Relationships between neural crest cells and catecholamine in suckling mice.

In suckling mice injected i.p. with a 27 mg/kg dose of L-hydrochloric acid isoproterenol, multiple neural crest tumors developed and cell death of neural crest cells occurred. It is speculated that neural crest derivatives may be beta-receptor cells and contain regulatory units of neurotransmission mediated through cyclic AMP.     

Dysdifferentiation of the neural crest cells in the suckling mice

Zusammenfassung Nachweis, dass bei Entwicklungsstadien von Mäusesäuglingen, die mit Mitomycin C injiziert wurden, Hyperplasien mit Melanin-Ablagerungen auftraten, was mit «Dysdifferenzierungen» von Zellen der Neuralleisten zusammenhängen dürfte.     

Multiple oncogenesis of neural crest cells by steroids in suckling mice

Summary In suckling mice injected with steroids, multiple tumors occurred in the sites where neural crest cells normally are present. It is speculated that the phase of the cell cycle of the neural crest cells may have something to do with its cell surface and cellular phenotypic expression in the system mediated by cyclic AMP.     

Multiple oncogenesis of neural crest cells by steroids in suckling mice.

In suckling mice injected with steroids, multiple tumors occurred in the sites where neural crest cells normally are present. It is speculated that the phase of the cell cycle of the neural crest cells may have something to do with its cell surface and cellular phenotypic expression in the system mediated by cyclic AMP.     

Multiple APUD system (neural crest) tumors caused by endotoxin in suckling mice

Summary In suckling mice injected i. p. with endotoxin on the 1st day after birth and surviving up to the 4th day, multiple tumors and heterotopic melanin pigmentation occurred in the sites where the neural crest cells may be present.     

Mastocytosis in suckling mice

Summary In suckling mice injected intraperitoneally with mitomycin C on the 1st to 5th day after birth and sacrificed in the course of 24 or 48 h after injection, mastocytosis occurred in the oral mucosa membrane, skin of the trunk or extremities and bone marrow of extremities.     

Mastocytosis in suckling mice.

In suckling mice injected intraperitoneally with mitomycin C on the 1st to 5th day after birth and sacrificed in the course of 24 or 48 h after injection, mastocytosis occurred in the oral mucosa membrane, skin of the trunk or extremities and bone marrow of extremities.     

Light sensitivity of melanophores in neural crest explants

Résumé Les mélanophores de la crête neurale de divers amphibiens isolés in vitro se sont montrés sensibles à la lumière. A la lumière normale, ils s'étendent, mais se contractent rapidement dans l'obscurité. Cette sensibilité intrinsèque pourrait renforcer la réaction qui produit la décoloration du corps chez les larves, mais n'en est pas la cause principale.     

Role of extracellular matrix molecules in the development of the sodium current in quail mesencephalic neural crest cells

The occurrence of the voltage-dependent sodium current has been studied in developing neurons from quail mesencephalic neural crest on different substrates, using the whole-cell patch clamp technique. Explants from 9–12 somite embryos were cultured on dishes coated with type I collagen, fibronectin, laminin or on plastic dishes in a chemically defined medium. After 18 h of culture the sodium current was observed in 70% of the neurons tested, and at 24 h some of these neurons were able to generate an action potential. After 18–25 h cells grown on fibronectinor collagen I-coated dishes showed a significantly higher occurrence of the sodium current (83% and 84% respectively) as compared to cells grown on uncoated plastic dishes (51%). Moreover, in the presence of fibronectin, the current density of the sodium current was more than doubled in comparison with cells grown on other substrates.     

Evaluation of the maternal role in survival of suckling mice

Zusammenfassung Das Überleben der von der eigenen Mutter und von stammesfremden «Ammen» gesäugten Jungen wurde untersucht an Mäusen der Stämme AKR/Sp, PL/Sp und C57BL/Sp. Die Ergebnisse zeigen, dass die genetische Herkunft der Säuglinge wie auch andere, nicht genetisch bedingte Einflüsse der Mutter auf die Jungen in utero für das Überleben der Jungen ausschlaggebend ist.

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This investigation was supported in part by Public Health Service Research Grants Nos. CA 02151, CA 02903 and CA 02624 from the National Cancer Institute, and in part by an institutional grant to the Detroit Institute of Cancer Research from the United Foundation of Greater Detroit allocated through the Michigan Cancer Foundation.     

Combinatorial activity of Six1-2-4 genes in cephalic neural crest cells controls craniofacial and brain development

The combinatorial expression of Hox genes is an evolutionarily ancient program underlying body axis patterning in all Bilateria. In the head, the neural crest (NC)––a vertebrate innovation that contributes to evolutionarily novel skeletal and neural features––develops as a structure free of Hox-gene expression. The activation of Hoxa2 in the Hox-free facial NC (FNC) leads to severe craniofacial and brain defects. Here, we show that this condition unveils the requirement of three Six genes, Six1, Six2, and Six4, for brain development and morphogenesis of the maxillo-mandibular and nasofrontal skeleton. Inactivation of each of these Six genes in FNC generates diverse brain defects, ranging from plexus agenesis to mild or severe holoprosencephaly, and entails facial hypoplasia or truncation of the craniofacial skeleton. The triple silencing of these genes reveals their complementary role in face and brain morphogenesis. Furthermore, we show that the perturbation of the intrinsic genetic FNC program, by either Hoxa2 expression or Six gene inactivation, affects Bmp signaling through the downregulation of Bmp antagonists in the FNC cells. When upregulated in the FNC, Bmp antagonists suppress the adverse skeletal and cerebral effects of Hoxa2 expression. These results demonstrate that the combinatorial expression of Six1, Six2, and Six4 is required for the molecular programs governing craniofacial and cerebral development. These genes are crucial for the signaling system of FNC origin, which regulates normal growth and patterning of the cephalic neuroepithelium. Our results strongly suggest that several congenital craniofacial and cerebral malformations could be attributed to Six genes’ misregulation.     

Interactions between VEGFR and Notch signaling pathways in endothelial and neural cells

Notch cell interaction mechanism governs cell fate decisions in many different cell contexts throughout the lifetime of all Metazoan species. It links the fate of one cell to that of its neighbors through cell-to-cell contacts, and binding of Notch receptors expressed on one cell to their membrane bound ligands on an adjacent cell. Environmental cues, such as growth factors and extracellular matrix molecules, superimpose a dynamic regulation on this canonical Notch signaling pathway. In this review, we will focus on Notch signaling in the vertebrate vascular and nervous systems and examine its role in angiogenesis, neurogenesis, and neurovascular interactions. We will also highlight the molecular relationships of the Notch pathway with vascular endothelial growth factors (VEGFs) and their high-affinity tyrosine kinase VEGF receptors, key regulators of both angiogenesis and neurogenesis.