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David Pickles
12-07-1994, 01:23 AM
I recently posted the following query to the list:


"Our Department is currently re-evaluating and updating local safety
procedures for the handling of unfixed human tissue (normally cadaveric)
used in biomechanical experiments. Clearly such tests are somewhat
different to other areas of work using human tissue in that they are
usually highly invasive, and often involve the application of high loads
to large specimens, frequently to failure. A different set of rules is
needed than is required, say, for handling human cells in a test-tube.

It would be very useful to hear what procedures other labs are currently
adopting - is there a common consensus of safety rules? What about
screening of cadaveric material for HIV, Hep B/C etc - is this a
requirement? How about the problem of using expensive equipment (eg
materials testing machines) which also need to be used by other workers
but not involving human tissue? What procedures for sterilization/
disinfection of non-disposable equipment are used?"


There follows a summary of all the responses I received - thanks to all
who replied. Specific safety requirements etc seem to vary quite widely
between institutions: the answer to one of my questions being that there
is no common consensus, particularly, for example, as to whether screening
of tissue is required or whether personnel should be immunized against Hep
B etc.

I hope that this will stimulate some discussion on the subject.


David Pickles Comparative Orthopaedic Research Unit
Department of Anatomy
University of Bristol
Southwell Street
Bristol
BS2 8EJ
United Kingdom



==================== SUMMARY OF RESPONSES RECEIVED: ========================

To kick off , the following is a summary of the protocol currently in
force in our lab:

o All tissue used must have been screened for HIV and hepatitis
B. Specimens are stored in a dedicated freezer.

o All personnel working with human tissue are immunised against
tetanus, TB, polio and hepatitis B. Eye protection; lab-coats
(colour-coded for use with human tissue only); disposable
overall, mask, gloves and overshoes to be worn at all times,
plus Kevlar lining gloves during dissection.

o Dissection and mounting are carried out within a downflow
cabinet in a purpose-built human tissue room, which has
strictly limited access, is kept locked, is under negative
pressure, and is sealable for emergency formalin bombing.

o Waste tissue and badly contaminated disposables are stored in
the human tissue freezer and subsequently incinerated on-
site.

o During testing, specimens are shrouded to prevent dispersion
of debris. Test machine and other non-disposable kit are
thoroughly cleaned with chlorine-based virucidal disinfectant
after use.

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From: "M.H. SHEREBRIN"

We use only tissue that has been screened and does not carry communicable
diseases. All persons working with human tissues must be immunized. In
some cases masks and protective gloves are worn even after above
precautions. I suppose there is still a small chance that a virus will
not be detected even though present.

It is a very important question that you pose and many on the net would
be interested in reading the replies you get.

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From: dean@lucifer.MEDS.CWRU.Edu (David Dean Ph.D.)

Why not confer with the local faculty in charge of the gross anatomy lab.
Here we cooperate with a number of clinical departments. They assist in
the lab and they often harvest pieces of anatomy (after the students
finish) for uses in their lab. As far as I know, and I claim no authority,
the standard phenol/formaldehyde preparation leaves virtually no risk of
Hepatitis and AIDS infection. The people at risk are the embalmers.

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From: A Hayes

Several years ago now we had exactly these problems when setting up some
biomaterials testing facilities at the University of Bath. Initially I was
testing human cadaveric material, but subsequently equine cadaveric
material. Again, because we were operating within an ordinary Materials
Science department, and due to recent changes in the law with regards to
the responsibility of individuals towards the health and safety of
themselves and other people using the same laboratory or equipment, I
researched this problem in some detail.

The publications that the Safety Office at the University of Bath
recommended to me, were in fact very useful. These were:

"Safe working and the prevention of infection in clinical laboratories"
published by the Health and Safety Executive. ISBN 0-11-885446-1

and

"Safe working and the prevention of infection in clinical laboratories -
model rules for staff and visitors" published by the Health & Safety
Executive. ISBN 0-11-885442-9.

Both publications were available from Dillons Ltd., 116 New Street,
Birmingham, B2 4JJ.

I also referred to the "Code of Practice for the Prevention of Infection
in Clinical Laboratories and Post-Mortem Rooms" published by the Dept. of
Health and Social Security. ISBN 0-11-320464-7.

