Scientists were wrong for decades about DNA knots

Scientists at the University of Cambridge, working with international collaborators, have identified a crucial process that shapes how DNA behaves as it moves through nanoscale pores. This process is fundamental to many biological activities and to fast-growing DNA sensing technologies. The research highlights a long-overlooked DNA structure called plectonemes, a finding that could influence future advances in genomics and biosensing.

Nanopores are extremely small openings that allow single strands of DNA to pass through while producing electrical signals. These signals help researchers analyze genetic material in detail. Until now, important features of those signals had been misunderstood.

Why Scientists Thought DNA Was Forming Knots

For many years, researchers believed that complex electrical patterns seen during nanopore experiments were caused by DNA forming knots. The idea was easy to picture. Pulling a shoelace through a narrow hole becomes uneven if the lace tangles, and scientists assumed DNA behaved in the same way. Any irregular signal was thought to mean the strand had knotted as it moved through the pore.

That explanation shaped how nanopore data was interpreted for decades.

Twists, Not Knots, Explain the Signals

The new study, published in Physical Review X, shows that this long-standing assumption was often wrong. Instead of forming true knots, DNA frequently twists around itself during nanopore translocation. These twisted structures, known as plectonemes, resemble a coiled phone cord rather than a tied knot.

This distinction matters because twists and knots affect electrical signals in very different ways.

“Our experiments showed that as DNA is pulled through the nanopore, the ionic flow inside twists the strand, accumulating torque and winding it into plectonemes, not just knots. This ‘hidden’ twisting structure has a distinctive, long-lasting fingerprint in the electrical signal, unlike the more transient signature of knots,” explained lead author Dr Fei Zheng from the Cavendish Laboratory.

Experiments Point to a Missing Mechanism

To reach this conclusion, the researchers tested DNA using both glass and silicon nitride nanopores across a wide range of voltages and conditions. They noticed that so-called “tangled” events, when more than one section of DNA occupied the pore at the same time, occurred far more often than knot theory could explain.

These events became even more frequent as voltage increased and as DNA strands grew longer. This pattern suggested that another force was at work.

How Flowing Water Twists DNA

The team found that the twisting comes from electroosmotic flow, the movement of water driven by electric fields inside the nanopore. As water flows past the DNA, it applies a spinning force to the helical molecule. This torque travels along the strand, causing sections outside the pore to coil into plectonemes.

Unlike knots, which tighten under pulling forces and typically disappear quickly, plectonemes can grow larger and remain present throughout the entire translocation process. Computer simulations that applied realistic forces and torques confirmed this behavior and showed that plectoneme formation depends on DNA’s ability to transmit twist along its length.

Blocking Twists Confirms the Discovery

To test the idea further, the researchers created “nicked” DNA, strands that were interrupted at specific points. These interruptions prevented twist from spreading along the molecule and sharply reduced the formation of plectonemes during experiments.

This result confirmed that twist propagation is essential to the process. It also hints at new ways nanopores could be used to detect DNA damage, since breaks in the strand interfere with twisting behavior.

Reading DNA Signals With New Precision

“What’s really powerful here is that we can now tell apart knots and plectonemes in the nanopore signal based on how long they last,” says Prof Ulrich F. Keyser, also from the Cavendish Laboratory and a co-author of the study.

“Knots pass through quickly, just like a quick bump, whereas plectonemes linger and create extended signals. This offers a path to richer, more nuanced readouts of DNA organization, genomic integrity, and possibly damage.”

Broader Implications for Biology and Technology

The findings extend beyond nanopore sensing. In living cells, DNA regularly twists and tangles as enzymes act on it, and both knots and plectonemes play important roles in genome organization and stability. Understanding how these structures form could improve models of cellular DNA behavior.

For diagnostics and biosensing, the ability to detect or control DNA twisting could lead to more sensitive tools capable of identifying subtle genetic changes and early signs of DNA damage linked to disease.

