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Single-cell RNA sequencing (scRNA-Seq) has emerged as a powerful tool for understanding cellular heterogeneity and function. However the choice of sample multiplexing reagents can impact data quality and experimental outcomes. In this study, we compared various multiplexing reagents, including MULTI-Seq, Hashtag antibody, and CellPlex, across diverse sample types such as human peripheral blood mononuclear cells (PBMCs), mouse embryonic brain and patient-derived xenografts (PDXs). We found that all multiplexing reagents worked well in cell types robust to ex vivo manipulation but suffered from signal-to-noise issues in more delicate sample types. We compared multiple demultiplexing algorithms which differed in performance depending on data quality. We find that minor improvements to laboratory workflows such as titration and rapid processing are critical to optimal performance. We also compared the performance of fixed scRNA-Seq kits and highlight the advantages of the Parse Biosciences kit for fragile samples. Highly multiplexed scRNA-Seq experiments require more sequencing resources, therefore we evaluated CRISPR-based destruction of non-informative genes to enhance sequencing value. Our comprehensive analysis provides insights into the selection of appropriate sample multiplexing reagents and protocols for scRNA-Seq experiments, facilitating more accurate and cost-effective studies.

The emergence of large language models (LLMs) and assisted artificial intelligence (AI) technologies have revolutionized the way in which we interact with technology. A recent symposium at the Walter and Eliza Hall Institute explored the current practical applications of LLMs in medical research and canvassed the emerging ethical, legal and social implications for the use of AI-assisted technologies in the sciences. This paper provides an overview of the symposium's key themes and discussions delivered by diverse speakers, including early career researchers, group leaders, educators and policy-makers highlighting the opportunities and challenges that lie ahead for scientific researchers and educators as we continue to explore the potential of this cutting-edge and emerging technology.

Microglia regulate multiple processes in the central nervous system, exhibiting a considerable level of cellular plasticity which is facilitated by an equally dynamic transcriptional environment. While many gene networks that regulate microglial functions have been characterised, the influence of epigenetic regulators such as small non-coding microRNAs (miRNAs) is less well defined. We have sequenced the miRNAome and mRNAome of mouse microglia during brain development and adult homeostasis, identifying unique profiles of known and novel miRNAs. Microglia express both a consistently enriched miRNA signature as well as temporally distinctive subsets of miRNAs. We generated robust miRNA-mRNA networks related to fundamental developmental processes, in addition to networks associated with immune function and dysregulated disease states. There was no apparent influence of sex on miRNA expression. This study reveals a unique developmental trajectory of miRNA expression in microglia during critical stages of CNS development, establishing miRNAs as important modulators of microglial phenotype.

BACKGROUND: Selective neck dissection (SND) is the surgical treatment of choice in squamous cell carcinoma of the head and neck (HNSCC) with suspected or manifest metastases in the cervical lymph nodes. For SND to be successful, treated lymph node levels should be selected according to anatomic considerations and the extent of the disease. Aim of this study was to identify neck dissection levels that had an impact on individual prognosis. METHODS: We conducted a retrospective review of SND as part of primary treatment of HNSCC. Overall survival (OS) and regional control rates (RCR) were calculated for all patients treated at one academic tertiary referral center. RESULTS: 661 patients with HNSCC were included, 644 underwent ipsilateral and 319 contralateral SND. Average follow-up was 78.9 ± 106.4 months. 67 (10.1%) patients eventually developed nodal recurrence. Tumor sites were oral cavity (135), oropharynx (179), hypopharynx (118) and larynx (229). Tumor categories pT1-pT4a, and all clinical and pathological nodal categories were included. Multivariate analysis indicated improved OS rates for patients undergoing SND in ipsilateral levels I and V as well as level III contralaterally. Analysis for tumor origin showed that SND in ipsilateral level I showed significantly improved OS in HNSCC of the oral cavity. CONCLUSION: The dissection of ipsilateral level I in oral cavity cancer was of particular relevance in our exploratory, retrospective analysis. To clarify the relevance for the determination of the extent of SND, this should be investigated prospectively in a more homogenous patient cohort.

