Toll-like receptor (TLR)10 is the only pattern-recognition receptor without known ligand specificity and biological function. We demonstrate that TLR10 is a modulatory receptor with mainly inhibitory effects. Blocking TLR10 by antagonistic antibodies enhanced proinflammatory cytokine production, including IL-1β, specifically after exposure to TLR2 ligands. Blocking TLR10 after stimulation of peripheral blood mononuclear cells with pam3CSK4 (Pam3Cys) led to production of 2,065 ± 106 pg/mL IL-1β (mean ± SEM) in comparison with 1,043 ± 51 pg/mL IL-1β after addition of nonspecific IgG antibodies. Several mechanisms mediate the modulatory effects of TLR10: on the one hand, cotransfection in human cell lines showed that TLR10 acts as an inhibitory receptor when forming heterodimers with TLR2; on the other hand, cross-linking experiments showed specific induction of the anti-inflammatory cytokine IL-1 receptor antagonist (IL-1Ra, 16 ± 1.7 ng/mL, mean ± SEM). After cross-linking anti-TLR10 antibody, no production of IL-1β and other proinflammatory cytokines could be found. Furthermore, individuals bearing TLR10 polymorphisms displayed an increased capacity to produce IL-1β, TNF-α, and IL-6 upon ligation of TLR2, in a gene-dose-dependent manner. The modulatory effects of TLR10 are complex, involving at least several mechanisms: there is competition for ligands or for the formation of heterodimer receptors with TLR2, as well as PI3K/Aktmediated induction of the anti-inflammatory cytokine IL-1Ra. Finally, transgenic mice expressing human TLR10 produced fewer cytokines when challenged with a TLR2 agonist. In conclusion, to our knowledge we demonstrate for the first time that TLR10 is a modulatory pattern-recognition receptor with mainly inhibitory properties.ighly conserved molecular structures of invading microorganisms are recognized by immune cells through patternrecognition receptors, of which Toll-like receptors (TLRs) are the most documented family. In humans, 10 members of the TLR family have been described (1). In general, specific ligation of TLRs leads to induction of proinflammatory mediators, such as cytokines and chemokines. One member of the TLR family however, TLR10, is considered an orphan receptor because of its still-unknown ligands and function.Human TLR10 is encoded on chromosome 4 within the TLR2 gene cluster, together with TLR1, TLR2, and TLR6, and shares all structural characteristics of the TLR family (2, 3). However, TLR10 differs from other TLRs by its lack of a classic downstream signaling pathway (4), despite its interaction with the myeloid differentiation primary response gene 88 adaptor protein (3). TLR10 is predominantly expressed in tissues rich in immune cells, such as spleen, lymph node, thymus, tonsil, and lung (2). Expression of TLR10 can be induced in B cells, dendritic cells, eosinophils, and neutrophils (3, 5, 6), as well as on nonimmune cells, such as trophoblasts (7). TLR1 and TLR6 are known to form heterodimers with TLR2, and this was shown for TLR10 as well (3,8). It is therefore ...

Abstract. Variations of stable water isotopes in water vapourhave become measurable at a measurement frequency of about 1 Hz in recent years using novel laser spectroscopic techniques. This enables us to perform continuous measurements for process-based investigations of the atmospheric water cycle at the time scales relevant for synoptic and mesoscale meteorology. An important prerequisite for the interpretation of data from automated field measurements lasting for several weeks or months is a detailed knowledge about instrument properties and the sources of measurement uncertainty. We present here a comprehensive characterisation and comparison study of two commercial laser spectroscopic systems based on cavity ring-down spectroscopy (Picarro) and off-axis integrated cavity output spectroscopy (Los Gatos Research). The uncertainty components of the measurements were first assessed in laboratory experiments, focussing on the effects of (i) water vapour mixing ratio, (ii) measurement stability, (iii) uncertainties due to calibration and (iv) response times of the isotope measurements due to adsorption-desorption processes on the tubing and measurement cavity walls. Based on the experience from our laboratory experiments, we set up a one-week field campaign for comparing measurements of the ambient isotope signals from the two laser spectroscopic systems. The optimal calibration strategy determined for both instruments was applied as well as the correction functions for water vapour mixing ratio effects. The root mean square difference between the isotope signals from the two instruments during the field deployment was 2.3 ‰ for δ 2 H, 0.5 ‰ for δ 18 O and 3.1 ‰ for deuterium excess. These uncertainty estimates from field measurements compare well to those found in the laboratory experiments. The present quality of measurements from laser spectroscopic instruments combined with a calibration system opens new possibilities for investigating the atmospheric water cycle and the land-atmosphere moisture fluxes.

Abstract. We present a detailed assessment of a commercially available water vapor isotope analyzer (WVIA, Los Gatos Research, Inc.) for simultaneous in-situ measurements of δ 2 H and δ 18 O in water vapor. This method, based on offaxis integrated cavity output spectroscopy, is an alternative to the conventional water trap/isotope ratio mass spectrometry (IRMS) techniques. We evaluate the analyzer in terms of precision, memory effects, concentration dependence, temperature sensitivity and long-term stability. A calibration system based on a droplet generator is used to characterize the performance and to calibrate the analyzer. Our results show that the precision at an averaging time of 15 s is 0.16‰ for δ 2 H and 0.08‰ for δ 18 O. The isotope ratios are strongly dependent on the water mixing ratio of the air. Taking into account this concentration dependence as well as the temperature sensitivity of the instrument we obtained a long-term stability of the water isotope measurements of 0.38‰ for δ 2 H and 0.25‰ for δ 18 O. The accuracy of the WVIA was further assessed by comparative measurements using IRMS and a dew point generator indicating a linear response in isotopic composition and H 2 O concentrations. The WVIA combined with a calibration system provides accurate high resolution water vapor isotope measurements and opens new possibilities for hydrological and ecological applications.

