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? ?阅读下面这篇短文，短文后有2项测试任务：(1)第23～26题要求从所给的6个选项中为第2～5段每段选择1个正确的小标题；(2)第27～30题要求从所给的6个选项中选择4个正确选项，分别完成每...
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? ?阅读下面这篇短文短文后有2项测试任务1第23～26题要求从所给的6个选项中为第1～4段每段选
? ?阅读下面这篇短文短文后有2项测试任务1第23～26题要求从所给的6个选项中为规定段每段选择1
? ?阅读下面这篇短文短文后有2项测试任务1第23～26题要求从所给的6个选项中为第1～4段每段选
? ?阅读下面这篇短文短文后有2项测试任务1第23～26题要求从所给的6个选项中为第1～4段每段选
? ?阅读下面这篇短文短文后有2项测试任务1第23～26题要求从所给的6个选项中为第2～5段每段选
? ?阅读下面这篇短文短文后有2项测试任务1第23～26题要求从所给的6个选项中为第2～5段每段选
? ?阅读下面这篇短文短文后有2项测试任务1第23～26题要求从所给的6个选项中为第2～5段每段选
? ?阅读下面这篇短文短文后有2项测试任务1第23～26题要求从所给的6个选项中为第1～4段每段选
? ?阅读下面这篇短文短文后有2项测试任务1第23～26题要求从所给的6个选项中为第1～4段每段选
? ?阅读下面这篇短文短文后有2项测试任务1第23～26题要求从所给的6个选项中为第1～4段每段选
? ?阅读下面这篇短文短文后有2项测试任务1第23～26题要求从所给的6个选项中为第2～5段每段选
? ?阅读下面这篇短文短文后有2项测试任务1第23～26题要求从所给的6个选项中为第1～4段每段选
? ?阅读下面这篇短文短文后有2项测试任务1第23～26题要求从所给的6个选项中为第2～5段每段选
? ?阅读下面这篇短文短文后有2项测试任务1第23～26题要求从所给的6个选项中为规定段每段选择1
? ?阅读下面这篇短文短文后有2项测试任务1第23～26题要求从所给的6个选项中为第2—5段每段选
? ?阅读下面这篇短文短文后有2项测试任务1第23～26题要求从所给的6个选项中为第2～5段每段选
? ?阅读下面这篇短文短文后有2项测试任务1第23～26题要求从所给的6个选项中为第1～4段每段选
? ?阅读下面这篇短文短文后有2项测试任务1第23～26题要求从所给的6个选项中为第2～5段每段选
? ?阅读下面这篇短文短文后有2项测试任务1第23～26题要求从所给的6个选项中为第1～4段每段选
? ?阅读下面这篇短文短文后有2项测试任务1第23～26题要求从所给的6个选项中为第2～5段每段选
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NaturalMedicines Sinceearliestdayshumanshaveusedsomekindsofmedicines.Weknowthisbecausehumanshavesurvived.Ancienttreatmentsforinjuryanddiseaseweresuccessfulenoughtokeephumansfromdyingoutcompletely. Theyweresuccessfullongbeforethetimeofmodernmedicine.Beforethetimeofdoctorswithwhitecoatsandshiny发亮的instruments.Beforethetimeofbighospitalswithstrangeandwonderfulequipment. Manypartsoftheworldstilldonothaveuniversity-educateddoctors.Nordotheyhaveexpensivehospitals.Yetinjuriesaretreated.Anddiseasesareoftencured.How?Byancientmethods.Bymedicinesthatmightseemmysteriousevenmagical有魔力的.Traditionalmedicinesareneithermysteriousnormagicalhowever. Throughthecenturiestribal部落的medicinemenexperimentedwithplants.Theyfoundmanyusefulchemicalsintheplants.Andscientistsbelievemanyofthesetraditionalmedicinesmayprovidethecureforsomeoftoday’’smostseriousdiseases. Expertssayalmost80%ofthepeopleintheworlduseplantsforhealthcare.Thesenaturalmedicinesareusednotjustbecausepeoplehavenootherformoftreatment.Theyareusedbecausepeopletrustthem.Indevelopedareasfewpeoplethinkaboutthesourceofthemedicinestheybuyinastore.Yetmanywidely-usedmedicinesarefromancientsourcesespeciallyplants.Someexpertssaymorethan25%ofmodernmedicinescomeinonewayoranotherfromnature. Scientistshavelongknownthatnatureisreallyachemicalfactory.Alllivingthingscontainchemicalsthathelpthemsurvive.Soscientists’interestintraditionalmedicineisnotnew.Butithasbecomeanurgentconcern.Thisisbecausetheearth’’ssupplyofnaturalmedicinesmaybedroppingrapidly. Whatdothemajorityofthepeopleintheworlduseforhealthcare?
Istheclockinthetoweraccurate?
NewTechniquePromisesEarlierCancerDetection AnewtechniquecouldrevolutionizetheearlydetectionofcancergivingsufferersagreaterchanceofbeatingthediseaseAmericanscientistssaid.ResearchersattheMassachusettsInstituteofTechnologyhavedevisedanovelmethodof【51】changesinthenucleusofcellsintheearlieststagesofthedisease.Morethan85percentofallcancersoriginateintheepithelium上皮thatlinestheinternalsurfacesoforgans【52】thebody.Althoughthesearetreatable【53】theyarediagnosedinoneofthepreventablestagesearlybodydamagesarealmost【54】todetectsaidscientistFeld.Wepresentanewoptical-probe光学探子techniquebasedonlight-scatteringspectroscopy分光镜检查thatisable【55】detectprecancerousandearlycancerouscellsincell-richepitheliaheaddedinastatement. Thenewtechniquereliesonthefact【56】cellnucleichangeintheearlystagesofcancerandthedifferencesscatterlightinacharacteristicway.Untilnowthechangeswereonlydetectable【57】abiopsy活检wastakenthescientistssaid.Thenewtechnique【58】inthesciencejournalNaturecanbeusedinconjunctionwitharoutinecancerscreeningandsurveillancetechniquewhichusesanendoscope内窥镜—aflexibleopticalprobe【59】withcameraswhichisinsertedintoacavityinthebody—tocheck【60】cancers. Thescientistssaidthey【61】theirnewtechniqueinfourdifferentorgansduringroutineendoscopiccancerscreening.Thetipoftheopticalprobewasbroughtintocontactwiththetissuetobetestedandthescatteringoflightwasrecordedwithouttheneedforanytissuetobe【62】thescientistssaid.Ourresultsshowthatlight-scatteringspectroscopyhasthepotentialtodetectpre-cancerousbodydamagesandpreinvasivecancersthroughoutthebody.Thistechniqueshould【63】improvetheefficiencyofcancerscreeningandsurveillancethescientistssaid.Cancerisoneofthebiggest【64】inindustrializedcountries.【65】tofiguresfromtheWorldHealthOrganization10millionpeoplewerediagnosedwiththediseaseworldwidein1997andsixmilliondied.
