铅的肾脏毒性与细胞凋亡的关系

为了解铅的肾脏毒性以及与细胞凋亡的关系，建立原位末端标记法检测细胞凋亡。用醋酸铅腹腔注射染毒大鼠，染毒剂量分别为５，１０，２０ｍｇＰｂ＾２＋／ｋｇ体重，１次／天，共染毒３天，对照组腹腔注射醋酸钠２０ｍｇ Ｎａ＾＋／ｋｇ体重，结果，于染毒第二天开始，各染毒组动物体重的增长速率已开始下降，与对照组比较差异有显著性（Ｐ〈０．０５）。肾脏脏器系数，染毒组显著高于对照组（Ｐ〈０．０５）。染毒鼠的肾脏组织凋亡     

铅染毒对大鼠体内钙、锌、铁元素的影响研究

Wistar大鼠每天腹腔注射醋酸铅649mg/kg,在第4周醋酸铅剂量降至329．5mg/kg,8周停止染毒。结果表明,随着铅染毒,大鼠出现高尿铅、高尿锌、高尿钙;脑、肝、肾中铁、锌、钙却都有不同程度提高,肝脏中锌、钙、铁、肾脏中锌、钙增加极明显;在8周停止染毒后,脑铅含量大幅度降低（P＜0．01）,肝脏铅却梢有上升（P＞0．05）,肾铅急剧增加,从47．9320μmol／L升至633．85μmol／L,大约上升13倍（P＜0．01）。     

急性铅染毒对小鼠行为及脂质过氧化水平的影响

为了解急性铅染毒对小鼠行为及脂质过氧化水平的影响,并探讨两者关系,将48只ICR小鼠随机分为4组,低、中、高铅组小鼠分别予以醋酸铅2、10、50 mg/kg ip染毒,隔日1次,连续3次;对照组予以等量的生理盐水;染毒后作自发活动、Morris水迷宫测试,实验结束时测定血浆、脑匀浆MDA和T-SOD。结果表明,铅染毒小鼠易激惹、多动,逃避潜伏期显著延长(P<0.01)。血浆MDA、T-SOD和脑匀浆MDA明显增高(P<0.01),并与染铅剂量呈正线性相关(P<0.01)。但小鼠行为改变与脂质过氧化水平之间关系不明显。结论是急性铅染毒能够影响小鼠的行为,呈现激惹、多动及学习记忆能力减退;急性铅染毒能提高小鼠脂质过氧化水平,并可代偿性提高机体T-SOD活性,但脂质过氧化水平增高是否为急性铅中毒行为改变的机制之一尚有待进一步研究。     

孕鼠胎盘膜对混合稀土常乐的屏障作用

为评估混合稀土常乐对人体胚胎的潜在危害, 在光镜和电镜下观察了混合稀土常乐染毒后的胎盘组织, 以了解其在胎盘组织中的存在形式和分布情况, 同时应用电感耦合等离子体质谱法(ICP-MS)检测染毒后的孕鼠血清、胚胎组织提取液和羊水中的稀土含量以确定其能否通过胎盘屏障. 染毒于雌鼠妊娠第六天开始, 每天分别以0.3, 2, 5和20 mg·kg-1混合稀土常乐灌胃, 直至妊娠第十八天. 结果显示: 光镜下, 染毒组胎盘绒毛中毛细血管周围合体细胞滋养层胞质内积聚有许多圆形黑色细小颗粒, 颗粒的多少与染毒剂量呈正相关; 电镜下, 染毒组胎盘绒毛中可见有膜包裹的致密体及合体细胞滋养层细胞内线粒体有不同程度的空泡变和嵴断裂; ICP-MS检测: 孕鼠血清铈的含量随染毒剂量的增加而递增, 染毒组胎儿羊水和孕鼠血清中稀土总量, 只有20 mg·kg-1组与对照组相比有显著增加, 其余各组均无显著差异. 胚胎组织提取液中各组的稀土总含量没有变化. 由此得出结论: 胎盘膜对混合稀土常乐进入胚体有很大的限制作用, 但是, 当混合稀土常乐在胎盘膜中积累增加到一定程度时, 可少量透过胎盘屏障, 进入胚体.     

