HISTOPATH: IMPREGNATION

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

• Impregnation
• Infiltration

Impregnation gives a firm consistency to the specimen

• True
• False

Impregnation allows easier handling and cutting of suitably thin sections without any damage or distortion to the tissue and its cellular components

• True
• False

Embedding medium: the medium used to infiltrate the tissue is usually the same medium utilize for impregnation

• Paraffin wax
• Celloidin (Collodion)
• Gelatin
• Plastic

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

• Paraffin Wax Impregnation
• Celloidin (Collodion) Impregnation
• Gelatin Impregnation

A purified form of nitrocellulose soluble in many solvents ▪ suitable for specimens with large hollow cavities ▪ suitable for hard and dense tissues ▪ suitable for large tissue sections of the whole embryo ▪ recommended for processing of neurological tissues

• Paraffin Wax Impregnation
• Celloidin (Collodion) Impregnation
• Gelatin Impregnation

Is rarely used except when dehydration is to be avoided ▪ used when tissues are subjected to histochemical and enzyme studies ▪ used as an embedding medium for delicate specimens and frozen tissue sections ▪ tissues should not be more than 2-3 mm thick ▪ 1% phenol prevents the growth of molds ▪ The volume of the impregnating medium should be at least 25 times the volume of the tissue

• Paraffin Wax Impregnation
• Celloidin (Collodion) Impregnation
• Gelatin Impregnation

Paraffin Wax Impregnation Advantages

• thin individual serial sections may be cut with ease without undue distortion
• process is very rapid
• tissue blocks and unstained mounted sections may be stored for an indefinite period of time after impregnation without considerable tissue destruction
• many staining procedures are permitted with good results

Paraffin Wax Impregnation: Paraffin oven or incubator

• 55-60℃
• 45℃, 52℃, 56℃, 58℃
• 56℃
• 54-58℃

Paraffin Wax Impregnation: Melting points of common waxes:

• 55-60℃
• 45℃, 52℃, 56℃, 58℃
• 56℃
• 54-58℃