Involvement of E. coli 6S RNA in Oxidative Stress Response.

6S RNA, a small non-coding RNA present in almost all bacteria, inhibits transcription via direct binding to RNA polymerase holoenzymes. The mechanism of 6S RNA action was investigated to a large extent in E. coli, however, lack of 6S RNA (ΔssrS) was demonstrated to be unfavorable but not essential for cell survival under various growth conditions. In the present study, we revealed, for the first time, a lethal phenotype of the ΔssrS strain in the presence of high concentrations of H2O2. This phenotype was rescued by complementation of the ssrS gene on a plasmid. We performed comparative qRT-PCR analyses on an enlarged set of mRNAs of genes associated with the oxidative stress response, allowing us to identify four genes known to be involved in this pathway (soxS, ahpC, sodA and tpx) that had decreased mRNA levels in the ΔssrS strain. Finally, we performed comparative proteomic analyses of the wild-type and ΔssrS strains, confirming that ΔssrS bacteria have reduced levels of the proteins AhpC and Tpx involved in H2O2 reduction. Our findings substantiate the crucial role of the riboregulator 6S RNA for bacterial coping with extreme stresses.

Northern Blot Detection of Tiny RNAs.

Successful detection of very small RNAs (tiny RNAs, ~8-15 nt in length) by northern blotting depends on tailored protocols with respect to transfer and immobilization on membranes as well as design of sensitive detection probes. For RNA crosslinking to positively charged membranes, we compared UV light with chemical RNA crosslinking by 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDC), using either denaturing or native polyacrylamide gels. We show that northern blot detection of tiny RNAs with 5'-digoxigenin-labeled DNA/LNA mixmer probes is a highly sensitive and specific method and, in our hands, more sensitive than using a corresponding DNA/LNA mixmer probe with a 5'-32P-end-label. Furthermore, we provide a robust protocol for northern blot analysis of noncoding RNAs of intermediate size (~50-400 nt).

6S-2 RNA deletion in the undomesticated B. subtilis strain NCIB 3610 causes a biofilm derepression phenotype.

Bacterial 6S RNA regulates transcription via binding to the active site of RNA polymerase holoenzymes. 6S RNA has been identified in the majority of bacteria, in most cases encoded by a single gene. Firmicutes including Bacillus subtilis encode two 6S RNA paralogs, 6S-1 and 6S-2 RNA. Hypothesizing that the regulatory role of 6S RNAs may be particularly important under natural, constantly changing environmental conditions, we constructed 6S RNA deletion mutants of the undomesticated B. subtilis wild-type strain NCIB 3610. We observed a strong phenotype for the ∆6S-2 RNA strain that showed increased biofilm formation on solid media and the ability to form surface-attached biofilms in liquid culture. This phenotype remained undetected in derived laboratory strains (168, PY79) that are defective in biofilm formation. Quantitative RT-PCR data revealed transcriptional upregulation of biofilm marker genes such as tasA, epsA and bslA in the ∆6S-2 RNA strain, particularly during transition from exponential to stationary growth phase. Salt stress, which blocks sporulation at a very early stage, was found to override the derepressed biofilm phenotype of the ∆6S-2 RNA strain. Furthermore, the ∆6S-2 RNA strain showed retarded swarming activity and earlier spore formation. Finally, the ∆6S-1&2 RNA double deletion strain showed a prolonged lag phase of growth under oxidative, high salt and alkaline stress conditions, suggesting that the interplay of both 6S RNAs in B. subtilis optimizes and fine-tunes transcriptomic adaptations, thereby contributing to the fitness of B. subtilis under the unsteady and temporarily harsh conditions encountered in natural habitats.

4D deep learning for real-time volumetric optical coherence elastography.

