Culture

Geneticists exploring the dark heart of the human genome have discovered big chunks of Neanderthal and other ancient DNA. The results open new ways to study both how chromosomes behave during cell division and how they have changed during human evolution.

Centromeres sit in the middle of chromosomes, the pinched-in "waist" in the image of a chromosome from a biology textbook. The centromere anchors the fibers that pull chromosomes apart when cells divide, which means they are really important for understanding what happens when cell division goes wrong, leading to cancer or genetic defects.

But the DNA of centromeres contains lots of repeating sequences, and scientists have been unable to properly map this region.

"It's the heart of darkness of the genome, we warn students not to go there," said Charles Langley, professor of evolution and ecology at UC Davis. Langley is senior author on a paper describing the work published in the journal eLife.

Langley and colleagues Sasha Langley and Gary Karpen at the Lawrence Berkeley Laboratory and Karen Miga at UC Santa Cruz reasoned that there could be haplotypes -- groups of genes that are inherited together in human evolution -- that stretch over vast portions of our genomes, and even across the centromere.

That's because the centromere does not participate in the "crossover" process that occurs when cells divide to form sperm or eggs. During crossover, paired chromosomes line up next to each other and their limbs cross, sometimes cutting and splicing DNA between them so that genes can be shuffled. But crossovers drop to zero near centromeres. Without that shuffling in every generation, centromeres might preserve very ancient stretches of DNA intact.

The researchers looked for inherited single nucleotide polymorphisms -- inherited changes in a single letter of DNA -- that would allow them to map haplotypes in the centromere.

They first showed that they could identify centromeric haplotypes, or "cenhaps," in Drosophila fruit flies.

That finding has two implications, Langley said. Firstly, if researchers can distinguish chromosomes from each other by their centromeres, they can start to carry out functional tests to see if these differences have an impact on which piece of DNA is inherited. For example, during egg formation, four chromatids are formed from two chromosomes, but only one makes it into the egg. So scientists want to know: Are certain centromere haplotypes transmitted more often? And are some haplotypes more likely to be involved in errors?

Secondly, researchers can use centromeres to look at ancestry and evolutionary descent.

Turning to human DNA, the researchers looked at centromere sequences from the 1000 Genomes Project, a public catalog of human variation. They discovered haplotypes spanning the centromeres in all the human chromosomes.

Haplotypes from half a million years ago

In the X chromosome in these genome sequences, they found several major centromeric haplotypes representing lineages stretching back a half a million years. In the genome as a whole, most of the diversity is seen among African genomes consistent with the more recent spread of humans out of the African continent. One of the oldest centromere haplotype lineages was not carried by those early emigrants.

In chromosome 11, they found highly diverged haplotypes of Neanderthal DNA in non-African genomes. These haplotypes diverged between 700,000 to a million years ago, around the time the ancestors of Neanderthals split from other human ancestors. The centromere of chromosome 12 also contains an even more ancient, archaic haplotype that appears to be derived from an unknown relative.

This Neanderthal DNA on chromosome 11 could be influencing differences in our sense of smell to this day. The cells that respond to taste and smell carry odorant receptors triggered by specific chemical signatures. Humans have about 400 different genes for odorant receptors. Thirty-four of these genes reside within the chromosome 11 centromere haplotype. The Neanderthal centromeric haplotypes and a second ancient haplotype account for about half of the variation in these odorant receptor proteins.

It's known from work by others that genetic variation in odorant receptors can influence sense of taste and smell, but the functional effects of the variation found in this study are yet to be discovered and their impact on taste and smell analyzed.

Scientists in the FinnBrain research project of the University of Turku, Finland, discovered that the gut microbes of a 2.5-month-old infant are associated with the temperament traits manifested at six months of age. Temperament describes individual differences in expressing and regulating emotions in infants, and the study provides new information on the association between behaviour and microbes. A corresponding study has never been conducted on infants so young or in the same scale.

Rodent studies have revealed that the composition of gut microbiota and its remodelling is connected to behaviour. In humans, gut microbes can be associated with different diseases, such as Parkinson's disease, depression and autism spectrum disorders, but little research has been conducted on infants.

Doctoral Candidate, Doctor Anna Aatsinki from the FinnBrain research project at the University of Turku, Finland, discovered in her study on 303 infants that different temperament traits are connected with individual microbe genera, microbial diversity and different microbe clusters.

"It was interesting that, for example, the Bifidobacterium genus including several lactic acid bacteria was associated with higher positive emotions in infants. Positive emotionality is the tendency to experience and express happiness and delight, and it can also be a sign of an extrovert personality later in life," says Aatsinki.

Temperament Can Predict Later Development

One of the findings was that greater diversity in gut bacteria is connected to lesser negative emotionality and fear reactivity. The study also considered other factors that significantly affect the diversity of the microbiota, such as the delivery method and breastfeeding.

