Glyburide inhibits the bone resorption induced by traumatic occlusion in rats.

OBJECTIVE: To examine whether glyburide inhibits bone destruction caused by traumatic occlusion in a rat occlusal trauma model. BACKGROUND: Excessive mechanical stress, such as traumatic occlusion, induces expression of IL-1ß and may be involved in bone resorption. NLRP3 inflammasomes have been linked to IL-1ß expression, but it is currently unclear whether glyburide, the inhibiter of NLRP3 inflammasome, suppresses occlusal trauma in rats. METHODS: Male SD rats aged 7 weeks were used. In the trauma group, the occlusal surface of the maxillary first right molar was raised by attaching a metal wire to apply occlusal trauma to the mandibular first right molar. In the trauma + glyburide group, the NLRP3 inhibitor glyburide was administered orally every 24 hours from 1 day before induction of occlusal trauma. Rats were euthanized after 5 or 10 days, and the maxillary first molars were harvested with the adjacent tissues for histopathological investigation. Immunohistochemical expression of IL-1ß, NLRP3, and RANKL was also assessed. RESULTS: On day 5, bone resorption was significantly greater in the trauma group compared with the control group or the trauma + glyburide group, and there were significantly higher numbers of osteoclasts and cells positive for IL-1ß, NLRP3, and RANKL in the trauma group. CONCLUSION: In this study, glyburide inhibits bone resorption by traumatic occlusion in rats. It suggests that the NLRP3/IL-1ß pathway might be associated with bone resorption induced by traumatic occlusion.

Toll-like receptor 2 activation primes and upregulates osteoclastogenesis via lox-1.

BACKGROUND: Lectin-like oxidized low-density-lipoprotein receptor 1 (Lox-1) is the receptor for oxidized low-density lipoprotein (oxLDL), a mediator in dyslipidemia. Toll-like receptor (TLR)-2 and - 4 are receptors of lipopolysaccharide (LPS) from Porphyromonas gingivalis, a major pathogen of chronic periodontitis. Although some reports have demonstrated that periodontitis has an adverse effect on dyslipidemia, little is clear that the mechanism is explained the effects of dyslipidemia on osteoclastogenesis. We have hypothesized that osteoclast oxLDL has directly effect on osteoclasts (OCs), and therefore alveolar bone loss on periodontitis may be increased by dyslipidemia. The present study aimed to elucidate the effect of Lox-1 on osteoclastogenesis associated with TLRs in vitro. METHODS: Mouse bone marrow cells (BMCs) were stimulated with macrophage colony-stimulating factor into bone marrow macrophages (BMMs). The cells were also stimulated with synthetic ligands for TLR2 (Pam3CSK4) or TLR4 (Lipid A), with or without receptor activator of nuclear factor kappa-B ligand (RANKL), and assessed for osteoclastogenesis by tartrate-resistant acid phosphatase (TRAP) staining, immunostaining, western blotting, flow activated cell sorting (FACS) analysis, real-time polymerase chain reaction (PCR), and reverse transcription PCR. RESULTS: Lox-1 expression was significantly upregulated by Pam3CSK4 and Lipid A in BMCs (p < 0.05), but not in BMMs. FACS analysis identified that Pam3CSK4 upregulated RANK and Lox-1 expression in BMCs. TRAP-positive cells were not increased by stimulation with Pam3CSK4 alone, but were increased by stimulation with combination combined Pam3CSK and oxLDL. Expression of both Lox-1 and myeloid differentiation factor 88 (MyD88), an essential adaptor protein in the TLR signaling pathway, were suppressed by inhibitors of TLR2, TLR4 and mitogen-activated protein kinase (MAPK). CONCLUSIONS: This study supports that osteoclastogenesis is promoted under the coexistence of oxLDL by TLR2-induced upregulation of Lox-1 in BMCs. This indicates that periodontitis could worsen with progression of dyslipidemia.

Efficacy of an Electric Toothbrush With Monitor in Dental Plaque Removal: A Crossover Randomized Controlled Trial.

