In a new study, UC San Francisco scientists used maps of brain connections to predict how brain atrophy would spread in individual patients with frontotemporal dementia (FTD), adding to growing evidence that the loss of brain cells associated with dementia spreads via the synaptic connections between established brain networks. The results advance scientists' knowledge of how neurodegeneration spreads and could lead to new clinical tools to evaluate how well novel treatments slow or block the predicted trajectory of these diseases.
"Knowing how dementia spreads opens a window onto the biological mechanisms of the disease -- what parts of our cells or neural circuits are most vulnerable," said study lead author Jesse Brown, PhD, an assistant professor of neurology at the UCSF Memory and Aging Center and UCSF Weill Institute for Neurosciences. "You can't really design a treatment until you know what you're treating."
FTD, the most common form of dementia in people under the age of 60, comprises a group of neurodegenerative conditions with diverse linguistic and behavioral symptoms. As in Alzheimer's disease, the diversity of FTD symptoms reflects significant differences in how the neurodegenerative disease spreads through patients' brains. This variability makes it difficult for scientists searching for cures to pin down the biological drivers of brain atrophy and for clinical trials to evaluate whether a novel treatment is making a difference in the progression of a patient's disease.
Previous research by the study's senior author, William Seeley, MD, a professor of neurology and pathology at the Memory and Aging Center and Weill Institute, set off a sea change in dementia research by showing that patterns of brain atrophy in many forms of dementia map closely onto well-known brain networks -- groups of functionally related brain regions that work cooperatively via their synaptic connections, sometimes over long distances. In other words, Seeley's work proposed that neurodegenerative diseases don't spread evenly in all directions like a tumor, but can jump from one part of the brain to another along the anatomical circuits that wire these networks together.
In their new study -- published October 14 in Neuron -- Brown, Seeley and colleagues provided further evidence supporting this idea by examining how well neural network maps based on brain scans in healthy individuals could predict the spread of brain atrophy in FTD patients over the course of a year.
The researchers recruited 42 patients at the UCSF Memory and Aging Center with behavioral variant fronto-temporal dementia (bvFTD), a form of FTD that causes patients to exhibit inappropriate social behaviors, and 30 patients with semantic variant primary progressive aphasia (svPPA), a form of FTD that mainly impacts patients' language abilities. In their first visits to UCSF, each of these patients underwent a "baseline" MRI scan to assess the extent of existing brain degeneration and then had a follow-up scan about a year later to measure how their disease had progressed.
The researchers first estimated where the brain atrophy seen in each patient's baseline scans had begun, based on the hypothesis that brain degeneration begins in some particularly vulnerable location, then spreads out to anatomically connected brain regions. To do this, the researchers built standardized maps of the main functional partners of 175 different brain regions based on functional MRI (fMRI) scans of 75 healthy adults. They then identified which of these networks best matched the pattern of brain atrophy seen in a given FTD patient's baseline brain scans, and defined that network's central hub as the likely epicenter of the patient's degeneration.
They then used the same standardized connectivity maps to predict where the patient's brain atrophy was most likely to have spread in the follow-up scans done one year later, and compared the accuracy of these predictions to others that didn't take functional network connectivity into account.
They found that two particular connectivity measures significantly improved their predictions of a given brain region's chances of developing brain atrophy between the baseline and follow-up brain scans. One, called "shortest path to the epicenter," captured the number of synaptic "steps" that region was from the estimated disease epicenter -- essentially the number of links in the neural chain connecting the two areas -- while the other, called "nodal hazard," represented how many regions connected to a given region were already experiencing significant atrophy.
"It's like with an infectious disease, where your chances of becoming infected can be predicted by how many degrees of separation you have from 'Patient Zero' but also by how many people in your immediate social network are already sick," Brown said.
The researchers showed that on average these two measures of network connectivity did better at predicting the spread of disease to a new brain region than its simple straight-line distance from a patient's existing atrophy. In many cases the disease completely bypassed brain areas that were adjacent but not anatomically connected to already-atrophied regions, instead jumping to more functionally linked regions.
Although this method shows great promise, the researchers emphasize that it is not yet ready for clinical use. They hope to improve the accuracy of their predictions by -- among other approaches -- using individualized network maps for each patient rather than using average connectivity maps, and by developing more specialized prediction models for particular subtypes of FTD.
In addition to the biological insights the discovery provides about the mechanisms of spreading brain atrophy in FTD, which will inform ongoing efforts to develop treatments, the researchers also hope the findings will lead to improved metrics for evaluating therapies already entering clinical trials -- for instance by giving trial scientists early insights into whether the treatment is altering a predicted course of disease progression. Researchers could also use better predictions of how atrophy will spread through the brain to help prepare patients and their families for the symptoms they are likely to experience as their disease progresses.
"We are excited about this result because it represents an important first step toward a more precision medicine type of approach to predicting progression and measuring treatment effects in neurodegenerative disease," Seeley said.
In the future, Brown said, scientists might be able to develop therapies that specifically target the likely next site of disease and perhaps prevent atrophy from spreading from one region to another.
Read more at Science Daily
Oct 14, 2019
Scientists help immune system find hidden cancer cells
Cancer cells are masters at avoiding detection, but a new system developed by Yale scientists can make them stand out from the crowd and help the immune system spot and eliminate tumors that other forms of immunotherapies might miss, the researchers report Oct. 14 in the journal Nature Immunology.
The new system reduced or eliminated melanoma and triple-negative breast and pancreatic tumors in mice, even those located far from the primary tumor source, the researchers report.
"This is an entirely new form of immunotherapy," said Sidi Chen, assistant professor of genetics and senior author of the study.
Immunotherapy has revolutionized the treatment of cancer but existing therapies don't work on all patients or not at all against some cancers. Existing therapies sometimes fail to recognize all molecular disguises of cancer cells, rendering them less effective.
To address those shortcomings, Chen's lab developed a new system that weds viral gene therapy and CRISPR gene-editing technology. Instead of finding and editing pieces of DNA and inserting new genes, the new system -- called Multiplexed Activation of Endogenous Genes as Immunotherapy (MAEGI) -- launches a massive hunt of tens of thousands of cancer-related genes and then acts like a GPS to mark their location and amplify the signals.
MAEGI marks the tumor cells for immune destruction, which turns a cold tumor (lacking immune cells) into a hot tumor (with immune cells). It is the molecular equivalent of dressing tumor cells in orange jump suits, allowing the immune system police to quickly find and eradicate the deadly cells, Chen said.
"And once those cells are identified, the immune system immediately recognizes them if they show up in the future," Chen said.
The new system in theory should be effective against many cancer types, including those currently resistant to immunotherapy, he said.
Upcoming studies will optimize the system for simpler manufacturing and prepare for clinical trials in cancer patients.
From Science Daily
The new system reduced or eliminated melanoma and triple-negative breast and pancreatic tumors in mice, even those located far from the primary tumor source, the researchers report.
