Cryostat problems

From:Gayle Callis <>

You wrote:

I have been having some touble while sectioning fresh frozen tissue this 
week. I have tried several different things to rememdy, nothing working. Has 
anyone else experienced these problems? And how where they resolved. 
1. The tissue is splitting in half, all the way across the face of the block. 
Not the up and down which would indicate to move the blade. 
2. Bad problem with thick and thin sections. I've sprayed the tissue to bring 
down the temp and make it colder. 
3. Also when facing the block I have noticed, that there are ripples in the 
4. Alot of Chatter, and the venetian blind. 
So anyone out there can help!!!!! I appreciate it!!! Thank -you .. 

Sounds like the microtome is out of adjustment. 
Check all your settings on knife holder for starters.  Tight?  

Knife angle may need to be tweaked, be sure to mark optimal setting on
holder, so that when holder is placed back into chamber, you have it in the
same position/angle each time.  Clean the holder, under, around all parts
that hold the device down.   

Make sure the block is mounted onto chuck with enough OCT, no spaces under
the tissue, or edges, these can be filled in to insure good holding. 

Our major thick thin problem is due to the following:

Also, ice crystal buildup in cryostat moving parts will cause the
thick/thin problem.  You did not say what cryostat you have.  If it is a
Cryocut 1800 or 1850, defrost, take the micrtome out and make sure it is
totally dry both the chamber and microtome (do this with every cleaning).
I was told to spray the little solenoid contacts or whatever they are (head
must be in up position to see these) on the left side of microtome (when
out of the chamber, thawed and dried) with a very fine spray of 100%
ethanol, to insure they are truly dry.  Let these stand for a while to dry
again, a little fan helps. 

Your microtome feed may be off.  Adequate lubrication (it doesn't take
much, depending on cryostat?)  

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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