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Biomedical subjects

Teruko Takano-Yamamoto

Publications and source records attributed to Teruko Takano-Yamamoto.

At least 19 recordsLinked to original sources
PubMed2007

Clinical use of miniscrew implants as orthodontic anchorage: success rates and postoperative discomfort.

INTRODUCTION: In this study, we evaluated the clinical usefulness of miniscrews as orthodontic anchorage. We examined their success rates, analyzed factors associated with their stability, and evaluated patients' postoperative pain and discomfort with a retrospective questionnaire. METHODS: Seventy-five patients, 116 titanium screws of 2 types, and 38 miniplates were retrospectively examined. Each patient was given a questionnaire that included a visual analog scale to indicate discomfort after implantation. RESULTS: The success rate for each type of implant was greater than 80%. The analysis of 79 miniscrews with a 1.3-mm diameter showed no significant correlations between success rate and these variables: age, sex, mandibular plane angle, anteroposterior jaw-base relationship, control of periodontitis, temporomandibular disorder symptoms, loading, and screw length. Most patients receiving titanium screws or miniplates with mucoperiosteal-flap surgery reported pain, but half of the patients receiving miniscrews without flap surgery did not report feeling pain at any time after placement. In addition, patients with miniscrews reported minimal discomfort due to swelling, speech difficulty, and difficulty in chewing. CONCLUSIONS: Miniscrews placed without flap surgery have high success rates with less pain and discomfort after surgery than miniscrews placed with flap surgery or miniplates placed with either procedure.

Adult↗
PubMed2006

The presence of ABCG2-dependent side population cells in human periodontal ligaments.

Periodontal ligament (PDL) is capable of regenerating several types of periodontal tissues. However, the stem cells in PDL have been less well characterized. Recently, it has been represented that stem cells have a potent ability to exclude Hoechst dye, and cells possessing this phenotype are termed "side population (SP)." In addition, it is suggested that the SP cells are ubiquitously present in adult tissues, therefore, we investigated the presence of SP cells in PDL. Hoechst dye efflux assay showed that PDL cells include 3.9% SP cells. This SP profile disappeared in the presence of verapamil or reserpine. Only ABCG2-expressing cells were detected in PDL cells by flow cytometric analysis. Furthermore, RT-PCR demonstrated that ABCG2 mRNA expression remarkably correlated with PDL SP phenotype. Our findings demonstrate that PDL contains ABCG2-dependent SP cells. Hence, it is possible that this population could contribute to periodontal tissue regeneration as PDL stem cells.

ATP Binding Cassette Transporter, Subfamily G, Mem↗
PubMed2006

Roles of PKC, PI3K and JNK in multiple transduction of CCN2/CTGF signals in chondrocytes.

CCN2/connective tissue growth factor (CCN2/CTGF) is known to promote both the proliferation and differentiation of chondrocytes, which actions are mediated by ERK and p38 MAPK, respectively. In this study, we first re-evaluated the involvement of multiple MAPKs therein and found that JNK also mediated such CCN2 signals. Thereafter, we further analyzed the roles of upstream kinases. The involvement of PKC, PI3K and PKA in the CCN2 signaling to promote the maturation, proliferation and terminal differentiation of a human chondrocytic cell line, HCS-2/8 and rabbit primary growth cartilage cells was investigated. As a result, the PKC inhibitor calphostin C repressed all of the effects of CCN2, which were represented by increased synthesis of DNA and proteoglycans and the display of alkaline phosphatase activity. In addition, evaluation of the effect of the PI3K inhibitor wortmannin disclosed the contribution of PI3K in transducing CCN2 signals to promote chondrocyte hypertrophy. This signal was known to be mediated by PKB, which was translocated into the nucleus upon CCN2 stimulation. Of note, calphostin C showed inhibitory effects on the activation of p38 MAPK, ERK and also PKB, whereas it exerted no effect on JNK activation. These results suggest that PKC is a driver of multiple signal transducing kinases that promote the proliferation and differentiation of chondrocytes. The requirement of PI3K in transmitting the signal for terminal differentiation and PKC-independent signaling pathways for the promotion of chondrocytic growth and differentiation, which was mediated by JNK, were also uncovered.

Animals↗
PubMed2006

AlphaVbeta3 integrin ligands enhance volume-sensitive calcium influx in mechanically stretched osteocytes.