OnAntibodies Substancesforeigntothebodysuchasdisease-causingbacteriaandvirusesandotherinfectiousagentsarerecognizedbythebodysimmunesystemasinvaders.Ournaturaldefensesagainsttheseinfectiousagentsareantibodiesproteinsthatseekouttheantigens抗原andhelpdestroythem. Antibodieshavetwoveryusefulcharacteristics.Firsttheyareextremelyspecific;thatiseachantibodybindstoandattacksoneparticularantigen.Secondsomeantibodiesonceactivatedbytheoccurrenceofadiseasecontinuetoconferresistanceagainstthatdisease.Classicexamplearetheantibodiestothechildhooddiseasesofchickenpox水痘andmeasles. Thesecondcharacteristicofantibodiesmakesitpossibletodevelopvaccines.Avaccine痘苗isapreparationofkilledorweakenedbacteriaorvirusesthatwhenintroducedintothebodystimulatestheproductionofantibodiesagainsttheantigensitcontains. Itisthefirsttraitofantibodiestheirspecificitythatmakesmonoclonalantibodytechnologysovaluable.Notonlycanantibodiesbeusedtherapeutically在治疗上toprotectagainstdisease;theycanalsohelpto.diagnoseawidevarietyofillnessesandcandetectthepresenceofdrugsviralandbacterialproductsandotherunusualorabnormalsubstancesintheblood. Givensuchadiversityofusesforthesediseased-fightingsubstancestheirproductioninpurequantitieshaslongbeenthefocusofscientificinvestigation.Theconventionalmethodwastoinjectalaboratoryanimalwithanantigenandthenafterantibodieshadbeenformedcollectthoseantibodiesfromthebloodserum血清Antibodycontainingbloodserumiscalledantiserum抗血清.Therearetwoproblemswiththismethod:Ityieldsantiserumthatcontainsundesiredsubstancesanditprovidesaverysmallamountofusableantibody. Monoclonalantibodytechnologyallowsustoproducelargeamountsofpureantibodies.inthefollowingway:wecanobtaincellsthatproduceantibodiesnaturally;wealsohaveavailableaclassofcellsthatcangrowcontinuallyincellculture培养.Ifweformahybrid混血儿thatcombinesthecharacteristicofimmortality永生withtheabilitytoproducethedesiredsubstancewewouldhaveineffectafactorytoproduceantibodiesthatworkaroundtheclock. Inmonoclonalantibodytechnologytumorcellsthatcanreplicate重复endlesslyarefusedwithmammaliancellsthatproduceanantibody.Theresultofthiscellfusionisahybridoma杂交瘤whichwillcontinuallyproduceantibodies.Theseantibodiesarecalledmonoclonalbecausetheycomefromonlyonetypeofcellthehybridomacell;antibodiesproducedbyconventionalmethodsontheotherhandarederivedfrompreparationscontainingmanykindsofcellsandhencearecalledpolyclonal.Anexampleofhowmonoclonalantibodiesarederivedisdescribedbelow. Amyelomaisatumorofthebonemarrow骨髓thatcanbeadaptedtogrowpermanendyincellculture.Whenmyelomacellswerefusedwithantibody-producingmammalianspleencellsitwasfoundthattheresultinghybridcellsorhybridomasproducedlargeamountsofmonoclonal骨髓瘤antibody.Thisproductofcellfusioncombinedthedesiredqualitiesofthetwodifferenttypesofcells:theabilitytogrowcontinuallyandtheabilitytoproducelargeamountsofpureantibody. Becauseselectedhybridcellsproduceonlyonespecificantibodytheyaremorepurethanthepolyclonalantibodiesproducedbyconventionaltechniques.Theyarepotentiallymoreeffectivethanconventionaldrugsinfightingdiseasesincedrugsattacknotonlytheforeignsubstancebutthebody’sowncellsaswellsometimesproducingundesirablesideeffectssuchasnausea恶心andallergicreactions.Monoclonalantibodiesattackthetargetmoleculeandonlythetargetmoleculewithnoorgreatlydiminishedsideeffects. Whichofthefollowingstatementsisfalse?
TheFunctionofTomatoes Howdowelovetomatoes?Let’’scounttheways:welovetheminpastaonpizzainjuiceinsaladandsoupslicedonsandwichesstuffedwithtunaevendriedandbakedinbagelsbutmostofallwelovethemrightoffvine—riperedanddelicious. Whiletomatoloversdon’’tneedanexcuseforeatingthembythebushel蒲式耳nowthere’’sevenmorereasontosavorthesedeliciousfruits.Evidenceismountingthatpeoplewhoeattomatoeshaveasubstantiallylowerriskforcancer. Inathousand-personstudyofeatinghabitsandhealthHarvardMedicalSchoolresearchersfoundthatthosewhoatetomatoeseveryweekhadthelowestchanceofdyingformcancer. Recentlyastudyof48000Americanmenshoweda21to34percentlowerriskforprostatecancer前列腺癌amongthosewhoconsumedtomatoestomatosauceorpizzamorethantwiceaweek.AndinstudyofmenandwomeninItalyeatingsevenormoreservingofrawtomatoesaweekwaslinkedtoa30to60percentreductionindigestivetractandprostatecancersdependingonthetypeofcancer. Theprotectivequalitiesofthetomatoarethoughttocomefromlycopene番茄红素apotentantioxidant抗氧化的plantchemicalthatisabundantintomatoes.Lycopeneisresponsiblefortheredcoloroftomatoes;thedarkerredthetomatoisthemorelycopeneitcontains.Greenandyellowtomatoesdonotcontainlycopene. Lycopoeneisalsofoundinwatermelonandpinkgrapefruitbuttomatoesarethemostabundantsource.Cookingenhancesthelycopenemoreavailable.Thustomatosauceandpasteisevenabettersourceforlycopenethanfreshrawtomatoes.Lycopeneisfatsolubleandmustbeconsumedwithacertainamountoffattobeabsorbedbythebody.Tomatorecipesmustcontainamoderateamountofoiltoensurethatalongwithadelicioustastetreatyouwillalsobereceivingallthehealthbenefitstomatoeshavetooffer. Inordertobeabsorbedbybody______.
DefectiveGenesandHumanHealth Eachofuscarriesabouthalfadozendefective有缺点的genes.Weremainblissfully快乐地unawareofthisfactunlessweoroneofourcloserelativesareamongstthemanymillionswhosufferfromageneticdisease.Aboutoneintenpeoplehasorwilldevelopatsomelaterstageaninherited遗传的geneticdisorderandapproximately2800specificconditionsareknowntobecausedbydefectsmutationsinjustoneofthepatient’’sgenes.Somesinglegenedisordersarequitecommon-—cystic胞状的fibrosis纤维化isfoundinoneoutofevery2500babiesbornintheWesternWorld—andintotaldiseasesthatcanbetracedtosinglegenedefectsaccountforabout5%ofalladmissionstochildren’’shospitals. Mostofusdonotsufferanyharmfuleffectsfromourdefectivegenesbecausewecarrytwocopiesofnearlyallgenesonederivedfromourmotherandtheotherfromourfather.Theonlyexceptionstothisrulearethegenesfoundonthemalesexchromosomes染色体MaleshaveoneXandoneYchromosometheformerfromthemotherandthelatterfromthefathersoeachcellhasonlyonecopyofthegenesonthesechromosomes.Inthemajorityofcasesonenormalgeneissufficienttoavoidallthesymptomsofdisease.Ifthepotentiallyharmfulgeneisrecessive后退的thenitsnormalcounterpart配对的willcarryoutallthetasksassignedtoboth.Onlyifweinheritfromourparentstwocopiesofthesamerecessivegenewilladiseasedevelop. Ontheotherhandifthegeneisdominant显性的italonecanproducethediseaseevenifitscounterpartisnormal.Clearlyonlythechildrenofaparentwiththediseasecanbeaffectedandthenaverageonlyhalfthechildrenwillbeaffected.Huntington’’schorea舞蹈病aseverediseaseofthenervoussystemwhichbecomesapparentonlyinadulthoodisanexampleofadominantgeneticdisease. FinallytherearetheXchromosome-linkedgeneticdiseases.Asmaleshaveonlyonecopyofthegenesfromthischromosometherearenoothersavailabletofulfillthedefectivegene’’sfunction.ExamplesofsuchdiseasesareDuchennemusculardystrophy营养不良andperhapsmostwellknownofallhemophilia血友病. QueenVictoriawasacarrierofthedefectivegeneresponsibleforhemophiliaandthroughheritwastransmittedtotheroyalfamiliesofRussiaSpainandPrussia.MinorcutsandbruiseswhichwoulddolittleharmtomostpeoplecanprovefataltohemophiliacswholacktheproteinsFactorsVIIIandIV凝血因子VIII和IVinvolvedintheclotting血凝结ofbloodwhicharecodedforbythedefectivegenes.Sadlybeforetheseproteinsweremadeavailablethroughgeneticengineeringhemophiliacsweretreatedwithproteinsisolatedfromhumanblood.Someofthisbloodwascontaminated污损withtheAIDSvirusandhasresultedintragic悲惨的consequencesformanyhemophiliacs.Useofgeneticallyengineeredproteinsintherapeuticapplicationsratherthanbloodproductswillavoidtheseproblemsinthefuture. Notalldefectivegenesnecessarilyproducedetrimental有害的effectssincetheenvironmentinwhichthegeneoperatesisalsoofimportance.Aclassicexampleofageneticdiseasehavingabeneficialeffectonsurvivalisillustratedbytherelationshipbetweensickle-cell镶形血球anemia贫血症andmalaria疟病.Onlyindividualshavingtwocopiesofthesickle-cellgeneandonenormalgeneareunaffectedandmoreimportantlyareabletoresistinfection传染bymalarialparasites寄生虫.Theclearadvantageinthiscaseofhavingonedefectivegeneexplainswhythisgeneiscommoninpopulationsinthoseareasoftheworldwheremalariaisendemic特有的. thediseasepara.7refersto______.
