Tag: 上海龙凤 shlf 77

Seventeen volunteers let this worm live inside them to help defeat a dangerous disease

Seventeen volunteers let this worm live inside them to help defeat a dangerous disease

first_img At 2:15 p.m., Roestenberg huddles in a small meeting room with three colleagues. The worms are not drugs, but they need to be released for use just like an experimental drug would be. The scientists check numbers on some documents against data on a computer screen, then they sign a form. The experiment can begin.Twenty minutes later, back in the infection room, the volunteers stretch out their arms so that a little metal cylinder, a few centimeters in diameter, can be taped to their skin. Carefully, an assistant pipettes a few drops of water, containing exactly 20 parasites, into each cylinder. The volunteers are nervous, but they say they are motivated. “I like the fact that the study is related to vaccines, because I’ve worked in that field before,” says one, a young scientist. The woman next to him says she comes from East Africa and knows the disease firsthand. They will also be paid €1000 for their time.Once infected, the volunteers will return to the lab every week so the research team can test their blood for a molecule called CAA, which the worms regurgitate from their stomachs. CAA’s presence will indicate that the worms are still alive; in future trials, its absence might mean that a vaccine or drug has worked.Some schistosomiasis scientists agree that the potential benefits justify the minimal risks. “My hope is that it would hugely accelerate identification of worthwhile candidate vaccines,” says Alison Elliott of the London School of Hygiene & Tropical Medicine, who works at a joint Ugandan and U.K. research unit in Entebbe. She is interested in establishing the model there; people in Uganda, a country badly affected by schistosomiasis, might react differently to a vaccine if they were exposed to the worms in childhood, she explains. At a recent stakeholders’ meeting, “Ethics and regulatory colleagues were very supportive of taking discussions of the model forward, and community representatives are already keen for the opportunity to volunteer!” Elliott added in an email.“It’s itching a little bit,” one of the Leiden volunteers says 5 minutes into the exposure. After half an hour, when the infested water is removed from the volunteers’ forearms, red spots reveal where the parasites have entered their new hosts. Then, close to 4 p.m., the clock stops ticking; the volunteers head home and Roestenberg and her colleagues go out for a coffee. 3 2 By Kai KupferschmidtFeb. 21, 2018 , 4:25 PM At 12:05 p.m. on a Thursday in February, a lab technician takes a six-well plate containing a solitary red snail and places it in a heated water bath under a strong light. The light and warmth signal hundreds of tiny larval parasites to stream out of the mollusk. Now, the clock starts ticking for Meta Roestenberg, an infectious disease physician here at Leiden University Medical Center. She has about 4 hours to launch a unique, controversial experiment in which she will let the parasites burrow into the arms of four healthy volunteers. If she waits too long, the larvae start to die.Roestenberg and her colleagues are infecting people with Schistosoma mansoni, one of five tiny waterborne worm species that cause schistosomiasis, a disease that sickens millions of people in Africa, the Middle East, and Latin America and kills thousands each year. There is no schistosomiasis vaccine and only one old, inadequate drug, praziquantel, to treat it. Infecting humans could help speed up the development of new interventions. Roestenberg has designed the experiment to prevent the parasites from reproducing, and she says the risk to volunteers is extremely low.But not low enough, some scientists argue, because there is no guarantee that subjects will get rid of their parasites when the study is over. “I would not volunteer for this study and if I had a son or daughter who wanted to volunteer, I would recommend against it,” says Daniel Colley, a schistosomiasis researcher at the University of Georgia in Athens.Sign up for our daily newsletterGet more great content like this delivered right to you!Country *AfghanistanAland IslandsAlbaniaAlgeriaAndorraAngolaAnguillaAntarcticaAntigua and BarbudaArgentinaArmeniaArubaAustraliaAustriaAzerbaijanBahamasBahrainBangladeshBarbadosBelarusBelgiumBelizeBeninBermudaBhutanBolivia, Plurinational State ofBonaire, Sint Eustatius and SabaBosnia and HerzegovinaBotswanaBouvet IslandBrazilBritish Indian Ocean TerritoryBrunei DarussalamBulgariaBurkina FasoBurundiCambodiaCameroonCanadaCape VerdeCayman IslandsCentral African RepublicChadChileChinaChristmas IslandCocos (Keeling) IslandsColombiaComorosCongoCongo, The Democratic Republic of theCook IslandsCosta RicaCote D’IvoireCroatiaCubaCuraçaoCyprusCzech RepublicDenmarkDjiboutiDominicaDominican RepublicEcuadorEgyptEl SalvadorEquatorial GuineaEritreaEstoniaEthiopiaFalkland Islands (Malvinas)Faroe IslandsFijiFinlandFranceFrench GuianaFrench PolynesiaFrench Southern TerritoriesGabonGambiaGeorgiaGermanyGhanaGibraltarGreeceGreenlandGrenadaGuadeloupeGuatemalaGuernseyGuineaGuinea-BissauGuyanaHaitiHeard Island and Mcdonald IslandsHoly See (Vatican City State)HondurasHong KongHungaryIcelandIndiaIndonesiaIran, Islamic Republic ofIraqIrelandIsle of ManIsraelItalyJamaicaJapanJerseyJordanKazakhstanKenyaKiribatiKorea, Democratic People’s Republic ofKorea, Republic ofKuwaitKyrgyzstanLao