2/14/97
SEM and XRF analysis. Not being pathologists and having no prior
experience with biological tissue samples, we are concerned about
potential health risks from handling this material. The samples were
collected and lyophilized at least 20 years ago and have been in storage
all this time. Sample preparation for the XRF analysis will require
pulverizing the material with mortar and pestle and depositing this fine
dust onto filter subtrates for analysis with the potential for exposure to
or inhalation of the dust. Our safety officer doesn't know whether any
viruses or bacteria could still be viable in any of these samples, and is
not sure what level of safety precautions are required: e.g., Should the
work be done in a hood certified for biohazard work or is this overkill?
Should the lab technician be inoculated against hepatitis B? Moon suits
and hazard pay? (I'm joking, but maybe I shouldn't be). The histories of
the tissue donors are available if that would be a determining factor but I
don't think many died of an infectious disease.
Thanks for any comments and suggestions.
Bob Willis
ManTech Environmental
email: Willis.robert@epamail.epa.gov
tissue. If stored properly , lyophilized microbes can survive a long time.
When I was a postdoc we got live cultures from lyophilized samples that
were under vacuum and stored at 4 degrees C for over 40 years. This was not
an exception but rather the rule. So if these samples have not been fixed
or other denatured or sterilized, I would be careful.
G.W. Erdos, Ph.D. Phone: 352-392-1295
Scientific Director,
ICBR Electron Microscopy Core Lab
218 Carr Hall Fax: 352-846-0251
University of Florida E-mail: gwe@biotech.ufl.edu
Gainesville, FL 32611 http://www.biotech.ufl.edu/~emcl/
Home of the #1 Gators
> SEM and XRF analysis. Not being pathologists and having no prior
> experience with biological tissue samples, we are concerned about
> potential health risks from handling this material. The samples were
> collected and lyophilized at least 20 years ago and have been in storage
> all this time. Sample preparation for the XRF analysis will require
> pulverizing the material with mortar and pestle and depositing this fine
> dust onto filter subtrates for analysis with the potential for exposure to
> or inhalation of the dust. Our safety officer doesn't know whether any
> viruses or bacteria could still be viable in any of these samples,
POSSIBLY
and is not sure what level of safety precautions are required: e.g.,
Should the
> work be done in a hood certified for biohazard work or is this overkill?
DEFINITELY. NOT OVERKILL.
> Should the lab technician be inoculated against hepatitis B?
JUST DON'T STAB YOURSELF WITH CONTAMINATED FORCEPS.
Moon suits
> and hazard pay? (I'm joking, but maybe I shouldn't be). The histories of
> the tissue donors are available if that would be a determining factor but I
> don't think many died of an infectious disease.
>
I'D WORRY MORE ABOUT TB THAN HEPATITIS. TB IS VERY INFECTIOUS IN
AEROSOLS AND DUST. I'D MAKE SURE NONE OF THE DUST ESCAPES, OR FIX IT
SOMEHOW, IF YOU CAN KEEP FROM CONTAMINATING YOUR ANALYSIS WITH SOMETHING
THAT WOULD RUIN YOUR TEST. HOW ABOUT OSMIUM VAPOR??? JUST DON'T TAKE ANY
CHANCES. REGULATIONS NOW REQUIRE THAT YOU TREAT ALL TISSUES AND
BODLIY FLUIDS AS THOUGH THEY MAY BE INFECTIOUS.
Sara E. Miller, Ph. D.
P. O. Box 3020
Duke University Medical Center
Durham, NC 27710
Ph: 919 684-3452
FAX: 919 684-8735
saram@acpub.duke.edu
Several have commented to me that putting a virus in the electron beam,
which has similarities to putting it at the centre of a small nuclear
explosion, is probably the only sure way to kill a virus. And until that
point, they always regard a virus as 'alive', whatever chemicals it may
have gone through.
