Impregnation

Question 1

Enumerate advantages of impregnation (3)

Answer 1

✨ Easier handling
✨ Firm consistency of the specimen
✨ Cutting of suitably thin section w/o damage/distortion tothe tissue and cellular components

Question 2

Types of tissue impregnation and embedding media (4)

Answer 2

✨Paraffin wax
✨Celloidin (collodion)
✨Gelatin
✨Plastic

Question 3

The simplest, most common and best embedding medium used for routine tissue processing

Answer 3

Paraffin

Question 4

✨how many times will you submerged a tissue in a melted paraffin wax after it has been completely cleared?

Follow-up Qs:
✨ what instrument/s will you use?
✨ regulated temp of the instrument?

Answer 4

✨ two or more changes
✨ paraffin oven; incubator
✨ 55-60 degrees C

Question 5

Melting point of waxes (4)

Answer 5

✨ 45 C
✨ 52 C
✨ 56 C
✨ 58 C

Question 6

temperature of wax normally used for routine work?

Answer 6

✨ 56 C

Question 7

The process whereby the clearing agent is completely removed from the tissue and replaced by a medium that will completely fill all the tissue cavities

Answer 7

Impregnation (infiltration)

Question 8

lab temp ranging from 20-24 C, what is the temp range of the paraffin wax?

Answer 8

54-58 C

Question 9

lab temp ranging from 15-18 C, what is the temp range of the paraffin wax?

Answer 9

50-54 C

Question 10

3 methods of paraffin wax impregnation and embedding

Answer 10

✨ Manual processing
✨ Automatic processing
✨ Vacuum embedding

Question 11

For manual processing, how many mins is required in order to ensure complete removal of the clearing agent from the tissue?

Answer 11

15 mins (at least 4 changes)

Question 12

For manual processing how many hours is needed to ensure complete embedding or casting of tissue?

Answer 12

3 hrs

Question 13

this method makes use of an automatic tissue processing machine w/c fixes, dehydrates, clears and infiltrates tissues?

example of this machine?

Answer 13

✨ automatic processing

✨ Autotechnicon; Elliot bench-type processor

Question 14

how many processing steps in automatic processing?

Answer 14

✨ 12 individual processing steps

Question 15

in automatic processing, how many glass beakers are present? and what is their capacity?

Answer 15

✨ ten 1-liter glass beakers

Question 16

moves the tissues from one processing reagent to another

Answer 16

transfer arm

Question 17

what is the temperature of wax bath thermostats?

Answer 17

✨ Atleast 3°C above the melting point of the wax

Question 18

process which involves the wax impregnation under negative atmospheric pressure inside an embedding oven to hasten removal of air bubbles and clearing agent to promote more rapid wax penetration of the tissue

Answer 18

Vacuum embedding

Question 19

vacuum pressure

Answer 19

✨ not more than 500 mmHg (400-450 mmHg)

Question 20

in vacuum embedding, what example of organ undergoes wax impregnation and removal of any residual air bubbles?

Answer 20

Lungs

Question 21

Vacuum embedding is recommmended for (2)?

Answer 21

1) Urgent biopsies
2) Delicate tissues such as:
✨lung
✨brain
✨ CT
✨ decalcified bones
✨ eyes
✨spleen
✨ CNS

Question 22

Factors that affects the total impregnation time (3)

Answer 22

✨Nature of the tissue
✨ size of the tissue
✨ type of clearing agent used

Question 23

benzene and xylene are _____ removed from the tissues

Answer 23

easily

Question 24

chloroform and cedarwood oil are _____ to remove from tissues

Answer 24

difficult

Question 25

addition of this clearing agent may hasten displacement of cedarwood oil will less tissue shrinkage

Answer 25

benzene

Question 26

Prolonged treatment in melted paraffin causes ______ and ______ tissues

Answer 26

shrinkage; hardening

Question 27

Infiltration in ________ (temp?) will also produce shrinkage and hardening of tissues and destroy ________ (what kind of tissue?) completely.

