But his plans face a tough road as pressure grows for big pharmaceutical companies to share their vaccine technologies with poorer nations.WASHINGTON — President Biden, declaring the coronavirus an “all-hands-on-deck crisis,” set out ambitious goals on Wednesday for ending the pandemic and urged world leaders, drug companies, philanthropies and nonprofit groups to embrace a target of vaccinating 70 percent of the world by next year.But the course that Mr. Biden charted, at a virtual Covid-19 summit meeting that he convened on the sidelines of the United Nations General Assembly in New York, may be difficult to turn into reality. And pressure is mounting on the president to lean harder on U.S. pharmaceutical manufacturers, which are resisting sharing their Covid-19 technology with poorer countries.The daylong meeting, the largest gathering of heads of state to address the pandemic, was a reflection of Mr. Biden’s determination to re-establish the United States as a leader in global health after President Donald J. Trump severed ties with the World Health Organization last year, at the outset of the coronavirus crisis.Mr. Biden announced a series of actions, including the purchase of an additional 500 million doses of Pfizer’s vaccine at a not-for-profit price to donate overseas and $370 million to administer the shots. Vice President Kamala Harris announced that the United States would donate $250 million to a new global fund that aims to raise $10 billion to prevent future pandemics.“We’re not going to solve this crisis with half-measures or middle-of-the-road ambitions. We need to go big,” the president said in televised remarks. “And we need to do our part: governments, the private sector, civil society leaders, philanthropists.”Still, Mr. Biden’s summit meeting spurred some resentment toward the United States from those who have criticized the administration for hoarding vaccines and not doing enough to help developing nations manufacture their own. Others said the administration was claiming credit for a plan that already existed.“It’s not really new, but the financial power of what they put on the table is new of course,” Dr. Marie-Paule Kieny, a French virologist and former top W.H.O. official, said in an interview. She noted that the organization had already set a target of vaccinating 70 percent of people in low- and middle-income countries by next September.“The U.S. wants to be engaged,” she added, “but they still don’t know exactly how to engage with the new world that has developed while they were away.”Mr. Biden also faces criticism for offering booster doses to fully vaccinated Americans when millions of people around the world, including health care workers, have yet to receive a first dose. In his speech at the United Nations on Wednesday, President Uhuru Kenyatta of Kenya said that such inequities were hindering efforts to rebuild the global economy, which requires confidence and investment.“The surest way to building that confidence is by making vaccines available to the world, in an equitable and accessible manner,” Mr. Kenyatta said. “That, sadly, is currently not the case. The asymmetry in the supply of vaccines reflects a multilateral system that is in urgent need for repair.”In his opening remarks, Mr. Biden cited two especially urgent challenges: vaccinating the world against Covid-19 and solving a global oxygen shortage, which is leading to unnecessary deaths among Covid-19 patients who might survive if oxygen were more available.But as soon as the president finished speaking and the television cameras were turned off, the director general of the World Health Organization, Dr. Tedros Adhanom Ghebreyesus, called on countries and companies to immediately share doses, intellectual property and technical know-how for manufacturing vaccines, according to one person who attended the summit and took notes on the remarks.President Cyril Ramaphosa of South Africa was equally pointed, the person said. Mr. Ramaphosa called the vaccine inequities “unjust and immoral” and reiterated his proposal that developing countries should be able to manufacture their own doses.More than 4.7 million people around the world, and more than 678,000 in the United States, have died of Covid-19 — a “global tragedy,” Mr. Biden said. While three-quarters of Americans have had at least one coronavirus shot, less than 10 percent of the population of poor nations — and less than 4 percent of the African population — has been fully vaccinated.Worldwide, 79 percent of shots that have been administered have been in high- and upper-middle-income countries, according to the Our World in Data project at the University of Oxford. Covax, the W.H.O.