June 1, 2006, 6:17 PM CT

How Brain Controls Movement

By training a group of human subjects to operate a robot-controlled joystick, Johns Hopkins scientists have shown that the slower the brain "learns" to control certain muscle movements, the more likely it is to remember the lesson over the long haul. The results, the researchers say, could alter rehabilitation approaches for people who have lost motor abilities to brain injuries like strokes.

In a report on the work in the May 23 issue of PLoS Biology, the scientists built on their observations that some parts of the brain learn - and forget - fast, while others learn more slowly and more lastingly. Both types of learning are critical.

"We believe our work is the first to show that motor learning involves different time scales and implies that the best strategy in rehabilitating a stroke patient should focus on slow learning because slow-learned motor skills will be maintained longer," says the report's senior author, Reza Shadmehr, Ph.D., a professor of biomedical engineering in the Institute of Basic Biomedical Sciences at Johns Hopkins.

Neuroresearchers long have thought that two things are mandatory for mastering such muscle control - time and error. Time refers to the need to "sleep on it," for the brain to somehow process and "remember" how to carefully control muscles. As for error, it's thought that mistakes help the brain and muscles fine-tune fine movements. The requirement for time and error explains why repetition of simple movements day after day is used routinely in rehabilitating partially paralyzed stroke patients and those with other brain injuries.........

Posted by: Daniel      Permalink         Source

May 30, 2006, 10:55 PM CT

Making Nerve Fibers Regenerae

Scientists at Children's Hospital Boston have discovered a naturally occurring growth factor that stimulates regeneration of injured nerve fibers (axons) in the central nervous system. Under normal conditions, most axons in the mature central nervous system (which consists of the brain, spinal cord and eye) cannot regrow after injury. The previously unrecognized growth factor, called oncomodulin, is described in the May 14 online edition of Nature Neuroscience.

Neuroresearchers Yuqin Yin, MD, PhD, and Larry Benowitz, PhD, who are also on the faculty of Harvard Medical School, did their studies in the optic nerve, which connects nerve cells in the eye's retina to the brain's visual centers, and is often used as a model in studying axon regeneration.

When oncomodulin was added to retinal nerve cells in a Petri dish, with known growth-promoting factors already present, axon growth nearly doubled. No other growth factor was as potent. In live rats with optic-nerve injury, oncomodulin released from tiny sustained-release capsules increased nerve regeneration 5- to 7-fold when given along with a drug that helps cells respond to oncomodulin. Yin, Benowitz and his colleagues also showed that oncomodulin switches on a variety of genes associated with axon growth.

Benowitz, the study's senior investigator, believes oncomodulin could someday prove useful in reversing optic-nerve damage caused by glaucoma, tumors or traumatic injury. In addition, the lab has shown that oncomodulin works on at least one other type of nerve cell, and now plans to test whether it also works on the types of brain cells that would be relevant to treating conditions like stroke and.........

Posted by: Daniel      Permalink         Source

May 30, 2006, 10:49 PM CT

Breakthrough For Diabetic Neuropathy Treatment

A potentially ground-breaking therapy for nerve damage caused by diabetes has shown promising results in preclinical and early patient trials.

The University of Manchester team has discovered that injection of a novel therapeutic that works by stimulating a person's genes may prevent nerve damage - primarily to the hands and feet - caused by the disease.

The positive preclinical results - published in the journal Diabetes - are further evidence that the research could lead to a new therapy for diabetic nerve damage or 'neuropathy'; initial-stage clinical trials on patients in the United States have also been encouraging.

Lead researcher Professor David Tomlinson says the study has massive potential for managing the condition and preventing thousands of foot amputations each year.

"The vast majority of non-traumatic hand and foot amputations carried out in UK hospitals are caused by diabetes and there are currently no therapys available to prevent or slow the progress of nerve disease in diabetic patients," he said.

"Our tests have shown that a single injection of a DNA-binding protein protected nerve function, stimulated nerve growth and prevented tissue damage that in humans can lead to limb loss."

An estimated 50 per cent of patients with long-term diabetes develop some form of neuropathy that can cause numbness and sometimes pain and weakness in the hands, arms, feet and legs. Progression to amputation is not inevitable, but it is always a threat.........

Posted by: JoAnn      Permalink         Source

May 27, 2006, 7:26 PM CT

Clipping And Coiling Of Aneurysms

A study led by UCSF neurologist S. Claiborne Johnston, MD, has shown that coiling of ruptured brain aneurysms is very effective during long-term follow-up, similar to outcomes with surgical clipping.

