Archive for the ‘Women’s Athletics’ Category

A University of Colorado at Boulder study of a space-age, low-gravity training machine used by several 2008 Olympic runners showed it reduced impacts on muscles and joints by nearly half when subjects ran at the equivalent of 50 percent of their body weight.

The new study has implications for both competitive runners rehabilitating from injuries and for ordinary people returning from knee and hip surgeries, according to Associate Professor Rodger Kram of CU-Boulder’s integrative physiology department.

Known as the “G-Trainer,” the machine consists of a treadmill surrounded by an inflatable plastic chamber that encases the lower body of the runner, said Kram. Air pumped into the chamber increases the pressure and effectively reduces the weight of runners, who are sealed in the machine at the waist in a donut-shaped device with a special zipper and “literally lifted up by their padded neoprene shorts,” he said.

Published in the August issue of the Journal of Applied Biomechanics, the study is the first to quantify the effects of running in the G-Trainer, built by Alter-G Inc. of Menlo Park, Calif., using technology developed at NASA’s Ames Research Center in California. The paper was authored by Kram and former CU-Boulder doctoral student Alena Grabowski, now a postdoctoral researcher at the Massachusetts Institute of Technology.

Although G-Trainers have been used in some sports clinics and college and professional sports training rooms since 2006, the new study is the first scientific analysis of the device as a training tool for running, said Grabowski.

“The idea was to measure which levels of weight support and speeds give us the best combination of aerobic workout while reducing the impact on joints,” said Kram. “We showed that a person can run faster in the G-Trainer at a lower weight and still get substantial aerobic benefits while maintaining good neuromuscular coordination.”

The results indicated a subject running at the equivalent of half their weight in the G-Trainer at about 10 feet per second, for example — the equivalent of a seven-minute mile — decreased the “peak” force resulting from heel impact by 44 percent, said Grabowski. That is important, she said, because each foot impact at high speed can jar the body with a force equal to twice a runner’s weight.

Several former CU track athletes participating in the 2008 Olympics in Beijing have used the machine, said Kram. Alumna Kara Goucher, who will be running the 5,000- and 10,000-meter races in Beijing, has used the one in Kram’s CU-Boulder lab and one in Eugene, Ore., for rehabilitation, and former CU All-American and Olympic marathoner Dathan Ritzenhein also uses a G-Trainer in his home in Oregon. Other current CU track athletes who have been injured have tried the machine in Kram’s lab and found it helpful to maintain their fitness as they recovered, Kram said.

For the study, the researchers retrofitted the G-Trainer with a force-measuring treadmill invented by Kram’s team that charts vertical and horizontal stress load on each foot during locomotion, measuring the variation of biomechanical forces on the legs during running. Ten subjects each ran at three different speeds at various reduced weights, with each run lasting seven minutes. The researchers also measured oxygen consumption during each test, Kram said.

Grabowski likened the effect of the G-Trainer on a runner to pressurized air pushing on the cork of a bottle. “If you can decrease the intensity of these peak forces during running, then you probably will decrease the risk of injury to the runner.”

The G-Trainer is a spinoff of technology originally developed by Rob Whalen, who conceived the idea while working at NASA Ames as a National Research Council fellow to help astronauts maintain fitness during prolonged space flight. While the NASA technology was designed to effectively increase the weight of the astronauts to stem muscle atrophy and bone loss in low-gravity conditions, the G-Trainer reverses the process, said Grabowski.

In the past, sports trainers and researchers have used climbing harnesses over treadmills or flotation devices in deep-water swimming pools to help support the weight of subjects, said Kram. Harnesses are cumbersome, while pool exercises don’t provide sufficient aerobic stimulation and biomechanical loading on the legs, he said.

Marathon world-record holder Paula Radcliffe of Great Britain is currently using a G-Trainer in her high-altitude training base in Font-Remeu, France. Radcliffe is trying to stay in top running shape while recovering from a stress fracture in her femur in time for the 2008 Olympic women’s marathon on Aug. 17, according to the London Telegraph.