We propose that specific osteocyte-matrix interactions regulate the volume-sensitive calcium influx pathway, which we have shown is mediated by stretch-activated cation channels (SA-Cat) and is essential for the stretch-activated anabolic response in bone. The current study measured the hypotonic swelling-induced increase in cytosolic calcium concentration, [Ca(2+)](i), in rat osteocytes, and found that cells adherent to different matrices behave differently. Osteopontin and vitronectin, matrix molecules that bind the alpha(V)beta(3) integrin, induced larger responses to the hypotonic swelling than other matrix molecules that bind other integrins. Addition of echistatin, which is a soluble alpha(V)beta(3) ligand, significantly enhanced the hypotonic [Ca(2+)](i) increase in addition to inducing an immediate increase in [Ca(2+)](i) by itself. These results strongly support the contention that alpha(V)beta(3) integrin signaling in osteocytes interacts with that in mechanotransduction, which is downstream of SA-Cat.

Animals↗
PubMed2006

Quantitative evaluation of cortical bone thickness with computed tomographic scanning for orthodontic implants.

INTRODUCTION: The purpose of this study was to quantitatively evaluate cortical bone thickness in various locations in the maxilla and the mandible. In addition, the distances from intercortical bone surface to root surface, and distances between the roots of premolars and molars were also measured to determine the acceptable length and diameter of the miniscrew for anchorage during orthodontic treatment. METHODS: Three-dimensional computed tomographic images were reconstructed for 10 patients. Cortical bone thicknesses were measured in the buccal and lingual regions mesial and distal to the first molar, distal to the second molar, and in the premaxillary region at 2 different levels. Differences in cortical bone thickness at 3 angles (30 degrees, 45 degrees, and 90 degrees) were also assessed. Distances of the intercortical bone surface to the root surface and the root proximity were also measured at the above areas. RESULTS: Significantly less cortical bone thickness was observed at the buccal region distal to the second molar compared with other areas in the maxilla. Significantly more cortical bone was observed on the lingual side of the second molar compared with the buccal side. In the mandible, mesial and distal to the second molar, significantly more cortical bone was observed compared with the maxilla. Furthermore, significantly more cortical bone was observed at the anterior nasal spine level than at Point A in the premaxillary region. Cortical bone thickness resulted in approximately 1.5 times as much at 30 degrees compared with 90 degrees Significantly more distance from the intercortical bone surface to the root surface was observed at the lingual region than at the buccal region mesial to the first molar. At the distal of the first mandibular molar, significantly more distance was observed compared to that in the mesial, and also compared with both distal and mesial in the maxillary first molar. There was significantly more distance in root proximity in the mesial area than in distal area at the first molar, and significantly more distance was observed at the occlusal level than at the apical level. CONCLUSIONS: These data show that the safest location for placing miniscrews might be mesial or distal to the first molar, and an acceptable size of the miniscrew is less than approximately 1.5 mm in diameter and approximately 6 to 8 mm in length.

Adult↗
PubMed2006

Skeletal anchorage for orthodontic correction of maxillary protrusion with adult periodontitis.

Because the number of adult patients seeking orthodontic treatment is increasing, orthodontists are becoming more likely to encounter patients with adult periodontitis. However, it is sometimes difficult to establish anchorage because of poor periodontal tissues in patients with adult periodontitis. This article reports the successful use of skeletal anchorage to treat a maxillary protrusion case complicated by severe adult periodontitis. A female patient aged 50 years seven months showed a skeletal Class II jaw base relationship. A spacing of five mm in the upper anterior teeth with an overjet of 7.5 mm and overbite of four mm was observed. She had generalized horizontal bone loss in both arches, with vertical bone loss in the posterior segment. After periodontal treatment, miniplates were placed in the zygomatic process, and retraction and intrusion of the maxillary incisors were performed. After active treatment for 21 months, the upper incisors had been inclined 9.5 degrees lingually, intruded two mm at the apex, and good anterior occlusion was achieved. Acceptable occlusion and periodontal tissue were maintained after a retention period of two years. Our results suggest that skeletal anchorage is useful for retraction and intrusion of upper incisors in cases of maxillary protrusion with severe adult periodontitis.