BACKGROUND AND PURPOSE: Plaque control is very important in the treatment of periodontitis. However, plaque is difficult to remove because one cannot see one's own oral cavity. The purpose of this study was to verify the plaque removal effect of a prototype device that has a built-in image sensor in the head of an electric toothbrush, enabling the user to brush while checking the condition of the tooth surface on a monitor in real time and to assess their sense of use. MATERIALS AND METHODS: The subjects were 10 fifth-year students from the Graduate School of Dental Science, Fukuoka Dental College, Fukuoka, Japan. The subjects were divided into those who used electric toothbrushes while having the condition of the tooth surface checked with a monitor (monitor group) and those without a monitor (non-monitor group). O'Leary plaque control records before and after brushing and the brushing time were measured, and questionnaires were given to the subjects after brushing. Scaling and professional tooth cleaning were performed after completing the questionnaire. One week later, subjects were switched to the opposite group and had the same measurements and questionnaires. The Wilcoxon signed-rank test was used to compare both groups before and after the examination at a 5% significance level. RESULTS: The monitor group had significantly better plaque removal than the non-monitor group. In addition, the monitor group spent significantly more time brushing than the control group. CONCLUSION: Brushing while monitoring oral conditions in real time using an electric toothbrush with a built-in image sensor showed that significantly better plaque removal can be achieved with a longer brushing time.

Stabilization of MAPO1 by specific binding with folliculin and AMP-activated protein kinase in O6-methylguanine-induced apoptosis.

When DNA is damaged by alkylating agents, apoptosis is induced to exclude cells carrying DNA lesions in order to prevent mutations and cancer. MAPO1, identified as a component involved in the induction of apoptosis, interacts with AMP-activated protein kinase (AMPK) and folliculin (FLCN). We herein report that MAPO1 is stabilized during the course of apoptosis, triggered by alkylation-induced O(6)-methylguanine in DNA. An immunoblotting analysis revealed that the amount of MAPO1 increased gradually after treatment with N-methyl-N-nitrosourea (MNU), although the level of mRNA for MAPO1 was unchanged. When cells were exposed to a proteasome inhibitor, MG132, the MAPO1 level significantly increased. On the other hand, application of a protein synthesis inhibitor, cycloheximide, caused a decrease in the MAPO1 content, implying that proteasome-mediated degradation is involved. In FLCN-knockdown cells, the MAPO1 level decreased, and no increases occurred even after MNU treatment. In contrast, stabilization of MAPO1 occurred in AMPKα-knockdown cells even without MNU treatment. While MAPO1 retains its ability to stably bind to FLCN, it dissociates gradually from AMPK after exposure to MNU. It seems that the proapoptotic function of MAPO1 may be regulated by AMPK and FLCN through stabilization of MAPO1 itself.

DNA/protamine complex paste for an injectable dental material.

A DNA/protamine complex powder was prepared by reaction between DNA and protamine sulfate solution with stirring in order to develop a new injectable biomaterials for dental therapy. The powder of DNA/protamine complex became paste by kneading the complex powder and distilled water. Complex formation was confirmed by FT-IR measurement. The complex paste had a porous structure and its viscosity was approximately 280.1 Pas. The paste could easily pass through a needle of 0.25 mm internal diameter. It seemed that DNA/protamine complex paste has suitable viscosity for clinical use as an injectable biomaterial. Although, the complex paste delayed the growth speed of Staphylococcus aureus, Pseudomonas aeruginosa, Porphyromonas gingivalis and Prevotella intermedia for limited periods, it cannot kill and inhibit growing bacteria. The complex paste disk showed a mild tissue response and gradually degraded after the implantation into the soft tissue of rats. These results suggested that this DNA/protamine complex paste could be a useful material for a biodegradable biomaterial. In particular, this paste will be applicable as an injectable biomaterial using syringe for the repair of defects of living tissue, GBR treatment and/or GTR treatment in dentistry.

A multicenter prospective cohort study on the effect of smoking cessation on periodontal therapies in Japan.