Dupilumab has been shown to be safe and effective in treating chronic rhinosinusitis with polyposis (CRSwNP). There is to this date no published data whether subgroups like patients with aspirin exacerbated respiratory disease (AERD), increased histologic eosinophilia or elevated blood eosinophil or IgE-levels benefit greater from dupilumab therapy. Moreover, there is no data comparing the efficacy of functional endoscopic sinus surgery (FESS) with dupilumab therapy. We conducted a retrospective chart review of all patients that were treated at a tertiary referral center for CRswNP with dupilumab. We also contacted the patients with a questionnaire to evaluate the efficacy of previous surgeries and dupilumab therapy by visual analogue scale (VAS) and the glasgow benefit inventory (GBI) as well as report on side effects. Overall, 75 patients were included in the study at hand that reported back 138 times. While dupilumab treatment was efficient, we found no systematic evidence of greater efficacy of dupilumab in patients with AERD, histologic eosinophilia or increased blood eosinophil or IgE-levels. All patients showed a considerable decrease in subjective burden of disease, objective smell tests and endoscopic findings. From the patients point of view, dupilumab therapy showed greater efficacy both in the VAS and the GBI overall and all subcategories but "social support." Dupilumab is efficient in treating CRSwNP; this effect is independent from disease characteristics like AERD, histologic eosinophilia, serum IgE-levels or eosinophil counts. There seems to be a group of patients that benefit greater from dupilumab therapy compared to FESS.

Background In the spring of 2020 during the first wave of the pandemic an above-average number of residents and staff in nursing homes fell ill and accounted for the highest number of incidences. Due to the pandemic, managers in nursing homes had to make new decisions on a daily basis as well as interpret and integrate decisions made by higher level authorities. Aim of the study The aim was to describe the decisions that had to be made by the managers of nursing homes in dealing with the COVID-19 pandemic and related consequences. Material and methods A qualitative multicentre cross-sectional design was chosen. Data collection was conducted with semi-structured telephone interviews. The recorded audio data were transcribed, analyzed using the framework analysis method and reflected in peer debriefings. Results A total of 78 interviews were conducted in 43 nursing homes and 3 main themes with 10 subthemes emerged: decisions about social participation, decisions on quarantine and isolation and staff adjustments. Discussion Clearer information and directives for the implementation of measures are needed, e.g. through standardized guidelines nationwide. Additionally, public health departments should play a stronger and more responsible role in a pandemic situation. The consequences of their decisions were hardly foreseeable for the managers and were marked by uncertainty. Responsibilities for and consequences of pandemic-related decisions should be further evaluated to empower managers in times of crises.

The Dot/Icm system of Legionella pneumophila is essential for virulence and delivers a large repertoire of effectors into infected host cells to create the Legionella containing vacuole. Since the secretion of effectors via the Dot/Icm system does not occur in the absence of host cells, we hypothesised that host factors actively participate in Dot/Icm effector translocation. Here we employed a high-throughput, genome-wide siRNA screen to systematically test the effect of silencing 18,120 human genes on translocation of the Dot/Icm effector, RalF, into HeLa cells. For the primary screen, we found that silencing of 119 genes led to increased translocation of RalF, while silencing of 321 genes resulted in decreased translocation. Following secondary screening, 70 genes were successfully validated as 'high confidence' targets. Gene set enrichment analysis of siRNAs leading to decreased RalF translocation, showed that ubiquitination was the most highly overrepresented category in the pathway analysis. We further showed that two host factors, the E2 ubiquitin-conjugating enzyme, UBE2E1, and the E3 ubiquitin ligase, CUL7, were important for supporting Dot/Icm translocation and L. pneumophila intracellular replication. In summary, we identified host ubiquitin pathways as important for the efficiency of Dot/Icm effector translocation by L. pneumophila, suggesting that host-derived ubiquitin-conjugating enzymes and ubiquitin ligases participate in the translocation of Legionella effector proteins and influence intracellular persistence and survival.