HeartAttack IntheUnitedStatesandespeciallyinbigcitiesandruralareastensofthousandsofpeoplewithheartsthatshouldbegood【51】tokeepthemalivedieeachyearforlackofadequatefirstaid.InNewYorkCityforexampleanewstudyhasshownthatonlyonepersonin100outsideofhospitals【52】aftertheheartsuddenlystopspumping.IncontrastinSeattlethesurvival【53】aftersuchheartattacksisoneinfive. Thedifferencecanbetraced【54】theeffectivenessofthechainofsurvivalDr.JosephP.Ornatosaid.Eachlinkinthe【55】mustbestrongenoughformanylivestobe【56】. Thechainbeginswithanimmediatetelephone【57】foremergencyhelpandthestartwithinfourminutesoftheprocessneededforrestartingthe【58】workingbyafamilymemberorbystander旁观者. Itcontinueswiththepromptarrival-------withineight【59】tenminutesofarescuerequippedwithaspecialinstrumentthatcanshocktheheartbacktoanormalrhythm.Anditendswiththeadministration给予实施ofadvanced先进emergencycarebynursestomaintaintheheart’’sabilitytosurviveuntilthedoctorsatthehospitalscantake【60】Whenoneormorelinksinthischainfailorfunctiontooslowlythe【61】ofavictimsurvivingheartattackfallsrapidly.Becauseofwidespreadweaknessesinthechainof【62】expertsinemergencyheartcareestimatethat20000to80000people【63】needlesslyofheartattackeachyearanumbercomparabletothe55000killedannuallyinautomobile【64】. OneexpertsaysSendinganemergencyvehicletoaheartattackvictim【65】thespecialequipmentislikehavingpolicemenwithgunsbutnobullets.Theymayputonagoodshowbuttheylacktheweaponneededtogetthejobdone.
Interferon Forseveralyearsscientistshavebeentestingasubstancecalledinterferon干扰素apotentialwonderdrugthatisprovingtobeeffectiveintreatingavarietyofailmentsincludingvirusinfectionsbacteriainfectionsandtumors.Todatethenewdrughasprovokednonegativereactionofsufficientsignificancetodiscourageitsuse.Butinspiteofitssuccesslastyearonlyonegramwasproducedintheentireworld. Thereasonforthescarcityliesinthestructureofinterferon.Aspeciesspecificproteintheinterferonproducedfromoneanimalspeciescannotbeusedintreatinganotheranimalspecies.Inotherwordstotreathumanbeingsonlyinterferonproducedbyhumanbeingsmaybeused.Thedrugisproducedbyinfectingwhitebloodcellswithavirus.Fortunatelyitissopotentthattheamountgiveneachpatientperinjectionisverysmall. Unlikeantibiotics抗菌素interferondoesnotattackgermsdirectly.Insteaditmakesunaffectedcellsresistanttoinfectionandpreventsthemultiplicationofviruseswithincells. Asyoumightconcludeoneofthemostdramaticusesofinterferonhasbeeninthetreatmentofcancer.Dr.HansStranderresearchphysicianatSweden’’sfamousKarolinskaInstitutehastreatedmorethanonehundredcancerpatientswiththenewdrug.Amongagroupofselectedpatientswhohadundergonesurgicalproceduresforadvancedcancerhalfweregivenconventionaltreatmentsandtheotherhalfweregiveninterferon.Thesurvivalrateoverathree-yearperiodwas70percentamongthosewhoweretreatedwithinterferonascomparedwithonly10to30percentamongthosewhohadreceivedtheconventionaltreatments. IntheUnitedStatesalarge-scaleprojectsupportedbytheAmericanCancerSocietyisnowunderway.Iftheexperimentissuccessfulinterferoncouldbecomeoneofthegreatestmedicaldiscoveriesofourtime. Interferonhasnotbeenwidelyusedbecauseitisstillverydangerous.
Thetechniciansconductedinvestigationsbeforetheyputforwardthesuggestionsatthemeeting.
Thedevelopmentofthetransistorandintegratedcircuitsrevolutionizedtheelectronicsindustrybyallowingcomponentstobepackagedmoredensely.