“From the perspective of nanotechnology, the research highlights the power of nanopores, not only as sophisticated sensors but also as tools for manipulating biopolymers in novel ways,” concluded Keyser.

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This popular diet was linked to a much lower stroke risk

Women who follow a Mediterranean-style eating pattern may face a lower risk of stroke, according to research published on February 4, 2026, in Neurology Open Access, a journal of the American Academy of Neurology. The study found a strong relationship between this diet and reduced stroke risk, though it does not show that the diet directly prevents strokes. Instead, it identifies an association between dietary habits and long-term health outcomes.

Researchers observed lower rates of stroke overall among women who most closely followed the Mediterranean diet. This included both ischemic strokes and hemorrhagic strokes. Ischemic strokes occur when blood flow to part of the brain is blocked and are the most common form of stroke. Hemorrhagic strokes happen when a blood vessel ruptures and causes bleeding in the brain.

What Defines the Mediterranean Diet

The Mediterranean diet centers on eating plenty of vegetables, fruits, legumes, and fish, along with healthy fats such as olive oil. It limits foods like dairy products, meat, and items high in saturated fatty acids.

“Our findings support the mounting evidence that a healthy diet is critical to stroke prevention,” said study author Sophia S. Wang, PhD, of City of Hope Comprehensive Cancer Center in Duarte, California. “We were especially interested to see that this finding applies to hemorrhagic stroke, as few large studies have looked at this type of stroke.”

How the Study Followed More Than 100,000 Women

The study included 105,614 women who had no history of stroke at the beginning of the research and an average age of 53. Each participant completed a detailed diet questionnaire at the start of the study. Researchers then assigned a score ranging from zero to nine based on how closely each person’s diet matched Mediterranean diet guidelines.

Participants earned one point for consuming more than the population average of whole grain cereals, fruits, vegetables, legumes, olive oil, and fish, as well as for drinking a moderate amount of alcohol. They also earned a point for eating less red meat and dairy than average. About 30% of participants scored between six and nine — the highest group. Another 13% scored between zero and two, placing them in the lowest group.

Stroke Outcomes Over 21 Years

Participants were monitored for an average of 21 years. During that period, researchers recorded 4,083 strokes, including 3,358 ischemic strokes and 725 hemorrhagic strokes. Among women in the highest diet score group, 1,058 ischemic strokes occurred, compared with 395 cases in the lowest group. For hemorrhagic stroke, 211 cases were reported in the highest group and 91 in the lowest group.

After accounting for other stroke risk factors such as smoking, physical activity, and high blood pressure, the differences remained significant. Women with the highest Mediterranean diet scores were 18% less likely to experience any stroke than those with the lowest scores. Their risk of ischemic stroke was 16% lower, and their risk of hemorrhagic stroke was 25% lower.

Why the Findings Matter and Study Limitations

“Stroke is a leading cause of death and disability, so it’s exciting to think that improving our diets could lessen our risk for this devastating disease,” said Wang. “Further studies are needed to confirm these findings and to help us understand the mechanisms behind them so we could identify new ways to prevent stroke.”

One limitation of the study is that dietary information was self reported, which means some participants may not have recalled their eating habits accurately.

The research was funded by the National Institute of Neurological Diseases and Stroke.

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A secret cell alliance may explain why ovarian cancer is so deadly

Ovarian cancer is the deadliest gynecological cancer, largely because it is usually discovered too late. In most cases, doctors diagnose the disease only after it has already spread widely throughout the abdomen. Although researchers have long known that ovarian cancer progresses rapidly, the biological reason behind this speed has remained unclear.

A new study led by Nagoya University now sheds light on this long-standing mystery. The research, published in Science Advances, shows that ovarian cancer cells do not act alone. Instead, they enlist help from mesothelial cells, which normally serve as a protective lining inside the abdominal cavity. These mesothelial cells move ahead of the cancer cells, creating pathways that cancer cells then follow. Together, they form hybrid cell clusters that are more resistant to chemotherapy than cancer cells by themselves.

