Validation of 8-isoprostane and prostaglandin E(2) measurements in exhaled breath condensate.
OBJECTIVE
To qualitatively validate radioimmunoassays for 8-isoprostane and prostaglandin (PG) E(2) in exhaled breath condensate.


METHODS
Twenty-two subjects with different lung diseases attended the outpatient clinic on one occasion for exhaled breath condensate collection.


METHODS
Samples were pooled together and purified by reverse phase high performance liquid chromatography (RP-HPLC). The eluted fractions were assayed for 8-isoprostane-like immunoreactivity and PGE(2)-like immunoreactivity by radioimmunoassays. In addition, simultaneous measurements of exhaled breath condensate unextracted samples with two anti-8-isoprostane and anti-PGE(2) sera with different cross-reactivity were performed.


RESULTS
A single peak of 8-isoprostane-like immunoreactivity and PGE(2)-like immunoreactivity co-eluting with 8-isoprostane (retention time: 13 min) and PGE(2) (retention time: 21 min) standards, respectively, was identified by radioimmunoassays. Testing with two different antisera showed similar results for both 8-isoprostane-like immunoreactivity (limits of agreement = 4.5 pg/ml and - 4.1 pg/ml, n = 12) and PGE(2)-like immunoreactivity (limits of agreement = 6.1 pg/ ml and - 6.1 pg/ml, n = 12).


CONCLUSIONS
This study provides evidence for the specificity of the radioimmunoassays for 8-isoprostane and PGE(2) in exhaled breath condensate. This is critical for proposing these markers as a non-invasive way for monitoring airway inflammation.
Department of Pharmacology, School of Medicine, Catholic University of the Sacred Heart, L go F Vito, 00168, Rome, Italy. pmontuschi@rm.unicatt.it
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Montuschi
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Ragazzoni
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Valente
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Corbo
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Mondino
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Ciappi
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Ciabattoni
D001944:Breath Tests / Q000379:methods*; D002851:Chromatography, High Pressure Liquid; D015232:Dinoprostone / Q000032:analysis* / Q000097:blood; D005260:Female; D006801:Humans; D028421:Isoprostanes / Q000032:analysis* / Q000097:blood; D008171:Lung Diseases / Q000097:blood / Q000175:diagnosis* / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D011863:Radioimmunoassay; D015203:Reproducibility of Results; D012119:Respiration
D028421:Isoprostanes; D015232:Dinoprostone