scientific research and advances

“Antibiogram” use in nursing facilities could help improve antibiotic use, effectiveness

PORTLAND, Ore. – Use of “antibiograms” in skilled nursing facilities could improve antibiotic effectiveness and help address problems with antibiotic resistance that are becoming a national crisis, researchers conclude in a new study.

Antibiograms are tools that aid health care practitioners in prescribing antibiotics in local populations, such as a hospital, nursing home or the community. They are based on information from microbiology laboratory tests and provide information on how likely a certain antibiotic is to effectively treat a particular infection.

The recent research, published by researchers from Oregon State University in Infection Control and Hospital Epidemiology, pointed out that 85 percent of antibiotic prescriptions in the skilled nursing facility residents who were studied were made “empirically,” or without culture data to help determine what drug, if any, would be effective.

Of those prescriptions, 65 percent were found to be inappropriate, in that they were unlikely to effectively treat the target infection.

By contrast, use of antibiograms in one facility improved appropriate prescribing by 40 percent, although due to small sample sizes the improvement was not statistically significant.

“When we’re only prescribing an appropriate antibiotic 35 percent of the time, that’s clearly a problem,” said Jon Furuno, lead author on the study and an associate professor in the Oregon State University/Oregon Health & Science University College of Pharmacy.

“Wider use of antibiograms won’t solve this problem, but in combination with other approaches, such as better dose and therapy monitoring, and limiting use of certain drugs, we should be able to be more effective,” Furuno said.

“And it’s essential we do more to address the issues of antibiotic resistance,” he said. “We’re not keeping up with this problem. Pretty soon, there won’t be anything left in the medical cabinet that works for certain infections.”

In September, President Obama called antibiotic resistant infections “a serious threat to public health and the economy,” and outlined a new national initiative to address the issue. The Centers for Disease Control and Prevention has concluded that the problem is associated with an additional 23,000 deaths and 2 million illnesses each year in the U.S., as well as up to $55 billion in direct health care costs and lost productivity.

Antibiograms may literally be pocket-sized documents that outline which antibiotics in a local setting are most likely to be effective. They are often used in hospitals but less so in other health care settings, researchers say. There are opportunities to increase their use in nursing homes but also in large medical clinics and other local health care facilities for outpatient treatment. The recent study was based on analysis of 839 resident and patient records from skilled nursing and acute care facilities.

“Antibiograms help support appropriate and prudent antibiotic use,” said Jessina McGregor, also an associate  professor in the OSU/OHSU College of Pharmacy, and lead author on another recent publication on evaluating antimicrobial programs.

“Improved antimicrobial prescriptions can help save lives, but they also benefit more than just an individual patient,” McGregor said. “The judicious use of antibiotics helps everyone in a community by slowing the spread of drug-resistant genes. It’s an issue that each person should be aware of and consider.”

Multi-drug resistant organisms, such as methicillin-resistant Staphylococcus aureus, or MRSA, and other bacterial attacks that are being called “superinfections” have become a major issue.

Improved antibiotic treatment using a range of tactics, researchers say, could ultimately reduce morbidity, save money and lives, and improve patients’ quality of life.

The research led by Furuno was supported by the U.S. Department of Health and Human Services. Collaborators include researchers from the University of Maryland School of Medicine, Denver Health and Hospital Authority, University of Colorado Health Sciences Center, and Agency for Healthcare Research and Quality in Maryland.

Media Contact: 

Jon Furuno, 503-418-9361

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PNAS Commentary: Study sheds new light on sea level rise at last ice age

CORVALLIS, Ore. – A new study published last week in Proceedings of the National Academy of Sciences calculated global sea level changes over the past 35,000 years, concluding that in order to account for the amount of sea level lowering at the peak of the last ice age, much more ice would have had to have been tied up on land than previously thought.

The researchers further concluded that most of this “excess ice” – or an amount greater than today – was likely added to the present Antarctic ice sheets. Lead researcher Kurt Lambeck from Australian National University and colleagues estimated that during the last glacial maximum, these ice sheets had enough excess ice to increase global sea levels some 25 meters, much more than the 10-meter excess scientists previously estimated.

These new findings are critical to understanding the sources of sea level rise that is taking place today in response to a warming climate, according to Peter Clark, an Oregon State University paleoclimatologist, who co-authored a commentary piece on the research in the latest edition of PNAS, which will be published this week.

“Essentially, this new study implies that the Antarctic ice sheets are losing less mass today than had previously been estimated through satellite measurements,” said Clark, a professor in OSU’s College of Earth, Ocean, and Atmospheric Sciences. “During the last ice age, the ice sheets were so large and heavy they pushed the entire land mass down and displaced the viscous mantle below.