OBJECTIVE: To evaluate the effect of Lipopolysaccharide (LPS), a bacterial endotoxin on cochlear microcirculation, and its mode of action. METHODS: Twenty-five Dunkin-Hartley guinea pigs were divided into five groups of five animals each. After surgical preparation, cochlear microcirculation was quantified by in vivo fluorescence microscopy. Placebo or LPS (1 mg, 10 µg, and 100 ng) was applied topically, and microcirculation was measured before and twice after application. A fifth group was pretreated with etanercept, a tumor necrosis factor (TNF) antagonist, and afterward the lowest LPS concentrations that yielded significant results (10 µg) were applied. RESULTS: In the groups that had been treated with 1 mg and 10 µg LPS, a significant drop in cochlear microcirculation was observed after 30 (.791 ± .089 Arbitrary Units (AU), compared to baseline, and .888 ± .071AU) and 60 (.756 ± .101 AU and .817 ± .124 AU, respectively) minutes. The groups that had been treated with 100 ng LPS and that had been pretreated with etanercept showed no significant change in cochlear blood flow compared to placebo. CONCLUSION: Lipopolysaccharide shows a dose-dependent effect on cochlear microcirculation; this effect can already be observed after 30 min. Pretreatment with etanercept can abrogate this effect, indicating that TNF mediates the effect of LPS on cochlear microcirculation.

PURPOSE: Adenocarcinoma of the salivary glands is of low incidence and a broad range of histopathological subtypes. Cancer stem cell markers (CSC) might serve as novel prognostic parameters. To date, only a few studies examined the expression of CSC in adenocarcinoma of the salivary glands with diverging results. To further investigate the reliability in terms of prognostic value, a histopathological analysis of CSCs on a cohort of patients with adenocarcinomas of the major salivary glands was performed. METHODS: Tumor samples of 40 consecutive patients with adenocarcinoma of the major salivary gland treated with curative intend at one tertiary center were stained with the CSCs ALDH1, BMI-1, CD44, Nanog, and SOX2. Expression of these markers was correlated with clinicopathological parameters and survival estimates. RESULTS: Correlation of high expression of ALDH1 with higher grading (p < 0.001) and high expression of CD44 with the localization of the neoplasm (p = 0.05), larger tumor size (p = 0.006), positive pN-category (p = 0.023), and advanced UICC stage (p = 0.002) was found. Furthermore, high expression of SOX2 correlated with a negative perineural invasion (p = 0.02). No significant correlation of any investigated marker with survival estimates was observed. CONCLUSION: In conclusion, our study did not find a significant correlation of the investigated CSCs with survival estimates in adenocarcinoma of the major salivary glands. Recapitulating the results of our study in conjunction with data in the literature, the CSCs ALDH1, BMI-1, CD44, Nanog, and SOX2 do not seem to serve as reliable prognostic parameters in the treatment of adenocarcinoma of the salivary glands.

OBJECTIVES: Patients with multiple myeloma (MM) are at increased risk for infection. Clinical assessment of infection risk is increasingly challenging in the era of immune-based therapy. A pilot systems-level immune analysis study to identify predictive markers for infection was conducted. METHODS: Patients with relapsed and/or refractory MM (RRMM) who participated in a treatment trial of lenalidomide and dexamethasone were evaluated. Data on patient demographics, disease and episodes of infection were extracted from clinical records. Peripheral blood mononuclear cells (PBMCs) collected at defined intervals were analysed, with or without mitogen re-stimulation, using RNA sequencing and mass cytometry (CyTOF). CyTOF-derived cell subsets and RNAseq gene expression profiles were compared between patients that did and did not develop infection to identify immune signatures that predict infection over a 3-month period. RESULTS: Twenty-three patients participated in the original treatment trial, and we were able to access samples from 17 RRMM patients for further evaluation in our study. Nearly half the patients developed an infection (8/17) within 3 months of sample collection. Infections were mostly clinically diagnosed (62.5%), and the majority involved the respiratory tract (87.5%). We did not detect phenotypic or numerical differences in immune cell populations between patients that did and did not develop infections. Transcriptional profiling of stimulated PBMCs revealed distinct Th2 immune pathway signatures in patients that developed infection. CONCLUSION: Immune cell counts were not useful predictors of infection risk. Functional assessment of stimulated PBMCs has identified potential immune profiles that may predict future infection risk in patients with RRMM.

