The Ames Test offered a fast and inexpensive way to identify carcinogens, leading to the banning of chemicals linked to cancer and birth defects.Bruce Nathan Ames, a biochemist who discovered a revolutionary method of detecting potential carcinogens, paving the way for the banning of many commonly used chemicals, died on Oct. 5 in Berkeley, Calif. He was 95.His wife, Giovanna Ferro-Luzzi Ames, said his death, in a hospital, was from complications after a fall.The so-called Ames Test, developed in the 1970s, is still used by drug manufacturers and pesticide companies to check the safety of their products. It involves exposing chemicals to a mutant strain of salmonella bacteria that Dr. Ames created; how the bacteria responds to a chemical makes it possible to determine whether that chemical caused DNA damage and therefore might lead to cancer in humans.In an America increasingly concerned about the effects of pollution and industrial chemicals, the test offered a quick, inexpensive alternative to animal testing, which was so prohibitively expensive that regulators were able to test only a fraction of chemicals on the market.“It changed the regulatory sphere,” said Angela Creager, a science historian at Princeton University who is writing a book about the Ames Test. “It showed that it was actually possible to get toxicity information on every chemical if we wanted to.”After capturing the attention of the national press, Dr. Ames remained in the spotlight as he used the Ames Test to expose the toxicity of a number of commonplace chemicals.We are having trouble retrieving the article content.Please enable JavaScript in your browser settings.Thank you for your patience while we verify access. If you are in Reader mode please exit and log into your Times account, or subscribe for all of The Times.Thank you for your patience while we verify access.Already a subscriber? Log in.Want all of The Times? Subscribe.

When scientists win the Nobel Prize in Physiology or Medicine, they typically thank family and colleagues, maybe their universities or whoever funded their research.This year, as the molecular biologist Gary Ruvkun accepted the most prestigious award of his career, he spent a few minutes lauding his experimental subject: a tiny worm named Caenorhabditis elegans, which he called “badass.”“No one ever thought to use that term for a worm,” he said during a news conference. “We are asserting ourselves now, and I was asserting this before the Nobel-stinking-Prize.”This isn’t the worm’s first brush with international stardom, nor is it the first time C. elegans has been thanked for aiding award-winning work. Dr. Ruvkun’s award was actually the fourth Nobel Prize resulting from C. elegans research, cementing the lowly soil worm’s outsize role in scientific discovery.The one-millimeter nematode has helped scientists understand how healthy cells are instructed to kill themselves and how the process goes awry in AIDS, strokes and degenerative diseases. (That work was the subject of the 2002 Nobel Prize in Physiology or Medicine.)Self-proclaimed “worm people” were recognized by the Nobel committee in 2006 for discovering gene silencing, which became the basis for an entirely new class of drugs. Two years later, the chemistry prize went to scientists who used nematodes to help invent cellular “lanterns” that allowed biologists to see the inner workings of a cell.We are having trouble retrieving the article content.Please enable JavaScript in your browser settings.Thank you for your patience while we verify access. If you are in Reader mode please exit and log into your Times account, or subscribe for all of The Times.Thank you for your patience while we verify access.Already a subscriber? Log in.Want all of The Times? Subscribe.

The S.E.C. alleged shortcomings in research said to support the drug, and its developer agreed to a $40 million settlement. Some experts wonder why clinical trials have not been stopped.A drug touted by a small pharmaceutical company as a treatment for Alzheimer’s disease has had a turbulent bid for regulatory approval.Studies that once seemed to support the drug, simufilam, have been called into question, leading to retractions from scientific journals and resignations of top officials at Cassava Sciences, the company sponsoring it.In September, the Securities and Exchange Commission brought charges against Cassava Sciences, alleging that the company had made misleading statements about the results of clinical trial data. The S.E.C. also charged a Cassava consultant researcher for manipulating research results.Cassava Sciences agreed to a $40 million settlement with regulators to resolve the case; the company neither admitted nor denied wrongdoing.Yet to the consternation of some dementia experts, simufilam remains in advanced clinical trials. “If the efficacy and the underlying data is being questioned, which it is, why would you continue the study?” said George Perry, an Alzheimer’s researcher at the University of Texas at San Antonio.While some important results have been challenged, the company maintains there are still research and clinical results that suggest the drug may yet prove valuable.We are having trouble retrieving the article content.Please enable JavaScript in your browser settings.Thank you for your patience while we verify access. If you are in Reader mode please exit and log into your Times account, or subscribe for all of The Times.Thank you for your patience while we verify access.Already a subscriber? Log in.Want all of The Times? Subscribe.

