191 research outputs found

    Human umbilical cord cells for cardiovascular tissue engineering: a comparative study

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    Objective: Tissue engineering of viable, autologous cardiovascular replacements with the potential to grow, repair and remodel represents an attractive approach to overcome the shortcomings of available replacements for the repair of congenital cardiac defects. Currently, vascular myofibroblast cells represent an established cell source for cardiovascular tissue engineering. Cell isolation requires the invasive harvesting of venous or arterial vessel segments prior to scaffold seeding, a technique which may not be preferable, especially in pediatric patients. This study evaluates cells isolated from human umbilical cord artery, umbilical cord vein and whole cord as alternative autologous cell sources for cardiovascular tissue engineering. Methods: Cells were isolated from human umbilical cord artery (UCA), umbilical cord vein (UCV), whole umbilical cord (UCC) and saphenous vein segments (VC), and were expanded in culture. All three expanded cell groups were seeded on bioabsorbable copolymer strips and grown in vitro for 28 days. Isolated cells were characterized by flow cytometry, histology, immunohistochemistry, proliferation assays and compared to VC. Morphological analysis of the seeded polymer strips included histology, immunohistochemistry, sodium dodecyl sulfate-polyacrylamide gel electrophoresis, transmission electron microscopy (TEM), scanning electron microscopy (SEM) and uniaxial stress testing. Results: UCA, UCV and UCC demonstrated excellent cell growth properties comparable to VC. Following isolation, all three cell groups showed myofibroblast-like morphology and characteristics by staining positive for α-smooth muscle actin (ASMA) and vimentin. Histology and immunohistochemistry of seeded polymers showed good tissue and extracellular matrix formation containing collagen I, III and elastin. TEM showed viable myofibroblasts and the deposition of collagen fibrils and progessive growing tissue formation, with a confluent surface, was observed in SEM. No difference was found among the mechanical properties of UCA, UCV, UCC and VC tissue engineered constructs. Conclusions: Tissue engineering of cardiovascular constructs by using UCA, UCV and UCC is feasible in an in vitro environment. Cell growth, morphology, characteristics and tissue formation were comparable between UCA, UCV, UCC and VC. UCC represent an attractive, readily available autologous cell source for cardiovascular tissue engineering offering the additional benefits of utilizing juvenile cells and avoiding the invasive harvesting of intact vascular structure

    Effects of exercise in people with severe mental illness and recommendations for its implementation as add-on therapy [Abstract]

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    There are many reasons for people with (and without) severe mental illness to exercise regularly. In people with schizophrenia, major depression and bipolar disorder, it has already been shown that regular physical activity as an add-on therapy can improve quality of life and symptom severity. This is particularly important in domains that standard therapy is currently not able to treat sufficiently, such as cognitive deficits. Postulated underlying neurobiological effects include increased volume in hippocampal areas as demonstrated by data of a current clinical trial in people with schizophrenia. Furthermore, regular exercise is essential to counteract the increased cardiovascular morbidity and mortality of people with severe mental illness. However, most people with severe mental illness do not achieve the recommended amount of physical activity and the potential of exercise as an add-on therapy is currently not even close to being fully realized. On the one hand, it is important that mental health staff also considers the physical condition of patients with mental illnesses and counsels them on their health behavior. On the other hand, there is a need for individually adapted training programs delivered by qualified exercise professionals that incorporate motivational and adherence strategies. Examples of barriers and facilitators for the implementation of exercise as an add-on therapy are discussed on the basis of current local projects

    A new source for cardiovascular tissue engineering: human bone marrow stromal cells

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    Objective: Vascular-derived cells represent an established cell source for tissue engineering of cardiovascular constructs. Previously, cell isolation was performed by harvesting of vascular structures prior to scaffold seeding. Marrow stromal cells (MSC) demonstrate the ability to differentiate into multiple mesenchymal cell lineages and would offer an alternative cell source for tissue engineering involving a less invasive harvesting technique. We studied the feasibility of using MSC as an alternative cell source for cardiovascular tissue engineering. Methods: Human MSC were isolated from bone marrow and expanded in culture. Subsequently MSC were seeded on bioabsorbable polymers and grown in vitro. Cultivated cells and seeded polymers were studied for cell characterization and tissue formation including extracellular matrix production. Applied methods comprised flow cytometry, histology, immunohistochemistry, transmission (TEM) and scanning electron microscopy (SEM), and biochemical assays. Results: Isolated MSC demonstrated fibroblast-like morphology. Phenotype analysis revealed positive signals for alpha-smooth muscle actin and vimentin. Histology and SEM of seeded polymers showed layered tissue formation. TEM demonstrated formation of extracellular matrix with deposition of collagen fibrils. Matrix protein analysis showed production of collagen I and III. In comparison to vascular-derived cell constructs quantitative analysis demonstrated comparable amounts of extracellular matrix proteins in the tissue engineered constructs. Conclusions: Isolated MSC demonstrated myofibroblast-like characteristics. Tissue formation on bioabsorbable scaffolds was feasible with extracellular matrix production comparable to vascular-cell derived tissue engineered constructs. It appears that MSC represent a promising cell source for cardiovascular tissue engineerin

    Seasonal sub-basin-scale runoff predictions: A regional hydrometeorological Ensemble Kalman Filter framework using global datasets

