简介:DNAisthegeneticmaterialofvariousorganisms.ExtracellularDNAadsorbedorboundonsurface-activeparticlesinsoilshasbeenshowntopersistforlongperiodsagainstnucleasesdegradationandstillretaintheabilitytotransformcompetentcells.ThispaperreviewssomerecentadvancesonthebindingandtransformationofextracellularDNAinsoils,whichisfundamentaltounderstandingthenatureofthesoil,regulatingbiodiversity,andassessingtheriskofreleasinggeneticallyengineeredmicroorganisms(GEMs)aswellasbeinghelpfulfordevelopmentofthegeneticevolutionaltheoryofbacteria.Severalinfluencingfactors,suchassoilpH,ionicstrength,soilsurfaceproperties,andcharacteristicsoftheDNApolymer,arediscussed.Todate,theunderstandingofthetypeofmolecularbindingsitesandtheconformationofadsorbedandboundDNAtosoilparticlesisstillinitsinfancy.
简介:Colorectalcarcinoma(CRC)isacommoncauseofmorbidityandmortalityworldwide.TwopathogenicpathwaysareinvolvedinthedevelopmentofadenomatoCRC.ThefirstpathwayinvolvesAPC/β-catenincharacterizedbychromosomalinstabilityresultingintheaccumulationofmutations.ThesecondpathwayischaracterizedbylesionsinDNAmismatchrepairgenes.AberrantDNAmethylationinselectedgenepromotershasemergedasanewepigeneticpathwayinCRCdevelopment.CRCscreeningisthemostefficientstrategytoreducedeath.SpecificDNAmethylationeventsoccurinmultistepcarcinogenesis.EpigeneticgenesilencingisacausativefactorofCRCdevelopment.DNAmethylationshavebeenextensivelyexaminedinstoolfromCRCandprecursorlesions.ManymethylatedgeneshavebeendescribedinCRCandadenoma,althoughnodefiniteDNAmethylationbiomarkerspanelhasbeenestablished.MultipleDNAmethylationbiomarkers,includingsecretedfrizzled-relatedprotein2,secretedfrizzled-relatedprotein1,tissuefactorpathwayinhibitor2,vimentin,andmethylguanineDNAmethyltransferase,havebeenfurtherinvestigated,andobservationshaverevealedthatDNAmethylationbiomarkersexhibitwithhighsensitivityandspecificity.ThesemarkersmayalsobeusedtodiagnoseCRCandadenomainearlystages.Realtimepolymerasechainreaction(qPCR)issensitive,scalable,specific,reliable,timesaving,andcosteffective.Stoolexfoliatedmarkersprovideadvantages,includingsensitivityandspecificity.AstoolqPCRmethylationtestmayalsobeanenhancedtoolforCRCandadenomascreening.
简介:摘要目的探讨心电图J波现象与胸部肿瘤接触心脏的相关性。方法回顾上海市胸科医院自2016年8月至2019年12月诊断纵隔肿瘤、食管肿瘤及肺部肿瘤的患者共277例,分为左肺肿瘤组、右肺肿瘤组和纵隔窗肿瘤组。观察各组病例12导联心电图与胸部CT影像,分析心电图J波现象与胸部肿瘤接触心脏的相关性。结果在所有的277例样本中,J波共107例(107/277,38.6%)。J波与胸部肿瘤接触心脏有显著相关性(P<0.000 1,χ2=97.48),对预测后者的敏感性和特异性分别为71.7%和86.6%。其中,纵隔窗肿瘤组J波预测肿瘤接触心脏的敏感性(81.3%)和右肺肿瘤组J波预测肿瘤接触心脏的特异性(91.9%)最高。结论心电图J波与胸部肿瘤接触心脏有密切关联,同时对预测后者有较高的敏感性和特异性。