The findings are interesting as strong fear reaction and negative emotionality can be connected to depression risk later in life. However, the association with later diseases is not straightforward and they are also dependent on the environment.

"Although we discovered connections between diversity and temperament traits, it is not certain whether early microbial diversity affects disease risk later in life. It is also unclear what are the exact mechanisms behind the association," adds Aatsinki.

"This is why we need follow-up studies as well as a closer examination of metabolites produced by the microbes."

A new study in the Faculty of Public Health's Journal of Public Health finds that tobacco and alcohol usage are extremely common in British reality television shows.

The researchers measured depictions of alcohol and tobacco products on Celebrity Big Brother, Made in Chelsea, The Only Way is Essex, Geordie Shore, and Love Island, all airing on UK channels for a total of 112 episodes between January and August 2018. The researchers measured the number of one-minute intervals containing tobacco and/or alcohol imagery, including actual use, implied use, tobacco or alcohol related materials, and product-specific branding, and estimated viewer exposure to the imagery on screen.

Researchers here combined audience viewing figures with mid-year population estimates for 2017 to estimate overall and individual impressions--separate incidents seen--by age group for each of the coded episodes.

Alcohol content appeared in all 112 episodes and in 2212 one-minute intervals, or 42% of all intervals studied. 18% of intervals included actual alcohol consumption, while 34% featured inferred consumption, predominantly characters holding alcoholic beverages. The greatest number of intervals including any alcohol content occurred in Love Island. Alcohol branding occurred in 1% of intervals and was most prevalent in Geordie Shore (51 intervals, 69% of episodes). Forty brands were identified, the most common being Smirnoff vodka (23 intervals, all but one of which occurred in Geordie Shore).

Tobacco content appeared in 20 episodes, in 110 or 2% of all intervals studied. Almost all (98%) of this content occurred in a single reality TV series, Celebrity Big Brother. This included actual tobacco use, inferred tobacco use, and tobacco paraphernalia. Tobacco branding was not present.

When all the data were combined with audience viewing figures and population estimates, the researchers estimate that the 112 episodes delivered 4.9 billion overall alcohol impressions to the UK population, including 580 million to children under the age of 16, as well as 214 million overall tobacco impressions, including 47 million to children under 16.

"Recent data shows that 44% of 11-15 year-olds in England have had an alcoholic drink, and 19% have tried smoking. Starting to smoke or drink alcohol at a young age is a strong predictor of dependence and continued use in later life," said the study's lead author, Alexander Barker. "Given that seeing alcohol or tobacco imagery in the media promotes use among young people, this study therefore identifies reality television shows as a major potential driver of alcohol and tobacco consumption in young people in the UK. Tighter scheduling rules, such as restricting the amount of content and branding shown in these programmes, could prevent children and adolescents from being exposed to the tobacco and alcohol content."

Terminally ill patients who request that physicians make decisions on their behalf are more likely to receive aggressive treatments in the weeks before they die, according to a Rutgers study.

The study, published in the Journal of Pain and Symptom Management, is the first to examine if personal beliefs and attitudes of both patients and physicians affect end-of-life treatments that can be painful and risky.

The findings call attention to the fact that patients are accepting aggressive treatments and highlight the need for better education about end-of-life care.

"Some physicians are very comfortable taking over the decision-making for their terminally ill patients. An important and surprising finding is that when physicians do take charge of treatment decisions, patients are more likely to receive aggressive interventions at the end of life," said lead author Paul Duberstein, chair of the Department of Health Behavior, Society and Policy at Rutgers School of Public Health. "As a result, patients end up in intensive care units or emergency rooms in the days before death, even though most people would rather die peacefully at home.

The researchers examined chemotherapy use and hospitalizations or emergency department visits in the last 30 days of life of 265 patients who had been cared for by 38 oncologists. They found that patients of physicians who were comfortable offering aggressive medical interventions were more likely to receive chemotherapy and endure difficult hospitalizations in the days and weeks before dying. Patients who had unfavorable attitudes toward palliative care and those who wanted to try medically unproven cancer treatments were also more likely to receive aggressive interventions.

"Many studies have examined doctor's attitudes, but few have examined if doctors' attitudes affect end-of-life care," Duberstein said. "We found that doctors' attitudes can have detrimental impacts and prevent those who are close to death from receiving the emotional support needed at that time."

The findings show the importance of providing patients with access to information about how doctors handle high-stakes treatment decision-making. "That information is not publicly available, but it needs to be," he said.

The findings also have clinical and ethical implications regarding the care of patients with advanced diseases.

"We need to do a much better job teaching doctors about the psychology of death and dying, improving the way we educate the public about the benefits of palliative care and providing care for patients and families with advanced disease," Duberstein said.

