From Newswise Medical News |

People who are easily distressed and have more negative emotions are more likely to develop memory problems than more easygoing people, according to a new study.

In the study, those who most often experience negative emotions such as depression and anxiety were 40 percent more likely to develop mild cognitive impairment than those who were least prone to negative emotions. Mild cognitive impairment is a transitional stage between normal aging and dementia. People with mild cognitive impairment have mild memory or cognitive problems, but have no significant disability.

Researchers analyzed the results from two larger studies, the Religious Orders Study and the Memory and Aging Project, which involved 1,256 people with no cognitive impairment. During up to 12 years of follow-up, 482 people developed mild cognitive impairment. Participants were evaluated on their level of proneness to distress and negative emotions by rating their level of agreement with statements such as “I am not a worrier,” “I often feel tense and jittery,” and “I often get angry at the way people treat me.”

“People differ in how they tend to experience and deal with negative emotions and psychological distress, and the way people respond tends to stay the same throughout their adult lives,” said study author Robert S. Wilson, PhD, of Rush University Medical Center in Chicago, IL. “These findings suggest that, over a lifetime, chronic experience of stress affects the area of the brain that governs stress response. Unfortunately, that part of the brain also regulates memory.”

An earlier study by Wilson and his colleagues showed that people who are easily distressed are more likely to develop Alzheimer’s disease than more easygoing people.

Wilson said several factors lead researchers to believe that proneness to stress is a risk factor for memory problems and not an early sign of disease. For example, while the level of distress does not appear to increase in old age, the changes in the brain related to memory problems and Alzheimer’s disease do increase with age.

This research was published in the June 12, 2007, issue of Neurology, the scientific journal of the American Academy of Neurology. The study was supported by grants from the National Institute on Aging and the Illinois Department of Public Health.

From USATODAY.com

Scientists have inched closer to one day developing a drug that will extend the human life span.

They’re still not close, mind you, but closer. At least that’s the message in a study of the humble roundworm that tackles the mystery behind the only scientifically verified way for creatures to live longer: calorie restriction.

Scientists have long known that in many species, cutting back on calories leads to longer life. Studies have shown that eating 70% of the calories normally consumed, while also consuming adequate vitamins and other nutrients, extends the life of everything from simple yeasts to mice by about 40%.

But scientists haven’t known why this happens

whether through improved immune systems, less heart disease or better-working hormones

and whether it works in people as well.

In a study published in the journal Nature, Nicholas Bishop and Leonard Guarente of Massachusetts Institute of Technology in Cambridge report the discovery of a brain center in roundworms that seems to answer the “how it works” part of the puzzle.

The roundworm is one of the species that has been shown to get the longevity benefit from caloric restriction. The researchers found that a gene called skn-1b seems essential. People have forms of this gene, which is thought to play a role in skin formation and remove damaging chemicals from the bloodstream later in life. In roundworms, the gene seems to manifest in the brain through two neurons, or brain cells, called the ASI.

To confirm the neurons’ role in translating diet restrictions into longevity, the scientists used a laser microbeam to kill the cells. Their destruction “completely suppressed” the longevity response, they conclude, meaning that fewer calories no longer meant longer life.

To double-check, they inserted a gene that turns fluorescent into a fresh batch of roundworms. That fluorescent gene allowed scientists to see the neurons at work because it lit up when the skn-1b gene was turned on. As expected, the researchers saw the neurons glow brightly when the worms were subjected to caloric restriction and received the longevity benefit.

The researchers also found that at least 15 hormones, including the insulin released in response to eating, are released in cascades by the skn-1b gene. They believe the hormone signal may be what extends the life of the roundworms.

“It’s an intriguing study. It will lead to a whole lot more experiments,” says biochemist Brian Kennedy of the University of Washington in Seattle. The key news is the suggestion that it’s not just the amount of food but the brain’s awareness of food intake that is responsible for the beneficial effects. “That’s a new way to think about calorie restriction,” Kennedy says.

Scientists have been researching the calorie/longevity link since the 1930s, when researchers at Cornell University in Ithaca, N.Y., showed that rats on a low-calorie diet live twice as long as their normal-diet brethren.

Testing the idea on humans hasn’t yet proven a definite link to longer life. Researchers at Washington University in St. Louis reported last year that volunteers in one longevity-diet study had cardiovascular systems that were much healthier than normal, with 55-year-old study participants reporting blood pressure readings more typical of 20-year-olds. Study volunteers ate as little as 1,400 calories a day, rather than the 2,000 or more calories in a typical adult diet.

