Links for Keyword: Huntingtons
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By John McCarthy Maybe this discovery is interesting because it sheds therapeutic light on the dreaded neurodegenerative diseases that killed Woody Guthrie and Lou Gehrig. Or maybe it’s fascination with healthy cells, and yet another unsuspected complexity in how they work. What’s discovered: a previously unknown energy source in nerve cells. It propels the molecular “motors” that drag neurotransmitters from the nucleus where they’re made. The “motors” are assemblies of molecules. They walk like clumsy robots, with a staggering gait, dragging a capsule of neurotransmitter “bullets” along microtubule “highways” between nucleus and synapses. They move by flinging their boot-like feet (lavender blobs, in the image) forward, a billionth of a meter at each step. (A superb animation of “motors” in action is XVIVO’s “Life of a Cell” (at ~1:15 of playing time)). When the cargo finally arrives at the synapses, neurotransmitters are loaded into compartments at the synapse’s interior face, like bullets into a magazine. They are ready to be “fired” across a synapse to signal an adjoining neuron. It’s this transport of neurotransmitter “bullets” that failed in Guthrie’s and Gehrig’s nerve cells. Their synapses had nothing to fire. What powers the flinging that moves those boots? Previously, the answer has been specialized molecules (acronym: ATP) spewed into the cell’s fluid interior by mitochondria. The boots, it was thought, powered each step by grabbing a floating ATP and blowing it up like a firecracker. © 2013 Scientific American
Related chapters from BP6e: Chapter 11: Motor Control and Plasticity; Chapter 2: Functional Neuroanatomy: The Nervous System and Behavior
Related chapters from MM:Chapter 5: The Sensorimotor System; Chapter 2: Cells and Structures: The Anatomy of the Nervous System
Link ID: 17978 - Posted: 04.02.2013
By Gary Stix 14 inSharHuntington’ disease, which killed folk singer Woody Guthrie, seems to put into overdrive the main chemical that turns on brain cells, ultimately leading to their death. The normal function of the neurotransmitter glutamate, the chemical overproduced in Huntington’s, is also intimately involved with learning. Researchers from Ruhr University and the University of Dortmund in Germany have been intrigued by the question of whether the neurodegeneration initiated by glutamate in this genetic disorder is all bad. Is it simply burning out brain circuits? Or might an excess of the chemical also help presymptomatic carriers of the Huntington’s gene or even patients with the disease itself, learn some things faster or better? “Neurotransmission causes cell death but we know from the vast amount of literature that learning processes very much depend on glutamate neurotransmission; so there may be two effects of one and the same process,” says Christian Beste of Ruhr University. “On the one hand this process may lead to neurodegeneration. But on the other hand, it may augment a cognitive process that depends on glutamate transmission.” Beste is the lead author on a paper published this month in Current Biology that found that those who have the genetic mutation for Huntington’s but who have yet to develop inevitable symptoms of the disease perform better on a learning task than a control group that lacks the mutation. The 29 Huntington’s gene carriers learned to detect twice as fast as the 45 controls a change in brightness of a small bar as its orientation on a computer screen altered. In fact, the Huntington’s carriers with the most pronounced mutations—the number of repetitions of a short DNA segment determines how early disease onset occurs—logged the best performance. © 2012 Scientific American,
By Kathleen Raven A compound already sitting on the shelves of biomedical laboratories and emergency room supply closets seems to interrupt the formation of neurodegenerative protein clumps found in Huntington’s disease, according to a preliminary animal study published August 7 in the Journal of Neuroscience. This versatile agent, called methylene blue, gets a mention in medical literature as early as 1897 and was used to treat, at one time or another, ailments ranging from malaria to cyanide poisoning. The U.S. Food and Drug Administration has never formally approved it as a therapy for any illnesses. But that fact hasn’t stopped biomedical researchers from tinkering with the agent’s apparent ability to improve cognitive function. And although the new paper out today relies on a Huntington’s disease model in flies and mice, scientists are hopeful. "Because of existing knowledge of methylene blue and the fact that it’s not harmful to humans, I would hope that progress toward clinical trials could go relatively quickly," says Leslie Thompson, a neurobiologist at University of California–Irvine and lead author on the new study. Huntington’s disease occurs when the C-A-G sequence of DNA base pairs repeat too often on the HTT gene, resulting in an abnormally long version of the huntingtin protein, that therefore folds incorrectly and forms clumps in the brain. The illness usually begins to affect people in their 30s and 40s, causing movement problems and early death. No drug is currently available to stop the disease from progressing. © 2012 Scientific American
