JPM London said:
Where I come from we don't call that a steak - that's a bite...
I know Conti is not the biggest guy around, but considering these guys consume something like 5000 calories a day during the Tour he'd probably have had seconds and thirds if that's the steak size.
Fair enough, that's just the figure the blogger used. How about 300 g? That's more than half a pound, and 1200 calories (probably more, as the meat is sure to contain some fat). I assume most of the calories these racers consume are still carbs?
Using the 540 ng figure, to get that much CB from 300 g of meat, the meat would have to contain at least 1.8 ug/kg. In the last study of Mexican meat I cited, 90% of the samples had a level of 1.8 ug/kg or LESS.
To be fair about this, 540 ng is also pushing the limits of transfusion. It appears one would have to use 80 ug CB daily for several days, then withdraw 500 ml. of blood, all transfused at one time. Very possible, but I'm thinking unlikely. In any case, both the transfusion scenario and the meat contamination scenario do put limits on how much CB Bert originally ingested. Either theory is more compatible with somewhat less than 500 ng. About half of that can be easily accounted for by a reasonable CB program and a reasonable withdrawal/transfusion. That number is still inconsistent with eating meat that passed inspection, but at least some meat that did not pass inspection could yield it.
i actually read martin budden's blog many months ago. he makes a nice effort. his math skills are solid but by his own admission his knowledge of physiology, doping methods, and testing protocols are inadequate.
For the transfusion scenario, Martin's calculations can be simplified. He uses three different formulas to model the CB concentration in blood, but these are clearly based on food absorption, which as you say, is different from transfusion, where everything goes into the blood itself. He only needs the last of the three formulas, which models the decrease of CB in plasma as it is filtered out of the blood.
He also takes into account that only a fraction of the CB dose (20%) accumulates in the urine after 72 hours. But this, again, is to a large extent because the CB is taken orally and absorbed gradually. As he notes, CB taken orally reaches a plateau in blood levels which is maintained for several hours. During this period, much of it is absorbed by the tissues, and does not appear in the urine until much later. In contrast, if CB enters the blood by transfusion, it is falling off in concentration immediately as it goes into the urine. IOW, the blood concentration at which clearing begins is higher relative to the initial dose for transfusion.
Taking these factors into account, I estimate 70-250 ng CB initial dose, depending on half-life (30-35 hours), urine flow (30-50 ml), and how long after transfusion the urine sample was taken (6-24 hours). I also note that the calf studies indicate a very large variation in urine CB levels, not only between individuals, but within one individual over time.
then, testing negative for clenbuterol short time before the tour is not a crucial piece of evidence in contador's favour as it regards humo article accusations.
it may however help him in showing that he did not have a transfusion before the tour start as was typical of some other blood doping programmes that became public knowledge. i see limited value then.
Bert aside, would a rider transfuse twice during the Tour? If he did, and did not use frozen cells, he would have to withdraw enough for two transfusions just a couple weeks before the first transfusion. So I guess he would withdraw 500 ml and transfuse half of that each time? I can't imagine withdrawing more than 500 ml, particularly so close to the beginning of the biggest race of the season.
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