Theme & Variations
In Science, as in Music
As a researcher, Dan Drachman's passion for doggedly pursuing a "single melody" line is perhaps best illustrated by his early work investigating a disease known as arthrogryposis multiplex congenita, which affects roughly one in 3,000 newborns. Babies with the disease are born with frozen joints; many have weak muscles. Some die; those who survive run the gamut from being mildly affected to fully incapacitated. A regimen of assisted movement greatly helps some patients.
As a young resident in Boston, Drachman became intrigued by arthrogryposis after he was asked to autopsy a baby born with the disease. "The child had abnormal joints; they were fixed and distorted and he also had clubfoot," he explains. After a thorough autopsy, Drachman concluded that the baby must have been paralyzed prior to birth, which led to a question: "Every rigid joint also had atrophied muscles around it. That was peculiar. Why would a fixed joint affect muscles?"
Upon questioning the baby's mother, he discovered that her two older children had done somersaults in utero, but this one hadn't moved. Also, during her pregnancy, her older children developed rashes and recovered. "I hung up the phone feeling sure she'd gotten a virus that destroyed fetal motor nerves," he recalls.
Moving to the National Institutes of Health, Drachman continued to pursue answers. The idea that nerves not working would somehow affect the nature of muscle was a new one. It might have all sorts of ramifications for paralytic disease. He set about developing a model of arthrogryposis in a chicken embryo. "It didn't matter what I used to block the nerves — curare, botulinum, microsurgery — the joints all came out like the baby's in Boston," he says. After a chance meeting with an Australian, P.D.F. Murray, then the world's expert on the joints of the head and neck of the chick embryo, Drachman sent him samples of tissue from his animal models. The plan was for Murray to section it, make slides, and the two would get together to figure out what had happened to the joints. Unfortunately, Murray suffered a fatal heart attack aboard the ship on his way to meet Drachman in London. A deeply saddened Drachman took home the slides and photos passed along by Murray's wife and pored over them "in excruciating detail."
Eventually Drachman concluded that, for proper formation, every kind of joint requires movement. "If movement stops, the joint fuses. And it does so in different ways, depending on the joint. Paralyze the trachea, and it becomes a solid tube instead of rings of cartilage. A chicken's upper beak is long because it's mobile in utero, and the lower beak is short because it's not."
That work, and follow-up studies, helped launch Drachman's
shift into myasthenia gravis, now likely the best
understood of all the neuromuscular diseases, thanks to his
studies and collaborations with Hopkins colleagues. More
than that, it has also become a basis for much of the
rehabilitation that now helps nerve-injured patients.
Moreover, studies that underpin understanding of muscular
dystrophy as well as today's promise-laden trials of growth
factors for neuromuscular disease are happy offshoots.
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