By James Gallagher Health and science reporter, BBC News People with Huntington's disease, a debilitating brain condition, appear have a "protection" from cancer, according to a study in Sweden. Nearly 40 years of medical records showed patients with Huntington's had half the normal expected risk of developing tumours. Researchers, writing in The Lancet Oncology, said the reason was unclear. Cancer Research UK said the findings presented another avenue to explore in tackling cancer. Academics at Lund University analysed Swedish hospital data from 1969 to 2008. They found 1,510 patients with Huntington's disease. During the study period, 91 of those patients subsequently developed cancer. The authors said that was 53% lower than the levels expected for the general population. Huntington's is one of a group of illnesses called "polyglutamine diseases". Data from other polyglutamine diseases also showed lower levels of cancer. The authors said: "We found that the incidence of cancer was significantly lower among patients with polyglutamine diseases than in the general population. "The mechanisms behind the protective effects against cancer are unclear and further research is warranted." BBC © 2012
By msnbc.com staff and news services A 9-year-old Detroit-area girl whose battle with Huntington's disease drew attention after she was taunted online in 2010 by her grandmother's former neighbor has died. Michigan Memorial Funeral Home in Flat Rock, which is handling arrangements, says Kathleen Edward died Wednesday. One Facebook posting was of her doctored photo placed above a set of crossbones and another included a photo of her mother in the arms of the grim reaper. The conflict with the neighbor reportedly stemmed from a misunderstanding with the girl's family. After the Facebook taunts appeared, people worldwide voiced their support of the young girl on Facebook and raised money to send her on a shopping spree in 2010, according to the Detroit Free Press. Huntington's disease is a genetic, incurable brain disorder which, in children, can cause tremors, slow, rigid movements and seizures. Kathleen's mother also died from the degenerative disease in 2009, the newspaper reported. If one parent has Huntington's disease, a child has a 50 percent chance of getting it. Most people with Huntington's disease develop symptoms in their 40s or later, but when younger people get it, the disease tends to progress more quickly, according to the Mayo Clinic. "She suffered with this disease for a while, and she never complained," her grandmother, Rebecca Rose, told the Detroit Free Press. "She was always happy, always smiling." © 2012 msnbc.com
By Nick Bascom Scientists on the trail of treatments for Huntington’s disease may have found a way to track their success. A new study reports that patients with Huntington’s disease have higher levels of expression of a gene called H2AFY in their blood compared with healthy people. What’s more, patients treated with a drug that slows the effects of the disease had reduced levels of H2AFY activity compared with people given a placebo. The results suggest that H2AFY could serve as a tool for monitoring the progression of the disease and an indicator of whether prospective treatments are working, researchers report online October 3 in the Proceedings of the National Academy of Sciences. “Biomarker identification for Huntington’s disease is critically important for clinical trials,” says Leslie Thompson, director of the Interdepartmental Neuroscience Program at the University of California, Irvine, who was not involved in the study. Huntington’s disease is a hereditary movement disorder marked by involuntary bodily twitches and jerks. The damage the disorder does to nerve cells also causes severe depression and impairs a patient’s ability to reason clearly. “It’s a devastating disease,” and one for which there is no cure, says neurologist Clemens Scherzer of Brigham and Women’s Hospital in Boston, who led the new study. © Society for Science & the Public 2000 - 2011
By Tina Hesman Saey There’s a little Hannibal Lecter in all of us. But while the famous cannibal dined on chunks of his enemies and friends, most people stick to gnawing on themselves at a microscopic level. In fact, the cells of organisms from yeast to humans regularly engage in self-cannibalism. Cells chew on bits of their cytoplasm — the jellylike substance that fills their bellies — and dine on their own internal organs, although usually without the fava beans and Chianti. It may sound macabre, but gorging on one’s own innards, a process called autophagy, is a means of self-preservation, cleansing and stress management. “It has become evident that it is really an essential or vital function,” says Fulvio Reggiori, a cell biologist at the University Medical Center Utrecht in the Netherlands. A munch here gets rid of garbage that