OnAntibodies Substancesforeigntothebodysuchasdisease-causingbacteriaandvirusesandotherinfectiousagentsarerecognizedbythebodysimmunesystemasinvaders.Ournaturaldefensesagainsttheseinfectiousagentsareantibodiesproteinsthatseekouttheantigens抗原andhelpdestroythem. Antibodieshavetwoveryusefulcharacteristics.Firsttheyareextremelyspecific;thatiseachantibodybindstoandattacksoneparticularantigen.Secondsomeantibodiesonceactivatedbytheoccurrenceofadiseasecontinuetoconferresistanceagainstthatdisease.Classicexamplearetheantibodiestothechildhooddiseasesofchickenpox水痘andmeasles. Thesecondcharacteristicofantibodiesmakesitpossibletodevelopvaccines.Avaccine痘苗isapreparationofkilledorweakenedbacteriaorvirusesthatwhenintroducedintothebodystimulatestheproductionofantibodiesagainsttheantigensitcontains. Itisthefirsttraitofantibodiestheirspecificitythatmakesmonoclonalantibodytechnologysovaluable.Notonlycanantibodiesbeusedtherapeutically在治疗上toprotectagainstdisease;theycanalsohelpto.diagnoseawidevarietyofillnessesandcandetectthepresenceofdrugsviralandbacterialproductsandotherunusualorabnormalsubstancesintheblood. Givensuchadiversityofusesforthesediseased-fightingsubstancestheirproductioninpurequantitieshaslongbeenthefocusofscientificinvestigation.Theconventionalmethodwastoinjectalaboratoryanimalwithanantigenandthenafterantibodieshadbeenformedcollectthoseantibodiesfromthebloodserum血清Antibodycontainingbloodserumiscalledantiserum抗血清.Therearetwoproblemswiththismethod:Ityieldsantiserumthatcontainsundesiredsubstancesanditprovidesaverysmallamountofusableantibody. Monoclonalantibodytechnologyallowsustoproducelargeamountsofpureantibodies.inthefollowingway:wecanobtaincellsthatproduceantibodiesnaturally;wealsohaveavailableaclassofcellsthatcangrowcontinuallyincellculture培养.Ifweformahybrid混血儿thatcombinesthecharacteristicofimmortality永生withtheabilitytoproducethedesiredsubstancewewouldhaveineffectafactorytoproduceantibodiesthatworkaroundtheclock. Inmonoclonalantibodytechnologytumorcellsthatcanreplicate重复endlesslyarefusedwithmammaliancellsthatproduceanantibody.Theresultofthiscellfusionisahybridoma杂交瘤whichwillcontinuallyproduceantibodies.Theseantibodiesarecalledmonoclonalbecausetheycomefromonlyonetypeofcellthehybridomacell;antibodiesproducedbyconventionalmethodsontheotherhandarederivedfrompreparationscontainingmanykindsofcellsandhencearecalledpolyclonal.Anexampleofhowmonoclonalantibodiesarederivedisdescribedbelow. Amyelomaisatumorofthebonemarrow骨髓thatcanbeadaptedtogrowpermanendyincellculture.Whenmyelomacellswerefusedwithantibody-producingmammalianspleencellsitwasfoundthattheresultinghybridcellsorhybridomasproducedlargeamountsofmonoclonal骨髓瘤antibody.Thisproductofcellfusioncombinedthedesiredqualitiesofthetwodifferenttypesofcells:theabilitytogrowcontinuallyandtheabilitytoproducelargeamountsofpureantibody. Becauseselectedhybridcellsproduceonlyonespecificantibodytheyaremorepurethanthepolyclonalantibodiesproducedbyconventionaltechniques.Theyarepotentiallymoreeffectivethanconventionaldrugsinfightingdiseasesincedrugsattacknotonlytheforeignsubstancebutthebody’sowncellsaswellsometimesproducingundesirablesideeffectssuchasnausea恶心andallergicreactions.Monoclonalantibodiesattackthetargetmoleculeandonlythetargetmoleculewithnoorgreatlydiminishedsideeffects. Whichofthefollowingsubstancesisnotaninvadertothebody’simmunesystem?
DefectiveGenesandHumanHealth Eachofuscarriesabouthalfadozendefective有缺点的genes.Weremainblissfully快乐地unawareofthisfactunlessweoroneofourcloserelativesareamongstthemanymillionswhosufferfromageneticdisease.Aboutoneintenpeoplehasorwilldevelopatsomelaterstageaninherited遗传的geneticdisorderandapproximately2800specificconditionsareknowntobecausedbydefectsmutationsinjustoneofthepatient’’sgenes.Somesinglegenedisordersarequitecommon-—cystic胞状的fibrosis纤维化isfoundinoneoutofevery2500babiesbornintheWesternWorld—andintotaldiseasesthatcanbetracedtosinglegenedefectsaccountforabout5%ofalladmissionstochildren’’shospitals. Mostofusdonotsufferanyharmfuleffectsfromourdefectivegenesbecausewecarrytwocopiesofnearlyallgenesonederivedfromourmotherandtheotherfromourfather.Theonlyexceptionstothisrulearethegenesfoundonthemalesexchromosomes染色体MaleshaveoneXandoneYchromosometheformerfromthemotherandthelatterfromthefathersoeachcellhasonlyonecopyofthegenesonthesechromosomes.Inthemajorityofcasesonenormalgeneissufficienttoavoidallthesymptomsofdisease.Ifthepotentiallyharmfulgeneisrecessive后退的thenitsnormalcounterpart配对的willcarryoutallthetasksassignedtoboth.Onlyifweinheritfromourparentstwocopiesofthesamerecessivegenewilladiseasedevelop. Ontheotherhandifthegeneisdominant显性的italonecanproducethediseaseevenifitscounterpartisnormal.Clearlyonlythechildrenofaparentwiththediseasecanbeaffectedandthenaverageonlyhalfthechildrenwillbeaffected.Huntington’’schorea舞蹈病aseverediseaseofthenervoussystemwhichbecomesapparentonlyinadulthoodisanexampleofadominantgeneticdisease. FinallytherearetheXchromosome-linkedgeneticdiseases.Asmaleshaveonlyonecopyofthegenesfromthischromosometherearenoothersavailabletofulfillthedefectivegene’’sfunction.ExamplesofsuchdiseasesareDuchennemusculardystrophy营养不良andperhapsmostwellknownofallhemophilia血友病. QueenVictoriawasacarrierofthedefectivegeneresponsibleforhemophiliaandthroughheritwastransmittedtotheroyalfamiliesofRussiaSpainandPrussia.MinorcutsandbruiseswhichwoulddolittleharmtomostpeoplecanprovefataltohemophiliacswholacktheproteinsFactorsVIIIandIV凝血因子VIII和IVinvolvedintheclotting血凝结ofbloodwhicharecodedforbythedefectivegenes.Sadlybeforetheseproteinsweremadeavailablethroughgeneticengineeringhemophiliacsweretreatedwithproteinsisolatedfromhumanblood.Someofthisbloodwascontaminated污损withtheAIDSvirusandhasresultedintragic悲惨的consequencesformanyhemophiliacs.Useofgeneticallyengineeredproteinsintherapeuticapplicationsratherthanbloodproductswillavoidtheseproblemsinthefuture. Notalldefectivegenesnecessarilyproducedetrimental有害的effectssincetheenvironmentinwhichthegeneoperatesisalsoofimportance.Aclassicexampleofageneticdiseasehavingabeneficialeffectonsurvivalisillustratedbytherelationshipbetweensickle-cell镶形血球anemia贫血症andmalaria疟病.Onlyindividualshavingtwocopiesofthesickle-cellgeneandonenormalgeneareunaffectedandmoreimportantlyareabletoresistinfection传染bymalarialparasites寄生虫.Theclearadvantageinthiscaseofhavingonedefectivegeneexplainswhythisgeneiscommoninpopulationsinthoseareasoftheworldwheremalariaisendemic特有的. Wecaninferfrompara.4that______.
TheshortstoriesofKatherineMansfielddemonstrateherkeenperceptionsofhumancharacter.
NewTechniquePromisesEarlierCancerDetection AnewtechniquecouldrevolutionizetheearlydetectionofcancergivingsufferersagreaterchanceofbeatingthediseaseAmericanscientistssaid.ResearchersattheMassachusettsInstituteofTechnologyhavedevisedanovelmethodof【51】changesinthenucleusofcellsintheearlieststagesofthedisease.Morethan85percentofallcancersoriginateintheepithelium上皮thatlinestheinternalsurfacesoforgans【52】thebody.Althoughthesearetreatable【53】theyarediagnosedinoneofthepreventablestagesearlybodydamagesarealmost【54】todetectsaidscientistFeld.Wepresentanewoptical-probe光学探子techniquebasedonlight-scatteringspectroscopy分光镜检查thatisable【55】detectprecancerousandearlycancerouscellsincell-richepitheliaheaddedinastatement. Thenewtechniquereliesonthefact【56】cellnucleichangeintheearlystagesofcancerandthedifferencesscatterlightinacharacteristicway.Untilnowthechangeswereonlydetectable【57】abiopsy活检wastakenthescientistssaid.Thenewtechnique【58】inthesciencejournalNaturecanbeusedinconjunctionwitharoutinecancerscreeningandsurveillancetechniquewhichusesanendoscope内窥镜—aflexibleopticalprobe【59】withcameraswhichisinsertedintoacavityinthebody—tocheck【60】cancers. Thescientistssaidthey【61】theirnewtechniqueinfourdifferentorgansduringroutineendoscopiccancerscreening.Thetipoftheopticalprobewasbroughtintocontactwiththetissuetobetestedandthescatteringoflightwasrecordedwithouttheneedforanytissuetobe【62】thescientistssaid.Ourresultsshowthatlight-scatteringspectroscopyhasthepotentialtodetectpre-cancerousbodydamagesandpreinvasivecancersthroughoutthebody.Thistechniqueshould【63】improvetheefficiencyofcancerscreeningandsurveillancethescientistssaid.Cancerisoneofthebiggest【64】inindustrializedcountries.【65】tofiguresfromtheWorldHealthOrganization10millionpeoplewerediagnosedwiththediseaseworldwidein1997andsixmilliondied.
