Extracellular matrix dynamics in cell migration, invasion and tissue morphogenesis.

This review describes how direct visualization of the dynamic interactions of cells with different extracellular matrix microenvironments can provide novel insights into complex biological processes. Recent studies have moved characterization of cell migration and invasion from classical 2D culture systems into 1D and 3D model systems, revealing multiple differences in mechanisms of cell adhesion, migration and signalling-even though cells in 3D can still display prominent focal adhesions. Myosin II restrains cell migration speed in 2D culture but is often essential for effective 3D migration. 3D cell migration modes can switch between lamellipodial, lobopodial and/or amoeboid depending on the local matrix environment. For example, "nuclear piston" migration can be switched off by local proteolysis, and proteolytic invadopodia can be induced by a high density of fibrillar matrix. Particularly, complex remodelling of both extracellular matrix and tissues occurs during morphogenesis. Extracellular matrix supports self-assembly of embryonic tissues, but it must also be locally actively remodelled. For example, surprisingly focal remodelling of the basement membrane occurs during branching morphogenesis-numerous tiny perforations generated by proteolysis and actomyosin contractility produce a microscopically porous, flexible basement membrane meshwork for tissue expansion. Cells extend highly active blebs or protrusions towards the surrounding mesenchyme through these perforations. Concurrently, the entire basement membrane undergoes translocation in a direction opposite to bud expansion. Underlying this slowly moving 2D basement membrane translocation are highly dynamic individual cell movements. We conclude this review by describing a variety of exciting research opportunities for discovering novel insights into cell-matrix interactions.

Preparation of Cells from Embryonic Organs for Single-Cell RNA Sequencing.

Although single-cell RNA sequencing (scRNA-seq) has become one of the most powerful methods available for transcriptome analysis, the quality of scRNA-seq data largely depends on cell preparation. Cell preparation from cultured cells and tissues requires different methods because of the inherent differences between these two categories of cells. Compared to cultured cells, tissues have more extracellular matrix, and the cells are generally more adherent and thus difficult to dissociate. The challenge is to achieve sufficient dissociation, cell counts, and viability all at the same time. This protocol describes approaches that help achieve these goals. These include a cold dissociation technique using cryophilic proteases active at cold temperature, timing of trituration during protease digestion, as well as filtration and washing methods that optimize cell viability and retention. Materials and equipment that optimize the process also discussed. © 2019 by John Wiley & Sons, Inc.

Basement Membranes in Development and Disease.

The basement membrane is a thin but dense, sheet-like specialized type of extracellular matrix that has remarkably diverse functions tailored to individual tissues and organs. Tightly controlled spatial and temporal changes in its composition and structure contribute to the diversity of basement membrane functions. These different basement membranes undergo dynamic transformations throughout animal life, most notably during development. Numerous developmental mechanisms are regulated or mediated by basement membranes, often by a combination of molecular and mechanical processes. A particularly important process involves cell transmigration through a basement membrane because of its link to cell invasion in disease. While developmental and disease processes share some similarities, what clearly distinguishes the two is dysregulation of cells and extracellular matrices in disease. With its relevance to many developmental and disease processes, the basement membrane is a vitally important area of research that may provide novel insights into biological mechanisms and development of innovative therapeutic approaches. Here we present a review of developmental and disease dynamics of basement membranes in Caenorhabditis elegans, Drosophila, and vertebrates.

Patterned cell and matrix dynamics in branching morphogenesis.

Many embryonic organs undergo branching morphogenesis to maximize their functional epithelial surface area. Branching morphogenesis requires the coordinated interplay of multiple types of cells with the extracellular matrix (ECM). During branching morphogenesis, new branches form by "budding" or "clefting." Cell migration, proliferation, rearrangement, deformation, and ECM dynamics have varied roles in driving budding versus clefting in different organs. Elongation of the newly formed branch and final maturation of the tip involve cellular mechanisms that include cell elongation, intercalation, convergent extension, proliferation, and differentiation. New methodologies such as high-resolution live imaging, tension sensors, and force-mapping techniques are providing exciting new opportunities for future research into branching morphogenesis.

Palatal mucosal measurements in a Japanese population using cone-beam computed tomography.