-backed international vaccine initiative, is behind schedule in delivering shots to low- and middle-income nations that need them the most.The United States has pledged to donate 1.1 billion doses of Covid-19 vaccines to low- and middle-income nations.Daniel Irungu/EPA, via ShutterstockAt a briefing held by Physicians for Human Rights this week, Dr. Soumya Swaminathan, the chief scientist of the W.H.O., issued a plea for nations to work together to distribute vaccines in a coordinated and equitable way. She also urged countries to share their excess supplies.“A country-by-country approach, a nationalistic approach, is not going to get us out of this pandemic,” she said. “And that’s where we are today.”.css-1xzcza9{list-style-type:disc;padding-inline-start:1em;}.css-3btd0c{font-family:nyt-franklin,helvetica,arial,sans-serif;font-size:1rem;line-height:1.375rem;color:#333;margin-bottom:0.78125rem;}@media (min-width:740px){.css-3btd0c{font-size:1.0625rem;line-height:1.5rem;margin-bottom:0.9375rem;}}.css-3btd0c strong{font-weight:600;}.css-3btd0c em{font-style:italic;}.css-w739ur{margin:0 auto 5px;font-family:nyt-franklin,helvetica,arial,sans-serif;font-weight:700;font-size:1.125rem;line-height:1.3125rem;color:#121212;}#NYT_BELOW_MAIN_CONTENT_REGION .css-w739ur{font-family:nyt-cheltenham,georgia,’times new roman’,times,serif;font-weight:700;font-size:1.375rem;line-height:1.625rem;}@media (min-width:740px){#NYT_BELOW_MAIN_CONTENT_REGION .css-w739ur{font-size:1.6875rem;line-height:1.875rem;}}@media (min-width:740px){.css-w739ur{font-size:1.25rem;line-height:1.4375rem;}}.css-9s9ecg{margin-bottom:15px;}.css-16ed7iq{width:100%;display:-webkit-box;display:-webkit-flex;display:-ms-flexbox;display:flex;-webkit-align-items:center;-webkit-box-align:center;-ms-flex-align:center;align-items:center;-webkit-box-pack:center;-webkit-justify-content:center;-ms-flex-pack:center;justify-content:center;padding:10px 0;background-color:white;}.css-pmm6ed{display:-webkit-box;display:-webkit-flex;display:-ms-flexbox;display:flex;-webkit-align-items:center;-webkit-box-align:center;-ms-flex-align:center;align-items:center;}.css-pmm6ed > :not(:first-child){margin-left:5px;}.css-5gimkt{font-family:nyt-franklin,helvetica,arial,sans-serif;font-size:0.8125rem;font-weight:700;-webkit-letter-spacing:0.03em;-moz-letter-spacing:0.03em;-ms-letter-spacing:0.03em;letter-spacing:0.03em;text-transform:uppercase;color:#333;}.css-5gimkt:after{content:’Collapse’;}.css-rdoyk0{-webkit-transition:all 0.5s ease;transition:all 0.5s ease;-webkit-transform:rotate(180deg);-ms-transform:rotate(180deg);transform:rotate(180deg);}.css-eb027h{max-height:5000px;-webkit-transition:max-height 0.5s ease;transition:max-height 0.5s ease;}.css-6mllg9{-webkit-transition:all 0.5s ease;transition:all 0.5s ease;position:relative;opacity:0;}.css-6mllg9:before{content:”;background-image:linear-gradient(180deg,transparent,#ffffff);background-image:-webkit-linear-gradient(270deg,rgba(255,255,255,0),#ffffff);height:80px;width:100%;position:absolute;bottom:0px;pointer-events:none;}.css-uf1ume{display:-webkit-box;display:-webkit-flex;display:-ms-flexbox;display:flex;-webkit-box-pack:justify;-webkit-justify-content:space-between;-ms-flex-pack:justify;justify-content:space-between;}.css-wxi1cx{display:-webkit-box;display:-webkit-flex;display:-ms-flexbox;display:flex;-webkit-flex-direction:column;-ms-flex-direction:column;flex-direction:column;-webkit-align-self:flex-end;-ms-flex-item-align:end;align-self:flex-end;}.css-12vbvwq{background-color:white;border:1px solid #e2e2e2;width:calc(100% – 40px);max-width:600px;margin:1.5rem auto 1.9rem;padding:15px;box-sizing:border-box;}@media (min-width:740px){.css-12vbvwq{padding:20px;width:100%;}}.css-12vbvwq:focus{outline:1px solid #e2e2e2;}#NYT_BELOW_MAIN_CONTENT_REGION .css-12vbvwq{border:none;padding:10px 0 0;border-top:2px solid #121212;}.css-12vbvwq[data-truncated] .css-rdoyk0{-webkit-transform:rotate(0deg);-ms-transform:rotate(0deg);transform:rotate(0deg);}.css-12vbvwq[data-truncated] .css-eb027h{max-height:300px;overflow:hidden;-webkit-transition:none;transition:none;}.css-12vbvwq[data-truncated] .css-5gimkt:after{content:’See more’;}.css-12vbvwq[data-truncated] .css-6mllg9{opacity:1;}.css-qjk116{margin:0 auto;overflow:hidden;}.css-qjk116 strong{font-weight:700;}.css-qjk116 em{font-style:italic;}.css-qjk116 a{color:#326891;-webkit-text-decoration:underline;text-decoration:underline;text-underline-offset:1px;-webkit-text-decoration-thickness:1px;text-decoration-thickness:1px;-webkit-text-decoration-color:#326891;text-decoration-color:#326891;}.css-qjk116 a:visited{color:#326891;-webkit-text-decoration-color:#326891;text-decoration-color:#326891;}.css-qjk116 a:hover{-webkit-text-decoration:none;text-decoration:none;}Experts estimate that 11 billion doses are necessary to reach widespread global immunity. Before Wednesday, the United States had promised to donate more than 600 million doses. The additional 500 million that Mr. Biden pledged brings the total U.S. commitment to 1.1 billion doses, more than any other country.