Biomedical subjects

Kenji Takada

Publications and source records attributed to Kenji Takada.

17 recordsLinked to original sources

PubMed2003

Induction of osteoclast differentiation by Runx2 through receptor activator of nuclear factor-kappa B ligand (RANKL) and osteoprotegerin regulation and partial rescue of osteoclastogenesis in Runx2-/- mice by RANKL transgene.

Receptor activator of nuclear factor-kappaB ligand (RANKL), osteoprotegerin (OPG), and macrophage-colony stimulating factor play essential roles in the regulation of osteoclastogenesis. Runx2-deficient (Runx2-/-) mice showed a complete lack of bone formation because of maturational arrest of osteoblasts and disturbed chondrocyte maturation. Further, osteoclasts were absent in these mice, in which OPG and macrophage-colony stimulating factor were normally expressed, but RANKL expression was severely diminished. We investigated the function of Runx2 in osteoclast differentiation. A Runx2-/- calvaria-derived cell line (CA120-4), which expressed OPG strongly but RANKL barely, severely suppressed osteoclast differentiation from normal bone marrow cells in co-cultures. Adenoviral introduction of Runx2 into CA120-4 cells induced RANKL expression, suppressed OPG expression, and restored osteoclast differentiation from normal bone marrow cells, whereas the addition of OPG abolished the osteoclast differentiation induced by Runx2. Addition of soluble RANKL (sRANKL) also restored osteoclast differentiation in co-cultures. Forced expression of sRANKL in Runx2-/- livers increased the number and size of osteoclast-like cells around calcified cartilage, although vascular invasion into the cartilage was superficial because of incomplete osteoclast differentiation. These findings indicate that Runx2 promotes osteoclast differentiation by inducing RANKL and inhibiting OPG. As the introduction of sRANKL was insufficient for osteoclast differentiation in Runx2-/- mice, however, our findings also suggest that additional factor(s) or matrix protein(s), which are induced in terminally differentiated chondrocytes or osteoblasts by Runx2, are required for osteoclastogenesis in early skeletal development.

Animals↗

PubMed2003

Volume and shape of masticatory muscles in patients with hemifacial microsomia.

OBJECTIVE: To test the following hypotheses in hemifacial microsomia (HFM): (1) the volumes of the masseter, lateral and medial pterygoid, and temporal muscles are reduced on the affected versus unaffected side; (2) significant differences exist between the degrees of right-left disproportion in these four masticatory muscles; (3) circumferential shapes of the masticatory muscles are more irregular on the affected versus unaffected side; and (4) the degree of masticatory muscle right-left disproportion can be judged by the degree of ear, mandibular, or dental anomalies. SUBJECTS AND METHODS: Ten preadolescent patients with HFM were studied using facial photographs, dental casts, cephalometric and panoramic radiographs, and helical computed tomography scanning and three-dimensional reconstruction technique. Volumes of masseter, lateral and medial pterygoid, and temporal muscles on both sides were measured. Muscle volume disproportion was expressed as the affected/unaffected ratio. Muscle circumferential irregularity was expressed as the ratio between the total circumferential length and corresponding cross-sectional area. RESULTS: Masticatory muscle volumes were significantly smaller on the affected versus unaffected side. No significant differences were observed between the degrees of disproportion of the four masticatory muscles examined. Circumferential shapes of masticatory muscles were significantly more irregular on the affected versus unaffected side. There were no significant relationships of the degree of ear, mandibular, or dental anomalies in relation to masticatory muscle disproportion. CONCLUSIONS: In HFM the masseter, lateral and medial pterygoid, and temporal muscles all have a significantly smaller volume on the affected versus unaffected side, and specific muscles were not severely affected in the present subjects. Furthermore, all four muscles showed a significantly more irregular shape on the affected versus unaffected side. Finally, the severity of masticatory muscle disproportion can probably not be judged by the degree of ear, mandibular, and dental anomalies in preadolescent patients with HFM.

Adolescent↗

PubMed2003

Report of a patient with hypoglossia-hypodactylia syndrome and a review of the literature.

OBJECTIVE: To present the morphology of the extremities, craniofacial structures, and the oral cavity based on roentgencephalometry and three-dimensional computed tomography and magnetic resonance imaging scanning in a patient with hypoglossia-hypodactylia syndrome, discuss the orthodontic treatment method, and review the literature for the syndrome. PATIENT: The patient was a 6-year-old boy diagnosed with hypoglossia-hypodactylia syndrome at birth. He had hypodactylia as well as micrognathia with steep inclination of the anterior surface of the mandible in relation to the lower mandibular plane. He had missing mandibular incisors with concomitant bone defect limited to the associated alveolar ridge and an absence of any malformations in the mandibular ramus and condylar head. The patient had a bilateral scissors bite with an extremely constricted mandibular dental arch, skeletal Class II jaw relationship with an average mandibular plane angle and maxillary incisors inclined palatally. He had extremely reduced tongue size and hypertrophy of the floor of the mouth. Anomalies of the central nervous system were not observed. There was no evidence of hearing loss.