PURPOSE: Elasticity of soft tissue provides valuable information to physicians during treatment and diagnosis of diseases. A number of approaches have been proposed to estimate tissue stiffness from the shear wave velocity. Optical coherence elastography offers a particularly high spatial and temporal resolution. However, current approaches typically acquire data at different positions sequentially, making it slow and less practical for clinical application. METHODS: We propose a new approach for elastography estimations using a fast imaging device to acquire small image volumes at rates of 831 Hz. The resulting sequence of phase image volumes is fed into a 4D convolutional neural network which handles both spatial and temporal data processing. We evaluate the approach on a set of image data acquired for gelatin phantoms of known elasticity. RESULTS: Using the neural network, the gelatin concentration of unseen samples was predicted with a mean error of 0.65 ± 0.81 percentage points from 90 subsequent volumes of phase data only. We achieve a data acquisition and data processing time of under 12 ms and 22 ms, respectively. CONCLUSIONS: We demonstrate direct volumetric optical coherence elastography from phase image data. The approach does not rely on particular stimulation or sampling sequences and allows the estimation of elastic tissue properties of up to 40 Hz.

MCC950 blocks enhanced interleukin-1ß production in patients with NLRP3 low penetrance variants.

OBJECTIVE: To determine the role of the NLRP3 inflammasome by using the selective NLRP3 inhibitor MCC950 in patients with NLRP3 low penetrance variants and clinical symptoms suggestive for an autoinflammatory syndrome including central nervous system (CNS) involvement. METHODS: Nineteen symptomatic patients with low penetrance NLRP3 variants (Q703K n = 17, V198M n = 2) recruited between 2011 and 2017 were included in this monocentric study. A functional inflammasome activation assay was performed in patients in comparison to healthy controls (HC), including the determination of interleukin-1beta (IL-1ß), interleukin-6 (IL-6) and tumor-necrosis factor alpha (TNF-α) secretion in the presence of the NLRP3 selective small-molecule inhibitor MCC950. Detailed clinical features were assessed and anti-IL-1 treatment response was determined. RESULTS: Peripheral blood mononuclear cells (PBMC) from patients with low penetrance NLRP3 variants displayed enhanced IL-1ß levels following inflammasome activation compared to HC. Furthermore, IL-1ß release was NLRP3-dependent as it was blocked by MCC950. The production of IL-6 and TNF-α was also increased in patients with low penetrance NLRP3 variants. Clinically, they presented with a heterogenous spectrum of neurological manifestations, while cranial nerve inflammation was the most common feature. Overall inflammasome activation did not correlate with disease severity. Eight of ten treated patients responded to anti IL-1 treatment, however a complete response was only documented in four patients. CONCLUSION: PBMC of several patients with NLRP3 low penetrance variants and CNS manifestation showed increased NLRP3-specific IL-1ß release upon stimulation and elevated NLRP3-independent IL-6 and TNF-α levels as those were not suppressed by MCC950. Our data suggest that beside the possible causal involvement of the NLRP3 inflammasome additional, yet unidentified genetic or environmental factors may contribute to the multi-organ inflammation in our patients and explain the partial response to IL-1 targeting therapies.

Introducing the H2020 AQUACROSS project: Knowledge, Assessment, and Management for AQUAtic Biodiversity and Ecosystem Services aCROSS EU policies.

The AQUACROSS project was an unprecedented effort to unify policy concepts, knowledge, and management of freshwater, coastal, and marine ecosystems to support the cost-effective achievement of the targets set by the EU Biodiversity Strategy to 2020. AQUACROSS aimed to support EU efforts to enhance the resilience and stop the loss of biodiversity of aquatic ecosystems as well as to ensure the ongoing and future provision of aquatic ecosystem services. The project focused on advancing the knowledge base and application of Ecosystem-Based Management. Through elaboration of eight diverse case studies in freshwater and marine and estuarine aquatic ecosystem across Europe covering a range of environmental management problems including, eutrophication, sustainable fisheries as well as invasive alien species AQUACROSS demonstrated the application of a common framework to establish cost-effective measures and integrated Ecosystem-Based Management practices. AQUACROSS analysed the EU policy framework (i.e. goals, concepts, time frames) for aquatic ecosystems and built on knowledge stemming from different sources (i.e. WISE, BISE, Member State reporting within different policy processes, modelling) to develop innovative management tools, concepts, and business models (i.e. indicators, maps, ecosystem assessments, participatory approaches, mechanisms for promoting the delivery of ecosystem services) for aquatic ecosystems at various scales of space and time and relevant to different ecosystem types.

