Nitric Oxide Levels In Children Research Articles

Long-term PM2.5 exposure is associated with asthma prevalence and exhaled nitric oxide levels in children.

Exhaled nitric oxide concentration (FENO) is a marker of airway inflammation. This study aimed to evaluate the association of air pollution exposure with FENO levels and asthma prevalence with respiratory symptoms in school children. We analyzed 4736 school children who reside in six townships near industrial areas in central Taiwan. We evaluated asthmatic symptoms, FENO, and conducted the environmental questionnaire. The personal exposure of PM2.5, NO, and SO2 was estimated using land-use regression models data on children's school and home addresses. Annual exposure to PM2.5 was associated with increased odds of physician-diagnosed asthma (OR = 1.595), exercise-induced wheezing (OR = 1.726), itchy eyes (OR = 1.417), and current nasal problems (OR = 1.334) (P < 0.05). FENO levels in the absence of infection were positively correlated with age, previous wheezing, allergic rhinitis, atopic eczema, near the road, and for children with high exposure to PM2.5 (P < 0.05). An increase of 1 μg/m3 PM2.5 exposure was significantly associated with a 1.0% increase in FENO levels for children after adjusting for potential confounding variables, including exposures to NO and SO2. Long-term exposures to PM2.5 posed a significant risk of asthma prevalence and airway inflammation in a community-based population of children. Annual exposure to PM2.5 was associated with increased odds of physician-diagnosed asthma and nasal problems and itchy eyes. Long-term exposures to PM2.5 were significantly associated with FENO levels after adjusting for potential confounding variables. This is first study to assess the association between FENO levels and long-term air pollution exposures in children near coal-based power plants. An increase of 1 μg/m3 annual PM2.5 exposure was significantly associated with a 1.0% increase in FENO levels. Long-term exposures to PM2.5 posed a significant risk of asthma prevalence and airway inflammation in a community-based population of children.

The prognostic implications of perioperative endogenous hydrogen sulfide and nitric oxide levels in children with congenital heart disease complicated by pulmonary arterial hypertension.

The goal of this study was to measure perioperative changes in endogenous hydrogen sulfide (H2S) and nitric oxide (NO) levels in children with congenital heart disease (CHD) complicated by pulmonary arterial hypertension (PAH), with the goal of better monitoring these children and evaluating their prognosis. For this study, we enrolled 48 normal control cases, 48 preoperative CHD cases including 16 without PAH, 16 with mild PAH, and 16 with moderate-to-severe PAH. We additionally enrolled a cohort of 32 other children with PAH-CHD that had undergone CHD correction prior to transfer to an intensive care unit (ICU). These children were further subdivided based on whether or not PAH was still present after operation (n = 16 per group). Spectrophotometry was used to assess endogenous H2S and NO levels at 24 and 48h postoperatively in each group. Correlations between postoperative endogenous H2S and NO levels at these two time points, as well as duration of mechanical ventilation, ICU length of stay, duration of hospitalization, and vasoactive drug score values at 24 and 48h postoperation were assessed. Endogenous H2S and NO values differed significantly between the control and preoperative CHD groups (P < 0.05). These values also differed significantly among the three different preoperative CHD subgroups and were negatively correlated with pulmonary arterial pressure (P < 0.05). Spearman rank correlation analyses indicated that endogenous H2S levels at 24 and 48h postoperation were negatively correlated with the duration of mechanical ventilation, ICU length of stay, and maximum vasoactive drug score values at both 24 and 48h postoperation. We similarly identified a negative correlation between NO concentrations at 24 and 48h postoperation and maximum vasoactive drug score at these same time points (P < 0.05).Conclusions: Endogenous H2S and NO levels are closely associated with CHD-PAH incidence, and there is a correlation between endogenous H2S levels and the postoperative prognosis of CHD in children. Higher H2S concentrations seem to correspond to better patient prognosis, and as such these values can be used as a prognostic index at an early time point. These values can additionally guide treatment efforts and improve outcomes among children with CHD-PAH. What is Known: • Hydrogen sulfide and nitric oxide are both vasodilating factors. • Hydrogen sulfide and nitric oxide can regulate pulmonary vascular remodeling, which is closely related to the occurrence and prognosis of pulmonary arterial hypertension. What is New: • This study was designed to explore the relationship between short-term prognostic indexes and hydrogen sulfide and nitric oxide levels, in an effort to provide a frame of reference for the postoperative monitoring and treatment of children with congenital heart disease complicated by pulmonary arterial hypertension.

