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Biomedical subjects

M Sakuda

Publications and source records attributed to M Sakuda.

At least 127 records · Page 7Linked to original sources
PubMed1991

Production of self-migration stimulating factor by metastatic human malignant melanoma cells established in culture.

Establishment of human malignant melanoma of hard palate cell line derived from metastatic foci in lymph node is reported. We name it HM162. The shape of HM162 was almost spindle. HM162 cells secreted a factor into culture medium which stimulates motility of HM162 cell itself, and the mode of stimulated migration of HM162 cells were activated random migration, that is chemokinesis.

Cell Movement↗
PubMed1990

The distribution of vasoactive intestinal polypeptides and calcitonin gene-related peptide in the periodontal ligament of mouse molar teeth.

The distribution of VIP- and CGRP-containing nerve fibres was examined by indirect immunofluorescence. There were many such fibres in the lower third of the ligament, some around the blood vessel close to the socket wall. In the middle third of the ligament, some CGRP-containing fibers entered from the lateral wall of the socket; this type of fibre was more numerous in the lower third than in middle third. There were some VIP-containing fibres but no CGRP-containing fibres in the ligament surrounding the furcation of the molar roots.

Alveolar Process↗
PubMed1990

Insolubilized properties of UV-irradiated CO3 apatite-collagen composites.

To examine the response to biological hard tissues, a carbonate-containing hydroxyapatite with chemical composition and crystallinity similar to those of bone was synthesized at pH 7.4 and 60 degrees C. The apatite powder was mixed with collagen solution, whose antigenicity had been removed by enzymatic treatment, and formed into apatite-collagen pellets. After insolubilization by UV-irradiation for 4 h, the composites showed remarkably reduced disintegration and maintained their shape under 3.6 MPa of stress after 1 wk incubation in 0.9% NaCl solution. They showed good biocompatibility when implanted beneath the periosteum cranii of rats. The UV-irradiated sample kept its features well and was packed with newly created material 3 wk after implantation.

Animals↗
PubMed1990

Alveolar soft-part sarcoma of the tongue. Report of a case.

A case of alveolar soft-part sarcoma (ASPS) of the tongue in a 19-year-old boy is presented. He underwent a hemiglossectomy and received chemotherapy and has been free of disease for 3 years. The origin of intracytoplasmic periodic acid-Shiff(PAS)-positive crystals found in the tumor and the histogenesis of ASPS are briefly discussed.

Adult↗
PubMed1990

Stimulation of proteoglycan and DNA syntheses in chondrocytes by centrifugation.

So that the effects of biomechanical forces on the proliferation of chondrocytes and their proteoglycan synthesis could be studied, growth-plate and articular chondrocytes were maintained separately as packed masses in centrifuge tubes in the presence of 10% serum. In these conditions, the cells became re-organized into cartilaginous tissue in seven days. After ten days, they were centrifuged at gravities (g) of 1.3-27 for 24 h in a CO2 incubator. Control cells were maintained in the CO2 incubator without centrifugation. Centrifugation of growth-plate chondrocytes at 3 g resulted in a two-fold increase in incorporation of [35S]sulfate into proteoglycans, but had little effect on their [3H]thymidine incorporation into DNA. On the other hand, centrifugation of articular chondrocytes at 3 g for 24 h caused 1.5-fold increases in both [35S]sulfate incorporation into proteoglycans and [3H]thymidine incorporation into DNA. These results suggest that biomechanical forces have different effects on the growth and differentiation of articular and growth-plate chondrocytes.

Animals↗
PubMed1990

New type metal bracket for suppression of resin remaining in debonding.

A new type of metal bracket was prepared to minimize the destruction at the bracket-resin interface and to suppress resin from remaining on the tooth surface in debonding. The brackets were made of stainless steel and had a modified cylindrical outward shape (phi 3.8 mm x 1.8 mm), twin-type wings, and a 0.018 inch (0.457 mm) slot. Retentive forces and debonding aspects of residual resin for the brackets were studied using three representative adhesives. The mean tensile strengths at the bracket-resin interface were over 80 kgf/cm2 for all three resins. As the quantitative evaluation for the residual resin condition, a resin remaining ratio (RRR) was adopted. The aspects of the residual resin differed according to the type of adhesive resin used. Almost no resin was detected on the tooth surface just below the central part of the bracket, and even for the peripheral part which did not have an effective resin retention form, the RRR was under 30% for the heavily filled resin.

