Culture

Costs of care similar or lower at teaching hospitals compared to non-teaching hospitals

Boston, MA - Total costs of care are similar or somewhat lower among teaching hospitals compared to non-teaching hospitals among Medicare beneficiaries treated for common medical and surgical conditions, according to a new study led by researchers from Harvard T.H. Chan School of Public Health and Beth Israel Deaconess Medical Center.

"These findings are surprising," said senior author Ashish Jha, director of the Harvard Global Health Institute and K.T. Li professor of global health at Harvard T.H. Chan School of Public Health. "We always assumed that we had to trade-off the better outcomes at teaching hospitals with higher costs. It appears that, at least as far as Medicare is concerned, their payments for care are actually a bit less when patients go to a teaching hospital."

The study will be published June 7, 2019 in JAMA Network Open.

Teaching hospitals, which educate and train healthcare professionals, are generally considered to be more expensive than non-teaching hospitals, and some insurers and policymakers have advocated shifting care away from these institutions to lower healthcare spending for patients. However, the degree to which treatment at major teaching hospitals is associated with higher healthcare spending in general and for Medicare, the largest national payer, is not well understood.

For this study, researchers analyzed data from more than 1.2 million hospitalizations among Medicare beneficiaries age 65 and older at more than 3,000 major, minor, and non-teaching hospitals from 2014 to 2015 for some of the most common medical and surgical conditions, including pneumonia, congestive heart failure, and hip replacement. They drew from deidentified administrative Medicare claims data.

They found that major teaching hospitals had higher initial hospitalization costs than non-teaching hospitals, but that the total costs of care for the first 30 days after the hospitalization were lower at major teaching hospitals, largely due to lower costs for follow-up care and readmissions. Costs were similar at teaching and non-teaching hospitals at 90 days after hospitalization.

"These findings support the idea that to truly understand variation in health care costs, it's important to look not at just what happens in the hospital but on total spending for an acute episode," said first author Laura Burke, assistant professor of emergency medicine at Harvard Medical School and Beth Israel Deaconess Medical Center and instructor in the Department of Health Policy and Management at Harvard Chan School.

Credit: 
Harvard T.H. Chan School of Public Health

Scholars investigate how mirror activity works

A team of researchers from Germany and Russia, including Vadim Nikulin from the Higher School of Economics, have demonstrated that long contraction of muscles in one hand increases involuntary reaction of the other one. Meanwhile, the time between muscle contractions in both hands decreases. The results of the study have been published in Neuroscience.

Involuntary muscle activity of one limb during voluntary contraction of the other is called mirror activity. In other words, when a human clenches the right hand into a strong fist, the left hand's muscles react to this action with a minor involuntary activation.

It is believed that during ordinary movements that do not require significant effort the contralateral motor cortex is activated, while the other hemisphere's motor-relevant regions are in a relatively suppressed state. But with more force applied, the contralateral hemisphere's motor regions may activate the other hemisphere. This happens via the corpus callosum and induces mirror activity in the contralateral hand.

In healthy humans, mirror activity may be invisible, but is detectable with surface electromyography, which is a method used to register muscles' electrical activity. In humans with Parkinson's disease, it becomes pathologic and is called 'mirror movement'. These involuntary muscle contractions are clearly noticeable.

Previous studies of mirror activity in healthy humans have shown that as the force of one hand's contraction increases, the amplitude of the other hand's involuntary contraction grows. But it has remained unclear how mirror activity changes following repetitive contractions with constant force demands. Furthermore, another parameter of this phenomenon that has not been studied sufficiently is latency, which means the time delay between unilateral voluntary muscle activity and the contralateral involuntary muscular activity.

To analyse these indicators, a team of researchers from Germany and Russia, including Vadim Nikulin, Leading Research Fellow at the HSE Centre for Cognition & Decision Making, conducted an experiment in which participants were asked to pinch a sensor between the thumb and index finger of their right hand. The movement was performed with constant force (80% of maximum voluntary contraction) and at certain intervals. Data on the electrical activity of right and left hands' muscles were monitored with electromyography.

Analysis of the experiment's data showed that following the growing number of voluntary repetitive contractions of the right hand, the amplitude of the left hand's involuntary contractions grows, and the latency between contractions of the right and the left hand decreases. This demonstrates an inverse relation between time and amplitude.

The researchers note that growing uncontrolled motor activity may be related to participants' fatigue caused by the considerable amount of movement and effort required during the experiment. This may result in decreasing efficiency of inhibitory mechanisms involved in suppressing involuntarily occurring muscular activity.

Understanding the mechanisms of physiological mirror activity can help in developing a better understanding of the pathology of mirror movements clinically, for example, in Parkinson's disease.

Credit: 
National Research University Higher School of Economics

Diabetes can be detected in gut of cats

The cat is the only animal, aside from humans and primates, which spontaneously develops type 2 diabetes. Therefore, researchers are interested in studying how diabetes develops in cats in order to learn more about the disease in general.