Female↗
PubMed2006

Fluid shear stress induces less calcium response in a single primary osteocyte than in a single osteoblast: implication of different focal adhesion formation.

UNLABELLED: The immediate calcium response to fluid shear stress was compared between osteocytes and osteoblasts on glass using real-time calcium imaging. The osteoblasts were responsive to fluid shear stress of up to 2.4 Pa, whereas the osteocytes were not. The difference in flow-induced calcium may be related to differences in focal adhesion formation. INTRODUCTION: To explore the immediate response to mechanical stress in a bone cell population, we examined flow-induced calcium transients. In addition, the involvement of focal adhesion-related calcium transients in response to fluid flow in the cells was studied. MATERIALS AND METHODS: Bone cells were isolated from 16-day-old embryonic chicken calvaria by serial treatment with EDTA and collagenase. Single cells on glass without intercellular connections were subjected to fluid flow, and intracellular calcium concentration was measured using imaging with fluo-3. The identification of cell populations in the same field was performed with a chick osteocyte-specific antibody, OB7.3, and an alkaline phosphatase substrate, ELF-97, for osteoblast identification afterward. Immunofluorescence staining of vinculin was performed to visualize focal adhesions. RESULTS: The percentage of cells responding to fluid shear stress at 1.2 Pa was 5.5% in osteocytes, 32.4% in osteoblasts, and 45.6% in OB7.3/ELF-97-negative cells. Furthermore, osteoblasts and OB7.3/ELF-97-negative cells were more responsive to 2.4 Pa than 1.2 Pa, whereas osteocytes were less responsive. The elevation of calcium transients over baseline did not show any significant differences in the populations. To elucidate the mechanism accounting for the fact that single osteocytes are less sensitive to fluid shear stress of up to 2.4 Pa than osteoblasts, we studied focal adhesion-related calcium transients. First, we compared focal adhesion formation between osteocytes and osteoblasts and found a larger number of focal adhesions in osteoblasts than in osteocytes. Next, when the cells were pretreated with GRGDS (0.5 mM) before flow treatment, a significant reduction of calcium transients in osteoblasts (18%) was observed, whereas calcium transients in osteocytes were not changed by GRGDS. Control peptide GRGES did not reduce the calcium transients in either cell type. Furthermore, we confirmed that osteoblasts in calvaria showed a marked formation of vinculin plaques in the periphery of the cells. However, osteocytes in calvaria showed faint vinculin plaques only at the base of the processes. CONCLUSIONS: On glass, single osteocytes are less sensitive to fluid shear stress up to 2.4 Pa than osteoblasts. The difference in calcium transients might be related to differences in focal adhesion formation. Shear stress of a higher magnitude or direct deformation may be responsible for the mechanical response of osteocytes in bone.

Animals↗
PubMed2005

Three-dimensional reconstruction of chick calvarial osteocytes and their cell processes using confocal microscopy.

Osteocytes are surrounded by hard bone matrix. Therefore, it has not previously been possible to demonstrate the real architecture of the osteocyte network in bone. We previously reported that it is possible to observe osteocytes in bone by labeling the cells with fluorescence and using confocal laser scanning (CLS) microscopy. In this study, we for the first time conducted an extensive analysis of the morphology and morphometry of the three-dimensional (3D) osteocyte structure using three-dimensionally reconstructed fluorescent images. Sixteen-day-old embryonic chick calvariae were stained with fluorescently labeled phalloidin and observed using a confocal laser scanning microscope. Morphometry of osteocytes in the calvaria was analyzed using extensive three-dimensional reconstructing software IMARIS, process length measuring software NEURON TRACER and cell surface area-/cell volume-analyzing software SURPASS. From the IMARIS-derived images, we found that the average of 10 osteocytes is 52.7 +/- 5.7 processes, and the point-to-point distance between centers of the osteocytes was 24.1 +/- 2.8 microm. In addition, we could calculate that each osteocyte spans an average of 4180 +/- 673 microm3 of bone volume. NEURON TRACER showed that the length of osteocyte processes was 0.26 +/- 0.02 microm per 1 microm3 bone compartment. In addition, SURPASS indicated that the surface area of osteocytes was 0.36 +/- 0.03 microm2 per 1 microm3 bone compartment and that the volume ratio of osteocyte cell body to bone compartment was 9.42% +/- 1.18%. Together, the average total length of the processes, the average surface area, and the average volume of one osteocyte were 1070 +/- 145 microm, 1509 +/- 113 microm2, and 394 +/- 49 microm3, respectively. It is possible to reconstruct the real architecture of the osteocyte network and obtain morphometric data from fluorescently labeled osteocytes in chick calvaria.

