Australasian Science: Australia's authority on science since 1938


By Stephen Luntz

Cannabis risk in pregnancy, IVF risks for multiple embryos, early birth better for twins and more.

Previous Cannabis a Pregnancy Risk

Consumption of marijuana doubles the chance of premature birth, Prof Gus Dekker of the University of Adelaide has reported in PLoS ONE. But it doesn’t have to be taken during pregnancy to have an effect.

A study of 3000 Adelaide and Auckland mothers found that the highest risk factor for spontaneous pre-term birth was a strong family history of low birth weight babies. This increased the risk for women in the sample by a factor of almost six.

However, cannabis use prior to pregnancy also doubled the risk, closely followed by having a mother with a history of pre-eclampsia or diabetes. A history of vaginal bleeds was also a risk factor.

Premature rupture of membranes leading to birth was associated with different risk factors, including mild hypertension, family history, low body mass and receiving hormonal fertility treatment.

Crocodile Family Tree

A study of crocodile genetics has seen 74 undergraduate Veterinary Science students from the University of Sydney become published authors of a paper in the Australian Journal of Zoology.

Over 5 years, groups of students contributed 1875 hours of fieldwork collecting genetic material from crocodiles in nine river basins in the Northern Territory.

“The result of the students’ accumulated research is a better understanding of the saltwater crocodiles’ DNA profiles and how they are distributed in different river basin populations,” said Dr Jaime Gongora, a supervisor of the project. “It will help us understand the genetic diversity of populations on crocodile ranches in the Northern Territory.”

Student Cali Willet said: “This first experience of doing research gave me a strong sense of purpose knowing it could be published”.

Large Breast Cancer Risk

Medical students at the University of Western Australia have confirmed in The Breast that large breasts are more likely to develop breast cancer. A/Prof Liz Wylie said the findings, based on mammograms from 760,000 women, demonstrated the importance of breast examination for women with the greatest risk.

The study was done on women aged over 40, with large breast size defined by the need to use larger mammogram film cassettes. The association may be a result of the presence of larger amounts of tissue in which cancer can start, or the association between larger breasts and high oestrogen levels.

Single Embryo Survivors

Single embryo transfer (SET) gives IVF babies a better start in life than the transfer of multiple embryos, the Perinatal and Reproductive Epidemiology Research Unit at the University of NSW has found.

SET has risen from 14.2% of Australian and New Zealand IVF procedures in 1999 to 67.8% in response to higher success rates and concerns about multiple deliveries. Prof Elizabeth Sullivan told the European Society of Human Reproduction and Embryology that SET babies are less likely to be stillborn or die in the first weeks of life than babies resulting from multiple embryo transfer.

“Professor Sullivan’s work supports other research that babies born after single embryo transfer are bigger, less premature and have lower abnormality rates,” said Prof Michael Chapman, head of UNSW’s School of Women’s and Children’s Health.

Early Birth Better For Twins

Early birth is usually associated with higher risk factors (AS, May 2009, p.5), but this does not apply to twins, according to Prof Jodie Dodd of the University of Adelaide's Robinson Institute.

Dodd reported in the British Journal of Obstetrics and Gynaecology that in 235 twin births, those born at 37 weeks were more likely to be a healthy size than those born at 38 weeks or later.

“Infants of a twin pregnancy are recognised to be at risk of problems during pregnancy, particularly from a slowing of the rate of growth in one or both twins,” Dodd said. “This slowing of the growth rate can result in low birth weight, which is associated with an increased need for care in the neonatal nursery in the short term and increased risk of health problems in later life.”

Dodd said 37 weeks was found to be the ideal time for mothers of twins to undergo elective birth, with fewer complications and better health outcomes for the children.

Camels Hit by Drought

Despite their reputation for surviving dry conditions, the long millennial drought hit camel numbers hard. "Between 2001 and 2008 it was estimated that there could have been as many as a million feral camels in the outback,” said Jan Ferguson of the Australian Feral Camel Management Project (AFCMP).

However, the AFCMP has reduced this figure to 750,000. “There has been a major drought, the feral camel management program has come into effect and population survey techniques have been improved, Ferguson said. “These are the main reasons overall feral camel numbers have been revised downwards.”

More than 300,000 camels were directly sighted during the AFCMP’s latest aerial survey, with the total figure based on extrapolation. The AFCMP has culled 85,000 camels, with a larger number of deaths attributed to the prolonged drought.