酒精处理后鼠脑内单胺氧化酶活性及单胺神经递质代谢变化的测定

应用高效液相色谱法测定了慢性酒精处理后胎鼠脑中单胺氧化酶(MAO)的活性,以及多巴胺(DA)、5-羟色胺(5-HT)和它们的代谢产物的含量。在怀孕的最后一周内对SD母鼠灌胃酒精,对照组用生理盐水处理,分娩后取胎鼠脑组织进行检测。胎鼠脑线粒体MAO的活性随酒精染毒剂量的增加而递减,呈现出剂量反应关系;与盐水对照组相比,酒精暴露可改变胎鼠全脑中DA和5-HT的水平,但统计结果无显著性差异。其中,HVA和5-HIAA的含量在4.0g/kg酒精处理后显著减少(P0.05)。慢性酒精暴露后MAO活性的下降及DA、5-HT的代谢变化可能在中枢神经系统的发育障碍中发挥了重要作用。     

氯化汞和亚硒酸钠对大鼠的毒性相互作用

用Hom法测定了大鼠经口染毒的LD50,并在此基础上进行90天亚慢性经口毒性试验。测量染毒过程中的体重、食物利用率的变化,测定肝、肾、脾等五种器官脏器系数,并进行血液生化检测。氯化汞、亚硒酸钠及二者等摩尔比联合作用对大鼠LD50分别为127．5、39．55和252mg/kg。汞组和硒组大鼠体重呈进行性下降。汞组肝、肾、胸腺、脾系数增大,睾丸系数减小,联合作用显著降低了汞对各脏器系数的影响,并且随着剂量组中硒剂量的增加,汞对脏器系数的影响减弱。血液学、血清酶化学检测结果无显著性差异。实验结果表明氯化汞和亚硒酸钠相互作用表现为明显的毒性拮抗作用,雌鼠对氯化汞和亚硒酸钠联合毒性有更高的耐受性。联合作用能够减弱单独作用对大鼠生长的影响,减弱汞对五种脏器的毒性。     

铅对泌尿系统的影响

铅对肾脏的毒性作用分为急性铅肾病和慢性铅肾病两类。铅对肾的急性毒性作用部位主要是肾近曲小管 ,主要病理学和功能性改变为 :①肾小管上皮细胞核内包涵体的形成 ;②肾小管上皮细胞核增大、线粒体功能和超微结构异常 ;③肾小管对葡萄糖、氨基酸和磷的吸收受损。一般说来 ,铅的早期或急性肾毒性的表现是轻微的 ,局限于肾小管上皮细胞 ,损伤是可逆的 ,经驱铅治疗可排出包涵体 ,恢复改变的线粒体形态和功能 ,肾小管功能也可恢复正常。长期接触铅可对肾脏功能产生慢性损伤 ,其主要病理特点为 :①肾间质纤维化和肾小管上皮细胞萎缩 ;②近曲小管…     

三氯化铝染毒小鼠血清和脾脏锌、铜含量测定

测定了三氯化铝（Ａ１Ｃ１３）染毒小鼠血清和脾脏微量元素Ｚｎ、Ｃｕ含量,从微量元素角度探讨了铝对小鼠免疫功能的影响。实验用健康成龄小鼠３０只,随机分为３组：正常对照组（简称对照组）、Ａ１Ｃ１３低剂量染毒组（简称低铝组）和Ａ１Ｃ１３高剂量染毒组（简称高铝线）。实验结束后测定血清和脾脏微量元素Ｚｎ、Ｃｕ含量,数据均经统计学处理。结果表明,Ａ１Ｃ１３使小鼠血清和脾脏Ｚｎ含量下降。与对照组比较,低铝组Ｐ〈０     

