Genotoxicity of marine sediments in the fish hepatoma cell line PLHC-1 as assessed by the Comet assay

The main goal of this study was to test the usefulness of the Comet assay in the PLHC-1 hepatoma fish cell line as a tool for detecting the presence of genotoxic compounds in contaminated marine sediments. The system has been tested using both model chemicals (benzo[a]pyrene (B[a]P) and ethyl methanesulfonate (EMS)) and extracts of sediment samples obtained with solvent dichloromethane/methanol. For all of the analysed sediment extracts as well as for the model chemicals a concentration dependent genotoxic effect was observed. The sediment with the highest observed genotoxic potential was additionally extracted using various solvents in order to test which class of compounds, according to their polarity, is most responsible for the observed genotoxic effect. Non-polar solvents (cyclohexane and dichloromethane) yielded stronger genotoxic effect but the highest level of DNA damage was determined after exposure to sediment extract obtained with the solvent mixture dichloromethane/methanol which extracts a wide range of contaminants. Our results indicate that the PLHC-1 cell line is a suitable in vitro model in sediment genotoxicity assessment and encourage the use of fish cell lines as versatile tools in ecogenotoxicology.     

Involvement of PI3K/Akt/CREB and redox changes in mitochondrial defect of osteoblastic MC3T3-E1 cells

Antimycin A (AMA) is an inhibitor of mitochondrial electron transport via its binding to complex III. In the present study, the mechanisms involved in AMA-induced cell damage were investigated. Treatment of osteoblastic MC3T3-E1 cells with AMA decreased adenosine 3′,5′-cyclic monophosphate (cAMP) level, activities of phosphoinositide 3-kinase (PI3K) and Akt (protein kinase B), and phosphorylated CREB (cAMP-response element-binding protein). To examine whether AMA-induced cell damage involves altered metabolism of pyridine nucleotides, the levels of NAD⁺, NADH, NADP⁺, and NADPH were measured. Treatment with AMA significantly decreased the levels of NAD⁺ and NADPH. Moreover, the activities of aconitase and thioredoxin reductase were decreased by AMA treatment. These results suggest that PI3K/Akt/CREB pathway and pyridine nucleotide (NAD⁺ and NADPH) are related to mitochondria function of osteoblasts.     

Preventive effect of chlorogenic acid on lens opacity and cytotoxicity in human lens epithelial cells

The present study reveals the pharmacological effect of chlorogenic acid, a major phenolic compound in plants, food, and coffee, on diabetic cataracts. Chlorogenic acid examined the inhibitory effects upon rat lens aldose reductase (AR) activity and xylose-induced rat lens opacity. The effect of chlorogenic acid on high glucose-induced cytotoxicity in lens epithelial cells was also examined. Chlorogenic acid showed potential inhibitory activity against rat lens AR, with an IC?? value of 0.95 μM. The xylose-induced opacity of lenses was significantly improved after treatment with chlorogenic acid in a dose-dependent manner. Chlorogenic acid prevented high glucose-induced cytotoxicity in human lens epithelial (HLE-B3) cells in a dose-dependent manner. These results suggest that chlorogenic acid may provide a potential therapeutic approach for prevention of diabetic complications, such as cataracts.     

某医学院校学生负担调查分析及对策研究

诠释了学生负担的内涵,以某医学院校为案例,调查分析了大学生负担的来源,讨论了减负的基本原则和对策。     

泛耐药鲍曼不动杆菌β-内酰胺类耐药机制研究

目的调查泛耐药鲍曼不动杆菌(pandrug-resistant Acinetobacter baumannii,PDR-ABA菌)临床分离菌株中β-内酰胺酶基因和膜孔蛋白基因的存在和变异情况。方法收集2010年3月到2010年5月临床标本中分离的PDR-ABA菌20株,采用微量肉汤烯释法进行抗菌药物敏感性试验,聚合酶链反应(PCR)和基因测序方法分析36种β-内酰胺酶基因和carO膜孔蛋白基因。结果本组20株PDR-ABA菌TEM-1、ADC-30-1ike、OXA-23型3种β-内酰胺酶基因全部阳性,CARB-2和DHA-1型阳性率为5.0%。在鲍曼不动杆菌中发现CARB-2型为国内首次报道。膜孔蛋carO基因突变率达100.0%。结论本组PDR-ABA菌对多种β-内酰胺类药物耐药与产TEM、ADC-30-like、OXA-23、CARB-2、DHA-1型5种13-内酰胺酶相关外,还与膜孔蛋白编码基因carO突变有关。     

High vancomycin minimum inhibitory concentration is a predictor of mortality in meticillin-resistant Staphylococcus aureus bacteraemia