might otherwise clog the system. A nibble there rids cells of malfunctioning parts. One chomp disposes of invading microbes. In lean times, all that stands between a cell and starvation may be the ability to bite off and recycle bits of itself. And in the last decade or so it has become clear that self-eating can also make the difference between health and disease. “Too much or too little autophagy is a problem,” says Daniel Klionsky, a cell biologist at the University of Michigan in Ann Arbor. A cell that bites off more than it can chew can kill itself, Klionsky says. A few rare genetic diseases are linked to an excess of unsuccessful autophagy: The muscles of people with Danon disease, Pompe disease and X-linked myopathy can become weak after filling up with Pac-Man–like structures that put the bite on the cell’s insides but can’t finish digesting. © Society for Science & the Public 2000 - 2011
Related chapters from BP6e: Chapter 11: Motor Control and Plasticity; Chapter 4: The Chemical Bases of Behavior: Neurotransmitters and Neuropharmacology
Related chapters from MM:Chapter 5: The Sensorimotor System; Chapter 4: The Chemistry of Behavior: Neurotransmitters and Neuropharmacology
Link ID: 15110 - Posted: 03.17.2011
by Wendy Zukerman People with Huntington's disease show symptoms more than a decade before they are likely to get a clinical diagnosis. These early effects of the disease don't affect day-to-day functioning, but they will help drug developers evaluate treatments that target the early stages of the disease. Huntington's is a fatal and incurable brain condition whereby a faulty gene makes brain cells commit suicide en masse. It causes problems in communication, mental processes and movement. Within the faulty gene, a specific sequence called CAG is repeated too many times. Although "environmental" factors such as exercise may slow Huntington's progression, the number of CAG repeats accurately predicts the age of illness onset. For example, someone with around 40 repetitions is likely to get their first symptoms in late middle age. Previous studies have found that several years before the disease manifests itself, the brains of people with the mutation undergo subtle changes, with a thinning of the regions involved in motor function. To find out whether how these changes affected people with the Huntington's gene before clinical symptoms begin, Julie Stout of Monash University in Melbourne, Australia, and colleagues selected 119 people who had the gene but no symptoms. The volunteers were predicted to get clinical symptoms around 10 years later, on average, based on their age and number of CAG repeats. © Copyright Reed Business Information Ltd.
Australian researchers studying Huntington's disease in human embryonic stem cells say that signs of the disease can be seen in cells just a few days old. The researchers, from Macquarie University's Australian Proteome Analysis Facility (APAF) and IVF Sydney, say they are the first in the world to study Huntington's disease in human embryonic stem cells. Dr. Leon McQuade, the senior scientific officer at APAF, presented the research Wednesday at the Human Proteomics Organization congress in Sydney. Huntington's disease is a fatal genetic brain disorder affecting about one in every 10,000 Canadians, according to the Huntington Society of Canada. Symptoms are usually first seen in middle age and become progressively worse. Until now, studies into how the disease develops could only be done in mouse models, which do not always accurately reflect the disease in humans, or in brain cells of patients after they have died. Recently, researchers have examined human embryonic stem cells taken from five- to seven-day-old embryos that were known to have Huntington's and had been donated by couples undergoing genetic testing before IVF. © CBC 2010
Steve Connor Huntington’s disease is a relatively rare genetic disorder that you wouldn’t wish upon your worst enemy. If you carry a single copy of the affected gene you are destined to die a horrible death involving uncontrollable movements, psychiatric disturbances and progressive dementia. The first symptoms typically occur around the age of 40, and it takes between 10 and 15 more years for the gradual neurodegeneration to end life. Ten years after the excitement of mapping the human genome, and the revolution in the understanding of genetic disorders that the achievement has brought, it is easy to forget that some of those directly affected by inherited diseases have seen little in terms of practical benefit. The gene involved in Huntington’s disease was mapped to chromosome 4 in 1983 by a team led by Jim Gusella at Harvard Medical School in Boston, but it took another 10 years of intensive effort to isolate and clone the gene itself. This allowed scientists to find the type of changes, or mutations, that cause the disorder – the mutated gene has about two or three times the normal number of ‘GAG repeats. I remember on both occasions – in 1983 and 1993 – there were optimistic predictions that the discoveries would soon lead to a test for the carriers of the Huntington’s mutation and effective treatments – even possibly a cure – for the disease. The sad fact is that although a relatively cheap and accurate diagnostic test for the Huntington’s mutation has existed for some years, this medical advance has for the affected families arguably produced more misery than it has eradicated. For a start, there has been no accompanying revolution in treatment, largely because there are so few affected people (estimated to be about 12,000 in Britain) to make it worth the expense and effort of the drug companies to develop new therapies. ©independent.co.uk
