July 22, 2010, 7:34 AM CT

Chaos theory help predict heart attacks

Chaos models may someday help model cardiac arrhythmias -- abnormal electrical rhythms of the heart, say scientists in the journal CHAOS, which is published by the American Institute of Physics. In recent years, medical research has drawn more attention to chaos in cardiac dynamics. Eventhough chaos marks the disorder of a dynamical system, locating the origin of chaos and watching it develop might allow scientists to predict, and maybe even counteract, certain outcomes.

An important example is the chaotic behavior of ventricular fibrillation, a severely abnormal heart rhythm that is often life-threatening. One study found chaos in two and three dimensions in the breakup of spiral and scroll waves, believed to be precursors of cardiac fibrillation. Another study observed that one type of heartbeat irregularity, a sudden response of the heart to rapid beating called "spatially discordant alternans," leads to chaotic behavior and thus is a possible predictor of a fatal heart attack.

Mathematicians Shu Dai at Ohio State University and David Schaeffer at Duke University have built on this work to find another chaotic solution to an equation for alternans along a one-dimensional fiber of cardiac tissue with stimuli applied at one end. Assigning extreme parameter values to the model, the team was able to find chaotic behavior in space over time. The resulting chaos may have a unique origin, which has still not been identified. -- VC, En......... Posted by: Daniel      Read more         Source

July 21, 2010, 6:11 AM CT

Key pathway in end-stage prostate cancer blocked

Prostate cancer advances when tumors become resistant to hormone treatment, which is the standard therapy for patients, and begin producing their own androgens.

Scientists at UT Southwestern Medical Center have observed that blocking one of the enzymatic steps that allow the tumor to produce androgens could be the key in halting a tumor's growth.

The findings, appearing online and in the recent issue of Endocrinology, suggest that this step might one day provide a new avenue of treatment for patients with end-stage prostate cancer. Health care experts estimate that more than 2 million men in the U.S. have prostate cancer, with more than 27,000 deaths correlation to the disease in 2009.

"We were able to block the androgen response, which is a central pathway for tumor progression," said Dr. Nima Sharifi, assistant professor of internal medicine and the study's senior author.

End-stage prostate tumors typically are treated with hormones that suppress the levels of the androgens, or male hormones like testosterone, that cause prostate cancer cells to grow. Eventually, however, the tumors become resistant to this treatment and resume their growth.

Using prostate cancer cell lines, Dr. Sharifi and colleagues observed that the hormone dehydroepiandrosterone (DHEA) is converted by the tumors into androgens. By blocking the enzyme 3β-hydroxysteroid dehydrogenase (3βHSD), which is responsible for the first enzymatic step that is mandatory to convert DHEA to androgens, scientists were able to shut down the tumors' lifeline......... Posted by: Mark      Read more         Source

July 21, 2010, 6:10 AM CT

Children's school performance tied to family "type"

The way a family interacts can have more of an impact on a child's predicted school success than reading, writing or arithmetic, as per a University of Notre Dame study published recently in the Journal of Child Development.

University of Notre Dame Professor of Psychology Mark Cummings and his colleagues at the University of Rochester studied the relationship patterns of some 300 families (with six year-olds) over the course of three years, and found distinct family-school connections. Specific family "types" emerged as predictors of school success:

"Coming from a cohesive family, in which members tend to be warm and responsive to one another, where problems are resolved, and members cope well, increases the likelihood of children doing well in school," as per Cummings.

Children from enmeshed families, characterized by over involvement, hostility and only moderate warmth, enter school with no more problems than their cohesive family peers, but suffer more anxiety and feelings of alienation later, Cummings explains.

The third family type, "detached," in which all problems are avoided, in which hostility is present, and without displays of affection, tend to have children with the most problems.

"They often start school with more disruptive behavior and higher levels of aggression and difficulty cooperating," Cummings explains......... Posted by: JoAnn      Read more         Source

July 21, 2010, 6:08 AM CT

Protection against ticks that carry Lyme disease

Research on the population of black-legged ticks, which can transmit Lyme disease from host animals to humans, reinforces that it is important to take preventative measures when spending time outdoors.

University of Illinois graduate student Jennifer Rydzewski conducted a four-year survey of black-legged ticks (also known as deer ticks), their host animals, and their habitat preferences in Cook, Lake, DuPage, and Piatt Counties. The survey confirmed the presence of ticks in all four counties and ticks carrying Lyme disease in Piatt County. Higher numbers of ticks were found along the Des Plaines River corridor.

"Their small size makes ticks really difficult to see. They're about the size of a poppy seed," Rydzewski said.