Regards,
Larry Stoter
LPS@teknesis.demon.co.uk
There are many ways of killing viruses, besides electron beams; however,
I wouldn't assume that the electron beam hits every nm of space on the
sample, and hence, kills everything that went into the scope!!>
Furthermore, the dust from grinding specimen flying around while you're
preparing it for EM could be infectious. See my earlier comment on TB.
Sara
Sara E. Miller, Ph. D.
P. O. Box 3020
Duke University Medical Center
Durham, NC 27710
Ph: 919 684-3452
FAX: 919 684-8735
saram@acpub.duke.edu
the specimens may very well still be viable. At least you don't have to
worry too much about HIV- but I wouldn't have been worried about that
anyways- it's not known to be transmissible by inhalation. My major concern
would be tuberculosis. Most of the bacteria and viruses that might lurk in
old lungs are unlikely to cause serious disease in a person with an intact
immune system. TB can cause a serious infection despite a good immune
system and infection can be established with a very small dose.
>Sample preparation for the XRF analysis will require
>pulverizing the material with mortar and pestle and depositing this fine
>dust onto filter subtrates for analysis with the potential for exposure to
>or inhalation of the dust.
Now I'm really concerned about TB. The pulverization is a perfect way to
get aerosols into your lungs.
>Our safety officer doesn't know whether any
>viruses or bacteria could still be viable in any of these samples, and is
>not sure what level of safety precautions are required: e.g., Should the
>work be done in a hood certified for biohazard work or is this overkill?
>Should the lab technician be inoculated against hepatitis B? Moon suits
>and hazard pay? (I'm joking, but maybe I shouldn't be).
Doing the work in a hood is not a bad idea. You could probably get away
with having everyone in the room wear a respirator with a filter fine
enough to filter out TB ("N95" respirator). These are available as powered
positive air pressure units or as disposable non-powered units. A surgical
face mask would not be sufficient. Hepatitis B vaccination shouldn't be
necessary, it's another bug that probably isn't transmitted by inhalation,
but the vaccine is low risk and inexpensive so why not?
>The histories of
>the tissue donors are available if that would be a determining factor but I
>don't think many died of an infectious disease.
You might want to look at occupational histories. Some groups, e.g. miners,
had higher incidence of TB.
I hope this helps.
Leon
--
Leon A. Metlay, M.D.,Associate Professor of Pathology and Laboratory Medicine
University of Rochester Medical Center Phone: (716) 275-5691
P.O. Box 626 Fax: (716) 273-1027
Rochester, NY 14642 lmetlay@acu.pathology.rochester.edu
http://www.urmc.rochester.edu/smd/pathres/URPLM.html
the tissue out on the open bench will cause fine particles to fly all over
the lab with every air current, contaminating everything and everybody in
the lab. I would use a biohazard hood.
Lesley Weston
Oral Biology
University of British Columbia
Vancouver, B.C., Canada
lesley@unixg.ubc.ca
environmental surfaces. If you have a hood use it. On the other hand, I
wouldn't be really concerned about infectious particles on environmental
surfaces. The bugs I'm more concerned about spread by inhalation, not by
skin contact. If you don't want to risk bringing something home with you, a
surgical gown or similar smock can be used to protect your clothing.
Leon A. Metlay, M.D.,Associate Professor of Pathology and Laboratory Medicine
University of Rochester Medical Center Phone: (716) 275-5691
P.O. Box 626 Fax: (716) 273-1027
Rochester, NY 14642 lmetlay@acu.pathology.rochester.edu
http://www.urmc.rochester.edu/smd/pathres/URPLM.html
paraffin and then cut slices which could be attached to an inert substrate,
deparaffinized and examined in the SEM. This would keep aerosols to a
minimum - if not eliminate them entirely by encapsulation in paraffin
during the critical cutting stage.
John J. Bozzola, Ph.D., Director
Center for Electron Microscopy
Neckers Building, Room 146 - B Wing
Southern Illinois University
Carbondale, IL 62901-4402
U.S.A.
Phone: 618-453-3730
Fax: 618-453-2665
Email: bozzola@siu.edu
Web: http://www.siu.edu/departments/shops/cem.html