Failure of vancomycin in the treatment of meticillin-resistant Staphylococcus aureus (MRSA) bacteraemia has been reported despite full susceptibility of the organism to vancomycin. A retrospective observational cohort study including 137 patients with MRSA bacteraemia was performed at two centres in South Korea during 2009-2010. A total of 137 patients with MRSA bacteraemia receiving vancomycin therapy were enrolled during the study period. Isolates from 13 (9.5%) of the 137 patients had minimum inhibitory concentrations (MICs) ≥1 μg/mL. The 30-day cumulative survival was 53.8% for patients infected with isolates having a MIC≥1 μg/mL and 79.8% for patients infected with isolates having a MIC<1 μg/mL (log-rank test, P=0.026). Vancomycin MIC≥1 μg/mL [hazard ratio (HR)=7.0, 95% confidence interval (CI) 2.2-22.1; P=0.001], nosocomial acquisition of bacteraemia (HR=5.4, 95% CI 1.4-20.1; P=0.013), rapidly fatal underlying diseases (HR=20.5, 95% CI 3.9-106.4; P<0.001), presentation with septic shock (HR=8.4, 95% CI 3.0-23.3; P<0.001), presence of complicated infections (HR=5.6, 95% CI 2.0-15.8; P=0.001) and persistent MRSA bacteraemia for ≥3 days (HR=4.2, 95% CI 1.4-12.7; P=0.012) were independent predictors of 30-day mortality in patients with MRSA bacteraemia. In patients with high Pitt bacteraemia scores (Pitt score ≥2), the delay in initiation of vancomycin therapy was significantly different between non-survivors and survivors (2.4 days vs. 1.1 days; P=0.012). Vancomycin MIC≥1 μg/mL had a significant impact on mortality of patients with MRSA bacteraemia. These findings support early consideration of alternative anti-MRSA agents in patients with MRSA bacteraemia who have high vancomycin MICs as well as prompt initiation of anti-MRSA treatment in patients with MRSA bacteraemia, especially those with high Pitt scores.     

RP-HPLC法测定硝酸毛果芸香碱滴眼液的有关物质

目的:建立反相高效液相色谱法测定硝酸毛果芸香碱滴眼液的有关物质。方法:采用色谱柱Shimadzu RP,C18柱(150 mm×4.6 mm,5μm);流动相为甲醇-含0.002 mol/L磷酸二氢铵和0.001 8 mol/L四丁基氢氧化铵的水溶液(30∶70),进行变流速梯度洗脱;检测波长为220 nm。结果:硝酸毛果芸香碱主成分峰与杂质峰的分离度均符合要求,硝酸毛果芸香碱的检出限为4 ng。结论:该方法简便、准确、灵敏度高,适用于硝酸毛果芸香碱滴眼液的有关物质分析。     

帕瑞昔布钠用于老年髋关节置换术后的镇痛效果和安全性

目的研究帕瑞昔布钠用于老年髋关节置换术后的镇痛效果和安全性。方法择期行全(半)髋关节置换术患者60例,ASAⅡ或Ⅲ级,随机分为帕瑞昔布钠组(P组)和对照组(C组),n=30。两组患者在给予硬膜外1mg吗啡负荷量后,P组术后应用2天帕瑞昔布钠40mg,每日2次,静脉注射,C组行硬膜外病人自控镇痛(PCEA,0.15%罗哌卡因+吗啡2mg共100ml,2ml/h)。记录术后48h内各时点的静息和运动VAS评分及疼痛补救措施,记录术后不良反应和生化指标变化,行术后24、48h患者总体满意度评价。结果 P组仅术后24h静息VAS评分高于C组(P<0.05),而其余时点与C组比较差异无统计学意义(P>0.05);P组术后12、18、24、28、36、48h时点运动VAS评分明显低于C组(P<0.05),且术后24、48h镇痛评价"非常好"比率明显优于C组(P<0.05),而术后瘙痒、恶心呕吐、心动过速、低血压、发热的发生率均低于C组(P<0.05)。结论髋关节置换术后静脉使用帕瑞昔布钠40mg,每日2次静脉注射,可以提供良好的镇痛效果,提高患者总体满意度,减少不良反应。     

IL-15 promotes osteoclastogenesis via the PLD pathway in rheumatoid arthritis

Osteoclastogenesis plays an important role in joint destruction in rheumatoid arthritis (RA). IL-15 is a pleiotropic proinflammatory cytokine that appears to help mediate the pathological bone loss. This study was undertaken to explore the signaling molecules essential for osteoclastogenesis mediated by IL-15 in rheumatoid synovial fibroblasts. Expression of phospholipase D1 (PLD1) and osteoclast-related gene expression in synovial tissues and their modulation by treatment with IL-15 and different inhibitors in synovial fibroblasts of RA patients were evaluated using immunohistochemistry and quantitative polymerase chain reaction. The levels of IL-15 in serum and synovial fluid were measured by ELISA. The effects of IL-15 and phosphatidic acid (PA) on osteoclast formation were evaluated in cocultures of rheumatoid synovial fibroblasts and peripheral blood monocytes or monocytes alone in the presence of M-CSF and RANKL. The levels of RANKL and PLD1 but not PLD2 were upregulated significantly by IL-15, and the RANKL level was significantly upregulated by PA in rheumatoid synovial fibroblasts. Blocking PA production with 1-butanol and siRNA against PLD1 significantly inhibited the IL-15-stimulated expression of RANKL and PLD1. IL-15 levels were significantly higher in serum and synovial fluid from patients with RA than in osteoarthritis patients and healthy controls. IL-15 and PA induced osteoclast formation through the mitogen-activated protein kinases (MAPKs) and NF-κB signaling pathways. Activation of PLD1 contributes to IL-15-mediated osteoclastogenesis via the MAPKs and NF-κB signaling pathways in rheumatoid synovial fibroblasts. Our data suggest that PLD1 might be an efficient therapeutic strategy for preventing bone destruction in rheumatoid arthritis.