DNA, the hereditary material, may have appeared on Earth earlier than has been assumed hitherto. Ludwig-Maximilians-Universitaet (LMU) in Munich chemists led by Oliver Trapp show that a simple reaction pathway could have given rise to DNA subunits on the early Earth.

How were the building-blocks of life first formed on the early Earth? As yet, only partially satisfactory answers to this question are available. However, one thing is clear: The process of biological evolution that has given rise to the diversity of life on our planet must have been preceded by a phase of chemical evolution. During this 'prebiotic' stage, the first polymeric molecules capable of storing information and reproducing themselves were randomly assembled from organic precursors that were available on the early Earth. The most efficient replicators subsequently evolved into the macromolecular informational nucleic acids - DNA and RNA - that became the basis for all forms of life on our planet.

For billions of years, DNA has been the primary carrier of hereditary information in biological organisms. DNA strands are made up of four types of chemical subunits, and the genetic information it contains is encoded in the linear sequence of these 'nucleosides'. Moreover, the four subunits comprise two complementary pairs. Interactions between two strands with complementary sequences are responsible for the formation of the famous double helix, and play a crucial role in DNA replication. RNA also has vital functions in the replication of DNA and in the translation of nucleotide sequences into proteins.

Which of these two types of nucleic acid came first? The unanimous answer to that question up to now was RNA. Plausible models that explain how RNA molecules could have been synthesized from precursor compounds in prebiotic settings were first proposed decades ago, and have since received substantial experimental support. Moreover, its conformational versatility allows RNA both to store information and to act as a catalyst. These insights have led to the idea of an 'RNA world' that preceded the emergence of DNA, which is now well established among specialists. How then were the first DNA subunits synthesized? The generally accepted view is that this process was catalyzed by an enzyme - a comparatively complex biomolecule whose emergence would have required millions of years of evolution.

But now a team of chemists led by LMU's Professor Oliver Trapp has proposed a much more direct mechanism for the synthesis of DNA subunits from organic compounds that would have been present in a prebiotic environment. "The reaction pathway is relatively simple," says Trapp, which suggests it could well have been realized in a prebiotic setting. For example, it does not require variations in reaction parameters, such as temperature. In Trapp's experiments, the necessary ingredients are water, a mildly alkaline pH and temperatures of between 40 and 70°C. Under such conditions, adequately high reaction rates and product yields are achieved, with high selectivity and correct stereochemistry.

Each of the nucleoside subunits found in DNA is made up of a nitrogen-containing base and a sugar called deoxyribose. Up to now, it was thought that deoxynucleosides could only be synthesized under prebiotic conditions by directly coupling these two - preformed - components together. But no plausible non-enzymatic mechanism for such a step had ever been proposed. The essential feature of the new pathway, as Trapp explains, is that the sugar is not linked to the base in a single step. Instead, it is built up on the preformed base by a short sequence of reaction steps involving simple organic molecules such as acetaldehyde and glyceraldehyde. In addition, the LMU researchers have identified a second family of possible precursors of DNA in which the deoxyribose moiety is replaced by a different sugar.

According to the authors of the study, these results suggest that the earliest DNA molecules could have appeared in parallel with RNA - some 4 billion years ago. This would mean that DNA molecules emerged around 400 million years earlier than previously thought.

New research from the Danish psychiatric project, iPSYCH, shows that a specific gene is associated with an increased risk of cannabis abuse. The gene is the source of a so-called nicotine receptor in the brain, and people with low amounts of this receptor have an increased risk of cannabis abuse.

Cannabis is the most commonly used illegal drug in both Denmark and internationally, and around one in ten users becomes addicted to the drug. Researchers from iPSYCH have discovered a gene that they associate with the abuse of cannabis.

"We discovered that the disorder was associated with a genetic variant. This variant affects how much of a certain nicotine receptor is formed in the brain," explains Associate Professor Ditte Demontis from Aarhus University, who is behind the study.

The genetic variant discovered by the researchers affects how much of a specific nicotine receptor is formed. People who have less of this receptor in the brain are at greater risk of becoming cannabis abusers.

Ditte Demontis and her colleagues used a nationwide Danish cohort to analyse the complete genome of more than 2,000 cannabis abusers and the genome of 50,000 control subjects. The researchers subsequently repeated these findings in an analysis of a further 5,500 cannabis abusers and more than 300,000 control subjects.

The researchers also included genetic data from studies in which researchers examined the underlying genetics for cognition such as e.g. the ability to complete an education.

Here, they found that people with a higher number of genetic variants associated with impaired cognition also have an increased risk of cannabis abuse.

"People who abuse cannabis often do worse in the education system, and our results show that this can be partly explained by genetics. That is to say that people with an abuse problem have more genetic variations in the genome which increase the risk of cannabis abuse, while at the same time negatively affecting their ability to get an education," explains Ditte Demontis.

