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October 9, 2009, 7:17 AM CT

Amyotrophic lateral sclerosis

Amyotrophic lateral sclerosis
Premature aging of the immune system appears to play a role in the development of amyotrophic lateral sclerosis (ALS), or Lou Gehrig's disease, as per research researchers from the Maxine Dunitz Neurosurgical Institute at Cedars-Sinai Medical Center, the Weizmann Institute of Science in Israel, and Sheba Medical Center in Israel.

A study reported in the Journal of Cellular and Molecular Medicine shows that CD4+ T cells, which grow and mature in the thymus before entering the bloodstream, are reduced in number in patients who have ALS as the thymus shrinks and malfunctions. Theoretically, devising therapies to support or replace these cells could be a strategy in treating the disease.

The research was led by Michal Schwartz, Ph.D., a visiting professor at the Center of Neuroimmunology and Neurogenesis in the Department of Neurosurgery at Cedars-Sinai and professor of neuroimmunology at the Weizmann Institute in Rehovot, Israel.

The findings are consistent with evidence collected over a decade by Schwartz's group suggesting that a well-functioning immune system plays a pivotal role in maintaining, protecting and repairing cells of the central nervous system. Studies conducted in animals have shown that boosting immune T-cell levels may reduce symptoms and slow progression of certain neurodegenerative diseases.........

Posted by: Daniel      Read more         Source


September 29, 2009, 10:20 PM CT

A step forward: Brain implants using polymer nanotubes

A step forward: Brain implants using polymer nanotubes
This illustration depicts neurons firing (green structures in the foreground) and communicating with nanotubes in the background. Illustration courtesy of Mohammad Reza Abidian
Brain implants that can more clearly record signals from surrounding neurons in rats have been created at the University of Michigan. The findings could eventually lead to more effective therapy of neurological disorders such as Parkinson's disease and paralysis.

Neural electrodes must work for time periods ranging from hours to years. When the electrodes are implanted, the brain first reacts to the acute injury with an inflammatory response. Then the brain settles into a wound-healing, or chronic, response.

It's during this secondary response that brain tissue starts to encapsulate the electrode, cutting it off from communication with surrounding neurons.

The new brain implants developed at U-M are coated with nanotubes made of poly(3,4-ethylenedioxythiophene) (PEDOT), a biocompatible and electrically conductive polymer that has been shown to record neural signals better than conventional metal electrodes.

U-M scientists observed that PEDOT nanotubes enhanced high-quality unit activity (signal-to-noise ratio >4) about 30 percent more than the uncoated sites. They also observed that based on in vivo impedance data, PEDOT nanotubes might be used as a novel method for biosensing to indicate the transition between acute and chronic responses in brain tissue.........

Posted by: Daniel      Read more         Source


September 23, 2009, 7:18 AM CT

Rethinking Alzheimer's disease and its treatment targets

Rethinking Alzheimer's disease and its treatment targets
The standard explanation for what causes Alzheimer's is known as the amyloid hypothesis, which posits that the disease results from of an accumulation of the peptide amyloid beta, the toxic protein fragments that deposit in the brain and become the sticky plaques that have defined Alzheimer's for more than 100 years.

Billions of dollars are spent yearly targeting this toxic peptide but what if this is the wrong target? What if the disease begins much earlier, fueled by a natural process? Reporting in the current edition of the journal Neurobiology of Aging, UCLA professor of psychiatry George Bartzokis argues just that and says that a better working hypothesis is the "myelin model." .

"The greatest promise of the myelin model of the human brain is its application to the development of new therapeutic approaches," Bartzokis said.

Like insulation around wires, myelin is a fatty sheath that coats our nerve axons, allowing for efficient conduction of nerve impulses. It is key to the fast processing speeds that underlie our higher cognitive functions and encoding of memories.

But the lifelong, extensive myelination of the human brain also makes it uniquely vulnerable to damage. The myelin model's central premise is that it is the normal, routine maintenance and repair of myelin throughout life that ultimately initiates the mechanisms that produce degenerative diseases like Alzheimer's. That is, the amyloid-beta peptide and the tau peptide, which is also implicated in Alzheimer's, as well as the signature clinical signs of the disease, such as memory loss and, ultimately, dementia, are all byproducts of the myelin breakdown and repair processes.........

Posted by: Daniel      Read more         Source


September 15, 2009, 9:25 PM CT

Role of Sleep in Memory Formation

Role of Sleep in Memory Formation
A Rutgers University, Newark and College de France, Paris research team has pinpointed for the first time the mechanism that takes place during sleep that causes learning and memory formation to occur.

It's been known for more than a century that sleep somehow is important for learning and memory. Sigmund Freud further suspected that what we learned during the day was "rehearsed" by the brain during dreaming, allowing memories to form. And while much recent research has focused on the correlative links between the hippocampus and memory consolidation, what had not been identified was the specific processes that cause long-term memories to form.