People’s Democratic RepublicLatviaLebanonLesothoLiberiaLibyan Arab JamahiriyaLiechtensteinLithuaniaLuxembourgMacaoMacedonia, The Former Yugoslav Republic ofMadagascarMalawiMalaysiaMaldivesMaliMaltaMartiniqueMauritaniaMauritiusMayotteMexicoMoldova, Republic ofMonacoMongoliaMontenegroMontserratMoroccoMozambiqueMyanmarNamibiaNauruNepalNetherlandsNew CaledoniaNew ZealandNicaraguaNigerNigeriaNiueNorfolk IslandNorwayOmanPakistanPalestinianPanamaPapua New GuineaParaguayPeruPhilippinesPitcairnPolandPortugalQatarReunionRomaniaRussian FederationRWANDASaint Barthélemy Saint Helena, Ascension and Tristan da CunhaSaint Kitts and NevisSaint LuciaSaint Martin (French part)Saint Pierre and MiquelonSaint Vincent and the GrenadinesSamoaSan MarinoSao Tome and PrincipeSaudi ArabiaSenegalSerbiaSeychellesSierra LeoneSingaporeSint Maarten (Dutch part)SlovakiaSloveniaSolomon IslandsSomaliaSouth AfricaSouth Georgia and the South Sandwich IslandsSouth SudanSpainSri LankaSudanSurinameSvalbard and Jan MayenSwazilandSwedenSwitzerlandSyrian Arab RepublicTaiwanTajikistanTanzania, United Republic ofThailandTimor-LesteTogoTokelauTongaTrinidad and TobagoTunisiaTurkeyTurkmenistanTurks and Caicos IslandsTuvaluUgandaUkraineUnited Arab EmiratesUnited KingdomUnited StatesUruguayUzbekistanVanuatuVenezuela, Bolivarian Republic ofVietnamVirgin Islands, BritishWallis and FutunaWestern SaharaYemenZambiaZimbabweI also wish to receive emails from AAAS/Science and Science advertisers, including information on products, services and special offers which may include but are not limited to news, careers information & upcoming events.Required fields are included by an asterisk(*) Worms mature, mate, and lay eggs. Parasites to the people Researchers have long grown Schistosoma mansoni in the lab, using hamsters. Now, they are also infecting humans with the parasitic worms. Larvae emerge from snail. 1 EYE OF SCIENCE/SCIENCE SOURCE 4center_img Male and female larvae are used to infect hamster. 5 In nature, male and female Schistosoma mansoni worms pair up within the host. Studies in which people are purposely infected with malaria, cholera, and flu are on the rise, but they haven’t been done with schistosomiasis, in part because damage from the S. mansoni eggs can be irreversible. The goal of the current study, which began in early 2017, is to find out whether Roestenberg’s infection model is safe; if so, she hopes to test a vaccine later this year.At 1:35 p.m., Roestenberg walks to the room where the volunteers will be infected. She opens a transparent plastic container that contains epinephrine, antihistamines, and corticosteroids. “This is the emergency box,” she says—in case a subject has a strong allergic reaction. None of the 13 volunteers infected so far has, although one who was infected with 30 larvae developed a strong fever. In another precaution, the volunteers have been tested to rule out risk factors such as HIV infection and pregnancy. In nature, people become infected with both male and female parasites, but Roestenberg uses only males, so there will be no eggs and thus, she says, no symptoms. And when the study ends in 12 weeks, the volunteers will be given praziquantel to cure them.That drug, Colley emphasizes, is “not terribly effective.” But Roestenberg says that even if it fails, volunteers needn’t worry. “The ethics board asked me: ‘If one worm survives even after multiple treatments, what will happen to that person?’ And I said: ‘They’ll probably live to be 100.’” The board gave her its blessing. Colley agrees the risk is low, but still, S. mansoni has an average life span of 5 to 10 years. “That is a long time to have something as ugly as a schistosome living in your blood vessels, putting out excrement and things.” At 1:05 p.m., the technician takes the plate out of the bath. The larvae are ready to be harvested. Viewed under a microscope, they move around frantically, like minipropellers. Another technician removes one drop, dilutes it, adds iodine to kill the parasites, and counts them. That allows the researchers to calculate how many are left in the well: 574. They need only 80 today, 20 per volunteer.A snail population in an African lake could shed millions of these larvae into the water on a single day, each equipped with a chemical sensor that lets it home in on humans entering the water. After penetrating the skin, they migrate to the liver, where they mature and mate. Male-female couples stay together and move to blood vessels in the bowel, where they can reside for years, shedding hundreds of eggs a day. Most eggs end up in urine and feces, and if they make their way back into the lake they may infect fresh snails. But some get trapped in the liver, kidneys, or spleen, causing damage and leading to pain, blood loss, malnutrition, and sometimes death.Researchers in this same lab recreated the parasite’s life cycle decades ago, with hamsters taking the place of humans. That allowed them to produce and study S. mansoni. Now, Roestenberg wants to bring humans back into the mix. Field trials, especially of vaccines, are hugely expensive and complex, and the risk of failure is considerable. A controlled infection study can act as a gatekeeper, she says: “It gives you an indication whether something can work in humans or not.”  Male larvae are allowed to burrow into arm ofvolunteer. N. DESAI/SCIENCE Eggs are harvested from liver and used to infect snails. Seventeen volunteers let this worm live inside them to help defeat a dangerous diseaselast_img read more