[Interventional catheter treatment of tricuspid valve regurgitation]. / Katheterinterventionelle Therapie der Trikuspidalklappeninsuffizienz.

BACKGROUND: The tricuspid valve can be considered the "forgotten" valve because in the past hardly any research has been conducted in this field and as a result only few therapeutic options existed. The prognosis of untreated tricuspid regurgitation (TR) is poor and mortality is high for patients with severe TR. Patients frequently return to medical practices and hospitals because of cardiac decompensation, with shortness of breath and leg edema. OBJECTIVE: Recent years have seen more development in catheter-based treatment options. Currently, several devices are in clinical evaluation, which are presented in this article. MATERIAL AND METHODS: A web-based literature search was carried out and information was gathered at international cardiology meetings (TCT 2016 in Washington, DGK 2017 in Mannheim, EuroPCR 2017 in Paris). RESULTS AND CONCLUSION: There are various options for interventional catheter procedures for TR, which are being investigated within the scope of clinical studies. Most aim at reducing the tricuspid annular diameter and optimizing leaflet coaptation. Because of these new therapy options patients can now be treated who were considered untreatable in the past because of the high perioperative mortality.

Impact of surface condition and roughness on sediment formation: an experimental sewer system operated with real wastewater.

Regular sewer cleaning in North Rhine-Westphalia (Germany) generates annual costs of around 50 million Euros. This leads to the question of whether and to what extent sewer cleaning is necessary. To determine the effect of roughness, sewer surface condition and discharge, experiments with real wastewater were performed, using a sewer test track with acrylic glass tubes (DN 300) prepared with abrasive paper and nature stone tiles at the wastewater treatment plant (WWTP) Bochum-Ölbachtal (Ruhrverband, Germany). A logarithmic relationship between deposit height and time was found to lead to maximum deposit heights of 5 to 60 mm. Surface structure analysis by texture measuring indicated that deposits within the first 28 days after cleaning are highly influenced by the surface condition of the sewer and not necessarily by roughness. Furthermore, under dry weather conditions deposit heights are nearly stable after this time, indicating the limiting effect of sewer cleaning. Deposit formation amounted to 1.75-1.80 mm/d at a roughness of ks = 0.10 mm (fine but catchy microstructure) and 0-0.1 mm/d at ks 1.25 mm (wavy microstructure) at steady state and transient discharge within the first 28 days after sewer cleaning.

Detection and Compensation of Periodic Motion in Magnetic Particle Imaging.

The temporal resolution of the tomographic imaging method magnetic particle imaging (MPI) is remarkably high. The spatial resolution is degraded for measured voltage signal with low signal-to-noise ratio, because the regularization in the image reconstruction step needs to be increased for system-matrix approaches and for deconvolution steps in x -space approaches. To improve the signal-to-noise ratio, blockwise averaging of the signal over time can be advantageous. However, since block-wise averaging decreases the temporal resolution, it prevents resolving the motion. In this paper, a framework for averaging motion-corrupted MPI raw data is proposed. The motion is considered to be periodic as it is the case for respiration and/or the heartbeat. The same state of motion is thus reached repeatedly in a time series exceeding the repetition time of the motion and can be used for averaging. As the motion process and the acquisition process are, in general, not synchronized, averaging of the captured MPI raw data corresponding to the same state of motion requires to shift the starting point of the individual frames. For high-frequency motion, a higher frame rate is potentially required. To address this issue, a binning method for using only parts of complete frames from a motion cycle is proposed that further reduces the motion artifacts in the final images. The frequency of motion is derived directly from the MPI raw data signal without the need to capture an additional navigator signal. Using a motion phantom, it is shown that the proposed method is capable of averaging experimental data with reduced motion artifacts. The methods are further validated on in-vivo data from mouse experiments to compensate the heartbeat.