Acrylic Resins↗
PubMed1990

A new type ceramic bracket for suppression of resin remaining in debonding.

A new type of ceramic bracket was prepared to minimize the destruction at the bracket-resin interface and to suppress resin remaining on the tooth surface in debonding. The brackets were of a chemical bonding type, and had a box-formed cavity in the bracket base to hold resin, a 0.018 inch slot, and twin-type wings. Impact strengths and debonding aspects of the residual resin were studied. The impact strengths of the brackets seemed to exceed the desired level, compared to other control ceramic brackets or metal brackets. A resin remaining ratio (RRR) was adopted as the quantitative evaluation for the residual resin condition. Mean RRR's of the brackets were about 10%, which was a very low value in comparison to the other brackets.

Ceramics↗
PubMed1990

Prevalences of malocclusions and dental caries in molars in female adolescents.

Prevalences of malocclusions and dental caries in molars were investigated on a database of high school students collected between 1977 and 1986. A total of 6,665 schoolgirls were evaluated. The proportions of 54.1% in the seventh grade and 56.6% in the tenth grade students were judged as having malocclusions. The prevalences of dental caries for the lower first and the second molars were significantly higher (p less than 0.001) than those for the upper opponents during the observation period. The prevalence of dental caries increased linearly for all kinds of molars in accordance with age, but they were lower than those reported by the Ministry of Health and Welfare in Japan determined for the entire nation. The percent of dental caries for the second molars revealed abrupt increases from 10% at the seventh grade to 50% at the 12th grade. These changes were particularly noticeable between the eighth and the tenth grades. These results suggest the significance of oral health care education during the adolescent period based on a long-term cooperation made by dentists, school nurses, teachers through the participation of students into the oral health care programme.

Adolescent↗
PubMed1990

Meniscectomy operation as a surgical treatment for internal derangement of the temporomandibular joint in our department.

This paper describes the surgical treatment of six patients with internal derangement of the temporomandibular joint (nine joints). Meniscectomy was performed on all the patients, because severely advanced cases in which the articular disk could not be preserved or replaced were chosen. Our surgical technique and the results of short-term follow up are presented. Indications of meniscectomy and the criteria for postoperative evaluation are also described. The postoperative outcomes were assessed as "good" for seven joints in five patients and as "acceptable" for two joints in one patient.

Aged↗
PubMed1990

Association between mechanical stress and bone remodeling.

Stress patterns and levels were analyzed by use of the three-dimensional finite element method. Three-dimensional models were constructed for the human upper central incisor (1205 nodes and 920 elements) and the sheep metacarpus (240 nodes and 128 elements). Orthodontic and orthopedic forces were applied to the tooth and the bone, simulating orthodontic tooth movement and experimental loading test for the bone. Three principal stresses were determined in the alveolar bone and the sheep long bone. The following results were obtained. 1. Stress distributions in the lateral alveolar bone were similar to those with bone deformation from cantilever bending mode. On the medial surface of the alveolar bone, a bending stress was observed, however, remaining stresses exhibited changes corresponding to those in the PDL produced by tipping displacement of the tooth. 2. In the sheep long bone, tensile and compressive stresses were induced on the dorsal and volar sides, respectively. The magnitude of stresses was greatest at the mid-diaphyseal region. Compressive and tensile stresses were related with bone resorption and apposition. The magnitude of principal stresses was almost proportional to dimensional changes of the bone at the mid-diaphyseal region. Bone remodeling in the long bone is related with mechanical stress, principal stress in particular, indicating that remodeling of the alveolar bone may be induced by application of orthodontic force in addition to conventional change of the bone adjacent to the PDL. Thus, it is shown that mechanical stress in living structures may be a trigger to induce biological remodeling of bones.

Alveolar Process↗
PubMed1990

[An evaluation of 3-dimensional position of mandibular condyle to glenoid fossa using tomogram: an analytical technique and its clinical application].

