News in brief - May 12, 2003

CDC expands groups targeted for early flu vaccinations - Mammography decreases breast cancer deaths - Baby teeth a haven for stem cells - High fiber means low cancer - Drug spurs diabetes prevention

CDC expands groups targeted for early flu vaccinations

Flu shot distribution this October should target those older than 50, infants 6 months or older, children younger than 9 and anyone with preexisting conditions that put them at high risk for influenza complications. Contacts of those at high risk and health workers also should be vaccinated in October, according to recommendations from the Centers for Disease Control and Prevention's Advisory Committee on Immunization Practice, published in the April 25 Morbidity and Mortality Weekly Report.

Vaccination efforts should not target others until after Nov. 1, although the agency recommended that if low-risk people ask for the vaccine in October, they should not be turned away. The agency also announced that this year's strains included in the vaccine will be Moscow A, New Caledonia A and Hong Kong B. Information about this year's supply will be available at the end of the summer.

Mammography decreases breast cancer deaths

Screening for breast cancer with mammography reduces the number of deaths associated with the disease, according to two studies published in the April 26 Lancet. Researchers in Sweden and The Netherlands studied breast cancer death rates before and after the introduction of screening programs.

The Swedish study found that women ages 40-69 who received mammography after widespread screening was introduced had a 44% reduced risk of dying from breast cancer. The Dutch study found that death rates among women ages 55-74 decreased by a fifth after the introduction of screening.

Researchers said these decreases could not be accounted for by improvements in medical care because women diagnosed with breast cancer who were never screened had a mortality reduction of only 16%.

"Taking account of potential biases, changes in clinical practice and changes in the incidence of breast cancer, mammography screening is contributing to substantial reductions in breast cancer mortality in these two countries," said Laszlo Tabar, MD, lead author of the Swedish paper and director of mammography at Sweden's Falun Central Hospital.

Baby teeth a haven for stem cells

Scientists are reporting that children's baby teeth contain a rich supply of stem cells in their dental pulp. The cells remain alive inside the tooth for a short time after it falls out of a child's mouth, thus suggesting the cells could be harvested for research.

The findings were published in the April 21 online edition of the Proceedings of the National Academy of Sciences.

"Doctors have successfully harvested stem cells from umbilical cord blood for years," said Songtao Shi, DDS, PhD, a scientist at the National Institutes of Health National Institute of Dental and Craniofacial Research.

"Our finding is similar in some ways," said Dr. Shi, "in that the stem cells in the tooth are likely latent remnants of an early developmental process.

Dr. Shi's finding resulted from his helping his then-6-year-old daughter pull out a loose baby tooth. Noticing that the tooth had red-colored tissue inside, he examined it in his lab. "Sure enough," he said, "it had beautiful pulp tissue left over."

High fiber means low cancer

Two new studies are providing evidence that a high-fiber diet does contribute to substantially lowering the risk of colon cancer. The new studies contradict other recent findings that had suggested there was no association between increased fiber intake and reduced risk of colorectal cancer.

In the first study, researchers compared the relation of fiber intake and frequency of colorectal adenoma in about 34,000 participants of the U.S. Prostate, Lung, Colorectal and Ovarian Cancer Screening Trial who did not have polyps, to about 3,600 people who had at least one adenoma in the distal large bowel.

Participants in the top 20% for dietary fiber intake had about a quarter lower risk of adenoma compared with people in the bottom 20% for fiber intake, said the researchers. The association was strongest for fiber from grains, cereals and fruits.

The second study was conducted in Europe and found a similar link between diet and colorectal cancer in more than half a million individuals recruited from 10 countries.

After 4 ½ years of follow-up, 1,065 cases of colorectal cancer were diagnosed. Individuals from the top 20% for fiber intake, eating about 35 grams of fiber per day, reduced their risk of colorectal cancer by about 25%, compared with individuals who consumed 15 grams of fiber per day on average.

Both studies were published in the May 2 Lancet.

Drug spurs diabetes prevention

A new study showed that an anti-inflammatory drug called lisofylline, originally developed as an infection-fighter for cancer patients, could be beneficial for people at risk for type 1 diabetes.

Researchers at the University of Virginia Health System in Charlottesville discovered that two weeks of lisofylline treatment reduced the incidence of type 1 diabetes in mice to 25% compared with 92% in mice who did not receive lisofylline. Diabetes was induced in mice by multiple low doses of a certain drug.

The UVA researchers say lisofylline protects insulin-producing cells by inhibiting the production and action of pro-inflammatory cytokines, proteins produced by immune cells that can cause death and dysfunction. Importantly, the treatment also restored insulin secretion, said the study.

The research was published in the April 30 online issue of Pancreas.