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02-10.-2004, 01:30 PM
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#301 | |||||||
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Registered User
Join Date: Jun 2003
Posts: 246
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Re: **** Breaking News: Hamilton Tested Positive? ***
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I'll answer #1 indirectly: I don't believe there is any "false positive" because this is a threshold test. They claim that the test has a lower limit of detection of approximately 5% of the total RBC count. So if Hamilton had less than 5% "foreign" RBCs, then he would not have failed the test. As you might have read in the original haemotologica article: Quote:
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The answer to #3 is 12 of them, not declared specifically and on purpose. Since normal blood transfusions are not typed for minor antigens they do not want blood dopers to know specifically which minor antigens, or groups of antigens, or antisera that they use in the test. Quote:
To sum up: Quote:
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02-10.-2004, 04:20 PM
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#302 | |
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Registered User
Join Date: Aug 2003
Location: New Brunswick, Canada
Posts: 514
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Re: **** Breaking News: Hamilton Tested Positive? ***
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Yes, the test is sensitive. Is it accurate? The 2003 article is based on a very small sample size -- 25 post surgical patients. Samples were drawn immediately after transfusion. No demonstration that the supposition that sample dilution mimics elapsed time. Why would I ask the question about antigen stability? In spite of your "witticism", antigen stability is a storage issue, at least according to the transfusion protocol guidelines I have read. I am inquiring as to if there are any physiological basis for instability in these carbohydrates on the blood cell membrane. I don't know. It's why I asked the question. If you have an answer that you are willing to share, it would be appreciated. If you don't have the answer to the question, that's fine. Thank you.
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Insanity has its price -- Please have exact change. |
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02-10.-2004, 04:45 PM
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#303 | |
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Registered User
Join Date: Mar 2004
Location: Northern California
Posts: 369
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Re: **** Breaking News: Hamilton Tested Positive? ***
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Fair enough Perro Loco! I just hope that just because some dope themselves we don't stop being cycling fans. Remember not all do it and You are Innocent until proven 100& guilty right? Have a coll weekend! and do not forget to keep riding like a dream! I read that quote somewhere here in these forums... I thought it was preety cool! |
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03-10.-2004, 01:42 AM
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#304 | ||
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Registered User
Join Date: Jun 2003
Posts: 246
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Re: **** Breaking News: Hamilton Tested Positive? ***
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03-10.-2004, 02:53 AM
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#305 | |
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Registered User
Join Date: Feb 2004
Posts: 277
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Re: **** Breaking News: Hamilton Tested Positive? ***
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I don't know the answers to any of these questions since I admit I am a dunce when it comes to science. And even if I did know these answers, I don't have the scientific expertise to place them in context. The test was developed by scientists with decades of experience in hematology or other sciences. The test met the requirements set out by WADA for the test to be implemented. WADA is staffed by scientists and others with years of experience in sport and doping. I am relying to an extent on the fact that the people involved in this test are people of integrity and knowledge. Are these valid questions? Absolutely. And I totally believe that the soundness of the test should be subject to scrutiny. If this test turns out to be unsound, then I think WADA deserves criticism for approving the test. Tyler will have his chance to defend himself and will have a team of legal and scientific experts questioning the validity of the test. When it comes to science I rely on the expertise of individuals. I am in no position to second guess scientists who have decades of education and experience under their belts. To do so would be presumptuous. I would be interested to hear the opinions of others in the scientific community who have expertise in this matter. And by that I don't mean the fangirl letters in the Velonews mailbox. It sounds like you have a scientific background or an interest in it. Can you provide us with answers and place these answers in context for us? For example on the issue of false positives - how do you explain a false positive on three different tests? Now I know that you will argue that the IOC A sample is moot since it could not be confirmed. But for the sake of argument, how could a false positive of IOC A and Vuelta A&B occur? If the test is not sound, then why was only Tyler a positive? If the test was not sound, how could the restults be consistent when the test was performed by two different testing bodies? I'm not being argumentative, these are sincere questions I have. |
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03-10.-2004, 03:10 AM
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#306 |
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Registered User
Join Date: Feb 2004
Posts: 277
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Re: **** Breaking News: Hamilton Tested Positive? ***
Just to clarify an earlier post I wrote about "wasting bandwidth". This was in reference to someone who was posting a rather condescending preamble and postamble to every post about respecting people's opinions etc. It was not in reference to people expressing support for Tyler. I apologize if my post was rather harsh - this can happen when one writes late at night after watching presidential debates and drinking vodka.
