Biomedical subjects

M Miyamoto

Publications and source records attributed to M Miyamoto.

724 records · Page 41Linked to original sources

PubMedDate not supplied

Diastolic mechanical properties of the left ventricle after global ischemia.

The purpose of this study was to evaluate left ventricular (LV) diastolic mechanical properties after induced global ischemia using reliable new methods. The diastolic function of nonoxygenated crystalloid solution (CC sO2) was compared with those of oxygenated crystalloid (CC cO2) and oxygenated fluorocarbon cardioplegic (FC cO2) solutions. Postischemic ventricular performance was studied in 3 equal (no. 7) groups of dogs subjected to 120 minutes of global ischemia induced at an average myocardial temperature of 18.5 +/- 1.4 degrees C. LV diastolic function (chamber and myocardial stiffness) and relaxation (the exponential fall in LV pressure) were evaluated by sonomicrometry and Millar micrometers before ischemia and at 45 and 60 minutes after ischemia. LV chamber and myocardial stiffness in the CC sO2 group was significantly (p less than 0.05) elevated after ischemia, while the CC cO2 and FC cO2 groups did not show increases in LV chamber and myocardial stiffness after ischemia. LV relaxation before and after ischemia was not changed in any group. The myocardial water content of the CC sO2 group was significantly higher than that of the CC cO2 and FC cO2 groups (p less than 0.05). We conclude that (1) the postischemic increase in LV chamber stiffness in the CC sO2 group was dependent not only on the increase in intrinsic myocardial stiffness but also due to an increase in myocardial edema, and (2) there was no correlation between the LV relaxation rate and the leftward shift of diastolic compliance curves in the CC sO2 group.

Animals↗

PubMedDate not supplied

Reinforcement of acrylic resin denture base with a Ni-Cr alloy plate.

A pilot study was conducted to evaluate the strengthening effect of a Ni-Cr metal plate on an acrylic resin test specimen. Test specimens were retained using a mechanical method and adhesion with 4-META resin. Three positions of the metal plate were evaluated: on the compression surface, on the tension surface, and in the middle layer. A three-point bend test was used to compare physical properties of the specimens with metal-plate reinforcement to a resin specimen without reinforcement. No advantage was derived from placing the metal plate in the center of the resin. Both methods of retention produced improved physical properties when placed on either the compressive or tensile side, but the greatest advantages were gained when an adhesive-retained plate was placed on the side in tension.

Acrylic Resins↗

PubMedDate not supplied

A "supralethal dose phenomenon" revealed by cancer of the maxillary sinus.

In this paper a so-called "supralethal dose phenomenon" is reported. Two groups of patients, all of whom were carrying proved squamous cell carcinoma of the same clinical stage in their maxillary sinuses, were compared after radiotherapy in our department. The radiotherapies applied to the two groups were very similar in terms of fraction number, treatment period, dose distribution and immobilization technique, but differed in dose, i.e., 5,500 cGy for one group of 9 patients and 5,750 cGy for the other group of 20 patients. The five-year survival rates of the two groups were 8/9 and 10/20, respectively, and the difference was statistically significant (p less than 0.05). All patients were observed for at least five years. Except for tumor stage, the status of the patients in the two groups, including primary site of the tumor in the sinus, patients' age and cause of death for the failed cases, are also discussed in detail.

Adult↗

PubMedDate not supplied

Radiographic analysis of a two-piece apatite implant: Part II. Preliminary report of 2-year observation.

Marginal bone height and bone density were evaluated for 2 years after two-piece dense hydroxyapatite implant (Apaceram) placement using standardized radiography and digital image processing. The chronological changes in marginal bone height were divided into three groups: Group I-level was constant or became higher with time; Group II-bone decreased gradually after superstructure placement; and Group III-bone decreased in height rapidly after abutment placement. Bone density around the successful Apaceram implant, especially in the crestal region, increased clearly. The results suggest that bone resorption/formation around the implant is related to occlusal stress, and that adequate occlusal stress should be exerted on the implant at each phase after the implant placement.

Adult↗