Thursday, June 24, 2010

WHY DOES FEELING LOW HURT?

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When it comes to pain, the two competing schools of thought are that it's either "all in your head" or "all in your body". A new study led by University of Oxford researchers indicates that, instead, pain is an amalgam of the two.

Depression and pain often co-occur, but the underlying mechanistic reasons for this have largely been unknown. To examine the interaction between depression and pain, Dr. Chantal Berna and colleagues used brain imaging to see how healthy volunteers responded to pain while feeling low.

Their findings revealed that inducing depressed mood disrupted a portion of the participants' neurocircuitry that regulates emotion, causing an enhanced perception of pain. In other words, as explained by Dr. Berna, "when the healthy people were made sad by negative thoughts and depressing music, we found that their brains processed pain more emotionally, which lead to them finding the pain more unpleasant."

The authors speculate that being in a sad state of mind and feeling low disables one's ability to regulate the negative emotion associated with feeling pain. Pain, then, has a greater impact. Rather than merely being a consequence of having pain, depressed mood may drive pain and cause it to feel worse.

"Our research suggests depressed mood leads to maladaptive changes in brain function associated with pain, and that depressed mood itself could be a target for treatment by medicines or psychotherapy in this context," commented Dr. Berna. Thus, the next step in this line of research will be to examine this mechanism in individuals who suffer from chronic pain, as these individuals also commonly experience depression. The ultimate goal, of course, is to develop more effective treatments. This is good news for the millions of individuals around the world who suffer from chronic pain and depression.

Elsevier B.V.

BIG BANG THEORY COULD USE SOME TWEAKS

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The Big Bang theory is still the best way to describe the earliest days of the universe, but evidence from nearby galaxies suggests that the theory may be due for some tweaks, according to a Technion-Israel Institute of Technology researcher and colleagues.

Technion cosmologist Prof. Adi Nusser and Princeton University’s P.J.E. Peebles say that old stars in large galaxies, cosmic voids ringed by large galaxies and other tantalizing clues might mean that galaxies and groups of galaxies were built earlier in the course of the expanding universe than predicted by the standard Big Bang theory.

“We do not anticipate that this debate will lead to a substantial departure from the present standard picture of cosmic evolution in the hot Big Bang, because the picture passes a tight network of tests,” they write in the 3 June issue of the journal Nature. “But there is considerable room for adjustment of details, including the galaxies.”

John Kormendy, an astronomer at the University of Texas at Austin and an expert on the evolution of galaxies, praised the researchers for bringing together the latest observational data with theoretical cosmology.

The standard model has been “articulated in enormous detail and works very well,” Kormendy said. “But in various places, including what goes on in individual galaxies, lots of very messy physics come into play, and Peebles and Nusser have highlighted some of those problems.”

“A huge amount of observations have become available and computers have become so powerful that implications of the standard model could be studied in great detail,” said Nusser, of the Technion Physics Department. “The standard model was perceived long ago before these huge data sets became available.”

For instance, the standard model predicts that the largest and most luminous galaxies will form within massive dark matter halos, where gravity has collected matter into highly dense regions. But observations show that there are an unexpected number of large galaxies at the edge of a region called the Local Void, one of the least densely-populated places in our galactic neighborhood, the researchers noted.

It’s a problem that could be resolved if galactic structures grew more rapidly than predicted by the standard theory, “more completely emptying the Local Void and piling up matter on its outskirts,” Nusser and Peebles said.

The standard model also predicts a long and steady rain of cosmic debris—from stars and plasma and even smaller “satellite” galaxies—on to other larger galaxies. But astronomers have shown that the largest and brightest galaxies are not filled with young stars, as would be expected from constant collisions, but are instead populated by some of the oldest stars.

Kormendy’s own work has turned up few signs of major merging in a surprising number of galaxies in our local universe. For many of the biggest galaxies like the Milky Way, he said, “we have no idea right now within our standard picture how galaxies can grow so big without showing products of these mergers.”

“The fossil record in the stars in our home galaxies, the Milky Way, shows our galaxy is a tranquil place that has not been disturbed by in-falling cosmic debris for a long time,” Nusser noted. “The same is true of about half the other large nearby galaxies that can be observed in greatest detail.”

The presence of pure disk galaxies, where stars stream out in a flat plane unanchored by a bulging center, are another indication that the rain of debris ceased before there was time to build up a central bulge of stars, the researchers said.

Adjusting the standard theory to accommodate faster galactic evolution may break a fundamental rule of physics—at least at the level of very large cosmic objects, Nusser said.

For ordinary, visible matter, the acceleration of objects due to gravity depends only on the mass of the objects. That’s why a “feather will fall at the same rate as a ball of iron if let go from the same height,” said Nusser. But he and Peebles propose adding a force between dark matter particles only, as a way to build some speed into the early evolution of galaxies.