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    Study region The São Francisco River Basin (SFRB) in Brazil Study focus In semi-arid regions, interannual variability of seasonal rainfall and climate change is expected to stress water availability and increase the recurrence and intensity of extreme events such as droughts or floods. Local decision makers therefore need reliable long-term hydro-meteorological forecasts to support the seasonal management of water resources, reservoir operations and agriculture. In this context, an Ensemble Kalman Filter framework is applied to predict sub-basin-scale runoff employing global freely available datasets of reanalysis precipitation (ERA5-Land) as well as bias-corrected and spatially disaggregated seasonal forecasts (SEAS5-BCSD). Runoff is estimated using least squares predictions, exploiting the covariance structures between runoff and precipitation. The performance of the assimilation framework was assessed using different ensemble skill scores. New hydrological insights for the region Our results show that the quality of runoff predictions are closely linked to the performance of the rainfall seasonal predictions and allows skillful predictions up to two months ahead in most sub-basins. The anthropogenic conditions such as in the Western Bahia state, however, must be taken under consideration, since non-stationary runoff time-series have poorer skill as such unnatural variations can not be captured by long-term covariances. In sub-basins which are dominated by little anthropogenic influence, the presented framework provides a promising and easily transferable approach for skillful operational seasonal runoff predictions on sub-basin scale

    Recommended motor assessments based on psychometric properties in individuals with dementia: A systematic review

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    Abstract Background Motor assessments are important to determine effectiveness of physical activity in individuals with dementia (IWD). However, inappropriate and non-standardised assessments without sound psychometric properties have been used. This systematic review aims to examine psychometric properties of motor assessments in IWD combined with frequency of use and effect sizes and to provide recommendations based on observed findings. We performed a two-stage systematic literature search using Pubmed, Web of Science, Cochrane Library, ALOIS, and Scopus (inception - July/September 2018, English and German). The first search purposed to identify motor assessments used in randomised controlled trials assessing effectiveness of physical activity in IWD and to display their frequency of use and effect sizes. The second search focused on psychometric properties considering influence of severity and aetiology of dementia and cueing on test-retest reliability. Two reviewers independently extracted and analysed findings of eligible studies in a narrative synthesis. Results Literature searches identified 46 randomised controlled trials and 21 psychometric property studies. While insufficient information was available for validity, we observed sufficient inter-rater and relative test-retest reliability but unacceptable absolute test-retest reliability for most assessments. Combining these findings with frequency of use and effect sizes, we recommend Functional Reach Test, Groningen Meander Walking Test (time), Berg Balance Scale, Performance Oriented Mobility Assessment, Timed Up & Go Test, instrumented gait analysis (spatiotemporal parameters), Sit-to-Stand assessments (repetitions> 1), and 6-min walk test. It is important to consider that severity and aetiology of dementia and cueing influenced test-retest reliability of some assessments. Conclusion This review establishes an important foundation for future investigations. Sufficient relative reliability supports the conclusiveness of recommended assessments at group level, while unacceptable absolute reliability advices caution in assessing intra-individual changes. Moreover, influences on test-retest reliability suggest tailoring assessments and instructions to IWD and applying cueing only where it is inevitable. Considering heterogeneity of included studies and insufficient examination in various areas, these recommendations are not comprehensive. Further research, especially on validity and influences on test-retest reliability, as well as standardisation and development of tailored assessments for IWD is crucial. This systematic review was registered in PROSPERO (CRD42018105399)

    On the morphology of ammonium nitrate (III): theory and observation

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    The aim of this paper is to derive on a theoretical basis the morphology of crystals of ammonium nitrate, phase III, and to compare the results with experimental growth forms. The theory used is based on the concepts of periodic bond chain (PBC), F face and connected net, developed by Hartman and Perdok. Further an Ising model is used to determine roughening temperatures. Based on different criteria theoretical growth forms are predicted and compared with experiments

    The Λp\bf{\Lambda p} interaction studied via femtoscopy in p + Nb reactions at sNN=3.18 GeV\mathbf{\sqrt{s_{NN}}=3.18} ~\mathrm{\bf{GeV}}

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    We report on the first measurement of pΛp\Lambda and pppp correlations via the femtoscopy method in p+Nb reactions at sNN=3.18 GeV\mathrm{\sqrt{s_{NN}}=3.18} ~\mathrm{GeV}, studied with the High Acceptance Di-Electron Spectrometer (HADES). By comparing the experimental correlation function to model calculations, a source size for pppp pairs of r0,pp=2.02±0.01(stat)−0.12+0.11(sys) fmr_{0,pp}=2.02 \pm 0.01(\mathrm{stat})^{+0.11}_{-0.12} (\mathrm{sys}) ~\mathrm{fm} and a slightly smaller value for pΛp\Lambda of r0,Λp=1.62±0.02(stat)−0.08+0.19(sys) fmr_{0,\Lambda p}=1.62 \pm 0.02(\mathrm{stat})^{+0.19}_{-0.08}(\mathrm{sys}) ~\mathrm{fm} is extracted. Using the geometrical extent of the particle emitting region, determined experimentally with pppp correlations as reference together with a source function from a transport model, it is possible to study different sets of scattering parameters. The pΛp\Lambda correlation is proven sensitive to predicted scattering length values from chiral effective field theory. We demonstrate that the femtoscopy technique can be used as valid alternative to the analysis of scattering data to study the hyperon-nucleon interaction.Comment: 12 pages, 11 figure
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