BBC NEWS
Sterilisation 'may not kill CJD'

A survey has found that surgical instruments still have the potential
to harbour CJD even after sterilisation.

Edinburgh University found every instrument they tested was
contaminated with enough protein residue to pose a potential infection
risk.

The researchers tested instruments taken at random from five NHS
hospital trust sterile service departments.

The study, financed by the Department of Health, appears in the Journal
of Hospital Infection.

CJD, a degenerative and fatal brain disease, is thought to be caused by
mutated proteins called prions.

These twisted proteins are known to be able to cling to the surface of
surgical instruments, and are remarkably difficult to remove by
standard decontamination processes, which involve the use of detergents
and super-heating.

There have been instances of patients contracting CJD from contaminated
instruments during surgery.

The Edinburgh team found an average level of protein contamination of
0.2 microgrammes per square millimetre of instrument.

Unknown risk

If prions were found on so-called sterile instruments in the levels
recorded in the study, that would be billions of times the dose needed
to cause infection in humans.

The highest doses were found on instruments used to remove tonsils -
one of the tissues known to harbour prions.

Lead researcher Professor Bob Baxter, from the University's chemistry
department, said "You can never get something 100% clean, but we were
surprised at how much protein there was."

Professor Baxter said measures to quarantine surgical instruments were
taken if a patient was known to be at high risk of carrying CJD.

But he said that as a result of the use of contaminated blood supplies,
an unknown number of people could be harbouring the disease.

"There are certainly people out there who are at risk, but we don't
necessarily know who they are," he said.

The Edinburgh team has developed a more effective way to sterilise
instruments, using a technique called gas plasma sterilisation.

This uses radio waves to excite the molecules of harmless gases,
creating charged atoms called ions and radicals which effectively scour
the surface of the instruments, breaking down traces of biological
tissue and converting them to non-toxic gases.

Gas plasma sterilisation can remove prions to levels a thousand times
lower than those achieved by existing methods.

Professor Baxter has recommended the widespread introduction of gas
plasma cleaning to the Department of Health.

A Department of Health spokesperson said the study would be considered
by an expert group.

"Although we consider the gas plasma decontamination technique
interesting, it is not currently in a form that can be used in routine
decontamination of surgical instruments."

--------

CJD

- CJD is the commonest form of human prion disease
- There are different types, including sporadic CJD and variant CJD,
which is linked to BSE
- All forms of CJD are progressive neurological disorders which are
fatal and for which there is no cure
- In the UK, there are between 50 and 65 deaths each year from sporadic
CJD
- So far, there have been more than 150 deaths from variant CJD
- A study of appendix and tonsil samples suggests there could be around
12,000 people in Britain who carry vCJD
- The pre-symptomatic gestation period for CJD can be from a few years
to decades

--------------------------------------------
http://news.bbc.co.uk/go/pr/fr/-/2/h...th/5281100.stm

On 24 Aug 2006 09:16:13 -0700, wrote:

>BBC NEWS
>Sterilisation 'may not kill CJD'
>
>A survey has found that surgical instruments still have the potential
>to harbour CJD even after sterilisation.
>
>Edinburgh University found every instrument they tested was
>contaminated with enough protein residue to pose a potential infection
>risk.
>

[snip]

>
>These twisted proteins are known to be able to cling to the surface of
>surgical instruments, and are remarkably difficult to remove by
>standard decontamination processes, which involve the use of detergents
>and super-heating.
>
>There have been instances of patients contracting CJD from contaminated
>instruments during surgery.
>

[snip]

>The Edinburgh team has developed a more effective way to sterilise
>instruments, using a technique called gas plasma sterilisation.
>
>This uses radio waves to excite the molecules of harmless gases,
>creating charged atoms called ions and radicals which effectively scour
>the surface of the instruments, breaking down traces of biological
>tissue and converting them to non-toxic gases.
>
>Gas plasma sterilisation can remove prions to levels a thousand times
>lower than those achieved by existing methods.
>
>Professor Baxter has recommended the widespread introduction of gas
>plasma cleaning to the Department of Health.
>
>A Department of Health spokesperson said the study would be considered
>by an expert group.
>
>"Although we consider the gas plasma decontamination technique
>interesting, it is not currently in a form that can be used in routine
>decontamination of surgical instruments."
>

Gas plasma decontamination would undoubtedly be effective. It will also call
for lots of copies of high-tech equipment, and thus be a boon to
manufacturers. Designing and building that equipment will take time -- and of
course there has to be a study beforehand.

I suggest a cheap, simple interim solution: hydrogen peroxide. Even diluted
to 3% - 20%, as normally available to hospitals, it would probably be
effective. More concentrated forms will certainly destroy any trace organic
material they contact, while not harming the stainless steel instruments.

High-strength (80-95%) peroxide is non-toxic. It poses a moderate risk of
burns, but this can be avoided by promptly rinsing the exposed skin with
water.

In message >, Christopher P.
Winter wrote:

> I suggest a cheap, simple interim solution: hydrogen peroxide. Even
> diluted to 3% - 20%, as normally available to hospitals, it would probably
> be effective. More concentrated forms will certainly destroy any trace
> organic material they contact, while not harming the stainless steel
> instruments.

Two problems:

1) DHS is suddely twitchy about H2O2.
2) Actually, the stuff *does* affect stainless. Not rapidly in
moderate concentrations, but it does. Ask anyone who's used
the stuff for propellants (e.g an aunt of mine who worked on
NASA projects.)

--
begin signature.exe
A:*Because*it*messes*up*the*order*in*which*people* normally*read*text.
Q:*Why*is*top-posting*such*a*bad*thing?
A:*Top-posting.
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Happened in Denver hospital ten years ago and six other patients
were infected. US surgeons are supposed to use new equipment,
or super-sterlization techniques now.

wrote:
> BBC NEWS
> Sterilisation 'may not kill CJD'
>
> A survey has found that surgical instruments still have the potential
> to harbour CJD even after sterilisation.
>


LOL!!

What kind of cavemen are these guys that they're just now learning
that?

The Province of British Columbia sends all it's CJD cadavers in metal
coffins to either Montreal or Toronto for autopsy.

B.C. knows they don't have the means to sterilize for something that is
nearly indestructible.