Search results for "Neural crest"
showing 7 items of 17 documents
Anophthalmia-Waardenburg syndrome with expanding phenotype: does neural crest play a role?
2007
We describe a child with bilateral anophthalmia, limb anomalies, skin lesions, cerebral malformations, epilepsy, and mental retardation. This patient, according to eponymous classification, should fit into the Anophthalmia-Waardenburg syndrome, although he also presents cutaneous and cerebral manifestations never reported in this syndrome until now. These clinical findings could be explained by the new classification of brain malformations, which takes into account the role of neural crest in Waardenburg syndrome.
Regulation of neurogenesis by neurotrophins in developing spinal sensory ganglia.
2002
Neurons and glia in spinal sensory ganglia derive from multipotent neural crest-derived stem cells. In contrast to neural progenitor cells in the central nervous system, neural crest progenitors coexist with differentiated sensory neurons all throughout the neurogenic period. Thus, developing sensory ganglia are advantageous for determining the possible influence of cell-cell interactions in the regulation of precursor proliferation and neurogenesis. Neurotrophins are important regulators of neuronal survival in the developing vertebrate nervous system and, in addition, they appear to influence precursor behavior in vitro. Studies in mice carrying mutations in neurotrophin genes provide a g…
Plexiform Atypical Spitz Tumor With Rosette-Like Giant Cells. A Histologic and Immunohistochemical Study on a Case Suggesting Ganglioneuroblastic Dif…
2018
Spitz nevi, atypical Spitz tumors and Spitzoid melanoma, the three clinicopathologic forms that constitute the spectrum of the Spitz-type melanocytic lesions, share a histologic picture characterized by large spindle and/or epithelioid ganglion-like cells, with various admixtures of multinucleate bizarre cells. This remarkable cytology has always been interpreted as an unusual, as well as unexplained form of atypia. We report a case of atypical Spitz tumor with Homer Wright-like rosettes, a feature characteristic of ganglioneuroblastic proliferation. Furthermore, the ganglion-like cells of the tumor showed basophilic punctuation in the cytoplasm, reminiscent of Nissl substance, and a few ce…
Formation of Epidermal and Dermal Merkel Cells During Human Fetal Skin Development
1986
The origin of Merkel cells is still a matter of debate, specifically the question of whether they are derived from epithelial cells of the epidermis or from immigrated neural crest cells. As an argument for the latter hypothesis the occurrence of dermal, nerve-associated Merkel cells in human fetal skin has often been mentioned. Therefore, we analyzed the distribution of Merkel cells in epidermis and dermis of plantar skin of human embryos and fetuses, ranging in gestational age between 7 and 17 weeks. Merkel cells were identified by immunocytochemistry on frozen sections using antibodies against simple epithelium-type cytokeratins and by electron microscopy. In the 17-week-old fetus, 17% o…
High levels of HIF-2α highlight an immature neural crest-like neuroblastoma cell cohort located in a perivascular niche
2007
High HIF-2alpha protein levels in the sympathetic nervous system-derived childhood tumour neuroblastoma as well as immature phenotype correlate to unfavourable outcome. Here we show that a small subset of perivascularly located, strongly HIF-2alpha-positive tumour cells (MYCN amplified) lacks expression of differentiation markers, but expresses neural crest and early sympathetic progenitor marker genes such as Notch-1, HES-1, c-Kit, dHAND, and vimentin. HIF-2alpha- and CD68-positive tumour-associated macrophages were frequently found close to the immature and HIF-2alpha-positive neuroblastoma cells and as VEGF levels are high in the perivascular niche, we hypothesize that neuroblastoma neur…
Hyperplastic Conotruncal Endocardial Cushions and Transposition of Great Arteries in Perlecan-Null Mice
2002
Perlecan is a heparan-sulfate proteoglycan abundantly expressed in pericellular matrices and basement membranes during development. Inactivation of the perlecan gene in mice is lethal at two developmental stages: around E10 and around birth. We report a high incidence of malformations of the cardiac outflow tract in perlecan-deficient embryos. Complete transposition of great arteries was diagnosed in 11 out of 15 late embryos studied (73%). Three of these 11 embryos also showed malformations of semilunar valves. Mesenchymal cells in the outflow tract were abnormally abundant in mutant embryos by E9.5, when the endocardial-mesenchymal transformation starts in wild-type embryos. At E10.5, mut…
TALPID3/KIAA0586 Regulates Multiple Aspects of Neuromuscular Patterning During Gastrointestinal Development in Animal Models and Human
2021
TALPID3/KIAA0586 is an evolutionary conserved protein, which plays an essential role in protein trafficking. Its role during gastrointestinal (GI) and enteric nervous system (ENS) development has not been studied previously. Here, we analyzed chicken, mouse and human embryonic GI tissues with TALPID3 mutations. The GI tract of TALPID3 chicken embryos was shortened and malformed. Histologically, the gut smooth muscle was mispatterned and enteric neural crest cells were scattered throughout the gut wall. Analysis of the Hedgehog pathway and gut extracellular matrix provided causative reasons for these defects. Interestingly, chicken intra-species grafting experiments and a conditional knockou…