Re: [Histonet] Steve Slap Please Read

From:"Steven E. Slap"

Hi Dannie & HistoNetters

Happy 2004 to All

First, to address the side issue of finding histotechs on the 
Internet.  Please don't forget that many of us (myself included) can 
be e-mailed directly from "The Directory of Histotechs on the Web" at  If you are not yet listed, but want tobe, 
there is a submission form available, or you can just send your 
listing to me at

Now, forgive me a brief plea.  Peggy Wenk and I have maintained this 
web site, "The Histotech's Home Page", as a volunteer effort, for 
some years now.  Over the years, we have been aided by the generous 
financial support of several commercial sponsors, but  we are now 
down to one sponsor (thank you, Pacific Southwest Lab Supplies!!!), 
and this is not nearly enough to pay the bills associated with 
maintaining the site.  As I am now self-employed, I cannot afford to 
support the site on my own.  I hope that several companies can step 
forward in 2004 to help out and keep this valuable resource available.

Now to Dannie's question.

The purpose of the vacuum step in microwave histoprocessing is to 
remove all residual isopropanol from the tissue.  The problem with 
the placentas, I think, is twofold.  First, there may still be 
residual water in the tissue (try extending the isopropanol step). 
Second, there is a very large amount of alcohol being carried over 
within the tissue into the vacuum step into the paraffin.  As the 
isopropanol flash evaporates, it is causing a "volcano" effect in the 
paraffin, and paraffin is splattering up into the vacuum.  Both of 
these problems appear only with very large tissues, and would not be 
seen with biopsies.  In addition to extending the isopropanol step, I 
would make sure that the paraffin is at the correct temperature at 
the start of the cycle, and is not overfilled as first steps to 
resolving the problem.

Dannie-  thanks for the compliment, and feel free to contact me directly.

best regards,
Steven Slap
Microwave Consultant

At 4:00 PM -0500 1/1/04, wrote:
>Hello, Steve:
>No matter what, you are still the microwave specialist and I need your input,
>if you would be so gracious as to reply.
>Our Milestone Renaissance is being used daily for a run of placenta blocks.
>(I know bloody specimens are not highly recommended for microwave.) 
>Do you have
>any idea why paraffin is being sucked into the vacuum tube?  This is
>happening at various times....not necessarily when it has a full 
>load. Our first run
>of biopsies is fine.  The placentas are on the second run.  The paraffin is up
>to temp @ 80 C.  We were wondering if the problem is simply because they ARE
>bloody tissue and we just need to change the paraffin if we wish to use the
>microwave for this application.  What do you think?  I sure would 
>appreciate your
>expert knowledge on this.
>NOTE:  Anyone else who has any ideas (Tim Morken, during your CDC days?) ....
>  you are most welcome to jump in.
>Steve, I hope you had a good holiday.  Happy 2004!!!!
>Same to all you people around the world who read and learn from HistoNet.
>Dannie Blake, HT (ASCP)
>Sierra Pathology, Fresno Community Hospital
>Fresno, California
>Histonet mailing list

Histonet mailing list

<< Previous Message | Next Message >>