The study is the first of its kind on this scale and represents a step towards understanding the particular biological mechanisms, which lie behind the abuse of cannabis.

"We need to undertake even more research into how the genetic differences in the genome contribute to the development of cannabis abuse, and we need to map out the precise biological mechanisms that lead to one person having a higher risk of becoming a substance abuser than another. Our hope is to be able to improve treatment and perhaps in the long-term even prevent this abuse," says Ditte Demontis.

Singapore, 18 June 2019 - How dormant neural stem cells in fruit flies are activated and generate new neurons is described in a new research study by Duke-NUS Medical School. The findings could potentially help people with brain injury or neuronal loss, if similar mechanisms apply in humans.

Publishing in PLOS Biology, the research team, led by Associate Professor Wang Hongyan, Deputy Director of Duke-NUS' Neuroscience and Behavioural Disorders Programme and lead author of the study, described the process and molecules involved in reactivating fruit flies' (also known by their scientific name, Drosophila) dormant neural stem cells, which can activate and generate new neurons. The ability of neural stem cells to switch from their dormant state and begin to proliferate is crucial in the brain. Until now, very little was known about how dormant neural stem cells become active.

Assoc Prof Wang and colleagues investigated what factors are at play in developing Drosophila brains at the larval stage. They discovered that a protein complex called CRL4 is essential for the reactivation of neural stem cells as it downregulates a pathway that normally keeps neural stem cells in the dormant state. They saw that CRL4 forms a protein complex with the tumour suppressor Warts, a core component of the pathway, and that CRL4 targets Warts for degradation to trigger reactivation.

The ability to awaken dormant neural stem cells could stimulate new neurons to compensate for brain injury or the neuronal loss seen in neurodegenerative diseases, such as Parkinson's or Alzheimer's. Future work is required to confirm that CRL4 and the pathway it regulates works in a similar manner in mammalian brains.

"Mutations of human Cullin4B, a core component of the CRL4 complex, are associated with mental retardation and cortical malformations," said Assoc Prof Wang. "Our work identifies the mechanisms behind CRL4 in fruit fly brain development and we plan to conduct further research to see if the same proteins are in play in mammals. Ultimately, our hope is that greater understanding and stimulation of these cells could eventually lead to therapeutic treatment of neurodevelopmental and neurodegenerative diseases."

Professor Patrick Casey, Senior Vice Dean for Research at Duke-NUS, noted, "The prevalence of neurodegenerative diseases, such as Parkinson's, is projected to increase in Singapore and worldwide in the coming decades, in tandem with increasingly ageing populations. Basic science research to better understand how the brain works, such as this study, is critical to developing new therapeutic strategies to enhance care for such diseases."

Toronto - Canada is stunting its own economy and blocking businesses from reaping the benefits of innovation by clinging to protectionist policies that curb foreign investment, a new study from the University of Toronto's Rotman School of Management says.

Relaxing restrictions to bring Canada more in line with other democratic market economies would significantly boost productivity, it says. Put into hard numbers, that adds up to an extra 137,400 jobs or $9.6 billion in annual earnings -- $648 per worker.

"Canada is far more restrictive than what most people would believe," says Walid Hejazi, an associate professor of economic analysis and policy who co-authored the study with fellow Rotman professor Daniel Trefler, the Douglas and Ruth Grant Canada Research Chair in Competitiveness and Prosperity.

"Our protectionist policies are inhibiting innovation and productivity in the Canadian economy. As a result, Canada is losing its position globally on several metrics," adds Prof. Trefler.

Foreign investment restrictions are typically defended by concerns that domestic industry will be swamped or swallowed up and jobs lost in the face of wide-open foreign competition. But the evidence, says the study, shows foreign investment and competition ultimately lead to higher domestic productivity by introducing and encouraging industries to adopt more efficient and innovative practices.

The study used measures of foreign investment restrictiveness for member countries published by the Organization for Economic Cooperation and Development in 2010.

Focusing on three key business service sectors - financial, telecommunications and air transportation services - the study found that Canada's measure was above the OECD average and the highest in the G7, except for Japan.

Given that those three sectors impact many "downstream" businesses that rely on them to run and grow their own enterprises, such a high level of protectionism poses a serious cramp on productivity throughout the economy, the study points out.

Bringing Canada in line with the OECD average would raise labour productivity by 0.79 percent economy-wide. While that may not sound like much, it's significant in economic terms.

"These are big numbers, from a policy perspective," says Prof. Hejazi. "We anticipated that the numbers would be large, but not this large."

A key contributor to Canada's higher-than-average bar for foreign investment is a review mechanism, in which all foreign investment proposals above a certain threshold are automatically subject to assessment by the Canadian government for their potential net benefit to the country.