Now an interdisciplinary team of researchers from the University of Copenhagen have come a step closer to understanding the disease by studying it in cats. The new study shows that the composition of gut bacteria in cats suffering from diabetes is different from the composition seen in healthy cats.

'We can tell that the diversity of gut bacteria is reduced in cats with diabetes. The same has been detected in humans, and there thus appear to be more similarities in diabetes across species than previously assumed. In fact, our results disprove another, smaller study', says PhD Student Ida Nordang Kieler from the Department of Veterinary Clinical Sciences.

Interdisciplinarity Strengthens the Results

The researchers have studied 82 cats from Denmark and Switzerland, and as there were no differences between the two populations, the results thereby relate to diabetes and not the origin or lifestyle of the cats. At the same time, they have received interdisciplinary input from researchers in other fields.

'We would not have been able to complete this study without interdisciplinary collaboration. It has really strengthened our results that we have been able to get feedback in the process and develop the study design together with experts from different fields', says Professor Charlotte Reinhard Bjørnvad from the Department of Veterinary Clinical Sciences.

The researchers have collaborated with leading researchers from the Novo Nordisk Foundation Center for Basic Metabolic Research and the Natural History Museum of Denmark. The collaboration provided the veterinary experts with valuable ideas on genetics across species as well as gut bacteria and diabetes in humans.

Bacteria Library for Cats

In the future, the researchers hope to be able to use studies like this one to better understand and treat diabetes in cats, while perhaps at the same time enhancing our knowledge of glucose metabolism and diabetes in humans. Because some uncertainties are easier to control in animal tests, Charlotte Reinhard Bjørnvad explains.

'We hope that more researchers want to collaborate on studying diabetes in cats, because in some respects these studies are easier to control than studies involving humans. You can control the nutrition of the cats meticulously and thus remove any disturbing elements and, with fewer animals, get more stable results', she elaborates.

In addition, the researchers are now trying to establish a complete library of intestinal bacteria in cats, a type of encyclopaedia for researchers studying cats. Such libraries are already available for humans and dogs. To do so they will continue to collaborate with the researchers from the Natural History Museum of Denmark.

Credit: 
University of Copenhagen - The Faculty of Health and Medical Sciences

Worm study sparks hope for slowing muscle decline

Muscle decline caused by ageing and certain diseases could be dramatically slowed by stopping a chain reaction that damages cells, new research shows.

The study revealed the previously unknown steps by which dysfunction of mitochondria - the so-called "powerhouses" of cells - harms muscle health and leads to atrophy (wasting away).

The research team, from the universities of Exeter and Nottingham (UK) and Tohoku University in Japan, showed that inhibiting various stages of this process suppressed muscle atrophy.

The research was carried out on a species of worm called Caenorhabditis elegans - recently used in a muscle study on the International Space Station because their muscle cells resemble those of humans.

"Mitochondrial dysfunction is a key feature of several muscle diseases, but treatments are currently limited," said Dr Timothy Etheridge, of the University of Exeter.

"Our research shows that mitochondrial dysfunction causes calcium to build up in cells, which in turn activates enzymes that degrade collagen.

"Collagen is vital for giving structure to the outside of cells, so degradation of collagen destabilises muscle.

"In this study, we used experimental drugs to inhibit the enzymes that degrade collagen - and the results show this suppressed muscle decline caused by dysfunctional mitochondria.

"We found the same effect in worms used to model Duchenne muscular dystrophy, which causes severe muscle weakness."

More research is needed, but the findings raise the prospect of new therapies to delay muscle atrophy caused by ageing and conditions such as Duchenne muscular dystrophy.

Credit: 
University of Exeter

Autism linked to less empathy in general population -- but that may not be a bad thing

Researchers have conclusively shown that people with autistic traits show less empathy and reduced understanding of other people's feelings in a new study out today from the University of Bath and King's College London (1000 BST Friday 7 June 2019).

Whilst autism might be associated with social difficulties, there has been debate in recent years about whether the autistic community experience difficulties in processing emotion or not and the exact form this takes.

This has centred on difficulties in measuring empathy, but also on the complicating factor that many autistic people also experience alexithymia, the condition otherwise known as 'emotional blindness'. Those with alexithymia face difficulties in understanding their own and others' emotions, yet it was less clear whether autistic people without the condition faced the same challenge.

For the new study, published in a Special Issue on Empathy in the Journal of Autism and Developmental Disorders, Dr Punit Shah, Lucy Livingston and colleagues addressed limitations in previous research. Across two large-scale surveys, sampling over 650 adults from the general population, they measured the links between autistic tendencies, alexithymia, and scored individuals on a detailed empathy test.

Their results found that having more autistic tendencies was linked to lower empathy, even after factoring in alexithymia. Using computerised simulations, in advanced statistics used for the very first time in the history of autism research, autism was the more 'dominant' and statistically important link to empathy when compared to alexithymia. These simulations showed that the results would be found around 90% of the time in the population. Their results were found in two studies and held after factoring in both participants' age and gender.