Animals↗
PubMed2005

Experimental tooth movement upregulates preproenkephalin mRNA in the rat trigeminal nucleus caudalis and oralis.

Levels of preproenkephalin mRNA expression in trigeminal subnucleus complex by noxious tooth movement stimuli were examined using in situ hybridization. At 24 h, preproenkephalin mRNA expression was significantly upregulated in the ipsilateral trigeminal subnucleus caudalis (P<0.05), and in the subnucleus oralis (P<0.05). These findings suggested that enkephalinergic inhibitory systems could be activated during tooth movement, and that subnucleus oralis may be involved in modulation of the nociception, as well as the subnucleus caudalis.

Afferent Pathways↗
PubMed2005

Clinical assessment of orthodontic outcomes with the peer assessment rating, discrepancy index, objective grading system, and comprehensive clinical assessment.

PURPOSE: The purpose of this study was to quantitatively assess orthodontic treatment outcomes in postgraduate orthodontic clinics at Okayama University (OU) and Indiana University (IU). MATERIAL: Using the peer assessment rating (PAR) index, the discrepancy index (DI), the American Board of Orthodontist's objective grading system (OGS), and the comprehensive clinical assessment (CCA), we evaluated pretreatment and posttreatment records of 72 patients from OU and 54 patients from IU. RESULTS: The average pretreatment PAR score with United Kingdom weighting was 32 for OU subjects and 28 for IU subjects. Differences in maxillary and mandibular buccal alignment between schools were statistically significant ( P < .01). The posttreatment PAR scores were 7 for OU and 4 for IU. The difference in overjet between schools was statistically significant ( P < .05). The mean DI scores were 19 for OU and 17 for IU. OU patients scored significantly more DI points for crowding and mandibular plane angle compared with IU patients ( P < .05). On the other hand, they lost significantly fewer DI points for overbite and occlusion compared with IU patients ( P < .05). The mean OGS scores were 34 for OU and 33 for IU. Buccolingual inclination and overjet scores were significantly higher in OU patients compared with IU ( P < .05). The mean CCA score was approximately 4 points for both OU and IU. CONCLUSIONS: These data suggest that these indexes are useful for comparing treatment outcomes between clinics. They were able to identify specific problems in treating Asian patients.

Adolescent↗
PubMed2005

Skeletal Class III oligodontia patient treated with titanium screw anchorage and orthognathic surgery.

This article reports the successful treatment of a patient, aged 15 years 8 months, with a Class III malocclusion and oligodontia; a titanium screw was used for absolute anchorage during treatment. The patient had a concave profile because of mandibular excess and asymmetric spaces in both arches. Titanium screws were implanted in the retromolar area during intraoral vertical ramus osteotomy combined with LeFort I osteotomy. Absolute anchorage was provided with anchorage wires extending from the screws to the left canine and the right lateral incisor. After orthodontic space closure, the mandibular molars were moved mesially without lingual tipping of the mandibular incisors. A good interincisal relationship was achieved. Our results suggest that titanium screws and anchorage wires in the retromolar area are useful for the mesial movement of mandibular molars.

Adolescent↗
PubMed2005

Maxillary distraction osteogenesis to treat maxillary hypoplasia: comparison of an internal and an external system.

BACKGROUND: Distraction osteogenesis (DO) has become a mainstream surgical technique for patients with jaw deformities. In cases of maxillary hypoplasia, DO with a rigid external distraction (RED) system has been used for maxillary advancement; however, DO with internal devices is currently popular. MATERIALS: This article describes DO with an internal device and a RED system in 2 patients with maxillary hypoplasia with oligodontia. The first patient, a young girl, had a concave profile due to maxillary hypoplasia and 9 congenitally missing permanent teeth. At age 11 years 11 months, she received DO with an internal device. The second patient, a boy aged 11 years 7 months, was treated with DO with a RED system. RESULTS: In the girl, the maxilla was advanced 5.0 mm without any dentoalveolar compensation. In the boy, the maxilla was advanced 7.0 mm, but undesirable mesial movement of posterior teeth was observed. CONCLUSIONS: DO with internal devices is simpler and more useful than the RED system for maxillary hypoplasia with oligodontia.

