Sunday, February 28, 2010

Don’t join a Frat – You could Die!

Your average binge-drinking frat guy may be too busy funneling beer to chain smoke. A nonsmoker student riding in a car with a “heavy smoker” may be at greater health risk than a “puffer” who smokes once every few days.

A study done at Wake Forest in December separated a previously homogenous group of college smokers into five subgroups, and the study’s results can be used to see which and when college students are at greatest health risk.

Previously, whether a college student smoked one or 300 cigarettes in the past 30 days, he or she was labeled a college smoker. However, recent nicotine and tobacco research done by Mark Wolfson at Wake Forest has removed this façade of homogeneity.

A survey done of 1,102 past-month smokers from 10 North Carolina colleges identified five heterogeneous groups of college smokers. Participants completed a Life-Cycle Assessment developed by the EPA and were divided into homogenous groups with similar smoking patterns including: “smoking behavior, including quantity and frequency of smoking, smoking contexts, and weekly patterns of smoking.”

The subclasses included "heavy smokers", “moderate smokers”, “social smokers”, “puffers”, and “no-context smokers.”

Because of the lack of homogeneity in previous college smoking studies, which used the previous definition of “college smokers”, new insight is found on what and when groups of college students are at the greatest health risk.

“Puffers” made up 26% of the North Carolina college smokers sample. Underclassmen were more likely to be “puffers” than were upperclassmen. This study reflects the addictive nature of cigarettes, “puffers” turning into “moderate smokers” and “heavy smokers” as time passes. This study shows that as students progress through college, the amount they smoke also increases.

Surprisingly, Greek members are more likely to be “puffers” and “social smokers” (19% of NC college smokers sample) than “moderate smokers” (22%) or “heavy smokers” (28%).

Further, “puffers” and “social smokers”, which were more likely to be involved in Greek organizations than any other subclass, are also more likely to be current drinkers or binge drinkers than were “heavy smokers”.

The study surprisingly found evidence against the cliché of Greek members binging on every drug available. Although Greek members are smoking less than the average college student, they are binge drinking far more.

Wolfson’s study only covered smokers, just half of the concern of state officials. Universities across the state have been trying to eliminate sources of second-hand smoke for years.

For example, the University of North Carolina incorporated a campus-wide smoking ban. At North Carolina State University, students were banned from smoking too close to campus buildings. To determine the primary sources of secondhand smoke, Wolfson conducted further research.

Wolfson surveyed 4,223 students (smokers and non-smokers) at 10 universities in North Carolina about their exposure to secondhand smoke. Eighty-three percent of students reported exposure in the seven days prior to the survey. With studies showing links between secondhand smoke and morbidity from heart disease, lung cancer, etc., discovering where students are being exposed provided insight on how to cut down on secondhand smoke health risks.

Sixty-five percent of college students surveyed were exposed to second-hand smoke in bars and restaurants. This puts upperclassmen at greatest risk, who are able to enter the 21-and-up bars as well as have enough money for $7 cocktails. However, North Carolina’s recent smoking ban in restaurants and bars will eliminate this source of exposure unless a person is unlucky enough to walk through the cloud of smoke effacing the entrance.

Fifty-five percent of students were exposed to secondhand smoke from being in the same room as a smoker at college students’ homes. Only 38% were exposed to secondhand smoke from being in the car with a smoker.

Although Greek members are not the heaviest smokers, the vast amounts of people at Greek events, and results showing an increase of smoking amount while binge drinking, caused an increased risk of secondhand-smoke exposure.

Wolfson’s studies split a previously homogenous group into five smaller homogenous groups to better determine when college students are at greatest risk, as well as which students are at greatest risk of secondhand-smoke exposure.

For the anti-Greek like me, we finally have a study showing that you should not join a fraternity or sorority if you do not wish to increase your risk of become a binge drinker, become a casual smoker, or increase exposure to cancer-causing secondhand-smoke at every oh-so-fun Greek event.

