Thanks Gayle,

I have actually been to Pathology Innovations and tried the brush technique,
and done correctly it does prevent tissue from rolling, at least as the
front edge comes off the block.  Often, however, the tissue will roll from
the back edge once it detaches.  Not always, but the nature of the tissue
(really thin) means that every section counts.  I may start trying it again,
however.  Also, you kinda lost me on the angles bit.  I counted 6 numbers
and none of them seem to add up :)  We use a low profile 'razor' blade and I
take the 0deg mark to be 0deg.  I set it to 3-4deg and 10um sections come
off flat (provided, of course, that the anti-roll plate is positioned
correctly).  Well, actually sometimes a bit wavy, but at least not curled
into a tube.  More or less angle and they curl.  It sounds like you get good
results with a greater angle, and others have called for less.  This seems
to be one of those indeterminate situations that depends more on what works
in a given setting for a specific tissue than what is correct or incorrect.
Gotta love science . . .

Ion




On 10/2/06, Gayle Callis  wrote:
>
> Ion,
>
> We have three 1850's and it is possible blade angles can be a bit
> different
> for thicker sections, the different types of blades one uses (high versus
> low profile) and also differences between different blade
> manufacturers.  Compression generally is NOT good, as it is hard to get
> the
> section flat once it is compressed and then have it be flat on a
> slide.  When doing the brush technic, use a sable brush #1 or #2, and make
> sure the tissue is surrounded by some OCT so you can grasp the frozen OCT
> gently instead of the tissue.  It is possible to use brush on unembedded
> tissues but you can't be a Picasso (actually brushing/touching the tissue)
> but rather let a few bristles guide the section onto the knife holder.  Go
> to Pathology Innovations website and watch Dr. Peters use the brush
> technic, he does it as well as anyone around.   I haven't used an antiroll
> device for years with exception of 50 um prefixed tongue - sometimes I
> have
> to use it.  We set our blade angle just one mark or 6 towards the 10 mark,
> 5 being the middle.  This would be an 11  to 12 degree angle.  5 to us
> means 10 degrees, and I must admit, angles are sometimes hard to
> understand
> from one cryostat to the next.
>
> Your Leica representatives, often locally or even experts in their main
> office, can be of help too.
>   mari.ann.mailhiot@leica-microsystems.com or
> jan.minshew@leica-microsystems.com are two ladies who will steer you in
> the
> right direction, both are experts at microtomy/cryomicrotomy and sell
> Leica
> 1850's.
>
> Good luck on your dilemma
>
> Gayle Callis
> MT,HT,HTL(ASCP)
> Research Histopathology Supervisor
> Veterinary Molecular Biology
> Montana State University - Bozeman
> PO Box 173610
> Bozeman MT 59717-3610
> 406 994-6367
> 406 994-4303 (FAX)
>
>
>
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