刺儿菜提取物抗BEL-7402肿瘤细胞活性的研究

目的研究刺儿菜提取物对BEL-7402肿瘤细胞生长的抑制作用,观察提取物作用下肿瘤细胞的凋亡情况。方法利用MTT比色法测定提取物对BEL-7402肝癌细胞生长的抑制率;采用透射电镜观察法和TUNEL染色法研究了刺儿菜提取物诱导肝癌细胞凋亡。结果刺儿菜提取物10,20,40,80mg/L对肝癌细胞有明显的抑制作用,随提取物浓度的增加和培养时间的延长,抑制作用逐渐增强;对该提取液处理培养24,48,72,96h的细胞凋亡指数有显著差异。结论刺儿菜提取物对肿瘤细胞生长有抑制作用。     

苦参碱对肝癌细胞增殖抑制作用研究

目的在体外观察苦参碱对BEL-7402肝癌细胞增殖的影响。方法用含不同浓度（0～3.2mmol/L）苦参碱的培养液在体外培养BEL-7402细胞24h,通过MTT试验测定其对BEL-7402细胞增殖的影响作用。结果在上述使用浓度范围内,苦参碱对BEL-7402细胞增殖的抑制率为0～36.7%。结论苦参碱在体外可抑制BEL-7402细胞的增殖,且呈剂量依赖性。     

三氧化二砷联合化疗诱导肝癌HepG2细胞凋亡作用机制研究

目的探讨三氧化二砷（As2O3）联合化疗诱导肝癌HepG2细胞凋亡的作用机制。方法体外培养人肝癌HepG2细胞株，分别给予As2O3和顺铂单独或联合处理，用细胞免疫组化酶法检测Bax、Bcl-2、Fas蛋白的表达情况；采用流式细胞仪观察人肝癌HepG2细胞株的细胞周期变化，细胞DNA含量的分布，测定不同作用时间后端粒酶活性的变化情况。结果As2O3，组肝癌HepG2细胞的Bax和Fas基因的表达明显增加，Bcl-2基因的表达明显降低；在DNA直方图上可见在G1期细胞前凋亡细胞呈现典型特征性的亚二倍体凋亡峰，使S期细胞减少，将细胞生长周期阻滞于G2/M期，联合用药组比单独用药组作用明显增强。结论As2O3及联合化疗能诱导肝癌细胞凋亡，其主要机制与增强Bax、Fas的表达，下调Bcl-2的表达，将细胞生长周期阻滞于G2/M期，阻止细胞的有丝分裂，抑制端粒酶活性有关。     

白毛藤对人肝癌Bel7402细胞增殖抑制及凋亡作用

目的 探讨白毛藤体外对人肝癌Bel7402细胞增殖与凋亡的影响及其作用机制.方法 采用四甲基偶氮噻唑蓝(MTT)法和荧光显微镜观察白毛藤对人肝癌Bel7402细胞的增殖抑制作用和其诱导Bel7402细胞凋亡情况;用反转录-聚合酶链式反应(RT-PCR)检测survivin、bax基因表达量的变化.结果 随白毛藤浓度增加、作用时间延长,对人肝癌Bel7402细胞的增殖抑制作用均明显增强(P＜0.01);4,8,16 mg/mL白毛藤组人肝癌Bel7402细胞凋亡率分别为10.98%、17.02%、26.78%,均高于对照组6.18%(P＜0.01);作用48 h后,4,8,16 mg/mL白毛藤组人肝癌Bel7402细胞中survivin基因灰度比值分别为(0.43±0.01)、(0.38±0.02)、(0.29±0.01).均低于对照组(0.65±0.05),差异均有统计学意义(P＜0.01);4,8,16 mg/mL,白毛藤组人肝癌Bel7402细胞中bax基因灰度比值分别为(0.47±0.05)、(0.56±0.04)、(0.73±0.06),均高于对照组(0.36±0.02),差异均有统计学意义(P＜0.01).结论 白毛藤可抑制人肝癌Bel7402细胞增殖、诱导其细胞凋亡,并能调控survivin及bax基因的表达.     