"Ticks in the nymph stage of their life cycle are responsible for the most human cases of Lyme disease because their peak seasonal activity coincides with increased human activity outdoors during the warmer summer months, so it's important for people to take extra precautions."

In humans, early symptoms of Lyme disease are often nondescript, flu-like symptoms such as fever, headache, and fatigue, making it difficult to diagnose from symptoms alone. In about 70 percent of the cases, people will develop the typical bullseye-shaped rash linked to Lyme disease. If it's caught in the early stages it can be treated with broad-spectrum antibiotics; however, if it's not treated early, the result can be long-term severe joint pain, arthritis and neurological damage. The disease is named after the town of Lyme, Connecticut, where many cases were identified in 1975......... Posted by: Mark      Read more         Source

July 21, 2010, 6:05 AM CT

Depression overlooked in patients with hepatitis C

Scientists from Denmark, Sweden, Norway and Finland (the NORDynamIC project group) have found that depressive symptoms in patients with hepatitis C virus (HCV) infection are usually overlooked in routine clinical interviews, and that therapy-induced depression compromises the outcome of HCV treatment. A second U.S. study observed that patients with chronic infection had lower (work) productivity and incurred higher medical benefit costs than those without HCV. Both studies are available in the recent issue of Hepatology, a journal published by Wiley-Blackwell on behalf of the American Association for the Study of Liver Diseases (AASLD).

HCV is a blood-born infection causing inflammation and destruction of liver cells. When inflammation lasts longer than six months there is ongoing liver cell injury which is defined as chronic HCV. The standard therapy protocol for chronic HCV is weekly injections of peg-interferon alfa-2a in combination with daily oral ribavirin for 24 to 48 weeks. However, this combination therapy can lead to major depression or other psychiatric complications in many HCV patients which may require premature termination of the antiviral treatment.

Peter Leutscher, M.D., Ph.D., and his colleagues estimated the value of routine medical interviews in diagnosing depression in chronic HCV patients receiving peg-interferon/ribavirin treatment using the Major Depression Inventory (MDI). The MDI is a self-rating depression scale with a dual functionality in diagnosing major depression and in measurement of depression severity. Of the 325 HCV patients enrolled in the study, 6% were observed with major depression at baseline. Among the remaining 306 patients, 37% (n=114) developed depression while on HCV combination treatment. "As per the MDI criteria, we observed that only 32% of the 114 patients with major depression were correctly diagnosed during routine medical interviews," noted Dr. Leutscher......... Posted by: JoAnn      Read more         Source

July 16, 2010, 7:20 AM CT

Behavior Problems in School

Contrary to Leo Tolstoy's famous observation that "happy families are all alike; every unhappy family is unhappy in its own way," a new psychology study confirms that unhappy families, in fact, are unhappy in two distinct ways. And these dual patterns of unhealthy family relationships lead to a host of specific difficulties for children during their early school years.

"Families can be a support and resource for children as they enter school, or they can be a source of stress, distraction, and maladaptive behavior," says Melissa Sturge-Apple, the lead researcher on the paper and an assistant professor of psychology at the University of Rochester.

"This study shows that cold and controlling family environments are associated with a growing cascade of difficulties for children in their first three years of school, from aggressive and disruptive behavior to depression and alienation," Sturge-Apple explains. "The study also finds that children from families marked by high levels of conflict and intrusive parenting increasingly struggle with anxiety and social withdrawal as they navigate their early school years."

The three-year study, published July 15 in Child Development, examines relationship patterns in 234 families with six-year-old children. The research team identified three distinct family profiles: one happy, termed cohesive, and two unhappy, termed disengaged and enmeshed......... Posted by: JoAnn      Read more         Source

July 16, 2010, 7:07 AM CT

Not Getting Enough vitamin D

Vitamin D surfaces as a news topic every few months. How much daily vitamin D should a person get? Is it possible to have too much of it? Is exposure to the sun, which is the body's natural way of producing vitamin D, the best option? Or do supplements suffice?.

In the July 2010 issue of Endocrine Today, a monthly newspaper published by SLACK, Inc., to disseminate information about diabetes and endocrine disorders, Anthony Norman, a distinguished professor emeritus of biochemistry and biomedical sciences and an international expert on vitamin D, notes that half the people in North America and Western Europe get insufficient amounts of vitamin D.

"Elsewhere, it is worse," he says, "given that two-thirds of the people are vitamin D-insufficient or deficient. It is clear that merely eating vitamin D-rich foods is not adequate to solve the problem for most adults." .

Currently, the recommended daily intake of vitamin D is 200 international units (IU) for people up to 50 years old; 400 IU for people 51 to 70 years old; and 600 IU for people over 70 years old.