Television Is Promoting Diabetes

For all the concerns about children spending too much time in front of screens, Australians over 60 watch an average of an hour a day more TV than younger adults.

Dr Paul Gardiner of the University of Queensland’s School of Population Health says these 4 hours per day are a major risk factor for Type 2 diabetes.

“Up until now, most research about sitting and watching TV has been focused on children, while older adults have potentially the most to gain from changing their behaviour,” Gardiner said.

A program to encourage older people to spend less sedentary time reduced sitting time by 30 minutes per day. “The next step is to examine whether reducing this sitting time translates into improvements in health and function,” said Gardiner, who will present the results to the World Congress of Active Ageing in Glasgow.

Paternity Test Costs Ewe Little

A cheap DNA test will help sheep breeders verify paternity. “This information helps them select the best rams for mating to make sure the best genes are passed onto the next generation,” said James Kijas of CSIRO Animal, Food and Health Sciences.

In the past, stud breeders have needed to ensure that only one ram has access to ewes at mating time to determine paternity. Even maternity can be tricky, as the belief that young lambs stay close to their mother has proven inaccurate.

"A major advantage of the DNA markers we have identified is that they work through a technology that’s cheap to deliver. Our objective is a test that costs less than $20 per animal while providing much higher accuracy than any other approach,” Kijas said.

While the costs are still much higher than this, Kijas says markers have now been established to allow parental testing in any breed of sheep.

Depression Tips the Balance

Elderly people who are depressed are more likely to fall, and consequently end up with injuries such as broken bones.

“We’ve known that depression and falls are connected in older people for some time, but we were never able to determine whether depression itself or anti-depressants increase the rate of falling”, said Prof Stephen Lord of Neuroscience Research Australia.

Lord used the detailed Taiwanese health data to reveal in Age and Ageing that people over 65 who are not taking anti-depressant medication, but still show signs of depression, are more than twice as likely to fall frequently than those who feel mentally well.

“Now we know that depression and falls are interrelated, fall prevention strategies targeting older people need to also assess and treat depression to have the maximum impact”, Lord concluded.

Rats Scanned in Motion

Efforts to link brain function and behaviour now have a more powerful tool with the development of positron emission tomography (PET) scans that work while rats are moving.

"Animal imaging such as PET is almost always performed using anaesthesia to keep the animal still because any movement prevents useful three-dimensional PET images from being reconstructed," said Andre Kyme, a PhD student at the University of Sydney’s Faculty of Health Sciences.

"Anaesthetic drugs can change what's measured in the brain, and having the animal asleep prevents us from being able to image what's happening in the brain while the animal is fully responsive and able to behave normally," Kyme added.

Kyme announced in the Journal of the Royal Society Interface the successful adjustment of PET scans by tracking the animal's head at 30 frames per second. This will allow researchers to test the areas of the brain that are most active when an animal is performing a particular task.

Digital Archaeology

The University of NSW is proclaiming a new world for archaeology, allowing the sharing of data directly from the field.

“It’s time to take archaeological records out of drawers and filing cabinets,” said Dr Shawn Ross of the UNSW Faculty of Arts and Sciences. “This new system will allow information to be stored and shared in an accessible and re-useable format so that research results can be critiqued and comparative research more easily undertaken. Currently, digital data is produced through double-entry. It’s hand-written on site and then manually typed into a database, which leaves room for error,” Ross said.

The Federated Archaeological Information Management Systems (FAIMS) project will allow the production of digital datasets by archaeologists in the field, which can then be shared with anyone studying similar cultures. FAIMS has received almost $1 million dollars in federal funding to develop custom-built applications for smart phones and tablets.

SA Museum to Join Global Tissue Network

The South Australian Museum could soon join a new international "bio-bank" of institutions that look after valuable tissue samples.

The Museum is custodian to the Australian Biological Tissue Collection – the largest in the Southern Hemisphere – with nearly 125,000 samples of animals, fish, birds and plants kept in giant freezers at the Adelaide site.

The Global Genome Biodiversity Network (GGBN) is forming a pool of key biorepositories and research organisations with the intention of governing the exchange of samples, technology and information.

The Museum will be put forward by GGNB's International Steering Committee Members as a potential member.

The samples at the South Australian Museum have helped convict criminals in Australian court cases, identify illegal imports, helped scientists across the globe study biodiversity and allowed local researchers to discover and identify new species.

Many of the tissues are from species which are now extinct.