The birth defects were more likely, but still very uncommon, in infants conceived through certain fertility treatments, a large study found.Major heart defects are more common — but still rare — in babies conceived through certain fertility treatments, including in vitro fertilization, researchers reported on Thursday in the largest study of its kind.The research, which included medical records of more than seven million Nordic children, also bolstered evidence that I.V.F. is associated with a small but significant uptick in birth abnormalities.“It’s an increased risk, but the absolute risk is very small,” said Dr. Ulla-Britt Wennerholm, the senior author of the paper and a professor of obstetrics and gynecology at the University of Gothenburg in Sweden.“I think that’s a reassuring finding, actually.”The study focused on children born between 1984 and 2015 in Denmark, Sweden, Norway and Finland as a result of a class of fertility treatments called assisted reproductive technology, the most common of which is I.V.F.The risk of a major heart defect was about 36 percent higher in this group than in children who were naturally conceived. But the defects were still uncommon: Less than 2 percent of infants conceived through A.R.T. were born with major heart defects.The risk of heart defects didn’t change based on whether the parents underwent I.C.S.I., a procedure in which sperm is injected into an egg, or I.V.F., which allows the sperm to penetrate the egg naturally in a lab dish.We are having trouble retrieving the article content.Please enable JavaScript in your browser settings.Thank you for your patience while we verify access. If you are in Reader mode please exit and log into your Times account, or subscribe for all of The Times.Thank you for your patience while we verify access.Already a subscriber? Log in.Want all of The Times? Subscribe.

Overwhelmed by queries, physicians are turning to artificial intelligence to correspond with patients. Many have no clue that the replies are software-generated.Every day, patients send hundreds of thousands of messages to their doctors through MyChart, a communications platform that is nearly ubiquitous in U.S. hospitals.They describe their pain and divulge their symptoms — the texture of their rashes, the color of their stool — trusting the doctor on the other end to advise them. But increasingly, the responses to those messages are not written by the doctor — at least, not entirely. About 15,000 doctors and assistants at more than 150 health systems are using a new artificial intelligence feature in MyChart to draft replies to such messages.Many patients receiving those replies have no idea that they were written with the help of artificial intelligence. In interviews, officials at several health systems using MyChart’s tool acknowledged that they do not disclose that the messages contain A.I.-generated content.The trend troubles some experts who worry that doctors may not be vigilant enough to catch potentially dangerous errors in medically significant messages drafted by A.I.In an industry that has largely used A.I. to tackle administrative tasks like summarizing appointment notes or appealing insurance denials, critics fear that the wide adoption of MyChart’s tool has allowed A.I. to edge into clinical decision-making and doctor-patient relationships.We are having trouble retrieving the article content.Please enable JavaScript in your browser settings.Thank you for your patience while we verify access. If you are in Reader mode please exit and log into your Times account, or subscribe for all of The Times.Thank you for your patience while we verify access.Already a subscriber? Log in.Want all of The Times? Subscribe.

In a new study, many people doubted or abandoned false beliefs after a short conversation with the DebunkBot.Shortly after generative artificial intelligence hit the mainstream, researchers warned that chatbots would create a dire problem: As disinformation became easier to create, conspiracy theories would spread rampantly.Now, researchers wonder if chatbots might also offer a solution.DebunkBot, an A.I. chatbot designed by researchers to “very effectively persuade” users to stop believing unfounded conspiracy theories, made significant and long-lasting progress at changing people’s convictions, according to a study published on Thursday in the journal Science.Indeed, false theories are believed by up to half of the American public and can have damaging consequences, like discouraging vaccinations or fueling discrimination.The new findings challenge the widely held belief that facts and logic cannot combat conspiracy theories. The DebunkBot, built on the technology that underlies ChatGPT, may offer a practical way to channel facts.“The work does overturn a lot of how we thought about conspiracies,” said Gordon Pennycook, a psychology professor at Cornell University and author of the study.Until now, conventional wisdom held that once someone fell down the conspiratorial rabbit hole, no amount of arguing or explaining would pull that person out.We are having trouble retrieving the article content.Please enable JavaScript in your browser settings.Thank you for your patience while we verify access. If you are in Reader mode please exit and log into your Times account, or subscribe for all of The Times.Thank you for your patience while we verify access.Already a subscriber? Log in.Want all of The Times? Subscribe.

Americans are already turning to A.I. for health information in large numbers, new research suggests.Susan Sheridan had heard of ChatGPT but had never used it, so the first question she asked the artificial intelligence chatbot was a bit garbled: “Facial droop, facial pain and dental work.”She had turned to ChatGPT in a moment of desperation. The right side of her face was sagging, she tripped over words as she spoke and her head hurt so much that she couldn’t rest her head on the pillow.A day earlier, when her husband first noticed the drooping, the couple drove three hours to an emergency room, only for the doctor to send her home after labeling her symptoms as benign.ChatGPT disagreed. One potential explanation for her symptoms, the chatbot told her, was Bell’s palsy, which needed urgent treatment to avoid lasting damage.She made another trip to the emergency room, where a doctor confirmed the chatbot’s suspicions and gave her steroids and antivirals. As a result, she was mostly cured.“I don’t want to replace doctors — I believe in the doctor-patient relationship, I believe in the health care system,” said Ms. Sheridan, 64, co-founder of a patient safety advocacy organization.We are having trouble retrieving the article content.Please enable JavaScript in your browser settings.Thank you for your patience while we verify access. If you are in Reader mode please exit and log into your Times account, or subscribe for all of The Times.Thank you for your patience while we verify access.Already a subscriber? Log in.Want all of The Times? Subscribe.

