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Acute,subchronic,andchronictoxicityofachemicalcompoundcanAcute,subchronic,andchronictoxicityofachemicalcompoundcanbeevaluatedbyfivebasic•••••Animaltestswithhigherorganisms(invivo)Testswithlowerorganisms(invivo)Testswithcellcultures(inComputercalculations(inEpidemiologicalHumanEpidemiologicalHumanexposuretoachemicalcompoundcan••Incidentalviaenvironment,occupation,orIntentional,forexample,withadrugorafoodEpidemiologicalStudyEpidemiologicalStudy•••••AnalyticresearchEpidemiological––health-relatedstatesor•••••Epidemiological––health-relatedstatesor••••••••GroupsofaffectedCauseofdeathResponsetoProvisionanduseofhealth–•••••–inspecified•••IdentifiableExamplesofspecificpopulationsPreciselydefinednumbersEpidemiologicalstudiescanbeclassifiedintofourCohortEpidemiologicalstudiescanbeclassifiedintofourCohortstudies（群体研究）duringwhichtheexposedindividualsareprospectivelyinvigilated••Clinicalstudiesofexposedindividualswhohaveanestablisheddiseasearecomparedwithcontrolsubjectsnothavingthis••IncidentalexposureCross-sectionalstudies（横向研究）wherethespreadofthediseaseintheexposedgroupisstudied••PopulationEcologicalstudies（生态研究）,wheretheincidenceofdiseaseinacertaingeographicareainwhichtheexposuretotoxicantishighlyprobableiscomparedwiththeincidenceinanotherareapositivelyfreeofthis••FoodtoxicologicalAnimalMostoftheAnimalMostoftheknowledgeconcerningthetoxicityofasubstanceisobtainedfromanimalstudies.Thisinformation•Fortheriskassessmentandsafetyevaluationofadrugbeforethehuman•Forestimationofno-observedadverseeffect(NOAEL)valuesoffoodadditivesbeforetakeinto•ForriskassessmentofvariouschemicalsusedinindustryandintheGeneralprinciples:toGeneralprinciples:tofollowprinciplesofcareand••guidelinesandlawsandgovernment•USDA,theAnimalWelfareTwobasicTwobasicaxiomsindesigninganimalTheadverseeffectofatoxicantcanin“principle”beextrapolatedfromanimalstohumansSamedosageinmg/kgbw(humansare10timessensitivethanThebodyareaandtheunitForcalculationofbodyarea,WhereKisaspecies-specificfactor(9forrat,10.6forhumans),wisthebodyweightofthelaboratoryanimalinkgToTominimizethenumberofnecessarylaboratoryItisnecessarytohave30000laboratoryanimalstodetectcancerwithanincidenceof0.01%Therefore,hightoxicantdosesandextrapolationtosmalldosesareusedforthehumanriskassessmentoftoxicantinsmallanimalEquivalentToxicDosesfor4Animal2EquivalentToxicDosesfor4Animal2laboratoryanimalsandlaboratoryanimalsandextrapolationtoManytoxicantsarecapableofcausingseriousharmtoanorganism,notproducinganyadverseeffectAnimalsvs.AnimalsaresensitivetoPlantsaresensitivetoAnimalsvs.AnimalsaresensitivetoPlantsaresensitivetoNervous//Bloodand//Cell/ThevariabilityofThevariabilityoftoxicresponsecanbecauseddifferencesinthefunctioningofthebiochemicalpathwayofsulfonamides磺胺类resemblep-aminobenzoicacid(对基苯甲酸theprecursoroffolicacid,soantagonizesynthesisoffolicacidinMostimportantdifferencesbetweenHumansandthewidelyusedlaboratoryanimalratAnatomical（解剖结构Fastmultiplication（快速倍增ShortMostimportantdifferencesbetweenHumansandthewidelyusedlaboratoryanimalratAnatomical（解剖结构Fastmultiplication（快速倍增ShortThecaseofAbsenceofthevomitingreflex（呕吐反射DifferentneedsforvitaminandmineralsindependenceofascorbicacidinfoodNocturnalwayoflife（夜间生活方式Controlled/humidityinthecaseoftestInterstraindifferencesingenesisofspontaneoustumorsLiving Genetic Multiparous（多产的 Formationofα2γ-globulinin（球蛋白Drydiet Shortgestation/lactation(孕/哺乳期短 Presenceofudder（乳腺的存在Body