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
医学
Smoking causes wrinkles by upsetting the body’ s mechanism for renewing skin, say scientists in Japan. Dermatologists say the fi
Smoking causes wrinkles by upsetting the body’ s mechanism for renewing skin, say scientists in Japan. Dermatologists say the fi
admin
2013-10-31
91
问题
Smoking causes wrinkles by upsetting the body’ s mechanism for renewing skin, say scientists in Japan. Dermatologists say the finding confirms the long-held view that smoking ages skin prematurely.
Skin stays healthy and young-looking because of a fine balance between two processes that are constantly at work. The first breaks-down old skin while the second makes new skin. The body breaks down the old skin with enzymes called matrix metalloproteinases, or MMPs, They chop up the fibers that form collagen(胶原质)—the connective tissue that makes up around 80 percent of normal skin.
Akimichi Morita and his colleagues at Nagoya City University Medical School suspected that smoking disrupted the body’ s natural process of breaking down old skin and renewing it. To test their idea, they first made a solution of cigarette smoke by pumping smoke through a saline(盐的)solution. Smoke was sucked from cigarettes for two seconds every minute. Tiny drops of this smoke solution were added to dishes of human fibroblasts, the skin cells that produce collagen.
After a day in contact with smoke solution, the researchers tested the skin cells, to see how much collagen-degrading MMP they were making. Morita found that cells exposed to cigarette smoke had produced far more MMP than normal skin cells.
Morita also tested the skin cells to see how much new collagen they were producing. He found that the smoke caused a drop in the production of fresh collagen by up to 40 percent.
He says that this combined effect of degrading collagen more rapidly and producing less new collagen is probably what causes premature skin ageing in smokers, in both cases, the more concentrated the smoke solution the greater the effect on collagen. " This suggests the amount of collagen is important for skin ageing," he says. "It looks like less collagen means more wrinkle formation".
Morita doesn’ t know if this is the whole story of why smokers have more wrinkles. But he plans to confirm his findings by testing skin samples from smokers and non-smokers of various ages to see if the smoking has the same effect on collagen. "So far we’ ve only done this in the lab. " he says. " We don’t know exactly what happens in the body yet that might take some time. "
Other dermatologists are impressed by file work. "This is fascinating," says Lawrence Parish. Director of the Centre for International Dermatology at Thomas Jefferson University Hospital in Philadelphia. This confirms scientifically what we’ve long expected, he says. "Tobacco smoke is injurious to skin. "
As inferred from Morita’ s results, smoking______.
选项
A、could stimulate tile production of fresh collagen
B、is unlikely to promote the production of MMP
C、tends to cause skin to age prematurely
D、may cause collagen to die by 60%
答案
C
解析
文章倒数第三段提到Morita说collagen老化快而产生的又少,所以causes prematureskin ageing in smokers,即吸烟会导致皮肤衰老加快,选项C正确。
转载请注明原文地址:https://kaotiyun.com/show/cTU3777K
本试题收录于:
医学博士外语题库考研分类
0
医学博士外语
考研
相关试题推荐
Twoequallybrilliantscientistsapplyforaprestigiousresearchfellowshipawardedbyatopscientificorganization.Oneiswh
Twoequallybrilliantscientistsapplyforaprestigiousresearchfellowshipawardedbyatopscientificorganization.Oneiswh
PeoplefromaroundtheworldflocktotheUnitedStatesexpectingtofindabetterlife.Buttoscientists’surprise,agrowing
ThecontroversyaboutabortionhasbeengoingonintheUnitedStatesformorethantwentyyears.
Smokingmakesonesixtimesmorelikelytogetoralcancerpartlybecausethesmokeconstantlyassaultsthetissuesthatlineth
Smokingcauseswrinklesbyupsettingthebody’smechanismforrenewingskin,sayscientistsinJapan.Dermatologistssaythefi
WELL—dotheyordon’tthey?Foryears,controversyhasragedoverwhethertheelectromagneticfieldsproducedbypowerlinescou
Whetherthecauseismaternalanti-bodies,heavymetalsorsomethingelse,thereisnoquestionthatthebrainsofyoungchildre
ThequestionnowiswhetherawarinIraq,eventhoughmuchsmaller,mightalsotriggermomentoussideeffects.
随机试题
子宫脱垂病人,宫颈及部分宫体脱出阴道口,应属
A.阳亢化风证B.阴虚风动证C.肝热动风证D.血虚生风证E.肾虚痰浊上扰证
某企业一栋三层办公楼于两年前在某商业银行贷款500万元,在抵押期间该办公楼出租给某公司作办公用房,现因该企业无力偿还债务,银行申请以拍卖变现方式执行债务清偿,委托某房地产评估公司对该办公楼进行拍卖底价评估。作为房地产评估公司,请选择两种主要的房地产估价方法
企业核算交易性金融资产的现金股利时,可能涉及的会计科目有()。
下列不属于诱骗投资者买卖证券、期货合约罪主体的是()。
下列各项中,不需要缴纳耕地占用税的是()。
地方陪同导游人员不同于全程陪同导游人员的职责有()。
维护个人利益是个人行为的唯一动机。因此,维护个人利益是影响个人行为的主要因素。以下哪项如果为真,最能削弱题干的论证?
在下面Excel2003提供的算术运算符中,优先级最高的是______。A.+B./C.%D.**
A、Waiterandcustomer.B、Goodfriends.C、Husbandandwife.D、Colleagues.B场景推理题。题目询问两个对话者是什么关系。对话开头女士没拿定主意吃什么,希望男士提些建议,很多考生以为男士是
最新回复
(
0
)