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1.
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毒物代谢动力学  毒物代谢动力学 (toxicokinetics)是一门毒理学的分支科学,它应用药物代谢动力学的基本原理和方法,通过建立数学模型来定量的阐述外来化合物在机体内吸收、分布、生在体内随时间变化含量在不断改变的动态规律,计算出其各项基本参数。基本参数包括峰值浓度、消除速率常数、半衰期、曲线下面积、清除率和表观分布容积等。血液灌流  血液灌流 (hemoperfusion,HP)是临床常用的血液净化方法之一,它通过将患者的血液从体内引出经过体外循环,利用体外循环灌流器中吸附剂的吸附作用清除外源性和内源性毒物、药物以及代谢产物等…  相似文献   

2.
综述了近年来国内外工业毒物代谢动力学领域的最新研究成果,阐述了毒物代谢动力学数学模型在职业接触化学物的危险性评估方面的重要作用和实用价值,探讨了利用数学模型研究工业毒物代谢动力学目前存在的问题及今后的发展方向。  相似文献   

3.
目的探讨活性炭血液灌流(HPA)对急性重度敌敌畏中毒的代谢动力学的影响。方法通过静脉推注敌敌畏(100 mg/kg)染毒雄性比格犬,并随机分成治疗对照组(常规治疗)和HPA组(HPA+常规治疗),每组各5只。动态检测两组比格犬血浆中敌敌畏浓度,利用DAS2.1.1软件计算两组毒物代谢动力学参数。结果(1)静脉推注敌敌畏后,敌敌畏在比格犬体内分布与清除符合二室开放模型,Vd=(17.803±10.345)L/kg,t1/2=(6.260±3.078)h,清除率(C l)=(1.955±0.757)L/(h.kg);两组间毒物代谢动力学参数差异无统计学意义(P>0.05)。(2)HPA治疗期间,HPA组比治疗对照组的体内存留时间(MRT)、t1/2缩短,C l增大,两组间差异有统计学意义(P<0.05)。结论在急性重度敌敌畏中毒的早期应用HPA技术可短时间内降低血浆中毒物浓度,改变毒物代谢动力学参数,但对体内毒物负荷总量的清除作用尚不明显。 更多还原  相似文献   

4.
毒鼠强在家兔体内的代谢动力学研究   总被引:9,自引:0,他引:9  
目的 探讨毒鼠强在家兔体内的毒物代谢动力学特点及活性炭经口灌胃后对毒鼠强代谢动力学的影响。方法 代谢动力学研究分为静脉染毒组、经口灌胃染毒组和排泄组,每组 4只家兔,静脉染毒组、经口灌胃染毒组家兔染毒后从耳中央动脉定点采血,排泄组家兔在留置胆道和尿道插管后染毒,定时留取胆汁和尿液;活性炭对毒鼠强代谢动力学的影响研究分为对照组与活性炭组,每组 6只家兔,经口灌胃染毒后,活性炭组家兔给予活性炭悬浊液灌胃,对照组给予等量蒸馏水灌胃,从耳中央动脉定点采血。所有样品使用气相色谱氮磷检测器法定量测定,并用 3p87软件对数据进行代谢动力学分析。结果 毒鼠强在家兔体内的排泄速度缓慢,静脉染毒组的排泄半衰期为56 9h,总清除率为 24 .1ml·kg-1·h-1,经口染毒组的排泄半衰期为 262 .5h,总清除率为 15. 4ml·kg-1·h-1。毒鼠强主要从尿液排出,其排泄量是胆汁的 5倍以上。给予活性炭灌胃后,毒鼠强代谢动力学各项参数与对照组比较差异均有统计学意义,活性炭组的排泄半衰期相当于对照组的55%,总清除率则提高了 3倍以上,曲线下面积只有对照组的 30%。结论 毒鼠强是排泄速率缓慢的毒物,经尿液排泄的毒物量明显大于胆汁,经口给予活性炭灌胃可以加快其从体内排泄。  相似文献   

