Re: Alternate thick-thin cryostat sections

From:Ryan Blair Rountree

I have also had this problem with my machine.  Two reasons we've come up
with are 1) something is loose somewhere.  If the knife, knife holder,
block, or microtome head isn't nice and snug, this will definately do it.
Our microtome head as several alan-wrench-screws that can be tightened so
that when you lock the head in the correct orientation it is held very
tightly in place.  Every few months, the head on our machine gets loose,
even to the point where you can readily move it by hand in the lock
position. If you unscrew the long screw that holds the block in
place, the face of the microtome head comes off and you can easily tighten
2 screws for this.  There are others as well though, and you should really
have this done by your service rep.  Just make sure that everything you
can tighten starts tight and stays tight throughout the run!
2) There can be scratches on the "telescoping arm" that extends the
microtome head with each section.  If these are bad enough, the head can
catch on them occasionally as it advances.  This however is a major
repair.  It might cost $2-3000!  In our case there were scratches here and
since we had a service contract it was no big deal to repair.  But the
price of the repair was basically the price of the service contract!
Anyway, I haven't been having this problem any more, but I think the main
reason is that everything is very tight and stable now.  Start with that!

 On Fri, 25 Oct 2002, Phil
Bergin wrote:

> Hi,
>
>
>
> We have a Leica CM1800 cryostat which is great and serviced regularly
> with no problems.  All of our biopsies are embedded in OCT and we
> generally section at about 8 microns in thickness.  We often get
> sections which come out with every other section being thin, followed by
> one which is apparently the correct thickness, followed by another thin
> section and so on.  This doesn’t happen on every biopsy, but on enough
> for it to be a regular occurrence.  Is this normal?  Or is it something
> to do with the way the specimens are being prepared?  According to our
> service rep it is something that just happens and should be ignored.
>
>
>
> Thanks for any advice,
>
>
>
> Phil
>
>
>
> -----------------------------------------------------------------
>
>
>
> Philip Bergin
>
> Göteborg University
>
> Department of Medical Microbiology and Immunology
>
> Box 435, SE-405 30 Göteborg, Sweden
>
> Phone: +46-31-3424727
>
> Fax: +46-31-826976
>
>
>
>
>

Ryan Rountree
Department of Developmental Biology
B301, Beckman center
279 Campus Drive
Stanford, CA 94305
(650) 725-7599
Fax: (650) 725-7739


 

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