Lingual thyroid: case report.

A sixteen year old male presented with progressive dysphagia, dysphonia and haemoptysis over eight months. Radionuclide studies and computed tomographic scans confirmed an only functional thyroid gland at the base of tongue which was excised wholly via mandibular split transoral route and patient put on thyroxin replacement therapy.

Adult rat olfactory nerve ensheathing cells are effective promoters of adult central nervous system neurite outgrowth in coculture.

A coculture method is described for ensheathing glial cells from adult rat olfactory nerve, serving as a substrate for the regrowth of neurites from adult rat retinal ganglion cells. Immunocytochemically identified phenotypes present in primary cultures of olfactory nerve cells are described, and their ability to promote neurite outgrowth is compared with neonatal astrocytes and Schwann cells, with other nonglial cells, and with laminin. Ensheathing cell cultures were more effective than any other substrate tested and also directed the orientation of regrowing neurites. In comparison with cultured Schwann cells, which released neurotrophic factors into the culture medium, there was no evidence of a similar activity in ensheathing cell cultures. Combinations of ensheathing cell-conditioned medium and substrates of laminin, merosin, or 3T3 cells also failed to show the release of factors enhancing either survival or neurite outgrowth from retinal ganglion cells. Evidence is presented for a partial inhibition of neurite outgrowth in the presence of calcium channel antagonists or an intracellular calcium-chelating reagent. This provides evidence for a contribution from an intracellular calcium signaling mechanism, possibly implicating ensheathing cell adhesion molecules in promoting neurite outgrowth.

Spontaneous immortalisation of ensheathing cells from adult rat olfactory nerve.

In this report, we describe the isolation of a cell line, Rolf B1.T, from cultures of adult rat olfactory nerve cells. Rolf B1.T cells have an antigenic phenotype which closely resembles that of olfactory ensheathing cells. In routine culture conditions, Rolf B1.T cells constitutively express glial fibrillary acidic protein, S1OO, the low-affinity neurotrophin receptor p75 NGF, laminin, tenascin, and the neural cell adhesion molecule (N-CAM); a variable proportion of the cells also express cadherin, which is regulated by local culture conditions and is associated positively with cell proliferation status. We provide evidence that the association may be indirect and linked to a related parameter such as local cell density. Rolf B1.T cells arose from a population of less well-differentiated cells after a spontaneous immortalisation event. The cells retain many characteristics of normal cells, are dependent on serum growth factors for their proliferation, and fail to grow in semi-solid agar. Rolf B1.T cells support the regrowth of neurites from adult retinal ganglion cells in vitro in a heterologous co-culture system and will have potential value in investigations into the mechanisms of glial support for axonal regeneration from adult mammalian central neurons.