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Case 3.2
Published in Monica Fawzy, Plastic Surgery Vivas for the FRCS(Plast), 2023
The three signalling centres act on transcription factors within the cells in the developing limb bud. One of the most important factors is the HOX protein family, and in this case of synpolydactyly, the underlying aetiology is most likely HOX D13 mutation, inherited in an autosomal dominant fashion.
Fertilization and normal embryonic and early fetal development
Published in Hung N. Winn, Frank A. Chervenak, Roberto Romero, Clinical Maternal-Fetal Medicine Online, 2021
Asim Kurjak, Ritsuko K. Pooh, Aida Salihagic-Kadic, Iva Lausin, Lara Spalldi-Barisic
During the 7th week, fast development of rhombencephalon (hindbrain) takes place. This process gives even more prominence to the head. By the use of planar mode developing, vesicles of the brain can be depicted as anechoic structure inside the head. The biggest and usually the only visible part is rhombencephalon placed on the top of the head (vertex). Diencephalon and its cavity become visible few days later. The head is strongly flexed anteriorly being in the contact with the chest. Limb buds are often visible laterally to the body.
Early Organogenesis and First Trimester
Published in Mary C. Peavey, Sarah K. Dotters-Katz, Ultrasound of Mouse Fetal Development and Human Correlates, 2021
Mary C. Peavey, Sarah K. Dotters-Katz
Early limb bud and limb formation is very similar across vertebrate species. The limb buds are visible first along the embryonic sides, with establishment of the proximal-distal and anterior-posterior axes. Differing expression of genes results in signals for specific forelimb and hind limb formation (10), and the mesoderm will differentiate into the various tissues of the limb, including the cartilage, bone, muscle, and connective tissue.
Cell-cell junctions in developing and adult tendons
Published in Tissue Barriers, 2020
Sophia K. Theodossiou, Jett B. Murray, Nathan R. Schiele
In MSCs, N-cadherin and cadherin-11 are regulators of differentiation toward cartilage and bone.117 The timing of N-cadherin expression appears especially critical for chondrogenesis. N-cadherin was initially shown to have a specific spatiotemporal expression pattern during limb bud chondrogenesis in chick.115 Shell-less embryos injected during the cell condensation stage at HH22-24 with N-cadherin blocking antibodies failed to undergo chondrogenesis, and had other gross developmental and pattern deformities, likely due to widespread disruption of cell adhesion.115 The same study also treated in vitro micromass cultures of chick limb mesenchymal cells with N-cadherin blocking antibodies. As in the in vivo experiments, cells treated with N-cadherin blocking antibodies did not undergo aggregation and condensation, and chondrogenesis was inhibited.115 As N-cadherin expression is highest during the cellular condensation phase, blocking N-cadherin during cellular condensation is especially detrimental to chondrogenesis.
Usefulness of zebrafish in evaluating drug-induced teratogenicity in cardiovascular system
Published in Drug and Chemical Toxicology, 2019
Ryo Watanabe, Yuki Nakanishi, Daisuke Nijoukubo, Hiroki Teraoka, Hiroyuki Ogasawara, Kazuhiko Mori
Teratogenicity is one of the serious concerns associated with pharmaceutical drug development. At the preclinical screening phase, several in vitro systems, such as a limb bud micromass culture system (Flint 1993), a whole embryo culture (WEC) system (Webster et al.1997), and a mouse embryonic stem cell test (EST) (Scholz et al.1999), are widely used to detect the potential teratogenicity of candidates. These systems have been reported to adequately detect the potential teratogenicity of some drugs, which showed teratogenicity in vivo in rodent and rabbit studies, with high sensitivity (Genschow et al.2002). However, these test systems have inherent drawbacks. For example, the limb bud micromass culture and WEC systems are not effective for the assessment of drug candidates during organogenesis due to the exposure timing. In addition, the mouse EST system, which evaluates the effect of test compounds on heart rate by using differentiated cardiomyocytes, is unable to assess the whole-embryo developmental process (Chapin et al.2008, Kroese et al.2015). Furthermore, it is difficult to detect teratogenic features, such as hypoplasia of the limbs and external ear malformation, caused by thalidomide in humans by using the above-mentioned methods. Recently, a new assay system using zebrafish eleutheroembryos was reported that could detect teratogenicity caused by thalidomide with similar phenotypic outcomes (Ito et al.2010).
The effect of nanofibre-based polyethersulfone (PES) scaffold on the chondrogenesis of human induced pluripotent stem cells
Published in Artificial Cells, Nanomedicine, and Biotechnology, 2018
Hossein Mahboudi, Masoud Soleimani, Seyed Ehsan Enderami, Mousa Kehtari, Hana Hanaee- Ahvaz, Hossein Ghanbarian, Mojgan Bandehpour, Shahrzad Nojehdehi, Samaneh Mirzaei, Bahram Kazemi
In our study, we have demonstrated increasing chondrogenic differentiation of IPSC in vitro by using PES scaffold. This could be attributed to the unique properties of PES scaffolds. The three-dimensional IPSC seeded constructs display a cartilage-like morphology, containing chondrocyte-like cells surrounded by abundant cartilaginous matrix, as seen by SEM and ICC. Expressions of cartilage specific genes are detected at mRNA level by RT-PCR. The level of IPSC chondrogenesis in the PES scaffold appears to higher than scaffold free method. Taken together, these observations strongly suggest that the nanofibrous based scaffold (PES) effectively help to IPSC chondrogenesis. The most commonly used method to promote chondrogenesis of IPSC in vitro is to maintain them as a high cell-density culture system. In these systems, environment thus simulates the act of cellular condensation during embryonic limb bud development, where cell–cell interactions have been shown to be critical for the initiation of chondrogenesis [47–49].