Biomedical subjects

Shigemi Goto

Publications and source records attributed to Shigemi Goto.

10 recordsLinked to original sources

PubMed2006

3D-CT evaluation of facial asymmetry in patients with maxillofacial deformities.

OBJECTIVE: The aims of this study were to characterize the symmetrical features of patients with facial deformities and to suggest a classification system for facial asymmetry based on 3-dimensional-computed tomography (3D-CT) evaluation. STUDY DESIGN: Preoperative CT images were investigated for 49 patients with maxillofacial deformities. Asymmetry indices were calculated for some landmarks in the maxilla, mandibular body and the mandibular ramus regions. RESULTS: Asymmetry was observed most frequently in the mandibular body region. The subjects were divided into 3 groups. Subjects without any asymmetry in the 3 regions were classified as Group I (44.9%). Groups II or III were defined for subjects without or with maxillary region asymmetry, respectively, and they were subcategorized. In Group IIA (8.2%), asymmetry was shown solely in the mandibular body region, and in Group IIB (18.4%), additional asymmetry was shown in the mandibular ramus region. Group IIIA (6.1%) showed asymmetry only in the maxillary region, and Group IIIB (22.4%) showed asymmetry in all 3 regions. CONCLUSION: The 3D-CT classification for facial asymmetry has the potential to replace the conventional cephalometric classification.

Case-Control Studies↗

PubMed2005

Hypoxic stress enhances osteoclast differentiation via increasing IGF2 production by non-osteoclastic cells.

Development of bone depends on a continuous supply of bone-degrading osteoclasts. Although several factors such as cytokines and integrins have been shown to be important for osteoclast recruitment, their mechanism of action is poorly understood. In this study, we demonstrated the enhancement of osteoclast formation by hypoxia and investigated the molecular mechanisms involved. Primary mouse bone marrow cells were cultured in normoxic and hypoxic conditions, and RNA was prepared from each group of cells. Total RNAs were applied to a DNA microarray analysis and then RT-PCR was performed to confirm the microarray data. The most interesting finding of our microarray analysis was upregulation of insulin-like growth factor 2 (IGF2) and stromal cell-derived factor 1 (SDF1) under hypoxic conditions. RT-PCR analysis revealed that IGF2 expression was markedly upregulated in the non-osteoclastic cells. The addition of exogenous IGF2 increased the number of osteoclastic TRAP-positive multinuclear cells formed under normoxic conditions, whereas the addition of exogenous SDF1 did not change osteoclast formation. These results suggest that the upregulation of IGF2 derived from non-osteoclastic cells might be a crucial factor for osteoclast differentiation.

Adaptation, Physiological↗

PubMed2005

ATP-stimulated interleukin-6 synthesis through P2Y receptors on human osteoblasts.

We investigated the effect of extracellular adenosine triphosphate (ATP) on the production of interleukin (IL)-6, whose molecules are capable of stimulating the development of osteoclasts from their hematopoietic precursors as well as are involved in signal transduction systems in human osteoblastic SaM-1 cells. These human osteoblasts constitutively expressed P2X4, P2X5, P2X6, P2Y2, P2Y5, and P2Y6 purinergic receptors. ATP increased gene- and protein-expression of IL-6 in SaM-1 cells. The expression of the IL-6 mRNA was maximal at 1h, and the increase in IL-6 synthesis in response to ATP (10-100 microM) occurred in a concentration-dependent manner. Over the same concentration range of the nucleotide that was effective for IL-6 synthesis, ATP caused an increase in the intracellular Ca(2+) concentration ([Ca(2+)](i)), which increase was inhibited by pretreatment with suramin, a P2Y receptor antagonist, or 2-aminoethoxydiphenyl borate (2-APB), an inositol 1,4,5-trisphosphate receptor blocker, but not by the extracellular Ca(2+)-chelating agent EGTA. The pretreatment of SaM-1 cells with suramin or 2-APB also inhibited the increase in IL-6 synthesis in response to ATP. These findings suggest that extracellular ATP-induced IL-6 synthesis occurs through P2Y receptors and mobilization of Ca(2+) from internal stores in human osteoblastic cells.

Adenosine Triphosphate↗

PubMed2005

Can cephalometric indices and subjective evaluation be consistent for facial asymmetry?

The purpose of this study was to investigate the relationship between the subjective evaluation of facial asymmetry and seven cephalometric indices. Ten orthodontists subjectively evaluated the frontal photographs of 100 subjects and categorized them into three categories, ie, category I--symmetrical view; category II--a little asymmetry not requiring treatment; and category III--marked asymmetry requiring treatment. Seven indices that were used to evaluate facial asymmetry were determined using frontal cephalographs of these patients. Interobserver agreement was assessed using Cohen's kappa statistic. Agreement among the observers for category III was higher than for categories I and II. To define the characteristics of each category, the cephalometric indices, which at least eight observers agreed on, were compared between the categories. No differences were found in any of the indices between categories I and II. Five indices showed differences between category III and the other categories. Among them, the distance of Me from the vertical reference line was the most relevant index for the subjective evaluation of facial asymmetry. When a discrepancy is found between skeletal measurements and a subjective evaluation, the influence of soft tissue structures should be considered in facial asymmetry.

Adolescent↗

PubMed2005

Inhibitory activity on matrix metalloproteinases and cell-proliferating activity of tissue inhibitor of metalloproteinases-1 (TIMP-1)-contrastive difference between human and bovine TIMP-1s on mouse cell proliferation.

