February 11, 2006

The 2006 Winter Olympic Games have just begun, and already athletes have been suspended from competition! An announcement was made on Friday, February 10, 2006 from Pregelato, Italy, where the cross-country ski events are to take place, that eight skiers will beheld back from competition for five days (February 16-20) to undergo additional drug testing.

But why the suspicion? According to the International Ski Federation (ISF), the red blood cell counts for these athletes were unusually high.

Red blood cells (RBCs) are responsible for delivering oxygen to and removing carbon dioxide from working muscles. The more work muscles do, the more oxygen they’ll need; you can imagine that during a cross-country ski competition, athletes’ muscles will be working extremely hard!

Additional drug testing will be done on these eight athletes to determine whether they have been using banned substances, also known as “doping”, to boost their RBCs. One of the compounds that will be measured is a hormone called erythropoietin (EPO).

EPO increases the body’s production of red blood cells, allowing blood to carry more oxygen to the working muscles – a huge advantage in cross-country skiing and other endurance sports. However, the major reason why these athletes are being tested for EPO is because the substance has been banned from national and international sporting competitions, including the Olympics.

EPOs are one of a list of easily identifiable, prohibited substances that have been branded as performance-enhancing drugs and are banned from athletic competitions as part of an initiative to keep sports clean.

Pete Sullivan, an elite distance runner who is training for the Canadian Interuniversity Sports Finals, thinks that drug testing is done adequately in Canada, but he still worries that they are not catching everyone.

“I have been tested twice,” he says, referring to the urine samples asked of him at national competitions, “but I know they wouldn’t catch everyone [doping]”.

The World Anti-Doping Agency (WADA), which was established in 1999 as a foundation under the International Olympic Committee, works to promote, coordinate, and monitor the fight against doping in sports.

There are four major categories of performance enhancing drugs, and the WADA is investing in research in all of the areas:

Drugs that increase oxygen delivery: This is usually done by increasing the ability of blood to carry oxygen around the body by producing more red blood. Drugs that increase growth: These drugs increase the rate of growth and repair in body tissues. Gene/cell therapy: New on the scene, gene doping involves permanently altering the genetic code of your cells to increase strength and performance. Miscellaneous additions to Prohibited Substance List: Often products marketed as health supplements or protein supplements are grouped into this category.

“Designer drugs” are created when advanced labs design chemicals that will boost an athlete’s performance without being detected in urine and blood samples during routine drug testing. These modified drugs mimic the function of a known compound, but has a structure that is different enough to escape detection in doping tests…very sneaky!

Although drug testing is still a work in progress, the WADA testing done for the Olympics is the gold standard for sports doping.

How do scientists test for drug use in athletes? First, athletes are asked to give a sample, urine or blood for example, either during a sporting event, or some other time over the course of the training season. While it is easier for doping athletes to adulterate urine samples, they are preferred over blood tests because the rate of drug degeneration (half-life) in blood is much higher.

Second, urine samples are screened by a competitive immunoassay test. This test uses antibodies that specifically recognize a certain banned drug. Basically, a modified version of the drug that has been labeled with a radioactive substance, fluorescent tag, or coloured molecule “competes” with the targeted drug in the urine sample for binding sites on the antibody. When binding sites are saturated, researchers measure either the amount of free labeled-drug or labeled-drug bound to the antibody to calculate the amount of prohibited drug in the sample (see figure).

As the antibodies available today often cannot recognize small differences in the chemical structure between targeted drugs and similar “designer” compounds, a positive immunoassay test result is confirmed by a second set of experiments that isolate and identify the drug.

This second set of experiments uses a procedure called chromatography. Here, drugs are separated from a sample according to their physical properties – solubility, volatility and polarity. In gas chromatography, the sample is exposed to two different phases for which each compound has a different affinity. Drugs favoring the stationary phase (liquid) will lag behind and, therefore, separate from compounds that favor the mobile phase (gas).

After separation, the individual drugs are identified by a different procedure called mass spectrometry, a technique that breaks down, or fragments, a drug by bombarding it with electrons. Each drug will break down differently to produce a “fragmentation pattern”, sort of like a fingerprint, and can be used to specifically identify which drug is in the sample.

The problem is that when drug users hear that the WADA labs are close to identifying the new performance-enhancing compound, the drugs are taken out of circulation, or “burned”, and a new compound is developed instead, making it difficult for WADA to catch up with the drug cheats.

No doubt that news of the eight cross-country skiers will have everyone thinking about integrity of competition in the Olympic Games. Whether they test positive or negative, it is evident that these international games will rely on science to seek out the truth.

For more information, check out these links:

CBC Olympic Games Site: www.cbc.ca/olympics/

World Anti-Doping Agency: www.wada-ama.org/en/

Allison is a graduate of Human Kinetics from the University of Guelph and is currently finishing her Master's degree in Anatomy and Neurobiology at Dalhousie University, in Halifax. She is involved in many Halifax-based youth programs such as Let's Talk Science, and Brain Awareness Week (run out of the local Museum of Natural Resources).


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