TUESDAY, Jan. 8 (HealthDay News) -- Americans living in small towns and rural areas are less likely to get organ transplants or be placed on waiting lists for transplants, a new study found.

The study of almost 175,000 potential transplant recipients showed that those living outside metropolitan centers "were 8 percent to 15 percent less likely to be wait-listed and 10 percent to 20 percent less likely to undergo heart, liver and kidney transplantation than patients in urban environments," the report said.

The report suggested two possible explanations for the findings: different patterns of illness in rural areas, or the difficulty of getting on a transplant list.

The second factor is probably more significant, transplant experts said.

"You can't just get listed easily," said Dr. Pang-Yen Fan, director of kidney transplantation at the University of Massachusetts Memorial Medical Center in Worcester. "It requires both medical and surgical evaluation, lots of testing, visits to a transplant center. Many of the patients we see live in a 30- to 50-mile radius of Worcester. For them, coming into Worcester is a big deal. So I don't think the results of the study are surprising."

Lack of sophistication on the part of potential transplant patients and their doctors also plays a role, said Dr. John Fung, director of transplant services at the Cleveland Clinic.

"You can look at the demographics of the [U.S.] population," Fung said. "Fifty percent of the people in metropolitan areas have a high school education or better, compared to one third in rural areas. So there can be a lack of knowledge."

The study, conducted by a group led by Dr. David A. Axelrod, assistant professor of surgery at Dartmouth Medical School in Lebanon, N.H., is published in the Jan. 9/16 issue of the Journal of the American Medical Association.

Organ transplants are often the best last hope for patients with heart, liver and kidney disease. Previous research has uncovered barriers to transplants for racial minorities, women, and patients who are poor or lack adequate health insurance, according to background information for the new study.

The new study looked at a number of factors that might affect the transplant rate but did not include education, Fung said. "Many people are not aware that a transplant is an option for them," he said. And doctors in rural areas might also not raise the possibility of a transplant, he added.

Distance is also a factor, Fung said. "If you look at the number of transplant programs, there are about 200 for kidney, 150 for heart, 100 for liver," he said. "So not every metropolitan area has a transplant program. The closer you live to a transplant program, the more likely you are to have one."

Another issue is the number of transplant centers in the United States, said Fan, who also is chairman of the United Network for Organ Sharing minority affairs committee. "It's important to have an adequate distribution of transplant centers around the country," he said. "And when you look at centers, you should not just be looking at their numbers. A center may do an important service even if it does only 20 to 30 transplants a year."

But opening more centers is not the answer, Fung said. "Quality is volume-dependent," he said. "The more of these you do, the better the results you get."

In the end, it's important for rural residents and their physicians to be aware that transplantation is an option in many cases and to take the necessary steps to be put on a waiting list, Fan said.

"Once you are on the list, you no longer are at a major disadvantage to anyone in an urban area," he said.

More information

Detailed information about transplants is available from the United Network for Organ Sharing  .

FRIDAY, Jan. 4 (HealthDay News) -- Researchers have verified what many American drivers already knew: Drivers who talk on a cell phone clog traffic.

These highway conversationalists drive slower on the freeway, pass slower vehicles less often and take longer to complete their trip compared to the cell phone-free, reports a new study.

A fatal accident can cost up to $5 million in medical, property and loss-of-income costs, but these types of events occur much less often than everyday traffic delays, the researchers noted.

Traffic delays linked to cell phone use are estimated to cost about $13 per hour -- based on a measure of the value of a typical American traveler's time. Multiply $13 by the millions of drivers every day who talk, argue, yell and conduct meetings on the phone, and the figures add up, the researchers said.

Highway officials know that all too well.

"Safety on the roads is our number one priority," said Doug Hecox, a spokesman for the Federal Highway Administration, part of the Department of Transportation. "We cannot equivocally say that using a cell phone while driving is a distraction but we are doing everything we can to reduce distractions, which can include loud radios and kids in the back seat. When the driver is in charge of a vehicle, it is a serious operation."

The study was led by Joel Cooper, a doctoral student in psychology at the University of Utah, who will be presenting the findings Jan. 16 at the Transportation Research Board's annual meeting in Washington, D.C.

According to background information in the study, more than 240 million people now use wireless services in the United States, and an estimated 73 percent of them admit to using their phones while driving. One survey found that about 10 percent of drivers were using wireless phones at any daylight moment in 2005.

Previous studies have found that drivers talking on cell phones are up to four times as likely to be involved in an accident, the same risk as driving while drunk.

Fifty countries now have laws prohibiting the use of cell phones while driving, unless those phones are hands-free. Even then, the research isn't clear that hands-free devices help reduce driver distraction.

Earlier studies have found that cell phone users follow other cars at greater distances, are slower to hit the brakes and slower to regain speed after braking.

For this study, 36 University of Utah psychology undergraduate students used a PatrolSim driving simulator, built to mimic a Ford Crown Victoria sedan with automatic transmission. Different traffic scenarios appeared on three screens around the driver.

Each participant drove through six, 9.2-mile-long stretches of highway: two each in low-, medium- and high-density traffic with freeway speeds of 70 mph to 40 mph. One ride at each density level was done while talking on a cell phone and one while not using a cell phone.

"We found that when drivers were conversing on the cell phone, they drove those sections about two miles per hour slower when traffic density was medium or high," Cooper reported. "In all three scenarios, when people were talking on the cell phone, they made about 20 percent fewer lane changes."