“As the ice sheets began to retreat, the land mass beneath began to rise due to the area below being refilled by the mantle as it slowly flows back,” Clark added. “This process is continuing today and needs to be accounted for when estimating from satellites current mass loss from the Antarctic ice sheets. If the effect of this process is bigger than previously thought, then current mass loss is less than we thought.

“If this is the case, then at least some of the rising sea level today that is being attributed to loss of the Antarctic ice sheets must have some other source.”

The other main sources of sea level rise today are from the loss of the Greenland ice sheets, receding glaciers on a global basis, and the expansion of the ocean itself through warming.

Studies show that sea level today is rising globally at a rate of about 3.0 millimeters a year, and about 1/10th of that (0.3 mm) was thought to be from Antarctica.

“If this new study holds up, that means that the rate of contribution from Antarctica to today’s rise is less than 0.3 millimeters,” Clark said. “Learning the source of the increase will help us better understand how sea level rise may play out in the future.”

Prior to Lambeck’s study, the prevailing theory among many scientists was that Antarctic ice sheets contained enough ice to raise global sea levels about 70 meters if it had melted all at once some 21,000 years ago. These ice sheets today hold enough water to raise sea levels 60 meters – about 10 meters less than during the last glacial maximum.

But the study by Lambeck and colleagues, which was based on a comprehensive analysis of nearly 1,000 paleo-sea level markers, suggests instead that the Antarctic had enough mass during the last ice age to raise global sea levels some 85 meters if melted.

In contrast, the entire Greenland ice sheet today contains enough ice to raise global sea levels about seven meters, if melted at once.

Clark, who was a coordinating lead author on sea level rise for the 2013 Intergovernmental Panel on Climate Change (IPCC) report, cautioned that there may be other explanations for the “excess ice” thought to account for the lower sea levels during the last ice age. These might include a greater influence from the lateral viscosity of the Earth’s mantle fluid, the possibility of a large, grounded East Siberian ice sheet, and the influence of physical factors on organisms used as proxies to determine sea level rises.

Lev Tarasov of Memorial University of Newfoundland, co-authored the commentary with Clark.

Media Contact: 

Peter Clark, 541-737-1247; clarkp@geo.oregonstate.edu

“Mild” control of systolic blood pressure in older adults is adequate: 150 is good enough

CORVALLIS, Ore. – A broad review of the use of medications to reduce blood pressure has confirmed that “mild” control of systolic pressure is adequate for adults age 65 or older - in the elderly, there’s no clear benefit to more aggressive use of medications to achieve a lower pressure.

Historically, most medical practitioners tried to achieve control of systolic pressure – the higher of the two blood pressure readings – to 140 or less. Recently changed guidelines now suggest that for adults over 60, keeping the systolic pressure at 150 or less is adequate, and this extensive analysis confirms that.

However, researchers also say in the report that more work needs to be done studying blood pressure in older populations, since most of the research, and the medical guidelines based on them, were done using predominately younger adults.

The review was just published in Drugs & Aging, a professional journal, by scientists from the College of Pharmacy at Oregon State University and Oregon Health & Science University.

“The goal of a systolic pressure at or below 140 has been around a long time, and there’s still skepticism among some practitioners about accepting a higher blood pressure,” said Leah Goeres, an OSU postdoctoral fellow and lead author on the publication.

“Keeping systolic blood pressure in older adults below 150 is important, it’s what we consider a mild level of control,” Goeres said. “But for older people that level is also good enough. After an extensive review, there was no significant evidence that more intensive management is necessary.”

The issue about how low is low enough, researchers say, is important because blood pressure medications can have unwanted side effects that increase as higher dosages of medications are used. The problem is common – in the United States, about 70 percent of adults age 65 or older have hypertension, and millions of people take medication to control it.

One of the more significant side effects is what’s called “orthostatic hypotension,” a condition in which a person’s blood pressure can suddenly fall when they rise or stand, making them feel light-headed or dizzy, and sometimes leading to dangerous falls. More than 30 percent of people over the age of 80 have this problem.

High blood pressure is a serious health concern, but also one of the most treatable with medication, if such things as diet, exercise, weight management or lifestyle change prove inadequate.  Hypertension is often called the “silent killer” because it causes few obvious symptoms, but it weakens blood vessels and has been linked to higher levels of heart attacks, kidney disease and especially stroke.

