University of Freiburg
  • Freiburg, Baden-Württemberg, Germany
Recent publications
The escalating prevalence of anterior cruciate ligament (ACL) injuries in sports necessitates innovative strategies for ACL reconstruction. In this study, we propose a multiphasic bone-ligament-bone (BLB) integrated scaffold as a potential solution. The BLB scaffold comprised two polylactic acid (PLA)/deferoxamine (DFO)@mesoporous hydroxyapatite (MHA) thermally induced phase separation (TIPS) scaffolds bridged by silk fibroin (SF)/connective tissue growth factor (CTGF)@Poly(l-lactide-co-ε-caprolactone) (PLCL) nanofiber yarn braided scaffold. This combination mimics the native architecture of the ACL tissue. The mechanical properties of the BLB scaffolds were determined to be compatible with the human ACL. In vitro experiments demonstrated that CTGF induced the expression of ligament-related genes, while TIPS scaffolds loaded with MHA and DFO enhanced the osteogenic-related gene expression of bone marrow stem cells (BMSCs) and promoted the migration and tubular formation of human umbilical vein endothelial cells (HUVECs). In rabbit models, the BLB scaffold efficiently facilitated ligamentization and graft-bone integration processes by providing bioactive substances. The double delivery of DFO and calcium ions by the BLB scaffold synergistically promoted bone regeneration, while CTGF improved collagen formation and ligament healing. Collectively, the findings indicate that the BLB scaffold exhibits substantial promise for ACL reconstruction. Additional investigation and advancement of this scaffold may yield enhanced results in the management of ACL injuries.
Introduction: Mosquito-borne infections are of global health concern because of their rapid spread and upsurge, which creates a risk for coinfections. DENV and ZIKV are transmitted by Aedes aegypti and A. albopictus and are prevalent in Nigeria and neighbouring countries. However, their seroprevalence, burden, hidden endemicity and possible cocirculation are poorly understood in Nigeria. Methods: We conducted a cross-sectional study of 871 participants from three regions of Nigeria. All serum samples were analysed using malaria RDT and the immunoblot molecular diagnostic assay recomLine Tropical Fever for the presence of arboviral antibody serological marker IgG (Mikrogen Diagnostik, Neuried, Germany) with DENV and ZIKV Nonstructural protein 1 (NS 1), DENV and ZIKV Equad (variant of the envelope protein with designated mutations to increase specificity), according to the manufacturer's instructions. Results: The overall IgG antibody seropositivity against DENV-flavivirus was 44.7% (389/871); 95% CI (41.41-47.99), while ZIKV-flavivirus was 19.2% (167/871); 95% CI (0.16-0.21), and DENV-ZIKV-flavivirus cocirculation antibody seropositivity was 6.2%5 (54/871); 95% CI (0.6-0.7) in the three study regions of Nigeria. The study cohort presented similar clinical signs and symptoms of flaviviruses (DENV and ZIKV) in all three study regions. Conclusion: This study highlighted an unexpectedly high antibody seropositivity, burden, hidden endemicity, and regional spread of mono- and co-circulating flaviviruses (DENV and ZIKV) in Nigeria.Key messagesDengue flavivirus sero-cross-reactivity drives antibody-dependent enhancement of ZIKV infection.Both viruses share common hosts (humans) and vectors (primarily Aedes aegypti), and are thus influenced by similar biological, ecological, and economic factors, resulting in epidemiological synergy.Additionally, the actual burden in epidemic and interepidemic periods is grossly or chronically unknown and underreported. Despite this trend and the potential public health threat, there are no reliable data, and little is known about these arboviral co-circulation infections.
Design thinking has become a popular innovation approach in organizations globally. The request for design thinking (DT) training has increased in the past 10 years. However, the question remains if and how employees transfer their DT knowledge into their organization. In this study, we assess employees’ DT knowledge and DT application in an international company. We assume a gap between what employees know and apply, what we call the design thinking transfer gap. Furthermore, we assess employees’ perception of their own DT practice vs. the company’s DT practice. We find that on average, employees rate their knowledge of DT significantly higher than the extent of the application of DT in their work. Employees also perceive their individual practice of DT as higher than the company’s practice, indicating a potential mismatch between the organizational climate for innovation and employees’ capabilities. Our results call for further examination of the design thinking transfer gap. We discuss future research avenues and point out practical implications.
