March 19, 2012
Investigators at Nationwide Children’s Hospital, working with the DNA Sequencing Core Facility at the University of Utah, have developed an approach to newborn screening (NBS) for the life-threatening genetic disorder, Duchenne muscular dystrophy (DMD) and potentially other muscular dystrophies. As a model for NBS, the approach published online in January in the Annals of Neurology provides evidence that this approach could be implemented if approved by regulatory bodies at a state level or alternatively through the Secretary’s Advisory Committee on Heritable Disorders in Newborns and Children.
DMD is the most common, severe childhood form of muscular dystrophy, inherited as an X-linked recessive disorder. Progressive muscle weakness with loss of ambulation by 12-to-13 years of age is the expected outcome. Heart involvement is significant and may require treatment to avert premature death. On average, patients are diagnosed with DMD at 5 years of age, although parents often notice impaired motor skills at an earlier age.
Over the last three decades, creatine kinase (CK) testing on dried blood spots has been attempted as a method for newborn screening for DMD. CK is an enzyme that leaks into the blood from damaged muscle cells; it is markedly elevated in DMD and some other muscular dystrophies. Using CK testing on dried blood spots derived from heel-sticks to identify DMD cases during the newborn period was validated in 1979 and launched a pathway for this method of testing at birth. If CK was elevated, it was repeated at four to six weeks of age on venous blood obtained in the doctor’s office. If elevation persisted, blood was again taken and DNA was isolated from white blood cells and tested for DMD mutations to establish a definitive diagnosis. This three-step screening process took shape in New Zealand and spread to programs in Edinburgh, Germany, Canada, France, Wales, Cyprus and Belgium and Western Pennsylvania. The longest running DMD newborn screening program in history, in Wales, recently closed. To this day, Antwerp, Belgium is home to the only program that maintains newborn screening for DMD.
"The three-step model is poorly adapted to newborn screening in the USA," said Jerry R. Mendell, MD, principal investigator of the study and current director of the Center for Gene Therapy at The Research Institute at Nationwide Children’s Hospital. "It can work efficiently in a publically-funded health care system where newborn care is designated at specific times post-delivery making follow-up blood draws a realistic part of the total program for child welfare." In the USA, mother and child are discharged within 24 to 48 hours following uncomplicated deliveries and post-natal care cannot be enforced. Thus, many newborns with elevated CKs at birth would be lost to follow up.
The two-tier system developed by Dr. Mendell permits heel blood taken at birth to be tested initially for CK with follow up DNA testing for DMD. A CK is obtained on the dried blood spot and if the level exceeds a predetermined threshold, DNA testing is automatically done from the same sample. No follow up blood samples are required. “This two-tier system (CK and DNA testing on same sample) is practical, comprehensive, and cost effective,” said Dr. Mendell, who is also a faculty member in The Ohio State University College of Medicine.
Promising new DMD therapies have rekindled interest in establishing a pathway for newborn screening in the DMD patient population. In 2004, Center for Disease Control workshop participants concluded that early diagnosis of DMD could have potential advantages for families, considering multiple treatment strategies were on the horizon. Funds were made available to Dr. Mendell and his team at Nationwide Children’s Hospital to explore the feasibility for establishing a model for DMD newborn screening in the United States.
The study appearing in Annals of Neurology documents a nearly-four-year pilot study of a voluntary DMD newborn screening program in Ohio. Over the course of the study, 37,749 newborn boys were screened and six were discovered to have DMD gene mutations. In cases where CK was elevated and DMD mutations were not found, the investigators extended the study to identify limb-girdle muscular dystrophy (LGMD) gene mutations as part of the screening process. The published study results confirmed that this was possible and reported that three of the cases had gene mutations found in LGMD.
"The program we have introduced differs from past programs and the current Antwerp approach to newborn screening for DMD that require a three-step process," said Dr. Mendell. "This new process fits current U.S. obstetrics practices and allows us to readily distinguish false and true positive test results."
