Bioavailability of dioxin in soil from a 2,4,5-T manufacturing site

Dioxin (2,3,7,8-tetrachlorodibenzo-p-dioxin, TCDD) is a highly toxic contaminant produced in the manufacture of phenoxy herbicides. Despite its high TCDD content, soil from a contaminated area associated with a 2,4,5-trichlorophenoxyacetic acid (2,4,5-T) manufacturing site in Newark, New Jersey, did not induce acute toxicity when administered to guinea pigs (the most sensitive species) by gavage. Analysis of liver samples demonstrated low bioavailability of TCDD from this soil. A comparative analysis of soils showed that Soxhlet extraction was necessary for the determination of TCDD on Newark soil, whereas solvent extraction was sufficient for soil from Times Beach, Missouri. The difference in the bioavailability of TCDD from these soils is correlated with TCDD extractability and may be related to the different compositions of the soils.     

Teratogenic effect of 5-hydroxytryptamine in mice

The subcutaneous injection of a single dose of 5-hydroxytryptamine into pregnant mice produced a large number of fetal abnormalities, mostly of the eyes, limbs, and tail; the skull and central nervous system were also sometimes affected. These effects could result from the action of the drug on placental function and blood supply.     

Teratogenic effects of meclizine hydrochloride on the rat

Congenital malformations were induced in the offspring of pregnant Sprague-Dawley rats by the admninistration of relatively large doses of meclizine hydrochloride (Bonine). The critical period of gestation for administration was from the 12th to 15th day. Anomalies were produced in the tongue, palatal closure, mouth, lower jaw, vertebrae and limbs.     

国产沙拉沙星的体内致突变性和致畸性研究

沙拉沙星 (Ｓａｒａｆｌｏｘａｃｉｎ)是新型氟喹诺酮类抗菌药物 ,1 995年首次在美国上市 ,是ＦＤＡ批准可用于食品动物的专用品种。其抗菌谱广、对革兰氏阳性菌、阴性菌均有高度的抗菌活性 ,在组织中的残留期短 ,是防治家禽大肠杆菌病、沙门氏菌病、霉形体病及霉形体与细菌混合感染的有效药物。为保证国产沙拉沙星的安全应用 ,我们按农业部有关规定对其进行了毒理学评价 ,为临床安全用药提供科学依据。1　材料与方法1 .1　药品与试剂沙拉沙星原粉 :含量 98.5 % ,批号 970 31 5 ;沙拉沙星口服液 ,浓度 1 % ,批号 970 31 5 ,均由洛阳惠中兽药…     

氯化镉对玉米根尖细胞的致畸效应

以不同浓度的氯化镉为诱变剂,对玉米根尖细胞进行致畸试验,测定不同处理时间玉米根尖细胞的微核率、有丝分裂指数和染色体畸变率.结果表明:氯化镉能诱发较高频率的微核率;处理6、12、24 h时,氯化镉质量浓度为0～10.00 mg/L时微核率随氯化镉质量浓度增加而上升,氯化镉质量浓度大于10.00～40.00 mg/L时微核率随氯化镉质量浓度增加而下降;有丝分裂指数随氯化镉质量浓度上升而下降,随处理时间的延长而升高;氯化镉还能诱导玉米根尖细胞产生较高频率的染色体畸变.     

Teratogenic effects of a chelating agent and their prevention by zinc

Ingestion of a chelating agent (ethylenediaminetetraacetic acid) by female rats during pregnancy impaired reproduction and resulted in congenitally malformed young. When ethylenediaminetetraacetic acid was fed from days 6 to 21 of gestation, all of the full-term young had gross congenital malformations. These effects were prevented by simultaneous supplementation with 1000 parts per million of dietary zinc.     

氯化钠对豌豆根尖细胞的致畸效应

以不同浓度的氯化钠为诱变剂,运用根尖细胞微核检测技术和染色体畸变实验方法,测定了豌豆根尖细胞的有丝分裂指数、微核率和染色体畸变率。结果表明：氯化钠能降低豌豆根尖细胞的有丝分裂指数,诱发较高频率的微核率和染色体畸变。浓度为0．05～0．25mol／L时,随着氯化钠浓度的增加,有丝分裂指数降低,而微核率、染色体畸变率均升高。即氯化钠对豌豆根尖细胞具有明显的致畸效应。     

