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Briefs

By Stephen Luntz

Brief bites of science news

Devil Tumour Not Weakening

The Tasmanian Devil Facial Tumour Disease (DFTD) is not among the infectious diseases that weaken or slow with time, vets at the University of Sydney have revealed in PLoS ONE.

Diseases that are too infectious and lethal can wipe out their hosts, so many evolve as they are transmitted. With DFTD having wiped out 85% of the devil population, it’s own survival is endangered if it does not stop killing devils.

“The scientific community trying to address the disease hoped it was slowing down or would show signs of slowing down, but this research proves it is not doing that and is more likely to get stronger,” said lead author Dr Kathy Belov. “We have discovered that DFTD is able to survive indefinitely because the ‘caps’ at the ends of their chromosomes are being replenished, essentially preventing ageing in this cell line.”

Co-author Dr Beata Ujvari described DFTD as “one of the oldest naturally living and continuously transferred cell lines in nature”. DFTD is the first cell line in which the telomerase protecting cells has been found to increase with time.

Twenty-Two Degree Perfection

For Brisbanites, 22°C is the perfect temperature, or at least the best for their health.

Prof Shilu Tong of QUT’s Institute of Health and Biomedical Innovation compared 784,000 ambulance attendances from 2000–07 with the temperature. “We found a 1.2% increase in total ambulance call-outs for each degree in temperature above 22° for people with cardiovascular, respiratory or other chronic conditions,” said Tong.

“We found 22°C was the threshold with minimal call-outs – for each degree below 22 there was a 1.3% increase in call-outs.

“We also studied the delayed effects of hot and cold days by looking at the relationship between exposure to hot or cold temperature and the number of call-outs on the second and third days after their exposure using a time series model.”

Previous research has shown that people adapt to the normal conditions in their city, so minimum call-out temperatures may vary by city.

Self-Organising Molecule

The University of Queensland has had a hand in the creation of a molecule that can reorganise itself in a manner reminiscent of biological molecules such as DNA.

Dr Jack Clegg of the School of Chemistry and Molecular Biosciences said that when 60 component molecules were put together they transformed themselves from a tetrahedral shape to a pentagonal prism. “Up until now we’ve only be able to do this on a very basic level,” Clegg said. “We’ve succeeded in preparing and characterising a new chemical system that is capable of structural reconstitution on receipt of one molecular signal to create a tight binding pocket for a chloride anion.”

The discovery was published in Nature Chemistry.

EEG for Stroke Minimisation

Quantitative Electroencephalogram (QEEG) monitoring can minimise the effects of stroke, a review of worldwide studies has found.

QEEGs can “help predict long-term deficits caused by stroke,” said Dr Simon Finnigan of the University of Queensland’s Centre for Clinical Research. “In addition, they could provide immediate information on how patients are responding to treatments and guide decisions about follow-on treatments, even before stroke symptoms change.”

Tissue plasminogen activator is used to dissolve blood clots that lead to stroke, but the clinicians can struggle to determine if further treatments are required. “This is where QEEG could indicate whether or not the brain is responding to the drug. Plus, it could do so up to an hour before the symptoms might improve,” said Finnigan.

“If QEEG can enable clinicians to start other treatments faster, this could help minimise brain damage and deficits.”

Good Neighbourhoods Make Good Ageing

Neighbourhood qualities such as social cohesion benefit the mental and even physical health of ageing citizens, according to Flinders University psychologist Dr Tim Windsor.

“A lot of older Australians are retired or mobility-impaired, which means they tend to spend more time in and around their homes,” said Windsor. “People who feel safe and comfortable in their environment are more likely to interact with their neighbours, and to get out and walk around, which can lead to better health and overall quality of life.”

A study of 561 Canberrans aged 55 and older confirmed participants’ level of trust and sense of belonging correlated with their health.

“Most current research on healthy ageing focuses on the personal characteristics of the individual, such as physical and cognitive health,” said Windsor. “While these things are of vital importance, we can gain a more complete picture by considering how health behaviours might be encouraged or discouraged by people’s social and neighbourhood environment.”

Redheads Don’t Need More Anaesthetic

The Australian and New Zealand College of Anaesthetists has contradicted work showing an association between hair colour and anaesthetic response.

