细胞凋亡及相关基因联合检测对胃黏膜癌前病变的诊断及癌变预测的意义

目的 探讨细胞凋亡及相关基因的表达在胃黏膜癌变中的作用及对胃癌的预测和早期诊断的意义.方法 对胃镜活检确诊为胃癌(胃癌组)及不典型增生(分为轻、中、重度不典型增生组)的标本应用TUNEL法检测细胞凋亡,应用免疫组化法检测p16、bcl-2、ras、c-myc、p53基因的表达.结果 p16、bcl-2、ras、c-myc和p53基因表达率在轻、中、重度不典型增生组和胃癌组分别为69.23%,30.77%,38.46%,23.08%,7.69%;50.00%,37.50%,81.25%,43.75%,18.75%;36.36%,63.64%,81.82%,72.73%,45.45%;27.50%,67.50%,95.00%,90.00%,60.00%.轻度不典型增生组与胃癌组比较,差异有统计学意义(P＜0.05);ras、c-myc和p53基因表达率轻度不典型增生组与重度不典型增生组比较,差异有统计学意义(P＜0.05);p53与c-myc基因表达率中度不典型增生组与胃癌组比较,差异有统计学意义(P＜0.05).p16、bcl-2、ras、c-myc和p53基因表达存在相关性.细胞凋亡指数胃癌组最低,轻、中度不典型增生组与胃癌组比较,差异均有统计学意义(P＜0.01).轻度不典型增生组与重度不典型增生组比较,差异也有统计学意义(P＜0.01).结论 细胞凋亡指数减少及ras、bcl-2、c-myc、p16、p53基因的异常表达在胃黏膜癌变过程中发挥重要作用.中、重度不典型增生为重要的癌前病变.     

镉诱导LLC-PK_1细胞凋亡与bcl-2、p53蛋白表达关系的研究

目的　探讨镉诱导LLC PK1 细胞凋亡及与bcl 2、p5 3(mtp5 3)蛋白表达的相互关系。方法　采用透射电镜观察凋亡小体、流式细胞仪分析凋亡率、琼脂糖凝胶DNA电泳方法确定镉对LLC PK1 细胞诱导的凋亡作用 ,以及流式细胞仪分别测定bcl 2和p5 3基因表达产物bcl 2蛋白、mtp5 3蛋白。结果　透射电镜观察发现 4 0 μmol LCdCl2 作用LLC PK1 细胞 12h后 ,出现典型的凋亡小体 ;流式细胞仪分析其凋亡率为 32 6 1% ,并高于对照组 (1 0 8% ) (P <0 0 1) ;琼脂糖凝胶DNA电泳呈明显梯形条带。 0、10、2 0、4 0 μmol LCdCl2 作用LLC PK1 细胞 4h、8h ,8h后 ,bcl 2基因表达逐渐下降 ,并呈良好的剂量 -反应关系 (r=- 0 910 ,P <0 0 5 ) ;作用 4h、8h后mtp5 3蛋白表达均明显下降 ,并有剂量 -反应关系 (r值分别为 - 0 716、- 0 972 ,P值均 <0 0 5 )。结论　镉诱导LLC PK1 细胞凋亡可能与镉抑制bcl 2、mtp5 3蛋白表达有关     

丙型肝炎病毒非结构蛋白4B对肝癌细胞c—myc和p53蛋白表达的影响

目的 探讨丙型肝炎病毒非结构蛋白4B（HCV-NS4B）对c-myc和p53蛋白在肝癌细胞表达的影响.方法 采用构建好的HCV-NS4B表达载体,以脂质体转染法转染HepG2细胞.逆转录-聚合酶链反应（RT-PCR）,琼脂糖凝胶电泳证实HCV-NS4B在HepG2细胞稳定表达.随后采用细胞免疫化学法半定量分析c-myc和p53蛋白在HepG2细胞的表达.结果 转染HCV-NS4B后,NS4B转染组c-myc平均光密度值为0.53±0.17,较空白对照组及空白载体组显著升高（P＜0.05）.NS4B转染组p53蛋白平均光密度值为0.28 ±0.13,较空白对照组及空白载体组显著下降（P＜0.05）.结论 HCV-NS4B可诱导肝癌细胞中c-myc/p53失衡,促进细胞增殖,与肝癌发生有关.     

