Dear Karen,
you may find that a lower concentration of Sucrose is required at least
initially because of the difference in S.G. Once it has sunk you can
increase the concentration. But to start off, place the brain in the 30 %
solution and slowly ad and mix deionised water until the top of the sample
just clears the surface of the liquid; check every 6-12 hours to see if has
sunk, if has sunk add sat. sucrose solution to mixture until brain just
floats, continue adjustment until you reach a 30% conc. (keep a beaker of
30% stock at one side to test brain for floatation)
Regards Mike
-----Original Message-----
From: Karen D. Larison <LARISONK@UONEURO.uoregon.edu>
To: HistoNet@Pathology.swmed.edu <HistoNet@Pathology.swmed.edu>
Date: Friday, 8 January 1999 5:34
Subject: that sinking feeling


>Hello histonetters,
>
>I have a graduate student who has done some physiology on a monkey brain.
He
>now wants to cut cryosections of this brain (electrode tracks have been
marked
>with DiI), and has put a portion of the brain (maybe a 3-4" cube) in 30%
>sucrose and is waiting patiently for it to sink.  He's been waiting for
over a
>week now.  My question is:  Do all brains sink in 30% sucrose, or are the
>brains of "higher" organism too myelin-rich to sink?  Any responses will be
>appreciated.  He defends in about 3 weeks, and is a bit nervous as this
work
>represents his last piece of supporting data.
>
>Thanks for all your help.
>
>Karen Larison - University of Oregon
>
>
>
>