Duke Research Blog

Following the people and events that make up the research community at Duke.

Author: Ashley Mooney (Page 1 of 5)

Cooking up a new approach to heart disease in rural China

By Ashley Mooney

As cardiovascular disease becomes more prevalent in China, researchers look to change cooking practices that may be putting people at higher risk.

Currently, the top two causes of death in China are cardiovascular disease and chronic obstructive pulmonary disease, meaning that cardiovascular interventions will become increasingly important in public health, Assistant McGill University professor Jill Baumgartner said in a March 21 lecture. Environmental pollution from industry, increasing vehicle pollution, tobacco smoke and biomass usage have contributed to China’s shift in disease burden.

Typical gasifiers in China. Slide created by , photo taken by Ashley Mooney.

Typical gasifiers in China. Slide created by Jill Baumgartner, photo taken by Ashley Mooney.

“There’s been massive changes in China since the 1970s, they’ve brought in economic and social reforms. You see these massive increases in [gross domestic product] per capita as well as life expectancy,” she said. “[As a result], there’s been this shift from nutritional or infectious disease-related deaths in China… to chronic diseases.”

Many across the globe use gasifier stoves to cook, which use wood or coal as fuel and emit more carbon monoxide than electric alternatives. These emissions are not only harmful to the environment, but chronic exposure can lead to an increase in systolic blood pressure—a marker for increased risk of cardiovascular disease.

“Globally, about half the world’s population is using biomass and coal as their primary energy source,” Baumgartner said. “In China it’s just under 50 percent of the population.”

Baumgartner primarily studied women who have never smoked cigarettes in Yunnan, a southern province of China. Culturally, women from this area rarely smoke, while men often do, she said. The women are also the primary cooks for the family, meaning they spend the most time near biomass-burning stoves and space heaters and are ideal study subjects for the effects of the biomass without the confounds of smoking.

By measuring particulate matter, black carbon and water-soluble organic carbon, Baumgartner determined women’s seasonal exposure to biomass and its effect on their blood pressure. Black carbon is associated with regional climate warming and is used as an indicator of combustion particulate matter and water-soluble organic carbon is an indicator of biomass particulate matter.

“When we think about climate change and other greenhouse gasses, the effects are going to be really long term,” Baumgartner said. “But black carbon is unique because if you turn off black carbon, it’s kind of like turning off the tap. So you stop black carbon from entering the atmosphere and the warming effect decreases in weeks.”

While Baumgartner’s research initially looked at only the effects of biomass burning on cardiovascular health, she is transitioning to work on interventions. Since the beginning of her work in Yunnan, engineers have built a biomass-pellet manufacturing site, which provides more efficient and less toxic fuel for locals.

Baumgartner said interventions leading to a 8mm Hg decrease in systolic blood pressure could translate to a 29 percent decrease in coronary heart disease and 38 percent decrease in the onset of strokes.

Music, the Brain and Jimi Hendrix

By Ashley Mooney

Hearing music and moving to it are more connected than you’d think. 

Richard Mooney and one of his research subjects. (Photo - Duke Magazine)

Richard Mooney and one of his research subjects. (Photo – Duke Magazine)

Neurobiologists have traditionally viewed human responses to sound as reflexive.

But in fact, perception of sound and music can be viewed as much more dynamic, said Richard Mooney, George Barth Geller professor of neurobiology and classically-trained guitarist. Rather than speaking in a typical lecture hall, Mooney presented his research in Motorco Music Hall.

“In the classic view of how the nervous system works, there’s a sensory stimulus in the world that excites our sensory receptors and then we behave,” Mooney said. “This can’t be so. We don’t live in a reflexive experience. We’re living in a state where we’re present in the moment.”

Using a video of musician Jimi Hendrix’s performance of “Johnny B. Goode,” Mooney illustrated the connection between the motor system and the auditory cortex.

“Hendrix is anticipating all these dynamics in music, moving his body in a way to accentuate it,” Mooney said. “It’s a really good example of how our brain must be forecasting the sound it wants to make or the sound it wants to experience.”

Mooney cited a study in which trained keyboard players were asked either to listen to music without making physical movements or to play a piece without being able to hear it. Using functional MRI, researchers found that the auditory cortex, the supplementary motor area and the premotor cortex of the brain all receive more oxygen than other sections during either task, implying a connection between the systems.