Whether DMD treatment has advanced to the point of justifying newborn screening is a judgment yet to be made by state and federal agencies. “If and when an early therapy that improves the health outcome for individuals with DMD becomes available, our study serves as a model for implementation of newborn screening for DMD,” said Dr. Mendell.
Provided by Nationwide Children’s Hospital
Source: medicalxpress.com
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ScienceDaily (Mar. 19, 2012) — Researchers from Chalmers and the University of Gothenburg have shown that nanocellulose stimulates the formation of neural networks. This is the first step toward creating a three-dimensional model of the brain. Such a model could elevate brain research to totally new levels, with regard to Alzheimer’s disease and Parkinson’s disease, for example.
Nerve cells growing on a three-dimensional nanocellulose scaffold. One of the applications the research group would like to study is destruction of synapses between nerve cells, which is one of the earliest signs of Alzheimer’s disease. Synapses are the connections between nerve cells. In the image, the functioning synapses are yellow and the red spots show where synapses have been destroyed. (Credit: Illustration: Philip Krantz, Chalmers)
Over a period of two years the research group has been trying to get human nerve cells to grow on nanocellulose.
"This has been a great challenge," says Paul Gatenholm, Professor of Biopolymer Technology at Chalmers.‟Until recently the cells were dying after a while, since we weren’t able to get them to adhere to the scaffold. But after many experiments we discovered a method to get them to attach to the scaffold by making it more positively charged. Now we have a stable method for cultivating nerve cells on nanocellulose."
When the nerve cells finally attached to the scaffold they began to develop and generate contacts with one another, so-called synapses. A neural network of hundreds of cells was produced. The researchers can now use electrical impulses and chemical signal substances to generate nerve impulses, that spread through the network in much the same way as they do in the brain. They can also study how nerve cells react with other molecules, such as pharmaceuticals.
The researchers are trying to develop ‟artificial brains,” which may open entirely new possibilities in brain research and health care, and eventually may lead to the development of biocomputers. Initially the group wants to investigate destruction of synapses between nerve cells, which is one of the earliest signs of Alzheimer’s disease. For example, they would like to cultivate nerve cells and study how cells react to the patients’ spinal fluid.
In the future this method may be useful for testing various pharmaceutical candidates that could slow down the destruction of synapses. In addition, it could provide a better alternative to experiments on animals within the field of brain research in general.
The ability to cultivate nerve cells on nanocellulose is an important step ahead since there are many advantages to the material.
‟Pores can be created in nanocellulose, which allows nerve cells to grow in a three-dimensional matrix. This makes it extra comfortable for the cells and creates a realistic cultivation environment that is more like a real brain compared with a three-dimensional cell cultivation well,” says Paul Gatenholm.
Paul Gatenholm says that there are a number of new biomedical applications for nanocellulose. He is currently also leading other projects that use the material, for example a project where researchers are using nanocellulose to develop cartilage to create artificial outer ears. His research group has previously developed artificial blood vessels made of nanocellulose, which are being evaluated in pre-clinical studies.
Research on new application areas for nanocellulose is of major strategic significance for Sweden. Several projects are financed by the Knut and Alice Wallenberg Foundation and being conducted in collaboration between Chalmers and KTH within the Wallenberg Wood Science Center, WWSC.
Facts about nanocellulose: Nanocellulose is a material that consists of nanosized cellulose fibers. Typical dimensions are widths of 5 to 20 nanometers and lengths of up to 2,000 nanometers. Nanocellulose can be produced by bacteria that spin a close-meshed structure of cellulose fibers. It can also be isolated from wood pulp through processing in a high-pressure homogenizer.
Source: Science Daily
Filed under science neuroscience brain psychology disease
March 16, 2012 By Anne Trafton
Alan Jasanoff. Credit: Allegra Boverman
After finishing his PhD in molecular biophysics, Alan Jasanoff decided to veer away from that field and try looking into some of the biggest questions in neuroscience: How do we perceive things? What happens in our brains when we make decisions?