STATEMENT OF THE PROBLEM: Although assessment of entire palatal mucosal thickness is important in many dental procedures, available data are mostly limited to the lateral aspect of the palate. PURPOSE OF THE STUDY: The objective of this study was to use cone-beam computed tomography (CBCT) to perform a comprehensive analysis of the palatal mucosal thickness from the gingival margin to the mid-palatine suture in a Japanese population. Associations of palatal mucosal thickness with the palatal vault depth were also examined. METHODS/MATERIALS: Measurements on the coronal plane were obtained from 44 adults with 3-mm interval in the canine (Ca), first premolar (P1), second premolar (P2), midpoint between first and second molars (M1d), first molar (M1), and second molar (M2). Furthermore, the location of greater palatine foramen (GPF) and palatine groove (PG) were also investigated. RESULTS: Canine region did not show a significant difference throughout measured points. P1, P2, and all molar regions were thickest at 9, 12, and 12 mm from the gingival margin, respectively. At 3 and 6 mm, Ca, P1, and P2 showed significantly greater thickness than the molar region. At 9 mm, P1 demonstrated a greater thickness than M1d, and P2 was greater than M1 and Mi. At 12 and 15 mm, P1 was thinner than P2, M1, and M2, whereas P2 was thinner than M2. M1 was thinner than M2. The high-vault group showed a significantly greater thickness than the low-vault group. In majority of subjects, GPF and PG were identified in second molar and first premolar to first molar, respectively. CONCLUSION: Palatal mucosa in a Japanese population was the thickest in canine to premolar regions at 9 to 12 mm from the gingival margin. Identification of GPF and PG using CBCT can assist diagnosis of palate seems to minimize surgical complications. CLINICAL SIGNIFICANCE: This study evaluated the thickness of palatal mucosa in a Japanese population using cone-beam computed tomography, covering a wide range. Canine to second premolar regions are the most suitable in harvesting palatal mucosa for the purpose of soft tissue grafts.

Lightweight acrylic resin facial prosthesis for maxillofacial defects: a fabrication and retention method.

Extraoral maxillofacial rehabilitation for compromised or lost facial anatomy resulting from the surgical eradication of malignancy, trauma, or congenital anomalies is commonly accomplished with a silicone prosthesis. However, with increasing size and weight, a silicone prosthesis can lose retention. This report presents 2 patient treatments to introduce a fabrication and retention method for a lightweight acrylic resin facial prosthesis. The prosthesis was fabricated by bonding an acrylic resin facial shell to a computer-edited facial image printed with iron-on transfers. The completed prosthesis was attached to the skin with medical-grade double-sided adhesive tape, which maintained a tight marginal seal even when in contact with saliva and water. The strong prosthetic retention of the lightweight prosthesis enabled orofacial and speech rehabilitation, which makes it a promising alternative to the conventional silicone prosthesis, especially for the restoration of extensive maxillofacial defects.

Effects of implant surgery on blood pressure and heart rate during sedation with propofol and midazolam.

PURPOSE: Intravenous (IV) sedation is commonly used in dentistry. However, no report has yet been published regarding age, hypertension, and antihypertensive drugs during implant surgery and their relationship with changes in blood pressure (BP) and heart rate in implant surgery under IV sedation with propofol and midazolam. MATERIALS AND METHODS: Medical records of 252 patients who underwent implant surgery were retrospectively analyzed. Patients were classified into four groups according to their age (in years) and hypertension status: A=≤64, no hypertension; B=≥65, no hypertension; C=≤64, hypertension; or D=≥65, hypertension. Hypertensive patients were further characterized by their antihypertensive medications: E=calcium channel blockers (CCBs), F=angiotensin II receptor blockers (ARBs), G=CCBs+ARBs, or H=no medication. IV sedation was administered in two stages. After midazolam injection to prevent angialgia, propofol was infused at the rate of 4 mg/kg/h, followed by a dose reduction. Systolic and diastolic BP and heart rate were recorded before, during, and after surgery. RESULTS: Systolic BP increased significantly after patients were draped in groups A, C, and D, with group D showing the most pronounced increase. Sedatives decreased BP in all groups. Diastolic BP in group F decreased significantly compared to group H after induction and before infiltration of local anesthetic. After infiltration, systolic BP decreased more significantly in group G than in group H. Intraoperative hypotension was observed in 25% of patients. The incidence of intraoperative hypertension in group D was markedly higher than in group A (23% vs 4%). CONCLUSION: IV sedation using midazolam and propofol reduces hypertensive risks during implant surgery. Nevertheless, care must be taken, especially in older hypertensive patients and in hypertensive patients on ARBs or ARBs+CCBs.