Novel Reticular Cyclen‐Based Polymer as Gene Vector in DNA Transfection

This study provided an experimental evidence for the use of cyclen (1, 4, 7, 10‐tetraazacyclododecane)‐based polymer for gene delivery. The interesting interaction of the polymer with plasmid DNA was studied by using fluorescence titration, circular dichroism spectra, agarose gel electrophoresis and atomic force microscopy. It was found that polyplex was formed between the polycation and plasmid DNA. The results demonstrated that the cyclen‐based polymer could act as non‐viral gene vector with relatively low cytotoxicity.     

L-丙交酯与环氧氯丙烷共聚物的合成与表征

以系列烷基铝为催化剂,制得丙交酯与环氧氯丙烷的共聚物。分别考察了Al(Oct)_3、Sn(Oct)_2·4Al(Oct)_3、Al(Oct)_3·0.5H_2O、AlEt_3、AlEt_3·0.5H_2O催化下聚合的情况,结果表明:认为在烷基铝的催化下,丙交酯和环氧氯丙烷可以共聚,其中部分水解烷基铝催化效果较好。聚合反应的最佳温度为100℃。在此温度下,随着反应时间的增加,共聚物的分子量和产率皆提高。环氧氯丙烷用量增加,聚合物的产率和分子量呈下降趋势。用~1H-NMR、GPC、DSC对产物进行测试和表征。     

淀粉微球的制备及性能试验

以玉米淀粉为原料，环氧氯丙烷为交联剂，采用逆相悬浮交联聚合法合成了淀粉微球。电镜扫描显示，微球为圆形，表面粗糙，以酮洛芬为模型药物，微球吸附载药量为140mg／g。     

Rejoining of DNA strand breaks induced by propylene oxide and epichlorohydrin in human diploid fibroblasts

The repair kinetics of DNA single- and double-strand breaks (SSBs, DSBs) induced with two carcinogenic epoxides, propylene oxide (PO) and epichlorohydrin (ECH), was studied in human diploid fibroblasts. The methods used were: alkaline DNA unwinding (ADU), the comet assay, and pulsed field gel electrophoresis (PFGE). About 70% of SSBs, measured by ADU, were rejoined after the treatment with 5 mMh and 10 mMh of PO within 20 hr, and the half-life was estimated to be ∼15 hr. On the other hand, effective rejoining of SSBs after ECH treatment was observed only at a dose of 1 mMh (a half-life of ∼15 hr), whereas after 2 mMh treatment, only 26% of SSBs could be rejoined within 20 hr. Furthermore, the use of the comet assay demonstrated that DNA strand breaks were effectively rejoined after PO and ECH treatment at doses of 5–10 mMh and 0.5–1 mMh, respectively. About 76% and 83% of DSBs induced by 5 and 10 mMh of PO, respectively, were rejoined within 4 hr after the treatment (a half-life of ∼2.5 hr), with little further repair thereafter. At lower dose of ECH (1 mMh) a half-life for DSBs rejoining was estimated to be ∼2 hr; however, only 29% of DSBs were rejoined within 2 hr at the higher dose of 2 mMh. After 18 hr, the rejoining following treatment with a lower dose was negligible. At a higher dose, a rapid accumulation of DSBs was observed, probably as the result of cell death and DNA degradation. The results demonstrate the capability of human diploid fibroblasts to repair DNA SSBs and DSBs at low-to-moderate doses of the epoxides. A weak capacity to rejoin DNA strand breaks induced by higher doses of ECH may be a consequence of its higher DNA alkylation activity and approximately 10 times higher toxicity compared to PO. Environ. Mol. Mutagen. 32:223–228, 1998 © 1998 Wiley-Liss, Inc.     