In recent years, temporomandibular disorder (TMD) is occasionally found among orthodontic patients and has become a great concern in orthodontics. From this point of view, a certain technique has been hopefully anticipated for diagnosis and treatment planning. The purpose of this study was to develop a new method for evaluating three-dimensional position of the mandibular condyle relative to the glenoid fossa and also to investigate its clinical application. Seven-layered tomograms were taken and contours of the condyle and glenoid fossa were traced on an acetate paper. These contours were entered into a personal computer by use of a digitizer and were equally divided into 9 parts for the condyle and 15 parts for the glenoid fossa, consisting of 10 and 16 points on the contours of condyle and glenoid fossa. Three-dimensional configuration of the TMJ was thus constructed by 108 triangles for the condyle and 180 triangles for the glenoid fossa. The shortest distance between the condyle and the glenoid fossa (CGFD) was then calculated along a perpendicular line to center of gravity of a triangle on the condyle. For evaluating the position of the condyle to the glenoid fossa easily in a three dimensional space, surface of the condyle was divided into five areas, i.e. anterior, posterior, middle, lateral and medial areas. In order to investigate whether or not the CGFD is accurate enough to identify the distance between surface of the condyle and glenoid fossa, a model of hemi-spherical solid shell was made, of which the thickness is 3.0 mm. Tomograms of the model were taken to analyze the thickness. Direct measurement of the same area was also made by calipers. Two means were approximately 3.0 mm, which is the thickness itself and no significant differences were indicated at 5% level of confidence. The present technique was applied to diagnosis of an orthodontic patient with painful clicking as TMD. The analyzed CGFDs were coincident with clinical symptom. It is shown that the present approach provides an availability and a possibility to evaluate positional relationship between the mandibular condyle and the glenoid fossa of patients with TMDs.

Humans↗
PubMed1990

[A cephalometric, electromyographic and kinesiographic appraisal of a patient with mandibular prognathism and anterior openbite malocclusion before and after surgical orthodontic therapy: a case report].

A 19-year-old female patient with skeletal 3 and anterior openbite malocclusions was treated by a surgical orthodontic approach. A glossectomy was also performed. Cephalometric, electromyographic and kinesiographic records were taken before and after the treatment. The treatment results were as follows: 1. Esthetic improvement in facial profile and static alignment and intercuspation of teeth was obtained. 2. The dimension of the tongue with respect to that of the oral cavity proper measured on the lateral cephalograms revealed a value similar to that determined for the control data after the active treatment. 3. The proportion of reversed strokes with respect to the total chewing strokes increased at the completion of the active treatment both for the right- and the left-sided chewings, but it decreased during the retentive period. 4. At the initial stage, an earlier onset of the masseter muscle activity relative to the temporal muscle group was determined, while the temporalis muscles showed an earlier onset of activity in the postoperative phase. 5. The durations of chewing strokes became shortened in a postoperative phase both on the working and the balancing sides. This observation was particularly significant for the opening and the closing phases. In addition, the proportion of the duration of significant temporalis muscle activity with respect to that of the concomitant chewing stroke increased. 6. Anterior temporalis muscle and masseter muscle activity during clenching performance revealed a value similar to the control data. In summary, the current case suggests that the patients who receive surgical orthodontic treatment require sufficient time to obtain functional readaptation during the retentive period.

Adaptation, Physiological↗
PubMed1990

[Prevalence of malocclusions and demand for orthodontic treatment among students at a women's high school].

