Paeonol promotes arylamine N‐acetyltransferase activity in human bladder tumor cells

Paeonol was used to determine effects of arylamine N‐acetyltransferase (NAT) activity in human bladder tumor cells. The NAT activity was measured by high performance liquid chromatography assaying for the amounts of N‐acetyl‐2‐aminofluorene (2‐AAF) and N‐acetyl‐p‐amino‐benzoic acid (N‐Ac‐PABA) and remaining 2‐aminofluorene (2‐AF) and p‐aminobenzoic acid (PABA). The NAT activity in human bladder tumor cells was promoted by paeonol in a dose‐dependent manner, i.e. the higher the concentration of paeonol, the higher the promotion of NAT activity. The data also indicated that paeonol increases the apparent values of K_m and K_max from human bladder tumor cells in cytosols and intact cells. This report is the first demonstration to show paeonol did promote human bladder tumor cell NAT activity.     

活性氧介导砷诱导的蚕豆保卫细胞死亡

采用蚕豆(Vicia fabaL.)表皮条生物法,研究砷的细胞毒性作用机制。结果发现,一定浓度的NaAsO2可使气孔保卫细胞活性降低,部分细胞死亡,细胞死亡率呈浓度依赖性增高;砷处理组保卫细胞内活性氧(reactive oxygen species,ROS)水平升高。抗氧化剂抗坏血酸和过氧化氢酶及Ca2+特异性螯合剂EGTA、Ca2+通道抑制剂LaC13与NaAsO2共同作用时,砷诱发的细胞死亡被显著抑制;MAPK激酶抑制剂PD98059亦能有效阻止NaAsO2诱发的细胞死亡。研究结果表明,砷胁迫引起的胞内ROS合成增加可能通过Ca2+信号途径介导了保卫细胞的死亡过程,MAPK途径参与了砷诱导的细胞死亡。     

Isochromosome 5p mosaicism at prenatal diagnosis: observations and outcomes in six cases at chorionic villus sampling and one at amniocentesis

We present six cases of 47,+i(5p)/46 mosaicism diagnosed at chorionic villus sampling (CVS), this being the first prospective series to be reported. The clinical indication in each was advanced maternal age. Further prenatal studies in four (amniocentesis, plus fetal blood sampling in one) did not show the isochromosome. In one case, subsequent amniocentesis showed 1/48 in situ colonies with the isochromosome, but fetal blood was karyotypically normal. These five pregnancies resulted in phenotypically normal livebirths; further normal follow-up reports (from age 4 months through 4 years) are noted in four of these. Analysis of placental tissue in one case confirmed the presence of the i(5p) mosaicism. In the remaining case, in which 100% of CVS cultured cells had the i(5p), the pregnancy was terminated. Fetal skin fibroblasts did not show the i(5p). Thus, in none of these six cases was true fetal mosaicism detected, nor an abnormal phenotype noted. We suggest that a 47,+i(5p)/46 karyotype, detected at CVS, may frequently reflect confined placental mosaicism. In addition, we report a case of the primary diagnosis of 47,+i(5p)/46 mosaicism at amniocentesis. The infant appeared normal at birth, but a brain malformation was subsequently identified. Copyright © 2002 John Wiley & Sons, Ltd.     

Duplication of 9 p11.2-p13.1: a benign cytogenetic variant

The detection of very rare variants in prenatal diagnosis often causes counseling difficulties and anxiety in parents. We describe a duplication of the proximal region of chromosome 9 short arm in two cases of prenatal diagnosis and in one young woman, with evidence that such rearrangement is an uncommon variant. The duplication was investigated using Fluorescence in situ hybridization (FISH). Although the cytogenetic findings were indicative of a ‘duplication 9p syndrome’ associated with mental and developmental retardation, we were able to demonstrate that the rearrangement was a heteromorphism with no phenotypic consequence. We also determined the breakpoint regions of the rearrangement and identified the BAC probes that precisely define the duplicated region devoid of risk of phenotypic effects. Copyright © 2004 John Wiley & Sons, Ltd.     