Cephalometry↗

PubMed2003

Rigid external distraction osteogenesis for a patient with maxillary hypoplasia and oligodontia.

OBJECTIVE: In this report, the orthodontic treatment combined with rigid external distraction osteogenesis in a 5.5-year-old girl with midfacial hypoplasia and oligodontia is described. PATIENT: The child presented with a reduced maxilla, protruding lower lip, skeletal Class III jaw relationship with a low mandibular plane angle, a short and flattened nose, anterior crossbite, and aplasia of 16 permanent teeth. The patient was treated with rigid external maxillary distraction osteogenesis, maxillary protraction headgear, and Class III elastics. Following treatment, the maxilla was displaced in a forward direction with new bone formation at the tuberosities and the mandible rotated backward in relation to the anterior cranial base. The anterior crossbite was corrected, and the skeletal jaw relationship changed from a Class III to a Class I skeletal pattern. The soft tissue facial profile showed that the nasal projection had been increased, the nasolabial angle increased, and the lower lip protrusion was reduced. Postoperative treatment results were acceptable. CONCLUSION: This report documents that early maxillary advancement with rigid external osteogenesis offers a promising treatment alternative for a very young patient with maxillary hypoplasia and oligodontia.

Anodontia↗

PubMed2003

Mandibular distraction osteogenesis using an intraoral device and bite plate for a case of hemifacial microsomia.

OBJECTIVE: To present orthodontic treatment combined with mandibular distraction osteogenesis using an intraoral device and a bite plate in a patient with hemifacial microsomia, severe facial asymmetry, and unilateral mandibular hypoplasia. PATIENT: An 8-year-old girl exhibited mandibular deviation resulting from hypoplasia of the mandibular condyle and ramus on the left side. The patient was treated with an intraoral device for mandibular distraction osteogenesis, bite plate, and hybrid-type functional appliance. Facial asymmetry was improved, and the mandibular ramus was elongated in an anterior and primarily posterior direction with slightly posterior and superior displacement of the proximal segment. Postdistraction treatment results have been stable for 1 year. At the 1-year follow-up, the volume of the lateral and medial pterygoid muscles on the left side had increased. The condyle and disc on the right temporomandibular joint moved well and in harmony at open mouth position, and a rotational movement of the left temporomandibular joint was observed.

Cephalometry↗

PubMed2003

Craniofacial morphology in a patient with Simpson-Golabi-Behmel syndrome.

OBJECTIVE: We present the case of a 6-year-old boy with a coarse face, cleft palate, and malocclusion with anterior open bite who had been diagnosed with Simpson-Golabi-Behmel syndrome. Morphology of the craniofacial structures was examined on the basis of conventional radiographs, three-dimensional (3D) computed tomography (CT) and magnetic resonance (MR) scanning. PATIENT: This patient had 13 ribs on the right side, slight scoliosis, supernumerary nipples, a coarse face, hypertelorism, a short broad upturned nose, a wide mouth, a straight facial profile with incompetence of the lips, midline groove of tongue, and cleft palate. The patient also had severe anterior open bite, a distal step-type molar relationship, five congenitally missing teeth, and a supernumerary tooth. Lateral cephalometric analysis revealed a large anterior cranial base, a large maxilla and mandible, a large inferior face height, and skeletal Class I jaw relationship with a high mandibular plane angle and large gonial angle. The 3D CT image showed a large cranium, a long face height, and prominent skull sutures. The MR image showed a large tongue, midline groove of the tongue, and a small space between tongue and palate.

Abnormalities, Multiple↗

PubMed2003

Three-dimensional evaluation of a rare case with multiple impacted teeth using CT.

A 15-year-old patient is presented with 11 impacted teeth including 2 supernumerary teeth, who did not exhibit hereditary or clinical disease. The patient showed the extruded and lingually inclined lower incisors, the anteriorly inclined palatal plane, extremely large curve of Spee, and crowding in the bone. A detailed description of the positional relationship between each impacted tooth and the neighboring tooth was given using the 3D CT-image.

