human
***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: Background  Exhaled breath condensate ( EBC )  is a non-invasive method to assess airway inflammation and oxidative stress and may be useful in the assessment of childhood asthma . Methods  Exhaled 8-isoprostane , a stable marker of oxidative stress , was measured in EBC , in children ( 5–17 years ) with asthma ( 13 steroid-naïve and 12 inhaled steroid-treated ) and 11 healthy control . Results Mean exhaled 8-isoprostane concentration was significantly elevated in steroid-naïve asthmatic children compared to healthy children 9.3 ( SEM 1.7 ) vs. 3.8 ( 0.6 ) pg/ml , p < 0.01 . Children on inhaled steroids also had significantly higher 8-isoprostane levels than those of normal subjects 6.7 ( 0.7 ) vs. 3.8 ( 0.6 ) pg/ml , p < 0.01 . Steroid-naïve asthmatics had higher exhaled nitric oxide ( eNO ) than those of controls 28.5 ( 4.7 ) vs. 12.6 ( 1.5 ) ppb , p < 0.01 . eNO in steroid-treated asthmatics was similar to control subjects 27.5(8.8 ) vs. 12.6(1.5 ) ppb . Exhaled 8-isoprostane did not correlate with duration of asthma , dose of inhaled steroids or eNO . Conclusion We conclude that 8-isoprostane is elevated in asthmatic children , indicating increased oxidative stress , and that this does not appear to be normalized by inhaled steroid therapy . This suggests that 8-isoprostane is a useful non-invasive measurement of oxidative stress in children and that antioxidant therapy may be useful in the future Background The role of leukotriene ( LT ) B4 , a potent inflammatory mediator , in atopic asthmatic and atopic nonasthmatic children is largely unknown . The lack of a gold st and ard technique for measuring LTB4 in exhaled breath condensate ( EBC ) has hampered its quantitative assessment in this biological fluid . We sought to measure LTB4 in EBC in atopic asthmatic children and atopic nonasthmatic children .  Exhaled nitric oxide ( NO ) was measured as an independent marker of airway inflammation . Methods Fifteen healthy children , 20 atopic nonasthmatic children , 25 steroid-naïve atopic asthmatic children , and 22 atopic asthmatic children receiving inhaled corticosteroids were studied . The study design was of cross-sectional type . Exhaled LTB4 concentrations were measured using liquid chromatography/mass spectrometry-mass spectrometry ( LC/MS/MS ) with a triple quadrupole mass spectrometer . Exhaled NO  was measured by chemiluminescence with a single breath on-line method . LTB4 values were expressed as the total amount ( in pg ) of eicosanoid expired in the 15-minute breath test . Kruskal-Wallis test was used to compare groups . Results Compared with healthy children [ 87.5 ( 82.5–102.5 ) pg , median and interquartile range ] , exhaled LTB4 was increased in steroid-naïve atopic asthmatic [ 255.1 ( 175.0–314.7 ) pg , p < 0.001 ] , but not in atopic nonasthmatic children [ 96.5 ( 87.3–102.5 ) pg , p = 0.59 ) ] . Asthmatic children who were receiving inhaled corticosteroids had lower concentrations of exhaled LTB4 than steroid-naïve asthmatics [ 125.0 ( 25.0–245.0 ) pg vs 255.1 ( 175.0–314.7 ) pg , p < 0.01 , respectively ] . Exhaled NO was higher in atopic nonasthmatic children [ 16.2 ( 13.5–22.4 ) ppb , p < 0.05 ] and , to a greater extent , in atopic steroid-naïve asthmatic children [ 37.0 ( 31.7–57.6 ) ppb , p < 0.001 ] than in healthy children [ 8.3 ( 6.1–9.9 ) ppb ] . Compared with steroid-naïve asthmatic children , exhaled NO levels were reduced in asthmatic children who were receiving inhaled corticosteroids [ 15.9 ( 11.5–31.7 ) ppb , p < 0.01 ] . Conclusion In contrast to exhaled NO concentrations , exhaled LTB4 values are selectively elevated in steroid-naïve atopic asthmatic children , but not in atopic nonasthmatic children . Although placebo control studies are warranted , inhaled corticosteroids seem to reduce exhaled LTB4 in asthmatic children . LC/MS/MS analysis of exhaled LTB4 might provide a non-invasive , sensitive , and quantitative method for airway inflammation assessment in asthmatic children Asthmatic airways are characterised by enhanced oxidative stress , which can be studied by measuring biomarkers , such as 8-isoprostane . The aims of the present study were : 1 ) to measure the concentrations of 8-isoprostane in exhaled breath condensate ( EBC ) and urine of children with problematic and well-controlled asthma ; 2 ) to compare the concentrations of 8-isoprostane measured by gas chromatographic/negative ion chemical ionisation mass spectrometry ( GC/NICI-MS ) and by an enzymatic immunoassay ( EIA ) . We recruited 20 asthmatic allergic children , 13 with well-controlled asthma and seven with problematic asthma . They underwent exhaled nitric oxide measurements and spirometry , and both EBC and urine sample s were collected . 