Redox therapeutics in hepatic ischemia reperfusion injury

Ischemia-reperfusion plays a major role in the injury experienced by the liver during transplantation. Much work has been done recently investigating the role of redox species in hepatic ischemia-reperfusion. As animal models are better characterized and developed, and more insights are gained into the pathophysiology of hepatic ischemia reperfusion injury in humans the questions into exactly how oxidants participate in this injury are becoming more refined. These questions include effects of cellular location, timing of injury, and ability of therapeutics to access this site are increasing our appreciation of the complexity of ischemia reperfusion and improving attempts to ameliorate its effects. In this review, we aim to discuss the various methods to alter redox chemistry during ischemia reperfusion injury and future prospects for preventing organ injury during hepatic ischemia reperfusion.     

Effects of dietary inorganic nitrate on static and dynamic breath-holding in humans

Inorganic nitrate has been shown to reduce oxygen cost during exercise. Since the nitrate-nitrite-NO pathway is facilitated during hypoxia, we investigated the effects of dietary nitrate on oxygen consumption and cardiovascular responses during apnea. These variables were measured in two randomized, double-blind, placebo-controlled, crossover protocols at rest and ergometer exercise in competitive breath-hold divers. Subjects held their breath for predetermined times along with maximum effort apneas after two separate 3-day periods with supplementation of potassium nitrate/placebo.     

Melatonin protects against epirubicin-induced cardiotoxicity

We investigated the cytoprotective effect of melatonin in epirubicin-induced cardiotoxicity using four experimental groups of male Wistar rats: untreated control rats, epirubicin-treated rats, epirubicin+melatonin-treated rats, and melatonin-treated rats. We examined the histopathological and biochemical effects of melatonin on the epirubicin-induced changes and measured the levels of the lipid peroxidation end-product (malondialdehyde, MDA), an indicator of nitric oxide (NO) synthesis (nitrite/nitrate production), and reduced glutathione (GSH) in the heart. We also studied the extracellular matrix components (fibronectin, laminin) in the heart. Vacuole formation, mitochondrial deformation and degeneration, and disordered myofibrillary structures were detected ultrastructurally in the epirubicin-treated group. The degeneration was reduced in the heart tissues of the epirubicin+melatonin group. Epirubicin increased the nitrite/nitrate production, but did not change the MDA and GSH levels significantly. Melatonin treatment lowered the nitrite/nitrate concentrations, while increasing the GSH levels, which exceeded the levels in epirubicin+melatonin-treated rats. We conclude that the epirubicin increased the nitrozative stress, not the oxidative stress, in heart tissue, and the cardioprotective effect of melatonin was partially attributed to the suppression of epirubicin-induced nitrozative stress. These results suggest that melatonin partially protects against epirubicin-induced cardiotoxicity.     

唾液硝酸盐、亚硝酸盐检测方法的探讨

目的 通过比较几种不同测定唾液硝酸盐、亚硝酸盐含量的方法来寻求最佳测定唾液微量硝酸盐、亚硝酸盐的标准方法.方法 比较经典的Griess法、镉柱法和高压液相色谱法(HPLC)对含不同浓度的硝酸盐、亚硝酸盐标准品以及10位健康志愿者混合唾液样本中硝酸盐、亚硝酸盐含量的最低检出限和硝酸盐、亚硝酸盐回收率.结果 Griess法和镉柱法测定唾液硝酸盐、亚硝酸盐的最低检出限NO-3为10ng/μl,NO-2为1ng/μl,回收率为91.2%;HPLC法测定唾液硝酸盐、亚硝酸盐的最低检出限为NO-3为0.8ng/μl,NO-2为0.1ng/μl,回收率达到97.6%.结论 HPLC在微量硝酸盐、亚硝酸盐检测中的灵敏度明显高于经典的Griess法.     

