NOT JUST ANOTHER WEED KILLER

In a remarkable example of cross-fertilization between industry and medicine, a
substance developed to kill weeds is being used to treat a potentially fatal
liver disease. Triggered by overproduction of the amino acid tyrosine, the
malady, known as hereditary tyrosinemia, can produce liver failure in infants or
liver cancer in children. Without a liver transplant, victims invariably die
before reaching age 30.

Researchers at the ICI Central Toxicology Laboratory in Cheshire, England,
formulated a substance called NTBC as an agricultural herbicide. In the process,
they noticed that NTBC blocked the production of tyrosine. They alerted
tyrosinemia expert Sven Lindstedt and his colleagues at the University of
Gothenburg in Sweden, who soon administered NTBC to five patients aged two
months to six years.

Although one patient subsequently needed a liver transplant, after seven months
of treatment the other four showed improved liver function and increased
appetite and were more alert and active. Lindstedt has gone on to treat 48 more
patients in 12 countries and is now negotiating with a Swedish drug manufacturer
to develop NTBC as a commercial drug. The prognosis? ``We've treated too few
patients to say how they'll do in the long run,'' Lindstedt says. ``But so far,
we're quite hopeful.''