Doubling the daily allowance of protein intake with diet and exercise protects muscle loss

Aug. 29, 2013 — A new report appearing in the September issue of The FASEB Journal challenges the long-held adage that significant muscle loss is unavoidable when losing weight through exercise and diet. In the report, scientists show that consuming twice the recommended daily allowance (RDA) of protein while adhering to a diet and exercise plan prevents the loss of muscle mass and promotes fat loss. Tripling the RDA of protein, however, failed to provide additional benefits.Share This:”It is our hope that the findings from this well-controlled study will be discussed and cited by the Institute of Medicine for the updated Dietary Reference Intakes on protein,” said Stefan M. Pasiakos, Ph.D., a researcher involved in the work from the Military Nutrition Division at the U.S. Army Research Institute of Environmental Medicine in Natick, MA. “We believe that the RDA for protein should be based on a level to optimize health, as well as prevent deficiencies, and our data demonstrate a potential inadequacy of the current RDA for sparing muscle mass during weight loss, which may affect a significant portion of the population.”To make this discovery, Pasiakos and colleagues assigned young men and women controlled diets for 31 days that provided dietary protein at three different levels: 1) the U.S. RDA, 2) twice the U.S. RDA, and 3) three times the U.S. RDA. …

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Biomarkers for possible blood test to predict suicide risk identified

Aug. 20, 2013 — Indiana University School of Medicine researchers have found a series of RNA biomarkers in blood that may help identify who is at risk for committing suicide.In a study reported Aug. 20 in the advance online edition of the Nature Publishing Group journal Molecular Psychiatry, the researchers said the biomarkers were found at significantly higher levels in the blood of both bipolar disorder patients with thoughts of suicide as well in a group of people who had committed suicide.Principal investigator Alexander B. Niculescu III, M.D., Ph.D., associate professor of psychiatry and medical neuroscience at the IU School of Medicine and attending psychiatrist and research and development investigator at the Richard L. Roudebush Veterans Affairs Medical Center in Indianapolis, said he believes the results provide a first “proof of principle” for a test that could provide an early warning of somebody being at higher risk for an impulsive suicide act.”Suicide is a big problem in psychiatry. It’s a big problem in the civilian realm, it’s a big problem in the military realm and there are no objective markers,” said Dr. Niculescu, director of the Laboratory of Neurophenomics at the Institute of Psychiatric Research at the IU School of Medicine.”There are people who will not reveal they are having suicidal thoughts when you ask them, who then commit it and there’s nothing you can do about it. We need better ways to identify, intervene and prevent these tragic cases,” he said.Over a three-year period, Niculescu and his colleagues followed a large group of patients diagnosed with bipolar disorder, completing interviews and taking blood samples every three to six months. The researchers conducted a variety of analyses of the blood of a subset of participants who reported a dramatic shift from no suicidal thoughts to strong suicidal ideation. They identified differences in gene expression between the “low” and “high” states of suicidal thoughts and subjected those findings to a system of genetic and genomic analysis called Convergent Functional Genomics that identified and prioritized the best markers by cross-validation with other lines of evidence.The researchers found that the marker SAT1 and a series of other markers provided the strongest biological “signal” associated with suicidal thoughts.Next, to validate their findings, working with the local coroner’s office, they analyzed blood samples from suicide victims and found that some of same top markers were significantly elevated.Finally, the researchers analyzed blood test results from two additional groups of patients and found that high blood levels of the biomarkers were correlated with future suicide-related hospitalizations, as well as hospitalizations that had occurred before the blood tests.”This suggests that these markers reflect more than just a current state of high risk, but could be trait markers that correlate with long term risk,” said Dr. …

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Bee venom: Biophysicists zoom in on pore-forming toxin

