PubMed Health⌕ Search

Biomedical subjects

Kenji Takada

Publications and source records attributed to Kenji Takada.

At least 19 recordsLinked to original sources
PubMed2006

Reliability and sensitivity of jerk-cost measurement for evaluating irregularity of chewing jaw movements.

Rate of change in movement acceleration (jerk) is a universally accepted quantity to evaluate irregularities of human limb and eye movements. This study was aimed to attest reliability of the jerk measurement of masticatory jaw movements and to identify its sensitivity to discriminate between movements performed with the presence of varied occlusal interference. Jaw movements during gum chewing were recorded with a 3D tracking device. Twelve adult subjects participated in the experiments. For five subjects, normalized jerk-costs (NJC) during jaw closing were compared between those measured on two separate occasions. For seven subjects, the NJCs during closing were compared with those measured with/without introduction of four different types of occlusal interference. The NJCs did not differ significantly between the two recording occasions. The interference at the canine tooth induced greater increase in the NJCs than that at the molar tooth. The comparison between repeated measures revealed reproducibility of the NJCs. In addition, the NJC was shown to be capable of discriminating between irregularities of the movements induced by occlusal interference at the canine and molar tooth sites. These findings suggest that the NJC is a valid indicator of masticatory jaw movement irregularity induced by disturbances of full intercuspation between upper and lower teeth.

Adult↗
PubMed2006

Dual segmental distraction osteogenesis of the midface in a patient with Apert syndrome.

OBJECTIVE: To present orthodontic treatment combined with dual segmental distraction osteogenesis in a patient with Apert syndrome. PATIENT: A 15-year-old boy exhibited severe midfacial hypoplasia with retruded and hypoplastic maxilla and anterior open bite. The patient was treated with a rigid external distraction II system for distraction osteogenesis, a preadjusted edgewise appliance, and a modified maxillary protraction headgear. The concave profile with midfacial hypoplasia was improved. A tight occlusal relationship between maxillary and mandibular teeth was achieved. Postoperative treatment results have been stable for 1 year.

Acrocephalosyndactylia↗
PubMed2005

Model-based analysis of jaw-movement kinematics using jerk-optimal criterion: simulation of human chewing cycles.

Large intra- and/or inter-individual variability in human masticatory motor behaviors may reduce objectivity in assessing normality/abnormality for jaw movements. Analytical simulation by kinematic modeling based on a universally accepted objective criterion is a potentially useful clinical tool for credible diagnostic quantification of jaw motion. This study aimed to test whether a minimum-jerk (maximum-smoothness) model could accurately simulate the kinematics in each separate gum-chewing cycle of 10 healthy adults, and if so, to examine whether simulation errors reflected an extent of abnormality for chewing movements for 10 patients caused by temporomandibular joint disorders (TMD). The model predicted the lower incisor-point movements of the control group with reasonable accuracy. Overall, the prediction errors for the patients group were greater than the control group, demonstrating that prediction errors for jaw opening velocity were sensitive to the criteria for joint disorders. It was concluded that the present simulation emerged as being capable of scaling the not so smooth masticatory jaw movements performed in the presence of TMD.

Adult↗
PubMed2005

A mini-implant for orthodontic anchorage in a deep overbite case.

This article describes the orthodontic treatment of a 19-year-old female patient with anterior crowding. There was a moderate arch length discrepancy in the lower dental arch, a significant deep overbite, and a "gummy smile." We inserted an orthodontic mini-implant as anchorage for the intrusion of the upper incisor segment, followed by alignment of the upper and lower dental arches with an edgewise appliance without tooth extraction. The overbite was corrected from +7.2 mm to +1.7 mm by upper incisor intrusion, and the gummy smile was improved. Good occlusion and facial esthetics were achieved, and these results have been maintained for two years after completion of the active treatment.

Adult↗
PubMed2005

Transient portomesenteric venous gas in long-term hemodialysis patients.

We report on transient portomesenteric venous gas in two long-term hemodialysis patients who showed relatively benign and transient courses. These cases suggested that portomesenteric venous gas associated with long-term hemodialysis is not a predictor of mortality. Therefore, this condition should be carefully followed through clinical findings and the results of laboratory examinations. On the other hand, frequent followed-up computed tomography (CT) is considered unnecessary if serious gastrointestinal complications such as bowel necrosis are not suspected at initial CT examination.

Abdominal Pain↗
PubMed2004

In vivo imaging of oxidative stress in ischemia-reperfusion renal injury using electron paramagnetic resonance.