Purpose To map current literature and provide an overview of upcoming future diagnostic and prognostic methods for upper tract urothelial carcinoma (UTUC), including translational medical science. Methods A scoping review approach was applied to search the literature. Based on the published literature, and the experts own experience and opinions consensus was reached through discussions at the meeting Consultation on UTUC II in Stockholm, September 2022. Results The gene mutational profile of UTUC correlates with stage, grade, prognosis, and response to different therapeutic strategies. Analysis of pathway proteins downstream of known pathogenic mutations might be an alternative approach. Liquid biopsies of cell-free DNA may detect UTUC with a higher sensitivity and specificity than urinary cytology. Extracellular vesicles from tumour cells can be detected in urine and may be used to identify the location of the urothelial carcinoma in the urinary tract. 3D microscopy of UTUC samples may add information in the analysis of tumour stage. Chemokines and chemokine receptors were linked to overall survival and responsiveness to neoadjuvant chemotherapy in muscle-invasive bladder cancer, which is potentially also of interest in UTUC. Conclusion Current diagnostic methods for UTUC have shortcomings, especially concerning prognostication, which is important for personalized treatment decisions. There are several upcoming methods that may be of interest for UTUC. Most have been studied for urothelial carcinoma of the bladder, and it is important to keep in mind that UTUC is a different entity and not all methods are adaptable or applicable to UTUC.
Background Arrhythmias may originate from surgically unaffected right ventricular (RV) regions in patients with tetralogy of Fallot (TOF). We aimed to investigate action potential (AP) remodelling and arrhythmia susceptibility in RV myocardium of patients with repaired and with unrepaired TOF, identify possible correlations with clinical phenotype and myocardial fibrosis, and compare findings with data from patients with atrial septal defect (ASD), a less severe congenital heart disease. Methods Intracellular AP were recorded ex vivo in RV outflow tract samples from 22 TOF and three ASD patients. Arrhythmias were provoked by superfusion with solutions containing reduced potassium and barium chloride, or isoprenaline. Myocardial fibrosis was quantified histologically and associations between clinical phenotype, AP shape, tissue arrhythmia propensity, and fibrosis were examined. Results Electrophysiological abnormalities (arrhythmias, AP duration [APD] alternans, impaired APD shortening at increased stimulation frequencies) were generally present in TOF tissue, even from infants, but rare or absent in ASD samples. More severely diseased and acyanotic patients, pronounced tissue susceptibility to arrhythmogenesis, and greater fibrosis extent were associated with longer APD. In contrast, APD was shorter in tissue from patients with pre-operative cyanosis. Increased fibrosis and repaired-TOF status were linked to tissue arrhythmia inducibility. Conclusions Functional and structural tissue remodelling may explain arrhythmic activity in TOF patients, even at a very young age. Surprisingly, clinical acyanosis appears to be associated with more severe arrhythmogenic remodelling. Further research into the clinical drivers of structural and electrical myocardial alterations, and the relation between them, is needed to identify predictive factors for patients at risk. Graphical Abstract Central illustration: summary diagram of essential study results. Note that not all results are depicted here. For more detail, see text. APA action potential amplitude, APD action potential duration, AUC area under the curve, TOF tetralogy of Fallot.
Background Bone marrow (BM) transplantation is a life-saving therapy for hematological diseases, and the BM harbors also highly useful (progenitor) cell types for novel cell therapies manufacture. Yet, the BM collection technique is not standardized. Methods Benchmarking our collection efficiency to BM collections worldwide (N = 1248), we noted a great variability of total nucleated cell (TNC) yields in BM products (HPC-M) with superior performance of our center, where we have implemented a small volume aspirate policy. Thus, we next prospectively aimed to assess the impact of BM collection technique on HPC-M quality. For each BM collection (N = 20 donors), small volume (3 mL) and large volume (10 mL) BM aspirates were sampled at 3 time points and analyzed for cell composition. Results Compared to large volume aspirates, small volume aspirates concentrated more TNCs, immune cells, platelets, hematopoietic stem/progenitor cells, mesenchymal stromal cells (MSCs), and endothelial progenitors. Inversely, the hemoglobin concentration was higher in large volume aspirates indicating more hemoglobin loss. Manufacturing and dosing scenarios showed that small volume aspirates save up to 42% BM volume and 44% hemoglobin for HPC-M donors. Moreover, MSC production efficiency can be increased by more than 150%. Conclusions We propose to consider small volume BM aspiration as standard technique for BM collection.
