Australasian Science Magazine

By Stephen Luntz

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Alternatives Proposed for Anorexia Diagnosis
Gambling Interventions Questioned
Depression Monitored Online
It’s Hot Under Victoria
Viral Bypass Mechanism Revealed
“27 Club” Is a Myth
Exercise Fights Colorectal Cancer
Climate Change Species’ Final Straw
Australian Rice Has Promising Genes
Diversity Improves Ecosystem Function
Forests Emit 300% More Atmospheric Acid

Alternatives Proposed for Anorexia Diagnosis
Australian scientists are at the forefront of a proposal to change the way anorexia nervosa is diagnosed.

According to Prof Stephen Touyz of the University of Sydney, anorexia is one of the most serious psychiatric illnesses but is not treated as such. “In NSW there are almost no places for adults to get treatment without private health insurance,” he says. “There are two hospital beds at RPA, and another few at Westmead that aren’t specifically designated as eating disorder beds,” he says.

Moreover, it is particularly difficult to get patients to acknowledge their sickness. “If you have a sore tooth and the dentist says they can see you in 2 months you’ll say you can’t last that long,”Touyz says. “With anorexia it is the opposite. People who are sick resist treatment because that means putting on weight.

“People who have symptoms of anorexia nervosa but don’t meet the diagnostic criteria are currently described as having EDNOS, or ‘eating disorder not otherwise specified’,” Touyz says. Few people know what this is, making it easy for a teenager to fight worried parents’ desire for treatment.

This is tragic, because early treatment is effective. “If we get to treat someone within 3 years of developing anorexia there is a 60% chance they will fully recover,” Touyz says. “There is some evidence that the success is even higher in the first year.”

Later, however, prospects can be bleak. One in five patients with anorexia will die early through suicide, heart failure or other stresses placed on the body.

Touyz proposes the diagnosis of anorexia in four stages – similar to cancer or burns. While the public may not be aware of the technical criteria that determine each stage, they broadly understand what they mean. Someone diagnosed with stage 1 anorexia nervosa might find their condition harder to ignore.

Dr Sarah Maguire of Sydney’s Boden Institute of Obesity, Nutrition, Exercise and Eating has designed a computer program into which doctors can insert data for a patient to see whether it gives an anorexia diagnosis and, if so, at which stage it is. Touyz says comparisons with the clinicians’ judgments have shown promise.

Touyz, Maguire and others are lobbying for the four-stage diagnosis to be included when the American Psychiatric Association releases its new diagnosis guidelines in 2014. However, he expects that changes will be put on hold due to a lack of sufficient trials.

Gambling Interventions Questioned
A study of heavy gamblers in the ACT has revealed that few of those who experience significant ill-effects from gambling admit they have a problem, and fewer still seek help.

Less than 10% of people in the study who had some symptoms of gambling-related problems had accessed support services. The proportion rose among those who reported symptoms severe enough to meet mental health criteria, but only to 21%.

Dr Tanya Davidson of the Australian National University’s Centre for Gambling Research says the symptoms considered include “needing to gamble larger amounts of money to feel the same pleasure, chasing losses, selling things in order to be able to gamble, feeling guilty about the size of losses and financial problems”.

Most problem gamblers did so across a range of platforms, but the use of electronic gaming machines (EGMs) was most strongly associated with problems. Frequency of use and the size of losses were both significantly correlated with problem symptoms, which were most severe among those who lost more than $40 per week and used EGMs more than 100 times per year.

Davidson says she “won’t leap to conclusions” about any implications her work may have for the effectiveness of mandatory pre-commitment, and whether people locked out of EGMs will simply shift to other forms of gambling. However, she notes that those with a problem with poker machines are usually already using other gambling mechanisms, but without the same extent of troubles.

“Internet gambling is increasing, and there is evidence those gambling on the net have problems,” says Davidson, but they have usually gone through other forms of gambling first.

