Acute Effects of Inorganic Nitrate Intake on Brachial and Femoral Flow-Mediated Vasodilation,and on Carotid Artery Reactivity Responses: Results of a Randomized,Double-Blinded,Placebo-Controlled Cross-Over Study in Abdominally Obese Men

Most trials on the effects of inorganic nitrate intake have focused on only one specific aspect of the endothelial cell response to a stimulus, thereby possibly missing other important effects. The aim of the present randomized, double-blinded, placebo-controlled cross-over study was therefore to investigate in eighteen healthy abdominally obese men (18–60 years, waist circumference ≥ 102 cm) acute effects of potassium nitrate on brachial and femoral flow-mediated vasodilation (FMD), and on carotid artery reactivity (CAR) to a cold pressure test. Participants received in random order a drink providing 10 mmol potassium nitrate (i.e., 625 mg of nitrate) or an iso-molar placebo drink with potassium chloride. Fasted and 4 h post-drink FMD and blood pressure measurements were performed. CAR responses were assessed at 4 h. Circulating nitrate plus nitrite concentration increased following nitrate intake (p = 0.003). Compared with placebo, potassium nitrate did not affect brachial (mean [95% confidence interval]: −0.2% [−2.5, 2.1], p = 0.86) and femoral FMD responses (−0.6% [−3.0; 1.7], p = 0.54). CAR responses were also not different (−0.8% [−2.5, 0.9], p = 0.32). Finally, changes in blood pressure and heart rate did not differ. No adverse events were observed. In conclusion, this trial did not provide evidence for effects of a single dose of inorganic nitrate on 4 h vascular endothelial function in abdominally obese men.     

新疆伊犁哈族食管癌高发区饮用水三氮含量分析

目的 探讨新疆伊犁哈萨克族食管癌高发区新源县居民饮用水中氨氮、亚硝酸盐氮和硝酸盐氮含量与伊犁地区哈萨克族食管癌高发的关系,为新疆哈萨克族食管癌的防治工作提供科学依据。方法 采集伊犁地区哈萨克族食管癌高发区新源县和相对低发区巩留县的居民饮用水各60份,按照国家标准方法,采用紫外可见分光光度计对饮用水中氨氮、亚硝酸盐氮和硝酸盐氮含量进行检测。结果 新疆新源县居民饮用水河水氨氮、亚硝酸盐氮和硝酸盐氮含量分别为0.549、0.038、15.633 mg/L,均高于巩留县的0.359、0.029、10.786 mg/L,差异均有统计学意义（P<0.05）,且氨氮和硝酸盐氮含量超标;新源县和巩留县饮用水中“三氮”含量均在夏、秋两季相对较高,新源县饮用水中氨氮在四季的含量分别为0.224、0.473、0.328、0.105 mg/L,巩留县分别为0.187、0.310、0.203、0.111 mg/L;新源县饮用水中亚硝酸盐氮在四季的含量分别为0.018、0.031、0.024、0.013 mg/L,巩留县分别为0.015、0.021、0.020、0.018 mg/L;新源县饮用水中硝酸盐氮在四季的含量分别为8.436、14.152、9.547、7.542 mg/L,巩留县分别为7.753、10.260、7.953、5.466 mg/L。结论 新疆伊犁哈萨克族食管癌高发区新源县饮用水中较高的“三氮”含量,可能与新疆伊犁哈萨克族食管癌高发有关。     

Combined Influence of Lithium Nitrate and Metakaolin on the Reaction of Aggregate with Alkalis

The best known and effective methods for the reduction of the negative effects of an alkali–silica reaction in concrete include the application of mineral additives with an increased aluminium content and reduced share of calcium, as well as chemical admixtures in the form of lithium compounds. Because both aluminium and lithium ions increase the stability of reactive silica in the system with alkalis, it is possible to presume that the application of both corrosion inhibitors together will provide a synergistic effect in the ASR limitation. The paper presents the results of studies on the influence of combined application of metakaolin and lithium nitrate on the course of corrosion caused by the reaction of opal aggregate with alkalis. The potential synergistic effect was studied for the recommended amount of lithium nitrate, i.e., the Li/(Na + K) = 0.74 molar ratio and 5%, 10%, 15%, and 20% of cement mass replacements with metakaolin. The effectiveness of the applied solution was studied by measurements of mortars expansion in an accelerated test, by microstructure observations, and by determination of the ASR gels composition by means of SEM-EDS. The influence of metakaolin and the chemical admixture on the compressive and flexural strengths of mortars after 28 and 90 days of hardening were also analysed. The results of the studies revealed a synergistic effect for mixtures containing metakaolin at 15% and 20% cement replacement and lithium nitrate admixture in alkali–silica reaction expansion tests. It was found that corrosion processes in mortars with 5 and 10% levels of metakaolin became more severe after adding a lithium admixture to mortars with metakaolin only. The obtained results were confirmed by observations of the mortars’ microstructures. There was no synergistic impact of lithium nitrate and metakaolin on compressive strength characteristics. The compressive strength of mortars containing a combination of metakaolin and lithium nitrate decreased both after 28 and after 90 days, compared to mortars with metakaolin alone.     