“This means that the acceleration of an object will depend on its composition,” Nusser explained. “If a small, so-called satellite galaxy is falling into the Milky Way, then the satellite galaxy will fall at a higher rate if it contains dark matter.”

Nusser said the shift from the current paradigm would not alter what the model predicts about how galaxies are distributed over large distances, such as the distance between galactic clusters. But the adjustments would “allow new physics operating on the scale of galaxies,” he said.

(Photo: ATS)

American Technion Society

COFFEE CONSUMPTION UNRELATED TO ALERTNESS

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The stimulatory effects of caffeine may be nothing more than an illusion according to new research, which shows there is no real benefit to be gained from the habitual morning cup of coffee.

Tests on 379 individuals who abstained from caffeine for 16 hours before being given either caffeine or a placebo and then tested for a range of responses showed little variance in levels of alertness.

The study, published online in the journal of Neuropsychopharmacology, reports that frequent coffee drinkers develop a tolerance to both the anxiety-producing effects and the stimulatory effects of caffeine. While frequent consumers may feel alerted by coffee, evidence suggests that this is actually merely the reversal of the fatiguing effects of acute caffeine withdrawal. And given the increased propensity to anxiety and raised blood pressure induced by caffeine consumption, there is no net benefit to be gained.

Peter Rogers, from the University of Bristol’s Department of Experimental Psychology and one of the lead authors of the study, said: “Our study shows that we don't gain an advantage from consuming caffeine - although we feel alerted by it, this is caffeine just bringing us back to normal. On the other hand, while caffeine can increase anxiety, tolerance means that for most caffeine consumers this effect is negligible.”

Approximately half of the participants were non/low caffeine consumers and the other half were medium/high caffeine consumers. All were asked to rate their personal levels of anxiety, alertness and headache before and after being given either the caffeine or the placebo. They were also asked to carry out a series of computer tasks to test for their levels of memory, attentiveness and vigilance.

The medium/high caffeine consumers who received the placebo reported a decrease in alertness and an increase in headache, neither of which were reported by those who received caffeine. However, their post-caffeine levels of alertness were no higher than the non/low consumers who received a placebo, suggesting caffeine only brings coffee drinkers back up to 'normal'.

The authors also found that the genetic predisposition to anxiety did not deter coffee drinking. In fact, people with the gene variant associated with anxiety tended to consume slightly larger amounts of coffee than those without the variant, suggesting that a mild increase in anxiety may be a part of the pleasant buzz caused by caffeine.

(Photo: Bristol U.)

University of Bristol

EARLY EARTH HAZE LIKELY PROVIDED ULTRAVIOLET SHIELD FOR PLANET

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A new study shows a thick organic haze that enshrouded early Earth several billion years ago may have been similar to the haze now hovering above Saturn's largest moon, Titan, and would have protected primordial life on the planet from the damaging effects of ultraviolet radiation.

The University of Colorado at Boulder scientists believe the haze was made up primarily of methane and nitrogen chemical byproducts created by reactions with light, said CU-Boulder doctoral student Eric Wolf, lead study author. Not only would the haze have shielded early Earth from UV light, it would have allowed gases like ammonia to build up, causing greenhouse warming and perhaps helped to prevent the planet from freezing over.

The researchers determined the haze of hydrocarbon aerosols was probably made up of fluffy, microscopic particles shaped somewhat like cottonwood tree seeds that would have blocked UV but allowed visible light through to Earth's surface, Wolf said.

Prior to the new study, the prevailing scientific view was that the atmosphere of Earth some 3 billion years ago was primarily made up of nitrogen gas with lesser amounts of carbon dioxide, methane, hydrogen and water vapor, said Wolf. "Since climate models show early Earth could not have been warmed by atmospheric carbon dioxide alone because of its low levels, other greenhouse gases must have been involved. We think the most logical explanation is methane, which may have been pumped into the atmosphere by early life that was metabolizing it."

A paper on the subject by Wolf and CU-Boulder Professor Brian Toon of the atmospheric and oceanic sciences department is being published in the June 4 issue of Science. NASA's Planetary Atmosphere Program funded the study.

The output of the sun during the Archean period some 3.8 billion to 2.5 billion years ago is thought to have been 20 percent to 30 percent fainter than today, said Wolf. But previous work by other scientists produced geological and biological evidence that indicates Earth's surface temperatures were as warm or warmer than today.

As part of the early Earth study, Wolf and Toon used a climate model from the National Center for Atmospheric Research and concepts from lab studies by another CU group led by chemistry and biochemistry Professor Margaret Tolbert that help explain the odd haze of Titan, the second largest moon in the solar system and the largest moon of Saturn. Titan came under intense study following the arrival of the Cassini spacecraft at Saturn in 2004, allowing scientists to determine it was the only moon in the solar system with both a dense atmosphere and liquid on its surface.