5.
苯酚与脱氧核糖核酸的相互作用   总被引:4,自引:1,他引:3  
宋远志 《中国公共卫生》2005,21(12):1516-1517
苯在人体内可代谢为苯酚、氢醌、苯醌等多种代谢产物.研究毒物代谢产物与DNA相互作用的方法有体内同位素前标记法、体外加合物的研究、体内加合物的研究等,这些方法多在生物体内或在体外细胞组织中进行,由于生物代谢的复杂性,单种毒物与DNA的相互作用的实验结果不明确,不能考察单种毒物对DNA损伤机制.因此,从分子水平讨论DNA与毒物的相互作用,可以更加准确地阐明DNA损伤机制,为认识致癌机制,有效治疗癌症提供依据.本文通过循环伏安法和荧光光谱法、紫外光谱法、量子化学方法研究苯酚与DNA的相互作用方式.现将结果报告如下.  相似文献   

6.
有关三硝基甲苯(TNT)在体内的毒代动力学及代谢产物的生物接触限值报道较少。一般认为对接触者进行生物监测是评价毒物多种途径进入人体的可靠指标[1]。目前国内处均在探索毒物在体内的接触阈限值,试图以此来代替某些毒物车间空气中最高容许浓度。为了解TNT作...  相似文献   

7.
药代动力学是从希腊词“Pharmako”(医药或毒物)和“Kinetikos”(转运)引伸而来,包括药物、杀虫剂、环境污染物、工业废物等外源性化合物在体内的吸收、分布、代谢和排泄的经时过程,药代动力学的原则可以应用到任何一种外环境非营养物在机体内动态量变规律的研究上。掌握这些化合物在体内位置、数量与时间的关系以及它们在体内持续  相似文献   

8.
毒物代谢动力学(tocxicokinetics)是一门毒理学的分支科学,它应用药物代谢动力学的基本原理和方法,通过建立数学模型来定量的阐述外来化合物在机体内吸收、分布、生物转化和排泄的过程,根据外来化合物本身或其代谢产物在体内随时间变化含量在不断改变的动态规律,计算出其各项基本参数。基本参数包括峰值浓度、消除速率常数、半衰期、曲线下面积、清除率和表观分布容积等。  相似文献   

9.
急性对硫磷中毒活性炭血液灌流的疗效研究   总被引:1,自引:0,他引:1       下载免费PDF全文
目的 探讨血液灌流(HP)对于急性有机磷农药中毒的治疗效果.方法 建立狗急性对硫磷中毒模型:将动物随机分成HP组(进行血液灌流)和对照组(未进行血液灌流).气相色谱法和速率比色法测定血浆对硫磷浓度、活性炭吸附对硫磷总量和血清丁酰胆碱酯酶活力.结果 (1)静脉染毒后,血浆中对硫磷浓度.时间变化曲线符合多室模型,动力学参数如下:t1/2=(15.33±12.95)h,Vd=(13.13±9.99)L/kg,CL=(0.86±0.44)L/(h.kg);(2)HP期间血浆对硫磷浓度下降较快,但此后对硫磷浓度逐渐升高,并于HP后2 h,两组血中对硫磷浓度无统计学差异(P>0.05);(3)活性炭共清除机体毒物负荷总量的(0.25±0.16)%;(4)HP后,丁酰胆碱酯酶活性逐渐升高,36 h达到峰值,此后下降;(5)HP组与对照组比较,昏迷时间[(30.33±6.03)h vs(29.17±5.97)h.P>0.05]差异无统计学意义.结论 活性炭血液灌流治疗急性对硫磷中毒作用有限.  相似文献   

