Oxidant-antioxidant status in Egyptian children with sickle cell anemia: a single center based study

Objectivethe present study was conducted to investigate the oxidant-antioxidant status in Egyptian children with sickle cell anemia.Methodsthe serum levels of total antioxidant capacity (TAO), paraoxonase (PON), vitamin E, nitrite, and malondialdehyde (MDA) were measured in 40 steady state children with homozygous sickle cell anemia (24 males and 16 females) and 20 apparently healthy age- and gender-matched controls.Resultsmean serum TAO, PON, vitamin E, and nitrite levels were significantly lower in the group with sickle cell anemia, whereas mean serum MDA was significantly higher in these children compared to controls. No significant differences in mean levels of TAO, PON, nitrite, vitamin E, and MDA were found in sickle cell anemia patients receiving hydroxyurea when compared with those not receiving hydroxyurea. A significant negative correlation between serum nitrite and the occurrence of vaso-occlusive crises (VOC) was observed (r = −0.3, p = 0.04). PON level was found to be positively correlated with patients’ weight and BMI (r = −0.4, p = 0.01; r = −0.7, p < 0.001, respectively), but not with frequency of VOC. The area under the curve of serum nitrite in predicting occurrence of VOC was 0.782, versus 0.701 for PON, and 0.650 for TAO (p = 0.006). Serum MDA was not correlated with nitrite, PON, TAO, or vitamin E levels. No significant correlations were detected between serum nitrite and hemoglobin or antioxidant enzymes.Conclusionchildren with sickle cell anemia have chronic oxidative stress that may result in increased VOC, and decreased serum nitrite may be associated with increases in VOC frequency. A novel finding in this study is the decrease in PON level in these patients, which is an interesting subject for further research.     

南通市2008年-2011年市售熟肉制品中亚硝酸盐含量的调查分析

目的:了解南通市市场上熟肉制品中亚硝酸盐含量情况,为政府相关部门提供卫生监管的依据。方法:对市场上抽检的423份样品中亚硝酸盐的监测结果进行统计与分析。结果:亚硝酸盐含量的检出率57.45%,合格率为96.93%,超标率为3.07%,定型包装的合格率高于非定型包装,定型包装的合格率100%,调查中最高含量达3200 mg/kg,超过国家限量标准100倍。结论:南通市市售熟肉制品中存在普遍使用亚硝酸盐的情况,部分样品还存在超标使用和滥用亚硝酸盐的状况,提示应引起相关部门的重视,加大监督力度,以提高熟肉制品的食用安全性。     

Impact of metabolic activity of beta cells on cytokine-induced damage and recovery of rat pancreatic islets

The influence of beta cell activity on cytokineinduced functional and structural impairments as well as the ability of those damaged cells to recover were investigated. Rat islets cultured for 4 days in the presence of 5, 10, and 30 mmol/l glucose were exposed to interferon-γ (IFN, 500 U/ml) and tumor necrosis factor-α (TNF, 250 U/ml) for the last 24 h. After cytokine removal islets were allowed to recover spontaneously in culture medium containing 10 mmol/l glucose for a further 7 days. Cytokines significantly inhibited insulin release into culture medium, insulin storage, glucose-stimulated insulin secretion, protein, and DNA synthesis. In the presence of cytokines there was a six- to eightfold increase in nitrite production by the islets. The functional impairments were more pronounced in metabolically stimulated beta cells. In addition, cytokines caused membrane alterations as indicated by increased spontaneous chromium-51 release. The cytokines specifically induced the synthesis of two proteins (72 and 88 kDa, respectively). By immunoblotting, the 72-kDa protein was identified as heat shock protein. After a 1-week recovery period, insulin storage and stimulated insulin secretion of cytokine-treated islets were still significantly diminished. However, protein and DNA synthesis of cytokine-exposed islets returned to pre-exposure levels. In conclusion, high beta cell activity increases islet susceptibility to TNF+IFN. Cytokine-induced, longlasting, inhibitory effects are primarily directed to betacell-specific functions, while general vital cell functions clearly recover after cytokine removal. The induction of certain proteins and the increased protein synthesis and replication rate after cytokine removal might reflect activated repair processes.     

婴幼儿配方奶粉中亚硝酸盐的离子色谱测定方法

目的建立快速、准确检测婴幼儿配方奶粉中亚硝酸盐含量的离子色谱测定方法。方法样品经过超声处理,再通过0．22um滤膜、Ag柱、Na柱后以4．5mmol／L碳酸钠溶液、1mmol／L碳酸氢钠溶液为流动相,流速1．0mg／L,用保留时间定性峰面积定量。结果方法的平均回收率为105．3％,变异系数RSD4．87％,该法的最低定量下限为0．2mg／kg。结论离子色谱法测定婴幼儿配方奶粉中亚硝酸盐检出限满足国家标准限值,方法操作简便、灵敏度高、重现性好、方法准确等。     

离子色谱法测定纯净水中痕量亚硝酸根

目的：用离子色谱法测定纯净水中的痕量亚硝酸根。方法：含亚硝酸根离子的水样中加入一定量的甲醛，用离子色谱法测定，峰面积进行定量。结果：加入1．0mg／L甲醛，可延长亚硝酸盐的稳定时间，改善分析性能，方法的检出限为0．01mg／L，线性范围为0—30mg／L，线性相关系数r=0．9998，方法精密度（RSD）和准确度（P），分别为1．93％-3.70％和96．08％～104．06％。结论：该方法准确度高、精密度好，简便、快速，可直接测定水样中的亚硝酸根，结果满意。     