8-isoprostane was measured in EBC by GC/NICI-MS and EIA . 8-isoprostane concentrations in EBC were significantly higher in children with problematic asthma than in children with well-controlled asthma ( p = 0.01 ) . An acceptable reproducibility emerged between GC/NICI-MS and EIA ( coefficient of reproducibility 11.5 pg·mL−1 ) . 8-isoprostane levels measured in urine did not correlate with those measured in EBC . We showed that 8-isoprostane in EBC was significantly increased in children with problematic asthma , suggesting a role for oxidative stress in this asthma phenotype . In addition we found an acceptable reproducibility of EIA compared to GC/NICI-MS , even if the latter method had higher accuracy BACKGROUND Cysteinyl-leukotrienes ( cys-LTs ) and 8-isoprostane are biomarkers of airway inflammation and oxidative stress . OBJECTIVE The aim of this study was to evaluate  cys-LT and 8-isoprostane levels in exhaled breath condensate ( EBC ) of children with different degrees of asthma severity . METHODS EBC was collected from 14 steroid-naive children with mild persistent asthma , 13 children with stable mild- to-moderate persistent asthma treated with inhaled corticosteroids ( ICS ) , 9 ICS-treated children with unstable asthma , and 19 healthy children . RESULTS In the three groups of asthmatic children , EBC concentrations of cys-LTs and 8-isoprostane were significantly higher than in control children ( steroid-naive asthmatic children : cys-LTs median , 10.8 pg/mL , P < .001 , 8-isoprostane , 16.2 pg/mL , P < .001 ; ICS-treated stable asthmatic children : cys-LTs , 12.7 pg/mL , P < .001 , 8-isoprostane , 18.1 pg/mL , P < .001 ; children with unstable asthma : cys-LTs , 106.0 pg/mL , P < .01 , 8-isoprostane , 29.7 pg/mL , P < .01 ; control children : cys-LTs , 4.3 pg/mL , 8-isoprostane , 3.5 pg/mL ) . Cys-LT levels were higher in children with unstable asthma than in the other two asthmatic groups ( P < .05 ) . FE(NO ) levels were significantly higher in steroid-naive and in children with unstable asthma compared with ICS-treated children with stable asthma ( P < .01 ) . CONCLUSIONS Our study shows that EBC cys-LTs and 8-isoprostane concentrations are higher in asthmatic children than in healthy control children , with scattered values in patients with unstable asthma . These findings suggest that EBC eicosanoid measurement may have useful clinical implication s for investigating phenotype differences among asthmatic patients Chronic airway inflammation in children with asthma might be present even in the absence of pathological lung function tests and is known to increase the risk of permanent pulmonary damage . Thus , we aim ed at investigating to what extent inflammatory markers such as leukotrienes ( LTs ) in exhaled breath condensate ( EBC ) or fractional exhaled nitric oxide ( FE(NO ) ) reflect therapeutic effects in these patients . Fifty steroid-naive patients ( aged 8.8 + /- 2.7 years ) were included in the study . EBC was collected before and 6 months after therapy with inhaled corticosteroids .  LTs were determined by using commercially available ELISA . In addition , FE(NO ) was measured by means of a chemiluminescence analyzer . Conventional lung function testing was performed revealing vital capacity , forced expiratory volume , maximum expiratory flow , and specific resistance . In EBC , LTE(4 ) but not LTB(4 ) levels significantly decreased after steroid therapy from 45.3 + /- 36.0 pg/mL to 17.2 + /- 11.4 pg/mL ( p < 0.0001 ) concomitant with a slight , but significant improvement of lung function parameters . Mean FE(NO ) also indicated therapeutic success ; however , in 20 of 50 patients , exhaled NO concentrations were higher after therapy . These findings suggest that LTE(4 ) in breath condensate may be helpful in latent inflammatory activity in the bronchial mucosa in children with asthma RATIONALE  Exhaled breath condensate pH ( EBC-pH )  may be useful noninvasive marker for evaluation of patients with asthma . OBJECTIVES To investigate the relationship between EBC-pH and symptoms suggestive of childhood asthma in an epidemiologic setting and examine its relation to lung function , airway hyperresponsiveness ( AHR ) , and airway inflammation . METHODS Within the context of a prospect i ve population -based birth cohort , EBC was collected from 630 children at age 8 yr using the  RTube ( pH measured after deaeration with argon ) . Lung function was measured by spirometry ( FEV1 ; n = 521 ) and plethysmography ( sRaw ; n = 567 ) , and AHR by methacholine challenge ( n = 498 ) . Airway inflammation was assessed using exhaled nitric oxide ( eNO ; n = 305 ) . RESULTS EBC-pH values ranged widely ( 4.40 - 8.29 ) , and did not differ between 54 children with parentally reported asthma and 562 nonasthmatic subjects ( median [ interquartile range ] : 7.75 [ 7.45 - 7.85 ] vs. 7.77 [ 7.59 - 7.87 ] ; p = 0.35 ) . There was a trend for lower EBC-pH among current wheezers ( n = 98 ; 7.72 [ 7.50 - 7.83 ] ) compared with nonwheezers ( n = 532 ; 7.77 [ 7.60 - 7.87 ] ; p = 0.07 ) . Wheeze frequency , severity , and use of antiasthma medication were not associated with EBC-pH. There was no consistent association between EBC-pH and lung function , airway reactivity , and airway inflammation ( FEV1 , sRaw , PD20 methacholine , or eNO ) . There was no significant difference in EBC-pH between current wheezers receiving asthma medication who had positive methacholine challenge compared with children without any of these features . CONCLUSIONS In the epidemiologic setting , EBC-pH does not differ between children with and without parentally reported symptoms suggestive of asthma . We found no consistent association between EBC-pH and lung function , AHR , and airway inflammation in this sample from the general population 
    Output:
    
agent
***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: Background  Exhaled breath condensate ( EBC )  is a non-invasive method to assess airway inflammation and oxidative stress and may be useful in the assessment of childhood asthma . Methods  Exhaled 8-isoprostane , a stable marker of oxidative stress , was measured in EBC , in children ( 5–17 years ) with asthma ( 13 steroid-naïve and 12 inhaled steroid-treated ) and 11 healthy control . Results Mean exhaled 8-isoprostane concentration was significantly elevated in steroid-naïve asthmatic children compared to healthy children 9.3 ( SEM 1.7 ) vs. 3.8 ( 0.6 ) pg/ml , p < 0.01 . Children on inhaled steroids also had significantly higher 8-isoprostane levels than those of normal subjects 6.7 ( 0.7 ) vs. 3.8 ( 0.6 ) pg/ml , p < 0.01 . Steroid-naïve asthmatics had higher exhaled nitric oxide ( eNO ) than those of controls 28.5 ( 4.7 ) vs. 12.6 ( 1.5 ) ppb , p < 0.01 . eNO in steroid-treated asthmatics was similar to control subjects 27.5(8.8 ) vs. 12.6(1.5 ) ppb . Exhaled 8-isoprostane did not correlate with duration of asthma , dose of inhaled steroids or eNO . Conclusion We conclude that 8-isoprostane is elevated in asthmatic children , indicating increased oxidative stress , and that this does not appear to be normalized by inhaled steroid therapy . This suggests that 8-isoprostane is a useful non-invasive measurement of oxidative stress in children and that antioxidant therapy may be useful in the future Background The role of leukotriene ( LT ) B4 , a potent inflammatory mediator , in atopic asthmatic and atopic nonasthmatic children is largely unknown . The lack of a gold st and ard technique for measuring LTB4 in exhaled breath condensate ( EBC ) has hampered its quantitative assessment in this biological fluid . We sought to measure LTB4 in EBC in atopic asthmatic children and atopic nonasthmatic children .  