Measurement Of Nitric Oxide Research Articles

Investigation on the NO formation of ammonia oxidation in a shock tube applying tunable diode laser absorption spectroscopy

The time-resolved nitric oxide (NO) measurements of NH3/O2/Ar mixtures using tunable diode laser absorption spectroscopy (TDLAS) were performed in a shock tube covering the temperature range of 1581-2720 K with an average pressure of 3.08 bar and three equivalence ratios of 0.5, 1.0 and 1.5. Considerable differences in the shape, amplitude and phase of NO profiles were observed for different temperatures and equivalence ratios. Two characteristic parameters (NOmax: maximum NO concentration; Pos_half_NOmax: the time from time zero (P5, T5) to the time corresponding to the position of half NOmax) were extracted for quantitative analysis. Generally, lower temperatures and higher equivalence ratios lead to lower NOmax. Pos_half_NOmax is retarded with lower temperatures, but it is not sensitive to equivalence ratios. The comparisons between experimental and predicted results by nine literature kinetic models reveal that no mechanism can well reproduce the NO time histories for all cases. The performance of each mechanism was quantitatively evaluated by the methodology proposed in this study. The Glarborg et al. mechanism (Prog. Energy Combust. Sci., 2018) shows the best performance in predicting NOmax and complete NO profiles while the Shrestha et al. mechanism (Proc. Combust. Inst., 2021) shows the best performance in Pos_half_NOmax prediction. NH3→NH2→NH→HNO→NO is identified as the main reaction pathway for NO formation, where NH3→NH2→H2NO→(HNOH)→NH3 and NH3→NH2(→NH)→N2H2→NH3 dominate in high (> 2300 K) and low temperature (< 1900 K) regimes, respectively. The NO consumption observed at temperatures over 2300 K and in rich mixture at temperatures below 1900 K were found to be attributed to N + NO <=> N2 + O and excessive NH/NH2 radicals, respectively. Such kind of consumption disappear in lean and stoichiometric mixtures (<1900 K) due to decomposition of HONO through HONO (+M) <=> NO + OH (+M). The Glarborg et al. mechanism was modified by updating the rate coefficients of NH3 + H <=> NH2 + H2 from the Shrestha et al. mechanism. The modified mechanism shows improved accuracy in Pos_half_NOmax prediction and becomes the best-performed model both in predicting the amplitude and phase of the NO profiles among all ten mechanisms.

Fluorescence-free quantitative measurements of nitric oxide and major species in an ammonia/air flame with Raman spectroscopy

Raman spectroscopy is a powerful technique that allows for simultaneous measurements of multiple species; however, it suffers from low signal intensity and, in diagnostics of ammonia (NH3) combustion, strong flame fluorescence. The current work re-introduces a multipass setup to perform enhanced quantitative Raman spectroscopy measurements of major species and nitric oxide (NO) in a premixed laminar lean (φ = 0.9) NH3 flame. A way to deal with the strong flame reaction-zone fluorescence is proposed and validated. The measurements were performed using both the second (532 nm, NO detection) and third (355 nm, major species and temperature) harmonics of an Nd:YAG laser. The acquired data sets were compared to the simulation data obtained with two chemical kinetic mechanisms. The reported average post-flame concentration of NO reaches a plateau at 3900 ± 120 ppm, and the detection limit is 700 ppm. The 355 nm excitation wavelength proved to provide close to no flame fluorescence, which allowed for measurements across the entire flame from reactants to products. Thus, major species profiles were acquired, and the concentration and temperature results are in good agreement with the simulation data. Lastly, possible error sources are estimated and ways to minimize them are proposed.

Hesperidin Preferentially Stimulates Transient Receptor Potential Vanilloid 1, Leading to NO Production and Mas Receptor Expression in Human Umbilical Vein Endothelial Cells.

