VOA标准英语2011--Study: Vitamin D is Powerful Weapon Agai

Study: Vitamin D is Powerful Weapon Against TB

Vitamin D plays a critical role in fighting infection and now scientists say that it may be a powerful weapon against tuberculosis¹.
In a study reported in the journal Science Translational Medicine, researchers studied how T-cells - a kind of white blood cell that fights infection - are especially effective against the bacteria that cause tuberculosis.
People with low vitamin D levels are more susceptible² to infection. It’s also known that people with reduced immunity³ - like those with HIV, the virus that causes AIDS - are more susceptible to tuberculosis.
Robert Modlin, chief of dermatology at the University of California Los Angeles School of Medicine and study co-author says the researchers examined that connection.
“And through that, we discovered that one particular type of T-cell, the one that secreted⁴ a protein called interferon-gamma, was able to activate⁵ white blood cells that were infected with the tuberculosis bacteria to then kill the bacteria.”
But Modlin says it required vitamin D. “People that had low levels of vitamin D in their blood were unable to mount this mechanism⁶ and kill the bacteria.”
In lab experiments, scientists supplemented blood samples that were deficient⁷ in vitamin D. That activated⁸ the T-cells to destroy the TB bacteria.
Modlin says the findings could lead to new therapies using supplements to prevent TB or help in its treatment. “I think it could change how we think about vitamin D supplementation.”
The paper also notes that while the skin absorbs vitamin D naturally from the sun, it takes more exposure for African Americans to reach the same level of vitamin D as white individuals.
But too much sun can lead to skin cancer. So Modlin recommends supplements over sun exposure, while cautioning that high doses can be toxic⁹.
“I recommend that people consult with their internal medicine doctor and perhaps have their vitamin D levels measured if they think that’s appropriate and institute the right supplementation for them.”
Modlin says the next step is to initiate¹⁰ clinical trials to learn whether vitamin D supplements can augment¹¹ resistance to tuberculosis or other infections.

1 tuberculosis   

n.结核病，肺结核

参考例句：

• People used to go to special health spring to recover from tuberculosis.人们常去温泉疗养胜地治疗肺结核。
• Tuberculosis is a curable disease.肺结核是一种可治愈的病。

2 susceptible   

adj.过敏的，敏感的；易动感情的，易受感动的

参考例句：

• Children are more susceptible than adults.孩子比成人易受感动。
• We are all susceptible to advertising.我们都易受广告的影响。

3 immunity   

n.优惠；免除；豁免，豁免权

参考例句：

• The law gives public schools immunity from taxation.法律免除公立学校的纳税义务。
• He claims diplomatic immunity to avoid being arrested.他要求外交豁免以便避免被捕。

4 secreted   

v.（尤指动物或植物器官）分泌( secrete的过去式和过去分词 )；隐匿，隐藏

参考例句：

• Insulin is secreted by the pancreas. 胰岛素是胰腺分泌的。
• He secreted his winnings in a drawer. 他把赢来的钱藏在抽届里。 来自《简明英汉词典》

5 activate   

vt.使活动起来，使开始起作用

参考例句：

• We must activate the youth to study.我们要激励青年去学习。
• These push buttons can activate the elevator.这些按钮能启动电梯。

6 mechanism   

n.机械装置；机构，结构

参考例句：

• The bones and muscles are parts of the mechanism of the body.骨骼和肌肉是人体的组成部件。
• The mechanism of the machine is very complicated.这台机器的结构是非常复杂的。

7 deficient   

adj.不足的，不充份的，有缺陷的

参考例句：

• The crops are suffering from deficient rain.庄稼因雨量不足而遭受损害。
• I always have been deficient in selfconfidence and decision.我向来缺乏自信和果断。

8 activated   

adj. 激活的 动词activate的过去式和过去分词

参考例句：

• The canister is filled with activated charcoal.蒸气回收罐中充满了活性炭。

9 toxic   

adj.有毒的，因中毒引起的

参考例句：

• The factory had accidentally released a quantity of toxic waste into the sea.这家工厂意外泄漏大量有毒废物到海中。
• There is a risk that toxic chemicals might be blasted into the atmosphere.爆炸后有毒化学物质可能会进入大气层。

10 initiate   

vt.开始，创始，发动；启蒙，使入门；引入

参考例句：

• A language teacher should initiate pupils into the elements of grammar.语言老师应该把基本语法教给学生。
• They wanted to initiate a discussion on economics.他们想启动一次经济学讨论。

11 augment   

vt.(使)增大，增加，增长，扩张

参考例句：

• They hit upon another idea to augment their income.他们又想出一个增加收入的办法。
• The government's first concern was to augment the army and auxiliary forces.政府首先关心的是增强军队和辅助的力量。