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Biomedical subjects

T Hanawa

Publications and source records attributed to T Hanawa.

At least 109 records · Page 6Linked to original sources
PubMed1988

Cytotoxicity of amalgams.

The purpose of this study was to compare the relative cytotoxicity of amalgams and to determine whether their toxicity depends upon composition and aging time, by means of a rapid and sensitive in vitro cell culture test. Zinc-containing amalgams showed higher cytotoxicity than did any other amalgams. High-copper amalgams had the same cytotoxicity as did the low-copper amalgam. The addition of selenium did not reduce the cytotoxicity of amalgam. Moreover, excessive additions of selenium increased the cytotoxicity of amalgam compared with that of a similar selenium-free material. The cytotoxicity of amalgam was decreased with aging time, possibly due to the combined effects of surface oxidation and further amalgamation.

Cells, Cultured↗
PubMed1987

Surface characterization of amalgams using X-ray photoelectron spectroscopy.

This study is the first to report on the use of x-ray photoelectron spectroscopy (XPS or ESCA) for studying the surface films (less than 10 nm thick) of aged amalgams. The concentrations and electron binding energies of the elements on the surfaces of four different amalgams aged for 20 min, one day, seven days, and 30 days were determined quantitatively. For comparison, the bulk compositions of the amalgams aged for seven days were also determined after removal of approximately 5 nm of material from the surface by argon-ion-sputtering. The XPS data revealed that the surface films of aged zinc-containing amalgams were not a simple oxide but were primarily composed of a (hydrated) tin and zinc oxy-hydroxide, whereas, in the zinc-free amalgams, the surface films were primarily a tin oxide. The concentration of mercury in this thin surface film after aging was depleted. This suggests that tin and/or zinc preferentially diffused to the surface and combined with oxygen, forming a surface film and diluting the mercury concentration in the surface. Another probable explanation for the depleted mercury is that a minimal amount of mercury in the surface film evaporated during the aging.

Copper↗
PubMed1987

[Prosthetic reconstruction of the trachea and carina].

We have performed prosthetic reconstruction of the trachea and carina in 12 patients since 1979. We used Neville's prosthesis in 7 patients and Katsura's prosthesis in 5 patients. Seven patients were operated on for lung cancer, 2 patients for adenoid cystic carcinoma of the trachea and the others for large cell carcinoma of the trachea, thyroid cancer and tuberculous granuloma, respectively. Prosthetic reconstruction of the trachea was performed in 4 patients. Carinal resection was performed in 8 patients: With right sleeve pneumonectomy in 4 patients, with right upper lobectomy in 2 patients and only carinal resection in 2 patients. Prosthetic reconstruction after the carinal resection was performed using 3 straight types, 1 curved type and 4 bifurcated types. With regard to the complications of the prosthetic reconstruction, dehiscence at the anastomotic site was seen in 5 patients, granulation in 4 patients, empyema in 3 patients, massive hemorrhage in 2 patients and migration of the prosthesis in 1 patient. Five patients survived more than 1 year. The longest survival time was 43 months. To prevent complications of the prosthetic reconstruction, we improved the anastomotic method, reinforced the anastomotic site with Marlex mesh and protected the surrounding vessels with Lyodura.

Adult↗