Developments to Watch
TAKING THE PULSE OF HEART RESEARCH
From soybeans to radiation--a roundup of the latest findings
Last week was a bad time to try to find a cardiologist anywhere outside New Orleans, where more than 30,000 of them convened at one of the largest medical meetings in the world--the annual scientific meeting of the American Heart Assn. Up-to-the-minute reports on new drugs, surgical techniques, and heart-attack prevention were among the subjects of nearly 5,000 presentations. Senior Editor Paul Raeburn reports.EDITED BY NAOMI FREUNDLICHReturn to top
TOFU MAY BE GOOD FOR THE TICKER
RESEARCHERS HAVE LONG sought to explain why rates of heart disease and breast cancer are four times higher in the U.S. than in Japan. Now they may have found part of the answer: the lowly soybean.
Soybeans, virtually absent from the American diet, are a major source of dietary protein in Japan. Dr. Gregory L. Burke of the Bowman Gray School of Medicine in Winston-Salem, N.C., found that a supplement of 20 grams of soy protein per day--comparable to the amount in the Japanese diet--lowered total cholesterol 10%. It also produced a slight rise in high-density lipoproteins--the form of cholesterol that protects against heart disease.
Other studies have suggested that soybeans might protect against some cancers, including breast cancer. They may also help reduce "hot flashes" associated with menopause. The key ingredients are so-called phytoestrogens, substances that can mimic the effects of human estrogen. How these compounds protect against heart disease and cancer is still not clear.
Soy protein supplements are widely available in health-food stores, but scientists aren't recommending their use until more research is in.EDITED BY NAOMI FREUNDLICHReturn to top
CASTING DOUBT ON AN OLD ALLY
THE NATION'S CARDIOLOGISTS are recommending against the use of a popular class of drugs--calcium-channel blockers--to treat heart attacks. In new guidelines, the American Heart Assn. and the American College of Cardiology say the drugs "have not proven beneficial in early treatment or secondary prevention" of heart attacks, and may even be harmful.
The drugs--which relax blood vessels--became the focus of controversy following a March, 1995, report that they were statistically associated with a 60% rise in the risk of heart attack. Newer studies have added to the concern and raised the question whether calcium-channel blockers can increase the risk of cancer, too. Bruce M. Psaty, an epidemiologist at the University of Washington and the author of the 1995 study, said the new guidelines accurately reflect the latest scientific data.
Dr. Roger Sachs, a vice-president at Pfizer Corp., maker of calcium-channel blocker Procardia, says the drugs are used primarily for treating chest pain and hypertension, not heart attacks. And he questions the evidence linking calcium-channel blockers to cancer. The worldwide market for the drugs is $6 billion.EDITED BY NAOMI FREUNDLICHReturn to top
NEW HELP TO KEEP ARTERIES CLEAR
ADVANCES IN THE USE OF tiny balloons to open clogged arteries have been marred by a recurrent problem. In about 30% of patients who undergo balloon angioplasty, the newly opened arteries become clogged again, necessitating further treatment. But researchers have found that inserting specks of radioactive iridium into blood vessels reduces the cell growth that can lead to re-blockage.
Surgeons often place small metal tubes called stents in newly cleared arteries to keep them open. Stents prevent the collapse of arteries, but they don't stop troublesome cell growth. That's where radiation comes in. After inserting stents, Dr. Paul S. Teirstein and colleagues at the Scripps Clinic in La Jolla, Calif., used a long tube to deliver specks of iridium to the opened arteries. The iridium was left for 30 minutes, then removed. Six months later, 54% of the 29 patients given only stents experienced renarrowing of their arteries. Of the 26 given stents plus radiation, only 15% experienced renarrowing. Researchers have noted no adverse side effects, and a second, larger trial is currently under way.EDITED BY NAOMI FREUNDLICHReturn to top