A related study in Nature, led by Andrew Dillin of the Salk Institute for Biological Studies in La Jolla, Calif., finds that a compound called PH-4, which quiets or increases gene activity, also plays a role in releasing the benefits of caloric restriction in roundworms.

So, good news for roundworms. But what about us mammals? Researchers including Guarente (who, like a lot of longevity researchers, is a founder and stockholder in a firm looking to someday sell longevity treatments), have found that the genes involved in caloric restriction are highly “conserved.” Conserved genes turn up in slightly altered forms in animals, ranging from primitive creatures, such as yeasts, to complex ones, such as mammals. Researchers suppose that from an evolutionary standpoint, longevity from caloric restriction allowed animals to survive periods of famine. So the genes remain in the genomes of creatures over the long haul.

For us pill-popping humans, researchers say the goal is to create a drug over the next decades that mimics the hormonal cascade or fools a mammalian brain center into facilitating longevity.

“I wouldn’t say it is time for people to get excited about a magic pill,” Kennedy cautions. “But (this kind of research) is the only way we are going to find out how calorie restriction works.”

From New York Times

Advances in radiology have radically transformed medical practice, with CT scans and nuclear medicine exams providing physicians with the ability to quickly pinpoint internal bleeding, diagnose kidney stones or confirm appendicitis, assess thyroid function and identify and open blockages in the blood vessels to the heart.The downside is that Americans are being exposed to record amounts of ionizing radiation, the most energetic and potentially hazardous form of radiation.

According to a new study, the per-capita dose of ionizing radiation from clinical imaging exams in the United States increased almost 600 percent from 1980 to 2006. In the past, natural background radiation was the leading source of human exposure; that has been displaced by diagnostic imaging procedures, the authors said.This is an absolutely sentinel event, a wake-up call, said Dr. Fred A. Mettler Jr., principal investigator for the study, by the National Council on Radiation Protection. Medical exposure now dwarfs that of all other sources.

The study, financed by the federal government, is to be published by early next year. It found a particularly sharp rise in the number of CT scans

to 62 million in 2006, from 3 million in 1980. Though CTs make up only 12 percent of all medical radiation procedures, they deliver almost half of the estimated collective dose of radiation exposure in the United States.

A CTscan exposes patients to far more radiation than a standard X-ray, and multislice CT scanners deliver higher doses of radiation than single-slice scanners.

Nuclear medicine exams increased to 18.1 million in 2006, from 6.4 million in 1980. They represent almost a quarter of the estimated collective radiation dose, with cardiac studies making up most of the dose.X-rays have been classified as carcinogens by the World Health Organization, the Centers for Disease Control and Prevention and the National Institute of Environmental Health Sciences, because studies have shown that exposure causes leukemia and cancers of the thyroid, breast and lung.

Yet with the exception of mammography, scans remain largely unregulated. (The Food and Drug Administration regulates manufacturers of equipment but does not inspect facilities, which are licensed by states. Radiation doses for mammography are limited by federal law.) Radiation doses for the same procedure can vary drastically, as different machines in the hands of different practitioners deliver doses that vary by as much as a factor of 10, experts say.Radiologists say they do not want to scare people away from having scans and exams when necessary, but they want patients

as well as physicians

to carefully evaluate the benefits and risks of each scan or exam, make sure the procedure is appropriate and keep track of cumulative exposure levels. Full-body CT scans should be avoided unless there is a good medical reason.

Were not saying you shouldnt have X-rays or CT scans

theyre wonderful, theyve totally revolutionized the practice of medicine, said Dr. E. Stephen Amis Jr., a former president of the American College of Radiology who is chairman of radiology at Albert Einstein College of Medicine and Montefiore Medical Center in New York. But if you go into the emergency room with recurrent pain and get a CT scan every time you show up, thats not good. Use a little common sense.Studies of atomic bomb survivors in Japan found a statistically significant increase in cancer at high levels of exposure

50 millisieverts, or mSv, about 16 times the current annual average for Americans from medical exams. But that figure is controversial; it is not clear that lower levels of radiation exposure are safe. Nor would it be unusual for a patient to exceed this level, according to a recent paper from the American College of Radiology.

It is worth noting that many CT scans and nuclear medicine studies have effective dose estimates in the range of 10 to 25 mSv for a single study, and some patients have multiple studies; thus it would not be uncommon for a patients estimated exposure to exceed 50 mSv, the paper said, adding that the International Commission on Radiological Protections has reported that CT doses can indeed approach or exceed levels that have been shown to result in an increase in cancer.A single CT scan of the abdomen, body or spine can expose a patient to 10 mSv, according to the American College of Radiology patient information Web site (www.radiologyinfo.org, see Safety). Mammography, on the other hand, delivers only 0.7 mSv, and a bone-density scan is only 0.01 mSv.