Geospatial scientists have developed a new program to monitor street signs needing replacement or repair by tapping into Google Street View images.

The fully-automated system is trained using AI-powered object detection to identify street signs in the freely available images.

Municipal authorities currently spend large amounts of time and money monitoring and recording the geolocation of traffic infrastructure manually, a task which also exposes workers to unnecessary traffic risks.

Results just published in the journal of Computers, Environment and Urban Systems show the system detects signs with near 96% accuracy, identifies their type with near 98% accuracy and can record their precise geolocation from the 2D images.

Study lead author and RMIT University Geospatial Science Honours student, Andrew Campbell, said the proof-of-concept model was trained to see 'stop' and 'give way'(yield) signs, but could be trained to identify many other inputs and was easily scalable for use by local governments and traffic authorities.

"(Municipal authorities) have requirements to monitor this infrastructure but currently no cheap or efficient way to do so," Campbell said.

"By using free and open source tools, we've now developed a fully automated system for doing that job, and doing it more accurately."

The team found during investigations that mandatory GPS location data in existing street sign databases was often inaccurate, sometimes up to 10m off.

"Tracking these signs manually by people who may not be trained geoscientists introduces human error into the database. Our system, once set up, can be used by any spatial analyst - you just tell the system which area you want to monitor and it looks after it for you," Campbell said.

Campbell credited the project's initial concept to his industry mentor at Alpine Shire Council and RMIT Geospatial Science alumnus, Barrett Higman.

RMIT geospatial scientist and project co-lead, Dr Chayn Sun, said the fact that some councils were already attaching cameras onto rubbish trucks to gather street footage showed how valuable visual data were becoming, given what technology could now do with it.

"This imagery is critical for local governments in monitoring and managing assets and with the huge amount of geospatial applications flourishing, this information will only become more valuable," Sun said.

"Ours is one of several early applications for this to meet a specific industry need but a whole lot more will emerge in coming years."

Sun said footage from other sources, like that from rubbish truck cameras or any other geo-referenced imagery of the road network collected by municipal authorities, could also be fed into the system.

"Where footage is already being gathered, our research can provide councils with an economical tool to drive insights and data from this existing resource," she said.

Adequate intake of protein is associated with a reduced risk of frailty and prefrailty in older women, according to a new study from the University of Eastern Finland and Kuopio University Hospital. Adequate protein intake was defined as at least 1.1 g per kg of body weight. The findings were published in European Journal of Nutrition.

Frailty is a multidimensional condition common in older adults, and those affected are at an elevated risk of dependence and mobility loss, fall, fracture, multimorbidity and mortality. Evidence shows a strong link between frailty and malnutrition, and protein may be the most important nutrient at play, mostly through its effect on muscle health. The Nordic Nutrition Recommendations (2012) suggest protein intake of 1.1-1.3 g per kg of body weight as adequate for preserving physical capacity in older adults. However, there is a paucity of data regarding the association of protein intake with frailty. The newly published study examined associations between protein intake and protein sources with frailty status in older women.

Participants were 440 women aged 65--72 years enrolled in the Osteoporosis Risk Factor and Prevention-Fracture Prevention Study. Their protein intake in g per kg of body weight was calculated using a three-day food record at baseline in 2003--2004. At the three-year follow-up in 2006--2007, frailty phenotype was defined as the presence of three or more, and prefrailty as the presence of one or two of the Fried criteria: low grip strength, low walking speed, low physical activity, exhaustion (defined using a low life satisfaction score), and weight loss of more than five per cent.

The study shows that getting the recommended amount of dietary protein was associated with a lower risk of frailty and prefrailty in older women. Moreover, the consumption of animal protein was associated with a lower likelihood of frailty. The recommended protein intake (1.1-1.3 g per kg of body weight) for an older person weighing 70 kg corresponds to a minimum intake of 77 g of protein. To illustrate, the protein content of a chicken breast per portion is 25 g, one boiled egg 6 g, and two slices of whole grain bread 6 g.

"The public health recommendation is to eat an optimal diet with an adequate intake of protein. Adequate protein intake is important for muscle health and, according to the new results, may also prevent frailty. However, further research is still required in this area," Senior Lecturer Arja Erkkilä from the University of Eastern Finland concludes.

PHILADELPHIA - It's no secret that Americans are politically divided, but a new report offers hope that Democrats and Republicans find common ground on at least one issue: the role of "evidence" in developing and shaping health laws. Strong bipartisan support exists for a greater use of "evidence" - defined as information based on reliable data and produced by statistical methods - in development of health policy in the United States. The study is published today in Translational Behavioral Medicine from a researcher at Drexel University's Dornsife School of Public Health.

In a 2018 public opinion survey, 532 Americans were asked to what extent six factors "should have" and "currently have" influence on health policy decisions made by members of the United States Congress, including industry interests, evidence, and budget costs. The data was weighted to be representative of the U.S. adult population.

