Archive for the ‘University of Michigan’ Category

Recently the mainstream has come to embrace the fact that the job market for Ph.D. biomedical researchers is overcrowded. According to a new report from a working group of the National Institutes of Health (NIH) Advisory Committee to the Director (ACD), the job market looks very different for physician-scientists. In fact, “[t]here may not be enough [physician-scientists] to replace those preparing to retire,” Jocelyn Kaiser reports in a ScienceInsider.

The working group analyzed data on “M.D.-Ph.D.s, M.D.s, nurses, and other researchers with clinical training” collected from an American Medical Association (AMA) survey, finding—in stark contrast to trends in the number of biomedical Ph.D. graduates—that “[t]he number of physicians conducting research has declined 5.5% since 2003 to about 13,700 in 2012.” The working group also analyzed data from NIH and AMA and found that many NIH-funded principal investigators (PIs) are in their 60s and 70s, and that the number of PIs under 60 is declining.

The data have fueled concern for the future of the physician-scientist population. The need for younger physician-scientists is getting more attention because “we’re worried that they’re [physician-scientists are] going to dry up and this is going to be a serious problem,” said working group co-chair David Ginsburg of the University of Michigan, Ann Arbor, in a call with reporters, as quoted by Kaiser.

Kaiser notes that some of the working group’s recommendations for fixing these problems echo those of the 2012 Biomedical Workforce Working Group of the ACD, led by Princeton University molecular biologist Shirley Tilghman: Enrich training programs, and give more weight to proposals from young researchers. “It also recommends creating a category for physician-scientists within the so-called kangaroo, or K99/R00, awards—two-stage awards that include a training grant and research support,” Kaiser writes.

Thanks to Dr. Lutter for bringing this to the attention of the It’s Interesting community.

http://sciencecareers.sciencemag.org/career_magazine/previous_issues/articles/2014_06_10/caredit.a1400145

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To negotiate floods and cross streams, fire ants band together — literally — linking together to form rafts and bridges in a feat of social cooperation and biophysics. Now, engineers have made a close study of the ants’ architectural technique, pointing the way towards new approaches for robot designers and materials scientists.

To understand the properties of the ant structures, David Hu, a mechanical engineer at the Georgia Institute of Technology in Atlanta, sought to observe not just the surface of the ant clumps but the structure and joints underneath.

First, Hu and his team collected ant colonies — shovelling them, dirt and all, into buckets. After separating out the ants from the dirt, they then put 100 or so ants into a cup and swirled, causing the ants to form into a ball (no water necessary — they come together almost like dough). The researchers then froze the ball with liquid nitrogen so they could examine it in a micro-computed-tomography scanner to come up with a 3-D picture.

But the heat of the scanner melted the ball into a heap of dead ants. After months of experimenting with techniques to keep it together, lead author Paul Foster, now at the University of Michigan, found an unlikely source of inspiration in crack cocaine — specifically, in a method of vaporizing the drug to inhale it. “We did the same process — not with crack, but glue,” says Hu, adding that the authors decided against calling it the ‘crack-pipe method’ in their paper. The researchers heated the glue in an aluminium pot over a flame, with the frozen ant ball suspended on mesh above. The glue vapour rose and lightly coated the ants.

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Hu and his team found that the ants had grabbed hold of one another with adhesive pads on their legs, which they stretched out to create pockets of air. They also tended to orient themselves perpendicularly to one another, distributing their weight and creating a light, buoyant structure. The formation seems to take advantage of the ants’ different sizes, with smaller ants slotting neatly in between larger ones to add more connections. Each ant averaged 14 connections to fellow ants. The study is published today in the Journal of Experimental Biology.

Radhika Nagpal, who creates biologically inspired robots at Harvard University in Cambridge, Massachusetts, says that Hu’s ants could make great models for modular robots. “There’s lots of interesting outcomes of this work,” she says. “Imagine robots that need to construct a barrier or patch a hole during a disaster response.”