Cancer Cells Form Hybrid Clusters in Abdominal Fluid

To understand how this happens, researchers analyzed abdominal fluid from patients with ovarian cancer. What they found challenged previous assumptions. Cancer cells were rarely drifting freely on their own. Instead, they frequently attached themselves to mesothelial cells, forming compact, mixed cell spheres.

The researchers estimated that roughly 60% of these cancer spheres included recruited mesothelial cells. The cancer cells release a signaling molecule known as TGF-β1, which alters the mesothelial cells. In response, the mesothelial cells develop sharp, spike-like protrusions capable of cutting through surrounding tissue.

How Ovarian Cancer Moves Through the Abdomen

As ovarian cancer grows, some cells detach from the main tumor and enter the fluid-filled space within the abdomen. This fluid is constantly in motion due to normal breathing and body movement. As a result, cancer cells are carried to many different areas of the abdominal cavity.

This method of spread differs sharply from that of many other cancers. In diseases such as breast or lung cancer, tumor cells enter blood vessels and travel through the bloodstream to distant organs. Because blood flows through defined pathways, doctors can sometimes monitor these cancers using blood tests.

Ovarian cancer cells largely bypass blood vessels. Instead, they drift through abdominal fluid that lacks a predictable route. This floating phase occurs before the cells attach to new organs. Until now, scientists did not fully understand what occurred during this stage or how cancer cells coordinated their spread so efficiently.

Invadopodia Drive Tissue Invasion

The research team found that during this floating stage, ovarian cancer cells actively recruit mesothelial cells that have naturally shed from the abdominal lining. Once joined together, the two cell types form hybrid spheres. The mesothelial cells then produce invadopodia, which are spike-like structures that drill into nearby tissue.

These hybrid spheres pose a particular threat. When they reach an organ, they invade tissue more rapidly and withstand chemotherapy drugs more effectively than cancer cells alone.

Watching Cancer Spread in Real Time

Using advanced microscopy, the scientists were able to observe this process directly in abdominal fluid samples from patients. They validated their observations with experiments in mouse models and by analyzing gene activity at the single-cell level.

Lead author Dr. Kaname Uno, a former PhD student and current Visiting Researcher at Nagoya University’s Graduate School of Medicine, explained that the cancer cells themselves remain relatively unchanged. “They manipulate mesothelial cells to do the tissue invasion work. They undergo minimal genetic and molecular changes and just migrate through the openings that mesothelial cells create.”

Before entering research, Dr. Uno spent eight years working as a gynecologist. One patient profoundly shaped his decision to pursue this line of study. She had received normal screening results just three months before doctors diagnosed her with advanced ovarian cancer. Existing diagnostic tools failed to detect the disease early enough to save her life. That experience motivated Dr. Uno to investigate why ovarian cancer spreads so quickly and escapes early detection.

New Opportunities for Treatment and Monitoring

The findings point to potential new approaches for treating ovarian cancer. Current chemotherapy drugs focus on destroying cancer cells but do not target the mesothelial cells that assist in invasion. Future therapies could aim to block the TGF-β1 signal or prevent the formation of these harmful cell partnerships.

The study also suggests a possible new way to track the disease. Monitoring these hybrid cell clusters in abdominal fluid could help doctors better predict how ovarian cancer will progress and how patients respond to treatment.

Ovarian cancer kills more women than any other gynecological cancer. Most patients receive their diagnosis only after the disease spreads throughout the abdomen. Until now, scientists have never fully understood why this cancer advances so fast.

A new study led by Nagoya University explains why. Published in Science Advances, the study shows that cancer cells recruit help from protective mesothelial cells that normally line the abdominal cavity. Mesothelial cells lead the invasion and cancer cells follow the pathways they create. These hybrid cell clusters resist chemotherapy better than cancer alone.

