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- ItemEffects of new beta-type Ti-40Nb implant materials, brain-derived neurotrophic factor, acetylcholine and nicotine on human mesenchymal stem cells of osteoporotic and non osteoporotic donors(San Francisco, CA : Public Library of Science (PLoS), 2018) Kauschke, V.; Gebert, A.; Calin, M.; Eckert, J.; Scheich, S.; Heiss, C.; Lips, K.S.Introduction Treatment of osteoporotic fractures is still challenging and an urgent need exists for new materials, better adapted to osteoporotic bone by adjusted Young’s modulus, appropriate surface modification and pharmaceuticals. Materials and methods Titanium-40-niobium alloys, mechanically ground or additionally etched and titanium-6-alu-minium-4-vanadium were analyzed in combination with brain-derived neurotrophic factor, acetylcholine and nicotine to determine their effects on human mesenchymal stem cells in vitro over 21 days using lactate dehydrogenase and alkaline phosphatase assays, live cell imaging and immunofluorescence microscopy. Results Cell number of human mesenchymal stem cells of osteoporotic donors was increased after 14 d in presence of ground titanium-40-niobium or titanium-6-aluminium-4-vanadium, together with brain-derived neurotrophic factor. Cell number of human mesenchymal stem cells of non osteoporotic donors increased after 21 d in presence of titanium-6-aluminium-4-vanadium without pharmaceuticals. No significant increase was measured for ground or etched titanium-40-niobium after 21 d. Osteoblast differentiation of osteoporotic donors was significantly higher than in non osteoporotic donors after 21 d in presence of etched, ground titanium-40-niobium or titanium-6-aluminium-4-vanadium accompanied by all pharmaceuticals tested. In presence of all alloys tested brain-derived neurotrophic factor, acetylcholine and nicotine increased differentiation of cells of osteoporotic donors and accelerated it in non osteoporotic donors. Conclusion We conclude that ground titanium-40-niobium and brain-derived neurotrophic factor might be most suitable for subsequent in vivo testing.
- ItemGuidance of mesenchymal stem cells on fibronectin structured hydrogel films(San Francisco, California, US : PLOS, 2014) Kasten, Annika; Naser, Tamara; Brüllhoff, Kristina; Fiedler, Jörg; Müller, Petra; Möller, Martin; Rychly, Joachim; Groll, Jürgen; Brenner, Rolf E.; Engler, Adam J.Designing of implant surfaces using a suitable ligand for cell adhesion to stimulate specific biological responses of stem cells will boost the application of regenerative implants. For example, materials that facilitate rapid and guided migration of stem cells would promote tissue regeneration. When seeded on fibronectin (FN) that was homogeneously immmobilized to NCO-sP(EO-stat-PO), which otherwise prevents protein binding and cell adhesion, human mesenchymal stem cells (MSC) revealed a faster migration, increased spreading and a more rapid organization of different cellular components for cell adhesion on fibronectin than on a glass surface. To further explore, how a structural organization of FN controls the behavior of MSC, adhesive lines of FN with varying width between 10 µm and 80 µm and spacings between 5 µm and 20 µm that did not allow cell adhesion were generated. In dependance on both line width and gaps, cells formed adjacent cell contacts, were individually organized in lines, or bridged the lines. With decreasing sizes of FN lines, speed and directionality of cell migration increased, which correlated with organization of the actin cytoskeleton, size and shape of the nuclei as well as of focal adhesions. Together, defined FN lines and gaps enabled a fine tuning of the structural organization of cellular components and migration. Microstructured adhesive substrates can mimic the extracellular matrix in vivo and stimulate cellular mechanisms which play a role in tissue regeneration.
- ItemSleep apnea-hypopnea quantification by cardiovascular data analysis(San Francisco, CA : Public Library of Science (PLoS), 2014) Camargo, S.; Riedl, M.; Anteneodo, C.; Kurths, J.; Penzel, T.; Wessel, N.Sleep disorders are a major risk factor for cardiovascular diseases. Sleep apnea is the most common sleep disturbance and its detection relies on a polysomnography, i.e., a combination of several medical examinations performed during a monitored sleep night. In order to detect occurrences of sleep apnea without the need of combined recordings, we focus our efforts on extracting a quantifier related to the events of sleep apnea from a cardiovascular time series, namely systolic blood pressure (SBP). Physiologic time series are generally highly nonstationary and entrap the application of conventional tools that require a stationary condition. In our study, data nonstationarities are uncovered by a segmentation procedure which splits the signal into stationary patches, providing local quantities such as mean and variance of the SBP signal in each stationary patch, as well as its duration L. We analysed the data of 26 apneic diagnosed individuals, divided into hypertensive and normotensive groups, and compared the results with those of a control group. From the segmentation procedure, we identified that the average duration 〈L〉, as well as the average variance 〈σ2〉, are correlated to the apnea-hypoapnea index (AHI), previously obtained by polysomnographic exams. Moreover, our results unveil an oscillatory pattern in apneic subjects, whose amplitude S∗ is also correlated with AHI. All these quantities allow to separate apneic individuals, with an accuracy of at least 79%. Therefore, they provide alternative criteria to detect sleep apnea based on a single time series, the systolic blood pressure.
