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New Vaccine1 Shrinks Head and Neck Cancers
From VOA Learning English, this is SCIENCE IN THE NEWS, in Special English. I’m Bob Doughty2.
And I’m June Simms. Today, we tell about a new vaccine for fighting cancers in the head and neck. We tell about progress in the fight against malaria3. And we report on evidence suggesting that being able to speak two languages is good for the brain as we age.
Scientists are developing a new vaccine to treat cancers of the head and neck. The new vaccine is reported to be most effective as a nasal spray, entering the body as a watery4 mist through the nose. The treatment is one of a growing number of vaccines5 in the past few years to fight cancer.
When a person develops cancer, the body’s natural defenses for fighting disease launch an attack against the cancer cells. But the natural defenses are often too weak to prevent the cells from spreading.
So, scientists have been working to develop vaccines to improve the natural defenses against the cancer cells. Two promising6 vaccines in human tests target prostate cancer and metastatic melanoma, the deadliest form of skin cancer.
Another experimental vaccine is designed to treat solid tumors that form in the mucosal tissues. Those tissues are found in the head, neck, lungs and reproductive organs. They produce a thick fluid containing powerful chemicals that normally protect against infection. However, they also block the immune cells that are supposed to fight the cancerous tumors.
Now, researchers have developed a nasal spray vaccine that can cancel out this resistance. The vaccine is able to activate8 and energize9 an immune cell called a CD8+ T-cell in the tissue at the tumor7.
French researcher Eric Tartour led a team studying the effectiveness of the intranasal spray on solid mucosal tumors in mice. He says the tumors developed after the animals were infected with human papilloma virus -- a virus known to cause cancer.
“The tumor shrank. And we analyzed10 the tumors when they shrank. And they are heavily infiltrated11 by immune cells which destroyed the tumors.”
He and his team compared the effectiveness of their vaccine, both as a nasal spray and when it was injected. They found the vaccine worked better as a spray.
Eric Tartour works with the Universitie Paris Descarte. He and his team have been developing the intranasal vaccine for five years. He says their next goal is to see how well it works against tumors that have spread to other areas in the body.
A report on the anti-cancer spray was published in the journal Science Translational Medicine.
There is good news in the fight to save children from the most serious kind of malaria, known as cerebral12 malaria. Each year, cerebral malaria infects about 500 thousand young people in African countries south of the Sahara Desert. They get the disease after being bitten by a common insect, the mosquito.
Cerebral malaria causes the brain and spinal13 tissues of its victims to swell14 or expand. Many children die. Others develop memory problems and have learning difficulties.
Recently, scientists in the United States and Brazil discovered that the drug lovastatin may help. The drug is normally used to lower cholesterol15 levels in the blood.
Guy Zimmerman works at the University of Utah School of Medicine in Salt Lake City. He and his research team performed tests on a group of mice infected with the disease. Half of the animals were given chloroquine, a well-known malaria drug. The other half also received lovastatin.
“The mice that got the anti-malarial16 drug and the lovastatin had a significantly reduced incident of the late brain dysfunction.”
Lovastatin is one of many drugs that limit how the body’s natural defenses against disease react to infection. A certain amount of swelling17 is expected when a person is sick. But sometimes there is too much swelling, and the body begins to harm itself.
Dr. Zimmerman suggests that lovastatin be used in the treatment of sepsis, also known as blood poisoning. It, like cerebral malaria, sickens and kills many people around the world each year.
Researchers have asked American health officials to act quickly to approve lovastatin for malarial patients. But they know that many tests will need to be done in many parts of Africa where the disease causes so much misery18.
Details of this study can be found in the journal “PLOS Pathogens.”
Next, we have a “bad news” “good news” story. The World Health Organization reports that malaria kills about 660,000 people around the world each year. The good news is the number of deaths has dropped 30 percent over the past 10 years because of progress in treatment and prevention.
The aid group Doctors Without Borders is providing the latest drugs to rural medical centers in Mali. In some areas, the infection rate dropped 65 percent in only a week. One mother of three young children says she saw a fast improvement in their health. She says her children often had higher than normal body temperatures in the past. But with the new medicines, they are much improved.
The World Health Organization fears that there will not be enough money to keep this kind of medical program operating. In 2011, international donors19 offered more than two billion dollars to fight malaria. That is less than half of what the WHO says is needed each year.
Some of the money goes for simple, but effective tools. Sir Brian Greenwood is with the London School of Hygiene20 and Tropical Medicine.
