RE: [Histonet] magnetized tissue??

From:"Monfils, Paul"

Thanks for the various suggestions, but it is apparent that others have not
seen this happening, which rather surprises me as I have seen it pretty
regularly for years.  What I described is definitely not due to any sort of
fluid dynamics or the shape or density of the tissue sample. That might
cause the tissue to float to the bottom of the mold a certain way.  But what
I am seeing is quite different.  The tissue, once it is released into the
liquid wax, and regardless of how it is oriented when released, instantly
whips around to orient itself cut end down, and sticks fast to the bottom of
the mold. I mean instantly, like a tenth of a second or less. If I pick it
up with forceps and release it, it instantly reorients itself the same way.
I agree with the one poster who suggested it must be some sort of static
process, but I still can't understand how or why it happens. Anyway, it is
not really a problem, just a matter of curiosity, and thanks again to all
who responded.

> ----------
> From: 	Rene J Buesa
> Sent: 	Friday, July 14, 2006 9:01 AM
> To: 	Monfils, Paul
> Subject: 	Re: [Histonet] magnetized tissue??
> Paul:
> No, it never happened to me.
> Consider the following explanation:
> the cut end by the effect of being cut is squezed/compressed a little
> making it slightly narrower/flatter than the non cut end.
> When you place it back into the melted paraffin, by mere dynamics the
> slightly flattened end will be less boyant than the other end, and will
> sink faster.
> Just a thought!
> René J.
> "Monfils, Paul"  wrote:
> 	I have noticed an odd phenomenon many times, so I assume others must
> have
> 	noticed it too? I often have slender, cylindrical specimens like
> vessels or
> 	mouse spinal cord that have to be cut in cross section and therefore
> have to
> 	be embedded "on end". Sometimes a specimen is a little too long to
> mount on
> 	end without the cassette resting on top of the specimen. In such
> cases I
> 	take a scalpel blade and trim a bit off the length, to make the
> specimen
> 	"shorter". When I take a specimen that has been trimmed in this way,
> and
> 	drop it back into the stainless steel embedding mold filled with
> paraffin,
> 	the specimen instantly flips around and attaches on end to the
> bottom of the
> 	mold, always by the freshly cut end, just as though it somehow
> became
> 	"magnetized" by my trimming it. Has anyone else observed this?
> (Please say
> 	yes, I can't be the only one!) If so, does anyone have any idea
> how/why
> 	this occurs? Obviously it is not true magnetism operating here
> because (1)
> 	tissue does not become magnetized, and (2) stainless steel is not
> attracted
> 	to a magnet.
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