清洗浸泡对虾皮亚硝酸盐含量的影响

目的了解不同清洗方式对虾皮中亚硝酸盐含量的影响。方法采用国标GB/5009.33-2010分光光度法,检测用去离子水和自来水清洗浸泡不同时间后虾皮中亚硝酸盐的含量。结果用去离子水及自来水浸泡虾皮0～30 min,随着浸泡时间的延长,均可使虾皮中亚硝酸盐含量显著降低(P0.01),之后浸泡40～90 min虽均可使亚硝酸盐含量有所波动,但相邻2组间差异亦无统计学意义。结论为了尽量减低虾皮中亚硝酸盐的含量,在烹饪之前最好应先浸泡再清洗,推荐浸泡30 min,再清洗2遍。     

短时静脉输注亚硝酸钠对心衰患者心肺血液动力学的影响

目的评估短时输注亚硝酸钠(Na NO2)对心衰患者血液动力学的影响。方法选择2014年1月至2015年2月在我院住院的25例严重慢性心衰患者,8例接受10μg/(kg·min)短时(5min)静脉输注NaNO_2,17例输注速度为50μg/(kg·min),并测量心脏的血液动力学。结果接受50μg/(kg·min)输注的患者,左室心搏量增加(P=0.003),肺血管阻力下降(P=0.03),右心房压降低(P=0.007),动脉血压轻度下降(P=0.04)。心搏量的增加与跨瓣膜梯度(肺毛细血管契压-右心房压)的增加相关(r=0.67,P=0.003)。接受10μg/(kg·min)的患者也出现相似的血液动力学改变,但差异无统计学意义。结论短时输注NaNO_2有益于失代偿HF患者的预后,为进一步评估其长效输注效果提供了安全保证。     

非离子氨和亚硝酸氮对虾虎鱼仔鱼的急性毒性及安全浓度评价

目的检测非离子氨和亚硝酸氮对鱼类的生态毒性效应。方法在水温(25±1)℃、溶氧(6.07～6.77)mg/L、盐度30～31、pH8.0～8.2的条件下,采用半静水式生物毒性试验方法研究了非离子氨和亚硝酸氮对裸项栉虾虎鱼(Ctenogobius gymnauchen)仔鱼的急性毒性效应(非离子氨浓度梯度设置为0、0.413、0.735、1.309、2.329、4.147 mg/L,亚硝酸氮浓度梯度设置为0、3.0、4.14、5.713、7.884、10.88 g/L)。结果非离子氨和亚硝酸氮暴露后仔鱼出现呆滞、侧游、呼吸困难、体色变白、身体弯曲等中毒症状,且随着暴露浓度的升高与暴露时间的延长,死亡率逐渐增加,存在明显的剂量效应关系和时间效应关系;非离子氨和亚硝酸氮对裸项栉虾虎鱼仔鱼96 hLC50分别为9.1 mg/L和12.405 g/L,其安全浓度分别为0.91 mg/L和1.2405 g/L。结论裸项栉虾虎鱼对非离子氨和亚硝酸氮具有较强的耐受力,非离子氨对裸项栉虾虎鱼仔鱼的毒性显著大于亚硝酸氮。     

高效液相色谱法测定常见药物中的亚硝酸盐含量

目的：探讨高效液相色谱法测定三种抗感染药物中的亚硝酸盐含量。方法：采用高效液相色谱法,通过优化色谱条件[流动相V（双蒸水）：V（乙腈）=60：40;检测波长：激发波长375nm,发射波长415nm;流速：0．8ml／min;进样量：lOμl;进样方式：自动式进样;柱温：50℃进行检测。结果：阿莫西林、头孢曲松钠、头孢唑肟钠三种样品的亚硝酸盐回收率在85．6％-95．5％之间,方法平均相对标准偏差在1．4％-2．6％之间,在0．0005-0．299μg／ml范围内线性关系良好,r=O．9999。结果：高效液相色谱法测定药物亚硝酸盐含量避免了传统方法中色素等有机物干扰严重的问题,方法简单,环境影响因素少,抗干扰能力强,值得推广应用。     

恩平市一起家庭卤制食品亚硝酸盐食物中毒调查分析

目的通过一起亚硝酸盐食物中毒的调查检测及分析,总结经验,为制定防治方法提供依据。方法用盐酸萘乙二胺法检测样品中的亚硝酸盐。结果在卤制食物、患者的洗胃液及呕吐物中均检出亚硝酸盐。结论食物中毒为卤制食物引起的亚硝酸盐中毒。     

Effects of nitrite and nitrate on the growth and acidogenicity of Streptococcus mutans

It is hypothesised that exogenous nitrite acidified by metabolic products of acidogenic bacteria in the mouth will be converted to products which inhibit growth of the bacteria in question which contribute to dental caries.

