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Protein Tags To Chase Down Tumors


Developments to Watch

PROTEIN TAGS TO CHASE DOWN TUMORS

CHEMOTHERAPY DELIVERS A powerful punch to some tumors, but it can damage the patient's organs and weaken the immune system. That's why doctors long for a magic bullet that would target only the tumor. They've tried anchoring drugs to antibodies that home in on specific sites. But these tend to be large molecules that don't penetrate tumors easily.

In the Mar. 28 issue of Nature, scientists at the Burnham Institute in La Jolla, Calif., describe a new method for generating small protein "tags" that can find their own way to specified "addresses" in the human body. Institute President Erkki Ruoslahti, a molecular biologist, and colleague Renata Pasqualini generate randomly shaped protein structures on the outer coating of billions of viruses. Injected into mice, the altered viruses bind to cells whose receptors match their protein structures. Scientists then remove the target organs--here, the brain and kidney--grind them up, and isolate viruses bound there.

In the case described in Nature, researchers found just three types of altered viruses in the brain and one type in the kidney. Their conclusion: These viruses contained the right protein tag required to bind with cells in those two organs. The researchers then cloned and cultured the viruses and isolated the DNA that generates the desired protein structures. The protein tags can be coupled with drugs or genes for delivery to the appropriate organ, says Ruoslahti. His lab is using the method to find tags for blood vessels that nourish tumors.EDITED BY NEIL GROSS By David GrahamReturn to top

FEWER PINPRICKS FOR DIABETICS

TO KEEP TABS ON THEIR glucose levels, many diabetics observe a ritual of pricking their fingers with a needle several times a day to draw a drop of blood. Insulin-pump maker MiniMed Inc. of Sylmar, Calif., has an alternative: an implantable glucose sensor that may be on the market in two or three years. Inserted by the user just under the skin of the abdomen, the small pin would need replacing only once every three days.

The pin contains tiny electrodes that, upon contact with glucose, produce electrochemical reactions. A button-size connector attached to the pin interprets them, sending radio signals to a wristwatch-like reader. This displays the user's glucose level and alerts the wearer to any sudden changes with a series of beeps.EDITED BY NEIL GROSSReturn to top

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WORKERS WITH FLEXTIME GET SOME HEARTENING NEWS

WHO'S AT HIGHER RISK OF DYing of a work-related heart attack: a hard-driving prosecutor who puts in 80-hour weeks or a 9-to-5 assembly-line worker? Surprisingly, the prosecutor may face a lower risk, according to a 14-year study of some 12,500 Swedish male workers published in the March issue of the American Journal of Public Health. The real culprits in these attacks seem to be a sense of isolation and lack of control over one's job.

Assembly-line workers, of course, aren't the only ones who fit that bill. A white-collar worker with an authoritarian boss may be in just as much danger. According to one of the study's authors, Walter Stewart, associate professor of epidemiology at Johns Hopkins School of Public Health, a worker who feels like a cog in a machine has a 162% higher risk of dying from a heart attack than one who has a lot of input and works in a team. And that sense of belonging may have other benefits: higher worker productivity and less absenteeism. What causes the attacks? Stewart says elevated blood pressure could be the key.EDITED BY NEIL GROSS By Naomi FreundlichReturn to top


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