VOA美国英语听力原稿.docx
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VOA美国英语听力原稿.docx
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VOA美国英语听力原稿
Study:
EradicatingCancer-CausingInfectionFeasible
ArtChimes|St.Louis,Missouri
July22,2011
Anewstudyfindsitmaybepossibletoeradicateaninfectionresponsibleforanoften-fatalcancer.
Theresearchalsoillustratesthecomplexitiesofthatapproach,especiallywhendifferenttreatmentsseemtoworkdifferentlyindifferentpartsoftheworld.
H.pyloriisanextremelycommonbacteria.Worldwide,abouthalfofushaveitinourgut.Mostofthetime,itdoesn'tbotherus.Butsometimesitcausesulcers,andH.pyloriisimplicatedinstomachcancer,thesecond-deadliestcancerworldwide.
Athree-drugtreatmentspreadoutovertwoweekshadbeenconsideredthepreferredtherapy.However,recentstudiesinEurope,Asia,andNorthAmericahavefoundthatafour-drugtreatmentgivenoverfiveto10dayswasmoreeffective.
Butthat'snotthecase,accordingtoanewstudy,forpatientsinLatinAmerica.
"Andwefoundthatthethree-drugregimen-somewhattomysurprise-actuallydidbetterthanthefour-drugregimen,"saidRobertGreenbergoftheFredHutchinsonCancerResearchCenterinSeattle,Washington.
Greenbergandhiscolleaguesrandomlyassignedabout1,500participantstodifferenttreatments.Theyfoundthatthefour-drugregimen-whichworkedsowellelsewhere-waslesseffectivethanthestandardtripletherapy.
Thestudywasconductedatsevenlocationsinsixcountries-Mexico,Nicaragua,Honduras,CostaRica,Colombia,andChile.
InaresearchpaperpublishedinTheLancet,GreenbergandhiscolleaguesexplainthattheresponsestothedifferentdrugcombinationsmightbeexplainedbyregionalvariationsinresistancethatH.pylorihasdevelopedtothespecificantibioticsandothermedicinesineachcombinationregimen.
Morethan87percentofthoseinthethree-druggroupwhotooktheirmedicinewerecuredoftheirinfection,asuccessratethatsuggeststhepossibilityoferadicatingH.pylori.ButresearcherGreenbergsaysit'snotasimpledecision.
"Ithink,althoughwewerepositiveinsayingwethinkit'sfeasibletoeradicate[H.pylori],weourselvesareundecidedastowhetherandhowaneradicationprogramshouldbeimplemented."
BecauseH.pyloriismorecommonindevelopingcountries,eradicationmightmakemoresenseinthoseareas,althoughGreenbergandhiscolleaguestakenopositiononwhetheritshouldbedone.
InacommentarypublishedwithGreenberg'spaper,atrioofBrazilianexpertsargueagainstmasseradicationforseveralreasons,includingthefearthatthewidespreaduseofantibioticscouldpromptdrug-resistantmutationsnotonlyofH.pyloributofotherpathogens,too.
StudiesShowExerciseReducesDementiaRisk
ArtChimes|St.Louis,Missouri
July22,2011
Evidencecontinuestomountthatphysicalexercisereducesaperson'sriskofdementia.
Insomeofthelatestresearch,scientistsmeasureactualphysicalactivity,ratherthanrelyonpeople'simperfectmemories.
Mostresearchersstudyingphysicalactivityanddementiarelyonself-reporting.Sothey'llaskpeopleinastudyaboutwhatexercisethey'vehadinthepastweek,forexample.
Butthereareproblemswithself-reporting.LauraMiddletonoftheSunnybrookResearchInstituteandtheUniversityofWaterlooinCanadasaysforonething,peoplejustdon'trememberwhatthey'vedone.Also,peopletendtoreportcertaintypesofactivitiesmorethanothers.
"[Self-reporting]doesaverygoodjobofcapturingjoggingorbikingortennis,butdoesarelativelypoorjobofcapturinglow-intensityactivitylikewalkingordailychores,whichmayalsobeimportanttotheriskofcognitiveimpairment."
Togetaroundthatproblem,Middletonmeasuredphysicalactivitywithanestablishedtechniquethatusesdoublylabeledwater,madefromisotopevariantsofhydrogenandoxygen.Participantsinthefive-yearstudydrankasmallamountofthisspecialwater,andbymeasuringtheisotopevariantsintheirurine,theirenergyexpenditurecanbecalculated.
"Whatwefoundwasastrongrelationshipbetweenactivityenergyexpenditureandtheriskofincidentcognitiveimpairment,shesays,"withthoseofhigheractivityenergyexpenditurehad90percentreducedriskofincidentcognitiveimpairmentoverthefollow-upperiodcomparedtothosewithverylowenergyactivityexpenditure."
LauraMiddletonandhercolleaguesdescribetheirfindingsonlineintheArchivesofInternalMedicine,publishedbytheAmericanMedicalAssociation.
Inthesameissue,anotherpaper-thisonefromFrenchresearchersledbyMarie-No?
lVercambreoftheFoundationofPublicHealthinParis-studiedtheexercise-dementialinkinalargegroupofwomenwithcardiacriskfactorssuchasobesityordiabetes.Inthisstudy,thewomenwhogottheequivalentofabrisk,half-hourwalkeverydayhadalowerriskofcognitiveimpairment.
