2006年VOA标准英语-Scientists Develop Vaccine Against Weight Gain

By Jessica Berman
Washington
31 July 2006
 
It could be the dream of anyone who has spent years trying to lose weight. Scientists have developed a vaccine¹ that causes and maintains weight loss. So far, the drug has only been tested in rats. But researchers say it has the potential to help millions of obese² people worldwide who are at risk for early death.

---------

  
  
As anyone who has tried to lose a significant amount of weight knows, it can be hard to do.

In 1999, scientists found out why. They discovered ghrelin, a growth hormone³ that regulates appetite and energy metabolism⁴. When people cut back on calories to try to lose weight, levels of ghrelin increase dramatically to maintain existing fat stores. It's the body's way of preventing starvation. Ghrelin drops when eating returns to normal.

Since the discovery, researchers have been trying to find a way to manipulate ghrelin so people can lose weight.

Diagram of how vaccine works (Photo courtesy Michael Meijler)   
  
A team of researchers led by Kim Janda at Scripps Research Institute in La Jolla, California have taken a novel approach to harnessing ghrelin. Janda says they made a vaccine that prompts the body's immune system to attack ghrelin as if it were bacteria.

"And so what we had to do was make molecules⁵ such that the immune system was in a sense tricked into recognizing ghrelin as being foreign, and thus bind⁶ to it and not allow it to get to the central nervous system and get to the hypothalamus where it can impart its properties," he explained.

Researchers developed three versions of the vaccine and applied⁷ them to rats, which were given the same amount of food and drink. Janda says two of them showed promise.

The rats in this study were a normal weight. In the future, Janda says, researchers plan to look at how well the vaccine works on obese rats.

"I think what this does is it shows a new avenue of research," he said. "I'm not saying it's going to be a cure all to everything. But it will put (make) people start thinking about using this type of approach for treating a problem that's basically become an epidemic⁸."

  
  
Janda says he could rush the vaccine through the approval process within a year but first wants to make sure it is safe.

The article, "Vaccination⁹ against weight gain," is published in the journal proceedings¹⁰ of the National Academy of Sciences.

1 vaccine   

n.牛痘苗，疫苗；adj.牛痘的，疫苗的

参考例句：

• The polio vaccine has saved millions of lives.脊髓灰质炎疫苗挽救了数以百万计的生命。
• She takes a vaccine against influenza every fall.她每年秋季接种流感疫苗。

2 obese   

adj.过度肥胖的，肥大的

参考例句：

• The old man is really obese,it can't be healthy.那位老人确实过于肥胖了，不能算是健康。
• Being obese and lazy is dangerous to health.又胖又懒危害健康。

3 hormone   

n.荷尔蒙，激素，内分泌

参考例句：

• Hormone implants are used as growth boosters.激素植入物被用作生长辅助剂。
• This hormone interacts closely with other hormones in the body.这种荷尔蒙与体內其他荷尔蒙紧密地相互作用。

4 metabolism   

n.新陈代谢

参考例句：

• After years of dieting,Carol's metabolism was completely out of whack.经过数年的节食，卡罗尔的新陈代谢完全紊乱了。
• All living matter undergoes a process of metabolism.生物都有新陈代谢。

5 molecules   

分子( molecule的名词复数 )

参考例句：

• The structure of molecules can be seen under an electron microscope. 分子的结构可在电子显微镜下观察到。
• Inside the reactor the large molecules are cracked into smaller molecules. 在反应堆里，大分子裂变为小分子。

6 bind   

vt.捆，包扎；装订；约束；使凝固；vi.变硬

参考例句：

• I will let the waiter bind up the parcel for you.我让服务生帮你把包裹包起来。
• He wants a shirt that does not bind him.他要一件不使他觉得过紧的衬衫。

7 applied   

adj.应用的；v.应用，适用

参考例句：

• She plans to take a course in applied linguistics.她打算学习应用语言学课程。
• This cream is best applied to the face at night.这种乳霜最好晚上擦脸用。

8 epidemic   

n.流行病；盛行；adj.流行性的，流传极广的

参考例句：

• That kind of epidemic disease has long been stamped out.那种传染病早已绝迹。
• The authorities tried to localise the epidemic.当局试图把流行病限制在局部范围。

9 vaccination   

n.接种疫苗，种痘

参考例句：

• Vaccination is a preventive against smallpox.种痘是预防天花的方法。
• Doctors suggest getting a tetanus vaccination every ten years.医生建议每十年注射一次破伤风疫苗。

10 proceedings   

n.进程，过程，议程；诉讼(程序)；公报

参考例句：

• He was released on bail pending committal proceedings. 他交保获释正在候审。
• to initiate legal proceedings against sb 对某人提起诉讼