Rather than building one perfect robot, she notes, designers are increasingly exploring building a “colony of simple robots that use their bodies and the connections between them to build new structures.” Most projects in this vein have used geometric robots with precise connections. But ants do not create a perfect lattice, suggesting a sloppier, more organic approach in which robot shapes are varied and irregular and connections between them are inexact, Nagpal says. Hu thinks that the properties of ant structures might not only inform the design of robot swarms, but also the design of ‘smart’ materials that assemble themselves in response to temperature, light or other variables.

Hu is working on getting larger ant structures — recognizably distinct as bridges, rafts and other forms — into a bigger scanner to begin detailing the properties of the different functional shapes. And once they are frozen and coated in glue, they will last forever, Hu says. “One day,” he jokes, “we will have a miniature museum of ant structures.”

Thanks to Da Brayn for bringing this to the attention of the It’s Interesting community.

http://www.scientificamerican.com/article/secrets-of-ant-rafts-revealed/

by Joe Palca

There are smartphone apps for monitoring your diet, your drugs, even your heart. And now a Michigan psychiatrist is developing an app he hopes doctors will someday use to predict when a manic episode is imminent in patients with bipolar disorder.

People with the disorder alternate between crushing depression and wild manic episodes that come with the dangerous mix of uncontrollable energy and impaired judgment.

There are drugs that can prevent these episodes and allow people with bipolar disorder to live normal lives, according to Dr. Melvin McInnis, a psychiatrist at the University of Michigan Medical Center. But relapses are common.

“We want to be able to detect that well in advance,” McInnis says. “The importance of detecting that well in advance is that they reach a point where their insight is compromised, so they don’t feel themselves that anything is wrong.”

Early detection would give doctors a chance to adjust a patient’s medications and stave off full-blown manic episodes.

McInnis says researchers have known for some time that when people are experiencing a manic or depressive episode, their speech patterns change. Depressed patients tend to speak slowly, with long pauses, whereas people with a full-blown manic attack tend to speak extremely rapidly, jumping from topic to topic.

“It occurred to me a number of years ago that monitoring speech patterns would be a really powerful way to devise some kind of an approach to have the ability to predict when an episode is imminent,” says McInnis.

So he and some computer science colleagues invented a smartphone app. The idea is that doctors would give patients the app. The app would record whenever they spoke on the phone. Once a day, the phone would send the recorded speech to a computer in the doctor’s office that would analyze it for such qualities as speed, energy and inflection.

Right now the app is being tested with 12 or 15 volunteers who are participating in a longitudinal study of bipolar disorder.

McInnis and his colleagues presented preliminary results at this year’s International Conference on Acoustics, Speech and Signal Processing, and so far, things are looking encouraging. McInnis says the software is reasonably good at detecting signs of an impending manic attack. It’s not quite as good catching an oncoming depression.

For now, this app is only intended for patients with bipolar disorder, but McInnis thinks that routinely listening for changes in speech could be an important tool for early detection of a variety of diseases.

Tastes are a privilege. The oral sensations not only satisfy foodies, but also on a primal level, protect animals from toxic substances. Yet cetaceans—whales and dolphins—may lack this crucial ability, according to a new study. Mutations in a cetacean ancestor obliterated their basic machinery for four of the five primary tastes, making them the first group of mammals to have lost the majority of this sensory system.

The five primary tastes are sweet, bitter, umami (savory), sour, and salty. These flavors are recognized by taste receptors—proteins that coat neurons embedded in the tongue. For the most part, taste receptor genes present across all vertebrates.

Except, it seems, cetaceans. Researchers uncovered a massive loss of taste receptors in these animals by screening the genomes of 15 species. The investigation spanned the two major lineages of cetaceans: Krill-loving baleen whales—such as bowheads and minkes—were surveyed along with those with teeth, like bottlenose dolphins and sperm whales.

