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Most olfactory bulb (OB) interneurons are derived from neural stem cells in the subventricular zone (SVZ) and migrate to the OB via the rostral migratory stream (RMS). Mature dopaminergic interneurons in the OB glomerular layer are readily identified by their synaptic activity-dependent expression of tyrosine hydroxylase (TH). Paradoxically, TH is not expressed in neural progenitors migrating in the RMS, even though ambient GABA and glutamate depolarize these progenitors. In forebrain slice cultures prepared from transgenic mice containing a GFP reporter gene under the control of the Th 9kb upstream regulatory region, treatment with histone deacetylase (HDAC) inhibitors (either sodium butyrate, Trichostatin A or Scriptaid) induced Th-GFP expression specifically in the RMS independently of depolarizing conditions in the culture media. Th-GFP expression in the glomerular layer was also increased in slices treated with Trichostatin A, but this increased expression was dependent on depolarizing concentrations of KCl in the culture media. Th-GFP expression was also induced in the RMS in vivo by intra-peritoneal injections with either sodium butyrate or valproic acid. Quantitative RT-PCR analysis of neurosphere cultures confirmed that HDAC inhibitors de-repressed Th expression in SVZ-derived neural progenitors. Together, these findings suggest that HDAC function is critical for regulating Th expression levels in both neural progenitors and mature OB dopaminergic neurons. However, the differential responses to the combinatorial exposure of HDAC inhibitors and depolarizing culture conditions indicate that Th expression in mature OB neurons and neural progenitors in the RMS are regulated by distinct HDAC-mediated mechanisms.

In the adrenal medulla, binding of the immediate early gene (IEG) proteins, EGR-1 (ZIF-268/KROX-24/NGFI-A) and AP-1, to the tyrosine hydroxylase (Th) proximal promoter mediate inducible Th expression. The current study investigated the potential role of EGR-1 in inducible Th expression in the olfactory bulb (OB) since IEGs bound to the AP-1 site in the Th proximal promoter are also necessary for activity-dependent OB TH expression. Immunohistochemical analysis of a naris-occluded mouse model of odor deprivation revealed weak EGR-1 expression levels in the OB glomerular layer that were activity-dependent. Immunofluorescence analysis indicated that a majority of glomerular cells expressing EGR-1 also co-expressed TH, but only small subset of TH-expressing cells contained EGR-1. By contrast, granule cells, which lack TH, exhibited EGR-1 expression levels that were unchanged by naris closure. Together, these finding suggest that EGR-1 mediates activity-dependent TH expression in a subset of OB dopaminergic neurons, and that there is differential regulation of EGR-1 in periglomerular and granule cells.

The micro-and nanosize surface topography of dental implants has been shown to affect the growth of surrounding cells. in this study, standardized and controlled periodic nanopatterns were fabricated with nanosized surface roughness on titanium substrates, and their influence on bone marrow stromal cells investigated. Cell proliferation assays revealed that the bare substrate with a 1.7 nm surface roughness has lower hydrophilicity but higher proliferation ability than that with a 0.6 nm surface roughness. further, with the latter substrate, directional cell growth was observed for line and groove patterns with a width of 100 nm and a height of 50 or 100 nm, but not for those with a height of 10 or 25 nm. With the smooth substrate, time-lapse microscopic analyses showed that more than 80% of the bone marrow cells on the line and groove pattern with a height of 100 nm grew and divided along the lines. As the nanosized grain structure controls the cell proliferation rate and the nanosized line and groove structure (50-100 nm) controls cell migration, division, and growth orientation, these standardized nanosized titanium structures can be used to elucidate the mechanisms by which surface topography regulates tissue responses to biomaterials.

