Re: Landis B sample positve.

Quoted message said:

jim schreef:

Quoted message said:

And note that it is exogenous

I'm a bit medically challenged, so does this mean 'not produced by his
own body'?

"exo" = "outside of" (eg: exoskeleton), so pretty much, yes.

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So what are the 'legitimate' ways one can get exogenous hormones in one's
body? Other than 'included twin syndrome' that is?

"Stuart Lamble" <[email hidden]> wrote in message
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Quoted message said:

Quoted message said:

jim schreef:

Quoted message said:

And note that it is exogenous

I'm a bit medically challenged, so does this mean 'not produced by his
own body'?

"exo" = "outside of" (eg: exoskeleton), so pretty much, yes.

--
My Usenet From: address now expires after two weeks. If you email me, and
the mail bounces, try changing the bit before the "@ to usenet".

jim said:

So what are the 'legitimate' ways one can get exogenous hormones in one's body? Other than 'included twin syndrome' that is?

Hrrmmm, any Endocrinologists out there in a.b land who can explain this point in layman's terms?

http://www.cyclingnews.com/news.php?id=news/2006/aug06/aug05news2

" .. Landis' legal team criticised the UCI for announcing the results of the A sample without knowing the B sample result, believing that Landis' rights had been violated. They have also claimed that his high T:E ratio arose from natural causes, and that the IRMS test, that showed exogenous tesosterone, is "unreliable". However, anti-doping experts such as Christiane Ayotte, director of the anti-doping lab in Montreal, Canada, have strongly defended their testing methods .."

cfsmtb said:

Hrrmmm, any Endocrinologists out there in a.b land who can explain this point in layman's terms? "

I have been in that area although I am not working there presently.

Doing a quick google I saw that the testosterone administered via patches is modified by enzymes in the skin as it is absorbed. If the test used has an MS (Mass spectrometry) detector in the protocol - which I would expect as they are common as mud these days - I would expect that the modification should be fairly easily detectable.

But, the testing systems seem to be somewhat complicated in that they are often looking for breakdown products of the banned substance. The differences in the breakdown products between the internally produced, and the trans-dermally adsorbed materials may not be that great.

The other aspect may be alterations in the natural hormone ratios. the T/E ratio is probably one aspect of this. It may be that artifically administered (modified) testosterone alters the natural ratios in a different way to a natural over-production of internally generated testosterone.

The other feature of alterations in the ratios is that they may be an indicator of prolonged use of external steroids as the changes take time to occur.

RoryW

"jim" <[email hidden]> wrote in message
news:[email hidden]...

Quoted message said:

So what are the 'legitimate' ways one can get exogenous hormones in one's
body? Other than 'included twin syndrome' that is?

Can't?
I thought the 'exogenous' (substitute) testosterone is made from plants,
which is why there's a different type of carbon atoms in it?

cfsmtb said:

jim said:

So what are the 'legitimate' ways one can get exogenous hormones in
one's body? Other than 'included twin syndrome' that is?

Hrrmmm, any Endocrinologists out there in a.b land who can explain this
point in layman's terms?

Does this help? If not, let me know which bits aren't clear and I'll
tweak it:

http://www.cyclingnews.com/news.php?id=features/2006/testosterone_testing

John Stevenson said:

Does this help? If not, let me know which bits aren't clear and I'll
tweak it:

http://www.cyclingnews.com/news.php?id=features/2006/testosterone_testing

Much appreciated for the links Rory and John. 😉

jim said:

Firstly, from what I read, it seems that an elevated T:E ratio on its
own is not damning evidence. Even results at the extremes of the
distribution curve can be naturally occuring - but may need to be
supported by a subsequent endocrine tests. Correct???

That's the theory. Landis has some health issues which *potentially*
could cause weirdness in various blood chemistries.

Quoted message said:

Secondly (and this is where it gets a bit obscure for me) an IRMS test
can identify the presence of carbon isotopes that do not naturally occur
in human testosterone. So if an IRMS test has been conducted and a
non-naturally occuring isotope is detected does this mean 'go directly
to goal'? If it dosen't mean 'gdtg' what constitutes 'get out of goal
free' evidence?

The current strategy seems to be "damn the test". That is, suggest the
test is inaccurate or sufficiently likely to give a flase positive that
its results are not conclusive.

--
Dave Hughes | [email hidden]
I think it's a beautiful day to go to the zoo and feed the ducks.
To the lions. -- Brian Kantor

Thanks for the informative responses. I still have the confusion of the lay
observer.

Firstly, from what I read, it seems that an elevated T:E ratio on its own is
not damning evidence. Even results at the extremes of the distribution
curve can be naturally occuring - but may need to be supported by a
subsequent endocrine tests. Correct???

Secondly (and this is where it gets a bit obscure for me) an IRMS test can
identify the presence of carbon isotopes that do not naturally occur in
human testosterone. So if an IRMS test has been conducted and a
non-naturally occuring isotope is detected does this mean 'go directly to
goal'? If it dosen't mean 'gdtg' what constitutes 'get out of goal free'
evidence?

Thanks for any light shone on this matter.

"John Stevenson" <[email hidden]> wrote in message
news:[email hidden]...

Quoted message said:

cfsmtb said:

jim said:

So what are the 'legitimate' ways one can get exogenous hormones in
one's body? Other than 'included twin syndrome' that is?

Hrrmmm, any Endocrinologists out there in a.b land who can explain this
point in layman's terms?

Does this help? If not, let me know which bits aren't clear and I'll tweak
it:

http://www.cyclingnews.com/news.php?id=features/2006/testosterone_testing

[quote="jim"]Thanks for the informative responses. I still have the confusion of the lay
observer.


Secondly (and this is where it gets a bit obscure for me) an IRMS test can
identify the presence of carbon isotopes that do not naturally occur in
human testosterone.
Thanks for any light shone on this matter.
[QUOTE]

My interest was piqued by the isotope story so I have both conversed with my local GS-MS expert and looked at the WWW.

I was not aware of this but the presence of a heavier isotope (say C13 compared to C12) can alter the rate of a biochemical reaction and over time this can cause the different isotopes to accumulate in different ways. There is also a diference in the way that soy plants (and other 'tropical' plants) accumulate the different isotopes because they run a different photosynthetic pathway to temperate climate plants. This gives rise to the differences in the levels of C13. The precoursers of synthetic testosterone are typically from soy.

Read about it at: http://pipeline.corante.com/archives/2006/08/01/testosterone_carbon_isotopes_and_floyd_landis.php

To me it seems that the natural levels of C13 in a human could vary depending on the types of plants from which the human has obtained the carbon to synthesise their endogenous testosterone - if you exclusively ate tropical plants or animals that consumed tropical plants presumably it would skew the results - This could be a flaw in the test, but presumably someone has thought of it.

On the analysis side my resident expert tells me the GC-MS techniques are very solid. Isotopic differences will show up in the MS detector and they may also show up the the GC separaration.

Getting a bit in-depth here, but the photosynthetic effect was interesting. It feeds into a whole range of things.

RoryW