There are several steps patients can take to protect themselves, and they should not be shy about asking questions, doctors and other experts say.They can always inquire of the referring physician, Is this test necessary?

said Richard Morin, chairman of the radiology colleges quality and safety committee, adding that exams are often done for reasons that are not quite appropriate.

Doctors should be familiar with the radiology college index of appropriateness criteria, which rates the imaging procedures for some 200 medical conditions. Dr. Morin suggests asking the doctor ordering the test about its rating for a given condition.Scores range from 1 to 9, he said, and if the number turns out to be 1 or 2, you should look for some other exam.

When undergoing a scan or exam, patients should try to use a facility accredited by the American College of Radiology. The accreditation, which is voluntary, means the machines are surveyed and calibrated to use the correct level of radiation and the technologists are certified. It also means the images are likely to be of higher quality, reducing the likelihood of having to repeat a procedure and suffer additional exposure.Research studies closely regulate and monitor radiation doses, so participating in a research study may provide some protection, Dr. Morin said. Hospitalized patients are also often scanned routinely once a day when they are very ill, he said, and its not unreasonable for someone to ask, Do I really need this exam every day?

Patients may also want to ask the radiologists or technicians whether the machines are routinely inspected by a medical physicist.

Women should tell the doctor or technician if they might be pregnant; generally, women, children and young people should try to avoid scans.If patients are given a CD of their scan, along with the interpretation, they should hold onto it, to avoid having to repeat a procedure. People who are undergoing multiple studies may want to keep a record tracking all the radiological procedures they have had, and inform their physicians of their history, said Dr. Amis, of Albert Einstein.

Patients should have a questioning demeanor when going in for any kind of health care, he said. Unfortunately, the majority do not.

From ScienceDaily

New research shows that just one session of exercise can prevent a primary symptom of type 2 diabetes by altering fat metabolism in muscle.

Researchers from the University of Michigan discovered that a session of aerobic exercise increases storage of fat in muscle, which actually improves insulin sensitivity. Low insulin sensitivity, or insulin resistance, is an impaired ability of the body to take up sugar from the blood, which can lead to high blood sugar and diabetes.

Jeffrey Horowitz, associate professor in the U-M Division of Kinesiology, and his former doctoral student, Simon Schenk, now a post-doctoral fellow at the University of California, San Diego, conducted the study, which appeared online May 17 in the Journal of Clinical Investigation.

“It’s long been known that exercise can greatly improve insulin sensitivity,” Horowitz said. “But how exercise improves insulin sensitivity in obesity, and how much exercise is necessary for this effect is not clear.”

Impaired insulin sensitivity is particularly a problem in obese people because of the excessive amount of fatty acids released from their body fat stores. This overabundance of fatty acids is taken up by tissues like muscle and liver where they interfere with the ability of insulin to regulate sugar metabolism.

In muscle cells, fatty acids can be burned for energy, and they also can be stored as intramuscular triglyceride, or IMTG. IMTG is a reservoir for fat storage, and high IMTG levels correlate with insulin resistance in obese people and those with type 2 diabetes. Partly because of this correlation, many researchers assumed IMTG is somehow involved in the development of insulin resistance. Yet, people who exercise regularly also have high IMTG levels, but they are actually very sensitive to insulin.

With that in mind, U-M researchers set out to test their novel hypothesis: that increasing the capacity for fat storage in muscle after one session of exercise can actually increase insulin sensitivity. They suspected that for several hours after exercise more fatty acids entering the muscle will be stored as IMTG, thus keeping them from turning into more harmful metabolites that are known to cause insulin resistance. Essentially, this means that exercise may cause you to store more fat in your muscles, but in doing so your insulin sensitivity improves.

Researchers studied eight lean female subjects and infused fat into their bloodstream to increase fatty acid to levels commonly found in obesity. The subjects were admitted to the hospital for this two-day procedure on two separate occasions. On the first day of one hospital stay, they exercised for 90 minutes at 75 percent of maximum heart-rate; on the other visit, they remained inactive.

With all other conditions being equal, researchers found that during the nonexercise visit, the fat infusion reduced insulin sensitivity to levels commonly found in obese people.

However, they found that during the exercise visit, not only did the exercise prevent the impairment in insulin sensitivity, but it increased insulin sensitivity by about 25 percent over their base levels. The researchers also found that the exercise session had diverted more fatty acids to be stored as IMTG than without exercise, and as a result fewer fatty acids were available to become the harmful metabolites known to impair insulin sensitivity.