Are Anushka Sharma and Virat Kohli planning their first child

Are Anushka Sharma and Virat Kohli planning their first child

first_imgVirat Kohli and Anushka Sharma planning their first child?InstagramAnushka Sharma has reportedly been distancing herself from any movie offers, giving rise to speculations that the actress and her hubby Virat Kohli are planning to have their first baby.According to reports, Anushka, who was last seen in Zero that was released in December 2018, has been getting a lot of movie offers, but she refused all of those. As reported, she was offered to play the female lead in Satte Pe Satta remake, but she seemed to be reluctant to accept it as well.Speculations of Anushka planning to have a child got momentum as she reportedly has not signed any film post Zero, which was a flop. However, it may also be the case that Anushka is currently willing to spend some quality time with Virat, or simply wait for the right project to land in her kitty.Earlier, rumours of Anushka being pregnant had made headlines many a times, but all of those had turned out to be false. After similar rumours had started doing the rounds, the NH10 actress had expressed annoyance at it while confirming those to be false.”People can keep speculating (about someone being pregnant), and then after four months when they realise that these stories are false, they will feel silly and say, ‘Let’s go after the other one who got married, let’s talk about her now’! This is done to generate news. There is absolutely no truth to it and it’s not something that’s being planned in the near future,” she had told a publication.Virat and the gorgeous actress had tied the knot in 2017 in a private ceremony in Italy. It was one of the most beautiful and talked about celebrity weddings in India. Close Celebrities Who Announced They Were Pregnant In 2018last_img read more

