Developments to Watch
Edited by Irene M. Kunii
Extra Mileage for Your Cell-Phone Battery
Tired of recharging--OR forgetting to recharge--your cell phone or PDA every couple of days? Polyfuel, a spin-off of SRI International in Palo Alto, Calif., has developed a micro fuel cell that promises to eliminate recharging hassles. The core technology is based on PEM, for proton exchange membrane, which has been used in prototypes of fuel cells designed for automobiles still on the drawing board.
Polyfuel's miniature device uses a simple chemical process that combines methanol and oxygen to produce electricity. When the cell runs out of fuel, you simply insert a small cartridge of methanol, just as you would an ink cartridge. Presto--you've got enough power to run a phone for about two weeks. While others have announced designs for cell-phone fuel cells, Polyfuel hopes to be the first to market with such a device, with a launch target of 2003.
Spinning Silk from Spuds
The threads of a spider web are stronger and more elastic than those of a silkworm. In fact, molecule for molecule, they're tougher than Kevlar or steel. That conjures up all kinds of industrial uses, from bulletproof vests and durable aircraft parts to wispy surgical sutures. But unlike silkworms, spiders cannot be domesticated: Put them in boxes, and they'll devour one another. So to mass-produce large volumes of spider-silk proteins, researchers are turning to gene-splicing.
For the past two years, scientists at Germany's Institute for Plant Genetics & Crop Plant Research in Gatersleben have been inserting spider genes into potato and tobacco plants. And they have succeeded in producing and harvesting the silk protein. As a result, predicts project leader Jurgen Scheller, "we could make industrial spider silk economically feasible." But that, he cautions, could take five to seven more years.
By William Echikson
A Lifeline for Leukemia: The Umbilical Cord
Leukemia victims who need bone-marrow transplants and can't locate matching donors may have a source of hope. In a study led by oncologist Mary J. Laughlin of University Hospitals of Cleveland, 26% of patients with terminal leukemia or other blood diseases recovered after receiving umbilical cord blood that wasn't from relatives. The results, published in the June 14 issue of The New England Journal of Medicine, are important because at present, only two out of 10 patients in the U.S. have a sibling who matches them perfectly. Caucasians have a 50% chance of finding a donor through the National Marrow Donor Program, but the odds decline to less than 15% for other ethnic groups.
Laughlin and her team are the first to demonstrate in transplant trials that versatile and relatively undeveloped stem cells from cord blood seek out the marrow and gradually build up a whole new immune system. In the study, 68 patients aged 18 to 58--who all had failed to find marrow donors--underwent intensive chemotherapy or radiation to deplete their bone marrow, then received cord blood transplants. Of this group, 90% experienced growth of new, healthy blood cells, and 18 remain disease-free.
For years, stem cells from donors' umbilical cord blood have been successfully transplanted into children with leukemia or other blood disorders. But until now, doctors thought adults were likely to reject cells from a less-than-perfect match. "We've shown that [this procedure] can save the lives of nearly one-third of adult patients for whom other treatments are likely to fail," says Laughlin.
Getting the Liver to Let Down Its Guard Sometimes
Interactions among drugs can wreak havoc in the body. The antidepressant herb Saint-John's-wort, for example, can neutralize oral birth control pills. It can also block anticancer drugs, antivirals for AIDS sufferers, and immunosuppressants prescribed for organ transplant patients.
A key to such drug interactions is a receptor molecule in the cells of the liver called PXR. When it encounters the active ingredient in Saint-John's-wort, it prompts the liver to produce an enzyme that seeks out and destroys certain foreign chemicals in the blood. And those targets, unfortunately, include a wide range of useful drugs.
PXR is now yielding up its secrets. Using a technique called X-ray crystallography, scientists at the University of North Carolina and GlaxoSmithKline have produced an atom-by-atom model of PXR that appears in the June 22 issue of Science. Knowing the precise arrangement of the molecule's 2,141 atoms, companies may be able to design drugs that won't activate the molecule, says UNC researcher Matthew R. Redinbo.
Redinbo's team has filed a patent on the structure. But others are hot on the molecule's trail. Scientists at the Salk Institute did pioneering work on PXR and have filed patents on the PXR gene and on mice engineered to produce human PXR in their livers. Companies could test drugs on the mice and nix those that activate PXR.
By Adam Aston
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Copyright 2001 , by The McGraw-Hill Companies Inc. All rights reserved.
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