Friday, February 26, 2010

Old Standards Threaten Infant Life

The way that newborns are cared for in hospitals may see drastic revision after a startling study by the Duke University and the University of North Carolina’s Schools of Nursing shows that abdominal temperatures considered “normal” may be fatal to many infants. Neonates, in the first hours of life, often cannot regulate their body temperatures on their own and require external heating from nursing heaters called “servos”. The study concludes that “the traditional cut point of hypothermia (97.5 °F) may not be enough to minimize abnormalities in heart rate” and that because of this, there should be widespread reform to have nurses raise infant servo temperatures from the dangerously low 97.5 °F to between 98.24 °F and 98.42 °F. What may seem as a small difference in temperature (1.8 °F or 1°C) is the difference between life and death for preemies.

The study’s main focus was on the first 12 hours of life of extremely low birth weight infants (ELBW) in the Neonatal Intensive Care Unit (NICU). These infants weigh between 14.1 and 35.3 ounces, or from 0.88 to 2.21 pounds, and have dangerously thin skin making them susceptible to heat loss. ELBW infants are usually only 28 to 29 weeks gestational age. Prior research has established that hypothermia during the first 12 hours is especially harmful to premature infants and can lead to increased mortality and morbidity. A study by Deussen in 2007 reported that “Once the body temperature falls below 93.4 °F, cardiac output reduces due to bradycardia” (a heart rate under 100 bpm). Infants are unable to self-regulate body temperature until around week 32 gestational age. According to National Vital Statistics reports, there were roughly 33,000 ELBW infants born in 2003, which was about 0.8% of the total children born that year (Matthews and MacDorman).

Approximately 66% to 93% of ELBW infants are admitted to the NICU with hypothermic temperatures. Additionally, ELBW deaths accounted for almost 49% of all infant deaths in 2003. The U.S. Census Bureau found in 2006 that approximately 4.3 million babies were born in the U.S. According to a study by Dr. Bennett of the University of Washington School of Medicine, “Of the approximately 4 million annual live births in the United States, 7.5% are classified as low birth weight (LBW, < 5.51 lbs)

Reforms in nursing practice have been suggested by Dr. Knobel et al. and include the raising of incubator (servo) temperatures, using polyethylene bags for heat insulation, and the pre-heating of intravenous fluids, bedding, and delivery rooms. Anything that an infant may come into contact with during these critical first 12 hours must be warmed, even the air. Only 20% of 125 NICUs surveyed by Knobel in 2005 adhered to the American Academy of Pediatrics and American Heart Association recommendation to use polyethylene bags for heat loss prevention during delivery room resuscitation.

Admitted limitations of the study include a small sample size (10 ELBW infants) and an insufficient demographic. Reforms must be enacted quickly to help protect the 33,000 ELBW infants born each year.

By: Jim Allen

Original articles:

"Optimal Body Temperature in Transitional Extremely Low Birth Weight Infants Using Heart Rate and Temperature as Indicators." Journal of Obstetric Gynecologic and Neonatal Nursing 39.1 (2010): 3-14.

"Thermoregulation and Heat Loss Prevention After Birth and During Neonatal Intensive-Care Unit Stabilization of Extremely Low-Birthweight Infants." Journal of Obstetric, Gynecologic, & Neonatal Nursing 36.3 (2007): 280-287.

"Hyperthermia and hypothermia. Effects on the cardiovascular system." Anaesthesist, 56, 907-911.
Infant mortality statistics from the 2003 period linked birth/infant death dataset. National Vital Statistics Reports, 54, 1-30.   

Songbird Study May Help Vocal Learning

Birds burst into song as you step into the room. Behind you, the door closes with a small metallic click and the birds’ song fades as the buzzing of electric lights and machinery begin to overpower it. Despite the white noise, you notice that one bird sounds different from the others. This bird is one of the test subjects in research conducted by scientists at Duke University Medical Center who are trying to discover how a songbird’s brain functions when learning a song.

