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October 16, 2008, 11:01 PM CT

When a light goes on during thought processes

When a light goes on during thought processes
Individual and double action potentials can be recorded optically using a genetic calcium indicator that colours the cells in the brain of a living mouse.

Image: Max Planck Institute for Medical Research
A nerve cell is a major hub for the exchange of valuable information. The nose, eyes, ears, and other sense organs perceive our environment through various antennae known as receptors. The numerous stimuli are then passed on to the neurons. All of this information is collected, processed, and finally transferred to specific brain centers at these hubs - the human brain consists of almost 100 billion nerve cells. The nerve cell uses a special means of transport for this purpose: the action potential which codes the information, thus enabling communication between the nerve cells.

Calcium as the starting gun.

An action potential of this kind is an electrical excitation and arises when our nerve cells receive the information via a stimulus: the voltage across the cell membrane of the neuron changes and various ion channels open and close in a very specialized manner. Shortly before the nerve cell forwards the information via the stimulus, calcium ions pour into the nerve cell, acting as the starting gun for the flow of data from one neuron to the next.

In the past, action potential was measured and rendered visible using microelectrodes. However, this method only enabled the monitoring of a limited number of cells engaged in the process of communication. Moreover, researchers were unable to record neuronal communication in a clearly identifiable way over a longer period or in freely moving animals using this method.........

Posted by: Daniel      Read more         Source


October 14, 2008, 7:52 PM CT

Researchers continue to find genes for type 1 diabetes

Researchers continue to find genes for type 1 diabetes
Genetics scientists have identified two novel gene locations that raise the risk of type 1 diabetes. As they continue to reveal pieces of the complicated genetic puzzle for this disease, the scientists expect to improve predictive tests and devise preventive strategies.

"As we add to our knowledge of the biology of type 1 diabetes and better understand details of the disease's genetic risk, we will be able to develop better diagnostic tests that meaningfully predict who will develop diabetes," said study leader Hakon Hakonarson, M.D., Ph.D., director of the Center for Applied Genomics at The Children's Hospital of Philadelphia.

The study appeared online Oct. 7 in Diabetes, the journal of the American Diabetes Association. Hakonarson's co-leader in the study was Constantin Polychronakos, M.D., director of Pediatric Endocrinology at McGill University in Montreal.

Type 1 diabetes, formerly called juvenile diabetes, commonly begins in childhood, when the body's immune system malfunctions and destroys insulin-producing beta cells in the pancreas. Without insulin, blood sugar levels run out of control and can impair blood flow and damage the eyes, nerves and kidneys. It is second only to asthma as the most common chronic disease in American children. Patients are dependent for life on insulin injections or insulin medications.........

Posted by: JoAnn      Read more         Source


October 8, 2008, 9:59 PM CT

Human Mind and Future Infrastructure Systems

Human Mind and Future Infrastructure Systems
The National Science Foundation (NSF) Office of Emerging Frontiers in Research and Innovation (EFRI) has announced 12 grants for fiscal year 2008, awarding a total of $23,779,056 over four years to 54 researchers representing 20 institutions.

Interdisciplinary teams will pursue transformative, fundamental research in two areas of great promise: understanding the brain and how its abilities may be used through cognitive optimization and prediction; and developing ways to make complex, interdependent infrastructure systems more resilient and sustainable.

What scientists learn from the brain may open a number of new paths of discovery, in areas such as computing, robotics, medicine and education. Understanding how the brain moves the hand, for example, could illuminate entirely novel ways to help people who are paralyzed or use prosthetic limbs. Understanding how the brain visually recognizes objects will enable advances in artificial vision systems, robotic intelligence and more.

The second area of research will examine complex challenges in our nation's interwoven infrastructures as demands on these interdependent systems are changing. Scientists will investigate how to increase their resiliency and sustainability as, for example, numerous electric vehicles interact with the power grid. In addition to drawing electricity from the grid, electric vehicles may send stored energy to the grid. New research may find a role for these vehicles in stabilizing the electric power grid during a catastrophe and in managing fluctuations in electricity from renewable energy sources.........

Posted by: Scott      Read more         Source


October 8, 2008, 9:36 PM CT

Proteins in sperm unlock understanding infertility

Proteins in sperm unlock understanding infertility
Proteins found in sperm are central to understanding male infertility and could be used to determine new diagnostic methods and fertility therapys as per a paper published by the journal Molecular and Cellular Proteomics (MCP). The article demonstrates how proteomics, a relatively new field focusing on the function of proteins in a cell, can be successfully applied to infertility, helping identify which proteins in sperm cells are dysfunctional.