“Music isn’t passive. Even when we’re listening, it’s engaging not only the biological amplifier in our ear, but also this really complex network of sensory motor structures in our brain,” Mooney said.

800px-Uncoiled_cochlea_with_basilar_membrane

An uncoiled cochlea with the basilar membrane. Courtesy of Wikimedia commons.

A part of the inner ear called the cochlea functions as an acoustical prism, splitting complex sounds into an array of simpler, tone-like components.

“The lens of our eye focuses stimuli in a way that’s Cartesian,” Mooney said. “In contrast, what our ear has to do is really take a mismatched pattern of energy that’s vibrating in our eardrum and decompose it into simpler components.”

People have biological amplifiers deep in their cochlea that allow them to perceive and interpret speech and music. Average-volume speech usually causes the basilar membrane, a structure in the inner ear, to vibrate within a very small distance—approximately the diameter of a gold atom. Mooney noted that the level of vibration indicates that the membrane moves about 100-fold more than it would if the system were purely passive.

The cochlea even vibrates in deaf ears, just not to the same extent. But much of a person’s ability to hear, that is to discern differences in pitch and the nuances of spoken language, also rely on hair cells within the ear.

“These aren’t the things responsible for your grandfather’s tufts of hair that are coming out of his ears,” Mooney said. “These are all a special kind of nerve cell called a receptor cell.”

Even though all people have connections between their motor and auditory systems and may understand the connections conceptually, musicians and those who frequently practice making music can usually predict upcoming tones with more accuracy.

He provided the example of basketball players shooting free throws. If shown video clips of a person shooting a free throw, but not the final trajectory, only professional players can accurately predict whether the ball went into the basket. Sportscasters and audience members cannot accurately predict baskets, even if they are highly exposed to watching the actions.

BAW logoThe lecture was part of Brain Awareness Week, a global campaign to encourage public interest in the progress and benefits of brain research. Mooney noted that Brain Awareness Week helps him gain a different perspective on his research.

“Scientists hang out with themselves in their labs and they ask each other these really sort of pointy headed questions all the time,” he said. “They don’t get a lot of chances to hear from people who have really different perspectives.”

The final event in the series was a hands-on demonstration at the Museum of Life and Science, Saturday from 1 to 4 p.m.

Inside the Monkey Brain

By Ashley Mooney

Both in the lab and on a tropical island, primate behaviors can shed light on social-decision making.

To fully understand the biology of social-decision making, Michael Platt, director of the Duke Institute for Brain Science, conducts lab work at Duke and field research an island off the coast of Puerto Rico called Cayo Santiago. His research focuses on understanding both the physiological and social aspects of decision making.

“Our brains are exquisitely tuned to making [social] decisions and acquiring the information to inform them,” Platt said. “When these processes go awry, as occurs in disorders like autism, schizophrenia or anxiety disorders, the consequences can be devastating.”

Courtesy of Lauren Brent.

Courtesy of Lauren Brent.

Platt’s group uses rhesus macaques as model animals because of their strong behavioral, physiological and neurobiological similarity to humans. But understanding how the monkey brain—and thus the human brain—works requires both laboratory-based biological information and social studies in a natural environment.

Researchers can combine the knowledge they gain from lab and field studies to create a holistic picture of the biological basis of behavior, said Lauren Brent, associate research fellow at the University of Exeter who did her post-doc with Platt at Duke.

Lab studies are best suited for quantitative, repeatable studies in which variables can be precisely controlled, Platt said. On the other hand, field studies emphasize external validity and an animal’s response in its natural conditions, but are not suitable for determining precise measurements of internal processes.

In the lab, Platt’s group studies the neural mechanisms that mediate prosocial and antisocial decisions, Platt said. They can also study the ways in which humans can enhance prosocial decisions using pharmacological or behavioral interventions.

On Cayo, the researchers are exploring the genetic factors that shape individual differences in social behavior and decision-making in free-living monkeys. They use observations, behavioral experiments and blood and fecal samples to study the monkeys non-invasively.

“The project on Cayo and the work that goes on the lab are complementary in the best sense because we can do things on Cayo that we can’t do in the lab,” Brent said. “For example, we have hundreds of monkeys, of known pedigree, interacting with each other in a purely spontaneous and naturalistic fashion. You can’t get that in a lab.”

Lauren Brent conducting behavioral observations on Cayo. Courtesy of Lauren Brent.

