Publications by authors named "Helmholz H"

Osteoarthritis (OA) is a significant condition that profoundly impacts synovial joints, including cartilage and subchondral bone plate. Biomaterials that can impede OA progression are a promising alternative or supplement to anti-inflammatory and surgical interventions. Magnesium (Mg) alloys known for bone regeneration potential were assessed in the form of Mg microparticles regarding their impact on tissue regeneration and prevention of OA progression.

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  • - Mg-Li alloys may serve as effective bioresorbable implants that release lithium (Li) for treating bipolar and neurodegenerative disorders, potentially offering advantages over traditional Li salts.
  • - In a study utilizing a neuroinflammation model, two Mg-Li alloys (Mg-1.6Li and Mg-9.5Li) were tested, showing that Li from these alloys enhanced the phosphorylation of GSK3β in glial cells more effectively than Li salts.
  • - The results indicate that Mg-Li alloys can improve the modulation of inflammation-related gene expression and support further exploration of their therapeutic potential in neurological treatments.
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  • Magnesium (Mg) alloys, particularly those with gadolinium, are emerging as promising materials for temporary bone implants due to their biocompatibility and mechanical properties, presenting a potential replacement for traditional titanium and stainless-steel implants.
  • A study involving rat tibias over various time periods (10, 20, and 32 weeks) used advanced imaging techniques to evaluate the implants' degradation behavior and their integration with bone tissues.
  • Results indicate that the Mg-xGd implants not only form a stable degradation layer and support bone remodeling similar to titanium but also do not accumulate harmful levels of Mg or Gd in organs, making them suitable for use in bone repair.
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In this study, the interaction of pure Mg and WE43 alloy under the presence of osteoblast (OB) and osteoclast (OC) cells and their influence on the degradation of materials have been deeply analyzed. Since OB and OC interaction has an important role in bone remodeling, we examined the surface morphology and dynamic changes in the chemical composition and thickness of the corrosion layers formed on pure Mg and WE43 alloy by direct monoculture and coculture of pre-differentiated OB and OC cells in vitro. Electrochemical techniques examined the corrosion performance.

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With its main features of cartilage degeneration, subchondral bone sclerosis and osteophyte formation, osteoarthritis represents a multifactorial disease with no effective treatment options. As biomechanical shift in the trabecular network may be a driver for further cartilage degeneration, bone enhancement could possibly delay OA progression. Magnesium is known to be osteoconductive and already showed positive effects in OA models.

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The immune system plays an important role in fracture healing, by modulating the pro-inflammatory and anti-inflammatory responses occurring instantly upon injury. An imbalance in these responses can lead to adverse outcomes, such as non-union of fractures. Implants are used to support and stabilize complex fractures.

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  • Magnesium-based implants are gaining popularity in orthopedic applications due to their ability to degrade and release bioactive Mg ions that influence mesenchymal stem cells (MSCs), which are crucial for bone regeneration.
  • The study utilized gene regulatory network analysis with time-series proteomics data to explore how MSCs respond to Mg ions over a 21-day period.
  • Key proteins and interactions were identified, including MYL1, MDH2, GLS, and TRIM28, which play significant roles in MSCs' molecular response to Mg ions, paving the way for advancements in orthopedic biomaterials.
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  • * Exposing SCs to freeze-killed cell extracts (FKC) and nerve extracts (FKN) stimulated the release of MCP-1, a marker indicating SCs are responding to injury. However, adding Mg/Mg-1.6Li reduced MCP-1 release by 30%, suggesting potential anti-inflammatory properties.
  • * Depending on the microenvironment, Mg/Mg-1.6Li treatment led to different gene expression changes in SCs, enhancing factors beneficial for nerve regeneration when FKC was
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Lithium (Li), a widely used drug for bipolar disorder management, is associated with many side effects due to systemic exposure. The localized delivery of lithium through implants could be an approach to overcome this challenge, for which biodegradable magnesium (Mg)-based materials are a promising choice. In this study, we focus on Mg-Li thin film alloys as potential Li-releasing implants.

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Semisolid powder molding was used to prepare the medical Mg-6Zn alloy; in order to further improve its degradation adaptability, 0.5 and 1 wt % Mn were added. Then, the effect of the forming temperature (540, 560, 580, and 600 °C) on the degradation behavior of the prepared Mg-6Zn-Mn ( = 0.

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We propose a computational framework to study the effect of corrosion on the mechanical strength of magnesium (Mg) samples. Our work is motivated by the need to predict the residual strength of biomedical Mg implants after a given period of degradation in a physiological environment. To model corrosion, a mass-diffusion type model is used that accounts for localised corrosion using Weibull statistics.

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Magnesium (Mg) alloys have become a potential material for orthopedic implants due to their unnecessary implant removal, biocompatibility, and mechanical integrity until fracture healing. This study examined the and degradation of an Mg fixation screw composed of Mg-0.45Zn-0.