PURPOSE: It has been established that the infection with SARS-CoV-2 may cause an impairment of chemosensory function. However, there is little data on the long-term effects of SARS-CoV-2 infection on chemosensory function. METHODS: Twenty three SARS-CoV-2-positive patients diagnosed in spring 2020 with subjective hyposmia (out of 57 positive patients, 40.3%) were compared to SARS-CoV-2-positive patients without hyposmia (n = 19) and SARS-CoV-2-negative patients (n = 14). Chemosensory function was assessed by the Brief Smell Identification Test (BSIT), Taste Strips (TS), Visual Analogue Scales (VAS), and the SNOT-22. The initial cohort with hyposmia were also examined at 8 weeks and 6 months after initial examination. RESULTS: There were no differences between the SARS-CoV-2-positive cohort without hyposmia and negative controls in terms of BSIT (8.5 ± 2.6 vs. 10.2 ± 1.8), TS (3.4 ± 0.6 vs. 3.9 ± 0.3) or VAS (2.1 ± 1.3 vs. 1.1 ± 0.5); yet the SNOT-22 was significantly elevated (27.7 ± 11.2 vs. 16.4 ± 10.8). The SARS-CoV-2-positive group with hyposmia performed significantly poorer in BSIT (4.0 ± 1.7 vs. 8.5 ± 2.6/10.2 ± 1.8), TS (2.6 ± 1.3 vs. 3.4 ± 0.6/3.9 ± 0.3), and VAS (7.9 ± 2.2 vs. 2.1 ± 1.3/1.1 ± 0.5) compared to both control groups. At week 8 and month 6 control, six and five patients, respectively, still suffered from subjectively and objectively impaired chemosensory function. The other patients had recovered in both respects. CONCLUSION: SARS-CoV-2 patients with subjectively impaired chemosensory function regularly perform poorly in objective measurements. About 70% of patients suffering from olfactory dysfunction in SARS-CoV-2 quickly recover-the rest still suffers from considerable impairment 6 months after infection.

MOTIVATION: Bioinformatic analysis of single-cell gene expression data is a rapidly evolving field. Hundreds of bespoke methods have been developed in the past few years to deal with various aspects of single-cell analysis and consensus on the most appropriate methods to use under different settings is still emerging. Benchmarking the many methods is therefore of critical importance and since analysis of single-cell data usually involves multi-step pipelines, effective evaluation of pipelines involving different combinations of methods is required. Current benchmarks of single-cell methods are mostly implemented with ad-hoc code that is often difficult to reproduce or extend, and exhaustive manual coding of many combinations is infeasible in most instances. Therefore, new software is needed to manage pipeline benchmarking. RESULTS: The CellBench R software facilitates method comparisons in either a task-centric or combinatorial way to allow pipelines of methods to be evaluated in an effective manner. CellBench automatically runs combinations of methods, provides facilities for measuring running time and delivers output in tabular form which is highly compatible with tidyverse R packages for summary and visualization. Our software has enabled comprehensive benchmarking of single-cell RNA-seq normalization, imputation, clustering, trajectory analysis and data integration methods using various performance metrics obtained from data with available ground truth. CellBench is also amenable to benchmarking other bioinformatics analysis tasks. AVAILABILITY AND IMPLEMENTATION: Available from https://bioconductor.org/packages/CellBench.

