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Background read on Blood Doping.

Discussion in 'Pro Cycling (Road and Track Racing)' started by Tim Bennet., 25 Jul 2007.

  1. Tim Bennet.

    Tim Bennet. Entirely Average Member

    Location:
    S of Kendal
    This is from Velonews and was first put up after the Tyler Hamilton case.

    ********
    A doctor explains blood doping
    By Shannon Sovndal, M.D.


    The following story first appeared on VeloNews.com in connection with the Tyler Hamilton blood doping case in September of 2004. On Tuesday, Astana's Alexander Vinokourov joined Hamilton and Santiago Perez as the only riders ever to test positive for homolgous blood doping using a test developed by Australian researchers at Science and Industry Against Blood-doping.
    ------------------------------------------------------------------------
    How times change. Just last week, EPO was the talk of the town. Now you can't open the sports page without reading something about transfusion blood doping. Sport doping is going old school. Out with the new, in with the old.



    Blood transfusions have long been used to enhance athletic performance. Transfusions are an extremely straightforward, simple, and effective method of increasing the blood's oxygen carrying capacity. Physiologists believe that it is the rate at which hemoglobin delivers oxygen to the exercising muscle that limits muscle performance. Blood transfusions address this limitation by increasing the number of hemoglobin molecules carrying oxygen to the muscles.

    The term "blood doping" refers to various techniques used to increase the oxygen carrying capacity of blood. Recently, recombinant human erythropoietin, more commonly known as "EPO", has been the drug of choice. However, with the advent of more effective and inclusive testing, the use of EPO has become more difficult and complex.

    Because of the increased risk of detection, there has been concern that athletes may turn to an older form of blood doping that, until recently, has been virtually undetectable. This basic performance enhancing use of blood transfusions is at the center of the recent doping controversy involving rider Tyler Hamilton.

    Homologous versus autologous
    There are two methods of doping through blood transfusions: autologous and homologous. With an autologous transfusion, an athlete receives his or her own blood. An athlete donates blood, stores it, and then receives the blood at a later point in time. The advantages of this technique are the avoidance of diseases such as HIV or hepatitis, the reduction of the risk of detection through testing, and the alleviation of potentially deadly transfusion reactions.

    The downside of autologous doping is that it takes time for the body to recover from the loss of blood that occurs during donation. It would be hard to train effectively while having to donate a supply of blood sufficient to enhance performance. In a homologous transfusion, the blood comes from another person. The benefit of homologous transfusion is no decrease in performance during the donation period. However, the disadvantages are the risk of contracting blood born diseases, the risk of transfusion reactions, and increased transfusion sensitivity.

    Homologous transfusion is now the focal point of the current doping controversy. All individuals have a specific and consistent genetically programmed blood type. Each blood cell in the body has markers or antigens that hang off the cells. These specific antigens determine an individual's blood type. The major blood types are A, B, and O. The positive or negative value added to the ABO type refers to another antigen on the blood cell called Rh(d). If you have both the A antigen and the Rh(d) antigen, your blood type is A positive. In addition to these major antigens, there are numerous other "lesser" antigens that make up each person's blood composition. It is possible to test not only for one's major blood type (A+ or O-, for instance) but also for the lesser antigens on one's blood cell. By this test, we can define even more specifically the makeup of an individual's blood.

    Markers
    Researchers have now applied this test to the war on doping. A scientific paper written by Nelson, et al., and published in the journal Haematologica explains the new test in more detail. But, because of the subject matter, the article gets a bit technical. I will try to explain the test using as little medical jargon as possible.

    Every red blood cell has a consistent and specific set of blood group antigens. When these antigens are tagged with fluorescent dyes, a machine known as a flow cytometer can differentiate cells with different sets of antigens. Based on the blood being tested, a certain set of antigens is marked, and the cells are placed in the flow cytometer.