三氧化二砷联合化疗诱导肝癌HepG2细胞凋亡作用机制研究

目的探讨三氧化二砷(As2O3)联合化疗诱导肝癌HepG2细胞凋亡的作用机制。方法体外培养人肝癌HepG2细胞株,分别给予As2O3和顺铂单独或联合处理,用细胞免疫组化酶法检测Bax、Bcl-2、Fas蛋白的表达情况;采用流式细胞仪观察人肝癌HepG2细胞株的细胞周期变化,细胞DNA含量的分布,测定不同作用时间后端粒酶活性的变化情况。结果As2O3组肝癌HepG2细胞的Bax和Fas基因的表达明显增加,Bcl-2基因的表达明显降低;在DNA直方图上可见在G1期细胞前凋亡细胞呈现典型特征性的亚二倍体凋亡峰,使S期细胞减少,将细胞生长周期阻滞于G2/M期,联合用药组比单独用药组作用明显增强。结论As2O3及联合化疗能诱导肝癌细胞凋亡,其主要机制与增强Bax、Fas的表达,下调Bcl-2的表达,将细胞生长周期阻滞于G2/M期,阻止细胞的有丝分裂,抑制端粒酶活性有关。     

三氧化二砷联用华蟾素对K562细胞增殖和凋亡的影响

目的 研究三氧化二砷联用华蟾素对K562细胞增殖和凋亡的影响,为三氧化二砷和华蟾素联合应用于临床提供理论依据.方法 细胞增殖采用细胞生长及活力测定;细胞凋亡采用细胞形态、Annexin-V/PI双染实验、DNA的PI染色及DNA电泳等方法 测定.结果 在三氧化二砷和华蟾素作用下K562细胞生长受抑伴随活力下降,1.0 μmol/L As2O3、0.125μg/rnl华蟾素、0.25 μg/ml华蟾素、1.0 μmol/L As2O3＋0.125μg/ml华蟾素、1.0 μmol/L As2O3＋0.25μg/ml华蟾素作用K562细胞24 h和48 h后,增殖抑制率分别为（24±1.3）%、（21±1.5）%、（38±3.1）%、（57±2.7）%、（66±3.3）%及（49±2.9）%、（48±2.7）%、（61±2.1）%、（77±3.8）%、（82±4.2）%,细胞凋亡率分别为（4.8±0.5）%、（5.6±0.7）%、（9.8±0.6）%、（11.9±1.2）%、（15.2±1.5）%及（11.0±0.9）%、（12.9±1.1）%、（18.4±1.5）%、（21.0±2.0）%、（28.0±1.9）%,凋亡细胞百分率呈时间剂量依赖关系;基因组DNA电泳出现＂梯＂状条带.结论 三氧化二砷和华蟾素均有抑制K562细胞增殖和诱导该细胞凋亡的作用,两药联用效果更佳.     

As2O3对NB4细胞增殖及凋亡的影响

目的研究不同浓度的三氧化二砷（As2O3）对急性粒细胞白血病细胞株NB4（APLM3）凋亡及细胞周期的影响。方法采用四甲基偶氮噻唑蓝（MTT）法测As2O3对NB4的细胞毒活性，流式细胞仪AnnexinVFITC-PI检测细胞凋亡率，溴化丙碇（PI）染色法检测细胞周期。结果1～8μmol／LAs2O3能显著抑制NB4细胞增殖，且这些变化呈明显的时间和浓度依赖关系（时间一剂量效应）。2～8μmol／LAs2O3能显著诱导NIM细胞凋亡，处理时间为12h，其早期凋亡率和总凋亡率均与剂量呈线性正相关；处理时间为24h，其早期凋亡率、中晚期凋亡率和总凋亡率与剂量呈线性正相关；As2O3处理时间为36h和48hNB4细胞以中晚期调亡为主。流式细胞检测表明，不同浓度的As2O3均使NB4细胞周期阻滞在G2／M期。结论As2O3能抑制人白血病NB4细胞增殖，其作用机制可能是通过诱导细胞凋亡和抑制细胞增殖使细胞受阻于G2／M期。其诱导凋亡作用具有时间和浓度依赖关系。     

