科技英语小短文-3 (2010-03-03 11:49:15)
标签： 杂谈
Fat mice give clue to drug against obesity (2003)
A chemical switch that tells cells when to burn fat and when to store it has been discovered in mice, paving the way for new drugs that could one day be used to control obesity and cholesterol.
Scientists at the Salk Institute in La Jolla, California, have identified a receptor in mouse cells that supervises how fat is used in the body and influences the ease with which mice put on weight.
If a similar regulator exists in human beings, which is likely, it would be a promising target for drugs that stimulate the burning of fat to fight the developed world's growing obesity epidemic. Genes that carry the blueprint for receptor, PPARd, could also help to explain why some people seem to eat what they like and remain thin, while others find that every extra calorie goes straight on to the waistline.
Experiments revealed that when PPARd was stimulated, mice used up fat deposits and lost weight, while mice with low PPARd activity were prone to obesity.
Mice with a highly active version weighed about 20 per cent less than normal mice at birth, and 35 per cent less at the age of one. The active receptor also protected mice against obesity when fed a high-calorie and high-fat diet. The findings are published today in the journal Cell.
科学家近日在老鼠体内发现一种化学变化，能够表明细胞在什么时候燃烧脂肪，又在什么时候对脂肪进行储存。这一发现也许能够帮助人们进一步研制控制脂肪和胆固醇的药品。
加利福尼亚拉霍拉沙克研究所的科学家发现在老鼠的细胞中有一种感受体，负责调度分配体内的脂肪，当老鼠因为安逸而体重增加时，这一感受提也能发挥相应的作用。
如果在人类体内也能有这样一种调节器，或者利用药物来达到调节的目的，也许就能解决全球范围内愈演愈烈的肥胖问题了。构成这一名为PPARd的感受体的基因的存在，也能从某种程度上解释为什么有的人并不忌口却仍能保持身材，而有的人却仿佛摄入的所有热量都立刻囤积在了腰上。
实验显示，当PPARd受到刺激，老鼠就会消耗体内囤积的脂肪，从而使体重下降。而PPARd不活跃的老鼠则比较肥胖。
体内这一物质活跃的老鼠在出生时体重就比普通老鼠轻约20%，到一岁时则要轻35%左右。体内感受体活跃的老鼠即便吃大量高热量高脂肪的食物，也不容易发胖。这一研究结果刊登在4月18日的《细胞》杂志上。
Lots of Fruit in Childhood Cuts Adult Cancer Risk
Adults who had been fed plenty of fruit when they were children are less likely to suffer from certain types of cancer, British scientists said on Wednesday.
A medical study of nearly 4,000 men and women showed that the more fruits the adults had eaten when they were young the less likely they were to suffer from lung, bowel and breast cancer.
"This study shows that childhood fruit consumption may have a long term protective effect on cancer risk in adulthood," Dr. Maria Maynard of the Medical Research Council in London said.
All of the adults in the study had filled in a food inventory during the 1930s for a research study looking into the eating habits of families in rural and urban areas of England and Scotland. Maynard and her colleagues studied the medical records of the group up to July 2000, by which time 483 cases of cancer had been diagnosed. In addition to fewer cases of cance, a high consumption of fruit was associated with a lower death rate from all causes.
Fruits are loaded with antioxidants, vitamins and other nutrients, which can help to prevent genetic damage that can lead to the development of cancer.
The scientists also studied the impact of vitamins C, E and beta carotene on cancer but they did not find any evidence that individual antioxidants were as protective as fruit.
英国科学家19日研究发现：童年时多吃水果，长大以后患某些癌症的几率会被降低。
科学家对4千名男女进行了跟踪调查，发现童年时水果吃得越多，越不容易得肺癌、肠癌和乳腺癌。
伦敦医学研究会的玛利亚·梅纳德博士说："这一研究表明，孩提时代多食用水果将在成年以后产生长期的防癌作用。"
接受调查的所有人都曾在20世纪30年代填写过一份英格兰和苏格兰城市及农村家庭饮食状况的调查表。而梅纳德和她的同事对这些人进行了跟踪调查，发现到2000年6月，其中的483人被诊断患了癌症。研究人员发现：孩提时代摄入水果量越高的人越不容易得癌症，而患上癌症的人群中，水果摄入量高的，抗病的时间也越长。
水果富含抗氧化剂、维他命和其他营养成分，可以有效防止身体机能发生癌变。
科学家还研究了维生素C、维生素E和β胡萝卜素对癌症的抵抗作用，但他们没有找到任何证据显示单一的抗氧化剂能比水果更有效。
Quality sleep 'rescues memories'
Even facts "forgotten" by people during a busy day may be retrieved if this is followed by a good night's sleep.
Researchers from the University of Chicago asked volunteers to remember simple words.
Many found their memories letting them down towards the end of the day, but the following morning, those who had slept well could recall much more.
Researchers, writing in the journal Nature, said the brain could "rescue" lost memories during the night.
When the brain is first asked to remember something, that memory is laid down in an "unstable" state, meaning that it is possible that it could be lost.
At some point, the brain consolidates those it deems important into a "stable", more permanent state.
However, the Chicago researchers suggested that it was possible for a "stable" memory to be made "unstable" again.
This would mean that memories could be modified then filed away again in the face of new experiences.
The 12 volunteers tested in the experiment were played words created through a speech synthesizer which were purposely difficult to understand.
Initially, the written version of the word was available, but afterwards the volunteers were asked to identify the word from the audio version only.
Tests revealed that the ability to recall the right word tended to tail off as the day ended.
However, when the volunteers were retested after a good night's sleep, they were able to recall some words that they had "forgotten" the previous evening.
Dr Daniel, one of the study authors, said: "Sleep consolidates memories, protecting them against subsequent interference or decay.
"Sleep also appears to 'recover' or restore memories."
He said: "If performance is reduced by decay, sleep might actively recover what has been lost."
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