Hi Gayle,
We have done about the same thing as you described.
Cells (attached to glass slide) or tissue sections were immersed in=20
chloroform for 5 min (defatting - we are working with atherosclerotic=20
material!!) and air-dried. Next, slides were fixed using home-made 4% PFA 
for 5 minutes and washed (3x5 min) with PBS. After a brief rinse with=20
distilled water (2 min) slides were and air-dried under a fan. Stored at 
-80°C (as described in previous mail) until use.
This procedure worked fine for both IHC and ISH. Morphology was good.

Chris van der Loos
Academic Medical Center H0-120
Dept. of Cardiovascular Pathology
Meibergdreef 9
NL-1105 AZ Amsterdam
The Netherlands

Gayle Callis wrote:

 >Date: 10 Dec 2002 14:16:06 -0600
 >From: Gayle Callis 
 >Subject: Re: Storage of frozen sections
 >A technic put out by Pharmingen on formalin or PFA fixed cells, probably
 >works for tissue sections - fix in formalin, rinse with PBS X 2 changes,
 >immerse slides in 1% BSA (Jackson has protease/immunglobulin free BSA) for
 >10 min, remove slides but DO NOT RINSE, just air dry, and store at -80C.
 >I assume BSA coats section, providing some "protein carrier barrier" from
 >freezer atmosphere.
 >Gayle Callis