Oxidative stress during ischemia-reperfusion acute renal failure (IR-ARF) was noninvasively evaluated with in vivo electron paramagnetic resonance (EPR) imaging. Female ICR mice underwent left nephrectomy and 30-min ischemia-reperfusion of the right kidney. Oxidative stress was evaluated as organ reducing activity with the half-lives of the spin probe 3-carbamoyl-2,2,5,5-tetramethylpyrrolidine-1-oxyl (carbamoyl-PROXYL) using 1) conventional L-band EPR, which showed organ-reducing activity in the whole abdominal area; and 2) EPR imaging, which showed semiquantitative but organ-specific reducing activity. The results were compared with the reducing activity of organ homogenate and phosphatidylcholine hydroperoxide (PC-OOH) concentrations. Half-lives of carbamoyl-PROXYL in the whole upper abdominal area, measured by L-band EPR, were prolonged on day 3 after ischemia-reperfusion and recovered to the level of nontreated mice on day 7. This trend resembled closely that of serum creatinine and blood urea nitrogen concentration. The EPR imaging-measured carbamoyl-PROXYL half-life was also prolonged on day 3 in both the kidney and the liver. However, in the kidney this showed only partial recovery on day 7. In the liver, this convalescence was more remarkable. The ex vivo studies of organ reducing activity and PC-OOH agreed with the results from EPRI, but not with those from L-band EPR. These results indicate that renal reducing activity shows only partial recovery on day 7 after ischemia-reperfusion, when serum creatinine and blood urea nitrogen have recovered. EPR imaging is an appropriate and useful method for the noninvasive evaluation of oxidative stress in the presence of renal injury.

Acute Kidney Injury↗
PubMed2004

Runx2 and Runx3 are essential for chondrocyte maturation, and Runx2 regulates limb growth through induction of Indian hedgehog.

The differentiation of mesenchymal cells into chondrocytes and chondrocyte proliferation and maturation are fundamental steps in skeletal development. Runx2 is essential for osteoblast differentiation and is involved in chondrocyte maturation. Although chondrocyte maturation is delayed in Runx2-deficient (Runx2(-/-)) mice, terminal differentiation of chondrocytes does occur, indicating that additional factors are involved in chondrocyte maturation. We investigated the involvement of Runx3 in chondrocyte differentiation by generating Runx2-and-Runx3-deficient (Runx2(-/-)3(-/-)) mice. We found that chondrocyte differentiation was inhibited depending on the dosages of Runx2 and Runx3, and Runx2(-/-)3(-/-) mice showed a complete absence of chondrocyte maturation. Further, the length of the limbs was reduced depending on the dosages of Runx2 and Runx3, due to reduced and disorganized chondrocyte proliferation and reduced cell size in the diaphyses. Runx2(-/-)3(-/-) mice did not express Ihh, which regulates chondrocyte proliferation and maturation. Adenoviral introduction of Runx2 in Runx2(-/-) chondrocyte cultures strongly induced Ihh expression. Moreover, Runx2 directly bound to the promoter region of the Ihh gene and strongly induced expression of the reporter gene driven by the Ihh promoter. These findings demonstrate that Runx2 and Runx3 are essential for chondrocyte maturation and that Runx2 regulates limb growth by organizing chondrocyte maturation and proliferation through the induction of Ihh expression.

Animals↗
PubMed2004

Surgical orthodontic correction of acromegaly with mandibular prognathism.

A male (30 years five months) who complained of mandibular prominence and masticatory dysfunction was diagnosed as a mandibular prognathic with acromegaly after cephalometric and endocrine examinations. The level of growth hormone (GH) subsequent to a transsphenoidal hypophysectomy had been controlled by medicines for about five years. Surgical orthodontic correction improved his occlusion and profile, but magnetic resonance imaging detected a recurrent adenoma in the cranial base during the retention period. The recurrence resulted in slight prognathic changes of the patient with a high level of GH. This is a case report of the treatment of an acromegalic patient discussing growth considerations that could influence the orthodontic treatment plan and long-term stability.

Acromegaly↗
PubMed2004

Validity of measurements for cycle-by-cycle variability of jaw movements: variability of chewing cycles in cases of prognathism.

Objective assessments of masticatory jaw movements for patients with a high degree of occlusal abnormalities are critical to elucidate the relationship between occlusal function and morphology. This study aimed to test the reliability and validity of measuring specific cycle-by-cycle variability of chewing jaw movements of patients with mandibular prognathism. The lower incisor-point movements were monitored using a 3D tracking device. Analyses consist of evaluations for the planarity of each cycle, cycle-by-cycle variances in orientations of the best-fit planes and instantaneous curvature of the trajectories. These spatio-temporal variabilities of chewing cycles for 12 adult females with good occlusion were compared with those for 12 female adult patients with mandibular prognathism. Five of the control subjects performed chewing on two separate occasions. Measurement outcomes were repeatable within each subject. For both groups, each single chewing cycle was characterized as reasonably planar. Orientations of the best-fit planes and curvatures of the trajectories during closing were more variable for patients than those for the control subjects. These findings suggest certain effectiveness of the present measurements of orientations of the best-fit planes and movement curvatures for scaling the variable nature of patients' masticatory jaw movements.

