Etablierung und Validierung von diagnostischen Standards bei implantatassoziierten Infektionen der Wirbelsäulenchirurgie

Einleitung. In den letzten Jahren wurde ein stetiger Anstieg bei der Durchführung instrumentierter Wirbelsäuleneingriffe beobachtet. Daraus resultiert allerdings auch eine Häufung der Notwendigkeit für eine Revisionsoperation. Eine Ursache dafür kann neben aseptischem Implantatversagen eine Infektion sein. Besonders sogenannte Low-grade-Infektionen, die häufig implantatassoziiert sind, lassen sich oftmals nur schwer diagnostizieren und stellen eine Herausforderung im klinischen Alltag dar. Ziel dieser Arbeit ist es deshalb, den Anteil von implantatassoziierten Infektionen bei Revisionsoperationen zu bestimmen, mögliche Risikofaktoren zu identifizieren, verschiedene diagnostische Hilfsmittel zu vergleichen und einen Überblick über die identifizierten Erreger zu geben. Methodik. Bei dieser Arbeit handelt es sich um eine prospektive Beobachtungsstudie. Implantatassoziierte Infektionen wurden anhand der Richtlinien der Centers for Disease Control and Prevention (CDC) diagnostiziert und eingeteilt. Es wurden unterschiedliche Anzeichen eines Infektes auf ihre Aussagekraft untersucht und bewertet und die Sensitivität und Spezifität von Sonikation und Gewebeprobe ermittelt und miteinander verglichen. Ergebnisse. Insgesamt wurden 118 Patienten in die Studie eingeschlossen. Bei 39 Patienten wurde eine Infektion diagnostiziert, davon 35 implantatassoziiert und vier mit reinen Wundinfektionen. Als Risikofaktor wurde die Anzahl vorherig operierter Segmente identifiziert. Zudem zeigte sich, dass Infektionen signifikant häufiger zu einer Revisionsoperation innerhalb des ersten Jahres nach dem letzten Eingriff führten als aseptische Ursachen. Klinische, labormedizinische, intraoperative und radiologische Infektionszeichen stellten sich als nicht ausreichend sensitiv für die Identifizierung einer implantatassoziierten Infektion heraus. Die mikrobiologische Untersuchung von intraoperativ gewonnenem Material zeigte hingegen eine gute Sensitivität und Spezifität. Für die Sonikation wurde eine Sensitivität von 94,3 % und für die Gewebeprobe eine Sensitivität von 68,6 % für implantatassoziierte Infektionen ermittelt. Die Spezifität betrug 98,7 % für die Sonikation und 96,2 % für die Gewebeprobe. Die am häufigsten nachgewiesenen Erreger waren Koagulase-negative Staphylokokken (KNS), insbesondere Staphylococcus epidermidis und Propionibacterium acnes. Schlussfolgerung. Implantatassoziierte Infektionen sind eine häufige Ursache für Revisionsoperationen an der Wirbelsäule. Sie zu erkennen, ist präoperativ schwierig und oftmals nicht eindeutig möglich. Daher ist die Untersuchung von intraoperativ gewonnenem Material notwendig, um eine zuverlässige Diagnose zu gewährleisten und „stumme“ Infektionen zu erkennen. Dabei zeigt die Sonikation bessere Ergebnisse als die periimplantäre Gewebeprobe. Allerdings sollten stets mehrere Parameter in die Beurteilung einfließen, um eine Infektion sicher diagnostizieren zu können. Da die häufigsten Erreger einer implantatassoziierten Infektion Bakterien der physiologischen Hautflora sind, kommt der Prävention durch eine sterile intra- und postoperative Behandlung große Bedeutung zu.Introduction. The number of instrumented spine surgery has been increasing over the last decades. Consequently, revision spine surgery is also more often than it used to be. In addition to aseptic failure, another reason for such revision spine surgeries may be infection. Especially low-grade spinal implant infections are frequently difficult to diagnose and may challenge the practitioner. Therefore, the aim of this study was to detect the number of spinal infections in revision spine surgery, identify risk factors for it, compare different diagnostic tools for infections and show the most frequent microorganisms in spinal implant infections. Methods. This study is a prospective follow-up study. Spinal implant infections were diagnosed and categorized by the criteria of the Centers for Disease Control and prevention (CDC). Different signs of an infection were analyzed and sensitivity and specificity for sonicate fluid culture and peri-implant tissue culture were calculated and compared. Results. In total 118 patients were included in this study. In 39 patients infection was diagnosed, 35 of them showed spinal implant infection and 4 of them showed superficial or deep wound infection without involvement of implants. As risk factor for spinal implant infections, the number of previous surgeries included segments was identified. Furthermore, infection was more often within one year after previous spine surgery than aseptic failure. Clinical, laboratory, intraoperative and radiological signs of infection didn´t show acceptable sensitivity for the diagnosis of infection. Microbiological and histopathological analyzing of intraoperatively explanted materials showed good results for sensitivity in diagnosis of a spinal implant infection. Sonicate fluid had sensitivity of 94,3 % and peri-implant tissue culture had sensitivity of 68,6 %. Specificity for spinal implant infection were 98,7 % for sonicate fluid and 96,2 % for peri-implant tissue culture. Most frequent microorganisms identified at revision spine surgery were Coagulase-negative staphylococci and Propionibacterium acnes. Conclusion. Spinal implant infection is frequently found in revision spine surgery. Preoperative tools often miss diagnosis of such an infection. Therefore, analyzing of explanted material while revision spine surgery is often needed to detect postoperative spinal infections. In comparison, sonicate fluid shows better results than peri-implant tissue culture. However, it seems useful to use all available parameters for a solid diagnosis of postoperative spinal infection. The most frequent microorganisms of spinal implant infection are part of physiological skin microbiome. Therefore, there should be a special focus on preventing spinal implant infection by a sterile treatment before and after surgery