Adolescent↗

PubMed2003

Electron paramagnetic resonance imaging of nitric oxide organ distribution in lipopolysuccaride treated mice.

The recent development of electron paramagnetic resonance (EPR) permits its application for in vivo studies of nitric oxide (NO). In this study, we tried to obtain 3D EPR images of endogenous NO in the abdominal organs of lipopolysuccaride (LPS) treated mice. Male ICR mice, each weighing about 30 g, received 10 mg/kg of LPS intraperitoneally. Six hours later, a spin trapping reagent comprised of iron and an N-dithiocarboxy sarcosine complex (Fe(DTCS)2, Fe 200 mM, DTCS/Fe = 3) were injected subcutaneously. Two hours after this treatment, the mice were fixed in a plastic holder and set in the EPR system, equipped with a loop-gap resonator and a 1 GHz microwave. NO was detected as an NO-Fe(DTCS)2 complex, which had a characteristic 3-line EPR spectrum. NO-Fe(DTCS)2 complexes in organ homogenates were also measured using a conventional X-band EPR system. NO-Fe(DTCS)2 spectra were obtained in the upper abdominal area of LPS treated mice at 8 h after the LPS injection. 3D EPR tiled and stereoscopic images of the NO distribution in the hepatic and renal areas were obtained at the same time. The NO-Fe(DTCS)2 distribution in abdominal organs was confirmed in each organ homogenate using conventional X-band EPR. This is the first known EPR image of NO in live mice kidneys.

Animals↗

PubMed2003

Association of ecNOS gene polymorphisms with end stage renal diseases.

Nitric oxide (NO) is a very potent regulator of intrarenal hemodynamics and is thought to be an important factor in the deterioration of renal function. Several polymorphisms of the endothelial NO synthase (eNOS) gene have been reported. For instance, tandem 27-bp repeats in intron 4 of the eNOS gene are polymorphic, i.e. eNOS4a allele has 4 and eNOS4b has 5 tandem repeats, and the association between eNOS4a and myocardial infarction has been reported. In addition, a missense Glu298Asp mutation in exon 7 of the eNOS gene is reported to be a risk factor for hypertension or myocardial infarction. In this study, we investigated the frequencies of these 2 polymorphisms of eNOS gene in patients with end-stage renal diseases (ESRD), and compared them with those of healthy subjects. Genomic DNA was obtained from regularly hemodialyzed patients and healthy volunteers. The allele frequencies of eNOS4a and eNOS4b in intron 4 were analyzed by PCR and the missense Glu298Asp mutation in exon 7 were determined by PCR FMLP analysis. The allele frequency of eNOS4a (eNOS4a/b and eNOS4a/a) in non-diabetic group is significantly higher than that in healthy controls (27.3% vs. 19.0%, p = 0.01) though there is no significant difference between diabetic group and healthy controls. On the other hand, the frequencies of missense Glu298Asp mutation in both non-diabetic and diabetic groups are significantly higher than that in healthy controls (22.5% in non-diabetic, 20.8% in diabetic and 7.4% in control group, p = 0.002: non-diabetic vs. control, p = 0.01: diabetic vs. control). This study clarified that the polymorphisms in intron 4 and exon 7 of eNOS gene are the genetic risk factors for ESRD. The polymorphisms in intron may change the transcriptional activity and those in exon may alter the 3 dimensional structure of the enzyme, and may affect the progression of renal diseases via decreased NO synthesis. Further study is required to clarify the detailed mechanisms.

Adult↗

PubMed2002

Core-binding factor beta interacts with Runx2 and is required for skeletal development.

Core-binding factor beta (CBFbeta, also called polyomavirus enhancer binding protein 2beta (PEBP2B)) is associated with an inversion of chromosome 16 and is associated with acute myeloid leukemia in humans. CBFbeta forms a heterodimer with RUNX1 (runt-related transcription factor 1), which has a DNA binding domain homologous to the pair-rule protein runt in Drosophila melanogaster. Both RUNX1 and CBFbeta are essential for hematopoiesis. Haploinsufficiency of another runt-related protein, RUNX2 (also called CBFA1), causes cleidocranial dysplasia in humans and is essential in skeletal development by regulating osteoblast differentiation and chondrocyte maturation. Mice deficient in Cbfb (Cbfb(-/-)) die at midgestation, so the function of Cbfbeta in skeletal development has yet to be ascertained. To investigate this issue, we rescued hematopoiesis of Cbfb(-/-) mice by introducing Cbfb using the Gata1 promoter. The rescued Cbfb(-/-) mice recapitulated fetal liver hematopoiesis in erythroid and megakaryocytic lineages and survived until birth, but showed severely delayed bone formation. Although mesenchymal cells differentiated into immature osteoblasts, intramembranous bones were poorly formed. The maturation of chondrocytes into hypertrophic cells was markedly delayed, and no endochondral bones were formed. Electrophoretic mobility shift assays and reporter assays showed that Cbfbeta was necessary for the efficient DNA binding of Runx2 and for Runx2-dependent transcriptional activation. These findings indicate that Cbfbeta is required for the function of Runx2 in skeletal development.