Prof Paul Myles was concerned by a study indicating a variation in the meanocortin-1 receptor gene reduces redheads’ susceptibility to general anaesthetics. “The implications of this could be quite important because it suggests redheads may be at a greater risk of waking up during surgery, as well as waking up after surgery too quickly and in pain,” said Myles.

In Anaesthesia and Intensive Care Myles compared the time to waking of 468 patients undergoing general anaesthesia. Although the redheads awoke faster, this was a result of a higher proportion of redheaded women. “We already know that women are less sensitive to general anaesthetics and, once we accounted for gender imbalance, the effect of hair colour was negligible,” said Myles.

However, Myles acknowledged that the topic requires more research, as “the genes that determine both the hair colour and pale skin of redheads probably influence how anaesthetic drugs act on the brain”.

Pollution Comes by Ship

Approximately 30% of the nitric oxide emissions in the Australian region are released from ship engine exhausts, a CSIRO and Australian Maritime College study has found.

Unlike nitrous oxide, nitrogen oxide is not a greenhouse gas, but it contributes to smog. In Australia’s largest cities, seasonally prevailing winds blow air from the port and nearby waters over heavily populated areas.

“We’re seeing increasing regulation of land-based emissions but limited regulation of shipping emissions, and expect that in the near future there will be a need to monitor more closely emissions from shipping,” said Dr Ian Galbally of CSIRO Marine and Atmospheric Research. “There is limited knowledge about the emissions from ships in coastal regions and ports in Australia and the effects of these emissions on air quality in the surrounding urban regions.”

The study, published in Air Quality and Climate Change, also estimates that shipping accounts for 20% of sulphur oxides in Australia’s region.

Less Devilish Devils

Tasmanian devils might survive the devil facial tumour disease (DFTD) that is plaguing them, but only by losing some of their characteristic aggression, a study in the Journal of Animal Ecology suggests.

“Our results – that devils with fewer bites are more likely to develop DFTD – were very surprising and counterintuitive,” said Dr Rodrigo Hamede of the University of Tasmania’s School of Zoology. “In most infectious diseases there are so-called ‘super-spreaders’, a few individuals responsible for most of the transmission. But we found the more aggressive devils, rather than being super-spreaders, are super-receivers.”

It appears biting an infected devil is more dangerous than being bitten by one, placing the more aggressive devils at a disadvantage. Hamede says that management strategies may need to look at conserving less aggressive devils as those most likely to have a future.

Ultraviolet Increase Tracked

Ultraviolet radiation increased by 2–6% across Australia over the period 1959–2009, the Bureau of Meteorology has found. Almost all of the increase occurred after the mid-1980s as ozone depletion took its toll.

Winter radiation has risen almost twice as fast as summer radiation, which the Bureau’s Dr Lilia Lemus-Dushamps described as an issue in northern Australia. “Pleasant winter temperatures in these regions lead to more outdoor activities and extended exposure to damaging UV,” she said. Nevertheless, UV levels have risen faster across southern Australia, reflecting the influence of the Antarctic ozone hole.

Ozone depletion is one of the major reasons skin cancer rates continue to increase, despite the success of SunSmart campaigns on younger generations. Recent modelling indicates that phasing out of chlorofluorocarbons under the Montreal Protocol will prevent two million skin cancers a year worldwide by 2030, but the atmosphere is taking time to repair.

Fish With Napoleon Complexes

Small male desert goby fish are more aggressive in defending their nests than their larger counterparts, Dr Bob Wong of the Monash School of Biological Sciences has reported in PLoS ONE.

Male desert gobies construct nests and win females to them. They fan the eggs regularly to keep them oxygenated while also scaring off threats.

“In the animal world, competing males are expected to partake in a drawn out escalation of aggression to avoid the risks of being injured by a superior opponent,” said Wong. “We found the aggression of males was not affected by the presence of females and perceived mating opportunities or larger male intruders. Instead their aggression was related to their size. In particular, smaller males attacked sooner and with greater intensity compared to larger males.”

Wong’s co-author, Dr Andreas Svennson of Linnaeus University, suggested that small males depend on scaring off intruders before their size can be assessed.