细胞凋亡及相关基因联合检测对胃黏膜癌前病变的诊断及癌变预测的意义

目的探讨细胞凋亡及相关基因的表达在胃黏膜癌变中的作用及对胃癌的预测和早期诊断的意义。方法对胃镜活检确诊为胃癌（胃癌组）及不典型增生（分为轻、中、重度不典型增生组）的标本应用TUNEL法检测细胞凋亡，应用免疫组化法检测p16、bcl-2、raa、c—myc、p53基因的表达。结果p16、bcl-2、ras、c-myc和p53基因表达率在轻、中、重度不典型增生组和胃癌组分别为69．23％，30．77％，38．46％，23．08％，7．69％；50．00％，37．50％，81．25％，43．75％，18．75％：36．36％．63．64％．81．82％．72．73％，45．45％：27．50％，67．50％，95．00％。90．00％，60．00％。轻度不典型增生组与胃癌组比较，差异有统计学意义（P〈0．05）；ras、c—myc和p53基因表达率轻度不典型增生组与重度不典型增生组比较，差异有统计学意义（P〈0．05）；p53与c—myc基因表达率中度不典型增生组与胃癌组比较，差异有统计学意义（P〈0．05）。p16、bcl-2、ras、c—myc和p53基因表达存在相关性。细胞凋亡指数胃癌组最低，轻、中度不典型增生组与胃癌组比较，差异均有统计学意义（P〈0．01）。轻度不典型增生组与重度不典型增生组比较，差异也有统计学意义（P〈0．01）。结论细胞凋亡指数减少及ras、bcl-2、c—myc、p16、p53基因的异常表达在胃黏膜癌变过程中发挥重要作用。中、重度不典型增生为重要的癌前病变。     

硒对镉诱导大鼠肝细胞端粒酶活力作用研究

目的 研究硒对镉诱导的大鼠肝细胞端粒酶活力、癌基因c-myc和p53表达的影响.方法 80只雄性SD大鼠随机分为16组,包括对照组,2.5、5.0和10.0 μmol/kg亚硒酸钠组,5.0、10.0和20.0μmol/kg氯化镉组,9个硒镉联合作用组.氯化镉采用腹腔注射染毒、亚硒酸钠采用灌胃染毒.用端粒重复序列扩增法(TRAP)检测端粒酶活力,用逆转录聚合酶链反应法检测c-myc和p53表达.结果 3个镉单独作用组的大鼠肝细胞端粒酶活力、c-myc和p53表达较对照组明显增高,差异有统计学意义(P＜0.05).硒镉联合作用组中,当2.5和5.0μmol/kg亚硒酸钠分别与5.0、10.0和20.0μmol/kg氯化镉联合作用时,大鼠肝细胞端粒酶活力、c-myc和p53 mRNA水平较相应剂量的镉单独作用组下降;当10.0 μmol/kg亚硒酸钠分别与5.0、10.0和20.0 μmol/kg氯化镉联合作用时,大鼠肝细胞端粒酶活力、c-myc和53 mRNA水平与相应剂量的镉单独作用组比较,差异无统计学意义(P＞0.05).结论 相对较低剂量的硒对镉引起的大鼠肝细胞端粒酶活力增高具有抑制作用,其抑制作用可能是通过降低c-myc和p53表达.     

CYP1A2基因在三氯乙烯毒性中的作用研究

[目的]应用分子克隆技术,建立CYP1A2基因沉默细胞株和CYP1A2基因高表达细胞株,研究CYP1A2基因对三氯乙烯毒性的影响.[方法]将三氯乙烯分别染毒L02肝细胞、CYP1A2基因沉默细胞和CYP1A2基因高表达细胞,染毒剂量分别为0.25 mmol/L、0.50 mmol/L、1.00 mmol/L、2.00 mmol/L和4.00 mmol/L,以DMSO作为对照溶剂,染毒12 h,观察凋亡基因(Bcl-2、Caspase-3、Caspase-8、Caspase-9)和癌基因(c-fos、c-myc、k-ras、P53)表达水平.[结果]三氯乙烯染毒CYP1A2基因沉默细胞后,Bcl-2的mRNA表达水平高于对照组(P＜0.01),三氯乙烯部分剂量组凋亡基因Caspase-3、Caspase-8、Caspase-9和癌基因c-fos、c-myc表达水平低于对照组(P＜ 0.05或P＜0.01).三氯乙烯染毒CYP1A2基因高表达细胞后,Bcl-2的mRNA表达水平相比对照组下降(P＜0.01),Caspase-3、Caspase-8和Caspase-9 mRNA表达水平相比对照组升高(P＜0.01); CYP1A2高表达细胞中癌基因c-fos、c-myc、k-ras表达水平高于对照组(P＜0.01),P53表达水平低于对照组(P＜0.01).[结论]在体内代谢与CYP1A2存在密切关系,沉默CYP1A2基因可以减少三氯乙烯在肝细胞内代谢活化,导致三氯乙烯对凋亡基因和癌基因表达水平下降;三氯乙烯在CYP1A2基因高表达细胞中,表现出对凋亡基因和癌基因的促进表达作用.     