103Pd粒子联合加热41℃对人肝癌细胞7402细胞毒作用的实验研究

目的 研究^103Pd粒子与加热41℃对人肝癌细胞株(Bel-7402)的细胞毒作用，了解^103Pd粒子对热疗后残存的肝癌细胞的细胞毒作用。方法 以体外培养的人肝癌细胞-7402为研究对象，采用对照分组、水浴加温法、体外细胞毒试验(MTT)、凋亡实验(Hoechst33258荧光染色法)的方法以及方差分析，观察^103Pd粒子放疗联合加热41℃对Bel-7402细胞的生长抑制作用。结果 ^103Pd粒子对41℃加热后的人肝癌细胞-7402有明显的细胞抑制作用，强于单纯^103Pd粒子放疗。结论 人肝癌细胞-7402对^103Pd粒子放疗敏感，^103Pd粒子联合加热41℃有增效作用。提示：^103Pd粒子对热疗后残存的肝癌细胞有细胞毒作用。     

三氧化二砷对人肝癌多药耐药细胞Bel-7402作用相关机制的研究

目的研究As2O3诱导多药耐药人肝癌细胞Bel-7402/VCR凋亡及相关基因表达的情况。方法MTT法观察细胞生长和对VCR敏感性,应用形态学手段和流式细胞术检测细胞凋亡,应用免疫组织化学研究多药耐药相关基因表达的影响。结果As2O3对Bel-7402/VCR及Bel-7402细胞的生长抑制均呈明显的量效关系;Bel-7402/VCR及Bel-7402凋亡细胞百分比随着As2O3作用时间延长和作用浓度的增加明显增加;As2O3对Bel-7402/VCR及Bel-7402MDR1阳性表达率为81.6%和80.2%。结论As2O3在体外表现出较强的逆转肝癌多药耐药性作用。     

去蛋氨酸环境中多种化疗药对肝癌细胞株的杀伤作用

目的 探索肝癌细胞和肝细胞在缺乏蛋氨酸环境中的生长状况和去蛋氨酸状况与多种化疗药物联合应用是否可增加对肝癌细胞的杀伤作用。方法 将肝癌细胞株BEL-7402、肝细胞株L-02分别置于不含蛋氨酸含同型半胱氨酸培养基(Met^-Hcy^ )和含蛋氨酸不含同型半胱氨酸培养基(Met^ Hcy^-)中培养，MTT法检测两组细胞增值状态及在不同培养基中分别加入ADM、CDDP、5-FU、MMC和MTX化疗药物后，对各组细胞生长的抑制程度。结果 L-02在Met^-Hcy^ 和Met^ Hcy^-中生长无差异；Met^-Hcy^ 未增加5-FU、ADM、CDDP、MMC和MTX对L-02的毒性作用。与Met^ Hcy^-组相比，在Met^-Hcy^ 培养基中BEL-7402细胞生长受抑。Met^-Hcy^ 与5-FU相结合可显著提高对BEL-7402细胞的杀伤作用，与ADM、CDDP、MMC和MTX结合未提高对BEL-7402细胞的杀伤作用。结论 肝癌细胞BEL-7402细胞具有Met依赖性。Met^-Hey^ 与周期特异性化疗药物5-FU相结合可显著提高其对肝癌细胞BEL-7402的杀伤作用。     

Calcium intake in the elderly: validation of a dietary questionnaire

Epidemiological studies of calcium and osteoporosis have been hampered by the lack of a suitable tool for assessing calcium intake. This report describes a new frequency and amount questionnaire for measuring present and past calcium intake in the elderly. The validity of the questionnaire was tested against two commonly used standards of dietary assessment, five-day duplicate diets and seven-day weighed dietary inventories. The resulting correlation coefficients were, respectively, r = 0.76 and r = 0.69, while that for repeatability was r = 0.84. Furthermore, the questionnaire categorized subjects into thirds of the distribution of intake with almost no gross misclassification. It is suggested that the present findings may be extended to the majority of normal, healthy elderly subjects, implying wide application for the questionnaire in the assessment of calcium intake in the elderly.     

