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A Key Clue That Might Put the Brakes on HIV


Although it has long been possible to detect the presence of HIV, the virus that causes AIDS, scientists have struggled to distinguish infected cells from healthy ones. Researchers at the University of Colorado now say they have explained the presence of what may be an important characteristic: When a cell produces HIV, a protein called CTLA4 appears on its surface.

Researchers first observed CTLA4 on HIV-infected cells in the late 1990s, but no one could figure out how the protein related to the virus' replication process. Such cells tend to hoard copies of the virus inside instead of releasing them steadily after infection. This study shows that CTLA4 only migrates to the cell's outer surface when the hoarded virus is ready to be released.

The discovery "opens up all sorts of doors for figuring out new ways to stop cells from making new virus," says Alex Franzusoff, an associate professor of cellular and structural biology at the university's Health Sciences Center. The protein marker could also help doctors fine-tune the treatment of their patients' anti-HIV drug regimens. In early June, a routine environmental inspection turned up traces of nerve gas at a military base in Uzbekistan that thousands of U.S. soldiers had passed through. Personnel were immediately evacuated, but it took days to positively identify the deadly traces. That's because today's chemical-weapons detection kits are quick to sense danger but do a poor job of sorting one warfare agent from another. To these kits, which are based on the reaction of natural enzymes to poisons, nerve gas can look just like a less harmful but chemically similar pesticide.

With a grant from the military, biotech startup Semorex Inc. is developing polymers that could inexpensively mimic certain properties of the enzymes in current chemical-detection kits and outperform in them in some tasks. Known as molecularly imprinted polymers, or MIPs, these tiny plastic particles are dotted with cavities engineered to trap specific molecules, including organophosphate toxins such as sarin and other nerve gases. Natural enzymes respond more quickly, says Semorex Chief Scientific Officer Bernard Green, but MIPs could actually I.D. the culprit. And detection is just the start. Because the polymers encapsulate the poisons, MIPs could be used in mop-up operations--either sprayed as aerosols, or embedded in fabrics. In the civilian arena, Semorex is designing MIPs that could be ingested, to rid the body of toxins linked to cancer and other diseases. One morning, Francis X. Hursey cut himself shaving. So the engineer grabbed a piece of volcanic rock he had been studying to see if it would stanch the bleeding. It did, and now--10 years and three patents later--the erstwhile inventor is commercializing QuikClot. When sprinkled into a wound, the proprietary granular mineral sops up the liquid in blood but leaves behind the clotting factors. "It gives a giant headstart to the body's own ability to clot," says Bart Gullong, vice-president of Z-Medica, Hursey's Newington (Conn.) startup.

The armed forces have taken a special interest in QuikClot because it's so well-suited to harsh battlefield conditions. Manufactured at 427C, it's virtually indestructible, as well as biologically and chemically inert. QuikClot can remain in a wound until treatment begins. And at around $21 per 100-g packet, it goes for a fraction of what current-generation coagulants cost. The life-saving gravel can already be found in soldiers' medi-kits in Afghanistan. And a civilian version isn't far behind: the FDA approved QuikClot in May. -- Dialing while driving may be more dangerous than previously thought. A study from the University of Rhode Island says drivers on cell phones may suffer from tunnel vision. Worse, test subjects experienced lessened mental alertness and reduced visual acuity well after their conversations finished. The study, conducted on volunteers using head-mounted eye-movement sensors, could prompt more calls for laws restricting in-car phone use.

-- It seems obvious that everyone's handwriting is unique. But courts have never been entirely comfortable with the idea. Now, using computer analysis of hundreds of features of writing samples--from document layout to line spacing and stroke marks--State University of New York at Buffalo scientists have produced the first peer-reviewed scientific validation that each person's scrawl is special. The finding may boost the use of handwritten evidence in trials.

-- Wild tomatoes produce a substance with the potential to replace DEET, the active ingredient in many mosquito repellents. DEET can cause skin irritation and, in high concentrations, may be unsafe for children, according to the Environmental Protection Agency. The natural substance, called IBI-246, is part of the tomato plant's defense against common field pests, according to Michael Roe, a North Carolina State University entomologist who recognized its bug-begone properties. It fends off ticks, fleas, cockroaches, ants, and flies, too. IBI-246 also shows promise for farm-field use. Roe expects EPA approval this fall.


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