Determination of dynamic thiol/disulphide homeostasis in children with tetralogy of Fallot and ventricular septal defect.

Oxidative stress may contribute to the pathogenesis of congenital heart defects, but the role of dynamic thiol/disulphide homeostasis has not been evaluated. The objective of this study was to assess whether there are changes in thiol/disulphide homeostasis and nitric oxide levels in children with tetralogy of Fallot (TOF) and ventricular septal defect (VSD). A total of 47 children with congenital heart defects (24 TOF and 23 VSD) and 47 healthy age- and sex-matched controls were included in this study. Serum total thiol and native thiol levels were measured using a novel automatic spectrophotometric method. The amount of dynamic disulphide bonds and related ratios were calculated from these values. Serum nitric oxide levels were detected using a chemiluminescence assay. We found that the average native thiol, total thiol, and disulphide levels were decreased in patients with VSD when compared with healthy individuals (p &lt; 0.001, p &lt; 0.001, and p &lt; 0.01, respectively). While native thiol levels were decreased (p &lt; 0.01), disulphide levels were elevated in the TOF group (p &lt; 0.05). We observed marked augmentation of disulphide/native thiol (p &lt; 0.001) and disulphide/total thiol ratios (p &lt; 0.01) in the TOF group. However, there was a significant decrease in native thiol/total thiol ratio in patients with TOF. No significant changes in these ratios were noted in the VSD group. We detected significant elevations in serum nitric oxide levels in children with TOF and VSD (p &lt; 0.001 for all). These results are the first to demonstrate that thiol/disulphide homeostasis and nitric oxide are associated with TOF and VSD in children.

Assessment of dental caries and salivary nitric oxide levels in children with dyspepsia

BackgroundThe increase in nitric oxide (NO) levels in the oral cavity and saliva have been associated with various oral diseases; however, the gastro-salivary interaction of NO remains controversial. Thus, the aim of this study was to determine and compare salivary NO levels of dyspeptic and non-dyspeptic healthy children and to conduct an evaluation of its association with dental caries.MethodsSeventy children with dyspepsia (dyspeptic group) and 30 children without any gastrointestinal complaints (control group) were included in the study. Two biopsies from the gastric tissues were collected from dyspeptic children for histopathologic examination. Oral examination involved the assessment of dental caries, gingival index, plaque index, buffering capacity, salivary flow rate and pH. Salivary Streptococcus mutans (S. mutans) and Lactobacilli sp. counts were performed by commercial kits. For the comparison of the normal distribution between dyspeptic and control groups, Student t-test and for the comparison of the non-normal distribution, Kruskal-Wallis and Mann-Whitney-U tests were used. Chi-square test was used for comparison of qualitative data and the Pearson correlation test was used to evaluate the association between certain variables. Significance was assessed at p < 0.05 level.ResultsHelicobacter pylori (H.pylori) were found in gastric biopsies of 84.2% (59/70) of the dyspeptic children. While the mean salivary NO values did not differ significantly between gastric H.pylori positive, negative and control groups, the salivary NO level of the dyspeptic group (213.7 ± 51.68 μmol/dL) was found to be significantly higher than the control group (185.7 ± 16.66 μmol/dL). No significant relationship was found between the mean salivary NO values, DMFT/dmft numbers and other oral parameters.ConclusionsThe association of dental caries and salivary NO levels could not be considered specific in the current study. Although there were no statistically significant differences between salivary NO levels of gastric H.pylori positive, gastric H.pylori negative and control groups, greater salivary NO levels among dyspeptic children compared with the control group demonstrated that the concentration of NO in the saliva could be used as a biological marker in dyspepsia, which could lead to the improvement of more specified, uncomplicated and susceptible methods for analysis.