The study did not investigate what forms of intervention are effective, but Davidson notes that with most problem gamblers who don’t identify as such, the first priority is probably to get people to recognise that their gambling is interfering with their life.

Both the ACT and federal governments have expressed interest in the study and liaised with Davidson as to how it might be used to reduce gambling’s social impact.

Depression Monitored Online
A computer program has been released that enables patients with depression to track their mental health, assisting in the tailoring of treatments to each individual’s needs.

“Ultimately, we hope to assist patients with depression to monitor the progress of their illness in a similar way that a patient with diabetes monitors their blood sugar levels with a small portable device,” says Dr Roland Goecke of the University of Canberra.

“Psychologists and psychiatrists look for facial expressions, a lack of expression, longer response times and a reduced facial repertoire to identify depression,” Goecke says. “The goal is to develop a diagnostic aid using these.”

Towards this goal, patients are played a series of film clips designed to elicit both positive and negative responses. A computer program analysing the facial responses of 40 patients and 40 healthy controls has been able to diagnose depression with 80% accuracy.

Goecke says this can now be used as a sort of second opinion by a doctor, but the medium-term aim is for patients to only need to see doctors every 6 weeks, with the program providing monitoring in between.

“At the moment patients are asked to self-journal, which is hard to do if you are severely depressed,” Goecke notes.

The accuracy of the program may be improved if an individual patient’s status can be used as a benchmark. Patients are now being observed every 6 weeks and Goecke hopes this longitudinal data could eventually help to make the program more accurate. He also hopes to expand the markers used for diagnosis.

Depression is increasingly being recognised as a cluster of diseases, which complicates analysis. “At the moment we have looked at unipolar with and without melancholia, and bipolar, but with only 40 patients between the three categories we don’t have sufficient data to distinguish,” Goecke says.

It’s Hot Under Victoria
The geological equivalent of a CAT scan has been used to investigate the composition and temperature of the tectonic plate beneath south-eastern Australia. The findings may help to unravel the region’s geological past.

“However, until now it has been almost impossible for scientists to unravel the tectonic history of this fascinating part of the continent due to the presence of large, thin cover features such as the Murray-Darling Basin,” says Dr Nick Rawlinson of the Australian National University. “To get around, and below this, we used an Earth-imaging technique known as seismic tomography.”

Just as CAT scans illuminate the body with X-rays from multiple angles to construct an image of denser areas, seismic tomography detects earthquakes originating from distant parts of the world. Variations in the speed with which waves arrive can be used to determine the speed of vibrations through different parts of the subsurface.

However, Rawlinson notes that some care must be taken with interpretation. “Waves slow down through hot rocks, but also through certain types of material,” he says. But by combining the tomographic information with what is already known about an area’s volcanic history it is possible to draw conclusions about what is going on.

“In particular, there is a pronounced anomaly extending at least 150 km beneath western Victoria which points to elevated temperatures beneath an area known as the Newer Volcanics province,” Rawlinson says. “The region has experienced widespread eruptions until only recently, and it is likely that this ‘hot spot’ is responsible for those episodes.”

Competing theories suggest the heat may come from a mantle plume deep beneath the crust, or a local hot spot in the plate that does not penetrate very deeply. The two theories provide different predictions as to whether Victoria’s future volcanic eruption can be expected in Bass Strait or on land. Rawlinson says so far the distinctive signs of a mantle plume have not been detected, but this may be a result of lack of resolution below 50 km deep.

The 3D model constructed from the measurements also confirms expectations of stretching of the continent as Australia broke away from Antarctica. “It’s not a surprise,” Rawlinson says. “However, it is good to quantify how thin the plate has become for other studies. Even today there is no consensus on whether the southern highlands are an old chain that has been worn down, or are uplift associated with the formation of the Tasman Sea. This might help resolve that.”

Viral Bypass Mechanism Revealed
A bypass mechanism used by many viruses has been exposed, and inhibitors that may eventually form the basis for drugs against them have been developed.

