PreSens GmbH

Regensburg, Germany

PreSens GmbH

Regensburg, Germany
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Jennewein J.,Klinikum Nurnberg Sud | Jennewein J.,Friedrich - Alexander - University, Erlangen - Nuremberg | Jennewein J.,University of Regensburg | Matuszak J.,Klinikum Nurnberg Sud | And 13 more authors.
Cellular Microbiology | Year: 2015

In Salmonella infection, the Salmonella pathogenicity island-2 (SPI-2)-encoded type three secretion system (T3SS2) is of key importance for systemic disease and survival in host cells. For instance, in the streptomycin-pretreated mouse model SPI-2-dependent Salmonella replication in lamina propria CD11c-CXCR1- monocytic phagocytes/macrophages (MΦ) is required for the development of colitis. In addition, containment of intracellular Salmonella in the gut critically depends on the antimicrobial effects of the phagocyte NADPH oxidase (PHOX), and possibly type 2 nitric oxide synthase (NOS2). For both antimicrobial enzyme complexes, oxygen is an essential substrate. However, the amount of available oxygen upon enteroinvasive Salmonella infection in the gut tissue and its impact on Salmonella-MΦ interactions was unknown. Therefore, we measured the gut tissue oxygen levels in a model of Salmonella enterocolitis using luminescence two-dimensional in vivo oxygen imaging. We found that gut tissue oxygen levels dropped from ~78 Torr (~11% O2) to values of ~16 Torr (~2% O2) during infection. Because in vivo virulence of Salmonella depends on the Salmonella survival in MΦ, Salmonella-MΦ interaction was analysed under such low oxygen values. These experiments revealed an increased intracellular replication and survival of wild-type and t3ss2 non-expressing Salmonella. These findings were paralleled by blunted nitric oxide and reactive oxygen species (ROS) production and reduced SalmonellaROS perception. In addition, hypoxia enhanced SPI-2 transcription and translocation of SPI-2-encoded virulence protein. Neither pharmacological blockade of PHOX and NOS2 nor impairment of T3SS2 virulence function alone mimicked the effect of hypoxia on Salmonella replication under normoxic conditions. However, if t3ss2 non-expressing Salmonella were used, hypoxia did not further enhance Salmonella recovery in a PHOX and NOS2-deficient situation. Hence, these data suggest that hypoxia-induced impairment of antimicrobial activity and Salmonella virulence cooperate to allow for enhanced Salmonella replication in MΦ. © 2015 John Wiley & Sons Ltd.


PubMed | Presens GmbH, ETH Zurich, University of Osnabrück, Robert Koch Institute and 2 more.
Type: Journal Article | Journal: Cellular microbiology | Year: 2015

In Salmonella infection, the Salmonella pathogenicity island-2 (SPI-2)-encoded type three secretion system (T3SS2) is of key importance for systemic disease and survival in host cells. For instance, in the streptomycin-pretreated mouse model SPI-2-dependent Salmonella replication in lamina propria CD11c(-)CXCR1(-) monocytic phagocytes/macrophages (M) is required for the development of colitis. In addition, containment of intracellular Salmonella in the gut critically depends on the antimicrobial effects of the phagocyte NADPH oxidase (PHOX), and possibly type 2 nitric oxide synthase (NOS2). For both antimicrobial enzyme complexes, oxygen is an essential substrate. However, the amount of available oxygen upon enteroinvasive Salmonella infection in the gut tissue and its impact on Salmonella-M interactions was unknown. Therefore, we measured the gut tissue oxygen levels in a model of Salmonella enterocolitis using luminescence two-dimensional in vivo oxygen imaging. We found that gut tissue oxygen levels dropped from 78 Torr (11% O2) to values of 16 Torr (2% O2) during infection. Because in vivo virulence of Salmonella depends on the Salmonella survival in M, Salmonella-M interaction was analysed under such low oxygen values. These experiments revealed an increased intracellular replication and survival of wild-type and t3ss2 non-expressing Salmonella. These findings were paralleled by blunted nitric oxide and reactive oxygen species (ROS) production and reduced SalmonellaROS perception. In addition, hypoxia enhanced SPI-2 transcription and translocation of SPI-2-encoded virulence protein. Neither pharmacological blockade of PHOX and NOS2 nor impairment of T3SS2 virulence function alone mimicked the effect of hypoxia on Salmonella replication under normoxic conditions. However, if t3ss2 non-expressing Salmonella were used, hypoxia did not further enhance Salmonella recovery in a PHOX and NOS2-deficient situation. Hence, these data suggest that hypoxia-induced impairment of antimicrobial activity and Salmonella virulence cooperate to allow for enhanced Salmonella replication in M.


Atamanchuk D.,Gothenburg University | Tengberg A.,Gothenburg University | Tengberg A.,Aanderaa Data Instruments AS | Thomas P.J.,Christian Michelsen Research | And 4 more authors.
Limnology and Oceanography: Methods | Year: 2014

This article reports the performance of an improved, newly developed, compact, low power, lifetime-based optical sensor (optode) for measuring partial pressure of dissolved CO2 gas (pCO2) in natural waters. The results suggest that after preconditioning, these sensors are stable in water for time periods longer than 7 months. The wide dynamic range of about 0-50000 μatm opens possibilities for numerous applications of which some are presented. In normal marine environments with pCO2 levels of 200-1000 μatm, the best-obtained precision was about ±2 μatm, and the absolute accuracy was between 2-75 μatm, depending on the deployment and the quality of the collected reference water samples. One limitation is that these sensors will become irreversibly poisoned by H2S and should thus not be deployed in sulphidic environments. © 2014, by the American Society of Limnology and Oceanography, Inc.


