Health Headlines - June 25

New Test May Offer Alzheimer's Insights

U.S. researchers hope to answer an important and long-vexing question about the origins of Alzheimer's disease: Do patients with the condition have high levels of a brain protein because they make too much of it or because they can't clear it from their brains fast enough?

Scientists at the Alzheimer's Disease Research Center at Washington University School of Medicine in St. Louis say they have developed the first safe and sensitive way to monitor the production and clearance rates of amyloid beta peptide (Abeta) in the human central nervous system. The new testing process could open an important window into the origin of Alzheimer's disease that, in addition to helping scientists better understand the source of the condition, will likely help them improve its diagnosis and treatment, the researchers said.

High levels of Abeta in the brain are a hallmark of Alzheimer's disease and are believed to be a key cause of the condition. Tests that measure Abeta levels in the cerebrospinal fluid have been available for some time. However, those tests gave no hint as to whether Abeta in patients' brains came from an increase in the mechanisms that make the protein or a reduction in the processes that regularly clear it from the brain, the researchers said.

Because Alzheimer's symptoms take many years to develop, some researchers had assumed the creation and clearance rates for Abeta were very slow. But the initial test of the new technique, applied to six healthy volunteers, suggests the opposite.

"Abeta has the second-fastest production rate of any protein whose production rate has been measured so far," says lead author Dr. Randall Bateman, assistant professor of neurology at the school. "In a time span of about six or seven hours, you make half the amyloid beta found in your central nervous system."

Ideally, the production and clearance rates stay balanced, causing the overall amount of Abeta in the central nervous system to remain constant. In the healthy volunteers who were the first test subjects, Bateman found the production and clearance rates were the same. He is now applying the technique to individuals with Alzheimer's disease.

Researchers are developing Alzheimer's drugs that either decrease Abeta production or increase its clearance, Bateman said, and the new test could be important in determining which approach is most effective.

The test also may be useful in the diagnosis of Alzheimer's prior to the onset of symptoms, which appear after the disease has inflicted widespread and largely irreversible damage to the brain.

The study appears online June 25 in the journal Nature Medicine.

HIV Drug Approved for Those Not Responding to Existing Drugs

The U.S. Food and Drug Administration on Friday approved Prezista (darunavir), a new drug for adults whose HIV infection hasn't responded to treatment with other antiretroviral drugs.

Prezista, a new protease inhibitor, is approved to be used with a low-dose of ritonavir and other active anti-HIV agents. Ritonavir, a protease inhibitor approved in 1996, slows the breakdown of Prezista in the body, increasing the concentration of Prezista in the patient's system, the FDA said.

HIV causes AIDS, which results in more than 15,000 premature deaths each year in the United States and more than 2.8 million deaths each year worldwide.

"This approval offers new hope to HIV patients who too often urgently need new therapies in order to maintain their health," said Dr. Andrew C. von Eschenbach, acting FDA commissioner. "This drug is not a cure, but when combined with other standard therapies, it presents one more major step in our effort to help patients combat the effects of the disease."

Losing Weight Helps People With Osteoarthritis

Patients with knee osteoarthritis who lose weight are significantly less disabled and are better able to manage pain, a new study found.

"Weight-reduction therapy in overweight osteoarthritic patients is a very appealing goal, both with regards to disease specific pain and disability reduction as well as for overall health benefits such as cardiovascular risk reduction" said study author Robin Christensen, of The Parker Institute, HS Frederiksberg Hospital, in Copenhagen, Denmark.

The findings were presented Saturday at the 2006 European League Against Rheumatism Congress, in Amsterdam, the Netherlands.

Osteoarthritis is the most common form of joint disease, and is often associated with significant disability and an impaired quality of life. A number of studies had suggested a relationship between weight loss and health gains in patients with knee osteoarthritis. This led the Danish researchers to launch a "meta-analysis" of existing research to see if weight loss really did offer health gains.

The researchers reviewed 23 clinical trials. Their conclusion: The evidence shows that osteoarthritis patients will experience at least a "moderate clinical effect in their physical disability (ES>0.5) with a moderate dietary regime following more than 7.6 percent weight reduction.

"A 10 percent reduction in body weight results in a moderate-to-large improvement in self reported physical disability," Christensen said.

Rheumatoid Arthritis Diminishes Patients' Sex Lives

One-third of patients with rheumatoid arthritis feel their condition has a "considerably" negative influence on their sex lives, new research finds.

"Today's findings indicate the need for increased attention on the effect of rheumatoid arthritis on sexual activity as well as reveal that sexual problems should be addressed as part of the general health care given to RA patients," said Ylva Helland, department of rheumatology at Diakonhjemmet Hospital in Oslo, Norway.

The findings were presented Saturday at the 2006 European League Against Rheumatism Congress, in Amsterdam, the Netherlands.

The study found that 31 percent of RA patients reported that the disease had no impact on sexual activity, with another 38 percent saying it had "little" impact. But, 21 percent said their condition had considerable impact on their sex lives, and 10 percent said RA made sexual activity either almost or totally impossible.

Compared to the female patients, men were more likely to report a significant impact on their sexual activity.

Human Bird-Flu Transmission Confirmed in Indonesian Cluster

The first case of human-to-human transmission of the bird flu virus has been confirmed in laboratory tests of samples taken from a 10-year-old Indonesian boy who died last month from the H5N1 avian influenza strain, a World Health Organization official said Friday.

Genetic sequencing of a virus sample taken from the boy showed a minute change that was also found in a sample taken from his father, who also later died, said Dick Thompson, a spokesman for the United Nations health agency in Geneva, Switzerland. Human-to-human transmission had been suspected as the cause of the infection in seven members of a family of eight from the island of Sumatra.

The Sumatran cluster attracted international attention because it represented the largest reported instance of bird-flu spread among people and the first evidence of a three-person chain of infection.