首页
外语
计算机
考研
公务员
职业资格
财经
工程
司法
医学
专升本
自考
实用职业技能
登录
考研
[A]But as six years stretched to 10, then to 14, the anxiety of health officials gave way to astonishment. Although two of the r
[A]But as six years stretched to 10, then to 14, the anxiety of health officials gave way to astonishment. Although two of the r
admin
2016-11-11
77
问题
[A]But as six years stretched to 10, then to 14, the anxiety of health officials gave way to astonishment. Although two of the recipients have died from other causes, not one of the man’s contaminated blood has come down with AIDS. More telling still, the donor is also healthy. In fact his immune system remains as robust as if he had never tangled with HIV at all. What could explain such unexpected good fortune?
[B]If this speculation proves right, it will mark a milestone in the battle to contain the late-20th century’s most terrible epidemic. For in addition to explaining why this small group of people infected with HIV has not become sick, the discovery of a viral strain that works like a vaccine would have far-reaching implications. "What these results suggest," says Dr. Barney Graham of Tennessee’s Vanderbilt University, "is that HIV is vulnerable and that it is possible to stimulate effective immunity against it. "
[C]The strain of HIV that was discovered in Sydney intrigues scientists because it contains striking abnormalities in a gene that is believed to stimulate viral duplication. In fact, the virus is missing so much of this particular gene-known as nef, for negative factor—that it is hard to imagine how the gene could perform any useful function. And sure enough, while the Sydney virus retains the ability to infect T cells—white blood cells that are critical to the immune system’s ability to ward off infection—it makes so few copies of itself that the most powerful molecular tools can barely detect its presence.
[D]At the very least, the nef gene offers an attractive target for drug developers. If its activity can be blocked, suggests Deacon, researchers might be able to bring the progression of disease under control, even in people who have developed full-blown AIDS. The need for better AIDS-fighting drugs was underscored last week by the actions of a U. S. Food and Drug Administration advisory panel, which recommended speedy approval of two new AIDS drugs. Although FDA commissioner David Kessler was quick to praise the new drugs, neither medication can prevent or cure AIDS once it has taken hold. What scientists really want is a vaccine that can prevent infection altogether. And that’s what makes the Sydney virus so promising-—and so controversial.
[E]A team of Australian scientists has finally solved the mystery. The virus that the donor contracted and then passed on, the team reported last week in the journal Science, contains flaws in its genetic script that appear to have rendered it harmless. "Not only have the recipients and the donor not progressed to disease for 15 years," marvels molecular biologist Nicholas Deacon of Australia’s Macfarlane Burnet Centre for Medical Research, "but the prediction is that they never will. " Deacon speculates that this "impotent" HIV may even be a natural inoculant that protects its carriers against more virulent strains of the virus.
[F]But few scientists are enthusiastic about testing the proposition by injecting HIV—however weakened—into millions of people who have never been infected. After all, they note, HIV is a retrovirus, a class of infectious agents known for their alarming ability to integrate their own genes into the DNA of the cells they infect. Thus once it takes effect, a retrovirus infection is permanent.
[G]About 15 years ago, a well-meaning man donated blood to the Red Cross in Sydney, Australia, not knowing he has been exposed to HIV-1, the virus that causes AIDS. Much later, public health officials learned that some of the people who got transfusions containing his blood had become infected with the same virus: presumably they were almost sure to die.
Order:
选项
答案
A
解析
文章第一段谈到了有位好心的人把自己已感染HIV-1型血液捐给了别人,结果这些接受者们也感染了这个病毒。本段内容应该是接着讨论这些感染者们在被感染了HIV-1型病毒后的情况,所以A项“……这些感染者们没有一个感染艾滋病,并且那位献血者仍然活的好好的……”符合本段题意。
转载请注明原文地址:https://kaotiyun.com/show/bWoZ777K
0
考研英语一
相关试题推荐
For10yearsIhavebeenteachinganimalbehaviorandconservationbiologyattheBoulderCountyJailinColorado.Thecourse—pa
Newspapersarebecomingmorebalancedbusinesses,withahealthiermixofrevenuesfromreadersandadvertisers.Americanpapers
Thedestructionofournaturalresourcesandcontaminationofourfoodsupplycontinuetooccur,largelybecauseoftheextreme
IntheUnitedStates,thefirstdaynursery,wasopenedin1854.Nurserieswereestablishedinvariousareasduringthe【C1】_____
IntheUnitedStates,thefirstdaynursery,wasopenedin1854.Nurserieswereestablishedinvariousareasduringthe【C1】_____
IntheUnitedStates,thefirstdaynursery,wasopenedin1854.Nurserieswereestablishedinvariousareasduringthe【C1】_____
IntheUnitedStates,thefirstdaynursery,wasopenedin1854.Nurserieswereestablishedinvariousareasduringthe【C1】_____
Eatinghealthilycostsabout$1.50moreperpersondaily,accordingtothemostthoroughreviewyetoftheaffordabilityofahe
Thedifferencebetween"writer"and"reporter"or"journalist"isn’tthatthejournalistreports—she【C1】______sources,callspeo
随机试题
甲、乙、丙分别购买了某住宅楼(共3层)的一层、二层、三层,各自办理了房产证。现丙欲出售其住宅,对丙出售的住宅
A.过敏性紫癜B.特发性血小板减少性紫癜C.单纯性紫癜D.继发性血小板减少性紫癜E.血栓性血小板减少性紫癜以下患者均有紫癜,选择出正确诊断:女性,19岁。双膝关节疼痛5天伴双下肢瘀点就诊。体检:双下肢内
在中央银行选用的管制工具中,起到一种“信号导向”作用的管制工具是()。
甲、乙、丙、丁分别出资20万、30万、40万、10万元建造一栋楼房,约定建成后按投资比例使用,但对楼房管理和所有权归属未作约定。对此,下列说法错误的是()。
声音的高低由()决定。
(2013年真题)甲(15周岁)拐骗一名男孩,准备将其出卖,后因小孩哭闹不止,甲对其进行殴打,造成重伤,甲的行为构成
事物内部的肯定方面和否定方面的对立统一运动,从表现形式上看()
设F1(x),F2(x)分别为随机变量X1与X2的分布函数,概率密度分别为f1(x),f2(x)(两个函数均连续),则必为概率密度的是()
人员的记录由编号和出生年、月、日组成,N名人员的数据已在主函数中存入结构体数组std中。函数fun的功能是:找出指定出生年份的人员,将其数据放在形参k所指的数组中,由主函数输出,同时由函数值返网满足指定条件的人数。请在程序的下划线处填入正确的内容
Nowtheincomegapisgettingwiderandwider.Insomeprivatelyownedfirms,【B1】______,orforeign-fundedcompanies,an【B2】___
最新回复
(
0
)