Nitrate in public water supplies and the risk of renal cell carcinoma

Drinking water and dietary sources of nitrate and nitrite can react in vivo with amines and amides to form N-nitroso compounds (NOC), potent animal carcinogens. Nitrate is a widespread contaminant of drinking water supplies especially in agricultural areas. We conducted a population-based case–control study of renal cell carcinoma in 1986–1989 in Iowa, a state with elevated levels in many public water supplies. We collected a lifetime water source history, but due to limited monitoring data, most analyses focused on the subpopulation, who used Iowa public supplies with nitrate measurements (actual or imputed data) for ≥70% of their person-years since 1960 (201 cases, 1,244 controls). We computed the average nitrate level and years using a public supply with nitrate levels >5 and >10 mg/l. Dietary nitrate and nitrite were estimated from a 55-item food frequency questionnaire. There was no association of renal cell carcinoma with the average nitrate level and years using public supplies >5 and >10 mg/l nitrate-nitrogen (10+ years >5 mg/l odds ratio (OR) = 1.03, 95% confidence interval (CI) 0.66, 1.60). However, higher nitrate exposure was associated with an increased risk among subgroups with above the median red meat intake (10+ years >5 mg/l OR = 1.91, 95% CI 1.04–3.51) or below the median vitamin C intake (10+ years >5 mg/l OR = 1.90, 95% CI 1.01, 3.56), dietary factors that increase the endogenous formation of NOC. Exclusion of long-term Des Moines residents, a large proportion of the high exposure categories, attenuated the association. These findings deserve additional study in populations with high water nitrate intake and information on dietary intakes. The U.S. Government's right to retain a non-exclusive, royalty-free license in and to any copyright is acknowledged.     

广东省阳江某刀具厂急性亚硝酸盐中毒调查

目的　揭示广东省阳江某刀具厂急性中毒事件的主要原因 ,探讨中毒的主要危险因素。方法　对工厂管理人员、中毒患者、经治医生、生活用水的污染过程以及工业废水的处理、排放细节进行现况调查。采用面对面问卷调查员工的发病情况和主要暴露因素。结果　发病 36例 ,罹患率为16 .4 % (36 2 2 0 )。饮用水集中在当天下午上班后 13∶0 0至 15∶30 ,发病高峰在 15∶0 0左右 ,潜伏期中位数为 90min。不同饮水量的工人罹患率不同 ,随着饮水量的增加 ,罹患率也增加 ,存在比较明显的剂量反应关系 (χ2 趋势 =79.115 ,P <0 .0 1)。实验室检测工人饮用后的残留水亚硝酸盐含量严重超标。结论　此事件为一起饮用水被亚硝酸盐污染导致的急性中毒。当地刀具生产企业对亚硝酸盐等有毒化学品的保管使用、供水系统的设计以及工业废水处理排放后对人群健康和环境的影响值得有关部门的密切关注。     

Nitrite Reduces Acute Lung Injury and Improves Survival in a Rat Lung Transplantation Model

Ischemia/reperfusion injury (IRI) is the most common cause of early mortality following lung transplantation (LTx). We hypothesized that nitrite, an endogenous source of nitric oxide (NO), may protect lung grafts from IRI. Rat lung grafts were stored in preservation solution at 4°C for 6 hours. Both grafts and recipients were treated with nitrite. Nitrite treatment was associated with significantly higher levels of tissue oxygenation, lower levels of cytokines and neutrophil/macrophage infiltration, lower myeloperoxidase activity, reduced oxidative injury and increased cGMP levels in grafts than in the controls. Treatment with either a nitric oxide scavenger or a soluble guanylyl cyclase (sGC) inhibitor diminished the beneficial effects of nitrite and decreased cGMP concentrations. These results suggest that nitric oxide, generated from nitrite, is the molecule responsible for the effects of nitrite via the nitric oxide/sGC/cGMP pathway. Allopurinol, a xanthine oxidoreductase (XOR) inhibitor, abrogated the protective effects of nitrite, suggesting that XOR is a key enzyme in the conversion of nitrite to nitric oxide. In vitro experiments demonstrated that nitrite prevented apoptosis in pulmonary endothelial cells. Nitrite also exhibits longer survival rate in recipients than control. In conclusion, nitrite inhibits lung IRI following cold preservation and had higher survival rate in LTx model.     

肉制品中亚硝酸盐含量的检测与分析

目的:测定肉制品中亚硝酸盐含量,以了解山西省亚硝酸盐使用现状。方法:依据GB 5009.33-2010《食品中亚硝酸盐与硝酸盐的测定》检测。结果:共检测165份肉制品,平均检出率83.6%,平均超标率为2.42%。结论:应加强对畜类肉制品中亚硝酸盐的监控力度,以确保消费者能购买到卫生安全的食品。     

Plasma nitric oxide metabolite levels increase during successive exercise stress testing – A link to delayed ischemic preconditioning?

BACKGROUND:

Animal studies have shown that nitric oxide is involved in delayed ischemic preconditioning.

OBJECTIVES:

To determine whether plasma nitrates and nitrites (NO_x⁻, as measure of nitric oxide) are modified by two consecutive effort tests and whether these changes translate into clinical improvement

METHODS:

Twenty-two patients with ischemic heart disease each performed two effort tests at 24-h intervals. Plasma NO_x⁻ level was determined and compared before and after both stress tests. Peak effort, double product at peak effort and maximal ST segment depression were considered clinical endpoints and were compared between the two tests.