BACKGROUND: Epistaxis is one of the more common reasons for emergency room visits. The main risk factor for epistaxis is anticoagulant therapy. Until recently, the main culprit was oral intake of a vitamin K antagonist, such as warfarin, which has a number of side effects. Even more recently, several direct oral anticoagulants, rivaroxaban and dabigatran, have been approved for use. We investigated the possible differences between treatment of epistaxis with direct oral anticoagulants and vitamin K antagonists. METHODS: We conducted a retrospective cohort study at a tertiary referral center in Germany. All patients who were admitted within a 1-year period were included. Patient files were used to obtain the information. RESULTS: Overall, 677 patients were included in our study. Of these, 159 had been treated with vitamin K antagonists and 49 with direct oral anticoagulants. There were no significant differences in terms of age (p = 0.592), sex (p = 0.372), vital signs, bloodwork, or location of bleeding (p = 0.372). Management of epistaxis between the groups was also comparable (p = 0.399), with similar hospital admission rates (37.1% vs 24.5%; p = 0.145) and duration of stay (3.5 ± 2.1 days vs 3.8 ± 3.3 days; p = 0.650). CONCLUSION: We found no evidence to suggest epistaxis is more severe or requires more invasive therapy in patients given direct oral anticoagulants. A significant proportion of patients on vitamin K antagonists were not within the target range for international normalized ratio, highlighting one of the main issues with oral anticoagulation by vitamin K antagonists.

The epilepsies affect around 65 million people worldwide and have a substantial missing heritability component. We report a genome-wide mega-analysis involving 15,212 individuals with epilepsy and 29,677 controls, which reveals 16 genome-wide significant loci, of which 11 are novel. Using various prioritization criteria, we pinpoint the 21 most likely epilepsy genes at these loci, with the majority in genetic generalized epilepsies. These genes have diverse biological functions, including coding for ion-channel subunits, transcription factors and a vitamin-B6 metabolism enzyme. Converging evidence shows that the common variants associated with epilepsy play a role in epigenetic regulation of gene expression in the brain. The results show an enrichment for monogenic epilepsy genes as well as known targets of antiepileptic drugs. Using SNP-based heritability analyses we disentangle both the unique and overlapping genetic basis to seven different epilepsy subtypes. Together, these findings provide leads for epilepsy therapies based on underlying pathophysiology.

Background: The commercially available 10x Genomics protocol to generate droplet-based single cell RNA-seq (scRNA-seq) data is enjoying growing popularity among researchers. Fundamental to the analysis of such scRNA-seq data is the ability to cluster similar or same cells into non-overlapping groups. Many competing methods have been proposed for this task, but there is currently little guidance with regards to which method to use. Methods: Here we use one gold standard 10x Genomics dataset, generated from the mixture of three cell lines, as well as multiple silver standard 10x Genomics datasets generated from peripheral blood mononuclear cells to examine not only the accuracy but also running time and robustness of a dozen methods. Results: We found that Seurat outperformed other methods, although performance seems to be dependent on many factors, including the complexity of the studied system. Furthermore, we found that solutions produced by different methods have little in common with each other. Conclusions: In light of this we conclude that the choice of clustering tool crucially determines interpretation of scRNA-seq data generated by 10x Genomics. Hence practitioners and consumers should remain vigilant about the outcome of 10x Genomics scRNA-seq analysis.

Periventricular nodular heterotopia (PVNH) is a malformation of cortical development commonly associated with epilepsy. We exome sequenced 202 individuals with sporadic PVNH to identify novel genetic risk loci. We first performed a trio-based analysis and identified 219 de novo variants. Although no novel genes were implicated in this initial analysis, PVNH cases were found overall to have a significant excess of nonsynonymous de novo variants in intolerant genes (p = 3.27x10-7), suggesting a role for rare new alleles in genes yet to be associated with the condition. Using a gene-level collapsing analysis comparing cases and controls, we identified a genome-wide significant signal driven by four ultra-rare loss-of-function heterozygous variants in MAP1B, including one de novo variant. In at least one instance, the MAP1B variant was inherited from a parent with previously undiagnosed PVNH. The PVNH was frontally predominant and associated with perisylvian polymicrogyria. These results implicate MAP1B in PVNH. More broadly, our findings suggest that detrimental mutations likely arising in immediately preceding generations with incomplete penetrance may also be responsible for some apparently sporadic diseases.