After a few months, however, he realized that he didn’t have the tools he wanted to use — so he decided to start making his own.
Jasanoff, who recently earned tenure in MIT’s Department of Biological Engineering, now specializes in developing novel brain-imaging agents that can reveal information more detailed than other human brain-imaging techniques such as fMRI and PET, and more comprehensive than traditional neuroscience measurements such as microscopy and electrode recordings. With the new tools, he is also beginning to explore some of the fundamental questions that first drew him into neuroscience.
Neuroscientists commonly use fMRI, which measures blood flow in the brain, as a proxy for neural activity. In the past several years, Jasanoff has developed sensors that can be used with fMRI to image brain activity more directly, by measuring levels of neurotransmitters (the chemicals that carry messages between neurons) and calcium, which enters neurons when they fire.
Using those sensors, Jasanoff has started exploring how positive reinforcement influences behavior and decision making in animals. His work could also be applicable to fields outside of neuroscience, because intracellular signaling molecules such as calcium “are really ubiquitous — not just in neuronal signaling but signaling throughout the body, during development, immune-cell activity and so on,” says Jasanoff, who is an associate member of MIT’s McGovern Institute for Brain Research and an associate professor of biological engineering, nuclear science and engineering, and brain and cognitive sciences.
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March 16, 2012
MRI brain scan
Distinct patterns of activity— which may indicate a predisposition to care for infants — appear in the brains of adults who view an image of an infant face — even when the child is not theirs, according to a study by researchers at the National Institutes of Health and in Germany, Italy, and Japan.
Seeing images of infant faces appeared to activate in the adult’s brains circuits that reflect preparation for movement and speech as well as feelings of reward.
The findings raise the possibility that studying this activity will yield insights into care giving behavior, but also in cases of child neglect or abuse.
"These adults have no children of their own. Yet images of a baby’s face triggered what we think might be a deeply embedded response to reach out and care for that child," said senior author Marc H. Bornstein, Ph.D., head of the Child and Family Research Section of the Eunice Kennedy Shriver National Institute of Child Health and Human Development, the NIH institute that collaborated on the study.
While the researchers recorded participants’ brain activity, the participants did not speak or move. Yet their brain activity was typical of patterns preceding such actions as picking up or talking to an infant, the researchers explained. The activity pattern could represent a biological impulse that governs adults’ interactions with small children.
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March 15th, 2012
Researchers have identified the first gene mutation associated with a chronic and often fatal form of neuroblastoma that typically strikes adolescents and young adults. The finding provides the first clue about the genetic basis of the long-recognized but poorly understood link between treatment outcome and age at diagnosis.
The study involved 104 infants, children and young adults with advanced neuroblastoma, a cancer of the sympathetic nervous system. Investigators discovered the ATRX gene was mutated only in patients age 5 and older. The alterations occurred most often in patients age 12 and older. These older patients were also more likely than their younger counterparts to have a chronic form of neuroblastoma and die years after their disease is diagnosed.
The findings suggest that ATRX mutations might represent a new subtype of neuroblastoma that is more common in older children and young adults. The work is from the St. Jude Children’s Research Hospital – Washington University Pediatric Cancer Genome Project (PCGP). The study appears in the March 14 edition of the Journal of the American Medical Association.
If validated, the results may change the way doctors think about this cancer, said co-author Richard Wilson, PhD, director of The Genome Institute at Washington University School of Medicine in St. Louis.
“This suggests we may need to think about different treatment strategies for patients depending on whether or not they have the ATRX mutation,” he says.
Neuroblastoma accounts for 7 percent to 10 percent of all childhood cancers and about 15 percent of pediatric cancer deaths. In about 50 percent of patients, the disease has already spread when the cancer is discovered.
