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Issues

Volume 209 Issue 3

6 August 2018

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6 August 2018 Free

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The antioxidant benefits of sleep Researchers from Columbia University in New York have found that short-sleeping fruit fly mutants shared the feature of sensitivity to acute oxidative stress, and concluded that sleep facilitates antioxidant processes. In a study published in PLoS Biology, the researchers reasoned that if sleep were required for a core function of health, animals that sleep significantly less than usual should share a defect in that core function. They examined a diverse group of short-sleeping Drosophila mutants and found that they indeed shared a common defect: they were all sensitive to acute oxidative stress. Oxidative stress results from excessive levels of free radicals that can damage cells and lead to organ dysfunction. Toxic free radicals, or reactive oxygen species, can accumulate in cells because of normal metabolism and environmental damage. If the function of sleep is to defend against oxidative stress, increasing sleep should increase resistance to oxidative stress. The effects of experimental pharmacological and genetic manipulations support this hypothesis. Finally, the authors proposed that, conversely, oxidative stress might regulate sleep. Consistent with this hypothesis, they found that reducing oxidative stress in the brain by overexpressing antioxidant genes reduced the amount of sleep. Taken together, these results point to a bidirectional relationship between sleep and oxidative stress; that is, sleep is important for defending the body against oxidative stress, and oxidative stress helps induce sleep. This work is relevant to human health because sleep disorders are associated with many diseases that are also associated with oxidative stress, such as Alzheimer, Parkinson and Huntington diseases. Sleep loss could make individuals more sensitive to oxidative stress and subsequent disease; conversely, pathological disruption of the antioxidant response could also lead to loss of sleep and associated disease pathologies. http://journals.plos.org/plosbiology/article?id=10.1371/journal.pbio.2005206 Iceman’s last meal was a fatty binge Italian researchers have conducted the first in depth analysis of the stomach contents of the Iceman, a 5300-year-old human body discovered in 1991 in the eastern Italian Alps, the oldest naturally preserved ice mummy. Their findings indicate that the Iceman’s last meal was heavy in fat. Applying a complementary -omics approach combined with microscopy, they reconstructed the Iceman’s last meal. Writing in Current Biology, the researchers showed that he had a “remarkably high proportion of fat” in his diet, supplemented by wild meat from ibex and red deer, cereals, and traces of toxic bracken. The analysis was only recently undertaken because scientists were initially unable to identify the Iceman’s stomach, as it had moved up during the mummification process. In 2009, his stomach was identified during a re-investigation of computed tomography scans. Compared with previously analysed lower intestine samples, the stomach material was extraordinarily well preserved, and contained large amounts of unique biomolecules, such as lipids, that opened new methodological opportunities for investigating questions about the Iceman’s diet. The investigators combined classic microscopic and modern molecular approaches to determine the exact composition of his diet. The broad-spectrum approach allowed them to make inferences based on ancient DNA, proteins, metabolites, and lipids. The analysis identified ibex adipose tissue as the most likely fat source; in fact, about half of the stomach contents were adipose fat. While the high fat diet was unexpected, the researchers wrote that it made sense, given the extreme alpine environment in which the Iceman lived. The analysis indicated that the wild meat was eaten fresh or perhaps dried. While the presence of toxic bracken particles is more difficult to explain, the researchers suggest the Iceman may have had intestinal problems related to parasites found in his gut and took the bracken as a medicine. On the other hand, he may have used the fern leaves to wrap food and then unintentionally ingested toxic spores. The analysis also revealed traces of the original gut bacterial community present in the Iceman’s intestine. The researchers plan to conduct further studies to reconstruct the ancient gut microbiomes of the Iceman and other mummified human remains. https://www.cell.com/current-biology/fulltext/S0960-9822(18)30703-6

Cate Swannell

Perspectives

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Letters

Neurology 6 August 2018 Free

Traumatic cricket-related fatalities in Australia: a historical review of media reports