10.
氯乙烯是一种可损害多器官的毒物,也是已知人类致癌物.其活性代谢中间产物具有强烈烷化作用,可在体内形成多种加合物.以氯乙烯的代谢和毒性机制为基础,研究了一系列其致机体损伤的指标,并试图寻找氯乙烯的生物标志物.本文就氯乙烯在体内的代谢转归及其活性中间产物、接触生物标志物、遗传学改变、血清癌蛋白和肝损伤指标等效应标志物以及基于其代谢酶基因多态性的易感生物标志物进行综述.  相似文献   

11.
Conclusion From the data presented in this paper, it is concluded that parathion does not accumulate to any appreciable extent in any of the organisms of this data to environmental situations is reasonable, as there has not been any indication of accumulation of organophosphate insecticides by upper food chain organisms such as fish. The chemical properties of parathion, such as the susceptibility to degradation by physical, chemical, or biological means to polar products, readily account for the low accumulation of parathion by the aquatic organisms of this ecosystem. It appears that the continued use of parathion for insect control will not result in the ubiquitous environmental contamination which has occurred with the use of chlorinated hydrocarbons, such as DDT.  相似文献   

12.
The feasibility of decontaminating soil at parathion spillage or disposal sites by inoculation with a highly acclimated culture of parathion-degrading bacteria was demonstrated underin situ field conditions. The acclimated culture (AC), capable of utilizing parathion as a sole carbon and energy source, was inoculated into Yolo silt loam soil in which parathion was applied at rates up to 5000 kg/ha. The AC was shown to be capable of completely degrading parathion in soil containing up to 1250 kg/ha of parathion within 35 days. A slower rate of parathion degradation by the AC was observed when the pesticide was applied as the commercial 46.5% emulsifiable concentrate than when applied as the 98% technical grade. The ability of the AC to degrade parathion deteriorated at application rates greater than 1250 kg/ha. The AC may have been adversely affected by the accumulation of the parathion hydrolytic products,p-nitrophenol and ionic diethyl thiophosphate, which were tentatively identified in soil samples.  相似文献   

13.
Summary This study determined the toxicity of parathion and methyl parathion to organochlorine compound-resistant and -susceptible populations of mosquitofish (Gambusia affinis). Mosquitofish can tolerate about 40 times more methyl parathion than parathion. The resistant population demonstrates a 1.3 fold greater tolerance of methyl parathion than the susceptible population, which may be a developing resistance. The resistant population also demonstrates an environmentally-induced tolerance to parathion (1.6 fold) in the spring but no overall tolerance to parathion in the fall when compared to the susceptible population.This study was supported by NIH grant 5 ROI 00412 and NSF Graduate Traineeship grants GZ-1629-1970-71 and Gz-2036-1971-72.  相似文献   

14.
Factors affecting the stability of parathion in the aquatic environment were studied, with emphasis on pH. In 24-hr toxicity tests, using the midgeChironomus riparius, parathion was significantly more toxic at pH 6 than at pHs 4 and 8. While the data from toxicity tests suggested that pH may be important in determining the environmental fate of parathion, pH was found to be insignificant in controlling levels of parathion in water and organisms of aquatic microcosms adjusted to pHs 4, 6, and 8. After 7 days, parathion accounted for 29.7, 28.7, and 36.6% of total radioactivity in the water of microcosms held at pHs 4, 6, and 8, respectively. In abiotic water, however, no parathion breakdown was observed in 40 days at any of the three pH levels. These data demonstrate the importance of biotic factors, particularly microorganisms, in degrading parathion. Microorganisms which metabolize parathion in the microcosms were not adversely affected by changes in pH.  相似文献   

15.
A study comparing the leaf residue decay of parathion wettable powder (8 lbs per acre) on oranges was carried out on neighboring plots in Arizona beginning in October, 1975, and February, 1976. While identical amounts of parathion were present immediately after spraying and the half-life of parathion was the same in both months, there was, on the average, more parathion residue during February. Graphs of parathion and paraoxon levels over time differed between months (in excess of sampling variability). This most likely was due to the daily influences of climatological variables which were obviously different in October and February.  相似文献   