An energy-economic analysis of real-world hybrid building energy systems

A coordinated operation of decentralised micro-scale hybrid energy systems within a locally managed network such as a district or neighbourhood will play a significant role in the sector-coupled energy grid of the future. A quantitative analysis of the effects of the primary energy factors, energy conversion efficiencies, load profiles, and control strategies on their energy-economic balance can aid in identifying important trends concerning their deployment within such a network. In this contribution, an analysis of the operational data from five energy laboratories in the trinational Upper-Rhine region is evaluated and a comparison to a conventional reference system is presented. Ten exemplary data-sets representing typical operation conditions for the laboratories in different seasons and the latest information on their national energy strategies are used to evaluate the primary energy consumption, CO2 emissions, and demand-related costs. Various conclusions on the ecologic and economic feasibility of hybrid building energy systems are drawn to provide a toe-hold to the engineering community in their planning and development

Prenatal human skin expresses the antimicrobial peptide RNase 7

Antimicrobial peptides and proteins (AMPs) play important roles in skin immune defense due to their capacity to inhibit growth of microbes. During intrauterine life, the skin immune system has to acquire the prerequisites to protect the newborn from infection in the hostile environment after birth, which includes the production of skin AMPs. The aim of this study was to analyze the expression of RNase 7, HBD-2/3 and psoriasin during human skin development, thus, providing a deeper insight about the maturity of a fundamental component of the innate immune system. We found low RNase 7 expression levels in the periderm but no expression of HBD-2/3 and psoriasin in first trimester human skin using immunohistochemistry. At the end of the second trimester, RNase 7 is expressed weakly in all epidermal layers with a marked signal in the stratum corneum. HBD-3 and psoriasin are focally expressed while HBD-2 is not detectable. Analysis of supernatants from cultured prenatal skin cells showed that in contrast to adult control, RNase 7 and psoriasin are not found in prenatal skin, suggesting that AMPs are detectable but are not secreted. This study shows the differential expression of AMPs in developing, non-perturbed human prenatal skin. It is conceivable that the combined expression of RNase 7, HBD-3 and psoriasin in fetal skin constitutes a developmental program to exert a broad spectrum of antimicrobial activity to maintain sterility in the amniotic cavity

Cryo-EM structures reveal intricate Fe-S cluster arrangement and charging in Rhodobacter capsulatus formate dehydrogenase