Here, the mechanism of vasorelaxant Mas receptor (MasR) expression elevated by hesperidin in spontaneously hypertensive rats was investigated in human umbilical vein endothelial cells (HUVECs). HUVECs were cultured with 1 μM hesperidin for 2 h, following the measurements of nitric oxide (NO) production and vasomotor-related receptors' expression. Hesperidin significantly promoted NO production (224.1 ± 18.3%, P < 0.01 vs control) in the HUVECs. Only the MasR expression was upregulated (141.2 ± 12.5%, P < 0.05 vs control), whereas a MasR antagonist did not alter the hesperidin-induced NO production. When a transient receptor potential vanilloid 1 (TRPV1) was knocked down by silencing RNA or Ca2+/calmodulin-dependent kinase II (CaMKII) and p38 mitogen-activated protein kinase (p38 MAPK) were inhibited, the increased MasR expression by hesperidin was abrogated. The inhibitions of CaMKII and endothelial NO synthase (eNOS) abolished the hesperidin-induced NO production. The structure-activity relationship analysis of flavonoids demonstrated that the B ring of the twisted flavonoid skeleton with a hydroxy group at the 3' position was a crucial factor for TRPV1 stimulation. Taken together, it was demonstrated that hesperidin may stimulate TRPV1-mediated cascades, leading to the activation of two signaling axes, CaMKII/p38 MAPK/MasR expression and CaMKII/eNOS/NO production in HUVECs.

Importance of measuring Fractional Exhaled Nitric Oxide (FeNO) in the management of asthma

Asthma is characterized by chronic airway inflammation leading to respiratory symptoms (dyspnea, wheezing, chest tightness and cough). So direct measure of the level of inflammation can be of paramount importance in the proper understanding of severity of asthma. Nitric oxide (NO) isa product of inflammation in the airways and an important regulator of immune responses that is overproduced in asthma. For this purpose, the measurement of Fractional Exhaled Nitric Oxide (FeNO) has been used since the early years of the current century as a non-invasive, easy-to-assess tool useful for diagnosing and managing asthma. In this narrative review we extended our effort to explain the usefulness of FeNO as a predictor of response to inhaled corticosteroids (ICSs), to monitor adherence and as a diagnostic tool in asthma management. Bangladesh J Medicine 2022; 33: 241-246

Initial effects of post-harvest ditch cleaning on greenhouse gas fluxes in a hemiboreal peatland forest

Ditch cleaning (DC) is a well-established forestry practice across Fennoscandia to lower water table levels (WTL) and thereby facilitate the establishment of tree seedlings following clear-cutting. However, the implications from these activities for ecosystem-atmosphere greenhouse gas (GHG) exchanges are poorly understood at present. We assessed the initial DC effects on the GHG fluxes in a forest clear-cut on a drained fertile peatland in hemiboreal Sweden, by comparing chamber measurements of carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O) fluxes from soil and ditches in DC and uncleaned (UC) areas over the first two post-harvest years. We also evaluated spatial effects by comparing fluxes at 4 m and 40 m from ditches. We found that 2 years after DC, mean (±standard error) WTL of −65 ± 2 cm was significantly lower in the DC area compared to −56 ± 2 cm in the UC area. We further observed lower gross primary production and ecosystem respiration in the first year after DC which coincided with delayed development of herbaceous ground vegetation. We also found higher CH4 uptake but no difference in N2O fluxes after DC. Greater CH4 uptake occurred at 4 m compared to 40 m away from both cleaned and uncleaned ditches. Model extrapolation suggests that total annual GHG emissions in the second year were reduced from 49.4 ± 17.0 t-CO2-eq-ha−1-year−1 in the UC area to 27.8 ± 10.3 t-CO2-eq-ha−1-year−1 in the DC area. A flux partitioning approach suggested that this was likely caused by decreased heterotrophic respiration, possibly because of enhanced soil dryness following DC during the dry meteorological conditions. CH4 and N2O fluxes from clear-cut areas contributed <2 % to the total (soil, ditches) GHG budget. Similarly the area-weighted contributions by CO2 and CH4 emissions from both cleaned and uncleaned ditches were <2 %. Thus, our study highlights that DC may considerably alter the post-harvest GHG fluxes of drained peatland forests. However, long-term observations under various site conditions and forest rotation stages are warranted to better understand DC effects on the forest GHG balance.