Purpose The German ROP registry and its Europe‐wide successor, the EU‐ROP registry, collect data from patients treated for ROP. This analysis compares input parameters of these two registries to establish a procedure for joint analyses of different registry data using exemplary datasets from the two registries. Methods Exemplary datasets from the two databases over a 1‐year period each (German ROP Registry, 2011, 22 infants; EU‐ROP Registry, 2021, 44 infants) were compared. The parameters documented in the two databases were aligned and analysed regarding demographic parameters, treatment modalities, complications within first 24 h and retreatments. Results The current analysis showed that data can be aligned for joint analyses with some adjustments within the data structure. The registry with more detailed data collection (EU‐ROP) needs to be reduced regarding granularity in order to align the different registries, as the registry with lower granularity determines the level of analyses that can be performed in a comparative approach. In the exemplary datasets, we observed that the overall most common ROP severity in both registries was zone II, 3+ (2011: 70.5%; 2021: 65%), with decreasing numbers of clock hours showing preretinal neovascularisations (2011: 10–12 clock hours in 29% of cases, 2021: 4–6 clock hours in 38%). The most prevalent treatment method was laser coagulation in 2011 (75%) and anti‐VEGF therapy in 2021 (86.1%). Within the anti‐VEGF group, all patients were treated with bevacizumab in 2011 and with ranibizumab in 2021. Retreatment rates were comparable in 2011 and 2021. Conclusion Data from two different ROP registries can be aligned and jointly analysed. The analysis reveals a paradigm shift in treatment modalities, from predominantly laser to anti‐VEGF, and within the anti‐VEGF group from bevacizumab to ranibizumab in Germany. In addition, there was a trend towards earlier treatment in 2021.
In mammals, T cell development depends on the activity of the Foxn1 transcription factor in the thymic epithelium; mutations in the vertebrate‐specific Foxn1 gene are associated with profound T cell lymphopenia and fatal immunodeficiency. Here, we examined the extent of T cell development in teleosts lacking a functional foxn1 gene. In zebrafish carrying a deleterious internal deletion of foxn1 , reduced but robust lymphopoietic activity is maintained in the mutant thymus. Moreover, pseudogenization or loss of foxn1 in the genomes of deep‐sea anglerfishes is independent of the presence or absence of the canonical signatures of the T cell lineage. Thus, in contrast to the situation in mammals, the teleost thymus can support foxn1 ‐independent lymphopoiesis, most likely through the activity of the Foxn4 , an ancient metazoan paralog of Foxn1 . Our results imply that during early stages of vertebrate evolution, genetic control of thymopoiesis was functionally redundant and thus robust; in mammals, the genetic network was reorganized to become uniquely dependent on the FOXN1 transcription factor. This article is protected by copyright. All rights reserved
The nutritional adequacy of human milk (HM) from vegan/vegetarian mothers has been a matter of debate, and a variety of recommendations regarding the eligibility of these mothers as human milk donors exists. According to the latest evidence, HM from vegans/vegetarians is similar in its composition to that from omnivores, however, some differences may be observed regarding vitamin B 12 and omega‐3 fatty acids concentrations. Maternal supplementation of these compounds has been proven effective in increasing their HM concentration. With this survey, we aimed to explore the practices currently in use in European human milk banks (HMBs) regarding potential donors following vegan/vegetarian diets. The online survey was distributed to European HMBs between January and July 2022. A total of 188 HMBs were contacted, and 118 replied (response rate 63%). Vegan and vegetarian mothers were recommended supplements of vitamin B 12 to be accepted as donors in 27% and 26% of HMBs, respectively. Additional omega‐3 fatty acid supplementation was required in 8% HMBs. In the remaining HMBs, these mothers were either systematically excluded or included regardless of supplementation. The dosage of the recommended supplements was extremely variable. Fifty‐one percent of HMBs were following recommendations to guide their practice, national or local recommendations mainly. Great variability in European HMBs practices towards potential donors following vegan/vegetarian diets exists. Some of these practices can result in loss of donors and/or in potential nutritional deficiencies. Standardised evidence‐based recommendations on this issue and their implementation in daily HMB practice are needed.
