My first (and most important) tip would be to process only a few samples at
first. My first batch of embryos (E12-E18) I ran through the tissue
processor, came out looking like raisins.... shrunken and shrivelled. The
solution was to decrease the temperatures and times of your processing
program. I can't give specifics as this was quite a few years ago.

At my present job, I only submit my samples and the people in pathology run
them through their processor for me and so far I've had no problems (I'm
assuming they run a standard program).

As for sectioning, I've found it very helpful to moisten the face of the
block with 20% alcohol for about 30 seconds before taking 4 sections.
Apparently this reduces the amount of cracking in the section. The ribbon is
then floated on 20% alcohol before it is slipped into the waterbath. The
temperature of the water bath is quite high.... 45-50C, and I find that this
helps spread the sections quickly and evenly. Another thing I do is place a
piece of glass over the water bath to keep the humidity in.

Hope this helps.

Jen Robertson
Samuel Lunenfeld Research Institute
Mount Sinai Hospital
Toronto, Ontario

Subject: mouse embryos

Hi

I'm looking for some useful tips on doing paraffin on very late stage mouse
embryos (day 18.5) that must be "intact" - meaning that I cannot trim off
any skin to make fluid exchange easier.

Also, some useful paraffin tips on earlier stage embryos (day 9 and 10)
would be appreciated.

Thanks
Linda Prentice

Linda Prentice
Department of Anatomy
University of California San Francisco
513 Parnassus Ave
Room S-1343
San Francisco CA 94143-0452
Phone 415-476-1439
Fax 415-476-4845


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