Either human or bovine TIMP-1 inhibited matrix metalloproteinase (MMP) activities, such as collagenolytic, gelatinolytic and caseinolytic, expressed by mouse cells as well as those expressed by human cells. Bovine TIMP-1 stimulated the proliferation of both human and mouse cells, but human TIMP-1 only proliferate human cells and not mouse cells indicating that the cell-proliferating activity has more strict species specificity than MMP inhibitory activity. All the results from [(3)H]thymidine incorporation, the phosphorylation of tyrosine-containing cellular proteins and extracellular-signal-regulated protein kinases supported the cell-proliferating properties of both human and bovine TIMP-1s. Human TIMP-1 seems not to bind to TIMP-1 receptors on mouse cells.

Animals↗

PubMed2005

Application of direct laminate veneer for enamel protection during orthodontic treatment: an in vivo evaluation.

The aims of this study were to examine the enamel protective effect of a direct laminate veneer against acidic conditions, measure the amount of fluoride released from the veneer and which was taken up by the enamel, as well as evaluate the usefulness of the veneer for orthodontic treatment. First, a veneer was applied to rabbit incisors. Then, apart from using profile measurement microscope and electron probe microanalyzer to measure the roughness and fluoride concentration in the enamel of veneer-covered tooth surface, those of the uncovered adjacent tooth surface were measured too. It was found that the veneer protected the enamel surface from acidic conditions. Furthermore, fluoride ions were taken up by both the uncovered adjacent enamel area as well as by the covered area. These findings suggested that covering the enamel surface with a direct laminate veneer before bracket bonding might be a valuable means of tooth protection and caries prevention.

Acrylic Resins↗

PubMed2005

The use of bioabsorbable implants as orthodontic anchorage in dogs.

The purpose of this study was to investigate the possibility of using a bioabsorbable implant as orthodontic anchorage. The implant under investigation in this study was a miniscrew, 2.0 mm x 8.0 mm, made from poly-L-lactic acid (PLLA; molecular weight: 200,000), a bioabsorbable bone-bonding material. The implants were placed in the mandibles of eight male beagle dogs. After implantation, traction was immediately applied to the third premolar (P3) using the implant as anchorage. After the completion of each study period (three and six months) following installation, tensile test, histological examination, and molecular weight measurement were performed. The results suggested that the bioabsorbable implant evaluated had favorable biocompatibility and strength, and that it showed promising potential for use in orthodontic treatment.

Absorbable Implants↗

PubMed2004

Effect of tensile force on the expression of IGF-I and IGF-I receptor in the organ-cultured rat cranial suture.

Insulin-like growth factors (IGFs) play an important role in the regulation of bone metabolism. In this study, we investigated changes in the expression of IGF-I and IGF-I receptor and cell proliferation when a continuous tensile force was applied to the cranial suture of cultured rat calvaria. The parietal bones with the midsagittal suture were removed from male Wistar rats (19-days old), cultured for 24h, and divided into two groups. In the experimental group, tensile force (3 x 10(-3)N) was applied by helical springs to the midsagittal suture, whereas helical springs with no tension (0 N) were set in the control group. The tensile force significantly increased the expression of both IGF-I mRNA and protein (P < 0.05). By using in situ hybridisation, we also confirmed that IGF-I and IGF-I receptor mRNAs were localized in osteoblast-like and fibroblastic cells subjected to the tensile force. Also, this force stimulated the proliferation of osteoblast-like and fibroblastic cells in calvaria, without affecting their alkaline phosphatase activity. These results indicate that a tensile force applied to a cranial suture can cause an increase in the production of IGF-I and IGF-I receptors in osteoblast-like and fibroblastic cells, and this increase in IGF-I may cause the proliferation of the cells in an autocrine or paracrine manner.

Animals↗

PubMed2004

Indirect laminate veneers as an indirect bonding method.

Indirect bracket bonding methods that use individual tooth transfer trays offer several benefits compared to direct bonding techniques, as well as to indirect bonding systems that use transfer trays that include all of the teeth. Precise and correct bracket position presents the most significant advantage of all indirect bonding procedures, but this new indirect bracket bonding technique also provides unprecedented enamel protection and caries prevention. In addition, it provides accuracy for the recementation of any loose, broken, or lost brackets at their previous sites. This article presents the rationale and a step-by-step guide for implementing this indirect bracket bonding system.

Dental Bonding↗

PubMed2003

Involvement of p38MAP kinase in bone morphogenetic protein-4-induced osteoprotegerin in mouse bone-marrow-derived stromal cells.

Osteoprotegerin (OPG)/osteoclastogenesis inhibitory factor is a recently identified cytokine that belongs to the tumour necrosis factor receptor superfamily and regulates bone mass by inhibiting osteoclastic bone resorption. This study found that bone morphogenetic protein (BMP)-4 markedly increased the level of soluble OPG in the mouse bone-marrow-derived stromal cell line, ST2. In contrast, BMP-4 showed no effect on OPG ligand production in ST2 cells under similar conditions. Using an in vitro immunocomplex kinase assay, BMP-4 was found to activate p38 mitogen-activated protein (MAP) kinase. Pre-treatment of ST2 cells with SB203580 (a specific inhibitor of p38MAP kinase) inhibited BMP-4-induced increase in OPG, although PD98059 (a specific inhibitor of classic MAP kinase cascade) showed no effect on OPG production. These results clearly suggest that activation of the p38MAP kinase pathway is necessary for BMP-4-induced OPG induction in ST2 cells.

Animals↗