Previous modeling efforts of early Earth haze by other scientists assumed that aerosol particulates making up the haze were spherical, said Wolf. But the spherical shape does not adequately account for the optical properties of the haze that blanketed the planet.

Lab simulations helped researchers conclude that the Earth haze likely was made up of irregular "chains" of aggregate particles with greater geometrical sizes than spheres, similar to the shape of aerosols believed to populate Titan's thick atmosphere. Wolf said the aggregate aerosol particulates are believed to be fragmented geometric shapes known as fractals that can be split into parts.

During the Archean period there was no ozone layer in Earth's atmosphere to protect life on the planet, said Wolf. "The UV shielding methane haze over early Earth we are suggesting not only would have protected Earth's surface, it would have protected the atmospheric gases below it -- including the powerful greenhouse gas, ammonia -- that would have played a significant role in keeping the early Earth warm."

CU-Boulder researchers estimated there were roughly 100 million tons of haze produced annually in the atmosphere of early Earth during the Archean. "If this was the case, an early Earth atmosphere literally would have been dripping organic material into the oceans, providing manna from heaven for the earliest life to sustain itself," Toon said.

"Methane is the key to make this climate model run, so one of our goals now is to pin down where and how it originated," said Toon. If Earth's earliest organisms didn't produce the methane, it may have been generated by the release of gasses during volcanic eruptions either before or after life first arose -- a hypothesis that will requires further study, he said.

The new CU-Boulder study will likely re-ignite interest in a controversial experiment by scientists Stanley Miller and Harold Urey in the 1950s in which methane, ammonia, nitrogen and water were combined in a test tube. After Miller and Urey ran an electrical current through the mixture to simulate the effects of lightning or powerful UV radiation, the result was the creation of a small pool of amino acids -- the building blocks of life.

Toon said the theory of early Earth being shrouded by a gaseous blanket containing methane and ammonia first arose in the 1960s and was subsequently discarded by scientists. In the 1970s and 1980s some scientists suggested the early Earth atmosphere was similar to those on Mars and Venus with lots of carbon dioxide, another theory that eventually went by the wayside. Since CO2-rich atmospheres do not produce organic molecules easily, scientists began looking in deep-sea volcanic vents and at wayward asteroids to explain early Earth life.

A 1997 paper by the late Carl Sagan of Cornell University and Christopher Chyba, then at the University of Arizona, proposed that an organic aerosol shield in early Earth's atmosphere would have protected the ammonia wafting beneath it, allowing heating to occur at Earth's surface. But the authors proposed the haze particles were spherical rather than irregular aggregate particles Wolf and Toon suggest and did not consider methane to be the driver of the system, eventually sinking that theory.

"We still have a lot of research to do in order to refine our new view of early Earth," said Wolf. "But we think this paper solves a number of problems associated with the haze that existed over early Earth and likely played a role in triggering or at least supporting the earliest life on the planet."

From space, early Earth probably looked much like Titan looks today, said Toon. "It would have been shrouded by a reddish haze that would have been difficult to see through, and the ocean probably was a greenish color caused by dissolved iron in the oceans. It wasn't a blue planet by any means."

(Photo: NASA/JPL/Space Science Institute)

The University of Colorado at Boulder

U OF M RESEARCH HELPS ANSWER AGE-OLD QUESTION OF WHAT MAKES MUSICAL NOTE COMBINATIONS SOUND PLEASING

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Ever since ancient times, scholars have puzzled over the reasons that some musical note combinations sound so sweet while others are just downright dreadful. The Greeks believed that simple ratios in the string lengths of musical instruments were the key, maintaining that the precise mathematical relationships endowed certain chords with a special, even divine, quality. Twentieth-century composers, on the other hand, have leaned toward the notion that musical tastes are really all in what you are used to hearing.

University of Minnesota researchers, reporting in the May 20 online edition of Current Biology, think they may have gotten closer to the truth by studying the preferences of more than 250 college students from Minnesota to a variety of musical and nonmusical sounds. "The question is, what makes certain combinations of musical notes pleasant or unpleasant?" asked Josh McDermott, who conducted the studies at the University of Minnesota before moving to New York University. "There have been a lot of claims. It might be one of the oldest questions in perception.

The University of Minnesota team, including collaborators Andriana Lehr and Andrew Oxenham, was able to independently manipulate both the harmonic frequency relations of the sounds and another quality known as beating. (Harmonic frequencies are all multiples of the same fundamental frequency. For example, notes at frequencies of 200, 300, and 400 hertz are all multiples of 100. Beating occurs when two sounds are close but not identical in frequency. Over time, the frequencies shift in and out of phase with each other, causing the sound to wax and wane in amplitude and producing an audible "wobbling" quality.)