To the Editor:I read with interest the article by Brukner and colleagues1 on traumatic cricket-related fatalities in Australia, which describes two autopsy-confirmed deaths due to subarachnoid haemorrhage following vertebral artery dissection, with a further 11 deaths suspected to be secondary to this condition. Two recent articles described a total of 230 cases of carotid or vertebral artery dissection temporally related to 45 different sports or recreational activities.2,3 The majority of episodes of arterial dissection were related to non-contact sports, including jogging, walking, swimming, golf, basketball, tennis and scuba diving. The mean age of patients was 35 years. The mechanism of non-traumatic dissection is thought to relate to shearing stress on the arterial wall with sudden neck rotation. Thus arterial dissection in golfers affected the right side in 11 of 14 patients (79%), and involved the posterior circulation in 12 of 14 patients (86%).4 Controversy regarding the association between neck manipulation and arterial dissection persists, although a retrospective case–control study found an odds ratio of 12.8 for prior neck manual therapy in individuals aged 55 years or less presenting with craniocervical arterial dissection.5 Arterial dissection may also occur spontaneously, the risk being increased in the setting of systemic lupus erythematosus, other connective tissue disorders, migraine and in the postpartum period. It is important that health professionals recognise that arterial dissection may occur spontaneously or as a result of non-contact sports and activities, and that persons of any age presenting with symptoms suggestive of anterior or posterior circulation ischaemia require urgent review and neuroimaging.

Adam Morton

Infectious diseases 6 August 2018 Free

Tackling the worsening epidemic of Buruli ulcer in Australia in an information void: time for an urgent scientific response

To the Editor:A recent article by O’Brien and colleagues1 highlights the worsening epidemic of Buruli ulcer in Australia. The steep rise in both the incidence and severity of the disease is associated with estimated health care costs of over $2.5 million per year in Victoria.1 The increase in Buruli ulcer cases in Australia parallels the increase in non-tuberculous mycobacterial (NTM) infections, especially lymphadenitis and Buruli ulcer, reported worldwide. Although this rise might be partly attributable to improved awareness and diagnostic methods, it might also be related to the discontinuation of universal bacillus Calmette–Guérin (BCG) vaccination in settings where the rate of tuberculosis has declined. Routine vaccination with BCG through the school program was discontinued in Victoria in the mid-1980s. The live-attenuated strain of Mycobacterium bovis contained in BCG vaccine shares epitopes with NTM, which makes cross-protection plausible. Our recently published meta-analysis indicates that BCG vaccination has a protective effect against NTM.2 In particular, two randomised controlled trials provide strong evidence for protection against Mycobacterium ulcerans.3,4 However, immunity might only be short lived, as the highest protection was observed in the first year after vaccination. Nevertheless, studies also report that compared with BCG-naive individuals, those who have received the BCG vaccine have smaller skin lesions,4 a shorter duration to healing5 and protection against severe forms of Buruli ulcer with multiple skin lesions.6 Buruli ulcer is a serious condition, which, despite prolonged antibiotic treatment and surgical intervention, can lead to complications such as osteomyelitis and other crippling sequelae. In light of the worsening epidemic, the protective effect of BCG vaccination should not be overlooked.

Petra Zimmermann · Adam Finn · Nigel Curtis

Careers

6 August 2018 Free

Navigating VUS Land

Dr Jodie Ingles is a cardiac genetic counsellor, navigating the winding pathways of the genetics of sudden cardiac death, and delivering help to affected families

Cate Swannell

Next Issue Volume 209 Issue 4

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News 20 August 2018 Free

News briefs

Cate Swannell

Perspectives 20 August 2018 Free

Screening for spinal muscular atrophy

Hugo Sampaio · Bridget Wilcken · Michelle Farrar

Perspectives 20 August 2018 Free

A shift in scholarly publishing practices and the growing menace of predatory journals

Peter L Munk · Tyler M Coupal · Wilfred CG Peh

Medical education 20 August 2018 Key research skills Free

Network meta-analysis in health care decision making

Bram Rochwerg · Romina Brignardello-Petersen · Gordon Guyatt

Previous Issue Volume 209 Issue 2

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News 16 July 2018 Free

News briefs

Cate Swannell

Perspectives 5 March 2018 Free

Preparation for general practice vocational training: time for a rethink

Susan M Wearne · Parker J Magin · Neil A Spike

Perspectives 16 July 2018 Free

Care of patients with chronic disease: achievements in Australia over the past decade

Mark F Harris · Ben Harris-Roxas · Andrew W Knight

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