As posted online September 11, 2009 by Nature Neuroscience, Gyorgy Buzsaki, professor at the Center for Molecular and Behavioral Neuroscience at Rutgers University, Newark, and his co-researchers, Gabrielle Girardeau, Karim Benchenane, Sidney I. Wiener and Michaƫl B. Zugaro of the College de France, have determined that short transient brain events, called "sharp wave ripples," are responsible for consolidating memory and transferring the learned information from the hippocampus to the neocortex, where long-term memories are stored. www.nature.com/neuro/journal/vaop/ncurrent/abs/nn.2384.html.

Sharp wave ripples are intense, compressed oscillations that occur in the hippocampus when the hippocampus is working "off-line," most often during stage four sleep, which, along with stage three, is the deepest level of sleep.........

Posted by: Daniel      Read more         Source


September 15, 2009, 7:26 PM CT

Brain's response to seeing food and weight loss maintenance

Brain's response to seeing food and weight loss maintenance
A difference in brain activity patterns may explain why some people are able to maintain a significant weight loss while others regain the weight, as per a newly released study by scientists with The Miriam Hospital.

The researchers report that when individuals who have kept the weight off for several years were shown pictures of food, they were more likely to engage the areas of the brain linked to behavioral control and visual attention, in comparison to obese and normal weight participants.

Findings from this brain imaging study, published by the American Journal of Clinical Nutrition, suggest that successful weight loss maintainers may learn to respond differently to food cues.

"Our findings shed some light on the biological factors that may contribute to weight loss maintenance. They also provide an intriguing complement to prior behavioral studies that suggest people who have maintained a long-term weight loss monitor their food intake closely and exhibit restraint in their food choices," said main author Jeanne McCaffery, PhD, of The Miriam Hospital's Weight Control and Diabetes Research Center.

Long-term weight loss maintenance continues to be a major problem in obesity therapy. Participants in behavioral weight loss programs lose an average of 8 to 10 percent of their weight during the first six months of therapy and will maintain approximately two-thirds of their weight loss after one year. However, despite intensive efforts, weight regain appears to continue for the next several years, with most patients returning to their baseline weight after five years.........

Posted by: Daniel      Read more         Source


September 15, 2009, 7:52 AM CT

New marker for Alzheimer's

New marker for Alzheimer's
This is Erik Portelius, a biochemist at University of Gothenburg.

Gothenburg scientists have discovered a previously unknown substance in spinal fluid that can be used to diagnose Alzheimer's disease. The findings, described in a thesis from the Sahlgrenska Academy at the University of Gothenburg, Sweden, will also be useful in research on new medications.

The substance is a beta-amyloid protein called Abeta16. The thesis shows in two independent studies that Alzheimer's patients have higher levels of the protein in their spinal fluid than do healthy individuals.

'The discovery of the new protein could be used to diagnose patients with Alzheimer's and also help determine which medications are most effective for the disease', says biochemist Erik Portelius, the author of the thesis.

Alzheimer's disease includes the formation of plaque on the brain. Neurons and other cell types form around 20 different beta-amyloid proteins, and these are excreted into the spinal fluid around the brain.

'These types of beta-amyloid proteins can be analysed with great precision, and our research team has also shown that the analyses can be used to distinguish between Alzheimer's patients and healthy individuals with a high degree of accuracy', says Portelius.

The beta-amyloid protein Abeta42 is especially prevalent in the plaque. Abeta42 is created when a larger protein is cut into pieces by certain enzymes. The new Alzheimer's drugs that are currently being tested aim to reduce the production of Abeta42 by blocking these enzymes. Portelius observed that these drugs increase the level of the newly discovered Abeta16.........

Posted by: Daniel      Read more         Source


September 15, 2009, 7:38 AM CT

Neurons found to be similar to Electoral College

Neurons found to be similar to Electoral College
A tiny neuron is a very complicated structure. Its complex network of dendrites, axons and synapses is constantly dealing with information, deciding whether or not to send a nerve impulse, to drive a certain action.

It turns out that neurons, at one level, operate like another complicated structure -- the United States, especially its system of electing a president, through the Electoral College.

A new Northwestern University study provides evidence that supports the "two-layer integration model," one of several competing models attempting to explain how neurons integrate synaptic inputs. The findings appear in the journal Neuron

In this model, each dendritic branch of a neuron receives and integrates thousands of electrical inputs, deciding on just one signal to send to the axon. The axon then receives signals from all the dendrites, much like electoral votes coming in from state elections, and a final decision is made. The result could be an output in the form of an impulse, or action potential, or no action at all.