Answer 27

✨overheated paraffin ( above 60°C ) | ✨lymphoid tissues

Question 28

what is the temperature range of paraffin to be used for impregnation?

Answer 28

2 to 5°C about the melting point of the paraffin

Question 29

paraffin wax must be _____

Answer 29

pure

Question 30

how many times can you use a paraffin wax?

Answer 30

twice

Question 31

temp needed in heating a wax to remove water?

Answer 31

100-105°C

Question 32

substitutes for paraffin wax

Answer 32

✨paraplast ✨ester wax ✨water soluble waxes

Question 33

mixture of highly purified paraffin and synthetic plastic polymers

Answer 33

paraplast

Question 34

melting point of paraplast

Answer 34

56-57°C

Question 35

substitute to paraplast

Answer 35

embeddol

Question 36

melting pount of embeddol

Answer 36

56-58°C

Question 37

a semisynthetic wax recommended for embedding eyes

Answer 37

bioloid

Question 38

Product of paraffin containing rubber

Answer 38

Tissue mat

Question 39

melting point of ester wax

Answer 39

46-48 °C

Question 40

Harder than paraffin

Answer 40

ester wax

Question 41

ester wax is soluble in ?

Answer 41

95% ethanol and other clearing agents (cellosolve and xylene)

Question 42

can be used for impregnation without clearing of the tissue

Answer 42

ester wax

Question 43

when using ester wax, how many changes of wax is required to ensure complete tissue impregnation?

Answer 43

3-4 changes

Question 44

how many hrs is needed in immersing the tissue in a solution containing equal proportion of clearing agent and ester wax before tranferring to pure wax?

Answer 44

3-6 hrs

Question 45

These are mostly polyethylene glycols

Answer 45

Water soluble waxes

Question 46

melting point of water soluble waxes

Answer 46

38-42°C or 45-56°C

Question 47

A polyethylene glycol containing 18 or more carbon atoms, appears solid at room temp

Answer 47

Carbowax

Question 48

the reason why carbowax does not require dehydration and clearing of the tissue?

Answer 48

It is soluble in and miscible with water

Question 49

Reduces tissue distortion and promote flattening and "floating out" of sections

Answer 49

soap; 10% polyethylene glycol 900

Question 50

A purified form of nitrocellulose soluble in many solvents

Answer 50

Celloidin

Question 51

Uses of celloidion

Answer 51

- for specimens w/ large hollow cavities w/c tend to collapse - for hard & dense tissues (bones,teeth) - large tissue sections of the whole embryo

Question 52

Two methods for celloidin impregnation

Answer 52

1) Wet celloidin method | 2) Dry celloidin method

Question 53

example of heavy duty microtome in sectioning ester wax

Answer 53

sliding or sledge type microtome

Question 54

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

Answer 54

Wet CM

Question 55

type of celloidin method preferred for processing of whole eye sections

Answer 55

Dry CM

Question 56

tissue block in Wet cm is stored in ____ to avoid dehydration and tissue shrinkage ?

Answer 56

70-80% alcohol

Question 57

tissue block in Dry cm is stored in _____?

Answer 57

Gilson's mixture (chloroform & cedar wood oil)

Question 58

Another form of celloidin soluble in equal concentration of ether and alcohol w/ a lower viscosity

Answer 58

Low Viscosity Nitrocellulose (LVN)

Question 59

Forms a harder tissue block and makes cutting of thinner sections possible

Answer 59

LVN

Question 60

Example of plasticizers that prevents the tendency of tissues to crack when embedding chrome-mordanted tissues using LVN

Answer 60

- oleum ricini | - castor oil

Question 61

type of impregnation used when dehydration is to be avoided and when tissues are to be subjected to histochemical and enzyme studies

Answer 61

Gelatin impregnation

Question 62

Thickness of tissue used in gelatin impregnation

Question 63

Act as a tissue softener and prevents the growth of molds

Answer 63

1% phenol