Adult↗
PubMed2004

Three-dimensional reconstruction of TMJ MR images: a technical note and case report.

MR images of the temporomandibular joint at occlusion and at various stages of mouth opening were registered and reconstructed three-dimensionally before and after a modified condylotomy in a patient with painful disk displacement. Following the condylotomy, the condyle/disk relationship had become normalized in all three planes of space at closed mouth and during mouth opening. The post-operative distances of the condylar and diskal paths had increased when compared with the preoperative distances. The three-dimensional visualizing method may, besides providing diagnostic advantages, be a valuable tool for qualitative and quantitative documentation of the efficiency of different treatment methods for normalization of the disk/condyle relationship in patients with TMJ disk displacement.

Adult↗
PubMed2004

Improvement in smoothness of the chewing cycle following treatment of anterior crossbite malocclusion: a case report.

This is a report of a case in which improvement in masticatory jaw movement kinematics occurred following orthodontic treatment. A patient who demonstrated a skeletal Class II jaw relationship, with anterior crossbite between the right upper and lower lateral incisors, underwent treatment with an edgewise appliance. The trajectories and smoothness of the patient's jaw-closing movement were compared before and after orthodontic treatment. The correction of the anterior crossbite allowed the patient to consistently close the jaw with wider lateral excursion. Furthermore, after treatment, smoothness of the jaw-closing movements increased significantly, and the velocity profile was characterized as closer to that predicted by the minimum jerk (maximum smoothness) kinematic model. These findings suggest the value of trajectory smoothness (jerk-cost) as an objective indicator of kinematic improvement in gum chewing. In addition, the correction of anterior crossbite is demonstrated to enable the patient to perform smoother jaw-closing movements during chewing.

Algorithms↗
PubMed2004

Evaluation of temporomandibular joint in patients with hemifacial microsomia.

OBJECTIVE: The purpose of this study was to elucidate positional relationships between temporomandibular joint (TMJ) components, including the articular discs, using magnetic resonance imaging (MRI) in patients with hemifacial microsomia (HFM). SUBJECTS AND METHODS: Twenty TMJs in 10 patients with HFM were examined at closed- and open-mouth positions using an MRI scanner. The condyle-fossa and disc-condyle relationships, disc configuration at the closed-mouth position, and the reduction of the disc at the open-mouth position were evaluated. RESULTS: On the unaffected side, the condyle-fossa and disc-condyle relationships appeared fairly normal at the closed mouth position. The disc-condyle relationship at the open-mouth position was also normal. The TMJ disc showed normal biconcave configurations at both closed- and open-mouth positions. On the affected side, there was considerable variation in the state of the TMJ. At the closed-mouth position, 5 of the 10 patients revealed fairly normal disc-condyle relationships, one patient showed anterior displacement of the disc, and four patients had no disc. Two patients appeared biconcave, three patients appeared biplanar, and one patient was hemiconvex. At the open-mouth position, the condyle and disc moved in harmony in five patients with normal disc-condyle relationships, but the disc was reduced in a patients with anterior disc displacement. The degree of the TMJ disc dysplasia did not necessarily correspond with the degree of mandibular dysplasia. CONCLUSIONS: The present study contributes to an improved understanding of TMJ pathology in patients with HFM. The results suggest that, in HFM patients, the examination of the TMJ using MRI is helpful for determining treatment procedures in mandibular distraction osteogenesis.

Adolescent↗
PubMed2004

Craniofacial morphology in an unusual case with nasal aplasia studied by roentgencephalometry and three-dimensional CT scanning.

OBJECTIVE: To examine the three-dimensional morphology of internal structures of the craniofacial region and present the orthodontic problems in an unusual case with nasal aplasia. PATIENT: The patient was an 11.5-year-old boy with aplasia of the nose and nasal cavity with extremely constricted nasopharyngeal airway. He did not have mental or somatic retardation. The patient had dacryostenosis. The morphology of the craniofacial structures was characterized by absence of septal structures, including cribriform plate, perpendicular plate of ethmoid bone, vomer, and septal cartilage; bony hypotelorism; midface hypoplasia; short and retrognathic maxilla with Class III jaw relationship; average mandibular plane angle; high arched palate; severe anterior open bite with bilateral posterior crossbites; and dental anomalies (agenesis of four maxillary permanent teeth, microdontia, taurodontism, and short roots). Thus, the patient had characteristic dentofacial phenotype, which might be caused by a combination of the primary anomaly and the functional disturbances secondary to the nasal obstruction.

Cephalometry↗
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↗