Researchers examined abdominal fluid from ovarian cancer patients and found something unexpected. Cancer cells do not float alone in the abdominal cavity. Instead, they often grab onto mesothelial cells and form hybrid spheres. About 60% of all cancer spheres contain these recruited mesothelial cells. The cancer cells release a protein called TGF-β1 that transforms the mesothelial cells and causes them to develop spike-like structures that cut through tissue.

Invadopodia, spike structures that do the digging for cancer

When ovarian cancer develops, cancer cells break off from the tumor. These cells enter the abdominal fluid and float freely. The fluid moves around as you breathe and move your body. This movement carries the cancer cells to different spots in the abdomen.

Most other cancers spread differently. Breast cancer or lung cancer cells enter blood vessels. They travel through the bloodstream to reach distant organs. Doctors can sometimes track these cancers through blood tests because blood moves in predictable paths through vessels.

Ovarian cancer cells avoid blood vessels entirely. They float in fluid that has no fixed path. This floating stage happens before the cancer cells attach to new organs. Scientists did not fully understand what happened during the floating period or how cells worked together to spread cancer so quickly.

The research team discovered that cancer cells recruit protective mesothelial cells that have shed from the abdominal cavity lining during this floating stage. The two cell types stick together and form hybrid spheres. The mesothelial cells then grow invadopodia, spike-like structures that drill into surrounding tissue. The hybrid spheres resist chemotherapy drugs more effectively and invade tissues faster when they land on organs.

Outsourcing the hard work of cell invasion

The researchers examined abdominal fluid from ovarian cancer patients using advanced microscopy to watch this process in real time. They confirmed their findings with mouse models and single-cell genetic analysis.

Lead author Dr. Kaname Uno, a former PhD student and current Visiting Researcher at Nagoya University’s Graduate School of Medicine, explained that the cancer cells do not need to become more invasive themselves. “They manipulate mesothelial cells to do the tissue invasion work. They undergo minimal genetic and molecular changes and just migrate through the openings that mesothelial cells create.”

Dr. Uno worked as a gynecologist for eight years before he pursued research. One of his patients changed his career path. She had clear screening results just three months before doctors found advanced ovarian cancer. Current medical tools failed to detect the cancer early enough to save her life. This motivated Dr. Uno to investigate why ovarian cancer spreads so rapidly.

This discovery opens new treatment possibilities. Current chemotherapy targets cancer cells but ignores the mesothelial accomplices. Future drugs could block the TGF-β1 signal or prevent the formation of these dangerous partnerships. The research also suggests that doctors could monitor these cell clusters in abdominal fluid to predict disease progression and treatment response.

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Why are fewer people donating their organs?

The number waiting for an organ is at a record high as loved ones increasingly block donations.

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‘Weight-loss jab helped me find my cancer’

Rebecca Combellack says she found out she had breast cancer after losing weight and finding a lump.

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New drug resets the body clock and cuts jet lag recovery nearly in half

A research team led by scientists from several Japanese institutions has identified a compound called Mic-628 that directly influences the body’s internal timing system. The group included Emeritus Professor Tei H. (Kanazawa University), Associate Professor Takahata Y. (Osaka University), Professor Numano R. (Toyohashi University of Technology), and Associate Professor Uriu K. (Institute of Science Tokyo). Their experiments showed that Mic-628 specifically activates Per1, a core gene that helps regulate daily biological rhythms in mammals.

The researchers found that Mic-628 works by attaching to CRY1, a protein that normally suppresses clock gene activity. This interaction encourages the formation of a larger molecular complex known as CLOCK-BMAL1-CRY1-Mic-628. Once formed, this complex switches on Per1 by acting at a specific DNA site called a “dual E-box.” Through this mechanism, Mic-628 shifts the timing of both the brain’s master clock located in the suprachiasmatic nucleus (SCN) and clocks in other organs, including the lungs. Notably, these clock shifts occurred together and did not depend on when the compound was given.