Lauren Brent conducting behavioral observations on Cayo. Courtesy of Lauren Brent.

Although working with free-ranging monkeys can produce more naturalistic results, Brent noted that there are drawbacks to working in the field.

“Working with monkeys in the field is painstaking,” Brent said. “You need to be physically fit, but moreover it is a mentally demanding thing to do because you need to pay close attention to everything that is going on in the group at all times so that the data are as finely detailed and accurate as possible.”

Brent found that a monkey’s position in its social network is heritable and can impact the survival of its infants. She determined a monkey’s social connections using grooming and spatial proximity, or how long one monkey spends sitting next to other monkeys.

“Regardless of how big your family is, monkeys who are better connected in the grooming network have greater reproductive success,” Brent said. “Together, these results suggest that social interactions have adaptive benefits and are something on which selection has acted.”

Mining Appalachia has permanent effects on its landscape

A satellite comparison of the Hobet-21 Mine in 1987 and 2002 (Courtesy of NASA).

A satellite comparison of the Hobet-21 Mine in 1987 (below) and 2002 (Courtesy of NASA).

By Ashley Mooney

While mining the Appalachian mountains provides fuel to many areas of the East coast, Mariah Arnold, Fulbright scholar and Duke doctoral candidate, found that current mining practices may release toxic substances that devastate local ecosystems.

Arnold said about 450 mountains across the country have been destroyed by mountaintop mining. She focuses her research on the Hobet-21 mine in southeastern West Virginia—the largest surface mine in the state.

“The problem with mountaintop mining is that the impacts are so long term,” said Richard Di Giulio, professor of environmental toxicology and Arnold’s advisor. “We’ve blown away mountains and they will never come back.”

Most mountaintop mining in West Virginia occurs in remote, sparsely populated areas, Di Giulio said. Although one can drive relatively close to the sites themselves, the true effects are hard to see from the ground.

During mountaintop mining, miners extract coal by removing the land above the coal seams, then use a process called valley filling to repurpose the excess land, Arnold said. The process releases selenium, a sometimes toxic naturally occurring element found in the earth.

Untitled

Arnold and Research Analyst Ty Lindberg collecting samples in the Mud River. Courtesy of Mariah Arnold and Ty Lindberg.

“Selenium is released into the environment when you blast off that mountain and you have all that excess rock, which has been in that mountain for a very long time,” Arnold said. “When you expose it to the air and rain and weathering events, that rock is broken down, and in that rock is selenium. Selenium is then washed down into aquatic habitats.”

Not all forms of selenium are toxic, and some are actually required in human diets to survive. According to the U.S. Environmental Protection Agency website, there is a limit on “the highest concentration of [selenium] in surface water to which an aquatic community can be exposed indefinitely without resulting in an unacceptable effect.”

Arnold found that samples taken from the Mud River, which flows through the mining site, contain significantly more selenium than the legal limit. The excess selenium has killed off several fish species and caused reproductive failure and jaw deformities in the remaining fish, she said. Species from a fork of the river that does not flow through the mining site do not exhibit the same problems.

A key to Arnold’s findings is biofilm, which refers to a group of microorganisms that stick to each other on surfaces in the river. The biofilm in the Mud River converts the selenium released from mining from an inorganic, harmless form to a dangerous organic form of the compound. Some animals, including fish and insects, eat the biofilm and therefore ingest the now-harmful substance.

“A third of [the selenium in the river] was in green algae,” Arnold said. “The first thing these fish eat is that green algae, so that’s really the dose the fish are getting…. These biofilms are controlling the movement of selenium.”

The long-term impact of selenium exposure in many species, including humans, is still unknown, said Di Giulio. Future studies will include selenium’s effect on human health and further understanding the role of biofilm.

While some species can evolve and adapt to the rising selenium concentrations, Di Giulio said the mountains themselves could never recover, because they require hundreds of years to adapt to the changing ecology.

“You have forever essentially destroyed this landscape,” Di Giulio said. “You go there, its like, ‘oh we need flat space here for shopping centers and hospitals and schools,’ but yet the population density really is [low]. Do you need this much?”

The Congolese Jane Goodall

By Ashley Mooney

The bonobos have found their Jane Goodall, and this time she’s from the Congo.

Photo by Ashley Mooney.

