The anti-cancer effects of a diet high in soy may result from a chemical contained in soy called genistein. Asians, who eat 20 to 50 times more soy than Americans, have a fairly low risk of developing cancers of the prostate, breast and colon. Most researchers attribute that low risk to diet.
Molecular biologist Amy S. Lee and her colleagues at USC report in the March 4 Journal of the National Cancer Institute that genistein turns off a defense mechanism that cells use to survive under stressful conditions, such as starvation, malnutrition, lack of oxygen, extreme heat and cancer. In cancer cells, researchers believe stress-defense proteins inadvertently worsen disease, helping tumor cells elude the immune system and resist chemotherapy. The researchers do not yet know if administering genistein will inhibit tumor growth, however.
Flight Attendants More Prone to Miscarry
Flight attendants who continue to work while pregnant about double their risk of having a miscarriage, UC San Francisco researchers report in the March issue of the Journal of Occupational and Environmental Medicine. Dr. James E. Cone and his colleagues studied 418 flight attendants with recent pregnancies.
They found that 15% of women who continued to fly during their pregnancies had miscarriages--also called spontaneous abortions--compared with 8% of those who did not fly. There is a 10% to 20% risk of miscarriage in the general population, Cone said.
MRI Device Measures Heart Muscle Damage
The amount of damage to heart muscle after a heart attack can be measured noninvasively with a variant of magnetic resonance imaging, researchers from Johns Hopkins Hospital report in the March 7 Lancet. They used the MRI instrument to measure levels of creatine, an amino acid, in heart tissue. Healthy tissue normally contains relatively high levels, while damaged tissue contains much less.
The team studied 10 healthy volunteers and 10 patients with a history of heart attacks. They found that they could easily identify regions of damaged muscle and suggested that the technique could be widely used for monitoring the aftermath of heart attacks.
White Males Get Liver Transplants Fastest
Women, minorities and children wait longer than white males for liver transplants, according to a study by researchers at the Johns Hopkins School of Public Health. Liver transplants account for 20% of all transplants performed and are the most expensive, with a median cost of about $186,000 in 1992.
The team studied records from the United Network for Organ Sharing, which coordinates organ procurement. They report in the March 5 issue of Medica Care that women wait an average of 110 days, compared with 91 for men. Asian Americans waited 138 days, and Hispanic Americans 107 days. Children waited an average of three weeks longer than adults.
More Fatal Heart Attacks for Diabetics on Sular
Diabetics taking the calcium channel blocker nisoldipine (sold as Sular) to combat high blood pressure are significantly more likely to die of a heart attack than those taking the ACE inhibitor enalapril (sold as Vasotec), Colorado researchers report in the March 5 New England Journal of Medicine.
The team studied 470 diabetics with high blood pressure, half of whom received Sular and half Vasotec. There were 25 fatal and nonfatal heart attacks in the group taking nisoldipine compared with only five in the group taking enalapril. Physicians cautioned, however, that patients should not stop taking nisoldipine without consulting their doctors.
Higher Levels of DHEA Good News for Older Men
Older men with the highest blood levels of the hormone dihydroepiandrosterone (DHEA) have a more favorable pattern of risk factors for heart disease than do men with lower DHEA levels, according to a report in the March Journal of the American Geriatrics Society. A similar effect was not observed in women, however, according to a team from the Medical College of Milwaukee.
Men with the higher levels of DHEA had a lower percentage of body fat, higher levels of high-density lipoprotein (HDL), the so-called good cholesterol, higher levels of testosterone and better performance on an exercise test. But the researchers could not conclude whether the high hormone levels produced the better risk factors or vice versa. They also could not tell if taking DHEA pills improved the risk factors.