RE: Cutting paraffin blocks in a cryostat

From:Gayle Callis <>

One of the joys of a Cryocut 1850 is being able to use the older,
waffleweave or grooved metal chucks.  Shandon still sells these.  We just
shorten the stem to match stem length of a Leica cryostat chuck and
actually prefer these to the shallow grooves of the cryostat chuck for
frozen work.  Not as pricey either.  

You will have to do an old fashioned heat mounting onto chuck. 

You heat chuck in a flame, hold stem with a sturdy forceps, press the back
of paraffin block into the hot grooves to melt into paraffin, maintain
steady pressure on block/chuck, and plunge everything into cold water for
instant cooling. With practice you will not overheat the chuck, or paraffin
"spits" everywhere! 

This permits chuck "waffles" or grooves to hold paraffin block firmly.  I
would try warming the cryostat a bit, - 15C or so.  Probably will work, but
it will make a mess in the cryostat unless you are spiffy clean about

At 12:14 PM 5/1/01 +0930, you wrote:
>Dear Andrew, I guess it's possible but I am not sure how you will get
>paraffin infiltrated and supported tissue to attach and hold on to a
>cryostat chuck. I am assuming that the Leica crostat has the round chuck
>which drops into a round sleeve and locks tight. Although a cryostat may
>look like a fridge with a microtome in it they are each designed with a
>purpose in mind. The temperature will make it hard to trim, hard to
>ribbon (if not impossible). Do you have access to a water-bath to float
>out your sections? etc
>It would be a whole lot easier to talk to the staff at the Med Lab Sc
>school and borrow some time on one of there microtomes. If that fails
>I'm sure one of the local histo labs would rip off a few sections for
>you. David.
>David Taylor
>Laboratory Manager
>Drs King & Mower
>Adelaide, Australia
>-----Original Message-----
>From: Andrew Gray []
>Sent: Tuesday, 1 May 2001 10:20
>Subject: Cutting paraffin blocks in a cryostat
>Hello Histonetters,
>A question from a newbie to the list.   I was wondering if anyone knew
>if it is possible to cut paraffin blocks in a cryostat.   I have access
>to a Leica CM 1850 cryostat and I wish to examine some soft tissues of
>rats.   Paraffin is preferable for handling and storage reasons, but I
>don't have access to a standard microtome.   The mechanics of a cryostat
>seem essentially the same, but I was wondering about the practicalities
>of using it in this way (e.g. the appropriateness of the blade, holding
>the block in position with the adhesive, temperature etc.).
>Thanks in advance,
>Andrew Gray
>B.Pharm, B.PharmSc(Hons)
>Ph.D student
>Victorian College of Pharmacy
>Melbourne, Australia
Gayle Callis
Histopathology Supervisor
Veterinary Molecular Biology
Montana State University - Bozeman
Bozeman MT 59717-3610

406 994-6367
404 994-4303 (FAX)

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