[Future interventional procedures for valve diseases]. / Zukünftige interventionelle Verfahren bei Herzklappenerkrankungen.

BACKGROUND: Percutaneous valve therapies represent one of the most innovative areas within interventional cardiology in the past 10 years. AIM: The aim of this work is to give an overview of current and upcoming therapeutic options. MATERIALS AND METHODS: In this manuscript, the results of a retro- and prospective literature research are summarized. RESULTS AND DISCUSSION: With the introduction of percutaneous therapies for valvular heart disease, patients who were previously considered too ill for surgery can now be treated. The percutaneous treatment of aortic or mitral valve disease has become standard therapy. Likewise, promising results have been obtained for percutaneous treatment options for pathologies of the tricuspid valve, which are still under intense investigation.

[Mitral valve interventions: Where do we stand?]. / Mitralklappeninterventionen : Wo stehen wir?

Mitral valve regurgitation (MR) with resulting heart failure is one of the most prevalent types of valvular heart disease. Currently, various approaches to catheter-based therapy of MR are already available for patients deemed to be at high-risk for surgery. Most experience has been gained with the MitraClip® system. Technological developments in the field of catheter-based treatment of MR is advancing at a rapid pace, with treatment modalities suited for patients with both primary and secondary MR. Annuloplasty is the surgical gold standard, particularly for patients with secondary MR. For catheter-based therapy of secondary MR a distinction is made between indirect and direct annuloplasty, with the latter most closely corresponding to surgical ring implantation. Catheter-based mitral valve replacement is technically feasible at present; however, experience is still limited and only few reports have been published. Technological development is markedly slower than in the field of transcatheter aortic valve replacement, predominantly owing to the far more complex structure of the mitral valve. Positive experience has already been gained with catheter-based implantation of prostheses designed for the aortic valve into degenerated mitral valve bioprostheses and failed surgical mitral annuloplasty rings (valve-in-valve and valve-in-ring implantation). Further approaches to catheter-based treatment of MR in high-risk surgical patients are expected in the future.

Cardiac remodeling following percutaneous mitral valve repair - initial results assessed by cardiovascular magnetic resonance imaging.

PURPOSE: Percutaneous mitral valve repair with the MitraClip device (Abbott Vascular, Redwood City, California, USA) is a novel therapeutic option in patients with mitral regurgitation. This study evaluated the feasibility of cardiac volume measurements by cardiovascular magnetic resonance imaging (CMR) to assess reverse myocardial remodeling in patients after MitraClip implantation. MATERIALS AND METHODS: 12 patients underwent CMR at baseline (BL) before and at 6 months follow-up (FU) after MitraClip implantation. Cine-CMR was performed in short- and long-axes for the assessment of left ventricular (LV), right ventricular (RV) and left atrial (LA) volumes. RESULTS: Assessment of endocardial contours was not compromised by the device-related artifact. No significant differences in observer variances were observed for LV, RV and LA volume measurements between BL and FU. LV end-diastolic (median 127 [IQR 96 - 150] vs. 112 [86 - 150] ml/m(2); p = 0.03) and LV end-systolic (82 [54 - 91] vs. 69 [48 - 99] ml/m(2); p = 0.03) volume indices decreased significantly from BL to FU. No significant differences were found for RV end-diastolic (94 [75 - 103] vs. 99 [77 - 123] ml/m(2); p = 0.91), RV end-systolic (48 [42 - 80] vs. 51 [40 - 81] ml/m(2); p = 0.48), and LA (87 [55 - 124] vs. 92 [48 - 137] ml/m(2); p = 0.20) volume indices between BL and FU. CONCLUSION: CMR enables the assessment of cardiac volumes in patients after MitraClip implantation. Our CMR findings indicate that percutaneous mitral valve repair results in reverse LV but not in RV or LA remodeling. KEY POINTS: • Volume measurements by cardiovascular magnetic resonance imaging are feasible following percutaneous mitral valve repair despite device-related artifacts.• A significant reduction of left ventricular volume was found in terms of beneficial, reverse left ventricular remodeling after 6-month follow-up.• No significant reduction was found in right ventricular or left atrial volumes after percutaneous mitral valve repair after 6-month follow-up.

