2019年02月22日 09:47:26|来源:国际在线|编辑:搜医乐园
Finance and economics财经商业High-yield bonds高利债券An appetite for junk来点垃圾Companies have taken advantage of investorsgrowing willingness to buy speculative bonds公司很好的利用了投资者日益高涨的购买投机性债券的意愿WHEN cash deposits pay virtually zero, investors have an incentive to take risks in search of higher returns.当存款利率近乎于零,投资者便会冒险寻求更高收益。That has been good news for the high-yield, or junk, bond market, where companies with poor credit ratings turn for finance.而这对于高利债券、或垃圾债券市场来说,无疑是个好消息,那些信用评级差的公司通常通过这种方式融资。Many companies can now borrow at rates that governments would have been pleased to achieve two decades ago.现在,许多公司可以以各国政府二十年前喜闻乐见的利率获得投资。Indeed, so low have borrowing costs fallen that some wags have dubbed the market the asset class formerly known as high-yield.诚然,借贷成本降至如此之低,甚至有人将其戏称为前高利债券。Until the hiatus related to the budget crisis inAmerica, companies were rushing to take advantage of this financing opportunity.直到此次美债违约,各家公司纷纷借助这股东风融资。In the first nine months of the year global high-yield-bond issuance reached 378.2 billion, up by 27% on the same period in 2012, according to Dealogic, a financial-data firm. Sprint,据金融数据公司迪罗基称,今年前九个月发现的高利债券达到了3782亿美元,同比增长27%。an American telecoms company, raised 6.5 billion in two simultaneous bond issues, the largest-ever junk financing.美国电信公司Sprint通过同步发行债券筹集到了65亿美元,这也是迄今为止最大的垃圾融资。Low rates will not last forever, so companies are keen to take advantage of what might be an historic opportunity.低利率不会持续太久,公司自然不会错过这次千载难逢的机会。And investors have been happy to take the extra yields on offer, given the positive returns achieved since .鉴于年后获得正收益,投资者也乐意出资获取额外收益。In America, the modern high-yield-bond market dates back to the 1980s. Until then, high-yield bonds were usually fallen angels—companies which previously had an investment-grade credit rating but had seen their finances suffer.美国现代高利债券起源于上世纪八十年代。在那之前,高利率债券通常都是落难天使—此前已获得投资信用评级的公司都遭遇过财务危机。But Michael Milken and his team at Drexel Burnham Lambert, an investment bank, discovered there was a market for high-yield debt from new issuers, often in connection with companies making takeover bids.但是,德瑞债券的迈克尔米尔肯为高利债券发行者发现了新的市场,而这通常和公司收购行动密不可分。The market is now huge.现在,这一市场前景广阔,A study by Russell, a consultancy, estimated its total size at 1.7 trillion.咨询公司Russell预计其总需求为1.7万亿。Almost half of all the corporate bonds rated by Standard amp; Poors are classed as speculative, a polite term for junk.标普公司发布的信用评级中超过半数公司债券均为投机性债券—垃圾债券的委婉说法。Part of this is down to fashion; companies have been urged to return spare cash to shareholders and to make their balance-sheets more efficient by taking advantage of the tax deductibility of interest payments.其中,部分债券已经流于形式,股东撤回公司闲钱,如此便可利用付息债券避税,从而使得资产负债表更加均衡。Another big boost to the market has been the broadening of its base beyondAmerica.高利债券膨胀的另一大原因是除美国市场之外,世界其他地区需求增加。According to Fraser Lundie, a high-yield-bond manager at Hermes,America comprised 89% of the market in 1998; now it forms just 57%.Europehas gone from 3% of the market to 27%.爱马仕高利债券经理弗雷泽伦迪表示,1998年美国国内发行的高利债券占全世界的89%,现在降至57%,而欧洲则由当初的3%增至27%。The rise of high-yield bonds has been handy for European companies in the wake of the financial crisis, as many banks have been seeking to shrink their balance-sheets, and have been less willing to offer loans.