"Up to 50 percent of male-factor infertility cases in the clinic have no known cause, and therefore no direct therapy. In-depth study of the molecular basis of infertility has great potential to inform the development of sensitive diagnostic tools and effective therapies," write co-authors Diana Chu, assistant professor of biology at San Francisco State University and Tammy Wu, post-doctoral fellow at SF State. The study is included in a special Oct. 10 issue of MCP dedicated to the clinical application of proteomics.

"We suggest how the study of proteins is useful in the clinic, to help people move from infertile to fertile and ultimately to help couples have a baby," Chu said. "The ultimate goal is that a doctor could be able to say to a patient, 'this is the protein that is misregulated in your sperm and this is the drug that corrects it or decreases the level of that protein.' Understanding sperm proteins also means that a doctor could be able to inform patients of the likely success rates of different fertility therapies, an important factor given the high cost of fertility therapys".........

Posted by: Scott      Read more         Source


October 7, 2008, 10:50 PM CT

Atomic-resolution views suggest function of enzyme

Atomic-resolution views suggest function of enzyme
Iris of Eye with Model of GAF Domain

Image of the iris of researcher Clemens Heikaus' eye with a model of a GAF domain imbedded in the pupil. A messenger molecule binds to the GAF domain to regulate an enzyme, PDE6, that is central to the way light hitting the retina is converted to signals to the brain.

Credit: Brad Clifton
An atomic-resolution view of an enzyme found only in the eye has given scientists at the University of Washington (UW) clues about how this enzyme, essential to vision, is activated. The enzyme, phosphodiesterase 6 (PDE6), is central to the way light entering the retina is converted into a cascade of signals to the brain.

This particular form of the enzyme comes from the cone photoreceptors of the retina and has not been well-researched, in contrast to its rod form. Rods are involved in night vision and motion sensation; the cones are responsible for color sensitivity, visual acuity, daylight vision, and adjustment to bright light.

The section of the enzyme molecule that most interests the scientists is the so-called GAF A domain. A small messenger molecule, cGMP, binds to the GAF A domain to regulate the enzyme.

"The domain binds to this small molecule with extremely high sensitivity," said UW biochemist Clemens Heikaus, who along with Sergio E. Martinez, now a research associate at Rutgers, carried out the study. "From our structure, we can infer why it prefers cGMP over other messenger molecules." He added that the domain is quick in recognizing and responding to the messenger molecule to create an instantaneous flow of information to the brain.........

Posted by: Mike      Read more         Source


October 6, 2008, 10:28 PM CT

Why current publication practices may distort science

Why current publication practices may distort science
The current system of publishing medical and scientific research provides "a distorted view of the reality of scientific data that are generated in the laboratory and clinic," says a team of scientists in this week's PLoS Medicine

In their Essay, Neal Young (National Institutes of Health, USA), John Ioannidis (Tufts University School of Medicine, USA and University of Ioannina School of Medicine, Greece), and Omar Al-Ubaydli (George Mason University, USA) apply principles from the field of economics to present evidence consistent with a distortion.

There is an "extreme imbalance," they say, between the abundance of supply (the output of basic science laboratories and clinical investigations) and the increasingly limited venues for publication (journals with sufficiently high impact). The result is that only a small proportion of all research results are eventually chosen for publication, and these results are unrepresentative of scientists' repeated samplings of the real world.

The authors argue that there is a moral imperative to reconsider how scientific data are judged and disseminated.

A prior Essay by one of the co-authors, John Ioannidis, which was entitled "Why most published research findings are false" (http://dx.doi.org/10.1371/journal.pmed.0020124) has been the most viewed PLoS Medicine article of all time and was called "an instant cult classic" in a Boston Globe op-ed of July 27 2006 (http://www.boston.com/news/science/articles/2006/07/27/science_and_shams/).........

Posted by: Janet      Read more         Source


October 3, 2008, 5:27 AM CT

Brain pathway responsible for obesity

Brain pathway responsible for obesity
University of Wisconsin-Madison researchers, for the first time, have found a messaging system in the brain that directly affects food intake and body weight.

Published in the Oct. 3, 2008 issue of Cell, the findings--from a study in mice--point to a entirely new approach to treating and preventing obesity in humans. The discovery also offers hope for new ways to treat related disorders, such as type 2 diabetes and cardiovascular diseases--the most prevalent health problems in the United States and the rest of the developed world.

Led by Dongsheng Cai, an assistant professor of physiology at the UW School of Medicine and Public Health, the scientists looked specifically at the hypothalamus--the brain structure responsible for maintaining a steady state in the body--and for the first time observed that a cell-signaling pathway primarily linked to inflammation also influences the regulation of food intake. Stimulating the pathway led the animals to increase their energy consumption, while suppressing it helped them maintain normal food intake and body weight.