[Quality of documentation of intraoperative and postoperative complications : improvement of documentation for a nationwide quality assurance program and comparison with routine data]. / Dokumentationsqualität intra- und postoperativer Komplikationen : Verbesserung der Dokumentation für die verpflichtende Qualitätssicherung und Vergleich mit DRG-Routinedaten.

INTRODUCTION: Complications after cholecystectomy are continuously documented in a nationwide database in Germany. Recent studies demonstrated a lack of reliability of these data. The aim of the study was to evaluate the impact of a control algorithm on documentation quality and the use of routine diagnosis coding as an additional validation instrument. METHODS: Completeness and correctness of the documentation of complications after cholecystectomy was compared over a time interval of 12 months before and after implementation of an algorithm for faster and more accurate documentation. Furthermore, the coding of all diagnoses was screened to identify intraoperative and postoperative complications. RESULTS AND DISCUSSION: The sensitivity of the documentation for complications improved from 46 % to 70 % (p = 0.05, specificity 98 % in both time intervals). A prolonged time interval of more than 6 weeks between patient discharge and documentation was associated with inferior data quality (incorrect documentation in 1.5 % versus 15 %, p < 0.05). The rate of case documentation within the 6 weeks after hospital discharge was clearly improved after implementation of the control algorithm. Sensitivity and specificity of screening for complications by evaluating routine diagnoses coding were 70 % and 85 %, respectively. The quality of documentation was improved by implementation of a simple memory algorithm.

[Evaluation of data on surgical complications after cholecystectomy submitted to a nationwide quality assurance program (BQS) in Germany]. / Qualität der BQS-Dokumentation: Datenevaluation anhand intra- und postoperativer Komplikationen nach Cholezystektomien.

BACKGROUND: The BQS is a nationwide quality assurance program in Germany. The aim was to evaluate the data quality on intra-operative and postoperative complications for cholecystectomy submitted to the BQS. PATIENTS AND METHODS: For 205 patients who underwent cholecystectomy in 2007 complications were retrospectively evaluated and compared with those documented in the BQS database. Additionally the risk factors for complications were documented. RESULTS: A total of 205 patients were included in the study. In 88% of patients the operations were initiated as laparoscopy and the conversion rate was 8.3%. Of the patients 28 suffered from intra-operative or postoperative complications. There were no injuries to the ductus hepatocholedochus (DHC). The most common operation-specific complications were disorders in wound healing (n=7). Multivariate analyses resulted in significant increases in complication rates for ASA status (Odds ratio 3.29, 95% confidence interval 2.12-5.10, p<0.01) and acute cholecystitis (odds ratio 7.71, 9% confidence interval 2.96-20.08, p<0.01). Only 13 patients out of 28 were correctly documented in the BQS database (p<0.01). Sensitivity and specificity for complications were 46 and 98%, respectively. CONCLUSIONS: Less than half of all cases were correctly documented in the BQS database. If documentation inthe BQS database was equally poor for all German surgical departments, neither benchmarking nor general conclusions on quality of surgical care could be drawn from the BQS data.

Diffusion tensor imaging-based fractional anisotropy quantification in the corticospinal tract of patients with amyotrophic lateral sclerosis using a probabilistic mixture model.