The occurrence of antimicrobial substances in toilet,sink and shower drainpipes of clinical units: A neglected source of antibiotic residues

Antibiotics represent one of the most important drug groups used in the management of bacterial infections in humans and animals. Due to the increasing problem of antibiotic resistance, assurance of the antibacterial effectiveness of these substances has moved into the focus of public health. The reduction in antibiotic residues in wastewater and the environment may play a decisive role in the development of increasing rates of antibiotic resistance. The present study examines the wastewater of 31 patient rooms of various German clinics for possible residues of antibiotics, as well as the wastewater of five private households as a reference.To the best of our knowledge, this study shows for the first time that in hospitals with high antibiotic consumption rates, residues of these drugs can be regularly detected in toilets, sink siphons and shower drains at concentrations ranging from 0.02?μg·L^?1 to a maximum of 79?mg·L^?1. After complete flushing of the wastewater siphons, antibiotics are no longer detectable, but after temporal stagnation, the concentration of the active substances in the water phases of respective siphons increases again, suggesting that antibiotics persist through the washing process in biofilms. This study demonstrates that clinical wastewater systems offer further possibilities for the optimization of antibiotic resistance surveillance.     

Self-reported health problems among Swedish miners one year after unemployment

Unemployment is considered to be a public health concern sincedeterioration in the health of the unemployed is often anticipated.However, for some groups, such as miners, unemployment mightimprove health due to a cessation of potentially harmful occupationalexposures. This study evaluates the health of 79 miners in oneSwedish iron-ore mine, and 226 age-matched controls from thegeneral population, during one year after the closure of themine. The participants received a questionnaire regarding medicalhistory and subjective symptoms at the beginning of the studyperiod, and after one year. Statistically significant negativeeffects on self-reported health attributable to unemploymentwere not found, although neuropsychiatric symptoms were morecommon among the unemployed miners. The miners reported a statisticallysignificant improvement in grip force (p=0.031). They had asignificantly higher prevalence of symptoms associated withmining related exposures when compared with the population controls;pain in the upper extremities [relative risk (RR)=2.27, 95%confidence interval (Cl)=1.44–3.59), back pain (RR=1.84;Cl=1.237–2.75), vasospastic disease of the fingers (RR=2.05;Cl=1.18–3.57) and obstructive respiratory symptoms (attacksof dyspnea and wheezing: RR=3.67; Cl=1.167–11.6).     

Excès de cas humains et animaux de tularémie en France au cours de l’hiver 2007–2008 : émergence ou phénomène isolé ?

Context

Tularemia is a zoonosis affecting humans and hares in France. We describe the results of surveillance in both species, in 2007 and 2008.

Methods

Human tularemia cases are mandatorily notifiable in France since 2003. In hares, surveillance relies on volunteer hunter associations in all districts of the country. Data from mandatory reports and volunteer surveillance in 2007/2008 were analyzed and compared with previous results.

Results

In 2007/2008, 144 cases were reported in humans and 117 cases in hares. This was a 100% increase compared to previous years. Human cases differed from those of previous years only by the frequency of contact with breeding animals. Human cases without any documented risk exposure were also more frequent.

Conclusion

An increase of tularemia cases occurred in 2007/2008 in both species. Complementary studies are needed to identify the species reservoir in France to understand the causes of this peak of cases.     