Lead researcher and expert on social processing in autism, Dr Punit Shah from Bath's Department of Psychology explains: "These findings provide some of the strongest evidence to date that autism is linked to lower empathy in the general population. Although many have associated autism with poor social skills, prior to this study the association with empathy was much less clear. By drawing on large samples and using advanced statistical techniques we hope these robust results can help settle a long-standing debate and will make an important contribution for future autism support."

Study co-author, Lucy Livingston, of the Institute of Psychiatry, Psychology & Neuroscience at King's College London, added: "Autism being linked with lower empathy is not necessarily a negative thing. Empathy is useful in social situations, but it can be a mentally tiring exercise. It is also thought that selective empathy, such as understanding some people's feelings while ignoring others', can lead to negative behaviours such as excluding some groups from society. It may be that lower empathy for those with autism actually has unforeseen benefits that we do not fully understand yet."

Bath psychology student Lois Player was also part of the research team for the study. This is the first time an undergraduate second year has co-authored a paper at Bath.

The researchers hope their results will be used to improve understanding and acceptance of people with autistic tendencies and diagnosed autism. They suggest it is important for policymakers, clinicians, and educators, to be aware of such behaviours in order to create more autism-friendly environments.

Credit: 
University of Bath

Ultrasound method restores dopaminergic pathway in brain at Parkinson's early stages

video: Focused ultrasound-induced blood-brain barrier openings in a mouse brain.

Image: 
Maria Eleni Karakatsani/Columbia Engineering

New York, NY--June 6, 2019--While there are several thousand drugs available to treat a wide range of brain diseases, from depression to schizophrenia, they cannot penetrate the blood-brain barrier (BBB) into the brain. The BBB, which protects the brain from pathogens that may be present in blood, also prevents most drugs from gaining access to the brain functional tissue, the parenchyma, a well-known challenge to the treatment of all brain diseases including neurodegenerative disorders like Parkinson's disease and Alzheimer's.

A team led by Elisa Konofagou, Robert and Margaret Hariri Professor of Biomedical Engineering and Professor of Radiology (Physics) at Columbia Engineering, has been developing a novel technique that could open up new ways to facilitate targeted drug delivery into the brain and enable drugs to treat brain diseases more focally. The researchers used transcranial, focused ultrasound and intravenously injected microbubbles into the BBB to make a localized and transient opening that allows drugs to cross through the BBB reversibly and non-invasively. Focusing on Parkinson's disease, in collaboration with Serge Przedborski's group in the department of neurology at Columbia University Irving Medical Center, they discovered that protein delivery and gene delivery across the BBB can partly restore the dopaminergic pathways, the neurons in the brain that are affected in early Parkinson's disease.

"We found both behavioral and anatomical neuronal improvements in the brain," says Konofagou, who led the study, published online on April 4 by the Journal of Controlled Release, and in print June 10. "This is the first time that anyone has been able to restore a dopaminergic pathway with available drugs at the early stages of Parkinson's disease. We were able to curb the rapid progression of neurodegeneration while improving the neuronal function. We expect our study will open new therapeutic avenues for the early treatment of central nervous system diseases."

The team targeted the brain regions involved in early stage Parkinson's and Alzheimer's disease, such as the putamen and hippocampus. The tool they developed for the study is a device that uses a neuronavigation system to direct the treatment in real-time. The U.S. FDA has just assigned the team an Investigational Device Exemption (IDE) to use the device in clinical trials to test its safety in Alzheimer's patients.

"Neurosurgeons use such systems all the time to guide them for neurosurgery," says Antonios Pouliopoulos, associate research scientist in Konofagou's lab who worked on the development of the clinical neuronavigation system. "Our group just replaced the surgical instrument with an ultrasound transducer to perform our non-invasive procedure."

Konofagou's Ultrasound Elasticity and Imaging Laboratory is the only academic lab in the U.S. to receive FDA approval for ultrasound-assisted, blood-brain-barrier opening. Other groups doing similar research either use nanoparticles to facilitate drug delivery or require MRI to guide the procedure. Konofagou's approach is MRI-independent and does not require any nanoparticles.

Her device is a single-element transducer that is much smaller, faster, and less expensive than current helmet-shaped, 1024-element transducer systems that use MRI guidance. Because Konofagou's system is portable, doctors will be able to treat patients anywhere in a hospital and, in the future, even at a patient's home. Treatment can be completed in less than 30 minutes, compared to three to four hours for MRI-guided therapy, and monitored in real-time, a unique feature of the new device. The cost is 10 times less than the MRI-guided helmet. The first trial with the device will be with Alzheimer's patients, after which Konofagou plans to work with Parkinson's patients.

Konafagou recently won a four-year $2.5M NIH grant to use a similar device for deep brain stimulation aiming to unveil the mechanism by which ultrasound excites neurons and to monitor the unveiled mechanism in human subjects. In addition, she will be honored with the 2019 Engineering in Medicine and Biology Society's Technical Achievement Award in Berlin this July for her "outstanding and pioneering contributions in the field of ultrasound imaging and therapy, and their application and clinical translation to the diagnosis of cardiovascular diseases, tumor diagnosis and treatment as well as brain drug delivery and stimulation."