立得益片对铅中毒小鼠(生殖系统、脑、血液、心脏)促排铅的作用

研究了立得益片对铅中毒小鼠促排铅的作用。给小鼠腹腔注射醋酸铅溶液染毒 7d ,建立铅中毒模型后 ,灌胃给药不同剂量立得益片及阳性对照药物EDTA ,极谱法测定不同时间生殖系统、脑、血液、心脏中的铅含量 ,观察及统计立得益片对铅中毒小鼠上述各脏器的促排铅作用。结果表明 ,铅中毒小鼠给药 6、 1 3d后脑、心脏、血液中的铅含量明显下降 ,生殖系统中仅卵巢和子宫中的铅含量在给药 1 3d后 ,立得益片高剂量组与模型对照组有显著性差异 (P <0 0 1 )。提示立得益片对铅中毒小鼠血液及脏器有明显促排铅作用 ,降低机体的铅负荷且存在时效、量效关系     

富锌排铅咀嚼片对铅染毒大鼠的排铅作用

研究了富锌排铅咀嚼片 (RZLR)对实验性铅染毒大鼠的排铅作用。将 48只 1 0 0～ 1 40g雄性大鼠 ,按质量随机分成空白对照组、阳性药物组、模型对照组、低剂量组、中剂量组和高剂量组 ,每组 8只。空白对照组自由饮水 ,其它五组饮用 2 0 0mg/L的醋酸铅水溶液染毒。 3 0d后 ,剂量组以人体摄入量 (按人体质量计 0 1g/kg)的 5、 1 0、 3 0倍经口灌胃 ,阳性药物组灌胃二巯基丁二酸 (DMSA) ,空白对照组和模型对照组每天灌水。一个月后测定血、肝脏及胫骨中的铅含量。结果表明 ,RZLE组与模型对照组相比 ,大鼠血铅、胫骨中铅明显降低 (P <0 0 5 )。按照《保健食品功能学评价程序和检验方法规范》标准判定 ,富锌排铅咀嚼片有促进动物排铅的作用。     

碳苷研究 V: 用Grignard试剂合成取代苯酚中酚羟基的保护及脱保护

本文报道了一些取代苯酚的合成, 并探讨了用Grignard试剂合成取代苯酚中酚羟基的保护及脱保护的问题. 利用苄基和甲基作为酚羟基的保护基, 对文献报道的切断醚键脱保护方法进行了评价. 找到了两种新体系能在更温和条件下切断醚键的方法, 指出了它们的适用条件. 实验结果符合硬软酸碱理论.     

Effect of Alkyl Chain Length of N-Alkyl-N′-(2-benzylphenyl)ureas on Gelation

Urea derivatives that were substituted with a 2-benzylphenyl group and an alkyl group functioned as low molecular weight gelators for various organic solvents and ionic liquids. Urea derivatives with long alkyl chains were effective for the gelation of polar solvents. However, they were not suitable for the gelation of non-polar solvents, whereas urea derivatives with short alkyl chains were effective. Ionic liquids were similar to polar solvents in that urea derivatives with long alkyl chains were the most effective gelators. The physical properties of the formed supramolecular gels were analyzed by dynamic viscoelasticity measurements using a rheometer.     

FT-IR, FT-Raman spectra, density functional computations of the vibrational spectra and molecular geometry of biomolecule 5-aminouracil

FT-IR and FT-Raman spectra of the biomolecule 5-aminouracil were recorded in the regions 400–4000 cm⁻¹ and 10–3500 cm⁻¹, respectively. The observed vibrational wavenumbers were analyzed and assigned to different normal modes of vibration of the molecule. Density functional calculations were performed to support wavenumber assignments of the observed bands. A comparison with the molecule of uracil was made, and specific scale factors were employed in the predicted wavenumbers of 5-aminouracil. With the purpose of study the important molecule 5-aminouracil, its equilibrium geometry and harmonic wavenumbers were calculated for the first time by the B3LYP DFT method. The vibrational wavenumbers were compared with IR and Raman experimental data. Also good reproduction of the experimental wavenumbers is obtained and the % error is very small. All the tautomeric forms of 5-aminouracil were determined and optimized. The dimer forms were also simulated. The energy, atomic charges and dipole moments were discussed and several general conclusions were underlined.     