- ItemThe role of risk communication in public health interventions. An analysis of risk communication for a community quarantine in Germany to curb the SARS-CoV-2 pandemic(San Francisco, California, US : PLOS, 2021) Scholz, Juliane; Wetzker, Wibke; Licht, Annika; Heintzmann, Rainer; Scherag, André; Weis, Sebastian; Pletz, Mathias; Betsch, Cornelia; Bauer, Michael; Dickmann, Petra; Frey, RosemaryBackground: Separating ill or possibly infectious people from their healthy community is one of the core principles of non-pharmaceutical interventions. However, there is scarce evidence on how to successfully implement quarantine orders. We investigated a community quarantine for an entire village in Germany (Neustadt am Rennsteig, March 2020) with the aim of better understanding the successful implementation of quarantine measures. Methods: This cross-sectional survey was conducted in Neustadt am Rennsteig six weeks after the end of a 14-day mandatory community quarantine. The sample size consisted of 562 adults (64% of the community), and the response rate was 295 adults, or 52% (33% of the community). Findings: National television was reported as the most important channel of information. Contact with local authorities was very limited, and partners or spouses played a more important role in sharing information. Generally, the self-reported information level was judged to be good (211/289 [73.0%]). The majority of participants (212/289 [73.4%]) approved of the quarantine, and the reported compliance was 217/289 (75.1%). A self-reported higher level of concern as well as a higher level of information correlated positively with both a greater acceptance of quarantine and self-reported compliant behaviour. Interpretation: The community quarantine presented a rare opportunity to investigate a public health intervention for an entire community. In order to improve the implementation of public health interventions, public health risk communication activities should be intensified to increase both the information level (potentially leading to better compliance with community quarantine) and the communication level (to facilitate rapport and trust between public health authorities and their communities). © 2021 Scholz et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
- ItemInsulin adsorption to catheter materials used for intensive insulin therapy in critically ill patients: Polyethylene versus polyurethane - possible cause of variation in glucose control?(Sharjah : Bentham Science Publishers B.V., 2014) Ley, S.C.; Ammann, J.; Herder, C.; Dickhaus, T.; Hartmann, M.; Kindgen-Milles, D.Introduction: Restoring and maintaining normoglycemia by intensified insulin therapy in critically ill patients is a matter of ongoing debate since the risk of hypoglycemia may outweigh positive effects on morbidity and mortality. In this context, adsorption of insulin to different catheter materials may contribute to instability of glucose control. We studied the adsorption of insulin to different tubing materials in vitro and the effects on glycemic control in vivo. Materials and Methods: In vitro experiments: A syringe pump was filled with 50 IU insulin diluted to 50 ml saline. A flow of 2 ml/h was perfused through polyethylene (PET) or polyurethane (PUR) tubing. Insulin concentrations were measured at the end of the tube for 24 hours using Bradford's protein assay. In vivo study: In a randomized double-blinded cross-over design, 10 intensive care patients received insulin via PET and PUR tubes for 24 hours each, targeting blood glucose levels of 80-150 mg/dl. We measured blood glucose levels, the insulin dose required to maintain target levels, and serum insulin and C-peptide levels. Results: In vitro experiments: After the start of the insulin infusion, only 20% (median, IQR 20-27) (PET) and 22% (IQR 16-27) (PUR) of the prepared insulin concentration were measured at the end of the 2 meter tubing. Using PET, after one hour infusion the concentration increased to 34% (IQR 29-36) and did not increase significantly during the next 24 hours (39% (IQR 39-40)). Using PUR, higher concentrations were detected than for PET at every measurement from 1 hour (82% (IQR 70-86)) to 24 hours (79% (IQR 64-87)). In vivo study: Glycemic control was effective and not different between groups. Significantly higher volumes of insulin solution had to be infused with PET compared to PUR (median PET 70.0 (IQR 56-82) ml vs. PUR 42 (IQR 31-63) ml; p=0.0015). Serum insulin concentrations did not decrease significantly one hour after changing to PET or PUR tubing. Conclusion: Polyurethane tubing systems allow application of insulin with significantly lower adsorption rates than polyethylene tubing systems. As a consequence, less insulin solution has to be infused to patients for effective blood glucose control. Tubing material of the insulin infusion may be crucial for safe and effective glycemic control in critically ill patients.
- ItemA new human adipocyte model with PTEN haploinsufficiency(Abingdon : Taylor and Francis Inc., 2020) Kässner F.; Kirstein A.; Händel N.; Schmid G.L.; Landgraf K.; Berthold A.; Tannert A.; Schaefer M.; Wabitsch M.; Kiess W.; Körner A.; Garten A.Few human cell strains are suitable and readily available as in vitro adipocyte models. We used resected lipoma tissue from a patient with germline phosphatase and tensin homolog (PTEN) haploinsufficiency to establish a preadipocyte cell strain termed LipPD1 and aimed to characterize cellular functions and signalling pathway alterations in comparison to the established adipocyte model Simpson-Golabi-Behmel-Syndrome (SGBS) and to primary stromal-vascular fraction cells. We found that both cellular life span and the capacity for adipocyte differentiation as well as adipocyte-specific functions were preserved in LipPD1 and comparable to SGBS adipocytes. Basal and growth factor-stimulated activation of the PI3 K/AKT signalling pathway was increased in LipPD1 preadipocytes, corresponding to reduced PTEN levels in comparison to SGBS cells. Altogether, LipPD1 cells are a novel primary cell model with a defined genetic lesion suitable for the study of adipocyte biology. © 2020, © 2020 The Author(s). Published by Informa UK Limited, trading as Taylor & Francis Group.