Regarding cryostat sectioning of brain...I think the liquid N2/isopentane
is too cold that is, it freezes the tisue too rapidly, the outside freezes
before the inside, leading to cracks.  I have frozen non-human primate
brain in oct on dry ice with good results.  If the tissue has been fixed,
we cryoprotect in 20-30% sucrose before freezing.  Sections would be cut
on a steel knife with cryostat temperature -12 to -16 C I also use an
antiroll plate and pick sections up on subbed slides chiled to cryostat
temperature.
	I have a Hacker-Bright cryostat, in use    since 1987, used by a
mixed group,
with no problems.  The only thing I have replaced is one of the
temperature modules.

On Fri, 15 Oct 1999, Atoska Gentry wrote:

> Hello histo world; I'm in need of urgent help in a couple areas. First and
> foremost any veteran cryostat operators who are absolutely in love with
> their cryostats?  If you're out there I need to hear from you.  As we may
> be in the market for a new cryostat that has all of the bugs worked out if
> you know what I mean?  We have a 9 year old IEC Minotome Model 2488 which
> has for the past 2 years had to have repeat major repairs and is now in the
> shop awaiting redesigning of a part we just had replaced December of last
> year.  Also I am in need of pointers for obtaining good frozen sections on
> brain at 8u.  Right now we are doing mouse brains but we have several cat
> brains stored frozen for future use.  I quick freeze in isopentane cooled
> by liquid nitrogen.  I have been doing frozen sections for a little over a
> year but the majority of my work has been on dog muscle samples.  Which to
> my knowledge have netted satisfactory results.  However, the brain samples
> I did this week appear to have severe artifact ie. cracks, ice crystals?
> and etc.  Any help would be greatly appreciated.
>  My next problem is I need a thermostat for our old Tissue TekII vaccum
> infiltrator. Or better yet does anyone know of some form of a paraffin
> reservoir which is capable of accomodating a 1L paraffin picture?  My main
> line of work involves formalin fixed samples of varying sizes for which I
> use the archaic L shapes to form embedding molds.  If there's anyone else
> out there please contact me in regards to your method of keeping your
> sections in warm paraffin immersion until embedding of multiple sections
> are embedded.  i have been doing this for a number of years with the aid of
> the vaccum infiltrator serving as my reservior but now that it's broken it
> makes embedding a PAIN!  Thanks, Atoska
> 
> Atoska S. Gentry B.S., HT(ASCP)
> Research Assistant
> Scott-Rtichey Research Center
> College of Veterinary Medicine
> Auburn University, AL  36849
> PH (334) 844-5579
> FAX (334) 844-5850
> 
> 
> 
> 
>