Decreased serum level of nitric oxide in children with excessive body weight

Nitric oxide (NO) is an important mediator involved in vascular homeostasis. Changes in NO level are considered to be associated with obesity and its clinical consequences. Previous studies on NO levels in obese children provided inconclusive results, so this issue requires clarification. One of the main goals of this study was to assess whether childhood excessive body weight (EBW) is associated with changes in serum NO level and whether features like age and gender are linked to NO levels in selected groups. In the present study, the serum NO levels were compared in 43 children with EBW and 37 ageand gender-matched children with normal weight. Moreover, in both groups, body measurements and various clinical parameters, including the serum concentrations of arginine (Arg), a precursor of NO, were determined. The mean serum NO level in EBW group (8.7 ±3.1 μmol/L) was significantly lower than in normal weight group (22.2 ±11.5 μmol/L). However, the serum Arg concentrations were higher in EBW children than in controls. Serum asymmetric dimethylarginine (ADMA) levels were higher in EBW group and inversely correlated with serum NO. The EBW female subgroup was characterized by slightly lower level of NO than the EBW male subgroup. There were no significant changes in serum NO level among different age subgroups in both groups. Our results revealed that EBW in children is associated with significantly decreased level of serum NO. The decreased serum NO level in EBW children is not a result of depleted Arg in the blood. Asymmetric dimethylarginine may at least partially contribute to decreased NO levels in children with EBW. A decreased level of NO could be a potential early marker of the risk of cardiovascular disorders developing in children with EBW.

Nasal nitric oxide in sleep-disordered breathing in children.

Inflammation plays a role in the pathogenesis and consequences of sleep-disordered breathing (SDB). The nasal mucosa and paranasal sinuses produce high levels of nitric oxide (NO). In asthma, exhaled NO is a marker of airway inflammation. There is only limited information whether nasal NO (nNO) accompanies also chronic upper airway obstruction, specifically, SDB. The objective of this study was to investigate nNO levels in children with SDB in comparison to healthy non-snoring children. Nasal NO was measured in children who underwent overnight polysomnographic studies due to habitual snoring and suspected SDB and in healthy non-snoring controls. One hundred and eleven children participated in the study: 28 with obstructive sleep apnea (OSA), 60 with primary snoring (PS), and 23 controls. Nasal NO levels were significantly higher in children with OSA and PS compared to controls (867.4 ± 371.5, 902.0 ± 330.9, 644.1 ± 166.5 ppb, respectively, p = 0.047). No difference was observed between children with OSA and PS. No correlations were found between nNO levels and any of the PSG variables, nor with age, BMI percentile or tonsils size. Compared to healthy controls, nNO is increased in children with SDB, but it is not correlated with disease severity. This is probably due to the local mechanical processes and snoring.

Estimation of salivary nitric oxide levels in children with congenital heart diseases

Introduction:Oral health problems, especially dental caries are known to be common in children with severe heart disease, especially at early ages. The role of nitric oxide (NO) in protection against oral diseases owing to its strong antimicrobial action has been a topic of interest.Objective:The current study was carried out to estimate the NO levels in the salivary samples of children diagnosed with congenital heart diseases (CHDs) and to determine whether salivary NO can serve as a potential biomarker for the evaluation of dental caries-risk.Methodology:This prospective study was performed on 50 children suffering from CHDs who reported to the department of pediatrics and the levels were compared with those of 50 healthy caries-free children. NO levels in the collected salivary levels were determined spectrophotometrically using the Griess reaction method.Results:Subjects between the age group of 6 and 12 years had maximum decayed teeth (20.95%). The mean NO level in children in study group (60.63) was decreased in comparison to the control group (132.40), which was statistically significant (P value of 0.001). The mean age of the subjects in the study group was 7.24 and the salivary NO levels decreased with age, which was statistically significant.Conclusion:Children are suffering from medically compromising conditions such as CHDs are at a higher risk for dental caries and decreased salivary NO levels in these patients may prove as a critical indicator of the same. Saliva can be further utilized as an important biomarker for the determination of the relationship between salivary NO levels and development of dental caries.

Clinical application of nasal nitric oxide measurement in pediatric airway diseases.