"We all have loved ones with neurodegenerative disorders," Konofagou adds. "My grandmother has been suffering from dementia for more than five years, so I know first-hand how essential it would be to have a simple device that can be wheeled into the patient's home and offer a higher quality of life, especially for our rapidly aging population. And there are so many deadly diseases like brain tumors that affect people of all ages, with no cure yet in sight. That's why we want to bring our research so rapidly to the clinic."

Credit: 
Columbia University School of Engineering and Applied Science

How artificial intelligence detects rare diseases

image: The neural network combines data from portrait images with gene and patient data.

Image: 
© Foto: Tori Pantel

Every year, around half a million children worldwide are born with a rare hereditary disease. Obtaining a definitive diagnosis can be difficult and time consuming. In a study of 679 patients with 105 different rare diseases, scientists from the University of Bonn and the Charité - Universitätsmedizin Berlin have shown that artificial intelligence can be used to diagnose rare diseases more efficiently and reliably. A neural network automatically combines portrait photos with genetic and patient data. The results are now presented in the journal "Genetics in Medicine".

Many patients with rare diseases go through lengthy trials and tribulations until they are correctly diagnosed. "This results in a loss of valuable time that is actually needed for early therapy in order to avert progressive damage," explains Prof. Dr. med. Dipl. Phys. Peter Krawitz from the Institute for Genomic Statistics and Bioinformatics at the University Hospital Bonn (UKB). Together with an international team of researchers, he demonstrates how artificial intelligence can be used to make comparatively quick and reliable diagnoses in facial analysis.

The researchers used data of 679 patients with 105 different diseases caused by the change in a single gene. These include, for example, mucopolysaccharidosis (MPS), which leads to bone deformation, learning difficulties and stunted growth. Mabry syndrome also results in intellectual disability. All these diseases have in common that the facial features of those affected show abnormalities. This is particularly characteristic, for example, of Kabuki syndrome, which is reminiscent of the make-up of a traditional Japanese form of theatre. The eyebrows are arched, the eye-distance is wide and the spaces between the eyelids are long.

The used software can automatically detect these characteristic features from a photo. Together with the clinical symptoms of the patients and genetic data, it is possible to calculate with high accuracy which disease is most likely to be involved. The AI and digital health company FDNA has developed the neural network DeepGestalt, which the researchers use as a tool of artificial intelligence for their study. "PEDIA is a unique example of next-generation phenotyping technologies," said Dekel Gelbman, CEO of FDNA. "Integrating an advanced AI and facial analysis framework such as DeepGestalt into the variant analysis workflow will result in a new paradigm for superior genetic testing".

Researchers train the neural network with 30,000 images

The scientists trained this computer program with around 30,000 portrait pictures of people affected by rare syndromal diseases. "In combination with facial analysis, it is possible to filter out the decisive genetic factors and prioritize genes," says Krawitz. "Merging data in the neuronal network reduces data analysis time and leads to a higher rate of diagnosis."

The head of the Institute of Genomic Statistics and Bioinformatics at the UKB has been working with FDNA for some time. "This is of great scientific interest to us and also enables us to find a cause in some unsolved cases," said Krawitz. Many patients are currently still looking for an explanation for their symptoms.

The study is a team effort between computer science and medicine. This can also be seen in the shared first authorship of the computer scientist Tzung-Chien Hsieh, doctoral student at the institute of Professor Krawitz, and Dr. Martin Atta Mensah, physician at the Institute of Medical Genetics and Human Genetics of the Charité and Fellow of the Clinician Scientist Program of the Charité and Berlin Institute of Health (BIH). Prof. Dr. Stefan Mundlos, Director of the Institute of Medical Genetics and Human Genetics at the Charité, also participated in the study, as did over 90 other scientists.

"Patients want a prompt and accurate diagnosis. Artificial intelligence supports physicians and scientists in shortening the journey," says Dr. Christine Mundlos, Deputy Managing Director of the alliance of patients with chronic rare diseases (ACHSE) e.V. "This also improves the quality of life of those affected to some extent."

Credit: 
University of Bonn

Could you fail a drug test by taking Cannabidiol (CBD)?

image: Cannabidiol, or CBD, is a non-psychoactive compound produced by the marijuana plant that seems to be everywhere these days. Interestingly, the chemical structure of CBD is very similar to THC, which is the marijuana-derived compound responsible for getting people high and the one screened for by drug tests. This structural similarity begs the question: Could using CBD make you fail a drug test? In this episode of Reactions, we break down the chemistry behind the possibilities: https://youtu.be/BzmZ_sb5dZk.