2011-2013年新乡市熟肉制品中亚硝酸盐含量监测分析

目的了解新乡市市场上熟肉制品中亚硝酸盐含量情况。方法 2011年-2013年连续3年对市场上抽检熟肉样品中亚硝酸盐含量的监测结果进行统计和分析。结果连续3年检测熟肉制品共计421份,熟肉制品亚硝酸盐含量总合格率为79.3%。其中熟鸡肉和熟鸭肉亚硝酸盐含量总合格率分别是97.1%,96.4%,熟牛肉和熟猪肉亚硝酸盐含量总合格率分别只有76.9%,72.7%。结论新乡市市售熟肉制品中还存在超标使用和滥用亚硝酸盐的状况,特别是熟牛肉和熟猪肉中,建议引起有关部门的重视,加强监管,提高熟肉制品的食用安全性。     

高脂血症患者红细胞左旋精氨酸转运及一氧化氮变化的研究

目的:观察单纯高脂血症患者红细胞左旋精氨酸(L-Arg)转运及一氧化氮的变化。 方法:高脂血症患者12例(高脂组)和健康者12例(对照组)。两组在年龄、性别上匹配。空腹取血测定血脂水平、血浆亚硝酸盐(NO2-)含量;以3H-L-Arg测定红细胞L-Arg转运。 结果:高脂组血浆中NO2-水平为对照组的4.7倍(P<0.01),高脂组红细胞L-Arg最大转运速率(Vmax)较对照组增加33％(P<0.01),其中y+载体介导Vmax增加47％(P<0.01),而总转运、y+载体介导转运亲和力(Km)无明显变化(P>0.05);y+L载体介导转运与对照组差异无统计学意义(P>0.05)。 结论:高脂血症时红细胞L-Arg/一氧化氮系统发生异常改变。     

一起亚硝酸盐引起食物中毒事件的调查

目的调查了解2004年7月20日卫辉市某化工厂13名工人先后出现恶心、呕吐、口唇紫绀等症状的发病原因。方法通过流行病学调查结合临床表现及实验室检查进行分析。结果发病的13名工人均进食了被亚硝酸盐污染的水或食物,经及时治疗,中毒工人全部康复。中毒事件迅速控制。结论这是一起自来水被亚硝酸盐污染引起的急性食物中毒事件。应加强对生活饮用水的卫生监督与管理。     

微量元素钼的抗癌作用

通过对近几年国内外文献检索,综述了微量元素钼防癌抗癌作用研究进展。结果表明,钼对人体肿瘤有预防和治疗作用,特别是胃肠道癌等受钼的影响最明显,补钼能使其发病率和死亡率下降。钼的防癌抗癌机制是多方面的,其中,钼能中断亚硝胺在体内的合成是抗癌重要机理之一。     

一起亚硝酸盐引起的食物中毒的调查分析

目的查明泗水县苗馆镇一起食物中毒的原因,以采取措施,防止类似事件的发生。方法通过流行病学调查,结合临床症状和实验室检验等进行分析。结果凡加工过的食品中均含有亚硝酸钠,将亚硝酸钠误用作食盐是导致食物中毒的主要原因。结论加强食品卫生知识培训,加强日常监督力度,重点加强农村群众的食品卫生安全教育,是防止类似食物中毒事件的有效手段。     

Influence of oxygen, temperature and carbon dioxide on nitric oxide formation from nitrite as measured in expired gas from in situ perfused rabbit lungs

In biological systems, nitric oxide (NO) may be generated non-enzymatically from nitrite (nitrite-derived NO), in addition to nitric oxide synthase-catalyzed (NOS-derived) L-arginine-dependent formation. Through recordings of expired NO, we studied the influence of temperature on NOS- and nitrite-derived NO in the perfused lung. We also studied the impact of other influencing factors (O(2), CO(2), and pH) on nitrite-derived NO in the same system. Both NO-generating systems exhibited biphasic temperature dependence with a positive correlation between temperature and NO generation that peaked between 42 and 44 degrees C. The nitrite-derived NO generation was enhanced by hypoxia alone (>20 x after 5 min) and further by concomitant increase in CO(2). The CO(2) effect could not be explained by changes in extracellular pH and was unaltered by acetazolamide. We conclude that the temperature dependence in the known enzyme-catalyzed NOS-derived NO and especially in the nitrite-derived NO strengthens the hypothesis that an enzyme could be involved in nitrite-derived NO formation. The enhancement of nitrite-derived NO by increases in CO(2) suggests that this system could be of importance to improve perfusion in ischemic tissues.