"This is an entirely new form of immunotherapy," said Sidi Chen, assistant professor of genetics and senior author of the study.
Immunotherapy has revolutionized the treatment of cancer but existing therapies don't work on all patients or not at all against some cancers. Existing therapies sometimes fail to recognize all molecular disguises of cancer cells, rendering them less effective.
To address those shortcomings, Chen's lab developed a new system that weds viral gene therapy and CRISPR gene-editing technology. Instead of finding and editing pieces of DNA and inserting new genes, the new system -- called Multiplexed Activation of Endogenous Genes as Immunotherapy (MAEGI) -- launches a massive hunt of tens of thousands of cancer-related genes and then acts like a GPS to mark their location and amplify the signals.
MAEGI marks the tumor cells for immune destruction, which turns a cold tumor (lacking immune cells) into a hot tumor (with immune cells). It is the molecular equivalent of dressing tumor cells in orange jump suits, allowing the immune system police to quickly find and eradicate the deadly cells, Chen said.
"And once those cells are identified, the immune system immediately recognizes them if they show up in the future," Chen said.
The new system in theory should be effective against many cancer types, including those currently resistant to immunotherapy, he said.
Upcoming studies will optimize the system for simpler manufacturing and prepare for clinical trials in cancer patients.
From Science Daily
Oct 13, 2019
Archaeology: Social inequality in Bronze Age households
Archaeogenetic analyses provide new insights into social inequality 4000 years ago: nuclear families lived together with foreign women and individuals from lower social classes in the same household.
Social inequality already existed in southern Germany 4000 years ago, even within one household, a new study published in the journal Science finds. Archaeological and archaeogenetic analyses of Bronze Age cemeteries in the Lech Valley, near Augsburg, show that families of biologically related persons with higher status lived together with unrelated women who came from afar and also had a high status, according to their grave goods. In addition, a larger number of local but clearly less well-off individuals were found in the same cemeteries, which were small gravesites associated with single homesteads. The researchers conclude that social inequality was already part of households structures in that time and region. Whether the less well-off individuals were servants or slaves can only be speculated upon.
In Central Europe, the Bronze Age covers the period from 2200 to 800 BCE. At that time people acquired the ability to cast bronze. This knowledge led to an early globalization, since the raw materials had to be transported across Europe. In an earlier study, the current team had shown that, 4000 years ago, the majority of women in the Lech Valley came from abroad and may have played a decisive role in the transfer of knowledge. Supraregional networks were apparently fostered by marriages and institutionalized forms of mobility.
The current archaeological-scientific project was situated at the Heidelberg Academy of Sciences and led by Philipp Stockhammer from the Ludwig-Maximilians-Universitaet (LMU) in Munich together with Johannes Krause and Alissa Mittnik from the Max Planck Institute for the Science of Human History in Jena and the University of Tübingen. The researchers attempted to investigate the effects of this mobility and other concurrent changes. The excavations south of Augsburg, which took place at the sites of Bronze Age homestead farms and their associated graveyards, enabled archaeologists to zoom into the Bronze Age in unprecedented resolution in order to investigate how the transition from the Stone Age to the Bronze Age affected the households of that time. "Wealth was correlated with either biological kinship or foreign origin. The nuclear family passed on their property and status over generations. But at every farm we also found poorly equipped people of local origin," says Philipp Stockhammer, Professor of Prehistoric Archaeology at LMU Munich. This finding suggests a complex social structure of households, as is also known from Classical Greece and Rome. In Roman times, slaves were also part of the family unit, but had a different social status. However, these people in the Lech Valley lived over 1500 years earlier. "This shows how long the history of social inequality in family structures goes back in time," Stockhammer continues.
Stable social structures over 700 years
It was already known that the first larger hierarchical social structures evolved in the Bronze Age. The findings of the current study were surprising in that social differences existed within a single household and were maintained over generations.
Grave goods can reveal the social status of the deceased to archaeologists. In the Lech Valley, weapons and elaborate jewelry were only found in the graves of closely related family members and women who came into the family from long distances, up to several hundred kilometers away. Other unrelated individuals of local origin were found in the same cemeteries without such high-status grave goods.
This study also succeeded in reconstructing for the first time family trees from prehistoric cemeteries spanning four to five generations. Surprisingly, however, these only included the male lineages. The female descendants apparently left the farms where they reached adulthood. The mothers of the sons, on the other hand, were all women who had moved in from afar. "Archaeogenetics provides us with a completely new view of the past. Until recently, we would not have thought it possible to examine marriage rules, social structure and social inequality in prehistory," says Johannes Krause, Director of the Department of Archaeogenetics at the Max Planck Institute for Human History.
Read more at Science Daily
Social inequality already existed in southern Germany 4000 years ago, even within one household, a new study published in the journal Science finds. Archaeological and archaeogenetic analyses of Bronze Age cemeteries in the Lech Valley, near Augsburg, show that families of biologically related persons with higher status lived together with unrelated women who came from afar and also had a high status, according to their grave goods. In addition, a larger number of local but clearly less well-off individuals were found in the same cemeteries, which were small gravesites associated with single homesteads. The researchers conclude that social inequality was already part of households structures in that time and region. Whether the less well-off individuals were servants or slaves can only be speculated upon.
In Central Europe, the Bronze Age covers the period from 2200 to 800 BCE. At that time people acquired the ability to cast bronze. This knowledge led to an early globalization, since the raw materials had to be transported across Europe. In an earlier study, the current team had shown that, 4000 years ago, the majority of women in the Lech Valley came from abroad and may have played a decisive role in the transfer of knowledge. Supraregional networks were apparently fostered by marriages and institutionalized forms of mobility.
The current archaeological-scientific project was situated at the Heidelberg Academy of Sciences and led by Philipp Stockhammer from the Ludwig-Maximilians-Universitaet (LMU) in Munich together with Johannes Krause and Alissa Mittnik from the Max Planck Institute for the Science of Human History in Jena and the University of Tübingen. The researchers attempted to investigate the effects of this mobility and other concurrent changes. The excavations south of Augsburg, which took place at the sites of Bronze Age homestead farms and their associated graveyards, enabled archaeologists to zoom into the Bronze Age in unprecedented resolution in order to investigate how the transition from the Stone Age to the Bronze Age affected the households of that time. "Wealth was correlated with either biological kinship or foreign origin. The nuclear family passed on their property and status over generations. But at every farm we also found poorly equipped people of local origin," says Philipp Stockhammer, Professor of Prehistoric Archaeology at LMU Munich. This finding suggests a complex social structure of households, as is also known from Classical Greece and Rome. In Roman times, slaves were also part of the family unit, but had a different social status. However, these people in the Lech Valley lived over 1500 years earlier. "This shows how long the history of social inequality in family structures goes back in time," Stockhammer continues.
Stable social structures over 700 years
It was already known that the first larger hierarchical social structures evolved in the Bronze Age. The findings of the current study were surprising in that social differences existed within a single household and were maintained over generations.