The study, published online in Neuron on January 13, 2010, is the first to identify an auditory feedback pathway in the brain that controls vocal learning. This research lays the foundation for improving human speech in people whose auditory nerves are damaged and who must learn to speak without the benefit of hearing their own voices.

At this stage, using humans in experiments is impossible, but these songbirds are working well as substitutes. Amazingly, the brains of songbirds and humans function similarly during the process of vocal learning. Richard Mooney, PhD, Duke professor of neurobiology and senior author of the study, said, “The problems that juvenile birds solve when they learn a song from a tutor bird are similar to the problems humans solve when we learn to speak, and birds and humans exploit similar neural systems to reach this solution.”

The team sought answers to how the brain programs and channels auditory feedback to shape the vocal performance in juvenile birds that are learning to sing.

Initially, the scientists identified the neurons in the songbird brain that convey the auditory feedback needed to learn songs. Then they passed a brief pulse of electricity through the implanted electrodes to alter the brain’s activity associated with one of the notes that the pupil was learning to sing.

Three interesting dynamics emerged. First, the distortion in the bird's singing was delayed and showed up anywhere from hours to weeks after the bird first heard the electrical noise pulse in its song. Second, the distortion always came in the same place in the bird’s song, at the exact point in the song where the electrical "noise" was introduced. Third, by disrupting neural activity at different stages of the learning process, they determined that the distortion effects were strongly age-dependent. Younger birds sometimes showed changes within an hour while older birds kept singing properly for a while but eventually changed over a period of weeks.

Mapping the brain pathways for this auditory feedback might eventually make it possible to find a way to stimulate those pathways in humans. Speaking intelligibly when you cannot hear is not an easy task and one which can only be accomplished after years of exhausting training. If an easier way is found, it could help to facilitate communication between people who can and cannot hear.

Essence of Zebrafish

Since the 1970’s, the curiously cute and scientifically essential Zebrafish has been used in various studies as an experimental representative for all vertebrates. Though this fluorescent, black-striped fish has no obvious superficial qualities characteristic of humans, it still offers scientists a unique view into human embryo development as well as offering vital information regarding the growth of cancer cells. A study published in the Journal of Biological Chemistry by North Carolina State University (NCSU) researchers discusses and explains these newly found insights.

The protein Sp2 is a kind of gene on-off switch that controls cellular growth. These NCSU researchers had the hypothesis that the over-production of this protein could be used as an indication of the formation of a tumor. Considering the Sp2 protein found in Zebrafish is identical to that found in mammals, its purpose can be directly related to the same Sp2 protein found in humans. First, a fluorescent marker was attached to the Sp2 proteins found inside Zebrafish. When these fish were exposed to ultraviolet light, their Sp2 proteins glowed bright red, allowing scientists to track exactly where Sp2 was active inside the Zebrafish. For example: an adult, egg-carrying Zebrafish had a bright red glow located only in her ovaries when exposed to this ultraviolet light. After this female laid her eggs, it was apparent that the red glow was also seen within the eggs themselves, suggesting not only the transfer of Sp2 from parent to possible child, but that the Sp2 protein is vital to the earliest stages of embryonic development. It was also observed that when eliminating this protein within an embryo, the embryo ceased to develop. This is big news considering how delicate, complicated and significant the development of an embryo is to the lifespan and health of all vertebrates.

Associate professor of oncology at NCSU, Dr. Jonathan Horowitz, believes that not only is this ongoing research telling of the development of an embryo, but that it may play a big role in answering specific cancer related questions. These questions include more than just if a tumor is forming but what type of tumor it is. Making these possible findings even more tantalizing is that this could all be figured out within the earliest stages tumor development. Subsequently, it is to be noted using Sp2 as a marker to catch tumor development is an educated hypothesis of Dr. Horowitz and his team, not an actual finding. Since cancer plays a very prominent role in the life and death of organisms, this study is possibly a small but important step forward in cancer research. According the Centers for Disease Control, cancer is second only to heart disease in deaths in America. This would account for over 20% of the population.