The Cytotoxic Effects of Zinc Oxide Nanoparticles on SW480 Cell Lines and Measurement of Nitric Oxide in Cell Culture Medium

Background: Colorectal cancer (CRC) is one of the most common gastrointestinal cancers worldwide. It is the second leading cause of death in women after breast cancer. Objectives: The present study aimed to determine the cytotoxic effects of zinc oxide (ZnO) nanoparticles on colon cancer (SW480) viability and nitric oxide (NO) level in vitro. Methods: In this experimental study, the values of 15.62, 31.25, 62.5, 125, 250, and 500 μg/mL of ZnO nanoparticles were considered to treat SW480 cells for 24 hours. The MTT method was used to determine cell viability. The amount of NO was also measured using the grease method. An analysis of variance (ANOVA) was used to analyze the data. Results: Treatment of SW480 cells with ZnO nanoparticles resulted in decreased viability in a dose-dependent pattern. NO concentration significantly increased in response to an effective dose of ZnO nanoparticles (108 µg/mL) compared to the control group (P &lt; 0.001). Conclusions: ZnO nanoparticles have cytotoxic effects on colon cancer cells. The cytotoxic effect of ZnO nanoparticles on colon cancer cells is partly mediated by NO in cancer cells.

Antileishmanial activity, cytotoxicity and cellular response of amphotericin B in combination with crotamine derived from Crotalus durissus terrificus venom using in vitro and in silico approaches

ObjectiveTo investigate the in vitro activity, synergism, cytotoxicity and cellular immunological response, as well as the molecular affinity between amphotericin B (AmB) and crotamine (CTA), derived from Crotalus durissus terrificus venom against Leishmania amazonensis. MethodsThis study performed the inhibition of promastigotes and amastigotes’ growth under different concentrations of the drug and pharmacological combinations (AmB + CTA) based on the Berimbaum method (synergism study). The lactate dehydrogenase (LDH) quantification method was used to determine the cytotoxicity of the drug and combinations employing four cell lines (J774, HepG2, VERO, and C2C12). Following, the levels of Tumour Necrose Factor-alpha (TNF-α) and Interleukin-12 (IL-12) cytokines, using enzyme-linked immunosorbent assay (ELISA) and nitrites, as an indirect measure of Nitric Oxide (NO), using the Griess reaction were assessed in the supernatants of infected macrophages. In silico approach (molecular docking and dynamics) and binding affinity (surface plasmon resonance) between the drug and toxin were also investigated. ResultsCTA enhanced AmB effect against promastigote and amastigote forms of L. amazonensis, decreased the drug toxicity in different cell lines and induced the production of important Th1-like cytokines and NO by infected macrophages. The pharmacological combination also displayed consistent molecular interactions with low energy of coupling and a concentration-dependent profile. ConclusionOur data suggest that this pharmacological approach is a promising alternative treatment against L. amazonensis infection due to the improved activity (synergistic effect) achieved against the parasites’ forms and to the decreased cytotoxic effect.

Cross-sectional Study of Workers Employed at a Copper Smelter-Effects of Long-term Exposures to Copper on Lung Function and Chronic Inflammation.

The aim of the study was to assess the effect of exposure to copper-containing dust on lung function and inflammatory endpoints among workers of a German copper plant, effects rarely studied before. One hundred four copper-exposed smelter workers and 70 referent workers from the precious metal and lead facilities were included, with different metal exposures in both groups due to the different process materials. Body plethysmography, exhaled nitric oxide (FeNO) measurements, and blood sampling were conducted in all workers. Smoking status and the use of respiratory protective equipment were considered. In a subgroup of 40 nonsmoking volunteers (28 copper-exposed and 12 referents), sputum biomarkers were assessed. Median lung function values of both copper-exposed and the referent groups were within reference ranges of "healthy" individuals, and statistical differences between the groups were mostly not evident. Similarly, differences in blood and sputum biomarkers were too small to be biologically relevant. The results suggest the absence of the detectable effects of copper-containing dust exposure on lung function or chronic inflammation within the investigated cohort.

Adolescent Athletes at Risk of Exercise-Induced Bronchoconstriction: A Result of Training or Pre-Existing Asthma?