食源性亚硝酸盐中毒的实验室分析和判定

目的：对一学校食物中毒的可疑中毒食品和呕吐物进行了实验室化学分析，以确定引起中毒的原因。方法：可疑中毒食品样品和一呕吐物经研磨混匀后，加入保护性试剂和pH调节试剂，在弱酸性条件下，重氮化反应并形成紫红色化合物，然后比色测定。结果：60件被检可疑中毒食品和呕吐物中，13件检出亚硝酸盐。结论：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，可以明确判定食用过量亚硝酸盐为引起此次食物中毒的原因，并提出了判定原则和理论推断。同时，对卫生监督管理和卫生行政处罚的适用性、合理性、科学性进行了探讨。     

溴酸钾氧化荧光素测定亚硝酸盐含量

亚硝酸盐在酸性条件下能促进溴酸钾氧化荧光素,降低荧光强度,建立了荧光法测定肉品中微量亚硝酸盐新方法。激发波长500nm,发射波长510nm。回收率94～105％,在0～0.50μg/5ml范围内呈线性相关(r=0.997)。     

Sources of Intra-Oesophageal Nitric Oxide Production Following Intraluminal Acid Exposure

Background: The aim of the present study was to assess luminal nitric oxide (NO) levels in the oesophagus during baseline and acidic conditions and to clarify the sources of such oesophageal NO formation. Methods: Healthy volunteers received an intra-oesophageal infusion of either HCl (100 mM) or NaCl (150 mM) on two separate study days. After a low nitrate diet, nitrate load or no dietary restrictions/pretreatment, direct intraluminal measurements of NO formation were performed using a tonometric technique. Endoscopy was performed and mucosal biopsies were taken and analysed by means of immunohistochemistry, Western blot and RT-PCR. Results: No intra-oesophageal NO was detected during baseline conditions with pH neutrality. During the infusion of HCl the NO levels rose dramatically to around 12000 ppb. This high rate of NO formation fell by 95% following deviation of saliva. NO formation after an acute nitrate load was almost doubled during acid perfusion compared to control. Immunohistochemistry demonstrated distinct staining for iNOS in the oesophageal squamous epithelial cells, and Western blot and RT-PCR confirmed the presence of iNOS. Conclusion: Two sources exist for intra-oesophageal NO formation, both dependent on the luminal acidity: 1) chemical reduction of salivary nitrite, a mechanism related to dietary intake of nitrate, and 2) NO formation within the oesophageal mucosal epithelium by enzymatic degradation of L-arginine. In the latter case, the NO synthase has antigenic characteristics, indicating the inducible isoform, although a functional behaviour suggests an unconventional subtype.     

应用二阶导数极谱法在对氨基苯磺酸一盐酸萘乙二胺体系中测定血清中NO2-

目的评价二阶导数示波极谱法测定人血清中NO2-含量的方法。方法采用对氨基苯磺酸一盐酸萘乙二胺为测定体系,使用二阶导数极谱法测定血清中的NO2-含量。结果该方法测得正常成人的血清NO2-浓度为（233±0.06）mol／L,检出限为098mmol／L,线性范围为0．98～4638mmol／L,精密度为5O％,平均回收率为1055％。结论该方法是一种简单,易操作的测定血清NO2-的方法。     

In vitro antioxidant and anti–inflammatory activities of Korean blueberry (Vaccinium corymbosum L.) extracts

ObjectiveTo investigate in vitro antioxidant and anti-inflammatory activities of Korean blueberry (Vaccinium corymbosum L.).MethodsTotal phenolic and flavonoid contents of the Korean blueberry water and ethanol extracts were determined before determining the potential of the extracts as antioxidant. Antioxidant activity of the extracts was determined by following some well established methods for free radical scavenging such as 2,2-diphenyl-picrylhydrazyl hydrate, 1,2,2-azinobis-(3-ethylbenzothiazoline-6-sulfonicacid), free radical induced DNA damage, superoxide dismutase-like and catalase assay etc. Furthermore, 1-(4,5-dimethylthiazol-2-yl)-3,5-diphenylformazan and nitric oxide assay were performed to determine the anti-inflammatory activity of the extracts.ResultsTotal phenolic contents were found (115.0±3.0) and (4.2±3.0) mg GAE/100 g fresh mass for both extracts, respectively and flavonoid contents were (1 942.8±7.0) and (1 292.1±6.0) mg CE/100g fresh mass for water and ethonal extracts, respectively. Both the extracts displayed significant scavenging activity of some radicals such as 2,2-diphenyl-picrylhydrazyl hydrate (IC₅₀ at 1.8 mg/mL and 2.05 mg/mL, respectively), 1,2,2-azinobis-(3-ethylbenzothiazoline-6-sulfonicacid) (IC₅₀ at 1.5 mg/mL and 1.6 mg/mL, respectively) and nitrite (IC₅₀ at 1.7 mg/mL and 1.5 mg/mL, respectively) etc. The extracts were found to prevent inflammation as well by reducing nitric oxide production and cytotoxicity in cell.ConclusionsThe findings suggest that the fresh Korean blueberry could be used as a source of natural antioxidants and anti-inflammatory agents.