[M] Week 9 Decalcification, Dehydration, Clearing, Impregnation, and Embedding - Part 2

Question 1

• or infiltration is 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 and give a firm consistency to the specimen.
• This allows easier handling and cutting of suitably thin sections without any damage or distortion to the tissue and its cellular components.

Answer 1

Impregnation

Question 2

IMPREGNATING MEDIUMS

The medium used to infiltrate the tissue is usually the same medium utilized for impregnation, and for general purposes is known as an

Answer 2

Embedding Medium

Question 3

IMPREGNATING MEDIUMS

There are generally four types of impregnations and embedding medium, namely:

Answer 3

1. Paraffin Wax (most common)
2. Celloidin
3. Gelatin
4. Plastic: not commonly used

Question 4

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

Answer 4

Paraffin

Question 5

There are three ways by which paraffin wax impregnation and embedding of tissues may be performed, what are those?

Answer 5

1. Manual Processing
2. Automatic Processing
3. Vacuum Processing

Question 6

PARAFFIN WAX IMPREGNATION

At least four changes of wax are required at 15 minutes intervals in order to ensure complete removal of the clearing agent from the tissue.

Answer 6

Manual Processing

Question 7

PARAFFIN WAX IMPREGNATION

• This method makes use of an automatic tissue processing machine (i.e.,Autotechnicon) which fixes, dehydrates, clears and infiltrates tissues, thereby decreasing the time and labor needed during the processing of tissues.
• This results in a more rapid diagnosis with less technicality. Usually, only 2- 3 changes of wax are required to remove the clearing agent and properly impregnate the specimen.
• This is made possible due to constant tissue agitation which accelerates and improves tissue penetration giving rise to more consistent results

Answer 7

Automatic Processing

Question 8

pa study nalang ng tissue processing schedule

Answer 8

kay

Question 9

PARAFFIN WAX IMPREGNATION

Vacuum embedding involves wax impregnation under negative atmospheric pressure inside an embedding oven.

Answer 9

Vacuum Processing

Question 10

SUBSTITUTE FOR PARAFFIN WAX

Answer 10

• Paraplast
• Ester wax
• Water soluble waxes

Question 11

SUBSTITUTE FOR PARAFFIN WAX

• It is a mixture of highly purified paraffin and **synthetic
  plastic polymers **
• Melting point: 56-57°C
• Comes in two forms— Embeddol and Tissue mat

Answer 11

Paraplast

Question 12

Paraplast

• Is a synthetic wax substitute
  similar to Paraplast
• Melting point: 56-58°C

Answer 12

Embeddol

Question 13

Paraplast

Is a product of paraffin, containing rubber, with the\ same property as Paraplast.

Answer 13

Tissue mat

Question 14

SUBSTITUTE FOR PARAFFIN WAX

Has a lower melting point (46-48°C), but it is harder than paraffin

Answer 14

Ester wax

Question 15

SUBSTITUTE FOR PARAFFIN WAX

• Are plastic polymers, mostly polyethylene glycols.
• Melting points of:
  ○ 38-42°C
  ○ 45-56°C
• The most commonly used is Carbowax, a polyethylene glycol containing 18 or more carbon atoms, which appears solid at room temperature.

Answer 15

Water Soluble Waxes

Question 16

IMPREGNATING MEDIUMS

• a purified form of nitrocellulose soluble in many solvents
• Suitable for specimens with large hollow cavities which tend to collapse, for hard and dense tissues such as bones and teeth and for large tissue sections of the whole embryo.

Answer 16

CELLOIDIN IMPREGNATION

Question 17

Celloidin Impregnation are supplied in what percentage?

Answer 17

in thin (2%), medium (4%) or thick (8%) solutions of cellulose dissolved in equal parts of ether and alcohol.

Question 18

Two methods are used for celloidin impregnation of tissue

Recommended for bones,
teeth, large brain sections
and whole organs

Answer 18

Wet Celloidin Method

Question 19

Two methods are used for celloidin impregnation of tissue

Preferred for processing
of whole eye sections

Answer 19

Dry Celloidin Method

Question 20

CELLOIDIN IMPREGNATION

Low Viscosity Nitrocellulose (L.V.N.) is another form of celloidin soluble in equal concentration of ether and alcohol, with a lower viscosity, allowing it to be used in higher concentrations and still penetrate tissues rapidly.

