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Biomedical subjects

M Sakuda

Publications and source records attributed to M Sakuda.

At least 91 records · Page 5Linked to original sources
PubMed1993

Changes in Hox1.6, c-jun, and Oct-3 gene expressions are associated with teratocarcinoma F9 cell differentiation in three different ways of induction.

To obtain information on the mechanism of teratocarcinoma cell differentiation, the expression of genes having a specific role in gene regulation was examined using three different methods of inducing differentiation: drug treatments with retinoic acid (RA) and sodium butyrate, and a genetic approach using ts mutants. The RAR-beta and MK genes were induced specifically by RA treatment, which indicates that these two genes are solely RA responsive. By contrast, a change in c-jun, Hox1.6, and Oct-3 gene expression was observed in all three methods of F9 cell differentiation. These findings suggest that these three genes, whether down-or up-regulated, play an important and key role during teratocarcinoma cell differentiation.

Animals↗
PubMed1993

[A FEM study for the biomechanical comparison of labial and palatal force application on the upper incisors. Finite element method].

The present study was designed to compare the biomechanical response of upper incisors to labial and lingual force applications. A three-dimensional finite element model was developed to analyze tooth displacement and stress distribution in the periodontal ligament. Lingually and apically directed forces of 1 N were applied at one point on the labial and at three points on the lingual surface of the crown. Tooth displacement and stress distribution resulting from lingual force applications were compared with those from the labial side. The following results were obtained: 1. Lingual horizontal forces produced similar patterns of tooth displacement and stress distribution, irrespective of the point of application (labial--lingual). 2. Apically directed vertical forces applied at the lingual points produced more uniform tooth displacements and stress distributions, although the force applied on the lingual side close to the CEJ, which happened to be most distant from the tooth's long axis, generated a pattern of movement somewhat different from the remaining two lingual force applications. The present results suggest the crucial role of the positional relation between the long axis of the tooth, respectively the center of resistance, and the point of force application. It can be deduced that lingual force application may produce more optimal tooth movement in terms of intrusion and subsequent stress distributions in the periodontal ligament.

Biomechanical Phenomena↗
PubMed1993

Pedunculated cavernous hemangioma. A case report.

A rare case of pedunculated hemangioma of the oral mucosa has been reported. Clinically, it was diagnosed as a fibroma induced by irritation, but histologic examination followed to excisional biopsy demonstrated that it was a cavernous hemangioma.

Aged↗
PubMed1993

Defects of the rat premaxilla as a model of alveolar clefts for testing bone-inductive agents.

Critical-sized defects were made in the premaxillary bone of Wistar male rats using a surgical trephine and a low-speed dental engine as a model of the maxillary alveolar cleft for testing bone-inductive agents. The defects were treated with either 7 mg of demineralized bone matrix (DBM) or were left nongrafted. The nongrafted group healed mainly with fibrous connective tissue, with a small amount of bone formation at the periphery. There was no significant change in alkaline phosphatase activity and 45Ca incorporation. The DBM-grafted group produced new bone with osseous bridging in the defect by day 35. Alkaline phosphatase activity increased significantly from day 10, reaching a maximum on day 14, and 45Ca incorporation increased on day 14. These results indicate that this nonhealing bony wound of the premaxilla in rats may be useful as a model for studying the effect of bone-inductive agents on the healing of alveolar clefts.

Alkaline Phosphatase↗
PubMed1993

Stress distributions in the maxillary complex from orthopedic headgear forces.

The present study was conducted to investigate stress distributions in the maxillary complex from headgear forces by means of three-dimensional finite element analysis. A posteriorly-directed force of 1.0 Kgf was applied to the maxillary first molars in the directions parallel and 30 degrees inferior to the occlusal plane. In the lower regions resisting posterior displacement of the complex, large normal and shear stresses were observed. Meanwhile, the regions resisting upward displacement experienced larger than normal stresses. A downward force produced slightly larger stresses than a parallel force and varied the nature of stresses from compressive to tensile or vice versa in the temporozygomatic suture. Thus, the stress distributions in the sutures varied according to their anatomic locations relative to force directions. The maxillary complex exhibits postero-inferior displacement with clockwise rotation from the horizontal headgear force. This becomes more prominent as the direction of force becomes more inferior.

