Research news in brief

Heroin-like fish venom offers hope for pain treatment

A fanged coral reef fish that disables its opponents with heroin-like venom could offer hope for the development of new painkillers, according to University of Queensland researcher Associate Professor Bryan Fry. In a study published in Current Biology, Professor Fry and his co-authors examined the venom of fang blennies, also known as poison-fang blennies or sabretooth blennies, of the genus Meiacanthus, which are popular as ornamental tropical aquarium fish and are found in the Pacific region, including the Great Barrier Reef. The venom of fang blennies is chemically unique. “The fish injects other fish with opioid peptides that act like heroin or morphine, inhibiting pain rather than causing it,” Professor Fry said. “The venom causes the bitten fish to become slower in movement and dizzy by acting on their opioid receptors. To put that into human terms, opioid peptides would be the last thing an elite Olympic swimmer would use as performance-enhancing substances. They would be more likely to drown than win gold.” Associate Professor Fry said the unique venom meant the fang blenny was more easily able to escape a predator or defeat a competitor. “This study is an excellent example of why we need to protect nature,” he said. “If we lose the Great Barrier Reef, we will lose animals like the fang blenny and its unique venom that could be the source of the next blockbuster pain-killing drug.”

Supplementing pre-term infants with omega-3 fats of no benefit

Research published in the New England Journal of Medicine has questioned the benefits of omega-3 fats in premature infants. The study, N3RO, led by the South Australian Health and Medical Research Institute and the Women’s and Children’s Hospital in Adelaide, was a collaboration between 13 major hospitals in Australia, New Zealand and Singapore and involved over 1200 babies born more than 11 weeks early. The study tested if supplementation with high-dose omega-3 docosahexaenoic acid (DHA), which has anti-inflammatory activity, would reduce the incidence of bronchopulmonary dysplasia (also known as chronic lung disease). The outcomes of previous studies suggested that chronic lung disease could be reduced if the amount of DHA in the diet of pre-term infants was increased to that which the baby would have received from the placenta if they hadn’t been born several months too early; this amount is more than three times the amount of DHA in breast milk or premature baby formula. Very pre-term infants were given either a supplement providing extra DHA, or a control supplement without DHA, from birth until around the time they were due to go home. The study showed that DHA supplementation not only did not reduce the risk of chronic lung disease, but marginally increased it. DHA treatment also did not alter the incidence of any of the other common complications seen in this fragile population. “The N3RO results reinforce that we need to be careful about the amounts of all nutrients, including DHA [in the nutritional management of premature infants]. More is not necessarily better,” said Dr Andrew McPhee, Statewide Director, Neonatal Services, South Australia.

Dutch study links low electromagnetic field exposure to motor neurone disease

In an observational study published in the BMJ’s Occupational and Environmental Medicine, Dutch researchers have suggested a link between workplace exposure to extremely low frequency electromagnetic fields and a doubling of the risk of developing the most common form of motor neurone disease (MND), amyotrophic lateral sclerosis (ALS) or Lou Gehrig’s disease. Previous research has suggested that ALS might be linked to workplace exposure to low frequency electromagnetic fields, electric shocks, solvents, metals and pesticides. But flaws in the design and methods of these studies have undermined the strength of the associations found. In a bid to try and avoid these pitfalls, the study authors relied on data from the Netherlands Cohort Study. This has been looking at diet and cancer and has involved more than 58 000 men and more than 62 000 women, who were all aged between 55 and 69 years when they were first entered the study in 1986. Participants who had died of MND (76 men and 60 women) were compared with around 4000 people (2411 men and 2589 women) who had been randomly selected for the purposes of the current study. Their detailed employment histories were converted into workplace exposure to solvents, pesticides, metals, low frequency electromagnetic fields and electric shocks, using a validated technique (job exposure matrices). High levels of electromagnetic field exposure were largely confined to the men, and depended on job type. These ranged from 2–25% among the men, compared with 0–2% among women. Participants’ neurological health was then tracked for an average of 17 years to see if any of them succumbed to ALS. During this time, 76 men and 60 women died of ALS. Occupational exposure to low frequency electromagnetic fields was associated with a heightened risk of developing ALS among men. Those whose jobs had exposed them to high levels of low frequency electromagnetic fields were more than twice as likely to develop ALS as those who had never been exposed through their work. The authors note that as this is an observational study, no firm conclusions can be drawn about cause and effect.

New type of bacteria linked to recurrent UTIs

Having a particular type of vaginal bacteria could make women more likely to get recurrent urinary tract infections (UTIs), according to an international study published in in PLOS Pathogens. Dormant Escherichia coli living in the bladder lining are often thought to lead to recurrent UTIs, but it wasn’t clear what reactivated them. To find out, researchers from the Washington University School of Medicine in the United States raised mice with E. coli living in their bladder lining, and exposed half to the bacterium Lactobacillus crispatus (found in high proportions in normal vagina flora) and half to Gardnerella vaginalis (which can lead to bacterial vaginosis). They found that the latter damaged the cells lining the bladder and activated the dormant E. coli, causing a new infection. These results showed that G. vaginalis could be a potential new target of treatments to prevent recurrent UTIs, the authors wrote. The results could also help explain previously found links between vaginal bacteria species, sexual activity and risk of recurrent UTIs in women.

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