Thomas P.J.,Christian Michelsen Research | Pedersen G.,Christian Michelsen Research | Hide A.,MMC Tendos AS | Apostolidis A.,PreSens GmbH | And 7 more authors.
OCEANS 2013 MTS/IEEE Bergen: The Challenges of the Northern Dimension | Year: 2013

This paper describes our progress towards the development of field deployable pCO2 and NH3 in water measurement technologies. The fluorescence lifetime based pCO2 technology described here has a wide dynamic range of 102-5×104 microatmospheres and has undergone numerous field trials that indicate suitability to a wide range of short and long term monitoring applications. The spectrophotometric NH 3 technology described is in an earlier stage of development, and the characterization experiments performed to date show that the technology responds reversibly to ammonia concentrations at the low ppb level and could therefore be applicable to a wide range of applications within aquaculture and oceanography. The pCO2 and NH3 sensor prototypes used in these investigations are based on the same mechanical platform, that in future could also form the basis for other water quality monitoring technologies. © 2013 IEEE.


Hofmann J.,Friedrich - Alexander - University, Erlangen - Nuremberg | Meier R.J.,University of Regensburg | Mahnke A.,Friedrich - Alexander - University, Erlangen - Nuremberg | Schatz V.,Friedrich - Alexander - University, Erlangen - Nuremberg | And 7 more authors.
Methods and Applications in Fluorescence | Year: 2013

Tissue oxygenation plays a critical role in the pathogenesis of various diseases, but non-invasive, robust and user-friendly methods for its measurement in vivo still need to be established. Here, we are presenting an in vivo oxygen-detection system that uses ratiometric luminescence imaging (RLI) as a readout scheme to determine the skin oxygen tension of mouse hind footpads via side-by-side comparison with more established techniques including luminescence-lifetime imaging using planar sensor films and the polarographic electrode as the gold standard. We also demonstrate that this technology allows the detection of changes in mouse skin tissue oxygenation induced by subjecting mice to systemic hypoxia. The data demonstrate oxygen imaging based on RLI to be a most useful tool for reliably and easily analyzing and monitoring skin tissue oxygenation in vivo. This technology will advance our understanding of local regulation of skin tissue oxygenation in various disease conditions. © 2013 IOP Publishing Ltd.


Meier J.K.,University of Regensburg | Prantl L.,University of Regensburg | Geis S.,University of Regensburg | Mueller S.,University of Regensburg | And 3 more authors.
Clinical Hemorheology and Microcirculation | Year: 2013

BACKGROUND: In a preliminary trial, we were able to show first promising results in the analysis of perioperative and postoperative perfusion of free flaps by means of a new monitoring system for detecting thrombotic vessel occlusion before clinical signs become evident. OBJECTIVE: We investigated whether flap monitoring by measuring perfusion-dependent parameters differs between radial forearm and fibular free flaps and whether a threshold value requiring anastomosis revision could be determined. METHODS: 37 radial forearm flaps (RF) and 15 fibular flaps (FF) were harvested and transplanted. Perfusion was determined by measuring a fluorescent oxygen sensor foil covering a flap's skin surface with a handheld fluorescence microscope. The sensor contained an oxygen reservoir, which was consumed by the tissue corresponding to the perfusion status of the flap. Measurements were done before explantation, after successful anastomosis and one day after surgery. RESULTS: We found a significant difference (p < 0.005) in the relative transdermal oxygen consumption (RTOC) between clinically well-perfused grafts (RF: mean: 0.13 ± 0.08; FF: mean: 0.15 ± 0.07) and clinically poorly perfused grafts (RF: mean: 0.40 ± 0.09; FF: mean: 0.55 ± 0.28). A threshold RTOC value of 0.3 for differentiating between well-perfused and poorly perfused flaps was confirmed for both RF and FF. © 2013 - IOS Press and the authors. All rights reserved.


Meier J.K.,University Medical CentreRegensburg | Prantl L.,University of Regensburg | Geis S.,University of Regensburg | Mueller S.,University Medical CentreRegensburg | And 3 more authors.
Clinical Hemorheology and Microcirculation | Year: 2014

A threshold RTOC value of 0.3 for differentiating between well-perfused and poorly perfused flaps was confirmed for both RF and FF. © 2014 - IOS Press and the authors. All rights reserved.Background: In a preliminary trial, we were able to show first promising results in the analysis of perioperative and postoperative perfusion of free flaps by means of a new monitoring system for detecting thrombotic vessel occlusion before clinical signs become evident.Objective: We investigated whether flap monitoring by measuring perfusion-dependent parameters differs between radial forearm and fibular free flaps and whether a threshold value requiring anastomosis revision could be determined.Methods: 37 radial forearm flaps (RF) and 15 fibular flaps (FF) were harvested and transplanted. Perfusion was determined by measuring a fluorescent oxygen sensor foil covering a flap's skin surface with a handheld fluorescence microscope. The sensor contained an oxygen reservoir, which was consumed by the tissue corresponding to the perfusion status of the flap. Measurements were done before explantation, after successful anastomosis and one day after surgery.Results: We found a significant difference (p < 0.005) in the relative transdermal oxygen consumption (RTOC) between clinically well-perfused grafts (RF: mean: 0.13 ± 0.08; FF: mean: 0.15 ± 0.07) and clinically poorly perfused grafts (RF: mean: 0.40 ± 0.09; FF: mean: 0.55 ± 0.28).

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