Thalamic activity-dependent specification of sensory input neurons in the developing chick entopallium.

During development, cell-intrinsic and cell-extrinsic factors play important roles in neuronal differentiation; however, the underlying mechanisms in nonmammalian species remain largely unknown. We here investigated the mechanisms responsible for the differentiation of sensory input neurons in the chick entopallium, which receives its primary visual input via the tectofugal pathway from the nucleus rotundus. The results obtained revealed that input neurons in the entopallium expressed Potassium Voltage-Gated Channel Subfamily H Member 5 (KCNH5/EAG2) mRNA from embryonic day (E) 11. On the other hand, the onset of protein expression was E20, which was 1 day before hatching. We confirm that entopallium input neurons in chicks were generated during early neurogenesis in the lateral and ventral ventricular zones. Notably, neurons derived from the lateral (LP) and ventral pallium (VP) exhibited a spatially distinct distribution along the rostro-caudal axis. We further demonstrated that the expression of EAG2 was directly regulated by input activity from thalamic axons. Collectively, the present results reveal that thalamic input activity is essential for specifying input neurons among LP- and VP-derived early-generated neurons in the developing chick entopallium.

Klippel-Feil syndrome associated with congenital cervical dislocation: report of an autopsy case.

Klippel-Feil syndrome is an uncommon congenital anomaly that is characterized by abnormal fusion of the cervical vertebrae and occasionally accompanied by various anomalies of other bones and internal organs. We report the autopsy case of a 5-year-old girl with this syndrome ssociated with congenital cervical dislocation, with special reference to the pathological findings of the vertebral column and spinal cord. Principal anomalies of the cranio-spinal axis were as follows: partial defect of the clivus, scoliosis, hypoplasia of the whole cervical vertebrae, anterior dislocation of C7 with S-shaped deformity of the spinal canal, fusion of the spinous processes of the cervical and thoracic vertebrae, fusion of the vertebral bodies of C6 and C7 with collapse of C7, and spina bifida occulta of L5 and S1. In addition to these skeletal anomalies, subarachnoid vascular malformation in the medulla oblongata, a bronchogenic cyst in the posterior mediastinum, anomalous lobation of the lungs, and the mobile cecum were found at autopsy. The cervical cord showed an increase of the antero-posterior diameter, multifocal spongy changes of the white matter, and partial branching or duplication of the central canal. The brain showed features of anoxic encephalopathy. The partial defect of the clivus, C7 dislocation, and various lesions of the medulla oblongata and cervical cord were interpreted as integral components of, or lesions closely associated with, Klippel-Feil syndrome.

Malignant peripheral nerve sheath tumor with fibroblastic differentiation in a patient with neurofibromatosis type 1: imprint cytological findings.

BACKGROUND: Malignant peripheral nerve sheath tumor (MPNST) is a heterogeneous group of neoplasms that shows divergent differentiation potential, and the cytological findings are largely nonspecific. There are no previous reports specifically alluding to the cytological findings of MPNST showing fibroblastic differentiation (fibroblastic MPNST). CASE: A 59-year-old woman with neurofibromatosis type 1 developed a rapidly enlarging tumor on the scalp. A metastatic lesion in the ileum was examined cytologically. Irregularly shaped clusters of spindle cells with wavy or buckled nuclei and fibrillary cytoplasm were found as well as many similar isolated cells. Histopathologically, the tumor showed a spindle cell sarcomatous appearance typical of MPNST. Immunohistochemically, the tumor cells were negative for S-100 protein and epithelial membrane antigen but immunoreactive for vimentin, CD10 and CD34. Ultrastructurally, the tumor cells were not invested by the basal lamina and had abundant rough-surfaced endoplasmic reticulum and a subplasmalemmal accumulation of microfilaments with dense patches. These immunohistochemical and ultrastructural findings were consistent with fibroblastic or myofibroblastic differentiation. CONCLUSION: Although there are no cytological findings specific for fibroblastic MPNST, the wide spectrum of differentiation in MPNST should be kept in mind during cytological examination of soft tissue sarcomas.