The impact of different sampling techniques on the results of breath analysis was to be assessed in this study. Alveolar, mixed expiratory and time-controlled samples were collected from ten volunteers and from eight lung cancer patients. Breath sampling was visually controlled by means of capnometry. PCO(2) and 13 VOCs were determined. Mixed expiratory sampling yielded 25% lower concentrations of CO(2) and blood-borne VOCs. Time-controlled sampling generated high variation of results. Ratios C(alv)/C(mixed) were >1.5 for CO(2), acetone and isoprene, and <1 for isopropanol, 2-butanone and hexanal. Acetonitrile, butane, dimethylsulfide, pentane, butanal, benzene and hexane showed 1.5 > C(alv)/C(mixed) > 1. The ratio C(alv)/C(mixed) of CO(2), acetone and isoprene was different in healthy volunteers and lung cancer patients. Alveolar samples showed the highest concentrations of endogenous and lowest concentration of exogenous substances. Sampling can impact results in breath analysis. Valuable information can be obtained from ratios of alveolar and mixed expired concentrations.

In multiple myeloma, the overexpression of receptor activator of nuclear factor kappa B (NF-jB) ligand (RANKL) leads to the induction of NF-jB and activator protein-1 (AP-1)-related osteoclast activation and enhanced bone resorption. The purpose of this study was to examine the molecular and functional effects of proteasome inhibition in RANKL-induced osteoclastogenesis. Furthermore, we aimed to compare the outcome of proteasome versus selective NF-jB inhibition using bortezomib (PS-341) and I-jB kinase inhibitor PS-1145. Primary human osteoclasts were derived from CD14 þ precursors in presence of RANKL and macrophage colony-stimulating factor (M-CSF). Both bortezomib and PS-1145 inhibited osteoclast differentiation in a dose-and time-dependent manner and furthermore, the bone resorption activity of osteoclasts. The mechanisms of action involved in early osteoclast differentiation were found to be related to the inhibition of p38 mitogenactivated protein kinase pathways, whereas the later phase of differentiation and activation occurred due to inhibition of p38, AP-1 and NF-jB activation. The AP-1 blockade contributed to significant reduction of osteoclastic vascular endothelial growth factor production. In conclusion, our data demonstrate that proteasomal inhibition should be considered as a novel therapeutic option of cancer-induced lytic bone disease.

These data on the metformin-trimethoprim interaction support the potential utility of N(1)-methylnicotinamide as an endogenous probe for renal drug-drug interactions with involvement of renal cation transporters.

Using a large series of myeloma patients, we could show for the first time a correlation between DKK-1 serum concentration and the amount of lytic bone disease, indicating that DKK-1 is an important factor for the extent of bone disease and supporting the hypothesis of DKK-1 as a therapeutic target in myeloma bone disease.