随着金融危机的爆发,高利债券发行量的增长对欧洲公司来说也极为便利,因为都减少贷款,平衡资产负债表。Historically, European companies have been much more dependent on bank finance than their American counterparts.从历史观点上说,相对于美国公司,欧洲公司对的依赖更强。They also used to be warier of seeing their bonds classed as junk.过去,欧洲公司甚至害怕其债券被评为垃圾级。Low rates have been good for the market in another way.从另一个层面来说,低利率对市场有利。They have enabled companies to refinance their debt cheaply, and so pushed back the nettlesome day when their finances will be squeezed by higher borrowing costs.因为这样公司可以以低成本获得再融资,当初借贷成本高不说,还很难获得通过,简直苦不堪言。A few years ago there was a worry that a lot of debt would need to be refinanced in 2012 and 2013; now the refinancing hump will not come until 2017 and 2018.几年前,人们担心过多债务会导致2012年、2013年时需要再融资;现在,在2017年、2018年之前再融资峰值是不会出现的。A long period of cheap finance makes it less likely that issuers will be forced to default in the short term, and the reduced likelihood of default makes it more attractive for investors to hold bonds.长期的低成本融资让债券发行方短期内违约的可能性大大降低,违约可能性的降低又会吸引更多投资者持有债券。In the wake of Lehmans collapse, the sp on junk bonds rose so far that it implied default on a scale not seen since the Great Depression.随着雷曼兄弟的破产,垃圾债券的差额大幅增长,这也就导致了大萧条后前所危机的违约浪潮。But after a brief spike to 13.7% in , the default rate on global high-yield bonds dropped steadily and was just 2.8% in September, according to Moodys, another ratings agency.但是,据评级公司穆迪称,年13.7%的违约高峰很快便平息;今年九月,全球高利率债券违约率仅为2.8%。But not all is sunny in the high-yield world.但是,高利债券市场并非总是风平浪静。Although the market has doubled or tripled in size since 2008, liquidity has diminished.尽管自2008年后高利债券市场规模已经增至原来的两至三倍,债券的流动性却降低了。Regulatory restrictions mean that banks no longer hold as much inventory in the form of bonds; since 2002, there has been a decline of almost three-quarters.监管限制让无法继续像以前那样持有太多债券形式的存货。自2002年来,所持债券已经减少了75%。PIMCO, a huge bond-fund manager, said in a recent report, We see reduced liquidity as an important secular trend. It is an unintended consequence of the deleveraging and re-regulation of banks globally. It will result in higher volatility in times of stress.近期,太平洋投资管理公司发布的一篇报道称,我们认为流动性的降低将会是一个重要的长期趋势,这是全球重新平衡、管理的副作用。In other words, if investors ever lose their current enthusiasm for high-yield bonds, they will find it much harder, and probably costlier, to offload them.换句话说,如果投资者对高利债券的热情降低,他们便会发现想要抛售这些债券将会更加困难、或许还会付出更高代价。Meanwhile, the growing enthusiasm for high-yield bonds is likely to diminish the returns they offer.与此同时,随着人们对高利债券愈发热衷,其回报率也会相应降低。In the past investors typically bought junk bonds at a discount to their face value; they hoped that the profits on bonds that were repaid at maturity would offset the losses on the few issuers that defaulted.过去,投资者都是以折扣价买入垃圾债券,他们希望债券到期的收益能够抵消部分违约发行者带来的损失。Yet in May this year the average price of a high-yield bond reached 6% above face value, according to Mr Lundie.然而,据伦迪数据显示今年五月高利债券的平均价格超过了其面值的6%。Holding a bond until maturity will thus result in a capital loss, although investors may still profit from interest.尽管投资者仍可从利息中获利,但持有高利债券直至到期将会造成一定资本损失。Worse, many bonds—perhaps two-thirds or three-quarters of the market—have a call option attached to them that allows the issuer to repay the debt if it reaches a certain price.更糟糕的是许多债券—可能2/3或3/4的现行债券—都有看涨期权,如果债券达到一定价格,发行方可以偿还债务。