For DARPA, the secretive military research agency, it’s not enough for a prosthetic limb to simply resemble a normal one, or for a patient to be able to move it through some remote control. DARPA-backed engineers are attempting to build a system in which peripheral nerves would be reattached to artificial limbs, which could send signals to a brain sensor that could reply. This would be a vast improvement over prosthetics that require conscious directives, and could turn a prosthetic into something that responds the way an ordinary limb would.
Darpa’s after a prosthetic that can record motor-sensory signals right from peripheral nerves (those that are severed when a limb is lost) and then transmit responding feedback signals from the brain. That means an incredibly sensitive platform, “capable of detecting sufficiently strong motor-control signals and distinguishing them from sensory signals and other confounding signals,” in a region packed tightly with nerves. Once signals are detected, they’ll be decoded by algorithms and transmitted to the brain, where a user’s intended movements would be recoded and transmitted back to the prosthetic. [Wired.com]
According to the team behind the system at Johns Hopkins University’s Applied Physics Laboratory, tests on monkeys have shown that the primates have remarkable success controlling a prosthesis through a cortical chip implanted in their brains, and researchers have undertaken some human tests. What remains to be seen, though, is how much dexterity people can get through this process.
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When people suffer a concussion, is the evidence of that head trauma just hanging out in their bloodstream, waiting to be found? A U.S. Army project made news late last week by claiming to have found a biomarker for traumatic brain injury, which could allow for a simple diagnosis via blood test.
Make no mistake—a biomarker would be a tremendous medical advance in catching an elusive and hard-to-quantify condition. But don’t get too excited just yet: This was a preliminary study, and some other neuroscientists are not convinced the test will work on in a real, clinical trail.
Army Col. Dallas Hack, who has oversight of the research, says recent data show the blood test, which looks for unique proteins that spill into the blood stream from damaged brain cells, accurately diagnosing mild traumatic brain injury in 34 patients. Doctors can miss these injuries because the damage does not show up on imaging scans, and symptoms such as headaches or dizziness are ignored or downplayed by the victims. [USA Today]
Hack certainly wasn’t going to downplay the achievement by his team, which partners with the Florida-based company Banyan Biomarkers on this project.
Army Col. Dallas Hack says the new technique could rival the discovery of unique proteins in the 1970s that help doctors identify heart disease. “This will in fact do for brain injury what that test did for chest pain,” Hack said. “It’s going to change medicine entirely.” [UPI]
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Yes, it’s a milestone. The first federally approved trial of an embryonic stem cell therapy has begun, and the first patient with a spinal cord injury has been injected with a treatment made from embryonic stem cells. But if all goes well with the trial, conducted by the biotech company Geron, there won’t be any dramatic results–the trial is simply intended to test the treatment’s safety, and patients will receive very low doses of the stem cell concoction.
The patient, whose name was not disclosed, is enrolled at the Shepherd Center, a rehabilitation center in Atlanta; the company has said it plans to enroll 8 to 10 patients in the study at sites around the country. Even if all goes well in the early-stage study, the treatment faces many years of testing for effectiveness before it could be approved as a therapy for spinal injuries. [New York Times]
For the trial, which gained final approval in August, Geron is working with a technique pioneered by the neurobiologist Hans Keirstead, who licensed the technology to Geron.
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Researchers have designed the first artificial kidney small enough to slip comfortably inside the human body, and they say the technological breakthrough could be an enormous benefit for people grappling with kidney disease. Modern medicine can keep patients alive if their kidneys fail via external dialysis machines that filter toxins from their blood, but it’s a grueling and imperfect process.
Patients must be tethered to machines at least three times a week for three to five hours at a stretch. Even then, a dialysis machine is only about 13 percent as effective as a functional kidney, and the five-year survival rate of patients on dialysis is just 33 to 35 percent. To restore health, patients need a kidney transplant, and there just aren’t enough donor organs to go around. In August, there were 85,000 patients on the U.S. waiting list for a kidney … while only 17,000 kidney transplants took place last year. [Technology Review]
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Six patients’ eyes have connected with “biosynthetic” replacement corneas, growing nerves and cells into the fakes as if they were real human tissue. With more trials and improvements in implant technique, researchers say the biosynthetic corneas might replace the expensive, rejection-prone, and scarce cadaver corneas that are currently used in transplants. This is good news for people who have lost vision due to inflamed or scarred corneas, and who are hoping to bring the world back into focus.