RESULTS:

Plasma NO_x⁻increased slightly after the first exercise test compared with pretest value (17.05±1.6 μmol/mL versus 15.38±1.4 μmol/mL). In turn, after the second test there was a significant rise in NO_x⁻ level (23.65±2.2 μmol/mL versus 15.10±1.3 μmol/mL, P<0.03). The pretest values were almost identical between the two tests. Peak effort and double product at peak effort remained unchanged between the two tests. Although ischemic stress was the same, ST depression was significantly lower (P<0.01) for the second test (0.85±0.06 mm versus 1.73±0.16 mm).

CONCLUSION:

Our study shows an increased plasma NO_x⁻level after the second of two consecutive exercise stress tests at 24-h intervals, along with a decrease of electrocardiographic consequences of approximately the same ischemic stress. These findings are consistent with experimental data in animals, which point to nitric oxide as a trigger and effector of ischemic preconditioning.     

大理州市市售肉制品中亚硝酸盐含量检测结果分析

目的了解当前大理州市售肉制品中亚硝酸盐含量,为加强食品安全管理监督提供科学依据,并对其潜在危害进行分析。方法选择大理州有代表性的农贸市场及超市采集各类肉制品样品45件,根据GB/T 5009.33-2010《食品中亚硝酸盐与硝酸盐的测定》,选用萘乙二胺分光光度法进行测定,并对检测结果进行统计分析。结果本次抽检的45件肉制品中亚硝酸盐含量的合格率为95.56%,各类肉制品中硝酸盐含量的合格率差异无统计学意义（χ2=2.193,P〉0.05）,超过限值（≥30 mg/kg）为2件,占4.44%。结论大理州市市售肉制品的生产加工中普遍使用亚硝酸盐基本规范,不过仍存在一定问题,有关部门还需加强监管。     

β2- and β3-adrenergic receptors drive COMT-dependent pain by increasing production of nitric oxide and cytokines

Decreased activity of catechol-O-methyltransferase (COMT), an enzyme that metabolizes catecholamines, contributes to pain in humans and animals. Previously, we demonstrated that development of COMT-dependent pain is mediated by both β₂- and β₃-adrenergic receptors (β₂ARs and β₃ARs). Here we investigated molecules downstream of β₂- and β₃ARs driving pain in animals with decreased COMT activity. Based on evidence linking their role in pain and synthesis downstream of β₂- and β₃AR stimulation, we hypothesized that nitric oxide (NO) and proinflammatory cytokines drive COMT-dependent pain. To test this, we measured plasma NO derivatives and cytokines in rats receiving the COMT inhibitor OR486 in the presence or absence of the β₂AR antagonist ICI118,551 + β₃AR antagonist SR59320A. We also assessed whether the NO synthase inhibitor L-N_G-nitroarginine methyl ester (L-NAME) and cytokine-neutralizing antibodies block the development of COMT-dependent pain. Results showed that animals receiving OR486 exhibited higher levels of NO derivatives, tumor necrosis factor α (TNFα), interleukin-1β (IL-1β), interleukin-6 (IL-6), and chemokine (C-C motif) ligand 2 (CCL2) in a β₂- and β₃AR-dependent manner. Additionally, inhibition of NO synthases and neutralization of the innate immunity cytokines TNFα, IL-1β, and IL-6 blocked the development of COMT-dependent pain. Finally, we found that NO influences TNFα, IL-1β, IL-6, and CCL2 levels, whereas TNFα and IL-6 influence NO levels. Altogether, these results demonstrate that β₂- and β₃ARs contribute to COMT-dependent pain, at least partly, by increasing NO and cytokines. Furthermore, they identify β₂- and β₃ARs, NO, and proinflammatory cytokines as potential therapeutic targets for pain patients with abnormalities in COMT physiology.     

济宁市咸菜亚硝酸盐含量及消化道癌流行病学分析

为研究强致癌物亚硝胺的前体亚硝酸盐在咸菜中的含量，对２４个品种３９９份咸菜及原料等进行了检测。结果表明，不同地区、不同品种咸菜亚硝酸盐含量不同，盐碱地区含量较高，胡萝卜、青萝卜、大头菜含量较高，与腌渍时间、温湿度、生产工艺等有关。对本地区和全省同期消化道癌流行病学进行对照分析表明，其发病率较高，可能与经济落后、咸菜食用量较大有关。     

PC-Ⅰ型水处理设备净化水质效果分析

目的 了解PC-Ⅰ型水处理设备对水质的净化效果。方法 取经PC-Ⅰ型水处理器处理前后的二次供水的水质样品，按《生活饮用水卫生规范》(2001年6月版)进行检测。结果 二次供水经深度净化处理后，细菌总数由处理前的120个／ml下降到处理后的10个／ml。氨氮去除率为98．92％，亚硝酸盐氮去除率为99．40％，符合生活饮用水卫生标准。结论 PC-Ⅰ型饮用水深度净化处理设备能有效地降低饮用水中的氨氮、亚硝酸盐氮的浓度及细菌总数。