Adolescent↗
PubMed1993

Craniofacial morphology of adolescent mandibular prognathism.

Morphological features of the craniofacial complex during orthopedic chin cup therapy were investigated in growing patients with mandibular prognathism. Lateral cephalograms of 30 subjects (15 boys and 15 girls, mean age: 9.04 +/- 1.29 years), taken at four different stages during treatment, were analyzed for 14 measurements. These measured values were standardized by use of Japanese controls and then evaluated to investigate longitudinal changes in the craniofacial morphology at the four different stages. Further, factor analysis was used to compare factors describing the craniofacial morphology for the initial and final stages. Dimensional changes of the mandible were not easily produced even if orthopedic treatment was conducted, whereas the maxilla exhibited a tendency to approach the normal range of the controls. Positional changes of the complex, the backward and downward repositioning of the mandible in particular, played an important role in altering a profile from prognathic before treatment to orthognathic at the end of treatment. Craniofacial morphology was similar pretreatment and posttreatment, although the orthognathic factor became more prominent when associated with positional changes of the mandible at the end of treatment.

Adolescent↗
PubMed1993

Changes in dentofacial morphology in skeletal Class III children treated by a modified maxillary protraction headgear and a chin cup: a longitudinal cephalometric appraisal.

The purpose of the current report was to investigate cephalometrically possible orthopaedic effects of a modified maxillary protraction headgear (MPH) on dentofacial morphology in skeletal Class III female patients before and during the pubertal growth spurt period. Sixty-one patients were divided into three groups, the prepubertal (7-10 years, n = 20), the mid-pubertal (10-12 years, n = 22), and the late pubertal (12-15 years, n = 19) groups. Longitudinal record sets of subjects with acceptable good occlusion were used as the control. Patients were treated by protracting from the upper canine area. The mean ages at completion of the MPH treatment were 8.9, 11.3, and 13.3 years for the three test groups, respectively. The average treatment time was 1.1, 1.0, and 1.4 years for each of these groups. Lateral cephalograms at the start and completion of use of the MPH were collected. Annual differences were calculated from these paired records for each of 21 dentoskeletal variables in the test groups and compared to those of the control group. The pre- and mid-pubertal groups revealed significant increases in both the SNA (P < 0.01 and P < 0.001) and the maxillary length (Ptm-A/PP, P < 0.01), while the late pubertal group showed a less significant increase in the SNA (P < 0.05) alone. The decreased SNB, increased ANB and SNMP of the pre- and mid-pubertal groups was accounted for by the backward and downward rotation of the mandible. The results suggest possible orthopaedic effects of the MPH on dentofacial morphology in young females when it is applied before or during acceleration of the pubertal growth spurt.

Adolescent↗
PubMed1993

Biomechanical changes of the mandible from orthopaedic chin cup force studied in a three-dimensional finite element model.

Biomechanical changes of the mandible from orthopaedic chin cup forces were investigated by means of finite element analysis. A three-dimensional model of the mandible including the temporomandibular joint was developed for stress analysis in the mandible. A chin cup force of 400 gf was applied at pogonion on the mandible in the direction toward the condyle. From the stress analyses, it was revealed that (1) uniform tensile stresses were produced at the outer borders of the mandible, (2) compressive stresses were induced in the centre of the mandible, (3) compressive stresses were generated widely on the surface of the condyle, and (4) stresses on the condyle were smaller in magnitude than those in the mandibular corpus. These results coincide with morphological changes of the mandible revealed in previous studies and, thus, indicate an association of stresses with remodelling of the mandible from chin cup therapy applied to adolescent patients with mandibular prognathism.

