Publisher Health

From changes in daylight across seasons to the artificial lighting choices in workplaces, it’s clear that the quantity and quality of light that a person encounters can significantly impact mood.
Now, scientists at Brown University think they know why.
In a new study published in the Proceedings of the National Academy of Science, the research team used functional MRI to reveal how light-intensity signals reach the brain, and how brain structures involved in mood process those signals. The study demonstrated that some regions of the cerebral cortex involved in cognitive processing and mood show sensitivity for light intensity.
The discovery has implications for understanding mood problems like seasonal affective disorder and major depressive disorders, as well as how to treat them, said lead study author Jerome Sanes, a Brown professor of neuroscience affiliated with the University’s Carney Institute for Brain Science.
“Identifying this pathway and understanding its function might directly promote development of approaches to treat depression, either by pharmacological manipulations or non-invasive brain stimulation in selected nodes of the pathway or with targeted bright-light therapy,” Sanes said.
The findings build on previous research by study co-author David Berson, a Brown professor of neuroscience, who in 2002 discovered special light-sensing cells in the eye. Unlike rods and cones, these “intrinsically photosensitive retinal ganglion cells” are not involved in what’s known as “object vision” or “form vision,” Sanes said, but mainly function to sense light intensity.

Increases in three climate factors — temperature, rainfall, and ocean warming — predicted mosquito population growth in Sri Lanka for the next one to six months, according to a new study by an international team of researchers. The findings, published in The Lancet Planetary Health, can inform the design and timing of programs to limit the spread of mosquito-borne diseases like dengue.
Nearly half of the world’s population lives in areas at risk for dengue, which has become a major public health problem in Sri Lanka. Because developing a safe and effective vaccine against dengue has proven to be difficult, controlling mosquito populations is considered to be the most effective strategy to prevent the virus’s spread.
Dengue transmission patterns in Sri Lanka closely follow the country’s monsoonal rainfalls, with peak transmission in July following the southwest monsoon, followed by a smaller peak in December to January after the northeast monsoon. Research shows a relationship between some climate variables and the quantity, feeding patterns, and lifespan of Aedes mosquitoes, which transmit dengue, but the relationship between Aedes mosquito activity and climate is still not well understood.
“Dengue transmission is expected to intensify due to climate change. If we can use climate and weather data to predict seasonal patterns of mosquitos, this timely information would allow public health authorities to proactively manage mosquito control operations,” said study author Yesim Tozan, assistant professor of global health at NYU School of Global Public Health.
The researchers aimed to quantify the effect of climate on Aedes mosquitoes in Kalutara, a district in southwestern Sri Lanka with a persistent, high presence of dengue. They measured three monthly weather variables — rainfall, temperature, and Oceanic Niño Index — from 2010 to 2018. The Oceanic Niño Index measures whether waters in the tropical Pacific Ocean are warmer or cooler than average, with El Niño and La Niña phases triggering changes in weather. Three El Niño events, or unusually warm ocean temperatures, occurred from 2010 to 2018.
The researchers then compared the climate variables with systematically collected surveillance data of mosquitoes in Kalutara, including measurements of Aedes mosquitoes and larvae found in homes and outdoor water containers.
All three climate variables predicted mosquito activity, but with different time lags. More rainfall — which often led to outdoor containers filling with water, creating mosquito breeding sites — predicted a greater prevalence of mosquitoes within the same month. Hotter temperatures were associated with increases in mosquitoes one to two months later. The warmer ocean temperatures of El Niño events predicted increases in mosquitoes with a five to six months delay.
“These climate factors have the potential to serve as predictors of mosquito activity at different times and may enable us to quantify the risk and implement effective mosquito control interventions before a dengue epidemic emerges,” said the study’s lead author Prasad Liyanage of the Sri Lanka Ministry of Health and Umeå University in Sweden, who will join NYU School of Global Public Health this fall as a postdoctoral associate.
“Tracking El Niño events has the added advantage of predicting the seasonal prevalence of Aedes mosquitoes with a lead time of six months, which could provide opportunities to issue early warnings on mosquito prevalence for the entire dengue season,” added Tozan.
Additional study authors include Hans Overgaard of the Norwegian University of Life Sciences and Khon Kaen University in Thailand, Hasitha Aravinda Tissera of the Sri Lanka Ministry of Health, and Joacim Rocklöv of Umeå University and Heidelberg University in Germany.
Story Source:
Materials provided by New York University. Note: Content may be edited for style and length.

