PEGylation of Carbonate Apatite Nanoparticles Prevents Opsonin Binding and Enhances Tumor Accumulation of Gemcitabine

pH sensitives carbonate apatite (CA) has emerged as a targeted delivery vehicle for chemotherapeutics agent with tremendous potential to increase the effectivity of breast cancer treatment. The major challenge for intravenous delivery of drug-incorporated nanoparticles is their rapid opsonization, resulting in accumulation within the organs of reticuloendothelial system, such as liver and spleen. Therefore, surface modification by polyethylene glycol was implemented to improve the half-life of drug-particle complexes and enhance their uptake by target tissues. A simple, rapid, and sensitive triple quadrupole liquid chromatography–mass spectrometry method was developed and validated for quantification of gemcitabine in plasma, various organs and tumor tissues of mice with breast carcinoma, whereas sodium dodecyl sulfate-polyacrylamide gel electrophoresis, quadrupole-time of flight liquid chromatography–mass spectrometry and analysis by SwissProt.Mus_musculus database were performed for protein separation, identification, and homology search by comparing the de novo sequence tag. PEGylated CA exhibited almost 6-fold increase in gemcitabine accumulation in tumor with significant reduction in other organs within 1 h of intravenous administration, compared to free drug. In addition, plasma drug amount was found to be higher in PEGylated particles, implying their role in prolonging blood circulation time of particle-bound gemcitabine. Investigation of protein corona composition demonstrated notable reduction in opsonin interactions after PEGylation of CA particles. Overall, the results indicate that the composition and dynamics of protein corona subjected to alteration by PEGylation play crucial roles in affecting successful nanoparticle-based targeted delivery of a cytotoxic drug.     

Penta-block copolymer microspheres: Impact of polymer characteristics and process parameters on protein release

Here, we aimed to develop protein loaded microspheres (MSs) using penta-block PLGA-based copolymers to obtain sustained and complete protein release. We varied MS morphology and studied the control of protein release. Lysozyme was used as a model protein and MSs were prepared using the solid-in-oil-in-water emulsion solvent extraction method. We synthesized and studied various penta-block PLGA-based copolymers. Copolymer characteristics (LA/GA ratio and molecular weight of PLGA blocks) influenced MS morphology. MS porosity was influenced by process parameters (such as solvent type, polymer concentration, emulsifying speed), whereas the aqueous volume for extraction and stabilizer did not have a significant effect. MSs of the same size, but different morphologies, exhibited different protein release behavior, with porous structures being essential for the continuous and complete release of encapsulated protein. These findings suggest strategies to engineer the morphology of MSs produced from PLGA-based multi-block copolymers to achieve appropriate release rates for a protein delivery system.     

Effect of residual doxycycline concentrations on resistance selection and transfer in porcine commensal Escherichia coli

Pig feed may contain various levels of antimicrobial residues due to cross-contamination. A previous study showed that a 3% carry-over level of doxycycline (DOX) in the feed results in porcine faecal concentrations of approximately 4?mg/L.The aim of this study was to determine the effect of residual DOX concentrations (1 and 4?mg/L) in vitro on selection of DOX–resistant porcine commensal Escherichia coli and transfer of their resistance plasmids.Three different DOX–resistant porcine commensal E. coli strains and their plasmids were characterised. These strains were each brought in competition with a susceptible strain in a medium containing 0, 1 and 4?mg/L DOX. Resistant bacteria, susceptible bacteria and transconjugants were enumerated after 24?h and 48?h.The tet(A)–carrying plasmids showed genetic backbones that are also present among human E. coli isolates. Ratios of resistant to susceptible bacteria were significantly higher at 1 and 4?mg/L DOX compared with the blank control, but there was no significant difference between 1 and 4?mg/L. Plasmid transfer frequencies were affected by 1 or 4?mg/L DOX in the medium for only one of the resistance plasmids.In conclusion, DOX concentrations of 1 and 4?mg/L can select for resistant E. coli in vitro. Further research is needed to determine the effect of these concentrations in the complex environment of the porcine intestinal microbiota.     

Clinical characteristics of bacteraemia caused by Burkholderia cepacia complex species and antimicrobial susceptibility of the isolates in a medical centre in Taiwan

This study investigated the clinical characteristics and outcomes of bacteraemia due to Burkholderia cepacia complex (BCC) species among 54 patients without cystic fibrosis from January 2013 to February 2015. BCC isolates were identified to the species level by the Bruker Biotyper MALDI-TOF MS system and by sequencing analysis of the 16S rRNA and recA genes. Antimicrobial susceptibilities of the isolates were determined by the agar dilution method. Sequencing of the recA gene in the 54 blood isolates revealed 37 (68.5%) isolates of B. cenocepacia, 9 (16.7%) of B. cepacia, 4 (7.4%) of B. multivorans and one isolate each of B. arboris, B. pseudomultivorans, B. seminalis, and B. vietnamiensis. The overall performance of the Bruker Biotyper MALDI-TOF MS system for correctly identifying the 54 BCC isolates to the species level was 79.6%, which was better than that (16.7%) by 16S RNA sequencing analysis. Bacteraemic pneumonia (n?=?23, 42.6%) and catheter-related bacteraemia (n?=?21, 38.9%) were the most common types of infection. Higher rates of ceftazidime and meropenem resistance were found in B. cepacia isolates (33.3% and 22.2%, respectively) than in isolates of B. cenocepacia (21.6% and 10.8%, respectively) and other species (12.5% and 12.5%, respectively). Overall, the 30-day mortality rate was 38.9% (21/54). Bacteraemia caused by BCC species other than B. cenocepacia and B. cepacia (adjusted odds ratio [aOR] 20.005, P?=?0.024) and high SOFA score (aOR 1.412, P?=?0.003) were predictive of higher 30–day mortality. Different BCC species are associated with different outcomes of bacteraemia and exhibit different susceptibility patterns.     

