[Histonet] How to get good cross sections of the mouse small intestine

Gayle Callis gcallis <@t> montana.edu
Tue Jan 24 09:50:35 CST 2006


Excellent suggestion - for pinning down the samples, I suggest using 
disposable hypodermic needles - the latter do NOT rust or corrode in 
aqueous based NBF - needles are stainless steel.  Tiny needles (24 or less 
gauge)  for this purpose and not tear the ends of the intestine to bits 
with larger gauge.

The Gordian knot description was so true and our loops of intestine always 
were filled with mouse feces!!!  Once fixed, couldn't removed - microtomy 
was no fun and sections looked terrible.

You can also use cork strips (purchased from hardware store, very cheap) 
then toss them out later.  We would stand these on end in a deep bucket 
with lid - tagged carefully.  And a cheap pan with a lid is the cake pan 
sizes or larger, with lids - Rubbermaid or some other plastic.  Very nice 
to reach into a pan and get the samples - loved this idea.

  At 04:44 PM 1/23/2006, you wrote:
>         In addition to Gayle's suggestions, you might want to physically
>hold the intestine straight while the formalin fixes and hardens it.  After
>injecting formalin as Gayle said, I pin one end of it in a wax-lined
>dissection pan, then stretch it gently, just enough to straighten it, and
>pin the other end to keep it straight, then cover it with formalin. People
>sometimes send me intestine specimens which they have simply removed from
>the animal and dropped into formalin, resulting in a hardened gordian knot,
>all parts of which are curved to some degree, so that pieces cut from the
>intestine are shaped like parentheses.  It's difficult to get a good
>perpendicular section of a curved object.  If you don't have a dissecting
>pan you can easily make one; or you can just pin the specimen onto a strip
>of heavy corrugated cardbord or soft wood and drop it specimen side down
>into a dish of formalin.
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Gayle Callis HTL, HT, MT(ASCP)
Research Histopathology Supervisor
Veterinary Molecular Biology
Montana State University
Bozeman MT 59717

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