Local recurrence model of malignant pleural mesothelioma for investigation of intrapleural treatment

Objective: Local recurrence remains a major problem in the treatment of malignant pleural mesothelioma. The aim of the underlying study was to establish a standardised local recurrence model in rats which enables to study different intrapleural therapies. Materials and methods: Fifty microlitre containing 1×106 cells of a syngeneic rat malignant mesothelioma cell line (II-45), established from mesothelioma in Fischer 344 rats exposed to asbestos, were inoculated subpleurally via a left-sided thoracotomy. Tumour size was assessed 6 days later and the tumour nodule completely resected. Evaluation of recurrence at the resection site was performed after 10 days (n=6) and 6 days (n=6). The recurrent nodule was histopathologically confirmed. In a second experiment, this new recurrence model was evaluated for the effect of intrapleural therapy with different agents: 4ml of cisplatin-solution (100mg2/kg BW), cisplatin combined with the fibrin-based sealant Vivostat®, 4ml taurolidine 2%, repeated injection of 1μg of the chemokine CCL-19 at the tumour site and 4ml povidone-iodine in a dilution 1:10. In a control group, the chest cavity was filled with 4ml 0.9% NaCl. The primary endpoint was the extent of tumour recurrence. Results: Six days after inoculation, all animals presented a standardised tumour nodule at the injection site of a mean diameter of 5.1 (±0.8)mm. Evaluation of the recurrence after 10 days showed a relapse directly at the resection site, but additional tumour nodules on the ipsi- and contralateral chest wall were found and histologically confirmed. The animals that were sacrificed 6 days after resection of the tumour nodule showed a recurrence only at the resection site with no macroscopic or microscopic evidence of other tumour. Resection of the tumour nodule combined with intrapleural application of the different agents lead to clear reduction of recurrence. The strongest effect was observed after intrapleural application of cisplatin-Vivostat® with significant decrease of the longest, widest and thickest diameter of the recurrence. Conclusions: With this new recurrence model for investigation of malignant pleural mesothelioma in rats, we were able to investigate new intrapleural therapies after pneumonectomy. The intrapleural application of cisplatin-Vivostat® significantly reduced the extent of local recurrenc

Antimony and bismuth oxide cluster ions

The formation of charged antimony and bismuth oxide clusters in a pulsed arc cluster ion source (PACIS) has been studied with time-of-Ñight mass spectrometric techniques. We compare series of antimony and bismuth oxide cluster anions with their known cationic counterparts. The anionic series and (M 2 O 3 ) n MO 2h ave been predicted proceeding from the known cationic series and n Ob y adding O2~and have been experimentally established. All these series contain the metal atoms (M \ Sb or Bi) in the formal oxidation state ]3. However, only in the case of antimony, oxygen rich oxide clusters appear, that can be explained with a gradual transition in the oxidation number from ]3 to ]5 of single antimony atoms in the cluster. To estimate the inÑuence of the special oxide formation conditions comparative investigations with the PACIS and a laser vaporisation cluster source have been carried out for bismuth oxide cations. The similar oxide cluster distributions at comparable oxygen availability display clearly that the special thermodynamical stability of the discussed magic clusters is the signiÐcant driving force for their formation

Detailed spectral and morphological analysis of the shell type SNR RCW 86

Aims: We aim for an understanding of the morphological and spectral properties of the supernova remnant RCW~86 and for insights into the production mechanism leading to the RCW~86 very high-energy gamma-ray emission. Methods: We analyzed High Energy Spectroscopic System data that had increased sensitivity compared to the observations presented in the RCW~86 H.E.S.S. discovery publication. Studies of the morphological correlation between the 0.5-1~keV X-ray band, the 2-5~keV X-ray band, radio, and gamma-ray emissions have been performed as well as broadband modeling of the spectral energy distribution with two different emission models. Results:We present the first conclusive evidence that the TeV gamma-ray emission region is shell-like based on our morphological studies. The comparison with 2-5~keV X-ray data reveals a correlation with the 0.4-50~TeV gamma-ray emission.The spectrum of RCW~86 is best described by a power law with an exponential cutoff at $E_{cut}=(3.5\pm 1.2_{stat})$ TeV and a spectral index of $\Gamma$~$1.6\pm 0.2$. A static leptonic one-zone model adequately describes the measured spectral energy distribution of RCW~86, with the resultant total kinetic energy of the electrons above 1 GeV being equivalent to $\sim$0.1\% of the initial kinetic energy of a Type I a supernova explosion. When using a hadronic model, a magnetic field of $B$~100$\mu$G is needed to represent the measured data. Although this is comparable to formerly published estimates, a standard E$^{-2}$ spectrum for the proton distribution cannot describe the gamma-ray data. Instead, a spectral index of $\Gamma_p$~1.7 would be required, which implies that ~$7\times 10^{49}/n_{cm^{-3}}$erg has been transferred into high-energy protons with the effective density $n_{cm^{-3}}=n/ 1$ cm^-3. This is about 10\% of the kinetic energy of a typical Type Ia supernova under the assumption of a density of 1~cm^-3.Comment: accepted for publication by A&