Metal-containing formate dehydrogenases (FDH) catalyse the reversible oxidation of formate to carbon dioxide at their molybdenum or tungsten active site. They display a diverse subunit and cofactor composition, but structural information on these enzymes is limited. Here we report the cryo-electron microscopic structures of the soluble Rhodobacter capsulatus FDH (RcFDH) as isolated and in the presence of reduced nicotinamide adenine dinucleotide (NADH). RcFDH assembles into a 360 kDa dimer of heterotetramers revealing a putative interconnection of electron pathway chains. In the presence of NADH, the RcFDH structure shows charging of cofactors, indicative of an increased electron load

Structural insights into Cullin4-RING ubiquitin ligase remodelling by Vpr from simian immunodeficiency viruses

Viruses have evolved means to manipulate the host's ubiquitin-proteasome system, in order to down-regulate antiviral host factors. The Vpx/Vpr family of lentiviral accessory proteins usurp the substrate receptor DCAF1 of host Cullin4-RING ligases (CRL4), a family of modular ubiquitin ligases involved in DNA replication, DNA repair and cell cycle regulation. CRL4DCAF1 specificity modulation by Vpx and Vpr from certain simian immunodeficiency viruses (SIV) leads to recruitment, poly-ubiquitylation and subsequent proteasomal degradation of the host restriction factor SAMHD1, resulting in enhanced virus replication in differentiated cells. To unravel the mechanism of SIV Vpr-induced SAMHD1 ubiquitylation, we conducted integrative biochemical and structural analyses of the Vpr protein from SIVs infecting Cercopithecus cephus (SIVmus). X-ray crystallography reveals commonalities between SIVmus Vpr and other members of the Vpx/Vpr family with regard to DCAF1 interaction, while cryo-electron microscopy and cross-linking mass spectrometry highlight a divergent molecular mechanism of SAMHD1 recruitment. In addition, these studies demonstrate how SIVmus Vpr exploits the dynamic architecture of the multi-subunit CRL4DCAF1 assembly to optimise SAMHD1 ubiquitylation. Together, the present work provides detailed molecular insight into variability and species-specificity of the evolutionary arms race between host SAMHD1 restriction and lentiviral counteraction through Vpx/Vpr proteins

Evaluation of early-phase [F-18]-florbetaben PET acquisition in clinical routine cases

Objectives: In recent years several [F-18]-labelled amyloid PET tracers have been developed and have obtained clinical approval. There is accumulating evidence that early (post injection) acquisitionswith these tracers are equally informative as conventional blood flow andmetabolismstudies for diagnosis of Alzheimer's disease, but there have been few side-by-side studies. Therefore, we investigated the performance of early acquisitions of [F-18]florbetaben (FBB) PET compared to [F-18]-fluorodeoxyglucose (FDG) PET in a clinical setting. Methods: All subjects were recruited with clinical suspicion of dementia due to neurodegenerative disease. FDG PET was undertaken by conventional methods, and amyloid PET was performed with FBB, with early recordings for the initial 10 min (early-phase FBB), and late recordings at 90-110 min p.i. (late-phase FBB). Regional SUVR with cerebellar and globalmean normalization were calculated for early-phase FBB and FDG PET. Pearson correlation coefficients between FDG and early-phase FBB were calculated for predefined cortical brain regions. Furthermore, a visual interpretation of disease pattern using 3-dimensional stereotactic surface projections (3DSSP) was performed, with assessment of intra-reader agreement. Results: Among a total of 33 patients (mean age 67.5 +/- 11.0 years) included in the study, 18 were visually rated amyloid-positive, and 15 amyloid-negative based on late-phase FBB scans. Correlation coefficients for earlyphase FBB vs. FDG scans displayed excellent agreement in all target brain regions for global mean normalization. Cerebellar normalization gave strong, but significantly lower correlations. 3D representations of early-phase FBB visually resembled the corresponding FDG PET images, irrespective of the amyloid-status of the late FBB scans. Conclusions: Early-phase FBB acquisitions correlate on a relative quantitative and visual level with FDG PET scans, irrespective of the amyloid plaque density assessed in late FBB imaging. Thus, early-phase FBB uptake depicts a metabolism-like image, suggesting it as a valid surrogatemarker for synaptic dysfunction, which could ultimately circumvent the need for additional FDG PET investigation in diagnosis of dementia. (C) 2016 The Author(s). Published by Elsevier Inc

