Salamanders and fish can regenerate lost structures - why can't we?

The recent introduction of in vivo lineage-tracing techniques using fluorescently labeled cells challenged the long-standing view that complete dedifferentiation is a major force driving vertebrate tissue regeneration. The report in BMC Developmental Biology by Juan Carlos Izpisúa Belmonte and colleagues adds a new twist to a rapidly evolving view of the origin of blastemal cells. As classic and recent experimental findings are considered together, a new perspective on vertebrate muscle regeneration is emerging

Biochemical and mechanical environment cooperatively regulate skeletal muscle regeneration

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/154392/1/fsb2026006030.pd

Putting Cells into Context

Opinion article (excerpt): Cells Live in a Complex World It may sound blatantly obvious, but we have to remind ourselves occasionally that in vivo cells experience an environment with a level of complexity far beyond experimental reach. The developing organism is a highly complex system, where each cell receives a multitude of cues of diverse nature at any given time point. Only the comprehensive integration of all these multivalent interactions determines the actual signaling state and hence the behavior of a cell. The analysis of biological questions is mainly inspired by a reductionist approach adopted from the “exact sciences,” where it has been proven immensely successful. That is, we are used to break down our experimental setup to a manageable number of variables. This of course is inherently contradictory to the complexity of biological systems. While simplification may be the only viable option for the experimenter to dissect biological function down to detail, it has also influenced our perspective toward the experimental systems applied. For example, studies of intracellular signaling pathways are typically performed with cultured cells. Culturing cells in an in vitro setting became a standard model system in biomedical research and with it in cell and developmental biology. These simplified systems allow for the dissection of molecular interactions and pathways and are aimed to deepen and mechanistically understand cellular behavior. While cell cultures have generated a wealth of information into cellular function, the data obtained in vitro frequently are in conflict with in vivo observations. One reason for this discrepancy is that these analyses focus on the cell as a closed functional system, thus conceptually unhinging it from its environment

A Modeling Approach for Blockchain-inspired Business Models: An Extension of the e3 -Value Method

Blockchain enables new ways of organizing economic activities. Blockchain promises to reduce costs and time associated with intermediaries and strengthen trust in an ecosystem of actors. The impact of this promising technology is reflected in an emerging stream of research and various companies exploring the potential uses of blockchain technology and building new blockchain-inspired business models. While there are promising use cases of this new technology, research and practice are still in their early stages in terms of changing existing and creating new business models. We propose an extension of the e3 -value method to capture and represent the characteristics of blockchain-inspired business models. The approach is particularly useful for the value-based analysis of blockchain-inspired business models and the fundamental economic evaluation of these. It provides the foundation for capturing, communicating, innovating and experimenting with blockchain-inspired business models. We demonstrate the practicality of the extended e3 -value method by evaluating and applying it to an existing blockchain business model

Methods for the evaluation of waste treatment processes

Decision makers for waste management are confronted with the problem of selecting the most economic, environmental, and socially acceptable waste treatment process. This paper elucidates evaluation methods for waste treatment processes for the comparison of ecological and economic aspects such as material flow analysis, statistical entropy analysis, energetic and exergetic assessment, cumulative energy demand, and life cycle assessment. The work is based on the VDI guideline 3925. A comparison of two thermal waste treatment plants with different process designs and energy recovery systems was performed with the described evaluation methods. The results are mainly influenced by the type of energy recovery, where the waste-to-energy plant providing district heat and process steam emerged to be beneficial in most aspects. Material recovery options from waste incineration were evaluated according to sustainability targets, such as saving of resources and environmental protection

Vegetation natürlicher Felsen und Felsköpfe sowie lückiger Pionierrasen

Felsen haben wegen ihrer besonderen landschaftsprägenden Bedeutung schon früh die Aufmerksamkeit des Menschen auf sich gezogen, und eine Fülle geschichtsträchtiger und kultureller Zentren des Menschen befinden sich bis heute an und um Felsen. Felsen sind aber auch Extremstandorte und die hier lebenden Tiere und Pflanzen vielfach hochangepaßte Spezialisten. Im Rahmen der Umsetzung der FFH-Richtlinie ihrer Bedeutung als Lebensraum vieler seltener und zum Teil bedrohter Arten Rechnung getragen. Im Folgenden werden neben typischen Farn- und Blütenpflanzen auch einige Moose und Flechten vorgestellt. Da die meisten Moos- und Flechtenarten keine deutschen Namen tragen, werden die botanischen Namen verwendet

Stand-alone percutaneous stent-kyphoplasty for thoracolumbar split and burst-split fractures