A research team lead by scientists from the Max Planck Institute for Biology, Tübingen, has now made substantial progress in understanding how gut bacteria succeed in their human hosts on a molecular level. They investigated how bacteria produce inositol lipids, substances vital for many cellular processes in humans and other eukaryotes but hitherto rarely observed in bacteria. The results, now published in the journal Nature Microbiology, indicate that inositol lipids have implications for the symbiosis between the bacteria and their hosts.
Microorganisms like bacteria and fungi populate the human gut and contribute to many biological functions such as metabolism or immunity. In order to understand the influence of the microbiome on humans, researchers have been trying to not only identify which microorganisms are present in the human gut, but also shed light on the molecular mechanisms of the interactions between the microbiome and its human host. A research team lead by scientists from the Max Planck Institute for Biology in Tübingen has now improved our understanding of these processes by investigating how gut bacteria produce a certain family of chemical compounds known as inositol lipids.
Inositol lipids: modulators of inflammation and cell signaling
Inositol lipids play important roles for many cellular processes in humans and most other non-bacterial life forms: they regulate how cells send signals throughout the body, modulate inflammation, and help ensure that proteins end up in to the correct part of a larger cell. Imbalances in inositol levels are linked to diseases like polycystic ovary syndrome, the most common hormone disorder in women of reproductive age. In contrast to humans and other eukaryotes for whom inositol lipids are essential, bacteria produce them relatively rarely. The research team led by Ruth Ley, scientific director of the Department of Microbiome Science at the MPI for Biology, was now able to describe inositol lipid synthesis in Bacteroides thetaiotaomicron, a common bacterium in the large intestine and a popular model organism in microbiome science. By developing a previously undescribed strain of Bacteroides thetaiotaomicron for which they could control whether inositol lipids were produced, the researchers discovered that these substances change the bacteria’s physiology. “Although we don’t fully understand the precise role of inositol lipids for bacterial fitness yet, we have seen that they are necessary for a bacterium to succeed in the gut of their host,” says Stacey Heaver, lead author of the publication. The researchers found inositol in the capsule of the bacteria, an outer layer which protects them against being engulfed by immune cells of the host. Moreover, inositol lipids change the resistance of Bacteroides thetaiotaomicron to antimicrobial peptides, substances used by the host to fight off pathogens.
Possible cross-talk between bacterial and host lipids
The researchers also described the metabolic pathways for inositol lipid synthesis in Bacteroides thetaiotaomicron, that is, the chain of chemical reactions leading to the production of inositol lipids. They additionally identified a second putative pathway for bacterial synthesis of these lipids. “Figuring out the pathways is interesting because it enables us predict which other microbes might be able to make inositol lipids the same way our model organism does,” explains Heaver. “With this knowledge, we might even be able to engineer or manipulate inositol lipid production.” Heaver looks forward to future research about if and how bacterial inositol lipids might benefit the host organism: “It is possible that there is a cross-talk between the bacterial lipids and the inositol lipids produced by the mammalian host,” she says. “We’ve just come a big step closer to understanding the scale of such interactions.”
Story Source:
Materials provided by Max-Planck-Gesellschaft. Note: Content may be edited for style and length.

Intermittent fasting has previously shown to have a host of health benefits, including lowering the risk of diabetes and heart disease. Now, researchers from Intermountain Healthcare have found that people who regularly fast are less like to experience severe complications from COVID-19.
In a new study published this week in BMJ Nutrition, Prevention & Health, Intermountain researchers found that COVID-19 patients who practiced regular water-only intermittent fasting had lower risk of hospitalization or dying due to the virus than patients who did not.
“Intermittent fasting has already shown to lower inflammation and improve cardiovascular health. In this study, we’re finding additional benefits when it comes to battling an infection of COVID-19 in patients who have been fasting for decades,” said Benjamin Horne, PhD, director of cardiovascular and genetic epidemiology at Intermountain Healthcare.
In the Intermountain study, researchers identified patients enrolled in the INSPIRE registry, a voluntary health registry at Intermountain Healthcare, who had also tested positive for SARS-CoV-2 between March 2020 and February 2021 — before vaccines were widely available.
They identified 205 patients who had tested positive for the virus. Of those, 73 said they regularly fasted at least once a month. Researchers found that those who practiced regular fasting had a lower rate of hospitalization or death due to coronavirus.
“Intermittent fasting was not associated with whether or not someone tested positive COVID-19, but it was associated with lower severity once patients had tested positive for it,” Dr. Horne said.