The findings appeared yesterday in Science Translational Medicine. The corneas allowed six out of a total of ten trial patients with advanced keratoconus, a condition which causes corneal scarring, to see just as well as if they had a traditional cadaver cornea replacement. Natural corneas, which refract light coming into the eye and help it to focus, consist of parallel strands of collagen; the biosynthetic corneas used collagen made in a lab by the biotech company Fibrogen.
“This study … is the first to show that an artificially fabricated cornea can integrate with the human eye and stimulate regeneration,” said May Griffith of the Ottawa Hospital Research Institute, who led the study. “With further research, this approach could help restore sight to millions of people who are waiting for a donated human cornea for transplantation.” [Reuters]
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Researchers have found the secret to improving a robot’s sense of smell: Shove frog eggs up its nose. A team at the University of Tokyo has developed a sensor made from a genetically modified frog egg that can help a robot pick out insect smells and pheromones.
As useful as a moth-smelling robot may seem, researchers believe the study published yesterday in Proceedings of the National Academy of Sciences is just one step towards an inexpensive but sensitive chemical detector. Study coauthor Shoji Takeuchi explains that such a device could pick out gases like carbon dioxide:
“When you think about the mosquito, it is able to find people because of carbon dioxide from the human. So the mosquito has CO2 receptors. When we can (extract) DNA (from the mosquito) we can put this DNA into the frog eggs to detect CO2.” [Reuters]
Here’s how they did it.
Step 1 — Get Some Frog Eggs
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In early 2010, some scientists offered their predictions for the new decade which this blog covered in the post, “Scientists Predict: The 2010s Will Be Freakin’ Awesome–With Lasers.” In what could be an early sign of that sunny prognostication coming true, researchers have announced that they’ve controlled the beating of an embryonic heart with an infrared laser beam. While the work is in its early stages, researchers say this remarkable advance will help them study heart disease and could one day lead to optical pacemakers.
The embryonic hearts in question came from quail eggs. Each quail embryo was only two or three days old so the heart measured just 2 cubic millimeters in volume; at that stage, the heart is essentially a clump of cells that hasn’t yet developed its four-chambered structure. The pulses of infrared light were delivered by an optical fiber that ended 500 micrometres from the embryo.
Before they switched on the laser, the heart beat once every 1.5 seconds, but firing the laser twice a second quickened the heartbeat to match the laser rate as long as the laser fired…. ”It worked beautifully: the heart rate was in lockstep with the laser pulse rate,” says [study coauthor] Duco Jansen of Vanderbilt University in Nashville, Tennessee. [New Scientist]
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Meet the cyborg cell. By attaching probes with nano-hairpin connectors to living cells, researchers have measured electrical currents from inside. They hope the probes will provide a useful way to monitor cells’ health.
A team at Harvard University conducted the study, which appears in Science. Though other probes can measure the currents in electrical impulse-producing cells–such as beating heart cells–none have given researchers the precision of measuring from inside. The probes designed in this study allowed researchers to successfully measure the electric pulses from cultured chicken heart cells’ beating.
One of the team’s challenges was getting the wires to kink into the hairpin shape–a difficult maneuver using traditional nanowire-making techniques. They noted if they stopped the wire as it formed, they could force it to bend.
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One might think that identical-twin bacteria—clones of each other—would grow up and live very similarly. But a study published today in Science that examined individual bacterial cells in detail found that genetically identical E. Coli cells actually seem to express their genes quite differently, simply because of the random accidents of how their molecular machinery happens to operate.
“The paper is quite rich,” said Sanjay Tyagi, a molecular biologist at New Jersey Medical School who was not involved in the research [but published a perspectives piece on it]. “People think that if an organism has a particular genotype, it determines its phenotype [observable characteristics]–that there’s a one-to-one relationship,” said Tyagi. “But as it turns out, [differences in gene expression] can arise just from chance.” [The Scientist]
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Dick Cheney may not have a pulse, but part of his ticker is spinning at 9,000 RPM.
The former Vice President provided an instant laugh line for comedians this week when it was revealed that during his latest heart surgery, doctors installed a new implant called left ventricular assist device, or LVAD.
The pump runs something like a drill bit, continuously rotating at 9,000 rotations per minute rather than squeezing and releasing, so Cheney now officially has no pulse, according to Dr. Stuart D. Russell, chief of heart failure and transplantation at Johns Hopkins’ Comprehensive Transplant Center [Baltimore Sun].
