RE: araldite

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From:"BrosnanWatters, Gayle" <>
To:'Roger Moretz' <>, 'histonet' <>
Content-Type:text/plain; charset="windows-1252"

	Wow, I might have to actually learn something new!  A heat pen, huh?
Does it work on relatively "thick" sections such as 1 micron sections, and
on huge ones like a whole mouse brain (I have a specially machined chuck
that fits into an MT2 so I can cut a whole one)?  Nothing makes me madder
than to have exactly the section I need, and then, in spite of having done
it thousands of times, losing that section because I overheated the water on
the hot plate!  This pen would prevent that?
	 And while I'm at it, I have always been afraid of diamond knives
because they told me they don't last and that they cost so much I probably
couldn't keep myself in them - what's this about a "thick section" diamond
knife?  Where would I get details on that?
	This is so cool;  I can ask questions of really knowledgable people
without feeling too much like an idiot!!
	The psychologist

> ----------
> From: 	Roger Moretz
> Sent: 	Friday, February 18, 2000 8:40 PM
> To:;
> Subject: 	Re: araldite
> I am rather surprised to see the old toluene (or
> carbon tet, or xylene--you name it, it's been done)
> technique still being used.  And I used it for years
> and years....what was I saying???  Oh yes.  Can't
> remember what causes those memory lapses....
> Anyway, seriously.  Several of the EM supply houses
> sell a little "Heat Pen" unit that does a fantastic
> job of flattening sections on the water in the knife
> boat.  I switched to one of those over 15 years ago,
> and at least exposure to solvent fumes at the
> ultramicrotome no longer contribute to neuronal
> necrosis!!!  I don't mean to slight anyone, (I'm at
> home and don't have the catalogs at hand), but I do
> know that Ted Pella carries the heat pen.  
> As to knife angle, etc.  The usual 6 degrees should
> work, and glass knives should last if treated kindly. 
> However, if you can afford it, the "thick section"
> diamond knife will speed things up a lot.  
> Finally, heating the slide/water/section is critical,
> but can be frustrating if you haven't done it before. 
> I use a similar technique to those mentioned already,
> but preheat the slide and drop of water briefly prior
> to placing the section on the water surface.  You will
> have to practice to figure out the best heating time,
> temperature and drain/drying protocol for your tissue
> and the size of the section.  I have done this for
> block sizes that were nearly the whole embedding
> capsule diameter (coronal sections of half a mouse
> brain).  
> Hope all of our responses will help.
> Roger Moretz, Ph.D.
> Dept. of Toxicology
> Boehringer Ingelheim Pharmaceuticals
> --- wrote:
> > In addition to the heating all ready mentioned, you
> > can also use an 
> > applicator stick that the tip has been dipped/soaked
> > in toluene and wave it 
> > closely over/above the section ....either while its
> > in your boat or still 
> > floating on water on the hot plate...this spreads
> > the section even more. 
> > Don't touch the water or the section....
> > 
> > Elizabeth
> > 
> > 
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