[Histonet] Ripples in Arterial sections

[Monfils, Paul]

	This is common when cutting sections of artery.  Actually the section isn't contracting after being cut.  Rather, just the opposite.  Virtually all tissues undergo substantial shrinkage during dehydration. The cut sections then rehydrate when floated on the water bath, and expand to approximately the original size of the tissue sample. Some tissues rehydrate quickly, others more slowly, and as a result, sections of some organs which are composed of different kinds of tissue may not rehydrate at a uniform rate.  Muscle tends to rehydrate slowly, which is why arterial sections, either alone or within sections of various organs, develop these "waves".  The connective tissues, collagen, and other components around the muscle fibers expand rapidly on the water bath, pulling on the muscle tissue which is more resistant to expansion.  There are a few options that will help eliminate this artifact.  First - patience!  If your water bath is sufficiently warm, such "waves" in the tissue will usually flatten considerably if not completely, if you wait long enough. You may have to let the sections float a couple of minutes or more.  Second, if they don't flatten sufficiently after a couple of minutes, increase the temperature of your water bath, close to the melting point of the paraffin you are using. That will cause the sections to spread more quickly.  And/or, third, use a "slide warmer".  If you are not familiar with that piece of equipment, it's basically a low temperature hotplate (maximum temp usually about 80 degrees C), with a larger surface area than a standard hotplate.  You cut your sections, drain them briefly, then lay the slides flat on the slide warmer, while there is still some moisture between the section and the slide..  At 80 degrees the wax in the sections will melt immediately, and the tissue will quickly spread and adhere to the slide. Leave them a couple of minutes or more, until all the water has evaporated from the slide.  80 degrees may be too warm for more delicate tissues, which may overspread, but relatively tough tissues like artery will do well at that temperature.




> ----------
> From: 	histonet-bounces <@t> lists.utsouthwestern.edu on behalf of JR R
> Sent: 	Wednesday, July 18, 2007 6:55 PM
> To: 	histonet <@t> lists.utsouthwestern.edu
> Subject: 	[Histonet] Ripples in Arterial sections
> 
> 
>    I  am cutting 5 micron sections from formalin fixed, paraffin embedded
>    segments of rabbit abdominal aorta.
> 
>    I  float  my  ribbons  in  a  warm water bath then pick them up with a
>    Superfrost Plus slide.
> 
>    When  I  check  my  sections  uner the microscope, the sections have a
>    wavy,  or rippled appearance--It is not really "wrinkles, in the sense
>    of  the paraffin  folding  and  sticking  to  itself--it  is as if the
>    arterial  segment  is  contracting  after  being cut.  It looks like a
>    circular roadway that dips down then up, then down, then up...
> 
>    Has  anyone  ever  seen  this  artifact  with  arterial sections?  Any
>    ideas abiut why uit happens and what I could do to prevent it?
> 
>    Thanks
> 
> 
>    Jerry L. Ricks
> 
>    Research Scientist
> 
>    U.W. Medicine at South Lake Union
> 
>    815 Mercer Street
> 
>    Seattle, WA 98109
> 
>    (206)-685-7190
>      _________________________________________________________________
> 
>    [1]See what youre getting intobefore you go there 
> 
> References
> 
>    1. http://g.msn.com/8HMAENUS/2734??PS=47575
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