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January 15, 2007, 5:07 AM CT

New Genetic Clue To Cause Of Alzheimer's Disease

New Genetic Clue To Cause Of Alzheimer's Disease Tangles Alzheimer's
Variations in a gene known as SORL1 may be a factor in the development of late onset Alzheimer's disease, an international team of scientists has discovered. The genetic clue, which could lead to a better understanding of one cause of Alzheimer's, is reported in Nature Genetics online, Jan. 14, 2007, and was supported in part by the National Institutes of Health (NIH).

The scientists suggest that faulty versions of the SORL1 gene contribute to formation of amyloid plaques, a hallmark sign of Alzheimer's in the brains of people with the disease. They identified 29 variants that mark relatively short segments of DNA where disease-causing changes could lie. The study did not, however, identify specific genetic changes that result in Alzheimer's.

Richard Mayeux, M.D., of Columbia University, Lindsay Farrer, Ph.D., of Boston University, and Peter St. George-Hyslop, M.D., of the University of Toronto, led the study, which involved 14 collaborating institutions in North America, Europe and Asia, and 6,000 individuals who donated blood for genetic typing. The work was funded by NIH's National Institute on Aging (NIA) and National Human Genome Research Institute (NHGRI), as well as by 18 other international public and private organizations.

"We do not fully understand what causes Alzheimer's disease, but we know that genetic factors can play a role," says NIA director Richard J. Hodes, M.D. "Researchers have previously identified three genes, variants of which can cause early onset Alzheimer's, and one that increases risk for the late onset form. This discovery provides a completely new genetic clue about the late onset forms of this very complex disease. We are eager to investigate the role of this gene further".........

Posted by: Daniel      Read more         Source


January 12, 2007, 4:57 AM CT

Bilingualism Has Protective Effect On Dementia

Bilingualism Has Protective Effect On Dementia
Canadian researchers have found astonishing evidence that the lifelong use of two languages can help delay the onset of dementia symptoms by four years in comparison to people who are monolingual.

There has been much interest and growing scientific literature examining how lifestyle factors such as physical activity, education and social engagement may help build "cognitive reserve" in later years of life. Cognitive reserve refers to enhanced neural plasticity, compensatory use of alternative brain regions, and enriched brain vasculature, all of which are thought to provide a general protective function against the onset of dementia symptoms.

Now researchers with the Rotman Research Institute at the Baycrest Research Centre for Aging and the Brain have found the first evidence that another lifestyle factor, bilingualism, may help delay dementia symptoms. The study is reported in the February 2007 issue of Neuropsychologia (Vol.45, No.2).

"We are pretty dazzled by the results," says principal investigator Ellen Bialystok, Ph.D., whose research team at Baycrest included psychology expert Dr. Fergus Craik, a world authority on age-related changes in memory processes, and neurologist Dr. Morris Freedman, an eminent authority on understanding the mechanisms underlying cognitive impairment due to diseases such as Alzheimer's.........

Posted by: Daniel      Read more         Source


January 7, 2007, 9:32 PM CT

The Molecular Basis Of Memory

The Molecular Basis Of Memory
Phone numbers, the way to work, granny's birthday -- our brain with its finite number of nerve cells can store incredible amounts of information. At the bottom of memory lies a complex network of molecules. To understand how this network brings about one of the most remarkable capacities of our brain we need to identify its components and their interactions. Scientists from the European Molecular Biology Laboratory's (EMBL) Mouse Biology Unit in Monterotondo, Italy, and the Universidad Pablo de Olavide in Sevilla, Spain, now for the first time investigate the molecular basis of memory in living mice. The study, which appears in the current issue of Learning and Memory, identified a molecule that is crucially involved in learning and singled out the signaling pathway through which it affects memory.

Our sense organs inform our brain about what happens around us and brain cells communicate this information between each other using electrical signals. These signals become stronger the more often a cell experiences the same stimulus allowing it to distinguish familiar information from news. In other words a cell remembers an event as an uncommonly strong and long-lasting signal. This phenomenon called long-term potentiation (LTP) is thought to underpin learning and memory and its molecular basis is being investigated intensively.........

Posted by: Daniel      Read more         Source


December 28, 2006, 8:53 PM CT

Insights Into Learning

Insights Into Learning Leonid Moroz
Credit: Sarah Kiewel/UF HSC News
Researchers analyzing the genomics of a marine snail have gotten an unprecedented look at brain mechanisms, discovering that the neural processes in even a simple sea creature are far from sluggish.