Exercise may trigger bronchoconstriction, especially in a group of athletes in whom bronchospasm during exercise is reported to occur more frequently than in nonathletes. The aim of this study was to determine the prevalence and environmental risk factors contributing to exercise-induced bronchoconstriction (EIB) in adolescent athletes. A prospective study was conducted among a group of 101 adolescent athletes who underwent spirometry, exercise challenge, fractional exhaled nitric oxide (FeNO) measurements, and allergy assessment. The study group was divided into three subgroups of athletes based on the most common sports environments: swimmers, “indoor” athletes, and “outdoor” athletes. The clinical evaluation demonstrated a high frequency of EIB in the study group. Moreover, a large proportion of the athletes in whom EIB was observed reported no pre-existing symptoms suggestive of bronchospasm or asthma. Among patients without a previous diagnosis of asthma, clinical evaluation confirmed 22% with positive exercise challenges, compared with 77% of adolescents with negative test results. Moreover, among the athletes with a history of asthma, 39% had positive exercise challenges. Both EIB and asthma are common conditions that affect adolescent athletes. Physicians should pay particular attention to this group, as the symptoms can lead to under- and overdiagnosis.

An Evidence-Based Review of Application Devices for Nitric Oxide Concentration Determination from Exhaled Air in the Diagnosis of Inflammation and Treatment Monitoring

The measurement of nitric oxide (NO) in exhaled air is used in diagnostics and monitoring the pathologies not only in the respiratory system but also in the oral cavity. It has shown a huge increase in its level in asthma and diseases of the oral cavity. It seems reasonable to undertake research on the impact of inflammation on the level of NO in exhaled air. The aim of the study is to make an evidence-based review of the application of NO levels in exhaled air in the diagnosis of inflammation and treatment monitoring on the basis of selected measuring devices. Methods and Results: This paper presents an example of the application of NO measurement in exhaled air in individual human systems. Selected measuring devices, their non-invasiveness, and their advantages are described. Discussion: The usefulness of this diagnostic method in pathologies of the oral cavity was noted. Conclusions: Measuring the level of NO in exhaled air seems to be a useful diagnostic method.

Predictors of successful weaning

Abstract Background Early release of patients from mechanical ventilation and intubation associated with significant decrease in mortality and morbidities. Aim Evaluation of echocardiography and oxidative stress markers in the prediction of weaning failure. Patients and methods In all, 120 mechanically ventilated patients were included in the study. Patients were evaluated by tissue Doppler transthoracic echocardiography before and during the spontaneous breathing trial (SBT). In addition to ventilatory parameters, blood samples were obtained for the measurement of lipid peroxidase, glutathione oxidase, and nitric oxide. Different parameters were compared between failed and successful weaning groups. Results During SBT, respiratory rate, heart rate, and rapid shallow breathing index (RSBI) were significantly increased compared with before SBT. The serum level of nitric oxide before SBT was significantly decreased in the failed group. All cardiac dimensions significantly increased during SBT compared with before SBT; moreover, the left ventricular dimensions increased significantly in the failed group during SBT. There was significant decrease in right ventricular systolic function during SBT as estimated by tricuspid annular plane systolic excursion (TAPSE) and myocardial performance index. Weaning success was positively correlated with tidal volume, TAPSE, and nitric oxide, while negatively correlated with lipid peroxidase, respiratory rate, left ventricular end-diastolic dimension, and E/E’ of lateral mitral valve annulus. Tidal volume more than or equal to 493 ml before SBT had the highest sensitivity for predicting successful weaning; on the other hand, during SBT left ventricular end-diastolic dimension less than or equal to 5.05 cm had 100% sensitivity and TAPSE more than or equal to 1.65 had 88.9% sensitivity. Respiratory rate less than or equal to 27.5 during SBT had the highest specificity (72.7%). Conclusion In comparison to oxidative stress markers, clinical assessment and bedside transthoracic echocardiography have higher sensitivity, so they can be considered valuable and cheap predictors of successful weaning.

