2017 考博英语 阅读题源经济学人文章每日精析（三十三）

考博英语阅读大部分博士研究生招生院校都使用《经济学人》杂志文章作为题源，考博信息网|http://www.kaoboinfo.com教育考博频道为考博生们将其中的文章进行深度分析，希望能提高大家的考博英语阅读水平，读懂长难句。

导读

生物钟是生物体内的一种无形的“时钟”，实际上是生物体生命活动的内在节律性，它是由生物体内的时间结构序所决定。生物钟紊乱，松果体素极度减少和丧失正常节律，将牵动体内许多生理功能的紊乱，出现睡眠障碍、内分泌失调、免疫功能下降，损害健康甚至发生疾病

Why disrupted body clocks trigger liver cancer

为何生物钟混乱能诱发肝癌

Shift work and jet lag can induce hepatic tumours. Here’s how

告诉你为什么倒班与时差能诱发肝肿瘤

Dec 3rd 2016 | From the print edition

2016年12月3日|摘自印刷版

DRINKING too much and eating too much are both good ways of getting liver cancer. But there is a third. The disrupted circadian rhythms caused by working shifts or crossing time zones also seem to induce the disease. Precisely how and why meddling with day and night cycles has such a dire effect on the liver remains an enigma, but a study just published in Cancer Cell by Loning Fu and David Moore at the Baylor College of Medicine, in Texas, sheds some light on the matter.

喝太多和吃太多，都很容易患上肝癌。但是这有第三个诱因。那就是倒班或者跨时区而引起的生物钟混乱。具体为何昼夜混乱对肝脏有如此严重的影响，还仍然是个谜，但是德克萨斯州贝勒医学院的Loning Fu和David Moore刚刚在《癌细胞》杂志发表了一项研究给这个问题提供了一些解释。

circadian rhythms ：生物周期节律

Among the liver’s many jobs is making bile, a substance secreted into the intestine to break down the fats and oils in food. One of bile’s main components is bile acid, a derivative of cholesterol. Dr Fu and Dr Moore knew from their previous research that disrupting the circadian rhythms of mice causes the rodents’ livers to overproduce this substance. They also knew that liver cancer commonly appears in mice engineered to lack certain genes required for the management of day-night cycles. This led them to suspect a link between liver cancer and too much bile acid. To take a closer look, they set up an experiment.

肝脏做的大部分工作就是分泌胆汁(一种分泌到肠道中用来分解食物中的脂肪和油的物质)。胆汁的主要成分之一是胆汁酸，它是胆固醇的衍生物。Fu博士和Moore博士从先前的研究中得知，破坏小鼠的昼夜节律会导致啮齿类动物的肝脏过度分泌此物质。他们还了解到肝癌通常出现在缺乏某些掌管昼夜循环基因的小鼠体内。这让他们怀疑肝癌与胆汁酸过多有关。为了进一步了解，他们做了一个实验。

component n.成分

derivative n.衍生物

Working with a team of colleagues, the two researchers studied mice that had had their day-night cycles disrupted. A group of 80 of the animals which had previously lived on a cycle of 12 hours in light and 12 hours in darkness had the lights kept on, on one occasion, for 20 hours, instead. Three days later they were again subjected to four hours of darkness rather than 12. This alternation, at three-day intervals, was then kept up for 30 weeks. A group of 110 mice, meanwhile, were maintained on a constant 12-hour cycle as a control.

两位研究者与一组同事一起工作，研究那些昼夜循环紊乱的老鼠。把一组80只原本昼夜间隔是12小时的老鼠，放置在灯光下20个小时。三天后再这样做。然后三天一次保持30周。 同时将一组110只小鼠的对照组的昼夜间隔时间保持在恒定的12小时。

After 12 weeks, and again after 30 weeks, the team killed some of the rodents in order to look at their livers. They found that the livers of animals on the disrupted schedule had accumulated fat and showed evidence of damage. In particular, they overproduced bile acid. Eventually, after 90 weeks, they killed and examined the remaining animals. Just under 9% of the cycle-disrupted mice, they discovered, had developed liver cancer. None of the control mice had done so.

团队分别在第12周和30周时，对部分啮齿动物进行了解剖，以便研究肝脏的变化。他们发现生物钟紊乱的动物的肝脏中有了脂肪化和受损的迹象。特别是它们的肝脏分泌了过多的胆汁酸。最终90周后团队解剖了余下的实验小鼠，并发现生物钟循环紊乱的小鼠中患有肝癌的比例差一点就到9%。而对照组的小鼠无一罹患肝癌。

In need of regeneration

再生需求

The probable cause of these differences emerged when the researchers ran two similar follow-up experiments using genetically engineered mice. Some of the mice lacked the gene needed to make the constitutive androstane receptor (CAR), a molecule involved in clearing away bile acid. This gene is activated when levels of bile acid get too high. CAR molecules help liver tissue to regenerate, since excess acid damages tissue, inhibiting regeneration. However, the cellular proliferation associated with regeneration is the sort of thing that can sometimes get out of hand and lead to cancer.

研究人员用经过基因改良的小鼠进行了两个相似的后续实验，上述实验差异的原因也在后续实验中出现了。一些小鼠缺乏制造雄烷受体(CAR)的基因(一种清除胆汁酸的分子)。此基因在胆汁酸水平过高时会被激活。CAR分子有助于肝组织再生，而过量的酸损伤组织，抑制再生。然而与肝脏再生相关的细胞增殖，有时会失控导致癌症。

regeneration ：再生，重建

proliferation ：增殖

Other mice Dr Fu and Dr Moore looked at lacked a different gene, for a receptor molecule called FXR. This keeps bile-acid production under control in the first place.

Fu博士和Moore博士还研究了其他缺乏另一种的基因(FXR受体分子)的小鼠。该受体是控制胆汁酸量的第一道关口。

In their experiment the researchers found that in mice lacking the gene for CAR, neither those with disrupted day-night cycles nor those used as controls developed liver cancer. In contrast, even if their day-night cycles were uninterrupted almost 30% of mice lacking FXR developed liver cancer. Among those with interrupted cycles the figure was above 60%. On the basis of these results Dr Fu and Dr Moore suggest that developing either a drug that blocks the activity of CAR, to stop cell proliferation, or one that activates FXR, to decrease bile-acid production, could save shift workers and frequent flyers from the threat of liver cancer.

(期待您的翻译，明天会有针对这句话的读者试译详解哟~)相反的，即使昼夜周期正常，大约30%缺乏FXR受体的小鼠也会患上肝癌。而那些昼夜紊乱的小鼠患肝癌的比例超过了60%。基于实验结果，Fu博士和Moore博士认为，开发阻断CAR的活性来阻止细胞增殖或是激活FXR受体减少胆汁酸产生的药物。两者都可以降低倒班和常坐飞机人群罹患肝癌的几率。