Re: fixation of CJD brain

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From:LuAnn Anderson <>
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Responding to the message of 
from "Smith, Allen" <>:

Formic acid, while not 100% efective in deactivating prions, has been found to 
be more effective than Phenol which has been used in the past.  Phenol has been 
shown to not be as effective as once was thought-phenol treated tissues were 
still able to produce disease upon injection.  While nothing is 100%, both the 
CDC and NIH now recommend formic acid treatment followed by further formalin 
fixation overnight as the deactivation procedure.  If you need further details, 
I would be happy to provide them.
LuAnn Anderson,HT(ASCP)
Assistant Scientist-Neuropathology Histotech
> CJD is caused by a prion.  While prions are not affected by formaldehyde,
> they are inactivated by phenol.  Several antique fixatives include phenol.
> They should produce safe paraffin sections of CJD material.  Hetherington's
> fluid is 100 ml absolute ethanol, 75 ml chloroform, 50 ml phenol, and 25 ml
> glacial acetic acid; it dehydrates as well as fixes.  Lendrum's fluid is 75
> ml absolute ethanol,  10 ml chloroform,  10 ml water,  4 ml phenol, and 3 ml
> glacial acetic acid.  I suspect that Behrens' fluid contains too little
> phenol (1%) to be an effective disinfectant.
> .

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