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- Krivanek, J, et al.
(författare)
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Dental cell type atlas reveals stem and differentiated cell types in mouse and human teeth
- 2020
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Ingår i: Nature communications. - : Springer Science and Business Media LLC. - 2041-1723. ; 11:1, s. 4816-
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Tidskriftsartikel (refereegranskat)abstract
- Understanding cell types and mechanisms of dental growth is essential for reconstruction and engineering of teeth. Therefore, we investigated cellular composition of growing and non-growing mouse and human teeth. As a result, we report an unappreciated cellular complexity of the continuously-growing mouse incisor, which suggests a coherent model of cell dynamics enabling unarrested growth. This model relies on spatially-restricted stem, progenitor and differentiated populations in the epithelial and mesenchymal compartments underlying the coordinated expansion of two major branches of pulpal cells and diverse epithelial subtypes. Further comparisons of human and mouse teeth yield both parallelisms and differences in tissue heterogeneity and highlight the specifics behind growing and non-growing modes. Despite being similar at a coarse level, mouse and human teeth reveal molecular differences and species-specific cell subtypes suggesting possible evolutionary divergence. Overall, here we provide an atlas of human and mouse teeth with a focus on growth and differentiation.
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- Krivanek, J, et al.
(författare)
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Plasticity of Dental Cell Types in Development, Regeneration, and Evolution
- 2023
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Ingår i: Journal of dental research. - : SAGE Publications. - 1544-0591 .- 0022-0345. ; 102:6, s. 589-598
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Tidskriftsartikel (refereegranskat)abstract
- Recent years have improved our understanding of the plasticity of cell types behind inducing, building, and maintaining different types of teeth. The latest efforts were aided by progress in single-cell transcriptomics, which helped to define not only cell states with mathematical precision but also transitions between them. This includes new aspects of dental epithelial and mesenchymal stem cell niches and beyond. These recent efforts revealed continuous and fluid trajectories connecting cell states during dental development and exposed the natural plasticity of tooth-building progenitors. Such “developmental” plasticity seems to be employed for organizing stem cell niches in adult continuously growing teeth. Furthermore, transitions between mature cell types elicited by trauma might represent a replay of embryonic continuous cell states. Alternatively, they could constitute transitions that evolved de novo, not known from the developmental paradigm. In this review, we discuss and exemplify how dental cell types exhibit plasticity during dynamic processes such as development, self-renewal, repair, and dental replacement. Hypothetically, minor plasticity of cell phenotypes and greater plasticity of transitions between cell subtypes might provide a better response to lifetime challenges, such as damage or dental loss. This plasticity might be additionally harnessed by the evolutionary process during the elaboration of dental cell subtypes in different animal lineages. In turn, the diversification of cell subtypes building teeth brings a diversity of their shape, structural properties, and functions.
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- Krivanek, Ondrej L., et al.
(författare)
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Toward Single Mode, Atomic Size Electron Vortex Beams
- 2014
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Ingår i: Microscopy and Microanalysis. - 1431-9276 .- 1435-8115. ; 20:3, s. 832-836
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Tidskriftsartikel (refereegranskat)abstract
- We propose a practical method of producing a single mode electron vortex beam suitable for use in a scanning transmission electron microscope (STEM). The method involves using a holographic "fork" aperture to produce a row of beams of different orbital angular momenta, as is now well established, magnifying the row so that neighboring beams are separated by about 1 mu m, selecting the desired beam with a narrow slit, and demagnifying the selected beam down to 1-2 angstrom in size. We show that the method can be implemented by adding two condenser lenses plus a selection slit to a straight-column cold-field emission STEM. It can also be carried out in an existing instrument, the monochromated Nion high-energy-resolution monochromated electron energy-loss spectroscopy-STEM, by using its monochromator in a novel way. We estimate that atom-sized vortex beams with <= 20 pA of current should be attainable at 100-200 keV in either instrument.
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- Shahidi, MK, et al.
(författare)
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Three-dimensional Imaging Reveals New Compartments and Structural Adaptations in Odontoblasts
- 2015
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Ingår i: Journal of dental research. - : SAGE Publications. - 1544-0591 .- 0022-0345. ; 94:7, s. 945-954
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Tidskriftsartikel (refereegranskat)abstract
- In organized tissues, the precise geometry and the overall shape are critical for the specialized functions that the cells carry out. Odontoblasts are major matrix-producing cells of the tooth and have also been suggested to participate in sensory transmission. However, refined morphologic data on these important cells are limited, which hampers the analysis and understanding of their cellular functions. We took advantage of fluorescent color-coding genetic tracing to visualize and reconstruct in 3 dimensions single odontoblasts, pulp cells, and their assemblages. Our results show distinct structural features and compartments of odontoblasts at different stages of maturation, with regard to overall cellular shape, formation of the main process, orientation, and matrix deposition. We demonstrate previously unanticipated contacts between the processes of pulp cells and odontoblasts. All reported data are related to mouse incisor tooth. We also show that odontoblasts express TRPM5 and Piezo2 ion channels. Piezo2 is expressed ubiquitously, while TRPM5 is asymmetrically distributed with distinct localization to regions proximal to and within odontoblast processes.
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