Thecollegeofferscoursesinavarietyoftrades.
Interferon Forseveralyearsscientistshavebeentestingasubstancecalledinterferon干扰素apotentialwonderdrugthatisprovingtobeeffectiveintreatingavarietyofailmentsincludingvirusinfectionsbacteriainfectionsandtumors.Todatethenewdrughasprovokednonegativereactionofsufficientsignificancetodiscourageitsuse.Butinspiteofitssuccesslastyearonlyonegramwasproducedintheentireworld. Thereasonforthescarcityliesinthestructureofinterferon.Aspeciesspecificproteintheinterferonproducedfromoneanimalspeciescannotbeusedintreatinganotheranimalspecies.Inotherwordstotreathumanbeingsonlyinterferonproducedbyhumanbeingsmaybeused.Thedrugisproducedbyinfectingwhitebloodcellswithavirus.Fortunatelyitissopotentthattheamountgiveneachpatientperinjectionisverysmall. Unlikeantibiotics抗菌素interferondoesnotattackgermsdirectly.Insteaditmakesunaffectedcellsresistanttoinfectionandpreventsthemultiplicationofviruseswithincells. Asyoumightconcludeoneofthemostdramaticusesofinterferonhasbeeninthetreatmentofcancer.Dr.HansStranderresearchphysicianatSweden’’sfamousKarolinskaInstitutehastreatedmorethanonehundredcancerpatientswiththenewdrug.Amongagroupofselectedpatientswhohadundergonesurgicalproceduresforadvancedcancerhalfweregivenconventionaltreatmentsandtheotherhalfweregiveninterferon.Thesurvivalrateoverathree-yearperiodwas70percentamongthosewhoweretreatedwithinterferonascomparedwithonly10to30percentamongthosewhohadreceivedtheconventionaltreatments. IntheUnitedStatesalarge-scaleprojectsupportedbytheAmericanCancerSocietyisnowunderway.Iftheexperimentissuccessfulinterferoncouldbecomeoneofthegreatestmedicaldiscoveriesofourtime. Theeffectinterferonhasoninfectionisthatitkeepshealthycellsfrombecominginfected.
Interferon Forseveralyearsscientistshavebeentestingasubstancecalledinterferon干扰素apotentialwonderdrugthatisprovingtobeeffectiveintreatingavarietyofailmentsincludingvirusinfectionsbacteriainfectionsandtumors.Todatethenewdrughasprovokednonegativereactionofsufficientsignificancetodiscourageitsuse.Butinspiteofitssuccesslastyearonlyonegramwasproducedintheentireworld. Thereasonforthescarcityliesinthestructureofinterferon.Aspeciesspecificproteintheinterferonproducedfromoneanimalspeciescannotbeusedintreatinganotheranimalspecies.Inotherwordstotreathumanbeingsonlyinterferonproducedbyhumanbeingsmaybeused.Thedrugisproducedbyinfectingwhitebloodcellswithavirus.Fortunatelyitissopotentthattheamountgiveneachpatientperinjectionisverysmall. Unlikeantibiotics抗菌素interferondoesnotattackgermsdirectly.Insteaditmakesunaffectedcellsresistanttoinfectionandpreventsthemultiplicationofviruseswithincells. Asyoumightconcludeoneofthemostdramaticusesofinterferonhasbeeninthetreatmentofcancer.Dr.HansStranderresearchphysicianatSweden’’sfamousKarolinskaInstitutehastreatedmorethanonehundredcancerpatientswiththenewdrug.Amongagroupofselectedpatientswhohadundergonesurgicalproceduresforadvancedcancerhalfweregivenconventionaltreatmentsandtheotherhalfweregiveninterferon.Thesurvivalrateoverathree-yearperiodwas70percentamongthosewhoweretreatedwithinterferonascomparedwithonly10to30percentamongthosewhohadreceivedtheconventionaltreatments. IntheUnitedStatesalarge-scaleprojectsupportedbytheAmericanCancerSocietyisnowunderway.Iftheexperimentissuccessfulinterferoncouldbecomeoneofthegreatestmedicaldiscoveriesofourtime. 21Interferoncauseshealthycellstogrow.
Themachinemustbeoperatedbyhand.Itisn’’tautomatic.
NewTechniquePromisesEarlierCancerDetection AnewtechniquecouldrevolutionizetheearlydetectionofcancergivingsufferersagreaterchanceofbeatingthediseaseAmericanscientistssaid.ResearchersattheMassachusettsInstituteofTechnologyhavedevisedanovelmethodof【51】changesinthenucleusofcellsintheearlieststagesofthedisease.Morethan85percentofallcancersoriginateintheepithelium上皮thatlinestheinternalsurfacesoforgans【52】thebody.Althoughthesearetreatable【53】theyarediagnosedinoneofthepreventablestagesearlybodydamagesarealmost【54】todetectsaidscientistFeld.Wepresentanewoptical-probe光学探子techniquebasedonlight-scatteringspectroscopy分光镜检查thatisable【55】detectprecancerousandearlycancerouscellsincell-richepitheliaheaddedinastatement. Thenewtechniquereliesonthefact【56】cellnucleichangeintheearlystagesofcancerandthedifferencesscatterlightinacharacteristicway.Untilnowthechangeswereonlydetectable【57】abiopsy活检wastakenthescientistssaid.Thenewtechnique【58】inthesciencejournalNaturecanbeusedinconjunctionwitharoutinecancerscreeningandsurveillancetechniquewhichusesanendoscope内窥镜—aflexibleopticalprobe【59】withcameraswhichisinsertedintoacavityinthebody—tocheck【60】cancers. Thescientistssaidthey【61】theirnewtechniqueinfourdifferentorgansduringroutineendoscopiccancerscreening.Thetipoftheopticalprobewasbroughtintocontactwiththetissuetobetestedandthescatteringoflightwasrecordedwithouttheneedforanytissuetobe【62】thescientistssaid.Ourresultsshowthatlight-scatteringspectroscopyhasthepotentialtodetectpre-cancerousbodydamagesandpreinvasivecancersthroughoutthebody.Thistechniqueshould【63】improvetheefficiencyofcancerscreeningandsurveillancethescientistssaid.Cancerisoneofthebiggest【64】inindustrializedcountries.【65】tofiguresfromtheWorldHealthOrganization10millionpeoplewerediagnosedwiththediseaseworldwidein1997andsixmilliondied.