Grave goods can reveal the social status of the deceased to archaeologists. In the Lech Valley, weapons and elaborate jewelry were only found in the graves of closely related family members and women who came into the family from long distances, up to several hundred kilometers away. Other unrelated individuals of local origin were found in the same cemeteries without such high-status grave goods.
This study also succeeded in reconstructing for the first time family trees from prehistoric cemeteries spanning four to five generations. Surprisingly, however, these only included the male lineages. The female descendants apparently left the farms where they reached adulthood. The mothers of the sons, on the other hand, were all women who had moved in from afar. "Archaeogenetics provides us with a completely new view of the past. Until recently, we would not have thought it possible to examine marriage rules, social structure and social inequality in prehistory," says Johannes Krause, Director of the Department of Archaeogenetics at the Max Planck Institute for Human History.
Read more at Science Daily
Rare sleep disorder common among veterans with PTSD
Military veterans with post-traumatic stress disorder or concussion suffer from a thrashing form of sleep behavior at a rate that is far higher than the general population, according to a new study by researchers at the VA Portland Health Care System and Oregon Health & Science University. The finding was published online this week in the journal SLEEP.
Researchers next want to probe whether the disorder, known as REM sleep behavior disorder, or RBD, might provide an early signal of the development of neurodegenerative conditions such as Parkinson's disease.
Normally during sleep that coincides with rapid eye movement, or REM sleep, muscles are effectively paralyzed. In cases of RBD, brain control of muscle paralysis is impaired, resulting in people acting out dreams during REM sleep, sometimes causing injuries to themselves or their partners. It is estimated to effect less than 1% of the general population.
That proportion rose to 9% of the 394 veterans in this study, and further swelled to 21% among those with PTSD.
"This is important because, in the general population, RBD has been linked to Parkinson's disease, and RBD often precedes classic symptoms of Parkinson's by years," said senior author Miranda Lim, M.D., Ph.D., a staff physician at the VA and assistant professor of neurology, medicine and behavioral neuroscience in the OHSU School of Medicine. "We don't know whether veterans who have PTSD and higher rates of RBD will go on to develop Parkinson's, but it is an important question we need to answer."
Researchers suspect chronic stress on the brain may play a role in causing the sleep disorder in veterans with PTSD, as many veterans have been exposed to concussion which potentially accelerates neurodegenerative processes.
Each study participant underwent an overnight sleep study at the VA Portland Health Care System between 2015 and 2017 to determine the presence of dream enactment during episodes of REM sleep. Muscle activity was monitored continuously during the 8 hours of the study in order to diagnose RBD. The study found that those with PTSD had over 2-fold increased odds of RBD compared to veterans without PTSD.
"RBD seems to be highly prevalent in veterans with a history of trauma," said lead author Jonathan Elliott, Ph.D., a research physiologist at the Portland VA and assistant professor of neurology in the OHSU School of Medicine.
Doctors involved in the study, including co-authors Kristianna Weymann, Ph.D., R.N., a clinical assistant professor in OHSU School of Nursing, and Dennis Pleshakov, a student at the OHSU School of Medicine, will continue to track research participants with RBD, looking for early signs of Parkinson's or other neurodegenerative conditions.
Although there are several therapies to ease some of the symptoms of Parkinson's, including tremor and fatigue, so far there has been no definitive therapy to prevent it.
Clinical trials for promising therapies are usually conducted well after patients have been diagnosed with Parkinson's, at a stage which may be too late to reverse the symptoms. Lim said that identifying patients with RBD presents an opportunity to identify people earlier in the disease course, and potentially provides a more viable window to test promising interventions.
Read more at Science Daily
Researchers next want to probe whether the disorder, known as REM sleep behavior disorder, or RBD, might provide an early signal of the development of neurodegenerative conditions such as Parkinson's disease.
Normally during sleep that coincides with rapid eye movement, or REM sleep, muscles are effectively paralyzed. In cases of RBD, brain control of muscle paralysis is impaired, resulting in people acting out dreams during REM sleep, sometimes causing injuries to themselves or their partners. It is estimated to effect less than 1% of the general population.
That proportion rose to 9% of the 394 veterans in this study, and further swelled to 21% among those with PTSD.
"This is important because, in the general population, RBD has been linked to Parkinson's disease, and RBD often precedes classic symptoms of Parkinson's by years," said senior author Miranda Lim, M.D., Ph.D., a staff physician at the VA and assistant professor of neurology, medicine and behavioral neuroscience in the OHSU School of Medicine. "We don't know whether veterans who have PTSD and higher rates of RBD will go on to develop Parkinson's, but it is an important question we need to answer."
Researchers suspect chronic stress on the brain may play a role in causing the sleep disorder in veterans with PTSD, as many veterans have been exposed to concussion which potentially accelerates neurodegenerative processes.
Each study participant underwent an overnight sleep study at the VA Portland Health Care System between 2015 and 2017 to determine the presence of dream enactment during episodes of REM sleep. Muscle activity was monitored continuously during the 8 hours of the study in order to diagnose RBD. The study found that those with PTSD had over 2-fold increased odds of RBD compared to veterans without PTSD.
"RBD seems to be highly prevalent in veterans with a history of trauma," said lead author Jonathan Elliott, Ph.D., a research physiologist at the Portland VA and assistant professor of neurology in the OHSU School of Medicine.
Doctors involved in the study, including co-authors Kristianna Weymann, Ph.D., R.N., a clinical assistant professor in OHSU School of Nursing, and Dennis Pleshakov, a student at the OHSU School of Medicine, will continue to track research participants with RBD, looking for early signs of Parkinson's or other neurodegenerative conditions.
Although there are several therapies to ease some of the symptoms of Parkinson's, including tremor and fatigue, so far there has been no definitive therapy to prevent it.
Clinical trials for promising therapies are usually conducted well after patients have been diagnosed with Parkinson's, at a stage which may be too late to reverse the symptoms. Lim said that identifying patients with RBD presents an opportunity to identify people earlier in the disease course, and potentially provides a more viable window to test promising interventions.
Read more at Science Daily
Oct 12, 2019
Black holes stunt growth of dwarf galaxies
Astronomers at the University of California, Riverside, have discovered that powerful winds driven by supermassive black holes in the centers of dwarf galaxies have a significant impact on the evolution of these galaxies by suppressing star formation.
Dwarf galaxies are small galaxies that contain between 100 million to a few billion stars. In contrast, the Milky Way has 200-400 billion stars. Dwarf galaxies are the most abundant galaxy type in the universe and often orbit larger galaxies.
The team of three astronomers was surprised by the strength of the detected winds.
"We expected we would need observations with much higher resolution and sensitivity, and we had planned on obtaining these as a follow-up to our initial observations," said Gabriela Canalizo, a professor of physics and astronomy at UC Riverside, who led the research team. "But we could see the signs strongly and clearly in the initial observations. The winds were stronger than we had anticipated."
Canalizo explained that astronomers have suspected for the past couple of decades that supermassive black holes at the centers of large galaxies can have a profound influence on the way large galaxies grow and age.
