Australasian Science: Australia's authority on science since 1938


By Stephen Luntz

Brief bites of science news.

3D Printing Tags Fish

CSIRO’s state-of-the-art 3D printing facilities are being used to manufacture titanium tags for big fish such as sharks, marlin and tuna.

“Using our Arcam 3D printing machine, we’ve been able to redesign and make a series of modified tags within a week,” said Mr John Barnes of CSIRO Titanium Technologies. “When our marine science colleagues asked us to help build a better fish tag, we were able to send them new prototypes before their next trip to sea.”

Titanium’s strength, resistance to salt water and biocompatibility make it ideal for tagging marine animals, aside from the difficulties of working the tough metal.

3D printing has revolutionised the ways in which titanium objects can be manufactured.

“Our early trials showed that the textured surface worked well in improving retention of the tag, but we need to fine-tune the design of the tag tip to make sure that it pierces the fish skin as easily as possible,” said Barnes.

Antarctic Fish Adapt to Warming

Antarctic fish are able to adapt to warming oceans, a study at the University of Canterbury has found. However, it remains to be seen whether they will be able to cope with the influx of new species that warmer waters will bring.

The oceans around the Antarctic Peninsula have warmed by 1°C in recent years, leading to an influx of crabs that previously could not survive in the frigid waters.

“The bulk of my work has been on one species of fish, borch, which acclimates to higher temperatures and radically changes its biochemistry and physiology,” says Prof Bill Davison. “This season I concentrated on a different species, emerald rock cod, which does not acclimate quite as well.”

Nevertheless, Davison found that emerald rock cod survived in aquariums with temperatures 5–6°C above what they are used to. However, he remains uncertain whether they will be able to compete with species adapted to these higher temperatures.

Ingested Capsule Measures Heat Stress

Fifty volunteer firefighters have ingested a capsule that relayed live data about their health and core body temperature before engaging in a simulation to evacuate 20 people from a burning building for the Victorian Country Fire Authority. Other information was gained from chest monitors recording respiratory heart rate and skin temperatures.

“This data has resulted in a change in work patterns and exposure times to increase the safety of firefighters. If we see their core body temperature increasing we know to remove them from the fire and put them into the rehabilitation area,” said CFA Health and Wellbeing Officer Peter Langridge. “The capsule fed us excellent live data about the heat stress and welfare of individual fire fighters and where they were located.”

Seaweed Devastated By Heat

A record-breaking heat wave caused mass dieback of a major Western Australian seaweed. “We’ve surveyed this coastline at ‘three locations – Hamelin, Marmion and Jurien bays – almost every year since 2006,” said Dr Daniel Smale of the University of Western Australia’s Oceans Institute.

In December 2010 a heat wave began, peaking in March 2011 with temperatures 5°C above normal at Jurien Bay and 2–4°C along much of the WA coast.

“During this heatwave we found that the seaweed Scytothalia dorycarpa – one of the most prominent habitat-forming species of the temperate coastline – retracted its range some 100 km because the extreme temperatures exceeded its physiological threshold,” said Smale.

Rocky reefs were left uncovered, preventing other algae from inhabiting these locations. It is expected the loss of food sources and habitat had a large effect on invertebrates and fish.

The work has been published in Proceedings of the Royal Society B. The ecological effects of this year’s summer have yet to emerge.

High Cost of Lower Backs

Lower back pain is the largest contributor to disability in the world, according to the Global Burden of Disease Study published in The Lancet.

Study leader Prof Rachelle Buchbinder of Monash University’s Department of Epidemiology said: “Our study shows that lower back pain and osteoarthritis are now ranked second only to cancer as the leading cause of disease burden in Australasia”.

Research from 47 countries was brought together to demonstrate that the contribution of back pain has been underestimated, particularly in women. Musculoskeletal conditions accounted for 15% of Australia’s death and disability burden.”

A Million Observations

Oceanographers have celebrated the millionth observation collected from 3500 Argo floats. The observation count is roughly double the number of deep water samples collected from boats in the centuries prior to Argo’s creation.

Since 1999 the floats have given scientists unprecedented knowledge about the temperature, salinity and movements of the oceans. The floats have been particularly useful in tracking the influence of global warming on salinity (AS, July/August 2012, p.11).

Nevertheless Argo Co-Chair, Dr Susan Wijffels of CSIRO Wealth from Oceans, thinks there is still a long way to go. “The world’s deep ocean environment is as hostile as that in space, but because it holds so many clues to our climate future, exploring it with the Argo observing network is a real turning point for science,” she said. “We’re still about 50 years behind the space community and its mission to reach the moon.”

Argo is international, with Australia maintaining 300 of the floats. The work has led to 1200 published papers.

Blinded by the Aspirin

Regular doses of aspirin reduce the risk of heart disease and possibly cancer, but there is a cost as well. Daily consumption increases the likelihood of age-related macular degeneration (AMD), the leading cause of blindness among the elderly.