An EC-QCL based dual-species (CH4/N2O) detection method at 7.8 µm in mid-IR region for simultaneous applications of atmospheric monitoring and breath diagnostics

A high-sensitive optical detection method was designed and developed at 7.8 μm mid-IR region by coupling a room-temperature operated continuous wave (cw) external-cavity quantum cascade laser (EC-QCL) with an astigmatic multipass cell. The detection strategy operates in the principle of wavelength modulation spectroscopy with second harmonic detection strategy (2f-WMS). We have shown that the methodology has the ability for simultaneous and real-time quantitative measurements of nitrous oxide (N2O) and methane (CH4) in ambient air and human exhaled breath in parts per billion (ppb) levels via an extremely narrow single QCL scan of ∼0.06 cm−1. The high-resolution rotational-vibrational interference-free 2f-WMS spectra of CH4 and N2O centred at 1297.8192 cm−1 and 1297.8314 cm−1, respectively were simultaneously acquired with 0.20 s data acquisition time in the optimized experimental conditions. Minimum detection limits of 6 ppb for N2O and 30 ppb CH4 were achieved by the cw-EC-QCL based 2f-WMS detection method, thus opening its broad applications in environmental monitoring and non-invasive biomedical diagnostics.

Screening Accuracy of FeNO Measurement for Childhood Asthma in a Community Setting.

(1) Background: The exhaled fractional nitric oxide is a well-recognized biomarker used in clinical settings for controlling and managing asthma. Less is known about the value of Fractional Exhaled Nitric Oxide (FeNO) measurement in epidemiological studies on childhood asthma, although available evidence suggests that an increased FeNO is associated with an increased risk of asthma. (2) Aim: The aim of the study was to assess FeNO accuracy in the identification of children with asthma, participants in a population-based respiratory survey. (3) Material and methods: The cross-sectional study included 449 children, 224 (49.9%) boys and 225 (50.1%) girls aged 6–10 years. The FeNO was measured in 449 children; Spirometry tests were completed with 441 children, but technically acceptable spirometry was done in 350. All participants fulfilled the questionnaire (ISAAC) for assessment of the status of their respiratory system on which diagnosis was based on. FeNO and Spirometry were performed according to ERS/ATS recommendations. (4) Results: The FeNO was significantly higher in asthmatic children (n = 22): 27.3 ± 21.3 ppb; with allergic rhinitis (n = 106): 9.9 ± 21.6 ppb, with atopic dermatitis (n = 67) 20.8 ± 25.0 ppb, with an asthmatic tendency (n = 27): 19.8 ± 16.0 ppb in comparison to children without any respiratory/atopy symptoms. The highest diagnostic odds ratio and area under the curve were found in any treated asthma or asthma without any atopic symptoms in relation to FeNO cutoff > 35 ppb; DOR 4.85 and 8.37; AUC 0.615 and 0.795, respectively. The adjustment for spirometry parameters did not improve the diagnostic accuracy of FeNO. In each FeNO cutoff, there were more false positive than true positive subjects. (5) Conclusions. The best diagnostic accuracy of FeNO was for isolated asthma without any atopy against children without any coexisting respiratory or allergic disease. The sensitivity and specificity did not reach the required values for a good screening tool; therefore, it should not be used in epidemiological settings.

Challenges in the successful management of asthma during conception, pregnancy and delivery.

Asthma and infertility are the most common disorders among women of reproductive age. Time to pregnancy is prolonged in women with asthma, and importantly, age seems to be a more important risk factor regarding fertility in women with asthma compared to women without asthma. Some data have shown a higher frequency of miscarriages in women with asthma, although the data are conflicting on this issue as studies have observed no association between asthma and pregnancy loss. Furthermore, studies have shown no negative effect of asthma on the total number of offspring. Pregnancy may, thus, have a significant impact on women with asthma, as well as on their offspring. The age of the women has an important impact on ability to conceive, but also for the pregnancy itself, with higher risk of uncontrolled asthma as well as asthma exacerbations with increasing age. Well-controlled asthma decreases the risk of maternal and fetal complications, while poorly controlled and undertreated asthma is associated with a range of risks for both mother and fetus. Asthma treatment should follow the general guidelines for asthma therapy, irrespective of pregnancy status, including treatment with inhaled corticosteroids, β2-agonists and muscarinic antagonists. Targeted treatment with biologics for severe asthma seems to be without important adverse effects. The use of systemic corticosteroids may be associated with adverse events during the first trimester; however, an exacerbation with the associated risk of hypoxaemia is worse for the fetus. Best possible asthma control may be achieved using repeated measurements of fractional exhaled nitric oxide (F ENO), as the use of F ENO compared with symptoms registration only has been shown to reduce exacerbation rate. In conclusion, women with asthma should be encouraged to conceive at an early age, might experience miscarriages, but the number of offspring are the same as in women without asthma. Well treated asthma is important for the well-being of both the mother and the unborn fetus.