"Our findings now indicate that their effect can be just as dramatic, if not more dramatic, in dwarf galaxies in the universe," she said.
Study results appear in The Astrophysical Journal.
The researchers, who also include Laura V. Sales, an assistant professor of physics and astronomy; and Christina M. Manzano-King, a doctoral student in Canalizo's lab, used a portion of the data from the Sloan Digital Sky Survey, which maps more than 35% of the sky, to identify 50 dwarf galaxies, 29 of which showed signs of being associated with black holes in their centers. Six of these 29 galaxies showed evidence of winds -- specifically, high-velocity ionized gas outflows -- emanating from their active black holes.
"Using the Keck telescopes in Hawaii, we were able to not only detect, but also measure specific properties of these winds, such as their kinematics, distribution, and power source -- the first time this has been done," Canalizo said. "We found some evidence that these winds may be changing the rate at which the galaxies are able to form stars."
Manzano-King, the first author of the research paper, explained that many unanswered questions about galaxy evolution can be understood by studying dwarf galaxies.
"Larger galaxies often form when dwarf galaxies merge together," she said. "Dwarf galaxies are, therefore, useful in understanding how galaxies evolve. Dwarf galaxies are small because after they formed, they somehow avoided merging with other galaxies. Thus, they serve as fossils by revealing what the environment of the early universe was like. Dwarf galaxies are the smallest galaxies in which we are directly seeing winds -- gas flows up to 1,000 kilometers per second -- for the first time."
Manzano-King explained that as material falls into a black hole, it heats up due to friction and strong gravitational fields and releases radiative energy. This energy pushes ambient gas outward from the center of the galaxy into intergalactic space.
"What's interesting is that these winds are being pushed out by active black holes in the six dwarf galaxies rather than by stellar processes such as supernovae," she said. "Typically, winds driven by stellar processes are common in dwarf galaxies and constitute the dominant process for regulating the amount of gas available in dwarf galaxies for forming stars."
Astronomers suspect that when wind emanating from a black hole is pushed out, it compresses the gas ahead of the wind, which can increase star formation. But if all the wind gets expelled from the galaxy's center, gas becomes unavailable and star formation could decrease. The latter appears to be what is occurring in the six dwarf galaxies the researchers identified.
"In these six cases, the wind has a negative impact on star formation," Sales said. "Theoretical models for the formation and evolution of galaxies have not included the impact of black holes in dwarf galaxies. We are seeing evidence, however, of a suppression of star formation in these galaxies. Our findings show that galaxy formation models must include black holes as important, if not dominant, regulators of star formation in dwarf galaxies."
Next, the researchers plan to study the mass and momentum of gas outflows in dwarf galaxies.
"This would better inform theorists who rely on such data to build models," Manzano-King said. "These models, in turn, teach observational astronomers just how the winds affect dwarf galaxies. We also plan to do a systematic search in a larger sample of the Sloan Digital Sky Survey to identify dwarf galaxies with outflows originating in active black holes."
Read more at Science Daily
Dwarf galaxies are small galaxies that contain between 100 million to a few billion stars. In contrast, the Milky Way has 200-400 billion stars. Dwarf galaxies are the most abundant galaxy type in the universe and often orbit larger galaxies.
The team of three astronomers was surprised by the strength of the detected winds.
"We expected we would need observations with much higher resolution and sensitivity, and we had planned on obtaining these as a follow-up to our initial observations," said Gabriela Canalizo, a professor of physics and astronomy at UC Riverside, who led the research team. "But we could see the signs strongly and clearly in the initial observations. The winds were stronger than we had anticipated."
Canalizo explained that astronomers have suspected for the past couple of decades that supermassive black holes at the centers of large galaxies can have a profound influence on the way large galaxies grow and age.
"Our findings now indicate that their effect can be just as dramatic, if not more dramatic, in dwarf galaxies in the universe," she said.
Study results appear in The Astrophysical Journal.
The researchers, who also include Laura V. Sales, an assistant professor of physics and astronomy; and Christina M. Manzano-King, a doctoral student in Canalizo's lab, used a portion of the data from the Sloan Digital Sky Survey, which maps more than 35% of the sky, to identify 50 dwarf galaxies, 29 of which showed signs of being associated with black holes in their centers. Six of these 29 galaxies showed evidence of winds -- specifically, high-velocity ionized gas outflows -- emanating from their active black holes.
"Using the Keck telescopes in Hawaii, we were able to not only detect, but also measure specific properties of these winds, such as their kinematics, distribution, and power source -- the first time this has been done," Canalizo said. "We found some evidence that these winds may be changing the rate at which the galaxies are able to form stars."
Manzano-King, the first author of the research paper, explained that many unanswered questions about galaxy evolution can be understood by studying dwarf galaxies.
"Larger galaxies often form when dwarf galaxies merge together," she said. "Dwarf galaxies are, therefore, useful in understanding how galaxies evolve. Dwarf galaxies are small because after they formed, they somehow avoided merging with other galaxies. Thus, they serve as fossils by revealing what the environment of the early universe was like. Dwarf galaxies are the smallest galaxies in which we are directly seeing winds -- gas flows up to 1,000 kilometers per second -- for the first time."
Manzano-King explained that as material falls into a black hole, it heats up due to friction and strong gravitational fields and releases radiative energy. This energy pushes ambient gas outward from the center of the galaxy into intergalactic space.
"What's interesting is that these winds are being pushed out by active black holes in the six dwarf galaxies rather than by stellar processes such as supernovae," she said. "Typically, winds driven by stellar processes are common in dwarf galaxies and constitute the dominant process for regulating the amount of gas available in dwarf galaxies for forming stars."
Astronomers suspect that when wind emanating from a black hole is pushed out, it compresses the gas ahead of the wind, which can increase star formation. But if all the wind gets expelled from the galaxy's center, gas becomes unavailable and star formation could decrease. The latter appears to be what is occurring in the six dwarf galaxies the researchers identified.
"In these six cases, the wind has a negative impact on star formation," Sales said. "Theoretical models for the formation and evolution of galaxies have not included the impact of black holes in dwarf galaxies. We are seeing evidence, however, of a suppression of star formation in these galaxies. Our findings show that galaxy formation models must include black holes as important, if not dominant, regulators of star formation in dwarf galaxies."
Next, the researchers plan to study the mass and momentum of gas outflows in dwarf galaxies.
"This would better inform theorists who rely on such data to build models," Manzano-King said. "These models, in turn, teach observational astronomers just how the winds affect dwarf galaxies. We also plan to do a systematic search in a larger sample of the Sloan Digital Sky Survey to identify dwarf galaxies with outflows originating in active black holes."
Read more at Science Daily
Drug reverses signs of liver disease in people living with HIV
Researchers at the National Institutes of Health and their colleagues at Massachusetts General Hospital (MGH) in Boston report that the injectable hormone tesamorelin reduces liver fat and prevents liver fibrosis (scarring) in people living with HIV. The study was conducted by the National Institute of Allergy and Infectious Diseases (NIAID) and the National Cancer Institute, both parts of NIH. The findings were published online today in The Lancet HIV.