Objectives. The aims of this study were (1) to test the activity of both sodium nitrate and sodium nitrite at differing concentrations on the ability of Streptococcus mutans to lower the pH of its surroundings and hence (2) to determine whether either nitrate or nitrite might be bactericidal or bacteriostatic against S. mutans.

Methods. S. mutans NCTC 10449^T was cultured in a liquid medium to which either sodium nitrate or sodium nitrite was added to a final concentration of 0.0, 0.2, 2.0, 20 or 200 mM, of which the first acted as a test substance negative control. After 24 h, the cultures were streaked onto agar to test for growth and the remaining culture used for pH measurement. The Mann–Whitney U-Test was used for statistical comparison of pH values.

Results. Nitrite at concentrations of 20 and 200 mM had a highly significant inhibitory effect (p<0.001) on the ability of S. mutans NCTC 10449^T to lower pH. Moreover, bacteria that had been subjected to these levels of nitrite were unable to recover on solid medium. Nitrate had no such effect on either the growth of the bacteria or on their ability to lower pH.

Conclusions. It is concluded that nitrite, at final concentrations of either 20 or 200 mM, is both bactericidal and anti-acidogenic with respect to S. mutans, while lower concentrations of nitrite and all concentrations of nitrate are ineffective. Nitrite might be worthy of consideration as a mouth-rinse constituent.     

苯酚与亚硝酸根相互作用分光光度法测定亚硝酸根

目的:测定肉与肉制品中微量亚硝酸根含量。方法:在盐酸介质中,苯酚与亚硝酸根相互作用,生成亚硝基苯酚,该溶液在最大吸收波长为350 nm。据此建立测定亚硝酸根的方法。结果:线性范围为0 mg/L～10 mg/L,检出限为0.29 mg/L。结论:方法应用于肉与肉制品中微量亚硝酸根含量测定,结果满意。     

离子色谱法测定鸭绿江流域地表水中亚硝酸盐氮含量

目的建立准确、快速测定地表水中亚硝酸盐氮含量的方法。方法水样经0.22μm水系滤膜过滤后,以20 mmol/L氢氧化钾为淋洗液,用保留时间定性,峰面积定量。结果该方法回收率为96.0%~100.6%,RSD为0.56%,最低检出浓度为5.0μg/L,线性范围0.05~5.00 mg/L,r=0.999 9。结论该法测定亚硝酸盐氮含量简便、快速、选择性好,检出限可以满足水质分析要求,可同时测定F-、C l-、NO2--N、NO3--N、SO42-等离子含量。     

牛奶与乳饮料中痕量亚硝酸盐的快速荧光检测法

目的 建立牛奶与乳饮料品中痕量亚硝酸盐的快速荧光检测方法。方法 样品经乙醇沉淀蛋白质后,于适量样液中加入L-酪氨酸(L-Tyr),在酸性介质和加热条件下,样液中的亚硝酸盐氧化L-酪氨酸(L-Tyr),在碱性介质中氧化产物可产生很强荧光,标准曲线法定量。结果 方法线性范围为4～40 ng,检出限为0.04mg/kg,相对标准偏差小于10%,加标回收率为87.8%~90.1%。结论 该方法灵敏、准确、快速、分析成本低,适合于牛奶和乳饮料中痕量亚硝酸盐的快速检测。     

Nitrate-nitrite-nitrosamines exposure and the risk of type 1 diabetes: A review of current data

The potential toxic effects of nitrate-nitrite-nitrosamine on pancreatic β cell have remained a controversial issue over the past two decades. In this study, we reviewed epidemiological studies investigated the associations between nitrate-nitrite-nitrosamines exposure, from both diet and drinking water to ascertain whether these compounds may contribute to development of type 1 diabetes. To identify relevant studies, a systematic search strategy of Pub Med, Scopus, and Science Direct was conducted using queries including the key words "nitrate", "nitrite", "nitrosamine" with "type 1 diabetes" or "insulin dependent diabetes mellitus". All searches were limited to studies published in English. Ecologic surveys, case-control and cohort studies have indicated conflicting results in relation to nitrate-nitrite exposure from drinking water and the risk of type 1 diabetes. A null, sometimes even negative association has been mainly reported in regions with a mean nitrate levels 25 mg/L in drinking water, while increased risk of type 1 diabetes was observed in those with a maximum nitrate levels 40-80 mg/L. Limited data are available regarding the potential diabetogenic effect of nitrite from drinking water, although there is evidence indicating dietary nitrite could be a risk factor for development of type 1 diabetes, an effect however that seems to be significant in a higher range of acceptable limit for nitrate/nitrite. Current data regarding dietary exposure of nitrosamine and development of type 1 diabetes is also inconsistent. Considering to an increasing trend of type 1 diabetes mellitus(T1DM) along with an elevated nitrate-nitrite exposure, additional research is critical to clarify potential harmful effects of nitrate-nitritenitrosamine exposure on β-cell autoimmunity and the risk of T1DM.