“Put another way, for every one shot we’ve administered to pay in America, we have now committed to do three shots to the rest of the world,” Mr. Biden said.But activists, global health experts and world leaders say donated doses will not be enough. They are calling for the Biden administration to do more to scale up global manufacturing of vaccines, particularly in Africa, where the need is greatest.“The Covid-19 pandemic reminds us of the importance of diversification of production centers across the world,” President Joko Widodo of Indonesia, which has suffered one of the biggest surges in cases, said in his General Assembly speech. “We know that no one is safe until everyone is.”The landscape for getting shots into arms has become increasingly challenging since Covax was created in April 2020. Some Asian countries have imposed tariffs and other trade restrictions on Covid-19 vaccines, slowing their delivery. India, home to the world’s largest vaccine maker, has banned coronavirus vaccine exports since April, although officials say they will resume next month.In his opening remarks, Mr. Biden called on other wealthy nations to live up to their donation commitments. He also appeared to take a veiled shot at China, which did not participate in the summit, and has for the most part been selling — rather than donating — its vaccine to other countries.“We should unite around the world on a few principles: that we commit to donating, not selling — donating, not selling — doses to low- and lower-income countries, and that the donations come with no political strings attached,” the president said.He also announced a vaccine partnership with the European Union and said the United States was working to scale up production overseas through a partnership with India, Japan and Australia that was “on track to produce at least 1 billion vaccine doses in India to boost the global supply by the end of 2022.”The doses the Biden administration is donating, however, have been trickling out slowly. So far, 157 million have been shipped overseas. Dr. Peter J. Hotez, an infectious disease expert at Texas Children’s Hospital who helped develop a coronavirus vaccine that is being manufactured in India, said the president should have laid out “a frank articulation of the magnitude” of the shortage.“We don’t need it by 2023,” Dr. Hotez said. “We need it now, over the next six to eight months.”Rick Gladstone

Hairdressers in parts of the UK are reporting clients having new allergic reactions, like rashes and burns, to hair dye after contracting coronavirus. Scientists at Imperial College London are now researching how the disease could be reprogramming our immune system, in a similar way to other illnesses. The trade body that represents hairdressers and beauticians is warning professionals to carry out additional patch tests to avoid facing legal action. Gemma suffered a reaction to a patch test despite using the same hair dye for years. She had also recovered from a previous Covid infection. Her salon says it has seen four clients with the same issue since it began compulsory patch tests for all clients.Reporter: Frankie McCamley

A surprising discovery may offer a promising new direction in the study of multiple sclerosis and other diseases of hypomyelination — when axons of neurons are not covered sufficiently in fatty sheaths (myelin), which disrupts communication between nerve cells.
While investigating potential mechanisms of brain tumor formation, Oren Becher, MD, from Ann & Robert H. Lurie Children’s Hospital of Chicago, and colleagues, found that overexpression of a growth factor receptor (called PDGFRA) in a mouse model did not cause tumors, as anticipated. Instead, they observed severe hypomyelination, which manifested as impaired balance, and hindlimb and tail tremors. Their findings were published in the journal Brain and Behavior.
“Our study provides a new model for studying hypomyelination,” said Dr. Becher, senior author on the study, Rory David Deutsch Malignant Brain Tumor Research Scholar at Lurie Children’s and Associate Professor of Pediatrics, Biochemistry and Molecular Genetics at Northwestern University Feinberg School of Medicine. “Blocking this receptor might prove to be a novel strategy to treat myelination disorders like multiple sclerosis. Of course, more research is needed to confirm our results and explore further.”
Dr. Becher pointed out that the current study focused on prenatal events, which might explain why no tumors were formed, since timing is very important in cancer development.
“We saw that too much PDGFRA interfered with differentiation of progenitor cells that give rise to cells that make myelin,” said Dr. Becher. “These progenitor cells, which continue to be generated throughout the human lifespan, are known to be the cell of origin for brain tumors like diffuse midline glioma. Our findings suggest that the mechanisms we observed might spur brain tumor development at a postnatal stage.”
“I would like to express my profound gratitude to the Rory David Deutsch Foundation and Lurie Children’s for their vision, confidence and support of this research,” said Dr. Becher.
