VOA慢速英语2013 New Vaccine Shrinks Head and Neck Cancers

（单词翻译）

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.