Hi Gayle et al.,
When it finally got through to me that the paraffin I was using had DMSO
I quit using it.  A few years ago when DMSO was being used for joint pain
I think it was Seattle Univ. that did a study on rats.  The DMSO rats were
shown to have lesions that look just like MS.  I did not follow up on
that so maybe there is better info on it now.  I just have not heard of
it.
Trisha
 On Mon, 7 Jun 1999, Gayle Callis wrote:

> DMSO, dimethyl sulfoxide, a very volatile solvent (can't you taste it when
> you open up a 60C oven?) is the culprit.  The DMSO is supposed to make
> penetration easier (used for horses topically to reduce pain and inflammation
> of joints) and probably works well with the paraffin as well.  BUT is 
> does contribute to the rusting of metal, and ruination of solenoids of 
> incubators, and other instruments other than just automated processors.  I
> was more worried about my constant exposure to the DMSO and long term
> effects, enough to work with something else along with watching some of the
> metal parts of things turn rusty brown.  
> 
> There are other paraffins which are nice for infiltration.  Surgipath has
> an infiltration media which contains little or no plastic polymers, is
> used solely for infiltration purposes, works very well and for large bone
> slabs, in our case the proximal and distal ends of tibias or femurs from
> sheep, goats, and dogs.  We merely increased the time of infiltration on
> the VIP to 4 hours per change (4 changes!) for these huge dense pieces of bone 
> and embedded in Surgipath embedding media which contains
> the polymers needed for good sectioning.  Worked very well.  Just don't
> try to use the infiltration media for embedding, disaster, cutting poorly set
> putty is a good comparison for that mistake.
> 
> The TIME of infiltration on dense tissues may be a big factor, and 
> alternating vacuum and pressure, as most automated processors now have,
> is very important.  I preferred to infiltrate whole rat knees, from mature
> rats, for 2 hours per station, 4 changes.  In fact, all changes from 70% 
> ethanol through clearing and paraffins were done at 2 hours per station,
> and could cut at 3 micrometers, disposable blades, with excellent 
> staining results.
> 
> Gayle Callis 
> 
> 

Trisha