At any given time within just a single brain cell of sea slug known as Aplysia, more than 10,000 genes are active, as per researchers writing in Friday's (Dec. 29, 2006) edition of the journal Cell. The findings suggest that acts of learning or the progression of brain disorders do not take place in isolation - large clusters of genes within an untold amount of cells contribute to major neural events.

"For the first time we provide a genomic dissection of the memory-forming network," said Leonid Moroz, a professor of neuroscience and zoology at the University of Florida Whitney Laboratory for Marine Bioscience. "We took advantage of this powerful model of neurobiology and identified thousands of genes operating within a single neuron. Just during any simple event correlation to memory formation, we expect differences in gene expression for at least 200 to 400 genes".

Scientists studied gene expression in association with specific networks controlling feeding or defensive reflexes in the sea slug. To their surprise, they identified more than 100 genes similar to those linked to all major human neurological diseases and more than 600 genes controlling development, confirming that molecular and genomic events underlying key neuronal functions were developed in early animal ancestors and remained practically unchanged for more than 530 million years of independent evolution in the lineages leading to men or sea slugs.........

Posted by: Daniel      Read more         Source


December 26, 2006, 7:54 PM CT

Incidence Of Stroke Decreasing

Incidence Of Stroke Decreasing
The occurence rate of stroke in the U.S. over the past 50 years has declined, eventhough the severity of stroke has not, as per a research studyin the December 27 issue of JAMA.

Stroke continues to be a major public health concern, with more than 750,000 new strokes occurring each year in the United States. It is the third leading cause of death behind heart disease and cancer and the leading neurologic cause of long-term disability, as per background information in the article. Previous estimates of long-term trends in the incidence and severity of stroke have varied. Determining trends could help guide health programs, public policy, and the allocation of research funding.

Raphael Carandang, M.D., of Boston University, and his colleagues examined data from the Framingham Study (health study, with participants initially recruited in 1948) to determine long-term trends in the incidence, lifetime risk, severity, and 30-day risk of death from clinical stroke. This study included 9,152 Framingham Study original participants and offspring undergoing follow-up for up to 50 years over three consecutive time-periods (1950-1977, 1978-1989, and 1990-2004), with ascertainment of stroke risk factor data every 2 years and active surveillance for occurrence of stroke or death.........

Posted by: Daniel      Read more         Source


December 20, 2006, 7:22 PM CT

Botox Can Ease Writer's Cramp

Botox Can Ease Writer's Cramp
"Botox"' the popular anti- wrinkle therapy, can also ease writer's cramp, suggests a small study published ahead of print in the Journal of Neurology Neurosurgery and Psychiatry.

Writer's cramp describes the painful involuntary, spasmodic muscle contractions of the fingers, hand, or arm during writing. But it can also occur during other manual tasks.

Some people learn to write with their other hand, but in one in four cases, the condition affects both hands, and the condition is difficult to treat. It affects around three to seven in every 100,000 people.

Relaxation techniques, hypnosis, biofeedback, acupuncture, and 'writing re-education exercises' have all been used, but none of these brings sustained relief. And there is as yet no effective drug therapy.

Forty people with writer's cramp were randomly assigned to a course of injections containing either botulinum toxin (botox) or a dummy substitute in two doses, commonly into two muscles, over a period of 12 weeks.

Of the 20 people given botox therapy, 14 (70%) said that their condition had significantly improved, and that they wished to continue therapy. Their improvement was confirmed using validated disability and pain scales.

Only six of the 19 people in the dummy group felt that their condition had improved. One person dropped out of the trial.........

Posted by: Daniel      Permalink         Source


December 20, 2006, 5:05 AM CT

Androgen Therapy To Slow Progress Of Alzheimer's Disease

Androgen Therapy To Slow Progress Of Alzheimer's Disease
Experiments on mouse models of Alzheimer's disease (AD) suggest that therapy with male sex hormones might slow its progression. The findings, reported in the December 20 issue of The Journal of Neuroscience, provide new insight into the relationship between testosterone loss and AD, which affects 4.5 million Americans.

Senior author Christian Pike, PhD, of the University of Southern California (USC), with colleagues at USC and the University of California, Irvine, sought to better understand the role hormones play in aging and disease. Recent studies had already established a link between testosterone loss in men and AD due to natural aging.

The research team established a connection between low testosterone and elevated beta-amyloid (A), a protein that accumulates abnormally in AD patients. This finding, they say, suggests that testosterone depletion in aging men may be a risk factor for AD by promoting accumulation of A in the brain. Testosterone, the primary male sex hormone, is one in a group of related steroid hormones referred to as androgens. Recent studies suggest that androgens may lower A levels.

