Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Mass spectrometry exposes Landis

  1. Aug 1, 2006 #1
    Amazing what some criminals think they can get away with! This guy should have taken more chemistry courses in college. :cool:

    http://www.nytimes.com/2006/08/01/s...&en=3f51b3d7def2bbea&ei=5094&partner=homepage
     
    Last edited: Aug 1, 2006
  2. jcsd
  3. Aug 1, 2006 #2

    Chi Meson

    User Avatar
    Science Advisor
    Homework Helper

    I am sick. I tell you I am so ******* SICK about this! I can't tell you how p****d off I am at the whole thing. Tyler Hamilton doped, and lied about it. Now Landis! And Lance isn't in the clear either especially with Frankie Andreu's statment.

    I tell you, George Hincapie is looking better than ever now simply bcause he DID sag after a valiant start.

    Well anyway, three cheers for Oscar Perriro (assuming he's clean). I hope thay make a special ceremony for him.

    G! D! I!
     
  4. Aug 1, 2006 #3

    BobG

    User Avatar
    Science Advisor
    Homework Helper

    OLN has to be even sicker. With Lance gone, I think they really needed Hamilton, Landis, or Hincapie to come through in order to keep Americans interested. As it is, just about every star in cycling has been wiped out by drug testing, including the two best Americans.

    Cycling looks even dirtier than track and field and baseball. It's starting to look as cheap as weightlifting.
     
  5. Aug 1, 2006 #4

    JasonRox

    User Avatar
    Homework Helper
    Gold Member

    It makes me laugh so much.

    This is what happens when you try to push the limits of your athletes. They just can't keep up after awhile.

    Note: They tested every single guy on the NHL Draft this year and they were all clean. I'm talking everyone and not just random testing. Cheers to the NHL! :approve:
     
  6. Aug 2, 2006 #5

    Astronuc

    User Avatar

    Staff: Mentor

    “I’ve seen bodybuilders with numbers 100 to 1,” Kay said. “Although Floyd’s was elevated, it’s not off the chart or anything.”

    I wonder what Landis's doctor was thinking when he referenced 'bodybuilders'. :rolleyes: This is not helping his case.
     
  7. Aug 2, 2006 #6
    Is this his doctor or his lawyer?

    http://www.nytimes.com/2006/08/02/s...&en=2fc43a3b867cc26d&ei=5094&partner=homepage

    Yes, there's a big uncertainty here, because we all know the sample size of atoms in mass spectrometry is rather small. (*insert sarcastic smilie here*) And of course "only mildly elevated" is a very meaningful, non-deceptive phrase to use, when talking about C13/C12 isotope ratios. (*and here*)
     
  8. Aug 2, 2006 #7

    Moonbear

    User Avatar
    Staff Emeritus
    Science Advisor
    Gold Member

    I still find it strange that he only had a positive result in one urine sample out of all the tests conducted during the Tour. If he was doping, you'd expect to see a consistently elevated ratio in all his samples.

    The isotope test, according to the literature I scanned a few days ago when I first saw this story, seems to be a bit controversial still.

    None of this rules out the first sample being contaminated. If a technician forgot to change the pipet tip after running a reference sample or the high concentration standards, then dipped it into the urine sample, it doesn't matter how many times you re-run it, it's going to keep showing the odd result.

    And, every so often, when running hormone assays, you just get an inexplicably odd result that you know is impossibly high...you just don't get a huge spike in concentrations without a subsequent metabolic decay curve. So, when something goes from baseline, to extremely high, and back to baseline with no intermediate samples between, I'm more suspicious of sample contamination than an actual elevated hormone concentration, either produced naturally or injected.

    On the other hand, if he has been doping, it's not like he's going to just admit it and hand over the title, and it must have been an awfully short-acting form of testosterone, which doesn't really make a lot of sense in an endurance competition.

    I'm also concerned that the biosynthetic pathway of epitestosterone is not known. To use something as a reference value without fully understanding what regulates its synthesis or metabolism is risky.
     
  9. Aug 2, 2006 #8
    What's the controversy about? Is any of this literature publically available?
     
  10. Aug 2, 2006 #9

    Moonbear

    User Avatar
    Staff Emeritus
    Science Advisor
    Gold Member

    It hasn't been tested in a lot of subjects where it's known they were doping or not. As you read through the literature, you'll see results that are outside the normal range in what are supposed to be control subjects dismissed as an athlete who has been doping rather than considering that maybe these occassional odd results are of physiological or pathological origin. I'm having difficulty actually finding studies where they took volunteers who would have no reason to dope (non-athletes) and monitored them pre and post administration of testosterone to validate these tests. Instead, they're taking populations of athletes and using the fact that they find values several standard deviations from the average as evidence that those subjects are doping, even if they deny it.

    There also seem to be a few articles that suggest diet can shift the carbon isotope ratio, especially an abrupt change in diet (such as when one might go to a foreign country and carbo-load before a big competition :rolleyes:).

    Here's one review article that's freely accessible and the bit they have to say on the isotope testing.

    http://www.clinchem.org/cgi/content/full/43/7/1280

    There seems to be a gray area between -27 and -30 as to whether it would be a naturally occurring variation in isotope ratios or due to doping. That may be what they meant by it being only mildly elevated, that it's suspicious, but in the gray area.
     