Absenceofgallbladder（胆囊ThestructureofThestructureofanimaltoxicologicaltests•ThebiochemicalpropertiesoftheparticularOnitssupposedendOn••ThelaboratoryanimalsThelaboratoryanimalswereselectedbased••ThetypeofOnthepreliminaryinformationaboutthetoxicityofthecompoundtobetestedOntheethicalandfinancial•Inthestartingphaseofananimaltest,theapproximatetoxicitylevelInthestartingphaseofananimaltest,theapproximatetoxicitylevelofthetoxicdoseofacompoundshouldbedetermined.Usuallyacute/subchronic(28-or96-days),chronic(lifelong)testvitrotestsareAccordingtotheirAccordingtotheirsource,thetestanimalscandividedintothree•AnimalsobtainedfromwildpopulationoropencoloniesAnimalsderivedfromclosedAnimalsstemmingfromcoloniesobtainedbyCaesareansectionorembryotransplantation••Organism-independentfactorsinfluencingcompoundOrganism-independentfactorsinfluencingcompoundtoxicityThefollowingmaterialsisusableforestimationhumantoxicityofaparticularcompoundinaparticularsituation:•••••••DependenceonspeciesGeneticvariabilitiesGenericvariabilities（类属差异）:DependenceonageDietaryconditionsHealthconditionsSimultaneouscontactwithseveralCellculturepreliminaryassessmentCellculturepreliminaryassessmentofits•••UnscheduledDNAsynthesisUnscheduledDNAsynthesis•DNA DNAUnscheduledDNAsynthesis•DNA DNAdistinctfromthesemi-conservativereplicationofDNAwhichisconfinedtotheS-phaseoftheeukaryoticcellcycle(G1,S,G2andMphases).Detectedbyanelevatedincorporationof[3H]-thymidineintotheDNAofculturedmammaliancellsduringtherepairofdamage.Thiscanbedetectedbyautoradiographyassociatedwithimageanalysis.BlockthecellcycleatG1phase,andinhibitthesemi-conservativebysomechemicals,suchashydroxyurea(羟基脲),thenexposethecellsto••[3H]-incorporatedduringUDSintothosecellsthatarenotsemi-replicating•replicationwithsemi-conservativeIfautoradiographyistomonitorthisprocess,S-phasecellswhicharesemi-•replicationwithsemi-conservativeIfautoradiographyistomonitorthisprocess,S-phasecellswhicharesemi-fromtheanalysisduetotheirheavylabellingThemeasureofradiolabelledthymidineincorporated• semi-replicationinthecellSalmonellaTyphimuriumstrainsmutatedinofhistidinesynthesisauxotrophic营养缺陷型)mutants,i.e.theyrequirehistidineforgrowth.Themethodteststhecapabilityofthetestedsubstanceincreatingmutationsthatresultinareversionbacktoa"prototrophic"state,sothatthecellscangrowonahistidine-freeAmesAmesGiemsaGiemsa••••SisterchromatidMitosisanaphase（有丝分裂后期T(darkblue)（溴脱氧尿嘧啶核苷(light4-5SCEsperchromosomepairpermitosisisnormal,while14-100SCEsisabnormalandpresentsadangertothe•Metaphasespreadofacelllineshowingaringchromosome(R)andseveralSCEs,someofwhichareindicatedbyarrows.ComputerQSAR(quantitativestructure-activityComputerQSAR(quantitativestructure-activityquantifyingvariouselectronic,geometric,orstericpropertiesofamoleculearecomputedandusedtodevelopaQSAR电性参数、立体参数、几何参数、BasedontoxicityBasedontoxicityAcutetoxicityChronictoxicityAcutetoxicityAcutetoxicityTheconventionalLD50testwasfinallycancelledendof2002.Thefollowingalternativeanimaltestsofacutetoxicityhavebeendeveloped:•••FixeddoseprocedureAcutetoxicclass(ATC)methodProposedin1984Proposedin1984bytheBritishToxicologySociety,itisamethodtoassessasubstance'sacuteoralToidentifyadosethatproducesclearsignsoftoxicitybutnomortality.Givenatoneofthefourfixed-doselevels(5,50,500,and2000mg/kg)tofivemaleandfivefemalerats.Ifmortalityoccurs,retestingatalowerdoselevelisnecessary(exceptiftheoriginaldoseis5mg/kg).Ifnosignsoftoxicityoccur,itisnecessarytoretestatahigherdoselevel.In1992,thistestwasproposedasanalternativetotheLD50testbyOECD.ProposedbytheGermanProposedbytheGermanFederalHealthAdoptedin1996asanofficialtestguidelineoftheOECDandtheEuropeanUnion6levels:<1mg/kg,1-50mg/kg,51-500mg/kg,5000mg/kg,5001-15000mg/kg,>150003animalsofeachsexforeachProbitmodel(maximumlikelihoodArchToxicol.1992;66(7):455-ALTEX.1999;16(3):129-Limittest:startatLimittes