Suzy Kwetuenda visiting Duke. Photo by Ashley Mooney.

Although bonobos are native to the Congo, Suzy Kwetuenda is the first Congolese person to study them. Kwetuenda is a Congolese scientist who runs bonobo care and conservation programs at the Lola ya Bonobo sanctuary in the Democratic Republic of Congo. The sanctuary provides rehabilitation and protection for young bonobos who are orphaned by the bushmeat trade.

She was at Duke this semester to work with members of the Brian Hare Lab, with whom she has worked for about 10 years. She also coordinates field research for the Duke students and faculty who study bonobos at Lola ya Bonobo, said Postdoctoral Associate Jingzhi Tan.

“My role is first to learn more about [bonobos]. After that is about my country,” Kwetuenda said. “I want to help bonobos [become] a symbol of my country, just like you can see pandas from China.”The greatest threats to the endangered apes are the bushmeat trade and habitat destruction. Kwetuenda noted that in order to save bonobos, one must first take care of the people who live near them.

“They are still looking for bushmeat, because they are poor and the only big resource is the forest,” she said. “They go in to find any animal they can find, they don’t care about how it is or the population, because they are poor and they need to survive.”

Kwetuenda added that teaching people about bonobos and alternative food sources will help them be more cooperative with conserving bonobos and their habitats.

Courtesy of Jingzhi Tan, taken at Lola ya Bonobo Sanctuary.

Courtesy of Jingzhi Tan, taken at Lola ya Bonobo Sanctuary.

“My concern is really to let people—especially Congolese people—be aware that this is the closest [related] ape to humans and is really endangered,” she said. “They are only found in the forest at the center of Congo, and if nobody takes care of them, they will disappear forever.”

Since she is from the Democratic Republic of Congo, Kwetuenda believes that her voice will have more power in her country than if a non-Congolese person were attempting to save the bonobos.

“I think as a Congolese woman, it’s much easier to have trust of other Congolese. Because we’re still from the same origin, same root,” she said. “So I think it’s much easier that they can be aware that it’s a local concern and isn’t coming from somewhere else. “

What is a bonobo?

Bonobos are sometimes called pygmy chimpanzees, due to their strong physical similarities to chimpanzees but smaller size. But the small apes are not to be confused with the larger cousins.

Kwetuenda noted that bonobos have darker faces and longer hair “that will cover their small ears,” compared to chimps who have white faces and pink, visible ears. Bonobos also have webbing between their second and third fingers.

Beyond the physical differences, bonobos are much less aggressive than chimpanzees.

“The model they have for life [is] peace and no war,” Kwetuenda said. “So they make a lot of sex to solve any problem, any stress, any dispute. That’s why they are so kind and so social with each other.”

Back to the wild

Courtesy of Jingzhi Tan, taken at Lola ya Bonobo Sanctuary.

Courtesy of Jingzhi Tan, taken at Lola ya Bonobo Sanctuary.

Since 2009, Lola ya Bonobo has reintroduced dozens of bonobos to the wild. The bonobos who were released were picked because of their immunity and independence, Kwetuenda said.

“They are like humans, there are some who are weak and [get sick easily]. The first thing is who has more immunity and will survive the longest,” she said. “The second thing is… who is able to take care of themselves?”

Before bonobos are released, Kwetuenda noted that she wants to be sure that they will not try to return to humans.

“Most of them are orphans, so they really need to trust each other,” she said.

Some of the released bonobos had lived in captivity for up to 10 years, and Kwetuenda noted that how they will adapt to the wild is one of her biggest concerns. One bonobo, however, has stepped up to help newly released ones readapt to the wild.

“We had one teenager in the first group who was like a substitute mother, she was like the angel of the group,” Kwetuenda said. “She was taking care of the new ones, trying to give them food, and teaching them how to look for food on their own.”

Courtesy of Jingzhi Tan, taken at Lola ya Bonobo Sanctuary.

Courtesy of Jingzhi Tan, taken at Lola ya Bonobo Sanctuary.

Kwetuenda described this bonobo’s actions as empathy. When the bonobo first arrived in the forest, it was often lost and got into trouble. She said she believes the bonobo used its own experiences with reintroduction to help the others.

“She understood how it was tough to be wild,” Kwetuenda said.

Saving bonobos

She noted that while Congo and the bonobos seem far away, Duke students can help by joining the research effort.