Research at Ann & Robert H. Lurie Children’s Hospital of Chicago is conducted through the Stanley Manne Children’s Research Institute. The Manne Research Institute is focused on improving child health, transforming pediatric medicine and ensuring healthier futures through the relentless pursuit of knowledge. Lurie Children’s is ranked as one of the nation’s top children’s hospitals by U.S. News & World Report. It is the pediatric training ground for Northwestern University Feinberg School of Medicine. Last year, the hospital served more than 220,000 children from 48 states and 49 countries.
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Adults and children with migraines may get less quality, REM sleep time than people who don’t have migraines. That’s according to a meta-analysis published in the September 22, 2021, online issue of Neurology®, the medical journal of the American Academy of Neurology. Children with migraines were also found to get less total sleep time than their healthy peers but took less time to fall asleep.
Rapid Eye Movement (REM) sleep is the stage of sleep that involves the most brain activity and vivid dreams. It is important for learning and memory function.
“Do migraines cause poor sleep quality or does poor sleep quality cause migraines?” said meta-analysis author Jan Hoffmann, MD, PhD, of King’s College London in the United Kingdom and a member of the American Academy of Neurology. “We wanted to analyze recent research to get a clearer picture of how migraines affect people’s sleep patterns and the severity of their headaches. That way, clinicians can better support people with migraines and deliver more effective sleep treatments.”
For the meta-analysis, researchers included 32 studies, involving 10,243 people. Participants completed a questionnaire to rate their own sleep quality. It asked about sleep habits, including how long it takes to fall asleep, total sleep time and the use of sleep aids. Higher scores indicate worse sleep quality.
For many of the studies, people took part in an overnight sleep lab used to diagnose sleep disorders. This sleep study records brain waves, the oxygen level in the blood, heart rate and eye movement.
Researchers found that adults with migraines overall had higher average scores on the questionnaire than people without migraines, with a moderate amount of the difference due to the migraines. The difference was even greater in people with chronic migraines.
When researchers looked at sleep studies, they found adults and children with migraines had less REM sleep as a percentage of their total sleep time than their healthy counterparts.
When looking at children with migraines, researchers found they had less total sleep time, more wake time, and shorter time for sleep onset than children without migraines. Hoffmann said it’s possible children with migraines may fall asleep more quickly than their peers because they may be sleep deprived.
“Our analysis provides a clearer understanding of migraines and how they affect sleep patterns and illustrates the impact these patterns might have on a person’s ability to get a good night’s sleep,” Hoffmann said.
The meta-analysis does not prove a causal relationship between sleep and migraines.
A limitation of the meta-analysis is that medications that affect sleep cycles were not taken into account.
The meta-analysis was supported by the Medical Research Council and the Migraine Trust in the U.K.
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Adults with neurologic conditions are more likely than the general population to have had adverse childhood experiences such as abuse, neglect or household dysfunction, according to a study published in the September 22, 2021, online issue of Neurology® Clinical Practice, an official journal of the American Academy of Neurology. The study does not prove that neurologic conditions are caused by such experiences. It only shows an association between the two.
“Traumatic events in childhood have been linked in previous studies to a higher risk of heart disease, diabetes, riskier health behaviors like smoking and drug use, and decreased life expectancy,” said study author Adys Mendizabal MD, of the University of California Los Angeles and a member of the American Academy of Neurology. “They have also been linked to a higher risk of headaches, but for many other neurologic conditions, little is known. Our study found that people with neurologic conditions like stroke, headache and epilepsy were more likely to have experienced abuse, neglect or household dysfunction as children when compared to the U.S. population.”
The study involved 198 people who were patients at a neurology clinic. Each person completed a questionnaire about adverse childhood experiences and was screened for anxiety and depression. Researchers also looked at medical records to determine how often study participants visited an emergency department, were hospitalized or called their clinic.
Scores for the questionnaire ranged from zero to 10. Scores of four or higher were considered high scores. Researchers compared the prevalence of high scores in the study group of people with neurologic conditions to the estimated prevalence in the U.S. population. They found that within the study group, 24% had elevated scores, compared to 13% of the general population.
After adjusting for age, gender and race/ethnicity, researchers found that study participants with high scores on the questionnaire had high use of healthcare services. They were 21 times more likely than participants with low scores to have high use of emergency department services, with four or more visits in the last year. They were five times more likely to be hospitalized at least three times or more in the last year. And they were three times more likely to call their clinic 15 times or more within the last year. Mendizabal said these findings suggest that people with high numbers of adverse childhood experiences may have more neurologic symptoms, disability or greater medical needs.
In addition to their neurologic condition, participants with high scores were six times more likely to have an additional medical condition and five times more likely to also have a psychiatric condition.
They were also seven times more likely to have high depression scores and four times more likely to have high anxiety scores.