Dr.EricLarsonoftheGroupHealthResearchInstituteinSeattle,Washington,saysthestudiesaddtotheevidencethatphysicalactivitycanreducetheriskofcognitivedecline.
"It'snotobvioustopeoplethatexercisewouldmakeyourbrainhealthier,"hesays."Andaseachstudydoesmoredetailedanalysesofspecialgroupsoradifferentwayofmakingthemeasurements,itjustmakesthescientificbasisforthisrelationshipalotmoreconvincing."
Larsonwritesthat,withaccumulatingevidenceofthelink,researchshouldnowfocusonhowbesttoencouragepeopletobeactive,especiallyinlaterlife.
AIDSDrugsOfferHopeofNormalLifespaninAfrica
JoeDeCapua|Washington
July18,2011
Overthelast30yearslifeexpectancyratesinAfricaplummeted,asHIV/AIDSclaimedmillionsoflives.Butanewstudysaysantiretroviraldrugtreatmentcandramaticallyreversethattrend.
ProfessorJeanNachegaco-authoredthestudyofsome20,000patientsinUganda.Hesaid,"TheoverallkeyfindingofourstudyisthatthepatientinAfricareceivingantiretroviraltherapyforHIVcanexpecttoliveanearnormallifespan."
ThefindingswerereleasedattheInternationalAIDSSocietyConferenceonHIVPathogenesis,TreatmentandPreventioninRome–andpublishedintheAnnalsofInternalMedicine.
Lostyears
BeforetheHIV/AIDSepidemic,expectedlifespansinmanyAfricancountrieshadrisensharply.Nachega,whoisaprofessorofmedicineatSouthAfrica'sStellenboschUniversityandascientistattheJohnsHopkinsBloombergSchoolofPublicHealth,witnessedthechangecausedbythedisease,cutting15,20ormoreyearsfromlifeexpectancy.
"Allwhatwe'vebeenabletogaininthepastwiththeaccesstocleanwater,expandedimmunizationprogramsweretotallyreversedwiththeHIV/AIDSepidemicinAfrica.Sonowweareseeingsomegoodnewsthatinvestinginantiretroviralprograms,thoseinvestmentsarenowpayingoff,"hesaid.
HecreditsPEPFAR,thePresident'sEmergencyPlanforAIDSRelief,andtheGlobalFundtoFightAIDS,TuberculosisandMalaria.
Genderdifferences
However,whiletheoverallfindingsarepositive,theydoshowadifferencebetweenmenandwomen.Womenarelivinglonger.Onereasonisthatmenwaitlongerbeforereceivingtreatment.
"Menjustingeneralhavealesshealth-seekingbehaviorascomparedtofemales.Menspendmoretimelookingforajobandspendingmoretimeawayfromtheirfamilytotrytofindawaytosurvive,Ithinkmaybeoneofthereasons.Thesecondreasonisobviouslytheissueaboutstigma,whichisstillquiteaffectingthemajorityofthepeopleinthecommunity,"hesaid.
WomenmayhaveagreateropportunitytolearntheirHIVstatusandreceivetreatmentthroughpre-natalcareprograms.Hesayshealthofficialsneedto"thinkhard"abouthowtoovercomethe"genderimbalance"intreatment.
Nachegasupportsthestrategyofusingtreatmentasprevention.
"Weshouldnolongerseetreatmentandpreventiontotallyseparately.Treatment,byitself,isalsopartofprevention.Becausebytreatingpeople,andhopefullytreatingpeopleearlier,theyarelesslikelytotransmitthevirustotheirsexualpartner,"hesaid.
StudiesalsoshowthatgivinguninfectedpeopleantiretroviralscanhelpprotectthemfromHIVduringsexwiththeirinfectedpartners.It'scalledpreexposureprophylaxis(PrEP).
Nachegasayswiththepreventiontoolsnowavailable,greatprogresscanbemadeagainsttheepidemic.ButhesaysthemagicbulletofaneffectiveAIDSvaccineremainselusive.
FunintheSunandSeaatMartha'sVineyardandNantucket
MARIORITTER:
WelcometoTHISISAMERICAinVOASpecialEnglish.I'mMarioRitter.ManyAmericanstaketheirsummervacationsinAugust.PresidentObamaandhisfamilyareamongthem.ThispastweekendthefirstfamilyvisitedtheFloridaGulfcoast.ThepresidentwantstosupporttourismintheareaaftertheBPoilspill.
OnThursday,thefirstfamilywillbeginaten-dayvacationonMartha'sVineyard,wheretheyspentpartoflastsummer.
PresidentObamastopsatastorewhileonvacationonMartha'sVineyardinAugust2009
TodaywetellaboutMartha'sVineyardandNantucket,twoislandsoffthecoastofMassachusettsthatarepopularplacesforsummervacations.
Bothislandsareknownfortheirsailingandsunsetsandfunthingstodo.Martha'sVineyardisalsoknownforitstallcliffsoverlookingtheAtlanticOcean.Theislandisaboutthirteenkilometersoffthecoastandislessthantwohundredsixtysquarekilometers.
HomesdesignedlikethoseofearliertimeslinethestreetsofEdgartown,OakBluffsandVineyardHaven.ThesearethemajortownsonMartha'sVineyard.
Formostoftheyear,thepopulationofMartha'sVineyardisaboutfifteenthousand.Duringthesummer,morethanonehundredthousandpeoplecrowdtheisland.InadditiontotheObamas,youmightseesomeHollywoodstarsandotherrichandfamouspeople.
Some
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