“We think that these fish may be a useful tool – an aquatic canary in the coal mine – that will allow us to detect early tumor development." - Horowitz

The Oldest Eco-tech: Trees

We need a machine that can clean pollution out of the ground and the water table. It has to suck the bad stuff (pollutants) out and leave the good stuff (water and dirt) in. Then, somehow, the machine needs to break the poisonous molecules into smaller, harmless ones, thus recycling pollutants without producing any additional waste in the process. One imagines a tangle of tiny tubes linked to sensors, vials, and off-gas valves—an ecological engineer’s lifework, perhaps.

But environmental scientist Elizabeth Nichols and her graduate student Rachel Cook think the fantastic machine already exists: it’s a tree.

The state of North Carolina approached Nichols with the same problem in the mid-90’s. A World War II Air Force depot near Elizabeth City had been dismantled. The work uncovered concrete bunkers under the tarmac, and the bunkers were slowly seeping their contents—150,000 gallons of jet, diesel, and gasoline airplane fuel—into the surrounding soil. The fuel occupied the first level of water table, a mere 7 feet beneath the soil.

And the tarmac was about 100 meters from the Pasquotank River.

“The question was first how to slow the seepage down, then ultimately how to draw the pollutants off the water table. And how to do it without disturbing the surrounding ecology even more,” Nichols said.

Her answer was phytoremediation—an application that uses plants as well-designed eco-tech. Nichols and her collaborators (USGS, NCDENR, and US Coast Guard) planted poplar, willow, and pine trees to slow groundwater seepage, slowly draw the diluted fuel from the groundwater, and then release the broken-down fuel, in the form of hydrogen and oxygen, into the air.

“Jet fuel isn’t good for trees,” Nichols said, “and you can see bare spots where the soil is saturated.” But trees like the willow pull water off the top of the water table, where lighter jet fuel floats. Nichols and Cooks’ results imply that the trees have had significant impact on pollutant levels since 2006.

Phytoremediation as a major means of ecological remediation hasn’t been widely accepted, yet. This study serves as a demonstration site for North Carolina-- consideration of a holistic and far-seeing approach to an immediate threat to resources. Nichols and Cook want to prove that such foresight can be successful.

The study is funded by the EPA and North Carolina’s Department of Natural Resources’ 319 program to clean surface water. Cook’s paper describing the current state of groundwater at Elizabeth City site will be published in the next issue of the International Journal of Phytoremediation, due out later this year.

Using Effluent Water for Landscaping - Is it Safe?

Sarah Davis climbs into a small metal fishing boat at the edge of a one-acre pond near Wilmington, North Carolina. She paddles the boat until the swirling mud is too deep to see and then grabs a small capped vial from her pocket. An N.C. State graduate student in the department of crop science, Davis wants to know if this pond of effluent water—wastewater pumped from the city’s sewage treatment plant—is killing the turf on the golf course surrounding it.

Findings from her research, led by plant physiologist Danesha Seth Carley and published in 2009 in International Turfgrass Society Research Journal, show that the treated water may harm the grass. Those findings also show that what Carley feared the most—salt toxicity—was not a problem. However, nutrients from the effluent water may have an unwelcome effect: attracting pests.

Effluent, or treated water, has traditionally been piped from the sewage treatment plant directly into nearby lakes and streams. To limit the amount being added to freshwater systems, some municipalities are finding other uses for it, such as irrigation.

“When done properly, effluent water is perfect for irrigation,” says Carley, a specialist in turfgrass physiology. “The grass filters the water and keeps excess nutrients from winding up in lakes and streams.”