“There’s clearly a value to controlling blood pressure, enough to keep it at 150 or less,” said David Lee, an OSU assistant professor of pharmacy practice. “Keeping blood pressure within acceptable levels will lower death rates. But as people get older, there’s less clear evidence that stringent control of systolic blood pressure is as important.”

The researchers said a goal for the future should be to do more studies specifically with older adult populations and try to identify health situations and conditions that might benefit from different types of management. Such “individualized” treatments, they said, would consider a person’s entire health situation instead of treating them based on findings made with large groups.

In this study, the researchers did not find that one approach or another to lowering blood pressure stood out and was clearly better than other alternatives. A variety of medications can be used to treat the condition.

Media Contact: 

David Lee, 503-494-2258

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Hygienic funerals, better protection for health workers offer best chance to stop Ebola

CORVALLIS, Ore. – Hygienic funeral practices, case isolation, contact tracing with quarantines, and better protection for health care workers are the keys to stopping the Ebola epidemic that continues to expand in West Africa, researchers said today in a new report in the journal Science.

Continuing the status quo of intervention efforts that were in place as of Sept. 19 would allow continued expansion of the epidemic by about 224 new cases daily in Liberia by Dec. 1, and 348 new daily cases by Dec. 30, the scientists reported in their analysis.

However, they said broad implementation “with utmost urgency” of more aggressive approaches they recommended, used at a reasonably high level of efficiency, could by mid-March lead to its control in Liberia, the focal point of the epidemic.

Researchers from Yale University, Oregon State University, and the Ministry of Health and Social Welfare in Liberia concluded that funerals, as they have been customarily practiced in this region, were what they called “super-spreader events” that have had a disproportionate impact on the early transmission of the virus.

Changes in those practices are the single most important, practical step that could help place the number of new Ebola infections on a downward path. But a whole suite of actions are needed, they cautioned, and reducing transmission in hospitals and the community will not by itself bring the epidemic under control.

“The cultural body preparation and funeral practices that are common in West Africa have driven the initial spread of this disease,” said Jan Medlock, an assistant professor in the OSU Department of Biomedical Sciences and an expert in mathematical epidemiology and evolution of infectious disease.

“These funeral practices often included washing, touching and kissing of bodies that were still capable of spreading the Ebola virus,” Medlock said. “It is imperative that funeral transmission be stopped, and also that we take other aggressive steps to isolate cases and better protect health care workers.”

The findings were made with complex mathematical models that consider many variables in how the disease is spreading, what steps are being taken to slow its progression and how effective those steps are. The research sought to identify not only what would theoretically work, but what was most practical and achievable.

The goal, the researchers said, should be to shift the current Ebola epidemic from one that is expanding to one that is slowly declining – to change what scientists call the “basic reproductive number” to less than 1, so the epidemic is on the road to ultimate extinction. They estimated that in Liberia the Ebola reproductive number is currently 1.63, meaning that two infected people would infect, on average, about three more people, and the epidemic continues to expand.

Getting that reproductive number below 1 will require adequate and proper use of personal protective equipment, more complete case isolations, contact precautions, quarantines, and particularly improved funeral practices. Achieving these goals at a success rate of about 60 percent could ultimately curtail the epidemic, the researchers said.

To arrive at their conclusions, the scientists used mathematical analysis to consider such factors as the density of infected and uninfected people in an area, numbers attending a funeral, those hospitalized, their relatives, health care workers in the hospital, and the general community.

Instead of traditional burial preparations, the researchers endorsed a very hygienic approach that includes disinfecting the cadaver before placing it in a plastic body bag and doing further disinfecting. Human-to-human transmission of Ebola occurs mostly through direct or indirect contact with body fluids, the researchers noted in their report, and deceased victims still carry a high viral load in their blood and excretions.

Another significant concern, the researchers said, is under-reporting of cases, both in hospitals and the general community. This could slow the stoppage of the epidemic and increase the level of intervention needed to stop it.

Other things could also change as the epidemic evolves. Funeral attendance and traditional burial practices may decline as awareness builds about the disease, but contacting people who may have been exposed could become even more difficult as people move from urban to rural areas.

This study was supported by the National Institutes of Health and the Notsew Orm Sands Foundation. It was a collaboration of researchers from the OSU College of Veterinary Medicine, the Yale School of Public Health and the Ministry of Health and Social Welfare in Liberia. The corresponding author was Alison Galvani at the Yale School of Public Health. It is being published in the journal Science at its online Science Express web site.

The findings of this study were specific to Liberia but should have some relevance to other places with similar cultural practices or approaches to disease management, Medlock said. They are less relevant in situations where the disease has spread beyond Africa into the United States, Europe and other parts of the developed world, he said, where aggressive isolation and containment of infected people or quarantine of those exposed is more practical.

