OBSERVATIONS ON THE PATHOGENESIS OF SPINA BIFIDA IN CHICK EMBRYOS: FORKING OF THE NEURAL TUBE

Autor: J. Rokos
Rok vydání: 1976
Předmět:
Zdroj: Neuropathology and Applied Neurobiology. 2:111-124
ISSN: 1365-2990
0305-1846
DOI: 10.1111/j.1365-2990.1976.tb00489.x
Popis: Observations on the pathogenesis of spina bifida in chick embryos: forking of the neural tube Forking is an early malformation in which the neural tube is split into 2–6 tubules, walled off by neuroepithelium. Occasionally the undivided tube proximal to forking of the neural tube (FNT) or some of the secondary tubules, may show marked cystic dilatation. FNT may occur at any level of the cord and hence its development is not related to the caudal cell mass (‘tail node’). It is important that FNT may be covered by intact ectoderm or may occur simultaneously with myeloschisis. Spina bifida (SB) probably develops in those cases of FNT in which marked increase in volume of the malformed tube, due either to cystic dilatation or to presence of multiple tubules, prevents the mesoderm from growing between the ectoderm and the neural tissue. FNT seems to result from primary damage to the neural tissue around the posterior neuropore, followed by formation of supernumerary tubules from fragmented neuroepithelium. This process does not interfere with normal growth of the ectoderm. The likely consequences of FNT are deduced tentatively from a comparison with cases of fully developed spontaneous human SB associated with diastematomyelia (DM). FNT is related to variable degree of myelodysplasia, diplomyelia, myelocystocele and meningocele. The hypothesis (Rokos, 1975) that meningocele is a manifestation of anteroposterior FNT (anteroposterior DM) is supported by the present findings.
Databáze: OpenAIRE
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