That allows issuers to take advantage of growing optimism about their prospects to reissue bonds at lower interest.这也就使得发行方可以利用投资者不断高涨的乐观情绪,以更低的利率发行债券。Such call options skew the risk-reward trade-off.看涨期权让风险报酬交易失去了平衡。If a bond gets close to the callable price, it is unlikely to rise much further: who would bid 110 cents for a bond that can be redeemed at 104?如果某个债券接近可赎回价格,其价格也就不大可能会继续涨了:谁会愿意花110美分购买104美分就可以赎回的债券呢?On the other hand, if the company hits hard times, the bond could fall quite sharply in price. So investors face a limited upside and a big downside.另一方面,如果市场萧条,债券价格便会一落千丈。因此,对投资者来说此事弊大于利。That has tended to push investors towards ever riskier assets, such as CCC-rated bonds—the lowest category excluding those issuers that have aly defaulted.这回让投资者转向风险更大的债券,比如除违约债券以外的最低评级债券,CCC级债券。David Newman of Rogge Global Partners, a fund-management firm, reckons that such bonds are now probably overpriced, given the risks involved.来自资金管理公司Rogge Global Partners的大卫纽曼认为考虑到风险因素,这类债券目前可能定价过高。It is in the nature of the bond markets that, when conditions are good, investors get more relaxed about credit quality.债券市场的特性是当市场环境良好,投资者便会对信用质量更加放心。Some observers think that the risks of high-yield bonds are being systematically underestimated.部分观察人士认为,高利债券的风险被普遍低估。The sps paid by high-yield issuers are low relative to the historical average, although they are more than sufficient to compensate investors given the low level of defaults.尽管,考虑到低违约率,债券发行方更加确信可以让投资者收到回报;但是,同历史平均水平相比,现在高利债券发行方所付的利率更低。If central banks start raising interest rates to deal with a resurgence of inflation, or if the global economy slips back into recession, junk-bond investors may suffer a nasty shock. But for the moment they are enjoying the ride.如果央行为了规避通胀而开始提高利率,或者全球经济再度陷入萧条,垃圾债券投资者或许会损失惨重。但是,现在他们正享。 /201310/261375Business商业报道Codelco v Anglo American智利国家铜业公司对战英美资源集团Ore war矿石之战A mineral battle in business-friendly Chile商业环境友好的智利爆发矿产之争LEADERS of countries at war have long warned voters not to throw them out before the shooting stops.战争期间的国家领导人早就提醒过选民,在击停止前不要把他们甩在一边。Although Chile has been at peace since it restored democracy in 1990, its state copper company, Codelco, is embroiled in a fierce legal fight with Anglo American, a global mining conglomerate, over the ownership of rich metal deposits.尽管智利在1990年恢复民主后一直处于和平状态,其国家铜业公司Codelco还是为了与英美资源集团争夺金属富矿的所有权而被卷入到的激烈法律争端中。And it will now have to wage that battle without its boss, Diego Hernandez, who quit his job on May 24th.现在Codelco不得不在没有主帅的情况下进行这场斗争—其执行总裁埃尔南德斯于5月24日辞职。Chiles mining industry has boomed under a hybrid structure, in which Codelco, the worlds biggest copper firm, competes with private rivals.作为世界上最大的铜业公司,Codelco与私营企业不断竞争—智利的采矿工业 在这种混合结构下繁荣起来。The company hired Mr Hernandez, who had previously worked at BHP Billiton, another global miner, mainly to oversee expansion.Codelco雇佣曾供职于必和必拓的Mr Hernandez,主要是为了让他负责公司的扩张战略。Mr Hernandez soon found a tempting acquisition target in Anglo Americans Sur project, consisting of two mines, a smelter, and two recently discovered deposits in the Andes, which are thought to hold a whopping 2.1 billion tonnes of ore.Mr Hernandez很快就发现了一个诱人的收购目标——英美资源集团的苏尔项目,该项目包括两处矿山、一个冶金厂和两处最近在安第斯山发现的两处矿床。In 1978 Codelco acquired an option to buy up to 49% of Sur during a one-month window every three years.1978年Codelco就签订了收购苏尔49%股权的期权的合同,每三年开放一次窗口。