Dear Fellow Microscopists:
 
I am considering puchase of a new controlled temperature bath/chamber for
my Zeiss IM 35. I would like comments on current commercial systems from
other users. My requirements are to have or retrofit for both static and
perfused operation. Ideally I would like to hold both above (generally
37 deg C) and below ambient. My 80% solution is to hold at 37 only. Rapid
changes in temperature also nice, but examining various commercial systems
over the none I know of are much quicker that 1-5 minutes for a 30-40 degree
change (say ambient or sub to 37). I've solved the need for faster temperature
changes by constructing my own which work reasonable well.  The reason
for considering a commercial system is realabilty (fewer leaks) and ease of
operation for less knowledgable/skilled users. I am familar with the
product literature for many of the commercial systems including:
Nicholson Inst., Medical Systems, Warner Instruments, Biophysica Tech.,
Bioptechs Inc. and 20/20 Tech.
 
Comments welcome especially on the following re: actual use. I've done
the following as quetions - feel free to delete most of message. Can
summarize/forward if others interested:
 
Chamber type/Manufaturer:
 
Period of use:
 
Application:
 
1. Is the temp over the objective really 37 ? Are objective heaters really
needed?
 
My very limited experience is that in perfused systems are OK
- but static systems high temperatures at edge which is heated must
be non-physiological - to obtain 37 right above objective (oil or water) since
acts as heat sink - so moving to another field may not be possible as
cells already cooked elsewhere in chamber.
 
2. Can different objectives readily be changed/accomidated?
 
Sleeves that fit over the objective seem less that ideal - but I've not
used them - does one need essential one for every objective or is changing
them no problem.
 
3.  Can the newer larger diameter objectives be accomidated?
 
This seems to be a major design problem - if the chamber surface is big
enough for new objectives then edge heating is a problem and often
"specialized" - ie glass sizes only available from the manufacturer are
necessary and potentially a substail cost and long term maintance problem.
 
4. Additional comments:
 
 
Thanks in advance.
 
Joel Lowy
 
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Joel Lowy                               The usual disclaimers.
Physiology Dept.
AFRRI, 8901 Wisconsin Ave., Bethesda, MD 20889-5603, USA
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301-295-1790  FAX 301-295-0313
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