Nitric oxide plays an important role in several physiological and pathophysiological processes in the respiratory tract. Different ways to measure nasal nitric oxide levels in children are currently available. The possibility of obtaining nasal nitric oxide measurement from relatively young children, combined with the availability of portable devices that can be used even in the office setting, opens new perspectives for nasal nitric oxide analysis in the pediatric daily practice. This review presents a synopsis about the current clinical applications of nasal nitric oxide measurement in the pediatric clinical practice. A total of 3,775 articles on the topic were identified, of which 883 duplicates were removed, and 2,803 were excluded based on review of titles and abstracts. Eighty-nine full text articles were assessed for eligibility and 32 additional articles were obtained from the reference lists of the retrieved studies. Since very low nasal nitric oxide levels are found in the majority of patients with primary ciliary dyskinesia, most publications support a central role for nasal nitric oxide to screen the disease, and indicate that it is a very helpful first-line tool in the real-life work-up in all age groups. Decreased nasal nitric oxide concentration is also typical of cystic fibrosis, even though nasal nitric oxide is not as low as in primary ciliary dyskinesia. In other upper airway disorders such as allergic rhinitis, rhinosinusitis, nasal polyposis, and adenoidal hypertrophy, clinical utility of nasal nitric oxide is still critically questioned and remains to be established. Since nNO determination is flow dependent, a general consensus from the major investigators in this area is highly desirable so that future studies will be performed with the same flow rate. A shared nNO methodology will enable to overcome the challenges that lie ahead in incorporating nNO measurement into the mainstream clinical setting of pediatric airway diseases.

Nasal Nitric Oxide Levels and Nasal Polyposis in Children and Adolescents With Cystic Fibrosis

The counterintuitive decrease of exhaled nitric oxide (NO) levels in a severe inflammatory disorder like cystic fibrosis (CF) is only scarcely understood. Because NO is important in a variety of regulatory processes in the lung, including host defense, inflammation, and bronchomotor control, it is necessary to search for clarifying mechanisms. To explore whether fractional exhaled NO (FENO) and nasal NO (nNO) levels are associated with CF genotype, nutritional status, presence of nasal polyps, pulmonary function, and airway colonization with Staphylococcus aureus and Pseudomonas aeruginosa in children with CF, and to investigate the effect of functional endoscopic sinus surgery (FESS) on FENO and nNO levels in children with CF and persistent sinonasal disease. Cross-sectional study (association with NO) and prospective study (effect of FESS on NO) in a tertiary care referral center. Patients included 95 children with CF in clinically stable condition at routine annual multidisciplinary examination, 13 of whom were referred for a FESS procedure. Functional endoscopic sinus surgery in children with CF and persistent sinonasal disease. Body mass index (BMI), FENO and nNO levels, results of flexible nasal endoscopy, pulmonary function tests (forced expiratory volume in 1 second and forced vital capacity), and airway cultures. Children with nasal polyposis have significantly lower nNO levels than those without polyposis (median, 53 vs 140 parts per billion; P = .001); these values are negatively associated with colonization with S aureus (β = -.22; P = .04). After FESS, nNO values increase significantly, although not to normal levels. In children with CF, the presence of nasal polyps is associated with significantly lower nNO levels than in children without nasal polyps. After FESS for nasal polyposis, nNO levels increase significantly, but not to normal levels. Low nNO levels are associated with S aureus colonization in the oropharynx and lower airways.

Age-stratified comparison of large and peripheral airway/alveolar nitric oxide levels in children and young adults

Age-stratified comparison of large and peripheral airway/alveolar nitric oxide levels in children and young adults

Genetic and epigenetic variations in inducible nitric oxide synthase promoter, particulate pollution, and exhaled nitric oxide levels in children

