Renee,
I process a lot of rodent tissue in my lab and don't have a problem with 
over processing. I have an old processor that doesn't use vacuum or heat 
during the processing and only some gentle swirling for agitation (Tissue 
Tek dip 'n dunker). This seems to be perfect for all the animal tissue that 
I process. My usual schedule is one hr in all stations - 2-70% ETOH, 1-80% 
ETOH, 2-95% ETOH, 3-100% ETOH, 2-Xylene, 2-Paraffin. I usually let the 
tissue set for a little longer in the last paraffin to make sure that it 
gets infiltrated well.
When I worked for a company that manufactured enclosed tissue processors we 
often had complaints that the tissue was coming out looking over processed. 
If they turned off the vacuum in some or most of the stations they had 
better results. Also if you have variable agitation - like a stirring 
mechanism that you can program for different speeds you might want to turn 
it down a notch or two.
Hope this helps.
Andi





At 08:19 AM 1/17/02 -0500, you wrote:

>Some people have asked to see my processing schedule  to help determine if 
>in fact our mouse tissue is being over processed.  After fixing for 48hrs 
>and then being held in 70% ethanol until processing(could be a few 
>weeks)  mouse tissues (about 3mm in size ) are processed by the following 
>schedule:
>
>70% ethanol              15min             Ambient 
>temperature          Vacuum     *all solution are also
>80% ethanol              15 min            Ambient 
>temperature          Vacuum       stirring.
>95% ethanol              20 min            Ambient temperature          Vacuum
>95% ethanol              30 min            Ambient temperature          Vacuum
>absolute ethanol        20 min            Ambient temperature          Vacuum
>absolute ethanol        30 min            Ambient temperature          Vacuum
>Xylene                      30 min            Ambient 
>temperature          Vacuum
>Xylene                      30min             Ambient 
>temperature          Vacuum
>Paraplast                 45 min            Ambient 
>temperature          Vacuum
>Paraplast                 45min             Ambient 
>temperature          Vacuum
>Paraplast                 45min             Ambient 
>temperature          Vacuum
>
>
>Thanks,
>Renee
>
>
>Renee Hoyle-Thacker
>CIIT Centers for Health Research
>6 Davis Dr.
>Research Triangle Park NC 27709
>Voice: (919) 558-1322
>
>
>

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