Molecular Probes carries silicone isolators for just this purpose.  The
link below describes a 20 mm diameter, 1 mm thick isolator, but other sizes
are available.  They are probably more expensive that the plastic
reinforcements, but they are reusable.

http://www.probes.com/servlets/product?region=USA&item=18175

Jill Hendrickson
Molecular Biology Product Manager
Molecular Probes, Inc.

David Driver wrote:

> greetings,
>
> our lab has been using round, plastic reinforcements--typically used to
> reinforce three-hole-punched papers in a binder, bought in an office
> supply store--as a reservoir to hold our staining volume in place.
> this has worked fine for mouse lymph node sections, but they are much
> too small to use for mouse spleen sections.
>
> does anyone out there know of a larger alternative that's
> available--something like a jumbo-reinforcement?
>
> thanks,
> david
>
> __________________________
> David Driver
> Department of Immunology
> Box 3010
> Duke University Medical Center
> Durham, NC  27707
> 919.613.7822
> [log in to unmask]
> _________________________________

--
Jill Hendrickson
Molecular Biology Product Manager
Molecular Probes, Inc.
Phone:  541-465-8356
Fax:    541-465-4593