In January the company exercised it. Its contract contains a formula for calculating the price, which is based in part on Surs profitability in the five years before purchase.今年一月Codelco宣布行使期权。这份合同包含一个公式,能够根据苏尔在收购前五年的盈利能力等因素计算出其价格。Codelco says this equation values the project at .5 billion.Codelco称根据这个公式该项目价值135亿美元。It secured a .75 billion loan from Mitsui, a Japanese firm, to pay for its share.Codelco已经从日本三井物产获得67.5亿美元的担保贷款来购买这些股权。However, the formula takes no account of the new finds at Sur or Anglo Americans investment in it.但是,这个公式没有考虑到苏尔公司新发现的矿产或者是Anglo American对苏尔的投资。To fend off Codelco, Anglo agreed with Mitsubishi, another Japanese trading house, to sell a 24.5% stake for .4 billion.为了抵制Codelco的收购,Anglo同意向日本三菱公司以54亿美元的价格出售苏尔集团24.5%的股份。Anglo said Codelco would have to settle for a smaller slice after the Mitsubishi deal closes.Anglo表示,在与三菱公司的交易完成后,Codelco 只能收购在苏尔集团的剩余的部分股份 。Mr Hernandez accused Anglo American of breaching its contract.Mr Hernandez起诉Anglo American违反合约,The two sides went to court.双方对簿公堂。Then on May 22nd they suspended proceedings and agreed to talk.5月22日,双方又推迟诉讼,打算和谈,They gave themselves 30 days to reach a deal.原本计划在30天内达成一致意见,But two days later Mr Hernandez abruptly quit.但2天后,Mr Hernandez突然辞职。He said his departure had nothing to do with the Anglo spat,Mr Hernandez表示他的离职与Anglo争端无关,but rather with the companys board, which he accused of micromanagement.而是对公司董事会事无巨细的微观管理方式不满。In 2010 Chile overhauled Codelcos administrative structure, transforming the board from a mere rubber stamp into a real check on management.2010年智利政府对Codelco的行政结构进行了整改,董事会获得了对公司管理层的监管权力,不再像以前那样只是个橡皮图章。Industry observers say the new organisation has led to better decision-making.业内观察家认为新的组织架构可以更好地作出决策。But Mr Hernandez apparently grew tired of having to explain himself at every turn in interminable meetings.但是Mr Hernandez显然已经厌倦了在没完没了的会议上一遍又一遍的解释自己的做法。His successor is Thomas Keller, the companys chief financial officer, formerly of Royal Dutch Shell.Mr Hernandez的继任者是公司首席财务官托马斯.凯勒,曾在荷兰皇家壳牌公司工作过。Industry observers say Mr Keller is a more open boss than Mr Hernandez.业内观察家认为相比Mr Hernandez ,Mr Keller是一个思想更为开放的老板。Although Mr Keller will probably pursue a similar corporate strategy, Anglo American may try to take advantage of the turmoil to adopt an even tougher stance in negotiations.尽管Mr Keller很可能继续推行与Mr Hernandez相似的公司战略,Anglo American可能会利用这段混乱期,以在谈判中采取更强硬的立场。How the government-appointed board will advise the new boss remains to be seen.政府委任的董事会将对这位新经理提出怎样的建议,目前还不得而知。Chile would love to get its hands on Sur, and will face domestic pressure not to buckle:智利政府十分希望能够拥有苏尔项目,同时也将面对难以克的国内压力:politicians and union leaders have accused Anglo American of trying to rob the country of its God-given copper, and public opinion frowns on foreign control of mines.政客和工会领导人来控诉Anglo American试图强占本属该国的铜矿资源,公共舆论也对外国控制国内矿山表示不满。But Chile also wants to protect its relationship with Britain and its reputation as one of Latin Americas safest places to invest.但与此同时,智利政府也希望保持与英国的关系,并维护好自己作为拉丁美洲最安全的投资国的名声。Mr Keller may guide Codelco to a settlement, but he might soon find himself as frustrated as Mr Hernandez was with a process that is as much about politics as it is about business.Mr Keller可能会引导Codelco合理解决现有问题,但今后他除了经营公司,还要应付许多政治活动—这可能很快会让他变得和前任Mr Hernandez一样沮丧。 点击此处下载本期经济学人讲解PDF与音频字幕 /201307/246231

