[Histonet] Hardening very soft brains

Steven E. Slap siksik03 <@t> comcast.net
Fri Dec 5 13:25:48 CST 2003

Hi HistoNetters

Kok and Boon describe a technique, on pp. 116-118 of the newest 
edition of their book, which is a combination of microwave 
stabilization in saline (two steps) and two fixation steps (one 
"soaking step", on the bench, in 10% NBF, and one true microwave 
fixation step, also in 10% NBF).  Thsi technique was first published 

Boon ME, Marani E. Adriolo PJM, Steffelaar JW, Bots GTAM, Kok LP 
(1988) Microwave irradiation of human brains: Production of 
microscopic slides within one day, J Clin Pathol 41: 590-593

Adult human brains can take weeks to be adequately fixed by 
conventional methods.

This work was done using a BioRad H2500 microwave, now produced by 
Energy Beam Sciences.

I have done similar work more recently using a Hacker/Milestone 
microwave, and I can attest to the simplicity and consistency of the 

With foetal brains, the times can, of course, be shortened, but the 
principles remain the same (stabilize, cut, soak, then microwave fix).

best regards,
Steven Slap

At 10:22 AM -0500 12/5/03, Geoff McAuliffe wrote:
>Hi Steve:
>How long are you fixing the brains? 48 hours is the minimum for 
>formalin, no matter what the concentration. One week is not too long.
>How big are the brains? Fetal mose brain is easier to fix by 
>immersion than a fetal horse brain. Size does matter.
>Are you sure your formalin is good?
>Steve Machin UK wrote:
>>Could anyone help us with a problem we have in processing very soft
>>fetal brains?
>>We currently fix in 20% formalin in buffer but the brains are so soft
>>after processing they stick to the wrapping paper.
>>Any ideas on how we can harden them after fixation?
>>Best Wishes
>>Steve Machin UK

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