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A Trojan Horse To Fight Malaria


Developments to Watch

A TROJAN HORSE TO FIGHT MALARIA

THE NUMBERS DEFY THE imagination: 1 million children killed every year, 200 million people afflicted. Malaria is steadily gaining resistance to medicine's scant arsenal of drugs. Although Americans think of malaria as a Third World disease, the mosquitoes that carry it are found in North America and could easily become infected with drug-resistant strains.

The good news is, the plasmodium parasite that causes malaria has chinks in its armor, and Stanford University biochemist Kasturi Haldar and her colleagues think they have discovered one. At a late stage in the parasite's life cycle, the plasmodium hides in a small sack inside a host's red blood cells and extends a tangle of membranes to the surrounding plasma. The membranes import nutrients from the bloodstream, writes Haldar in a recent issue of the journal Science.

The plasmodium's membranes could provide an important target for antimalaria drugs. The researchers demonstrated that this lifeline will import toxins that closely resemble nutrients. The toxins' chemical structure is very different from that of today's quinoline-based drugs. So if drugs are designed around these nutrient look-alikes, "there's no reason there should be any resistance," Haldar says.EDITED BY NEIL GROSSReturn to top

SENDING TUMOR CELLS TO HOG HEAVEN

DOCTORS STUDYING `TRANSspecies transplants' are awed by the fury of the human body's rejection of animal organs. SangStat Medical Corp. in Menlo Park, Calif., is trying to harness that power to destroy tumor cells by making them look like pig cells, says Dr. Wayne Hancock, an associate professor at Harvard Medical School who collaborates with the company.

Pig cells have sugars on their outer membranes that trip the immune system. Detection of the sugars activates the "complement reaction"--a cascade of enzymes that destroys foreign cells.

To make tumor cells look like pig cells, SangStat researchers attach the porcine sugars to a protein called transferrin that binds with iron. Cancer cells need more iron than normal cells because they divide rapidly. As the cancer cells consume iron, the transferrin and pig sugars accumulate on tumor cells, setting off an immune system "rejection" of the tumor cells.

Hancock says the method has provoked tumor rejection in mice. But there is a risk of side effects, because transferrin is also used by cells in bone marrow and the digestive system. To skirt this problem, SangStat is testing other cancer-specific proteins to find alternate carriers for the pig sugars.EDITED BY NEIL GROSS Naomi FreundlichReturn to top

NOW, THAT'S DIGITAL SECURITY

PASSWORD SECURITY SYSTEMS MAKE LIFE VERY EASY for hackers. Many people still rely on easily guessed variations of birth dates and phone numbers. Systems that recognize fingerprints are harder to hack, but the equipment, such as touchpads, can add $300 to the cost of a PC, bank ATM, or other protected terminals.

A Lucent Technologies Inc. spin-off called Veridicom Inc. in Menlo Park, Calif., plans to bring the cost of such systems below $100 early next year. Using patented Bell Labs technology, Veridicom has made a postage stamp-sized silicon chip that fits on a keyboard key. It measures the ridges and valleys of a user's index finger, identifies unique markers called minutiae, and matches them against a software template in the chip's memory.

The approach isn't hack-proof. In theory, a thief could intercept the 300-odd bytes of data that make up a digital image of a finger and feed the data directly to a secured PC or ATM--without ever placing a finger on the sensor. To prevent this, Veridicom intends to build powerful encryption into its chip. Instead of storing a precise map of the fingertip, the template will represent a complex mathematical problem whose solution lies in the combination of angles in the lines of the finger. Since the template exists only on the chip, hackers won't find it in any corporate database. Can the chip itself be hacked? Probably, says Veridicom President Thomas E. Rowley, "but it's still a lot safer than a password."EDITED BY NEIL GROSSReturn to top


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