Science and technology科学技术Climate change气候变化Good news at last?终于来了好消息?The climate may not be as sensitive to carbon dioxide as previously believed气候对二氧化碳的敏感性可能低于先前的预期CLIMATE science is famously complicated,气候科学的复杂程度众所周知,but one useful number to keep in mind is climate sensitivity.但把一个指标记在脑中非常好用,那就是气候敏感性。This measures the amount of warming that can eventually be expected to follow a doubling in the atmospheric concentration of carbon dioxide.该指标表示预计大气中二氧化碳浓度翻倍所能引致的升温量。The Intergovernmental Panel on Climate Change, in its most recent summary of the science behind its predictions, published in 2007, estimated that,政府间气候变化专门委员会在其最近一次关于其预测背后的科学性的概要中估计,in present conditions, a doubling of CO2 would cause warming of about 3C, with uncertainty of about a degree and a half in either direction.在如今的情况下,二氧化碳浓度翻倍将造成3C左右的升温,上下误差在1.5度左右。But it also says there is a small probability that the true number is much higher. Some recent studies have suggested that it could be as high as 10C.但该概要也声称,真实数据有少许可能还要高得多。一些近期的研究也猜测气温上升可能达到10C之高。If that were true, disaster beckons.如果这种猜测属实,灾难说来就来了。But a paper published in this weeks Science, by Andreas Schmittner of Oregon State University, suggests it is not.但美国俄勒冈州立大学的安德烈亚斯-施密特纳在本周《科学》杂志上刊登的一篇报告认为,情况并非如此。In Dr Schmittners analysis, the climate is less sensitive to carbon dioxide than was feared.在施密特纳士的分析中,气候并不像先前人们所担忧的那样对二氧化碳那么敏感。Existing studies of climate sensitivity mostly rely on data gathered from weather stations, which go back to roughly 1850.现有的关于气候敏感性的研究主要基于气象站收集的数据,可以追溯到公元1850年左右。Dr Schmittner takes a different approach. His data come from the peak of the most recent ice age, between 19,000 and 23,000 years ago.施密特纳士采用了另外一种方法。他的数据来源于最近一次冰河时期的顶峰。His group is not the first to use such data to probe the climates sensitivity to carbon dioxide. But their paper is the most thorough.他的团队不是第一个使用这些数据来探测气候对二氧化碳的敏感性的团队。但他们的报告是最全面彻底的。Previous attempts had considered only small regions of the globe.过去的研究只考虑了全球的小部分地区。He has compiled enough information to make a credible stab at recreating the climate of the entire planet.而他汇编了足够的信息,可以确凿地尝试一下重建整个地球的气候模型。The result offers that rarest of things in climate science—a bit of good news.研究的结果给出了气候科学中最为罕见之物—一丁点好消息。The groups most likely figure for climate sensitivity is 2.3C, which is more than half a degree lower than the consensus figure,该研究组给出最有可能的气候敏感性数字是2.3C,比公认的数据低了半度多,with a 66% probability that it lies between 1.7 and 2.6C.并且该数字有66%的几率位于1.7C到2.6C之间。More importantly, these results suggest an upper limit for climate sensitivity of around 3.2C.更重要的是,研究结果指出,气候敏感性的上限在3.2C左右。Before you take the SUV out for a celebratory spin, though, it is worth bearing in mind that this is only one study,但是在你把SUV开出去兜风以作庆祝之前,要记住这只是一项研究而已,and, like all such, it has its flaws.并且—就如同所有这类研究一样—研究自身也有缺陷。The computer model used is of only middling sophistication, Dr Schmittner admits.施密特纳士承认,该研究采用的电脑模型的复杂程度一般。That may be one reason for the narrow range of his teams results.这可能也是他的团队实验结果范围较窄的一个原因。And although the studys geographical coverage is the most comprehensive so far for work of this type, there are still blank areas,而且,尽管这项研究的地理覆盖范围是迄今为止同类中最大的,它仍有空白区域notably in Australia, Central Asia, South America and the northern Pacific Ocean.尤其指澳洲,中亚,南美和北太平洋地区。