Embryogenesis in vitro

Wolff, Étienne

doi:10.1016/b978-1-4831-9797-5.50022-6

Cited by 2 publications

(1 citation statement)

References 96 publications

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“…The proven necessity of intimate spatial relationships between cells of some developing systems indicates that factors arising from cellular contacts are essential to full typespecific differentiation.2 The complexity of such requirements shifts with age or stage of development.3 Critical interactions and mutual contributions between different tissues, eg, epithelium and mesoderm, in early organogenesis are, moreover, similarly well documented although the chemical identity of the inductors is largely unknown. 2,4 The cerebellum of the newborn mouse is extremely immature, showing little of the complex structure and cyto-architecture of the adult. It is unmyelinated at birth and myelinates regularly after explantation in vitro.…”

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confidence: 99%

Myelin Formation in Vitro

Allerand¹

1968

Arch Neurol

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The role of cell and tissue interactions in the differentiation and development of the nervous system has been little investigated.Notwithstanding the spectacular domination of nervous tissue during the early stages of vertebrate embryogenesis, most of the factors governing morphological and functional differentiation of the various neuronal types are still obscure, and the origins of regional differences are poorly understood. The proven necessity of intimate spatial relationships between cells of some developing systems indicates that factors arising from cellular contacts are essential to full typespecific differentiation.2 The complexity of such requirements shifts with age or stage of development.3 Critical interactions and mutual contributions between different tissues, eg, epithelium and mesoderm, in early organogenesis are, moreover, similarly well documented although the chemical identity of the inductors is largely unknown.2,4The cerebellum of the newborn mouse is extremely immature, showing little of the complex structure and cyto-architecture of the adult. It is unmyelinated at birth and myelinates regularly after explantation in vitro. Mature cultures of mouse cerebellum have been shown to consist of many of the nervous elements present in the adult in vivo5·6 (C. D. Allerand, unpublished data) despite a certain loss in architectonics inher¬ ent in the in vitro situation.The present investigation was designed to study the significance of endogeneous in¬ fluences on cerebellar development in vit¬ ro after one of us (CD.A.) observed that explants which accidentally floated together and coalesced along one margin seemed to myelinate better than those remaining sepa¬ rated. Using the formation of myelin sheaths as a measurable parameter of neuronal de¬ velopment, it will be shown that placing two expiants in contiguity markedly enhances the frequency of myelination, accelerates the rate of myelin sheath formation, and signifi¬ cantly increases the extent of myelin distri¬ bution within each expiant. Of particular interest is the demonstration that this induc¬ tive effect is augmented further by pairing contiguous expiants according to their topo¬ graphic position in situ. Placing expiants in contiguity provides a reliable method for obtaining optimally myelinated cerebellar cultures and results in a model system in which in vitro and in vivo myelinogenesis become more comparable. Materials and MethodsThe cerebellum was removed from newborn albino Paris RIII mice (littermates) after cold anesthesia at -20 C for five minutes and dis¬ sected in a few drops of nutrient medium at 4 C. The meninges and chorioid plexus were stripped off, and each cerebellum was divided by parasagittal section into eight expiants of approximately equal size (Fig 1). Two expiants were placed on a collagen-coated coverslip, fed a drop (0.04 to 0.05 ml) of nutrient medium and maintained in a Maximow double coverslip assembly according to the general method of Bornstein and Murray.7 The expiants were placed either widely separated (...

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confidence: 99%