美国英语听力80篇2 Lesson30

（单词翻译）

[00:04.57]A new American study shows that chemicals used to kill insects in the home may increase the risk of developing Parkinson's disease.
[00:17.14]Earlier studies have shown that people who work around pesticides¹ are at greater risk of developing the disease.
[00:26.25]But scientists say the latest study is the first to link the'disease to the use of pesticides in the home.
[00:35.42]Parkinson's is a disease of the central nervous system.
[00:40.88]It causes the loss of a chemical in the brain called dopamine.
[00:46.68]As the disease progresses, it causes the muscles to become hard and difficult to move.
[00:54.23]It also causes the arms and legs to shake.
[00:58.70]Scientists at Stanford University in California studied about 500 people from northern California who have Parkinson's disease.
[01:11.47]The people were asked detailed² questions about past use of pesticides and other chemicals in their homes or outdoor gardens.
[01:22.52]This information from the Parkinson's patients was compared with information from more than 500 people who did not have the disease.
[01:34.09]Researchers found that the people who were exposed to pesticides
[01:39.68]were more than two times as likely to develop Parkinson's disease as those who were not exposed to the chemicals.
[01:48.96]Scientists say exposure to pesticides in the home was linked to the highest risk of developing the disease.
[01:58.88]People who used pesticides in their outdoor gardens were not found to be at greater risk for Parkinson's.
[02:08.16]It is not clear why pesticides may increase the risk of Parkinson's disease.
[02:15.55]Scientists say some chemical compounds may target and kill cells in some parts of the brain.
[02:24.69]Damage to nerve cells in a part of the brain called the substantia nigra leads to signs of Parkinson's disease.
[02:34.31]Lorene Nelson is the leading researcher of the Study.
[02:40.68]She presented the findings earlier this month at the yearly meeting of the American Academy of Neurobiology in San Diego,California.
[02:51.08]She says chemicals in the environment may cause the death of some brain cells.
[02:59.04]But she says it is too early to suggest that people change their use of pesticides.
[03:06.85]Ms Nelson says more studies are needed before scientists can know for sure what causes Parkinson's disease.