Moreover, some sceptics complain about the way ancient data of this type were used to construct a different but related piece of climate science:此外,一些怀疑论者对这些远古数据被用来构建一个不同的但是相关的气候学分:the so-called hockey-stick model, which suggests that temperatures have risen suddenly since the beginning of the industrial revolution.所谓的曲棍球棒模型认为气温自从工业革命以后就突然上升满腹牢骚。It will be interesting to see if such sceptics are willing to be equally sceptical about ancient data when they support their point of view.看看当远古数据持这些怀疑论者的观点时,这些人是否还愿意以同等的怀疑态度对待,这一定会非常有趣。 /201308/250601

Science and technology科学技术Embryonic stem cells胚胎干细胞Looking up进展中的干细胞研究Stem-cell research is now bearing fruit 干细胞研究开始结出硕果FOURTEEN years ago James Thomson of the University of Wisconsin isolated stem cells from human embryos.十四年前,当威斯康辛大学的 James Thomson从人类胚胎细胞中分离出干细胞时,It was an exciting moment.人们无不为之欢呼雀跃。The ability of such cells to morph into any other sort of cell suggested that worn-out or damaged tissues might be repaired,这种细胞可分裂、转变成为各种器官、组织,因此或将被用于修复、and diseases thus treated a technique that has come to be known as regenerative medicine.治疗损伤、病变的组织,这一技术被称为再生医疗。Since then progress has been erratic and controversial.但随后这一领域的发展呈现了不稳定性、胚胎细胞的来源问题也引发了社会争议。But, as two new papers prove, progress there has indeed been.但是这两篇新论文的发表,明了干细胞研究取得了一定的进展。This weeks Lancet published results from a clinical trial that used embryonic stem cells in people.本周《柳叶刀》刊出了胚胎干细胞应用于人体的临床实验的结果。It follows much disappointment.人们对这样的消息常常都是失望:In November, for example, a company in California cancelled what had been the first trial of human embryonic stem cells, in those with spinal injuries.例如,去年11月,一家位于加州的公司取消了原定的首例人胚胎干细胞在脊髓损伤者身上的试验。Steven Schwartz of the University of California, Los Angeles, however, claims some success in treating a different problem: blindness.但是洛杉矶加州大学的Steven Schwartz说他在干细胞治疗其它疾病:如失明,就取得了一些成绩。His research, sponsored by Advanced Cell Technology, a company based in Massachusetts, involved two patients.他的研究是在先进细胞技术院的赞助下进行的,这家公司位于马萨诸塞州,两名病患参与了试验,One has age-related macular degeneration, the main cause of blindness in rich countries.一位是老年性黄斑变性病患者,这是发达国家盲人病患常见的致盲原因。The other suffers from Stargardts macular dystrophy, its main cause in children.另一位是隐性黄斑营养不良症患者,这是儿童致盲的主要原因。Dr Schwartz and his team coaxed embryonic stem cells to become retinal pigment epithelium tissue which supports the rod and cone cells that actually respond to light他的团队诱导胚胎干细胞成为视网膜色素上皮组织细胞-其中的杆细胞及锥晶细胞对光线敏感。then injected 50,000 of them into one eye of each patient,然后给每个参试病患的眼睛内注射50,000单位的此种细胞,with the hope that they would bolster the natural supply of these cells.希望这些细胞能在体内像原有细胞一样自然生长。The result was a qualified success.结果相当成功。First and foremost, neither patient had an adverse reaction to the transplant always a risk when foreign tissue is put into someones body.首先,也是最重要的是,两位病患都没有对新移植的细胞产生排斥-这是移植异体组织常常要面临的风险。Second, though neither had vision restored to any huge degree, each was able, four months after the transplant,其次,虽然两名患者的视力没有很大程度的恢复,但移植4个月后,to distinguish more letters of the alphabet than they could beforehand.与患病前相比,他们都能识别出更多视力表上的字母了。Whether Dr Schwartzs technique will prove truly useful remains to be seen. Experimental treatments fail far more often than they succeed.但现在就确定的说Dr Schwartz的技术很实用还为时尚早,失败的试验远比成功的案例更多。