AgriWeedClim database: A repository of vegetation plot data from Central European arable habitats over 100 years

Aims: Arable habitats (i.e. fields, orchards, vineyards, and their fallows) were cre- ated by humans and have been essential elements in Central European landscapes for several millennia. In recent decades, these habitats have been drastically altered by changes in land use as well as agricultural practices and, more recently, by climate change. These changes have precipitated substantial changes in vegetation and their spatial and temporal trajectories have not yet been exhaustively studied. Here, we present the AgriWeedClim database —­ a new resource of vegetation plot (relevé) data of arable habitats in Central Europe. Location: Germany, Czech Republic, Slovakia, Switzerland, Liechtenstein, Austria, Hungary, Northern Italy, Slovenia, Croatia. Methods: Vegetation plot data were obtained from large repositories (e.g. European Vegetation Archive), specialized regional databases, colleagues and the literature. Data were then checked for completeness and standardized (e.g. taxonomy, nomenclature, crop types). Species were assigned native, archaeophyte (i.e. alien species introduced before c. 1492 CE) or neophyte (i.e. alien species introduced after c. 1492 CE) status. Results: The AgriWeedClim database version 1.0 contains georeferenced data from 32,889 vegetation plots sampled from 1916 to 2019. Conclusions: We provide an overview of this new resource and present example analyses to show its content and possible applications. We outline potential research questions including analysis of patterns and causes of vegetation changes in arable habitats from the early 20th century to the present

Structural mechanism of CRL4-instructed STAT2 degradation via a novel cytomegaloviral DCAF receptor

Human cytomegalovirus (CMV) is a ubiquitously distributed pathogen whose rodent counterparts such as mouse and rat CMV serve as common infection models. Here, we conducted global proteome profiling of rat CMV-infected cells and uncovered a pronounced loss of the transcription factor STAT2, which is crucial for antiviral interferon signalling. Via deletion mutagenesis, we found that the viral protein E27 is required for CMV-induced STAT2 depletion. Cellular and in vitro analyses showed that E27 exploits host-cell Cullin4-RING ubiquitin ligase (CRL4) complexes to induce poly-ubiquitylation and proteasomal degradation of STAT2. Cryo-electron microscopy revealed how E27 mimics molecular surface properties of cellular CRL4 substrate receptors called DCAFs (DDB1- and Cullin4-associated factors), thereby displacing them from the catalytic core of CRL4. Moreover, structural analyses showed that E27 recruits STAT2 through a bipartite binding interface, which partially overlaps with the IRF9 binding site. Structure-based mutations in M27, the murine CMV homologue of E27, impair the interferon-suppressing capacity and virus replication in mouse models, supporting the conserved importance of DCAF mimicry for CMV immune evasion

Analysing reduced tillage practices within a bio-economic modelling framework

Sustainable Intensification of agricultural production systems will require changes in farm practice. Within arable cropping systems, reducing the intensity of tillage practices (e.g. reduced tillage) potentially offers one such sustainable intensification approach. Previous researchers have tended to examine the impact of reduced tillage on specific factors such as yield or weed burden, while, by definition, sustainable intensification necessitates a system-based analysis approach. Drawing upon a bio-economic optimisation model, ‘MEETA’, we quantify trade-off implications between potential yield reductions, reduced cultivation costs and increased crop protection costs. We extend the MEETA model to quantify farm-level net margin, in addition to quantifying farm-level gross margin, net energy, and greenhouse gas emissions. For the lowest intensity tillage system, zero tillage, results demonstrate financial benefits over a conventional tillage system even when the zero tillage system includes yield penalties of 0-14.2% (across all crops). Average yield reductions from zero tillage literature range from 0-8.5%, demonstrating that reduced tillage offers a realistic and attainable sustainable intensification intervention, given the financial and environmental benefits, albeit that yield reductions will require more land to compensate for loss of calories produced, negating environmental benefits observed at farm-level. However, increasing uptake of reduced tillage from current levels will probably require policy intervention; an extension of the recent changes to the CAP (‘Greening’) provides an opportunity to do this