Cell phone talkers took 15 seconds to 19 seconds longer to complete the distance assigned, and they also took 17 percent more time to recover half of their speed after braking. Motorists on cell phones also tended to trail other cars rather than overtake and pass them, potentially adding to traffic slowdowns.

All of this came from a simulation involving only one person talking on the phone.

"The next step is to take these, plug them into the microsimulator and try to make some more concrete generalizations about broad traffic flow," Cooper said.

More information

There's more on driving and cell phones at the National Safety Council  .

FRIDAY, Jan. 4 (HealthDay News) -- The nerve cell death that helps drive Parkinson's disease may be triggered by a harmful modification in a particular nerve cell protein, new research reveals.

The modification in question -- an apparently toxic mix of the protein alpha-synuclein and the critical neurotransmitter dopamine -- can be found in all Parkinson's patients, researchers say.

The change short-circuits a process that allows aging nerve cells to stay healthy by purging themselves of damaged molecules, researchers explain in the Jan. 2 online issue of The Journal of Clinical Investigation.

"The general idea is that, in Parkinson's, the neurons accumulate lots of garbage," explained study author Dr. Ana Maria Cuervo, an associate professor in the department of anatomy and structural biology at Yeshiva University's Albert Einstein College of Medicine, in New York City.

"Normally," she said, "this garbage is removed before it builds up, and is dumped into garbage containers called lysosomes, which make sure things can move about the neurons fast and freely."

Such a filtering process for disposing of damaged molecules is known as "autophagy," a term that literally means "self-eating."

"But sometimes, this mechanism fails," Cuervo noted. "And now we have found the reason why. It is because of the formation of this particular modified protein, which acts kind of like chewing gum in the middle of the nerve cell."

"It's not a normal protein," she stressed. "It's very sticky, and any other proteins passing by get stuck to it, so you get all these abnormal things, these stones in the middle of the cell's highways, that are not being removed, and eventually the [brain] cells can't move things around as they should, and they die."

In an earlier effort, the same research team had found that mutant forms of alpha-synuclein -- as opposed to modified forms -- also block the desired breakdown of damaged nerve cell molecules. Such mutant proteins are present in the 5 percent to 10 percent of Parkinson's patients struck with a relatively rare, familial form of the disease.

"But the novelty of our work today is that the modified protein mechanism we found this time will apply to all Parkinson's patients," noted Cuervo. "And so it becomes possible that in the future we can design drugs to improve the function of the garbage containers, the lysosomes, in all Parkinson's patients, and maybe overcome the problem that these nerve cells have handling the modified molecules."

Cuervo and her Einstein colleagues conducted the study, based on laboratory work with male rats, in collaboration with scientists from Columbia University in New York City, the University of Pennsylvania, and Harvard Medical School in Boston.

The National Parkinson Foundation estimates that 1.5 million Americans are affected with Parkinson's disease, the most common degenerative brain disorder affecting movement.

The nerve damage that's characteristic of this incurable disease brings about a dramatic loss of muscle control, typically manifesting as tremors, stiffness, and a loss of balance and agility.

Though optimistic about her work, Cuervo emphasized that translating the latest findings into new preventive and curative interventions will require a lot more research and time.

"I want to be very cautious," she said. "We are far from a final cure. It's not something we can do tomorrow. It's going to take some time. But now we know what the problem is. And we think that we have something, a target, to focus on."

Nonetheless, Dr. Robert Burke, director of the Morris K. Udall Parkinson's Disease Research Center of Excellence at Columbia University, called the new findings a "big step forward."

"Their first finding was only related to the mutant form of the protein which is very rare," he noted. "Whereas here they have shown that dopamine-modified neurons also block the system. This means they now have something that appears applicable to patients with the much more common sporadic form of Parkinson's. And that is very, very helpful."

More information

For more on Parkinson's disease, head to the Parkinson's Disease Foundation  .

FRIDAY, Dec. 21 (HealthDay News) -- Developmental problems involving a walnut-shaped part of the brain called the amygdala -- linked to fear, anxiety and other emotions -- may explain why mental illness and addiction often appear together, researchers say.

Many kinds of addiction -- such as those for alcohol, drugs and nicotine -- occur in people with various kinds of mental illness, including depression, schizophrenia and anxiety disorders, according to background information in an American Psychological Association news release about the Indiana University study.

Two to five of every 10 anxious or depressed people, and four to eight of every 10 people with schizophrenia, biopolar disorder or antisocial personality, also have some form of addiction, according to epidemiological data.

In this study, published in the December issue of Behavioral Neuroscience, the researchers compared the behavior of adult rats whose amygdalas were surgically damaged in infancy and adult rats with intact amygdalas.

Rats with the damaged amygdalas showed less fear and caution than normal and were significantly more sensitive to cocaine after just one exposure to the drug. Rats with damaged amygdalas that received repeated cocaine injections developed "even stronger expressions of the enduring changes in behavior -- suggesting an overall hypersensitivity to the addictive process," the researchers noted.

Since both groups of rats were raised in the same controlled conditions, the damaged amygdala was the likely cause of the impaired fear behavior, as well as the heightened drug response, in the one group of rats, the study authors concluded.

In humans, disease and interactions between genetic and environmental factors can alter amygdala function or change the way it's connected to the rest of the brain during childhood and adolescence.

"Early emotional trauma, paired with a certain genetic background, may alter the early development of neural networks intrinsic to the amygdala, resulting in a cascade of brain effects and functional changes that present in adulthood as a dual-diagnosis disorder," lead author Dr. Andrew Chambers explained in a prepared statement.

More information

The (U.S.) National Alliance on Mental Illness has more about dual diagnosis of substance abuse and mental illness  .