Few prospective studies have reported the effects of periodontal therapy on patients who attempted to quit smoking. This study aimed to assess how smoking cessation affects periodontal therapy. Twenty-five smokers with periodontitis were investigated by dividing them into two groups, a smoking cessation support group and a continued smoking group. Those in the support group received counseling and nicotine replacement therapy, followed by periodontal treatment conducted by dentists who had completed an e-learning course on smoking cessation. Clinical parameters were measured at baseline, 3, and 6 months. Most clinical parameters improved for those in the smoking cessation support group. There were no significant improvements in bleeding on probing (BOP) or the number of severe periodontal disease sites in the continued smoking group. Probing pocket depth (PPD) and clinical attachment levels (CAL) at sites that received scaling and root planing (SRP) significantly improved in all subjects. BOP did not improve at reevaluation in the smoking relapse subgroup. Patients in the smoking cessation support program led by dental professionals showed more improvement in BOP than those in the continued smoking group.

Individual architecture of subgingival microflora in chronic periodontitis.

BACKGROUND: Nearly 400 species of bacteria have been found in human periodontal pockets, and half of them remain uncultured to date. The diagnosis of individual periodontal microflora using culture-independent detection of species is expected to serve as a tool for 'tailor-made' periodontal treatments. However, the richness and abundance of bacterial species within individual subgingival microflora have not been sufficiently studied to develop more specific diagnostic microbiological tests. The purpose of this study was to determine the ecological architecture of the subgingival microflora among chronic periodontitis patients and their individual differences based on phylotype analyses. METHODS: Four 16S rRNA gene libraries were constructed from subgingival plaque samples taken from all diseased sites in four chronic periodontitis patients. The 480 clones generated from each of the four libraries were analyzed by phylotyping and subjected to ecological estimation of species richness. RESULTS: The indices of species richness of the four libraries were 73, 75, 98 or 100 phylotypes. A total of 195 phylotypes were identified in the combined libraries. The majority of phylotypes were assigned to the Bacteroidetes, Fusobacteria, Proteobacteria, Firmicutes and Actinobacteria phyla. The phylotypes assigned to the Bacteroidetes and Fusobacteria phyla were the most predominant in each library (chi2-test, p < 0.05). CONCLUSIONS: In this study, the molecular ecology of 1920 clones obtained from four patients' subgingival plaque samples was examined. More than half of the detected clones were categorized under either the Bacteroidetes or the Fusobacteria phyla. Each library showed unique richness and abundance of phylotypes.

Prevalence and risk factors for peri-implant diseases in Japanese adult dental patients.

We investigated the prevalences and risk factors for peri-implant diseases in Japanese adult dental patients attending a follow-up visit at dental hospitals or clinics as part of their maintenance program. This cross-sectional multicenter study enrolled patients with dental implants who attended regular check-ups as part of a periodontal maintenance program during the period from October 2012 through September 2013. Patients with implants with at least 3 years of loading time were included in the study. The condition of peri-implant tissue was examined and classified into the following categories: healthy, peri-implant mucositis, and peri-implantitis. Patients were also evaluated for implant risk factors. A total of 267 patients (110 men, 157 women; mean age: 62.5 ± 10.7 years) were analyzed. The prevalence of patient-based peri-implant mucositis was 33.3% (n = 89), and the prevalence of peri-implantitis was 9.7% (n = 26). Poor oral hygiene and a history of periodontitis were strong risk factors for peri-implant disease. The present prevalences were lower than those previously reported. The quality of periodontal therapy before and after implant installation and patient compliance and motivation, as indicated by plaque control level, appear to be important in maintaining peri-implant tissue health.

Differentiation of Apical Bud Cells in a Newly Developed Apical Bud Transplantation Model Using GFP Transgenic Mice as Donor.

Rodent mandibular incisors have a unique anatomical structure that allows teeth to grow throughout the lifetime of the rodent. This report presents a novel transplantation technique for studying the apical bud differentiation of rodent mandibular incisors. Incisal apical end tissue with green fluorescent protein from transgenic mouse was transplanted to wild type mice, and the development of the transplanted cells were immunohistologically observed for 12 weeks after the transplantation. Results indicate that the green fluorescent apical end tissue replaced the original tissue, and cells from the apical bud differentiated and extended toward the incisal edge direction. The immunostaining with podoplanin also showed that the characteristics of the green fluorescent tissue were identical to those of the original. The green fluorescent cells were only found in the labial side of the incisor up to 4 weeks. After 12 weeks, however, they were also found in the lingual side. Here the green fluorescent cementocyte-like cells were only present in the cementum close to the dentin surface. This study suggests that some of the cells that form the cellular cementum come from the apical tissue including the apical bud in rodent incisors.

