Tuesday, January 29, 2013

Catch a rising star of ichnology

A sea star makes a trail on a barrier island beach, from the book "Life Traces of the Georgia Coast" by Anthony Martin.

Emory ichnologist Tony Martin drew a standing-room-only crowd on Saturday for his Atlanta Science Tavern talk about tracks, burrows, trails, nests, tooth marks, feces and other signs left by plants and animals. Who wouldn't want to follow an expert on tracks?

Here’s an excerpt from a post Martin wrote about his work for the “Wonders and Marvels” blog:

“In reality, the majority of ichnologists ignore humans, and more often use their observations of modern non-human traces as guides for traveling back in time to interpret the products of behavior from earth history. This is how we can interpret when (and why) a trilobite stopped and changed its direction while burrowing along a Paleozoic seafloor more than 400 million years ago. This is how we figure out what a dinosaur was eating on a given day during the Mesozoic Era, and that dung beetles were living with those dinosaurs, making use of the digested part of that dinosaur’s meal. This is how we identify the size and species of fish that swam along a lake bottom more than 50 million years ago, despite it having left only marks from its fins and mouth. Given nearly 10 million species of modern life-forms and their behaviors to consider, four billion years of life history, and innumerable trace fossils that resulted from that life, why should we waste our time being anthropocentric, or otherwise let ourselves be distracted by just our species in the here and now?”

Martin will give another talk on February 5 at the Decatur Library, where he will also be signing copies of his new book, “Life Traces of the Georgia Coast.” And on February 24, Martin will be the guest lecturer at Andalusia, the Milledgeville farm of Flannery O’Connor.

Lake-bed trails tell ancient fish story
Polar dinosaur tracks open new trail to past
Burrow into a good book on wildlife traces
Insider's guide to Georgia barrier islands

Thursday, January 24, 2013

Canine brain-tumor treatment trials may help humans

Following a seizure, Petey the pit bull was diagnosed with a brain tumor. He is doing well after undergoing treatment in a pilot trial in 2011.

By Janet Christenbury
Woodruff Health Sciences Center

The American Kennel Club Canine Health Foundation, Inc., has awarded the University of Georgia (UGA) College of Veterinary Medicine and Emory University a $119,000 grant over three years to test a newly developed experimental drug to treat dogs with naturally-occurring brain tumors, following partial surgical removal of those tumors.

The goal of the research is to help translate new brain cancer therapies to humans by assessing results in dogs with similar diseases. According to the researchers, the tumors in dogs, known as spontaneous gliomas, are very similar to human malignant brain tumors both by imaging and biology, and both tend to grow back rapidly. The poor prognosis for dogs with gliomas is similar to human patients. The researchers are hoping the novel treatment being tested will slow down tumor growth.

A seven-year-old pit bull named Petey was the first dog enrolled in the initial pilot trial at UGA in 2011. Following discovery of a brain tumor after a seizure, Petey underwent surgery in September 2011 to remove a portion of the tumor. Simon Platt, a professor of veterinary neurology at UGA, performed the surgery and diagnosed Petey with a glioma. After surgery and for three days, an investigational drug was directly infused into the glioma tumor area via catheters, targeting any residual tumor cells. Petey underwent blood testing and complete neurologic testing confirming no toxicity of the therapeutic agent.

Six weeks after surgery, Petey had a follow-up MRI that revealed the therapeutic agent still within the remaining brain tumor. Petey had another MRI five months after surgery showing a marked reduction in tumor size. Petey is now seizure-free and doing well 15 months after surgery.

Read more.

Tuesday, January 22, 2013

Penicillin, not the pill, may have launched the sexual revolution

The 1950s were not as prudish as they seemed on the surface, says economist Andrew Francis. 

By Carol Clark

The rise in risky, non-traditional sexual relations that marked the swinging ‘60s actually began as much as a decade earlier, during the conformist ‘50s, suggests an analysis recently published by the Archives of Sexual Behavior.

“It’s a common assumption that the sexual revolution began with the permissive attitudes of the 1960s and the development of contraceptives like the birth control pill,” notes Emory University economist Andrew Francis, who conducted the analysis. “The evidence, however, strongly indicates that the widespread use of penicillin, leading to a rapid decline in syphilis during the 1950s, is what launched the modern sexual era.”

As penicillin drove down the cost of having risky sex, the population started having more of it, Francis says, comparing the phenomena to the economic law of demand: When the cost of a good falls, people buy more of the good.

