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Eosinophilic inflammation in chronic obstructive pulmonary disease (COPD) is predictive for responses to inhaled steroids. We hypothesised that the inflammatory subtype in mild and moderate COPD can be assessed by exhaled breath metabolomics.Exhaled compounds were analysed using gas chromatography and mass spectrometry (GC-MS) and electronic nose (eNose) in 28 COPD patients (12/16 Global Initiative for Chronic Obstructive Lung Disease (GOLD) stage I/II, respectively). Differential cell counts, eosinophil cationic protein (ECP) and myeloperoxidase (MPO) were measured in induced sputum. Relationships between exhaled compounds, eNose breathprints and sputum inflammatory markers were analysed and receiver operating characteristic (ROC) curves were constructed.Exhaled compounds were highly associated with sputum cell counts (eight compounds with eosinophils, 17 with neutrophils; p,0.01). Only one compound (alkylated benzene) overlapped between eosinophilic and neutrophilic profiles. GC-MS and eNose breathprints were associated with markers of inflammatory activity in GOLD stage I (ECP: 19 compounds, p,0.01; eNose breathprint r50.84, p50.002) (MPO: four compounds, p,0.01; eNose r50.72, p50.008). ROC analysis for eNose showed high sensitivity and specificity for inflammatory activity in mild COPD (ECP: area under the curve (AUC) 1.00; MPO: AUC 0.96) but not for moderate COPD.Exhaled molecular profiles are closely associated with the type of inflammatory cell and their activation status in mild and moderate COPD. This suggests that breath analysis may be used for assessment and monitoring of airway inflammation in COPD.

MRI contrast agents based on chemical exchange-dependent saturation transfer (CEST), such as Yb(III)DOTAM complexes, are highly suitable for pH mapping. In this paper, the synthesis of Yb(III)DOTAM-functionalized poly(propylene imine) dendrimers is described. The applicability of these dendritic PARACEST MRI agents for pH mapping has been evaluated on a 7 T NMR spectrometer and on a 3 T clinical MRI scanner. As expected, based on the different numbers of exchangeable amide protons, the lowest detectable concentration of the first and third generation dendritic PARACEST agents is by a respective factor of about 4 and 16 lower than that of a mononuclear reference complex. The pH dependence of the CEST effect observed for these compounds depends on the generation of the poly(propylene imine) dendrimer. Upon going to higher generations of the Yb(III)DOTAM-terminated dendrimer, a shift of the maximum CEST effect towards lower pH values was observed. This allows for a fine-tuning of the responsive pH region by varying the dendritic framework.

Assessment of the surface tension of low-energy solids by means of easy to perform contact angle measurements would be very attractive. Two different approaches are frequently reported to be very promising in this respect. We have evaluated these approaches using mainly apolar surfaces, which present the simplest case possible. The "equation of state" approach, which uses a single parameter, correctly predicts the results on FC722 (perfluoropolyacrylate) and FEP (poly(tetrafluoroethylene-cohexafluoropropylene)), but shows systematic deviations on the surfaces of octyltrichlorosilane (self-assembled on glass) and PE (polyethylene). The "surface tension components" approach uses three parameters. The surface tension is split into a van der Waals component, a Lewis acid component, and a Lewis base component. The determination of the surface tension of apolar surfaces yields reasonably consistent results when using a large set of contact angle data. However, the present results indicate important differences with previously reported values of the van der Waals components of some fluids, i.e., dimethyl sulfoxide (DMSO), formamide, diiodomethane, and 1-bromonaphthalene. The latter two appear not to be apolar in nature when obtained from measurements on FC722 or FEP. The difference with previous reports is due to a discrepancy between the contact angles of diiodomethane and 1-bromonaphthalene measured on either FC722 or PE. It is concluded that neither the "equation of state" nor the "surface tension components" approach can account for all experimental results. The present use of contact angle measurements appears to be limited to the estimation of the surface tension of apolar surfaces, using the "surface tension components" approach.