Fuselage of crashed Indonesia plane believed to be found

Fuselage of crashed Indonesia plane believed to be found

first_imgFamilies of passengers of Lion Air flight JT610 stand as they look at the belongings of the passengers at Tanjung Priok port in Jakarta, Indonesia, on 31 October 2018. ReutersIndonesian search and rescue workers believe they have found the fuselage of a Lion Air passenger jet that crashed with 189 people on board, and are also trying to confirm the origin of an underwater “ping” signal, officials said on Wednesday.Ground staff lost touch with flight JT610 of Indonesian budget airline Lion Air 13 minutes after the Boeing 737 MAX 8 took off early on Monday from Jakarta, on its way to the tin-mining town of Pangkal Pinang.There were no survivors.Indonesia’s military chief said he believed the plane had been located, and a transport safety official said divers would be sent to confirm the origin of a “ping” signal picked up by a search and rescue team late on Tuesday.“We strongly believe that we have found a part of the fuselage,” armed forces chief Hadi Tjahjanto told broadcaster TV One.Speaking on board the navy ship KRI Rigel, navy official Colonel Haris Djoko Nugroho told broadcaster TVOne that a 22-metre long object had been found in waters about 32 metres deep, and a sonar was being used to identify it.Divers would also be sent to check, he said.The Rigel has been searching in an area about 5 nautical miles from the site where the aircraft lost contact.The accident is the first to be reported involving the widely sold Boeing 737 MAX, an updated, more fuel-efficient version of the manufacturer’s single-aisle jet.The plane’s blackboxes, as the cockpit voice recorder and flight data recorder are known, should help explain why the almost-new jet went down minutes after take-off.Amid media speculation over the airworthiness of the aircraft, the transport minister suspended Lion Air’s technical director and several technicians to facilitate the crash investigation.The suspended technicians “issued the recommendations for that flight”, the ministry said in a press release. It did not say how many technicians had been suspended.QuestionsAn official of the national transport safety panel has said the plane had technical problems on its previous flight on Sunday, from the city of Denpasar on the resort island of Bali, including an issue over “unreliable airspeed”.Privately owned Lion Air, founded in 1999, said the aircraft had been in operation since August and was airworthy. The pilot and co-pilot had 11,000 hours of flying time between them, it said.Lion Air chief executive Edward Sirait has acknowledged reports of technical problems with the aircraft, but said maintenance had been carried out “according to procedure” before it was cleared for flight again.Investigators are looking into why the pilot had asked to return to base shortly after take-off, a request that ground control officials had granted, although the flight crashed soon after.They will also question pilots who flew the same aircraft from Bali to Jakarta on Sunday.For details of search, crash inquiry, please click onThe airline is to meet a team from Boeing on Wednesday to discuss the fate of the plane.Although it is now almost certain that everyone on the plane died, relatives are desperate to find traces of their loved ones. Only body parts and debris have been found.last_img read more