"Many people living with HIV have overcome significant obstacles to live longer, healthier lives, though many still experience liver disease," said NIAID Director Anthony S. Fauci, M.D. "It is encouraging that tesamorelin, a drug already approved to treat other complications of HIV, may be effective in addressing non-alcoholic fatty liver disease."
Non-alcoholic fatty liver disease, or NAFLD, frequently occurs alongside HIV, affecting as many as 25% of people living with HIV in the developed world. However, no effective treatments currently exist to treat the condition, which is a risk factor for progressive liver disease and liver cancer. Investigators led by Colleen M. Hadigan, M.D., senior research physician in NIAID's Laboratory of Immunoregulation, and Steven K. Grinspoon, M.D., Chief of the Metabolism Unit at MGH, tested whether tesamorelin could decrease liver fat in men and women living with both HIV and NAFLD. Among the participants enrolled, 43% had at least mild fibrosis, and 33% met the diagnostic criteria for a more severe subset of NAFLD called nonalcoholic steatohepatitis (NASH). Thirty-one participants were randomized to receive daily 2-mg injections of tesamorelin, and 30 were randomized to receive identical-looking injections containing a placebo. Researchers provided nutritional counseling to all participants, as well as training in self-administering the daily injections. Researchers then compared measures of liver health in both groups at baseline and 12 months.
After one year, participants receiving tesamorelin had better liver health than those receiving placebo, as defined by reduction in hepatic fat fraction (HFF) -- the ratio of fat to other tissue in the liver. The healthy range for HFF is less than 5%. Thirty-five percent of study participants receiving tesamorelin achieved a normal HFF, while only 4% of those on placebo reached that range with nutritional advice alone. Overall, tesamorelin was well-tolerated and reduced participants' HFF by an absolute difference of 4.1% (corresponding to a 37% relative reduction from the beginning of the study). While nine participants receiving placebo experienced onset or worsening of fibrosis, only two participants in the tesamorelin group experienced the same. Additionally, levels of several blood markers associated with inflammation and liver damage -- including the enzyme alanine aminotransferase (ALT) -- decreased more among those taking tesamorelin compared to those on a placebo, particularly among those with increased levels at the beginning of the study.
Given these positive results, investigators suggest expanding the indication for tesamorelin to include people living with HIV who have been diagnosed with NAFLD. They also recommend additional research to determine if tesamorelin could contribute to long-term protection against serious liver disease in people without HIV.
"Our hope is that this intervention may help people living with HIV, as well as benefit HIV-negative people with liver abnormalities," said Dr. Hadigan. "Further research may inform us of the potential long-term benefits of this approach and develop formulations that can benefit everyone with liver disease, regardless of HIV status."
Egrifta (tesamorelin) was approved in 2010 by the U.S. Food and Drug Administration to reduce excess abdominal fat in HIV patients with lipodystrophy -- a complication characterized by an abnormal distribution of body fat initially associated with older classes of HIV medications. The most commonly reported side effects in previous clinical trials evaluating Egrifta included joint pain (arthralgia), skin redness and rash at the injection site (erythema and pruritis), stomach pain, swelling, and muscle pain (myalgia). Worsening blood sugar control occurred more often in trial participants treated with Egrifta than with placebo.
"Because tesamorelin proved effective in treating abnormal fat build-up in the abdomens of people in the context of HIV and related medication use, we hypothesized that the drug might also reduce fat that accrues in the liver and causes damage in a similar population," said Dr. Grinspoon.
While liver disease is often associated with heavy alcohol use, NAFLD occurs when excess fat builds up in the liver without alcohol as a contributing factor. This condition may progress to liver damage, cirrhosis or cancer that could be life-threatening and necessitate liver transplantation.
Read more at Science Daily
"Many people living with HIV have overcome significant obstacles to live longer, healthier lives, though many still experience liver disease," said NIAID Director Anthony S. Fauci, M.D. "It is encouraging that tesamorelin, a drug already approved to treat other complications of HIV, may be effective in addressing non-alcoholic fatty liver disease."
Non-alcoholic fatty liver disease, or NAFLD, frequently occurs alongside HIV, affecting as many as 25% of people living with HIV in the developed world. However, no effective treatments currently exist to treat the condition, which is a risk factor for progressive liver disease and liver cancer. Investigators led by Colleen M. Hadigan, M.D., senior research physician in NIAID's Laboratory of Immunoregulation, and Steven K. Grinspoon, M.D., Chief of the Metabolism Unit at MGH, tested whether tesamorelin could decrease liver fat in men and women living with both HIV and NAFLD. Among the participants enrolled, 43% had at least mild fibrosis, and 33% met the diagnostic criteria for a more severe subset of NAFLD called nonalcoholic steatohepatitis (NASH). Thirty-one participants were randomized to receive daily 2-mg injections of tesamorelin, and 30 were randomized to receive identical-looking injections containing a placebo. Researchers provided nutritional counseling to all participants, as well as training in self-administering the daily injections. Researchers then compared measures of liver health in both groups at baseline and 12 months.
After one year, participants receiving tesamorelin had better liver health than those receiving placebo, as defined by reduction in hepatic fat fraction (HFF) -- the ratio of fat to other tissue in the liver. The healthy range for HFF is less than 5%. Thirty-five percent of study participants receiving tesamorelin achieved a normal HFF, while only 4% of those on placebo reached that range with nutritional advice alone. Overall, tesamorelin was well-tolerated and reduced participants' HFF by an absolute difference of 4.1% (corresponding to a 37% relative reduction from the beginning of the study). While nine participants receiving placebo experienced onset or worsening of fibrosis, only two participants in the tesamorelin group experienced the same. Additionally, levels of several blood markers associated with inflammation and liver damage -- including the enzyme alanine aminotransferase (ALT) -- decreased more among those taking tesamorelin compared to those on a placebo, particularly among those with increased levels at the beginning of the study.
Given these positive results, investigators suggest expanding the indication for tesamorelin to include people living with HIV who have been diagnosed with NAFLD. They also recommend additional research to determine if tesamorelin could contribute to long-term protection against serious liver disease in people without HIV.
"Our hope is that this intervention may help people living with HIV, as well as benefit HIV-negative people with liver abnormalities," said Dr. Hadigan. "Further research may inform us of the potential long-term benefits of this approach and develop formulations that can benefit everyone with liver disease, regardless of HIV status."
Egrifta (tesamorelin) was approved in 2010 by the U.S. Food and Drug Administration to reduce excess abdominal fat in HIV patients with lipodystrophy -- a complication characterized by an abnormal distribution of body fat initially associated with older classes of HIV medications. The most commonly reported side effects in previous clinical trials evaluating Egrifta included joint pain (arthralgia), skin redness and rash at the injection site (erythema and pruritis), stomach pain, swelling, and muscle pain (myalgia). Worsening blood sugar control occurred more often in trial participants treated with Egrifta than with placebo.