白藜芦醇对胃癌MGC-803细胞增殖抑制作用

目的 探讨白藜芦醇对人胃癌MGC-803细胞株细胞周期影响及其机制.方法 采用四甲基偶氮噻唑蓝(MTT)法和集落形成试验检测白藜芦醇对胃癌细胞的增殖抑制作用,流式细胞术检测细胞周期的改变,逆转录-聚合酶链式反应(RT-PCR)检测细胞凋亡抑制基因-2(bcl-2)、增殖基因c-myc的mRNA表达水平.结果 白藜芦醇可抑制胃癌细胞增殖和集落形成能力,低、高剂量组的抑制率分别为6.9%,17.6%和27.98%,63.39%,差异均有统计学意义(P＜0.05);白藜芦醇能使胃癌细胞周期阻滞于G_0/G_1期,明显下调胃癌细胞bcl-2、c-myc基因mRNA表达水平(P＜0.05);用药24 h后,白藜芦醇高剂量组bcl-2和c-myc基因相对表达量分别为(0.54±0.04),(0.58±0.05),与空白对照组(0.91±0.05),(0.85±0.03)比较,差异均有统计学意义(P＜0.05).结论 白藜芦醇可抑制胃癌MGC-803细胞增殖并使其细胞周期阻滞于G_0/G_1期,可能与下调bcl-2、c-myc基因表达有关.     

慈菇对镉致肝脏脂质过氧化及c-fos mRNA表达的影响

目的 探讨慈菇对镉致肝脏脂质过氧化及c-fos mRNA表达的影响。方法 36只雄性SD大鼠随机分为6组（n＝6），分别用25％、50％、75％ 慈菇（2ml/100g体重），维生素E（50mg/100g体重）及等体积馏水灌胃，连续10d，末次灌胃24h后，腹腔注射CdcL2(20μmol/kg体重），染毒24h后，比较各组肝脏丙二醛（MDA）、谷胱甘肽（GSH）含量及谷胱甘肽过氧化物酶（GSH－PX）活性；并利用反转录聚合酶链式反应（RT－PCR）对肝脏c-fos mRNA进行半定量测定。结果 VE和中、高剂量慈菇都降低了镉所升高的MDA含量（P＜0.05），中、高剂量的慈菇还提高了氯化镉所降低的肝脏GSH含量（P＜0.05）；而VE和各剂量慈菇都不能纠正氯化镉所升高的c-fos mRNA水平（P＞0.05）。结论 镉对肝脏c-fos mRNA表达的诱导不是或仅小部分由脂质过氧化所介导。     

CYP1A2基因沉默及其对三氯乙烯毒性影响

目的 构建细胞色素氧化酶1A2(CYP1A2)基因沉默载体,转染L02人正常肝细胞(简称“L02细胞”),建立CYP1A2沉默细胞株并观察其对三氯乙烯(TCE)毒性的影响.方法 设计合成短发卡RNA(shRNA),连接到pLKO.1-puro质粒中构建CYP1 A2 shRNA慢病毒表达载体,感染L02细胞.筛选CYP1A2沉默细胞株,采用荧光定量聚合酶链式反应和免疫印迹法鉴定.分别采用浓度为0.25、0.50、1.00、2.00和4.00 mmol/L的TCE(设为相应的染毒剂量组)对L02细胞和CYP1A2沉默细胞染毒12h,同时设置二甲基亚砜溶剂对照组(即0.00 mmoL/L染毒剂量组),观察凋亡基因[B淋巴细胞瘤-2基因(Bcl-2)、天冬氨酸特异性半胱氨酸蛋白酶(Caspase)-3、Caspase-8、Caspase-9]和癌基因(c-fos、c-myc、K-ras、p53)等基因表达的变化.结果 测序证明插入pLKO.1-puro载体的CYP1A2基因干扰序列与设计的shRNA 序列一致.CYP1A2沉默细胞的CYP1A2mRNA和CYP1A2蛋白相对表达水平分别较L02细胞下降75.9％和82.4％(P＜0.01).TCE染毒后,0.25 ～4.00 mmol/L 4个染毒剂量组CYP1A2沉默细胞Bcl-2表达水平均高于相应染毒剂量组L02细胞(P＜0.01);部分0.25 ～4.00 mmol/L染毒剂量组Caspase-3、Caspase-8、Caspase-9和c-fos、c-myc k-ras、p53相对表达水平均低于相应染毒剂量组的L02细胞(P＜0.05或P＜0.01).结论 CYP1A2沉默降低TCE对L02细胞凋亡基因和癌基因的活化作用.     