"Evidence" as well as "citizens' desires," were the factors most often identified by both Democrats and Republicans as those that should have the most influence. While members of both parties agreed on the most important factors that should shape policy, they were comparably cynical about whether their voices are being acted upon. Although 59 percent of respondents said that evidence should have "a lot of influence" on policy, only 11 percent said that evidence currently has "a lot of influence" on those decisions.

Additionally, more than half of respondents said that desires of citizens should have "a lot of influence," but only 14 percent reported that citizens actually have "a lot of influence" on policy. This disconnect was also found in the role of pharmaceutical companies' lobbying efforts. Just six percent said the interests of pharmaceutical companies should have a lot of influence, but 44 percent said they felt those companies currently have "a lot of influence."

"There is a wide gap between what Americans think should influence health policymaking in U.S. Congress and what they think actually does influence policy," said author Jonathan Purtle, DrPh, MPH, an assistant professor of Health Management and Policy in the Dornsife School of Public Health. "Across the political spectrum, Americans want evidence to play a much stronger role."

Political division has been well-documented. A 2017 Pew Research Center report of 5,000 surveyed Americans notes record levels of division between Democrats and Republicans on many political values, including race, immigration, the environment and other issues.

As prior studies have shown that public opinion can influence decisions made by policymakers, Purtle suggests that members of the U.S. Congress may be held more accountable by efforts to disclose evidence behind specific policy decisions.

Although the findings show no statistically significant difference across party lines on the role of evidence and citizens' desires in health policy, Purtle notes that "evidence" is a flexible idea that can be altered to support an individual's pre-existing policy preferences. He adds that future research should look at how opinions about the influence that evidence should have on policymaking vary when evidence unequivocally supports legislation decisions that are counter to citizens' preferences.

NEW YORK (June 18, 2019) -- Large numbers of healthcare workers risk transmitting respiratory viruses to patients and co-workers by attending work even when they have symptoms, according to a study published today in Infection Control & Hospital Epidemiology, the journal for the Society for Healthcare Epidemiology of America. The study found that 95 percent of people working in healthcare settings have worked while sick, most often because the symptoms were mild or started during their workday.

"We found that physicians and people working in areas that required the most intensive contact with patients were less likely than other workers to stay home or to leave work if symptoms progressed after the start of the day," said Brenda Coleman, PhD, clinical scientist in the Infectious Disease Epidemiology Research Unit at Mount Sinai Hospital, Toronto, and lead author of the study. "Managers and senior staff need to both model and insist on workers staying home when symptomatic as it protects both patients and coworkers from infection."

Hospital-acquired respiratory viral infections are recognized as causing significant illness and even deaths as well as increased healthcare costs. The Centers for Disease Control and Prevention recommends that healthcare workers with fever and respiratory symptoms consider temporary reassignment or exclusion from work for while symptomatic, but working with symptoms of an acute respiratory viral illnesses is common, with as many as 92 percent of healthcare workers reporting to work while symptomatic.

Researchers conducted a four-season prospective cohort study of influenza and other respiratory illnesses in nine Canadian hospitals in Toronto, Hamilton, and Halifax. Healthcare workers in acute care hospitals who worked more than 20 hours a week were asked to complete daily online illness diaries whenever they developed symptoms. Illness diaries collected information about symptoms, possible exposure, attendance at work, reason for work or absence, and medical consultations.

A total of 10,156 illness diaries were completed by 2,728 participants. Diaries of participants that were not scheduled to work were excluded, leaving 5,281 remaining diaries for analysis. Analysis of the diaries found that 69 percent of participants said that they worked during an illness because they had mild symptoms and felt well enough to work, 11 percent said they had things to do at work, 8 percent felt obligated to work, and 3 percent stated that they could not afford to stay home. Half of the participants reported episodes of acute respiratory viral illness during each influenza season, with 95 percent of those who reported an acute respiratory viral illness working one or more days of their illness. Seventy-nine percent said they were entitled to paid sick leave.

These findings suggest the need to educate healthcare workers, managers, workplace health and safety and infection control staff, and administrators about the risk of transmission associated with respiratory viral infection, to clarify what symptoms require exclusion from work, and to develop and implement policies for working while symptomatic, Coleman said.

Though the study was conducted in Canada, researchers believe the results also apply to the United States since hospitals in both countries follow similar recommendations to prevent the spread of disease, including standard, droplet and contact precautions as well as vaccination requirements. "There are likely as many differences between states as there are between Canadian and U.S. institutional recommendations." Coleman said

Amsterdam, June 18, 2019 - Charcot-Marie-Tooth (CMT) disease is the most common inherited neurological disorder affecting peripheral motor and/or sensory nerves in humans. Monogenic disorders like CMT1A, CMT's most prevalent subtype, are caused by a single gene defect. However, its clinical presentation and severity can vary widely, leading doctors to wonder what factors might be responsible for these differences. A study published in the Journal of Neuromuscular Diseases reveals that while all patients with CMT1A share a single gene defect, at least four clinical characteristics were found to be associated with secondary modifying genes.