HIV, hepatitis C, dengue fever and West Nile virus, among others, use enzymes in the human body to construct carbohydrates they need to grow. The primary pathway used to achieve this is well understood, and drugs have been produced that block this pathway. Nevertheless, the drugs have been unsuccessful at protecting against these diseases.

A/Prof Spencer Williams of the University of Melbourne’s Bio21 Institute says there are many theories about why these drugs have failed, but one is that they only succeed in blocking the primary pathway, allowing the viruses to use an alternative procedure that Williams has revealed in the Proceedings of the National Academy of Sciences.

“If we understand how the viruses use our enzymes, we can develop inhibitors that block the pathway they require, opening the door to drug developments,” Williams says.

“The body overbuilds carbohydrates,” Williams explains. “It constructs them out of building blocks of sugars, but it adds too many and then needs to delete some.”

In a process Williams makes sound like a student trimming back long essays one paragraph at a time, the body’s normal approach is to take out sugars individually. However, when this process is deleted the body can turn to more wholesale editing. Either approach can be hijacked by viruses.

The paper reveals the substrate the enzymes bind to allow the bypass mechanism to occur, as well as inhibitors that successfully compete with the substrate for access to the enzyme.

Williams acknowledges that a third pathway may exist, and says he plans to test for this by blocking both known pathways in cell cultures and seeing if the virus can still flourish. Even then he warns: “We’re a long way from putting a drug in a human and preventing disease.”

One obstacle to clinical applications is that any drug that shuts down both pathways would prevent the body from making the carbohydrates it needs itself. However, Williams notes that viruses replicate over periods of hours, and stopping them do so for a few days will usually clear the system entirely. “Just as a big tree can survive a drought while smaller ones will die, the body should survive the drug as long as it does not build up in the system.”

While there is a long way to go to produce medicines that can do this, an even bigger dream is to use the same technique to prevent cancer cells from creating the modified sugars that sit on their surface.

“27 Club” Is a Myth
The death of Amy Winehouse at 27 revived the idea of that age being particularly dangerous for musicians. However, the myth has been busted by rigorous statistical analysis published in the British Medical Journal.

A/Prof Adrian Barnett of Queensland University of Technology looked at the age of death of every musician, irrespective of nationality, who had a number one UK album between 1956 and 2007. All band members were included, even those whose identity was deliberately obscured. “We didn’t look at the Muppets themselves because they’re immortal,” Barnett explains. “However, we did look at the actors that played Kermit and Miss Piggy on their album.” Both are still alive, suggesting that fame as a frog or pig is not a health risk.

The lifespan of the 1046 musicians in the sample was compared with society at large. “During this period, 71 (7%) of the musicians died. We found no peak in the risk of death at 27,” Barnett says.

“However, musicians in their 20s and 30s were two to three times more likely to die prematurely than the general UK population.” Most of these deaths occurred in the 1970s and through the early 1980s, which Barnett proposes was caused by the partying music culture of the time.

“Interestingly, there were no deaths in this age group in the late 1980s, and we speculate that this could be due to better treatments for heroin overdose, or the change in the music scene from the hard rock 1970s to the pop-dominated 1980s,” Barnett says, although he did not attempt to categorise the musicians by musical style.

The concept of the “27 club” arose from the deaths of Jim Morrison, Jimi Hendrix, Janis Joplin and Brian Jones within a few years of each other, and was revived when Winehouse and Kurt Cobain died at that age. Many obscure musicians have been added to the list by fans.

Barnett agrees that if fame is like a drug there may be a “dose-related response” where the most successful performers are at greater risk of dying in their late 20s or 30s than one-hit wonders.

Barnett says the research addresses a wider observation: people are very bad at recognising coincidences. “When three people die of cancer in a street we go looking for a cause when it is more likely random chance,” he says.

Exercise Fights Colorectal Cancer
Vigorous physical activity, particularly after the age of 50, reduces the risk of some forms of colorectal cancer. The conclusion builds on work showing that sedentary jobs increase the chance of getting the same sorts of cancer.

