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 ----------------------------------------------------------------------- Joel Lowy The usual disclaimers. Physiology Dept. AFRRI, 8901 Wisconsin Ave., Bethesda, MD 20889-5603, USA [log in to unmask] 301-295-1790 FAX 301-295-0313 -----------------------------------------------------------------------