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Approaches to Studying Polycystic Kidney Disease in Zebrafish
Published in Jinghua Hu, Yong Yu, Polycystic Kidney Disease, 2019
ProcedureArray embryos into 12-well plates with 25 embryos per well. 12-well plates are chosen here as the embryos are from heterozygous cross and only 25% embryos are expected as homozygous mutants. For treating wildtype embryos with chemicals, use 96-well plate and 3 embryos per well instead.At 50% epiboly stage, chemicals were added at a starting concentration of 10 × IC50 or 10 μM with 1% DMSO. Use embryos in 1% DMSO as a control at each time.Analyze phenotypes, including left-right asymmetry; body curvature; and cystic kidney at 30 hpf, 2, 3, and 5 dpf, respectively. Left-right asymmetry was determined by examining the heart position in the embryos at 30 hpf.Take images.(Optional) Titrate: If the chemical causes severe abnormality or lethality in the embryo, decrease the concentration by 5–10 fold. On the contrary, if the chemical barely affects the embryonic development, increase the concentration by 5–10 fold.
The embryonic period
Published in Frank J. Dye, Human Life Before Birth, 2019
Gastrulation and neurulation occur during the early embryonic period. Both of these processes involve cell movements, including invagination, evagination, epiboly, involution, convergence extension, migration, and ingression. Invagination is the movement of a sheet of cells into a preformed cavity. Evagination is the movement of a sheet of cells away from a preformed cavity, for example, the evaginations of the developing retinas from the lateral walls of the early forebrain. Epiboly is the spreading of cells upon a surface. Involution is the turning in of cells over a rim, for example, the involution of epiblast cells into the primitive streak. Convergence is the movement of cells toward each other. Extension is the elongation of a structure as a result of cell convergence. Migration is the movement of single cells, for example, the movement of neural crest cells throughout the developing embryo to give rise to a wide diversity of structures, such that the neural crest has been referred to as the fourth germ layer. Ingression is the movement of single cells out of a cell layer into a preformed cavity, for example, ingression of epiblast cells along the primitive streak to give rise to endoderm and mesoderm, or formation of the notochord by cells that ingress through the primitive (Hensen's) node.
Soft and Hard Tissue Repair
Published in John C Watkinson, Raymond W Clarke, Louise Jayne Clark, Adam J Donne, R James A England, Hisham M Mehanna, Gerald William McGarry, Sean Carrie, Basic Sciences Endocrine Surgery Rhinology, 2018
Sarah Al-Himdani, Ardeshir Bayat
This process involves replication and movement of the epidermal cells from the wound edges in order to reconstitute an organized, keratinized, stratified squamous epithelium. Increased mitotic activity within the basal cells of the wound edges occurs within 12 hours of wounding. Initially, migration of epidermal cells creates a delicate covering over the raw area, a process also known as ‘epiboly’. These cells then migrate, usually as a sheet, by extending lamellipodia (from the Latin lamina – thin sheet, pod – foot) from the free edge of the cut epidermis, across the defect. This process of migration is dependent on the oxygen tension present in the wound and is most rapid in hyperbaric conditions.7 ‘Contact inhibition’ prevents movement when epithelial sheets meet. Gradually, a continuous squamous cell epithelium is restored.
Toxicity assessment of biological suspensions using the dielectric impedance spectroscopy technique
Published in International Journal of Radiation Biology, 2018
S. Muñoz, J. L. Sebastián, P. Antoranz, J. P. García-Cambero, A. Sanchis-Otero
Regarding to the conductivity, the results showed a similar trend for the three viable suspensions, with a larger dispersion corresponding to the sample V1 and slightly higher values through almost the whole spectra from the sample V3. These differences would be related to the variations in structure and composition of the embryo interior during the development, considering both the animal and vegetal poles. Apart from the aforementioned differences in the animal pole among the three observed embryo stages, during the embryogenesis also the vegetal pole suffers some alterations. In fact, at earlier stages, the yolk cell is composed of yolk granules packed densely underlying the blastodisc, appearing later a peripheral layer, the yolk syncytial layer (YSL) (sample V1). Then, this layer will spread underneath the blastodisc, becoming an internal layer between animal and vegetal poles at sphere stage (embryos of V2). In the late blastula, epiboly begins and the YSL accompanies the thinning and spreading of the blastodisc over the yolk cell (embryos in V3).