"Because tesamorelin proved effective in treating abnormal fat build-up in the abdomens of people in the context of HIV and related medication use, we hypothesized that the drug might also reduce fat that accrues in the liver and causes damage in a similar population," said Dr. Grinspoon.
While liver disease is often associated with heavy alcohol use, NAFLD occurs when excess fat builds up in the liver without alcohol as a contributing factor. This condition may progress to liver damage, cirrhosis or cancer that could be life-threatening and necessitate liver transplantation.
Read more at Science Daily
Oct 11, 2019
The Milky Way kidnapped several tiny galaxies from its neighbor
Just like the moon orbits the Earth, and the Earth orbits the sun, galaxies orbit each other according to the predictions of cosmology.
For example, more than 50 discovered satellite galaxies orbit our own galaxy, the Milky Way. The largest of these is the Large Magellanic Cloud, or LMC, a large dwarf galaxy that resembles a faint cloud in the Southern Hemisphere night sky.
A team of astronomers led by scientists at the University of California, Riverside, has discovered that several of the small -- or "dwarf" -- galaxies orbiting the Milky Way were likely stolen from the LMC, including several ultrafaint dwarfs, but also relatively bright and well-known satellite galaxies, such as Carina and Fornax.
The researchers made the discovery by using new data gathered by the Gaia space telescope on the motions of several nearby galaxies and contrasting this with state-of-the-art cosmological hydrodynamical simulations. The UC Riverside team used the positions in the sky and the predicted velocities of material, such as dark matter, accompanying the LMC, finding that at least four ultrafaint dwarfs and two classical dwarfs, Carina and Fornax, used to be satellites of the LMC. Through the ongoing merger process, however, the more massive Milky Way used its powerful gravitational field to tear apart the LMC and steal these satellites, the researchers report.
"These results are an important confirmation of our cosmological models, which predict that small dwarf galaxies in the universe should also be surrounded by a population of smaller fainter galaxy companions," said Laura Sales, an assistant professor of physics and astronomy, who led the research team. "This is the first time that we are able to map the hierarchy of structure formation to such faint and ultrafaint dwarfs."
The findings have important implications for the total mass of the LMC and also on the formation of the Milky Way.
"If so many dwarfs came along with the LMC only recently, that means the properties of the Milky Way satellite population just 1 billion years ago were radically different, impacting our understanding of how the faintest galaxies form and evolve," Sales said.
Study results appear in the November 2019 issue of the Monthly Notices of the Royal Astronomical Society.
Dwarf galaxies are small galaxies that contain anywhere from a few thousand to a few billion stars. The researchers used computer simulations from the Feedback In Realistic Environments project to show the LMC and galaxies similar to it host numerous tiny dwarf galaxies, many of which contain no stars at all -- only dark matter, a type of matter scientists think constitutes the bulk of the universe's mass.
"The high number of tiny dwarf galaxies seems to suggest the dark matter content of the LMC is quite large, meaning the Milky Way is undergoing the most massive merger in its history, with the LMC, its partner, bringing in as much as one third of the mass in the Milky Way's dark matter halo -- the halo of invisible material that surrounds our galaxy," said Ethan Jahn, the first author of the paper and a graduate student in Sales' research group.
Jahn explained that the number of tiny dwarf galaxies the LMC hosts may be higher than astronomers previously estimated, and that many of these tiny satellites have no stars.
"Small galaxies are hard to measure, and it's possible that some already-known ultrafaint dwarf galaxies are in fact associated with the LMC," he said. "It's also possible that we will discover new ultrafaints that are associated with the LMC."
Dwarf galaxies can either be satellites of larger galaxies, or they can be "isolated," existing on their own and independent of any larger object. The LMC used to be isolated, Jahn explained, but it was captured by the gravity of the Milky Way and is now its satellite.
"The LMC hosted at least seven satellite galaxies of its own, including the Small Magellanic Cloud in the Southern Sky, prior to them being captured by the Milky Way," he said.
Next, the team will study how the satellites of LMC-sized galaxies form their stars and how that relates to how much dark matter mass they have.
Read more at Science Daily
For example, more than 50 discovered satellite galaxies orbit our own galaxy, the Milky Way. The largest of these is the Large Magellanic Cloud, or LMC, a large dwarf galaxy that resembles a faint cloud in the Southern Hemisphere night sky.
A team of astronomers led by scientists at the University of California, Riverside, has discovered that several of the small -- or "dwarf" -- galaxies orbiting the Milky Way were likely stolen from the LMC, including several ultrafaint dwarfs, but also relatively bright and well-known satellite galaxies, such as Carina and Fornax.
The researchers made the discovery by using new data gathered by the Gaia space telescope on the motions of several nearby galaxies and contrasting this with state-of-the-art cosmological hydrodynamical simulations. The UC Riverside team used the positions in the sky and the predicted velocities of material, such as dark matter, accompanying the LMC, finding that at least four ultrafaint dwarfs and two classical dwarfs, Carina and Fornax, used to be satellites of the LMC. Through the ongoing merger process, however, the more massive Milky Way used its powerful gravitational field to tear apart the LMC and steal these satellites, the researchers report.
"These results are an important confirmation of our cosmological models, which predict that small dwarf galaxies in the universe should also be surrounded by a population of smaller fainter galaxy companions," said Laura Sales, an assistant professor of physics and astronomy, who led the research team. "This is the first time that we are able to map the hierarchy of structure formation to such faint and ultrafaint dwarfs."
The findings have important implications for the total mass of the LMC and also on the formation of the Milky Way.
"If so many dwarfs came along with the LMC only recently, that means the properties of the Milky Way satellite population just 1 billion years ago were radically different, impacting our understanding of how the faintest galaxies form and evolve," Sales said.
Study results appear in the November 2019 issue of the Monthly Notices of the Royal Astronomical Society.
Dwarf galaxies are small galaxies that contain anywhere from a few thousand to a few billion stars. The researchers used computer simulations from the Feedback In Realistic Environments project to show the LMC and galaxies similar to it host numerous tiny dwarf galaxies, many of which contain no stars at all -- only dark matter, a type of matter scientists think constitutes the bulk of the universe's mass.
"The high number of tiny dwarf galaxies seems to suggest the dark matter content of the LMC is quite large, meaning the Milky Way is undergoing the most massive merger in its history, with the LMC, its partner, bringing in as much as one third of the mass in the Milky Way's dark matter halo -- the halo of invisible material that surrounds our galaxy," said Ethan Jahn, the first author of the paper and a graduate student in Sales' research group.
Jahn explained that the number of tiny dwarf galaxies the LMC hosts may be higher than astronomers previously estimated, and that many of these tiny satellites have no stars.
"Small galaxies are hard to measure, and it's possible that some already-known ultrafaint dwarf galaxies are in fact associated with the LMC," he said. "It's also possible that we will discover new ultrafaints that are associated with the LMC."