Adolescent↗
PubMed1993

Effect of centrifugal force on growth of mouse osteoblastic MC3T3-E1 cells in vitro.

The effect of biomechanical force on growth of skeletal tissue was studied in monolayer cultures of mouse osteoblastic MC3T3-E1 cells which were centrifuged at 320 g for 15 min to 72 h in a CO2 incubator. Centrifugation of the cells for 30 min in low concentrations (0.3 or 1%) of fetal bovine serum (FBS) caused a two-fold increase of [3H]thymidine incorporation at 20 h from the start of centrifugation. However, centrifugation under 10% FBS caused no increase in [3H]thymidine incorporation into DNA. Under 0.3% FBS, [3H]thymidine incorporation increased in a manner dependent on the period of centrifugation and reached a maximum when the cells were centrifuged for 3 h. Stimulation of DNA synthesis by centrifugation was abolished in the presence of H-7, an inhibitor of protein kinase C. Moreover, conditioned medium collected from the centrifuged cultures increased [3H]thymidine incorporation by two-fold over the basal when added to a quiescent culture of MC3T3-E1 cells. These results suggest that centrifugal force stimulates growth of osteoblastic cells through autocrine secretion of some diffusible growth-promoting activity. On the other hand, centrifugation of the cells inhibited induction by FBS of alkaline phosphatase activity and calcium-uptake, two indices of the differentiated phenotype of osteoblasts.

3T3 Cells↗
PubMed1993

Association between malocclusion and temporomandibular disorders in orthodontic patients before treatment.

The association between malocclusion and the prevalence of temporomandibular disorders (TMD) was studied in an orthodontic patient population before orthodontic treatment was started. A total of 305 patients, 232 with general malocclusion and 73 who also had cleft lip or palate, were given a questionnaire about the subjective symptoms of TMD. Clinical examinations for type of malocclusion and TMD signs were also conducted. No significant differences in the prevalence of TMD were observed between the sexes or between the two patient groups. Temporomandibular joint sounds and difficulty of jaw movement were the most common of the TMD signs and symptoms. Open bite, posterior crossbite, and deep bite were the most prevalent types of malocclusion in both groups. Thus, some specific types of malocclusion were significantly associated with the occurrence of TMD.

Adolescent↗
PubMed1993

Conditioned medium factors of rabbit cranio-facial chondrocytes stimulate their own syntheses of sulfated glycosaminoglycans and DNA.

Previously, we reported methods for isolating chondrocytes from the craniofacial cartilage and culturing them in vitro. The cells actively synthesize glycosaminoglycan (GAG), a marker of the differentiated phenotype of chondrocytes and respond well to PTH and glucocorticoids. It has been suggested that chondrocytes produce somatomedin-like growth factors which support their own growth and GAG synthesis. In the present study, we reported studies on the effect of conditioned medium obtained from cultures of rabbit craniofacial chondrocytes on GAG and DNA syntheses in the same chondrocyte cultures. Serum-free medium, conditioned by exposure to rabbit chondrocytes from mandibular condyle, nasal septum and sphenooccipital synchondrosis in monolayer culture stimulated not only the synthesis of GAG by the same cells but also their own DNA synthesis. The stimulation of the syntheses of GAG and DNA by the conditioned-medium factor were concentration-dependent. In addition, these three kinds of conditioned media stimulated GAG and DNA syntheses of other types of chondrocytes. These findings suggest that rabbit chondrocytes from the craniofacial complex release factors into the culture medium that enhance their own growth and expression of the differentiated phenotype of chondrocytes as well as that of costal chondrocytes.

Animals↗
PubMed1993

Solitary eosinophilic granuloma of bone occurring in the buccal mucosa: report of a case.

Eosinophilic granuloma of bone is not uncommon in the craniofacial region (Anderson and kissane, 1977), and it sometimes occurs in organs such as the lung, stomach and spleen. However there are only few reports on solitary eosinophilic granuloma of bone occurring in oral soft tissue. In this report, we describe a case of eosinophilic granuloma of bone occurring in the soft tissue of a 40-year-old woman.