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The American Chemical Society

WASHINGTON, June 6, 2019 -- Cannabidiol, or CBD, is a non-psychoactive compound produced by the marijuana plant that seems to be everywhere these days. Maybe you've even been asked if you'd like it added to your morning cup of joe! Interestingly, the chemical structure of CBD is very similar to THC, which is the marijuana-derived compound responsible for getting people high and the one screened for by drug tests. This structural similarity begs the question: Could using CBD make you fail a drug test? In this episode of Reactions, we break down the chemistry behind the possibilities: https://youtu.be/BzmZ_sb5dZk.

Credit: 
American Chemical Society

Researchers develop fast, efficient way to build amino acid chains

image: A team including, from left, postdoctoral researcher Ziyuan Song, professor Jianjun Cheng and graduate students Tianrui Xue and Lazaro Pacheco, developed a new method that streamlines the construction of amino acid building blocks that can be used in a multitude of industrial and pharmaceutical applications.

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Photo by L. Brian Stauffer

CHAMPAIGN, Ill. -- Scientists often build new protein molecules by stringing groups of amino acids together. These amino acid chains, called polypeptides, are the building blocks needed in drug development and the creation of new biomaterials.

The process for building polypeptides is difficult, however. Researchers report that they have developed a faster, easier and cheaper method for making new polypeptides than was previously available. The new approach uses a streamlined process that purifies the amino acid precursors and builds the polypeptides at the same time, unlike previous methods in which the processes were separate, laborious and time-consuming.

Traditionally, making polypeptide chains has been a very complicated process, said University of Illinois materials science and engineering professor Jianjun Cheng, who led the new research. Synthesizing and purifying the amino acid precursors, namely N-carboxyanhydride, or NCA, requires days of tedious effort, and building the polypeptide chains takes hours to days, he said.

"The field has never grown big, in part because synthesizing polypeptides is so complicated," Cheng said. "NCA has a lot of impurities that are difficult to remove. Until now, the synthesis of high-quality polypeptides required ultrapure NCAs."

In biological cells, enzymes called ribozymes join amino acids together to form proteins, Cheng said. This process takes place in the presence of water, salt and numerous other molecules. Replicating this process in the laboratory is very difficult, however. Current methods require researchers to use purified NCA molecules and to build the chains in a water-free environment.

Cheng and his colleagues drew inspiration from ribozymes, which excel at making amino acid chains quickly while isolating them from the cellular environment. The team developed a system that mimics the ribozyme function, building the amino acid chains quickly while removing any molecules that could contaminate the system. This allows the researchers to build the desired chains with NCAs that are not pure.

"This is the first time since the discovery of the NCA molecule in 1906 that we have been able to build long chains using non-purified NCA," Cheng said.

"I worked on NCA purification for several years and found it very painful, because the process required water-free conditions and was technically challenging," said postdoctoral researcher Ziyuan Song, a member of Cheng's lab. "That's why there aren't many research groups working in this field. With this method, we can get more people to join and find more applications."

The method can be used in chemistry, biology and industry, where protein chains are routinely used as building blocks for the assembly of useful molecules, the researcher said.

"Previously, the field required specialized chemists like us to make these building blocks," Cheng said. "Our new protocol allows anyone with basic chemistry skills to build the desired polypeptides in a few hours."

The researchers are investigating how to scale up the process and explore the full range of chemical and biological applications the new approach allows.

The researchers report their findings in the Proceedings of the National Academy of Sciences.

Credit: 
University of Illinois at Urbana-Champaign, News Bureau

I, you, or we: Pronouns provide hints to romantic attachment styles

Sometimes people wish they had greater insight into how their partner really feels. Recent work in social and personality psychology dives into the stories people tell about their romantic relationships, and finds that those prone to avoidant attachment, are less likely to use the word "we" when talking about these relationships.

The results appear in the journal Social Psychological and Personality Science.

"The pronouns individuals use when narrating their previous experiences from within their romantic lives provide a clue as to their corresponding attachment styles," says Will Dunlop (University of California, Riverside), lead author of the research.

Typically, attachment styles are represented by two factors - anxiety (reflecting the degree to which an individual is preoccupied with, and fears losing, his or her romantic partner) and avoidance (reflecting the degree to which an individual feels uncomfortable getting close to, and depending upon, his or her partner).

Dunlop and colleagues reviewed over 1400 observations drawn from seven studies, and then explored relations between adult romantic attachment styles and pronoun use.

They found that both anxious and avoidant attachment styles correlated positively with I-talk and negatively with we-talk, but once they accounted for participants' demographics and personality traits, the correlation for anxious attachment and pronoun use was no longer significant. But for avoidant attachment types, the lack of the use of "we" talk held strong.

Dunlop suggests that the way individuals describe their romantic experiences could offer insights into how that person might behave and interact in romantic relationships as well.

"Anxious and avoidant attachment styles capture individual differences in the ways people think, feel, and behave in romantic relationships. Given that those with higher levels of avoidant attachment were found to demonstrate lower levels of we-talk when describing experiences from their romantic lives, considering the use of we words (e.g., us, ours) in the disclosure of previous romantic experiences may offer indication of one's avoidant tendencies. This is a relatively novel and indirect way of gauging avoidant attachment, as individuals are typically unaware of the pronouns they use."