Given the magnitude of this health crisis, it’s already apparent that Ebola poses an international threat that requires an international response and aid, the scientists said in their conclusion.

“Ebola poses an urgent threat not only to West Africa but also to the international community,” they wrote.

“The implementation of effective interventions needed to reverse the growth of the Ebola outbreak in impoverished West African countries will be logistically challenging even with substantial international aid, but impossible without it.”

Media Contact: 

Jan Medlock, 541-737-6874

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Running robots of future may learn from world’s best two-legged runners: birds

CORVALLIS, Ore. – With an eye toward making better running robots, researchers have made surprising new findings about some of nature’s most energy-efficient bipeds – running birds.

Although birds are designed primarily for flight, scientists have learned that species that predominately live on land and scurry around on the ground are also some of the most sophisticated runners of any two-legged land animals. These characteristics may have been evolving since the time of the dinosaurs and, some would say, now transcend the ability of other bipedal runners, including humans.

In a study published today in the Journal of Experimental Biology, researchers from Oregon State University, the Royal Veterinary College and other institutions outline how running birds have achieved an impressive ability to run while minimizing energy cost, avoiding falls or injury, and maintaining speed and direction.

“Birds appear to be the best of bipedal terrestrial runners, with a speed and agility that may trace back 230 million years to their dinosaur ancestors,” said Jonathan Hurst, an associate professor and robotics expert in the OSU College of Engineering.

Running birds come in an enormous range of sizes, from tiny quails to an ostrich that has 500 times as much body mass. Most, but not all, can fly, but spend most of their lives on the ground, and they don’t always look the most graceful when they run. But researchers found that they maximize the results while keeping their priorities straight – save energy and don’t break a leg.

In the wild, an injury could lead to predation and death; and in like fashion, when food resources are limited, economy of motion is essential.

“These animals don’t care that they appear a little unstable or have a waver in their gait,” Hurst said. “Their real goal is to limit peak forces, avoid falling, be safe and be as efficient as possible. If their upper body seems to lurch around a little as a result, that’s okay. What they are accomplishing is really quite elegant.”

Even more surprisingly, a wide variety of ground-running bird species with very different body sizes use essentially the same strategy to accomplish these sometimes conflicting tasks. In order to hop over obstacles on uneven ground, they use a motion that’s about 70 percent a “vaulting” movement as they approach the obstacle, and 30 percent a more-crouched posture while on top of the obstacle.

“Evolution has shaped running birds into all different sizes and skeletal structures,” said Christian Hubicki, a doctoral student at Oregon State who co-authored the study. “But we found their behavior in how they run is essentially the same.”

In collaboration with Monica Daley at the Royal Veterinary College in London, the researchers studied five species of birds and developed a computer model in OSU’s Dynamic Robotics Laboratory that closely matches that behavior.

“We should ultimately be able to encode this understanding into legged robots so the robots can run with more speed and agility in rugged terrain,” Hubicki said. “These insights may also help us understand the walking and running behaviors of all the common ancestors involved, including theropod dinosaurs such as the velociraptor.”

The researchers began the study with a hypothesis that body stability would be a priority, since it might help avoid falls and leg injuries. That’s not what they found, however.

Instead, running birds have a different definition of stability – they do avoid falls, but also allow their upper bodies to bounce around some, just so long as they don’t fall. Like a scrambling football runner, their leg motion may sometimes speed up or slow down, in the interest of staying upright, dealing with obstacles and generally staying on course to where they are going. The process isn’t always pretty, but it’s functional.

Large animals are limited by the strength of their legs because peak loads increase with body mass, and they run with somewhat straighter legs to compensate. But the basic approach large birds use to run is similar to much smaller birds, and remains highly efficient.

Modern robots, by contrast, are usually built with an emphasis on total stability, which often includes maintaining a steady gait. This can be energy-intensive and sometimes limits their mobility.

What robots could learn from running birds, the scientists said, is that it’s okay to deviate from normal steady motions, because it doesn’t necessarily mean you’re going to fall or break something. Robotic control approaches “must embrace a more relaxed notion of stability, optimizing dynamics based on key task-level priorities without encoding an explicit preference for a steady gait,” the researchers said in their conclusion.

Collaborators on the research were from the Royal Veterinary College in the United Kingdom. The work was supported by the Biotechnology and Biological Sciences Research Council in the United Kingdom and the Human Frontier Science Program.

“The running robots of the future are going to look a lot less robotic,” Hurst said. “They will be more fluid, like the biological systems in nature. We’re not necessarily trying to copy animals, but we do want to match their capabilities.”