Konstantinos Kanatsaropoulos from Caister, Norfolk, spent two months in a coma after getting Covid. He was discharged from hospital in January and said he had suffered organ failures and a stroke – and was now “fighting every day” for his life.An intensive care doctor who looked him has called for better support for people with long-term effects.Find BBC News: East of England on Facebook, Instagram and Twitter. If you have a story suggestion email eastofenglandnews@bbc.co.uk

Older people with hypothyroidism, also called underactive thyroid, may be at increased risk of developing dementia, according to a study published in the July 6, 2022, online issue of Neurology®, the medical journal of the American Academy of Neurology. The risk of developing dementia was even higher for people whose thyroid condition required thyroid hormone replacement medication.
Hypothyroidism occurs when the thyroid gland doesn’t make enough thyroid hormones. This can slow metabolism. Symptoms include feeling tired, weight gain and sensitivity to cold.
“In some cases, thyroid disorders have been associated with dementia symptoms that can be reversible with treatment,” said study author Chien-Hsiang Weng, MD, MPH, of Brown University in Providence, Rhode Island. “While more studies are needed to confirm these findings, people should be aware of thyroid problems as a possible risk factor for dementia and therapies that could prevent or slow irreversible cognitive decline.”
For the study, researchers looked at the health records of 7,843 people newly diagnosed with dementia in Taiwan and compared them to the same number of people who did not have dementia. Their average age was 75. Researchers looked to see who had a history of either hypothyroidism or hyperthyroidism. Hyperthyroidism, which is also called overactive thyroid, is when the thyroid produces too much hormone. This can increase metabolism. Symptoms include unintended weight loss, rapid or irregular heartbeat and nervousness or anxiety.
A total of 102 people had hypothyroidism and 133 had hyperthyroidism.
The researchers found no link between hyperthyroidism and dementia.
Of the people with dementia, 68 people, or 0.9%, had hypothyroidism, compared to 34 of the people without dementia, or 0.4%. When researchers adjusted for other factors that could affect the risk of dementia, such as sex, age, high blood pressure and diabetes, they found that people over age 65 with hypothyroidism were 80% more likely to develop dementia than people the same age who did not have thyroid problems. For people younger than 65, having a history of hypothyroidism was not associated with an increased risk of dementia.
When researchers looked only at people who took medication for hypothyroidism, they found they were three times more likely to develop dementia than those who did not take medication. “One explanation for this could be that these people are more likely to experience greater symptoms from hypothyroidism where treatment was needed,” Weng said.
Weng noted that the observational study does not prove that hypothyroidism is a cause of dementia; it only shows an association.
A limitation of the study was that researchers were not able to include information about how severe the hypothyroidism was for participants.
Story Source:
Materials provided by American Academy of Neurology. Note: Content may be edited for style and length.

The eye’s light-sensing retina taps different circuits depending on whether it is generating image-forming vision or carrying out a non-vision function such as regulating pupil size or sleep/wake cycles, according to a new mouse study from the National Eye Institute (NEI) and the National Institute of Mental Health (NIMH). The findings could have implications for understanding how our eyes help regulate mood, digestion, sleep, and metabolism. NEI and NIMH are part of the National Institutes of Health.
“We know a lot about pathways involved in image-forming vision, but until now it remained unknown if and how non-image-forming visual behaviors rely on these same pathways in the eye,” said Johan Pahlberg, Ph.D., head of the Photoreceptor Physiology Group at NEI and a senior author of the study.
Vision begins when light travels into the eye and hits the retina’s light-sensing photoreceptors. The photoreceptors transfer signals through several layers of retinal neuron before those signals are sent to the brain. Light also triggers certain non-vision functions, such as controlling how much light enters the eye through the pupil (pupillary light reflex) and regulating the wake/sleep cycle (circadian rhythm). Circadian rhythm disruption has been linked to sleep problems, obesity, and other health issues.
To investigate pathways used by image-forming versus non-image-forming functions in the retina, Pahlberg and colleagues studied groups of mice that had been genetically modified to turn off one or more pathway links, or synapses, between photoreceptors and their next downstream neuronal neighbors, called bipolar cells. The group investigated the roles of rod photoreceptors, which are sensitive to low light levels; cone photoreceptors, which see color; as well as three types of bipolar cells: rod bipolar cells, “on” cone bipolar cells, and “off” cone bipolar cells.
“On” cone bipolar cells react to increases in light, and “off” cone bipolar cells react to decreases in light. Cone photoreceptors can only communicate with cone bipolar cells, while rod photoreceptors have pathways to communicate with each of the bipolar cell types, depending on the level of light. Bipolar cells then communicate with other neurons in the retina, passing information to the optic nerve and on to the brain. Some mice in the study had no functional connections between rods and “on” bipolar cells, for example, or connections between cones and any bipolar cells, or lacked connections between rod and cone photoreceptors.
The researchers compared the mice’s responses to visual stimuli while assessing pupillary light responses and monitoring their nocturnal wake/sleep cycle. They determined that while image-forming vision can use rod and cone photoreceptors, as well as all the types of bipolar cells, the same was not true for non-image forming functions. The pupil response relies exclusively on rod photoreceptors, while cones are unable to control this behavior. Meanwhile, both circadian rhythm regulation and the pupil reflex only use “on” bipolar cells pathways, relying on rod bipolar cells and “on” cone bipolar cells, but not “off” cone bipolar cells.
“We were really surprised to find that animals with only ‘off’ bipolar cells can’t adjust to changes in the day/night cycle, but can still see and respond to visual events, meaning they have functional image-forming vision. It was really interesting to us that the non-imaging forming functions completely ignore information from the ‘off’ pathway,” said Pahlberg. “We were equally surprised that rod photoreceptors, which are optimized for low light conditions, were still being used for the pupillary response even when light levels were high. We really thought the rods would be maxed out at that point.”
Pahlberg expects many of these findings in mice will hold true for humans, since the retinal circuitry is similar across mammals. Moving forward, he intends to explore other non-image-forming functions of the retina, like mood regulation, and see how else these different retinal circuits are being used.
The research was funded by the intramural programs of NEI, NIMH, the National Institute of Dental and Craniofacial Research, and the National Institute of Neurological Diseases and Stroke.
Story Source:
Materials provided by NIH/National Eye Institute. Note: Content may be edited for style and length.