Seven million pounds of Boar’s Head meats have been recalled since late July, when reports of serious illnesses and deaths began to occur.In the last month, nine people have died and dozens have been hospitalized in a listeria outbreak linked to Boar’s Head deli meats that has led to a recall of seven million pounds of its products.The outbreak has been traced back to a Boar’s Head plant in Jarratt, Va., where federal inspectors had documented repeated problems. The inspections records show that they found black mold, water dripping over meat and dead flies.The plant has been temporarily shut down in the wake of the outbreak. But reports of illnesses and deaths have continued to accumulate, prompting public health officials to issue more warnings to consumers to ensure they discard certain Boar’s Head lunch meats that may still be in their refrigerators.Here’s what you should know.What is listeria?Listeria monocytogenes is a bacteria that can be deadly. The largely food-borne Listeria illness can be contracted through foods like contaminated deli meats and unpasteurized milk products, according to the Mayo Clinic.People may also fall ill by touching a listeria-laden surface before touching their mouths.Federal public health experts said the Boar’s Head case was the worst listeria outbreak since 2011, when tainted cantaloupe killed 33 people and hospitalized at least 143.Anyone can become sick from the bacteria, but it is most likely to cause severe illness in pregnant women, adults older than 65 and people with weakened immune systems.We are having trouble retrieving the article content.Please enable JavaScript in your browser settings.Thank you for your patience while we verify access. If you are in Reader mode please exit and log into your Times account, or subscribe for all of The Times.Thank you for your patience while we verify access.Already a subscriber? Log in.Want all of The Times? Subscribe.

Recent infections from the Eastern equine encephalitis virus are worrying health officials. Severe cases can be deadly or leave lasting injuries.Residents of 10 communities in Massachusetts have been warned to stay indoors from dusk to dawn. Some local parks are closed at night. A person in New Hampshire has died. Pesticides are being sprayed from trucks and aircrafts.What’s causing all of the alarm? A mosquito-borne virus called Eastern equine encephalitis, which is so rare that most infectious disease experts might never see a case. This year, at least four states have reported human E.E.E. infections.Here’s what you should know.Is this an unusually bad year for E.E.E.?The virus is endemic in North America, which means that it’s consistently present on the continent. The United States sees a handful of infections every year, mainly along the East Coast and around the Great Lakes. In 2019, there were a record 38 cases, the largest U.S. outbreak in recent history.As of Tuesday, the Centers for Disease Control and Prevention had reported four human cases, in Wisconsin, New Jersey, Massachusetts and Vermont. In addition, officials in New Hampshire have reported one death.But experts say it’s too soon to know whether this will turn out to be a particularly severe year. Mosquito-borne illnesses usually spread widely until around October, or when it’s cold enough for water to freeze, said Dr. Jonathan Abraham, a clinical infectious disease specialist at Harvard Medical School.Until then, health officials in the affected areas are urging residents to take precautions.Who should worry?The main risk factor for contracting the virus is exposure to mosquitoes, said Dr. Cameron Wolfe, a professor of infectious diseases at the Duke University School of Medicine.We are having trouble retrieving the article content.Please enable JavaScript in your browser settings.Thank you for your patience while we verify access. If you are in Reader mode please exit and log into your Times account, or subscribe for all of The Times.Thank you for your patience while we verify access.Already a subscriber? Log in.Want all of The Times? Subscribe.

Dr. Michael Blaiss, an allergist at the Medical College of Georgia, was often surprised by how hesitant his patients were to use their auto-injectors, syringe-like devices like the EpiPen that deliver a drug needed to head off potentially fatal allergic reactions.Some patients called his office, on the verge of shock, to double-check that it was necessary to give themselves the shot. Others told him they would rather wait in the emergency room parking lot to “see what happens.”Children suffering dangerous reactions sometimes ran away from their parents, terrified of the needle. One Tom-and-Jerry-like chase ended with a father getting mistakenly injected, Dr. Blaiss recalled.A new device recently approved by the Food and Drug Administration may help quell some of the anxiety. The device, Neffy, administers epinephrine, the drug in the EpiPen, through a nasal spray rather than a needle.“We have needed this for so long,” Dr. Blaiss said. “I truly believe it will save lives.”Patient advocates and allergists, who regularly see the consequences of needle aversion, have been awaiting an auto-injector alternative for years. Among the general population, this fear is relatively common — most children and up to 30 percent of young adults are afraid of needles, according to one systematic review.Ilana Golant, founder and chief executive of the Food Allergy Fund, said she knew parents who had been so nervous to give the shot that they had missed the window to stave off a serious reaction, landing their child in the hospital.We are having trouble retrieving the article content.Please enable JavaScript in your browser settings.Thank you for your patience while we verify access. If you are in Reader mode please exit and log into your Times account, or subscribe for all of The Times.Thank you for your patience while we verify access.Already a subscriber? Log in.Want all of The Times? Subscribe.