For future research, Dunlop is curious as to the clues narratives from other domains (e.g., one's professional life) may offer for attachment and other markers of adjustment. He also wonders what link, if any, there may be between the pronoun use and people's overall love life satisfaction.

Credit: 
Society for Personality and Social Psychology

Nuclear architecture: What organizes the genome in the nucleus?

Spatial separation of active from inactive fractions of the genome in the cell nucleus is crucial for gene expression control. A new study uncovers leading mechanisms of such separation and turns our picture of the nucleus upside down.

Eukaryotic chromosomes are built of chromatin, a complex of DNA and associated proteins. Depending on transcriptional activity and degree of compaction, two types of chromatin can be distinguished and these two types are spatially separated within the nucleus. The highly condensed fraction is made up of regions of chromatin that contain few genes and is transcriptionally inactive. It is called heterochromatin, and is located in the periphery of the nucleus, close to the nuclear membrane. Euchromatin, on the other hand, is enriched in genes and corresponds to the active fraction of the genome. It occupies the inner regions of the nucleus, is less densely packed, and therefore more accessible to the protein machineries required for gene expression. This general pattern of genome organization is found in virtually all eukaryotic cell types, but the mechanisms establishing the characteristic distribution remain poorly understood. Research carried out by a team led by Irina Solovei at Ludwig-Maximilians-Universitaet (LMU) in Munich's Biocenter, in cooperation with Job Dekker (University of Massachusetts Medical School) and physicists from the group of Leonid Mirny at MIT (Institute for Medical Engineering and Science) now suggests that the driving force in chromatin segregation is the inactive heterochromatin and that in the 'default' chromatin distribution of euchromatin and heterochromatin are reversed. The new findings appear in the leading journal Nature.

Many mechanisms have been proposed to explain how chromatin is segregated within the nucleus, however none of them were conclusive, largely, because it is difficult to analyze the interactions of the two chromatin types in the context of conventional nuclei with heterochromatin tethered to the nuclear membrane. "For our study, we therefore chose so called inverted cell nuclei," says Solovei. She and her Munich colleagues discovered these nuclei about 10 years ago in the retina of nocturnally active mammals, where they are restricted to the type of photoreceptor cells known as rods. In rods, the tightly condensed heterochromatin is packed in the interior of the nuclei, while the active euchromatin is localized directly under the nuclear membrane - a unique exception to the general rule. It turned out that the heterochromatin core of rod nuclei serves as a microlens condensing light and thus improving optical properties in the nocturnal retinas. Subsequent study from the same group disclosed the mechanism of inversion by revealing that these atypical nuclei lack two protein complexes that normally link the heterochromatin to the inner surface of the nuclear membrane, the nuclear lamina.

Using data obtained by a combination of modern microscopy and molecular biology techniques, the researchers have now generated polymer models of the individual chromosomes and of entire nuclei. By simulating the behavior of these polymers under different conditions, they were able to investigate the role of interactions within and between the two chromatin fractions and the nuclear lamina. These studies showed that interactions between heterochromatic regions alone are sufficient for chromatin segregation, whereas interactions within euchromatin are dispensable for this process. "Our results indicate that the inverted nucleus conceptually represents the default nuclear architecture," says Mirny; "while interactions of heterochromatin with the nuclear lamina are essential for building the conventional architecture". "In this respect," says Solovei, "it is intriguing to ask why the majority of eukaryotes have conventional nuclei, and what the functional relevance of heterochromatin positioning at the nuclear periphery might be."

Credit: 
Ludwig-Maximilians-Universität München

Fussy, hungry, or even in pain? Scientists create an AI tool to tell babies' cries apart

Every parent knows the frustration of responding to a baby's cries, wondering if it is hungry, wet, tired, in need of a hug, or perhaps even in pain. A group of researchers in USA has devised a new artificial intelligence method that can identify and distinguish between normal cry signals and abnormal ones, such as those resulting from an underlying illness. The method, based on a cry language recognition algorithm, promises to be useful to parents at home as well as in healthcare settings, as doctors may use it to discern cries among sick children.

The research was published in the May issue of IEEE/CAA Journal of Automatica Sinica (JAS), a joint publication of the IEEE and the Chinese Association of Automation.

Experienced health care workers and seasoned parents are able to pretty accurately distinguish among a baby's many needs based on the crying sounds it makes. While each baby's cry is unique, they share some common features when they result from the same reasons. Identifying the hidden patterns in the cry signal has been a major challenge, and artificial intelligence applications have now been shown to be an appropriate solution within this context.

The new research uses a specific algorithm based on automatic speech recognition to detect and recognize the features of infant cries. In order to analyze and classify those signals, the team used compressed sensing as a way to process big data more efficiently. Compressed sensing is a process that reconstructs a signal based on sparse data and is especially useful when sounds are recorded in noisy environments, which is where baby cries typically take place. In this study, the researchers designed a new cry language recognition algorithm which can distinguish the meanings of both normal and abnormal cry signals in a noisy environment. The algorithm is independent of the individual crier, meaning that it can be used in a broader sense in practical scenarios as a way to recognize and classify various cry features and better understand why babies are crying and how urgent the cries are.

