Get latest biomedical research news compilation here

Friday, September 25, 2015

Paralyzed Man Walks Again Using Brain-Wave System

"Even after years of paralysis, the brain can still generate robust brain waves that can be harnessed to enable basic walking."

Live Science | By Rachael Rettner @RachaelRettner

A 26-year-old man who was paralyzed in both legs has regained the ability to walk using a system controlled by his brain waves, along with a harness to help support his body weight, a new study says.

In order to walk, the patient wore a cap with electrodes that detected his brain signals. These electrical signals — the same as those a doctor looks at when running an electroencephalogram (EEG) test — were sent to a computer, which "decoded" the brain waves. It then used them to send instructions to another device that stimulated the nerves in the man's legs, causing the muscles to move.

Using this system, the patient, who had been paralyzed for five years after a spinal cord injury, was able to walk about 12 feet (3.66 meters). He used a walker and wore a harness to provide some body-weight support and prevent him from falling.

"Even after years of paralysis, the brain can still generate robust brain waves that can be harnessed to enable basic walking," study co-author Dr. An Do, an assistant professor of neurology at the University of California, Irvine, said in a statement. "We showed that you can restore intuitive, brain-controlled walking after a complete spinal cord injury."

Previously, people have used similar brain-controlled systems (known as brain-computer interfaces) to move limb prostheses, such as a robotic arm. And last year, a paralyzed person used his brain to control an exoskeleton that allowed him to make the first kick of the 2014 World Cup.

The researchers say the new study provides proof of concept that a person with complete paralysis of both legs can use a brain-controlled system to stimulate leg muscles and restore walking.

However, the new report is based on just one patient, so more research is needed to see if other paralyzed patients can benefit from the technology as well, the researchers said.

Still, "the system reported here represents an important step toward the development of technologies that can restore or improve walking in individuals with paraplegia due to [spinal cord injury]," the researchers said.

Before the man could use the system to walk, he first underwent mental training to learn to use his brain waves to control an avatar in virtual reality. He also underwent physical training to strengthen his leg muscles.

Then, the patient used the brain-controlled system to practice walking while he was suspended above ground. After 20 sessions in the suspended system, he was able to practice walking on the ground, the researchers said.

Dr. Elizabeth Tyler-Kabara, an associate professor of neurological surgery and bioengineering at the University of Pittsburgh, who was not involved with the study, said that the work "is another step in demonstrating the feasibility of using brain-computer interfaces to control various devices that already exist."

In the case, the patient was controlling a device known as Parastep, which provides electrical stimulation to leg muscles to facilitate movement.

Typically, patients who use Parastep push a button to send electrical signals to the legs, but in the new study, the control signal came from the EEG. "By coupling two interesting technologies, you end up with something greater than the sum of the two," Tyler-Kabara said.

In the future, it may be possible to implant the entire system inside a patient's body — using implants to the brain, spinal cord and other areas — so that a patient would not need to get in and out of the equipment, the researchers said.

The study is published today (Sept. 23) in the Journal of NeuroEngineering and Rehabilitation.

Source: Huffingtonpost 

Neuronal Connection Between Fat and the Brain Visualized

Researchers pinpoint the neurons within white fat tissue that mediate brain-bound leptin signaling and eventual fat breakdown.

The hormone leptin, produced by fat cells, acts as a satiety signal to the brain, resulting in fat breakdown when levels are high. The hormone, present in proportion to the amount of fat tissue, is known to act on hypothalamic neurons in the brain to tell an animal when it’s full and to kick-start the breakdown of fat. Now, a team led by researchers at the Instituto Gulbenkian de Ciencia (IGC) in Portugal and the Rockefeller University in New York City have, for the first time, provided direct visual evidence that some sympathetic neurons from the brain indeed terminate within fat cells. The researchers also used optogenetics to stimulate these neurons within a fat pad in mice and cause the breakdown of fat. Their results were published today (September 24) in Cell.
“This is a very comprehensive study with quite a beautiful dataset,” saidStephanie Fulton, who studies the neural pathways of food-motivated behavior at the University of Montreal in Canada and was not involved in the work. “[The authors] took advantage of powerful techniques to solidify the strong suggestion that white adipose tissue is directly innervated by the central nervous system and clearly demonstrate that leptin activates this sympathetic input.”
“It’s a real tour de force that combines really modern optogenetic and tissue clearing approaches that are being developed to understand the central nervous system [CNS] and are here applied to understand the neural action outside the CNS and in the body,” said Paul Kenny, director of the Experimental Therapeutics Institute at Mount Sinai Hospital in New York who was also not involved in the study.
Previous studies using neuronal tracing methods provided indirect evidence that neurons should be found within white fat tissue because they could not distinguish between neurons that were just passing through the tissue and those that had axon terminals within adipocytes themselves. Nor was there direct evidence for the function of these neurons in fat breakdown.
In the current work, Ana Domingos of the IGC and her colleagues first visualized the 3-D anatomy and structure of a dissected mouse fat pad using an ex vivo optical tomography technique. The fat organ was first made transparent by removal of the fat which leaves behind the extracellular matrix, vasculature, and neural structures. “Adipose tissue is an organ but the only image we have of it is as a blob,” said Domingos. “I wondered what the blob looks like from the inside, if there is there an anatomical complexity that may give us insight into the physiology of the organ.”
The team found axon bundles penetrating the organ. Then, using two-photon microscopy to image deep within the tissue, the researchers were able to visualize neural axons terminating within adipocytes in an intact fat pad in a living mouse. The sympathetic neurons in fat were sparse—the researchers estimated that less than 8 percent of the adipocytes had direct contact with the nerves.
The researchers then used optogenetics to stimulate the sympathetic neurons within a fat pad in mice. They found that these neurons released norepinephrine upon stimulation, as did leptin treatment. Both manipulations resulted in lipolysis—the breakdown of fat tissue. Conversely, genetically ablating the neural connections to the adipose tissue eliminated the effect of leptin. According toTamas Horvath, a professor of neurobiology at the Yale University School of Medicine who penned an accompanying perspective, this is the first study to apply optogenetic tools to probe the sympathetic nervous system.
While it was known that sympathetic neurons release norepinephrine and that adipocytes have receptors for norepinephrine, the source for the signaling molecule was controversial, as other sources of norepinephrine, such as the adrenal glands, are not required for weight loss, Domingos told The Scientist. “Finding these adipose junctions finally explains how adipose tissue receives its supply of norepineprhine in order to shrink the fat deposits,” said Domingos.
Next, Domingos would like to find pharmacological ways to specifically activate these adipose-associated neurons, mimicking the effect of leptin as a potential treatment for obesity.
For Kenny, the work is another example of the increasing appreciation for the brain-body connection. “This paper is revealing the broader body and brain connection that we are beginning to better appreciate,” he said.
“Lipolysis is another example of a basic process that occurs outside the brain that can be powerfully influenced by what occurs in the brain,” Kenny added. “The brain doesn’t function in isolation but communicates with other organs in beautiful ways.”