As far as I can remember the guidelines for the testing of human cadaveric
material were very different from those for testing animal tissue. The
human tissue I was testing was unscreened, but I took the personal
precaution of being vaccinated against Hepatitis B. However, this full
course of treatment takes 6 months to become fully effective. When
testing the equine material I also made sure that my tetanus jabs were
up-to-date.

When we initially started this work our safety precautions were lapse to
say the least. It wasn't until later when I had actually finished working
with the human material that our protocol became much tighter.To give you
some idea of the precautions that I took when working with fresh equine
cadaveric material read the following! (In fact I was also working with a
girl at the same time who was analysing human synovial fluids, and so we
tended to have the same routines.)

With regards to sterilisation of equipment: After any work we washed all
surfaces with a dilute solution of chlorine (I think 2% is the recommended
concentration). All dissecting equipment was soaked in chlorine solution
with a detergent that was specially acquired that wouldn't react with the
chlorine to reduce its effectiveness, and all drilling and testing
equipment was wiped with a 70% alcohol solution. As you may have gathered
by now it was a bit of a palava! All the testing was done whilst being
kitted up with lab coat, chain mail glove on the non-cutting hand,
disposable gloves, and a theatre mask to reduce the possibiliy of
infection via any aerosols generated whilst cutting the material.

On reflection some of this was probably unnecessary. However, it will give
you some idea of the complexity of the situation if you follow the codes
of practice to the letter.


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From: grimm@ssb.eng.wayne.edu (Michelle Grimm)

I have worked with cadaveric tissue at two locations. At the University
of Pennsylvania, we did not receive any screening information when we
received the material. Only known HIV+ individuals were excluded from
cadavers accepted by the school. We followed universal precautions with
all specimens (gloves, face shields when necessary, lab coats) and cleaned
up all areas thoroughly with 10% bleach solution. This included areas
used by others not working with cadaveric material. One of the necessities
is to make sure that people are aware of what you are working with when
they walk into a lab.

At Wayne State University, all subjects are tested for HIV and HBV before
being accepted as cadavers. Full disposable cover suits are worn, as
impact testing is done which can create a greater mess. Again, areas are
used for both cadaveric and non-cadaveric testing and so decontamination
is important.


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From: "G.J. KLEINRENSINK @ ANAT"

You are right. This is an important issue. Although I read your orignal
message, I did not respond because I had no real answer to your questions.
Perhaps this message will neverthess be of any help. At least you will
have three reactions on a subject in which I'm very interested and should
be of interset to a lot more than three people in the "world that is
called INTERNET". We at the anatomy department of the Erasmus University
Rotterdam (EUR) are involved in functional anatomical/biomechanical
research, but mostly are working with fixed (embalmed) material. The
people of the dissection room who actually are confronted with
unembalmed("fresh") bodies are vaccinated against Hepatitis B and that's
all. Perhaps you are interested in a comparison between results on
embalmed vs. unembalmed human specimens.

Recently I performed a study on mechanical tension in peripheral nerves
due to normal range of motion movements of the arm. We placed "buckle"
force transducers on the Median,Ulnar Radial nerve and the Brachial
plexus. The measurements were performed on embalmed and (only two)
unembalmed human bodies. The results on the median nerve of embalmed
bodies will be published in "the first possible" issue of Clinical
Biomechanics. However, one of the comments of the reviewers we received
was: "what about unembalmed specimens".

We answered by sending a new manuscript in which we compared the results
of unembalmed and embalmed bodies. This manuscript was also accepted and
will also be placed in the same "first possible issue". The manuscript on
brachial plexus tension will be submitted in December. Because it's
supposed relevance for neurologists it will be submitted to a neurological
journal. If you are interested I will send it to you when it is published.

In our faculty the experiments on "fresh" or "fresh frozen" specimens are
not performed at the department of Anatomy but at the dept. of Pathologic
(forensic?) Anatomy. We have no facilities to work with unembalmed bodies.
We cannot dispose of blood or other unembalmed biological material and the
assistants of the dissection room are not qualified and not willing to do
so. They are legally protected in their point of view.


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From: "Thomas G. Loebig"

I've a contribution to your discussion, just been really busy lately. No
screening done here, just careful about handling...use gloves and scrubs
always, masks and goggles when appropriate. We don't share our equipment
with anyone else, but we try to enforce strict protection and cleaning
rules. Cover expensive equipment like load cells, electronics if possible.
Clean all equipment with antibacterial soap and a mild bleach solution.
Liberally spray with water displacer (WD-40) and keep the machines well
oiled. We've all been vaccinated against Hepatitis also.