Prevalences of malocclusions were investigated in a sample of 3,520 girls recorded between 1984 and 1986 at a private high school. Also, proportions of students who had received and were under treatment were surveyed for 3,501 students in 1989. In addition, ratios of a number of those who were judged to reveal maxillary protrusion with respect to that of the whole sample examined were evaluated as a function of overjet. The results of the surveys are as follows. SURVEY I) A total prevalence of malocclusion was 57.9% in the Grade 7 (G7) and 56.4% in the Grade 10 (G10). Among malocclusions surveyed, maxillary protrusion was found in 8.1% of the G7 and in 7.8% of the G10. Deep overbite was determined in 7.9% of the G7 and in 7.6% of the G10, mandibular protrusion was found in 2.4% of the G7 and in 2.7% of the G10. Edge-to-edge incisor relationships were determined in 6.4% of the G7 and in 7.6% of the G10. Anterior open bite was found in 2.4% of the G7 and in 2.9% of the G10. Crowding was found in 37.3% of the G7 and in 33.9% of the G10. SURVEY II) Prevalence of students who had orthodontic treatment at the time of survey, was 6.4% in the G7, 7.0% in the G8, 6.0% in the G9, 6.0% in the G10, 5.4% in the G11, and 3.6% in the G12. Those who had had orthodontic treatment revealed proportions of 8.1% in the G7, 8.0% in the G8, 7.7% in the G9, 11.3% in the G10, 12.2% in the G11, and 13.7% in the G12 students. SURVEY III) A proportion of 73.5% of those who had overjets more than 6 mm were judged to have maxillary protrusion.

Adolescent↗
PubMed1990

[Changes in efficiency of orthodontic tooth movement resulting from differences in bracket materials].

The distance of distal movement of the lower canine was measured, using metal tooth with metal bracket and three types of ceramic bracket (polycrystal alumina x 2, zirconia x 1). Sizes of the wires used in this experiment were 0.018" round, 0.016" x 0.022" and 0.17" x 0.022". The bracket slot and the wire surface employed in the experiment were observed by use of stereoscopic microscope and S.E.M. The following results were obtained. 1. The distance of tooth movement with three types of ceramic bracket was significantly less than that with the metal bracket. 2. Rate of decrease in tooth movement with three types of ceramic bracket ranged from 30% to 60% in comparison with the metal bracket. 3. The wire surface was obviously scratched by the ceramic brackets, whereas slight scratch was observed on the wire with the metal bracket. 4. The distance of tooth movement decreased associated with an increase of wire size. 5. The distance retracted from the cuspal position was less than that from the cervical point. It was shown that efficiency of tooth movement was significantly reduced by the use of ceramic brackets in comparison with the metal bracket. This result seems to be caused by the frictional resistance between the wire and ceramic bracket. It is suggested that refinement of ceramic brackets, slot edge and surface in particular, would produce more efficient and desirable tooth movements in clinical orthodontics.

Ceramics↗
PubMed1990

[Multiple malignant tumors combined with oral cancer from annual of the pathological autopsy cases in Japan, 1984-1988].

During the 5-year period from 1984 to 1988, a total of 944 cases had been presented multiple (3 or more) primary malignant tumors in annual of the pathological autopsy cases in Japan. Forty-one cases (4.3%) had lip and oral cancer. Of this group, triple were described 36 cases, quadruple 3 cases and more discrete multiple 2 cases, respectively. It is more frequent in men than in women, the ratio being 12.7:1. The age range is from 34 to 86 years with a mean of 66.9 years. In these cases with oral cancer, the another primary site is almost always found in digestive system (90.2%), e.g. esophagus (36.6%), stomach (34.1%) and colon and rectum (34.1%).

Adult↗
PubMed1990

[Treatment of obstructive sleep apnea with a mandibular repositioning appliance].

A patient with obstructive sleep apnea has been treated by means of a mandibular repositioning appliance made of silicone rubber. The patient is a male and 54 years old with a slim body and complained a excessive daytime sleepiness and unsatisfied sleep. A lateral head plate revealed retruded mandible and narrow A-P diameter in the lower part of oropharynx. Moderate frequency of apnea was found in the initial all-night polysomnographic recording. The mandible has been brought forward by 5 mm and downward by 11 mm, which enlarges the diameter of oropharynx anterio-posteriorly by 2-3 mm. Since the appliance has been inserted during bed-time, the daytime sleepiness and unsatisfied sleep has been eliminated. The second polysomnographic recording revealed significant increment of deep NREM sleep and REM sleep and decrement of arousal during sleep after insertion of the appliance. It is indicated, therefore, that the application of the mandibular repositioning appliance is one of the effective methods for the treatment of obstructive sleep apnea.

Humans↗