Kram and Grabowski have begun a follow-up study of walking using the G-Trainer. By studying subjects walking at various weights and speeds in the machine, the researchers should be able to quantify its effectiveness as a rehabilitation device for people recovering from surgeries, stress fractures and other lower body injuries, Kram said.

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Article adapted by MD Sports from original press release.
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Contact: Rodger Kram
University of Colorado at Boulder

Neuroscience researchers at the Duke-NUS Graduate Medical School in Singapore have shown for the first time what happens to the visual perceptions of healthy but sleep-deprived volunteers who fight to stay awake, like people who try to drive through the night.

The scientists found that even after sleep deprivation, people had periods of near-normal brain function in which they could finish tasks quickly. However, this normalcy mixed with periods of slow response and severe drops in visual processing and attention, according to their paper, published in the Journal of Neuroscience on May 21.

“Interestingly, the team found that a sleep-deprived brain can normally process simple visuals, like flashing checkerboards. But the ‘higher visual areas’ – those that are responsible for making sense of what we see – didn’t function well,” said Dr. Michael Chee, lead author and professor at the Neurobehavioral Disorders Program at Duke-NUS. “Herein lies the peril of sleep deprivation.”

The research team, including colleagues at the University of Michigan and University of Pennsylvania, used magnetic resonance imaging to measure blood flow in the brain during speedy normal responses and slow “lapse” responses. The study was funded by grants from the DSO National Laboratories in Singapore, the National Institutes of Health, the National Institute on Drug Abuse, the NASA Commercialization Center, and the Air Force Office of Scientific Research.

Study subjects were asked to identify letters flashing briefly in front of them. They saw either a large H or S, and each was made up of smaller Hs or Ss. Sometimes the large letter matched the smaller letters; sometimes they didn’t. Scientists asked the volunteers to identify either the smaller or the larger letters by pushing one of two buttons.

During slow responses, sleep-deprived volunteers had dramatic decreases in their higher visual cortex activity. At the same time, as expected, their frontal and parietal ‘control regions’ were less able to make their usual corrections.

Scientists also could see brief failures in the control regions during the rare lapses that volunteers had after a normal night’s sleep. However, the failures in visual processing were specific only to lapses that occurred during sleep deprivation.

The scientists theorize that this sputtering along of cognition during sleep deprivation shows the competing effects of trying to stay awake while the brain is shutting things down for sleep. The brain ordinarily becomes less responsive to sensory stimuli during sleep, Chee said.

This study has implications for a whole range of people who have to struggle through night work, from truckers to on-call doctors. “The periods of apparently normal functioning could give a false sense of competency and security when in fact, the brain’s inconsistency could have dire consequences,” Chee said.

“The study task appeared simple, but as we showed in previous work, you can’t effectively memorize or process what you see if your brain isn’t capturing that information,” Chee said. “The next step in our work is to see what we might do to improve things, besides just offering coffee, now that we have a better idea where the weak links in the system are.”

 

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Article adapted by MD Sports from original press release.
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Contact: Mary Jane Gore
Duke University Medical Center

Other authors of the study include Jiat Chow Tan, Hui Zheng, and Sarayu Parimal of the Cognitive Neuroscience Lab at the Duke-NUS Graduate Medical School; Daniel Weissman of the University of Michigan Psychology Department; David Dinges of the University of Pennsylvania School of Medicine; and Vitali Zagorodnov of the Computer Engineering Department of the Nanyang Technological University in Singapore.

A strained muscle, sprained ankle or foot injury can make even the most motivated exerciser feel discouraged when it comes to working out.

But being injured doesn’t necessarily mean you can’t exercise, says Colleen Greene, wellness coordinator with MFit, the University of Michigan Health System’s health promotion division. By speaking with an expert and finding a plan that will work as you heal, you can still hit the gym while recovering.

“Exercise can definitely be beneficial for a person dealing with an injury. Depending on its type, the injured area should be moved and not left in place for a long period of time,” explains Greene. “Some people think they should just rest and not move at all with an injury. Doing that can actually be worse because—depending on the amount of time one does not move the appendage— the muscle might begin to atrophy.”