The taste genes weren’t gone per se, but were irreparably damaged by mutations, the team reports online this month in Genome Biology and Evolution. Genes encode proteins, which in turn execute certain functions in cells. Certain errors in the code can derail protein production—at which point the gene becomes a “pseudogene” or a lingering shell of a trait forgotten. Identical pseudogene corpses were discovered across the different cetacean species for sweet, bitter, umami, and sour taste receptors. Salty tastes were the only exception.

“The loss of bitter taste is a complete surprise, because natural toxins typically taste bitter,” says zoologist Huabin Zhao of Wuhan University in China who led the study. All whales likely descend from raccoon-esque raoellids, a group of herbivorous land mammals that transitioned to the sea where they became fish eaters. Plants range in flavors—from sugary apples to tart, poisonous rhubarb leaves—and to survive, primitive animals learned the taste cues that signal whether food is delicious or dangerous. Based on the findings, taste dissipated after this common ancestor became fully aquatic—53 million years ago—but before the group split 36 million years ago into toothed and baleen whales.

“Pseudogenes arise when a trait is no longer needed,” says evolutionary biologist Jianzhi Zhang of the University of Michigan, Ann Arbor, who was not involved in the study. “So it still raises the question as to why whales could afford to lose four of the five primary tastes.” The retention of salty taste receptors suggests that they have other vital roles, such as maintaining sodium levels and blood pressure.

But dulled taste perception might be dangerous if noxious substances spill into the water. Orcas have unwittingly migrated into oil spills, while algal toxins created by fertilizer runoff consistently seep into the fish prey of dolphins living off the Florida coast.

“When you have a sense of taste, it dictates whether you swallow or not,” says Danielle Reed, a geneticist at the Monell Chemical Senses Center in Philadelphia, Pennsylvania. She was not involved with the current work, but co-authored a 2012 paper that found the first genetic inklings that umami and sweet taste receptors were missing in cetaceans, albeit in only one species—bottlenose dolphins.

Flavors are typically released by chewing, but cetaceans tend to swallow their food whole. “The message seems clear. If you don’t chew your food and prefer swallowing food whole, then taste really becomes irrelevant,” Reed says.

http://news.sciencemag.org/biology/2014/05/whales-cant-taste-anything-salt

Thanks to Dr. Rajadhyaksha for bringing this to the attention of the It’s Interesting community.

At a hospital in Pittsburgh, surgeons are now allowed to place patients into a state of suspended animation. If a patient arrives with a traumatic injury, and attempts to restart their heart have failed — if they’re on the doorstep of death — they will have their blood replaced with a cold saline solution, which stops almost all cellular activity. At this point, the patient is clinically dead — but if the doctors can fix the injury within a few hours, they can be returned to life from suspended animation by replacing the saline with blood.

Or at least, that’s the theory. The technique of suspended animation (or “emergency preservation and resuscitation” as non-sci-fi doctors prefer to call it) was first trialed on pigs in 2002. Hasan Alam, working with his colleagues at the University of Michigan Hospital, drugged up a pig, created a massive hemorrhage to simulate the effect of a massive gunshot wound, and then replaced its blood with a cold saline solution, cooling the pig’s cells to just 10 Celsius (50F). After the injury was treated, the pig was gradually warmed back up by replacing the saline with blood. Usually the pig’s heart started beating on its own, and despite the pig being dead for a few hours, there was no physical or cognitive impairment. Now, it’s time to try it out on humans. [Research paper: dx.doi.org/10.1067/msy.2002.125787 – “Learning and memory is preserved after induced asanguineous hyperkalemic hypothermic arrest in a swine model of traumatic exsanguination”]

Roughly once a month, UPMC Presbyterian Hospital in Pittsburgh receives a patient who has suffered a cardiac arrest after some kind of traumatic injury (gunshot, stabbing, etc.), and hasn’t responded to normal methods of restarting their heart. Because there’s currently no other kind of treatment, and because these kinds of wounds are nearly always fatal, the surgeons don’t need consent to carry out the suspended animation. The technique will be used on 10 patients, with the outcome compared against 10 people who didn’t. Samuel Tisherman, the surgeon who is leading the trial, told New Scientist that they’ll then refine their technique and try it out on 10 more patients — at which point, there should be enough data to work out whether suspended animation is worth rolling out to other hospitals.

