What is the purpose of embedding tissue in paraffin?

The tissue sample is then either embedded in paraffin or frozen. Embedding is important in preserving tissue morphology and giving the tissue support during sectioning. Some epitopes may not survive harsh fixation or embedding.

What is embedding in tissue processing?

Embedding is the process in which the tissues or the specimens are enclosed in a mass of the embedding medium using a mould. Since the tissue blocks are very thin in thickness they need a supporting medium in which the tissue blocks are embedded. This supporting medium is called embedding medium.

What does paraffin embedded mean?

Paraffin Embedding. The infiltrating of tissue specimens with paraffin, as a supporting substance, to prepare for sectioning with a microtome.

Why is sectioning tissue important?

Using serial sections allows the 3D structure of the tissue to be visualized. This is especially important in determining whether an abnormality is an artifact of preparation or a pathologic process. Some tissues are stained and then mounted. More often the tissue is placed on the slide first and then stained.

How is tissue fixation done?

Fixation of tissues can be achieved by chemical or physical means. Physical methods include heating, micro-waving and cryo-preservation (freeze drying). Cryo-preservation, usually in the form of freeze drying has some applications in histochemistry but is not usually applied to diagnostic tissue specimens.

What are the steps in tissue processing?

Overview of the steps in tissue processing for paraffin sections

  1. Obtaining a fresh specimen. Fresh tissue specimens will come from various sources.
  2. Fixation. The specimen is placed in a liquid fixing agent (fixative) such as formaldehyde solution (formalin).
  3. Dehydration.
  4. Clearing.
  5. Wax infiltration.
  6. Embedding or blocking out.

What are the types of embedding?

Embedding Media, Paraffin, Paramat, Paraplast, Peel Away Paraffin, Tissue Freezing Medium, Cryogenic-Gel, O.C.T. Compound, Polyfin, Polyester Wax.

How do you store paraffin-embedded tissue blocks?

You can store paraffin blocks at room temperature in a box for years. But before you start sectioning again put them into the fridge for a couple of hours. This makes sectioning easier. Paraffin section which are not mounted on glas slides could also stored in flat boxes at room teperature over years.

What are the three types of tissue sectioning?

Techniques. For light microscopy, three techniques can be used: the paraffin technique, frozen sections, and semithin sections. The paraffin technique is the most commonly used. Once the sections are prepared, they are usually stained, to help distinguish the components of the tissue.

How long is sectioning of paraffin-embedded tissue protocol?

This protocol describes how to cut sections from tissue embedded in paraffin blocks (2:48 minutes). For other video protocols please visit our video protocol library here. Materials and Reagents

How to section a tissue block with paraffin?

Sectioning 1 Chill paraffin-embedded tissue blocks on ice before sectioning. 2 Fill a waterbath with ultrapure water and heat to 40-45 o C. 3 Place the blade in the holder, ensure it is secure and set the clearance angle. 4 Insert the paraffin block and orientate so the blade will cut straight across the block.

What’s the protocol for immunohistochemistry for paraffin embedded sections?

Immunohistochemistry Protocol for Paraffin-Embedded Sections Protocol Steps Prepare formalin-fixed, paraffin-embedded tissue sections (steps 1-8): Fix freshly dissected tissue (less than 3 mm thick) with 10% formalin or other fixatives for 24-48 hour at room temperature. Caution:Formalin is a suspected carcinogen.

How is cold wax used to section paraffin?

Cold wax allows thinner sections to be obtained by providing support for harder elements within the tissue specimen. The small amount of moisture that penetrates the block from the melting ice will also make the tissue easier to cut. Fill a waterbath with ultrapure water and heat to 40-45 o C.