Randomized Placebo-Controlled and Controlled Non-Inferiority Phase III Trials Comparing Trafermin, a Recombinant Human Fibroblast Growth Factor 2, and Enamel Matrix Derivative in Periodontal Regeneration in Intrabony Defects.

We investigated the efficacy, safety, and clinical significance of trafermin, a recombinant human fibroblast growth factor (rhFGF)-2, for periodontal regeneration in intrabony defects in Phase III trials. Study A, a multicenter, randomized, double-blind, placebo-controlled study, was conducted at 24 centers. Patients with periodontitis with 4-mm and 3-mm or deeper probing pocket depth and intrabony defects, respectively, were included. A total of 328 patients were randomly assigned (2:1) to receive 0.3% rhFGF-2 or placebo, and 323 patients received the assigned investigational drug during flap surgery. One of the co-primary endpoints, the percentage of bone fill at 36 weeks after drug administration, was significantly greater in the rhFGF-2 group at 37.131% (95% confidence interval [CI], 32.7502 to 41.5123; n = 208) than it was in the placebo group at 21.579% (95% CI, 16.3571 to 26.8011; n = 100; p < 0.001). The other endpoint, the clinical attachment level regained at 36 weeks, was not significantly different between groups. Study B, a multicenter, randomized, blinded (patients and evaluators of radiographs), and active-controlled study was conducted at 15 centers to clarify the clinical significance of rhFGF-2. Patients with 6-mm and 4-mm or deeper probing pocket depth and intrabony defects, respectively, were included. A total of 274 patients were randomly assigned (5:5:2) to receive rhFGF-2, enamel matrix derivative (EMD), or flap surgery alone. A total of 267 patients received the assigned treatment during flap surgery. The primary endpoint, the linear alveolar bone growth at 36 weeks, was 1.927 mm (95% CI, 1.6615 to 2.1920; n = 108) in the rhFGF-2 group and 1.359 mm (95% CI, 1.0683 to 1.6495; n = 109) in the EMD group, showing non-inferiority (a prespecified margin of 0.3 mm) and superiority of rhFGF-2 to EMD. Safety problems were not identified in either study. Therefore, trafermin is an effective and safe treatment for periodontal regeneration in intrabony defect, and its efficacy was superior in rhFGF-2 compared to EMD treatments.

NF-κB-regulated transcriptional control of CLCA in a differentiated mouse keratinocyte line.

BACKGROUND: CLCA was postulated to be a calcium-activated chloride channel accessory protein. Recent reports indicate that CLCA isoforms are likely to be expressed in different layers of the stratified epithelium of the skin. OBJECTIVE: The present study investigated the transcriptional mechanism by which murine CLCA2 (mCLCA2) is expressed in the transformed keratinocyte line Pam212 that can differentiate. METHODS: A luciferase reporter assay, chromatin immunoprecipitation (ChIP) assay, reverse transcription-PCR, and immunocytochemistry were performed using Pam212 cells. RESULTS: Promoter activity of mCLCA2 was inhibited profoundly by site-directed mutagenesis of a putative nuclear factor-κB (NF-κB) binding site and by treatment with siRNA against p65. ChIP and transcription factor assays showed the specific association of endogenously activated p65 protein with the NF-κB binding domain. As confirmed by the nuclear translocation of p65, tumor necrosis factor α and caffeic acid phenethyl ester (CAPE) increased and decreased mCLCA2 promoter activity, respectively, but exhibited modest effects on endogenous mCLCA2 expression in cells in culture medium containing 0.05 mM Ca(2+). When the Ca(2+) concentration was raised to 1.0mM, the mRNA and protein levels of mCLCA2 increased as well as those of the differentiation markers keratin 1 (K1) and K10. CAPE profoundly suppressed only the Ca(2+)-triggered expression of mCLCA2, not K1 or K10. Immunohistochemistry of native skin and organotypic 3D cultures confirmed the distribution of the CLCA2 homolog in differentiated cells. CONCLUSION: The present study revealed for the first time that basal NF-κB activity is involved in the Ca(2+)-dependent regulation of mCLCA2 expression in a mouse keratinocyte line.