Measurement and Interpretation of Fractional Exhaled Nitric Oxide

Nitric oxide is produced by the human lungs and increases in response to type 2 inflammation. The level of fractional exhaled nitric oxide (FeNO) may reflect type 2 inflammation in the airways, which is related to eosinophilic inflammation and treatment responsiveness to corticosteroids. The FeNO test is a non-invasive, simple, and safe point-of-care test to evaluate airway inflammation. It has been standardized for clinical use and has been widely utilized in daily medical practice. However, various intrinsic and extrinsic factors can affect FeNO levels, and understanding and controlling such factors will improve the utility of this measure. The FeNO test can be used to confirm an asthma diagnosis, predict treatment responses to corticosteroids, and guide inhaled corticosteroid therapy for asthma treatment.

Castor Bean (Ricinus communis L.) Polyphenolic Extracts Exhibited Anti-inflammatory Effects on LPS-Stimulated RAW 264.7 Macrophages

ObjectivesThis research aimed to explore the anti-inflammatory properties of two different aqueous extracts from Mexican Castor bean leaves accessions (R1 and R2) in lipopolysaccharide (LPS)-challenged murine RAW 264.7 cells. MethodsTwo leaves accessions (S1 and S2) grown in Amazcala (Mexico) were washed, sun-dried (35–60 °C), ground, and screened (250 mm particle size). Aqueous extracts were prepared by dissolving 100 mg of the powders in 10 mL distilled water and maintained in a water bath (40 °C) under stirring for 1 h. Samples were then centrifuged (3500 g, 15 min, 4 °C). Total phenolics (TP), total flavonoids (TF), condensed tannins (CT), and antioxidant capacity measurements (ABTS and DPPH) were quantified spectrophotometrically. Individual phenolics were quantified by HPLC-DAD, and metabolomic analysis from gas chromatography (GC)-MS was conducted using MetaboAnalyst. The extracts were assayed against LPS-induced RAW 264.7 cells, whereas cell viability (MTT) and nitric oxide (Griess reaction) measurements were carried out. ResultsThe total polyphenolic composition of the extracts showed no differences (P < 0.05) on their TF and CT composition, but S2 displayed a higher TF content than S1. Identifying individual phenolic compounds by HPLC-DAD highlighted ellagic and gallic acids (17.13–28.77 mg/g dry weight) as the primary phenolic acids, whereas S2 showed the highest abundance of (+)-catechin. S1 was the extract with the highest DPPH antioxidant capacity (P < 0.05) (80.17%). None of the extracts was cytotoxic at the evaluated concentrations (10–50% v/v), but S2 was more effective in inhibiting nitric oxide production (44.94%). ConclusionsThe extracts showed anti-inflammatory potential by inhibiting NO production and could be used to manufacture bioactive compounds-rich food-grade-based ingredients. However, as ricinine, a toxic protein, has been reported in the leaves, methods eliminating ricinine from the extracts are required for safely using the extracts. Funding SourcesThe authors acknowledge “Fondos para el Desarrollo del Conocimiento (FONDEC) from Universidad Autónoma de Querétaro (UAQ) 8289, Registry SVSU-DV-2021–09) for the provided resources.

Treatment guided by fractional exhaled nitric oxide in addition to standard care in 6- to 15-year-olds with asthma: the RAACENO RCT