Exhaled nitric oxide ( NO ) was measured as an independent marker of airway inflammation . Methods Fifteen healthy children , 20 atopic nonasthmatic children , 25 steroid-naïve atopic asthmatic children , and 22 atopic asthmatic children receiving inhaled corticosteroids were studied . The study design was of cross-sectional type . Exhaled LTB4 concentrations were measured using liquid chromatography/mass spectrometry-mass spectrometry ( LC/MS/MS ) with a triple quadrupole mass spectrometer . Exhaled NO  was measured by chemiluminescence with a single breath on-line method . LTB4 values were expressed as the total amount ( in pg ) of eicosanoid expired in the 15-minute breath test . Kruskal-Wallis test was used to compare groups . Results Compared with healthy children [ 87.5 ( 82.5–102.5 ) pg , median and interquartile range ] , exhaled LTB4 was increased in steroid-naïve atopic asthmatic [ 255.1 ( 175.0–314.7 ) pg , p < 0.001 ] , but not in atopic nonasthmatic children [ 96.5 ( 87.3–102.5 ) pg , p = 0.59 ) ] . Asthmatic children who were receiving inhaled corticosteroids had lower concentrations of exhaled LTB4 than steroid-naïve asthmatics [ 125.0 ( 25.0–245.0 ) pg vs 255.1 ( 175.0–314.7 ) pg , p < 0.01 , respectively ] . Exhaled NO was higher in atopic nonasthmatic children [ 16.2 ( 13.5–22.4 ) ppb , p < 0.05 ] and , to a greater extent , in atopic steroid-naïve asthmatic children [ 37.0 ( 31.7–57.6 ) ppb , p < 0.001 ] than in healthy children [ 8.3 ( 6.1–9.9 ) ppb ] . Compared with steroid-naïve asthmatic children , exhaled NO levels were reduced in asthmatic children who were receiving inhaled corticosteroids [ 15.9 ( 11.5–31.7 ) ppb , p < 0.01 ] . Conclusion In contrast to exhaled NO concentrations , exhaled LTB4 values are selectively elevated in steroid-naïve atopic asthmatic children , but not in atopic nonasthmatic children . Although placebo control studies are warranted , inhaled corticosteroids seem to reduce exhaled LTB4 in asthmatic children . LC/MS/MS analysis of exhaled LTB4 might provide a non-invasive , sensitive , and quantitative method for airway inflammation assessment in asthmatic children Asthmatic airways are characterised by enhanced oxidative stress , which can be studied by measuring biomarkers , such as 8-isoprostane . The aims of the present study were : 1 ) to measure the concentrations of 8-isoprostane in exhaled breath condensate ( EBC ) and urine of children with problematic and well-controlled asthma ; 2 ) to compare the concentrations of 8-isoprostane measured by gas chromatographic/negative ion chemical ionisation mass spectrometry ( GC/NICI-MS ) and by an enzymatic immunoassay ( EIA ) . We recruited 20 asthmatic allergic children , 13 with well-controlled asthma and seven with problematic asthma . They underwent exhaled nitric oxide measurements and spirometry , and both EBC and urine sample s were collected . 8-isoprostane was measured in EBC by GC/NICI-MS and EIA . 8-isoprostane concentrations in EBC were significantly higher in children with problematic asthma than in children with well-controlled asthma ( p = 0.01 ) . An acceptable reproducibility emerged between GC/NICI-MS and EIA ( coefficient of reproducibility 11.5 pg·mL−1 ) . 8-isoprostane levels measured in urine did not correlate with those measured in EBC . We showed that 8-isoprostane in EBC was significantly increased in children with problematic asthma , suggesting a role for oxidative stress in this asthma phenotype . In addition we found an acceptable reproducibility of EIA compared to GC/NICI-MS , even if the latter method had higher accuracy BACKGROUND Cysteinyl-leukotrienes ( cys-LTs ) and 8-isoprostane are biomarkers of airway inflammation and oxidative stress . OBJECTIVE The aim of this study was to evaluate  cys-LT and 8-isoprostane levels in exhaled breath condensate ( EBC ) of children with different degrees of asthma severity . METHODS EBC was collected from 14 steroid-naive children with mild persistent asthma , 13 children with stable mild- to-moderate persistent asthma treated with inhaled corticosteroids ( ICS ) , 9 ICS-treated children with unstable asthma , and 19 healthy children . RESULTS In the three groups of asthmatic children , EBC concentrations of cys-LTs and 8-isoprostane were significantly higher than in control children ( steroid-naive asthmatic children : cys-LTs median , 10.8 pg/mL , P < .001 , 8-isoprostane , 16.2 pg/mL , P < .001 ; ICS-treated stable asthmatic children : cys-LTs , 12.7 pg/mL , P < .001 , 8-isoprostane , 18.1 pg/mL , P < .001 ; children with unstable asthma : cys-LTs , 106.0 pg/mL , P < .01 , 8-isoprostane , 29.7 pg/mL , P < .01 ; control children : cys-LTs , 4.3 pg/mL , 8-isoprostane , 3.5 pg/mL ) . Cys-LT levels were higher in children with unstable asthma than in the other two asthmatic groups ( P < .05 ) . FE(NO ) levels were significantly higher in steroid-naive and in children with unstable asthma compared with ICS-treated children with stable asthma ( P < .01 ) . CONCLUSIONS Our study shows that EBC cys-LTs and 8-isoprostane concentrations are higher in asthmatic children than in healthy control children , with scattered values in patients with unstable asthma . These findings suggest that EBC eicosanoid measurement may have useful clinical implication s for investigating phenotype differences among asthmatic patients Chronic airway inflammation in children with asthma might be present even in the absence of pathological lung function tests and is known to increase the risk of permanent pulmonary damage . Thus , we aim ed at investigating to what extent inflammatory markers such as leukotrienes ( LTs ) in exhaled breath condensate ( EBC ) or fractional exhaled nitric oxide ( FE(NO ) ) reflect therapeutic effects in these patients . Fifty steroid-naive patients ( aged 8.8 + /- 2.7 years ) were included in the study . EBC was collected before and 6 months after therapy with inhaled corticosteroids .  LTs were determined by using commercially available ELISA . In addition , FE(NO ) was measured by means of a chemiluminescence analyzer . Conventional lung function testing was performed revealing vital capacity , forced expiratory volume , maximum expiratory flow , and specific resistance . In EBC , LTE(4 ) but not LTB(4 ) levels significantly decreased after steroid therapy from 45.3 + /- 36.0 pg/mL to 17.2 + /- 11.4 pg/mL ( p < 0.0001 ) concomitant with a slight , but significant improvement of lung function parameters . Mean FE(NO ) also indicated therapeutic success ; however , in 20 of 50 patients , exhaled NO concentrations were higher after therapy . These findings suggest that LTE(4 ) in breath condensate may be helpful in latent inflammatory activity in the bronchial mucosa in children with asthma RATIONALE  Exhaled breath condensate pH ( EBC-pH )  may be useful noninvasive marker for evaluation of patients with asthma . OBJECTIVES To investigate the relationship between EBC-pH and symptoms suggestive of childhood asthma in an epidemiologic setting and examine its relation to lung function , airway hyperresponsiveness ( AHR ) , and airway inflammation . METHODS Within the context of a prospect i ve population -based birth cohort , EBC was collected from 630 children at age 8 yr using the  RTube ( pH measured after deaeration with argon ) . Lung function was measured by spirometry ( FEV1 ; n = 521 ) and plethysmography ( sRaw ; n = 567 ) , and AHR by methacholine challenge ( n = 498 ) . Airway inflammation was assessed using exhaled nitric oxide ( eNO ; n = 305 ) . RESULTS EBC-pH values ranged widely ( 4.40 - 8.29 ) , and did not differ between 54 children with parentally reported asthma and 562 nonasthmatic subjects ( median [ interquartile range ] : 7.75 [ 7.45 - 7.85 ] vs. 7.77 [ 7.59 - 7.87 ] ; p = 0.35 ) . There was a trend for lower EBC-pH among current wheezers ( n = 98 ; 7.72 [ 7.50 - 7.83 ] ) compared with nonwheezers ( n = 532 ; 7.77 [ 7.60 - 7.87 ] ; p = 0.07 ) . Wheeze frequency , severity , and use of antiasthma medication were not associated with EBC-pH. There was no consistent association between EBC-pH and lung function , airway reactivity , and airway inflammation ( FEV1 , sRaw , PD20 methacholine , or eNO ) . There was no significant difference in EBC-pH between current wheezers receiving asthma medication who had positive methacholine challenge compared with children without any of these features . CONCLUSIONS In the epidemiologic setting , EBC-pH does not differ between children with and without parentally reported symptoms suggestive of asthma . We found no consistent association between EBC-pH and lung function , AHR , and airway inflammation in this sample from the general population 
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