醋酸铅对大鼠脑细胞凋亡及bcl-2、bax基因表达的影响

目的：探讨醋酸铅对大鼠脑细胞凋亡的诱发作用及对bcl-2,bax基因表达的影响。方法：24只SD大鼠腹腔注射醋酸铅5d,剂量分别为25,50,100mg/kg体重,第6天取其大脑皮层,海马,小脑组织,用流式细胞仪分别测定其细胞凋亡率和bcl-2 bax基因的表达产物Bcl-2蛋白,Bax蛋白。结果：各染铅组大鼠皮层,海马,小脑细胞亡率明显升高,与对照组相比差异具有显著性,并具有良好的剂量－反应关系;bcl-2基因表达（FI指数）明显降低,而bax基因表达则明显增加,与对照组相比差异均具有显著性（P＜0．01）,并具有良好的剂量－反应关系,Bcl-2/Bax明显下降,与对照组相比差异具有显著性,并具有良好的剂量－反应关系,相关分析表明,大鼠大脑皮层,海马和小脑细胞凋亡率与Bcl-2含量呈负相关,而与Bax含量正相关,与Bcl-2/Bax呈负相关。结论：铅可以诱发大鼠脑细胞凋亡,其机制可能与脑组织内bcl-2基因表达下调,bax基因表达上调以及Bcl-2/Bax下降有关。     

Risk,Efficacy, and Seeking of General,Breast, and Prostate Cancer Information

The authors investigated the independent and interactive effects of perceived risk and perceived efficacy on seeking of general, breast, and prostate cancer information. Analysis of the 2003 Health Information National Trend Survey indicates that perceived absolute risk and perceived response efficacy have generally independent—rather than interactive—effects on cancer information seeking. The influence of perceived absolute risk on prostate cancer information seeking appears to be moderated by perceived relative risk. When perceived relative risk is low, perceived absolute risk has no effect on prostate cancer information seeking; when perceived relative risk is high, perceived absolute risk exerts a significant positive influence on prostate cancer information seeking. The authors discuss the theoretical and practical implications.     

Water,sanitation, and hygiene in schools: Status and implications of low coverage in Ethiopia,Kenya, Mozambique,Rwanda, Uganda,and Zambia

Adequate access to water, sanitation, and hygiene (WaSH) in schools impacts health, educational outcomes, and gender disparities. Little multi-country research has been published on WaSH in rural schools in Sub-Saharan Africa. In this multi-national cross-sectional WaSH study, we document WaSH access, continuity, quality, quantity, and reliability in 2270 schools that were randomly sampled in rural regions of six Sub-Saharan African countries: Ethiopia, Kenya, Mozambique, Rwanda, Uganda, and Zambia. Data collection included: school WaSH surveys containing internationally established WaSH indicators, direct observation, and field- and laboratory-based microbiological water quality testing. We found 1% of rural schools in Ethiopia and Mozambique to 23% of rural schools in Rwanda had improved water sources on premises, improved sanitation, and water and soap for handwashing. Fewer than 23% of rural schools in the six countries studied met the World Health Organization’s recommended student-to-latrine ratios for boys and for girls. Fewer than 20% were observed to have at least four of five recommended menstrual hygiene services (separate-sex latrines with doors and locks, water for use, waste bin). The low access to safe and adequate WaSH services in rural schools suggest opportunities for WaSH interventions that could have substantive impact on health, education, and gender disparities.     

Bioaccumulation,metabolism, and effects of DDT,fenitrothion, and chlorpyrifos onSaccharomyces cerevisiae

Saccharomyces cerevisiae accumulated DDT, fenitrothion, and chlorpyrifos rapidly from yeast glucose medium. The maximum concentrations of DDT, fenitrothion, and chlorpyrifos accumulated were 8,253, 18,960 and 11,579 g/g (dry wt), respectively. The pattern of accumulation was similar for all insecticides. The bioconcentration factor was inversely proportional to insecticide solubilities.Saccharomyces metabolized the three insecticides, but only two metabolites of DDT (DDD and DDE) were identified. Protoplast cultures were more sensitive to DDT and fenitrothion compared to normal cultures but were less sensitive to chlorpyrifos. Both the normal and protoplast cultures recovered from the toxic effect after 24 hr.     

