抗凝和溶栓英文版ppt课件.ppt

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1、AnticoagulantsandThrombolyticsS.RamakrishnanObjectivesTolearnhowBloodClotsareformed.Howthebloodclotsarebrokendown?Whatdrugscanbeusedtoregulateclotting?HowtorectifyclottingdeficienciesBloodclots-ThrombusThrombusdislodgefromarteriesandveinsandbecomeanembolus.Venousembolicanblocka

2、rteriolesinthelungandpulmonarycirculationThromboembolismClassesofDrugsPreventcoagulationDissolveclotsPreventbleedingandhemorrhage-HemostaticOvercomeclottingdeficiencies(replacementtherapies)BloodClottingVascularPhasePlateletPhaseCoagulationPhaseFibrinolyticPhaseVascularPhaseVas

3、oconstrictionExposuretotissuesactivateTissuefactorandinitiatecoagulationTissueFactorPlateletphaseNon-nucleated-arisefrommagakaryocytesbloodvesselwall(endothelialcells)preventplateletadhesionandaggregationplateletscontainreceptorsforfibrinogenandvonWillebrandfactoraftervesselinj

4、uryPlateletsadhereandaggregate.Releasepermeabilityincreasingfactors(e.g.vascularpermeabilityfactor,VPF)LoosetheirmembraneandformaviscousplugPlateletsandThromboemolismArteries:WhiteThrombusPlateletsadhereReleaseADPMoreadhesion/aggregationReducedbloodflow(stasis)FibrinclotVeinslo

5、wpressure:RedthrombusisformedEspeciallyinvalvepocketsContainsalongtailoffibrinCandetachandformemboliCoagulationPhaseTwomajorpathwaysIntrinsicpathwayExtrinsicpathwayBothconvergeatacommonpoint13solublefactorsareinvolvedinclottingBiosynthesisofthesefactorsaredependentonVitaminK1an

6、dK2MostofthesefactorsareproteasesNormallyinactiveandsequentiallyactivatedHereditarylackofclottingfactorsleadtohemophilia-AIntrinsicPathwayAllclottingfactorsarewithinthebloodvesselsClottingslowerActivatedpartialthromboplastintest(aPTT)ExtrinsicPathwayInitiatingfactorisoutsidethe

7、bloodvessels-tissuefactorClotting-faster-inSecondsProthrombintest(PT)Prothrombintime(PT)TissueThromboplastinfactorIIIMixwithphospholipidextractAddcalciumandbloodsampleDetermineclottingtimeGenerally12-14secondsUsedtodetectdefectsinextrinsicpathwayActivatedpartialthromboplastinti

8、me(APTT)Bloodsample+EDTAorCitrateNoclot(recalcificatio