“One of those is the humble21 bed net which people have been using for hundreds of years. But the relatively22 new advance has been in treating the nets with insecticide. Now, the insecticide is actually incorporated into the material.”
The bed nets and insecticide products keep mosquitos from biting people while they sleep. Malaria is caused by small organisms carried by the mosquito. Over time, these parasites23 have begun to develop resistance to some anti-malarial drugs.
Professor Greenwood says he has seen this in Cambodia, and thinks the same thing is happening in other Southeast Asian countries.
“Fortunately, not yet in Africa. But it would be a disaster if those parasites got loose in Africa, and our main treatment was failing again, like it did with chloroquin.”
Researchers say it is important for donors to continue to provide money for treatment. At this time, there is no drug that can keep people from becoming infected.
Finally, a new study has added to evidence suggesting that being bilingual is good for the brain. In the study, older adults who have spoken two languages since childhood showed better mental skills than those who speak just one language.
Earlier studies showed that bilingualism seemed to favor the development of these heightened skills. Organizers of the new study say their findings provide evidence of that cognitive24 advantage among older, bilingual adults.
In the study, the researchers asked people to sort colors and shapes in a series of simple exercises. They used brain imaging to compare how well three groups of people switched among these exercises. The groups were bilingual seniors, monolingual seniors and younger adults.
The imaging showed different patterns of activity in the frontal part of the brain, in an area used for processing such tasks.
Brian Gold is a neuroscientist at the University of Kentucky College of Medicine. He was also the lead author of the study.
“We found that seniors who are bilingual are able to activate their brain with a magnitude closer to young subjects. So they don’t need to expend25 as much effort, and yet they still out-perform their monolingual peers, suggesting they use their brain more efficiently26.”
He says that knowing a second language made no difference for the young adults. They did better at the exercises than both groups of older people. But he says the older bilingual adults appear to have built up a kind of surplus from a lifetime of increased mental activity.
He says his findings confirm an earlier study on bilingualism among patients with Alzheimer's disease. That study showed that bilingual speakers developed more damage, but were able to think at the same level as patients with less damage.
Dr. Gold says he believes the new study confirms that bilingualism can play a protective role in the brain. He now plans to study whether learning a second language or immigrating27 to another country as an adult can provide some of the same mental advantages as lifelong bilingualism.
The study appeared in the Journal of Neuroscience.
收听单词发音 |
1
vaccine
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| n.牛痘苗，疫苗；adj.牛痘的，疫苗的 | |
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doughty
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| adj.勇猛的，坚强的 | |
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malaria
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| n.疟疾 | |
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watery
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| adj.有水的，水汪汪的；湿的，湿润的 | |
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vaccines
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| 疫苗，痘苗( vaccine的名词复数 ) | |
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promising
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| adj.有希望的，有前途的 | |
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tumor
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| n.（肿）瘤，肿块(英)tumour | |
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activate
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| vt.使活动起来，使开始起作用 | |
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energize
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| vt.给予(某人或某物)精力、能量 | |
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analyzed
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| v.分析( analyze的过去式和过去分词 )；分解；解释；对…进行心理分析 | |
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infiltrated
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| adj.[医]浸润的v.（使）渗透，（指思想）渗入人的心中( infiltrate的过去式和过去分词 ) | |
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cerebral
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| adj.脑的，大脑的；有智力的，理智型的 | |
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spinal
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| adj.针的，尖刺的，尖刺状突起的；adj.脊骨的，脊髓的 | |
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swell
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| vi.膨胀，肿胀；增长，增强 | |
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cholesterol
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| n.（U）胆固醇 | |
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malarial
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| 患疟疾的，毒气的 | |
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swelling
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| n.肿胀 | |
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misery
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| n.痛苦，苦恼，苦难；悲惨的境遇，贫苦 | |
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donors
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| n.捐赠者( donor的名词复数 )；献血者；捐血者；器官捐献者 | |
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hygiene
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| n.健康法，卫生学 （a.hygienic） | |
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humble
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| adj.谦卑的，恭顺的；地位低下的；v.降低，贬低 | |
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relatively
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| adv.比较...地，相对地 | |
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parasites
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| 寄生物( parasite的名词复数 )； 靠他人为生的人； 诸虫 | |
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cognitive
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| adj.认知的，认识的，有感知的 | |
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expend
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| vt.花费，消费，消耗 | |
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efficiently
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| adv.高效率地，有能力地 | |
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immigrating
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| v.移入( immigrate的现在分词 )；移民 | |
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