I think there is room for doubt in this case as this is a new procedure and there have been valid questions raised about the test. I don’t have a problem with people expressing their support for Tyler. I do however have a problem when people couple this opinion with contempt for others who are basing their opinions on the (very damning) evidence to date. It is unbelievably hypocritical to say that others are rushing to judgment about Tyler and in the same breath make allegations about UCI/IOC/WADA involvement in conspiracies, collusion, and outright negligence without any evidence whatsoever. If you’re going to be a stickler for evidence and due process then that cuts both ways. I especially am defensive about Dick Pound. I have read a lot about him. He has been involved in sport administration for a long time and he is a former olympic athlete. Everything in his background and his actions indicate that he is a man of extreme integrity. He believes strongly in the concept of fair play. He is perfect for WADA and if he needs to put the scare into dopers then so be it. |
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03-10.-2004, 04:51 AM
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#307 | |
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Registered User
Join Date: Aug 2003
Location: New Brunswick, Canada
Posts: 514
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Re: **** Breaking News: Hamilton Tested Positive? ***
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My answer to all 4 questions I posted is "I don't know". I do not know the false positive rate on this test. I would like to know what it is. In the 2003 article, using 25 test subjects, they determine there were no false positives in this test run. Is this true for a large test population? I don't know. Hence my question. Have the authors or other replicated these tests on larger populations or is the determination that there are no false positives based entirely on the 25 test subjects in the 2003 article? I don't know. Of the several hundred minor blood antigens, why were these 12 chosen over any other group? I don't know the answer to that. I suspect it might have to do with how frequently they are distributed across varying populations. I don't know. Actually, it sounds like they've got a list of 20 and can "pick & choose" from that list. Is this an accurate interpretation?? I don't know. I'm trying to figure it out. As far as Hamilton's test results, I can't fully figure out the test, let alone nitpick his, since the data hasn't been published to my knowledge. Is Tyler Hamilton guilty of blood doping? I don't know. I don't know the guy from Adam. I am, however, willing to listen to his side of the story if and when it comes out. I am curious as to the science behind the test. I have questions, although I appreciate this is not the appropriate forum for those questions.
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Insanity has its price -- Please have exact change. |
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03-10.-2004, 05:15 AM
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#308 | |
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Registered User
Join Date: Aug 2003
Location: New Brunswick, Canada
Posts: 514
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Re: **** Breaking News: Hamilton Tested Positive? ***
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I'm the mystery condescending "someone" .... for what it's worth, my condescending, looking for a fight, etc etc etc etc. comments were actually my attempt to be polite and not get suckered into the slagging match I'd lowered myself to the night before. I have certain standards that I aim for but unfortunately don't always keep. The night previously, I had lowered myself to the same mudslinging wretchedness that some people, quite often but not always men, use to stifle debate and discussion. I didn't meet that standard I hope for myself. I did delete my more ridiculous snipes but that doesn't eliminate the fact that I shouldn't have made them in the first place. Debate ideas; not people. I didn't do that and that was wrong of me. If you want to call me condescending because I made an attempt to be polite -- have at it. All the rest of the names you've called me, fill your boots. I have rather strong, and probably equally erroneous, opinions about you too.
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Insanity has its price -- Please have exact change. |
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03-10.-2004, 05:22 AM
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#309 | |
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Registered User
Join Date: Feb 2003
Posts: 696
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Re: **** Breaking News: Hamilton Tested Positive? ***
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BK, a genuine conspiracy theorist sincerely believes a good conspiracy cannot be proved. But that mainly relates to their paranoia which those theorists are burdened. Firstly, we have you alluding to a conspiracy between the accredited lab who had undertaken over 3,000 tests during the Olympics (and not knowing the identity of the donors), the IOC and the UCI. Having failed there you have widened your conspiracy net to embrace scientists who established the tests and by your questions you are implying they are flawed. You suddenly appear with questions of a complex nature to a layperson forum that are incongruous with the simplicity and naivety of your prior allegations to suggest you are educated/trained/experienced in molecular biology. BK, what are your qualifications in this field to be addressing these high brow questions to this Forum? Did you lift these questions from another forum submitted by a TH supporter and medical practitioner ?
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VF "Remember, even if you win the rat race, you are still a rat" |
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03-10.-2004, 07:06 AM
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#310 | |
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Registered User
Join Date: Aug 2003
Location: New Brunswick, Canada
Posts: 514
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Re: **** Breaking News: Hamilton Tested Positive? ***
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I asked the question about the practice of communications between labs. You straightened me out. I took your answer at face value and thank you. I have no valid qualifications by which I can substantiate or justify asking questions. I'm rather surprised at this requirement. And any training I may have enjoyed in molecular biology I'm afraid is 20 years old -- at least 20 yrs old. Some of it is probably closer to 25 yrs old, in the interests of full disclosure on the matter. In any event, Veloflash, you are quite correct. This is no place to be asking questions on the nature of the test and I stand quite corrected on the matter. And, no, I actually don't believe in conspiracies driven by malice and paranoia. There's no requirement for malice for things to fall off the track. Simple human nature is sometimes sufficient. This is not based on any credentials found in an university classroom or in a textbook. It's an observation based on 17 years of service in the criminal justice system which has occasionally, with all the checks and balances and procedures and protocols and precedent and etc, has wrongfully convicted innocent men of crimes for which they were jailed, or in some jurisdictions, actually executed. But this bit of antidotal stuff is really off topic and not pertinent to the matter at hand and certainly doesn't qualify me in any way, shape or form to be asking questions of a science based nature.