NewTechniquePromisesEarlierCancerDetection AnewtechniquecouldrevolutionizetheearlydetectionofcancergivingsufferersagreaterchanceofbeatingthediseaseAmericanscientistssaid.ResearchersattheMassachusettsInstituteofTechnologyhavedevisedanovelmethodof【51】changesinthenucleusofcellsintheearlieststagesofthedisease.Morethan85percentofallcancersoriginateintheepithelium上皮thatlinestheinternalsurfacesoforgans【52】thebody.Althoughthesearetreatable【53】theyarediagnosedinoneofthepreventablestagesearlybodydamagesarealmost【54】todetectsaidscientistFeld.Wepresentanewoptical-probe光学探子techniquebasedonlight-scatteringspectroscopy分光镜检查thatisable【55】detectprecancerousandearlycancerouscellsincell-richepitheliaheaddedinastatement. Thenewtechniquereliesonthefact【56】cellnucleichangeintheearlystagesofcancerandthedifferencesscatterlightinacharacteristicway.Untilnowthechangeswereonlydetectable【57】abiopsy活检wastakenthescientistssaid.Thenewtechnique【58】inthesciencejournalNaturecanbeusedinconjunctionwitharoutinecancerscreeningandsurveillancetechniquewhichusesanendoscope内窥镜—aflexibleopticalprobe【59】withcameraswhichisinsertedintoacavityinthebody—tocheck【60】cancers. Thescientistssaidthey【61】theirnewtechniqueinfourdifferentorgansduringroutineendoscopiccancerscreening.Thetipoftheopticalprobewasbroughtintocontactwiththetissuetobetestedandthescatteringoflightwasrecordedwithouttheneedforanytissuetobe【62】thescientistssaid.Ourresultsshowthatlight-scatteringspectroscopyhasthepotentialtodetectpre-cancerousbodydamagesandpreinvasivecancersthroughoutthebody.Thistechniqueshould【63】improvetheefficiencyofcancerscreeningandsurveillancethescientistssaid.Cancerisoneofthebiggest【64】inindustrializedcountries.【65】tofiguresfromtheWorldHealthOrganization10millionpeoplewerediagnosedwiththediseaseworldwidein1997andsixmilliondied.
DefectiveGenesandHumanHealth Eachofuscarriesabouthalfadozendefective有缺点的genes.Weremainblissfully快乐地unawareofthisfactunlessweoroneofourcloserelativesareamongstthemanymillionswhosufferfromageneticdisease.Aboutoneintenpeoplehasorwilldevelopatsomelaterstageaninherited遗传的geneticdisorderandapproximately2800specificconditionsareknowntobecausedbydefectsmutationsinjustoneofthepatient’’sgenes.Somesinglegenedisordersarequitecommon-—cystic胞状的fibrosis纤维化isfoundinoneoutofevery2500babiesbornintheWesternWorld—andintotaldiseasesthatcanbetracedtosinglegenedefectsaccountforabout5%ofalladmissionstochildren’’shospitals. Mostofusdonotsufferanyharmfuleffectsfromourdefectivegenesbecausewecarrytwocopiesofnearlyallgenesonederivedfromourmotherandtheotherfromourfather.Theonlyexceptionstothisrulearethegenesfoundonthemalesexchromosomes染色体MaleshaveoneXandoneYchromosometheformerfromthemotherandthelatterfromthefathersoeachcellhasonlyonecopyofthegenesonthesechromosomes.Inthemajorityofcasesonenormalgeneissufficienttoavoidallthesymptomsofdisease.Ifthepotentiallyharmfulgeneisrecessive后退的thenitsnormalcounterpart配对的willcarryoutallthetasksassignedtoboth.Onlyifweinheritfromourparentstwocopiesofthesamerecessivegenewilladiseasedevelop. Ontheotherhandifthegeneisdominant显性的italonecanproducethediseaseevenifitscounterpartisnormal.Clearlyonlythechildrenofaparentwiththediseasecanbeaffectedandthenaverageonlyhalfthechildrenwillbeaffected.Huntington’’schorea舞蹈病aseverediseaseofthenervoussystemwhichbecomesapparentonlyinadulthoodisanexampleofadominantgeneticdisease. FinallytherearetheXchromosome-linkedgeneticdiseases.Asmaleshaveonlyonecopyofthegenesfromthischromosometherearenoothersavailabletofulfillthedefectivegene’’sfunction.ExamplesofsuchdiseasesareDuchennemusculardystrophy营养不良andperhapsmostwellknownofallhemophilia血友病. QueenVictoriawasacarrierofthedefectivegeneresponsibleforhemophiliaandthroughheritwastransmittedtotheroyalfamiliesofRussiaSpainandPrussia.MinorcutsandbruiseswhichwoulddolittleharmtomostpeoplecanprovefataltohemophiliacswholacktheproteinsFactorsVIIIandIV凝血因子VIII和IVinvolvedintheclotting血凝结ofbloodwhicharecodedforbythedefectivegenes.Sadlybeforetheseproteinsweremadeavailablethroughgeneticengineeringhemophiliacsweretreatedwithproteinsisolatedfromhumanblood.Someofthisbloodwascontaminated污损withtheAIDSvirusandhasresultedintragic悲惨的consequencesformanyhemophiliacs.Useofgeneticallyengineeredproteinsintherapeuticapplicationsratherthanbloodproductswillavoidtheseproblemsinthefuture. Notalldefectivegenesnecessarilyproducedetrimental有害的effectssincetheenvironmentinwhichthegeneoperatesisalsoofimportance.Aclassicexampleofageneticdiseasehavingabeneficialeffectonsurvivalisillustratedbytherelationshipbetweensickle-cell镶形血球anemia贫血症andmalaria疟病.Onlyindividualshavingtwocopiesofthesickle-cellgeneandonenormalgeneareunaffectedandmoreimportantlyareabletoresistinfection传染bymalarialparasites寄生虫.Theclearadvantageinthiscaseofhavingonedefectivegeneexplainswhythisgeneiscommoninpopulationsinthoseareasoftheworldwheremalariaisendemic特有的. WhichofthefollowingstatementsongenesanddiseasesisNOTTRUE?
Thetownisfamousforitsmagnificentchurchtowers.
NewTechniquePromisesEarlierCancerDetection AnewtechniquecouldrevolutionizetheearlydetectionofcancergivingsufferersagreaterchanceofbeatingthediseaseAmericanscientistssaid.ResearchersattheMassachusettsInstituteofTechnologyhavedevisedanovelmethodof【51】changesinthenucleusofcellsintheearlieststagesofthedisease.Morethan85percentofallcancersoriginateintheepithelium上皮thatlinestheinternalsurfacesoforgans【52】thebody.Althoughthesearetreatable【53】theyarediagnosedinoneofthepreventablestagesearlybodydamagesarealmost【54】todetectsaidscientistFeld.Wepresentanewoptical-probe光学探子techniquebasedonlight-scatteringspectroscopy分光镜检查thatisable【55】detectprecancerousandearlycancerouscellsincell-richepitheliaheaddedinastatement. Thenewtechniquereliesonthefact【56】cellnucleichangeintheearlystagesofcancerandthedifferencesscatterlightinacharacteristicway.Untilnowthechangeswereonlydetectable【57】abiopsy活检wastakenthescientistssaid.Thenewtechnique【58】inthesciencejournalNaturecanbeusedinconjunctionwitharoutinecancerscreeningandsurveillancetechniquewhichusesanendoscope内窥镜—aflexibleopticalprobe【59】withcameraswhichisinsertedintoacavityinthebody—tocheck【60】cancers. Thescientistssaidthey【61】theirnewtechniqueinfourdifferentorgansduringroutineendoscopiccancerscreening.Thetipoftheopticalprobewasbroughtintocontactwiththetissuetobetestedandthescatteringoflightwasrecordedwithouttheneedforanytissuetobe【62】thescientistssaid.Ourresultsshowthatlight-scatteringspectroscopyhasthepotentialtodetectpre-cancerousbodydamagesandpreinvasivecancersthroughoutthebody.Thistechniqueshould【63】improvetheefficiencyofcancerscreeningandsurveillancethescientistssaid.Cancerisoneofthebiggest【64】inindustrializedcountries.【65】tofiguresfromtheWorldHealthOrganization10millionpeoplewerediagnosedwiththediseaseworldwidein1997andsixmilliondied.