Faster Recovery From Jet Lag in Animal Tests

To test real-world relevance, the team used a mouse model designed to mimic jet lag by advancing the light-dark cycle by six hours (6-hour light-dark phase advance). Mice that received a single oral dose of Mic-628 adjusted to the new schedule much faster, taking four days instead of seven. Further mathematical analysis showed that this steady, one-direction shift forward is driven by a built-in feedback loop involving the PER1 protein, which helps stabilize the clock change.

Why Advancing the Clock Is So Difficult

Adjusting to earlier schedules, such as traveling east across time zones or working night shifts, requires the body clock to move forward. This type of adjustment is typically slower and more stressful for the body than delaying the clock. Common approaches like light exposure or melatonin depend heavily on precise timing and often produce uneven results. Because Mic-628 consistently advances the clock regardless of dosing time, it offers a fundamentally different drug-based approach to circadian reset.

What Comes Next for Mic-628

The researchers plan to continue studying Mic-628 to better understand its safety and effectiveness in additional animal studies and in humans. Since the compound reliably moves the body clock forward through a clearly defined biological pathway, it could become a model “smart drug” for addressing jet lag, sleep problems linked to shift work, and other disorders caused by circadian misalignment.

The findings were published in the Proceedings of the National Academy of Sciences of the United States of America (PNAS).

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Scientists found a gut compound that helps protect the liver

Children whose mothers eat a diet high in fat and sugar during pregnancy and breastfeeding face a greater chance of developing fatty liver disease later in life. New findings from the University of Oklahoma suggest that this risk may be lowered. In the study, pregnant and nursing mice given a naturally occurring compound made by healthy gut bacteria had offspring with much lower rates of fatty liver disease as they grew older.

The compound studied is called indole. It is produced by beneficial gut bacteria when they break down tryptophan, an amino acid found in foods like turkey and nuts. The results add to growing research focused on preventing metabolic dysfunction-associated steatotic liver disease (MASLD). This form of fatty liver disease affects both adults and children, but it often advances more quickly in children and is closely linked to diabetes.

“The prevalence of MASLD in children is about 30% in those with obesity and about 10% in children without obesity,” said Jed Friedman, Ph.D., director of the OU Health Harold Hamm Diabetes Center and professor of biochemistry and physiology in the OU College of Medicine. “Unfortunately, the risk is higher if a mother is obese or consumes a poor diet. The disease in children is silent and typically isn’t discovered until a parent seeks help for their child for liver-related symptoms.”

Testing the Role of the Microbiome

Friedman led the study alongside Karen Jonscher, Ph.D., associate professor of biochemistry and physiology in the OU College of Medicine. Their work was published in the journal eBioMedicine. The team set out to explore whether gut bacteria, known together as the microbiome, influence how fatty liver disease develops.

To investigate this, female mice were fed a high-fat, high-sugar (Western-style) diet throughout pregnancy and lactation. Some of the mice also received indole. After they were weaned, the offspring were placed on a standard diet and later switched to a Western-style diet to encourage the development of fatty liver disease.

“Because offspring inherit their microbiome from their mother, a poor maternal diet can shape the infant’s microbiome in harmful ways,” Friedman said.

Healthier Livers and Lasting Benefits

Offspring born to mothers that received indole showed multiple health advantages. They had healthier livers, gained less weight, maintained lower blood sugar levels, and developed smaller fat cells, even after being exposed to an unhealthy diet later in life. The researchers also observed activation of a protective gut pathway involving the acyl hydrocarbon receptor (AHR).

The study found no increase in harmful liver fats known as long-chain ceramides, while levels of beneficial very long-chain ceramides rose. In a key experiment, gut bacteria from the protected offspring were transferred to other mice that had not received indole. Those mice also experienced less liver damage, reinforcing the idea that the microbiome itself plays a central protective role.