"Like a special language, there are lots of health-related information in various cry sounds. The differences between sound signals actually carry the information. These differences are represented by different features of the cry signals. To recognize and leverage the information, we have to extract the features and then obtain the information in it," says Lichuan Liu, corresponding author and Associate Professor of Electrical Engineering and the Director of Digital Signal Processing Laboratory whose group conducted the research.

The researchers hope that the findings of their study could be applicable to several other medical care circumstances in which decision making relies heavily on experience. "The ultimate goals are healthier babies and less pressure on parents and care givers," says Liu. "We are looking into collaborations with hospitals and medical research centers, to obtain more data and requirement scenario input, and hopefully we could have some products for clinical practice," she adds.

Credit: 
Chinese Association of Automation

Jack of all trades or master of none? Impact of specialization on returns

image: Does specialization have implications for investors' wealth.

Image: 
Pixabay (Creative Commons)

A new study has found that specialist active management firms outperform those that have a more mixed offering of active and passive products, with the benefit of specialisation being 0.7 per cent a year on average.

It is the first study to explore the impact of specialisation and is published this month in the journal International Review of Financial Analysis.

Using a sample of more than 2100 fund families internationally, and more than 20 years of data, the study led by Dr Lorenzo Casavecchia of UTS Business School found that funds with a greater percentage of total assets under active management outperformed those less concentrated on active management.

The outperformance was 70 basis points a year, on average, before fees. This excess return is economically significant considering that it is risk adjusted.

A "fund family" is a group of funds under the banner of one brand - for example, an investment management house like Fidelity, Vanguard, BlackRock, or Legg Mason. Fund families diversify across active and passive management to a remarkable extent, Dr Casavecchia explains. Even a business like Vanguard that's known as an "index manager" has actively managed funds within its family of products.

Some fund families like to diversify more than others across active and passive to minimise redemption risk at times of market disturbance - when investors might flee certain types of funds - or to maximise fee revenue, he says. On the other hand, fund families like US-based T.Rowe Price pride themselves on having a high degree of specialisation. In the study period it had 94 per cent of fund assets under active management.

"The question for us - and for investors - is whether specialisation has implications for investors' wealth," says Dr Casavecchia, a researcher with the Finance discipline group in the Business School.

The study found that active specialisation of the fund family does generate value and, investigating where that value comes from, points to a robust association with "manager skill" at the fund family level.

"Our study shows that fund families with greater asset-based focus on the active segment are more likely to possess better managerial skills at running their active funds," says the paper, co-authored with Macquarie University PhD candidate Georgina Ge.

That is derived in part from the expertise that comes from specialising, from the size of their research infrastructure, and from the resources dedicated to private information production.
"These fund families were significantly less likely to rely on public information," says Dr Casavecchia.

The findings were supported by an experiment where the researchers looked at what happened to funds that were sold, intact, out of a more actively-focused fund family into a less specialised one. After the move, such funds slipped in performance. The converse was also true.

This is not an "active versus passive" study, Dr Casavecchia notes, and it is not about the impact of fees.

But for those investors who have already decided they want to be in the active sector, it suggests they are better off seeking out true-to-label, focused active management specialists.

"The findings highlight the significant performance drag experienced by an average equity fund investor if the operational scope and investment philosophy of their fund family isn't aligned with the primary objective of active funds - to outperform the index," the paper says.

Investors should also diversify by using a range of actively-focused specialists, rather than sticking with just one brand, Dr Casavecchia adds. That's because the study found the dark side of specialisation is greater exposure to losses in periods of severe market stress.

The study involved 2137 fund families, over the period from 1993 to 2015. The source data was from the US because of the greater detail available there, but Dr Casavecchia says the findings would apply in Australia.

Credit: 
University of Technology Sydney

Heart rate variation due to stress affects auditory attention

image: Study shows that brain activity related to auditory perception parallels heart rate, offering new perspectives for the treatment of attention and communication disorders.

Image: 
Viviane B. de Góes

Sudden hearing loss can be experienced in highly stressful situations, usually lasting a short time. Researchers at São Paulo State University (UNESP) in Brazil, collaborating with colleagues at Oxford Brookes University in the United Kingdom, have reported a discovery that contributes to a deeper understanding of this phenomenon.

According to a study by the group published in Scientific Reports, brain activity related to auditory attention keeps pace with heart rate. Stress-induced changes in heart rate may therefore impair auditory perception. This finding offers new perspectives for the treatment of attention and communication disorders.

The study was supported by São Paulo Research Foundation - FAPESP. Brazilian scientists affiliated with the University of São Paulo (USP) and ABC Medical School (FMABC) also took part.

"We found that even quite low levels of stress can affect heart rate and impair auditory attention," Vitor Engrácia Valenti told.