Eventhough results of a prior trial suggested that coiling was superior to surgical clipping one year after therapy, a lack of data on long-term outcomes has been a major concern, as per Johnston. The study results are reported in the June 2006 issue of the journal Stroke, a publication of the American Heart Association.

"Aneurysms are very serious. Half of those who suffer a ruptured aneurysm will die from it, and another 30 percent will be permanently disabled," Johnston said. "Aneurysms that rupture once are very likely to bleed again, so therapy is definitely indicated. However, there has been concern that coiling may not work as well to prevent new bleeding, and this has limited its use, especially in the U.S."

There are two main courses of therapy for an aneurysm: clipping the aneurysm, which involves invasive brain surgery, or coiling, which is a procedure in which a small catheter is placed into the groin and threaded up to the brain where a small platinum wire is released into the aneurysm to clot it off from the inside.

"While it is true that some aneurysms can only be treated with clipping and some only with coiling, most patients can be treated with either method," Johnston explained. "This leaves the doctor and the patient in the awkward position to decide which is best. Without good data on long term results, the choice is difficult and may be based on purely anecdotal evidence or the preference of the physician. My hope is that this study will help both patients and physicians make better informed decisions based on that particular patient's situation."........

Posted by: Daniel      Permalink         Source

May 23, 2006, 11:38 PM CT

Lowering Blood Pressure Doesn't Prevent Dementia

Lowering blood pressure does not appear to prevent cognitive or dementia-related disorders, a desired effect in light of the large number of older adults who suffer from both cognitive impairment and hypertension.

Authors of a new systematic review analyzed three studies comprising 12,091 patients with high blood pressure who were treated with either medicine or lifestyle strategies for at least six months while undergoing testing to assess their cognitive function. All were followed for five years.

"There is no convincing evidence that lowering blood pressure prevents the development of dementia or cognitive impairment in hypertensive patients without apparent previous cerebrovascular disease," write co-authors including A. Peter Passmore, M.D., of the department of Public Health Medicine and Primary Care at Queen's University in Belfast, Ireland.

One blood-pressure medication, Nitrendipine, did appear to reduce dementia in one of the studies reviewed, but when combined with all data, this effect was not significant.

The review appears in the current issue of The Cochrane Library, a publication of The Cochrane Collaboration, an international organization that evaluates medical research. Systematic reviews draw evidence-based conclusions about medical practice after considering both the content and quality of existing medical trials on a topic.........

Posted by: Daniel      Permalink         Source

May 23, 2006, 11:27 PM CT

Early Treatment Best For Multiple Sclerosis

An editorial accompanying a published debate on the pros and cons of starting therapy early in the course of multiple sclerosis comes down in favor of early therapy for this potentially devastating disease. This opinion coincides with a consensus paper published by the National MS Society. The recent issue of the Archives of Neurology features both sides of this debate on early therapy for MS.

Background: Currently five therapies are approved by the U.S. Food and Drug Administration for the therapy of multiple sclerosis. These agents can reduce future disease activity for a number of individuals with relapsing forms of MS, including those with secondary progressive disease who continue to have relapses. The National MS Society's Medical Advisory Board recommends that initiating MS treatment with an immunomodulating drug (such as FDA-approved interferons or glatiramer acetate) should be considered as soon as possible following a definite diagnosis of MS with a relapsing course, and for selected patients with a first attack who are at high risk for MS. Some clinicians disagree, however, choosing to defer therapy until the extent of disease activity is more clearly established.

The Debate: E. M. Frohman, MD, PhD (University of Texas Southwestern Medical Center at Dallas) and an international panel of coauthors present the following arguments in favor of early therapy in an article titled, "Most Patients with Multiple Sclerosis or a Clinically Isolated Demyelinating Syndrome Should Be Treated at the Time of Diagnosis" (Archive of Neurology 2006;63:614-619):.........

Posted by: Daniel      Permalink         Source

May 21, 2006, 9:05 AM CT

Surgical Plugs In Ear Bone Helps Dizziness

Rapid, uncontrollable eye movements that swish and thump as the eyes roll and blink. Bones that creak as the body moves. Sudden dizziness, loss of balance. Falling down after a loud noise, such as the sound of your own voice, a cough or even laughter. These are hallmarks of a debilitating and relatively rare syndrome known as superior canal dehiscence that has stumped clinicians for a long time.

Victims lose balance, fall down stairs, are unable to read or sleep due to loud noises inside their head, and some become convinced they are mentally ill, suffering from symptoms that won't yield to conventional therapy. Now, Johns Hopkins surgeons have proven that these symptoms can all be successfully treated by a single operation that plugs up a threadbare layer of bone in the inner ear.