Implications for Preventing Childhood MASLD

Although the research was conducted in animals and cannot yet be applied directly to humans, the findings point to new strategies for reducing the growing impact of MASLD through early prevention.

At present, weight loss is the only effective treatment option for pediatric MASLD once the disease is established, and there are no approved medications. “Anything we can do to improve the mother’s microbiome may help prevent the development of MASLD in the offspring,” Jonscher said. “That would be far better than trying to reverse the disease once it has already progressed.”

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Scientists warn climate models are missing a key ocean player

Some of the most important players in Earth’s climate system are nearly invisible. Calcifying plankton, microscopic organisms that form hard shells, help regulate the planet’s temperature by capturing carbon and moving it through the ocean. A new review published in Science finds that these organisms are not fully represented in the climate models used to predict Earth’s future. The research was led by an international team from the Institute of Environmental Science and Technology at the Universitat Autònoma de Barcelona (ICTA-UAB) (Spain).

The study focuses on three major groups of calcifying plankton: coccolithophores, foraminifers, and pteropods. According to the authors, climate models often simplify or exclude these organisms, which can lead to an incomplete picture of how the ocean responds to climate change.

How Calcifying Plankton Shape the Carbon Cycle

When climate models leave out calcifying plankton, they may miss key steps in the global carbon cycle. These organisms build tiny shells made of calcium carbonate (CaCO3), a substance that plays a central role in ocean chemistry. As plankton grow and die, they help move carbon from the atmosphere into deeper layers of the ocean.

This process, known as the ocean carbon pump, helps stabilize Earth’s climate over long periods of time. It also affects seawater chemistry and contributes to the formation of sediments that scientists use to study past climates.

“Plankton shells are tiny, but together they shape the chemistry of our oceans and the climate of our planet,” said Patrizia Ziveri, ICREA research professor at ICTA-UAB and lead author of the study. “By leaving them out of climate models, we risk overlooking fundamental processes that determine how the Earth system responds to climate change.”

The Missing Process of Shallow Dissolution

The researchers point out that much of the calcium carbonate produced by plankton does not sink all the way to the ocean floor. Instead, a significant portion dissolves in the upper ocean, a process known as “shallow dissolution.” This breakdown is driven by biological activity, including predation, clumping of particles, and microbial respiration.

Shallow dissolution changes ocean chemistry in important ways, yet it is largely missing from major Earth System Models (e.g. CMIP6) used in global climate assessments. Without accounting for this process, models may misjudge how carbon moves through the ocean and how the system responds to environmental stress.

Different Plankton Face Different Climate Threats

The study also emphasizes that not all calcifying plankton behave the same way. Each group has unique characteristics that influence where it lives, how it functions in marine ecosystems, and how vulnerable it is to climate change.

Coccolithophores are the largest producers of CaCO3, but they are especially sensitive to ocean acidification because they lack specialized mechanisms to remove excess acidity from their cells. Foraminifers and pteropods do have such mechanisms, but they face other risks, including declining oxygen levels and rising ocean temperatures. Together, these organisms determine how carbon is stored and recycled in the ocean, and treating them as a single group can oversimplify the ocean’s response to climate pressures.

Improving Climate Models With Better Ocean Biology

The authors call for urgent efforts to measure how much calcium carbonate each plankton group produces, dissolves, and exports to deeper waters. They argue that incorporating these details into climate models would improve predictions of ocean and atmosphere interactions, long-term carbon storage, and the interpretation of sediment records used to reconstruct Earth’s climate history.

“If we ignore the ocean’s smallest organisms, we might miss important climate dynamics,” says Dr. Ziveri. “Integrating calcifying plankton into climate models could offer sharper predictions and deeper insights into how ecosystems and societies may be affected.”

The researchers conclude that closing these knowledge gaps is essential for building the next generation of climate models, ones that more accurately reflect the biological complexity of the oceans.