Dwarf galaxies can either be satellites of larger galaxies, or they can be "isolated," existing on their own and independent of any larger object. The LMC used to be isolated, Jahn explained, but it was captured by the gravity of the Milky Way and is now its satellite.
"The LMC hosted at least seven satellite galaxies of its own, including the Small Magellanic Cloud in the Southern Sky, prior to them being captured by the Milky Way," he said.
Next, the team will study how the satellites of LMC-sized galaxies form their stars and how that relates to how much dark matter mass they have.
Read more at Science Daily
Sharing data for improved forest protection and monitoring
Although the mapping of aboveground biomass is now possible with satellite remote sensing, these maps still have to be calibrated and validated using on-site data gathered by researchers across the world. IIASA contributed to the establishment of a new global database to support Earth Observation and encourage investment in relevant field-based measurements and research.
Forest biomass is an essential indicator for monitoring the Earth's ecosystems and climate. It also provides critical input to greenhouse gas accounting, estimation of carbon losses and forest degradation, assessment of renewable energy potential, and for developing climate change mitigation policies. Although satellite remote sensing technology now allows researchers to produce extensive maps of aboveground biomass, these maps still require reliable, up-to-date, on-site data for calibration and validation. Collecting data in the field by measuring trees and documenting species is, however, a very labor intensive, expensive, and time-consuming exercise and it would therefore make sense to bring together the many extant data sets to provide real added value for a number of applications. In terms of policy applications, doing so can also lead to improved biomass products and better monitoring of forest resources, which could in turn lead to more effective forest protection measures.
In a new paper published in the journal Scientific Data, 143 researchers involved in this type of data collection in the field, explored whether it was possible to build a network that openly shares their data on biomass for the benefit of different communities. They particularly wanted to see if they could bring together as much on-site data on biomass as possible to prepare for new satellite missions, such as the European Space Agency's BIOMASS mission, with a view to improving the accuracy of current remote sensing based products, and developing new synergies between remote sensing and ground-based ecosystem research communities. Their efforts have resulted in the establishment of the Forest Observation System (FOS) -- an international, collaborative initiative that aims to establish a global on-site forest aboveground biomass database to support Earth Observation and to encourage investment in relevant field-based measurements and research.
"Keeping in mind that this paper is a data descriptor and not a conventional paper with hypotheses, the whole idea behind this study is a new open database on biomass data. This is important for the following reasons: First, it represents a way to link the ecological/forestry and remote sensing communities. It also overcomes existing data sharing barriers, while promoting data sharing beyond small, siloed communities. Lastly, it provides recognition to the people working in the field, including those who collect the data, which is why there are 143 coauthors on this paper, as they are all contributors to the database," explains study lead author Dmitry Shchepashchenko, a researcher in the IIASA Ecosystems Services and Management Program.
The researchers collected data from 1,645 permanent forest sample plots from 274 locations distributed around the globe. This data has now been made available for download via the FOS website. The initiative represents the first attempt at bringing this type of data together from different networks in a single location. The researchers point out that their work in this regard is ongoing and there are plans to continue adding more data sets and networks to the FOS. In addition to promoting data sharing, the system also promotes a new leading network on biomass data (through the FOS), which IIASA is leading and will continue to grow into the future.
Apart from the obvious benefits that data sharing hold for the scientific community, the data are also essential for training various models at IIASA such as the BioGeoChemistry Management Model (BGC-MAN) and the Global Forest Model (G4M). Several on-going IIASA projects, as well as other ecological-, biophysical-, and economic models and projects outside of IIASA will also benefit, which means that providing access to the data can improve models and understanding of biomass more generally.
Read more at Science Daily
Forest biomass is an essential indicator for monitoring the Earth's ecosystems and climate. It also provides critical input to greenhouse gas accounting, estimation of carbon losses and forest degradation, assessment of renewable energy potential, and for developing climate change mitigation policies. Although satellite remote sensing technology now allows researchers to produce extensive maps of aboveground biomass, these maps still require reliable, up-to-date, on-site data for calibration and validation. Collecting data in the field by measuring trees and documenting species is, however, a very labor intensive, expensive, and time-consuming exercise and it would therefore make sense to bring together the many extant data sets to provide real added value for a number of applications. In terms of policy applications, doing so can also lead to improved biomass products and better monitoring of forest resources, which could in turn lead to more effective forest protection measures.
In a new paper published in the journal Scientific Data, 143 researchers involved in this type of data collection in the field, explored whether it was possible to build a network that openly shares their data on biomass for the benefit of different communities. They particularly wanted to see if they could bring together as much on-site data on biomass as possible to prepare for new satellite missions, such as the European Space Agency's BIOMASS mission, with a view to improving the accuracy of current remote sensing based products, and developing new synergies between remote sensing and ground-based ecosystem research communities. Their efforts have resulted in the establishment of the Forest Observation System (FOS) -- an international, collaborative initiative that aims to establish a global on-site forest aboveground biomass database to support Earth Observation and to encourage investment in relevant field-based measurements and research.
"Keeping in mind that this paper is a data descriptor and not a conventional paper with hypotheses, the whole idea behind this study is a new open database on biomass data. This is important for the following reasons: First, it represents a way to link the ecological/forestry and remote sensing communities. It also overcomes existing data sharing barriers, while promoting data sharing beyond small, siloed communities. Lastly, it provides recognition to the people working in the field, including those who collect the data, which is why there are 143 coauthors on this paper, as they are all contributors to the database," explains study lead author Dmitry Shchepashchenko, a researcher in the IIASA Ecosystems Services and Management Program.
The researchers collected data from 1,645 permanent forest sample plots from 274 locations distributed around the globe. This data has now been made available for download via the FOS website. The initiative represents the first attempt at bringing this type of data together from different networks in a single location. The researchers point out that their work in this regard is ongoing and there are plans to continue adding more data sets and networks to the FOS. In addition to promoting data sharing, the system also promotes a new leading network on biomass data (through the FOS), which IIASA is leading and will continue to grow into the future.
Apart from the obvious benefits that data sharing hold for the scientific community, the data are also essential for training various models at IIASA such as the BioGeoChemistry Management Model (BGC-MAN) and the Global Forest Model (G4M). Several on-going IIASA projects, as well as other ecological-, biophysical-, and economic models and projects outside of IIASA will also benefit, which means that providing access to the data can improve models and understanding of biomass more generally.
Read more at Science Daily
Habitual tea drinking modulates brain efficiency: Evidence from brain connectivity evaluation
The researchers recruited healthy older participants to two groups according to their history of tea drinking frequency and investigated both functional and structural networks to reveal the role of tea drinking on brain organization.
The suppression of hemispheric asymmetry in the structural connectivity network was observed as a result of tea drinking.
The authors did not observe any significant effects of tea drinking on the hemispheric asymmetry of the functional connectivity network.
Dr. Junhua Li and Dr. Lei Feng said, "Tea has been a popular beverage since antiquity, with records referring to consumption dating back to the dynasty of Shen Nong (approximately 2700 BC) in China."
