Jacqueline,
I don't do as much GMA as I used to so these suggestions may not be the most
helpful. I always found that a few drops, number depending upon the size of
your water bath, of ammonium hydroxide always helped flatten and expand the
sections. I did this using a room temperature water bath. Also I found GMA
sections harder to keep flat and properly expanded the thicker they were
cut. We routinely cut GMA at 1-2 microns rather then 5. Hope these
suggestions or those from other Netters will help.

John Tarpley 15-2-B
Specialist Image Analysis & Immunohistochemistry
Amgen Inc
One Amgen Center Drive
Thousand Oaks, CA  91320

Views expressed are mine alone and do not represent the views of my employer


> ----------
> From: 	Jacqueline F. Webb[SMTP:jwebb@po.villanova.edu]
> Sent: 	Wednesday, August 04, 1999 2:42 PM
> To: 	histonet@pathology.swmed.edu
> Subject: 	Need help with GMA sectioning
> 
> Hope someone out there can help.
> 
> We have been sectioning fish heads (portions of large ones or whole small
> ones) for a study of sensory systems and swim bladder specializations in
> butterflyfish.  These fish have a very thick stratum compactum in their
> dermis, which is composed of fibrous collagen.  Infiltration has been good
> (over 2 days), translucent tissue is the result. We also use a bit of
> vacuum to get rid of bubbles. Polymerization is carried out in the frig
> for
> larger blocks because of rising temperatures.  Sections at 5 um are fine,
> but when we float them out on water (room temp or very warm) the plastic
> stretches, the internal soft tissues stretch, but the collagen in the
> dermis doesnt stretch. The result is ruffles radiating out from the tissue
> and folds in the internal tissues. Staining and subsequent drying does not
> change this situation.  This prevents any decent publishable photos from
> being taken at lower magnifications (which is essential).  The tissue (a
> marine fish) was fixed in 10% formalin in Seawater or in phosphate buffer
> and decalcified (with radiographic confirmation) by Cal-Ex (Fisher)
> overnight with 3-4 hours running tap water rinse.
> 
> HELP??
> 
> Jackie Webb
> Asst. Prof. Biology
> Villanova University
> 
> Jacqueline F. Webb
> Department of Biology
> Villanova University
> Villanova, PA  19085
> 610-519-7086 (office/lab)
> 610-519-7863 (FAX)
> jwebb@email.vill.edu
> 
> If you do not receive a reply to a message, or
> if your message is bounced, please send the message
> to me at:     jfwebb1999@aol.com
> 
> http://www.bio.villanova.edu/FACULTY/webb/jw1.HTM
> 
> 
>