WAX IMPREGNATION

Question 1

Process of replacing the clearing agent with the infiltrating medium to fill all tissue cavities, providing firm consistency for easy handling and thin section cutting

Answer 1

Impregnation (Infiltration)

Question 2

Process where impregnated tissue is positioned in a mold with an embedding medium and allowed to solidify

Answer 2

Embedding (Casting)

Question 3

Most common embedding medium; allows easy cutting of serial sections without distortion; very rapid (prepared within 24 hours); suitable for many staining procedures

Answer 3

Paraffin

Question 4

Melting point for routine work; should not exceed this temperature to avoid tissue damage

Answer 4

56°C

Question 5

Overheating paraffin (>60°C) causes these issues

Answer 5

Brittleness, shrinkage, and hardening

Question 6

Type of tissue for which paraffin embedding is not recommended

Answer 6

Fatty tissues

Question 7

Manual processing requires four changes of paraffin, with this interval between each change

Answer 7

15 minutes

Question 8

Two types of automatic tissue processing

Answer 8

Tissue transfer (dip and dunk) and fluid transfer (enclosed type)

Question 9

Specimens are transferred from container to container for processing

Answer 9

Tissue transfer

Question 10

Specimens are held in a single process chamber or retort where fluids are pumped in and out

Answer 10

Fluid transfer

Question 11

Number of stations in an autotechnicon

Answer 11

12 stations

Question 12

Thermostat setting for wax bath in autotechnicon

Answer 12

3°C higher than the melting point of wax

Question 13

Histopathologic technique steps performed by autotechnicon

Answer 13

Fix,dehydrate, clear, infiltrate

Question 14

First two stations in autotechnicon

Answer 14

10% formalin

Question 15

Stations 3-6 in autotechnicon

Answer 15

Increasing grades of 70-95% ethanol

Question 16

Stations 7-8 in autotechnicon

Answer 16

Acetone

Question 17

Stations 9-10 in autotechnicon

Answer 17

Chloroform or xylene

Question 18

Stations 11-12 in autotechnicon

Answer 18

Liquid paraffin

Question 19

Main advantage of autotechnicon

Answer 19

Constant agitation with vertical oscillation

Question 20

Process of wax impregnation under negative atmospheric pressure inside an embedding oven

Answer 20

Vacuum embedding

Question 21

Vacuum embedding advantages

Answer 21

Hastens removal of air bubbles and clearing agent; promotes rapid penetration of impregnating medium

Question 22

Fastest method for urgent biopsies, delicate tissues, and CNS tissues

Answer 22

Vacuum embedding

Question 23

Mixture of paraffin and synthetic plastic polymer

Answer 23

DMSO

Question 24

Melting point of DMSO

Answer 24

56-57°C

Question 25

Substitute similar to Paraplast

Answer 25

Embeddol

Question 26

Melting point of Embeddol

Answer 26

56-58°C

Question 27

Semisynthetic tissue embedding material for eyes

Answer 27

Biobloid

Question 28

Material used for tissue mat

Answer 28

Rubber

Question 29

Properties of ester wax Melting point: ---

Answer 29

46-48°C, harder than paraffin, water-insoluble but soluble in 95% ethanol

Question 30

Microtome used for ester wax sectioning

Answer 30

Sliding/base sledge microtome

Question 31

Water-soluble waxes

Answer 31

Polyethylene glycols

Question 32

Melting point range of polyethylene glycols

Answer 32

38-42°C or 45-56°C

Question 33

Most common water-soluble wax

Answer 33

Carbowax

Question 34

Properties of Carbowax

Answer 34

Miscible and soluble with water, hygroscopic, no need for clearing and dehydration

Question 35

Uses of Carbowax

Answer 35

Used for enzyme histochemistry

Question 36

Disadvantages of Carbowax

Answer 36

Hygroscopic, dissolves fishing out, crumbles during sectioning

Question 37

Sectioning condition for Carbowax infiltrated tissue

Answer 37

Fish out immediately

Question 38

Composition of Pearse wax

Answer 38

Composed of diethylene glycol, distilled water, and 40% formalin

Question 39

Composition of Blank and McCarthy wax

Answer 39

Equal parts of 0.02% gelatin and 0.02% potassium dichromate

Question 40

Purified form of nitrocellulose

Answer 40

Celloidin

Question 41

Nitrocellulose is preferred for

Answer 41

Nervous tissue (brain), spx with large hollow cavities

Question 42

Celloidin composition

Answer 42

2%, 4%, or 8% dissolved in equal parts of ether and alcohol

Question 43

Celloidin advantages

Answer 43

Less shrinkage, less tissue distortion

Question 44

Processing time for celloidin

Answer 44

Very slow (days to weeks)

Question 45

Celloidin storage for bones, brain sections, teeth

Answer 45

70% alcohol for storage

Question 46

Celloidin storage for whole eye sections

Answer 46

Gilson's mixture (equal parts of chloroform and cedarwood oil)

Question 47

Type of celloidin used for bones, brain, teeth

Answer 47

Wet celloidin

Question 48

Type of celloidin used for whole eye sections

Answer 48

Dry celloidin

Question 49

Preferred method for embedding tissue blocks

Answer 49

Nitrocellulose method (Low Viscosity Nitrocellulose)

Question 50

Solubility of low viscosity nitrocellulose

Answer 50

Soluble in equal concentrations of ether and alcohol

Question 51

Advantages of low viscosity nitrocellulose

Answer 51

Produces harder tissue block, allows thinner sections

Question 52

Additive to prevent tissue cracking in nitrocellulose

Answer 52

Plasticizer (castor oil or oleum ricini)

Question 53

Safety concern for nitrocellulose

Answer 53

Explosive

Question 54

Rarely used; mostly for histochemical and enzyme studies, frozen sections; water soluble

Answer 54

Gelatin

Question 55

Does not require clearing and dehydration

Answer 55

Gelatin

Question 56

Tissue thickness for processing tissues impregnated with gelatin should be less than

Answer 56

2-3 mm

Question 57

Gelatin uses ____ to prevent mold

Answer 57

1% phenol

Question 58

Gelatin impregnating medium volume should be at least ___ the volume of tissue

Answer 58

25x