斑马鱼胚胎经丙草胺暴露后对其仔鱼致畸效应的研究

为探讨斑马鱼胚胎暴露于丙草胺后对斑马鱼仔鱼的致畸效应和致畸机理,研究了斑马鱼胚胎暴露于0.50、1.00、1.50 mg·L~(-1)丙草胺染毒液120 h后仔鱼的畸形表型及比率,并通过检测与畸形器官发育相关的基因表达探讨致畸机理。结果发现,丙草胺暴露后诱导斑马鱼仔鱼出现心包囊肿、躯干弯曲、游囊关闭等畸形表型,随着暴露浓度的增加,各畸形症状比例增大。1.00、1.50 mg·L~(-1)暴露组仔鱼心包囊肿率分别为15.56%(P0.05)、25.56%(P0.01),脊柱弯曲率分别为27.78%(P0.01)、35.56%(P0.01);0.50、1.00、1.50 mg·L~(-1)暴露组仔鱼游囊关闭率分别为20%(P0.05)、37.78%(P0.01)和60%(P0.01)。丙草胺显著降低了心脏发育相关基因Tbx2[1.00 mg·L~(-1)(P0.01)、1.50 mg·L~(-1)(P0.05)],骨骼发育相关基因BMP-2[1.50 mg·L~(-1)(P0.05)]、BMP-4[1.00 mg·L~(-1)(P0.01)、1.50 mg·L~(-1)(P0.01)],游囊发育相关基因shha[1.50 mg·L~(-1)(P0.05)]、ihha[1.00 mg·L~(-1)(P0.05)、1.50 mg·L~(-1)(P0.05)]的表达水平。研究表明,丙草胺通过影响心脏、骨骼和游囊相关基因的表达引起斑马鱼仔鱼的以上器官发育异常。     

Combustion of Several 2,4,5-Trichlorophenoxy Compounds: Formation of 2,3,7,8-Tetrachlorodibenzo-p-dioxin

Grass and paper coated with several compounds containing the 2,4,5-trichlorophenoxy moiety have been subjected to combustion. By using compounds that had been purified to achieve low background amounts of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) together with an efficient cleanup and analysis of the residue, it was possible to detect as little as 0.001 microgram of TCDD in the combustion products of 0.5 gram of the 2,4,5-trichlorophenoxy material. Small self-supported fires converted about 10(-6) of the 2,4,5-trichlorophenoxy material to TCDD.     

米邦塔仙人掌粉对大鼠胚胎致畸作用的实验研究

为了了解仙人掌粉对SD大鼠胚胎致畸作用的影响。将大鼠雌雄1:1交配,发现阴栓作为妊娠“零”天,检出的“孕鼠”随机分到阴、阳性组及高、中、低剂量组,每组15只,称重和编号。于妊娠7～16d灌胃染毒,20d处死,分析胚胎发育指标与胎仔发育指标,检查有无外观和骨骼畸形。结果表明20d孕鼠体重增长阳性组与阴性组、剂量组相比有显著差异(P<0.05);各组着床总数无显著差异(P>0.05);活胎仔数、吸收胎数、死胎数、仔重、体长及尾长,阳性组与阴性组、剂量组相比有显著差异(P<0.05);剂量组与阴性组相比无显著差异(P>0.05);胚胎外形畸形率剂量组与阴性组之间无显著差异(P>0.05)。在本实验剂量和条件下仙人掌粉未见有母体毒性、胚胎毒性和致畸作用。     

2,4,5-trichlorophenoxyacetic Acid: effect on ethylene production by fruits and leaves of fig tree

Production of ethylene by fruits and leaves of the fig tree was stimulated by the application of 2,4,5 trichlorophenoxyacetic acid (20 parts per million) to levels that apparently were responsible for hastened matura tion of fruit, epinasty, and senescence of leaves.     

基于Xcm I酶切的pUC19-T载体的构建

[目的]构建以pUC19质粒为基础可利用Xcm I内切酶制备的T栽体。[方法]化学合成2条含有双XcmI酶切位点的互补寡聚核苷酸链,经过变性、复性后克隆入pUCl9质粒的HindIII和BamHI位点之间,通过XcmI酶切后得到一个线性化的带有3’末端突出一个T碱基的T栽体。[结果]经TA克隆验证,制备的pUC19-HB-T载体对PCR产物的克隆率达到95％以上。[结论]构建的pUC19-HB-T载体可用于PCR产物的克隆、测序及后续分子生物学操作。