[Histonet] Deparaffinization for EM

[mtitford <@t> aol.com]

Mark Elliot  asks about processing FFPE tissue for EM. Hayat published a method in his book we use. Briefly you dig out 1mm cube pieces of tissue from the block and rotate them in xylene for one hour, followed by absolute, 95%, 70%,50% alcohols for 15 minutes each and then into your EM buffer overnight, followed by your normal EM processing next day. The EM image looks pretty grotty but if your pathologist can make a diagnosis it is worth it.
(Hayat M.A. Principles and techniques of electron microscopy. 2ed edition. Baltimore. University Park Press. 1981 page 209)
In another method published years ago, someone by-passed the hydration steps by deparaffizing in osmium dissolved in xylene, then going straight to Epon.

Hope this helps

Michael Titford
Pathology USA
Mobile AL USA