22455 research outputs found
Sort by
Auswirkungen der Einführung eines Delir-Screeningverfahrens mit der Nursing-Delirium-Screening-Scale (Nu-DESC) im Aufwachraum
Get PDFBackground: Postoperative Delirium is common in the post-anesthesia caring unit (PACU). Our objective was to examine the effects of a newly introduced screening method in 2015 on the patient’s outcome and pharmaceuticals prescribed in the PACU.
Method: At the end of the recovery period, delirium was assessed using the Nursing Delirium Screening Scale Nu-DESC). Electronic records before (2010-2014) and after the introduction (2015-2017) of the screening were analyzed. Differences in medication use were detected through Mann-Whitney-U-test.
Results: Out of 45,266 patients, 1,031 (3.2%) developed delirium in the PACU. An increase in the administration of haloperidol (p≤0.01), clonidine (p≤0.01), lorazepam (p=0.02) and propofol (p≤0.01) was recorded after the introduction of Nu-DESC screening in contrast to midazolam (p=0.1) and dexamethasone (p=1.0), which remain unaffected. Mortality decreased from 1.0% to 0.6%. Contrary, patient´s length of stay in the PACU increased by 27 minutes (p≤0.01).
Conclusion: Significant increase in the administration of clonidine, haloperidol, and lorazepam, as well as the increased time in the patient's recovery room, indicate an adjusted delirium treatment induced by the screening procedure. The decrease in hospital mortality through the implementation of screenings was previously shown by Radtke et al [1]. Further studies to optimize the therapy of delirious patients in the recovery room are needed
The genetics of repeat disorders
Get PDFThe analysis of repetitive elements in the human genome remains a challenge in clinical genetics. As next-generation sequencing is limited in analyzing repeat disorders and complex regions within the human genome, specific diagnostic methods are required. This thesis describes (1) the implementation and validation of a long-read sequencing method for parallel repeat analysis of patients with adult-onset ataxia as well as (2) the analysis of the relevance of methylation profiles in the diagnosis and clinical evaluation of FSHD.
For a comprehensive repeat analysis of patients with adult-onset ataxia, clinical nanopore Cas9-targeted sequencing (Clin-CATS) was designed to cover the ten repeat disorders most frequently causing adult-onset ataxia in Germany (status when publishing manuscript 1): spinocerebellar ataxias (SCA) 1–3, 6–8, 17, RFC1 spectrum disorder, Friedreich’s ataxia (FRDA) and fragile-X-associated tremor/ataxia syndrome (FXTAS). Associated repeat loci are enriched using CRIPSR/Cas9 and subsequently sequenced using Oxford Nanopore Technology long-read sequencing. Sequencing data are used to derive repeat length, repeat sequence to identify repeat interruptions and the repeat composition of the RFC1 repeat array, as well as FMR1 promoter methylation. Repeat lengths obtained by Clin-CATS show a high concordance to those determined by conventional PCR-based repeat analysis. Pathogenic repeat expansions were reliably detected and the comprehensive set of parameters determined improved diagnostic precision of Clin-CATS over conventional repeat testing. The analysis of 100 patients with an adult-onset ataxia phenotype by Clin-CATS revealed causative repeat expansions in 28 patients, including rare conditions such as a very-late onset FRDA or a high-function FXTAS male carrying a non-methylated FMR1 promotor despite a fully expanded FMR1 repeat array. Clin-CATs highlights the high polymorphism of the RFC1 repeat array and reveals RFC1 spectrum disorder to be a frequent cause of hereditary adult-onset ataxia in Germany.
After verifying FSHD1 and FSHD2 patients as well as healthy individuals to significantly differ in the methylation patterns of their D4Z4 repeat arrays on chromosome 4q35, FSHD-MPA was established as a diagnostic method for diagnosing FSHD. Utilizing bisulfite conversion FSHD-MPA determines the methylation level of a region within the most distal D4Z4 repeat array of 4q35 alleles carrying the permissive haplotype (4qA or 4qAL, distal methylation) and the average methylation level of a second region present within each D4Z4 repeat unit of chromosome 4q35 (global methylation). Healthy individuals show global and distal hypermethylation, while FSHD1 patients show isolated distal hypomethylation and FSHD2 patients global and distal hypomethylation. Within a cohort of 148 patients with a clinical phenotype of FSHD or a positive family history of FSHD, methylation profiles are proven as precise diagnostic parameters for diagnosing FSHD by comparing the results from our epigenetic test with the results of Southern blotting and NGS sequencing of the epigenetic suppressor genes SMCHD1, DMNT3B and LRIF1 as well as the clinical phenotype. Furthermore FSHD1 and FSHD2 patients show an epigenetic overlap as some patients with global and distal hypomethylation have repeat contractions in the absence of pathogenic variants in known epigenetic suppressor genes. Methylation profiles allow to access the penetrance of genetic parameters indicating their potential in predictive testing. Distal methylation level and age-corrected clinical severity show high correlation level that are stronger than those of repeat length and age-corrected clinical severity in the cohort studied. As such distal methylation is a more precise and universal biomarker for disease severity in the present study accounting for FSHD1 as well as for FSHD2. Thus, the disease status of FSHD is better represented by epigenetic than by genetic parameters. Repeat contractions and pathogenic variants in epigenetic suppressor genes should be considered more as risk factors of the disease than as direct causes of the disease. Further refinements of FSHD diagnostics can be achieved by ONT long-read sequencing which yields all relevant diagnostic parameters within one analysis and specific for each allele including the methylation profile of the whole D4Z4 repeat locus
Mechanisms of neuronal pathology in a model of grey matter inflammation
Get PDFMultiple sclerosis (MS) is a chronic, inflammatory, and demyelinating disease of the central nervous system (CNS). It is characterized by formation of lesions both in white and grey matter. Upon disease evolution into progressive stages, grey matter pathology plays a larger role and permanent disability ensues.