  11. Aug 2, 2006 #10
    That just means they can't yet detect what the players are taking these days.
     
  12. Aug 2, 2006 #11
    There's more confusion - this study looks at C13/C12 ratios in T. Another study, four years later, looks at C13/C12 ratios in three metabolic byproducts (I think that's what they are), which all have isotope ratios different from each other, and from T:

    http://www.clinchem.org/cgi/content/full/47/2/292
    So it's quite different depending on which carbon atoms they choose to test. I'm not sure what the French lab did, or what numbers it came up with. Is there a standard?

    One clarifcation - the "mildly elevated" quote came from Landis' personal doctor, not from an official source. Just to prevent possible confusion.
     
    Last edited: Aug 2, 2006
  13. Aug 2, 2006 #12
    High levels of testosterone? So we figured out he might be male. :/

    Maybe we should test that guy who recently lifted a car to save a girl and see if he doped.
     
  14. Aug 3, 2006 #13

    Moonbear

    User Avatar
    Staff Emeritus
    Science Advisor
    Gold Member

    Technically, everything measured is a metabolite of T (they don't measure testosterone itself in urine, but a metabolized form).

    That's my question too, and one I haven't found an answer for. I really don't find an amazing number of research papers on this, so it seems more like something with a couple semi-promising articles on it, but far from conclusive, has suddenly found its way into drug testing labs. As far as I'm concerned, these athletes are still part of a big experiment, because I'm just not finding the hard evidence that this is a test proven to be reliable under normal competition conditions.

    I realize that. It's probably the closest we're going to get to a report of the actual test result (I'm sure the media doesn't think anyone would know how to interpret an actual number if they reported it).

    It's certainly all very suspicious, but I'm not ready to hang the guy and strip him of his title just yet. It'll only be a couple days before they have the B sample tested. That's still not foolproof, if the original sample was contaminated before they split it into the A and B sample, or if there is something going on that day to have altered his production or excretion of either testosterone or epitestosterone.
     
  15. Aug 3, 2006 #14

    Chi Meson

    User Avatar
    Science Advisor
    Homework Helper

    Mildly elvated? 11 to 1? A HIGH natural elevation is 2 to 1! The Cycling Federation allows up to 4 to 1.

    I watched Floyd on that 17th stage. He appeared to be greater than Eddie Merckx, Indurain, AND Armstrong that day. The only thing I can say in his defense is:

    If he did KNOWINGLY take testosterone, he should have known that he MUST NOT win that stage sice that would ensure he'd be tested, and ensure he'd be caught. And Floyd is a smart guy, and he had hours to think about it as he soloed over four mountains. That part doesn't make sense to me.
     
  16. Aug 3, 2006 #15

    Moonbear

    User Avatar
    Staff Emeritus
    Science Advisor
    Gold Member

    There are documented cases of people with natural levels as high as 13:1. If he was doping, why wasn't this showing up in all his tests? The whole point of using the elevated ratio is that it's supposed to last longer than the drug itself, so the day after he used, it still should have been somewhat elevated. (And, you'd think someone who is at that level of competition would have the sophistication to know to take T and E together to keep the ratio in check.) But, again, my problem is that they're using as a reference value something that is itself an unknown (epitestosterone). Without knowing the biosynthetic pathway of epitestosterone, there is no way to know if there are conditions (such as extreme exertion over several days of competition) when the natural ratio shifts, perhaps favoring the synthesis of testosterone rather than epitestosterone from the common pre-cursor pregnenolone (that's about all that's known about epitestosterone is that it is synthesized from the precursor pregnenolone, but other steroids can be synthesized in more than one way, so just knowing one precursor doesn't mean you know all there is to know).

    I don't want to come across sounding like I'm trying to defend doping, because I'm not. My concern is more that this test could be coming up with false positives on clean athletes due to lack of understanding of the full synthetic, metabolic and excretory rates of the hormones being tested under different types of competition stresses, while those who want to cheat can still circumvent it (by using both testosterone and epitestosterone to keep the ratio consistent).
     
  17. Aug 3, 2006 #16

    Chi Meson

    User Avatar
    Science Advisor
    Homework Helper

    You're getting my hopes up, Moonb. I'm gonna have to not listen for a while.

    :smiley covering ears: "La la la la la la la la"
     
  18. Aug 3, 2006 #17

    Moonbear

    User Avatar
    Staff Emeritus
    Science Advisor
    Gold Member

    :rofl: Sorry. I'll try not to get your hopes up. Afterall, he hasn't offered to pay me gobs of money to be an expert witness in his defense yet. :tongue2:
     
  19. Aug 3, 2006 #18
    He'll be doing lots of that soon enough. Maybe give him a call?
     
  20. Aug 5, 2006 #19

    Astronuc

    User Avatar

    Staff: Mentor

    On Wikipedia today -
    http://en.wikipedia.org/wiki/2006_Tour_de_France

    http://en.wikipedia.org/wiki/Floyd_Landis

    On Yahoo -
    Landis backup test also positive; Tour de France title in jeopardy
     
  21. Aug 5, 2006 #20
    His choice - he can simply admit he's just another shameless cheat and that he's been publically lying about it for weeks, or he can drag on an endless legal battle claiming he has no idea how he ingested synthetic steroids, until everyone forgets about him. My expectation is he'll choose the latter.
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?



Similar Discussions: Mass spectrometry exposes Landis
Loading...