棒丝氨酸的全合成研究I. 从D-葡萄糖合成3-[3'R, 5'S)-7'-氧代-1'-氮杂-4'-氧杂双环[3.2.0]-庚-3'-基]-3-O-苄基-(2S, 3S)-丝氨酸及其(3'R, 5'R)-差向异构体

以D-葡萄糖为原料经侧链氨基酸合成, 与β-内酰胺缩合, 唑烷环合和除保护基等反应合成了棒丝氨酸的O-苄基衍生物, 3-[3'R, 5'S)-7'-氧代-1'-氮杂-4'-氧杂双环[3.2.0]-庚-3'-基]-3-O-苄基-(2S, 3S)-丝氨酸及其(3'R, 5'R)-差向异构体(18)。     

卡那霉素作为手性选择剂的毛细管电泳手性药物分离研究

建立了一种以天然易得的卡那霉素为手性添加剂，用毛细管区带电泳法快速分离市售对乙肝有良好治疗效果的药物联苯双脂衍生物的方法，拓宽了毛细管电泳中手性选择剂的范围，通过实验研究了卡那霉素、甲醇 含量PH值，磷酸盐缓冲体系和硼硝缓冲体系对手性分离的影响，以及三种有机溶剂（甲醇、乙晴、异丙醇）添加剂对手性分离的影响，结果表明，在含有3％卡那霉素，30mol/L，硼砂缓冲体系（PH＝8．0）添加30％异丙醇是最佳的分离条件。     

流动注射-化学发光法测定头孢拉定

1　引　　言头孢拉定 (ｃｅｐｈｒａｄｉｎｅ ,ＣＥＰ)是广泛用于临床治疗的一种头孢类抗生素药物。目前对其测定的主要方法有高效液相色谱法、分光光度计、荧光法和吸附极谱法等。利用Ｃｅ 与某些含巯基的化合物作用产生化学发光从而测定这些化合物的研究已有文献报道 ,但未见用于头孢拉定的测定。头孢拉定的降解产物含有巯基 ,本文采用流动注射技术考察了该降解产物与Ｃｅ 作用产生化学发光的条件 ,发现罗丹明 6Ｇ对该化学发光体系有很强的增敏作用 ,据此建立了测定头孢拉定的新方法。该方法用于胶囊中头孢拉定含量的测定 ,结果令人满意…     

聚(ε-己内酯)-多肽共聚物胶束增强抗生素的抗菌活性

Bacterial infection is a major threat to human health, and can cause several diseases including gastroenteritis, influenza, tetanus, and tuberculosis. As conventional antibiotic treatment may cause various undesirable effects such as stomach disorder and bacterial resistance, it is necessary to improve the antibacterial efficiency of antibiotics. Here, we synthesized a peptide-based copolymer, poly(ε-caprolactone)-block-poly(glutamic acid)-block-poly(lysine-stat-phenylalanine)[PCL₃₄-b-PGA₃₀-b-P(Lys₁₆-stat-Phe₁₂)] by ring-opening polymerization (ROP) of ε-caprolactone and amino acid N-carboxyanhydride (NCA). Successful synthesis of the copolymer was verified by proton nuclear magnetic resonance and size exclusion chromatography. This copolymer can self-assemble into negatively charged micelles (-26.7 mV) under alkaline conditions by solvent switch method. The micelle structure was confirmed by transmission electron microscopy and dynamic light scattering, and revealed to have a diameter of ~42 nm. Antibiotics were loaded into micelles during the self-assembly process, and cell viability assay was conducted to evaluate its cytotoxicity with and without tobramycin. No obvious cytotoxicity was observed for both micelles when the concentration was lower than 300 μg·mL^-1. The antibiotic-loaded micelles demonstrated very low minimum inhibitory concentrations (MICs) against both Gram-negative Escherichia coli (E. coli) (7.8 μg·mL^-1) and Gram-positive Staphylococcus aureus (S. aureus) (18.2 μg·mL^-1), while the MICs of free tobramycin were 3.9 and 1.0 μg·mL^-1, respectively. The drug-loading content and efficiency of the micelles were 5.2% and 24.3%, respectively. Therefore, the MICs of the loaded tobramycin against E. coli and S. aureus were 0.4 and 0.9 μg·mL^-1, respectively, suggesting that the micelle could enhance the antibacterial activity of antibiotics. Tobramycin-loaded micelles demonstrated a sustained release characteristic, with 85% of the antibiotics released after 8 h. In bacteria-induced acidic microenvironment, the coil conformation of PGA blocks transforms and PGA blocks shrink toward the micelle core. Concomitantly, the carboxyl side chains are protonated in an acidic environment, increasing the hydrophobicity of this micelle. Antibiotics will be captured when reaching the outer core to slow down the releasing process. Furthermore, the poly(lysine-stat-phenylalanine) [P(Lys-stat-Phe)] coronas with broad spectrum intrinsic antibacterial activity can penetrate the bacterial cell membrane, leading to leakage of the cellular contents of the bacteria and ultimately their death. Due to the sustained release property of micelle and the intrinsic activity of the antibacterial peptide segments, this micelle can greatly enhance the antibacterial activity of antibiotics. Overall, this antibiotic-loaded micelle provides a novel approach for significantly reducing the antibiotics dosage and avoiding the associated health risks.     

