Behavior: A to Z Guide

A

ALZHEIMER'S

New estimates show that by 2050, a record 13.2 million older Americans will be affected by the progressive brain disease, 3 million more than previous projections. Although the illness is still definitively diagnosed only at autopsy, advances are being made in finding it earlier. Doctors can improve the accuracy of detection 30% by combining various cognitive tests with positron-emission tomography (PET). PET is an imaging technique that shows the brain's metabolism at work. Preliminary research suggests that it may also be possible for physicians to detect certain telltale signs of Alzheimer's disease--the so-called amyloid and tau proteins--in the spinal fluid.

Of course, knowing you have early Alzheimer's doesn't help much if it can't be treated. Fortunately, therapies are improving. Exelon and memantine, drugs usually used to treat the symptoms of dementia in moderate cases of Alzheimer's, may be even more useful in delaying the progression of early disease.

Neuroscientists were disappointed two years ago when a potential vaccine for Alzheimer's disease ended up causing severe inflammation of the brain. (One woman died several months after being vaccinated. Further study confirmed that her brain was inflamed, though some of her brain plaques, a symptom of Alzheimer's, seem to have shrunk.) Doctors are making progress toward finding ways to avoid the inflammation.

AIDS

AIDS is still a death sentence in much of world, so President Bush pledged $15 billion over the next five years for the relief of the disease in the most severely affected nations of Africa and the Caribbean. At least $10 billion a year is needed, according to U.N. estimates, but the world's richest countries spend a total of about $2.8 billion annually.

In the U.S., experts reported that for the first time since the mid-1990s, the number of HIV infections rose, by 1%. They believe some of the climb can be traced to the fact that more and more HIV patients are living longer, thanks to a potent combination of drugs that can control the virus. Unfortunately, if survivors fail to follow prevention guidelines, they may pass HIV along to others.

There were disappointing results on the research front as well. Scientists found that some anti-AIDS therapies seem to increase the risk of heart attack 25%, at least in the first few years of treatment. In addition, studies showed that taking a break--or "drug holiday"--from the grueling pill-popping schedule does not improve the body's ability to overcome drug-resistant forms of HIV.

The first vaccine to be widely tested in humans failed to protect test subjects from HIV. But the information gained should help in the development of future vaccines.

ANTIBIOTICS

Babies who are 6 months old or younger face a risk when given antibiotics for the first time. A Detroit study found that such infants were 1 1/2 times as likely to develop allergies and twice as likely to develop asthma as babies who didn't take the drugs. But exposure to dander from two or more household pets seems to reduce these risks.