Journal of anatomy
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The transcription factors Satb2 (special AT-rich sequence binding protein 2) and Ctip2 (COUP-TF interacting protein 2) have been shown to be required for callosal and corticospinal axon growth respectively from subtypes of cerebral cortex projection neurons. In this study we investigated early stages of directed axon growth in the embryonic mouse cerebral cortex, and studied the possible correlation with the expression of Satb2 and Ctip2. Electroporation of an EYFP-expressing plasmid at embryonic day 13.5 to label developing projection neurons revealed that directed axon growth is first seen in radially migrating neurons in the intermediate zone (IZ), prior to migration into the cortical plate, as has been suggested previously. ⋯ Immunohistochemical staining through embryonic and early postnatal development revealed a significant population of Satb2/Ctip2 co-expressing cells, while retrograde axon tracing from the corpus callosum at embryonic day 18.5 back-labelled many neurons with bi-directional axon processes. However, through retrograde tracing and simultaneous immunohistochemical staining we show that these bi-directional processes do not correlate with Satb2/Ctip2 co-expression. Our work shows that although expression of these transcription factors correlates well with the appearance of directed axon growth during cortical development, the transcriptional code underlying the bi-directional axonal projections of early neocortical neurons is not likely to be the result of Satb2/Ctip2 co-expression.
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Patients with cleft left lip and palate (CLP) normally require extensive surgery from an early age up to the end of adolescence. These surgeries affect the growth of the maxillofacial complex. The degree to which the cleft itself affects growth of the maxillofacial complex remains poorly understood. ⋯ No correlations between palatal shelf elevation and maxillary arch width were found in the BCLP group. This shows that the intrinsic growth potential in patients with UCLP and BCLP is affected by a smaller palatal shelf width and larger elevation of the shelves. These deviations may result in a wider cleft.