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How COVID and H1N1 swept through U.S. cities in just weeks

Public health scientists at the Columbia University Mailman School of Public Health used advanced computer simulations to trace how the 2009 H1N1 flu pandemic and the 2020 COVID-19 pandemic spread across the United States. Their results show how quickly respiratory pandemics can expand and why stopping them early is so challenging. Published in the journal Proceedings of the National Academy of Sciences, the research is the first to directly compare how these two pandemics moved through U.S. metropolitan areas.

Both outbreaks had major consequences in the United States. The 2009 H1N1 flu pandemic led to 274,304 hospitalizations and 12,469 deaths. The COVID-19 pandemic has been even more devastating, with 1.2 million confirmed deaths reported so far.

Modeling the Spread Across Cities

The researchers aimed to understand how these pandemics traveled geographically in order to improve planning for future outbreaks. To do this, they combined detailed information about how each virus spreads with computer models that accounted for air travel, everyday commuting, and the possibility of superspreading events. Their analysis focused on more than three hundred metropolitan areas across the U.S.

Rapid Expansion Before Early Warnings

The simulations revealed that both pandemics were already circulating widely in most metro areas within just a few weeks. This widespread transmission often occurred before early case detection or government response measures were in place. Although H1N1 and COVID-19 followed different routes between locations, both relied on shared transmission hubs, including major metro areas such as New York and Atlanta. Air travel played a much larger role than commuting in driving this rapid spread. At the same time, unpredictable transmission patterns added significant uncertainty, making it difficult to anticipate where outbreaks would emerge in real time.

“The rapid and uncertain spread of the 2009 H1N1 flu and 2020 COVID-19 pandemics underscores the challenges for timely detection and control. Expanding wastewater surveillance coverage coupled with effective infection control could potentially slow the initial spread of future pandemics,” says the study’s senior author, Sen Pei, PhD, assistant professor of environmental health sciences at Columbia Mailman School.

Wastewater Surveillance and Pandemic Preparedness

Previous research has highlighted the value of wastewater surveillance as an early warning tool. This new study adds further support, showing that expanding wastewater monitoring could play an important role in improving pandemic preparedness and slowing early transmission.

Lessons Beyond H1N1 and COVID-19

In addition to reconstructing the spread of the last two pandemics, the researchers developed a flexible framework that can be used to study the early stages of other outbreaks. While human movement, especially air travel, is a major driver of pandemic spread, the team notes that other factors also influence how outbreaks unfold. These include population demographics, school calendars, winter holidays, and weather patterns.

The study’s first author is Renquan Zhang, Dalian University of Technology, Dalian, China. Additional authors include Rui Deng and Sitong Liu from Dalian University of Technology; Qing Yao and Jeffrey Shaman from Columbia University; Bryan T. Grenfell from Princeton; and Cécile Viboud from the National Institutes of Health.

For more than ten years, Jeffrey Shaman and colleagues, including Sen Pei, have worked to improve methods for tracking and simulating the spread of infectious diseases such as influenza and COVID-19. Their real-time forecasting tools estimate how quickly outbreaks grow, where they are likely to spread, and when they may peak, helping guide public health decision-making.

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Menopause linked to grey matter loss in key brain regions

New findings from the University of Cambridge suggest that menopause is associated with changes in brain structure, along with higher levels of anxiety, depression, and sleep difficulties. Researchers found reduced grey matter volume in several important brain regions among women who had gone through menopause.

The study, published in Psychological Medicine, also examined the effects of hormone replacement therapy (HRT). While HRT did not appear to prevent these brain or mental health changes, it was associated with a slower decline in reaction speed.

Understanding Menopause and Its Symptoms

Menopause marks the stage of life when a woman’s menstrual periods permanently stop due to declining hormone levels. It most commonly occurs between ages 45 and 55 and is often accompanied by symptoms such as hot flushes, low mood, and disrupted sleep. Previous research has also linked menopause to changes in cognitive abilities, including memory, attention, and language.

