Developments to Watch
EDITED BY CATHERINE ARNST
This Plumber's Helper Could Get a Promotion
There's a dirty little secret at the other end of your sewer line. Almost half the cost of wastewater filtration arises from clearing clogged and fouled filtration membranes. Now, polymer scientists at Massachusetts Institute of Technology say they have found a simple way to clean up the mess.
The basic problem with filtration membranes is that the only materials strong enough for the purpose are water-repellent polymers. But these polymers tend to clog quickly because they attract and anchor protein and oil molecules that are suspended in water, and they have relatively few surface pores. So-called hydrophilic, or water-loving, polymers are much less prone to fouling, but existing methods for putting hydrophilic coatings on the exterior surfaces of filters are costly. They also don't solve the problem, because the internal channels of the filter remain water-repellent.
MIT professor Anne Mayes added a dash of hydrophilic polymer to the standard industry process for making membranes. The result: Bristly hydrophilic linings formed on all surfaces, internal and external. Serendipitously, the hybrid membranes are not only cheap to make but they also have many more surface pores than those made from conventional polymers, increasing efficiency by a factor of 10 or more.
In addition to water treatment, MIT researchers are exploring applications in drug delivery and artificial organs. The technology is drawing interest at a wide range of organizations, from membrane manufacturers to biological research groups.
By Mitch Nelin
Cells That Fight MS?
Frozen human cells have been successfully used to restore nerve conduction in mice with multiple sclerosis, report scientists from Yale University. The research raises the possibility that someday patients with the degenerative nervous system disease could be treated with cells harvested from their own bodies.
Multiple sclerosis is a lifelong disease that destroys the insulating material, called myelin, that surrounds nerves in the brain and spinal cord. Sufferers develop a number of neurological problems, including blurred vision, loss of motor skills, numbness, and extreme fatigue. The cause is unknown, and there is no cure.
The Yale researchers reported in the Feb. 1 issue of the Journal of Neuroscience that they extracted Schwann cells, which make myelin, from human nerves taken from amputated limbs. The cells were frozen and stored, and then injected into myelin-stripped regions in the spinal cords of rats that had been genetically modified to have human MS. Within three to five weeks, extensive myelin had formed in the lesions. Even more significantly, the re-myelinated nerves were able to transmit nerve impulses again. The scientists, led by Yale professor Jeffrey D. Kocsis, cautioned that it is unclear whether the same technique would work in humans. However, he says, the procedure could be tried in human clinical trials.
Of Mice and Men...And Fat
If your idea of heaven is eating whatever strikes your fancy without gaining weight, you might envy these mice. Researchers at the Whitehead Institute in Cambridge, Mass., have discovered a human protein that enabled obese mice to lose weight while eating as much fat and sugar as they wanted. The protein, called gAcrp30, caused "profound and sustained weight loss" in chubby mice when administered in daily doses, Whitehead biologist Harvey Lodish says. By continuing the daily doses, the mice kept the weight off over a sustained period--despite their fatty diets.
The protein is a fragment of Acrp30, a hormone secreted by fat cells that Lodish's lab identified five years ago. The fragment circulates in the blood and causes muscle to burn fatty acids at a faster-than-normal rate. Fat is thus turned into energy before it can be stored in the cells. This is in marked contrast to most weight-loss drugs, which work by purging fatty acids before they can be absorbed and can cause gastrointestinal problems. The Whitehead mice suffered no side effects.
Lodish cautions that much more research is needed to determine if the compound will work the same way in humans as it does in mice. But Acrp30 has been licensed to Genset Corp. in La Jolla, Calif., for further development--if you want to volunteer for testing.
Innovations
-- Here's the botanist's version of alchemy: A group of biologists has figured out how to genetically convert leaves into petals. Scientists have long believed that flowers are simply modified leaves, and they have known how to convert petals into leaves for more than a decade. Going the other direction, however, has proved to be much more difficult. A team led by Martin F. Yanofsky of the University of California at San Diego came across a clue a year ago with the discovery that a trio of genes, when mutated in concert, produce an abnormality known as a double flower that is often found in roses and camellias. Now they report that two of these genes, when activated along with three others responsible for floral development, turned leaves into petals in the mustard plant. Don't try this in your home garden, though--it took a year of crossbreeding to come up with plants that expressed all five genes simultaneously.
-- Researchers have long speculated that children exposed to cocaine in the womb could suffer central nervous system damage and later developmental problems. A new study by scientists at Albert Einstein Medical Center in Philadelphia blows holes in this theory. They tested two groups of inner-city children at ages 3 and 5--65 of them had been exposed to cocaine in the womb, and 68 had not. Both groups scored equally poorly on developmental tests, and their home environment seemed to be the main determinant. "We have not found in utero cocaine exposure to be as important an influence as growing up in poverty," they report.
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Copyright 2001 , by The McGraw-Hill Companies Inc. All rights reserved.
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