Re: CJD question, frozen sections
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|From:||LuAnn Anderson <email@example.com>|
Responding to the message of <firstname.lastname@example.org>
from "R.Wadley" <email@example.com>:
While nothing is 100% effective against CJD, formic acid treatment has been
found to be about 80% effective in deactivating the protein. Better than 0%
with frozen sections. As I have stated, there are distinct symptoms and test
results that point dirctly to CJD as a possibility and this is a very effective
screening technique. Most Neurosurgeons and hospitals DO NOT allow biopsies to
be done on these patients because of the inability to completely decontaminate
the OR suite and surgical instruments and this has been a known source of
transmission. If they won't do biopsies, what's the point of doing frozens???
> members.aol.com/larmstr853/cjdvoice/cjdvoice.htm. Check out this very
reputable website, "CJD voice", Read some of the case histories and see kof this
is really something you want to Chance taking home to your family.
> As far as I understand CJD remains virtually unaffected by fixation &
> processing, so why is there a difference between a frozen & a paraffin.
> One of the classic experiments into scrapie (Ovine CJD) is to take a
> sample, fix it, process it, block it out, section, stain & coverslip it,
> then scrape it off the slide (after clearing back to water) & use the
> macerated section to infect a healthy sheep.
> Pathology laboratories whether diagnostic or research, deal with both
> hazardous samples & hazardous reagents. There are procedures to protect
> scientists & technicians working in those laboratories. Diagnostic
> laboratories have an obligation to treat all patient samples equally. To
> actively disciminate against individuals who may have or are suspected to
> have a particular infectious agent is unethical. Research can have the
> luxury of determining what sort of sample they will deal with, within
> limits. My lab is a semi commercial unit located in a university providing
> research resources, I will not run human samples unless they have been
> screened for HIV & the various hepatitis viruses. However, when my flow
> cytometer is modified to remove the possibility of infection to the
> operator by aerosols, then, under appropriate conditions, there may be
> scope to run & more importantly sort infected samples.
> By not performing certain techniques on known infectious or contaminated
> samples simply makes lab staff over confident. My first experience of lab
> practicum was in a haematology lab in the late 80's. A known, tagged HIV
> sample came in. The whole lab was cleared, the staff member assigned to
> deal with the sample was gowned, masked, wore eye protection, & was double
> gloved. There was a person on the door to prevent entry to the lab. Yet
> this was a lab that dealt with hundreds of samples per day, statisticly
> they probably had at least one HIV positive sample per week. But because
> they were unknown no special precautions were taken. In this case being
> paranoid probably put more people at risk than instituting good laboratory
> practice. "Normal" safety procedures in that lab was gowns & single
> gloves, although occassionally the gloves were optional.
> I am not advocating that laboratory staff should put themselves at risk.
> I'm saying every sample is potentially infectious and/or hazardous & no
> samples should be discriminated aainst just because you happen to suspect
> they are infected. Try a simple experiment, randomly sample the frozens
> you do, check back to the patient files, I think you would be very
> surprised at the number of infectious cases you routinely cut without all
> this trauma you associate with known infectious cases.
> Rob W.
> At 16:07 03/15/2000 -0600, you wrote:
> >If the CDC states frozen sections should not be performed on known CJD
> >specimens I think that in itself is a valid argument. Afterall, 24 hours
> >is not long to wait for 'permanent' sections to be obtained.
> >And I doubt waiting 24 hours changes the protocol for treatment outlook for
> >these patients.
> R. Wadley, B.App.Sc. M.L.S, Grad.Dip.Sc.MM
> Laboratory Manager
> Cellular Analysis Facility
> School of Microbiology & Immunology
> UNSW, New South Wales, Australia, 2052
> Ph (BH) +61 (2) 9385 3517
> Ph (AH) +61 (2) 9555 1239
> Fax +61 (2) 9385 1591
> E-mail firstname.lastname@example.org
> www http://www.micro.unsw.edu.au/caf.html
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