By NICHOLAS BAKALAR George Huntington first described the devastating neurological illness that bears his name in 1872, but The New York Times did not mention it until 1913 — when “Huntington’s chorea” was listed as an item on the agenda of a medical convention in Washington. The name came up again in 1929, but again only in a list of subjects to be discussed at a doctors’ meeting. In 1936, Huntington’s chorea appeared twice, once in each of two 1,000-word letters to the editor whose central subject was eugenics, improving the species by regulating human reproduction. Huntington’s chorea was listed as one of five diseases whose sufferers might be considered candidates for voluntary sterilization. (The others were feeblemindedness of the familial type, schizophrenia, manic-depressive psychosis and epilepsy.) No details about Huntington’s were offered in either letter, and in one of them, written by a doctor in Montclair, N.J., the subheads “Many Defectives” and “Stemming Racial Decay” reveal a sensibility quite different from today’s. Sterilization, the doctor concluded, was “an indispensable part of any farsighted and humanitarian program for dealing with society’s great burden of mental disease, deficiency and dependency.” The first description of the illness appeared on Aug. 9, 1959, in an unsigned article headlined “Report on a Hereditary Illness.” The article described a study of Huntington’s chorea that had been published that month in Psychiatric Bulletin, a British medical journal. Copyright 2009 The New York Times Company
By Tina Hesman Saey Researchers may have discovered how a neuron-killing protein selects its victims — it has an accomplice. Scientists identified a mutant form of the protein huntingtin as the culprit in Huntington’s disease in 1993. The protein is found in every cell in the body, but it only turns deadly in brain cells — particularly cells in the striatum, a part of the brain that helps control movement. Why mutant huntingtin preferentially kills those cells has been a mystery. Now, researchers at Johns Hopkins University in Baltimore report in the June 5 Science that a protein called Rhes may goad huntingtin into killing brain cells in the striatum, leading to Huntington’s disease. If confirmed, the finding could provide new avenues for developing therapies to treat the fatal neurodegenerative disease, says Nancy Wexler, president of the Hereditary Disease Foundation and a Huntington’s disease researcher at Columbia University. “This study really gave me a peek into what the future of the field might look like,” says William Seeley, a neurologist at the University of California, San Francisco’s Memory and Aging Center. Many researchers study the role of individual proteins in causing or preventing disease, but few studies before this one go beyond the molecular level and explain why neurodegenerative diseases attack only certain parts of the brain. “What makes it so special for me is that it builds a bridge back to the anatomy of the disease,” Seeley says. © Society for Science & the Public 2000 - 2009
WASHINGTON - Federal regulators on Friday cleared the first treatment approved in the United States for Huntington’s, a rare inherited disease that causes uncontrolled movements, deterioration of mental abilities and, ultimately, death. The medication, called Xenazine, will not cure the condition—and it has some potentially serious side effects, such as raising the risk of suicidal behavior. However, it does provide relief for a major disabling symptom of Huntington’s: the jerky, involuntary movements known by the medical term chorea and force many patients to live as shut-ins. “A lot of patients won’t go out because they are embarrassed by those movements,” said Dr. Frederick J. Marshall, a University of Rochester Medical Center neurologist who led the clinical study that provided evidence of the drug’s effectiveness. “Suppressing those movements means a lot to people with Huntington’s disease.” The disease affects only about 30,000 patients in the United States. Developing and testing medications for such a small population is a difficult process, with uncertain financial rewards. So the Food and Drug Administration granted Xenazine a special “orphan drug” designation that provides additional years of patent protection and allows the manufacturer, Prestwick Pharmaceuticals, to write off some development costs. The medication had already been approved in Canada, Europe and Australia. © 2008 The Associated Press.
