Differentiation of endostyle cells by Nkx2-1 and FoxE in the ascidian Ciona intestinalis type A: insights into shared gene regulation in glandular- and thyroid-equivalent elements of the chordate endostyle.

Due to similarities in iodine concentrations and peroxidase activities, the thyroid in vertebrates is considered to originate from the endostyle of invertebrate chordates even though it is a glandular (mucus-producing) organ for aquatic suspension feeding. Among chordates with an endostyle, urochordates are useful evolutionary research models for the study of vertebrate traits. The ascidian Ciona intestinalis forms an endostyle with specific components of glandular- and thyroid-related elements, and molecular markers have been identified for these components. Since we previously examined a simple endostyle in the larvacean Oikopleura dioica, the expression of the thyroid-related transcription factor genes, Ciona Nkx2-1 and FoxE, was perturbed by TALEN-mediated gene knockout in the present study to elucidate the shared and/or divergent features of a complex ascidian endostyle. The knockout of Ciona Nkx2-1 and FoxE exerted different effects on the morphology of the developing endostyle. The knockout of Nkx2-1 eliminated the expression of both glandular and thyroidal differentiation marker genes, e.g., vWFL1, vWFL2, CiEnds1, TPO, and Duox, while that of FoxE eliminated the expression of the differentiation marker genes, TPO and CiEnds1. The supporting element-related expression of Pax2/5/8a, Pax2/5/8b, FoxQ1, and ß-tubulin persisted in the hypoplastic endostyles of Nkx2-1- and FoxE-knockout juveniles. Although the gene regulation of ascidian-specific CiEnds1 remains unclear, these results provide insights into the evolution of the vertebrate thyroid as well as the urochordate endostyle.

Deep Sylvian Meningioma without Dural Attachment - A Case Report.

Deep Sylvian meningiomas are rare, accounting for 0.3-0.4% of all meningiomas, and mostly present in young adults and children. We report on a 32-year-old man who presented with headache but had no neurological deficits. Computed tomography of brain revealed a 24 × 19 × 21 mm3 mass lesion in the right Sylvian fissure with calcification. Magnetic resonance imaging showed that the lesion was isointense on T1- and T2-weighted images (WI), with homogenous enhancement on post-gadolinium T1WI. The lesion was surgically removed via right fronto-temporal craniotomy. The tumor was located in deep Sylvian fissure and had no dural attachment. Histopathological examination of the lesion revealed both meningothelial and fibroblastic features, thereby suggesting the diagnosis of transitional meningioma (WHO grade I), with Ki-67 labeling index of 6.9%. Thus, meningioma should be considered as a differential diagnosis of enhancing mass lesions in the Sylvian fissure even in the absence of dural tail sign, especially in young adults and children.