The research stems from recent explorations into the problem called metabolic inflammation, a by-product of too much food or energy consumption. Unlike the classical inflammation typically observed in infections, injuries and diseases such as cancer, the metabolic inflammation seen in obesity-related diseases is much milder, doesn't lead to overt symptoms or cause tissues damage.........

Posted by: JoAnn      Read more         Source


October 1, 2008, 8:40 AM CT

Genes influence effectiveness of weight-loss drug

Genes influence effectiveness of weight-loss drug
Obese patients with a specific genetic make-up lose more weight when taking the weight loss drug sibutramine and undergoing behavioral treatment in comparison to those without this genetic make-up, reports a new study in Gastroenterology, the official journal of the American Gastroenterological Association (AGA) Institute.

The obesity epidemic continues to be an increasingly global problem: an estimated 1.6 billion adults worldwide are overweight (body mass index [BMI]>25) and 400 million are obese (BMI>30). In addition, the incidences of diabetes and other debilitating diseases attributable to obesity continue to rise.

While there are numerous options for the therapy of obesity, this study examined sibutramine, a medicine approved for the long-term therapy of obesity. The drug creates a feeling of fullness, prevents decline in metabolic rate linked to low calorie diets and causes weight loss, particularly when combined with behavioral treatment. However, weight loss with the drug is highly variable. Therefore, a research team at the Mayo Clinic assessed the influence of specific markers of candidate genes controlling serotonergic and adrenergic mechanisms (α2A-receptor, 5-HTTLPR and GNβ3) on weight loss/body composition in response to sibutramine or placebo.........

Posted by: JoAnn      Read more         Source


September 28, 2008, 8:42 PM CT

'Hub' of fear memory formation identified in brain cells

'Hub' of fear memory formation identified in brain cells
A protein mandatory for the earliest steps in embryonic development also plays a key role in solidifying fear memories in the brains of adult animals, researchers have revealed. An apparent "hub" for changes in the connections between brain cells, beta-catenin could be a potential target for drugs to enhance or interfere with memory formation.

The results are published online this week and appear in the recent issue of Nature Neuroscience

The protein beta-catenin acts like a Velcro strap, fastening cells' internal skeletons to proteins on their external membranes that connect them with other cells. In species ranging from flies to frogs to mice, it also can transmit early signals that separate an embryo into front and back or top and bottom.

During long-term memory formation, structural changes take place in the synapses the connections between neurons in the brain, says Kerry Ressler, MD, PhD, associate professor of psychiatry and behavioral sciences at Emory University School of Medicine. Ressler is a researcher at Emory University's Yerkes National Primate Research Center, where the research was conducted, and a Howard Hughes Medical Institute investigator.

"We thought beta-catenin could be a hub for the changes that take place in the synapses during memory formation," says Ressler. "But because beta-catenin is so important during development, we couldn't take the standard approach of just knocking it out genetically".........

Posted by: Daniel      Read more         Source


September 24, 2008, 6:21 PM CT

Balancing the brain

Balancing the brain
Neuroresearchers at Children's Hospital Boston have identified the first known "master switch" in brain cells to orchestrate the formation and maintenance of inhibitory synapses, essential for proper brain function. The factor, called Npas4, regulates more than 200 genes that act in various ways to calm down over-excited cells, restoring a balance that is thought to go askew in some neurologic disorders. The findings are reported in the September 24 advance online edition of the journal Nature

Synapses, the connections between brain cells, can be excitatory or inhibitory in nature. At birth, the rapidly developing brain teems with excitatory synapses, which tend to make nerve cells "fire" and stimulate their neighbors. But if the excitation isn't eventually balanced, it can lead to epilepsy, and diseases like autism and schizophrenia have been linked to an imbalance of excitation and inhibition. The creation of inhibitory connections is also necessary to launch critical periods -- windows of rapid learning during early childhood and adolescence, when the brain is very "plastic" and able to rewire itself.

Npas4 is a transcription factor, a switch that activates or represses other genes. The researchers, led by Michael Greenberg, PhD, director of the Neurobiology Program at Children's, demonstrated that the activity of as a number of as 270 genes changes when Npas4 activity is blocked in a cell, and that Npas4 activation is linked to an increased number of inhibitory synapses on the cell's surface.........

Posted by: Daniel      Read more         Source



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Did you know?
Scientists at Yale have brought to light a mechanism that regulates the way an internal organelle, the Golgi apparatus, duplicates as cells prepare to divide, according to a report in Science Express.Graham Warren, professor of cell biology, and colleagues at Yale study Trypanosoma brucei, the parasite that causes Sleeping Sickness. Like a number of parasites, it is exceptionally streamlined and has only one of each internal organelle, making it ideal for studying processes of more complex organisms that have a number of copies in each cell.

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