But the second paper, published in Nature by Lawrence Goldstein of the University of California, San Diego, and his colleagues,但由圣迭戈加州大学的 Lawrence Goldstein及其同事发表在《自然》杂志的这篇论文,shows how stem cells can be of use even if they do not lead directly to treatment.也是我想说的第二篇论文,就能看出干细胞尽管还不能直接用于治疗,但已经相当“好使”了。Since 2006 researchers have been able to reprogram adult cells into an embryonic state, using proteins called transcription factors.自从2006年以来,研究人员已经能用一种称为转录因子的蛋白质分子将体细胞诱导成为类似胚胎细胞的干细胞,Though these reprogrammed cells, known as induced pluripotent stem cells, might one day be used for treatment,尽管这种诱导多潜能干细胞迟早会有一天能在再生医疗领域大展拳脚,their immediate value is that they are also an excellent way to understand illness.但眼下,它们的价值则体现在对疾病的研究上,这是个很好的方法。Using them, it is possible to make pure cultures of types of cells that have gone wrong in a body.利用它们就能离体培养出与体内患病组织相同类型的细胞来。Crucially, the cultured cells are genetically identical to the diseased ones in the patient.关键是,这些培养出的细胞与患者的染病细胞在基因组成上是相同的。Dr Goldstein is therefore using iPS cells to try to understand Alzheimers disease.因此,Dr Goldstein将用iPS来揭开阿尔茨海默症的病因。The brains of those with advanced Alzheimers are characterised by deposits,重症阿尔茨海默病患者的大脑内明显特征是,有一种称为淀粉样蛋白碎片的积淀物,known as plaques, of a protein-fragment called beta-amyloid, and by tangles of a second protein, called tau.也是我们所称的斑块,与另一种蛋白的结团物。But how these plaques and tangles are related remains unclear.但这些斑块和结团是何种关系还不明确。To learn more, Dr Goldstein took tissue from six people:为了深入研究, Dr Goldstein从6位病患身上取了组织:two with familial Alzheimers, a rare form caused by a known genetic mutation;2位是家族阿尔茨海默病患者-因较罕见的基因突变所引发的;two with sporadic Alzheimers, whose direct cause is unknown; and two unaffected individuals who acted as controls.2位是散发性阿尔茨海默病患者-致病原因不详;2位是行动可控的未患病者。He reprogrammed the cells collected into iPS cells, then nudged them to become nerve cells.先将收集的体细胞诱导成iPS,再用这些iPS细胞转化神经细胞。In three of the four Alzheimers patients these lab-made nerve cells did,4位阿尔茨海默病患者中,3位的实验获得神经细胞中,表现出高水平的淀粉样蛋白和蛋白,indeed, show higher levels of beta-amyloid and tau and also of another characteristic of the disease, an enzyme called active GSK3-beta.并且,与此疾病相关的另一特征:一种称为GSK3活性酶的水平也较高。Since he now had the cells in culture, Dr Goldstein could investigate the relationship between the three.于是,他将这三种神经细胞植入培养皿中培养,以发现三者之间的关系。To do so he treated the cultured cells with drugs.之后,他就能用药物来处理培养出的细胞。He found that a drug which attacked beta-amyloid directly did not lead to lower levels of tau or active GSK3-beta;他发现用药物直接处理淀粉样蛋白并不能致使Tau蛋白和GSK3活性酶的水平降低;but a drug which attacked one of beta-amyloids precursor molecules did have that effect.但如果用药物处理淀粉样蛋白的前体分子,效果就会很好。That is useful information, for it suggests where a pharmacological assault on the disease might best be directed.这是很有价值的信息,能判断在哪里用药才能直达病灶。In the short term, at least, iPS-based studies of this sort are likely to yield more scientific value than clinical experiments of the type conducted by Dr Schwartz,在短期内,此类基于iPS的研究在科学价值方面的意义远大于Dr Schwartz进行的临床实验结果,even though they are not treatments in themselves.因为他们的研究本身还不能用于治疗病患。That will, though, require many more pluripotent cells.不过,对多潜能干细胞的需求会与日俱增,And at least one firm is selling a way to make billions of iPS cells for just that purpose.至少有一家公司会源源不断的提供数十亿的iPS细胞用于此类研究,Its founder, appropriately, is Dr Thomson.它的创始人正是Thomson. /201403/279987

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