Animals↗

PubMed2002

Facial asymmetry in subjects with skeletal Class III deformity.

We investigated the frequency, site, amount, and direction of facial asymmetry in human adults with mandibular prognathism and examined if these characteristics were associated postnatally with cardinal clinical signs that may indicate a predisposition to facial asymmetry. Two hundred twenty young Japanese adults (69 men and 151 women) who exhibited skeletal Class III malocclusions were selected. The sample was divided into a Postnatal Factor Group and a Nonpostnatal Factor Group. The former group included those who had: (1) received orthodontic treatment using a chin cap; (2) exhibited clinical symptoms of temporomandibular joint (TMJ) disorder; (3) reported a history of maxillofacial trauma; or (4) radiographic abnormality of the condyles. Subjects with a deviation of more than 2 mm from the facial midline associated with any of the 4 landmarks (ANS, U1, L1 and Me) were classified as asymmetric and the asymmetry was measured on a postero-anterior (P-A) cephalogram. Radiographic facial asymmetry was found frequently (70%-85%, for Menton), and most obviously in the lower jaw (P < .05). Lateral displacement toward the left side of the face occurred more often than right-sided deviation (P < .001, for Menton). However, the Postnatal Factor Group showed a higher proportion of subjects with lateral deviation toward the right side (P = .0031) and a greater amount (P < .0001) of chin deviation. This was due to the fact that the subjects having TMJ problems as a postnatal factor showed no directional uniqueness in jaw deviation and exhibited a longer distance of deviation.

Adolescent↗

PubMed2002

Three-dimensional magnetic resonance image of the mandible and masticatory muscles in a case of juvenile chronic arthritis treated with the Herbst appliance.

The present report documents, in a case of juvenile chronic arthritis (JCA) with mandibular retrognathia, three-dimensional (3D) changes in the mandible and the relationship between the mandible and the masticatory muscles resulting from treatment with the Herbst appliance after cessation of growth. Magnetic resonance scanning of the whole head was carried out before and after treatment. The mandible, the masseter, and the medial and lateral pterygoid muscles were segmented bilaterally and reconstructed in 3D for both stages. Superimposition of the datasets was carried out according to anatomical structures in the brain (cranial base). Mandibular superimposition was performed according to the mandibular symphysis and the lower mandibular border. The mandible moved forward and downward relative to the anterior cranial base. In addition, bone apposition was observed at the superior and posterior surfaces of both mandibular condyles and at the roof of the glenoid fossa. The masticatory muscles remained relatively stable in position in relation to the anterior cranial base. To our knowledge, such information in JCA patients has not previously been published in the literature. Using magnetic resonance imaging (MRI), it was possible to gain improved insight into the 3D morphology including soft tissues without the overlap of the surrounding tissues observed in the conventional radiographs. Accordingly, it is suggested that 3D magnetic resonance analysis is a more useful method for the follow-up of the JCA patients than radiographic techniques.

Adolescent↗

PubMed2002

Patterning of human dental arch wire blanks using a vector quantization algorithm.

We objectively and automatically classified arch wire blank forms represented by a series of facial surface points on tooth crowns in human adults with normal occlusions using a vector quantization algorithm on the basis of the generalized Lloyd algorithm. We investigated also the descriptive dental arch form parameters that were most effective in distinguishing the classified groups of dental arch wire blanks and examined if they were associated with specific anatomical traits. Dental casts, taken from 79 adults with complete dentitions, were laser scanned with a computer-assisted stereotaxic device. Coordinates of the tooth crown points (FA points) were measured for each dental arch expressed as a vector having positional elements in a series of 14 FA points and categorized into several codes (ie, patterns) according to the similarity of the quantized vector patterns. We found that classifying the dental arches into four patterns maximized the difference between arch wire blank patterns. The classified patterns were differentiated by a gradual broadening of the interarch widths posterior to the lateral incisor. The code with the narrowest arch had the longest coronal arch, whereas the code with the widest arch had the shortest coronal arch (P < .01). The interpremolar and intermolar basal arch widths determined for the code showing the widest arch were significantly greater than those for the code with the narrowest width (P < .01).

