Human bone marrow-derived mesenchymal stem cells (hMSCs) are considered a desirable cell source for autologous cell transplantation therapy to treat nervous system injury due to their ability to differentiate into specific cell types and render the tissue microenvironment more favorable for tissue repair by secreting various growth factors. To potentiate their possible trophic effect, hMSCs were induced without genetic modification to adopt characteristics of Schwann cells (SCs), which provide trophic support for regenerating axons. The induced hMSCs (shMSCs) adopted a SC-like morphology and expressed SC-specific proteins including the p75 neurotrophin receptor, which correlated with cell-cycle exit. In addition, shMSCs secreted higher amounts of several growth factors, such as hepatocyte growth factor (HGF) and vascular endothelial growth factor (VEGF) when compared with uninduced hMSCs. Coculture of shMSCs with Neuro2A cells significantly increased neurite outgrowth and cell proliferation but decreased cell death. Transplantation of shMSCs in an ex vivo model of spinal cord injury dramatically enhanced axonal outgrowth, which was mediated by HGF and VEGF secretion and also decreased cell death. These results demonstrate that shMSCs could serve as an endogenous source of neurotrophic growth factors to facilitate axonal regeneration while at the same time protecting the resident cells at the site of tissue injury. We propose that these induced hMSCs without genetic modification are useful for autologous cell therapy to treat nervous system injury.

Micro-computed tomography (MCT) is a noninvasive technique for visualizing morphological characteristics of teeth in a detailed and accurate manner, without causing any tooth destruction. A large amount of information can be obtained from such scans. The slices can be recreated in any plane, and the data can be represented as either two-dimensional (2D) or three-dimensional (3D) images. In addition, the internal and external anatomy can be demonstrated simultaneously or separately, and the images can be assessed qualitatively and quantitatively. However, only the qualitative accuracy of MCT had been evaluated previously. The aim of the present study was to evaluate the accuracy of MCT quantitatively by comparing the values obtained by MCT with those of other imaging methods. Twelve teeth were scanned using a desktop X-ray micro-CT scanner, and the images were reconstructed and measured. Values obtained by direct measurement served as the primary reference for linear measurements. Measurements made by a 3D scanner and by photography were additional references. MCT was found to be a reliable method of making linear measurements and may be a useful device for measuring distance and for observing both internal and external tooth structure using the reconstructed 3D form.

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The placement of dental implants in the molar region of the maxilla is often difficult because of insufficient bone volume and the inferior bone quality. In order to avoid these limitations, the pillar of bone, which is composed of the maxillary tuberosity, the pyramidal process of the palatine bone and the pterygoid process of the sphenoid bone, was introduced for implant placement. In fact, the pyramidal process is the posterior structure where implants are placed but until now, there is no available data of the size or shape of the pyramidal process. Therefore, we measured the height, anteroposterior distance and mediolateral distance of the pyramidal process and observed the shape of lateral and posterior surfaces of the pyramidal process of 54 Korean edentulous dry skulls in this study. The height was 13.1 mm (male: 13.6 mm, female: 12.4 mm). The anteroposterior distance was 6.5 mm (male: 6.7 mm, female: 6.1 mm). The mediolateral distance was 9.5 mm (male: 9.9 mm, female: 9.0 mm). The most common type was the right-angled triangle in the lateral surface (44.4%) and in the posterior surface (66.7%). There was no statistical significance between the male and the female in all items (P > 0.05). These results provide anatomical features in relation to placement of dental implants in the molar region of the maxilla and would be useful in treatment planning of partially or completely edentulous patients.