Greene notes that the general rule of thumb when initially handling an injury is to follow RICE—Rest, Ice, Compression and Elevation. Once you have done this, consult a doctor to look at the injury as soon as possible. You may be referred to a physical therapist or specialist trainer if the injury is severe enough. These professionals can provide guidance for your recovery, as well as give you tips on how to maintain strength while recovering.  

Greene also notes that there are “dos and don’ts” when it comes to specific injuries. Because each condition is unique, there are certain things a person can do and other activities the injured person should avoid while healing. She offers these tips on three common injuries:

General advice for any injury: See a physician or physical therapist to learn what exercises are possible with your type of injury. Focus on the goal of maintaining strength, not gaining it, while you are recovering. And always be wary of pain as you explore different workouts.

“Pain is always the indicator; discomfort is OK, but pain tells you when you should stop what you are doing and do something else,” Greene says. “You always want to keep in mind that you should be doing something that doesn’t re-injure or further injure yourself.”

Sprained ankle. When seeking out cardiovascular exercises, Greene suggests sticking with low- impact workouts, such as swimming or riding a stationary bike. She notes that running or aerobics are generally activities that are too high in impact. A person with a sprained ankle can also do upper-body or core impact exercises for strength training.

Plantar faciitis. Plantar faciitis is an overuse injury normally caused by a lack of cross training. For example, a person may develop plantar faciitis by only running when training for a marathon, but not preparing through other exercises, such as swimming or biking. Greene notes that people dealing with this type of injury need to focus on resting in order to heal, but it is possible to explore low-impact core and upper-body exercises while recovering.

“There are not a lot of ways other than physical therapy to recover from plantar faciitis except for resting,” she says. “You want to do things that are low impact without a lot of pressure on the area.”

Grab an ice pack, get some rest and allow your injury to fully recover before trying to get stronger.

Strained and pulled muscle. “The first thing a person with a pulled or strained muscle should know is that they, like everyone, should warm up thoroughly before doing anything,” Greene notes.

She also says that people with this type of injury should stay in a pain-free range by focusing on conditioning the side of the body opposite of the strained or torn muscle. If you have pulled a hamstring, for example, then aim to work on your upper-body.

Greene also notes that there are preventative measures that a person can take to avoid pulling or training a muscle. First, Greene recommends a good warm-up for five to 10 minutes. Second, be sure to cool down at the end of your workout. And don’t forget to stretch.

“We find that as people age, they can actually pull muscles by doing everyday things such as bending over to grab a bag of groceries or leaning over to put something on a shelf,” she explains. “So the preventative measures that can be taken to avoid pulling or tearing a muscle with exercise are also measures that should be taken to avoid tearing or pulling a muscle in everyday life, not just on a basketball court.”

Overall, Greene believes the most important thing injured exercisers can do when hitting the gym is to pay attention to their body. She also advises to stop immediately if a workout becomes painful.  

“One of the basic exercise myths is ‘no pain, no gain.’ We used to think that a long time ago,” says Greene. “If you are actually in pain, you should stop immediately. Now we say, ‘no discomfort, no gain.’ There is a big difference.”

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Article adapted by MD Sports from original press release.
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MFit, the Health Promotion Division of the University of Michigan Health System (UMHS) provides medically-based personalized health and wellness programs and services to UMHS patients, UM employees, the greater Washtenaw County community, and employers in Michigan.

Source: Laura Drouillard
University of Michigan

Researchers from the Division of Health Promotion & Sports Medicine at Oregon Health & Science University have found steroid use among teen girls is not limited to athletes and often goes hand in hand with other unhealthy choices, including smoking and taking diet pills. The study was published in the Archives of Pediatrics & Adolescent Medicine, a JAMA/Archives journal.Diane Elliot, M.D., professor of medicine (health promotion and sports medicine), OHSU School of Medicine, and colleagues analyzed findings from the Center for Disease Control’s Youth Risk Behavior Survey of 7,544 ninth- through 12th-grade girls from around the country. The questionnaire asked about sports participation, anabolic steroid and drug use, and other illegal or unhealthy behaviors. Approximately 5 percent of participants reported prior or ongoing anabolic steroid use.