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March 15, 2012
In Batten disease, a rare but fatal neurodegenerative disorder in infants and children, proteins (shown in pink) accumulate in the brain and contribute to mental decline, paralysis and seizures. In mice with the infantile form of the disease, combination treatment with gene therapy and bone marrow transplantation reduced the buildup of proteins, dramatically increasing life span and improving motor function. Credit: Mark Sands, Ph.D
Infants with Batten disease, a rare but fatal neurological disorder, appear healthy at birth. But within a few short years, the illness takes a heavy toll, leaving children blind, speechless and paralyzed. Most die by age 5.
There are no effective treatments for the disease, which can also strike older children. And several therapeutic approaches, evaluated in mouse models and in young children, have produced disappointing results.
But now, working in mice with the infantile form of Batten disease, scientists at Washington University School of Medicine in St. Louis and Kings College London have discovered dramatic improvements in life span and motor function by treating the animals with gene therapy and bone marrow transplants.
The results are surprising, the researchers say, because the combination therapy is far more effective than either treatment alone. Gene therapy was moderately effective in the mice, and bone marrow transplants provided no benefit, but together the two treatments created a striking synergy.
The research is online in the Annals of Neurology.
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Stem Cells Hint at Potential Treatment for Huntington’s Disease
Huntington’s disease, the debilitating congenital neurological disorder that progressively robs patients of muscle coordination and cognitive ability, is a condition without effective treatment, a slow death sentence.
But if researchers can build on new research reported this week (March 15, 2012) in the journal Cell Stem Cell, a special type of brain cell forged from stem cells could help restore the muscle coordination deficits that cause the uncontrollable spasms characteristic of the disease.
“This is really something unexpected,” says Su-Chun Zhang, a University of Wisconsin-Madison neuroscientist and the senior author of the new study, which showed that locomotion could be restored in mice with a Huntington’s-like condition.
Zhang is an expert at making different types of brain cells from human embryonic or induced pluripotent stem cells. In the new study, his group focused on what are known as GABA neurons, cells whose degradation is responsible for disruption of a key neural circuit and loss of motor function in Huntington’s patients. GABA neurons, Zhang explains, produce a key neurotransmitter, a chemical that helps underpin the communication network in the brain that coordinates movement.
In the laboratory, Zhang and his colleagues at the UW-Madison Waisman Center have learned how to make large amounts of GABA neurons from human embryonic stem cells, which they sought to test in a mouse model of Huntington’s disease. The goal of the study, Zhang notes, was simply to see if the cells would safely integrate into the mouse brain. To their astonishment, the cells not only integrated but also project to the right target and effectively reestablished the broken communication network, restoring motor function.
The results of the study were surprising, Zhang explains, because GABA neurons reside in one part of the brain, the basal ganglia, which plays a key role in voluntary motor coordination. But the GABA neurons exert their influence at a distance on cells in the midbrain through the circuit fueled by the GABA neuron chemical neurotransmitter.
“This circuitry is essential for motor coordination,” Zhang says, “and it is what is broken in Huntington patients. The GABA neurons exert their influence at a distance through this circuit. Their cell targets are far away.”
That the transplanted cells could effectively reestablish the circuit was completely unexpected: “Many in the field feel that successful cell transplants would be impossible because it would require rebuilding the circuitry. But what we’ve shown is that the GABA neurons can remake the circuitry and produce the right neurotransmitter.”
The implications of the new study are important not only because they suggest it may one day be possible to use cell therapy to treat Huntington’s, but also because it suggests the adult brain may be more malleable than previously believed.
The adult brain, notes Zhang, is considered by neuroscientists to be stable, and not easily susceptible to therapies that seek to correct things like the broken circuits at the root of conditions like Huntington’s. For a therapy to work, it has to be engineered so that only cells of interest are affected. “The brain is wired in such a precise way that if a neuron projects the wrong way, it could be chaotic.”
Zhang stresses that while the new research is promising, working up from the mouse model to human patients will take much time and effort. But for a disease that now has no effective treatment, the work could become the next best hope for those with Huntington’s.
