离子色谱法测定替硝唑片中亚硝酸盐的含量

目的：用离子色谱法测定替硝唑片中亚硝酸根的含量。方法：采用IonpacAS11-HC型分离柱（4mm×250mm）；淋冼液：氢氧化钾溶液（20mmoL／L）；电导检测法。结果：亚硝酸根进样量在0．001-0．05μg范围内呈良好的线性关系，平均回收率为99．6％。结论：本方法简便、准确、快速，适用于替硝唑片中亚硝酸根的含量测定。     

Intragastric CO2 and Nitric Oxide Participate in the Regulation of Peptoneinduced Gastrin Release in Humans

Background: Moderate acidification of the gastric lumen inhibits peptone-induced gastrin release. The aim of the present study was to investigate if the gastric acid neutralization products CO₂ (from secreted HCO₃^-) and NO (from reduced salivary nitrite) could act as intermediate messengers between luminal acidity and the inhibition of peptone-induced gastrin release. Methods: Fourteen healthy volunteers (mean age, 27 years; range, 20-39 years; 3 women) participated in the study. Intragastric perfusion with saline or peptone was performed on the healthy volunteers. Venous blood samples were analyzed for serum gastrin concentrations. Intragastric NO was measured by chemiluminescence. Results: Basal serum gastrin ranged between 11 and 23 pmol/l. Peptone in Sörensen's phosphated buffer (pH 6.9, P_CO2     

呼出气冷凝液白三烯、8异前列腺素、硝酸盐/亚硝酸盐检测在哮喘中的应用及孟鲁司特对炎症指标的影响

目的:观察支气管哮喘患者呼出气冷凝液(EBC)中半胱氨酰白三烯C4(LTC4)、8异前列腺素(8-isoprostane)、硝酸盐/亚硝酸盐(NO2/NO3)水平及孟鲁司特干预前后炎症指标的变化.方法:选择哮喘非急性发作期患者30例,均予孟鲁司特10 mg,每晚一次口服,疗程1月,分别于治疗前及治疗后检测EBC中LTC4、8-isoprostane、NO2/NO3水平,另选择30例健康人为健康对照组.结果:哮喘组LTC4( 55±17) ng/mL、8-isoprostane( 13±9)ng/mL、NO2/NO3(4.2±1.2) ng/mL显著高于正常对照组(17±17)、(7±6)、(3.2±0.6) ng/mL(均P＜0.01).哮喘组治疗前LTC4 (55±17) ng/mL显著高于治疗后(38±14) ng/mL,P＜0.01.哮喘组治疗前8- isoprostane (13±9)ng/mL,高于治疗后(11±6) ng/mL,但差异无统计学意义(P＞0.05).哮喘组治疗前NO2 /NO3 水平为(4.2±1.2) ng/mL,治疗后为(4.1±1.4) ng/mL,差异无统计学意义(P＞0.05).结论:检测哮喘患者EBC中LTC4、8-isoprostane、NO2/NO3水平可简便安全监测哮喘的气道炎症,孟鲁司特能降低EBC中LTC4水平,是一种有效的气道炎症抑制剂.     

尿液分析三项指标对早期发现尿路感染的作用

目的探讨尿液分析与尿培养相关性，快速准确诊断早期尿路感染。方法按照无菌操作的原则留取患者清洁中段尿液于无菌试管中送检。结果205例尿液培养共检出195株细菌，阳性率95．1％。其中WBC≥2＋、细菌数≥4000的140例中检出细菌133株，阳性率95．0％；WBC≥2＋、亚硝酸盐阳性的25例中检出细菌23株，阳性率92．0％；亚硝酸盐阳性、细菌数〉14000的30例中检出细菌26株，阳性率86．7％；WBC≥2＋、细菌数〉14000、亚硝酸盐阳性的20例中全部检出细菌，阳性率100％。结论三项指标综合分析判断，二项阳性做尿液培养对早期发现尿路感染患者提供快速、准确的诊断。培养阳性者根据药敏试验合理应用抗生素，为临床成功治疗提供保障。     

一起亚硝酸盐食物中毒的调查及思考

目的对一起食物中毒的可疑中毒食品和呕吐物进行分析,以确定引起中毒的原因。方法结合现场卫生学调查、流行病学调查、临床诊断症状等相关资料,分析调查可疑食物中毒的原因。结果在被检可疑中毒食品和呕吐物中检出亚硝酸盐。结论食用过量亚硝酸盐为引起此次食物中毒的原因,应加强监督管理,预防亚硝酸盐中毒事件的发生。     