__________________
Insanity has its price -- Please have exact change. |
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03-10.-2004, 09:19 AM
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#311 | |
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Registered User
Join Date: Mar 2004
Location: Northern California
Posts: 369
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Re: **** Breaking News: Hamilton Tested Positive? ***
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I'd like to read that material too......  |
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03-10.-2004, 09:40 AM
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#312 | |
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Registered User
Join Date: Aug 2003
Location: New Brunswick, Canada
Posts: 514
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Re: **** Breaking News: Hamilton Tested Positive? ***
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It's a straight up question. Antigens can become unstable **out of the body** depending on storage conditions...stands to reason, doesn't it, if the blood is deteriorating, oxidizing, rotting, decomposing or whatever it is that blood does when it's not kept cold, the antigens are also destroyed along with the rest of the cells. So, my question is whether anyone knows of a means, process, disease, condition etc etc etc etc which may possibly cause the antigens to become unstable inside the body. It's a question. It is NOT a statement of fact. It is not a theory. It is not a conspiracy. It is a QUESTION derived from the fact that I don't know the answer. I asked it on this board because there are a lot of knowledgeable people here and one of them might have been willing to point me in the right direction. And no, I'm sorry, I do not have a URL or a refererence to back up my question. I honestly had no idea that a requirement to reference queries was a consideration. All questions are hereby withdrawn. Thanks.
__________________
Insanity has its price -- Please have exact change. |
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03-10.-2004, 11:03 AM
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#313 | |
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Registered User
Join Date: Feb 2004
Posts: 277
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Re: **** Breaking News: Hamilton Tested Positive? ***
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Who has tried to stifle debate on this thread? Virtually all the discussion on this thread has been about ideas and the content of people's posts. You seem to perceive any debate about the content of your posts as personal attacks. Antoineg and I were debating your allegation that Mr. Pound's opinions somehow affected the testing results, and you copped an attitude even though it was about content. And are you implying that us men are "attacking" you because you are female? And I really don't care what an online stranger thinks of me. If you thought I was the devil himself, it wouldn't bother me in the slightest. Actually I would be quite flattered. Anyway, I agree that that the discussion should be about ideas. But if one puts forth a contrarian viewpoint then you have to expect that others may be critical of it. But you are right that things should not get personal and I was certainly offside in making the comments I made. |
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03-10.-2004, 01:14 PM
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#314 | |
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Registered User
Join Date: Jun 2003
Posts: 246
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Re: **** Breaking News: Hamilton Tested Positive? ***
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Do people change blood types when they work out? Do type-A people become type-O people? Answer this question and you'll answer your previous question, because these minor blood groups are determined physiologically in the same way that the "major" A, B, AB, and O groups. Each RBC has certain antigens that determine the blood type, and each person has a certain RBC profile that determines their type -- which includes these new minor blood groups that we're now discussing. |
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04-10.-2004, 03:40 AM
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#315 | |
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Registered User
Join Date: Sep 2004
Posts: 217
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Re: **** Breaking News: Hamilton Tested Positive? ***
Kate:
Your questions are absolutely fair, as well as relevant. Based on the information I've been able to gather, here are the best answers I'm able to supply: (1) I haven't been able to find any published claim for a numerical likelihood of false positives, other than Dr. Ashenden's categorical rejection of any such possibility (from www.cyclingnews.com "There's no way ... for an individual to have a mixture of red blood cells from different minor blood groups, other than for him to have had a transfusion."). If any substantial empirical study had been conducted to estabish this number experimentally, it seems reasonable that these results would have been quoted by now. It seems as if Dr. Ashenden's position is based on analytical considerations of blood phisiology, as oposed to experimental demonstrations. Having said that, there were several hundred (I've seen the number 300 on this measge board) other riders tested and none were positive except for Tyler. If we assume that the other riders were in fact not blood doping, then the rate of false positives is somewhere between 0% and 0.3% (i.e., 0/300 or 1/300). As this test is applied more widely at future events, the statistical occurence of positive reults (false or otherwise) will be established further. (2) So far, it appears the false positive rate can be estimated by (a)predictions based on analytical considerations (b) an extremely small intial sample group, and (c) two larger sample groups of several hundred riders each (3) The antigens that are used have not been revealed, and that seems like a reasonable position for an test lab to take. Otherwise, cheaters really would be able to beat the system. (4) Good question, and the answer may not be known. However, it's safe to conclude that the other 300+ cyclists who've taken this test have all been physiologically stressed. I'm sure there are cyclists in the professional peleton whose competition schedules are even more demanding than those of a star like Tyler. If Tyler failed the test becuase his antigens somehow change in response to physiological stress, he's the only one among several hundred riders who's shown that capacity. Let me say that I've been a huge fan of Tyler and I hope this all works out for him somehow. However, a test with at least 99.7% safeguard against false positives seems very compeling to me. If he's a cheat, as the current evidence seems to strongly suggest, then he desrves all our scorn. Quote:
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