To help manage menopause related symptoms, particularly depression and sleep problems, many women are prescribed HRT. In England, 15% of women were prescribed HRT in 2023. Despite its widespread use, scientists still have limited insight into how menopause and HRT affect the brain, thinking skills, and mental health.

A Large Study Using UK Biobank Data

To better understand these effects, researchers analyzed data from the UK Biobank involving nearly 125,000 women. Participants were divided into three groups: women who had not yet reached menopause, women who were post-menopause and had never used HRT, and women who were post-menopause and had used HRT.

Participants completed questionnaires about menopause symptoms, mental health, sleep patterns, and overall health. Some also completed cognitive tests measuring memory and reaction time. In addition, around 11,000 women underwent magnetic resonance imaging (MRI) scans, which allowed researchers to examine differences in brain structure.

The average age at menopause among participants was about 49.5 years. Women who were prescribed HRT typically began treatment at around age 49.

Anxiety Depression and Sleep After Menopause

Women who had gone through menopause were more likely than those who had not to seek help from a GP or psychiatrist for anxiety, nervousness, or depression. They also scored higher on depression questionnaires and were more likely to have been prescribed antidepressant medications.

Women in the HRT group showed higher levels of anxiety and depression compared with women who did not use HRT. However, further analysis revealed that these differences were already present before menopause began. According to the researchers, this suggests that some GPs may have prescribed HRT in anticipation that menopause could worsen existing symptoms.

Sleep problems were also more common after menopause. Post-menopausal women were more likely to report insomnia, reduced sleep, and ongoing tiredness. Women using HRT reported feeling the most fatigued of all three groups, even though their total sleep duration did not differ from post-menopausal women who were not taking HRT.

The Importance of Lifestyle and Mental Health Support

Dr. Christelle Langley from the Department of Psychiatry said: “Most women will go through menopause, and it can be a life-changing event, whether they take HRT or not. A healthy lifestyle — exercising, keeping active and eating a healthy diet, for example — is particularly important during this period to help mitigate some of its effects.

“We all need to be more sensitive to not only the physical, but also the mental health of women during menopause, however, and recognize when they are struggling. There should be no embarrassment in letting others know what you’re going through and asking for help.”

Reaction Time Slows While Memory Remains Stable

Menopause was also linked to changes in cognitive performance. Women who were post-menopause and not using HRT showed slower reaction times compared with women who had not yet reached menopause and those who were using HRT. Memory performance did not differ significantly among the three groups.

Dr. Katharina Zühlsdorff from the Department of Psychology at the University of Cambridge, said: “As we age, our reaction times tend to get slower — it’s just a part of the natural ageing process and it happens to both women and men. You can imagine being asked a question at a quiz — while you might still arrive at the correct answer as your younger self, younger people would no doubt get there much faster. Menopause seems to accelerate this process, but HRT appears to put the brakes on, slowing the ageing process slightly.”

Grey Matter Loss in Brain Regions Linked to Memory and Emotion

Brain imaging revealed that women who were post-menopause showed significant reductions in grey matter volume, regardless of whether they had used HRT. Grey matter contains nerve cell bodies and plays a key role in processing information, controlling movement, and supporting memory and emotional regulation.

The most affected areas included the hippocampus (responsible for forming and storing memories), the entorhinal cortex (the ‘gateway’ for passing information between the hippocampus and the rest of the brain), and the anterior cingulate cortex (part of the brain that helps you manage emotions, make decisions, and focus your attention).

Possible Clues to Dementia Risk in Women

Professor Barbara Sahakian, the study’s senior author from the Department of Psychiatry, added: “The brain regions where we saw these differences are ones that tend to be affected by Alzheimer’s disease. Menopause could make these women vulnerable further down the line. While not the whole story, it may help explain why we see almost twice as many cases of dementia in women than in men.”

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