OnAntibodies Substancesforeigntothebodysuchasdisease-causingbacteriaandvirusesandotherinfectiousagentsarerecognizedbythebodysimmunesystemasinvaders.Ournaturaldefensesagainsttheseinfectiousagentsareantibodiesproteinsthatseekouttheantigens抗原andhelpdestroythem. Antibodieshavetwoveryusefulcharacteristics.Firsttheyareextremelyspecific;thatiseachantibodybindstoandattacksoneparticularantigen.Secondsomeantibodiesonceactivatedbytheoccurrenceofadiseasecontinuetoconferresistanceagainstthatdisease.Classicexamplearetheantibodiestothechildhooddiseasesofchickenpox水痘andmeasles. Thesecondcharacteristicofantibodiesmakesitpossibletodevelopvaccines.Avaccine痘苗isapreparationofkilledorweakenedbacteriaorvirusesthatwhenintroducedintothebodystimulatestheproductionofantibodiesagainsttheantigensitcontains. Itisthefirsttraitofantibodiestheirspecificitythatmakesmonoclonalantibodytechnologysovaluable.Notonlycanantibodiesbeusedtherapeutically在治疗上toprotectagainstdisease;theycanalsohelpto.diagnoseawidevarietyofillnessesandcandetectthepresenceofdrugsviralandbacterialproductsandotherunusualorabnormalsubstancesintheblood. Givensuchadiversityofusesforthesediseased-fightingsubstancestheirproductioninpurequantitieshaslongbeenthefocusofscientificinvestigation.Theconventionalmethodwastoinjectalaboratoryanimalwithanantigenandthenafterantibodieshadbeenformedcollectthoseantibodiesfromthebloodserum血清Antibodycontainingbloodserumiscalledantiserum抗血清.Therearetwoproblemswiththismethod:Ityieldsantiserumthatcontainsundesiredsubstancesanditprovidesaverysmallamountofusableantibody. Monoclonalantibodytechnologyallowsustoproducelargeamountsofpureantibodies.inthefollowingway:wecanobtaincellsthatproduceantibodiesnaturally;wealsohaveavailableaclassofcellsthatcangrowcontinuallyincellculture培养.Ifweformahybrid混血儿thatcombinesthecharacteristicofimmortality永生withtheabilitytoproducethedesiredsubstancewewouldhaveineffectafactorytoproduceantibodiesthatworkaroundtheclock. Inmonoclonalantibodytechnologytumorcellsthatcanreplicate重复endlesslyarefusedwithmammaliancellsthatproduceanantibody.Theresultofthiscellfusionisahybridoma杂交瘤whichwillcontinuallyproduceantibodies.Theseantibodiesarecalledmonoclonalbecausetheycomefromonlyonetypeofcellthehybridomacell;antibodiesproducedbyconventionalmethodsontheotherhandarederivedfrompreparationscontainingmanykindsofcellsandhencearecalledpolyclonal.Anexampleofhowmonoclonalantibodiesarederivedisdescribedbelow. Amyelomaisatumorofthebonemarrow骨髓thatcanbeadaptedtogrowpermanendyincellculture.Whenmyelomacellswerefusedwithantibody-producingmammalianspleencellsitwasfoundthattheresultinghybridcellsorhybridomasproducedlargeamountsofmonoclonal骨髓瘤antibody.Thisproductofcellfusioncombinedthedesiredqualitiesofthetwodifferenttypesofcells:theabilitytogrowcontinuallyandtheabilitytoproducelargeamountsofpureantibody. Becauseselectedhybridcellsproduceonlyonespecificantibodytheyaremorepurethanthepolyclonalantibodiesproducedbyconventionaltechniques.Theyarepotentiallymoreeffectivethanconventionaldrugsinfightingdiseasesincedrugsattacknotonlytheforeignsubstancebutthebody’sowncellsaswellsometimesproducingundesirablesideeffectssuchasnausea恶心andallergicreactions.Monoclonalantibodiesattackthetargetmoleculeandonlythetargetmoleculewithnoorgreatlydiminishedsideeffects. WhichofthefollowingfunctionsdoneNOTbelongtoantibodies?
Itshardtoalteroneshabits.
NewTechniquePromisesEarlierCancerDetection AnewtechniquecouldrevolutionizetheearlydetectionofcancergivingsufferersagreaterchanceofbeatingthediseaseAmericanscientistssaid.ResearchersattheMassachusettsInstituteofTechnologyhavedevisedanovelmethodof【51】changesinthenucleusofcellsintheearlieststagesofthedisease.Morethan85percentofallcancersoriginateintheepithelium上皮thatlinestheinternalsurfacesoforgans【52】thebody.Althoughthesearetreatable【53】theyarediagnosedinoneofthepreventablestagesearlybodydamagesarealmost【54】todetectsaidscientistFeld.Wepresentanewoptical-probe光学探子techniquebasedonlight-scatteringspectroscopy分光镜检查thatisable【55】detectprecancerousandearlycancerouscellsincell-richepitheliaheaddedinastatement. Thenewtechniquereliesonthefact【56】cellnucleichangeintheearlystagesofcancerandthedifferencesscatterlightinacharacteristicway.Untilnowthechangeswereonlydetectable【57】abiopsy活检wastakenthescientistssaid.Thenewtechnique【58】inthesciencejournalNaturecanbeusedinconjunctionwitharoutinecancerscreeningandsurveillancetechniquewhichusesanendoscope内窥镜—aflexibleopticalprobe【59】withcameraswhichisinsertedintoacavityinthebody—tocheck【60】cancers. Thescientistssaidthey【61】theirnewtechniqueinfourdifferentorgansduringroutineendoscopiccancerscreening.Thetipoftheopticalprobewasbroughtintocontactwiththetissuetobetestedandthescatteringoflightwasrecordedwithouttheneedforanytissuetobe【62】thescientistssaid.Ourresultsshowthatlight-scatteringspectroscopyhasthepotentialtodetectpre-cancerousbodydamagesandpreinvasivecancersthroughoutthebody.Thistechniqueshould【63】improvetheefficiencyofcancerscreeningandsurveillancethescientistssaid.Cancerisoneofthebiggest【64】inindustrializedcountries.【65】tofiguresfromtheWorldHealthOrganization10millionpeoplewerediagnosedwiththediseaseworldwidein1997andsixmilliondied.