“Early recognition of these high adverse childhood experiences in people with neurologic conditions may be a way to improve their health,” said Mendizabal. “Appropriate referral to social work and behavioral health resources may provide people with support that may reduce their need for health care and improve their neurologic health.”
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When President Biden announced in June that the United States would buy 500 million Pfizer-BioNTech coronavirus vaccine doses for poorer nations, there was a gaping hole in his plan: To fund it, the administration quietly diverted hundreds of millions of dollars that had already been promised to countries for helping to get shots into people’s arms.Mr. Biden did not make the same mistake a second time.His announcement on Wednesday that the United States was donating an additional 500 million Pfizer doses came paired with a promise of an additional $750 million for vaccine distribution, roughly half of it through a nonprofit involved in global vaccinations. That reflected a growing awareness on the part of global leaders that turning vaccines into actual vaccinations represents one of the most significant challenges of this phase of the pandemic.Even so, the Biden administration’s schedule for shipping the newly announced Pfizer doses frustrated activists: Of the 1.1 billion doses that the United States has committed to donations, only 300 million are expected to be shipped this year. The longer the virus circulates around the world, the more dangerous it can become, even for vaccinated people in wealthy countries, scientists have warned.“Purchasing doses for donation sometime next year is helpful, but it does not meaningfully expand the global supply, and it is not justice,” said Peter Maybarduk, the director of the Access to Medicines program at Public Citizen, an advocacy organization.Some experts pleaded for more aggressive action by Mr. Biden to pressure American vaccine makers to share their formulas with nations that desperately need more shots.“Where is the monthly calendar of what each wealthy country is going to deliver?” said Kate Elder, senior vaccines policy adviser for Doctors Without Borders’ Access Campaign. She added, “Where are the announcements about meeting the calls of regions and middle-income countries that are begging to be self-sufficient?”It was not immediately clear how the administration was planning to allocate the new money for vaccine distributions. Some countries have been struggling to train and pay vaccinators and to transport doses. Pfizer doses present especially steep challenges: They must be stored at ultralow temperatures, requiring the installation of freezers and, in many cases, backup generators.Early this year, supply shortages represented the most pressing problem for global vaccinations. Rich nations had raced to secure doses while slow-walking pledges of money and supplies to Covax, the United Nations-backed program to immunize the world.But as those manufacturing difficulties have eased, different problems emerged. One was blatant inequality: More than 5.9 billion shots have been given globally, but overwhelmingly in wealthier nations. Another was that poorer countries had been left without the money needed to move shots from airport tarmacs into people’s arms.Although the Biden administration’s pledges have outpaced those of most Western nations, analysts said other wealthy countries were setting an extraordinarily low bar..css-1xzcza9{list-style-type:disc;padding-inline-start:1em;}.css-3btd0c{font-family:nyt-franklin,helvetica,arial,sans-serif;font-size:1rem;line-height:1.375rem;color:#333;margin-bottom:0.78125rem;}@media (min-width:740px){.css-3btd0c{font-size:1.0625rem;line-height:1.5rem;margin-bottom:0.9375rem;}}.css-3btd0c strong{font-weight:600;}.css-3btd0c em{font-style:italic;}.css-w739ur{margin:0 auto 5px;font-family:nyt-franklin,helvetica,arial,sans-serif;font-weight:700;font-size:1.125rem;line-height:1.3125rem;color:#121212;}#NYT_BELOW_MAIN_CONTENT_REGION .css-w739ur{font-family:nyt-cheltenham,georgia,’times new roman’,times,serif;font-weight:700;font-size:1.375rem;line-height:1.625rem;}@media (min-width:740px){#NYT_BELOW_MAIN_CONTENT_REGION .css-w739ur{font-size:1.6875rem;line-height:1.875rem;}}@media (min-width:740px){.css-w739ur{font-size:1.25rem;line-height:1.4375rem;}}.css-9s9ecg{margin-bottom:15px;}.css-16ed7iq{width:100%;display:-webkit-box;display:-webkit-flex;display:-ms-flexbox;display:flex;-webkit-align-items:center;-webkit-box-align:center;-ms-flex-align:center;align-items:center;-webkit-box-pack:center;-webkit-justify-content:center;-ms-flex-pack:center;justify-content:center;padding:10px 