Comparison of fracture sites and post lengths in longitudinal root fractures.

INTRODUCTION: Comparing the epidemiology of fractures originating in the cervical and apical regions may help to understand the causes and risk of a vertical root fracture. We aimed to determine the frequency of vertical root fractures in different fracture sites and how the fracture site relates to fracture direction and post length. METHODS: Teeth diagnosed with a vertical root fracture were retrospectively surveyed for age and sex of the patient, type of tooth, a fracture region in the longitudinal axial direction, site of the fracture, and presence of a post. The fracture region in the longitudinal axial direction was classified as an incomplete fracture, complete fracture, and uncertain. Incomplete fractures were further classified into a fracture originating in the cervical region, a fracture originating in the midregion, and a fracture originating in the apical region. Posts were evaluated by loss of post and length of post. RESULTS: Fractures originating in the cervical and apical region occurred around the same frequency, whereas fractures originating in the midregion were extremely scarce. Of the fractures originating in the cervical region, 36.2% were in a mesial and/or distal site and 57.4% in a buccal and/or lingual site. Of the fractures originating in the apical region, 90.8% were in the buccal and/or lingual site. The number of cases of fractures originating in the apical region decreased with increased post length. CONCLUSIONS: Sites of fracture and post length differed greatly between fractures originating in the cervical region and the apical region, suggesting that risk factors for fractures originating in the cervical and apical regions are different.

Combination of Root Surface Modification with BMP-2 and Collagen Hydrogel Scaffold Implantation for Periodontal Healing in Beagle Dogs.

UNLABELLED: Objective : Biomodification of the root surface plays a major role in periodontal wound healing. Root surface modification with bone morphogenetic protein (BMP) stimulates bone and cementum-like tissue formation; however, severe ankylosis is simultaneously observed. Bio-safe collagen hydrogel scaffolds may therefore be useful for supplying periodontal ligament cells and preventing ankylosis. We examined the effects of BMP modification in conjunction with collagen hydrogel scaffold implantation on periodontal wound healing in dogs. MATERIAL AND METHODS: The collagen hydrogel scaffold was composed of type I collagen sponge and collagen hydrogel. One-wall infrabony defects (5 mm in depth, 3 mm in width) were surgically created in six beagle dogs. In the BMP/Col group, BMP-2 was applied to the root surface (loading dose; 1 µg/µl), and the defects were filled with collagen hydrogel scaffold. In the BMP or Col group, BMP-2 coating or scaffold implantation was performed. Histometric parameters were evaluated at 4 weeks after surgery. RESULTS: Single use of BMP stimulated formation of alveolar bone and ankylosis. In contrast, the BMP/Col group frequently enhanced reconstruction of periodontal attachment including cementum-like tissue, periodontal ligament and alveolar bone. The amount of new periodontal ligament in the BMP/Col group was significantly greater when compared to all other groups. In addition, ankylosis was rarely observed in the BMP/Col group. CONCLUSION: The combination method using root surface modification with BMP and collagen hydrogel scaffold implantation facilitated the reestablishment of periodontal attachment. BMP-related ankylosis was suppressed by implantation of collagen hydrogel.

Continuous fever-range heat stress induces thermotolerance in odontoblast-lineage cells.