Superior canal dehiscence occurs in roughly equal numbers of men and women and is often not diagnosed until after age 40, when symptoms, such as hearing loss, appear to worsen. However, patients often recall that initial symptoms happened much earlier in their lives.

"The surgical plugging procedure can put a stop to even severe symptoms and can lead to a return to normal daily activities and, in some cases, to a mild-to-moderate improvement in hearing," says Lloyd B. Minor, M.D., the Andelot Professor and director of otolaryngology - head and neck surgery at The Johns Hopkins University School of Medicine. It was Minor who, in 1998, first clinically described superior canal dehiscence and developed the surgical techniques to repair it.........

Posted by: Sue      Permalink         Source

May 18, 2006, 9:40 PM CT

Giving Rest To Restless Legs

Life can be hard. Sometimes you feel sad or distracted or anxious. Or maybe you feel a compelling urge to move your legs. But does that mean you are sick? Does it mean you need medication?

Maybe, maybe not. For some people, symptoms are severe enough to be disabling. But for a number of others with milder problems, these "symptoms" are just the transient experiences of everyday life. Helping sick people get therapy is a good thing. Convincing healthy people that they are sick is not. Sick people stand to benefit from therapy, but healthy people may only get hurt: they get labeled "sick," may become anxious about their condition, and, if they are treated, may experience side effects that overwhelm any potential benefit.

"Disease mongering" is the effort by pharmaceutical companies (or others with similar financial interests) to enlarge the market for a therapy by convincing people that they are sick and need medical intervention [2]. Typically, the disease is vague, with nonspecific symptoms spanning a broad spectrum of severity-from everyday experiences a number of people would not even call "symptoms," to profound suffering. The market for therapy gets enlarged in two ways: by narrowing the definition of health so normal experiences get labeled as pathologic, and by expanding the definition of disease to include earlier, milder, and presymptomatic forms (e.g., regarding a risk factor such as high cholesterol as a disease in itself).........

Posted by: JoAnn      Permalink         Source

May 15, 2006, 11:48 PM CT

New Compound To Block Brain Cancer Growth

By determining how a class of compounds blocks signaling in cells, UCSF researchers have identified what is perhaps the most potent drug candidate yet against a highly lethal kind of brain tumor.

The compound, known as PI-103, shows unique potency against cancer cell proliferation in studies of mice with grafts of human glioma cells. Gliomas are the most common form of brain cancer, and have proven very difficult to treat.

The unique effectiveness of PI-103 stems from its ability to attack two separate steps in the series of signals that trigger the spread of cancer. The dual blockade proved to be a safe and effective inhibitor of cancer cell proliferation in mice with the human tumors, the researchers found.

The glioma research is being published online May 15 by the journal Cancer Cell. A description of the strategy used to identify the molecular level action of the inhibitors was published online by the journal Cell on April 27.

Food and Drug Administration approval five years ago of the cancer drug Gleevec marked a promising new strategy against cancer. Gleevec was the first drug on the market designed to block ubiquitous signaling molecules called protein kinases - enzymes known to trigger normal cell proliferation, and in the case of cancer, the growth of tumors. Another group of kinases, called lipid kinases are now emerging as important new targets, particularly PI3 alpha kinase, an enzyme often found to be overactive in brain, breast, colon and stomach cancers.........

Posted by: Janet      Permalink         Source

May 15, 2006, 11:43 PM CT

New Compound Reduces Stroke Damage

A group of German researchers has synthesized a new compound that dramatically decreases the damage to neurons in rats demonstrating stroke symptoms. The research appears as the "Paper of the Week" in the May 26 issue of the Journal of Biological Chemistry, an American Society for Biochemistry and Molecular Biology journal.

Stroke is the third leading cause of death in the United States and the most common cause of adult disability. An ischemic stroke occurs when a cerebral vessel occludes, obstructing blood flow to a portion of the brain. Currently, there is only one approved stroke treatment, tissue plasminogen activator, which targets the thrombus within the blood vessel. Because of the lack of available stroke therapys, neuroprotective agents have also generated as much interest as thrombolytic therapies.

The immunosuppressive drug FK506 (also known as Tacrolimus or Prograf®) is often administered to patients receiving transplants to prevent organ rejection. Dervatives of the drug are also usually used in the therapy of autoimmune diseases. FK506 inhibits T-cell activation by binding to members of the FK506-binding protein (FKBP) family. Interestingly, FK506, and several molecules with similar structures, also demonstrate neuroprotective and neuroregenerative effects in a wide range of animal models mimicking Parkinson's disease, dementia, stroke, and nerve damage.........

Posted by: Daniel      Permalink         Source