Anodontia↗
PubMed2005

Orthodontic treatment of a patient with an impacted maxillary second premolar and odontogenic keratocyst in the maxillary sinus.

An eight-year-, four-month-old girl was brought to the orthodontic clinic of Okayama University Medical and Dental Hospital. The patient had an impacted upper left second premolar because of an odontogenic keratocyst and showed a skeletal Class II jaw base relationship. At the age of six years four months, marsupialization of a cyst was performed at the Okayama University Medical and Dental Hospital because the patient had shown a swelling of the left cheek because of the cyst. The upper left second premolar was located in the roof of the maxillary sinus. The cyst was histopathologically diagnosed as an odontogenic keratocyst. At the age of nine years 10 months and after regaining the space for eruption of the premolar, the impacted premolar erupted without traction. At the age of 12 years five months, edgewise treatment was initiated, which continued for three years. After removing the edgewise appliance, an optimum occlusion was achieved. The occlusion was maintained without recurrence of the keratocyst after a retention period of five years.

Bicuspid↗
PubMed2005

Early orthodontic treatment and long-term observation in a patient with Morquio syndrome.

Early orthodontic treatment and long-term observation in a patient with Morquio syndrome were demonstrated. To date, there are no case reports describing orthodontic treatment in such a patient. The patient showed spaced maxillary and mandibular arches with a tongue thrust habit at age seven years eight months. She also showed a protruded upper lip, labial inclination of the upper and lower anterior teeth, and thin enamel. The tongue thrust habit disappeared after the application of a removable orthodontic appliance. The spaced dentition in the upper and lower arches improved after treatment with a fixed appliance with closing loop arch wire (0.017 x 0.025") and bands on the upper and lower molars. We did not use an edgewise appliance because of the thin enamel. The protruded upper lip and labial inclination of the upper and lower anterior teeth were also improved after treatment, but optimal intercuspation of the teeth was not achieved. However, optimal intercuspation of the teeth was achieved after long-term observation and the masticatory function was improved. It was suggested that early orthodontic treatment could improve the malocclusion in a patient with Morquio syndrome and that improvement of masticatory function could be achieved during a long-term retention period.

Age Factors↗
PubMed2005

Bone morphogenetic protein 3 expression pattern in rat condylar cartilage, femoral cartilage and mandibular fracture callus.

Mandibular condylar cartilage differs from primary cartilage in morphological organization of the chondrocytes and in responses to biomechanical stress and humoral factors. For the first time, we describe the expression of Bmp3 mRNA in relation to types I, II and X collagen mRNA (as determined by in situ hybridization) in chondrocytes of the rat mandibular condylar cartilage, femoral articular cartilage, femoral growth plate cartilage, and temporal cartilage, which transiently appeared in the reparative response stage of mandibular ramus fracture healing. In all cartilages evaluated, Bmp3 was expressed in proliferating chondrocytes that expressed type I collagen in condylar cartilage, articular cartilage, and temporal cartilage appearing during fracture healing. Bmp3 was also found in hypertrophic chondrocytes that expressed type X collagen mRNA in all cartilages evaluated. Furthermore, in remodeling bone, Bmp3 mRNA was strongly expressed in active osteoblast cells in periosteal reaction layers formed after fracture. These findings suggest that Bmp3 expression in a special layer of typical articular cartilage may be regulated by mechanical stress stimulation. We also found that Bmp3 was expressed in the periosteal layers of the bone segments near the fracture site during fracture healing.

Animals↗
PubMed2004

Possible roles of Runx1 and Sox9 in incipient intramembranous ossification.

