Dear Histonetters,

I am glad Ian has brought up the subject of cryostats fitted with vacuum
debris collectors.  This is something which has given me cause for concern
for some time and I have been unable to obtain any information on how safe
these systems are.  I have brought this subject up before on the
Histonette, as has Russ Allison, and neither of us received any useful
information from our fellow histonetters.  Does anyone have any information
on whether these systems are really safe, do they filter out viruses etc?
Peggy does your Federal Registry and CAP have any views on this?  Perhaps
the manufacturers would like to comment and give us all peace of mind as to
what safety criteria they put their instruments through before they sell
them to us.?

I contacted a senior member of our Virology department to-day regarding
their safety or clean air cabinets filtration systems.  I thought if anyone
knows about safe filtration systems it will be the virologists.  By
preference, despite their super duper filtration systems, all their
cabinets are connected to an exterior extraction system, none recirculate
the air back into the laboratory.  There are, however, virology cabinets on
the market which are free standing and do recirculate the air back into the
laboratory and the person I spoke to did feel that they were perfectly
safe, provided they underwent proper safety checks on their filters by a
professional testing agency at regular intervals.  Filters can leak, they
can also be punctured.  Virologists are mainly concerned about being
infected by airborn droplets and this may be something quite different to
possible infection by cryostat vacuum systems.

Hopefully the message from Ian, and this one, will lead to useful comments
on this forum and lets hope the manufacturers come up with detailed
information too.

Jim.

Jim Hall,
MDA Equipment Evaluator,
Department of Histopathology,
University College London Hospitals,
Rockefeller Building,
University Street,
London, WC1E 6JJ.
Tel.No. 0171 209 6042
Fax 0171 387 3674