“We just need to have more studies and try to let people understand how amazing bonobos are, how clever bonobos are,” she said. “Bonobos have different personalities. There are some who are shy, you have kind ones [and] you have bad ones. “

Collaborating with American or European researchers, she added, can also help increase the credibility of her research. This collaboration provides the sanctuary with resources and access to labs, which would be very difficult to get otherwise.  There is currently a large war in another area in the Democratic Republic of the Congo, and Kwetuenda said authorizes are mostly interested political problems, not saving bonobos.

“Even though the economy in the world is very tough, we need to help them. We need to find money… to help the orphans,” she said.

Humans, Whales and Taylor Swift

by Ashley Mooney

The similarities between chromium workers and whales are greater than one might think.

Environmental toxicology researcher John Wise has been studying the connection between exposure to pollutants and the onset of cancer in humans. To understand the link, he said one must take into account all species, especially whales. Wise spoke at Duke Oct. 25 at the Inaugural Duke Distinguished Lecture in Cancer and the Environment.

800px-Chromium_crystals_and_1cm3_cube

Chromium crystals. Courtesy of Wikimedia Commons.

“For environmental health for me, [the Earth] is the big picture,” Wise said. “This is home and we only have one, so we have to think pretty hard about environmental health.”

Wise studies the effect of pollutants—specifically forms of chromium—on genetic material in humans, marine mammals, and birds and other marine species.  While the standard approach to environmental toxicology research is to conduct epidemiology studies on highly exposed populations and then expose animals to high doses of the toxin, Wise has adopted a new method of study.

“We don’t really know what high-dose exposures mean on a day-to-day basis,” he said.

To understand the relationship between chromium exposure and the onset of cancer, Wise looks at the personal factors that affect one’s health, such as an individual’s body and genome, lifestyle, daily exposures and what kind of environment one lives in.

“We need to know mechanism: how does a normal cell become a tumor cell?” he said. “For a long time that is where the field has been hung up, trying to identify the ultimate carcinogen.”

Most forms of naturally occurring chromium are not toxic. Man-made hexavalent chromium, however, has been shown to cause lung cancer in those who are regularly or heavily exposed to it. Prolonged exposure induces an altered chromosome number and structure, as well as DNA double strand breaks.

Chronic exposure to chromium also causes a shift from more a protective form of DNA repair called homologous recombination to a less stable and error-prone pathway called non-homologous end joining. This means that cells will have permanently deficient repair mechanisms.

Wise applies his research in the context of ocean health, namely how chromium exposure might harm whale DNA.

Most ocean pollutants, including the toxic form of chromium, are in the ocean sediment. As the ocean becomes increasingly more acidic, the sediment breaks off and poses a growing threat to marine species.

Wise measured chromium levels in baleen whale skin, and found that Atlantic seaboard species—the northern right whale, fin whale and humpback whale—have 16- to 41-fold higher levels than other baleen whales.  Toothed whales living in the Gulf of Mexico exhibited levels that resembled those found in chromium workers who died of lung cancer.

A humpback whale surfacing for air. Courtesy of: Protected Resouces Division, Southwest Fisheries Science Center, La Jolla, California. swfsc.nmfs.noaa.gov/PRD/.

A humpback whale surfacing for air. Courtesy of: Protected Resouces Division, Southwest Fisheries Science Center, La Jolla, California. swfsc.nmfs.noaa.gov/PRD/.

In whales, chromium can lead to DNA damage and reproductive suppression.

“There’s only 400 [northern right whales] left in existence,” Wise said. “If you only have 400 animals, you need every single one of them [to be able to reproduce].”

Wise said he hopes his research will encourage people to think more about habitat degradation and climate change, and how they affect all species.

taylor-conor-sailing-team, courtesy of popdust.com

Wise (back right) photographed with his lab and Conor Kennedy (back left). Courtesy of popdust.com.

His lab, however, has recently gained publicity not for its research, but for the public figures that have worked with it. Conor Kennedy, a member of the influential Kennedy family, worked with Wise’s team and Ocean Alliance last year. At the time he was dating pop-star Taylor Swift.

“[He was], like any other high school student, constantly texting on his phone and I would do what I did with my kids and the other students, and say ‘put the girl down, we have to go to work,’ not knowing the girl was Taylor Swift,” Wise said. “It really hit home that we were traveling in very different circles.”

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