"There are more than 100 billion neurons in the human brain, so detailed knowledge of individual neurons will lead to a better understanding of how the brain works, including the processes of learning and memory," said Nelson Spruston, who led the research team. He is professor of neurobiology and physiology in the Weinberg College of Arts and Sciences at Northwestern.........

Posted by: Daniel      Read more         Source


September 10, 2009, 7:04 AM CT

Toward a nanomedicine for brain cancer

Toward a nanomedicine for brain cancer
Brain cancer cells like those in this tumor could someday become the target of nanoparticles that in lab experiments seek out and destroy brain cancer cells without harming healthy cells.
In an advance toward better therapys for the most serious form of brain cancer, researchers in Illinois are reporting development of the first nanoparticles that seek out and destroy brain cancer cells without damaging nearby healthy cells. The study is scheduled for the Sept. 9 issue of ACS' Nano Letters, a monthly journal.

Elena Rozhkova and his colleagues note the pressing need for new ways to treat the disease, glioblastoma multiforme (GBM), which often causes death within months of diagnosis. Recent studies show that titanium dioxide nanoparticles, a type of light-sensitive material widely used in sunscreens, cosmetics, and even wastewater therapy, can destroy some cancer cells when the chemical is exposed to ultraviolet light. However, researchers have had difficulty getting nanoparticles, each about 1/50,000th the width of a human hair, to target and enter cancer cells while avoiding healthy cells.

The scientists' solution involves chemically linked titanium dioxide nanoparticles to an antibody that recognizes and attaches to GMB cells. When they exposed cultured human GMB cells to these so-called "nanobio hybrids," the nanoparticles killed up to 80 percent of the brain cancer cells after 5 minutes of exposure to focused white light. The results suggest that these nanoparticles could become a promising part of brain cancer treatment, when used during surgery, the scientists say.........

Posted by: Janet      Read more         Source


September 9, 2009, 7:38 AM CT

Healthy older brains not significantly smaller

Healthy older brains not significantly smaller
WASHINGTON -- The belief that healthy older brains are substantially smaller than younger brains may stem from studies that did not screen out people whose undetected, slowly developing brain disease was killing off cells in key areas, as per new research. As a result, prior findings may have overestimated atrophy and underestimated normal size for the older brain.

The newly released study tested participants in Holland's long-term Maastricht Aging Study who were free of neurological problems such as dementia, Parkinson's disease or stroke. Once participants were deemed otherwise healthy, they took neuropsychological tests, including a screening test for dementia, at baseline and every three years afterward for nine years.

As per the report in the September Neuropsychology, published by the American Psychological Association, participants were also given MRI scans at Year 3 to measure seven different parts of the brain, including the memory-laden hippocampus, the areas around it, and the frontal and cingulate areas of the cognitively critical cortex.

After examining behavioral data collected from 1994 to 2005 (with scans taken between 1997 and 1999 depending on when people entered the study), the scientists divided participants into two groups: one group with 35 cognitively healthy people who stayed free of dementia (average starting age 69.1 years), and the other group with 30 people who showed substantial cognitive decline but were still dementia-free (average starting age 69.2 years).........

Posted by: Daniel      Read more         Source


September 9, 2009, 7:33 AM CT

Face processing slows with age

Face processing slows with age
Identifying a face can be difficult when that face is shown for only a fraction of a second. However, young adults have a marked advantage over elderly people in these conditions. Scientists writing in the open access journal BMC Neuroscience found indications that elderly people have reduced perception speed.

Guillaume Rousselet, from the University of Glasgow, UK, worked with a team of scientists to study electric activity from the brains of young and old people as they watched pictures of faces with cloud-like noise. He said, "Very few studies have attempted to measure the effect of ageing on the time-course of visual processing in response to complex stimuli like faces. We observed that, as well as a general reduction in speed in the elderly, one particular component of the response to a face, the N170, is less sensitive to faces in the elderly".

The N170 occurs 170 milliseconds after a stimulus is presented. In the young, it was more closely linked to the appearance of a face, while in older subjects it occurred also in response to noise, perhaps implying reduced ability to differentiate faces from noise. Speaking about the results, Rousselet said, "Our data support the common belief that as we get older we get slower. Beyond this general conclusion, our research provides new tools to quantify by how much the brain slows down in the particular context of face perception. Now, we need to identify the reasons for the speed reduction and for the heterogeneity of the effects indeed, why the brains of some older subjects seem to tick as fast as the brains of some young subjects is, at this point, a complete mystery".........

Posted by: Daniel      Read more         Source



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Did you know?
The drug Ativan is better than Valium or Dilantin for controlling severe epileptic seizures, according to a new review of studies.Ativan, or lorazepam, and Valium, or diazepam, are both benzodiazepines, the currently preferred class of drugs for treating severe epileptic seizures. Dilantin, or phenytoin, is an anticonvulsant long used for the treatment of epileptic seizures.

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