Haruhide Kanegae

Serum Calcium-decreasing Factor, Caldecrin, Inhibits Osteoclast Differentiation by Suppression of NFATc1 Activity

Caldecrin/chymotrypsin C is a novel secretory-type serine protease that was originally isolated as a serum calcium-decreasing factor from the pancreas. Previously, we reported that caldecrin suppressed the bone-resorbing activity of rabbit mature osteoclasts (Tomomura, A., Yamada, H., Fujimoto, K., Inaba, A., and Katoh, S. (2001) FEBS Lett. 508, 454–458). Here, we investigated the effects of caldecrin on mouse osteoclast differentiation induced by macrophage-colony stimulating factor and the receptor activator of NF-κB ligand (RANKL) from the monocyte/macrophage cell lineage of bone marrow cells. Wild-type and protease-deficient mutant caldecrin dose-dependently inhibited RANKL-stimulated tartrate-resistant acid phosphatase-positive osteoclast formation from bone marrow cells. Caldecrin did not affect macrophage colony formation from monocyte/macrophage lineage cells or osteoclast progenitor generation in cultures of bone marrow cells. Caldecrin inhibited accumulation of the RANKL-stimulated nuclear factor of activated T-cells, cytoplasmic 1 (NFATc1) mRNA in bone marrow cells, which is a key transcription factor for the differentiation of osteoclasts. Caldecrin also suppressed RANKL-induced differentiation of the RAW264.7 monocyte/macrophage cell line into osteoclasts. Caldecrin reduced the transcriptional activity of NFATc1 in RAW264.7 cells, whereas those of NF-κB and c-Fos, which are also transcription factors involved in osteoclast differentiation, were unaffected. Caldecrin inhibited RANKL-stimulated nuclear translocation of NFATc1 and the activity of the calcium/calmodulin-dependent phosphatase, calcineurin. Caldecrin inhibited phospholipase Cγ1-mediated Ca2+ oscillation evoked by RANKL stimulation. RANKL-stimulated phosphorylation of spleen tyrosine kinase (Syk) was also attenuated by caldecrin. Taken together, these results indicate that caldecrin inhibits osteoclastogenesis, without its protease activity, by preventing a phospholipase Cγ1-mediated Ca2+oscillation-calcineurin-NFATc1 pathway.

Meckel's Cartilage: Discovery, Embryology and Evolution: —Overview of the Specificity of Meckel's Cartilage—

Abstract Meckels cartilage, discovered by German anatomist J. F. Meckel (1781–1833), is hyaline cartilage formed in the mandibular process of the first branchial arch of vertebrate embryos. An intermediate portion of Meckels cartilage is absorbed by multinucleated cells and disappears during the following developmental stages in mammals. The process of Meckels cartilage disappearance is not accompanied by the apoptosis of chondrocytes. The most posterior portion of the cartilage is changed to auditory ossicles by endochondral ossification, and the rest of the posterior portion transdifferentiates into sphenomandibular ligament. Meckels cartilage is not considered an anlage of the mandible, since bony tissue of the mandible is independently formed by membranous ossification. Chondrocytes are differentiated from mesodermal cells in general, whereas cells forming Meckels cartilage are differentiated from ectodermal mesenchymal cells of neural crest origin. In reptiles, Meckels cartilage ossifies and forms bone in the lower jaws, and cretaceous mammals had calcified Meckels cartilage in addition to a mandible. During the evolution from reptile to mammal, the mode of mastication changed, and the origin of bone in the lower jaw may have been gradually transferred from Meckels cartilage to the mandible.

Localization of Heat Shock Protein 27 (Hsp27) in the Rat Gingiva and its Changes with Tooth Eruption

Heat shock protein 27 kDa (Hsp27) functions as a molecular chaperon to prevent apoptosis as well as to contribute to the regulation of cell proliferation and differentiation during development. In the present study, the localization of Hsp27 in the oral epithelium of rats and its expression change during formation of the gingiva with the tooth eruption were examined immunohistochemically to elucidate the roles of Hsp27 in the oral mucosa. In adult rats, Hsp27-immunoreactivity was localized in the prickle and granular layers but absent in the basal and horny layers of the oral epithelium. On the other hand, in the outer and sulcular epithelia of the free gingival, Hsp27-immunoreactivity was detected in the whole layers, while it was not found in the proliferation zone of the junctional epithelium immunoreactive for Ki67. In immature rats on 10th postnatal day, Hsp27-immunoreactivity was intense in the prickle and granular layers of the oral epithelium, but was not detected in its basal layer. In rats at the eruptive phase on 15th postnatal day, Hsp27-immunoreactivity was detected in sites of the basal layer adjacent to where the dental cusps penetrated through the oral epithelium. Although the immunoreactivity for Ki67 was found in the basal layer of the oral epithelium, it was not localized in the Hsp27-immunopositive sites of tooth-penetration in the basal layer. Just after the tooth-eruption on 20th postnatal day, Hsp27-immunoreactivity was not found in the stratified squamous epithelium at the dentogingival junction, whereas it was intense in a single layer of cuboidal epithelial cells attached to the tooth neck. Ki67-positive cells were scattered in the stratified squamous epithelium at the dentogingival junction, whereas no positive cells were found in the portion of a single layer of cuboidal epithelial cells. These findings suggest that the outer and sulcular epithelia of the free gingiva have a relatively slower rate of proliferation than other gingival and oral epithelia, and that Hsp27 might inhibit the proliferation of the basal cells. Such specific phenomenon in the free gingiva occurred immediately after the dental cusps were exposed to the oral cavity.

