WEDNESDAY, April 23 (HealthDay News) -- An enzyme shown to help suppress development of Alzheimer's disease appears to hasten progress of a related but far less common type of dementia, according to a new study.

The surprising findings, published in the April 22 online issue of The Journal of Clinical Investigation, are significant, because individuals with frontotemporal dementia with parkinsonism-17 -- a relatively rare hereditary form of dementia -- are often used as models for studying Alzheimer's disease.

Alzheimer's disease and frontotemporal dementia each develop as a result of too many tau proteins accumulating and causing tangled lesions in the brain's neurons. These knotted nerve cells eventually choke off the brain cells responsible for memory.

However, individuals with frontotemporal dementia have mutations in the gene, known as P301L, encoding tau. These mutations have not been found in individuals with Alzheimer's.

Researchers found in mouse models and human cells that boosting levels of the prolyl isomerase (Pin1) enzyme, previously shown to aid in "detangling" tau in Alzheimer's disease, helps break down the tau proteins. However, the same experiments on mice with the genetic mutations in the tau that cause frontotemporal dementia resulted in increased and accelerated tau protein tangling.

"First, we have established a proof of concept that boosting Pin1 activity may offer a new idea for preventing or even treating the tau pathology and neurodegeneration in Alzheimer's disease," senior author Kun Ping Lu, a scientist in the Division of Hematology/Oncology at Beth Israel Deaconess Medical Center, said in a prepared statement. "And, second, given that no tau mutation is found in Alzheimer's patients, this research suggests that it would be prudent to not use P301L tau as an Alzheimer's disease model, especially when screening and testing drugs, as it may produce diametrically opposite effects."

More information

The Alzheimer's Association has more about current treatments for Alzheimer's  .

TUESDAY, April 22 (HealthDay News) -- Nursing home patients who take antipsychotic drugs are 60 percent more likely to develop pneumonia in the short term than those who don't take the drugs, a new study shows.

The risk is greatest during the first week after patients start taking the medications and gradually decreases, say Dutch researchers.

"The risk of developing pneumonia is not associated with long-term use, but is the highest shortly after starting the drug," said study authors Dr. Rob van Marum and Dr. Wilma Knol. They warned that "all antipsychotic drugs may be associated with pneumonia in elderly patients."

This is the first study to show an association between pneumonia risk and the use of antipsychotic drugs, which are frequently used to treat psychosis and behavioral problems in elderly patients with dementia and delirium.

The study was published in the current issue of the Journal of the American Geriatrics Society.

More research is needed to identify the underlying mechanism behind this association, said the researchers, who added that doctors should monitor elderly patients for signs of sedation after they start taking antipsychotic drugs and should carefully weigh the possible risks before they prescribe antipsychotic drugs for elderly patients.

Up to 40 percent of nursing home residents may be prescribed antipsychotics, according to the study authors. They noted that, in more than half of those cases, antipsychotics are prescribed for inappropriate reasons. The drugs are often used to treat behavioral problems in dementia patients, but evidence shows these drugs have limited effectiveness in these patients.

In addition, recent research has shown that the use of antipsychotic drugs in elderly patients is associated with an increased risk of illness and death.

More information

The American College of Physicians has more about antipsychotic drug use and death in dementia patients  .

TUESDAY, April 22 (HealthDay News) -- The Medicare Part D benefit has resulted in some improvements for seniors but no real revolution in prescription drug adherence.

A new report finds that Medicare beneficiaries are less likely to forego basic needs such as food to pay for medicine, but the sickest patients are still skipping meds due to burdensome costs.

"It's a mixed picture. We saw some things to be happy about and others to be concerned about," said study author Jeanne Madden, an instructor in the department of ambulatory care and prevention at Harvard Medical School in Boston. "Although this is the third year [of the program], the good data is just starting to come to the surface. It bears a lot of additional scrutiny."

Madden's study is in the April 23/30 issue of the Journal of the American Medical Association.

"This study reveals that the federal government has more work to do to assure that the Medicare Part D program meets the needs of the most vulnerable Medicare beneficiaries," Gail Shearer, director of health policy analysis at Consumers Union, said in a statement. "It is unacceptable that the sickest beneficiaries may not be filling prescriptions or taking the full doses or courses of their medicines because they simply can't afford to."

Medicare Part D, which provides drug benefits, took effect in January 2006. More than half of Medicare beneficiaries have enrolled in the program. Some 10 percent of beneficiaries still have no drug coverage, compared to up to 38 percent before the program took effect.

Surveys have shown that without adequate prescription drug benefits, seniors tend to skip doses, reduce doses or leave prescriptions unfilled. This, in turn, can result in serious health outcomes, including even heart attack and stroke.

Madden and her team looked at survey responses from 24,234 Medicare beneficiaries to determine how Medicare Part D had changed cost-related adherence to drug regimens.

In 2004 and 2005, before Part D, 15.2 percent and 14.1 percent of beneficiaries, respectively, skipped pills because of cost, versus 11.5 percent in 2006, after the program was implemented.

Similarly, in 2004 and 2005, 10.6 percent and 11.1 percent of beneficiaries, respectively, skimped on basic needs so as to be able to pay for medications, a percentage which declined to 7.6 percent in 2006.

The sickest individuals continued to skip pills at about the same rate both before and after Part D, although they were less likely to forego basic necessities. These beneficiaries are more likely to falling into the "donut hole," when drug costs are between $2,250 and $5,100, individuals have to pay the full cost of their drugs.

"This places a lot of burden on the sickest patients," Madden said. "[But] those sicker people aren't the only ones who are going to fall into the gap. The structure of that is pretty harsh. There's no coverage whatsoever for several thousand dollars."

A second study appearing in the same issue of the journal found that not only did Medicare beneficiaries enrolled in Part D still skip doses or switch to cheaper drugs, many do not understand the program.

The findings, conducted by researchers at Kaiser Permanente Medical Care Program in Oakland, Calif., were based on telephone interviews with about 1,000 Medicare beneficiaries in Northern California.

Only 40 percent of respondents knew that the new drug plan had a coverage gap (the "donut hole"). Thirty-six percent of respondents reported at least one cost-coping behavior. These behaviors were more common in households with lower incomes.

More information

Visit Consumer Reports   for a free guide to prescription drugs.