BACKGROUND: The pathogenesis of neurological and mental health disorders often involves multiple genes, complex interactions, as well as brain- and development-specific biological mechanisms. These characteristics make identification of disease genes for such disorders challenging, as conventional prioritisation tools are not specifically tailored to deal with the complexity of the human brain. Thus, we developed a novel web-application-brain-coX-that offers gene prioritisation with accompanying visualisations based on seven gene expression datasets in the post-mortem human brain, the largest such resource ever assembled. RESULTS: We tested whether our tool can correctly prioritise known genes from 37 brain-specific KEGG pathways and 17 psychiatric conditions. We achieved average sensitivity of nearly 50%, at the same time reaching a specificity of approximately 75%. We also compared brain-coX's performance to that of its main competitors, Endeavour and ToppGene, focusing on the ability to discover novel associations. Using a subset of the curated SFARI autism gene collection we show that brain-coX's prioritisations are most similar to SFARI's own curated gene classifications. CONCLUSIONS: brain-coX is the first prioritisation and visualisation web-tool targeted to the human brain and can be freely accessed via http://shiny.bioinf.wehi.edu.au/freytag.s/ .

OBJECTIVE: To evaluate the performance of an in silico prioritization approach that was applied to 179 epileptic encephalopathy candidate genes in 2013 and to expand the application of this approach to the whole genome based on expression data from the Allen Human Brain Atlas. METHODS: PubMed searches determined which of the 179 epileptic encephalopathy candidate genes had been validated. For validated genes, it was noted whether they were 1 of the 19 of 179 candidates prioritized in 2013. The in silico prioritization approach was applied genome-wide; all genes were ranked according to their coexpression strength with a reference set (i.e., 51 established epileptic encephalopathy genes) in both adult and developing human brain expression data sets. Candidate genes ranked in the top 10% for both data sets were cross-referenced with genes previously implicated in the epileptic encephalopathies due to a de novo variant. RESULTS: Five of 6 validated epileptic encephalopathy candidate genes were among the 19 prioritized in 2013 (odds ratio = 54, 95% confidence interval [7,∞], p = 4.5 × 10(-5), Fisher exact test); one gene was false negative. A total of 297 genes ranked in the top 10% for both the adult and developing brain data sets based on coexpression with the reference set. Of these, 9 had been previously implicated in the epileptic encephalopathies (FBXO41, PLXNA1, ACOT4, PAK6, GABBR2, YWHAG, NBEA, KNDC1, and SELRC1). CONCLUSIONS: We conclude that brain gene coexpression data can be used to assist epileptic encephalopathy gene discovery and propose 9 genes as strong epileptic encephalopathy candidates worthy of further investigation.

BACKGROUND: In the past decade, the identification of gene co-expression has become a routine part of the analysis of high-dimensional microarray data. Gene co-expression, which is mostly detected via the Pearson correlation coefficient, has played an important role in the discovery of molecular pathways and networks. Unfortunately, the presence of systematic noise in high-dimensional microarray datasets corrupts estimates of gene co-expression. Removing systematic noise from microarray data is therefore crucial. Many cleaning approaches for microarray data exist, however these methods are aimed towards improving differential expression analysis and their performances have been primarily tested for this application. To our knowledge, the performances of these approaches have never been systematically compared in the context of gene co-expression estimation. RESULTS: Using simulations we demonstrate that standard cleaning procedures, such as background correction and quantile normalization, fail to adequately remove systematic noise that affects gene co-expression and at times further degrade true gene co-expression. Instead we show that a global version of removal of unwanted variation (RUV), a data-driven approach, removes systematic noise but also allows the estimation of the true underlying gene-gene correlations. We compare the performance of all noise removal methods when applied to five large published datasets on gene expression in the human brain. RUV retrieves the highest gene co-expression values for sets of genes known to interact, but also provides the greatest consistency across all five datasets. We apply the method to prioritize epileptic encephalopathy candidate genes. CONCLUSIONS: Our work raises serious concerns about the quality of many published gene co-expression analyses. RUV provides an efficient and flexible way to remove systematic noise from high-dimensional microarray datasets when the objective is gene co-expression analysis. The RUV meth

