HISTOPATHOLOGY: INFILTRATION AND EMBEDDING

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

A. Infiltration (Impregnation)

B. Embedding (Casting or Blocking)

A. Infiltration (Impregnation)

Is the process by which the impregnated tissue is placed into a precisely arranged position in a mold containing a medium which is then allowed to solidify

A. Infiltration (Impregnation)

B. Embedding (Casting or Blocking)

B. Embedding (Casting or Blocking)

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

A. Paraffin wax

B. Celloidin (Collodion)

C. Gelatin

A. Paraffin wax

used mainly for preparing soft tissue sections of mixed consistency such as eyes and brain

A. Paraffin wax

B. Celloidin (Collodion)

C. Gelatin

B. Celloidin (Collodion)

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

A. Paraffin wax

B. Celloidin (Collodion)

C. Gelatin

C. Gelatin

Routine Work

A. Paraffin wax with a melting point of 54-58 degrees Celsius is indicated

B. The melting point of wax to be used should be between 50 and 54 degrees Celsius

C. 56 degrees Celsius

C. 56 degrees Celsius

If the laboratory temperature is between 20 to 24 degrees Celsius

A. Paraffin wax with a melting point of 54-58 degrees Celsius is indicated

B. The melting point of wax to be used should be between 50 and 54 degrees Celsius

C. 56 degrees Celsius

A. Paraffin wax with a melting point of 54-58 degrees Celsius is indicated

If the laboratory temperature is between 15 to 18 degrees Celsius

A. Paraffin wax with a melting point of 54-58 degrees Celsius is indicated

B. The melting point of wax to be used should be between 50 and 54 degrees Celsius

C. 56 degrees Celsius

B. The melting point of wax to be used should be between 50 and 54 degrees Celsius

A mixture of highly purified paraffin and synthetic plastic polymers, with a melting point of 56 to 57 degrees Celsius

A. Ester Wax

B. Embeddol

C. Paraplast

C. Paraplast

Is synthetic wax substitute similar to Paraplast with a melting point of 56 to 58 degrees Celsius. It is less brittle and less compressible than Paraplast. Bio/aid is a semisynthetic wax recommended for embedding eyes

A. Ester Wax

B. Embeddol

C. Paraplast

B. Embeddol

Has a lower melting point (46 to 48 degrees Celsius), but it is harder than paraffin. It is not

soluble in water, but is soluble in 95% Ethyl Alcohol and other clearing agents; hence, it can be

used for impregnation without prior clearing of the tissue

A. Ester Wax

B. Embeddol

C. Paraplast

A. Ester Wax

Are plastic polymers, mostly polyethylene glycols with melting points of 38 to 42 degrees

Celsius or 45 to 56 degrees Celsius

A. Water Soluble Waxes

B. Dimethyl Sulphoxide (DMSO)

C. Embeddol

A. Water Soluble Waxes

The most commonly used is Carbowax, a polyethylene glycol containing 18 or more carbon

atoms, which appears solid at room temperature

A. Water Soluble Waxes

B. Dimethyl Sulphoxide (DMSO)

C. Embeddol

A. Water Soluble Waxes

Added to proprietary blends of plastic polymer paraffin waxes reduces infiltration times and facilitates thin sectioning

A. Water Soluble Waxes

B. Dimethyl Sulphoxide (DMSO)

C. Embeddol

B. Dimethyl Sulphoxide (DMSO)

Possible health risks associated with the use of DMSO-paraffin wax are minimal if correct laboratory hygiene is observed

A. Water Soluble Waxes

B. Dimethyl Sulphoxide (DMSO)

C. Embeddol

B. Dimethyl Sulphoxide (DMSO)

Is 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

A. Paraffin wax

B. Celloidin (Collodion)

C. Gelatin

B. Celloidin (Collodion)

Is recommended for bones, teeth, large brain sections and whole organs. After the usual

fixation and dehydration of the tissue, it is placed in equal parts of ether and alcohol for 12-24

hours

A. Wet Celloidin Method

B. Dry Celloidin Method

A. Wet Celloidin Method

Is preferred for processing of whole eye sections. The principle and procedure of this method is similar to wet celloidin method, except that 70% alcohol is not used for storage before cutting

A. Wet Celloidin Method

B. Dry Celloidin Method

B. Dry Celloidin Method

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

A. Compound Embedding Unit

B. Plastic Embedding Rings and Base Mold

C. Disposable Embedding Molds (Peel-Away)

A. Compound Embedding Unit

consist of a special stainless steel base mold fitted with a plastic embedding ring, which later serves as the block holder during cutting

A. Compound Embedding Unit

B. Plastic Embedding Rings and Base Mold

C. Disposable Embedding Molds (Peel-Away)

B. Plastic Embedding Rings and Base Mold

disposable thin plastic embedding molds, available in 3 different sizes, are simply peeled off one at a time, as soon as the wax has solidified, giving perfect even block without trimming. It may be placed directly in the chuck or block holder of the microtome

A. Compound Embedding Unit

B. Plastic Embedding Rings and Base Mold

C. Disposable Embedding Molds (Peel-Away)

C. Disposable Embedding Molds (Peel-Away)

Such as those used in ordinary refrigerators may be recommended for busy routine laboratories. Each compartment may be utilized for embedding one tissue block, which may then be removed by bending the plastic tray once the wax has solidified or by smearing the inner mold with glycerin or liquid paraffin before embedding

A. Disposable Embedding Molds (Plastic Ice)

B. Disposable Embedding Molds (Paper Boats)

C. Celloidin or Nitrocellulose Embedding Method

A. Disposable Embedding Molds (Plastic Ice)

are normally utilized for embedding celloidin blocks but are equally useful for paraffin wax blocks. They have the advantage of being cheap and easy to make. They provide easy and accurate identification of specimen, thereby avoiding confusion and interchange of tissue blocks. Rapid embedding of small or large volume of individual specimen is possible, since paper molds can be made to suit any size of tissue

A. Disposable Embedding Molds (Plastic Ice)

B. Disposable Embedding Molds (Paper Boats)

C. Celloidin or Nitrocellulose Embedding Method

B. Disposable Embedding Molds (Paper Boats)

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. Tissues are embedded in shallow tins of enamel pans which are covered by sheets of weighted glass. Bell jars can be used to control the rate or evaporation of the solvent

A. Disposable Embedding Molds (Plastic Ice)

B. Disposable Embedding Molds (Paper Boats)

C. Celloidin or Nitrocellulose Embedding Method

C. Celloidin or Nitrocellulose Embedding Method

made up of a carefully balanced mixture of epoxy plastic, catalysts and accelerators. Three types of epoxy plastics are used in microscopy, i.e., those based on either bisphenol A (Araldite), or glycerol (Epon) or cyclohexene dioxide (Spurr)

A. Epoxy Embedding Plastics

B. Polyester Plastics

C. Acrylic Plastics

A. Epoxy Embedding Plastics

were originally introduced for electron microscopy in the mid-1950s but have been superseded by more superior epoxides, and are now seldom used

A. Epoxy Embedding Plastics

B. Polyester Plastics

C. Acrylic Plastics

B. Polyester Plastics

made up of esters of acrylic or methacrylic acid, and are used extensively for light microscopy. Polyglycol methacrylate (GMA) has proved to be a popular embedding medium for light microscopy because it is extremely hydrophilic, allowing many staining methods to be applied, yet tough enough when dehydrated to section well on most microtomes

A. Epoxy Embedding Plastics

B. Polyester Plastics

C. Acrylic Plastics

C. Acrylic Plastics