“People don’t generally think of sexual behavior in economic terms,” he says, “but it’s important to do so because sexual behavior, just like other behaviors, responds to incentives.”

Syphilis reached its peak in the United States in 1939, when it killed 20,000 people. “It was the AIDS of the late 1930s and early 1940s,” Francis says. “Fear of catching syphilis and dying of it loomed large.”

Penicillin was discovered in 1928, but it was not put into clinical use until 1941. As World War II escalated, and sexually transmitted diseases threatened the troops overseas, penicillin was found to be an effective treatment against syphilis.

“The military wanted to rid the troops of STDs and all kinds of infections, so that they could keep fighting,” Francis says. “That really sped up the development of penicillin as an antibiotic.”

Right after the war, penicillin became a clinical staple for the general population as well. In the United States, syphilis went from a chronic, debilitating and potentially fatal disease to one that could be cured with a single dose of medicine.

From 1947 to 1957, the syphilis death rate fell by 75 percent and the syphilis incidence rate fell by 95 percent. “That’s a huge drop in syphilis. It’s essentially a collapse,” Francis says.

In order to test his theory that risky sex increased as the cost of syphilis dropped, Francis analyzed data from the 1930s through the 1970s from state and federal health agencies. Some of the data was only available on paper documents, but the Centers for Disease Control and Prevention (CDC) digitized it at the request of Francis.

For his study, Francis chose three measures of sexual behavior: The illegitimate birth ratio; the teen birth share; and the incidence of gonorrhea, a highly contagious sexually transmitted disease that tends to spread quickly.

“As soon as syphilis bottoms out, in the mid- to late-1950s, you start to see dramatic increases in all three measures of risky sexual behavior,” Francis says.

While many factors likely continued to fuel the sexual revolution during the 1960s and 1970s, Francis says the 1950s and the role of penicillin have been largely overlooked. “The 1950s are associated with prudish, more traditional sexual behaviors,” he notes. “That may have been true for many adults, but not necessarily for young adults. It’s important to recognize how reducing the fear of syphilis affected sexual behaviors.”

A few physicians sounded moralistic warnings during the 1950s about the potential for penicillin to affect behavior. Spanish physician Eduardo Martinez Alonso referenced Romans 6:23, and the notion that God uses diseases to punish people, when he wrote: “The wages of sin are now negligible. One can almost sin with impunity, since the sting of sinning has been removed.”

Such moralistic approaches, equating disease with sin, are counterproductive, Francis says, stressing that interventions need to focus on how individuals may respond to the cost of disease.

He found that the historical data of the syphilis epidemic parallels the contemporary AIDS epidemic. “Some studies have indicated that the development of highly active antiretroviral therapy for treating HIV may have caused some men who have sex with men to be less concerned about contracting and transmitting HIV, and more likely to engage in risky sexual behaviors,” Francis says.

“Policy makers need to take into consideration behavioral responses to changes in the cost of disease, and implement strategies that are holistic and longsighted,” he concludes. “To focus exclusively on the defeat of one disease can set the stage for the onset of another if preemptive measures are not taken.”

Images are vintage health messages from NIH National Library of Medicine.

Skeletons point to Columbus voyage for syphilis origins
Your brain, in love and in lust

Friday, January 18, 2013

For this chemist, science never gets old

"We are pretty close to having a final answer, but we don't have it yet," says John Codington of the quest to develop better ways to detect cancer.

By Mary Loftus

Having peppermint tea and crackers at a small table in the break room of Emory’s Whitehead Biomedical Research Building, John Codington looks out the window onto a crisp November day. The ninety-three-year-old chemist is wearing an orange sweater bright enough to eclipse the fall foliage. He has his own lab space just down the hall, where he comes nearly every day to work in cancer research.

The railroad tracks running by the Depot café are just visible through the trees. “That used to be a passenger stop when I went to school here,” he says. Codington’s journey has taken him full circle, from Atlanta, where his family moved when he was one, to college at Emory, to the University of Virginia’s malaria research program, to the National Institutes of Health, to Europe, to faculty positions at Cornell and Harvard, to private biotech companies, and back to Emory.

Cancer cells with antibodies.
His primary research concerns the chemical changes in cell surface glycoproteins associated with immunoresistance in tumor cells, and his goal is to develop a diagnostic assay of sera to detect the presence of a carcinoma (cancer found in epithelial tissues). He hopes to develop a better, more reliable, and consistent way to detect most cancers, preferably at the earliest stages. “The test must be robust and suitable for clinical use,” he says.