The exceptionally powerful TeV gamma-ray emitters in the Large Magellanic Cloud

The Large Magellanic Cloud, a satellite galaxy of the Milky Way, has been observed with the High Energy Stereoscopic System (H.E.S.S.) above an energy of 100 billion electron volts for a deep exposure of 210 hours. Three sources of different types were detected: the pulsar wind nebula of the most energetic pulsar known N 157B, the radio-loud supernova remnant N 132D and the largest non-thermal X-ray shell - the superbubble 30 Dor C. The unique object SN 1987A is, surprisingly, not detected, which constrains the theoretical framework of particle acceleration in very young supernova remnants. These detections reveal the most energetic tip of a gamma-ray source population in an external galaxy, and provide via 30 Dor C the unambiguous detection of gamma-ray emission from a superbubble.Comment: Published in Science Magazine (Jan. 23, 2015). This ArXiv version has the supplementary online material incorporated as an appendix to the main pape

Variation of Basal EROD Activities in Ten Passerine Bird Species – Relationships with Diet and Migration Status

Inter-specific differences in animal defence mechanisms against toxic substances are currently poorly understood. The ethoxyresorufin-O-deethylase (EROD) enzyme plays an important role in defence against toxic chemicals in a wide variety of animals, and it is an important biomarker for environmental contamination. We compared basal hepatic EROD activity levels among ten passerine species to see if there is inter-specific variation in enzyme activity, especially in relation to their diet and migration status. Migratory insectivores showed higher EROD activity compared to granivores. We hypothesize that the variable invertebrate diet of migratory insectivores contains a wider range of natural toxins than the narrower diet of granivores. This may have affected the evolution of mixed function oxidases (MFO) system and enzyme activities. We further tested whether metabolic rates or relative liver size were associated with the variation in detoxification capacity. We found no association between EROD activity and relative (per mass unit) basal metabolic rate (BMR). Instead, EROD activity and relative liver mass (% of body mass) correlated positively, suggesting that a proportionally large liver also functions efficiently. Our results suggest that granivores and non-migratory birds may be more vulnerable to environmental contaminants than insectivores and migratory birds. The diet and migration status, however, are phylogenetically strongly connected to each other, and their roles cannot be fully separated in our analysis with only ten passerine species

The Chemical Evolution of the La0.6Sr0.4CoO3−δ Surface Under SOFC Operating Conditions and Its Implications for Electrochemical Oxygen Exchange Activity

© The Author(s) 2018Owing to its extraordinary high activity for catalysing the oxygen exchange reaction, strontium doped LaCoO3 (LSC) is one of the most promising materials for solid oxide fuel cell (SOFC) cathodes. However, under SOFC operating conditions this material suffers from performance degradation. This loss of electrochemical activity has been extensively studied in the past and an accumulation of strontium at the LSC surface has been shown to be responsible for most of the degradation effects. The present study sheds further light onto LSC surface changes also occurring under SOFC operating conditions. In-situ near ambient pressure X-ray photoelectron spectroscopy measurements were conducted at temperatures between 400 and 790 °C. Simultaneously, electrochemical impedance measurements were performed to characterise the catalytic activity of the LSC electrode surface for O2 reduction. This combination allowed a correlation of the loss in electro-catalytic activity with the appearance of an additional La-containing Sr-oxide species at the LSC surface. This additional Sr-oxide species preferentially covers electrochemically active Co sites at the surface, and thus very effectively decreases the oxygen exchange performance of LSC. Formation of precipitates, in contrast, was found to play a less important role for the electrochemical degradation of LSC.Fonds zur Förderung der wissenschaftlichen Forschung (FWF)212921411