Do you mean throw away specimens or equipment?

> ----------
> From: 	Simon Smith[SMTP:ssmith@skeletech.com]
> Sent: 	Wednesday, April 26, 2000 11:15 AM
> To: 	Histonet (E-mail)
> Subject: 	RE: WHERE ARE THE CO2 MICROTOMES?
> 
> We had two of them when I worked at the London Hospital back in
> Blighty.  We
> found both of them in dumpsters when the anatomy department had a
> clear out.
> 
> 
> We used one of them once to cut serial 100um sections of unfixed human
> cartilage and subchondral bone.  To do this we clamped it to a shelf
> in the
> walk in -20 freezer, let the temperature equilibrate, then removed it
> when
> the thing siezed solid to replace the lubricant with low temperature
> lube.
> 
> Once set up it worked pretty well, you put on your skiing gear, go in,
> cut a
> few sections, come out, warm up, go back in.
> 
> I wonder where it is now?  I would guess either in the dumpster or
> where we
> left it surrounded by a group of puzzled biochemists wondering what
> the hell
> it is.
> 
> I have another semi off-topic question; do histologists ever throw
> anything
> away?  I have noticed this inability to part with anything in the
> majority
> of the histologists I respect.
> 
> Regards
> 
> Simon
> 
> Simon Smith B.Sc. AIBMS
> Supervisor, Laboratory Resources
> Skeletech, Inc.
> 22002 26th Ave SE, Suite 104
> Bothell   WA   98021
> Voice: (425) 424 2663   Fax:  (425) 424 2600
> E-mail: ssmith@skeletech.com  
> 
> -----Original Message-----
> From: J. A. Kiernan [mailto:jkiernan@julian.uwo.ca]
> Sent: Wednesday, April 26, 2000 7:37 AM
> To: Paulo Faria
> Cc: Histonet
> Subject: Re: WHERE ARE THE CO2 MICROTOMES?
> 
> 
> On Tue, 25 Apr 2000, Paulo Faria wrote:
> 
> > ... Where are the old CO2 microtomes?  I thought 
> > that before cryostats were readily available they were popular. Is
> that 
> > true? Where are they? 
> 
>  One of them, made by Leitz, is in my lab. It's at least 40 years old,
>  has served me well for the last 27, and is still in regular use. 
> 
>  Opinion: For getting thick sections of formaldehyde-fixed organs (and
>    I mean FIXED, at least overnight and preferably for a week), you
> can't
>    beat a CO2 freezer. Unless you're supremely skilful you can't get
>    serial sections; for this you need accessories that maintain the 
>    temperature of the chuck, either by circulating cold alcohol
> through
>    its innards or by using a Peltier-effect device (which needs
>    circulating tap water to carry the heat away from its "hot" 
>    thermocouple junctions).
> 
>    A pathologist examining a frozen section from this traditional
>    instrument must be able to evaluate sections very much thicker than
>    the 4 to 7 um of routine paraffin histology. The screw advance
>    on a typical CO2 freezer is calibrated from 0 to 100 um, and you 
>    can waggle the handle (moving the blade) to do double or treble
>    increments of thickness, but unless you can make use of occasional
>    lucky scraps don't expect anything thinner than about 20 um. A
>    freezing microtome is at its best with sections that are nominally
>    40 to 80 um thick. The real thickness is variable, as is obvious
>    at a glance to anyone who uses one. 
>  
>    Cryostats offer many advantages over the freezing microtome:
> thinner
>    sections; fixation is optional, etc etc.  There are nevertheless
>    plenty of circumstances when thicker sections are more informative
>    than thin ones. It isn't easy to cut an 80 um section of anything,
>    fixed or unfixed, in a cryostat. 
> 
>    Another good thing about freezing with carbon dioxide is that
>    it's fast, and ice crystal holes are rarely visible in the
>    sections.
> 
>  Perhaps some will disagree about these perceived virtues of the
>  CO2 freezing microtome!
> 
>  John A. Kiernan,
>  Department of Anatomy & Cell Biology,
>  The University of Western Ontario,
>  LONDON,  Canada  N6A 5C1
> 
> 
>