Introduction Traditionally, thoracolumbar split and burst-split fractures are treated with combined antero-posterior bi-segmental fusion procedures. Especially in the lower lumbar spine, such interventions are invasive and are associated with increased risk of neurological and vascular complications. This retrospective study aims to determine whether percutaneous stent-kyphoplasty is a viable treatment option for these injuries in terms of kyphotic angle correction and patient safety. Methods From Nov. 2014 to Dec. 2017, 25 consecutive patients (9 female, mean age 58 years) with 8 thoracolumbar split and 17 burst-split fractures (T11 to L5) of different etiology (7 high vs. 18 low energy trauma) were treated with percutaneous stent-kyphoplasty (SpineJack®). CT and/or MR imaging was performed preoperatively in all patients while radiographs were obtained postoperatively and at each follow-up. The mean follow-up was 176 days (SD 130). All cases were evaluated retrospectively for complications regarding nervous damage, LOS, duration of opioid intake, pain-VAS, return to work time and change of radiographic kyphotic angle. Results The mean kyphotic angle did not change from 1.1° (SD 9.2°) preoperatively to 1.1° (SD 7.9°) postoperatively. Radiologically, the mean increase of the kyphotic angle between surgery and the last follow-up was 2.65° (SD 4.2°). The mean pain-VAS was reduced to 1.8 postoperatively (SD 2.5, p = 0.03). The mean opioid intake duration was 4 days. Conclusion SpineJack®-kyphoplasty appears to be a safe and expeditious, minimally invasive treatment option for thoracolumbar split or burst-split fractures. It may be considered as an alternative to combined anterior-posterior instrumented bi-segmental fusion with its associated surgical morbidity

Quality of reduction correlates with clinical outcome in pelvic ring fractures

INTRODUCTION Posttraumatic pelvic deformity is associated with pain and loss of function. This study aimed to test the correlation of functional outcome in patients with pelvic fractures with the postoperative radiographic quality of reduction. METHODS Consecutive patients with an isolated traumatic pelvic fracture that required closed or open reduction between 07/2015 and 07/2017 and had a completed follow-up of at least 6 months were included (N = 31, mean age 50 years, SD 21 years, range, 16 to 88 years). Majeed and Timed Up & Go were obtained from a prospective outcome database at 6 months and last follow-up (mean 10 months, SD 5 months). Quality of pelvic ring reduction was determined on postoperative radiographs as described by Matta, Sagi and Keshishyan/Lefaivre. RESULTS Clinical outcome at 6 months as measured by the Majeed and the Timed Up & Go correlated moderately with Keshishyan/Lefaivre's pelvic asymmetry value (Pearson R: -0.520 and 0.585, p ≤ 0.003) and the pelvic deformity index (-0.527 and 0.503, p ≤ 0.004). There was a weak correlation between the Timed Up & Go and the radiographic grading system as described by Matta/Tournetta at 6 months (0.408, p = 0.023) and at last follow-up (0.380, p = 0.035). CONCLUSIONS This study showed a moderate correlation of the clinical outcome at 6 months with postoperative quality of radiographic reduction when measured with the method described by Keshishyan and Lefaivre. Although having only descriptive value due to the small cohort, our findings underline the importance of anatomic reduction and restoration of pelvic symmetry in patients with pelvic trauma. Future studies with more patients and more investigators are required and reliability and validity of functional outcome scores needs to be further assessed to predict outcome in patient with fractures of the pelvic ring. LEVEL OF EVIDENCE Level IV (case series)

Pdlim7 is required for maintenance of the mesenchymal/epidermal Fgf signaling feedback loop during zebrafish pectoral fin development

<p>Abstract</p> <p>Background</p> <p>Vertebrate limb development involves a reciprocal feedback loop between limb mesenchyme and the overlying apical ectodermal ridge (AER). Several gene pathways participate in this feedback loop, including Fgf signaling. In the forelimb lateral plate mesenchyme, Tbx5 activates Fgf10 expression, which in turn initiates and maintains the mesenchyme/AER Fgf signaling loop. Recent findings have revealed that Tbx5 transcriptional activity is regulated by dynamic nucleocytoplasmic shuttling and interaction with Pdlim7, a PDZ-LIM protein family member, along actin filaments. This Tbx5 regulation is critical in heart formation, but the coexpression of both proteins in other developing tissues suggests a broader functional role.</p> <p>Results</p> <p>Knock-down of Pdlim7 function leads to decreased pectoral fin cell proliferation resulting in a severely stunted fin phenotype. While early gene induction and patterning in the presumptive fin field appear normal, the pectoral fin precursor cells display compaction and migration defects between 18 and 24 hours post-fertilization (hpf). During fin growth <it>fgf24 </it>is sequentially expressed in the mesenchyme and then in the apical ectodermal ridge (AER). However, in <it>pdlim7 </it>antisense morpholino-treated embryos this switch of expression is prevented and <it>fgf24 </it>remains ectopically active in the mesenchymal cells. Along with the lack of <it>fgf24 </it>in the AER, other critical factors including <it>fgf8 </it>are reduced, suggesting signaling problems to the underlying mesenchyme. As a consequence of perturbed AER function in the absence of Pdlim7, pathway components in the fin mesenchyme are misregulated or absent, indicating a breakdown of the Fgf signaling feedback loop, which is ultimately responsible for the loss of fin outgrowth.</p> <p>Conclusion</p> <p>This work provides the first evidence for the involvement of Pdlim7 in pectoral fin development. Proper fin outgrowth requires <it>fgf24 </it>downregulation in the fin mesenchyme with subsequent activation in the AER, and Pdlim7 appears to regulate this transition, potentially through Tbx5 regulation. By controlling Tbx5 subcellular localization and transcriptional activity and possibly additional yet unknown means, Pdlim7 is required for proper development of the heart and the fins. These new regulatory mechanisms may have important implications how we interpret Tbx5 function in congenital hand/heart syndromes in humans.</p