Adult↗
PubMed1993

Orthognathic surgical approach and partial glossectomy to a skeletal 3 adult open bite.

Combined orthodontic treatment with orthognathic surgery and partial glossectomy were simultaneously performed in an adult male patient with mandibular prognathism and open bite from the lower right to the left first molars. Total active treatment period was 15 months. During the retention period, a tooth positioner was given to obtain proper interdigitation from set-up models. The post-surgical occlusion has been stable without any complication of the mandible and the tongue.

Adult↗
PubMed1993

Changes in bone formation during experimental tooth movement after denervation of the rabbit inferior alveolar nerve.

The effects of nerve fibers on bone formation during tooth movement were examined using eight rabbits with denervation of inferior alveolar nerve (IAN). IAN on one side for all the animals was denervated and and sham operation was performed on the other side of denervation. The distance of tooth movement on the denervated and sham operated sides was very similar and 1.20 +/- 0.17 and 1.24 +/- 0.12 (mean +/- S.D. mm), respectively. From the fluorescent observations, the denervated and sham operated sides in the animals without tooth movement i.e. control group showed similar morphology. The animals with tooth movement i.e. experimental group showed significant new bone formation than the control group. However, the amount of new bone formation on the denervated side was less than the sham operated side. It was suggested that the nerve fibers might play some roles on bone formation during the tooth movement.

Alveolar Process↗
PubMed1993

Diagnostic arthroscopy of temporomandibular joint on outpatient. Review of 47 examinations, 40 cases.

The diagnostic arthroscopy was performed on 47 temporomandibular joints from 40 patients having anterior disc displacement without reduction with restricted mouth opening or painful anterior disc displacement with reduction. All patients were outpatients and subjected to arthroscopic examination under local anesthesia. Previous to arthroscopy, routine clinical and radiographic examination, and magnetic resonance imaging were carried out for all joints. Adhesion was better observed by arthroscopic examination, perforation was suggested by magnetic resonance imaging as well as arthroscopic examination, and bone change was better observed by magnetic resonance imaging. However diagnostic arthroscopy should be considered as an invasive examination, it is practical to the clinician and patient as complementary to decide the indication of arthroscopic surgery, open surgery (diskectomy) or maintenance of conservative treatment.

Adult↗
PubMed1992

An analytic method for evaluating condylar position in the TMJ and its application to orthodontic patients with painful clicking.

The purpose of this study was to develop a new method for evaluating the three-dimensional position of the mandibular condyle relative to the glenoid fossa and further to investigate its clinical application to orthodontic patients with temporomandibular disorders (TMD). A three-dimensional configuration of the temporomandibular joint was constructed by 108 triangles for the condyle and 180 triangles for the glenoid fossa. The shortest distance between the condyle and glenoid fossa (CGFD) was calculated in the model along a line perpendicular to the center of gravity of a triangle on the condyle. The CGFD was determined in the anterior, posterior, middle, lateral, and medial areas on the condyle. Preliminary investigation revealed that the present technique is accurate, regardless of condylar rotation and/or inclination to the tomographic table. The technique was applied to the diagnosis of orthodontic patients with painful clicking and TMD. It is shown that the present approach provides a method for evaluating the positional relationship between the mandibular condyle and glenoid fossa in patients with TMD.

Adolescent↗
PubMed1992

Integrated information-processing system in clinical orthodontics: an approach with use of a computer network system.

A computer network system has been developed in the Orthodontic Clinic, Osaka University Dental Hospital, to improve treatment efficiency and patient service. The system consists of a 32-bit host computer, its peripheral units, and personal computers connected to the host computer by data-transmission circuits, making up a local area network (LAN). It is possible in this system to integrate various types of data, such as the patient's basic information, treatment records, image data, and diagnostic analysis results to construct a relational database. It has been shown that the computer system developed in the orthodontic clinic has various clinical advantages.

Databases, Factual↗