The timely detection of metastatic infectious foci in gram-positive bacteremia is crucial, because these foci often require prolonged antibiotic treatment or drainage. The diagnosis of metastatic infectious foci is difficult because localizing symptoms are often absent. We investigated whether 18 F-FDG PET/CT was able to detect such foci and whether detection influenced clinical outcome. Methods: One hundred fifteen nonneutropenic patients with gram-positive bacteremia were prospectively included. Patients with positive blood cultures growing Staphylococcus aureus, Streptococcus species, or Enterococcus species were eligible when a risk factor for developing metastatic infectious foci was present. 18 F-FDG PET/CT was performed within 2 wk after the first positive blood culture. Abnormal 18 F-FDG uptake had to be confirmed by radiologic, microbiologic, or pathologic studies. Results were compared with a matched historical control group of 230 patients in whom no 18 F-FDG PET/CT was performed. Results: Significantly more patients were diagnosed with metastatic foci in the study group (67.8% vs. 35.7%). Of the imaging investigations performed, 18 F-FDG PET/CT was the first to delineate infectious foci in 35 patients (30%). In the remaining 70%, either symptoms on physical examination or other imaging techniques first revealed infectious foci. The sensitivity, specificity, negative predictive value, and positive predictive value of 18 F-FDG PET/CT were 100%, 87%, 100%, and 89%, respectively. Relapse rates decreased from 7.4% to 2.6% among study patients (P 5 0.09) and from 8.9% to 1.4% in patients with S. aureus (P 5 0.04). Overall mortality after 6 mo decreased from 32.2% to 19.1% in the 18 F-FDG PET/CT group (P 5 0.014). Conclusion: In the diagnostic work-up of high-risk patients with gram-positive bacteremia, 18 F-FDG PET/CT is a valuable technique that results in lower mortality rates. In patients with S. aureus bacteremia, relapse rates decreased significantly after the addition of 18 F-FDG PET/CT.

SOD and SDD have marked effects on the bacterial ecology in an ICU, with rising ceftazidime resistance prevalence rates in the respiratory tract during intervention and a considerable rebound effect of ceftazidime resistance in the intestinal tract after discontinuation of SDD.

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Abstract. We present the continuous data record of atmospheric CO2 isotopes measured by laser absorption spectroscopy for an almost four year period at the High Altitude Research Station Jungfraujoch (3580 m a.s.l.), Switzerland. The mean annual cycles derived from data of December 2008 to September 2012 exhibit peak-to-peak amplitudes of 11.0 μmol mol−1 for CO2, 0.60‰ for δ13C and 0.81‰ for δ18O. The high temporal resolution of the measurements also allow us to capture variations on hourly and diurnal timescales. For CO2 the mean diurnal peak-to-peak amplitude is about 1 μmol mol−1 in spring, autumn and winter and about 2 μmol mol−1 in summer. The mean diurnal variability in the isotope ratios is largest during the summer months too, with an amplitude of about 0.1‰ both in the δ13C and δ18O, and a smaller or no discernible diurnal cycle during the other seasons. The day-to-day variability, however, is much larger and depends on the origin of the air masses arriving at Jungfraujoch. Backward Lagrangian particle dispersion model simulations revealed a close link between air composition and prevailing transport regimes and could be used to explain part of the observed variability in terms of transport history and influence region. A footprint clustering showed significantly different wintertime CO2, δ13C and δ18O values depending on the origin and surface residence times of the air masses. Several major updates on the instrument and the calibration procedures were performed in order to further improve the data quality. We describe the new measurement and calibration setup in detail and demonstrate the enhanced performance of the analyzer. A measurement precision of about 0.02‰ for both isotope ratios has been obtained for an averaging time of 10 min, while the accuracy was estimated to be 0.1‰, including the uncertainty of the calibration gases.

Osteoclast-like giant cell tumors (OCGTs) of the pancreas and liver are enigmatic tumors. Despite their striking morphologic resemblance to certain mesenchymal tumors of bone and tendon sheath, it has been suggested that these tumors may, in fact, arise from epithelial precursors. It is also unclear whether the osteoclast-like giant cells in OCGTs are neoplastic or nonneoplastic. We identified OCGTs of the pancreas and liver that were associated with atypical intraductal epithelial proliferations or mucinous cystic neoplasms. To determine the relationship between the noninvasive epithelial proliferations and the infiltrating OCGTs, each individual component was analyzed for mutations at codon 12 of the K-ras oncogene. Four of the five-duct epithelial lesions harbored activating mutations of the K-ras oncogene. In each case, the same K-ras mutation was also present in the mononuclear cells from the paired OCGT. Moreover, these same mutations were detected when the osteoclast-like giant cells were individually microdissected and analyzed. A panel of immunohistochemical stains was performed, and the osteoclast-like giant cells demonstrated macrophage differentiation. These cells were consistently reactive for the monocyte/macrophage marker KP1, but showed absent staining for a panel of epithelial markers. The infiltrating mononuclear cells lacked strong staining for epithelial markers and monocyte/macrophage markers. These findings suggest that OCGTs of the pancreas and liver are undifferentiated carcinomas that arise directly from intraductal epithelial precursors. The finding of K-ras mutations in the osteoclast-like giant cells may reflect their propensity to phagocytize tumor cells.