Topic
Nitrite
About: Nitrite is a research topic. Over the lifetime, 15425 publications have been published within this topic receiving 484581 citations.
Papers published on a yearly basis
Papers
More filters
TL;DR: First structural information on both types of Cu centres for the reduced form of NiR from Alcaligenes xylosoxidans (AxNiR) is presented using X-ray absorption spectroscopy and it is proposed that the two links between the Cu sites of AxNiR are utilised for electron transfer and for communicating the status of the type 2 Cu site, respectively.
108 citations
Journal Article•
TL;DR: In this article, the authors measured ammonium and nitrite in barley roots in response to anoxia, uncouplers or cellular acidification, and found that ammonium assimilation rates were also impaired by anoxias.
108 citations
TL;DR: Increases in cerebrospinal fluid nitrite and nitrate concentrations peaked at 30 to 42 hrs after severe closed-head injury and were associated with injury Severity Score, suggesting that increased nitric oxide production in the brain is associated with Injury severity and death.
Abstract: OBJECTIVES To measure cerebrospinal fluid and plasma nitrite and nitrate concentrations as indicators of nitric oxide production in adults after severe closed-head injury. To determine if there is an association between cerebrospinal fluid and plasma nitrite and nitrate concentrations, and cerebral blood flow, arterio-jugular oxygen content difference, injury severity, and outcome after severe closed-head injury. DESIGN A prospective, clinical study. SETTING Multidisciplinary intensive care unit. PATIENTS Fifteen comatose (Glasgow Coma Scale score of < or = 7) adult patients with severe closed-head injury were studied during the prospective, randomized evaluation of the effect of moderate hypothermia (32 degrees C for 24 hrs) on neurologic outcome after closed-head injury. Seven patients were in the hypothermic group and eight patients were in the normothermic treatment group. INTERVENTIONS None. MEASUREMENTS AND MAIN RESULTS Patients were examined sequentially, every 12 hrs for 2 days. Intraventricular cerebrospinal fluid was assayed for nitrite and nitrate concentrations. Cerebral blood flow was measured by the 133xenon intravenous method. Simultaneous blood samples were obtained for measurements of arterio-jugular oxygen content difference and plasma nitrite and nitrate concentrations. Cerebral metabolic rate for oxygen was calculated. Cerebrospinal fluid nitrite and nitrate concentrations were highest at 30 to 42 hrs vs. 6 to 18, 18 to 30, and 42 to 54 hrs (26.4 +/- 3.3 vs. 17.3 +/- 2.1, 20.0 +/- 2.2, and 18.8 +/- 2.4 microM, respectively, p < .05). There was no difference over time in plasma nitrite and nitrate concentrations. Cerebral blood flow was increased and arterio-jugular oxygen content difference was reduced at 18 to 30, 30 to 42, and 42 to 54 hrs vs. 6 to 18 hrs (p < .05). At 30 to 42 hrs, cerebrospinal fluid nitrite and nitrate concentrations were 80% higher in patients who died vs. survivors (36.4 +/- 3.2 vs. 20.2 +/- 3.6, p < .05). Using a generalized, multivariate, linear regression model, both plasma nitrite and nitrate concentrations and injury Severity Score independently predicted cerebrospinal fluid nitrite and nitrate concentrations (p < .00001 and p = .0053, respectively). Cerebral blood flow and arterio-jugular oxygen content difference were not associated with cerebrospinal fluid or plasma nitrite and nitrate concentrations using this model. Cerebrospinal fluid nitrite and nitrate concentrations were increased over time in hypothermic vs. normothermic patients. But, where this difference occurred could not be determined by multiple comparisons (p = .03). The hypothermic patients had lower admission Glasgow Coma Scale scores than normothermic patients (p = .04) and tended to have higher injury Severity Scores (p = .09). CONCLUSIONS Increases in cerebrospinal fluid nitrite and nitrate concentrations peaked at 30 to 42 hrs after severe closed-head injury. This increase in cerebrospinal fluid nitrite and nitrate concentrations was greater in nonsurvivors. Also, cerebrospinal fluid and plasma nitrite and nitrate concentrations were associated with injury Severity Score, suggesting that increased nitric oxide production in the brain is associated with injury severity and death. Hypothermia did not prevent the increase in cerebrospinal fluid nitrite and nitrate concentrations. Further study is required to determine the source of this increase in cerebrospinal fluid nitrite and nitrate concentrations and to further define the relationship to outcome and the effect of hypothermia on this process.
108 citations
TL;DR: In batch tests with the biofilm covered carriers, it was possible for the first time to examine the nitrogen conversion at the intact biofilm and to establish the deammonification processes in a continuous flow moving-bed pilot plant.
108 citations
TL;DR: The hypothesis that the ergogenicity of nitrate supplementation is linked to specific effects on vascular, metabolic, and contractile function in Type II muscle is examined.
Abstract: Dietary nitrate supplementation increases circulating nitrite concentration, and the subsequent reduction of nitrite to nitric oxide is promoted in hypoxic environments. Given that PO2 is lower in Type II compared with Type I muscle, this article examines the hypothesis that the ergogenicity of nitrate supplementation is linked to specific effects on vascular, metabolic, and contractile function in Type II muscle.
108 citations