0;background-color:white;}.css-pmm6ed{display:-webkit-box;display:-webkit-flex;display:-ms-flexbox;display:flex;-webkit-align-items:center;-webkit-box-align:center;-ms-flex-align:center;align-items:center;}.css-pmm6ed > :not(:first-child){margin-left:5px;}.css-5gimkt{font-family:nyt-franklin,helvetica,arial,sans-serif;font-size:0.8125rem;font-weight:700;-webkit-letter-spacing:0.03em;-moz-letter-spacing:0.03em;-ms-letter-spacing:0.03em;letter-spacing:0.03em;text-transform:uppercase;color:#333;}.css-5gimkt:after{content:’Collapse’;}.css-rdoyk0{-webkit-transition:all 0.5s ease;transition:all 0.5s ease;-webkit-transform:rotate(180deg);-ms-transform:rotate(180deg);transform:rotate(180deg);}.css-eb027h{max-height:5000px;-webkit-transition:max-height 0.5s ease;transition:max-height 0.5s ease;}.css-6mllg9{-webkit-transition:all 0.5s ease;transition:all 0.5s ease;position:relative;opacity:0;}.css-6mllg9:before{content:”;background-image:linear-gradient(180deg,transparent,#ffffff);background-image:-webkit-linear-gradient(270deg,rgba(255,255,255,0),#ffffff);height:80px;width:100%;position:absolute;bottom:0px;pointer-events:none;}.css-uf1ume{display:-webkit-box;display:-webkit-flex;display:-ms-flexbox;display:flex;-webkit-box-pack:justify;-webkit-justify-content:space-between;-ms-flex-pack:justify;justify-content:space-between;}.css-wxi1cx{display:-webkit-box;display:-webkit-flex;display:-ms-flexbox;display:flex;-webkit-flex-direction:column;-ms-flex-direction:column;flex-direction:column;-webkit-align-self:flex-end;-ms-flex-item-align:end;align-self:flex-end;}.css-12vbvwq{background-color:white;border:1px solid #e2e2e2;width:calc(100% – 40px);max-width:600px;margin:1.5rem auto 1.9rem;padding:15px;box-sizing:border-box;}@media (min-width:740px){.css-12vbvwq{padding:20px;width:100%;}}.css-12vbvwq:focus{outline:1px solid #e2e2e2;}#NYT_BELOW_MAIN_CONTENT_REGION .css-12vbvwq{border:none;padding:10px 0 0;border-top:2px solid #121212;}.css-12vbvwq[data-truncated] .css-rdoyk0{-webkit-transform:rotate(0deg);-ms-transform:rotate(0deg);transform:rotate(0deg);}.css-12vbvwq[data-truncated] .css-eb027h{max-height:300px;overflow:hidden;-webkit-transition:none;transition:none;}.css-12vbvwq[data-truncated] .css-5gimkt:after{content:’See more’;}.css-12vbvwq[data-truncated] .css-6mllg9{opacity:1;}.css-qjk116{margin:0 auto;overflow:hidden;}.css-qjk116 strong{font-weight:700;}.css-qjk116 em{font-style:italic;}.css-qjk116 a{color:#326891;-webkit-text-decoration:underline;text-decoration:underline;text-underline-offset:1px;-webkit-text-decoration-thickness:1px;text-decoration-thickness:1px;-webkit-text-decoration-color:#326891;text-decoration-color:#326891;}.css-qjk116 a:visited{color:#326891;-webkit-text-decoration-color:#326891;text-decoration-color:#326891;}.css-qjk116 a:hover{-webkit-text-decoration:none;text-decoration:none;}And even as countries have promised to donate more doses, they have been slow to follow through, with the World Health Organization saying that only 15 percent of promised donations have been delivered. The W.H.O. has set a target of vaccinating 40 percent of every country’s population this year, requiring wealthy nations to share doses significantly more quickly.There remains considerable excess supply: Wealthy nations will have 1 billion more vaccines than they need by the end of 2021, even if they administer booster shots, according to Airfinity, a science analytics company.Global health officials have urged wealthy nations to let go of those supplies before they expire. Some countries have donated vaccines so close to their expiration dates, and in such small quantities, that poorer countries have struggled to use them.Some 11 billion doses are needed globally, and activists said on Wednesday that the wealthy world’s response remained far too piecemeal. The new Pfizer doses purchased by the U.S. will be shipped through Covax starting in January.

Dietary restriction is arguably the most promising non-genetic method of extending lifespan and healthspan in many model organisms, including mammals. While researchers scramble to develop interventions that would mimic the benefits of dietary restrictions in humans (who generally have a hard time maintaining Spartan diets), the work from the lab of Buck professor Pankaj Kapahi, PhD, suggests that the benefits of dietary restriction often vary among individuals and even in tissues within those individuals. He and his colleagues are challenging the field to change their approach to dietary restriction and aim for precise, individualized interventions. In a review published in Cell Metabolism, they provide a framework for a sub-specialty dubbed precision nutrigeroscience, based on biomarkers affected by genetics, gender, tissue, and age.