In addition to greater substance use, young female steroid users were more likely to have had sexual intercourse before age 13; have been pregnant; drink and drive or have ridden with a drinking driver; carry a weapon; have been in a fight on school property; have feelings of sadness or hopelessness almost every day for at least two weeks; and have attempted suicide. Those reporting anabolic steroid use were less likely to participate in team athletics.

Overall, more than two-thirds of those surveyed reported trying to change their weight. Girls who used steroids were more likely try extreme weight-loss techniques, such as vomiting and laxative use.

Adolescent girls reporting anabolic steroid use had significantly more other health-harming behaviors, Elliot explained, “They were much more likely to use other unhealthy substances, including cigarettes, alcohol, marijuana and cocaine.”

“Across all grades, these seem to be troubled adolescents with co-occurring health-compromising activities in the domains of substance use, sexual behavior, violence and mental health,” Elliot said. “Anabolic steroid use is a marker for high-risk girls. High-risk young women have received less attention than young men, perhaps reflecting that their actions are less socially, albeit more personally, destructive. Further study is needed to develop effective interventions for these young women.”

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Article adapted by MD Sports Weblog from original press release.
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Contact: Tamara Hargens
Oregon Health & Science University

Baseball team owners, players and fans seem to agree on the importance of drug testing for steroids, according to current reports, but the entire scope of performance-enhancing substances available for all athletes is vastly broader and many of the drugs employed by athletes are not easily detectable, says a Penn State researcher.”The use, misuse and abuse of drugs have long shaken the foundations of amateur and professional sports–baseball, football, track and field, gymnastics and cycling, to name just a few,” says Dr. Charles Yesalis, Penn State professor of exercise and sport science and health policy and administration. “The problem is not new. But like the rest of technology, doping in sport has grown in scientific and ethical complexity. In addition to drugs, we have natural hormones, blood doping, diuretics, nutritional supplements, social and recreational drugs, stimulants and miscellaneous substances, some of which may not even be on any list of banned substances.”

While drug testing technology struggles to keep up, an array of new and emerging technologies has arrived or is on the horizon with potential for abuse by athletes including gene transfer therapy, stem cell transplantation, muscle fiber phenotype transformation, red blood cell substitutes and new drug delivery systems, says Yesalis

“It is not too hard to imagine the day when muscles can be selectively enlarged or contoured,” according to the book. “Just imagine the consequences of a kinesiologist isolating specific muscles and selectively injecting designer genes into those muscles to maximize their function.”

The new book brings together the latest and most comprehensive scientific information about performance-enhancing substances, as well as discussion of drug testing, legal and social issues, and future directions by sports governing organizations.

“Sport has a responsibility to maintain a level playing field for the trial of skill,” Yesalis says. “The use of chemical and pharmacologist agents is cheating – just like using a corked baseball bat. But unlike the bat, doping is shrouded in mystery. Athletes and their advisors are constantly seeking ‘gray areas” surrounding the rules, and if something is not explicitly banned, then why not try it. This slippery slope of rationalization is treacherous and appealing to a player or team seeking glory and money rewards.”

In one chapter, “Drug Testing and Sport and Exercise,” author R. Craig Kammerer suggests that improvement in current tests and developments in new methods will assist future policymaking by athletic federations. However, effective testing must become more widespread and include unannounced testing outside of competition. Sanctions against athletes must be more fairly and uniformly applied, with thorough investigation to avoid false positive results and ruin an athlete’s career.

The difficulty of detecting and preventing the abuse of performance enhancing substances by adult athletes may seem futile but remains necessary as part of the effort to discourage abuse by youths who emulate professional athletes and also seek a winning advantage, Yesalis notes.

A recent government study of adolescent drug use shows an alarming increase in anabolic steroid use among middle school youths from 1998-1999 with an estimated 2.7 percent of eighth graders saying they have used the drugs. A larger survey by Blue Cross and Blue Shield estimates that one million U.S. children between the ages of 12 and 17 may have taken performance-enhancing substances including creatine, according to the book.

