英语资料

Science and technology
Animal testing
Be nice to mice
and they may return the favour
ONLY one drug of every ten successfully tested in laboratory animals ends up
working in people.
One reason, of course, is that mice are not men.

Another, though, might have to do with the fact that whereas human patients
are afforded all manner of creature comforts, their animal proxies are not.

Although medical science's favourite critters relish temperatures of a little over
30°C, laboratories routinely keep them at five or ten degrees below that.
This is not in order to torture the beasts but, rather, because when kept warm
they are unmanageably aggressive.
The downside is that they have to eat more than they otherwise would, in order
to keep their bodies warm.
That changes their physiology.
And that in turn alters the way they metabolise drugs, with possibly confusing
results.
Joseph Garner, of Stanford University, thinks the answer is to keep the labs
cool,
but let mice cope with the low temperatures as they do in their natural habitat:
not by eating more but by building nests.
So far, though, no one has a clear idea of how much nesting material is needed
to keep mice happy.
Dr Garner and his colleagues therefore decided to find out.
They have just reported their results in the Public Library of Science.
Dr Garner and his team let each of their mice, 36 males and as many females
from three strains commonly used in trials, roam free in two cages connected by
a narrow tube.
One cage was kept constant at one of six temperatures between 20°C and 35°C.
The other was maintained at 20°C but was stocked with up to ten grams of
finely shredded paper, which the mice could use to weave a nest.
The idea was to check whether the animals would rather build a nest in the
cooler cage or move to the warmer one, possibly tugging nesting material along
with them strand by strand.
The researchers found that the rodents' preferences varied slightly between
strains, as well as between sexes, confirming that there is no single set of
conditions in which all mice feel cosy.
In general, though, with little nesting material around, the animals laboriously
carried strands of paper over to the warmer spot, one or two at a time.
But leave at least six grams of paper in the chilly cage, and many mice will
prefer instead to brave the cold and build a nest there.
That seems a small price to pay for better drug trials.
科学技术
动物实验
善待小鼠
或许它们会报以恩情
在动物实验中测试成功的药物中仅仅有十分之一最终被用于人类。
其中一个原因显然是老鼠与人有本质的不同。
另一个原因则是人类患者会得到无微不至的照顾与舒适的环境，而被用于实验的动物则不
会。
药物科学中饲养动物的最适温度略高于30°C，然而，在实验室中，它们所处的温度通常比
最适温度低五到十摄氏度。
这样做并不是有意虐待动物，而是因为在温暖的环境中，动物具有不可控制的攻击性。
降温饲养的不足之处是动物为了保持体温会吃掉比平常更多的食物。
这样会影响动物的生理机能，
从而改变它们对药物的代谢情况，以至于产生令人困惑的实验结果。
斯坦福大学的约瑟夫加纳认为解决这个问题的办法是保持实验室里较低的温度，
但是让小鼠的自然习性—筑建巢穴，而非吃更多的食物—来应对低温。
可是到目前为止，人们还不能确定提供多少筑巢材料才能使小鼠保持良好的状态。
然而，加纳博士和他的同事决心找出答案，
不久前他们将实验结果发表在《公共科学图书馆》杂志上。
加纳博士和他的团队将36只雄鼠与同等数量的雌鼠置于由一条细管道连接的两只笼子里，
并让它们自由活动，这些小鼠来自临床试验中常用的三个种系。
其中一只笼子保持在20°C到35°C之间指定的六个温度中的一个；
另一个则维持在20°C，但其中填入了10克经精心加工过的碎纸屑。
此举是为了观察这些小动物会在较冷笼子里建一个巢穴，还是会通过管道爬至较暖和的笼子
中，甚至还可能不辞辛苦地将这些筑巢材料一点一点地带过去。
研究人员发现这些啮齿动物的喜好随着种系和性别的不同而有轻微的改变。此项结果表明，
并没有单一的一套环境条件能让所有的小鼠感到舒适。
不过通常情况下，在周围没有筑巢材料时，小鼠们会勤劳地将纸屑一点一点地运到更暖和的
笼子里，
但会在较冷笼子里留下至少6克的纸屑。而且许多小鼠会勇于面对寒冷，并在那里筑起自
己的家。
如此情况下，为了更好的进行药物试验，这已算是极小的代价了。