Media Contact: 

Jonathan Hurst, 541-737-7010

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Running turkey

New study shows three abrupt pulse of CO2 during last deglaciation

CORVALLIS, Ore. – A new study shows that the rise of atmospheric carbon dioxide that contributed to the end of the last ice age more than 10,000 years ago did not occur gradually, but was characterized by three “pulses” in which C02 rose abruptly.

Scientists are not sure what caused these abrupt increases, during which C02 levels rose about 10-15 parts per million – or about 5 percent per episode – over a period of 1-2 centuries. It likely was a combination of factors, they say, including ocean circulation, changing wind patterns, and terrestrial processes.

The finding is important, however, because it casts new light on the mechanisms that take the Earth in and out of ice age regimes. Results of the study, which was funded by the National Science Foundation, appear this week in the journal Nature.

“We used to think that naturally occurring changes in carbon dioxide took place relatively slowly over the 10,000 years it took to move out of the last ice age,” said Shaun Marcott, lead author on the article who conducted his study as a post-doctoral researcher at Oregon State University. “This abrupt, centennial-scale variability of CO2 appears to be a fundamental part of the global carbon cycle.”

Some previous research has hinted at the possibility that spikes in atmospheric carbon dioxide may have accelerated the last deglaciation, but that hypothesis had not been resolved, the researchers say. The key to the new finding is the analysis of an ice core from the West Antarctic that provided the scientists with an unprecedented glimpse into the past.

Scientists studying past climate have been hampered by the limitations of previous ice cores. Cores from Greenland, for example, provide unique records of rapid climate events going back 120,000 years – but high concentrations of impurities don’t allow researchers to accurately determine atmospheric carbon dioxide records. Antarctic ice cores have fewer impurities, but generally have had lower “temporal resolution,” providing less detailed information about atmospheric CO2.

However, a new core from West Antarctica, drilled to a depth of 3,405 meters in 2011 and spanning the last 68,000 years, has “extraordinary detail,” said Oregon State paleoclimatologist Edward Brook, a co-author on the Nature study and an internationally recognized ice core expert. Because the area where the core was taken gets high annual snowfall, he said, the new ice core provides one of the most detailed records of atmospheric CO2.

“It is a remarkable ice core and it clearly shows distinct pulses of carbon dioxide increase that can be very reliably dated,” Brook said. “These are some of the fastest natural changes in CO2 we have observed, and were probably big enough on their own to impact the Earth’s climate.

“The abrupt events did not end the ice age by themselves,” Brook added. “That might be jumping the gun a bit. But it is fair to say that the natural carbon cycle can change a lot faster than was previously thought – and we don’t know all of the mechanisms that caused that rapid change.”

The researchers say that the increase in atmospheric CO2 from the peak of the last ice age to complete deglaciation was about 80 parts per million, taking place over 10,000 years. Thus, the finding that 30-45 ppm of the increase happened in just a few centuries was significant.

The overall rise of atmospheric carbon dioxide during the last deglaciation was thought to have been triggered by the release of CO2 from the deep ocean – especially the Southern Ocean. However, the researchers say that no obvious ocean mechanism is known that would trigger rises of 10-15 ppm over a time span as short as one to two centuries.

“The oceans are simply not thought to respond that fast,” Brook said. “Either the cause of these pulses is at least part terrestrial, or there is some mechanism in the ocean system we don’t yet know about.”

One reason the researchers are reluctant to pin the end of the last ice age solely on CO2 increases is that other processes were taking place, according to Marcott, who recently joined the faculty of the University of Wisconsin-Madison.

“At the same time CO2 was increasing, the rate of methane in the atmosphere was also increasing at the same or a slightly higher rate,” Marcott said. “We also know that during at least two of these pulses, the Atlantic Meridional Overturning Circulation changed as well. Changes in the ocean circulation would have affected CO2 – and indirectly methane, by impacting global rainfall patterns.”

“The Earth is a big coupled system,” he added, “and there are many pieces to the puzzle. The discovery of these strong, rapid pulses of CO2 is an important piece.”

Media Contact: 

Shaun Marcott, smarcott@wisc.edu;

Ed Brook, 541-737-8197, brooke@geo.oregonstate.edu

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(Feature photo at left) - Donald Voigt from Penn State looks at an ice core in January 2012 during the WAIS Divide project. Photo courtesy of Gifford Wong, Dartmouth








OSU scientists have examined air bubbles trapped in a new ice core that are providing them with some of the clearest indications of atmospheric conditions during the last ice age.