“Everyone is hoping for a ‘one size fits all’ intervention when it comes to diet, and work in our lab and several others show that this is simply not going to be the case,” says Kapahi, whose team aims to understand the mechanisms by which nutrient signaling and metabolism influence aging and age-related diseases. “I’ve had to change the way I look at aging. A lot of us get very deep into the minutia of understanding what I call two-dimensional biological pathways, and we are forgetting a whole other dimension which is that these pathways are different in each individual, and within tissues in individual bodies. Context matters and we can’t make real progress in this field without including that. We will end up hurting the field because eventually interventions won’t work and then people will get disappointed.”
Studies in genetically distinct strains of fruit flies showed the need for precision-nutrition
In 2020, Buck postdoc Kenneth Wilson, PhD, who is the first author of this review, did a genome-wide analysis of 160 genetically distinct strains of the fruit fly D. melanogaster that ate the same Spartan diet. Publishing in Current Biology, heand his team showed that lifespan and healthspan were not linked under dietary restriction. While 97 percent of strains showed some lifespan or healthspan extension on the limited diet, only 50 percent showed a significantly positive response to dietary restriction for both. Thirteen percent of the strains were more vigorous, yet died sooner with dietary restriction; 5 percent lived longer but spent more time in poor health. The remaining 32 percent of the strains showed no benefits or detriments to lifespan or healthspan, or negative responses to both.
“I think it’s important for everyone in the field to understand and appreciate that there are a lot of different ways to look at what an intervention might be doing. You might see a response in one case, but that response might not work in another strain of the same species,” says Wilson. “Conversely if you’re not seeing something, that doesn’t mean that the intervention you’re testing doesn’t work, it just means you’re not using the right model for that intervention.” Wilson says it is also crucial that researchers be aware of the possible disconnect between extending lifespan and healthspan when it comes to diet. “I think the last thing any of us want to do is give people more years of ill health.”
What the review includes
The review provides a detailed primer covering several forms of dietary restriction (from caloric restriction to various forms of intermittent fasting as well as diets that restrict proteins, carbohydrates, specific amino acids, micronutrients, and metabolites) and details related effects in yeast, worms, flies, and mice. Researchers explain nutrient-sensing mechanisms such as IGF-1-like signaling, TOR, and AMPK. They discuss metabolic reprogramming regulators including sirtuins and NAD as well as circadian clock regulators. They include the mediating effects of fat and lipid metabolism, proteostasis and autophagy, and the reduction of cellular senescence as well as mitochondrial function.

Mathematical modeling of disease spread suggests that herd immunity could be achieved with fewer vaccine doses by using Bluetooth-based contact-tracing apps to identify people who have more exposure to others — and targeting them for vaccination. Mark Penney, Yigit Yargic and their colleagues from the Perimeter Institute for Theoretical Physics in Ontario, Canada, present this approach in the open-access journal PLOS ONE on September 22, 2021.
The COVID-19 pandemic has raised questions about how to best allocate limited supplies of vaccines for the greatest benefit against a disease. Mathematical models suggest that vaccines like those available for COVID-19 are most effective at reducing transmission when they are targeted to people who have more exposure to others. However, it can be challenging to identify such individuals.
Penney and colleagues hypothesized that this challenge could be addressed by harnessing existing apps that anonymously alert users to potential COVID-19 exposure. These apps use Bluetooth technology to determine the duration of contact between any pair of individuals who both have the same app downloaded on their smart phones. The researchers wondered whether this technology could also be used to help identify and target vaccines to those with greater exposure — a strategy analogous to a wildfire-fighting practice called “hot-spotting,” which targets sites with intense fires.
To explore the effectiveness of a hot-spotting approach to vaccination, Penney and colleagues used mathematical modeling to simulate how a disease would spread among a population with such a strategy in place. Specifically, they applied an analytical technique borrowed from statistical physics known as percolation theory.
The findings suggest that a Bluetooth-based hot-spotting approach to vaccination could reduce the number of vaccine doses needed to achieve herd immunity by up to one half. The researchers found improvements even for simulations in which relatively few people use contact-tracing apps — a situation mirroring reality for COVID-19 in many regions.
In the future, the modeling approach used for this study could be refined, such as by incorporating the effects of strains on the healthcare system. Nonetheless, the researchers note, the new findings highlight a technically feasible way to implement a strategy that previous research already supports.
The authors add: “The technology underlying digital contact tracing apps has made it possible to implement novel decentralized and efficient vaccine strategies.”
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Has the scent of freshly baked chocolate chip cookies ever taken you back to afternoons at your grandmother’s house? Has an old song ever brought back memories of a first date? The ability to remember relationships between unrelated items (an odor and a location, a song and an event) is known as associative memory.
Psychologists began studying associative memory in the 1800s, with William James describing the phenomenon in his 1890 classic The Principles of Psychology. Scientists today agree that the structures responsible for the formation of associative memory are found in the medial temporal lobe, or the famous “memory center” of the brain, but the particular cells involved, and how those cells are controlled, have remained a mystery until now.