Researchers at Rush University Medical Center, Chicago, and Ceregene Inc., San Diego, have successfully used gene therapy to preserve motor function and stop the anatomic, cellular changes that occur in the brains of mice with Huntington’s disease (HD). This is the first study to demonstrate that, using this delivery method, symptom onset might be prevented in HD mice with this treatment. Results of the study were published in the Proceedings of the National Academy of Sciencesof the United States, June 13, 2006. “This could be an important step toward a disease modifying therapy,” says co-author Jeffrey H. Kordower, Ph.D., director of the Research Center for Brain Repair at Rush. “We could potentially be stopping the disease process in its tracks, delaying symptoms from ever showing up.” Huntington's disease is an inherited degenerative disease that progressively robs patients of the ability to think, judge appropriately, control their emotions and perform coordinated tasks. HD typically begins in mid-life, between the ages of 40 and 50. There is no effective treatment or cure for this fatal illness that affects 30,000 Americans and places another 75,000 at risk. Kordower says this research, if eventually applied to humans, could help those who have HD or, due to the presence of a genetic test, are known to be destined to get HD. © Rush University Medical Center,
Peter Aldhous Huntington’s disease may be about to meet its match with the development of a therapy designed to knock out production of the defective protein that causes the condition. Huntington’s is an untreatable inherited disease in which repetitive sequences of DNA lead to the production of a faulty version of a protein called huntingtin, giving it multiple copies of the amino acid glutamine. As adults, its victims lose their cognitive abilities, suffer involuntary movements and, after a decade or more, die. This week at the American Society of Gene Therapy meeting in Baltimore, Maryland, researchers led by Beverly Davidson of the University of Iowa described their progress treating the disease with a technique called RNA interference, or RNAi. RNAi uses short sequences of RNA just over 20 bases long to trigger a natural “gene-silencing” mechanism, shutting down the production of specific proteins by targeting the RNA that carries the instructions for making them. Last year, Davidson raised the hopes of people carrying the Huntington’s gene when she used engineered viruses to treat mice with the mutated gene. The viruses produce “small interfering” RNA sequences designed to block the RNA carrying the message to make huntingtin. © Copyright Reed Business Information Ltd.
RESTON, Va.—Using both brain function (PET) and anatomical structure (MR) imaging studies, Italian researchers—within the context of an Italian-British collaboration—discovered that degenerative and dysfunctional events occur in individuals many years before the onset of Huntington’s disease—particularly in the brain’s white matter—an area not previously considered primarily involved with the disease. In fact, the brain’s white matter “progressively reduced” as individuals approached the first disease symptoms, according to a study published in February’s Journal of Nuclear Medicine. “Our observations—made by analyzing the results of the largest group of subjects studied to date—may suggest new methodologies and drug trials for therapy,” said Ferdinando Squitieri, M.D., Ph.D., who works in the Neurogenetics Unit and Centre for Rare Diseases of IRCCS Neuromed in Pozzilli, Isernia, Italy. “It is possible to approach the disease at the presymptomatic stage by monitoring the brain tissue volumes and the basal ganglia and cortex dysfunction. If so, we may be able to prevent Huntington’s disease before onset symptoms by using proper drugs,” added the co-author of “Brain White-Matter Volume Loss and Glucose Hypometabolism Precede the Clinical Symptoms of Huntington’s Disease.” Copyright © 2006 SNM
Related chapters from BP6e: Chapter 11: Motor Control and Plasticity; Chapter 2: Functional Neuroanatomy: The Nervous System and Behavior
Related chapters from MM:Chapter 5: The Sensorimotor System; Chapter 2: Cells and Structures: The Anatomy of the Nervous System
Link ID: 8545 - Posted: 06.24.2010