UV/Fenton反应对直接黑38的脱色与矿化

为了研究过程参数对photo-Fenton法降解偶氮染料直接黑38人工废水的影响,进行了实验室规模的UV/Fenton反应光催化降解染料直接黑38的研究。在一定的时间段内检测水溶液直接黑38的UV吸光度、总有机碳(TOC)浓度的变化,确定了直接黑38废水的降解速度。以单因素实验方法确定了pH值、[Fe2+]、[H2O2]比例及其初始浓度对降解速度的影响。实验结果表明,在pH为3,染料浓度为30mg/L,[Fe2+]/[H2O2]比例1:100,[Fe2+]=0.12mmol/L,[H2O2]=12mmol/L条件下,UV/Fenton方法能在50min内使染料脱色率达90%,使TOC的去除率达到57%。实验证明了photo-Fenton法对于含有偶氮染料废水的脱色与矿化具有很好的应用前景。     

BDE-47对人胚肾细胞HEK293的毒理效应及作用机制

2,2’,4,4’-四溴联苯醚(BDE-47)是生物体中含量最高且毒性最强的PBDEs之一,有关BDE-47对肾细胞的毒性及其作用机制的研究仍有待补充。选取3个剂量组(低:10-6mol·L-1、中:10-5mol·L-1、高:10-4mol·L-1)及溶剂对照组,研究了BDE-47对人胚肾细胞(HEK293)的细胞凋亡率及活性氧(ROS)水平的影响;并从分子水平对细胞氧化损伤、凋亡相关蛋白(APE1及p53)及凋亡相关基因m RNA(p53、Bax、Caspase 3、Caspase 8)的表达量进行测定。实验结果显示:与对照组相比,中、高剂量组细胞凋亡率显著增加(P0.05);ROS水平在中剂量组显著上升(P0.01);随BDE-47浓度的变化,APE1蛋白表达量与细胞ROS水平存在一致性;p53、Bax、Caspase 8 m RNA表达量与BDE-47的浓度间存在剂量-效应关系。结果表明,BDE-47可诱导HEK293细胞凋亡及氧化应激,APE1可能是细胞ROS升高与细胞凋亡间重要的中介因子;BDE-47可以通过影响Caspase 8及线粒体途径中p53及Bax的表达诱导细胞凋亡。     

卤代烃作为降解抑制剂降低气相色谱/质谱分析方法中p,p’-DDT的降解

因为降低p,p’-DDT降解的传统方法会需要频繁清洁色谱系统及更换相关耗材,操作繁琐,耗时长,成本高,所以拟采用微量降解抑制剂减少和延缓p,p’-DDT分析时的降解率和降解频率。降解抑制剂为常见卤代烃类化合物,如四氯化碳等,降解抑制剂与样品同时进样分析。与传统方法比较,本方法不仅无需频繁清洁色谱系统及更换相关耗材,而且能显著降低p,p’-DDT降解率和降解频率,节约耗材及时间成本,操作简单快捷,不影响其它化合物的分析,回收率满足相关标准要求,为减少色谱分析中易降解化合物的降解提供了新的方法和思路。     

附载二氧化钛光催化降解水中对氯苯胺(PCA)

以紫外灯为光源 ,附载在镍网上的 TiO₂ 为催化剂 ,研究水中 PCA光催化降解动力学行为和机理 .结果表明 ,PCA的降解符合准一级动力学方程 ;初始 pH4～11对其反应速率影响较小 ;增大氧气浓度能加快 PCA的降解和脱氯速率 ;外加电位能大幅度提高 PCA的降解速率 .通过 GC-MS技术确定其降解中间产物主要有苯胺、硝基苯、对氯硝基苯、偶氮苯、4,4′-二氯偶氮苯等 ,它们最终矿化为 NH⁺₄、Cl^-、NO^-₃ 和 CO₂ .光催化能有效地降解 PCA但其矿化比降解需要更长的时间 .     

新试剂NBTDAPNP的合成及与镉的显色反应

阐述了新试剂 6 -硝基 -苯并噻唑 -重氮氨基 - 4-硝基苯的合成方法、结构鉴定、分析性能及在光度分析中的应用。该试剂对镉有很高的显色灵敏度 ,ε4 55可达 2 43× 10 5L/mol·cm ,用分光光度法可直接测定水样中镉 ,与原子吸收光谱法结果一致。