BackgroundThe role of fractional exhaled nitric oxide in guiding asthma treatment in children is uncertain.ObjectiveTo compare treatment guided by both fractional exhaled nitric oxide and symptoms (intervention) with treatment guided by symptoms alone (standard care) in children with asthma who are at risk of an asthma exacerbation, in terms of the number of asthma exacerbations over 12 months.DesignThis was a pragmatic, multicentre, randomised controlled trial with embedded cost-effectiveness and qualitative process evaluations. Randomisation (1 : 1) was carried out using a remote web-based system and was minimised on recruitment centre, age, sex and British Thoracic Society treatment step. Clinical teams and participants were not blind to treatment allocation.SettingThe trial took place in 35 hospitals and seven primary care practices in the UK.ParticipantsChildren aged 6–15 years with a diagnosis of asthma who were currently prescribed inhaled corticosteroids and who had one or more parent-/patient-reported asthma exacerbation treated with oral corticosteroids in the 12 months prior to recruitment.InterventionsAsthma treatment guided by symptoms alone (standard care) and asthma treatment guided by symptoms plus fractional exhaled nitric oxide (intervention). Treatment recommendations in both groups were protocolised within a web-based algorithm, incorporating inhaled corticosteroid adherence (objectively measured using an electronic logging device) and current treatment.Main outcome measuresThe primary outcome measure was asthma exacerbations treated with oral corticosteroids in the year post randomisation. Secondary outcomes included time to first exacerbation, number of exacerbations, lung function, fractional exhaled nitric oxide, daily dose of inhaled corticosteroid, asthma control and quality of life.ResultsIn total, 509 eligible participants were recruited and the primary outcome was available for 506 participants. The primary outcome occurred in 123 out of 255 (48.2%) participants in the intervention group and 129 out of 251 (51.4%) participants in the standard-care group (adjusted odds ratio 0.88, 95% confidence interval 0.61 to 1.27). There was algorithm non-compliance on 21% of assessments. Per-protocol and complier-average causal effect analysis did not change the interpretation. This non-statistically significant estimate was consistent across predefined subgroups. There were no differences between the groups in secondary outcomes. There were no serious adverse events or deaths. No meaningful differences in health service costs, direct patient costs or indirect costs to society were identified between the groups. The economic evaluation does not provide evidence to support the cost-effectiveness of the intervention. In the qualitative process evaluation, 15 trial staff and six families were interviewed. Overall, their experiences were positive. The intervention was broadly acceptable, with caveats around clinicians using the algorithm recommendation as a guide and wariness around extreme step ups/downs in treatment in the light of contextual factors not being taken into account by the algorithm.LimitationsPotential limitations included the choice of cut-off point to define uncontrolled asthma and the change in fractional exhaled nitric oxide to trigger a change in treatment. Furthermore, the treatment decisions in the two groups may not have been sufficiently different to create a difference in outcomes.ConclusionsThe RAACENO (Reducing Asthma Attacks in Children using Exhaled Nitric Oxide) trial findings do not support the routine use of fractional exhaled nitric oxide measurements as part of asthma management in a secondary care setting. The potential for other objective markers to guide asthma management in children needs to be evaluated.Trial registrationThis trial was registered as ISRCTN67875351.FundingThis project was funded by the Efficacy and Mechanism Evaluation (EME) programme, a MRC and National Institute for Health and Care Research (NIHR) partnership. This will be published in full inEfficacy and Mechanism Evaluation; Vol. 9, No. 4. See the NIHR Journals Library website for further project information.

Soil Greenhouse Gas Emissions in Different Pastures Implemented as a Management Strategy for Climate Change

The increase in global average temperature has significant implications for food security and agriculture production. Grass species adapted to new climate scenarios are essential for the success of livestock production. The aim of this study was to evaluate different forage species, providing animal feed during critical dry periods as an adaptation strategy for livestock grazing systems, and its implications for greenhouse gas (GHG) emissions. The field experiment was conducted during September 2015 to September 2017, with four treatments (n = 5, completely randomized block design), including two perennial forages, Bromus valdivianus (Bromus), Lotus corniculatus (Lotus), alone and in a mixture pasture (Br/L). As a control treatment, the forage species commonly seeded by the farmer was used (hybrid ryegrasses + Oat, Control). One-half of the plots was used for nitrous oxide (N2O) and methane (CH4) measurements, and the remaining half for destructive soil and forage sampling. Gas fluxes were measured using the static chambers technique. Cumulative emissions of N–N2O, C–CH4 and CO2−eq were not affected by treatments, averaging 1.7 kg N–N2O ha−1, 3.2 kg C–CH4 ha−1 and 635.5 kg CO2 ha−1, respectively (p &gt; 0.05). However, emission intensity tended to be lower for Br/L compared with other treatments (p = 0.06) during the second year, while pasture yield was greater for Br/L (p &lt; 0.05). The control showed a greater average pasture yield (first and second years) compared to other treatments, with the highest metabolizable energy and the lowest crude protein content. Our results suggest that a mix pasture Br/L as a management strategy would promote farm adaptation, given that it favors pasture yield at critical dry periods during the year. This inclusion also reduces N–N2O emissions from grassland soils as well as favoring C–CH4 capture. Our study determined that N–N2O and C–CH4 emissions were regulated by soil variables, mainly soil moisture and soil temperature. Extension and knowledge transfer should be provided to farmers to account for potential adoption barriers, such as low short-term yield.