Inducible nitric oxide synthase (iNOS; encoded by nitric oxide synthase isoform 2 [NOS2]) is the major enzyme for nitric oxide synthesis in airways. As such, measurement of fractional concentration of exhaled nitric oxide (Feno) provides an in vivo assessment of iNOS activity. Short-term exposure to air pollution, haplotypes, and DNA methylation in the NOS2 promoter has been associated independently with iNOS expression, Feno levels, or both. We aimed to examine the effects of ambient air pollutants, NOS2 promoter haplotypes, and NOS2 promoter methylation on Feno levels in children. We selected 940 participants in the Children's Health Study who provided buccal samples and had undergone Feno measurement on the same day. DNA methylation was measured with a bisulfite-PCR Pyrosequencing assay. Seven single nucleotide polymorphisms captured the haplotype diversity in the NOS2 promoter. Average particulate matter with an aerodynamic diameter of 2.5 μm or less (PM(2.5)) and 10 μm (PM(10)) or less and ozone and nitrogen dioxide levels 7 days before Feno measurement were estimated based on air pollution data obtained at central monitoring sites. We found interrelated effects of PM(2.5), NOS2 promoter haplotypes, and iNOS methylation on Feno levels. Increased 7-day average PM(2.5) exposure was associated with lower iNOS methylation (P = .01). NOS2 promoter haplotypes were globally associated with NOS2 promoter methylation (P = 6.2 × 10(-8)). There was interaction among 1 common promoter haplotype, iNOS methylation level, and PM(2.5) exposure on Feno levels (P(interaction) = .00007). Promoter variants in NOS2 and short-term PM(2.5) exposure affect iNOS methylation. This is one of the first studies showing contributions of genetic and epigenetic variations in air pollution-mediated phenotype expression.

Genetic Variations in Nitric Oxide Synthase and Arginase Influence Exhaled Nitric Oxide Levels in Children

MT Salam, TM Bastain, EB Rappaport. Allergy. 2011;66(3):412–419 Elevated fractional exhaled nitric oxide (FeNO) has been shown to be a sensitive biomarker for airway inflammation in children with asthma. This study examined whether a relationship could be demonstrated between genetic variants in nitric-oxide synthase and arginase genes and FeNO in asthma. Subjects aged 5 to 7 years were recruited from 13 Southern California communities for a Children's …

It’s time to rethink mite allergen avoidance

The role of allergen exposure in the etiology of allergic sensitization and asthma is complex. Advice on strategies to avoid domestic allergens remains contentious because trials of interventions aimed to prevent asthma or reduce symptoms have often failed to demonstrate benefits. Asthma management guidelines differ widely in their recommendations, while Web-based information often claims benefits associated with products. In this rostrum we argue that although many factors have a role in both the etiology and the exacerbation of asthma, allergen exposure probably remains an important contributor to the manifestations of the disease. Currently, there is no evidence-based framework for effective domestic allergen avoidance interventions to reduce chronic aeroallergen exposure. The development of an effective approach to allergen avoidance requires a better understanding of (a) the physical nature of chronic aeroallergen exposure and methods for measuring and reducing this, (b) the interaction between allergen exposure and innate immune modulators at different disease stages, and (c) markers enabling the identification of individuals who would benefit from this. The strategic risk of overemphasizing other novel mechanisms and approaches to asthma management is that we will prematurely abandon and fail to improve an existing approach that could have a significant impact on the development, progression, and symptoms of the disease.

Allergen exposure modifies the relation of sensitization to fraction of exhaled nitric oxide levels in children at risk for allergy and asthma

Studies on airway inflammation, measured as fraction of exhaled nitric oxide (FENO), have focused on its relation to control of asthma, but the contribution of allergen exposure to the increase in FENO levels is unknown. We evaluated (1) whether FENO levels were increased in children with allergic sensitization or asthma; (2) whether specific allergen exposure increased FENO levels in sensitized, but not unsensitized, children; and (3) whether sedentary behavior increased FENO levels independent of allergen exposures. At age 12 years, in a birth cohort of children with a parental history of allergy or asthma, we measured bed dust allergen (dust mite, cat, and cockroach) by means of ELISA, specific allergic sensitization primarily based on specific IgE levels, and respiratory disease (current asthma, rhinitis, and wheeze) and hours of television viewing/video game playing by means of questionnaire. Children performed spirometric maneuvers before and after bronchodilator responses and had FENO levels measured by using electrochemical detection methods (NIOX MINO). FENO levels were increased in children with current asthma (32.2 ppb), wheeze (27.0 ppb), or rhinitis (23.2 ppb) compared with subjects without these respective symptoms/diagnoses (16.4-16.6 ppb, P < .005 for all comparisons). Allergic sensitization to indoor allergens (cat, dog, and dust mite) predicted higher FENO levels and explained one third of the variability in FENO levels. FENO levels were highest in children both sensitized and exposed to dust mite. Greater than 10 hours of weekday television viewing was associated with a 0.64-log increase in FENO levels after controlling for indoor allergen exposure, body mass index, and allergic sensitization. Allergen exposures and sedentary behavior (television viewing/video game playing) might increase airway inflammation, which was measured as the FENO.

