What is paraffin sectioning?
Paraffin sectioning is the procedure of cutting thin slices of tissue that has been dehydrated and infiltrated with wax using specialized equipment. This tissue is then embedded in wax before being cut on a microtome.
What is paraffin embedding technique?
Paraffin embedding is a standard technique used in clinical and research laboratories to create a formalin-fixed, paraffin-embedded (FFPE) block of tissue. Formalin-fixed tissue undergoes tissue processing and then is embedded in paraffin (wax) to create a FFPE block or paraffin block.
Why paraffin wax is used in microtome sectioning?
Alternatively, we can infiltrate our tissue specimen with a liquid agent that can subsequently be converted into a solid that has appropriate physical properties, which will allow thin sections to be cut from it. Paraffin wax is such an agent. This produces so-called “paraffin sections”.
How are paraffin sections dried?
Slides should be placed in a slide dryer or oven for 15-20 minutes to dry out water before deparaffinization. Slides can also be dried over night at room temperature to allow tissue to adhere better to the slides. The temperature of drying ovens should be at, or just above, the melting point of paraffin.
How paraffin sections are dried?
Place paraffin ribbon in water bath at about 40-45 ºC. Mount sections onto slides. Allow sections to air dry for 30 minutes and then bake in 45-50 ºC oven overnight. NEVER allow baking temperature go higher than 50 ºC for sections thicker than 25um.
How do you prepare tissue for paraffin embed?
Dehydrate the tissue through 70%, 80%, and 95% alcohol, 45 min each, followed by 3 changes of 100% alcohol, 1 hour each. Clear the tissue through 2 changes of xylene, 1 hour each. Immerse the tissue in 3 changes of paraffin, 1 hour each. Embed the tissue in a paraffin block.
How are paraffin sections prepared in the lab step by step?
Sectioning Protocol:
- Section paraffin blocks at the desired thickness (usually 4-5 µm) on a microtome and float on a 40°C water bath containing distilled water.
- Transfer the sections onto a Superfrost Plus slide. Allow the slides to dry overnight and store slides at room temperature until ready for use.
Why is paraffin used for embedding?
The most widely used embedding medium for biological applications is paraffin wax, or ‘paraffin. ‘ Paraffin wax is insoluble in water but dissolves in toluene and xylene and melts at 46–68 °C, making it an ideal medium for embedding tissues after they have been dehydrated.
Why do we embed 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.
Why paraffin wax is used?
Paraffin wax is a white or colorless soft, solid wax. It’s made from saturated hydrocarbons. It’s often used in skin-softening salon and spa treatments on the hands, cuticles, and feet because it’s colorless, tasteless, and odorless. It can also be used to provide pain relief to sore joints and muscles.
What is the purpose of paraffin wax in histopathology?
In histopathology, paraffin wax is used for embedding surgical specimens. Hot liquid wax is dispensed into a small tray and allowed to cool. A specimen is placed into the cooling wax in the desired orientation.
How do you cut paraffin wax blocks?
Insert the paraffin block and orientate so the blade will cut straight across the block. Carefully, approach the block with the blade and cut a few thin sections to ensure the positioning is correct. Adjust if necessary. Trim the block to expose the tissue surface to a level where a representative section can be cut.
What are the most important steps during the paraffin technique?
Overview of the steps in tissue processing for paraffin sections
- Obtaining a fresh specimen. Fresh tissue specimens will come from various sources.
- Fixation. The specimen is placed in a liquid fixing agent (fixative) such as formaldehyde solution (formalin).
- Dehydration.
- Clearing.
- Wax infiltration.
- Embedding or blocking out.
What is the use of paraffin wax in laboratory?
In a histology or pathology laboratory, paraffin wax is used to impregnate tissue prior to sectioning thin samples of tissue. Water is removed from the tissue through ascending strengths of alcohol (75% to absolute) and the tissue is cleared in an organic solvent such as xylene.
How do you cut blocks of wax?
Stick the knife into a section of beeswax near the edge and begin wiggling. I’ve found wiggling the knife into the beeswax and breaking it apart that way is quicker than trying to slice/chop, easier on my hands, and safer.
What is paraffin sectioning in dentistry?
Paraffin Sectioning. Paraffin sectioning is the procedure of cutting thin slices of tissue that has been dehydrated and infiltrated with wax using specialized equipment. This tissue is then embedded in wax before being cut on a microtome.
How do you make a paraffin section?
Paraffin Section Method and Technique. Trim paraffin blocks as necessary and cut at 3-10 um (5 um is commonly used). Place paraffin ribbon in water bath at about 40-45 º C. Mount sections onto slides. Allow sections to air dry for 30 minutes and then bake in 45-50 º C oven overnight. NEVER allow baking temperature go higher than 50 ºC…
What is the difference between paraffin and frozen sectioning?
Frozen sectioning is the procedure of cutting thin sections of frozen tissue and is conducted in a cryostat. While frozen sections are physically less stable than paraffin, they are especially superior in the preservation of antigenicity and lipid retention.
Why are tissue samples embedded in paraffin Before sectioning?
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.