Responding to the message of 
<3.0.6.16.20000306160008.43f73708@trex2.oscs.montana.edu>
from Gayle Callis <uvsgc@msu.oscs.montana.edu>:

We are all at risk for those "unknown" cases which pop in unexpectedly and thats
the reason for Universal Precautions.  CJD patients exhibit some very distinct 
symptoms which would prompt a clinician to suspect CJD and awareness is much 
more acute these days. MRI's show distinctive changes in the brain which would 
also be consistant with CJD.  In our facility the combination of symptoms and 
other tests (MRI,CAT scans) would make a specimen suspect and it would then be 
treated as possible CJD. As stated, we can't help the occassional case which may
pop through (it's yet to happen to me, knock on wood), but with the awareness of
the prion protein diseases and attention to the clinical picture, it is less 
likely to go undetected now than before.  Most hospitals and neurosurgeons will 
NOT perform biopsies on possible CJD cases because of the decontamination 
problems in the OR suite and with surgical instruments. This has been a known 
source of transmission.  Contrary to Gayle's comment, there is NO sure or safe 
way to decontaminate a cryostat  (or microtome for that matter) when working 
with Prions.  NOTHING is 100% effective in deactivating the prion protein. 


> 
> I stand corrected, on proven cases of CJD, then CDC and other guidelines
> are clear, obviously.  I was more concerned with the UNKNOWN cases, can one
> be 100% sure what you are cutting is NOT infected with agents that concern
> us all, even in the research setting.  That is more of a dilemma.  So what
> do you do then, if it is an unknown, cut or not cut as a blanket policy?
> That is what I was reading into the comments, but probably missed the key
> point in the first place, the words KNOWN CASES.         
> 
> Even in our research facility, blanket policies do exist:  no HIV infected
> tissues from research projects, fresh frozen;  no human tissues known or
> unknown origins, fixed or unfixed fresh frozen.  Yup, it works for all of
> us. BUT we still have to deal with the unknowns, same as clinical settings.
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> Gayle Callis
> Veterinary Molecular Biology
> Montana State University
> Bozeman MT 59717-3610
> 406 994-4705
> 406 994-4303
> 
> 
> .