Paul
I coat slides with celloidin for immunos here with little problem.  I
find some of the higher pH retrieval methods cause lose of tissue so
need the coating.  I just extend the time in each of the reagents by
half and get nice staining.
Mark Elliott
iCAPTURE Centre
Vancouver, BC

>>> "Monfils, Paul"  10/05/06 11:16 AM >>>
There is the venerable old technique, seldom used today, of coating
the
slide with celloidin, also known as parlodion. The technique isn't used
much
today, partially because electrostatically charged slides have solved
many
of the adherence problems, and partially because the technique
requires
ethyl ether, which is forbidden by many institutions today because of
its
extreme flammability.  But what we used to do is make up a solution of
celloidin in 1:1 ethanol/ethyl ether, deparaffinize the slides through
absolute alcohol, immerse them in the celloidin solution for about a
minute,
then transfer them to 80% ethanol for a few minutes to harden the
celloidin
film. After that they can be rehydrated and stained as usual. The
celloidin
forms a continuous semipermeable membrane over the entire slide and
tissue,
which physically holds the section in place during staining. Most dye
molecules can pass through the celloidin membrane and stain the
tissue.
Antibody and enzyme molecules are too large to pass through the
membrane, so
techniques involving them cannot be done.  Some standard histochemical
procedures will stain the celloidin as well as the tissue, but this is
not
usually a problem because during the final dehydration prior to
coverslipping, the xylene will dissolve away the celloidin.  Many years
ago
we used this technique particularly for silver stains involving
ammonia,
since the ammonia would attack the gelatin we used as a section
adhesive,
and cause the sections to fall off the slides.

> ----------
> From: 	histonet-bounces@lists.utsouthwestern.edu on behalf of
John
> Baker
> Sent: 	Thursday, October 5, 2006 9:00 AM
> To: 	Histonet
> Subject: 	[Histonet] tissue coming off slides
> 
> Hi All,  A group I work with just came to ask if there was a way of 
> keeping frozen tissue sections from coming off a slide?  It seems
there 
> technician used uncoated/regular slides to mount 100's of sections. 

> The tissues were embedded in OCT and cut at 5 microns but of course
are 
> sliding off during any staining procedure.  Is there a protocol of
any 
> sort to coat the slides after the fact to retain the sections through

> staining?  I at least suggested they stain flat.  Any suggestions are

> appreciated.  John
> 
> John A. Baker
> The University of Michigan
> Orthopaedic Research Laboratories
> Histology Unit
> 109 Zina Pitcher Place, 2218 BSRB
> Ann Arbor, MI 48109-2200
> 734-936-1635
> 
> 
> _______________________________________________
> Histonet mailing list
> Histonet@lists.utsouthwestern.edu 
> http://lists.utsouthwestern.edu/mailman/listinfo/histonet 
> 
> 




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