OBJECTIVE: Heat shock during restorative procedures can trigger damage to the pulpodentin complex. While severe heat shock has toxic effects, fever-range heat stress exerts beneficial effects on several cells and tissues. In this study, we examined whether continuous fever-range heat stress (CFHS) has beneficial effects on thermotolerance in the rat clonal dental pulp cell line with odontoblastic properties, KN-3. METHODS: KN-3 cells were cultured at 41°C for various periods, and the expression level of several proteins was assessed by Western blot analysis. After pre-heat-treatment at 41°C for various periods, KN-3 cells were exposed to lethal severe heat shock (LSHS) at 49°C for 10min, and cell viability was examined using the MTS assay. Additionally, the expression level of odontoblast differentiation makers in surviving cells was examined by Western blot analysis. RESULTS: CFHS increased the expression levels of several heat shock proteins (HSPs) in KN-3 cells, and induced transient cell cycle arrest. KN-3 cells, not pre-heated or exposed to CFHS for 1 or 3h, died after exposure to LSHS. In contrast, KN-3 cells exposed to CFHS for 12h were transiently lower on day 1, but increased on day 3 after LSHS. The surviving cells expressed odontoblast differentiation markers, dentine sialoprotein and dentine matrix protein-1. These results suggest that CFHS for 12h improves tolerance to LSHS by inducing HSPs expression and cell cycle arrest in KN-3 cells. CONCLUSIONS: The appropriate pretreatment with continuous fever-range heat stress can provide protection against lethal heat shock in KN-3 cells.

Cell viabilities and biodegradation rates of DNA/protamine complexes with two different molecular weights of DNA.

Two types of DNA/protamine complexes were prepared from protamine sulfate and 7000 base pair (bp) DNA or original DNA to investigate the effect of the molecular weight of DNA on zeta potential, cell viability, flowability, soft tissue response, and biodegradation rate. The 7000 bp DNA/protamine complex had a negative charge while the original DNA/protamine complex had a positive charge. The cell viabilities (90.4-106.8%) of these complexes were close to each other. The 7000 bp DNA/protamine complex became a softer dough than that of the original DNA/complex when both were kneaded with water. In vivo, the original DNA/protamine complex showed a milder tissue response. The original DNA/protamine complex almost disappeared 30 days after implantation. The 7000 bp DNA/complex disappeared approximately 2 weeks after implantation and areas where samples were implanted became empty. Thereafter, the empty space was gradually replaced by new soft tissues. The original DNA/protamine complex showed low intercalation and groove binding ratios of daunorubicin hydrochloride. Results indicate that high DNA condensation by cationic protamine protected the penetration of degradation enzymes into these complexes. It was found that a high molecular weight of DNA reduced the biodegradation rate and flowability. This study suggests that DNA/protamine complexes could be candidates for biomaterials that control biodegradation rates and flowability.

A novel inhibitory mechanism of nitrogen-containing bisphosphonate on the activity of Cl- extrusion in osteoclasts.

Nitrogen-containing bisphosphonates have been well known to be inhibited farnesyl diphosphate synthase (FDPS), an enzyme in mevalonic acid metabolism, resulting in disturbance in polymerization of cytoskeleton structure in bone resorption and promotion of apoptosis in mature osteoclasts. Although bisphosphonates have been reported to activate ion transporters in native epithelium and Xenopus oocytes, little is known whether bisphosphonates affect acid hydrochronic acid extrusion in osteoclasts during bone resorption. The aim of this study was to determine the role of bisphosphonates on inhibition of hydrochronic acid extrusion in osteoclasts. Effects of zoledronic acid, a nitrogen-containing bisphosphonate, on the Cl(-) current activated by extracellular acidification were examined in two types of osteoclasts derived from RAW264.7 cells and mouse bone marrow macrophages (BMMs). Extracellular acidification induced outwardly rectifying Cl(-) currents in mouse osteoclasts. Zoledronic acid dose-dependently inhibited the acid-activated Cl(-) current. The non-nitrogen bisphosphonate etidronic acid had no effect on the acid-activated Cl(-) current. Tetracycline-induced FDPS silencing caused a significant decrease in the Cl(-) current. The inhibitor of geranylgeranyl transferase suppressed the Cl(-) current. By contrast, the inhibitory action of zoledronic acid was rescued by addition of geranylgeranyl acid, a derivative of mevalonic acid. The activity of acid-activated Cl(-) currents was dependent on expression of ClC-7 during osteoclastogenesis. These results suggest that nitrogen-containing bisphosphonates suppress the activity of osteoclastic acid-activated Cl(-) currents through FDPS inhibition, suggesting the inhibition of Cl(-) extrusion activity.

Activation of AMP-activated protein kinase by MAPO1 and FLCN induces apoptosis triggered by alkylated base mismatch in DNA.