Codington’s lab isolated epiglycanin, and recognized that antibodies to epiglycanin signaled a cancer-specific substance in the blood of carcinoma patients. He has worked since to improve the diagnostic assay by making it more stable and consistent—a quest he plans to continue as long as he is able. “We isolated the active component of epiglycanin, which I call Emorin, for Emory,” says Codington, who admits to feeling more himself in a lab coat than street clothes. “We are pretty close to having the final answer but we don’t have it yet.”

Difficulties abound. Cancer, he says, is so close to being normal that many aspects of a cancer cell are present in normal cells. Also, when dealing with human serum, you are dealing with the entire history of each individual. “If they have had measles, or mumps, they have those antibodies. All of these things come to bear,” Codington says, “That’s why it’s taking so long, and why no one else has found it.”

Read more about Codington's work and life. 

Photo of John Codington by Kay Hinton.

Tuesday, January 15, 2013

How the dengue virus makes a home in the city

Like the housefly, the Aedes aegypti mosquito that spreads the dengue virus is a homebody, perfectly adapted to the domestic life of humans.

By Carol Clark

The mosquitoes that spread dengue fever tap into the domestic networks of humans, along with their bloodstreams, finds a study recently published in the Proceedings of the National Academy of Sciences (PNAS).

The data from Iquitos, Peru, shows that the trail of the most rapid transmission of human infections does not lead through large, public gathering places, as might be expected, but from house-to-house, as people visit nearby friends and relatives.

“It’s common in a dengue fever outbreak to first treat public places like schools for mosquitoes, but our results show the focus needs to be on residential networks,” says disease ecologist Gonzalo Vazquez-Prokopec.

Vazquez-Prokopec and Uriel Kitron, both from Emory University’s department of environmental studies, conducted the spatial-temporal analysis as co-authors of the study, led by Steve Stoddard and Thomas Scott from the University of California, Davis. The research is part of a major, ongoing dengue project that also includes scientists from the U.S. Navy; the University of Iowa; Tulane University; San Diego State; and researchers in Peru.

“On a global scale, human air travel is known as a driver of dengue virus circulation, but this is the first time we’ve quantified the powerful impact of human movement on the small scale of neighborhoods,” Vazquez-Prokopec says.

Substandard houses in Iquitos are havens for the mosquitoes that spread dengue.

The tropical disease is caused by a virus that is passed from the blood of one person to another through the bites of mosquitoes. Also known as “break-bone fever,” dengue causes debilitating pain leading to the hospitalization of many sufferers. Severe cases can be fatal.

“It is vicious, and rapidly growing as a threat,” Vazquez-Prokopec says.

During the last 50 years, the incidence of dengue has increased 30-fold and more than half the world’s population is now at risk. The World Health Organization estimates that 50-100 million dengue infections occur each year. That number is expected to rise as the climate warms and the trend toward urbanization continues.

During 2009 and 2010, dengue fever emerged for the first time in decades in the contiguous United States, when an outbreak in the Florida Keys led to 93 cases.

“There is no vaccine for dengue. The only way to control outbreaks is to kill the vectors – mosquitoes,” Vazquez-Prokopec says. Many of the places affected have poor public health infrastructure, he adds, so it’s critical to identify the most effective places to spray for the insects.

A 2009 outbreak of dengue in Iquitos killed at least 24 people and drove almost 1,000 sufferers to the hospital, where cots had to be set up in stairwells and hallways to handle the flood of patients.

The researchers tracked and mapped dengue outbreak patterns in two large neighborhoods, encompassing hundreds of homes in Iquitos.

A city of 400,000 located deep in the Amazonian rain forest, Iquitos is essentially an island, only accessible by boat or plane. The city has high unemployment, and the housing is often substandard. Water is stored in open containers in crowded homes that lack air-conditioning, or even window screens. These factors make the homes havens for Aedes aegypti mosquitoes, the primary vector for the dengue virus. These mosquitoes feast almost exclusively on human blood, bite during the day, and have a limited flight range of about 100 meters.

To study how the dengue virus spreads through Iquitos, the researchers tracked and mapped outbreak patterns of two large neighborhoods, encompassing hundreds of homes, over several years. When a case of dengue was confirmed through a blood test, social workers would interview the patient, recording all the places the patient went during the 15 days leading up to the onset of fever. Mosquitos were collected from as many of these locations as possible and tested to determine if they carried the virus.

The data from interviews of 2,000 people was plotted over time and space using geographic information systems (GIS) technology.

“People appear to be getting infected most often in homes, but not necessarily their own homes,” Vazquez-Prokopec says. “The main driver is people visiting friends and relatives in nearby homes.”