    A large number of cells, 50,000-60,000, are shuffled into a single-file line and moved through a detection tube. A laser illuminates the fluorescent tags and sensors sort the cells depending on which antigens light up. The machine produces a graphical picture of the findings, and for any individual person, a single spike representing their inherent antigen set appears on the paper. If a person has received even a small amount of homologous transfused blood, a second, smaller spike representing another antigen set also appears, and the test is "positive" for doping.

    This procedure may sound complex and fraught with errors, but flow cytometry is nothing new to medicine or science and has been used for a long time with accurate results in many applications.

    Does it work?
    The research study mentioned above tested the process on 25 patients and was 100-percent accurate. Still, many question the validity and applicability of the test. Should the group of test subjects be larger? Should the test subjects be elite cyclists? Should a large sample of people not receiving transfusions be tested to look for false positives? (A false positive occurs when the test reads positive, but the athlete has not been doping.)

    The answer to all these questions would seem to be yes. However, in defense of the test, flow cytometry does work. Hundreds of athletes have been tested using this technique and only a few positives have been found. It is also possible that additional research was completed internally by the drug testing organization prior to the test's use. It would seem that at the very least, this test is a good screening test.

    While a screening test is extremely good at catching all individuals doping, it does run the risk of having false positives. The next step in a thorough investigation would be a confirmatory test. This mirrors the procedure for HIV testing in the hospital. If the screening test is positive for HIV, a second, more specific test is completed to confirm the diagnosis.

    Confirmation?
    The problem is, there is no easy confirmatory test. A first thought is to evaluate the blood sample for a DNA. Every person has a totally unique DNA program that can be differentiated from every other person. However, testing a blood sample with only a small fraction of homologous blood could be tricky. If, by chance, the sample used for the test didn't contain the donated blood, the result would show only the DNA of the tested individual.

    This is called preferential amplification. There are tests available that can avoid this problem, but they are complicated and pricey. Many of these methods have certainly been tested in the field of criminology, but as evidenced by the OJ Simpson case, a definitive and convincing answer is often elusive.

    Before these tests could be used to prove doping occurred, research studies would need to be performed specifically addressing this situation. A simpler suggestion, but by no means foolproof, would be to repeat the flow cytometry test again at a later date. Red blood cells have a lifespan of 120 days. If the test is run at 60, 90, and 120 days, the transfused red blood cells should slowly disappear, leaving only the athlete's cells on the test. The only way to keep these cells from diminishing would be to continue to transfuse the exact same blood supply the athlete previously received. It is plausible the athlete could do this, but it would be complicated, especially during the scrutiny of an investigation.

    Athletes these days are often put through the ringer by the drug testing agencies. Their lives are disrupted frequently, even if they never test positive. Since a positive test will likely ruin an athlete's career, there should be no doubt when delivering a positive test verdict. I have long been a fan of cycling, and am sorry to continually read about new doping scandals. I never thought I'd need my medical degree just to figure out the technology behind the latest and greatest doping techniques.

    Over the years I have learned to trust the scientific method and analyze the research data with as little bias as possible. However, in this case, as a longtime fan of Tyler Hamilton, I hope the available data is incorrectly pointing to a conclusion that is ultimately untrue.
     
  2. Tetedelacourse

    Tetedelacourse New Member

    Location:
    Rosyth
    Thanks Tim.
     
  3. Steve Austin

    Steve Austin The Marmalade Kid

    Location:
    Mlehworld
    'geek' thats quite interesting. 'geek'

    :biggrin:
     
  4. chris42

    chris42 New Member

    Location:
    Deal, Kent
    :biggrin: my brain hurts.
    I'll read this at home tonight I think rather than trying to do it while at work.

    Cheers
     
  5. Blonde

    Blonde New Member

    Location:
    Bury, Lancashire
    I suppose homologous transfusions increase the risk of contracting HIV - is this why it is banned? But why is the other method banned? It's not actually using any performance enhancing drugs, so why, and when was it first banned? What makes it different to using any 'legal' method of enhancing performance?
     
