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A Magic Pullet For Deafness


Chickens might one day unlock a cure for the hearing-impaired. That's the hope of scientists at Stanford University, who are studying the fowl to try to learn how they regenerate the tiny hair cells in their inner ear. Those cells convert sound into electrical impulses, which travel to the brain and produce hearing. Because chickens and other feathered creatures can regrow these cells after injury, there is no such thing as a deaf bird.

The researchers have figured out how to take embryonic stem cells from mice, implant them into the ears of chick embryos, and coax them to differentiate into hair cells. They're working on perfecting a similar procedure for deaf humans.

Hard disks and memory sticks store huge amounts of information, but they can malfunction when exposed to heat and humidity. An article scheduled for the Apr. 9 issue of Biotechnology Progress suggests a more reliable way to preserve info: by inserting it in the DNA of a resilient strain of bacteria.

Scientists like the idea because DNA, which carries the instructions to replicate life, could store hundreds of times more data than current means—and of course bacteria pass the data from one generation to the next. The bacteria used in this experiment form a protective layer that helps them survive extreme conditions. And to reduce the risk that data could get corrupted by genetic mutation, scientists can encode copies at multiple locations on each DNA strand.

To test the technique, a team at Keio University in Tokyo encoded a message into the bacteria—"E=mc 1905!"—in honor of Albert Einstein's theory of special relativity. They later reversed the process by sequencing, or reading, the entire DNA strand. Perfecting it for commercial use could take a decade or more, the scientists estimate.

It's not just kids who don't much like to take their medicine. Surveys have found that lack of medication compliance among adults with chronic disease can run as high as 65%. That's a big reason why the drug industry is looking for better delivery methods than pills or injections. European researchers think they have found the ideal device: a fake tooth that can deliver the correct dose of medication for weeks.

The electronic device, called IntelliDrug, fits into two fake molars that can be implanted into a patient's jaw to the rear of—or in place of—existing molars. Saliva enters a reservoir in the tooth through a membrane and dissolves the solid drug, which then flows through a small duct into the mouth, where it is absorbed by membranes in the cheeks.

Sensors monitor the amount of medication that is released and deliver the information to a tiny device that opens or closes the duct as needed. The tooth will also alert the patient through a remote device when the medication runs out or when the battery needs replacing. It holds about two weeks' worth of medicine.

IntelliDrug was designed by a consortium that includes the Fraunhofer Institute for Biomedical Engineering in Germany. Researchers there will test it in patients later this year, using a drug to treat narcotic addicts going through withdrawal.

— Scientists at Rensselaer Polytechnic Institute are using electricity to control the flow of water through carbon nanotubes. By reversing the charge in the tiny tubes, they can start and stop water streams at will. This is the first step toward designing nanotubes that can filter impurities from water and even desalinate seawater. The technology might also be used for other ultraprecise tasks, such as pulling specific strands of DNA from biological samples.

— Researchers at Clemson University have announced that they can produce beating heart tissue using standard inkjet printers. In 2004 the team demonstrated the use of 3D printers to make cells, and others have been able to print hard biomaterials such as bone. Now Clemson scientists have refined the technology so it can place living cells more precisely in a tissue-like scaffold, which holds them in place. They fill one inkjet cartridge with a material similar to human tissue, and another with cells, then activate each in an alternating process, "printing" the cells in much the same way color photos are made.


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