Exhaled Nitric Oxide Levels in Children with Chronic Adenotonsillar Disease

Exhaled nitric oxide (eNO) is a highly reactive biological mediator that has recently been associated with chronic tonsillar disease in adults, but there are no published data concerning eNO levels in their pediatric counterparts. The aim of this study is to measure mean eNO levels in children with chronic adenotonsillitis or adenotonsillar hypertrophy, and assess the effects of potential confounding factors. Children aged 3-17 years were divided into three groups (chronic adenotonsillitis, adenotonsillar hypertrophy and controls). Their eNO levels were measured in accordance with the international guidelines, and their other clinical and anamnestic characteristics were recorded. The mean eNO level in the children with chronic adenotonsillitis was slightly higher than that in the other groups, but there was no statistically significant between-group difference. Age (p=0.009), allergy (p=0.05) and body mass index (p=0.03), but not the mean grade of adenoidal or tonsil hypertrophy, were all statistically related to mean eNO levels. These preliminary results indicate the lack of an increase in mean eNO levels in children with chronic adenotonsillar disease, with no substantial difference between children with chronic adenotonsillitis and those with adenotonsillar hypertrophy.

Genetic variations in nitric oxide synthase and arginase influence exhaled nitric oxide levels in children

Exhaled nitric oxide (FeNO) is a biomarker of airway inflammation. In the nitric oxide (NO) synthesis pathway, nitric oxide synthases (encoded by NOS1, NOS2A, and NOS3) and arginases (encoded by ARG1 and ARG2) compete for L-arginine. Although FeNO levels are higher in children with asthma/allergy, influence of these conditions on the relationships between variations in these genes and FeNO remains unknown. The aims of the study were to evaluate the role of genetic variations in nitric oxide synthases and arginases on FeNO in children and to assess the influence of asthma and respiratory allergy on these genetic associations. Among children (6-11 years) who participated in the southern California Children's Health Study, variations in these five genetic loci were characterized by tagSNPs. FeNO was measured in two consecutive years (N = 2298 and 2515 in Years 1 and 2, respectively). Repeated measures analysis of variance was used to evaluate the associations between these genetic variants and FeNO. Sequence variations in the NOS2A and ARG2 loci were globally associated with FeNO (P = 0.0002 and 0.01, respectively). The ARG2 association was tagged by intronic variant rs3742879 with stronger association with FeNO in asthmatic children (P-interaction = 0.01). The association of a NOS2A promoter haplotype with FeNO varied significantly by rs3742879 genotypes and by asthma. Variants in the NO synthesis pathway genes jointly contribute to differences in FeNO concentrations. Some of these genetic influences were stronger in children with asthma. Further studies are required to confirm our findings.

Nasal nitric oxide in children with adenoidal hypertrophy: A preliminary study

Objective Nasal nitric oxide, a mediator involved in upper airway inflammation, is impaired in children with allergic rhinitis and rhinosinusitis. Normal values are 200–450 parts per billion, but no data are available concerning its levels in children with adenoidal obstruction, predisposing to chronic nasosinusal inflammation. This study aimed to: (1) measure nasal nitric oxide levels in non-allergic children with adenoidal hypertrophy and (2) assess its possible relationship with the degree of adenoidal hypertrophy and other variable (gender, age, body max index, passive smoking exposure, recurrent acute otitis media, recurrent respiratory infections, and hypertrophy of nasal turbinates). Methods Eighty-one children with suspected adenoidal hypertrophy underwent nasal fibroendoscopy to assess the degree of adenoidal hypertrophy, and nasal nitric oxide on-line measurements by means of a dedicated chemiluminescence analyser. Results Nasal nitric oxide was successfully measured in 35 patients, most of whom had levels >450 parts per billion; the values were significantly higher ( p = 0.031) in children with non-obstructive adenoids. There was no significant correlation with any other variable. Conclusions Preliminary data show above-normal nasal nitric oxide levels in children with adenoidal hypertrophy, especially those with non-obstructive adenoids. This suggests nitric oxide involvement in recurrent nasopharyngeal inflammation due to adenoidal hypertrophy.

