Analysis of cytotoxic effects of silver nanoclusters on human peripheral blood mononuclear cells ‘in vitro’

The antimicrobial properties of silver nanoparticles (AgNPs) have made these particles one of the most used nanomaterials in consumer products. Therefore, an understanding of the interactions (unwanted toxicity) between nanoparticles and human cells is of significant interest. The aim of this study was to assess the in vitro cytotoxicity effects of silver nanoclusters (AgNC, < 2 nm diameter) on peripheral blood mononuclear cells (PBMC). Using flow cytometry and comet assay methods, we demonstrate that exposure of PBMC to AgNC induced intracellular reactive oxygen species (ROS) generation, DNA damage and apoptosis at 3, 6 and 12 h, with a dose‐dependent response (0.1, 1, 3, 5 and 30 µg ml^–1). Advanced electron microscopy imaging of complete and ultrathin‐sections of PBMC confirmed the cytotoxic effects and cell damage caused by AgNC. The present study showed that AgNC produced without coating agents induced significant cytotoxic effects on PBMC owing to their high aspect ratio and active surface area, even at much lower concentrations (<1 µg ml^–1) than those applied in previous studies, resembling what would occur under real exposure conditions to nanosilver‐functionalized consumer products. Copyright © 2015 John Wiley & Sons, Ltd.     

Flow cytometry evaluation of in vitro cellular necrosis and apoptosis induced by silver nanoparticles

Particles possess unique properties in the nanoscale, e.g., enhanced catalytic activity, high surface area, and light emission/absorption properties, that might result in interference with colorimetric in vitro cytotoxicity assays such as MTT, XTT or MTS. Alternatively, assays that do not use spectrophotometric detection, such as trypan blue exclusion or flow cytometry (FC) based assays, are less likely to be influenced by nanoparticle interference. The aim of this study was to evaluate FC assays to assess the cytotoxicity of three different sizes (10, 100, or 200 nm) of silver nanoparticles (AgNPs) at different mass concentrations (1, 25, or 50 ug/ml) in L-929 fibroblast cells. After 4 h and 24 h exposure, cell necrosis and apoptosis were assessed using 7-AAD and Annexin V dyes, respectively, with FC. The data indicate that cell necrosis and apoptosis in AgNP-exposed fibroblasts depends on dose, exposure time, and AgNP size. The data indicate that AgNPs produced a dose- and time-dependent decrease in cell viability; however, 10 nm AgNPs were significantly more toxic than larger-sized particles. Thus, standard FC assays can be utilized to assess apoptosis and necrosis in response to nanomaterial exposure.     

Potential of biofluid components to modify silver nanoparticle toxicity

Establishing realistic exposure scenarios is critical for cytotoxic investigation of silver nanoparticles (AgNP) in the gastrointestinal tract. This study investigated the potential interaction with and effect of biofluid components, namely cholic acid, deoxycholic acid and ursodeoxycholic acid, on AgNP toxicity. Two cell lines corresponding to organs related to the biofluid components were employed. These were HepG‐2 a hepatocellular carcinoma derived from liver tissue and Hep2 an epithelial cell line. Physiochemical and cytotoxic screening was performed and the ability of biofluid components to modify AgNP cytotoxicity was explored. No alteration to the physiochemical characteristics of AgNP by biofluid components was demonstrated. However, biofluid component addition resulted in alteration of AgNP toxicity. Greater reactive oxygen species induction was noted in the presence of cholic acid and deoxycholic acid. Ursodeoxycholic acid demonstrated no modification of toxicity in HepG‐2 cells; however, significant modification was noted in Hep2 cells. It is concluded that biofluid components can modify AgNP toxicity but this is dependent on the biofluid component itself and the location where it acts. Copyright © 2015 John Wiley & Sons, Ltd.     

Comparative toxicity of silicon dioxide,silver and iron oxide nanoparticles after repeated oral administration to rats

Although silicon dioxide (SiO₂), silver (Ag) and iron oxide (Fe₂O₃) nanoparticles are widely used in diverse applications from food to biomedicine, in vivo toxicities of these nanoparticles exposed via the oral route remain highly controversial. To examine the systemic toxicity of these nanoparticles, well‐dispersed nanoparticles were orally administered to Sprague–Dawley rats daily over a 13‐week period. Based on the results of an acute toxicity and a 14‐day repeated toxicity study, 975.9, 1030.5 and 1000 mg kg^–1 were selected as the highest dose of the SiO₂, Ag and Fe₂O₃ nanoparticles, respectively, for the 13‐week repeated oral toxicity study. The SiO₂ and Fe₂O₃ nanoparticles did not induce dose‐related changes in a number of parameters associated with the systemic toxicity up to 975.9 and 1000 mg kg^–1, respectively, whereas the Ag nanoparticles resulted in increases in serum alkaline phosphatase and calcium as well as lymphocyte infiltration in liver and kidney, raising the possibility of liver and kidney toxicity induced by the Ag nanoparticles. Compared with the SiO₂ and Fe₂O₃ nanoparticles showing no systemic distribution in all tissues tested, the Ag concentration in sampled blood and organs in the Ag nanoparticle‐treated group significantly increased with a positive and/or dose‐related trend, meaning that the systemic toxicity of the Ag nanoparticles, including liver and kidney toxicity, might be explained by extensive systemic distribution of Ag originating from the Ag nanoparticles. Our current results suggest that further study is required to identify that Ag detected outside the gastrointestinal tract were indeed a nanoparticle form or ionized form. Copyright © 2015 John Wiley & Sons, Ltd.     