肉制品中亚硝酸盐含量催化比色测定

本文根据亚硝酸根在酸性条件下能促进氯酸钾氧化考马斯亮蓝G反应,建立了肉制品中亚硝盐含量测定新方法。最大吸收峰590nm,线性范围0～0.50×10~(-5),回收率94～109％。     

Comparison of hydroxylamine, 4-dimethylaminophenol and nitrite protection against cyanide poisoning in mice

Intraperitoneal doses of 4-dimethylaminophenol hydrochloride (DMAP), hydroxylamine hydrochloride (H₂NOH) and sodium nitrite (NaNO₂) were found where each converted a maximum of about 37% of the total circulating hemoglobin in mice to methemoglobin. Those doses in mmol/kg were: 0.29 for DMAP, 1.1 for H₂NOH, and 1.1 for NaNO₂. For DMAP and H₂NOH the peak was sharp and at about 7 min after injection whereas for NaNO₂ the peak was much broader and at about 40 min. The i.p. LD₅₀'s in mmol/kg were: 0.48 for DMAP, 1.8 for H₂NOH and 2.3 for NaNO₂. When mice pretreated with each of the methemoglobin-generating agents were challenged with sodium cyanide, the ratios of the LD₅₀'s in protected mice to those in control mice (protection index, PI) were 1.5 for H₂NOH, 2.0 for DMAP and 3.1 for NaNO₂. When sodium thiosulfate was also given in combination with each of the three methemoglobin-generating agents, the protective effect was at least additive. The PI against sodium sulfide was also significantly greater in mice pretreated with NaNO₂ than in mice given H₂NOH. Methemoglobins generated from human and mouse hemoglobins by either NaNO₂ or by H₂NOH had identical binding affinities (dissociation constants) for cyanide. When human red cells containing methemoglobin generated by exposure to either NaNO₂ or H₂NOH were injected into the peritoneal cavity of mice and then followed by cyanide challenges, there was no difference in the PI for the two kinds of methemoglobin. Not only was the PI the same in each case with human cells, but it was also identical with that in mice given NaNO₂ systemically to generate the same total amount of methemoglobin. The difference in PI between NaNO₂ and H₂NOH (or DMAP) in mice appears to be related to the high rate of methemoglobin reductase activity in mouse RBC. It appears likely that cyanmethemoglobin is a substrate for mouse methemoglobin reductase activity, and that NaNO₂ is an inhibitor of mouse methemoglobin reductase. No differences in cyanide antagonism between NaNO₂ and H₂NOH would be anticipated in humans because of the slow rates of methemoglobin reduction in human red cells.     

Nitrite binding to cytochrome P-450 from liver microsomes of trout (Salmo gairdneri Rich.) and effects on two microsomal enzymes

Addition of nitrite to dithionite-reduced trout liver microsomes leads to the conversion of cytochrome P-450 into a cytochrome P-420-NO complex, as it does in mammalian microsomes. A loss in cytochrome P-450 and an inhibition of aminopyrine demethylase (AP) activity were observed in vitro at nitrite-concentrations found in the liver of trout exposed in vivo to this toxin. Nitrite had no effect on dimethylaniline monooxygenase (DMA), a cytochrome P-450-independent enzyme.     

溴酸钾氧化亮绿SF催化光度法测定纯净水中微量亚硝酸盐

[目的]建立一种高灵敏度的新方法测定纯净水中微量亚硝酸盐。[方法]基于亚硝酸盐催化溴酸钾氧化亮绿SF而使其褪色所起的作用而建立的催化光度法。[结果]本法检出限为0.05μg/L,国标法检出限为0.003 3 mg/L。本法测定范围为0.05~20μg/L,其测定结果与国标法相比差异无统计学意义(t=0.28,P>0.50)。[结论]用于纯净水中亚硝酸盐的测定,获得了满意结果。     

牛乳与乳粉中亚硝酸盐和硝酸盐的固相萃取离子色谱测定法

目的建立离子色谱同时测定牛乳与乳粉中亚硝酸盐和硝酸盐含量的方法。方法采用甲醇-乙腈对样品进行萃取并离心,上清液经C18小柱净化后,利用IonPac AS 11—HC柱分离和电导检测器测定,外标法定量。结果亚硝酸盐:线性范围0.02～0.20 mg/L,相关系数0.999 5,样品加标回收率90.0%～104.8%,RSD 3.5%,检出限为牛乳0.002 mg/kg,乳粉0.006 mg/kg;硝酸盐:线性范围0.20～2.0 mg/L,相关系数0.999 4,样品加标回收率90.0～105.8%,RSD 2.3%,检出限为牛乳0.006 mg/kg,乳粉0.03 mg/kg。结论该方法简便,快速,适合牛乳与乳粉中亚硝酸盐和硝酸盐含量的测定。