TheFunctionofTomatoes Howdowelovetomatoes?Let’’scounttheways:welovetheminpastaonpizzainjuiceinsaladandsoupslicedonsandwichesstuffedwithtunaevendriedandbakedinbagelsbutmostofallwelovethemrightoffvine—riperedanddelicious. Whiletomatoloversdon’’tneedanexcuseforeatingthembythebushel蒲式耳nowthere’’sevenmorereasontosavorthesedeliciousfruits.Evidenceismountingthatpeoplewhoeattomatoeshaveasubstantiallylowerriskforcancer. Inathousand-personstudyofeatinghabitsandhealthHarvardMedicalSchoolresearchersfoundthatthosewhoatetomatoeseveryweekhadthelowestchanceofdyingformcancer. Recentlyastudyof48000Americanmenshoweda21to34percentlowerriskforprostatecancer前列腺癌amongthosewhoconsumedtomatoestomatosauceorpizzamorethantwiceaweek.AndinstudyofmenandwomeninItalyeatingsevenormoreservingofrawtomatoesaweekwaslinkedtoa30to60percentreductionindigestivetractandprostatecancersdependingonthetypeofcancer. Theprotectivequalitiesofthetomatoarethoughttocomefromlycopene番茄红素apotentantioxidant抗氧化的plantchemicalthatisabundantintomatoes.Lycopeneisresponsiblefortheredcoloroftomatoes;thedarkerredthetomatoisthemorelycopeneitcontains.Greenandyellowtomatoesdonotcontainlycopene. Lycopoeneisalsofoundinwatermelonandpinkgrapefruitbuttomatoesarethemostabundantsource.Cookingenhancesthelycopenemoreavailable.Thustomatosauceandpasteisevenabettersourceforlycopenethanfreshrawtomatoes.Lycopeneisfatsolubleandmustbeconsumedwithacertainamountoffattobeabsorbedbythebody.Tomatorecipesmustcontainamoderateamountofoiltoensurethatalongwithadelicioustastetreatyouwillalsobereceivingallthehealthbenefitstomatoeshavetooffer. Whatisthemainsubjectofthepassage?
NaturalMedicines Sinceearliestdayshumanshaveusedsomekindsofmedicines.Weknowthisbecausehumanshavesurvived.Ancienttreatmentsforinjuryanddiseaseweresuccessfulenoughtokeephumansfromdyingoutcompletely. Theyweresuccessfullongbeforethetimeofmodernmedicine.Beforethetimeofdoctorswithwhitecoatsandshiny发亮的instruments.Beforethetimeofbighospitalswithstrangeandwonderfulequipment. Manypartsoftheworldstilldonothaveuniversity-educateddoctors.Nordotheyhaveexpensivehospitals.Yetinjuriesaretreated.Anddiseasesareoftencured.How?Byancientmethods.Bymedicinesthatmightseemmysteriousevenmagical有魔力的.Traditionalmedicinesareneithermysteriousnormagicalhowever. Throughthecenturiestribal部落的medicinemenexperimentedwithplants.Theyfoundmanyusefulchemicalsintheplants.Andscientistsbelievemanyofthesetraditionalmedicinesmayprovidethecureforsomeoftoday’’smostseriousdiseases. Expertssayalmost80%ofthepeopleintheworlduseplantsforhealthcare.Thesenaturalmedicinesareusednotjustbecausepeoplehavenootherformoftreatment.Theyareusedbecausepeopletrustthem.Indevelopedareasfewpeoplethinkaboutthesourceofthemedicinestheybuyinastore.Yetmanywidely-usedmedicinesarefromancientsourcesespeciallyplants.Someexpertssaymorethan25%ofmodernmedicinescomeinonewayoranotherfromnature. Scientistshavelongknownthatnatureisreallyachemicalfactory.Alllivingthingscontainchemicalsthathelpthemsurvive.Soscientists’interestintraditionalmedicineisnotnew.Butithasbecomeanurgentconcern.Thisisbecausetheearth’’ssupplyofnaturalmedicinesmaybedroppingrapidly. WhichofthefollowingstatementsisNOTtrue?
TheFunctionofTomatoes Howdowelovetomatoes?Let’’scounttheways:welovetheminpastaonpizzainjuiceinsaladandsoupslicedonsandwichesstuffedwithtunaevendriedandbakedinbagelsbutmostofallwelovethemrightoffvine—riperedanddelicious. Whiletomatoloversdon’’tneedanexcuseforeatingthembythebushel蒲式耳nowthere’’sevenmorereasontosavorthesedeliciousfruits.Evidenceismountingthatpeoplewhoeattomatoeshaveasubstantiallylowerriskforcancer. Inathousand-personstudyofeatinghabitsandhealthHarvardMedicalSchoolresearchersfoundthatthosewhoatetomatoeseveryweekhadthelowestchanceofdyingformcancer. Recentlyastudyof48000Americanmenshoweda21to34percentlowerriskforprostatecancer前列腺癌amongthosewhoconsumedtomatoestomatosauceorpizzamorethantwiceaweek.AndinstudyofmenandwomeninItalyeatingsevenormoreservingofrawtomatoesaweekwaslinkedtoa30to60percentreductionindigestivetractandprostatecancersdependingonthetypeofcancer. Theprotectivequalitiesofthetomatoarethoughttocomefromlycopene番茄红素apotentantioxidant抗氧化的plantchemicalthatisabundantintomatoes.Lycopeneisresponsiblefortheredcoloroftomatoes;thedarkerredthetomatoisthemorelycopeneitcontains.Greenandyellowtomatoesdonotcontainlycopene. Lycopoeneisalsofoundinwatermelonandpinkgrapefruitbuttomatoesarethemostabundantsource.Cookingenhancesthelycopenemoreavailable.Thustomatosauceandpasteisevenabettersourceforlycopenethanfreshrawtomatoes.Lycopeneisfatsolubleandmustbeconsumedwithacertainamountoffattobeabsorbedbythebody.Tomatorecipesmustcontainamoderateamountofoiltoensurethatalongwithadelicioustastetreatyouwillalsobereceivingallthehealthbenefitstomatoeshavetooffer. Accordingtothepassageitisshowed______lowerriskforprostatecanceramongthosewhoconsumedtomatoesmorethanonceaday.
NewTechniquePromisesEarlierCancerDetection AnewtechniquecouldrevolutionizetheearlydetectionofcancergivingsufferersagreaterchanceofbeatingthediseaseAmericanscientistssaid.ResearchersattheMassachusettsInstituteofTechnologyhavedevisedanovelmethodof【51】changesinthenucleusofcellsintheearlieststagesofthedisease.Morethan85percentofallcancersoriginateintheepithelium上皮thatlinestheinternalsurfacesoforgans【52】thebody.Althoughthesearetreatable【53】theyarediagnosedinoneofthepreventablestagesearlybodydamagesarealmost【54】todetectsaidscientistFeld.Wepresentanewoptical-probe光学探子techniquebasedonlight-scatteringspectroscopy分光镜检查thatisable【55】detectprecancerousandearlycancerouscellsincell-richepitheliaheaddedinastatement. Thenewtechniquereliesonthefact【56】cellnucleichangeintheearlystagesofcancerandthedifferencesscatterlightinacharacteristicway.Untilnowthechangeswereonlydetectable【57】abiopsy活检wastakenthescientistssaid.Thenewtechnique【58】inthesciencejournalNaturecanbeusedinconjunctionwitharoutinecancerscreeningandsurveillancetechniquewhichusesanendoscope内窥镜—aflexibleopticalprobe【59】withcameraswhichisinsertedintoacavityinthebody—tocheck【60】cancers. Thescientistssaidthey【61】theirnewtechniqueinfourdifferentorgansduringroutineendoscopiccancerscreening.Thetipoftheopticalprobewasbroughtintocontactwiththetissuetobetestedandthescatteringoflightwasrecordedwithouttheneedforanytissuetobe【62】thescientistssaid.Ourresultsshowthatlight-scatteringspectroscopyhasthepotentialtodetectpre-cancerousbodydamagesandpreinvasivecancersthroughoutthebody.Thistechniqueshould【63】improvetheefficiencyofcancerscreeningandsurveillancethescientistssaid.Cancerisoneofthebiggest【64】inindustrializedcountries.【65】tofiguresfromtheWorldHealthOrganization10millionpeoplewerediagnosedwiththediseaseworldwidein1997andsixmilliondied.
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