Tea is consumed in diverse ways, with brewed tea and products with a tea ingredient extremely prevalent in Asia, especially in China and Japan.
Although individual constituents of tea have been related to the roles of maintaining cognitive abilities and preventing cognitive decline, a study with behavioural and neurophysiological measures showed that there was a degraded effect or no effect when a constituent was administered alone and a significant effect was observed only when constituents were combined.
The superior effect of the constituent combination was also demonstrated in a comparative experiment that suggested that tea itself should be administered instead of tea extracts; a review of tea effects on the prevention of Alzheimers disease, found that the neuroprotective role of herbal tea was apparent in eight out of nine studies.
It is worth noting that the majority of studies thus far have evaluated tea effects from the perspective of neurocognitive and neuropsychological measures, with direct measurement of brain structure or function less-well represented in the extant literature.
These studies focusing on brain regional alterations did not ascertain tea effects on interregional interactions at the level of the entire brain.
The Li/Feng Research team concluded, "In summary, our study comprehensively investigated the effects of tea drinking on brain connectivity at both global and regional scales using multi-modal imaging data and provided the first compelling evidence that tea drinking positively contributes to brain structure making network organization more efficient."
From Science Daily
The suppression of hemispheric asymmetry in the structural connectivity network was observed as a result of tea drinking.
The authors did not observe any significant effects of tea drinking on the hemispheric asymmetry of the functional connectivity network.
Dr. Junhua Li and Dr. Lei Feng said, "Tea has been a popular beverage since antiquity, with records referring to consumption dating back to the dynasty of Shen Nong (approximately 2700 BC) in China."
Tea is consumed in diverse ways, with brewed tea and products with a tea ingredient extremely prevalent in Asia, especially in China and Japan.
Although individual constituents of tea have been related to the roles of maintaining cognitive abilities and preventing cognitive decline, a study with behavioural and neurophysiological measures showed that there was a degraded effect or no effect when a constituent was administered alone and a significant effect was observed only when constituents were combined.
The superior effect of the constituent combination was also demonstrated in a comparative experiment that suggested that tea itself should be administered instead of tea extracts; a review of tea effects on the prevention of Alzheimers disease, found that the neuroprotective role of herbal tea was apparent in eight out of nine studies.
It is worth noting that the majority of studies thus far have evaluated tea effects from the perspective of neurocognitive and neuropsychological measures, with direct measurement of brain structure or function less-well represented in the extant literature.
These studies focusing on brain regional alterations did not ascertain tea effects on interregional interactions at the level of the entire brain.
The Li/Feng Research team concluded, "In summary, our study comprehensively investigated the effects of tea drinking on brain connectivity at both global and regional scales using multi-modal imaging data and provided the first compelling evidence that tea drinking positively contributes to brain structure making network organization more efficient."
From Science Daily
Slower walkers have older brains and bodies at 45
The walking speed of 45-year-olds, particularly their fastest walking speed without running, can be used as a marker of their aging brains and bodies.
Slower walkers were shown to have "accelerated aging" on a 19-measure scale devised by researchers, and their lungs, teeth and immune systems tended to be in worse shape than the people who walked faster.
"The thing that's really striking is that this is in 45-year-old people, not the geriatric patients who are usually assessed with such measures," said lead researcher Line J.H. Rasmussen, a post-doctoral researcher in the Duke University department of psychology & neuroscience.
Equally striking, neurocognitive testing that these individuals took as children could predict who would become the slower walkers. At age 3, their scores on IQ, understanding language, frustration tolerance, motor skills and emotional control predicted their walking speed at age 45.
"Doctors know that slow walkers in their seventies and eighties tend to die sooner than fast walkers their same age," said senior author Terrie E. Moffitt, the Nannerl O. Keohane University Professor of Psychology at Duke University, and Professor of Social Development at King's College London. "But this study covered the period from the preschool years to midlife, and found that a slow walk is a problem sign decades before old age."
The data come from a long-term study of nearly 1,000 people who were born during a single year in Dunedin, New Zealand. The 904 research participants in the current study have been tested, quizzed and measured their entire lives, mostly recently from April 2017 to April 2019 at age 45.
The study appears Oct. 11 in JAMA Network Open.
MRI exams during their last assessment showed the slower walkers tended to have lower total brain volume, lower mean cortical thickness, less brain surface area and higher incidence of white matter "hyperintensities," small lesions associated with small vessel disease of the brain. In short, their brains appeared somewhat older.
Adding insult to injury perhaps, the slower walkers also looked older to a panel of eight screeners who assessed each participant's 'facial age' from a photograph.
Gait speed has long been used as a measure of health and aging in geriatric patients, but what's new in this study is the relative youth of these study subjects and the ability to see how walking speed matches up with health measures the study has collected during their lives.
"It's a shame we don't have gait speed and brain imaging for them as children," Rasmussen said. (The MRI was invented when they were five, but was not given to children for many years after.)
Read more at Science Daily
Slower walkers were shown to have "accelerated aging" on a 19-measure scale devised by researchers, and their lungs, teeth and immune systems tended to be in worse shape than the people who walked faster.
"The thing that's really striking is that this is in 45-year-old people, not the geriatric patients who are usually assessed with such measures," said lead researcher Line J.H. Rasmussen, a post-doctoral researcher in the Duke University department of psychology & neuroscience.
Equally striking, neurocognitive testing that these individuals took as children could predict who would become the slower walkers. At age 3, their scores on IQ, understanding language, frustration tolerance, motor skills and emotional control predicted their walking speed at age 45.
"Doctors know that slow walkers in their seventies and eighties tend to die sooner than fast walkers their same age," said senior author Terrie E. Moffitt, the Nannerl O. Keohane University Professor of Psychology at Duke University, and Professor of Social Development at King's College London. "But this study covered the period from the preschool years to midlife, and found that a slow walk is a problem sign decades before old age."
The data come from a long-term study of nearly 1,000 people who were born during a single year in Dunedin, New Zealand. The 904 research participants in the current study have been tested, quizzed and measured their entire lives, mostly recently from April 2017 to April 2019 at age 45.
The study appears Oct. 11 in JAMA Network Open.
MRI exams during their last assessment showed the slower walkers tended to have lower total brain volume, lower mean cortical thickness, less brain surface area and higher incidence of white matter "hyperintensities," small lesions associated with small vessel disease of the brain. In short, their brains appeared somewhat older.
Adding insult to injury perhaps, the slower walkers also looked older to a panel of eight screeners who assessed each participant's 'facial age' from a photograph.
Gait speed has long been used as a measure of health and aging in geriatric patients, but what's new in this study is the relative youth of these study subjects and the ability to see how walking speed matches up with health measures the study has collected during their lives.
"It's a shame we don't have gait speed and brain imaging for them as children," Rasmussen said. (The MRI was invented when they were five, but was not given to children for many years after.)
Read more at Science Daily
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