O6-methylguanine produced in DNA by the action of simple alkylating agents, such as N-methyl-N-nitrosourea (MNU), causes base-mispairing during DNA replication, thus leading to mutations and cancer. To prevent such outcomes, the cells carrying O6-methylguanine undergo apoptosis in a mismatch repair protein-dependent manner. We previously identified MAPO1 as one of the components required for the induction of apoptosis triggered by O6-methylguanine. MAPO1, also known as FNIP2 and FNIPL, forms a complex with AMP-activated protein kinase (AMPK) and folliculin (FLCN), which is encoded by the BHD tumor suppressor gene. We describe here the involvement of the AMPK-MAPO1-FLCN complex in the signaling pathway of apoptosis induced by O6-methylguanine. By the introduction of siRNAs specific for these genes, the transition of cells to a population with sub-G1 DNA content following MNU treatment was significantly suppressed. After MNU exposure, phosphorylation of AMPKα occurred in an MLH1-dependent manner, and this activation of AMPK was not observed in cells in which the expression of either the Mapo1 or the Flcn gene was downregulated. When cells were treated with AICA-ribose (AICAR), a specific activator of AMPK, activation of AMPK was also observed in a MAPO1- and FLCN-dependent manner, thus leading to cell death which was accompanied by the depolarization of the mitochondrial membrane, a hallmark of the apoptosis induction. It is therefore likely that MAPO1, in its association with FLCN, may regulate the activation of AMPK to control the induction of apoptosis triggered by O6-methylguanine.

Antibodies against ClC7 inhibit extracellular acidification-induced Cl⁻ currents and bone resorption activity in mouse osteoclasts.

The Cl⁻ channel/transporter ClC7 is crucial for osteoclastic bone resorption and might become a therapeutic target for osteoporosis. In this study, we raised anti-ClC7 polyclonal antibodies against three different peptide sequences, including G215, P249, and R286, which are the mutation regions found in autosomal dominant osteopetrosis type II patients and examined the effects of these antibodies on the ClC7 Cl⁻ current induced by extracellular acidification (acid-activated Cl⁻ current) using the whole-cell patch clamp technique and bone resorption activity in mouse osteoclasts. Intracellular dialysis of osteoclasts with antibodies to intracellular G215 (Ab-G215) and extracellular application of antibodies to extracellular P249 (Ab-P249) or R286 (Ab-R286) inhibited the acid-activated Cl⁻ current. These antibodies also suppressed the acid-activated Cl⁻ current in ClC7 overexpressing Raw264.7 cells; however, Cl⁻ currents evoked by hypotonic stimulation and the inherent inwardly rectifying K+ currents in mouse osteoclasts were unaffected by these antibodies. Furthermore, extracellularly applied Ab-P249 and Ab-R286 also reduced bone resorption activity. Our results demonstrate that these antibodies specifically block ClC7 in mouse osteoclasts. Thus, anti-ClC7 antibodies have potential promise for treatment of osteoporosis.

Development of a portable bruxism monitoring and analysis device equipped with a microcomputer and its practical application.

The purposes of this study were to develop and verify the a portable nocturnal bruxism monitoring and analysis device equipped with a microcomputer, and to clinically apply the device to know the actual conditions of bruxism patients. EEPROM was installed in the device for the data recording, and after the data collection, the recorded data was entered into a personal computer via serial port. After confirming the accuracy of the device, a total of 30 subjects were enrolled in this study to monitor their bruxism activities for 3 nights. Bruxism self-aware group consisted of 14 subjects, 7 males and 7 females, and unaware group consisted of 16 patients, 8 males and 8 females. Most of the subjects reported that the new device was easy to handle. The average bruxism time per hour and the average bruxism lasting time were 223.8 +/- 112.0 and 3.9 +/- 2.9 s in the self-aware group, and 49.3 +/- 38.3 and 0.8 +/- 0.7 s in the unaware group, respectively. The bruxism self-aware group showed statistically longer average bruxism time per hour and the average bruxism lasting time. It was confirmed that the new bruxism monitoring and analysis device is practical for clinical application to monitor and analyze the electromyographic activities.