Oral contraception may become renewed option for HIV-positive women

CORVALLIS, Ore. – Contrary to guidelines issued by the World Health Organization, new research has found that HIV-positive women receiving one of the most common forms of drug therapy should be able to use at least some forms of oral contraceptives for birth control.

The findings, just published in the journal Contraception, may lead to new options of birth control for women with HIV. Further research should be done to confirm that clinical outcomes are consistent with conclusions that have been based on pharmacokinetic analysis, scientists said.

Worldwide, the leading cause of death among women ages 18-45 is HIV/AIDS, and prevention of mother-to-child transmission of HIV by reducing unintended pregnancy is a United Nations millennium goal for 2010-15. This research, and broad access to oral contraception, could help reach that goal.

The research was done by scientists from the Oregon State University/Oregon Health & Science University College of Pharmacy, the Albert Einstein College of Medicine and the University of Southern California.

Although millions of women around the world routinely use oral contraception, it has been largely avoided by those with HIV infections because some of the drugs commonly used to control HIV are believed to reduce the effectiveness of birth control pills.

Because of that, both the World Health Organization and Centers for Disease Control have suggested that oral contraceptives should not be used by HIV-positive women if other methods of birth control are available – such as barrier devices, IUDs or other approaches.

The new study, however, raises doubts about such a broad guideline against oral contraception. It found that while some types of oral contraceptives may be subject to this concern, others that are highly efficacious should be even more effective when particular HIV drugs are used.

“Oral contraception is used by millions of women and is among the most popular forms of birth control,” said Ganesh Cherala, an OSU assistant professor of pharmacy practice, a corresponding author on the study. Cherala is an expert in pharmacokinetics, or how drugs behave, interact and are transformed in the body.

“It’s important for women to have access to – and the ability to choose from – as wide a range of birth control options as possible,” Cherala said. “We believe this research shows the WHO guidelines are too generic and unnecessarily cautious. There clearly appear to be oral contraceptives that should be safe and effective in women being treated with HIV medications.”

In general, there are two types of oral contraceptives: “combination” drugs that include both estrogen and progestin, and drugs that are based solely on progestin for their efficacy. The concerns raised about reduced efficacy were based primarily on studies of the combination oral contraceptives, and may be valid for that group of drugs, Cherala said.

However, the new study found that progestin-only contraceptives based on at least one progestin, norethindrone, should actually have a slightly higher level of birth control efficacy, not a reduced one, when a women is taking one of the primary therapies for HIV, called a ritonavir-boosted atazanavir antiretroviral therapy.

Other progestin-only birth control drugs may also have the same properties as the ones based on norethindrone, but that has not yet been conclusively demonstrated, Cherala said. 

The research was done with both treatment and control groups of women who were HIV-positive, ages 18-44, with no other recent use of hormonal contraception.

“These findings are interesting and exciting,” Cherala said. “They should ultimately give women more options to consider for birth control.”

Historically, some of the progestin-only oral contraceptives had unwanted side effects more than the combination contraceptives, Cherala said. However, those differences are now very small as improved forms of progestin-only contraceptives have come to market.

This research was supported by the National Institutes of Health.

Media Contact: 

Ganesh Cherala, 503-418-0447

Study: Could sleeper sharks be preying on protected Steller sea lions?

NEWPORT, Ore. – Pacific sleeper sharks, a large, slow-moving species thought of as primarily a scavenger or predator of fish, may be preying on something a bit larger – protected Steller sea lions in the Gulf of Alaska.

A new study found the first indirect evidence that this cold-blooded shark that can grow to a length of more than 20 feet – longer than a great white shark – may be an opportunistic predator of juvenile Steller sea lions.

Results of the study have just been published in the journal Fishery Bulletin. The findings are important, scientists say, because of management implications for the protected Steller sea lions.

For the past decade, Markus Horning of the Marine Mammal Institute at Oregon State University has led a project in collaboration with Jo-Ann Mellish of the Alaska SeaLife Center to deploy specially designed “life history transmitters” into the abdomens of juvenile Steller sea lions. These buoyant archival tags record data on temperature, light and other properties during the sea lions’ lives and after the animals die the tags float to the surface or fall out ashore and transmit data to researchers via satellite.

From 2005-11, Horning and his colleagues implanted tags into 36 juvenile Steller sea lions and over a period of several years, 17 of the sea lions died. Fifteen transmitters sent data indicating the sea lions had been killed by predation.

“The tags sense light and air to which they are suddenly exposed, and record rapid temperature change,” said Horning, who is in OSU’s Department of Fisheries and Wildlife. “That is an indication that the tag has been ripped out of the body, though we don’t know what the predator is that did this.

