Infiltration and Embedding

1. TRUE

2. TRUE

MODIFIED TRUE OR FALSE

1. Infiltration is compatible with any staining procedures

2. Infiltration allows cutting of serial sections with ease

1. FALSE

2. FALSE

MODIFIED TRUE OR FALSE

1. Celloidin Infiltration requires heat

2. Double-embedding process only uses one support media

1. FALSE

2. TRUE

MODIFIED TRUE OR FALSE

1. Compound Embedding Mold consists of 2 L-shaped strips of heavy brass or metal

2. Tissue mat is a product of paraffin with rubber

1. TRUE

2. FALSE

1. Paraplast is a mixture of highly purified paraffin and synthetic plastic polymers

2. Infiltration is suited for fatty tissues

65 or 70 degC

Paraffin is solid at room temperature but melts at temperatures up to about?

Brittle

Overheated paraffin makes the specimen _________.

Retention

Inadequate impregnation will promote __________ of the clearing agent.

Cell shrinkage and tissue hardening

Prolonged infiltration may cause?

Retention of clearing agent

Inadequate infiltration may cause?

Fatty tissues

Infiltration is not suited for which type of specimen?

56 degC

Melting point of paraffix wax used in routine processing is?

2-3 changes

In automatic processing, how many changes of wax are required to remove the clearing agent and properly impregnate the specimen?

An oven

Manual method of infiltration is carried out using?

4 changes

Manual method of infiltration requires how many changes of wax at 15 minutes interval?

1 hour

Manual method of infiltration may be completed in?

Autotechnicon

Automatic method of infiltration employs the use of?

Vacuum Impregnation

• The most rapid method of infiltration

• It involves wax impregnation under negative atmospheric pressure inside an embedding oven

  Recommended for urgent biopsies and for spx such as:

  • Lungs

  • Brain

  • Eyes

  • Spleen

  • CNS

Stopcock

It prevents water from being sucked back into the trap bottle and vacuum chamber when the water or suction pump is closed

Paraplast

It is a mixture of highly purified paraffin and synthetic plastic polymers

4 hours

Tissues should not be left in the paraffin oven for more than how many hours?

Twice

Paraffin wax can only be used how many times after it is replaced with fresh wax?

56-57 degC

The melting point of Paraplast is?

• Bone

• Brain

Paraplast is used for what type of spx/s?

Embeddol

It is similar to Paraplast, but with a higher melting point.

56-58 degC

The melting point of Embeddol:

Bioloid

It is a semisynthetic wax recommended for infiltrating eye specimens

Ester wax

• It is harder than paraffin wax but has a lower melting point, and requires heavy duty type of microtome

• It is soluble in 95% Ethyl Alcohol; it does not require clearing

46-48 degC

Melting point of Ester wax:

Tissue mat

It is a product of paraffin, containing rubber, with the same property as Paraplast

Carbowax

• A polyethylene glycol containing 18 or more carbon atoms, which appears solid at room temperature.

• It is a water soluble wax for enzyme histochemistry

  ADVANTAGE:

  • Eliminates dehydration and clearing process

  DISADVANTAGE:

  • Tissues are difficult to float out when cut

Dimethyl sulfoxide (DMSO)

• It is added to proprietary blends of plastic polymer paraffin waxes to reduce infiltration times and facilitates thin sectioning

• It has an unpleasant and annoying oyster or garlic taste when used

Celloidin Infiltration

• a.k.a Colloidon

• It is a purified form of nitrocellulose that is soluble in alcohol and ether

• Does not require heat during processing

  DISADVANTAGE:

  • Process is very slow due to no heat application

Large and hollow cavities that tends to collapse:

• Bones

• Brain

• Teeth

• Whole organs

Celloidin Infiltration is used for tissues with:

Wet Celloidin

• Uses 70% alcohol for storage

• For infiltrating bones, brain, teeth, and whole organs

Dry Celloidin

• Uses Gilson’s Mixture for storage

• For infiltrating whole eye specimens

Gilson’s Mixture

Dry Celloidin uses _______ for storage

70% alcohol

Wet Celloidin uses _________ for storage

• Chloroform

• Cedarwood oil

Gilson’s Mixture is made up of equal parts of?

Low Viscosity Nitrocellulose

• Another form of celloidin soluble in equal concentrations of ether and alcohol

• It is more explosive than celloidin and should therefore be handled with care

• It produces harder tissue blocks and allows cutting of thinner sections

• It needs Plasticizers to prevent cracking

• Oleum ricini

• Castor oil

Types of plasticizers:

Gelatin Impregnation

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

• 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

• It is water-soluble, and does not require dehydration and clearing.

Should not be more than 2-3mm thick

Tissue for processing in Gelatin Infiltration:

Put in a container of 10% gelatin with 1% phenol for 24 hours

Procedure for Gelatin Infiltration:

Torn / shredded

If embedding medium is too soft, the tissue will be:

Brittle and will shatter

If embedding medium is too hard for the tissue, sections will be:

1% Phenol

Preservative used in Gelatin Infiltration:

Trimming

It is a process which involves cutting excess wax to produce a four-sided prism

Leuckhart’s Mold

It consists of two L-shaped strips of heavy brass or metal arranged on a flat metal plate.

Compound Embedding Mold

It is made up of a series of interlocking plates resting on a flat metal base, forming several compartments

Tissue Tek

It is equipped with a warm plate to manage the impregnated specimen, and a cold plate at -5°C for rapid solidification of the block

• Leuckhart’s Mold

• Compound Embedding Mold

• Plastic Embedding rings

• Base molds

• Tissue Tek

Non-disposable embedding molds:

• Peel away mold

• Plastic ice trays

• Paper boat

Disposable embedding molds:

Peel away mold

• It is the most common embedding mold

• This mold gives a perfect block without trimming

Paper boat

• It is normally utilized for embedding celloidin blocks but are equally useful for paraffin wax blocks

• They provide easy and accurate identification of specimen

• This mold can be made to suit any size of tissue

Four-sided prism

What is the shape of Peel away mold?

Double-Embedding process

• It is the process in which tissues are first infiltrated with celloidin and subsequently embedded in paraffin

• It uses two support media at the same time

Orientation

It is the process by which a tissue is arranged in a precise position

Epon

Glycerol-based epoxy plastics that have a lower viscosity but are often sold as mixtures of isomers

Spurr’s Resin

• Cyclohexene dioxide-based plastic that has a low viscosity mixture which provides rapid infiltration of tissues.

• It is easy to prepare and mixes rapidly

Vinyl cyclohexane dioxide (VCD)

The component of epoxy plastics that is known to be carcinogenic

Polyester plastics

They were originally introduced for EM in the mid 1950s, but have been superseded by more superior epoxides, and are now seldom used.

Acrylic plastics

They are made up of esters of acrylic or methacrylic acid, and are used extensively for LM.

Glycol methacrylate (GMA)

2-hydroxyethyl methacrylate is commonly known as?