A device like Cheney’s is implanted in his chest, with the exception of the batteries, which the user must wear in a separate vest. (Though the Baltimore Sun reports that patients can wear the power source “holster style,” which may be more Cheney’s style.)
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Replacing a traditional needle with a fingernail-sized patch may one day make some immunizations painless and possibly more effective. A study published in Nature earlier this week shows that a patch–a square of “microneedles” that are too short to register a typical shot’s sting and that dissolve in the skin–effectively immunized mice against a strain of the flu virus.
The researchers have yet to test the patch on humans, and that next step could take a few years; the move from a successful animal trial to a human trial isn’t a small feat. Still, many see this patch’s promise. As Paul Offit, director of the Vaccine Education Center and chief of infectious diseases at Children’s Hospital of Philadelphia, says:
“The caveat is, this needs to be extended to humans…. It’s not uncommon for vaccines or vaccine delivery systems to look very promising in experimental animals, then fail in humans. But there is every reason to believe this kind of technology could be applicable to children and adults.” [HealthDay News]
If the patch proves successful in human studies, here are some reasons it might quickly catch on.
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Investigators are now swabbing dog cheeks. A dog DNA database–similar to the one the FBI keeps for criminals–may help to deter dog-fighting.
Dog-fighting is a federal crime and a felony offense in every U.S. state, but it’s difficult to detect and stop. Officers rarely catch fighters in the act, and the industry, as a multimillion-dollar business, makes money not only from gambling on the violent and often fatal matches, but also from breeding and selling champion dogs.
The New York Times reports that some dogs sell for as high as $50,000 dollars. The American Society for the Prevention of Cruelty to Animals estimates that there could be tens of thousands of people involved in dog fighting in the United States.
So where does the genetics come in?
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Step 1: Take a rat lung. Step 2: Strip away all of its living cells, leaving only a fibrous “scaffold” of connective tissue. Step 3: Bathe the scaffold in lung cells taken from newborn rats, and put the whole thing in a bioreactor to let the cells multiply and spread. Step 4: A few days later, when the reconstructed lung is again filled with blood vessels and alveoli, transplant the organ into a living rat. Step 5: Watch in awe as the lung begins to function.
That’s the short version of the experiment Yale University researchers just published in Science. The study was a result of a change in direction for lead researcher Laura Niklason:
Niklason spent several years trying to create a synthetic lung scaffold, but in the end concluded it was too difficult. “I decided I couldn’t do it, and probably nobody else could either,” she said. [National Geographic]
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In another step forward in the quest to create artificial life in a test tube, a team of genetic engineers led by Craig Venter has built a synthetic genome and proved that it can power up when placed inside an existing cell.
Dr. Venter calls the result a “synthetic cell” and is presenting the research as a landmark achievement that will open the way to creating useful microbes from scratch to make products like vaccines and biofuels. At a press conference Thursday, Dr. Venter described the converted cell as “the first self-replicating species we’ve had on the planet whose parent is a computer.” [The New York Times]
The technical achievement is worth crowing about. The researchers built on Venter’s trick from last year, in which he took the genome from one bacterium, transferred it the hollowed-out shell of a different bacterial species, and watched as the new cell “booted up” successfully. In this new step, the researchers built a genome from scratch, copying the genetic code from a bacterium that infects goats and introducing just a few changes as a “watermark”; then they transferred that synthetic genome to a cell. As the researchers report in Science, the cell functioned and replicated, creating more copies of the slightly altered goat-infecting bacterium–now nicknamed Synthia.
But the reactions to Venter’s accomplishment have been mixed–while some celebratory headlines trumpeted the creation of artificial life, many scientists said the reaction was overblown, and took issue with Venter’s claim of having created a truly synthetic cell. Here, we round up a selection of responses from all corners of the science world.
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The implants of the future will be powered by the energy sources already inside your body. Last week we saw scientists take a step toward this vision by developing a transistor that used the fuel from our cells (a molecule called ATP). And now, a French team has announced the development of a fuel cell that can use the glucose (sugar) inside an animal to produce electricity. Their paper is available free at the journal PLoS One.
The team surgically implanted the device in the abdominal cavity of two rats. The maximum power of the device was 6.5 microwatts, which approaches the 10 microwatts required by pacemakers [Technology Review].
Philippe Cinquin and his team created the cell, in which graphite electrodes are coated with enzymes that oxidize glucose to produce energy. Then connectors carry the electricity from the cell to whatever it’s powering.
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