“Children and teens can seriously harm their future health by misusing these substances,” Yesalis says. “For example, steroids alone can cause scarring acne, hair loss and testicular atrophy, and may increase the risk of stroke and heart disease. It is just as important to note that little is known about the health consequences of many of the other substances used to enhance performance. Yet some coaches and parents look the other way and even actively encourage the use of performance-enhancing substances in pursuit of scholarships and winning.

“There is too much fame and fortune to be gained by being a winner in sports,” he notes. “It’s interesting to see that baseball fans being polled support drug testing and a ban on steroids, but it will take fans of all major sports to take a stand by turning off their TV sets or not buying a ticket to sports events before adult athletes, coaches and team owners stop trying to cheat. And, that’s probably not going to happen.”

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Article adapted by MD Sports Weblog from original press release.
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Contact: Vicki Fong
Penn State

And it increases endurance to run a mile and decreases inflammation

The Salk Institute scientist who earlier discovered that enhancing the function of a single protein produced a mouse with an innate resistance to weight gain and the ability to run a mile without stopping has found new evidence that this protein and a related protein play central roles in the body’s complex journey to obesity and offer a new and specific metabolic approach to the treatment of obesity related disease such as Syndrome X (insulin resistance, hyperlipidemia and atherosclerosis).

Dr. Ronald M. Evans, a Howard Hughes Medical Investigator at The Salk Institute’s Gene Expression Laboratory, presented two new studies (date) at Experimental Biology 2005 in the scientific sessions of the American Society for Biochemistry and Molecular Biology. The studies focus on genes for two of the nuclear hormone receptors that control broad aspects of body physiology, including serving as molecular sensors for numerous fat soluble hormones, Vitamins A and D, and dietary lipids.

The first study focuses on the gene for PPARd, a master regulator that controls the ability of cells to burn fat. When the “delta switch” is turned on in adipose tissue, local metabolism is activated resulting in increased calorie burning. Increasing PPARd activity in muscle produces the “marathon mouse,” characterized by super-ability for long distance running. Marathon mice contain altered muscle composition, which doubles its physical endurance, enabling it to run an hour longer than a normal mouse. Marathon mice contain increased levels of slow twitch (type I) muscle fiber, which confers innate resistance to weight gain, even in the absence of exercise.

Additional work to be reported at Experimental Biology looks at another characteristic of PPARd: its role as a major regulator of inflammation. Coronary artery lesions or atherosclerosis are thought to be sites of inflammation. Dr. Evans found that activation of PPARd suppresses the inflammatory response in the artery, dramatically slowing down lesion progression. Combining the results of this new study with the original “marathon mouse” findings suggests that PPARd drugs could be effective in controlling atherosclerosis by limiting inflammation and at the same time promoting improved physical performance.

Dr. Evans says he is very excited about the therapeutic possibilities related to activation of the PPARd gene. He believes athletes, especially marathon runners, naturally change their muscle fibers in the same way as seen in the genetically engineered mice, increasing levels of fat-burning muscle fibers and thus building a type of metabolic ‘shield” that keeps them from gaining weight even when they are not exercising.

But athletes do it through long periods of intensive training, an approach unavailable to patients whose weight or medical problems prevent them from exercise. Dr. Evans believes activating the PPARd pathway with drugs (one such experimental drug already is in development to treat people with lipid metabolism) or genetic engineering would help enhance muscle strength, combat obesity, and protect against diabetes in these patients.

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Article adapted by MD Sports Weblog from original press release.
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Contact: Sarah Goodwin
Federation of American Societies for Experimental Biology

The Johns Hopkins scientists who first created “mighty mice” have developed, with pharmaceutical company Wyeth and the biotechnology firm MetaMorphix, an agent that’s more effective at increasing muscle mass in mice than a related potential treatment for muscular dystrophy now in clinical trials.

The new agent is a version of a cellular docking point for the muscle-limiting protein myostatin. In mice, just two weekly injections of the new agent triggered a 60 percent increase in muscle size, the researchers report in the Proceedings of the National Academy of Sciences, published and available publicly through the journal’s website.

The researchers’ original mighty mice, created by knocking out the gene that codes for myostatin, grew muscles twice as big as normal mice. An antibody against myostatin now in clinical trials caused mice to develop muscles 25 percent larger than those of untreated mice after five weeks or more of treatment.