Urban gardens have the potential to contribute to urban bee biodiversity. However, studies considering the effects of habitat amount and floral resources on bees using a functional approach, are largely lacking in Latin America, in particular in urban environments, where the potential competitive interactions between honeybees and wild bees deserve further attention. We evaluated how bee abundance and diversity, both taxonomic (richness, evenness) and functional (richness, evenness, and divergence of traits), are related to habitat amount in urban gardens (patch size, green cover in the surroundings), and the abundance and diversity of flowers (taxonomic and functional). We also examined the effect of the abundance of honeybees on urban wild bee communities. We selected 13 gardens within Córdoba city (Argentina) along an urbanization gradient based on vegetation cover, where we surveyed bee-flower interactions. We selected flower (i.e. morphology, color, and phenology) and bee (i.e. morphology, sociality, and diet) traits considered essential to plant-pollinator interactions to estimate flower and bee functional diversity, respectively. Bee taxonomic and functional diversity in urban gardens strongly depended on the floral species evenness, whereas the functional floral diversity and patch size, as well as the habitat amount at the landscape scale, did not significantly affect bee diversity. Moreover, the abundance of honeybees, once controlled by floral species evenness, did not influence the taxonomic structure of wild bee communities. Our results highlight that urban gardens can support functionally diverse bee communities, especially those with evenly distributed flower specie
Background To evaluate recurrence in patients with post-neoadjuvant pathological complete response (pCR) and in patients with complete response of primary tumor but persisting lymphatic spread of disease (non-pCR, ypT0ypN +) of esophageal cancer. Methods Seventy-five patients (63 pCR, 12 non-pCR) were analyzed retrospectively. Pattern and incidence of local and distant recurrence as well as the impact on overall (OS) and disease-free survival (DFS) were evaluated. The efficacy of neoadjuvant chemotherapy according to FLOT protocol was compared to neoadjuvant chemoradiation according to CROSS protocol. Results In the pCR group, isolated local recurrence was diagnosed in 3%, while no isolated local recurrence was observed in the non-pCR group due to the high incidence of distant recurrence. Distant recurrence was most common in both cohorts (isolated distant recurrence: pCR group 10% to non-pCR group 55%; simultaneous distant and local recurrence: pCR group 3% to non-pCR group 18%). Median time to distant recurrence was 5.5 months, and median time to local recurrence was 8.0 months. Cumulative incidence of distant recurrence (with and without simultaneous local recurrence) was 16% (± 6%) in pCR patients and 79% (± 13%) in non-pCR patients (hazard ratio (HR) 0.123) estimated by Kaplan–Meier method. OS (HR 0.231) and DFS (HR 0.226) were significantly improved in patients with pCR compared to patients with non-pCR. Advantages for FLOT protocol compared to CROSS protocol, especially with regard to distant control of disease (HR 0.278), were observed (OS (HR 0.361), DFS (HR 0.226)). Conclusion Distant recurrence is the predominant site of treatment failure in patients with pCR and non-pCR grade 1a regression, whereby recurrence rates are much higher in patients with non-pCR.
Purpose Protein-rich foods show heterogeneous associations with the risk of type 2 diabetes (T2D) and it remains unclear whether habitual protein intake is related to T2D risk. We carried out an umbrella review of systematic reviews (SR) of randomised trials and/or cohort studies on protein intake in relation to risks of T2D. Methods Following a pre-specified protocol (PROSPERO: CRD42018082395), we retrieved SRs on protein intake and T2D risk published between July 1st 2009 and May 22nd 2022, and assessed the methodological quality and outcome-specific certainty of the evidence using a modified version of AMSTAR 2 and NutriGrade, respectively. The overall certainty of evidence was rated according to predefined criteria. Results Eight SRs were identified of which six contained meta-analyses. The majority of SRs on total protein intake had moderate or high methodological quality and moderate outcome-specific certainty of evidence according to NutriGrade, however, the latter was low for the majority of SRs on animal and plant protein. Six of the eight SRs reported risk increases with both total and animal protein. According to one SR, total protein intake in studies was ~ 21 energy percentage (%E) in the highest intake category and 15%E in the lowest intake category. Relative Risks comparing high versus low intake in most recent SRs ranged from 1.09 (two SRs, 95% CIs 1.02–1.15 and 1.06–1.13) to 1.11 (1.05–1.16) for total protein (between 8 and 12 cohort studies included) and from 1.13 (1.08–1.19) to 1.19 (two SRs, 1.11–1.28 and 1.11–1.28) (8–9 cohort studies) for animal protein. However, SRs on RCTs examining major glycaemic traits (HbA1c, fasting glucose, fasting insulin) do not support a clear biological link with T2D risk. For plant protein, some recent SRs pointed towards risk decreases and non-linear associations, however, the majority did not support an association with T2D risk. Conclusion Higher total protein intake was possibly associated with higher T2D risk, while there is insufficient evidence for a risk increase with higher intakes of animal protein and a risk decrease with plant protein intake. Given that most SRs on plant protein did not indicate an association, there is possibly a lack of an effect.
