资源描述：
《最新影响毒物在生物体内所表现的毒性作用之因素PPT课件.ppt》由会员上传分享，免费在线阅读，更多相关内容在教育资源-天天文库。
1、影响毒物在生物体内所表现的毒性作用之因素Dose-ResponseRelationship:Asthedoseofatoxicantincreases, sodoestheresponse.23401DOSERESPONSE0-1NOAEL2-3LinearRange4MaximumResponseDOSEDETERMINESTHEBIOLOGICALRESPONSEExposure:DurationAcute<24hrusually1exposureSubacute1monthrepeateddosesSubchronic1-3morepeated
2、dosesChronic>3morepeateddosesOvertime,theamountofchemicalinthebodycanbuildup,itcanredistribute,oritcanoverwhelmrepairandremovalmechanisms暴露途徑a.呼吸道:氣體、分子小、脂溶性物質可由肺泡吸收，經由擴散(CO、HCN)或吞噬作用(石綿、鉛)b.消化道:毒物隨食物飲水進入腸胃，重金屬需和必需金屬(鈣、鐵)競爭載體，不易吸收。c.皮膚的表皮不易穿透，角質層阻擋水溶性物質之吸收，脂溶性物質則易穿透，角質層依身體之部位不同
3、有差異，影響吸收速率。DermalExposureVariablesAreaRate*forehead4.2forearm1.0abdomen2.1palm1.3scrotum11.8balloffoot1.8mjweaver,1997*Absorptionratecomparedtoforearm,whichis1.0毒物的化學性質和活性Thetoxicityofmercuryvapordiffersgreatlyfrommethylmercury.2.Anotherexampleischromium. Cr3+isrelativelynontox
4、icwhereasCr6+causesskinornasalcorrosionandlungcancer.3.Theinnatechemicalactivityofsubstancesalsovariesgreatly.Somecanquicklydamagecellscausingimmediatecelldeath.Othersslowlyinterfereonlywithacell'sfunctionEx.hydrogencyanidebindstocytochromeoxidaseresultingincellularhypoxiaandra
5、piddeath,nicotinebindstocholinergicreceptorsintheCNSalteringnerveconductionandinducinggradualonsetofparalysisDatafromarticleinScientificAmerican,February1986.OrganismLD50(micrograms/kg)Guineapig(male)0.6Guineapig(female)2.1Rabbit115Monkey(female)<70Rat(male)22Rat(female)45-500M
6、ouse(male)<150Dog(male)30-300Dog(female)>100Frog1,000Hamster1,157世紀之毒"Dioxin"(TCDD=2,3,7,8-tetrachlorodibenzo-p-dioxin)種、品系間之差異Rate:cat>rat>rabbitOxalate'stoxicityresultsfromitscomplexingofmagnesiumandcalciumions,makingthemunavailable.Oxalate解毒酵素活性不同Dogs,CatsRats,miceAnilinep-a
7、minophenolo-aminophenol對毒物有不同的解毒機制Malaoxonisapotentcholinesteraseinhibitor對毒物有不同的解毒機制Malathione2.生物轉化(biotransformation)有差異2-naphthylamine→2naphthylhydroxyamine導致dogandhuman膀胱癌acetylaminofluorene(AAF)僅天竺鼠不hydroxylation→不致癌3.對毒物的吸收、分佈與排泄有差異4.生理功能有差異squillasarodenticide,ratscanno
8、tvomit5.解剖上的差異BHA(butylatedhydroxyanisole)和BHT(butylat