Adult↗

PubMed2002

The difference in condylar position between centric relation and centric occlusion in pretreatment Japanese orthodontic patients.

This study investigates the differences in condylar position between centric relation (CR) and centric occlusion (CO) in Japanese orthodontic patients before treatment. We employed 150 consecutive cases (age range: 6-57 years) for the study. Dental casts were mounted on a Panadent articulator with a power centric CR bite record. The differences in condylar position between CR and CO in all three spatial planes were measured using the Panadent Condyle Position Indicator (CPI). The subjects were divided into groups by age, gender, mandibular plane angle or angle classification. No significant differences in the magnitude of CPI measurements were found among the groups. The three-dimensional distances of condylar displacement on both sides were almost identical, and the superoinferior displacement (S-I) was greater (P < .0001) than the anteroposterior displacement (A-P). The S-I was greater (P = .02) on the left side than on the right side, while the A-P displacement was smaller (P < .0001) on the left side than that on the right side. Significant condylar displacement (2.0 mm for S-I and A-P, 0.5 mm for the lateral displacement, L) was found frequently in L (31.3%), S-I, and A-P, in that order. Fifty-eight (38.7%) of the subjects had significant displacement in L, S-I, or A-P. Moreover, Angle Class III subjects tended to have significant condylar displacement toward the left side. The results suggest that orthodontists should be aware of a high incidence of condylar displacement in Japanese orthodontic patients and measure condylar displacement before the start of comprehensive orthodontic treatment to unmask real jaw relationships and avoid possible misdiagnoses.

Adolescent↗

PubMed2002

Maxillary expansion and protraction in correction of midface retrusion in a complete unilateral cleft lip and palate patient.

A 7-year-old girl with a cleft lip and palate had a midface retrusion due to growth inhibition of the maxillary complex. She presented for correction of a severe total crossbite with a Class III skeletal pattern. Initially, maxillary expansion was provided to widen the maxilla and then maxillary protraction headgear was worn to improve the sagittal skeletal relation. Fixed orthodontic appliances were placed to align the dentition and Class III elastics were used to establish intercuspation and stability. The maxillary expansion and protraction usually provide effective improvement in skeletal Class III patients with repaired cleft lip and palate patients. The success of the orthopedic procedure essentially depends on the individual growth of the maxilla and the mandible. This case report shows the significant growth of the mandible after maxillary expansion and protraction in late adolescence.

Activator Appliances↗

PubMed2002

Fuzzy modelling for selecting headgear types.

The purpose of this study was to develop a computer-assisted inference model for selecting appropriate types of headgear appliance for orthodontic patients and to investigate its clinical versatility as a decision-making aid for inexperienced clinicians. Fuzzy rule bases were created for degrees of overjet, overbite, and mandibular plane angle variables, respectively, according to subjective criteria based on the clinical experience and knowledge of the authors. The rules were then transformed into membership functions and the geometric mean aggregation was performed to develop the inference model. The resultant fuzzy logic was then tested on 85 cases in which the patients had been diagnosed as requiring headgear appliances. Eight experienced orthodontists judged each of the cases, and decided if they 'agreed', 'accepted', or 'disagreed' with the recommendations of the computer system. Intra-examiner agreements were investigated using repeated judgements of a set of 30 orthodontic cases and the kappa statistic. All of the examiners exceeded a kappa score of 0.7, allowing them to participate in the test run of the validity of the proposed inference model. The examiners' agreement with the system's recommendations was evaluated statistically. The average satisfaction rate of the examiners was 95.6 per cent and, for 83 out of the 85 cases, 97.6 per cent. The majority of the examiners (i.e. six or more out of the eight) were satisfied with the recommendations of the system. Thus, the usefulness of the proposed inference logic was confirmed.

Adolescent↗

PubMed2002

A stent fabricated on a selectively colored stereolithographic model for placement of orthodontic mini-implants.

The purpose of this report is to present a new method for placing orthodontic mini-implants using a stent fabricated on a selectively colored stereolithographic model. A stent was fabricated that incorporated a guide groove drilled in accordance with the planned direction of the mini-implant. Tooth crowns, gingiva, tooth roots, and the maxillary sinuses were clearly identified in the stereolithographic model. As a result, the stent could be fabricated while taking into account the anatomic characteristics of both the bone interior and the dental surface. A stent fabricated on the selectively colored stereolithographic model is suggested to be a promising device for guiding placement of orthodontic mini-implants adjacent to the tooth roots and the maxillary sinuses.

Color↗