Reproducibility of portable polysomnography values in children with habitual snoring

Abstract The purpose of this study was to examine the reproducibility of portable polysomnography for the evaluation of nocturnal sleep breathing in children with habitual snoring. Seven children and nine adults with habitual snoring were monitored at home during nocturnal sleep for three nights by parents or a bed-partner who had been informed about the use of portable polysomnography. Differences in adult polysomnographic values over the three nights were assessed by two-way ANOVA and Friedman test. The difference in polysomonographic values in children between two nights was assessed with an F-test and a Wilcoxon signed-ranks test. We found no differences in polysomnographic values among the three nights in adults. However, there were differences in Factor A (i.e. Mean SpO2, Lowest SpO2, Mean Apnea Duration and Mean Pulse Rate) among the adult subjects. In children, there was no difference in polysomnographic values between the two nights; however, there were differences in the variance of Mean SpO2 and Mean Apnea Duration between the two nights. In conclusion, to permit children to sleep as naturally as possible, sleep-screening tests can be performed reproducibly at home using portable polysomnography over a few days.

Costimulation of Murine Osteoblasts with Interferon-γ and Tumor Necrosis Factor-α Induces Apoptosis through Downregulation of Bcl-2 and Release of Cytochrome c from Mitochondria

During chronic inflammation from diseases, such as periodontal disease, the proinflammatory cytokines interferon-gamma (IFNγ) and tumor necrosis factor-α (TNFα) alter bone remodeling. To elucidate the underlying molecular mechanisms, we investigated the effect of IFNγ and TNFα on the proliferation and survival of clonal MC3T3-E1 mouse osteoblasts. We found that although IFNγ or TNFα alone affected cell growth and survival only marginally, costimulation with both synergistically inhibited cell growth and reduced cell viability. The diminished cell viability was due to apoptosis, as indicated by increased TUNEL staining and elevated caspase 3, 8, and 9 activities. Western blot also showed that costimulation with IFNγ and TNFα elicited cytochrome c release and downregulated B cell lymphoma 2 (Bcl-2) expression without affecting Bcl-2-associated X (Bax) protein expression. Furthermore, stable Bcl-2 overexpression significantly alleviated cell death following costimulation. Collectively, these results suggested that IFNγ and TNFα elicited osteoblast apoptosis via cytochrome c release from damaged mitochondria, caspase activation, and Bcl-2 downregulation.

A statistical analysis of outpatients in the Meikai University Hospital Clinic of Orthodontics during the past ten years

approximately one-half and one-third those of stainless steel wire and cobalt–chromium–nickel alloy wire, respectively. For a cyclic bending test, stainless steel wire, cobalt–chromium– nickel alloy wire, and beta-titanium alloy-2 wire did not fracture even after 10,000 times of bending cycles, although beta-titanium alloy-1 wire fractured after 4500 bending cycles. Orthodontic forces delivered by a quad helix made from both betatitanium alloy wires were lower than those for stainless steel wire and cobalt–chromium–nickel alloy wire.

Mechanical evaluation of upper molars intrusion using a orthodontic implant anchorage—Influences by difference of traction part

In this study, to minimize intervention to the enamel and prevent enamel fracture at debonding, all-inone adhesive was applied to the orthodontic bracket bonding system. FE-SEM observation of the enamel surface of human premolar conditioned with phosphoric acid or all-in-one adhesive was performed. The bracket was bonded to the conditioned enamel using 4-META/MMA-TBB resin or Bis-GMA resin. The shear bond strength of the bracket to the enamel was measured before and after 20,000 thermo-cycles. Thereafter, the fracture mode of fractured specimens was classified by Adhesive Remnant Index (ARI). Application of phosphoric acid resulted in the appearance of typical etching pattern attributed to alignment of the enamel prism. After thermo-cycle, the bond strength significantly decreased from 17–19 to 13 MPa and ARI changed from 1 to 0. However, application of all-in-one adhesive resulted in the appearance of only blank outline of the enamel prism. No reduction of bond strength before and after thermo-cycle (12– 13 MPa) was observed. After debonding, a part of all-in-one adhesive remained on the enamel surface. The bond strengths, before and after thermo-cycle, inall-in-oneadhesivegroup were close to those, after thermo-cycle, of the phosphoric acid group. Application of all-in-one adhesive to orthodontic bracket bonding allowed for reducing intervention to the enamel and preventing enamel fracture at debonding. DOI: 10.1016/j.odw.2010.11.010