固相萃取-液相色谱-串联质谱法测定废水中12种抗生素的含量北大核心CSCD

取500 mL废水样品,用6 mol·L^(-1)盐酸溶液调节溶液酸度至pH 2.0~4.0后,再加入150 mg抗坏血酸和250 mg乙二胺四乙酸二钠。采用HLB固相萃取柱富集净化,用10 mL甲醇分两次洗脱。将洗脱液氮吹至近干,加入25μL内标溶液,用初始比例流动相定容至1.0 mL,经0.22μm有机滤膜过滤,得待测液。以ZARBAX Eclipse Plus C_(18)色谱柱为固定相,以不同体积比的甲酸-甲醇-乙腈-水的混合液为流动相进行梯度洗脱。质谱分析采用电喷雾正离子(ESI^(+))源和多反应监测(MRM)模式检测,内标法定量。结果显示:12种抗生素标准曲线的线性范围均为2.00~200μg·L^(-1),检出限(3.143s)为0.001~0.007μg·L^(-1);对空白样品进行3个浓度水平的加标回收试验,回收率为60.1%~125%,测定值的相对标准偏差(n=6)为2.8%~13%。方法用于实际水样分析,结果显示5个不同来源的水样中均不同程度地检出抗生素。     

北京已建20家超级细菌监测网细化监测网点

针对我国发现的3例“超级细菌”病例,目前北京市已经将细菌监测网点增至20家并进一步细化监测。一旦发现对抗生素免疫的“超级细菌”,将及时调整该种抗生素的使用情况。我国10月27日报告已发现3例超级细菌（NDM-1耐药基因细菌）病例。对此,北大临床药理研究所常务副所长吕媛介绍,北京市已建设细菌监测网。目前哨点医院已从19家增加至20家。     

5－羟甲基－5－壬烷基戊内酯的合成

以已二酸为原料，经六步反应合成了５－羟甲基－５－壬烷基戊内酯，在形成手性中心的关键反应步骤中使用了（３Ｓ，４Ｓ）－１－苄基－１－甲基－３，４－二羟基吡咯碘化铵作手性相转移催化剂。     

固相萃取-高效液相色谱法同时测定鸡粪中四环素类、喹诺酮类和磺胺类抗生素

建立了一种高效、低成本的固相萃取-高效液相色谱（SPE-HPLC）同时测定鸡粪中6种常见抗生素（2种四环素类、2种喹诺酮类和2种磺胺类）的分析方法。样品经EDTA-McIlvaine缓冲液和有机混合提取液（甲醇-乙腈-丙酮，2：2：1，v/v/v）提取，过HLB固相萃取柱净化，甲醇-二氯甲烷（7：3，v/v）洗脱，高效液相色谱-二极管阵列检测器测定，检测波长λ=270 nm，柱温32℃，流动相为乙腈-0.7%（v/v）磷酸水溶液。该方法在0.5~100 mg/L质量浓度范围内的标准曲线相关系数r²在0.9999~1之间，样品加标回收率在70.0%~116.3%之间，相对标准偏差为1.2%~16.6%。方法检出限为1.3~6.7 μg/kg，定量限为3.5~9.2 μg/kg。应用该方法对辽宁省抚顺市某养鸡场当天的鸡粪进行检测，诺氟沙星和恩诺沙星（喹诺酮类）含量为未检出~9.23 mg/kg和1.57~7.69 mg/kg，磺胺二甲嘧啶（磺胺类）含量为2.02~13.05 mg/kg，磺胺甲恶唑、土霉素和四环素未测出。     

医院感染的相关因素

１９９９年６月～２０００年６月全部住院患者共计８１１５例,按照中华医院管理学会制订的医院感染诊断标准统计．发生医院感染病例３７３例．医院感染发生率为４．６％．１．感染部位的分布 医院泌尿道感染占２６．９６％上呼吸道占２０．６５％,下呼吸道感染占１６．８８％,其它部位感染占１３．３５％,胃肠道感染占７、８１％,皮肤与软组织感染占６．８０％,手术切口感染占６．０５％,血液感染占１．５ｌ％．２．易感人群 脑血管疾病１６．３３％,肾炎肾病１０．５３％,糖尿病８．４２％,恶性肿瘤８．２８％,肝病及肝硬化４．…