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Biomedical subjects

M Hada

Publications and source records attributed to M Hada.

At least 19 recordsLinked to original sources
PubMed1990

[Observation of oral actions using digital image processing system].

UNLABELLED: A new digital image processing system to observe oral actions is proposed. The system provides analyses of motion pictures along with other physiological signals. The major components are a video tape recorder, a digital image processor, a percept scope, a CCD camera, an A/D converter and a personal computer. Five reference points were marked on the lip and eyeglasses of 9 adult subjects. Lip movements were recorded and analyzed using the system when uttering five vowels and [ka, sa, ta, ha, ra, ma, pa, ba[. RESULTS: 1. Positions of the lip when uttering five vowels were clearly classified. 2. Active articulatory movements of the lip were not recognized when uttering consonants [k, s, t, h, r[. It seemed lip movements were dependent on tongue and mandibular movements. Downward and rearward movements of the upper lip, and upward and forward movements of the lower lip were observed when uttering consonants [m, p, b[.

Humans↗
PubMed1990

[On the viscoelastic properties of the palatal mucosa analyzed for the displacement of maxillary complete denture].

The condition of palatal mucosa caused by wearing a maxillary complete denture closely resembles a closed hydrostatic system. To clarify the viscoelastic properties of the palatal mucosa under such a condition, we measured as a function of the degree of denture displacement during biting movements. For this work, we developed three dimensional movement-measuring equipment. The following results were obtained: 1. The displacement of the maxillary complete denture during biting movements (loading and unloading of occlusal forces) could be approximated by an empirical formula of exponential function. This formula expressed the delayed elasticity characteristics of the viscoelasticity of the palatal mucosa. 2. Observation of the denture's displacement revealed that the movement of the palatal mucosa after occlusal forces are unloaded could be regarded as creep according to a Voigtian two-element model. 3. Denture displacement differed between occlusal force loading and unloading: dentures took longer to return to the original position during occlusal force unloading. 4. This time delay, indicating the degree of delayed elasticity of the palatal mucosa, was substantially shorter than the reported value based on local compression tests. Our study clearly shows that when a maxillary complete denture is worn, movement of the palatal mucosa approximates a closed system, and differs from localized open systems.

Biomechanical Phenomena↗
PubMed1990

[A study of the effectiveness of denture cleanser on human breath].

The purpose of this study is to measure the human breathes of denture wearers by using breath sensor, and to evaluate the influence of denture cleansing. The following results were obtained. 1. There is a possibility that the human breathes of full denture wearers may originate from their dentures. 2. There is a possibility that the cleansed dentures may cover the smell of the patient's oral mucosa itself and may reduce the apparent human breathes. Anyhow, the human breathes of denture wearers reduce significantly by using the denture cleanser.

Breath Tests↗
PubMed1990

[Stress distribution of supporting tissues under denture. Application of visco-elastic analysis in prosthetic field].

Viscoelastic finite element method was attempted to apply to the removable prosthodontic field. To examine the accuracy of this analysis, the results obtained from creep test of soft lining materials were compared with the calculated results by using this analysis. Stress relaxation in the supporting tissue under the upper complete denture was simulated by using viscoelastic analysis. The results were as follows; 1. The calculated results were in approximate agreement with experiment. 2. When the occlusal table of the denture was move 0.3 mm to the vertical direction, the calculated results indicated the soft tissue acted as a part of the stress relaxation in the supporting structures. 3. By using viscoelastic analysis, the time dependent deformation of the denture base and stress distributions in the supporting structures could be simulated.

Alveolar Process↗
PubMed1990

[A basic study on pressure distribution of supporting structures under complete denture. 1. Application of pressure dispersion analyzing system by using impedance grid sensor to measure the pressure of supporting structures under complete denture].

In order to measure the pressure distribution on supporting structures under complete denture, we used impedance grid pressure sensor and examined its accuracy and availability. The results were as follows: 1. The sensitivity of this sensor was high when the distance between electrodes was short. 2. This sensor showed large change in output voltage and high sensitivity in the case of soft elastic materials. 3. This sensor showed the high linearlity between output voltage and applied load. 4. This sensor showed hysteresis loop under cycle load. 5. Base line of this sensor that has the urethane rubber as elastic material was changed when the load was applied intermittently. We measured the pressure distribution over supporting bones under upper complete denture by using simulator of maxillary edentulous with this impedance grid pressure sensor. We could observe the pressure distribution and pressure region in detail and visually when the load was applied to the both occlusal tables evenly.

Alveolar Process↗
PubMed1989

[Development and application of an optical system to measure the movements of organs with soft tissue].

We proposed a new optical system to measure the movements of less accessible organs with soft tissue. The sensor unit is composed of a phototransistor and two LEDs. Two LEDs of light sources are driven by two phase signals with phase shift of 90 degrees. The distance between the sensor and the measuring object can be obtained as the function of the phase angle of reflex light signal detected by the phototransistor. The system can be easily constructed and provides simultaneous recordings of multiple points with the fast response in real time. The Relative precision is 0.5 mm and the resolution is 0.05 mm. Output characteristic of the system was less affected by the reflection factor of the object. We conducted to observe the tongue movements in speech production.

Humans↗
PubMed1989

[A case of primary gastric choriocarcinoma].

A 66-year-old man with a primary gastric choriocarcinoma is presented. The pre-operative diagnosis of the gastric barium examination and an endoscopy was an unusual gastric carcinoma in the antrum. At laparotomy, an abscess in the lesser sac that had developed by a tumoral penetrance was found. Thus a total gastrectomy and a lymphadenectomy with a reconstruction was performed. The resected specimen was found to be a Borrmann 1 type tumor, and a histological examination showed it to be a choriocarcinoma with a syncytiotrophoblast, that was immunostained by human chorionic gonadotropin (HCG). The physical findings however, disclosed no tumor in the testis. The serum HCG was found to be 1,380 IU/l on the 7th postoperative day, then a pulmonary metastases appeared and progressed, and the patient died on the 22nd postoperative day.

Aged↗
PubMed1987

[Fibronectin].

Explore the source record for details and available documents.

Fibronectins↗
PubMed1986

Covalent crosslinking of von Willebrand factor to fibrin.

Factor XIIIa crosslinks a limited number of substrates via epsilon(gamma-glutamyl)-lysyl bond formation. It crosslinks fibrin to itself, alpha 2-plasmin inhibitor and fibronectin to fibrin, and fibronectin to collagen. Results presented here show that plasma von Willebrand factor (vWF) is a substrate for factor XIIIa and can be crosslinked to fibrin during gel formation. vWF-fibrin crosslinking was studied in purified systems and in plasma with 125I-vWF and 131I-fibrinogen. vWF incorporation into fibrin increased with time or increasing factor XIIIa. After electrophoresis of dissolved clots, distribution of 125I and 131I was measured and showed that vWF was crosslinked to the alpha chain of fibrin and entered the high-mol-wt alpha polymer. vWF-fibrin crosslinking decreased the initial rate of alpha polymer formation. Crosslinking of vWF polymer to itself could not be demonstrated under physiologic conditions but occurred if vWF was reduced first. Factor XIIIa catalyzed incorporation of putrescine into both monomeric and polymeric vWF. Altogether, these studies indicate that factor XIIIa can readily form covalent bonds between glutamine in vWF and lysine in fibrin alpha chains. This reaction occurs readily in vitro when plasma clotting is slow and may occur in vivo under similar conditions.

Blood Coagulation Tests↗