16.
Summary A study comparing the leaf residue decay of parathion wettable powder (8 lbs per acre) on oranges was carried out on neighboring plots in Arizona beginning in October, 1975, and February, 1976. While identical amounts of parathion were present immediately after spraying and the half-life of parathion was the same in both months, there was, on the average, more parathion residue during February. Graphs of parathion and paraoxon levels over time differed between months (in excess of sampling variability). This most likely was due to the daily influences of climatological variables which were obviously different in October and February.  相似文献   

17.
Staff of the California Department of Health Services investigated the death of a parathion applicator in California that was thought to be pesticide-related. A crew of eleven workers (including six sprayers, three mixer/loaders, one mixer/sprayer and one foreman) had been applying 0.125% parathion spray to almond orchards for approximately three weeks. On the day of the fatality, a sprayer rapidly developed symptoms of salivation, sweating, and convulsions after a half-day of work. Despite aggressive medical treatment, the worker died within one hour of his initial symptoms. Significant laboratory results for the decreased case included: parathion residue on the inner and outer garments worn by the worker, parathion in the post-mortem gastric contents, and elevated urinary metabolites consistent with acute parathion intoxication. Interviews with the work crew revealed that three of the 10 workers had complaints of headaches, vomiting, and/or sore throat; yet, subsequent plasma and red cell cholinesterase tests of the co-workers did not show any significant depressions in comparison with pre-season baseline values. This worker death is consistent with prior reports of parathion-related sprayer/applicator intoxications and is the first worker-related parathion death in California since 1972. Substitution of pesticides with less toxic active ingredients or the elimination of parathion is recommended.  相似文献   

18.
Male rats were fed diets containing 0, 1, or 5 ppm parathionad libitum for 28 days. Three other groups of rats were fed diets containing 0, 2, or 10 ppm parathion for 28 days but were fed only 50% of the food intake of the correspondingad libitum groups. Effects on plasma cholinesterase activity and plasma and liver carboxylesterase activities were observed in the 5 ppm and 10 ppm parathion groups. Food restriction increased the inhibition elicited by parathion with each of these parameters. No significant inhibition of brain cholinesterase by parathion alone or with food restriction was observed. Lesions of the pancreas were noted in animals receiving 10 ppm of parathion and subjected to 50% normal food intake.  相似文献   

19.
Persistence curves obtained for parathion in six California soils are partially dependent on soil type. The possibility that long-term, low-level parathion soil residues can exist is confirmed. Each soil was fortified at 20 ppm, kept in an enameled tray, and maintained at 30°C with a soil moisture level of approximately 40 percent of saturation. The parathion residue in Laveen loamy sand drops rapidly to about 0.2 ppm in 30 days. In Mocho silt loam, Linne clay, and Madera sandy loam, it drops to between one and two ppm in 30 days and gradually decreases to about 0.2 ppm in 130 days. The rapid parathion residue decline is attributed to microbial degradation. In Windy loam, the residue after eight months remains above three ppm. In two experiments differing slightly in soil moisture, the residue in Santa Lucia silt loam is about 1.5 ppm after eight months in one experiment and about 0.5 ppm after six months in the other. The latter two soil types give linear semi-logarithmic persistence curves, suggestive of degradation by hydrolysis.Aminoparathion, above the detectable level of one ppm, is not found in Madera sandy loam after fortification with parathion at 200 ppm. However, a sharp decline of the parathion residue after ten days suggests microbial degradation. Three ppm aminoparathion were recovered after seven days when Madera sandy loam was fortified at 20 ppm with parathion and submerged under water. In contrast, the degradation of parathion remaining in Windy loam (3.2 ppm) and Santa Lucia silt loam (2.2 ppm) 7.7 months after fortification is not greatly accelerated when flooded with water.  相似文献   

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