Preparation and properties of polyurethane networks based on α,ω-difunctional poly(hexafluoropropylene oxide)

Poly(hexafluoropropylene oxide), poly(HFPO), networks were prepared from functional polymers by end linking via urethane groups. The prepolymers were characterized by NMR spectroscopy and GPC. The networks were characterized by determination of the number of network chains from the shear modulus, and were snown to contain both trifunctional crosslinks and difunctional links. The properties of the networks were investigated by a range of techniques. Compared with fully-fluorinated networks formed via triazine cross-links, investigated previously, the urethane-linked networks were more readily prepared but were poorer elastomers, were less thermally stable, and were less resistant to swelling by common polar solvents. © 1995 John Wiley & Sons, Inc.     

南瓜籽烘烤前后化学成分的分析

对烘烤前后南瓜籽中的化学成分进行分析并对比。采用同时蒸馏萃取装置萃取南瓜籽中的挥发性成分,采取超临界CO2萃取技术萃取南瓜籽油脂,并将其分为酸、碱、中性三个部分,用气相色谱-质谱联用方法分析其中化学成分并进行对比。结果表明,南瓜籽挥发性成分中含有多种醛类和酯类化合物,烘烤后产生了大量的烷基吡嗪,其在碱性部分中的相对含量比烘烤前提高14倍多,不饱和醛类化合物含量也有明显提高。南瓜籽油脂中的主要化学成分是油酸、亚油酸及其酯类。还含有生物活性功能成分如植物甾醇、角鲨烯和维生素E等。烘烤后除角鲨烯含量有所降低,维生素E、植物甾醇、亚麻酸等均有提高。     

Preparation of Titania/PDMS Hybrid Films and the Conversion to Porous Materials

Transparent films of titania/poly(dimethylsiloxane) (PDMS) hybrids were prepared by the solvent evaporation from the precursor solution prepared by the co-hydrolysis and co-condensation of titanium tetraisopropoxide and a methoxy-functionalized PDMS. The hybrid films were flexible and had high homogeneity of the composition. The organic groups of PDMS were decomposed at 400°C in air to form porous films. Though the heated films were rather brittle compared to the as-synthesized films, they were still transparent and homogeneous. The BET surface areas of the films after the heat treatment at 400°C were over 300 m²/g, while the as-synthesized hybrid films were non porous. According to the BDDT classification, the nitrogen adsorption/desorption isotherms of the calcined films were Type I, showing that the films were microporous. The titania domains were still amorphous after the heat treatment at 400°C and transformed to anatase after the heat treatment at 1,000°C.     

国标测定土壤中铅测定方法改进的探讨

为改进测定土壤中铅的石墨炉原子吸收法,通过湿法消解,应用基体改进剂磷酸二氢铵,提高方法的准确度和精密度.结果表明,方法的线性范围为0.0 ～ 50.0 μg/L,检出限为0.21mg/kg,回收率为82.6％～94.4％,该方法具有干扰因素少,灵敏度高、准确的特点,可推广应用.     

Polyimide-Silica Hybrids: Spectroscopy,Morphology and Mechanical Properties

Polyimide/silica hybrids were prepared by a sol-gel process and were evaluated in terms of curing behaviour, morphology and mechanical properties. The spectroscopic examination showed that the presence of the inorganic phase accelerates the imidization of the polyamic acid. Two types of morphology for the silica phase were obtained by tailoring the composition of the precursor solution mixture. The mechanical properties were found to be strongly dependent on the system morphology. The largest increase in rigidity and strength properties were achieved when the two phases were co-continuous.     

云南菊科中草药中铅含量特征分析

论述了云南２７种菊科中草药及其水提取物中铅含量的特征。菊科植物及水提物中铅含量的频数分布为正偏态,两者的相关系数ｒ＝０．０９,未呈现显著的线性相关。提取率较高的山紫苑、佩兰、木香铅实际含量低;铅含量高的叶下花、狭叶兔耳风、臭灵丹提取率又较低,减少了人体对Ｐｂ的过量摄入。     

等离子体发射光谱法测定茶水中无机元素的含量

采用电感耦合等离子体发射光谱法对茶水中的无机元素进行分析,对其中的Cu、Zn、Mn、P、Fe5种元素进行定量,讨论了等离子体发射光谱法最佳实验条件及影响茶叶中无机元素浸出量的因素。Cu、Zn、Mn、P、Fe的回收率为92．5％～103．5％,测定结果的相对标准偏差为1．34％-4．5％（n=5）。