Last year Terry Boyle, a PhD student at the University of Western Australia, found that holding a sedentary job for 10 years or more increased the risk of cancer of the distal colon and the rectum (AS, July/Aug 2011, p.11). The results were independent of the level of exercise conducted outside work hours.

Now, however, Boyle has shown that exercise is still good. “The best way to think of it is as regular types of exercise and sitting as two different spectrums,” says Boyle. “This appears to be true for a variety of diseases.”

Similarly, folate and brachial vegetable intake reduces the occurrence of these forms of cancer (AS, Sept 2009, p.6; Dec 2011, p.14–15), but exercise and diet do not appear to be substitutes for each other.

In the journal Cancer Causes Control, Boyle reported a 40% reduced risk as a result of a lifetime of physical activity. “These results suggest that vigorous activity like jogging, cycling, swimming, tennis, hockey, netball and football may be the most effective physical activities to lower the risk of bowel cancer,” Boyle says.

Patients in the study were asked about their activities during three different periods of their lives, and Boyle says that while whole-of-life activity is ideal, the period after 50 seems to be particularly crucial. “This shows that it really is never too late to start being physically active,” Boyle says.

Climate Change Species’ Final Straw
The first empirical study of the interaction of climate change and the loss of habitat has confirmed that the two make a toxic combination for endangered species. It has also revealed the conditions in which the pair combine for maximum impact.

“Human population growth has caused significant habitat degradation across the globe, typically in support of agriculture and urban development,” says lead researcher Chrystal Mantyka-Pringle from the University of Queensland. “This alone has negatively impacted many species, but combined with rises in temperature and reduced rainfall as a result of a changing climate, there could be catastrophic results for some populations. Serious declines are already a reality for many species.”

While other researchers have modelled the way these factors interact, Mantyka-Pringle is part of the first team to assemble data from species across the world to see which are faring the worst.

The answer is that regions with high maximum temperatures and where precipitation is decreasing make particularly bad homes at the moment. Temperature increases have generally been fastest in cooler climates at high latitudes and altitudes, but these are doing less damage than smaller rises where the heat was already on.

While some vertebrates are suffering more than others, Mantyka-Pringle says that all mammals, reptiles and amphibians are affected. Marine species were not considered.

On the other hand, some invertebrates did not appear to be suffering the same effects, even though most find it difficult to migrate to more climatically suitable locations. Mantyka-Pringle says this may be a reflection of the greater diversity in arthropod species included in the study.

“In areas where the effects of climate change and its interactions with habitat loss are expected to be severe, our current management approaches may be inadequate,” Mantyka-Pringle says. “In these cases, more proactive management strategies such as moving species, engineering habitat and even abandoning our efforts to save certain species in one area in favour of other areas may be more effective.”

She suggests that conservation plans should be redrawn, starting with those for species in areas with high temperatures and declining rainfall.

Areas that have experienced a reduction in precipitation (light blue) have greater pressure on endangered species. Credit: Climatic Research Unit (Mitchell & Jones 2005)

Australian Rice Has Promising Genes
Rice species found in northern Australia contain genes that could help their cultivated relatives to survive climate change.

Most Australians might be surprised to discover that native species of rice even exist, let alone have value, but Prof Robert Henry of the Queensland Alliance for Agriculture and Food Innovation says the centre for rice biodiversity may have been as close as the Torres Strait. Consequently Australia has plenty of rice species, including varieties of Oryza sativa, the once-wild species that now feeds billions.

Henry says that thousands of years of widespread cultivation have seen many of the traits that farmers have bred into rice jump to nearby wild species. Consequently wild Asian rice is far less diverse than before agriculture began. Australian species, however, have only recently been exposed to cultivated relatives, so they retain their ancient diversity.

In the Proceedings of the National Academy of Sciences Henry revealed that rice from hotter and drier parts of Australia are more genetically diverse than from other areas, and these genes could prove useful to cultivated rice exposed to a warming environment.