The process is much the same for humans as it was for pigs. The first step is to replace all of the blood in the heart and brain — the two areas most sensitive to hypoxia — with with cold saline. Then, the saline is pumped around the rest of the body. After 15 minutes, the patient’s temperature reaches 10C — they have no blood, no brain activity, and they’re not breathing. Technically they’re dead — but because the metabolism of your cells slow down at low temperatures, they can survive for a few hours using anaerobic respiration (usually it’s just a few minutes). ”We’ve always assumed that you can’t bring back the dead. But it’s a matter of when you pickle the cells,” said Peter Rhee, who helped developed the suspended animation technique.

For now, this process is only being used for cardiac arrests following traumatic injuries, but in the future Tisherman says he hopes to use the technique for other conditions as well. The other big question, of course, is whether this technique can be used to suspend animation for more than just a couple of hours. If I have my blood replaced with saline, and then use cryonics to cool my body down yet further, could I be “dead” for a few months or weeks or years before being warmed up again? If sci-fi has taught us anything, it’s that suspended animation (or stasis as it’s sometimes called) is one of the most potentially exciting technologies — not only for rich people trying to extend their lives, but for the possibly centuries-long journeys that our first interstellar explorers will embark upon.

http://www.extremetech.com/extreme/179296-humans-will-be-kept-between-life-and-death-in-the-first-suspended-animation-trials

fly-getty

Sexually frustrated fruit flies die earlier, new research suggests.

Scientists made the discovery by genetically modifying male flies to release female sex pheromones. Other males were left nearby and therefore instantly aroused by the pheromones. Some were allowed to mate, but others weren’t.

The findings, published in the journal Science, show that the sexually frustrated flies’ lives were 40 per cent shorter, while those who did mate suffered less stress.

Dr Scott Pletcher, Assistant Professor of Molecular & Integrative Physiology at the University of Michigan, co-authored the research. He told the BBC: “We immediately observed that (the non-mating flies) looked quite sick very soon in the presence of these effeminised males.”

A brain chemical, neuropeptide F (NPF), appeared to play a big role. NPF levels went up once flies were aroused. It would normally go down again upon mating.

But when it stayed high, it caused the stress and apparently the premature deaths.

Dr Pletcher went on: “Evolutionarily we hypothesise the animals are making a bet to determine that mating will happen soon.

“Those that correctly predict may be in a better position, they either produce more sperm or devote more energy to reproduction in expectation, and this may have some consequences [if they do not mate].”

http://www.independent.co.uk/news/science/sexual-frustration-will-give-you-a-shorter-and-more-stressful-life-if-you-are-a-fruit-fly-8972673.html

Thanks to Dr. D for bringing this to the attention of the It’s Interesting community.

sn-brain

What people experience as death creeps in—after the heart stops and the brain becomes starved of oxygen—seems to lie beyond the reach of science. But the authors of a new study on dying rats make a bold claim: After cardiac arrest, the rodents’ brains enter a state similar to heightened consciousness in humans. The researchers suggest that if the same is true for people, such brain activity could be the source of the visions and other sensations that make up so-called near-death experiences.

Estimated to occur in about 20% of patients who survive cardiac arrest, near-death experiences are frequently described as hypervivid or “realer-than-real,” and often include leaving the body and observing oneself from outside, or seeing a bright light. The similarities between these reports are hard to ignore, but the conversation about near-death experiences often bleeds into metaphysics: Are these visions produced solely by the brain, or are they a glimpse at an afterlife outside the body?