Extended traumatic wounds require extended reconstructive operations and are accompanied by long hospitalizations and risks of infection, thrombosis and flap loss. In particular, the frequently used Topical Negative Pressure (TNP) Therapy is regarded as cost-intensive. The costs of TNP in the context of traumatic wounds is analyzed using the method of health economic evaluation. All patients (n=67: 45 male, 22 female; average age 54 y) with traumatically acquired wounds being treated with TNP at the university hospital of Goettingen in the period 01/01/2005-31/12/2007 comprise the basis for this analysis. The concept of activity-based costing based on clinical pathways according to InEK (National Institute for the Hospital Remuneration System) systematic calculations was chosen for cost accounting. In addition, a special module system adaptable for individual courses of disease was developed. The treated wounds were located on a lower extremity in 83.7% of cases (n=56) and on an upper extremity in 16.3% of cases (n=11). The average time of hospitalization of the patients was 54 days. Twenty-five patients (37.31%) exceeded the "maximum length of stay" of their associated DRG (Diagnosis Related Groups). The total PCCL (patient clinical complexity level = patient severity score) of 2.99 reflects the seriousness of disease. For the treatment of the 67 patients, total costs were $1,729,922.32 (1,249,176.91 Euro). The cost calculation showed a financial deficit of $-210,932.50 (-152,314.36 Euro). Within the entire treatment costs of $218,848.07 (158,030.19 Euro), 12.65% per case were created by TNP with material costs of $102,528.74 (74,036 Euro), representing 5.92% of entire costs. The cost of TNP per patient averaged $3,266.39 (2,358.66 Euro). The main portion of the costs was not - as is often expected - due to high material costs of TNP but instead to long-term treatments. Because of their complexity, the cases are insufficiently represented in the lump-sum calculatio, Ausgedehnte traumatische Weichteildefekte erfordern aufwändige rekonstruktive Operationsverfahren und sind von langen Liegezeiten und Risiken wie Infektion, Thrombose und Lappenverlusten gekennzeichnet. Die Vakuumtherapie (VAC) stellt dabei eine wesentliche und häufig angewandte Therapie dar, die als kostenintensiv angesehen wird. Die Kosten dieser Vakuumtherapie in der Behandlung des traumatischen Weichteildefekts werden in der vorliegenden Arbeit mit der Methodik der gesundheitsökonomischen Evaluation analysiert. Alle Patienten (n=67: 45 m, 22 w; Ø 54 J.) mit traumatischem Weichteildefekt, die zwischen 01/01/2005-31/12/2007 an der Universitätsklinik Göttingen mit VAC behandelt wurden, wurden in die Evaluation eingeschlossen. Die Methode der Prozesskostenrechnung anhand Klinischer Pfade, welche sich an der InEK (Institut für das Entgeltsystem im Krankenhaus)-Systematik orientiert, war Grundlage dieser Kalkulation. Zusätzlich wurde ein neues Modulsystem entwickelt, welches es ermöglichte, individuelle Patientenkarrieren exakt abzubilden. Die behandelten Weichteildefekte waren in 83,7% der Fälle (n=56) an der oberen Extremität und in 16,3% der Fälle (n=11) an der unteren Extremität lokalisiert. Die durchschnittliche Liegezeit betrug 54 Tage. 25 Patienten (37,31%) überschritten die obere Grenzverweildauer ihrer assoziierten DRG (Diagnosebezogene Fallgruppen). Der PCCL (patientenbezogener Gesamtschweregrad)-Wert von 2.99 zeigt den hohen Schweregrad dieses Kollektivs an. Für die Behandlung dieser 67 Patienten entstanden Kosten von 1.249.176,91 Euro. Die Kosten-Erlöskalkulation zeigte eine Negativbilanz von -152.314,36 Euro. Die Kosten für die VAC Behandlung betrugen 158,030.19 Euro (12,65%) mit Materialkostenanteil von 5,92% (74.036 Euro). Die Gesamtkosten pro Patient für die VAC Therapie betrugen 2.358,66 Euro. Der Hauptanteil der entstehenden Behandlungskosten bestand nicht, wie häufig angenommen, aus den Materialkosten für die VAC Behandlung, sondern in den langen Li