To hear examples of sounds that study participants found both pleasant ("consonant") and unpleasant ("dissonant") visit http://bit.ly/93Oqeb. Also, to hear Oxenham discuss his research in a "University of Minnesota Moment," visit http://bit.ly/dgq4kU.

The researchers' results show that musical chords sound good or bad mostly depending on whether the notes being played produce frequencies that are harmonically related or not. Beating didn't turn out to be as important, says Oxenham. Surprisingly, the preference for harmonic frequencies was stronger in people with experience playing musical instruments. In other words, learning plays a role -- perhaps even a primary one, McDermott argues.

Whether you would get the same result in people from other parts of the world remains to be seen, McDermott says, but the effect of musical experience on the results suggests otherwise. "It suggests that Westerners learn to like the sound of harmonic frequencies because of their importance in Western music. Listeners with different experience might well have different preferences." The diversity of music from other cultures is consistent with this. "Intervals and chords that are dissonant by Western standards are fairly common in some cultures," he says. "Diversity is the rule, not the exception."

That's something that is increasingly easy to lose sight of as Western music has come to dominate radio waves all across the globe. "When all the kids in Indonesia are listening to Eminem," McDermott says, "it becomes hard to get a true sense."

Dr. Oxenham leads the Auditory Perception and Cognition Lab in the U of M's Psychology Department, where the work was completed.

"There are increasing number of people studying the science behind music and the science behind music perception and we are one of growing number of groups doing this kind of work," Oxenham says.

(Photo: U. Minnesota)

University of Minnesota

UIC IN CLINICAL TRIAL TO TREAT BRAIN TUMORS WITH ELECTRIC FIELDS

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The University of Illinois at Chicago is taking part in an international, multi-center study for patients newly diagnosed with the most common and aggressive type of brain tumor, glioblastoma multiforme, or GBM.

The clinical trial will evaluate the safety and efficacy of an investigational device that targets rapidly growing cancer cells with intermediate frequency electrical fields. Treatment with the device will be tested in combination with standard-of-care therapy and compared to standard-of-care therapy alone.

The Novo-TTF is a non-invasive medical device that disrupts the division of cancer cells in the brain using alternating electrical fields called "tumor-treating fields" delivered to the surface of the scalp by insulated electrodes.

Standard treatment includes surgical removal of the tumor, radiation and chemotherapy with an oral drug called temozolomide.

Dr. Herbert Engelhard, associate professor of neurosurgery and site investigator for the trial at UIC, said that in a pilot study, "early data suggest that this investigational treatment may increase the length of time before disease progression and increase median overall survival in newly diagnosed GBM patients."

"The concept is quite simple," he said. "The tumor-treating fields cause the quickly growing cancer cells to die instead of dividing. And because brain tumor cells have different electrical properties than healthy cells, the healthy cells are spared from damage."

After a baseline MRI is used to determine the location of the tumor, physicians place several electrodes on the patient's shaved head. The electrodes are connected to the Novo-TTF medical device powered by a portable battery. The patient remains on the portable device for 22 hours a day, indefinitely, while continuing his or her daily activities.

Approximately five out of every 100,000 Americans are diagnosed each year with glioblastoma, according to the American Brain Tumor Association. Glioblastoma multiforme is the most deadly of all brain tumors. Standard therapy often does not provide a cure and causes side effects that diminish quality of life.

"Unfortunately, many patients with these aggressive brain tumors do not have many options," said Engelhard. "The goal is to provide new treatment options, improve survival and hopefully improve their quality of life."

While not considered a cure for the deadly brain tumor, the treatment may extend life for some people, said Engelhard. However, as the research is in its early stages, the benefit of Novo-TTF for patients with GBM has not yet been established.

The trial will enroll approximately 283 patients at 12 U.S. centers and nine centers in Europe. Two-thirds of the patients will receive continuous therapy with the NovoTTF-100A in addition to standard treatment; the other one-third will receive the standard treatment alone. All patients will be evaluated for disease progression.

UIC currently has three patients enrolled.

One patient, Gerald Bagnowski of Chicago, said that he continues his active lifestyle, which includes being a part-time elementary school gym teacher and an avid golfer, despite his diagnosis and treatment with the NovoTTF.

"To me, it was a life-or-death situation, and I felt the study was in my best interest," said Bagnowski, who is married and has three adult sons.

In 2006, in an earlier clinical trial for patients who had recurrent glioblastoma, UIC enrolled the first person in the U.S. who was randomly assigned to receive the novel NovoTTF therapy.

Today, 54-year-old Daniel Torres of Chicago has worn the device for 3 1/2 years.

Results of the previous clinical trial for patients with recurrent GBM have not yet been published.

The University of Illinois at Chicago

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