 44

Celloidin impregnation

Question 45

2 Methods of Celloidin impregnation:

Answer 45

1. Wet celloidin 2. Dry celloidin

Question 46

A method of celloidin impregnation that is recommended for bones, teeth, large brain sections and whole organs

Answer 46

Wet celloidin

Question 47

A method of celloidin impregnation that is recommended for whole eyes section

Answer 47

Dry celloidin

Question 48

Dry celloidin uses Gilson's mixture, what does it made up of?

Answer 48

made of equal parts of chloroform and cedarwood oil

Question 49

Another form of celloidin

Answer 49

Nitrocellulose method

Question 50

It has lower viscosity allowing penetration of the tissue rapidly and makes cutting of thinner sections possible

Answer 50

Nitrocellulose methos

Question 51

It is rarely used except when dehydration is to be avoided or the tissues are subjected histochemical and enzyme studies

Answer 51

Gelatin impregnation

Question 52

Prevents fragmentation of tissues when used in frozen section and as embedding medium

Answer 52

Gelatin impregnation