[...and in a follow-up message...]

I just dug out a paper by John M. Cavanaugh and Albert I. King form Wayne
State University, Detroit, Michigan entitled "Control of Tansmission of
HIV and Other Bloodborne Pathogens in Biomechanical Cadaveric Testing."
JOR, 1990, 8:2;159-166. They present infection control guidelines issued
by the US Centers for Disease Control. In summary: protective measures
include use of gloves, masks, eyewear, gowns and waterproof aprons. Also,
instruments and surfaces should be decontaminated with an appropriate
chemical germicide. They also recommend screening for HIV and HBV.


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From: msacks@coeds.eng.miami.edu (Dr. Michael S. Sacks)

Let me first introduce myself. My name is Michael Sacks and I am an
assistant professor of biomedical eng. at U. Miami (FL). My area of
research is soft-tissue mechanics. One of the several projects I am
currently working on is the biomechanics of human Dura Mater, which we get
from the U.M. tissue bank. We are current developing more sophisticated
techniques to evaluate the effects of different sterilization treatments
and varying degrees of rehydration. Our tissue bank handles all the
"messy" biological testing. However, we do have a concern in handling
tissues that, although have passed all screening, are still human tissue
and may have residual amounts of viral or bacterial material. I am
interested in what you find and would be happy to find out exactly how our
tissue bank does its work.


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From: egmjp@cc.flinders.edu.au (Mark Pearcy)

The protocols we use in our lab are quite strict. All fresh human
material is tested as though infected. The pathology procedures before we
get the material are supposed to screen out known infected material but
you can never be sure.

This being the case, we have a dedicated lab for our biological materials
testing. The machine is difficult to steralise so although we keep it
clean and wash appropriate parts with alcohol the machine is treated as
infected material too. Herein lies a problem in that I would not accept a
machine being used for ordinary mechanical testing by other groups not
versed in biological safety procedures using the same machine.

If the machine is used for standard testing of other materials then the
conditions of use should be exactly the same as though they were testing
fresh human material. We have an Engineer responsible for the lab and
running of tests on our machine and he would supervise any testing.

Certainly you should also have guards round any materials likely to fail
explosively and the operators should then also wear protective glasses or
goggles. The operators should also be vaccinated against Hep B and
anything else that becomes available.

This is probably not what you wanted to hear but this is the Best Practice
as far as I am aware.


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From: ath@bihobl2.bih.harvard.edu (Aaron T. Hecker)

We have been in the business of handling and testing cadaveric material
for the past 15 years. Several years ago I developed the attached protocol
for handling cadaveric material as a guide for people working in our lab.
Although it is specific for our lab, I hope it will be of some help. None
of our material is screened for common infectious diseases so we treat
all material as infected. If you have any questions please feel free to
correspond to this email address. Good luck.

[...attached protocol deleted since it is in Postscript language and as
such very long and not readable directly - it's very useful though and as
Dr Hecker said I could include it in this summary, I'll email it to anyone
who wants a copy.]

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From: diop@ensam-paris.fr (Amadou DIOP)

At the ENSAM biomechanical Laboratory, we used to sterilize our fresh
anatomical samples by Beta-Irradiation (2.5 Mrad) as it is done for
implantable allografts or implants. We don't know if this procedure is
fully efficient for HIV or Hep B/C, but we believe it dramatically
decrease the risks. Do someone have precise informations about that? I
will also be interested to have discussions about the mechanical effects
of this procedure. Its influence seems to be limited on cortical bone,
but what about cancellous bone and soft tissues?

This procedure, of course, don't exempt us from the use of overalls, gloves,
glasses during drillings...


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From: SANIF KAMIN

There is is article " Control of Transmission of HIV and Other Bloodborne Patho
gens in Biomechanical Cadaveric Testing" by J M Cavanaugh and A I King publishe
d in Journal of Orthopaedic Research 1990, p 159-166. It have some interesting
guidelines on cadaveric work.

In our lab, the normal procedure after cadaveric testing is :-
a) Clean and autoclave all surgical equipment used.
b) Clean all equipment with disinfectant ( including the Universal Testing
Machine, Shidmadzu DCS 5000)
c) Switch on Ultra Violet lights for half hour. (our lab is fitted with UV
lights on all sides).

We also use a different set of lab coats for cadaveric work.


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