Serum and urine nitric oxide levels in children with Henoch–Schonlein purpura during activity and remission: a study from North India

The objective of this study is to compare serum and urine reactive nitrogen intermediates (RNI) and citrulline levels in children with Henoch-Schonlein purpura (HSP) during activity and remission. The study group consisted of 14 children with HSP. We measured serum and urine RNI and citrulline levels by spectrophotometry in the active phase of the disease and then during remission. Serum RNI levels were 303.95 +/- 221.44 nmol/ml in children with active HSP and 72.57 +/- 26.56 nmol/ml during remission, the differences being statistically significant (P = 0.002). Mean urine RNI levels in children with active HSP were significantly higher than that seen during remission (3.25 +/- 1.80 vs. 1.68 +/- 0.65 nmol/ml; P = 0.003). Similarly, serum citrulline levels during disease activity were 790.65 +/- 707.87 nmol/ml as compared to 281.49 +/- 307.29 nmol/ml at the time of remission, the differences being statistically significant (P = 0.002). Mean urine citrulline levels in children with active disease was 1,969.94 +/- 1655.42 nmol/ml as compared to 1,099.34 +/- 955.82 nmol/ml in children with remission, (P = 0.007). Serum and urine RNI and citrulline levels were significantly higher during the acute phase of HSP as compared to the levels obtained during the phase of disease remission. These findings suggest that nitric oxide may perhaps have a role in the pathogenesis of HSP. Further, these laboratory parameters could be of value in monitoring disease activity. To the best of our knowledge, this study is the most comprehensive work published on the subject so far. Our findings, however, need to be confirmed on a larger study sample before firm conclusions can be drawn.

Serum and urine nitric oxide levels in children with Henoch-Schonlein Purpura during activity and remission – a study from North India

The objective of this study is to compare serum and urine reactive nitrogen intermediates (RNI) and citrulline levels in children with Henoch-Schonlein purpura (HSP) during activity and remission. The study group consisted of 14 children with HSP. We measured serum and urine RNI and citrulline levels by spectrophotometry in the active phase of the disease and then during remission. Serum RNI levels were 303.95 ± 221.44 nmol/ml in children with active HSP and 72.57 ± 26.56 nmol/ml during remission, the differences being statistically significant (P = 0.002). Mean urine RNI levels in children with active HSP were significantly higher than that seen during remission (3.25 ± 1.80 vs. 1.68 ± 0.65 nmol/ml; P = 0.003). Similarly, serum citrulline levels during disease activity were 790.65 ± 707.87 nmol/ml as compared to 281.49 ± 307.29 nmol/ml at the time of remission, the differences being statistically significant (P = 0.002). Mean urine citrulline levels in children with active disease was 1,969.94 ± 1655.42 nmol/ml as compared to 1,099.34 ± 955.82 nmol/ml in children with remission, (P = 0.007). Serum and urine RNI and citrulline levels were significantly higher during the acute phase of HSP as compared to the levels obtained during the phase of disease remission. These findings suggest that nitric oxide may perhaps have a role in the pathogenesis of HSP. Further, these laboratory parameters could be of value in monitoring disease activity. To the best of our knowledge, this study is the most comprehensive work published on the subject so far. Our findings, however, need to be confirmed on a larger study sample before firm conclusions can be drawn.

The effect of acute pain crisis on exhaled nitric oxide levels in children with sickle cell disease

Exhaled nitric oxide (FE(NO)) has been shown to be decreased in children with sickle cell disease. We sought to evaluate the effect of sickle cell vaso-occlusive crisis (VOC) on FE(NO) levels. We measured FE(NO) levels in 42 children with sickle cell disease, 29 in their baseline health and 13 during an acute VOC. There was no difference in FE(NO) levels between children at baseline (15.12 +/- 9.32 ppb) and those during an acute VOC (15.68 +/- 7.26 ppb; P = 0.794). FE(NO) is not a useful marker of acute VOC in children with sickle cell disease.