COVID-19 vaccine acceptance increased 3.7% between 2020 and 2021, according to a new study from researchers at the CUNY Graduate School of Public Health and Health Policy (CUNY SPH), the Barcelona Institute for Global Health (ISGlobal), the Dalhousie University and the University of Calgary.
In a June 2021 survey of over 23,000 individuals across 23 countries, the researchers found that more than three-quarters (75.2%) of respondents reported vaccine acceptance, up from 71.5% one year earlier.
The study, which was published Monday in Nature Communications, was carried out within the context of a year of substantial but very unequal global COVID-19 vaccine availability and acceptance, which necessitated new assessments of the drivers of vaccine hesitancy and the characteristics of people not vaccinated.
Concerns about vaccine safety and efficacy and mistrust in the science behind vaccine development were the most consistent correlates of hesitancy. Other factors associated with vaccine hesitancy varied by country and included personal experience with COVID-19 (e.g., sickness or loss of a family member) and demographic characteristics (e.g., gender, education, and income).
The authors found that vaccine hesitancy did not significantly correlate with a country’s current COVID-19 case burden and mortality. In June 2021, vaccine hesitancy was reported most frequently in Russia (48.4%), Nigeria (43%), and Poland (40.7%), and least often in China (2.4%), the United Kingdom (UK) (18.8%), and Canada (20.8%).
“In order to improve global vaccination rates, some countries may at present require people to present proof of vaccination to attend work, school, or indoor activities and events,” says CUNY SPH Senior Scholar Jeffrey Lazarus. “Our results found strong support among participants for requirements targeting international travellers, while support was weakest among participants for requirements for schoolchildren.”
Support for vaccine mandates was substantially lower among those who were hesitant to get vaccinated themselves. “Importantly, however, recommendations by a doctor, or to a lesser extent by an employer, might have an impact on a respondent’s views on vaccination in some countries,” said CUNY SPH Dean Ayman El-Mohandes.
Although some countries are currently disengaging from evidence-based COVID-19 control measures, the disease has by no means been controlled or ended as a public health threat. The authors note that for ongoing COVID-19 vaccination campaigns to succeed in improving coverage going forward, substantial challenges remain. These include targeting those reporting lower vaccine confidence with evidence-based information campaigns and greatly expanding vaccine access in low- and middle-income countries.
The Role of Social Networks
ISGlobal and the Institute #SaludsinBulos, together with the Severo Ochoa Foundation and representatives of Spanish scientific and professional societies and patient associations, held a meeting on 20 June 2022 to advance the development of a consensus on addressing vaccine hesitancy. According to data presented from a European survey carried out by the Vaccine Confidence Project, the population group most exposed to social networks — young people under 24 years of age, with secondary or university studies and living in urban areas — are the most reluctant to be vaccinated. Additionally, messages that call for vaccination as a “moral obligation” are strongly rejected compared to those that call for “protection,” which are more commonly well received.
As reflected in similar studies, one of the most popular ways of conveying anti-vaccine messages has been humor. Therefore, participants in the meeting agreed on the need to disseminate the benefits of vaccines using this same tool, but without making fun of those who have mistaken beliefs about vaccines. In the face of misinformation, it is important to improve information on vaccination using simple language and channels that reach the population, such as social networks, the participants concluded.

