Developments to Watch
THIS BUS FIXES POTHOLES ON THE RUN
LONG TIRED OF SUSPENSION-BENDING potholes and endless traffic jams caused by road repairs? Leo M. Mara, a technician at Sandia National Laboratories, may have the solution.
Inching past a repair crew one day, Mara decided to design a vehicle to repair potholes on the run. It took him four years to figure out the details, but he has just won a patent on the complete system. The idea calls for a vehicle about the size of a Greyhound bus. On its front bumper are scanners that spot cracks and holes in the road. Once spied, the gaps are cleaned with high-pressure air and vacuumed by systems under the front of the vehicle. Then, as the repair truck drives over the holes, arrays of nozzles attached to the bottom of the chassis shoot filler material in the pattern needed to fill the flaws. Equipment further back on the vehicle tamps down and cleans the patches and makes sure the fixes are complete.
Mara figures the vehicle could operate at 10 mph or faster and could fill small cracks long before they turn into dangerous potholes. That would make the nation's roads a lot smoother and safer. Sandia is seeking a partner to commercialize the system.BY JOHN CAREYReturn to top
ON THE TRAIL OF THE JUMPING GENES
A CRUCIAL ASPECT of treating patients with gene therapy or engineering genetically altered animals is the method for delivering new genes. But none of the techniques attempted to date, from using modified viruses to injecting DNA alone, has proven ideal. That's the reason University of Minnesota geneticist Perry B. Hackett decided to harness nature's own system for shuffling around DNA--using so-called jumping genes, also known as transposons.
In lower creatures, such as fruit flies, these jumping genes rapidly move chunks of DNA from one chromosome to another. That helps explain how such animals can mutate so quickly. Hackett reasoned that transposons would make good vehicles for the delivery of genes to treat disease or to correct genetic defects. But active jumping genes weren't known to exist in humans or any other vertebrate.
Hackett decided to take a closer look. Although his research team hunted through the vertebrate kingdom to ferret out examples of working jumping genes, it failed to discover any. But the researchers did locate mutated transposons in Atlantic salmon and rainbow trout that had been active millions of years ago.
Hackett spliced together the transposons from each fish to create the first working vertebrate jumping gene. Last year, the researchers conducted experiments showing that the transposon--which they dubbed "Sleeping Beauty" because it had been "awakened" after millions of years of inactivity--could jump into the chromosomes of fish, mice, and even humans. The researchers then utilized the transposon to carry new genes into zebra fish and other animals. Now Hackett aims to develop it for use in gene therapy.BY JOHN CAREYReturn to top
A TOOL FOR STAYING A STEP AHEAD OF HIV
POWERFUL DRUG COCKTAILS ARE KEEPING HIV at bay in thousands of people infected with the virus. But given the deadly virus' ability to mutate rapidly, patients are worried that their viral strains will develop resistance to the treatments. Indeed, HIV has already proven that it can quickly develop resistance to single-drug treatments. And doctors increasingly are dealing with patients in whom levels of the virus are creeping back up.
But there may be a way to head off resistance before it occurs. By reading the genetic codes of viruses as they mutate and evolve in actual patients, Robert M. Lloyd Jr., scientific director at Applied Sciences Inc. in Norcross, Ga., made a critical discovery. Before a strain of virus actually mutates enough to become resistant, he found, it typically makes an intermediate change in its genetic code. That mutation, Lloyd reasoned, can be used to predict later mutations that lead to resistance.
By searching for these intermediate mutations, "we can have a crystal ball of what resistance mutations are coming," explains John Stevens, chief executive officer of Visible Genetics Inc. in Toronto, which owns Applied Sciences.
Once a "crystal ball" mutation is spotted, it may be possible to change the combination of drugs to prevent resistance from developing.BY JOHN CAREYReturn to top