Risk, efficacy, and seeking of general, breast, and prostate cancer information

The authors investigated the independent and interactive effects of perceived risk and perceived efficacy on seeking of general, breast, and prostate cancer information. Analysis of the 2003 Health Information National Trend Survey indicates that perceived absolute risk and perceived response efficacy have generally independent-rather than interactive-effects on cancer information seeking. The influence of perceived absolute risk on prostate cancer information seeking appears to be moderated by perceived relative risk. When perceived relative risk is low, perceived absolute risk has no effect on prostate cancer information seeking; when perceived relative risk is high, perceived absolute risk exerts a significant positive influence on prostate cancer information seeking. The authors discuss the theoretical and practical implications.     

Analysis of protein amino acids,non-protein amino acids and metabolites,dietary protein,glucose, fructose,sucrose, phenolic,and flavonoid content and antioxidative properties of potato tubers,peels, and cortexes (pulps)

The composition and antioxidative activity of whole potato tubers from five Korean cultivars, three peels from one cultivar, and eight pulps (cortexes) after peeling from six different cultivars were evaluated. Whole tubers were sectioned into three parts followed by analysis of the peels and pulps of each part. The following characteristics were determined: the dimensions and water content of whole tubers; nutritional protein content consisting of protein and free amino acids by an automated Kjeldahl nitrogen assay; free non-protein amino acids, metabolites, and fructose, glucose, and sucrose content by HPLC; phenolic compounds by HPLC and LC/MS; total phenolics and flavonoids by colorimetry; and antioxidative properties by ABTS, DPPH, and FRAP assays. The results demonstrate differences and similarities in the content of nutritional and bioactive compounds and in their bioactivities from whole potatoes, peels, and pulps. The present study reports for the first time the analysis of multiple potato nutrients and bioactive components as well the antioxidative properties of whole potatoes, peels, and pulps derived from the same tubers. The described methods are expected to facilitate the analysis of commercial and newly-developed potato cultivars, peels, and pulps and relate their composition and antioxidative activities to their reported nutritional, health-promoting, and industrial properties.     

The effect of lead and cadmium on liver,kidney, and brain levels of cadmium,copper, lead,manganese, and zinc,and on erythrocyte ALA-D activity in mice

Summary Lead and cadmium were administered intraperitoneally, singly and jointly, to the mice. The levels of cadmium, copper, manganese, lead and zinc were determined in liver, kidney and brain by atomic absorption spectrophotometric technique and deltaaminolevulinic acid dehydratase (ALA-D) activity was determined in erythrocytes. The tissue levels of some of these metals were found significantly altered by cadmium and lead both, but cadmium was found to have no effect on blood on ALA-D activity.     

Toxicity of mercury,copper, nickel,lead, and cobalt to embryos and larvae of zebrafish,Brachydanio rerio

The toxicity of mercury (HgCl₂), copper (CuCl₂: 5 H₂O), nickel (NiSO₄: 6 H₂O), lead (Pb(CH₃COO)₂: 3 H₂O) and cobalt (CoCl₂: 6 H₂O) was studied under standardized conditions in embryos and larvae of the zebrafish,Brachydanio rerio. Exposures were started at the blastula stage (2–4 h after spawning) and the effects on hatching and survival were monitored daily for 16 days. Copper and nickel were more specific inhibitors of hatching than cobalt, lead, and mercury. Nominal no effect concentrations determined from the dose-response relationships (ZEPs, Zero Equivalent Points) for effect on hatching time were 0.05 g Cu/L, 10 g Hg/L, 20 g Pb/L, 40 g Ni/L and 3,840 g Co/L, and those for effect on survival time were 0.25 g Cu/L, 1.2 g Hg/L, 30 g Pb/L, 80 g Ni/L, and 60 g Co/L. The no effect concentrations for Ni, Hg and Pb are consistent with previously reported MATC values for sensitive species of fish. The no effect concentrations for copper are 1–2 orders of magnitude lower than previously reported values. The major reason for the latter discrepancy was considered to be the absence of organics that can complex copper ions in the reconstituted water that we used, which had a hardness of 100 mg/L (as CaCO₃) and a pH of 7.5–7.7. Unexposed controls were started with embryos from different parental zebrafishes and the parental-caused variability in early embryo mortality, median hatching time and median survival time were estimated.