Article by Terry Devitt
Source: Neuroscience News
Filed under science neuroscience psychology brain disease
Sex-Deprived Fruit Flies Turn to Alcohol, Perhaps to Fulfill a Physiological Demand for a Reward
ScienceDaily (Mar. 15, 2012) — After being deprived of sex, male fruit flies, known as Drosophila melanogaster, may turn to alcohol to fulfill a physiological demand for a reward, according to a study recently published in the journal Science. Troy Zars, an associate professor of biological sciences at the University of Missouri and neurobiology expert, said that understanding why rejected male flies find solace in ethanol could help treat human addictions.
"Identifying the molecular and genetic mechanisms controlling the demand for reward in fruit flies could potentially influence our understanding of drug and alcohol abuse in humans, since previous studies have detailed similarities between signaling pathways in fruit flies and mammals," Zars said.
In the study, male fruit flies that had mated repeatedly for several days showed no preference for alcohol-spiked food. On the other hand, spurned males and those denied access to females strongly preferred food mixed with 15 percent alcohol. The researchers believed the alcohol may have satisfied the flies’ desire for physical reward.
Zars said the new discovery could lead to greater understanding of the relationship between the social and physical causes of substance abuse in humans.
"The authors provide new insights into a neural circuit that links a rewarding social interaction with a lasting change in behavior preference," Zars said.
Source: Science Daily
Filed under science neuroscience psychology
ScienceDaily (Mar. 15, 2012) — Odds are, you’re not going to make it all the way through this article without thinking about something else. In fact, studies have found that our minds are wandering half the time, drifting off to thoughts unrelated to what we’re doing — did I remember to turn off the light? What should I have for dinner?
Odds are, you’re not going to make it all the way through this article without thinking about something else. In fact, studies have found that our minds are wandering half the time, drifting off to thoughts unrelated to what we’re doing — did I remember to turn off the light? What should I have for dinner? (Credit: © Yuri Arcurs / Fotolia)
A new study investigating the mental processes underlying a wandering mind reports a role for working memory, a sort of a mental workspace that allows you to juggle multiple thoughts simultaneously.
Imagine you see your neighbor upon arriving home one day and schedule a lunch date. On your way to add it to your calendar, you stop to turn off the drippy faucet, feed the cat, and add milk to your grocery list. The capacity that allows you to retain the lunch information through those unrelated tasks is working memory.
The new study, published online March 14 in the journal Psychological Science by Daniel Levinson and Richard Davidson at the University of Wisconsin-Madison and Jonathan Smallwood at the Max Planck Institute for Human Cognitive and Brain Science, reports that a person’s working memory capacity relates to the tendency of their mind to wander during a routine assignment. Lead author Levinson is a graduate student with Davidson, a professor of psychology and psychiatry, in the Center for Investigating Healthy Minds at the UW-Madison Waisman Center.
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ScienceDaily (Mar. 14, 2012) — The meal is pushed way, untouched. Loss of appetite can be a fleeting queasiness or continue to the point of emaciation. While it’s felt in the gut, more is going on inside the head.
New findings are emerging about brain and body messaging pathways that lead to loss of appetite, and the systems in place to avoid starvation.
Today, scientists report in Nature about a brain circuit that mediates the loss of appetite in mice. The researchers also discovered potential therapeutic targets within the pathway. Their experimental results may be valuable for developing new treatments for a variety of eating disorders. These include unrelenting nausea, food aversions, and anorexia nervosa, a condition in which a person no longer wants to eat enough to maintain a normal weight.
The senior author of the paper is Dr. Richard D. Palmiter, University of Washington professor of biochemistry and an investigator with the Howard Hughes Medical Institute. His co-authors are Dr. Qi Wu, formerly of the UW and now at the Eagles Diabetes Research Center and Department of Pharmacology at Carver College of Medicine, University of Iowa, and Dr. Michael S. Clark of the UW Department of Psychiatry and Behavioral Sciences. Palmiter is known for co-developing the first transgenic mice in the 1980s with Dr. Ralph Brinster at the University of Pennsylvania. His more recent studies are of chemicals that nerve cells use to communicate with each other, their roles in mouse brain development and function, and their relation to behavior.
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