BACKGROUND AND PURPOSE: In amyotrophic lateral sclerosis (ALS), fiber degeneration within the corticospinal tract (CST) can be quantified by diffusion tensor imaging (DTI) as an indirect marker of upper motor neuron involvement. A new method of measuring quantitative DTI parameters using a probabilistic mixture model for fiber tissue and background in the corticospinal tract of patients with ALS is evaluated. MATERIALS AND METHODS: Axial echo-planar imaging (EPI) DTI datasets (6 gradient directions, 10 repetitions) were acquired for 10 patients and 20 healthy control subjects. The diffusion tensor was visualized in a multiplanar viewer using a unique color coding method. Pure fiber tissue inside a region is separated from background and mixture voxels using a probabilistic mixture model. This allows for a reduction of errors as a result of partial volume effects and measurement variability. RESULTS: Fractional anisotropy (FA) was measured within the CST at levels ranging from internal capsule to pons. Mean coefficients of variation of intrarater, scan-rescan, and inter-rater reproducibility were 2.4%, 3.0%, and 5.7%, respectively. Optimal measurement positions along the CST with respect to minimum variability and maximum difference between patients and healthy subjects were identified in the caudal half of the internal capsule. Moreover, a negative correlation between the age-corrected FA and the disease duration but not the ALS Severity scale score was found. CONCLUSION: The new software for fiber integrity quantification is suited to assess FA in the corticospinal tract with high reproducibility. Thus, this tool can be useful in future studies for monitoring disease status and potential treatment efficiency.

Coronary restenosis after implantation of drug-eluting stents.

Randomized trials comparing drug-eluting stents (DES) with bare-metal stents have shown that the former significantly reduce the incidence of angiographic and clinical restenosis into an unprecedented low, one-digit, range. However, post-DES restenosis is not zero. Next to incomplete coverage with DES of the vessel segment injured by balloon angioplasty, factors such as stent underexpansion, stent overexpansion, and nonuniform distribution of stent struts have been associated with post-DES restenosis. Current evidence suggests that inadequate, though predominantly focal, delivery of the antiproliferative agent (sirolimus or paclitaxel) into the vessel wall is likely the common cause of post-DES restenosis. There is no consensus at present on how to treat post-DES restenosis. Long-term results reported to date on small numbers of patients undergoing interventional treatment for post-DES restenosis appear to be worse than outcomes observed after the index intervention, regardless of whether another DES was implanted or not, and warrant further study.

Detection of tumour infiltration in axonal fibre bundles using diffusion tensor imaging.

We present a method for the detection and quantification of white matter infiltration from human brain tumours based on Diffusion Tensor Imaging (DTI). Since white matter destruction alters the local diffusion properties, DTI has the potential to sensitively detect tumour infiltration and to quantify the degree thereof. Here, we consider three tumour patients with gliomas, two with and one without contralateral tumour progress. We use DTI to identify specific fibre systems, where infiltration has to be assessed. On this basis, the problem of arbitrary region of interest definition is solved such that tumour infiltration can be reliably quantified in particular fibre bundles. It is demonstrated at the Corpus Callosum (CC) and the Pyramidal Tract (PT) that fibre bundle infiltration can be well detected by specific visualisation techniques of diffusion tensor data. Infiltration of the CC is quantified by using a reliable method for the determination of diffusion properties inside particular fibre bundles. For an age normalised quantification of white matter infiltration we introduce the Integrity Index, which measures the diffusion anisotropy inside an infiltrated fibre bundle normalised by the diffusion anisotropy in a specific region of healthy fibre tissue. It turns out that the quantification of CC infiltration correlates with contralateral tumour progression and has the potential to serve as a surrogate marker for this process, which is crucial for surgical therapy decisions and intervention planning.

[Twist-guided thread control: a technique for faster and atraumatic continuous sutures]. / Fortlaufende Nähte mit Fadendrill -- Eine Zeit sparende und schonende Operationstechnik.

A simple technique by twisting the thread in clockwise or counter clockwise direction before tightening the suture can help to produce a regular vascular suture line. In a blinded experiment with 60 vascular anastomosis it was proved that the time needed for suture can be reduced by 15%, and that traumatic touch with surgical instruments can be diminished by 63%.

[Diffusion tensor imaging. Theory, sequence optimization and application in Alzheimer's disease]. / Diffusions-Tensor-Bildgebung. Theorie, Sequenzoptimierung und Anwendungen bei Morbus Alzheimer.

Diffusion tensor imaging (DTI) offers an in vivo view into the microarchitecture of the brain. Furthermore it allows a three-dimensional reconstruction of fiber tracts. We will discuss the principles of DTI and possibilities for sequence optimization. Finally we will give an overview of DTI and its application in Alzheimer's disease.