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The Spontaneous Induction of Bone Formation by Intrinsically Osteoinductive Bioreactors for Human Patients
Published in Ugo Ripamonti, The Geometric Induction of Bone Formation, 2020
Studying myosin-mediated morphogenesis in choanoflagellates and animals, Brunet et al. report in Science the evolutionary history of tissue bending (Tomancak 2019), and that newly discovered unicellular eukaryotes show hallmark features of animal morphogenesis (Brunet et al. 2019; Tomancak 2019). Inverting sheets of connected cells, because of actomyosin activity triggered by darkness or light, results in a change of morphology, i.e. opening of collar microvilli and sheet inversion as well as behaviour, from feeding to swimming (Brunet et al. 2019; Tomancak 2019). In animal embryos, local myosin-induced apical construction or tissue bending leads to epithelia tissue invagination during gastrulation (Brunet et al. 2019). Highly conserved myosin protein sequences do exist between choanoflagellates and animals; the inversion behaviour of choanoflagellates “uses the same actomyosin molecular machinery deployed by animal cells to sculpt tissue during development through apical constriction or tissue bending” (Tomancak 2019).
Embryology of malformations
Published in Prem Puri, Newborn Surgery, 2017
Dietrich Kluth, Wolfgang Lambrecht, Christoph Bührer, Roman Metzger
Cell shape is mainly maintained by microtubules forming the cellular cytoskeleton. In addition, contractile elements exist such as actin, which are essential for cell movement, the so-called microfilaments. These structures are thought to be essential for the process of placode formation and invagination.67 Microfilament-mediated change of cell shape is based on the idea that actin filaments could alter the shape of cells by contraction. Most of these filaments are found at the apex of epithelial cells. Contraction of these filaments in each individual cell of a cell layer would result in an increasing infolding of the whole cell layer,67,68 finally resulting in invagination. It is a disadvantage of this model, however, that there is no apparent reason why apical constriction should proceed by cell elongation.55
Molecular biology of irreversible pulpitis: A case report
Published in Robert Hofstra, Noriyuki Koibuchi, Suthat Fucharoen, Advances in Biomolecular Medicine, 2017
In this case study, root canal preparation is done with the crown down technique because it can remove more debris and microorganisms toward the coronal and maintain apical constriction, which can prevent the debris from being pushed to the apical region. The irrigating solution used is 2.5% NaOCl because it has an anti-microbial effect and can break the chains of proteins and damage bacterial DNA synthesis activity, as well as enhance lubrication. The use of 15% EDTA solution is effective in eliminating the smear layer, particularly inorganic components.11,12
MRCK: a master regulator of tissue remodeling or another ‘ROCK’ in the epithelial block?
Published in Tissue Barriers, 2021
Apical constriction, an opposing process to apical expansion, describes a shrinking of the apical cell surface and is an important morphogenic event during developmental processes such as neural tube formation in vertebrates and gastrulation in many systems.35 Apical constriction involves medio-apical actomyosin networks, positioned at the apical cortex, under tension that generate force36–38 and perijunctional actomyosin belts that contract via a purse-string mechanism.39,40 Since medio-apical networks are connected to junctions a fundamental question has persisted, as to how these two structures are maintained, coupled, and coordinated spatially and temporally.
The value of assessing case difficulty and its effect on endodontic iatrogenic errors: a retrospective cross-sectional study
Published in Libyan Journal of Medicine, 2020
Ruaa A. Alamoudi, Afrah H. Alharbi, Ghada A. Farie, Omar Fahim
Overfilling was detected in 4% of all cases treated in undergraduate dental clinics. This may be attributable to inadequate length determination or over-instrumentation. Molars have the shortest roots compared to other teeth, which makes them more susceptible to this type of error [23]. Over-instrumentation damages the apical constriction, which makes it difficult to obtain an adequate apical seal and confine obturation materials within the root canal system. Over-instrumentation in the undergraduate clinic may be attributable to the lack of attention to reference points.