采用UPLC-Q-TOF-MS/MS技术分析宛艾化学成分

目的:研究宛艾的非挥发性化学成分,以促进其进一步的研究与开发。方法:采用超高效液相色谱串联四极杆飞行时间质谱(UPLC-Q-TOF-MS/MS),并结合文献报道对宛艾中的化学成分进行鉴定,色谱柱为Agilent Poroshell 120EC-C18(3mm×150mm,2.7μm);流动相为乙腈(A)-0.2%甲酸水溶液(B),梯度洗脱,流速0.5mL·min^-1。结果:鉴定出宛艾中23个化学成分,其中黄酮及黄酮苷类12个,苯丙酸类9个,香豆素类1个,其他1个。结论:本研究阐明了宛艾的非挥发性化学成分,方法精确、高效,适用于宛艾非挥发性化学成分的快速鉴定,为宛艾的深入研究及进一步开发利用奠定了基础。     

苯溴马隆对高尿酸血症模型大鼠脂质代谢的影响

目的 基于脂质组学方法研究苯溴马隆治疗高尿酸血症（hyperuricemia,HUA）大鼠的作用机制,并揭示尿酸水平增高与脂质代谢异常的内在相关性。方法 利用超高效液相色谱-四极杆飞行时间质谱（UPLC-Q-TOF/MS）技术,结合主成分分析（PCA）和偏最小二乘法判别分析（OPLS-DA）研究正常组、模型组和苯溴马隆组的大鼠血清中内源性脂质代谢物的变化,寻找潜在生物标记物,分析相关代谢通路,绘制代谢网络机制图。结果 脂质组学分析发现,苯溴马隆可使HUA大鼠体内水平异常的20个差异代谢物回调到正常水平;相关代谢通路分析发现,苯溴马隆影响果糖诱导HUA大鼠血清中的脂质水平,主要与甘油磷脂代谢通路相关。结论 苯溴马隆对HUA的治疗可能与改善体内甘油磷脂代谢通路异常密切相关。     

UHPLC-MS/MS测定人血浆中美托洛尔的含量

目的 建立测定人血浆中美托洛尔含量的UHPLC-MS/MS分析方法。方法 采用Agilent RRHD PLUS C₁₈色谱柱（2.1 mm×50 mm,1.8 μm）,0.2%甲酸水溶液-乙腈（68∶32）为流动相。质谱采用电喷雾离子源（ESI）,多反应监测（MRM）,检测离子为正离子,分别选择m/z 268/116、237/194作为美托洛尔和内标（卡马西平）的检测离子对。结果 血浆中美托洛尔在1.012~759.0 ng·mL^-1内线性关系良好（r=0.999 2）。高、中、低浓度美托洛尔的基质效应分别为105.9%,106.1%,106.9%;平均回收率分别为83.0%,99.3%,95.2%。批内精密度RSD≤3.22%,批间精密度RSD≤4.14%。结论 该方法简便、灵敏、快速、准确,适用于血浆中美托洛尔的含量测定。     

保健食品中新型二硫代卡地那非类似物的分析鉴定

目的 鉴定保健食品中非法添加的一个未知结构的二硫代卡地那非类似物。方法 采用高效液相色谱-二极管阵列检测器联用（HPLC-DAD）技术进行补肾壮阳类保健食品非法添加筛查时发现一个未知结构的二硫代卡地那非类似物,经过正相硅胶薄层色谱分离纯化得到目标化合物后,用超高效液相色谱-二级质谱联用（UPLC-MS/MS）技术获得其准分子离子和二级质谱图,用核磁共振得到碳谱和氢谱数据,结合文献分析,最终鉴定该化合物的结构。结果 在保健食品中发现了一个新型二硫代卡地那非类似物,结构为3,5-二甲基哌嗪基二硫代去甲卡地那非。结论 该化合物不在现有补肾壮阳类中成药检验标准的13种目标化合物范围内,是一种新的非法添加化学物质。     

基于网络搜索快速鉴定抗风湿类中成药和保健食品中非法添加的非那西丁及小檗碱

目的 鉴定抗风湿类中成药和保健食品中非法添加的2个未知成分。方法 采用高效液相色谱-二极管阵列检测器联用（HPLC-DAD）技术进行抗风湿类中成药和保健食品非法添加筛查时发现2个可疑色谱峰,采用UPLC-MS/MS技术获得其准分子离子和二级质谱图,然后通过网络搜索分析初步确定可疑成分,最后与对照品比较检测,最终确定2个非法添加化合物的结构。结果 在抗风湿类保健食品中检出盐酸小檗碱,中成药中检出非那西丁。结论 这2个化合物不在现有抗风湿类中成药和保健食品检验标准13种目标化合物范围内,容易逃脱标准监管范围。