Answer 20

Nitrocellulose

Question 21

impregnation

• Is rarely used except when dehydration is to be skipped or avoided and when tissues are to be subjected tohistochemical and enzyme studies.
• It is used as an embedding medium for delicate specimens and frozen tissue sections because it prevents fragmentation of tough and friable tissues when frozen sections are cut.

Answer 21

Gelatin Impregnation

Question 22

• Also known as casting or blocking
• After impregnation, the tissue is placed into a mold containing the embedding medium and this medium is allowed to solidify. Basically, the impregnated tissue will be placed in a block of paraffin.
• Ideally, the embedding medium should match the tissue type in strength and hardness.

Answer 22

Embedding

Question 23

Embedding

TOF

• If the embedding medium is too HARD for the material, the tissue will not be supported and sections will be torn or shredded.
  If the medium is too SOFT for the tissue, sections will be brittle and will shatter.

Answer 23

• False (soft)
• False (Hard)

Question 24

Embedding

1. To infiltrate the tissues with supporting embedding medium,
   tissues must be ____ (since usually embedding medium is not miscible with water).
2. Paraffin embedded tissues are arranged at the bottom of the mold together with their proper labels and immersed in melted paraffin at a temperature between____ above its melting point and then cooled rapidly in a refrigerator at ____ or immersed in ____ to solidify. This will allow hardening of tissues, giving them a firmer consistency and better support, thereby facilitating the cutting of sections.

Answer 24

1. Free of all water
2. 5-10°C
   - -5°C or
   immersed in cold water

Question 25

TYPES OF BLOCKING-OUT MOLDS

Answer 25

1. Leuckhart’s Embedding Mold 2. Compound Embedding Unit 3. Plastic Embedding Rings and Base Mold 4. Disposable Embedding Molds

Question 26

# TYPES OF BLOCKING-OUT MOLDS This consists of **two L-shaped strips** of heavy brass or metal arranged on a flat metal plate and which can be moved to adjust the size of the mold to the size of the specimen

Answer 26

Leuckhart’s Embedding Mold

Question 27

# TYPES OF BLOCKING-OUT MOLDS * It is made up of a **series of interlocking plates** resting on a flat metal base, forming several compartments. * It has the **advantage of embedding more specimens at a time**, thereby reducing the time needed for blocking.

Answer 27

Compound Embedding Unit

Question 28

# TYPES OF BLOCKING-OUT MOLDS * It consists of a **special stainless steel base mold fitted with a plastic embedding ring,** which later serves as the block holder during cutting.

Answer 28

Plastic Embedding Rings and Base Mold

Question 29

# TYPES OF BLOCKING-OUT MOLDS Includes **peel-away, plastic ice trays, and paper boats.**

Answer 29

Disposable Embedding Molds

Question 30

- The process by which a tissue is arranged in precise positions in the mold during embedding, on the microtome before cutting, and on the slide before staining * The surface of the section to be cut should be placed parallel to the bottom of the mold in which it is oriented.

Answer 30

ORIENTATION

Question 31

OTHER EMBEDDING METHODS

Answer 31

1. Celloidin or Nitrocellulose Embedding Method 2. Double-Embedding Method 3. PLASTIC (RESIN) EMBEDDING METHOD

Question 32

# OTHER EMBEDDING METHODS Used to be recommended for embedding **hard tissues** such as bones and teeth, and for large sections of whole organs like the **eye**, since the delicate layers of the eyeball are difficult to keep intact when other media are used

Answer 32

Celloidin or Nitrocellulose Embedding Method

Question 33

# OTHER EMBEDDING METHODS The process by which tissues are first embedded or fully infiltrated with a supporting medium such as **agar or nitrocellulose**, then infiltrated a second time with paraffin wax in which they are subsequently embedded.

Answer 33

Double-Embedding Method

Question 34

# OTHER EMBEDDING METHODS Classified into epoxy, polyester, or acrylic, based on their chemical composition

Answer 34

PLASTIC (RESIN) EMBEDDING METHOD