“We’re seeing more diversity in anti-disease and pest genes,” Henry says. “Hotter environments mean a wider array of diseases and parasites, and this is often a bigger problem for plants than the exposure to higher temperatures per se.”

Many of the types of rice are compatible for breeding with cultivated rice, and our strong understanding of the rice genome should make it relatively easy to breed them for desirable traits.

Henry notes that some desirable traits come attached to unwanted ones. He helped discover the fact that the gene that gives fragrant rice its smell comes with a reduced capacity to handle stress, which explains why this variety cannot be grown in saline environments. However, in most cases, he says, protection against disease can be bred without compromising yield.

The presence of rice contradicts the theory, promoted by author Jared Diamond, that agriculture never took off in Australia prior to European colonisation because the continent lacked appropriate species. Henry says the truth must be more complex, and suggests that a variety of suitable animal and plant species may be required to make agriculture initially attractive.

He adds that the highly variable Australian climate may also have been an impediment to agriculture’s development.

Diversity Improves Ecosystem Function
Dryland ecosystems store more carbon, release more water and have healthier soils if they contain diverse species of perennial plants, a paper in Science concludes.

While the result is very much in keeping with expectations, co-author Prof David Eldridge of the University of NSW School of Biological, Earth and Environmental Sciences says that until now theories were based on limited evidence.

“Previous research was either done at a single isolated location or experimentally with people planting monocultures, two species and so on,” Eldridge says. “Our study was over a huge area, on every continent except Antarctica, with 224 very different sites from the Mallee to Chilean alpine grasslands. Our findings suggest that plant species richness may be particularly important for maintaining ecosystem functions linked to carbon and nitrogen cycling, which sustain carbon sequestration and soil fertility.”

The fact that diverse dryland ecosystems produce more drinking water is counterintuitive – might not all those plants use up the available water? However, Eldridge explains that “perennials maintain macropores that allow water into soils. Healthy soils are better for retaining water. The classic counter-examples are monocultures where water washes straight off in storms.”

The choice was made to study perennial plants because many dryland environments have a boom/bust cycle for shorter-lived plants after rains. Thus the number of species may be more dependent on recent conditions than long-term trends. Moreover, Eldridge notes that “perennials are there all year round, so you can compare one ecosystem in summer and another in winter rather than having to do all the research at the same time.”

Eldridge notes that “climate change will reduce the ability of dryland ecosystems to perform multiple functions related to the cycling of these elements. Changing climate is also likely to reduce plant richness and increase the areas affected by desertification.” Under these circumstances species diversity may be particularly important to maintain ecological function.

Forests Emit 300% More Atmospheric Acid
Forests produce far more formic acid than previously believed, a collaboration between the University of Wollongong and Belgian scientists has revealed. The discovery, published in Nature Geoscience, may sharpen global atmospheric models.

Trees emit chemicals that oxidise to formic acid, and forests have long been known as the primary source of the most common natural atmospheric acid. However, Dr Clare Murphy of the university’s Centre of Atmospheric Chemistry says that formic acid lacks a particularly distinctive spectral signature, making its concentration hard to track. The satellite used for this research was only launched in 2006.

Researchers at the Belgian Institute for Space Aeronomy modelled the behaviour of formic acid in the atmosphere, but to make their model match satellite observations they needed to increase the output from forests by almost three times previous estimates.

“Given the uncertainty of satellite observations of formic acid they thought the problem might be with the measurements,” Murphy says. She was called upon to validate the observations using data from ground-based instruments. These confirmed the satellite data – formic acid levels emissions are indeed much higher than had been recognised.

“Normally in atmospheric science, models get adjusted by 10, maybe 20%,” Murphy says. “An increase of almost a factor of three is very unusual.”

At natural concentrations the acid alters the pH of water by 0.5, but unlike sulfuric acid it is easily processed by microbes. Consequently, Murphy says, there are no residual effects in the soil or waterways. Nevertheless, it may change the speed of atmospheric chemical reactions.