Trump to extend China trade deadline meet Xi soon

Trump to extend China trade deadline meet Xi soon

first_imgDonald TrumpUS president Donald Trump said on Friday there was “a very good chance” the United States would strike a deal with China to end their trade war and that he was inclined to extend his 1 March tariff deadline and meet soon with Chinese president Xi Jinping.US and Chinese negotiators had made progress and will extend this week’s round of negotiations by two days through Sunday, Trump told reporters at the White House as he met with his top negotiators and their counterpart, Chinese Vice Premier Liu He.”I think that we both feel there’s a very good chance a deal will happen,” Trump said.Liu agreed there had been “great progress”.”From China, we believe that (it) is very likely that it will happen and we hope that ultimately we’ll have a deal. And the Chinese side is ready to make our utmost effort,” he said at the White House.The Republican president said he probably would meet with Xi in March in Florida to decide on the most important terms of a trade deal.Extending the deadline would put on hold Trump’s threatened tariff increase to 25 per cent from 10 per cent on $200 billion of Chinese imports into the United States. That would prevent a further escalation in a trade war that already has disrupted commerce in goods worth hundreds of billions of dollars, slowed global economic growth and roiled markets.Optimism that the two sides will find a way to end the trade war lifted stocks, especially technology shares. The S&P 500 stock index reached its highest closing level since 8 November Oil prices rose to their highest since mid-November, with Brent crude reaching a high of $67.73 a barrel.Currency AgreementTrump and treasury secretary Steven Mnuchin said the two sides had reached an agreement on currency. Trump declined to provide details, but US officials long have expressed concerns that China’s yuan is undervalued, giving China a trade advantage and partly offsetting US tariffs.Announcement of a pact aimed at limiting yuan depreciation was putting “the currency cart before the trade horse,” but would likely be positive for Asian emerging market currencies, said Alan Ruskin, global head of currency strategy at Deutsche Bank in New York. “How can you agree to avoid excessive Chinese yuan depreciation or volatility if you have not made an agreement on trade that could have huge FX implications?” Ruskin asked in a note to clients.In a letter to Trump read aloud by an aide to Liu at the White House, Xi called on negotiators to work hard to strike a deal that benefits both country.Trump said a deal with China may extend beyond trade to encompass Chinese telecommunications companies Huawei Technologies and ZTE Corp .The Justice Department has accused Huawei of conspiring to violate US sanctions on Iran and of stealing robotic technology from T-Mobile US Inc.Chinese peer ZTE was last year prevented from buying essential components from US firms after pleading guilty to similar charges, crippling its operations.Memorandums No MoreTrump appeared at odds with his top negotiator, US trade representative Robert Lighthizer, on the preliminary terms that his team is outlining in memorandums of understanding for a deal with China. Trump said he did not like MOUs because they are short term, and he wanted a long-term deal.”I don’t like MOUs because they don’t mean anything,” Trump said. “Either you are going to make a deal or you’re not.”Lighthizer responded testily that MOUs were binding, but that he would never use the term again.Reuters reported exclusively on Wednesday that the two sides were drafting the language for six MOUs covering the most difficult issues in the trade talks that would require structural economic change in China.Negotiators have struggled this week to agree on specific language within those memorandums to address tough US demands, according to sources familiar with the talks. The six memorandums include cyber theft, intellectual property rights, services, agriculture and non-tariff barriers to trade, including subsidies.An industry source briefed on the talks said both sides have narrowed differences on intellectual property rights, market access and narrowing a nearly $400 billion US trade deficit with China. But bigger differences remain on changes to China’s treatment of state-owned enterprises, subsidies, forced technology transfers and cyber theft of US trade secrets.Lighthizer pushed back when questioned on forced technology transfers, saying the two sides made “a lot of progress” on the issue, but did not elaborate.The United States has said foreign firms in China are often coerced to transfer their technology to Chinese firms if they want to operate there. China denies this.The US Chamber of Commerce on Friday urged the US government to ensure the deal was comprehensive and addressed core issues, rather than one based on more Chinese short-term purchases of goods.China has pledged to increase purchases of agricultural produce, energy, semiconductors and industrial goods to reduce its trade surplus with the United States.China committed to buying an additional 10 million tonnes of US soybeans on Friday, US Agriculture Secretary Sonny Perdue said on Twitter. China bought about 32 million tonnes of US soybeans in 2017.The commitments are a “show of good faith by the Chinese” and “indications of more good news to come,” Perdue wrote.China was the top buyer of US soybeans before the trade war, but Beijing’s retaliatory tariffs on US soybeans slashed business that had been worth $12 billion annually.last_img read more