Aug. 14, 2013 — A new study by Rice University biophysicists offers the most comprehensive picture yet of the molecular-level action of melittin, the principal toxin in bee venom. The research could aid in the development of new drugs that use a similar mechanism as melittin’s to attack cancer and bacteria.The study appears this week in the Proceedings of the National Academy of Sciences.Melittin does its damage by penetrating the outer walls of cells and opening pores that allow the contents of the cell to escape. At low concentrations, melittin forms transient pores. At higher concentrations, the pores become stable and remain open, and at still higher doses, the cell membrane dissolves altogether.”This strategy of opening holes in the cell membrane is employed by a great number of host-defense antimicrobial peptides, many of which have been discovered over the past 30 years,” said Rice’s Huey Huang, the lead investigator of the study. “People are interested in using these peptides to fight cancer and other diseases, in part because organisms cannot change the makeup of their membrane, so it would be very difficult for them to develop resistance to such drugs.”But the clinical use of the compounds is complicated by the lack of consensus about how the peptides work. For example, scientists have struggled to explain how different concentrations of melittin could yield such dramatically different effects, said Huang, Rice’s Sam and Helen Worden Professor of Physics and Astronomy.In the new study, Huang and Rice graduate student Tzu-Lin Sun partnered with colleagues Ming-Tao Lee at the National Synchrotron Radiation Research Center (NSRRC) in Hsinchu, Taiwan, and with Wei-Chin Hung at the Republic of China Military Academy in Fengshan, Taiwan. The team used a combination of experiments to zero in on the molecular activity of melittin at the “minimal inhibitory concentration” (MIC), the lowest concentration that’s been shown to slow the growth of target cell populations. The MIC for melittin is a dose that results in stable pore formation, rather than complete dissolution of the membrane.”We want to understand how pore formation works at this critical concentration, including both at the molecular scale — what are the shapes of the pores themselves — and the cellular scale — how are the pores arranged and distributed over the surface of the membrane,” Huang said.To find the answer, the team correlated the results of two different types of experiments. In the first type, which was conducted at Rice, the team used confocal microscopy to film “giant unilamellar vesicles” (GUVs), synthetic membrane-enclosed structures that are about the same size as a living cell. …

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Bee venom: Biophysicists zoom in on pore-forming toxin

Aug. 14, 2013 — A new study by Rice University biophysicists offers the most comprehensive picture yet of the molecular-level action of melittin, the principal toxin in bee venom. The research could aid in the development of new drugs that use a similar mechanism as melittin’s to attack cancer and bacteria.The study appears this week in the Proceedings of the National Academy of Sciences.Melittin does its damage by penetrating the outer walls of cells and opening pores that allow the contents of the cell to escape. At low concentrations, melittin forms transient pores. At higher concentrations, the pores become stable and remain open, and at still higher doses, the cell membrane dissolves altogether.”This strategy of opening holes in the cell membrane is employed by a great number of host-defense antimicrobial peptides, many of which have been discovered over the past 30 years,” said Rice’s Huey Huang, the lead investigator of the study. “People are interested in using these peptides to fight cancer and other diseases, in part because organisms cannot change the makeup of their membrane, so it would be very difficult for them to develop resistance to such drugs.”But the clinical use of the compounds is complicated by the lack of consensus about how the peptides work. For example, scientists have struggled to explain how different concentrations of melittin could yield such dramatically different effects, said Huang, Rice’s Sam and Helen Worden Professor of Physics and Astronomy.In the new study, Huang and Rice graduate student Tzu-Lin Sun partnered with colleagues Ming-Tao Lee at the National Synchrotron Radiation Research Center (NSRRC) in Hsinchu, Taiwan, and with Wei-Chin Hung at the Republic of China Military Academy in Fengshan, Taiwan. The team used a combination of experiments to zero in on the molecular activity of melittin at the “minimal inhibitory concentration” (MIC), the lowest concentration that’s been shown to slow the growth of target cell populations. The MIC for melittin is a dose that results in stable pore formation, rather than complete dissolution of the membrane.”We want to understand how pore formation works at this critical concentration, including both at the molecular scale — what are the shapes of the pores themselves — and the cellular scale — how are the pores arranged and distributed over the surface of the membrane,” Huang said.To find the answer, the team correlated the results of two different types of experiments. In the first type, which was conducted at Rice, the team used confocal microscopy to film “giant unilamellar vesicles” (GUVs), synthetic membrane-enclosed structures that are about the same size as a living cell. …

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Flex plan for physically demanding jobs: Flexibility tests are often as good as strength tests, and not as discriminatory