  6. Tetedelacourse

    Tetedelacourse New Member

    Location:
    Rosyth
    It only increases HIV risk if the donor has it!

    It's designed to unnaturally enhance performance (because you're altering your system by introducing something to it that wasn't already there). The net result is no different to using EPO - an increase in the blood's ability to transport oxygen to the muscles. Different methods designed to produce the same effect, and both certainly outside of the spirit of competition.
     
  7. Steve Austin

    Steve Austin The Marmalade Kid

    Location:
    Mlehworld
    It banned because a rider could go to altitude and train. give blood, store it and replace this when needed. This blood would have all the benefits of having trained at altitude ie high oxygen levels.
    This is what i was led to believe anyway
     
  8. Blonde

    Blonde New Member

    Location:
    Bury, Lancashire
    S.A.'s reasoning makes the most sense to me - If you're using your own blood then it was already there and isn't adding anything. I can see that it's unfair to those who can't do it and obvisouly there's nothing to stop riders training at altitude to produce the same results. Does still seem a bit arbitary though. It's the old argument about teams not being able to afford things I suppose, and therefore those with cash get an unfair advantage as they can afford these procedures etc. But then the same also applies to bikes, equipment, nutrition, doctors and coaches/trainers etc anyway, so I'm still not all that convinced as to why it should be banned. Still, if it's banned, it's banned.

    I just hope that athletes who have used someone elses blood, received some that was not infected with a blood borne disease and that needles used were sterile. Worrying though. Perhaps it should be 'legal', regulated, and therefore relatively 'safe', so that there would be far less risk of this. You're never going to stop people doing it anyway.
     
  9. k-dog

    k-dog New Member

    It's banned because it's cheating - you remove the blood and then over the next while your body replaces it and then you put the original stuff back in and you have more oxygen carrying capability.

    So, same results as EPO as already said - but undetectable - that's why they brought in the haematocrit level limit. In Vino's case they are saying it was a positive result for someone else's blood I think - you can look for this.
     
  10. Blonde

    Blonde New Member

    Location:
    Bury, Lancashire
    Isn't it the other way about? It is considered to be 'cheating' because it has been banned. Just wondered why exactly though. But then I am not of an anti-drugs opinion either. It comes down to the argument that using them gives some teams an unfair advantage over others as not all can afford them. If everything was available to everybody and it was down to individual choice whether to use certain drugs or procedures that would seem fair. You could argue that this would mean all athletes would get pressurised into using a certain a drug or procedure, but I think they already are anyway.
     
  11. fuzzy29

    fuzzy29 New Member

    Location:
    Somerset
    I find it a shame that an interest in professional cycling makes you an expert in unusual medical practices.
     
  12. OP
    OP
    Tim Bennet.

    Tim Bennet. Entirely Average Member

    Location:
    S of Kendal
    Despite by skepticism, I don't actually think every athlete is on drugs, although some days (today?) it's harder to believe that than on others.

    However if even only autologous blood transfusions were allowed it would mean that everyone would then have to do it, as it gives such a massive advantage in aerobic endurance events.

    So even if you regulated it sufficiently to minimise the health risks (thick blood, clotting, etc) and I'm not sure you can totally, you are still left with the image problem: "Hello children. Have you thought about being a professional cyclist? It's a good life as between lengthy periods spent transfusing blood, we try to find time to ride our bikes".
     
  13. Steve Austin

    Steve Austin The Marmalade Kid

    Location:
    Mlehworld
    wait till we get GENE manipulation into cycling, then we really will see some fun. :biggrin:
     
  14. steviesch

    steviesch Senior Member

    remember it's all just for fun and nobody will get hurt! - i'd like some husky dog for stamina and resistance to cold,plus some killer whale for explosive power...a little splash of something to ensure i still had two legs and could ride a bike...i guess i would still have to do some training...