According to Valenti, a professor at the UNESP campus in Marília and principal investigator for the study, recent research had already shown that heart rate can fluctuate in response to auditory stimulation and that these variations are controlled by the vagus nerve.

"However, exactly how auditory stimuli influence heart rate control by the vagus nerve was poorly understood," Valenti said. "In addition, it wasn't clear whether heart rate control interacted with the cortical brain activity associated with auditory attention in humans."

The vagus nerve extends from the brainstem down to the abdomen and is part of the autonomic nervous system that controls unconscious bodily processes such as heart rhythm, breathing and digestion. An overactive vagus nerve can result in an abnormally low heart rate.

Previous studies with animals showed that vagal activity increases during relaxing auditory stimulation and boosts the expression of a protein called c-Fos in the auditory cortex. These findings pointed to an association between cortical sound processing and the parasympathetic nervous system, Valenti explained.

The researchers set out to investigate these interactions by means of an experiment with 49 women in which heart rate regulation was challenged by a mildly stressful language test.

The participants were asked to say as many Portuguese words beginning with 'A' as they could in 60 seconds, without repetition or inflections such as the diminutive.

The time limit was considered necessary to avoid interference in the volunteers' brain activity either by the sympathetic nervous system - which regulates responses to stress, such as heart rate acceleration via the effects of adrenaline - or the release of cortisol.

Heart rate and auditory processing were measured before and after the language test. The integrity of the auditory pathway in the brain was verified electrophysiologically using a standard procedure called long-latency auditory evoked potential (P300).

Heart rate variability is an indicator of autonomic cardiac control in response to different levels of stress. The P300 test was used in this study to analyze auditory attention to a sound stimulus by monitoring the prefrontal cortex and auditory cortex activity via electrodes placed on the forehead, cranial vertex and earlobes.

The results of the tests showed that the relatively mild stress to which the volunteers were subjected was sufficient to alter their heart rate and that this happened in parallel with an attenuation of their auditory attention.

Statistical analyses, including correlations and linear regression models, indicated a weak but significant association between autonomic control of the heart by the vagus nerve and auditory processing in the brain.

"This suggests that auditory information is processed less well in stressful than calm situations," Valenti said.

"It's possible that if you breathe more slowly under stress, for example, the parasympathetic nervous system may slow your heart rate and improve your auditory perception."

According to Valenti, the findings suggest novel possibilities for the treatment of patients with attention and communication disorders based on vagus nerve activation by electrical stimulation in the auricular region to control heart rate.

Studies of autistic children conducted by researchers at UNESP Marília's Phonoaudiology Department have used this method and achieved promising results.

"The data from these studies shows a significant improvement in the symptoms of children with autism as a result of this treatment method," Valenti said.

Credit: 
Fundação de Amparo à Pesquisa do Estado de São Paulo

Global study links better education, wealth to improved heart health

Findings from a sweeping global study conducted by SFU Health Sciences professor Scott Lear, among others, reveal a direct correlation between socioeconomic status and one's susceptibility to heart attacks and strokes.

Lear, who holds the Pfizer/Heart & Stroke Foundation Chair in Cardiovascular Prevention Research at St. Paul's Hospital, is the principal investigator of the Prospective Urban Rural Epidemiology (PURE) study site in Vancouver. The latest findings of the study have been published in leading international health journal The Lancet: Global Health.

Researchers carried out the wide-ranging and ongoing study over a period of more than 15 years in 25 countries and based their findings on data collected from over 225,000 participants in countries as diverse as Tanzania, Zimbabwe, Bangladesh, India, Malaysia, Argentina, Brazil, Saudi Arabia. Iran, Canada and Sweden, to name a few.

Data was collected from families and households through two questionnaires. A third questionnaire was used to collect data on cardiovascular risk factors, which also included a physical examination. Socioeconomic status was assessed using education and a household wealth index as the main determinants.

While the study initially focused on wealth as the main indicator for predicting heart health, researchers soon found that it could not be used as a standardized measure. But education levels could.

"How much money you have tends to be a strong predictor of health outcomes, but education seems to be a far more robust measure to use across countries," Lear says.

"With education being such a strong indicator or determinant of health, education is actually what we consider a modifiable factor, whereas wealth is not as modifiable. If we give people money they don't suddenly become healthy, but if we strive to better educate our population, that will result in improved health because there is a more direct link between education and health outcomes."

He adds that the study's strength also lies in its range and variability achieved from different geographical settings.

"We have countries with varying types of healthcare services and we can identify what works and what doesn't... one of the unique aspects (of the study) is bringing together countries from all over the world that have a range of development.

"That allows us to look at factors that would vary to a greater extent than they would if we just looked exclusively at western countries."

This latest installment in papers published under the PURE study is a result of extensive research conducted by an international team of scientists, who recruited participants aged between 35 and 70 years in both urban and rural communities.

The PURE study is similar in scale to other cohort studies, such as the Framingham heart study or the Harvard Alumni study, where the participants' health is tracked over a long period of time.

Credit: 
Simon Fraser University