“At least three of the deaths were different,” he added. “They recorded abrupt temperature drops, but the tags were still dark and still surrounded by tissue. We surmise that the sea lions were consumed by a cold-blooded predator because the recorded temperatures aligned with the deep waters of the Gulf of Alaska and not the surface waters.

“We know the predator was not a killer whale, for example, because the temperatures would be much higher since they are warm-blooded animals.” Data collected from the transmitters recorded temperatures of 5-8 degrees Celsius.

That leaves a few other suspects, Horning said. However, two known predators of sea lions – great white sharks and salmon sharks – have counter-current heat exchanges in their bodies that make them partially warm-blooded and the tags would have reflected higher temperatures.

By process of elimination, Horning suspects sleeper sharks.

The Oregon State pinniped specialist acknowledges that the evidence for sleeper sharks is indirect and not definitive, thus he is planning to study them more closely beginning in 2015. The number of sleeper sharks killed in Alaska as bycatch ranges from 3,000 to 15,000 annually, indicating there are large numbers of the shark out there. The sleeper sharks caught up in the nets are usually comparatively small; larger sharks are big enough to tear the fishing gear and are rarely landed.

“If sleeper sharks are involved in predation, it creates something of a dilemma,” said Horning, who works out of OSU’s Hatfield Marine Science Center in Newport, Ore. “In recent years, groundfish harvests in the Gulf of Alaska have been limited in some regions to reduce the potential competition for fish that would be preferred food for Steller sea lions.

“By limiting fishing, however, you may be reducing the bycatch that helps keep a possible limit on a potential predator of the sea lions,” he added. “The implication could be profound, and the net effect of such management actions could be the opposite of what was intended.”

Other studies have found remains of Steller sea lions and other marine mammals in the stomachs of sleeper sharks, but those could have been the result of scavenging instead of predation, Horning pointed out.

The western distinct population of Steller sea lions has declined to about 20 percent of the levels they were at prior to 1975.

Media Contact: 

Markus Horning, 541-867-0270, markus.horning@oregonstate.edu

Scientists discover carbonate rocks are unrecognized methane sink

CORVALLIS, Ore. – Since the first undersea methane seep was discovered 30 years ago, scientists have meticulously analyzed and measured how microbes in the seafloor sediments consume the greenhouse gas methane as part of understanding how the Earth works.

The sediment-based microbes form an important methane “sink,” preventing much of the chemical from reaching the atmosphere and contributing to greenhouse gas accumulation. As a byproduct of this process, the microbes create a type of rock known as authigenic carbonate, which while interesting to scientists was not thought to be involved in the processing of methane.

That is no longer the case. A team of scientists has discovered that these authigenic carbonate rocks also contain vast amounts of active microbes that take up methane. The results of their study, which was funded by the National Science Foundation, were reported today in the journal Nature Communications.

“No one had really examined these rocks as living habitats before,” noted Andrew Thurber, an Oregon State University marine ecologist and co-author on the paper. “It was just assumed that they were inactive. In previous studies, we had seen remnants of microbes in the rocks – DNA and lipids – but we thought they were relics of past activity. We didn’t know they were active.

“This goes to show how the global methane process is still rather poorly understood,” Thurber added.

Lead author Jeffrey Marlow of the California Institute of Technology and his colleagues studied samples from authigenic compounds off the coasts of the Pacific Northwest (Hydrate Ridge), northern California (Eel River Basin) and central America (the Costa Rica margin). The rocks range in size and distribution from small pebbles to carbonate “pavement” stretching dozens of square miles.

“Methane-derived carbonates represent a large volume within many seep systems and finding active methane-consuming archaea and bacteria in the interior of these carbonate rocks extends the known habitat for methane-consuming microorganisms beyond the relatively thin layer of sediment that may overlay a carbonate mound,” said Marlow, a geobiology graduate student in the lab of Victoria Orphan of Caltech.

These assemblages are also found in the Gulf of Mexico as well as off Chile, New Zealand, Africa, Europe – “and pretty much every ocean basin in the world,” noted Thurber, an assistant professor (senior research) in Oregon State’s College of Earth, Ocean, and Atmospheric Sciences.

The study is important, scientists say, because the rock-based microbes potentially may consume a huge amount of methane. The microbes were less active than those found in the sediment, but were more abundant – and the areas they inhabit are extensive, making their importance potential enormous. Studies have found that approximately 3-6 percent of the methane in the atmosphere is from marine sources – and this number is so low due to microbes in the ocean sediments consuming some 60-90 percent of the methane that would otherwise escape.