"Modifier studies offer a significant pathway to additional therapeutic target discovery and underscore that monogenic disorders are a lot more complex than previously thought," explained lead investigator Stephan Züchner, MD, PhD, of the Department of Human Genetics and Hussman Institute for Human Genomics of the University of Miami. "Our study is a first in CMT, and one of the largest in all of rare diseases, to explore - genome wide and unbiased - the correlation of clinical outcome and genetic modifier loci. This study also proves the feasibility of this approach and should encourage scientists to pursue data aggregation and standardized protocols in rare disease in order to obtain a much more complete picture of the genetic architecture of rare disorders."

The study focused on close to 1,000 patients of European ancestry with CMT1A enrolled in a standard protocol over nine years. Researchers genotyped more than 600,000 genomic markers using DNA samples from these patients and performed a case-only genome-wide association study (GWAS) to identify potential genetic association with particular clinical outcomes in a subset of 644 individuals of European ancestry.

Researchers searched for single nucleotide polymorphisms (SNPs), which are specific variations at a single position in a DNA sequence among individuals. Then they investigated whether the SNPs could be statistically associated with any of 14 clinical manifestations of CMT1A, such as disease severity, using the CMT neuropathy score (CMTNS), motor symptoms, sensory symptoms, muscle strength, foot deformity, scoliosis, and hearing loss. "This allowed us to screen genome wide for markers that indicate a correlation with particular clinical outcomes," said Dr. Züchner.

We identified significant genomic loci that contained candidate genes. Four "subphenotypes" of CMT1A (difficulty with using eating utensils, hearing loss, decreased ability to feel, and CMTNS score) were found to be associated with particular SNPs or chromosomal regions. For example, hearing loss affected 16% of 364 individuals. In these individuals, "suggestive associations signals" were found on chromosome 5. The association signal was supported by multiple SNPs around a lead SNP. Other nearby genes were also found to be affected, none of which had previously been implicated in hearing loss.

"This is still a high-level statistical exploration and the benefit for individual patients is not yet fully understood. In the best-case scenario, we will be able to use such modifier genetic information to predict more precisely the natural course of disease in a single person," commented Dr. Züchner. "As new genetic therapies and small molecular screening technologies mature, such targets can be exploited much faster."

The investigators anticipate that GWAS analysis can be applied to other inherited disorders in order to provide a more nuanced understanding of all genetic anomalies that might contribute to the disease.

According to the Muscular Dystrophy Association, CMT1A accounts for around 60% of CMT1 cases. It is an autosomal dominant demyelinating form of CMT. CMT1 is characterized by muscle weakness, atrophy, and changes in sensation, mostly in the periphery of the body -- particularly in the feet, lower legs, hands and forearms. CMT1A patients usually present with CMT symptoms during adolescence but remain ambulatory with no reduced life expectancy.

Temporary bans on fishing can be better than permanent ones as a way of allowing fish stocks in an area to recover, while still providing enough to eat, a research team has found.

A new study published in the Journal of Applied Ecology by researchers from the California Polytechnic State University San Luis Obispo (Cal Poly), WCS (Wildlife Conservation Society), Swansea University, the University of Rhode Island (URI) and other groups has revealed that the challenge of keeping fish in the sea while putting fish on the plate might be best achieved through fishing grounds with closures that are periodically subject to pulse harvests.

The new research could help revolutionize fisheries management and settle a long-running debate between fisheries management and conservation sectors about the role of marine protected areas (MPAs) in balancing potential for stock recovery and maintaining yields.

At the crux of the matter is the current model of fishing closures. Conservationists have argued that permanently closed, no-take MPAs are an effective means of mediating overfishing and allowing stock replenishment, and many global conservation agencies are thus calling on high levels of protection in 30% of the world's oceans.

However, MPAs can shift fishing effort into remaining fishing grounds. More crowded fishing grounds can make it harder to find fish, thus reducing catch efficiency and driving up costs for the industry to maintain steady yields. Therein lies a wicked tradeoff, where managers seemingly need to balance competing objectives for keeping fish in the sea and fish on the dinner plate.

The researchers considered a third management strategy that is commonly implemented by small-scale fishers across the Pacific, who periodically open their fisheries closures to pulse harvests, similar to a rotational harvest model. Like permanent no-take MPAs, these "periodic closures" temporarily displace fishing effort and thus can promote stock recovery during the intervals while they are closed.