"This study raises the possibility that androgen replacement treatment might lower the risk for Alzheimer's, but this is far from proven," says Sam Gandy, MD, PhD, chair of the Alzheimer's Association's Medical and Scientific Advisory Council and director of the Farber Institute for Neurosciences at Thomas Jefferson University. "Because testosterone is rapidly converted to estrogen after entry into neurons, the new data are logical, and they dovetail well with historical data".........

Posted by: Daniel      Permalink         Source


December 20, 2006, 4:41 AM CT

Impulsiveness Linked To Brain's Reward Center

Impulsiveness Linked To Brain's Reward Center
If you are acting lately very impulsively now you can blame on your brain. A new imaging study shows that our brains react with varying sensitivity to reward and suggests that people most susceptible to impulse&mdashthose who need to buy it, eat it, or have it, nowshow the greatest activity in a reward center of the brain. The study appears in the December 20 issue of The Journal of Neuroscience

In their study of 45 subjects, Ahmad Hariri, PhD, and his colleagues at the University of Pittsburgh and collaborators at Mount Sinai School of Medicine and the University of Chicago showed that activity in the ventral striatum, a core component of the brain's reward circuitry, correlated with individuals' impulsiveness.

"These data are exciting because they begin to unravel individual differences in brain organization underlying differences in complex psychological constructs, such as 'impulsivity,' which may contribute to the propensity to addiction," says Terry E. Robinson, PhD, of the University of Michigan biopsychology program.

The Hariri team tested the subjects on two computer-based tasks. First, participants indicated their preferences in a series of immediate-versus-delayed, hypothetical monetary rewards. They chose between receiving an amount from 10 cents to $105 that day and receiving $100 at one of seven points up to five years in the future. "Switch points"the value at which they were equally likely to choose getting money today as getting $100 at a future point in timewere calculated for each person.........

Posted by: JoAnn      Permalink         Source


December 20, 2006, 4:15 AM CT

Language Used By Nerve Cells

Language Used By Nerve Cells Image showing junction (green) between nerve (red) and muscle cells (blue)
Credit: Laura N. Borodinsky, UCSD
UC San Diego biologists have shown that the chemical language with which neurons communicate depends on the pattern of electrical activity in the developing nervous system. The findings suggest that modification of nerve activity could have potential as a therapy for a wide range of brain disorders.

In the study, published this week in the early on-line edition of the journal Proceedings of the National Academy of Sciences, the biologists showed that, contrary to the prevailing viewpoint, neurotransmitters-the chemical language of nerve cells-and receptors-the proteins that receive and respond to neurotransmitters-are not specified by a rigid genetic program. Altering nerve activity during development determines the "mother tongue" nerve cells use to communicate. The study will appear in the print edition of PNAS on January 2.

"Most cognitive disorders, such as depression, schizophrenia and Parkinson's disease, involve problems with neurotransmitters or neurotransmitter receptors," said Nicholas Spitzer, a professor of biology and the senior author of the study. "If modifying electrical activity in the adult brain can alter neurotransmitters and receptors similarly to the way we have discovered in the developing frog nervous system, it could provide a promising approach to treating these disorders".........

Posted by: Daniel      Permalink         Source


December 15, 2006, 5:13 AM CT

Learning During Sleep?

Learning During Sleep? Image of a hippocampal interneuron with associated electrical readings
The question of how the brain stores or discards memories still remains largely unexplained. A number of brain scientists regard the consolidation theory as the best approach so far. This states that fresh impressions are first stored as short-term memories in the hippocampus. They are then said to move within hours or a few days - commonly during deep sleep - into the cerebral cortex where they enter long-term memory. Investigations by Thomas Hahn, Mayank Mehta and the Nobel Prize winner Bert Sakmann from the Max Planck Institute for Medical Research in Heidelberg have now shed new light on the mechanisms that create memory. As per their findings, the areas of the brain work together, but possibly in a different way from that previously assumed. "This is a technically sophisticated study which could have considerable influence on our understanding of how nerve cells interact during sleep consolidation," confirmed Edvard Moser, Director of the Centre for the Biology of Memory in Trondheim, Norway.

It has been difficult up to now to use experiments to examine the brain processes that create memory. The researchers in Heidelberg developed an innovative experimental approach particularly for this purpose. They succeeded in measuring the membrane potential of individual interneurones (neurones that suppress the activity of the hippocampus) in anaethetised mice. At the same time, they recorded the field potential of thousands of nerve cells in the cerebral cortex. This allowed them to link the behaviour of the individual nerve cells with that of the cerebral cortex. The scientists discovered that the interneurones they examined are active at almost the same time as the field potential of the cerebral cortex. There was just a slight delay, like an echo.........

Posted by: Daniel      Permalink         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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