采用不同方法检测幽门螺杆菌的感染情况

目的 探讨几种不同方法检测幽门螺杆菌感染的临床效果,分析幽门螺杆菌感染与性别、年龄及疾病的相关性.方法 选取2012年8月至2014年8月在我院消化科门诊就诊的806例患者,分别采用尿素呼气试验法,免疫胶体金法以及病理组织切片染色镜检进行检测,以尿素呼气试验法作为金标准,比较免疫胶体金法与病理组织切片染色镜检法检测Hp的阳性预期值、阴性预期值、敏感度、特异性并比较不同性别、不同年龄及不同疾病Hp的感染率.结果 Hp检出率为37.5％,其中男性感染率为37.3％,女性为37.7％,差异无统计学意义(P＞0.05);随着年龄增长Hp感染率有升高趋势,差异有统计学意义(P＜0.05);确诊为慢性胃炎、消化性溃疡、胃息肉、胃癌的Hp感染率分别为48.6％、50.2％、21.6％、13.8％,慢性胃病的发生与幽门螺杆菌感染有一定的关联.免疫胶体金法以及病理组织切片染色镜检的敏感度分别为83.77％、93.05％,特异性分别为75.20％、83.53％,阳性预期值分别为66.93％、77.20％,阴性预期值为分别为88.55％、95.25％.结论 胶体金法适用于大批量的流行病学调查,病理组织切片染色镜检敏感性高,可作为Hp感染筛查的方法之一.Hp感染率与年龄、疾病种类相关,与性别无关,为幽门螺杆菌感染的流行病学资料提供依据.     

淫羊藿组分缓释制剂的研究

筛选淫羊藿组分缓释片的处方,建立体外释放评价方程.采用胶态二氧化硅辅助喷雾干燥淫羊藿组分,并以其为主药制备缓释片.以主要成分宝藿苷Ⅰ的溶出度为评价指标考察骨架材料类型、填充剂、致孔剂、润滑剂等辅料对缓释片质量的影响,并采用干法压片工艺制备出淫羊藿组分缓释片.所筛选的缓释片处方为主药35％,羧甲基纤维素HPMC K4M20％和HPMC K15M10％为骨架材料,微晶纤维素31％,PEG6000 2％,硬脂酸镁2％.该处方条件下制备的淫羊藿组分缓释片体外持续8h释药达80％.零级方程、一级方程及Higuchi方程等都能较好模拟缓释片体外释放特征,其相关系数r均大于0.96.其中一级方程与体外释放特征最相似,其相关系数r为0.995 0.该制备方法操作简单,处方筛选结果真实可靠,可为淫羊藿组分缓释制剂的生产制备提供思路和方法指导.     

类鼻疽血清ICA诊断试纸的研制及初步应用

目的　研制免疫层析法类鼻疽血清诊断试纸 (ICA) ,用于检测哺乳动物血清中类鼻疽特异性抗体 ,从而诊断类鼻疽病。方法　采用柠檬酸三钠还原法制备胶体金颗粒 ,并标记上金黄色葡萄球菌蛋白A ;用类鼻疽多糖抗原致敏硝酸纤维素膜 ;最后组装成免疫层析检测条。用该检测条检测了 3份兔血清、16份猪血清、2 6份人血清标本。结论　我们所研制的类鼻疽血清ICA诊断试纸检测不同哺乳动物血清标本的结果与IHA结果与ELISA实验结果一致 ,具有较好的特异性和敏感性 ,并且更简便快速 ,适合基层单位使用。     

克银合剂治疗血热型白疕疗效及对肿瘤坏死因子-α的影响

目的 研究克银合剂治疗血热型白疕(寻常型银屑病)疗效及对肿瘤坏死因子-α(TNF-α)的影响.方法 选取30例寻常型银屑病血热型患者作为研究对象,进行克银合剂治疗,另选取同期接受健康体检的健康人30例作为对照组,研究克银合剂对TNF-α的影响.结果 治疗前TNF-α水平显著高于健康对照组,进行克银合剂治疗后患者症状、体征评分均显著低于治疗前,各项指标水平已经接近对照组.结论 克银合剂能改善寻常型银屑病血热型患者的临床症状,对TNF-α异常也有一定的改善作用.     

Metal-loaded Zeolite Remediation of Soils Contaminated with Pandrug-resistant Acinetobacter Baumannii

Due to the development of resistance to antimicrobial agents, bacterium Acinetobacter baumannii is nowadays a leading cause of nosocomial outbreaks. Clinically relevant A. baumannii outside hospital settings including natural soils affected by human waste represents a public-health risk for humans and animals. The aim of this study was to investigate the potential of metal-loaded zeolites to eliminate viable A. baumannii from artificially contaminated natural soils. A. baumannii isolate was subjected to the activity of natural zeolitised tuff (NZ) and Cu-modified (CuNZ) or Ag-modified zeolite (AgNZ) in wet, slightly acidic terra rossa and slightly alkaline red palaeosol. A. baumannii survived in terra rossa and red palaeosol supplemented with 1 wt% of NZ for seven days and four months, respectively. The addition of 1 wt% of CuNZ to terra rossa and red palaeosol shortened the survival of A. baumannii to three and 14 days, respectively. The addition of 0.1 wt% of AgNZ to both soils resulted in complete removal of viable A. baumannii within 1 h of contact, while the total native heterotrophic bacterial counts remained high. Since AgNZ is prepared with a simple modification of cost-effective and environmentally friendly natural zeolite, it is a promising material for the remediation of soils contaminated with pandrug-resistant A. baumannii.