---------------------- Forwarded by Rande Kline/EMI/Merck on 01/26/2000
11:27 AM
---------------------------


Rande Kline
01/26/2000 11:18 AM

To:   "Jim Ball" <xryhisto@ovis.net>
cc:
Subject:  Re: first wax change  (Document link: Database 'Rande Kline', View
      '($Sent)')

Hi Jim,

I'm curious to why xylene is designated to be one of the culprits causing the
tissues to dry out.

I found if the 1st paraffin became too infiltrated with xylene the result was
poor inpregnation of paraffin into the tissue.  Therefore, tissues were on the
mussy side.  As a matter of fact, the weekend or holiday schedules for the
processors had the added hours in xylene not formalin to eleviate some of the
cross- linking caused by prolonged submersion in formalin.
Never experienced drying.

My suggestion would be to use a low-melting point paraffin.  It is alot gentler
on tissue especially biopsies.  It seems to me that paraffin baths are kept too
high which I believe is causing the majority of the problem.  Make sure the
rest
of the stations have ambient temperature.

I believe the problem is temperature related or alcohol related, maybe both.

Here's what we did in regards to the paraffin.  All paraffin baths were changed
on Monday's along with the rest of the solutions on the processors.  On
Wednesay's all solutions, including the paraffin where bumped.  The lab had
Shandon Hypercenters.

Another suggestion, check to make sure the xylene is draining completely out of
the processing tank before is allows the paraffin in.

Good luck.

Rande Kline, HT (ASCP)
Technical Services
EM Science/BDH




"Jim Ball" <xryhisto@ovis.net> on 01/24/2000 06:41:10 PM

To:   histonet@pathology.swmed.edu
cc:    (bcc: Rande Kline/EMI/Merck)
Subject:  first wax change



I have been a firm believer that dry tissue can be caused by to much xylene
in the first wax after the clearing process as much as over dehydration. I
have found that the least aount of time the tissue spends in this station
the better. I have tried to keep the over all exposure to 15 to 20 minutes.
Our department has gone with a cheaper variant of paraffin and the
brittleness of the tissue has increased considerable. My question is, How
often do you in histo cyber space change this wax. When we were getting a
good quality wax I was replacing half of this station with half the station
that followed in the process after about ever 350 to 400 blocks. This worked
out to be about every third day the waxes would be rotated even if we had
not reached 400 blocks there seemed to be enough carry over to justify this
rule of thumb.
          I have always thought that the fresher the wax the more insulating
properties it had as xylene was introduced, but eventually this insulating
property was lost and the 60 plus degrees helped this station to act as a
french frying unit, This effect was multipled if xylene was allowed to build
up in the next station and the next station. Would like to hear other
peoples view on this subject. Oh yea we are using the VIP processor so each
processor may allow for more or less blocks in my simple equation, and as
the old saying goes " Hit me with your best shot "