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New methodologies capable of extensively analyzing the cell-material interactions are necessary to improve current in vitro characterization methods, and proteomics is a viable alternative. Also, many studies are focused on monocultures, even though co-cultures model better the natural tissue. For instance, human mesenchymal stem cells (MSCs) modulate immune responses and promote bone repair through interaction with other cell types.

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Novel biodegradable metal alloys are increasingly used as implant materials. The implantation can be accompanied by an inflammatory response to a foreign object. For studying inflammation in the implantation area, non-invasive imaging methods are needed.

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Histochemical staining of paraffin-embedded decalcified bone samples is commonly used in preclinical research of musculoskeletal diseases, enabling the visualization of multiple tissue components by the application of chromogens. The purpose of this study was to introduce a novel multicolor staining protocol involving optimized chemical reagents and procedure, allowing the identification of high-mineralized bone, low-mineralized fracture callus, cartilage and skeletal muscle fibers simultaneously. Fractured femur and healthy tail vertebra samples from adult male Sprague-Dawley rats were decalcified with EDTA and formic acid, respectively, followed by paraffin embedding, tissue sectioning and multicolor staining.

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Though surgical techniques profoundly influence in vivo experiments, significant heterogeneity exists in current surgeries for inducing rat femoral bone defects. Such variations reduce the reproducibility and comparability of preclinical studies, and are detrimental to clinical translation. The purposes of this study were: (1) to conduct a systematic review of rat femoral defect models, summarizing and analyzing the surgical techniques; (2) to analyze surgical design and potential pitfalls via 3D anatomy and virtual surgeries for fostering future precision research; and (3) to establish a surgical classification system, for improving the reproducibility and comparability among studies, avoiding unnecessary repetitive experiments.

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In vitro triple cultures of human primary osteoblasts, osteocytes and osteoclasts can potentially help to analyze the effect of drugs and degradation products of biomaterials as a model for native bone tissue. In the present study, degradation products of Magnesium (Mg), which has been successfully applied in the biomedical field, were studied with respect to their impact on bone cell morphology and differentiation both in osteocyte single cultures and in the triple culture model. Fluorescence microscopic and gene expression analysis, analysis of osteoclast- and osteoblast-specific enzyme activities as well as osteocalcin protein expression were performed separately for the three cell types after cultivation in triple culture in the presence of extracts, containing 5 and 10 mM Mg.

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Rodent models are commonly used in pre-clinical research of magnesium (Mg)-based and other types of biomaterials for fracture treatment. Most studies selected unstable fixation methods, and there is a lack of multimodal longitudinal monitoring of bone healing. The purpose of this study is to develop a rat femoral fracture model stabilized by external fixation with intra-medullary Mg implant, and to investigate the dynamic bone union process with several imaging techniques offering complementing insights into the process.

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Extensive research is being conducted on magnesium (Mg) alloys for bone implant manufacturing, due to their biocompatibility, biodegradability and mechanical properties. Gadolinium (Gd) is among the most promising alloying elements for property control in Mg alloy implants; however, its toxicity is controversial. Investigating Gd behavior during implant corrosion is thus of utmost importance.

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No optimal therapy exists to stop or cure chondral degeneration in osteoarthritis (OA). While the pathogenesis is unclear, there is consensus on the etiological involvement of both articular cartilage and subchondral bone. Compared to original bone, the substance of sclerotic bone is mechanically less solid.

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Mesenchymal stem cells (MSCs) are proliferative and multipotent cells that play a key role in the bone regeneration process. Empirical data have repeatedly shown the bioregulatory importance of magnesium (Mg) ions in MSC growth and osteogenesis. In this study, we propose an agent-based model to predict the spatiotemporal dynamics of the MSC population and osteogenic differentiation in response to Mg ions.

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Biomedical applications of magnesium (Mg) and its alloys are generally dependent on their degradation behavior in vivo. Despite its attractive properties, which make Mg suitable for orthopedic applications, the in vivo material-tissue (bone, blood, and lymph tissues) interaction is not yet fully understood. To investigate the influence of major serum proteins on the degradation, this study focused on fetuin, which is one of the major non-collagenous plasma proteins and which is essential for biomineralization.

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We present a method for computing a spherical harmonic representation of a sound field based on observations of the sound pressure along the equator of a rigid spherical scatterer. Our proposed solution assumes that the captured sound field is height invariant so that it can be represented by a two-dimensional (2D) plane wave decomposition (PWD). The 2D PWD is embedded in a three-dimensional representation of the sound field, which allows for perfectly undoing the effect of the spherical scattering object.

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The local response of tissue triggered by implantation of degradable magnesium-based implant materials was investigated in vivo in a murine model. Pins (5.0 mm length by 0.

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Human mesenchymal stem cells (MSC) interact with numerous immune cells that can promote regenerative processes and inhibit inflammatory responses. We hypothesised that the cross-talk between human umbilical cord perivascular cells (HUCPV; an alternative source of MSC) and peripheral blood mononuclear cells (PBMC) could be influenced by degradable transwell magnesium (Mg). To study the correlations between paracrine signaling and specific cellular behaviour during the host response to Mg, we used a transwell coculture system for up to 7 days.

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