Neuroscientists at the University of California, Irvine have discovered specific types of neurons within the memory center of the brain that are responsible for acquiring new associative memories. Additionally, they have discovered how these associative memory neurons are controlled. We rely on associative memories in our everyday lives and this research is an important step in understanding the detailed mechanism of how these types of memories are formed in the brain.
“Although associative memory is one of the most basic forms of memory in our everyday life, mechanisms underlying associative memory remain unclear” said lead researcher Kei Igarashi, faculty fellow of the Center for the Neurobiology of Learning and Memory and assistant professor of anatomy & neurobiology at the UCI School of Medicine.
The study published today in the journal Nature, reports for the first time, that specific cells in the lateral entorhinal cortex of the medial temporal lobe, called fan cells, are required for the acquisition of new associative memories and that these cells are controlled by dopamine, a brain chemical known to be involved in our experience of pleasure or reward.
In the study, researchers used electrophysiological recordings and optogenetics to record and control activity from fan cells in mice as they learn to associate specific odors with rewards. This approach led researchers to discover that fan cells compute and represent the association of the two new unrelated items (odor and reward). These fan cells are required for successful acquisition of new associative memories. Without these cells, pre-learned associations can be retrieved, but the new associations cannot be acquired. Additionally acquiring new associations also requires dopamine.
“We never expected that dopamine is involved in the memory circuit. However, when the evidence accumulated, it gradually became clear that dopamine is involved,” said Igarashi. “These experiments were like a detective story for us, and we are excited about the results.”
This discovery is an important piece in the puzzle of understanding how memories are formed in the brain and lays a foundation on which other researchers can continue to build. Associative memory abilities are known to decline in neurodegenerative diseases like Alzheimer’s Disease. Understanding the neurobiological mechanism of how these memories are formed is the first step to developing therapeutics to slow the loss of associative memory abilities in Alzheimer’s Disease.
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To break down toxic proteins more quickly, immune cells in the brain can join together to form networks when needed. This is shown by a joint study of the University of Bonn, the German Center for Neurodegenerative Diseases (DZNE) and the Institut François Jacob in France. However, in certain mutations that can cause Parkinson’s disease, this cooperation is impaired. The findings are published in the journal Cell.
The protein alpha-synuclein (abbreviated aSyn) performs important tasks in the nerve cells of the brain. But under certain circumstances, aSyn molecules can clump together and form insoluble aggregates. These damage the neurons; they are for instance typically found in the brains of people suffering from Parkinson’s disease or Lewy body dementia.
The immune cells of the brain, the microglial cells, therefore try to break down and dispose of the aSyn aggregates. This process is not only time-consuming; it can also cause the microglial cells themselves to perish. “We have now identified a mechanism that addresses both problems,” explains Prof. Dr. Michael Heneka. The researcher is director of the Department of Neurodegenerative Diseases and Geriatric Psychiatry at the University Hospital Bonn and conducts research there and at the DNZE on neurodegenerative diseases such as Parkinson’s and Alzheimer’s disease.
Division of labor prevents overload
The research suggests that microglial cells may spontaneously join together in order to better cope with threats. For this purpose, they form tube-like projections that dock onto neighboring microglial cells. These connections are then used to distribute the aSyn aggregates among the partners in the network. Without this division of labor, individual immune cells would have to shoulder a major part of the degradation work and would be overwhelmed.
Joining forces prevents that from happening. However, the connecting tubes also serve another purpose: Microglial cells can use them to give their neighbors a boost when they are in too much distress or indeed in mortal danger. “They then send mitochondria to neighboring cells that are busy breaking down the aggregates,” explains Heneka’s colleague Dr. Hannah Scheiblich. “Mitochondria function like little power plants; so they provide extra energy to the stressed cells.”
In certain mutations, which are found more frequently in Parkinson’s disease patients, both aSyn and mitochondrial transport are impaired. A similar situation applies to another disease in which the degradation of aSyn is impaired: Lewy body dementia. Researchers have isolated certain immune cells, the macrophages, from blood samples of affected individuals. These can be converted into microglia-like cells with the help of specific regulatory molecules. “These were still able to form networks in the lab. However, the transport of aSyn through the connecting tubes was severely impaired,” says Heneka, who is also a member of the Cluster of Excellence Immunosensation2 and the transdisciplinary research area “Life & Health.”
Findings may open up new therapeutic perspectives
The fact that microglial cells can join together was previously unknown. “We have opened the door to a field that will certainly engage researchers for many years to come,” Heneka emphasizes. In the medium term, this may also open up new therapeutic perspectives for neurological disorders such as Parkinson’s disease or dementia.
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