Interviews with dengue patients revealed that two-thirds of them had visited the same location.

“We suspect that the importance of human movement that we observed in Iquitos will hold in other populations and for other pathogens transmitted by the mosquitos that spread dengue,” Vazquez-Prokopec says. “The findings provide a different way for thinking about how a vector-borne pathogen may spread through a population, and have implications for better disease surveillance and control.”

Image credits: iStockphoto.com.

Disease trackers take aim at dengue fever
Dengue fever's growing range and virulence

Monday, January 14, 2013

Chimps play fair in the Ultimatum Game

From Woodruff Health Sciences Center

Chimpanzees have a sense of fairness that was previously seen as uniquely human, finds a study by Emory's Yerkes National Primate Research Center and Georgia State University. The researchers played the Ultimatum Game with the chimpanzees to determine how sensitive the animals are to the reward distribution between two individuals if both need to agree on the outcome.

The findings, published by the Proceedings of the National Academy of Sciences (PNAS), suggest a long evolutionary history of the human aversion to inequity, as well as a shared preference for fair outcomes by the common ancestor of humans and apes.

Click here to watch a video of the experiment.

“We used the Ultimatum Game because it is the gold standard to determine the human sense of fairness," says lead author Darby Proctor, a post-doctoral fellow at Yerkes. "In the game, one individual needs to propose a reward division to another individual and then have that individual accept the proposition before both can obtain the rewards. Humans typically offer generous portions, such as 50 percent of the reward, to their partners, and that’s exactly what we recorded in our study with chimpanzees.”

"Until our study," adds co-author Frans de Waal, "the behavioral economics community assumed the Ultimatum Game could not be played with animals, or that animals would choose only the most selfish option while playing. We've concluded that chimpanzees not only get very close to the human sense of fairness, but the animals may actually have exactly the same preferences as our own species."

For purposes of direct comparison, the study was also conducted separately with human children.

Capuchin economics: Monkeys on unequal pay
Sharing ideas about the concept of fairness

Friday, January 11, 2013

The pandas of our minds

Why do all those people keep staring at me?

We love “The Two-Way” post on NPR.org today, pondering the age-old question of why people find pandas so cute. “The Two-Way” reviews previous articles on the question, including a 2005 one by the Washington Post, and the findings of Emory psychologist Stephan Hamann that “cute” pictures cause increased activity in the brain’s middle orbital cortex:

“Some evidence,” the Post noted, “suggests the brain activity there is greater when the stimulus is ‘neotenous,’ which is to say it has juvenile characteristics – a button nose, big eyes, a large wobbly head, chubby extremities or pudgy cheeks.”

In other words, we’re programmed to be suckers for babies.

Read more on NPR.org.

Study gives clues to evolution of face recognition

Image: iStockphoto.com.

Monday, January 7, 2013

Burrow into a good book on wildlife traces

“It’s kind of a detective story,” Emory environmental studies professor Anthony Martin says of his latest book, “Life Traces of the Georgia Coast,” published by Indiana University Press.

Written for a general audience, the book describes how life traces – tracks, burrows and other impressions – relate to the natural history and behaviors of plants and animals of the beaches and maritime forests of Georgia’s barrier islands.

Ghost crabs and birds, feral hogs and alligators all leave signs of their activities in the environment. Many of these signs go unnoticed by most of us, simply because we don’t know how to read them.

“In many instances, you won’t see the animals that made these traces,” Martin says. “That’s one of the fantastic aspects of this book: You can use it as a manual for interpreting the natural world around you.”

Martin will give a public talk about the book on the evening of Saturday, January 26, for Atlanta Science Tavern. Click here for details.

Polar dinosaur tracks open new trail to past
Insider's guide to Georgia's barrier islands
Dinosaur burrows yield clues to climate change

Thursday, January 3, 2013

The art and science of symbiosis

"Art offers scientists a chance to see the systems they work on in a new light,” says Emory biologist Nicole Gerardo. Her lab studies evolution by observing interactions between microbes and other organisms such as aphids and fungus-growing ants.

Gerardo teamed up with Diane Kempler, a lecturer in visual arts, to teach a ceramics course called “Clay and Science: A Symbiotic Relationship.”

The students created pieces that explored everything from the interactions of lichen, bark and trees to the relationship between reading and the brain. You can see these works and others in the video above.

Prometheus: Seeding wonder and science
Tiny aphids hold big surprises in genome
Farming ants reveal evolution secrets