Now those ratios will have to be re-examined to determine how much of the methane sink can be attributed to microbes in rocks versus those in sediments. The distinction is important, the researchers say, because it is an unrecognized sink for a potentially very important greenhouse gas.

“We found that these carbonate rocks located in areas of active methane seeps are themselves more active,” Thurber said. “Rocks located in comparatively inactive regions had little microbial activity. However, they can quickly activate when methane becomes available.

“In some ways, these rocks are like armies waiting in the wings to be called upon when needed to absorb methane.”

The ocean contains vast amounts of methane, which has long been a concern to scientists. Marine reservoirs of methane are estimated to total more than 455 gigatons and may be as much as 10,000 gigatons carbon in methane. A gigaton is approximate 1.1 billion tons.

By contrast, all of the planet’s gas and oil deposits are thought to total about 200-300 gigatons of carbon.

Media Contact: 

Andrew Thurber, 541-737-4500, athurber@coas.oregonstate.edu

Educated community no protection against a poor diet for children


CORVALLIS, Ore. – A study of elementary school children in a highly educated community in the Pacific Northwest found that about three fourths of the students had vitamin D levels that were either insufficient or deficient, and they also lacked an adequate intake of other important nutrients.

The findings, reported recently in the Journal of Extension by scientists from the Linus Pauling Institute at Oregon State University, make it clear that nutritional deficiencies can be profound even in communities with a very knowledgeable population and easy access to high quality, affordable food.

Many other studies have found similar concerns in areas with low socioeconomic status, poor food availability, and lower levels of education. This research identified significant nutritional problems in Corvallis, Ore., a university town with many grocery stores, a free bus transit system and some of the highest educational levels in the nation. In Corvallis, 26 percent of residents have completed a graduate degree, which is more than double the national average.

As students grew from younger children into adolescents, the problems only got worse, the research showed. The trend continued toward a diet focused on simple carbohydrates, and low both in fiber and important micronutrients.

“It’s becoming increasingly clear that health and dietary concerns cut across all populations, including comparatively well-educated or affluent groups,” said Gerd Bobe, an assistant professor with the OSU College of Agricultural Sciences and member of the Healthy Youth Program at the Linus Pauling Institute.

“This research also showed nutritional status and dietary choices are getting worse as students become teenagers,” Bobe said. “The foundation for lifelong health is laid in childhood, and puberty is a critical time for growth, brain and bone development. It’s a really bad time to have a bad diet. Since Corvallis is a very educated community with many health-conscious individuals, this is an illustration of just how widespread these problems are.”

The study focused some of its attention on vitamin D, taking blood samples from 71 students at four public elementary schools in Corvallis. They found about 8 percent of students were outright deficient in this vitamin, and about 69 percent were “insufficient,” defined as a level that’s less than ideal for optimal health.

Vitamin D is important for immune function; brain, muscle and bone development and health; and prevention of chronic diseases, including diabetes and cancer. It is often found to be deficient in many temperate zones where people don’t get adequate sun exposure.

The study examined children in two age groups, 5-8 years old and 9-11 years. The older children had even lower vitamin D levels that the younger group, correlated to a lower consumption of dairy products.

Based on their findings, the researchers suggested that educational or outreach programs to improve nutrition understanding are needed in a broad cross section of society, not just low-income or underserved groups.

“Studies show that children and adults both learn best when all their senses are involved, through something like cooking classes combined with nutrition education,” said Simone Frei, manager of the Healthy Youth Program at the Linus Pauling Institute.

“In our classes, youth and families learn about eating plenty of fresh fruits and vegetables, whole grain foods and reducing processed foods,” Frei said. “This is even more effective when combined with growing and harvesting fresh vegetables from the garden.”

This program, among other initiatives, operates a “Chefs in the Garden” summer camp, and data show that 65 percent of participating children increased their vegetable consumption after the camp experience.

Among the other findings of the study:

  • Most of the children reported a diet insufficient in fiber and essential fatty acids;
  • Nearly all children consumed less potassium and more sodium than recommended, a health habit that ultimately can be associated with higher levels of chronic diseases, including heart disease and cancer;
  • Only a single child in the entire study group reported a diet that would provide adequate intake of vitamin E, which is important for neurological development, cognition and anemia prevention.

As a result of the study, educational programs were developed by the Healthy Youth Program at OSU, some of which are available online at http://bit.ly/1ukBNnT

Media Contact: 

Gerd Bobe, 541-737-1898

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Learning to garden
Learning to garden

A healthy feast
A healthy feast