Because the arid climate and populated cities strain drinking water supplies, municipalities in several western U.S. states have transitioned to landscaping with effluent water. However, scientists in Arizona have found that the water increases the salt content of the soil, creating the potential to kill the turf. Without living plants to absorb the water and filter excess nutrients, water pools on the ground, creating runoff and erosion problems.

So when several North Carolina communities began requiring golf course superintendents to irrigate their turfgrass with effluent water, Carley and a team of plant physiologists and soil scientists from N.C. State University decided to take a closer look at the chemical makeup of the water.

In her lab in the crop science department, Carley takes the liquid contents of the tubes that Davis has brought her and analyzes them with a carbon/nitrogen analyzer. The machine consists of a computer that looks like it’s been salvaged from the 1990s, hooked up to a series of tubes and vials. N.C. State researchers have collected samples from numerous wastewater retention ponds over an 18-month period, from January 2006 to May 2007.

Rows of numbers appear on the monitor screen. The machine has returned data results for sodium, phosphorus, sulfur, nitrogen, magnesium, calcium and carbon. The data give Carley good news—the salinity of the water is at levels tolerable for turfgrass. Only in severe drought would the salt content of the water cause salt toxicity to the turf roots.

However, the high nutrient content, combined with the salts, create a friendlier environment for bacteria and other pests to grow.

“Nutrients increase fungi, bacteria and insect populations in the soil,” Carley says. Some of those insects attract other pests, such as skunks, an unwelcome addition to both the home landscape and the golf course.

Does use of effluent water ultimately mean more skunks in the landscape? Not if soil nutrients are balanced, says Carley. A soil test will indicate how much—if any—fertilizer is necessary.

Duckweed: The All-In-One Environment Saver?

If you have ever been driving with your windows down on a summer afternoon and smelled a paper mill, fresh cow pasture, or rotting fragment of road-kill, then you can surely appreciate the situation for the people living near swine farms in eastern North Carolina. The smell of swine feces, an infinitely worse stench than you can imagine, has the known ability to permeate not only the surrounding air for miles, but a person’s clothes, hair, house, and food.

Researchers at North Carolina State University (NCSU), specifically Dr. Anne-Marie Stomp in the department of forestry, Dr. Jay Cheng in the department of biological and agricultural engineering, and Dr. Mike Yablonski, a post-doctoral researcher, are stepping in to meet the challenge of the odiferous lagoons and are posing solutions to even more pressing problems in the process.

Finding the solution to the stinky lagoon problem, past researchers looked in the most unlikely of places…in an unattractive, tangled mass of root and leaf-like structures collectively known as “duckweed”. While past researchers studied duckweed for applications ranging from consumption to very recently ethanol production, the researchers at NCSU are the first to bridge the gap between thought and actually making ethanol production from duckweed viable. Before the method on how to make ethanol is described, it is important to see if duckweed can handle the differences found in the various lagoons across NC.

Stomp and Cheng, in their paper written in the year 2000 for the initial problem of nutrient removal from swine lagoons, partly focused on finding the combination of duckweed species (three species were chosen to experiment with from past work) and lagoon effluent concentration that maximized the ability to produce duckweed biomass, the primary precursor to ethanol. In order to find the best lagoon effluent concentration to generate biomass and best variety of duckweed to handle a desired concentration, the researchers allowed the three varieties of duckweed to grow on varying effluent concentrations (20, 25, 33, 50, and 67%) for 12 days in greenhouse conditions simulating typical summer weather. The testing conditions were special to this study because the effluent was taken from the NC State University Field Laboratory and could not represent all of the varying types of swine effluent in eastern NC, but the conclusions of the study prove a very important point.

After sampling the duckweeds intermittently for 12 days and measuring the wet weight, dry weight, and percent dry weight, the researchers were able to determine a trend and prove that any swine lagoon could be optimized for either duckweed biomass production or cleaning of the swine wastewater. The researchers even venture to say that the lagoons (and duckweed species) should be optimized before biomass production is ever attempted.