July 22, 2013 — Physical fitness tests that focus on sheer strength and endurance may not be the most accurate ways to determine qualified applicants for physically demanding jobs and may also increase the likelihood of a gender discrimination lawsuit from female applicants, according to new research from the University of Iowa.The study, from the Tippie College of Business, suggests instead that in addition to strength and endurance tests, employers should give tests that measure flexibility, balance, coordination, and other forms of movement quality. The study suggests those tests are strong predictors of performance in physically demanding jobs with results that show little difference between genders.More than 28 percent of Americans today work in physically taxing jobs such as law enforcement, firefighting, construction, maintenance, or the military, so fitness screening is an increasingly important part of the hiring process.However, physical ability tests are also highly litigious because most male applicants are physically stronger than women when it comes to muscular strength and endurance and thus score higher on those tests. This adverse impact against women leads to physical ability tests being the third highest cause of workplace discrimination suits in Federal courts.In the study, the research team reviewed 140 past studies of differences in various physical abilities between men and women. Their review showed that men were, indeed, physically stronger than women, but found distinct nuances in other differences.For instance, while it found tests that measured brute muscle strength or cardiovascular endurance favored men, the gender gap was significantly less in tests that measured quality of body movement. In fact, for tests measuring flexibility and balance, the difference was essentially zero.The analysis also found that increased training improved scores for women, but scores for men also increased at a rate that maintained the gender gap; in cardiovascular endurance, the gap actually increased.The study suggests employers that want to reduce the gender gap in physically demanding jobs — and the chance of a discrimination lawsuit — use fitness tests that emphasize movement quality, especially flexibility. The researchers say many jobs could be filled using flexibility tests in addition to strength or endurance tests, giving more women an equal chance at the job and reducing the odds of a lawsuit.Furthermore, the researchers say employers could establish minimum cut-off scores on physical ability tests to establish a pool of candidates and then provide additional training to applicants to help more women get above that cut-off.Beyond the implications of physical ability in the traditional workplace, the researchers say the study of sex differences is especially relevant at present, with combat roles having recently been opened to military women, who comprise more than 10 percent of active-duty personnel in the U.S. military.

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Military sonar can alter blue whale behavior: Human-made noises cause ocean giants to move away from feeding spots

July 3, 2013 — Some blue whales off the coast of California change their behavior when exposed to the sort of underwater sounds used during U.S. military exercises. The whales may alter diving behavior or temporarily avoid important feeding areas, according to new research.The Southern California Behavioral Response Study exposed tagged blue whales in the California Bight to simulated mid-frequency (3.5-4 kHz) sonar sounds significantly less intense than the military uses.”Whales clearly respond in some conditions by modifying diving behavior and temporarily avoiding areas where sounds were produced,†said lead author Jeremy Goldbogen of Cascadia Research. “But overall the responses are complex and depend on a number of interacting factors,” including whether the whales were feeding deep, shallow or not at all.The study, funded by the U.S. Navy Chief of Naval Operations Environmental Readiness Division and the U.S. Office of Naval Research, appears July 3 in the Proceedings of the Royal Society B.The scientists tagged the whales with non-invasive suction cups, which recorded acoustic data and high-resolution movements as the animals were exposed to the controlled sounds.”The tag technology we use offers a unique glimpse into the underwater behavior of whales that otherwise would not be possible,” said Ari Friedlaender, a research scientist at the Duke Marine Laboratory.aThe scientists found that some of the whales engaged in deep feeding stopped eating and either sped up or moved away from the source of the noise. Not all of the whales responded to the noise, and not all in the same way.”Blue whales are the largest animals that have ever lived. Populations globally remain at a fraction of their former numbers prior to whaling, and they appear regularly off the southern California coast, where they feed,” said John Calambokidis, one of the project’s lead investigators of Cascadia Research.That area of the ocean is also the site of military training and testing exercises that involve loud mid-frequency sonar signals. Such sonar exercises have been associated with several unusual strandings of other marine mammal species (typically beaked whales) in the past. Until this study, almost no information was available about whether and how blue whales respond to sonar.”These are the first direct measurements of individual responses for any baleen whale species to these kinds of mid-frequency sonar signals,” said Brandon Southall, SOCAL-BRS chief scientist from SEA, Inc., and an adjunct researcher at both Duke and the University of California Santa Cruz. …

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