Re: [Histonet] Cryostat decontamination

Thanks Jan for the interesting message on disinfection.

I have usually used Formalin in the past on all the old cryostats but I
remember buying a solution from Leica called "cryofect" which (I think) is
chlorhexidine in 70% isopropanol. Is it still marketed by Leica? as I
remember it was to be used without defrosting the cryostat.

Kevin Gibbon
QLT Inc.

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|         |           09/26/2005 03:14 PM             |
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  |       Subject:  [Histonet] Cryostat decontamination                                                                          |

Hi Dorothy and Histonet subscribers,

I'm writing in response to comments I've seen in the past few days about UV
disinfection procedures for cryostats.  I'm not sure if the listing on the
spreadsheet from Gloria's workshop referred to our instrument or not, but
Leica recently released the CM1850 UV cryostat with ultraviolet light (UVC) I thought I should chime in.

We had the same questions about cryostat disinfection that many of you have
had.  Therefore, as part of our development process we hired an independent
laboratory to perform tests that would verify the efficacy of UVC exposure
against specific pathogens in the CM1850 at cold temperatures.  The results
assured us that our system is a convenient and safe means of inactivating
microorganisms in the air and on exposed surfaces at temperatures down to
-20C and that using the system significantly reduces the risk of infection
to the operator.  We proudly provide a CD that contains the certificate
from the consultant, details of how the tests were performed and the
results that were obtained.

Whether a cryostat has a built-in disinfection system of any kind or not,
there are several very important things to remember about disinfecting
      1.  Before beginning a disinfection protocol, don personal protective
equipment (puncture and penetration resistant gloves, gowns, etc).

      2.  Remove all debris from the cryostat and disposed of it according
to the policies and procedures of your institution. The debris must be
removed because organic material (blood and proteins) may contain high
concentrations of microorganisms and could possibly inactivate chemical
germicides or prevent access to contaminated surfaces.

      3.  Use 70% ethyl alcohol to clean the cryostat.  The germicidal
activity of ethyl alcohol is most effective in that range and it has an
advantage over isopropyl alcohol of being able to kill hydrophilic viruses.

      4.  For those of us in the USA (other countries have access to other
products), the EPA maintains a list of Antimicrobial Chemical/Registration
Number Indexes and it is posted on their website From this link you can find
agents effective against bloodborne pathogens such as Mycobacterium
tuberculosis, human HIV-1 virus, Hepatitis B or Hepatitis C virus.  It is
critical to remember that NONE of these solutions have been tested at low
temperatures and they can only be used at room temperature.

      5.  Do not create aerosols by spraying disinfectant (or anything
else) in an open cryostat chamber.  Pour disinfectants onto absorbent
disposable towels and allow them to remain in contact with contaminated
surfaces for the length of time specified in the instructions of the
individual agents.

I hope this information is useful.  Please let me know if you have any

Best wishes to all,

Jan Minshew HT, HTL(ASCP)
Marketing Manager
Leica Microsystems, Inc.
2345 Waukegan Rd
Bannockburn, IL 60015
800.248.0123 x7051


                      Sent by:                              To:
                      histonet-bounces@lists.utsouth        cc:       (bcc:
Jan Minshew/USDER/West/Leica)
                                       Subject:  Re:
[Histonet] cryostat decontamination

                      09/26/2005 09:59 AM

I recently attended Gloria Limetti's seminar at NSH about cryostat and
microtome features.  She is from the University of Pitssburgh.   Attendees
given an extensive spreadsheet listing which features were  available on
models.  In an effort not to come across as  non vendor specific, Gloria
assigned all the companies letters.  Just  looking over the features, it's
easy to decipher which company is  which.  I don't have my copy in front of
now but I believe there are 7  models with various types of decontamination

systems offered.
Hacker Instruments SL5000 is one of the units that is available with an
automatic decontamination feature, perhaps Gloria will post the names of
other companies.
As for UV decontamination, it is my understanding the the UV light is only

effective on the surfaces of the cryostat and microtome chamber where the
 actually comes into contact.  Nooks and cranies would still need to be
wiped down manually.  As with Vinnie, I would be interested in reading  a
study or
two on it's effectiveness in histology applications.

Dorothy Murphy Traczyk
National  Sales Manager
Hacker Instruments & Industries Inc.
PO Box  1176
Winnsboro, SC 29180
_www.hacker_ (http://www.hacker/)
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