WEDNESDAY, May 28 (HealthDay News) -- A gene that plays a role in Alzheimer's disease in two large families in which many siblings suffer from the neurodegenerative condition has been identified by U.S. researchers.

Identification of this gene -- TRPC4AP on chromosome 20 -- opens a new line of research that may help improve understanding of what causes Alzheimer's disease.

TRPC4AP is involved in calcium regulation. It's known that when calcium levels aren't carefully controlled, cells can die, leading to the onset of disease.

In this study, researchers at the Medical College of Georgia and the VA Medical Center in Augusta focused on two large families with a history of late-onset Alzheimer's disease who were enrolled in a DNA bank. Both families had 15 siblings, five of whom had Alzheimer's. Analysis of blood samples revealed that all the patients in both families had the same pattern of single nucleotide polymorphisms (SNPs), which are single base changes in gene structure found throughout DNA.

When they analyzed samples from other Alzheimer's patients in the DNA bank, the researchers found that 36 percent had the same pattern of SNPs as the patients in the two families.

The study was published in the current issue of the American Journal of Medical Genetics Part B: Neuropsychiatric Genetics.

"The use of extended pedigrees is vital for genetic studies. The next step will be to identify the exact mutation in this gene which is causing the disease. The DNA is currently being sequenced to find this mutation," study author Dr. Shirley Poduslo said in a prepared statement.

"The long-term significance will be to understand the mechanism of the disease so that more effective drugs can be designed to slow the progression of the disease, delay the onset, identify patients early in the disease course and, hopefully, someday to keep this dreadful disease from occurring," Poduslo said.

More information

The National Institute on Aging has more about Alzheimer's disease.

MONDAY, May 26 (HealthDay News) -- Elderly people with dementia who are given antipsychotics, even for a very short period of time, are more likely to end up in the hospital or even die, new research shows.

However, the problems underlying the need for such medications, behavioral problems such as aggression and agitation, are very real, and the alternatives to antipsychotics are limited, the researchers added.

"A misreading of the findings would be we don't need to do something for these nursing home residents," said study author Dr. Gary J. Kennedy, head of geriatric psychiatry for Montefiore Medical Center in New York City.

Many experts feel behavioral interventions should be tried first and antipsychotics used as a last resort, "when the behavior or the psychiatric symptoms are really out of control and causing complete distress not only for the person suffering from Alzheimer's, but for caregivers all around them," said Maria Carrillo, director of medical and scientific affairs at the Alzheimer's Association in Chicago. "It's important to work these things out with the physician and, of course, do follow-up very closely together, so you can make sure these antipsychotics are having the effect you want and, if not, discontinue them immediately."

The findings were published in the May 26 issue of the Archives of Internal Medicine.

Antipsychotic drugs are commonly used to treat some of the behavioral complications of dementia, including delirium.

Newer antipsychotic medications such as Zyprexa (olanzapine) and Risperdal (risperidone) have been available for about a decade and have largely replaced their older counterparts.

Researchers from the Institute for Clinical Evaluative Sciences in Ontario, Canada, compared 20,682 older adults with dementia living in the community with 20,559 older adults with dementia living in a nursing home between April 1, 1997, and March 31, 2004.

Each group was divided into three subgroups: those not receiving any antipsychotics, those taking newer antipsychotics, and those taking older antipsychotics such as Haldol (haloperidol).

According to information gleaned from medical records, community-dwelling adults who had recently received a prescription for a newer antipsychotic medication were 3.2 times more likely than individuals who had received no antipsychotic therapy to be hospitalized or to die during 30 days of follow-up.

Those who received older antipsychotic therapy were 3.8 times more likely to have such an event, relative to their peers who had received no antipsychotic therapy.

A similar pattern, albeit less dramatic, emerged in the nursing home group. Individuals taking older antipsychotics were 2.4 times more likely to be hospitalized or die, while those taking newer drugs were 1.9 times more likely to die or be hospitalized during the 30 days of follow-up.

The study does, however, have its limitations. "It's a carefully done study," Kennedy said. "One flaw is that the [participants] weren't randomly administered antipsychotics. There was some reason they were given an antipsychotic, such as aggression or agitation. It may have been done if they were recently admitted to the nursing home as part of the adjustment process.

Indeed, the authors acknowledged that about 17 percent of patients entering nursing homes start taking an antipsychotic within 100 days.

"For any of us, moving is like being sick. It takes a while to recover," Kennedy said. "We need other sets of interventions besides medications. What that implies is more staffing and better training for staff, and that may not be a whole lot more expensive than medicines."

More information

The Alzheimer's Association has a statement   on treating behavioral and psychiatric symptoms in Alzheimer's patients.

MONDAY, May 26 (HealthDay News) -- Using a cane may help reduce the risk of knee osteoarthritis (OA) progression, according to a study by researchers at the University of Melbourne in Australia.

The study included 16 men and 24 women, mean age 65, with knee OA, an incurable joint disease that's the leading cause of disability in elderly people. All the participants walked in their bare feet and then in their own shoes. Then, 20 of the participants walked wearing their own shoes and using a cane in the hand opposite to the knee with OA.

During these tests, the participants walked over sensors that recorded ground impact. The researchers also gathered data on limb movement.

Overall, the peak knee adduction moment -- an indication of weight placement while walking -- was 7.4 percent higher when wearing shoes than when walking barefoot. Use of a cane resulted in a 10 percent average decrease in the knee adduction moment. Some of the participants had a more than 20 percent decrease when using a cane.

While the participants tended to walk more slowly while using the cane, they had greater stride length and improved pelvis control, which alleviates the damaging load on the knee with OA.

The study was published in the journal Arthritis Care & Research.

While canes are already widely recommended for patients with knee OA, this study confirms their therapeutic value, at least in the short-term, the researchers said.

"Further studies are required to establish whether knee loading remains lower with ongoing use of a cane and whether the reductions in loading translate to a reduced risk of disease progression," study author Dr. Rana S. Hinman said in a prepared statement.

It's not clear why wearing shoes increased the peak knee adduction moment, but heel height, sole thickness, and arch supports may all be factors.

"Because it is potentially dangerous as well as impractical to advise patients with knee OA to walk about in bare feet, further research is needed to determine which types of shoes least increase the knee adduction moment or, ideally, reduce it," Hinman said.

More information

The Arthritis Foundation has more about osteoarthritis  .