Most importantly, however, many of the fish protected within the closure become less wary of fishing gear, giving large boosts to harvest efficiency when the closures are temporarily opened.

The researchers developed innovative bioeconomic fisheries models that incorporated this documented fish behavioral response to protection. They found that in a well-managed fishery, simulated fishing grounds with periodic closures outperformed those with non-spatial management and permanently closed MPAs for achieving the triple bottom-line objectives of simultaneously supporting high yields, stock abundance and harvest efficiency. The outcomes were maximized with closures for 1-2 year periods, followed by pulse harvests within a single year.

Lead author Paul Carvalho, formerly of CalPoly and presently at URI, says, "We were impressed by how well periodic closures continued to perform under different scenarios. Across a large range of closure durations, closure sizes, fish population growth rates and movement patterns, fishing grounds with periodic closures consistently gave the best combined outcomes for stock, yield and catch efficiency."

Dr. Fraser Januchowski-Hartley at Swansea University further explained, "While recreational and small-scale fishers across the world know that fish behavior can change because of fishing and protection, it normally isn't included in management models. These results show the importance of considering changing fish behavior and its impact on catch when designing fisheries management regimes."

In fact, the only scenarios where periodic closures did not come out on top were under extreme overfishing, where the harvest efficiency benefit was too small for the periodic closure strategy to best meet the three objectives compared with permanent no-take MPAs.

"Less than 25% of global fisheries are currently characterized by this extreme level of overfishing," explains Prof. Crow White of CalPoly. "For these fisheries, permanent no-take MPAs may be critical for any chance at stock recovery. For the remaining three-fourths, periodic closures should be considered as an option to balance conservation and sustainable development needs for the fishing sector."

These sentiments are echoed by Dr. Stacy Jupiter, WCS Melanesia Regional Director, "For many years, we have been arguing that management undertaken by small-scale fishers in the Pacific Islands is more than just a niche practice. This study validates that conclusion, and provides credence to a management tool that is incredibly important for local cultural practice. I believe these findings will have real impacts on how people around the globe implement fisheries management so that they can have their fish in the water and eat them too."

Repeat coral bleaching caused by rising sea temperatures has resulted in lasting changes to fish communities, according to a new long-term study in the Seychelles.

Large predator fish such as snappers and very small fish such as damselfish dramatically reduced in number and were largely replaced by seaweed-loving fish like rabbitfish.

Publishing in the journal Global Change Biology, researchers show clear evidence that coral bleaching back in 1998 has led to changes in biodiversity and permanent shifts in the range of fish species coexisting on coral reefs, which still remain in place today.

While some of the coral reefs surveyed, bounced back and recovered following the bleaching event, other reefs shifted to fields of seaweeds.

Changes in fish communities were most apparent on these seaweed dominated reefs, but the 'herbivore' fish that feed on seaweeds became a dominant part of the community on all the reefs in the study.

Researchers believe these same changes are likely to be found in similarly damaged reefs around the world and could be described as the 'new normal' state for post bleached reefs.

The Lancaster University-led research tracked reef recovery in the Seychelles for 16 years, before another major coral-bleaching event impacted the reefs in 2016. Despite the length of time between these two major coral bleaching events, fish populations failed to recover to their pre-bleaching condition.

Where previously there were greater numbers of large predator fish such as snappers and groupers and also a large amount of very small fish such as damselfish and butterflyfish, after bleaching a new community, dominated by algal-feeding parrotfish and rabbitfish and invertebrate-feeding fish such as emperors and wrasses, has taken over.

These changes occurred because the fish's habitat structure - corals - collapsed. Where corals did not recover and seaweeds took over the space, the number and composition of fish changed substantially.

Surprisingly, even on the reefs where the corals gradually recovered between the bleaching events, the number of fish species recovered, but did not return to their original species composition.

Other studies have shown that the time between bleaching periods is now reducing, and is typically less than 10 years. In this study the time frame from the 1998 coral bleaching event to the next major one was longer -18 years - yet the fish communities were still unable to recover. This leads researchers to conclude other reefs will suffer similar shifts, especially given bleaching events are becoming more frequent.

Dr James Robinson, of Lancaster University, the lead author of the study, said: "Although the 18-year period between major mass bleaching events allowed corals to recover on some reefs, we found evidence that fish populations were not able to return to their pre-bleaching levels, and they were substantially altered on the reefs that become dominated by seaweeds. The Seychelles case study suggests under current levels of ocean warming - where the average frequency of bleaching events is less than 10 years - permanent changes to reef fishes are likely on most coral reefs globally."

Professor Nick Graham, of Lancaster University, added: "The new normal for coral reefs will be reef fish communities which have fewer species and are dominated by herbivores and invertebrate feeding fish. This will alter the way coral reefs function, and the fishery opportunities for coastal communities adjacent to coral reefs."