Grey matter pathology of MS has been widely characterized through histopathological studies in terms of demyelination, neuronal pathology, and inflammation. However, the mechanisms that play a role in pathology development and progression are not fully understood. Furthermore, treatment options for progressive stages of MS are limited and we have no way of effectively blocking ongoing cortical neurodegeneration. Thus, my PhD project focused on modeling, visualizing, understanding, and therapeutic targeting of cortical grey matter pathology. To address these questions, I used a combination of confocal microscopy, multiphoton in vivo microscopy, bioinformatic transcriptomic analysis, CRISPR/Cas9 gene editing, and PET imaging.
The first part of my thesis aimed to establish a mouse model of grey matter pathology that resembled cortical pathology in MS. This model was induced in BiozziABH mice, which is a strain characterized by high antibody response and susceptibility to chronic CNS inflammation. Mice were immunized with MOG, followed by an intracerebral injection of pro-inflammatory cytokines to induce cortical lesions. Results suggest that our mouse model indeed presents with cortical grey matter demyelination, synapse loss and inflammatory lesions, which in turn, resembles previously described grey matter pathology in MS. Moreover, an age effect was observed in pathology resolution, with older mice displaying a more sustained neuroinflammatory response while younger mice spontaneously resolved inflammation. Further analysis of grey matter lesions revealed a potential role of synaptic calcium accumulation and phagocyte engulfment in neuronal pathology.
In the second part of the thesis, the focus was on investigating pathways and mechanisms underlying neuronal pathology in grey matter of MS. For this purpose, we utilized single nuclei transcriptomic analysis of our mouse model, which was further mapped together with data sets from MS patients. We aimed at determining a MS specific gene signature that was present both in our model as well as in patients with MS. To ensure MS specificity, we further analysed the enrichment of our cortical MS-related gene signature in an Alzheimer’s disease patient data set. Our results demonstrated a species conservation of a cortical MS-related gene signature with five genes that are highly upregulated in neurons in the inflamed cortex of mice and humans that are interesting targets for further mechanistic analysis.
We subsequently aimed to establish a CRISPR/Cas9 system for neuron-specific gene knockout which could then be used for investigation of mechanisms and pathways by which our candidate genes might play a role in MS pathology. Using two of the target genes, we demonstrated that the CRISPR/Cas9 system was successful in knocking out genes in neurons. However, we were up to now not able to conclusively resolve the role our selected genes played in MS grey matter pathology.
In the next part of my thesis, we aimed to test different therapeutic strategies in our mouse model to determine if they would inhibit neuronal pathology in the inflamed grey matter or could rescue existing pathology. We tested immunomodulatory therapies targeting microglia activation as a strategy to limit the induction of neuronal pathology and could show that CSF1R inhibition can prevent synapse loss in the cortical MS model.
Finally, we investigated imaging based approaches that could be used to track synaptic pathology in MS. For this purpose we performed a preclinical study with a SV2a specific PET tracer in our cortical MS model. PET imaging of mice demonstrated that the PET tracer was able to sensitively detect synapse loss in our model with the reduction in tracer uptake corresponding to the synaptic density decrease that was observed by histological examinations in situ.