Considering the increased interest in cell-based bone regeneration, it is necessary to reveal the fate of transplanted cells and their substantive roles in bone regeneration. The aim of this study was to analyze the fate of transplanted cells and the effect of osteogenic cell transplantation on calvarial bone defect healing. An anti-apoptotic protein, heat shock protein (HSP) 27, was overexpressed in osteoblasts. Then, the treated osteoblasts were transplanted to calvarial bone defect and their fate was analyzed to evaluate the significance of transplanted cell survival. Transient overexpression of Hsp27 rescued MC3T3-E1 osteoblastic cells from H2 O2 -induced apoptosis without affecting osteoblastic differentiation in culture. Transplantation of Hsp27-overexpressing cells, encapsulated in collagen gel, showed higher proliferative activity, and fewer apoptotic cells in comparison with control cells. After 4-week of transplantation, both control cell- and Hsp27 overexpressed cell-transplanted groups showed significantly higher new bone formation in comparison with cell-free gel-transplantation group. Interestingly, the prolonged survival of transplanted osteoblastic cells by Hsp27 did not provide additional effect on bone healing. The transplanted cells in collagen gel survived for up to 4-week but did not differentiate into bone-forming osteoblasts. In conclusion, cell-containing collagen gel accelerated calvarial bone defect healing in comparison with cell-free collagen gel. However, prolonged survival of transplanted cells by Hsp27 overexpression did not provide additional effect. These results strongly indicate that cell transplantation-based bone regeneration cannot be explained only by the increment of osteogenic cells. Further studies are needed to elucidate the practical roles of transplanted cells that will potentiate successful bone regeneration. J. Cell. Physiol. 231: 1974-1982, 2016. © 2016 Wiley Periodicals, Inc.

No abstract

Metal alloys have long been used in the dental profession. Although a range of acrylic materials have been introduced recently, metal alloys are still widely used in dental prostheses.Dental metal allergy refers to the symptoms of contact dermatitis, which is suspected to be associated with the use of metal alloys in dental treatment; however, it does not necessarily reflect a causal relationship. Since being reported in 1928, several clinical, in vitro, and animal studies have investigated its prevalence and etiology [1]. Nevertheless, the cause of dental metal allergy remains poorly understood, despite a recent increase in the number of affected patients in Japan. Although the pathophysiological mechanisms remain unclear, several skin diseases have been suggested to be associated with dental metal alloys, including palmoplantar pustulosis (PPP), dyshidrotic eczema, contact dermatitis, and oral lichen planus[2-6]. Specific types of dermatitis have also been reported to be associated with periodontal disease and apical periodontitis [2,4,[7][8][9][10][11]. Studies suggest that the treatment of chronic inflammation, and the replacement of dental metals present in the prostheses may result in the improvement of the skin diseases.This study aimed to determine the relationship between dental metal allergy, PPP, and periodontitis among a group of patients from a dental metal allergy clinic. Materials and Methods PatientsThis study included 436 patients who visited our dental metal allergy clinic between April 1, 2009, and March 31, 2016. All patients provided signed informed consent to participate in the clinical study and to undergo dental treatment, patch testing, and electron probe microanalysis (EPMA). Patients who did not consent to the examination or inclusion in the clinical study, or received a diagnosis that did not require further examination, were excluded. The study protocol was approved by the Research Ethics Committee of our university (2009-5044) and was performed in accordance with the Declaration of Helsinki.

Purpose/objectives: Self-assessment is an essential skill for dental professionals. Understanding global trends in self-assessment can highlight the learning needs of students across a diversity of cultural backgrounds. The aim of this study is to compare the self-assessment ability of dental students in the United States and Japan, where cultural backgrounds may differ.Methods: Students in the United States (n = 176) completed a typodont premolar and anterior Class II and Class III preparation and restoration. Students in Japan (n = 175) completed a typodont premolar crown preparation. Students and faculty then evaluated the student performance using rubrics for each respective procedure. The difference between the student's self-assessment score and the average faculty score (S-F gap) was calculated and the data were analyzed. Results:The mean S-F gap was 2.8% in Japan and 7.6% in the United States. This indicates that Japanese students tended to assess themselves closer to their faculty graders than students in the United States. On average, students in both countries scored themselves higher than their faculty graders. Students in the United States more frequently overestimated their performance and students in Japan more frequently underestimated their performance. For students in the lower quartile, the mean S-F gap was 5.1% in Japan and 14.6% in the United States, indicating a large cultural discrepancy in the lower quartile groups.Conclusions: Although different preclinical procedures were compared, our findings demonstrated that Japanese students may score themselves more closely to their faculty assessors than students in the United States. Further investigation with more students completing the same preclinical activity will be needed.