Health briefs: Advance in search for HIV vaccine

Small advancements make big waves in the decades-long search for an HIV vaccine, and University of Miami researchers are optimistic that their latest findings are significant: They have developed a vaccine that triggers an immune system response strong enough to kill a model AIDS virus in mice.

The vaccine is still in the early stages, said Geoffrey W. Stone, an assistant professor of microbiology and immunology who led the research study published in the Journal of Virology. "But in those modest beginnings, we have had some very dramatic results."

The vaccine developed by Stone and his team can prevent mice from becoming infected with HIV, he said, by targeting a specific receptor in the immune system to trigger a significant T-cell response to the virus.

The receptor is called CD40, and the vaccine uses a form of the receptor's natural binding protein to enable the immune system's dendritic cells to signal the presence of HIV. "We're trying to get a magic bullet," Stone said, "that can bring information about HIV to dendritic cells."

Unlike standard vaccines, which use untargeted antigen to generate an immune response, this approach attaches an HIV antigen to the binding protein, which then generates the better immune response. The next step is trials on larger animals.

It may be a good idea to get a blood pressure reading in both arms rather than just one. A difference in those readings, a new study suggests, is an independent risk factor for heart disease.

Using data from a health study, researchers examined 3,390 people 40 or older who were free of cardiovascular disease, following them for more than 13 years. During the study period, 598 participants had a first heart attack, stroke or other cardiovascular problems. More than a quarter of those had a difference in systolic blood pressure, the upper number in a blood pressure reading (which is measured in millimeters of mercury), of 10 or greater between one arm and the other.

Doctors' stethoscopes are contaminated with bacteria that can easily be transferred from one patient to another.

Researchers cultured bacteria from the fingertips, palms and stethoscopes of three doctors who had done standard physical examinations on 83 patients at a Swiss hospital. They tested for the presence of viable bacterial cells, looking for the potentially deadly methicillin-resistant Staphylococcus aureus, or MRSA. The study appears in the March issue of Mayo Clinic Proceedings.

Fingertips on the doctors' dominant hands were the most contaminated areas studied, but the part of the stethoscope that touches the patients' skin had more than twice as much bacteria as the physicians' palms. The stethoscopes were more contaminated with MRSA than some parts of the palms, but not others.

The authors acknowledge that the study was small. But Dr. Didier Pittet, senior author and a professor of medicine at the University of Geneva Hospitals, said, "It may be time to have one stethoscope per patient, at least in ICUs."