Overall, the results obtained of my thesis provide new insights into the pathomechanisms undelying neuronal pathology in the grey matter, the therapeutic strategies that can be used to prevent it and the imaging strategies that can be used to track it in MS patients
Konventionelle und erweiterte Bildanalyse der 18F-FET-PET bei Gliomen: Evaluation von Radiomics bei 18F-FET negativen Gliomen
Get PDFModifikation eines hydraulischen Silikatzements (MTA) durch Zusatz von Gentamicin – Freisetzung und antimikrobielle Wirkung auf Biofilme zweier endodontologisch pathogener Bakterienspezies in vitro
Get PDFFKBP51 in a dynamic environment
Get PDFMental health disorders are a pressing global health-threat, affecting millions of people world-wide, which has already cost the world economy over 2.5 trillion dollars, making it a critical burden to society. These psychiatric disorders, including major depressive disorders, anxiety disorders and posttraumatic stress disorders, commonly arise as a combination of genetic and environmental factors. In the past decades, these gene by environment interactions (GxE) have increasingly been studied in both clinical and pre-clinical settings. Exposure to early life adversity has often been associated with negative outcomes on brain and behaviour and it has frequently been described as a risk factor for developing psychiatric disease. Nevertheless, there is also cumulative evidence that exposure to early life stress (ELS) in a milder form can result in adaptive responses that prepare an individual to cope with future life challenges. One gene that has repeatedly been implicated in the risk for psychiatric disease development is the FK506-binding protein 5 (FKBP5) gene, that encodes the glucocorticoid receptor (GR) co-chaperone FKBP51. FKBP51 plays an important role in regulating the sensitivity of the GR to the stress-hormone cortisol in humans or corticosterone in rodents. Interestingly, polymorphisms in the FKBP5 gene were found to interact with traumatic early life events to increase the risk for developing psychiatric disorders. In recent years, FKBP51 has extensively been studied in relation to stress resilience and vulnerability, however the mechanisms by which it contributes to these processes, particularly in combination with ELS, are not yet fully understood. Apart from genetic factors and early life events, there are a number of additional environmental factors that can be of great influence on mental health, such as age or sex. In fact, research from the past decades has shed an increasing light on the pivotal role that sex plays in the resilience to (early life) stress. Nevertheless, since many studies historically only included males, there is unfortunately still a large gap in information on the female sex when it comes to stress resilience and vulnerability mechanisms. In this thesis, the importance of including both sexes in rodent stress research study designs is emphasized, by demonstrating sex-differential phenotypes of chronic social defeat stress using a recently developed hands-on protocol for chronic social defeat in females. Moreover, using genetic mouse models, this thesis demonstrates not only clear sex-dependent, but also cell-type specific functionality of FKBP51, either under baseline conditions in an older aged sample or in interaction with ELS stress exposure. Furthermore, it underlines the FKBP51-mediated beneficial effects of ELS exposure in female mice and proposes novel underlying pathways in this process. Ultimately, this thesis corroborates the notion that FKBP5 is not per se a psychiatric risk factor, but rather a highly dynamic stress-responsive gene that interacts with the environment in shaping stress resilience
Proteomic insights into spliceosome components involved in antisense transcription at DNA breaks
Get PDF
The onset of secular evolution in the universe
Get PDFDisc galaxies build up their mass in a two-phase scenario. At higher redshifts, external processes dominate the evolution of the galaxy. With the expansion of the Universe and the decrease in the frequency of interactions, these external processes give place to the internal development of the galaxy, including disc formation and settling. However, it is unclear when this transition occurs in the Universe. Once the disc settles, at least partially, it is often prone to developing a non-axisymmetric structure, namely the bar. One of the immediate effects due to the presence of the bar is the gas inflow towards central parts of the galaxy, leading to central star formation and the building of a new rotationally-supported stellar structure, i.e., the nuclear disc. Therefore, we can estimate the cosmic epoch of bar formation (and thus the transition time in the two-phase scenario) by deriving the star formation history of the nuclear disc. In this thesis, we present the first generally applicable methodology to derive the time of bar formation for a sizeable sample of galaxies and, additionally, we share the first results from applying this methodology to 19 galaxies observed with the MUSE integral field spectrograph on the VLT (mostly from the TIMER survey).
Our methodology consists in carefully isolating the contribution of the nuclear disc to the observed spectra, in order to derive its star formation history free of contamination from other co-spatial stellar structures. To ascertain the uncertainties involved, particularly of a systematic nature, we run a thorough series of tests, leading to realistic error estimates. Among our main results, we find a wide range of values of disc-settling epochs (0 ≤ z ≤ 6), which indicates this is an ongoing process in the Universe that has commenced substantially earlier than previously thought. Analysing the current stellar mass of the bar-hosting galaxy, we find no correlation with the bar age. This contradicts the downsizing scenario that predicts that the more massive galaxies assembled their mass first, forming their bars first. Regarding secular evolution, we find evidence that bars can grow over time (relative to the host galaxy). In addition, by analysing the evolution of the light fraction enclosed in the bar over time, we find evidence of angular momentum exchange across the galaxy, with the trapping by the bar of stars from the galaxy disc, which can e plain the bar growth.
This methodology allows us, for the first time, to test theoretical predictions regarding bar-driven evolution from an observational perspective, opening new lines of research in the near future