表面活性剂在硝酸士的宁注射液酸性染料比色法中的应用

表面活性剂在光度分析中已经有了广泛的应用,不论是在水溶液中测定的胶束增溶光度法还是在有机溶剂中测定的胶束萃取光度法中,表面活性剂的加入都具有明显的增溶、增敏和增稳作用,它能直接影响显色反应的速度、平衡位置以及配合物的构型,能改变溶剂的     

离子敏感型毛果芸香碱眼用原位凝胶的制备及其初步药效学考察

目的 以海藻酸钠为胶凝剂,羟丙基甲基纤维素(HPMC)为增黏剂,制备硝酸毛果芸香碱(PN)眼用原位凝胶,以增强其疗效,减少给药次数.方法 通过对海藻酸钠与HPMC的配比研究,筛选出最佳的凝胶基质,制备PN原位凝胶;以PN滴眼剂及空白凝胶为对照,以家兔瞳孔直径为评定指标,进行初步药效学考察.结果 筛选出的最佳基质组成为:1%(w/v)海藻酸钠,2%(w/v)HPMC(E50LV).与PN滴眼液相比,PN原位凝胶缩瞳作用明显延长,具有缓释效果.结论 以海藻酸钠与HPMC制备的原位凝胶PN制剂具有缓释、长效作用,值得进一步研发.     

HPLC测定硝酸舍他康唑尿素乳膏中硝酸舍他康唑的含量

目的 建立高效液相色谱法测定硝酸舍他康唑尿素乳膏中硝酸舍他康唑的含量。方法 色谱柱：Hypersil C₁₈(4.6 mm×250 mm,5 μm);流动相：乙腈-0.01 mol·L^-1磷酸氢二钠溶液(用稀磷酸调pH=7.0)(37∶63);流速：1.0 mL·min^-1;检测波长：260 nm。结果 硝酸舍他康唑在20.4~102.0 μg·mL^-1内线性关系良好(r=0.999 3),平均回收率为99.55%,RSD=0.73%(n=6)。结论 此法操作简便、结果准确、精密度好,可用于硝酸舍他康唑尿素乳膏的质量控制。     

差异显示法的建立及其在辐射致癌机理研究中的初步应用

本研究目的建立差异显示技术,将基应用于辐诱发肺癌发生相关基因研究中。聚ＳＨＴＦ细胞（ＳＶ４０永生化人胎气管成纤维细胞）和αＳＨＴＦ细胞（α粒子照射后能在软琼脂上形成克隆的ＳＨＴＦ细胞）以及肺癌组织和同例正常肺组织为模板,将其ｍＲＮＡ进行ＲＴＰＣＲ扩增,采用放射自显影法和硝酸银染色法显示扩增片段,并比较两者的显示效果。结果表明：在细胞和组织样品中均建立了差异显示法,但硝酸银染色的条带较放射自显影显示     

泰安市售蔬菜中硝酸盐和亚硝酸盐含量的测定

<正> 蔬菜是易于富集硝酸盐的作物之一。White指出,人体摄取的硝酸盐81.2％来自蔬菜。Tremp认为,人体约有70％的硝酸盐是从蔬菜中摄取的。尽管硝酸盐本身对人体不具毒害性或毒害性较低,但它一旦被还原成亚硝酸盐之后,就有了潜在危险性。一方面亚硝酸盐易引起高铁血红蛋白症;另一方面它在适合的pH环境中,若有仲胺存在,就有可能发生     

硝酸亚铈对小鼠睾丸细胞酶活性和精子数量及质量的影响

目的探讨硝酸亚铈对于小鼠睾丸细胞酶活性和精子数量及质量的影响。方法100只雄性小鼠随机分为正常对照组、环磷酰胺组，硝酸亚铈15mg／kg、30,ng／kg、60mg／kg组，连续灌胃60d。采用酶化学方法检测乳酸脱氢酶（LDH）、山梨醇脱氢酶（SODH）、琥珀酸脱氢酶（SDH）、葡萄糖-6-磷酸脱氢酶（G-6-PD）的活性。显微镜下检测并计算小鼠的精子数量、活精率、活动度和畸形率。结果15mg／kg硝酸亚铈与环磷酰胺比较能促进LDH、SODH、SDH、G-6-PD的酶活性（P〈0．05），提升活精率和精子活动度（P〈0．05），降低精子畸形率（P〈0．05）。30mg／kg硝酸亚铈与环磷酰胺比较对SDH的活性有促进作用（P〈0．05），提升活精率和精子活动度（P〈0．05）。60mg／kg硝酸亚铈与正常对照比较对LDH、SDH、G-6-PD均有明显抑制作用（P〈0．05），降低精子数量、活精率、活动度（P〈0．05），增加畸形率（P〈0．05）。结论低剂量的硝酸亚铈可以通过促进小鼠睾丸细胞酶活性进而影响精子质量，而高剂量硝酸亚铈则对睾丸酶活性和精子数量及质量表现出明显的抑制作用。