A UCLA study offers the first evidence that transgender patients who receive gender-affirming facial feminization surgery reported better mental health after their procedures.
The study was published in the journal Annals of Surgery.
According to Dr. Justine Lee, UCLA’s Bernard G. Sarnat Professor of Craniofacial Biology, gender-affirming facial surgery is frequently classified by insurers as a cosmetic procedure, in part because of a lack of evidence that the procedure improves patients’ quality of life.
“Access to facial gender-affirming surgeries under health insurance coverage in the U.S. is more limited than gender-affirming surgeries of other anatomic regions due to a lack of data on mental health quality-of-life outcomes,” said Lee, who was the study’s lead author and is an associate professor of surgery at the David Geffen School of Medicine at UCLA. “Our findings have the potential to change health insurance policies for the better for transgender patients.”
Researchers compared mental health assessments for 107 patients who were awaiting surgery with those of 62 people who had already completed it, an average of a little more than 6 1/2 months after their procedures.
They found that people who had received the surgery reported higher scores in seven of 11 measures of psychosocial health — anxiety, anger, depression, global mental health, positive affect, social isolation, and meaning and purpose — than those who had not yet had the surgery.

Opioids are the gold standard for treatment of chronic and acute pain; however, their use may result in significant gastrointestinal side effects, including nausea, vomiting, and constipation. The reasons behind these side effects are not well understood. A new study in The American Journal of Pathology, published by Elsevier, is the first report of how opioids like morphine cause gastric inflammation and how this condition can be reversed through treatment with proton pump inhibitor drugs like omeprazole, an over-the-counter medication commonly used to reduce stomach acid.
“Because of a lack of better alternatives, morphine is still considered one of the best pain management drugs despite its association with significant comorbidities,” explained lead investigator Sabita Roy, PhD, Department of Surgery, Miller School of Medicine, University of Miami; and Sylvester Comprehensive Cancer Centre, Miami, FL, USA. “Several groups of researchers, including our own, have been working for a considerable time on understanding the phenomenon and deciphering the mechanism underlying the gastrointestinal adverse effects of morphine.”
Opioid users, compared with non-users, have a higher incidence of gastric dysfunction, greater levels of gastric retention, worse quality of life, increased hospitalizations, and increased use of antinausea and pain medications.
To investigate the effect of morphine on gastric inflammation, the researchers treated mice with morphine or a placebo. They found that morphine-mediated gastric damage is a consequence of the accumulation of acid in the stomach due to increased gastric acid secretion and delayed gastric emptying, thereby increasing the retention time of acid in the stomach. In vivo imaging confirmed that the morphine-treated mice had delayed gastric emptying. Dramatic gastric damage included significant disruption of the gastric mucosal cells, a reduced glandular region and increased gastric cell death.
Treatment with naloxone, a synthetic drug that blocks opioids’ receptor function, reduced these effects in the morphine-treated mice, suggesting that classic opiate receptors are involved. Opioid receptors are found in high concentrations in the gastric antrum of the stomach, the lower portion (near the small intestine).
Dr. Roy and co-investigators hypothesized the cytokine IL-6 is involved in the regulation of opioid-induced delay in gastric emptying and gastric damage. Morphine-treated mice had elevated levels of IL-6. Mice that lack IL-6 were treated with morphine, and delays in gastric emptying were reduced. No gastric inflammation was detected in these mice, and pH levels were similar to the placebo group. This demonstrates that an acute increase in IL-6 after morphine treatment causes a delay in gastric emptying, leading to the accumulation of acid and resulting in gastric inflammation.
An important novel finding of this study is that co-administration of the proton pump inhibitor omeprazole with morphine provides gastroprotection by blocking gastric acid secretion, directly reducing gastric delaying and inflammation, and improving morphine tolerance.
The study also addressed an important concern about whether the gastroprotective effect of omeprazole in any way compromises the analgesic effect of morphine. The investigators found that pretreatment resulted in a significant improvement in morphine-induced analgesic tolerance. In previous research they had found that morphine can activate proinflammatory cytokines that drive morphine tolerance. They hypothesize that omeprazole breaks the cycle of chronic morphine tolerance by reducing the level of these cytokines.
“Our studies have clear clinical implications and suggest that omeprazole treatment at the time of morphine administration is a promising, safe, and inexpensive approach for reducing morphine-induced gastrointestinal pathology, improving morphine analgesic tolerance, and prolonging its efficacy as an analgesic agent,” Dr. Roy observed.
Story Source:
Materials provided by Elsevier. Note: Content may be edited for style and length.