Neurologist Jimo Borjigin of the University of Michigan, Ann Arbor, got interested in near-death experiences during a different project—measuring the hormone levels in the brains of rodents after a stroke. Some of the animals in her lab died unexpectedly, and her measurements captured a surge in neurochemicals at the moment of their death. Previous research in rodents and humans has shown that electrical activity surges in the brain right after the heart stops, then goes flat after a few seconds. Without any evidence that this final blip contains meaningful brain activity, Borjigin says “it’s perhaps natural for people to assume that [near-death] experiences came from elsewhere, from more supernatural sources.” But after seeing those neurochemical surges in her animals, she wondered about those last few seconds, hypothesizing that even experiences seeming to stretch for days in a person’s memory could originate from a brief “knee-jerk reaction” of the dying brain.

To observe brains on the brink of death, Borjigin and her colleagues implanted electrodes into the brains of nine rats to measure electrical activity at six different locations. The team anesthetized the rats for about an hour, for ethical reasons, and then injected potassium chloride into each unconscious animal’s heart to cause cardiac arrest. In the approximately 30 seconds between a rat’s last heartbeat and the point when its brain stopped producing signals, the team carefully recorded its neuronal oscillations, or the frequency with which brain cells were firing their electrical signals.

The data produced by electroencephalograms (EEGs) of the nine rats revealed a highly organized brain response in the seconds after cardiac arrest, Borjigin and colleagues report online today in the Proceedings of the National Academy of Sciences. While overall electrical activity in the brain sharply declined after the last heartbeat, oscillations in the low gamma frequency (between 25 and 55 Hz) increased in power. Previous human research has linked gamma waves to waking consciousness, meditative states, and REM sleep. These oscillations in the dying rats were synchronized across different parts of the brain, even more so than in the rat’s normal waking state. The team also noticed that firing patterns in the front of the brain would be echoed in the back and sides. This so-called top-down signaling, which is associated with conscious perception and information processing, increased eightfold compared with the waking state, the team reports. When you put these features together, Borjigin says, they suggest that the dying brain is hyperactive in its final seconds, producing meaningful, conscious activity.

The team proposed that such research offers a “scientific framework” for approaching the highly lucid experiences that some people report after their brushes with death. But relating signs of consciousness in rat brains to human near-death experiences is controversial. “It opens more questions than it answers,” says Christof Koch, a neuroscientist at the Allen Institute for Brain Science in Seattle, Washington, of the research. Evidence of a highly organized and connected brain state during the animal’s death throes is surprising and fascinating, he says. But Koch, who worked with Francis Crick in the early 1980s to hypothesize that gamma waves are a hallmark of consciousness, says the increase in their frequency doesn’t necessarily mean that the rats were in a hyperconscious state. Not only is it impossible to project any mental experience onto these animals, but their response was also “still overlaid by the anesthesiology,” he says; this sedation likely influenced their brain response in unpredictable ways.

Others share Koch’s concerns. “There is no animal model of a near-death experience,” says critical care physician Sam Parnia of Stony Brook University School of Medicine in New York. We can never confirm what animals think or feel in their final moments, making it all but impossible to use them to study our own near-death experiences, he believes. Nonetheless, Parnia sees value in this new study from a clinical perspective, as a step toward understanding how the brain behaves right before death. He says that doctors might use a similar approach to learn how to improve blood flow or prolong electrical activity in the brain, preventing damage while resuscitating a patient.

Borjigin argues that the rat data are compelling enough to drive further study of near-death experiences in humans. She suggests monitoring EEG activity in people undergoing brain surgery that involves cooling the brain and reducing its blood supply. This procedure has prompted near-death experiences in the past, she says, and could offer a systematic way to explore the phenomenon.

read more here: http://news.sciencemag.org/brain-behavior/2013/08/probing-brain%E2%80%99s-final-moments

Thanks to Kebmodee for bringing this to the attention of the It’s Interesting community.