Occupational health hazards in mining: an overview

This review article outlines the physical, chemical, biological, ergonomic and psychosocial occupational health hazards of mining and associated metallurgical processes. Mining remains an important industrial sector in many parts of the world and although substantial progress has been made in the control of occupational health hazards, there remains room for further risk reduction. This applies particularly to traumatic injury hazards, ergonomic hazards and noise. Vigilance is also required to ensure exposures to coal dust and crystalline silica remain effectively controlled.     

Manufacture and use of nanomaterials: current status in the UK and global trends

This paper provides an overview of the production and use of nanomaterials (NMs), particularly in the UK. Currently, relatively few companies in the UK are identifiable as NM manufacturers, the main emphasis being the bulk markets in metals and metal oxides, and some niche markets such as carbon nanotubes and quantum dots. NM manufacturing in the UK does not reflect the global emphasis on fullerenes, nanotubes and fibres. Some assumptions have been made about the types of NM that are likely to be imported into the UK, which currently include fullerenes, modified fullerenes and other carbon-based NMs including nanotubes. Many university departments, spin-offs and private companies have developed processes for the manufacture of NMs but may only be producing small quantities for research and development (R&D) purposes. However, some have the potential to scale up to produce large quantities. The nanotechnology industry in the UK has strong R&D backup from universities and related institutions. This review has covered R&D trends at such institutions, and appropriate information has been added to a searchable database. While several companies are including NMs in their products, only a few (e.g. manufacturers of paints, coatings, cosmetics, catalysts, polymer composites) are using nanoparticles (NPs) in any significant quantities. However, this situation is likely to change rapidly. There is a need to collect more information about exposure to NPs in both manufacturing and user scenarios. As the market grows, and as manufacturers switch from the micro- to the nanoscale, the potential for exposure will increase. More research is required to quantify any risks to workers and consumers.     

深圳公立医院管理体制改革制度设计

深圳公立医院管理体制改革实行政事分开、管办分开,在理事会架构下按法定机构模式组建市医管中心,落实公立医院运营管理自主权.作者从当前公立医院管理体制的弊端入手,介绍了深圳市进行公立医院管理体制改革的基本思路及改革方案设计的主要举措,深入剖析了的改革方案的特点,并对改革效果进行了预测.     

Effects of nitrogen dioxide on red blood cells of rats: Changes in components of red cell membranes during in vivo exposure to NO2

Red cell membranes, prepared from red blood cells of rats exposed to 4, 10, or 20 ppm nitrogen dioxide (NO₂) for 1 to 10 days, were examined for evidence of changes in membrane components. Appreciable changes were not found in contents of phospholipid and cholesterol during exposure to 10 ppm NO₂. By contrast, protein content altered with the time of exposure. Moreover, changes in protein composition were observed by employing sodium dodecyl sulfate — polyacrylamide gel electrophoresis. Twenty-four-hour exposure to NO₂ at the concentration above 10 ppm resulted in a marked increase in the percentage of lysophosphatidylethanolamine (LysoPE) to the total phospholipids. The prolonged exposure to 10 ppm NO₂ gave rise to a further increase in LysoPE, whereas the percentage of phosphatidylethanolamine (PE) showed a gradual decrease. A 1-day exposure to 4.0 ppm NO₂ also caused an increase in sialic acid content and decreases in those of PE and hexose. In addition to contents of these components the percentage of LysoPE increased 5 days after exposure and the elevated values were maintained up to the end of exposure period. These results demonstrate that red blood cells in circulation exhibit different membrane properties in terms of lipid and carbohydrate composition during 10 days of exposure to 4.0 ppm NO₂.     

Investigating clusters in the workplace and beyond

Clusters of disease are common and occur in the workplace and in the general community. They often arouse considerable concern among the population. Investigations have sometimes lead to exciting new knowledge, but in general the investigation of clusters is difficult and often unrewarding, especially for community clusters. In the workplace, investigations are more likely to find associations and even new causes, but still many clusters remain enigmatic. Despite this, there are many reasons for investigating clusters, including allaying community concern and identifying uncontrolled exposures. A structure for investigating clusters in the workplace is suggested.