Previous research on the topic has produced inconsistent results, so Dr Gerald Liew of the Centre for Vision Research at the Westmead Institute conducted four examinations over 15 years, a much longer period than other researchers had tried.

“Among regular aspirin users, the cumulative incidence of AMD was 1.9% at 5 years, 7% at 10 years and 9.3% at 15 years,” said Prof Paul Mitchell, director of the Centre for Vision Research. The pair reported in JAMA Internal Medicine that these figures were roughly 2.5 times the rate among people of similar age who were not taking aspirin regularly.

Given its other benefits, Mitchell and Liew suggest that only people at high risk of AMD should not take aspirin as a result of their results.

Don’t Forget Tooth Decay

Dental researchers are keen for proposed warnings on soft drinks to include the effects of tooth decay.

The association between the consumption of sugary drinks and obesity has led to a renewed set of calls for warning labels, but Dr Jason Armfield of the Adelaide School of Dentistry warns there are other problems as well. “Tooth decay carries with it significant physical, social and health implications, and we believe the risk of tooth decay should be included in any warnings relating to sweet drinks,” said Armfield.

A study of 16,800 children published by Armfield in the American Journal of Public Health found that decayed, missing or filled baby teeth were 46% more common among children who drank three or more sweet drinks per day than those who drank none.

Armfield blames acidity as well as the sugar content. He says the study confirmed the benefits of fluoridated water in reduced tooth decay.

Longer Breastfeeding Reduces Cancer

Extended breastfeeding reduces the risk of ovarian cancer, a study conducted in Guangzhou, China, has found.

Prof Colin Binns of Curtin Health Sciences says his work, published in the American Journal of Clinical Nutrition, was conducted in China in order to find sufficient cases of ovarian cancer to compare with control patients in hospital for other reasons.

“Increased ovulation heightens the risk of cell mutation which can cause ovarian cancer,” said Binns. “As breastfeeding often delays ovulation, we were able to effectively demonstrate that breastfeeding for 20 months would decrease the risk of ovarian cancer by 50%, and that the 20 months of breastfeeding could be spread over a number of children and still have the same effect.”

Ovarian cancer accounts for 4% of cancers in women. Binns described it as “difficult to diagnose, treat and having a poor prognosis”.

Sorghum Gene Could Help Feed the World

University of Queensland scientists have identified a sorghum gene that could lead to more digestible feedstocks for farm animals, and much-improved nutrition for some of world’s poorest nations. Sorghum is a staple crop in Africa but its low digestibility affects its suitability as a stable food source.

But UQ plant scientist, Professor Ian Godwin, says that selection for a specific sorghum gene could soon mean the grain from these hardy plants is much easier to digest. “While the gene identified appears to improve digestibility, the gene’s presence does not appear to diminish a sorghum plant’s growth or yield,” Godwin says.

UQ postdoc Dr Ed Gilding has demonstrated the variant gene leads to higher activity of an enzyme involved in starch biosynthesis in the developing grain. Next step in the research will be to grow significant quantities of the selected sorghum line to test its digestibility, initially in pigs and poultry.

The group’s findings are published in Nature Communications.

Experts Caution Against Voltaren

The painkiller diclofenac, which is sold in Australia as Voltaren, has a similar risk of causing heart attacks and strokes to Vioxx (rofecoxib), which was withdrawn from worldwide sales in 2004. Researchers writing in PLoS Medicine have called for diclofenac to be removed from national essential medicines lists and to have its global marketing authorisations revoked.

Dr Patricia McGettigan from The London School of Medicine and Dentistry and Dr David Henry from the University of Toronto reported that diclofenac was listed in the essential medicines lists of 74 countries, including Australia. Naproxen, a much safer alternative, is listed in just 27.

Furthermore, diclofenac sales were three times higher than naproxen. The findings demonstrate that evidence about the risks associated with diclofenac has translated poorly to clinical practice.

“Given the availability of safer alternatives, diclofenac should be delisted from national essential medicines lists,” Henry says. McGettigan concludes: “There are strong arguments to revoke its marketing authorisations globally.”

Original Alzheimer’s Case Re-examined

DNA from the patient whose autopsy led to the identification of Alzheimer’s disease has been investigated to reveal the cause of the patient’s condition.

Dr Alois Alzheimer described the beta amyloid plaques that characterise the condition based on investigations of the brain of Auguste Deter, who prior to her death had shown symptoms of early onset dementia. However, Alzheimer’s 200 slides of Deter were lost until Prof Manuel Graeber, then at the Max Plank Institute, tracked them down at the University of Munich.

Now at the University of Sydney, Graeber has re-examined the slides and confirmed that Deter was indeed suffering from Alzheimer’s disease, and used genetic analysis to show the cause.

“We found a mutation whose ultimate effect is the formation of amyloid plaques,” said Graeber. “We have revealed that Auguste Deter is one of those in which early onset of the disease is caused by mutation in a single gene.”