RE: [Histonet] curling sections

From:"Alan Bright"

I would like to explain a few points that maybe useful to those
experiencing problems on the Histonet recently with 'Curling sections'
and those who may in the future.

There have been quite a number of you mentioning this problem on the
Histonet recently, with a range of cryostats from different
manufacturers.  One of these was manufactured by us, where our user had
no problems for years, then the problem started, the outcome was that a
new cryostat from another manufacturer was purchased and installed.
After 1 month the same problem re-occurred. The sales representative
from the company that supplied the new cryostat  thought it had to be in
the environment (I assume it was not the first time this sales rep had
encountered this problem), and the cryostat was moved to a small room
with a dehumidifier running constantly.  The outcome was that now the
sections are fine and not curling.

The purpose of this email is to save others from falling into this
predicament and saving them from a lot of wasted time/effort and great

The cryostat microtome chamber is in fact a dehumidifier, but if routine
automatic defrosting is not carried out and the cooling fins become
blocked then it becomes inefficient in dehumidifying and it looks like
this could cause the above symptoms. I had no answer to this problem
when I first looked into it as this was the first reported case of this
problem on one of our cryostats in almost 50 years. This was probably
due to the highly efficient refrigeration system we install also coupled
with our independent specimen temperature control that is supplied to
most of our brain sectioning users, allowing them to maintain a much
lower chamber, knife and anti-roll plate temperature while controlling
the specimen independently at the correct temperature. With the added
benefit that the colder chamber temperature acts as an even more
efficient dehumidifier. But even with or without these features  it is
most important to carry out a regular automatic defrost regime, more so
in high humidity locations.  

Best Regards

Alan Bright

Bright Instrument Co.Ltd.
St Margaret's Way
PE29 6EU

Tel No:+44 (0)1480 454528
Fax No:+44 (0)1480 456031
Web Site:

-----Original Message-----
From: Kathleen Spencer [] 
Sent: 05 November 2004 22:54
Subject: [Histonet] curling sections

Hi Everyone,

Several months ago I sent out a cry for help because my perfused frozen 
20u sections had started curling up in tight little rolls in the 
buffer, which made it impossible to do IHC on them. We tried EVERYTHING 
and finally bought a new cryostat, a Leica 1850. It worked well for one 
month and then the curling started again. The Leica rep thought it had 
to be the environment and although it sounded crazy, we went with that.

So it was the humidity!!!!!!!!!!!!

We have moved the cryostat to a small room with a dehumidifier running 
constantly. The water catcher resevoir was full after 24 hrs! We were 
amazed and dumbfounded. So Memphis is the humidity capital of the world 
I guess.

Who would have thought?

My sections are nice and flat and beautiful now. I want to thank 
everyone that tried to help and as I promised, am letting you all know 
that it was the HUMIDITY!
I also put a large beaker of EtOH in the cryostat, and by the way, I 
love the Leica.
It is now in a small room in a different building with a dehumidifier 
running constantly.


Kathleen Spencer HT (ASCP)
Lab Manager/LCM Supervisor

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