Previous research suggests potential mitochondrial dysfunction and changes in fatty acid metabolism in a subgroup of individuals with autism spectrum disorder (ASD), indicated by higher lactate, pyruvate levels, and mitochondrial disorder prevalence. This study aimed to further investigate potential mitochondrial dysfunction in ASD by assessing blood metabolite levels linked to mitochondrial metabolism. Blood levels of creatine kinase (CK), alanine aminotransferase (ALT), aspartate aminotransferase (AST), lactate, pyruvate, free and total carnitine, as well as acylcarnitines were obtained in 73 adults with ASD (47 males, 26 females) and compared with those of 71 neurotypical controls (NTC) (44 males, 27 females). Correlations between blood parameters and psychometric ASD symptom scores were also explored. Lower CK ( p corr = 0.045) levels were found exclusively in males with ASD compared to NTC, with no such variation in females. ALT and AST levels did not differ significantly between both groups. After correction for antipsychotic and antidepressant medication, CK remained significant. ASD participants had lower serum lactate levels ( p corr = 0.036) compared to NTC, but pyruvate and carnitine concentrations showed no significant difference. ASD subjects had significantly increased levels of certain acylcarnitines, with a decrease in tetradecadienoyl‐carnitine (C14:2), and certain acylcarnitines correlated significantly with autistic symptom scores. We found reduced serum lactate levels in ASD, in contrast to previous studies suggesting elevated lactate or pyruvate. This difference may reflect the focus of our study on high‐functioning adults with ASD, who are likely to have fewer secondary genetic conditions associated with mitochondrial dysfunction. Our findings of significantly altered acylcarnitine levels in ASD support the hypothesis of altered fatty acid metabolism in a subset of ASD patients.
This contribution considers the problem of robust target localization using the possibly unreliable hybrid received signal strength and time-of-arrival measurements, in the Internet of Things (IoT) context. Traditional positioning approaches relying on either extra a priori error information for robustification or the computationally intensive convex programming techniques for optimization do not fit well into the IoT applications with limited computing resources. Such concerns, however, will jeopardize the straightforward applicability of many ready-made solutions to the IoT positioning services if left untreated. In this article, the problem is resolved in a different manner. We adopt here a Geman–McClure like loss function, which is much less sensitive to the biased sensor observations, in order to statistically robustify the $\ell _{2}$ -sapce-based location estimator. A computationally attractive iterative message passing algorithm is then developed to conduct efficient optimization. Simulation results demonstrate the performance superiority of the proposed scheme over its competitors in various localization environments.
Due to the rapid microbial degradation, Ethylene (ethene; C₂H₄) detection in most soils is difficult. The knowledge about factors favoring the occurrence of C₂H₄ is mainly based on labora-tory experiments which are not necessarily representative for real field conditions in forest soils. We report results from a total of 24 measuring plots in southwest-Germany and more than 50 000 gas samples, including long-term forest monitoring sites and other study sites in-volving liming, artificial soil compaction and temporary waterlogging. Many of the patterns and influencing factors identified in the laboratory were confirmed. In well-aerated forest soils, C₂H₄ was detected in 1.3% of the gas samples. C₂H₄ detection was higher at oxygen (O₂) con-centrations below 10% in the soil. The effect was positively correlated with bulk density in compacted soils and CO₂, CH₄ and N₂O concentrations - factors that indicate reduced microbial activity and thus also facilitate the detection of C₂H₄. It could be detected 3.5 times more often in spruce than in beech stands, indicating that plant species plays a role and was not found to follow any distinct spatial or temporal pattern with the exception of seemingly random spatio-temporal clusters of root-born C₂H₄ near large roots of spruce trees. The long observation peri-od and large dataset of this field study allowed valuable insights into C₂H₄ occurrence in forest soils under natural conditions supporting the theory that the plant hormone C₂H₄ is produced as a warning for anaerobic soil areas that are limiting root growth.
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9,740 members
Christopher Schlett
  • Department of Diagnostic and Interventional Radiology
Knut Holtsträter
  • Zentrum für Populäre Kultur und Musik (ZPKM)
Sonja-Verena Albers
  • Molecular Biology of Archaea
Ralf Reski
  • Chair Plant Biotechnology
Fahnenbergplatz, 79098, Freiburg, Baden-Württemberg, Germany
Head of institution
Prof. Dr. Kerstin Krieglstein
+49 761 203-0
+49 761 203-4369