Risk factors for sudden death for adult muscular dystrophy identified

The largest assessment of people with adult muscular dystrophy has identified risk factors that can lead to sudden death for individuals with the most common form of this disease.

The results of the multicenter study, lead by the Indiana University School of Medicine, are reported in the June 19 issue of the New England Journal of Medicine.

Neurologists and cardiologists at 23 neuromuscular disease clinics nationwide affiliated with the Muscular Dystrophy Association assessed 406 adult patients with myotonic dystrophy type 1 using clinical history, genetic assessment and electrocardiograms (ECG) to determine the risk factors that cause arrhythmias and sudden cardiac death.

"The study has prospectively identified risk factors that predict a high risk of sudden death in people with myotonic dystrophy, the most common form of muscular dystrophy that we see in adults," said the study's principal investigator and lead author William J. Groh, M.D., M.P.H., associate professor of medicine at the Indiana University School of Medicine and the Krannert Institute of Cardiology. Sudden death is defined as a death that occurs in a stable patient within one hour of the onset of symptoms.

During the 10 years of the study, 20 percent of the people enrolled died, said Dr. Groh. Of those, one-third died of sudden death likely attributable to cardiac arrhythmia.

"Patients who had significant abnormalities on their ECG were at a 3.5 times higher risk of sudden death," said Dr. Groh. "Those with atrial (upper) chamber arrthymias had a 5 times higher risk."

In the future, physicians can use these risk factors to evaluate patients with myotonic dystrophy to hopefully prevent sudden death through further evaluation including electrophysiological studies (using catheters in the heart) or by surgically implanting a cardioverter-defibrillator.

Dr. Groh said another important outcome of the study was the discovery that pacemakers, commonly used to treat some forms of arrhythmia, did not help these patients prevent sudden death.

Myotonic muscular dystrophy, an inherited disease, is characterized primarily by progressive muscle weakness and muscle wasting. It affects approximately 1 of every 8,000 people in the United States.

In many muscular dystrophies, the heart muscle is adversely affected. Those heart abnormalities can be as serious and debilitating as the skeletal muscle involvement more commonly associated with muscular dystrophy.

This study was funded by Medtronic, the Muscular Dystrophy Association and the National Institutes of Health.

http://www.iupui.edu

How best to treat chronic pain? The jury is still out

How best to alleviate chronic pain, a leading cause of disability and employee absenteeism, continues to perplex both patients and their doctors.

A review of recent studies on pain medicine appearing in the June 2008 issue of the Journal of General Internal Medicine reports that while various approaches and combinations of therapies to treat pain have advantages and disadvantages, researchers don't yet know how to determine which is best for individual patients.

Among the approaches to pain management studied were those relying on the prescription of opioids (drugs such as morphine, Percocet and Vicodin), surgery, and alternative medicine (acupuncture, herbal remedies).

"We conducted this review of pain management strategies because doctors, especially primary care doctors who manage the bulk of patients with chronic pain, are frustrated and want to know how to better alleviate what is often debilitating pain. Many of these physicians have not been well trained in pain management. And while many are paying more attention to pain than ever before, especially given JCAHO (Joint Commission on Accreditation of Healthcare Organizations) and Veteran Affairs mandates that pain be regarded as the 'fifth vital sign,' they don't know what treatment will work for a given patient. They want guidance and we found very limited information," said the paper's senior author, Matthew J. Bair, M.D. Dr. Bair is an assistant professor of medicine at the Indiana University School of Medicine, a research scientist with the Regenstrief Institute, Inc. and an investigator at the Roudebush VA Center of Excellence for Implementing Evidence Based Practice.

Chronic or recurrent pain affects more than 75 million Americans.

"We have found that there are huge gaps in our knowledge base. For example, none of the opioid research trials lasted longer than four months, a small fraction of the time during which many chronic sufferers typically experience pain and are prescribed this potent class of medication," said Dr. Bair. "Similarly there were insufficient trials of herbal remedies versus other analgesics (i.e. pain medicines), in spite of the fact that pain management is one of the major reasons for the use of alternative medicine."

Dr. Bair's own research focuses on understanding the interface between affective disorders such as depression and anxiety and chronic pain and developing strategies to improve pain management in the primary care setting.

http://www.iupui.edu

Saving teeth by using periodontal ligament regeneration

Teeth may fall out as a result of inflammation and subsequent destruction of the tissues supporting the teeth. Dutch researcher Agnes Berendsen has investigated a possible solution to this problem. At the Academic Centre for Dentistry Amsterdam (ACTA), she has studied the regeneration of the periodontal ligament by use of tissue engineering.

The 3D in vitro model she has developed appears to be promising for regenerating periodontal ligament and may also prove valuable for restoring tendons and ligaments elsewhere in the body.

The periodontal ligament forms a flexible connection between the tooth root and the surrounding jaw bone. Trauma or inflammation can cause destruction of the periodontal ligament. Berendsen chose tissue engineering to tackle this problem. Research in tissue engineering uses cells placed in a 3D model, after which signals are applied to activate the cells. Berendsen developed a new 3D model in which cells isolated from periodontal ligament were implanted in a collagen network suspended between an artificial root and artificial bone. She wanted to see if viable periodontal ligament could be generated in this way.

The composition of the collagen network in which the cells are located has a considerable influence on the contractile properties of the cells. Contraction of the cells creates internal tension in the network which keeps the cells active. The network must be well attached to the surrounding solid surfaces to prevent its detachment. Berendsen managed to attach the network to these artificial root and bone surfaces present in the model by creating an enzyme-mediated mineral deposition on the surfaces. By subsequently applying loading to the tooth root (mimicking the process of chewing) in the 3D model, she was able to deform the mineral-anchored network containing the cells. The subsequent response of the cells was dependent on the magnitude of the loading.

Follow-up research will investigate whether the cell-culture results can be translated to an animal model to obtain more accurate insights concerning the potential use of this method in humans.

http://www.nwo.nl/

Happy children may not be best learners

Psychologists at the University of Virginia and the University of Plymouth (UK) have conducted experimental research that contrasts with the belief that happy children are the best learners.

The findings, which currently appear online in the journal Developmental Science and will be printed in the June issue, show that where attention to detail is required, happy children may be at a disadvantage.

The researchers conducted a series of experiments with different child age groups who had happy or sad moods induced with the aid of music (Mozart and Mahler) and selected video clips (Jungle Book and the Lion King). The groups were then asked to undertake a task that required attention to detail - to observe a detailed image such as a house and a simple shape such as a triangle, and then locate the shape within the larger picture. The findings in each experiment with both music and video clips were conclusive, with the children induced to feel a sad or neutral mood performing the task better than those induced to feel a happy state of mind.

Lead researcher Simone Schnall of the University of Plymouth describes the psychology behind the findings: "Happiness indicates that things are going well, which leads to a global, top-down style of information processing. Sadness indicates that something is amiss, triggering detail-orientated, analytical processing.

"However, it is important to emphasize that existing research shows there are contexts in which a positive mood is beneficial for a child, such as when a task calls for creative thinking. But this particular research demonstrates that when attention to detail is required, it may do more harm than good."

Co-author Vikram Jaswal, an assistant professor of psychology at the University of Virginia, added that the findings contradict conventional wisdom that happiness always leads to optimal outcomes. "The good feeling that accompanies happiness comes at a hidden cost. It leads to a particular style of thinking that is suited for some types of situations, but not others."

http://www.virginia.edu/