W. Zeng et al., “Sympathetic neuro-adipose connections mediate leptin-driven lipolysis,” Cell, doi:10.1016/j.cell.2015.08.055, 2015.


Thursday, September 24, 2015

New articles for vol 3 (2015) and Issue 2 will be published soon

Visit: and submit your article for 2nd Issue of Biohelikon.

Upcoming Articles:

Anti-Idiotype Antibody against Pre-Membrane-Specific Antibody as an Adjunct to Current Dengue Vaccination Strategy
By Andrew W. Taylor-Robinson

Dengue is a rapidly emerging vector-borne viral disease of humans transmitted by mosquitoes of the genus Aedes. Dengue viruses are divided into five antigenically distinct serotypes, DENV-1 to -5. The disease is endemic in over 130 countries, placing almost half of the world’s population at risk. Clinical disease presents as either a mild self-limiting infection or severe complications. Recovery from primary infection by one serotype provides life-long immunity against reinfection by that particular serotype whereas with subsequent infections by other serotypes the risk of developing severe dengue is increased. In contrast to previous understanding that immature dengue virus particles are non-infective it was shown recently that they become highly infectious in the presence of antibodies raised to the pre-membrane protein, prM, of the virion. While no licensed dengue treatment is currently available, several prototype vaccines are being evaluated in clinical studies. Most of these vaccine candidates contain native dengue prM, the presence of which can have the opposite effect to that desired by making immature dengue particles infective. This occurs through a mechanism of prM-specific antibody-dependent enhancement of infection. Hence, in order to safeguard patient welfare when designing future dengue vaccine constructs, provision of another anti-idiotype antibody that binds to and blocks the pathogen-activating region of anti-prM antibody, thus rendering it inactive, should be considered as an adjunct therapy. This strategy would have a potentially significant benefit by reducing cases of secondary infection, which is the major cause of dengue morbidity and mortality.

Effect of pre-operative breast biopsy type on frozen margin status and surgical treatment of breast cancer patients undergoing breast-conserving surgery
By Woo-Gyeong Kim and JungSun Lee

We evaluated the impact of pre-operative biopsy types on interpreting frozen resection margins. We included 301 patients who underwent breast conserving therapy (BCT). During operation, we evaluated the frozen biopsy for resection margin status, and if a positive resection margin was found, re-excision was performed. The following factors were evaluated for correlation with initial frozen margins, re-excision rate, and final operation method: mean age, histologic grade, histology, lymphovascular invasion (LVI), estrogen receptor (ER) status and biopsy type: excisional, vacuum-assisted breast biopsy (VABB) or needle biopsy. A total of 265 patients (88.0%) had negative frozen resection margins, and 36 patients (12%) had positive frozen margins. For patients who underwent needle biopsy, 10.5% (23/219) had positive frozen margins compared with 14.0% (8/57) for excisional biopsy and 20.0% (5/25) for VABB. HG (p=0.002), mean age (p=0.04), histologic type (p<0.001), and number of metastatic lymph node (p<0.001) were significantly correlated with frozen resection margins. In a multivariate analysis, however, only histologic type (p=0.001) was significantly correlated with frozen resection margins. The rate of re-excision was 20% for patients diagnosed with VABB, versus 8.2% with needle biopsy and 8.8% with excisional biopsy (p=0.08). Immediate reconstruction was found more frequently in patients diagnosed by VABB (12.0%) than core needle biopsy (1.8%) and excisional biopsy (3.5%; p=0.02). The use of VABB for pre-operative diagnostic biopsy resulted in a marginal increase of re-excision rate or wider excision in patients undergoing BCT.

and more....