Cutting - tips

                   Soaking blocks with water 

When tissue is exposed on the surface of a paraffin block by rough trimming it has the capacity to absorb water. It will penetrate a small distance into the tissue softening and swelling it. With poorly processed tissue (both under- and over-processed) this effect may helps to cut sections.

With difficult blocks the procedure entails very careful trimming (rough cut) to expose the tissue while avoiding too much damage to the specimen surface, then placing it face up on the top of the ice tray. Add few drops of water just to cover the tissue on the block (PICTURE A).  Keep it  for at least 2-3 minutes.  The block should be re-chilled in the ice tray before attempting to obtain sections.  It is vital that alignment of the block face in the microtome is preserved so that no tissue is wasted in obtaining a full-face section. Generally, after this procedure, the best quality sections are achieved by cutting very slowly. 

This technique helps to cut any difficult blocks such as skin, bone, nail etc. Especially tissues containing blood (e.g. endometrial samples) can be easily cut by using this method and can avoid creased and flapped sections.  

For heavily keratinised skin or nail specimens treat block face with NairTM or VeetTM (hair removal products). But  soaking the block in water is the easiest way to cut sections without any damage in the tissue architecture. 

 PICTURE A (Skin punch Biopsy)

                                                                                        

Cutting Levels

This is a simple and easy way to cut levels. When you cut levels, leave sections in the water bath and after finish cutting all levels you can  pick sections on the slide. This allows saving time and it helps to get rid of the creases. Make sure that the sections are attached to the side of the water bath to avoid confusion (PICTURE B). 

PICTURE B (3levels of a skin punch)