The researchers’ expectation is that blocking myostatin might help maintain critical muscle strength in people whose muscles are wasting due to diseases like muscular dystrophy or side effects from cancer treatment or AIDS.

“This new inhibitor of myostatin, known as ACVR2B, is very potent and gives very dramatic effects in the mice,” says Se-Jin Lee, M.D., Ph.D., a professor of molecular biology and genetics in Johns Hopkins’ Institute for Basic Biomedical Sciences. “Its effects were larger and faster than we’ve seen with any other agent, and they were even larger than we expected.”

ACVR2B is the business end of a cellular docking point for the myostatin protein, and it probably works in part by mopping up myostatin so it can’t exert its muscle-inhibiting influence. But the researchers’ experiments also show that the new agent’s extra potency stems from its ability to block more than just myostatin, says Lee.

“We don’t know how many other muscle-limiting proteins there may be or which ones they are,” says Lee, “but these experiments clearly show that myostatin is not the whole story.”

The evidence for other players came from experiments with mighty mice themselves. Because these mice don’t have any myostatin, any effects of injecting the new agent would come from its effects on other proteins, explains Lee. After five injections over four weeks, mighty mice injected with the new agent had muscles 24 percent larger than their counterparts that didn’t get the new agent.

“In some ways this was supposed to be a control experiment,” says Lee. “We weren’t really expecting to see an effect, let alone an effect that sizeable.”

In other experiments with normal female mice, weekly injections of the new agent provided the biggest effect on muscle growth after just two weeks at the highest dose given (50 milligrams per kilogram mouse weight). Depending on the muscle group analyzed, the treated mice’s muscles were bigger than untreated mice by 39 percent (the gastrocnemius [calf] muscle) to 61 percent (the triceps).

After just one week, mice given a fifth of that highest dose had muscles 16 percent to 25 percent bigger than untreated mice, depending on the muscle group analyzed, and mice treated with one injection a week for two, three or four weeks continued to gain muscle mass.

But although the new agent seems quite promising, its advantage in potency also requires extra caution. “We don’t know what else the new agent is affecting or whether those effects will turn out to be entirely beneficial,” says Lee.

Lee says they also are conducting experiments with the mice now to see whether the effect lasts after injections cease and whether it helps a mouse model of muscular dystrophy retain enough muscle strength to prolong life.

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Article adapted by MD Sports Weblog from original press release.
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Contact: Joanna Downer
Johns Hopkins Medical Institutions

The research was funded by grants from the National Institute of Child Health and Human Development and the National Cancer Institute and by funds from Wyeth Research and MetaMorphix Inc. The new agent was produced and first tested at Wyeth, and the inhibitor used in the current mouse studies was produced at MetaMorphix. All of the mouse studies described in this article and in the PNAS paper were conducted in Lee’s laboratory at Johns Hopkins.

Authors on the report are Se-Jin Lee and Suzanne Sebald of Johns Hopkins; Lori Reed of Wyeth Exploratory Drug Safety, and Monique Davies, Stefan Girgenrath, Mary Goad, Kathy Tomkinson, Jill Wright and Neil Wolfman of Wyeth Discovery Research; Christopher Barker, Gregory Ehrmantraut, James Holmstrom and Betty Trowell of MetaMorphix Canada; Barry Gertz, Man-Shiow Jiang, Li-fang Liang, Edwin Quattlebaum and Ronald Stotish of MetaMorphix, Beltsville, Md.; Martin Matzuk of Baylor College of Medicine; and En Li of Harvard Medical School.

Myostatin was licensed by The Johns Hopkins University to MetaMorphix and sublicensed to Wyeth. Lee is entitled to a share of sales royalty received by The Johns Hopkins University from sales of this factor. The Johns Hopkins University and Lee also own MetaMorphix stock, which is subject to certain restrictions under university policy. Lee is a paid consultant to MetaMorphix. The terms of these arrangements are being managed by the university in accordance with its conflict of interest policies.

On the Web: http://www.pnas.org/cgi/content/abstract/0505996102v1