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From: TSS ()
Date: October 31, 2006 at 5:12 pm PST

In Reply to: FDA 50 STATE EMERGENCY BSE CONFERENCE CALL JANUARY 9, 2001 posted by TSS on October 31, 2006 at 4:57 pm:



Medical Implants Containing Bovine Material

At SEAC 91 (February 2006) the Medicines and Healthcare products

Regulatory Agency (MHRA) asked the committee to consider the

potential BSE risks to humans from medical implants using bovine

material from the USA.

The regulations on medical devices containing animal materials are

based on the principle that TSE risks must be eliminated or reduced as

much as possible and residual risks must be acceptable when weighed

against the benefits to patients. Currently no guidance exists on the

acceptability of TSE risk control measures applied to animal material in

medical devices.

The MHRA requested advice on three 3 issues. (i) can TSE risk

associated with medical implants using USA sourced bovine material be

estimated given that it might vary over time? (ii) is there, or has there

been a significant risk that might warrant action in addition to that

already taken? (iii) can the standards that support the regulations be

altered to facilitate a consistent approach about the acceptability of


The committee concluded that:

• a risk assessment should be conducted on each device because

of the large number of variables that influence associated TSE


Key factors which should be considered when assessing risks are:

• the animal source. Use of material from closed herds or from

herds that are managed carefully to prevent the introduction of

the BSE agent.

• use of material from young animals would markedly lower risk

compared with older animals.

• the geographical risk of BSE. The geographical BSE risk

status of a country gives an imprecise indication of BSE risk. It

would be better to use an estimated prevalence of BSE in a

country based on data from a robust surveillance system.

• the potential TSE infectivity of the source tissue(s) based on a

careful assessment of the available data on tissue infectivity.



• the site of implantation. Sites with contact with the blood supply

or CNS may increase risk.

• whether TSE testing is undertaken on the source animal(s).

• the number of source animals used for each device.




Conformation-dependent immunoassay (CDI) for abnormal prions

At SEAC 88 (June 2005), SEAC commented on a recent paper11 which

had reported that the conformation-dependent immunoassay (CDI) for

abnormal prions was more sensitive than other biochemical tests.

The committee:

• commented that, unlike most biochemical tests, it did not rely on

proteinase K (PK) digestion of prions and could detect PK

sensitive forms of abnormal prions.

• expressed caution about the assumption that the test was

capable of measuring the infectious agent, as the form of prion

constituting the infectious agent was still unclear.

11 Safar et al. (2005) Diagnosis of human prion disease. Proc. Natl. Acad. Sci. U S A. 102,



5. Dr Brian Matthews noted that the available information on the

incidence of CJD in various countries, other than the UK, indicates

that there is no obvious decline in the numbers of cases being

reported. However, in the UK there seems to have been a steady

decline in the number of suspected cases, and therefore of

confirmed cases, for the past several years. He asked 3

questions: (i) What are the causes of the decline in the number of

suspected cases reported in the UK over the past few years? (ii)

What is the effect of this decline in reports of suspected cases on

the certainty of the decline of the number of new cases of vCJD

reported in the UK? (iii) What is the effect of this decline in reports

of suspected cases on the certainty that new cases of iatrogenic

transmission of CJD and/or vCJD could be identified?

6. Professor Ironside commented that the number of suspected cases

of sCJD reported each year had varied since surveillance began,

but numbers had appeared to decline in the past 2 years.

However, this was unlikely to be due to significant numbers of

cases being missed. As a way of checking to see if cases had

been missed, NCJDSU had looked back at diagnosed cases of

atypical dementia but had not identified any cases of CJD. The

recent decrease in numbers of suspected cases reported was

therefore probably due to improvements in clinical diagnostic

criteria and the resultant improved quality of referrals. NCJDSU

had very good links with clinicians and pathologists across the UK.

I find this interesting ;

(i) What are the causes of the decline in the number of

suspected cases reported in the UK over the past few years?

(ii) What is the effect of this decline in reports of suspected cases on

the certainty of the decline of the number of new cases of vCJD

reported in the UK?

SO, the cases of nvCJD in the UK went up for years and years and then started declining as with BSE cases due to the feed ban rules, surveillance, eradication, and other factors, and sporadic CJD cases went up and up too, and then started going down at about the same time. interesting? probably just another coincidence ;-) look at Italy in 2005 98 sporadic CJD cases, Germany 81, and France at 81 cases in 2005 as well, all well known BSE countries, all with increases of sporadic CJD since 1993. ...

-------- Original Message -------- Subject: re-BSE prions propagate as

either variant CJD-like or sporadic CJD Date: Thu, 28 Nov 2002 10:23:43

-0000 From: "Asante, Emmanuel A" To:

Dear Terry,

I have been asked by Professor Collinge to respond to your request. I am

a Senior Scientist in the MRC Prion Unit and the lead author on the

paper. I have attached a pdf copy of the paper for your attention. Thank

you for your interest in the paper.

In respect of your first question, the simple answer is, yes. As you

will find in the paper, we have managed to associate the alternate

phenotype to type 2 PrPSc, the commonest sporadic CJD.

It is too early to be able to claim any further sub-classification in

respect of Heidenhain variant CJD or Vicky Rimmer's version. It will

take further studies, which are on-going, to establish if there are

sub-types to our initial finding which we are now reporting. The main

point of the paper is that, as well as leading to the expected new

variant CJD phenotype, BSE transmission to the 129-methionine genotype

can lead to an alternate phenotype which is indistinguishable from type

2 PrPSc.

I hope reading the paper will enlighten you more on the subject. If I

can be of any further assistance please to not hesitate to ask. Best wishes.

Emmanuel Asante

<> ____________________________________

Dr. Emmanuel A Asante MRC Prion Unit & Neurogenetics Dept. Imperial

College School of Medicine (St. Mary's) Norfolk Place, LONDON W2 1PG

Tel: +44 (0)20 7594 3794 Fax: +44 (0)20 7706 3272 email: (until 9/12/02)

New e-mail: (active from now)



full text ;

8. The Secretary of State has a number of licences. We understand that
the inactivated polio vaccine is no longer being used. There is a stock
of smallpox vaccine. We have not been able to determine the source
material. (Made in sheep very unlikely to contain bovine ingredients).

although 176 products do _not_ conform to the CSM/VPC

Terry S. Singeltary Sr.
P.O. Box 42
Bacliff, Texas USA 77518

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