"There is a wide consensus among researchers that the relative daily intake of vitamin D should be increased to 2,000 to 4,000 IU for most adults," Norman says. "A 2000 IU daily intake can be achieved by a combination of sunshine, food, supplements, and possibly even limited tanning exposure"......... Posted by: Janet      Read more         Source

July 14, 2010, 7:46 AM CT

Common medications may cause cognitive impairment

Drugs commonly taken for a variety of common medical conditions including insomnia, allergies, or incontinence negatively affect the brain causing long term cognitive impairment in older African-Americans, according to a study appearing in the July 13, 2010 print issue of Neurology, the medical journal of the American Academy of Neurology.

These drugs, called anticholinergics, block acetylcholine, a nervous system neurotransmitter, and are widely-used medical therapies. They are sold over the counter under various brand names such as Benadryl, Dramamine, Excedrin PM, Nytol, Sominex, Tylenol PM, and Unisom. Other anticholinergic drugs, such as Paxil, Detrol, Demerol and Elavil are available only by prescription. Older adults most commonly use drugs with anticholinergic effects as sleep aids and to relieve bladder leakage problems.

Researchers from Indiana University School of Medicine, the Regenstrief Institute and Wishard Health Services conducted a six-year observational study, evaluating 1,652 Indianapolis area African-Americans over the age of 70 who had normal cognitive function when the study began. In addition to monitoring cognition, the scientists tracked all over-the-counter and prescription medications taken by study participants.

"We found that taking one anticholinergic significantly increased an individual's risk of developing mild cognitive impairment and taking two of these drugs doubled this risk. This is very significant in a population African-Americans already known to be at high risk for developing cognitive impairment," said Noll Campbell, PharmD, first author of the study. Dr. Campbell is a clinical pharmacist with Wishard Health Services......... Posted by: Janet      Read more         Source

July 14, 2010, 7:43 AM CT

Superstition Might Improve Performance

Don't scoff at those lucky rabbit feet. New research shows that having some kind of lucky token can actually improve your performance - by increasing your self-confidence.

"I watch a lot of sports, and I read about sports, and I noticed that very often athletes - also famous athletes - hold superstitions," says Lysann Damisch of the University of Cologne. Michael Jordan wore his college team shorts underneath his NBA uniform for good luck; Tiger Woods wears a red shirt on tournament Sundays, commonly the last and most important day of a tournament. "And I was wondering, why are they doing so?" Damisch thought that a belief in superstition might help people do better by improving their confidence. With her colleagues Barbara Stoberock and Thomas Mussweiler, also of the University of Cologne, she designed a set of experiments to see if activating people's superstitious beliefs would improve their performance on a task.

In one of the experiments, volunteers were told to bring a lucky charm with them. Then the scientists took it away to take a picture. People brought in all kinds of items, from old stuffed animals to wedding rings to lucky stones. Half of the volunteers were given their charm back before the test started; the other half were told there was a problem with the camera equipment and they would get it back later. Volunteers who had their lucky charm did better at a memory game on the computer, and other tests showed that this difference was because they felt more confident. They also set higher goals for themselves. Just wishing someone good luck - with "I press the thumbs for you," the German version of crossing your fingers - improved volunteers' success at a task that mandatory manual dexterity. The research is published in Psychological Science, a journal of the Association for Psychological Science......... Posted by: JoAnn      Read more         Source

July 14, 2010, 7:24 AM CT

Interferon for asthma

An immune-system protein already used to treat diseases like multiple sclerosis, hepatitis C and a variety of cancers might also aid asthma patients, UT Southwestern Medical Center scientists have found.

The researchers determined that the protein interferon blocks the development of a population of immune cells known to cause asthma. These cells are members of a class of T lymphocytes, called T helper 2 cells, or Th2 cells. Under normal circumstances, Th2 cells help protect against infections by secreting chemicals that induce inflammation; however, in some individuals, these Th2 cells can also promote allergic responses to normally harmless substances, including animal dander, pollens and pollutants. Once Th2 cells become reactive to these substances, they promote all of the inflammatory processes common to allergic diseases like asthma and atopic dermatitis.

The findings, available online and in the July 15 issue of the Journal of Immunology, suggest that interferon might be a valuable and readily available treatment for individuals with asthma.

"This finding is incredibly important, because humans are being treated with interferon for a variety of diseases, yet no one has tried treating asthma patients with interferon," said Dr. J. David Farrar, assistant professor of immunology and molecular biology at UT Southwestern and senior author of the study. "The current therapies for asthma are inhalers and steroids, both of which offer only temporary relief."........ Posted by: JoAnn      Read more         Source