Toxicological effects of the mixed iron oxide nanoparticle (Fe3O4 NP) on murine fibroblasts LA-9

ABSTRACT The increase in large-scale production of magnetic nanoparticles (NP) associated with the incomplete comprehensive knowledge regarding the potential risks of their use on environmental and human health makes it necessary to study the biological effects of these particles on organisms at the cellular level. The aim of this study to examine the cellular effects on fibroblast lineage LA-9 after exposure to mixed iron oxide NP (Fe3O4 NP). The following analyses were performed: field emission gun–scanning electron microscopy (SEM-FEG), dynamic light scattering (DLS), zeta potential, ultraviolet/visible region spectroscopy (UV/VIS), and attenuated total reactance-Fourier transform infrared (ATR-FTIR) spectroscopy analyses for characterization of the NP. The assays included cell viability, morphology, clonogenic potential, oxidative stress as measurement of reactive oxygen species (ROS) and nitric oxide (NO) levels, cytokines quantification interleukin 6 (IL-6) and tumor necrosis factor (TNF), NP uptake, and cell death. The size of Fe3O4 NP was 26.3 nm when evaluated in water through DLS. Fe3O4 NP did not reduce fibroblast cell viability until the highest concentration tested (250 µg/ml), which showed a decrease in clonogenic potential as well as small morphological changes after exposure for 48 and 72 hr. The NP concentration of 250 µg/ml induced enhanced ROS and NO production after 24 hr treatment. The uptake assay exhibited time-dependent Fe3O4 NP internalization at all concentrations tested with no significant cell death. Hence, exposure of fibroblasts to Fe3O4 NP-induced oxidative stress but not reduced cell viability or death. However, the decrease in the clonogenic potential at the highest concentration demonstrates cytotoxic effects attributed to Fe3O4 NP which occurred on the 7th day after exposure.

Detection of Nitric Oxide from Chickpea Using DAF Fluorescence and Chemiluminescence Methods.

The free radical nitric oxide (NO) has emerged as an important signal molecule in plants, due to its involvement in various plant growth, development, and stress responses. For elucidating the role of NO, it is very important to precisely determine, localize, and quantify NO levels. Due to a relatively short half-life and its rapid, complex reactivity with other radicals, together with its capacity to diffuse from the source of production, the quantification of NO in whole plants, tissues, organelles, and extracts is notoriously difficult. Hence, it is essential to employ sensitive procedures for precise detection of NO. Currently available methods can fulfill many requirements to precisely determine NO, but each method has several advantages and pitfalls. In this article, we describe a detailed procedure for the measurement of NO by diaminofluorescein (DAF) in cell-permeable forms (DAF-FM-DA). In this method, the tissues are immersed in DAF-FM DA, leading to their diffusion from the plasma membrane to the inside of the cell, where intracellular esterases cleave the ester bonds, leading to DAF-FM release. The resulting DAF-FM reacts with intracellularly generated NO and forms highly fluorescent triazolofluorescein (DAF-FMT), which can be localized and monitored by fluorescence or confocal microscopy, and can also be detected via fluorimetry and flow cytometry. DAF dyes are very popular as they are non-invasive, relatively easy to handle, and commercially available. Another precise and very sensitive method is chemiluminescence detection of NO, where NO reacts with ozone (O3 ), leading to emission of a quantum of light from which NO can be calculated. Using chickpea seedlings, we describe in detail the measurement of NO using DAF-FM-DA and chemiluminescence methods. © 2022 Wiley Periodicals LLC. Basic Protocol 1: Measurement of nitric oxide from chickpea seedlings using DAF-FM DA fluorescence with fluorescence and confocal microscopy Basic Protocol 2: Chemiluminescence detection of nitric oxide from chickpea seedlings.