The medication tetrabenazine cut down involuntary movement in patients with Huntington’s disease on average by about 25 percent, with many patients experiencing a greater improvement, according to a study in the February 14 issue of the journal Neurology. Overall, patients who received the medication were six times as likely to be considered by their doctors to have improved considerably, compared to participants who received a placebo. Dr. Kathleen M. Shannon, neurologist and Huntington’s disease specialist at the Huntington’s Disease Society of America Center of Excellence at Rush University Medical Center, led the Rush study. Rush was one of 16 sites to participate in the randomized, controlled study which involved 84 patients. Tetrabenazin is available in Europe and Canada – but not the United States, but is currently being reviewed by the U.S. Food and Drug Administration. If approved, the medication would be the first authorized by the agency expressly for the treatment of Huntington’s disease, which affects about 30,000 people in the United States. “Huntington’s disease is an inherited brain disorder that causes patients to experience uncontrollable jerky movements (chorea), as well as changes in personality, behavior, thinking and memory. There are no FDA-approved treatments for the chorea. Anti-psychotic drugs like haloperidol (Haldol) are commonly used to suppress chorea, but they cause many different side effects. This study shows that tetrabenazine can decrease chorea, and the drug is well-tolerated by most research subjects,” said Shannon. ©2004 Rush University Medical Center,
Gene therapy succeeds in mice with brain disease. ERIKA CHECK Gene therapy could ease the symptoms of some devastating brain disorders, according to evidence presented to US conference last week. Many neurodegenerative diseases are caused when the brain makes mutant proteins that build up in the brain, causing gradually worsening symptoms. These brain-wasting diseases are devastating and incurable. They include Huntington’s disease, which affects around 250,000 people in the United States. Beverley Davidson of the University of Iowa in Iowa City and her colleagues hope that gene therapy will help treat such diseases. The approach involves trying to correct genetic abnormalities by injecting an animal or person with corrective sequences of DNA or RNA. The researchers tested their therapy in mice with a disorder that mimics a disease called spinocerebellar ataxia type 1, which leaves sufferers progressively less able to walk. The therapy eliminated pockets of damaged brain tissue from the mice and corrected the physical symptoms of the disease. © Nature News Service / Macmillan Magazines Ltd 2004
WASHINGTON, DC – Staying physically or mentally active can slow down chemical changes in the brain that lead to the neurodegeneration of Huntington’s disease, researchers show in a mouse model of the disorder. Levels of brain-derived neurotrophic factor (BDNF) stop declining when Huntington’s disease transgenic mice are housed in an enriched environment, the scientists say. BDNF promotes neuron growth and survival and can also regulate communication between neurons. “The finding that environmental enrichment increases BDNF, and that this slows disease progression, provides a potential mechanism for the effects of environmental enrichment on Huntington’s disease,” says M. Flint Beal, chair of neurology at Cornell University Medical College in New York. Copyright © 2004 Society for Neuroscience
DALLAS –- A test using cultured cells provides an effective way to screen drugs against Huntington's disease and shows that two compounds – memantine and riluzole – are most effective at keeping cells alive under conditions that mimic the disorder, UT Southwestern Medical Center researchers report. "These drugs have been tested in a variety of Huntington's disease models and some HD human trials and results are very difficult to interpret," said Dr. Ilya Bezprozvanny, associate professor of physiology and senior author of the study, available online and published in today's issue of Neuroscience Letters. "For some of these drugs conflicting results were obtained by different research groups, but it is impossible to figure out where the differences came from because studies were not conducted in parallel. "We systematically and quantititatively tested the clinically relevant drugs side-by-side in the same HD model. That has never been done before," said Dr. Bezprozvanny. Huntington's disease is a fatal genetic disorder, manifesting in adulthood, in which certain brain cells die. The disease results in uncontrolled movements, emotional disturbance and loss of mental ability. The offspring of a person with Huntington's have a 50 percent chance of inheriting it. More than 250,000 people in the United States have the disorder or are at risk for it. There is no cure, but several drugs are used or are being tested to relieve symptoms or slow Huntington's progression.