Due to these findings about ten years ago, the researchers continued the work and studied how duckweed grew in swine feces and ways in which they could convert it to ethanol. The culmination of their work will come to fruition with the completion of a pilot plant for harvesting aimed at the steady production of duckweed, which will provide the biomass necessary for ethanol conversion. The process the researchers will use to convert the biomass to ethanol mimics the same process for converting corn biomass to ethanol, of which the process is very well understood. The ultimate deciding factor, though, will remain in the economic analysis, of which the researchers are completing at this point in time.

While at first glance appearing to be an ugly aquatic weed, duckweed has given hope to a remedy for the stinky swine lagoon problem and a possible source of ethanol production. Maybe natures most exciting solutions to man-made problems do come in the smallest and most unnoticeable packages.

By Steven Burgess

Peer-reviewed research can be found at:

Bergmann, B. A. et al "Nutrient Removal from Swine Lagoon Effluent by Duckweed." American Society of Agricultural Engineers 43.2 (2000): 263-269. Print.

Cheng, Jay J., and Anne-M Stomp "Growing Duckweed to Recover Nutrients from Wastewaters and for Fuel Ethanol and Animal Feed." Clean Soil Air Water 37.1 (2009): 17-26. Print.

Thursday, February 25, 2010

Too Drunk to Fly

Shannon Maryman

Why would anyone pay to get fruit flies drunk? In the October 2009 issue of Genetics, North Carolina State University and Boston University joined together for a genome-wide association study to identify an enzyme that is associated with consuming alcohol. In this experiment, the effects of alcohol on fruit flies were evaluated and the results were translated to humans for applicability of study.

They identified seven intronic single nucleotide polymorphisms (SNPs) of the Malic Enzyme (MEN) 1 gene in fruit flies that altered under the influence of alcohol. A SNP represents a single building block to DNA for example cytosine (C) or adenine (A). Therefore, they discovered seven specific locations in the MEN that have an altered nucleotide from the norm. Since the SNPs are different, scientists can locate these specific nucleotide “markers” and see how they affect the gene’s function.

The graph to the left plots the MEN activity versus the standardized MET, the mean elution time, for all the fruit flies after the second exposure to alcohol. The MET, in other words, is the amount of time the fly resembled a drunken person until it passed out and could no longer fly. Therefore, the larger that value the MET is, the higher the tolerance the fruit fly has to alcohol. The fruit flies that displayed a higher tolerance also displayed a higher MEN activity. [1]

The MEN is a critical metabolic link of the glycolytic pathway to the tricarboxylic acid cycle by converting malate into pyruvate. If this enzyme activity increases with the increase in alcohol tolerance, the MEN would be creating an excess of pyruvate. Who cares what pyruvate is, it doesn’t affect me; Right? No, even without understanding what pyruvate is, an excess of anything in the body is not healthy. The body will convert excess material into fat to store “energy”. In this case, pyruvate can lead to fatty liver syndrome.

The isolation of this enzyme in humans altered in the same trend when intoxicated as seen in the fruit flies. Researchers have been able to find these “markers” in generations of families or civilizations and have linked the SNPs to diseases. In other words, you have a higher susceptibility to alcoholism, if family members are alcoholics.

The research done by these two universities has proven to be significant. Tolerance and sensitivity to alcohol can be defined and explained by the changes in theses seven nucleotides. The result confirms alcoholism as a disease and explains how it can be passed through generations of families. From this research, a drug company will be able to synthesize a drug that will reduce the MEN activity that is enhanced when intoxicated. This is the first leading step in analyzing alcoholism for humans. Will this new drug be able to “cure” alcoholism? We will have to wait and find out.

Reference: [1] Morozova, Tatiana V., Julien F. Ayroles, and Katherine W. Jordan. “Alcohol Sensitivity in Drosophila: Translational Potential of Systems Genetics.” Genetics. 183 (2009): 733-745.

Photo: M. Plonsky 2004