UNLABELLED: We evaluated the detailed expression patterns of Runx1 and Sox9 in various types of bone formation, and determined whether Runx1 expression was affected by Runx2 deficiency and Runx2 expression by Runx1 deficiency. Our results indicate that both Runx1 and Sox9 are intensely expressed in the future osteogenic cell compartment and in cartilage. The pattern of Runx1 and Sox9 expression suggests that both genes could potentially be involved in incipient intramembranous bone formation during craniofacial development. INTRODUCTION: Runx1, a gene essential for hematopoiesis, contains RUNX binding sites in its promoter region, suggesting possible cross-regulation with Runx2 and potential regulatory roles in bone development. On the other hand, Sox9 is essential for chondrogenesis, and haploinsufficiency of Sox9 leads to premature ossification of the skeletal system. In this study, we studied the possible roles of Runx1 and Sox9 in bone development. MATERIALS AND METHODS: Runx1, Runx2/Osf2, and Sox9 expression was evaluated by in situ hybridization in the growing craniofacial bones of embryonic day (E)12-16 mice and in the endochondral bone-forming regions of embryonic and postnatal long bones. In addition, we evaluated Runx2/Osf2 expression in the growing face of Runx1 knockout mice at E12.5 and Runx1 expression in Runx2 knockout mice at E14.5. RESULTS: Runx1 and Sox9 were expressed in cartilage, and the regions of expression expanded to the neighboring Runx2-expressing osteogenic regions. Expression of both Runx1 and Sox9 was markedly downregulated on ossification. Runx1 and Sox9 expression was absent in the regions of endochondral bone formation and in actively modeling or remodeling bone tissues in the long bones as well as in ossified craniofacial bones. Runx2 expression was not affected by gene disruption of Runx1, whereas the expression domains of Runx1 were extended in Runx2(-/-) mice compared with wildtype mice. CONCLUSIONS: Runx1 and Sox9 are specifically expressed in the osteogenic cell compartments in the craniofacial bones and the bone collar of long bones, and this expression is downregulated on terminal differentiation of osteoblasts. Our results suggest that Runx1 may play a role in incipient intramembranous bone formation.

Animals↗
PubMed2004

Terminal differentiation of osteoblasts to osteocytes is accompanied by dramatic changes in the distribution of actin-binding proteins.

UNLABELLED: Immunofluorescence staining of actin-binding proteins in osteoblasts and osteocytes was performed. alpha-Actinin, myosin, and tropomyosin showed similar organization in both osteoblastic stress fibers and osteocyte processes. However, fimbrin, villin, filamin, and spectrin showed dramatic differences in distribution between osteoblasts and osteocytes. This study suggested that terminal differentiation of osteoblasts to osteocytes is accompanied by highly dramatic changes in the distribution of actin-binding proteins. INTRODUCTION: We previously reported that osteocyte shape is dependent on actin filaments. To analyze the terminal differentiation from osteoblasts to osteocytes, we investigated the actin-binding proteins, which are the control elements in the dynamic organization of the actin cytoskeleton. MATERIALS AND METHODS: We used primary chick osteocytes and osteoblasts, the phenotypes of which were confirmed by use of OB7.3, a chick osteocyte-specific monoclonal antibody and by detection of alkaline phosphatase activity, respectively. Immunofluorescence staining was performed for visualizing actin-binding proteins. Furthermore, we applied shear stress at 12 dyns/cm2 to the cells and compared the changes in fimbrin distribution. RESULTS: Immunofluorescence staining of fimbrin and alpha-actinin showed their presence in the processes of osteocytes, with especially strong signals of fimbrin at the sites of divarication of the processes. Anti-villin was reactive with the osteocyte cytoplasm but not with the processes. Interestingly, anti-villin immunoreactivity was much stronger in osteocytes than in osteoblasts. Filamin was localized along the stress fibers of osteoblasts but was seen only in those in the proximal base of osteocyte processes. Myosin and tropomyosin were found to have a similar pattern in both stress fibers of osteoblasts and osteocyte processes. The difference in the distribution of anti-spectrin staining was highly dramatic. Osteoblasts immunostained with anti-spectrin showed punctate signals on their cytoplasmic membranes, whereas anti-spectrin in osteocytes detected a filamentous organization; and the spectrin was totally colocalized with actin from the distal portion of the cytoplasmic processes to the cell center. In osteoblasts, shear stress induced recruitment of fimbrin to the end of stress fibers. However, fimbrin in the osteocyte processes did not change its localization. CONCLUSION: We found that terminal differentiation of osteoblasts to osteocytes was accompanied by highly dramatic changes in the distribution of actin-binding proteins, changes of which may affect cellular function.

Actinin↗