甲磺司特的合成

目的优化甲磺司特合成路线及工艺条件,使其适合工业生产。方法以环氧氯丙烷为起始原料经过醚化和环合“一锅法”、再醚化、催化氢化、酰化、成盐5步反应合成了甲磺司特。结果合成得到目标产物,纯度大于99％,总收率37．2％,产物经MS、1^H-NMR、IR、元素分析等方法确证了结构。结论与文献报道的路线相比,本研究较详细考察了合成工艺,摸索出了最佳的投料方式,优化了原料配比,缩短了反应时间,简化了合成工艺。     

Conditions affecting the mutagenicity of trichloroethylene in Salmonella

Trichloroethylene (TCE) is a high production volume chemical frequently stabilized with oxiranes. These oxiranes may be responsible for the mutagenic activity of TCE in Salmonella, which has been occasionally, but not consistently, reported. High purity and oxirane-stabilized TCE samples were tested for their mutagenic potential in Salmonella typhimurium strains TA 1535, TA 98, and TA 100. Stabilized TCE was tested using a preincubation protocol up to a dose level of 10,000 micrograms per plate, but no mutagenic response was observed in either the presence or absence of a supplementary metabolic activation system (S9 mix) derived from Aroclor 1254-induced male rat liver. TCE without oxirane stabilizers also was nonmutagenic when tested in a vapor delivery system at nominal concentrations of up to 20% and using S9 mix derived from either rat or hamster. TCE containing 0.5-0.6% 1,2-epoxybutane did induce mutagenic responses from strains TA 1535 and TA 100 in the presence and absence of S9 mix. The lowest effective dose was about 0.63% in TA 1535 in the absence of S9 mix. Vapor-phase tests with 1,2-epoxybutane showed that an atmospheric concentration of 0.009% could induce 12-fold and 3-fold increases, respectively, in strains TA 1535 and TA 100. These increases would account for the mutagenic activity of the stabilized TCE sample. Epichlorohydrin (another commonly used stabilizer) induced similar increases in mutant numbers at an atmospheric concentration of 0.0009%. The absence of a significant response caused by unstabilized TCE in the presence of S9 mix is probably due to a lack of assay sensitivity, since chloral, a metabolite of TCE, is a mutagen in TA 100 [Haworth et al.: Environ Mutagen [Supplement 1] 5:3-142, 1983].     

毛细管气相色谱法测定萘哌地尔中的残留溶剂

目的:建立气相色谱法分离测定萘哌地尔中的残留溶剂:乙醇、乙酸乙酯、氯仿、正丁醇、环氧氯丙烷。方法:以RX-5弹性石英毛细管柱为色谱柱(25m×0.32 mm),载气为氮气,采用氢离子火焰检测器,进样口温度为220℃,检测器为280℃,柱温采用程序升温,(60℃,保持4min,以10℃·min~(-1)升至100℃,并保持1min,再以25℃·min~(-1)升至220℃保持6 min),以二甲基亚砜为溶剂,进样量1μL。结果:乙醇、乙酸乙酯、氯仿、正丁醇、环氧氯丙烷的的进样量分别在25～400ng,其峰面积与浓度呈良好的线性关系,加样回收率(n=5)分别为99.47％(RSD<0.76％),99.03％(RSD<1.4%),97.91%(RSD<1.4%),97.90%(RSD<1.4%),98.02(RSD<1.4%),精密度良好。结论:本文气相色谱条件可用于同时测定萘哌地尔中乙醇、乙酸乙酯、氯仿、正丁醇、环氧氯丙烷的含量,方法简单准确。     

端环氧基聚苯乙烯低聚物的合成与表征

在常压、惰性气体保护下,用正丁基锂(n-BuLi)引发苯乙烯阴离子聚合,在添加剂无水三氯化铝的存在下,用环氧氯丙烷(ECH)对聚苯乙烯阴离子进行封端反应,制得分子量约为5×103的末端带环氧基团的聚苯乙烯低聚物。用GPC、FT-IR1、H-NMR及盐酸-二氧六环银量法对低聚物进行了表征,并考察了添加剂、封端反应的温度和时间对环氧端基含量的影响。结果表明:加入添加剂和降低封端温度有利于环氧端基含量的提高,在0℃左右封端效率较高,封端反应时间以1.0 h为宜。     

Occupational dermatosis due to a soil fumigant

D-D mixture is a preplant soil fumigant. It contains dichloropropanes and dichloropropenes, epichlorohydrin and is known as a primary irritant. Three cases of untoward reaction to D-D are reported. By patch testing, the existence of a contact allergic sensitivity to D-D could be proved in one patient. The other two cases reacted negatively; they were probably of a primary irritant origin. Patch tests with compounds related to D-D suggest that the cause of contact allergy must be sought in the propene(s) fraction of D-D. In future cases of untoward reactions to D-D, patch testing appears to be necessary in order to differentiate between a contact allergic and a primary irritant reaction.