“We believe this describes a primary mechanism for how exercise improves insulin sensitivity in obesity,” Horowitz said.

The study findings also highlight the important metabolic health benefits of a single exercise session.

“Some of the key health benefits of exercise are not related to improved fitness but instead, the residual effects from the most recent exercise sessions are most important,” he said.

If this is correct, then getting a regular so-called dose of exercise may be much more important than your level of physical fitness. How hard the exercise dose must be in order for an obese person to reap the benefits, and how long the effects last remains unknown. Horowitz and his research team are addressing these issues.

From Reuters.com

Growing old can be disheartening. But for people with diabetes, the aging process can be downright depressing. A University of Florida study published this week in the Archives of Internal Medicine reveals that older adults diagnosed with the type 2 form of the disease are twice as likely as their peers to suffer from depression.

An estimated 21 percent of seniors have the disease, according to the American Diabetes Association, and 1.5 million new cases are diagnosed each year. People with diabetes are at increased risk for developing heart disease and stroke, as well as kidney disease, blindness, dental disease and a host of other conditions.

The researchers say depression may be next on the list. Doctors have noticed for some time that it is more common among patients with the disease, but researchers have debated the cause-and-effect relationship for years. People with diabetes may suffer hormonal imbalances that predispose them to depression. On the other hand, depression is associated with physical and behavioral factors such as obesity and poor diet that some say could be enough to trigger diabetes in the elderly. The question of which ailment came first - diabetes or depression - has remained a mystery until now.

“This is the first study to evaluate diabetes as a risk factor for the onset of depression in older persons,” said study author Dr. Matteo Cesari, a geriatrician in UF’s Institute on Aging. “It’s likely we are looking at a vicious, self-feeding cycle: Diabetes causes depression, which may reduce adherence to diabetic treatment, therefore worsening the diabetic condition, and so on.”

The UF researchers evaluated 2,500 healthy patients aged 70 to 79 over a six-year period to determine if adult-onset diabetes is a risk factor for depression. The participants were enrolled in the Health, Aging and Body Composition (ABC) study, an ongoing program sponsored by the National Institute on Aging that is based in Memphis, Tenn., and Pittsburgh.

The researchers, in collaboration with Health ABC investigators at six other universities in the U.S. and Europe, discovered that people with diabetes are indeed twice as likely to suffer from recurrent depression later in life. The risk is slightly higher for those who don’t stick to recommended diet and treatment regimens.

About 23 percent of the study participants had diabetes, and nearly two-thirds of those patients had unhealthy blood sugar levels. The study also revealed that diabetics with high blood sugar also had elevated levels of an inflammatory marker called interleukin-6 that has been associated with depression.

“There may be a direct biological link between diabetes and depression,” said Dr. Marco Pahor, director of the University of Florida’s Institute on Aging and chairman of the College of Medicine’s department of aging and geriatrics. “We know that depression is linked to proinflammatory cytokines, for one. Diabetes may be one of the triggers that causes depression.”

Lack of exercise and an unhealthy diet appeared to be key factors that contribute to depression in people with diabetes, researchers found.

“Obesity and physical performance are the most important mediators in the relationship between diabetes and depression reported in the study,” Cesari said. “It is noteworthy that both are related to poor health status and poor quality of life.”

To avoid feeling melancholy later in life, the researcher team recommends that people with diabetes should take extra care to control their blood sugar levels by maintaining a healthy diet, exercising regularly and remembering to take prescribed medications.

“Diabetes is a preventable condition. Right now, we are facing a national epidemic because of obesity and a sedentary lifestyle,” Pahor said. “Inspiring a change in lifestyle is an important way that physicians can help patients avert depression and other complications of diabetes.”

Depression can be a slippery slope. Patients overwhelmed by sadness are more likely to abandon healthy eating habits and become less active, the researchers said. The study highlights the need for doctors to prevent the onset of diabetes by encouraging healthy decisions regarding diet, exercise and medication.

“If diabetes is already present, the careful monitoring of this condition and the control of (blood sugar) levels are particularly important to avoid future negative health-related events, including the potential onset of depression,” Cesari said.

Although physicians sometimes overlook depression in the elderly, the National Institute of Mental Health reports that the rate of suicide deaths in the older population exceeds that of the general population.

“The research showing that diabetes has an independent effect on the onset of new depression is an important finding,” said Dr. Jack Guralnik, chief of the laboratory of epidemiology, demography and biometry at the National Institute on Aging. “Physicians caring for older diabetic patients need to be particularly observant to identify the onset of depression so that they can initiate early treatment.“