At 14:36 24/05/01 -0400, vous avez écrit:
>A question for the gurus of Histology.
>
>Many years ago (and I emphasize many) the lab I trained in used a technique
>for post treating paraffin sections to keep them on the slide through some
>of the silver staining techniques.  It involved dipping the mounted,
>deparaffinized slides in a mixture containing celloidin.  Does this ring a
>bell out there, and if so do you remember the concoction and procedure
>details?

I did this many years ago for the Glees silver staining. Take the 
deparafinized sections down to 95% ethanol and then into 1% celloidin in a=20
50/50 ethanol/ether mix for 2 minutes. Drain and leave the solvents to 
evaporate. Then go back to 95% ethanol for 5 minutes to harden the 
celloidin and stain.
After the staining the celloidin is eliminated in the 100% ethanol baths. 
We did this not to prevent the sections from falling of, but to eliminate 
silver precipitates over the slides. With the Glees technique there is 
often a cloudy silver precipitate all over the slide. Because this is a 
direct deposit from the staining solution, it deposits on the celloidin 
film (not in the section as the stain) and goes off when the celloidin is 
redissolved.

Two caveats on the technique. The celloidin film is impermeable to some 
stain involving larger stain molecules, and particularly antibodies. Thus 
for ICC this is definitely a No-No.
Also, celloidin is flammable and even explosive, and it is dissolved in 
ethanol-ETHER, which certainly does not improve this problem. Thus be 
extremely carefull with this mixture. Especially in the States, check with=20
your security officer on the handling and disposal of this reagent.

Good luck

Paul
                                                                         -=3D-
                                                                        (o -) O
==========================3D=====oOo==(_)==OOo=============3D================
Paul Klosen, PhD
CNRS UMR 7518 Neurobiologie des Fonctions Rythmiques et Saisonnieres
Universite Louis Pasteur  12, rue de l'Universite
F-67000 Strasbourg, FRANCE
Tel. 03.90.24.05.01  Fax. 03.90.24.05.28
========================klosen@neurochem.u-strasbg.fr==================3D=======