简介:ToestablisharapididentificationmethodforcommonpathogenicbacteriaonthebasisofmolecularbiologyandtoconstructapreliminaryPolymeraseChainReaction-CapillaryElectrophoresis-RestrictionFragmentLengthPolymorphism(PCR-CE-RFLP)databaseofbacteriaisolatedfromclinicalspecimensfrequently,183strainscollectedfromclinicalsamplesbelongingto12generaand19specieswhosebiochemicalcharacterizationscorrespondedtothetypicaloneswereexamined.ThegenomicDNAswereamplifiedbytwopairsoffluorescencelabeledprimersaimingat16SrRNAgeneand16S-23SrRNAspacerregiongenerespectivelyatthesametime.PCRproductswerethendigestedbyrestrictionendonucleaseHaeⅢin-completelybeforetakingcapillaryelectrophoresis.TheresultswiththePCR-CE-RFLPpatternsof16SrRNAgeneswerejustalikewithinsomegenera,butwhenitcomesto16S-23SrRNAspacerregiongenes,eachbacteriumshowedauniquepattern,whichcanbedistinguishedfromeachothereasily.ItseemsthatPCR-CE-RFLPpatternsof16SrRNAgenecouldonlybeusedtoclassifythebacteriaintofamilylevel,whereasthedataof16S-23SrRNAspacerregiongenecouldbeutilizedtoidentifythewholemicroorganismsaspreciselyasthespecieslevel.Inspiteofthedataofthespacerregiongenealonecanbesufficientlytoverifythewholebacteria,weinsistthatthe16SrRNAgenecouldbeofsomeassistantincasethatthereshouldbelotsoffamiliesofbacteria,inwhichsomesimilarones,withthesameRFLPdataof16S-23SrRNAspacerregiongene,maycoexist.ThisstudyprovesthattheutilityofPCR-CE-RFLPisaconvenient,rapidmethodtoidentifypathogenicbacteria,andisalsoaquickdiagnosismeasureforapplicationtoclinicaluse.
简介:TherelationshipbetweenembBmutationofMycobacteriumtuberculosisandethambutol(EMB)resistanceoftheclinicalisolatesoftuberculouspatientsinChinawasinvestigatedbyreversedotblothybridization(RDBH)inadditiontoevaluatingtheclinicalvaluewithapplicationofPCR-RDBHtechniquetodetectEMBresistance.Inthepresentstudy,thegenotypesofthe258bpfragmentsofembBgenesfrom196clinicalisolatesofM.tuberculosiswereanalysedwithRDBHandDNAsequencing.Itwasdemonstratedthat60outof91phenotypicallyEMB-resistantisolates(65.9%)showed5typesofmissensemutationsatcodon306ofembBgene,resultinginthereplacementoftheMetresidueofthewildtypestrainwithVal,IleorLeuresidues.Inthesemutations,theGTPmutation(38/91,41.8%)andtheATAmutation(16/91,17.6%)werethemostencounteredgenotypes.TheembBmutationatcodon306couldalsobefoundin69isolatesofphenotypicallyEMB-sensitivebutresistanttootheranti-tuberculousdrugs,butnosuchgenemutationcouldbefoundin36strainsofdrug-sensitiveisolates.Meanwhile,theconcordancewiththeresultsofDNAsequencingforonewide-typeprobeand5probesforspecificmutationswas100%.ItwasconcludedthattheEMB-resistanceoccurringinmostM.tuberculosisisduetoappearanceofembBmutationatcodon306,andthePCR-RDBHassaywasprovedtobearapid,simpleandreliablemethodforthedetectionofgenemutations,whichmightbeagoodalternativeforthedrug-resistancescreening.
简介:【摘要】目的 探讨适应性统计迭代(adaptive statistical iterative reconstruction,ASIR)、滤波反投影(FBP)两种重建技术对胸部CT图像质量的影响。方法 80例患者均应用西门子64排CT行胸部CT平扫。分别用ASIR、FBP两种重建算法对原始数据进行重建,重建层厚1mm,层间距0.5mm。测量记录信噪比(SNR)、图像噪声、对比噪声比(CNR)。对肺窗和纵隔窗进行图像质量评价。对比分析两种不同重建算法的定性定量参数。结果 两组图像的噪声值分别是35.6±14.5,52.5±18.6,与FBP组比较,ASIR组噪声降低了31.4%,ASIR组的SNR和CNR明显高于FBP组(P<0.05)。且ASIR组肺窗及纵隔窗图像质量较FBP组高,差异有统计学意义(P<0.05)。结论 与FBP重建算法相比,ASIR可明显降低图像的噪声,提高图像质量。