"I can make you feel better, but you render yourself at risk in five or six years of degenerative arthritis," says Randall Holcomb, the orthopedic surgeon in Memphis who will be participating in the human trials. "We never had a filler to put into that (mensical) defect to make it function again. This is kind of a miracle tissue."

Trying to help people with arthritis has been one of Cook's lifetime goals. He was raised largely by his mother and by his grandfather, a man who long suffered from arthritic knees and eventually became one of the first people in the nation to undergo total knee replacement surgery. "Ever since I was a kid, I wanted to help him," Cook says.

Cook grew up among animals, so it was natural that he would choose a career as a veterinarian. As a young child, he lived on a horse farm in Springfield, Ohio. After his parents divorced, he still maintained a small menagerie of dogs, cats, lizards and even an alligator at his new home in Tallahassee, Fla. But Cook's life took several detours before he settled into veterinary orthopedics at MU. As an undergraduate at Florida State University, Cook majored in mathematics education, a relatively easy major that allowed him to concentrate on his most important interest at the time: water-skiing.

By the time he was three, Cook was skiing at the family's lakeside summer home. He progressed through the amateur ranks and won a water-skiing scholarship to Florida State. In 1986, two years before he graduated, Cook turned pro, and for four years was a self-described "ski bum," traveling to tournaments around the country, making it into the money often enough to keep going. At one point, he ranked No. 12 in the world.

"When you're 19 or 20 you can live on a shoestring. Just the glory of it is enough," he says. "Those few years, I wouldn't trade it for anything."

But throughout those happy-go-lucky times, Cook maintained his desire to pursue research in arthritis. In 1989 he went back to college at the University of Missouri-St. Louis to pick up the prerequisites he'd need to go to medical or veterinary school. He was accepted by both, and chose veterinary school at MU.

He picked working with animals, Cook says, because "I love the hardest challenge. I'm driven to do the hardest thing. It's more of a challenge to work with a patient who can't talk to you."

After graduating from MU in 1994, Cook enrolled at the University of Minnesota for his internship. He returned to MU, where he completed a residency in small-animal orthopedics and a doctorate in pathobiology in 1998. He then joined the faculty.

The following year, Cook helped establish the University's Comparative Orthopaedic Laboratory, a multidisciplinary center studying arthritis and other joint disorders.

"What I like about my job is I can use what I learn about animals to apply to people and use what's available in humans for animals," Cook says. "The thing I like to ask at staff meetings with MDs is, 'What problems did you have with your patients that you couldn't fix today?' That really stimulates me to look for an answer."