Two possibilities are:

- A small amount of eosin added to the last absolute alcohol in the
processing cycle. The specimens will pick up the stain and then move
directly into xylene so that the eosin has no opportunity to wash out.  I
keep a small vial of very strong eosin (almost saturated) dissolved in
absolute alcohol for this purpose.  A few drops of this "superconcentrate"
added to the final alcohol is sufficient to tint small specimens pink.

- Mark the specimens with India Ink prior to processing. This is in fact a
particulate material since it is a suspension of very fine carbon particles,
not a true solution. I use this often, for example to distinguish between
the proximal and distal ends of a vessel or nerve. Blot the specimen on
paper towel, so that it is damp but not too wet. I use a wooden applicator
stick to apply the ink.  Dip the stick into the ink, blot it to remove
excess ink, then touch it to the specimen. If there isn't a lot of liquid on
the specimen and there isn't a lot of ink on the stick, the ink can be
applied quite precisely.  The ink doesn't penetrate into the tissue, so in
the finished sections it appears as a black line along the marked surface
only.  The carbon is chemically inert, and is resistant to all solvents
normally used in processing histological specimens.

Paul M.



> ----------
> From: 	histonet-bounces@lists.utsouthwestern.edu on behalf of ze'ev
> silverman
> Sent: 	Tuesday, July 19, 2005 1:31 AM
> To: 	Histonet@pathology.swmed.edu
> Subject: 	[Histonet] transparent tissue
> 
> We are trying to embed 300 micron thick, mouse olfactory bulb explants. 
> The explants are about 3 mm diameter and become transparent following 
> exposure to xylene, making it very difficult to orient them. Does 
> anyone know how we might lightly stain or label the tissue, perhaps by 
> some particulate material? Different stains and materials we have tried 
> have not survived the ethanol or xylene steps.
> 
> Thanks,  ZS
> 
> 
> Ze'ev Silverman, Ph.D.
> Zlotowski Center for Neuroscience
> Dept. of Morphology
> Faculty of Health Sciences
> P.O. Box 653
> Beer Sheva 84105
> Israel
> 
> 972 8 647-7307 (office)
>          8 647-7304 (lab)
>          8 647-7627 (fax)
> http://medic.bgu.ac.il/brain
> _______________________________________________
> Histonet mailing list
> Histonet@lists.utsouthwestern.edu
> http://lists.utsouthwestern.edu/mailman/listinfo/histonet
> 
> 

_______________________________________________
Histonet mailing list
Histonet@lists.utsouthwestern.edu
http://lists.utsouthwestern.edu/mailman/listinfo/histonet