Biomedical subjects

M Miyazaki

Publications and source records attributed to M Miyazaki.

1,282 records · Page 72Linked to original sources

PubMedDate not supplied

Limited-sampling models for estimation of the carboplatin area under the curve.

BACKGROUND: The area under the curve (AUC) of free carboplatin, is a major determinant of toxicity and response. A conventional pharmacokinetic study to determine AUC requires frequent blood sampling. One strategy for overcoming this problem is to apply a limited sampling model (LSM). MATERIALS AND METHODS: We developed LSMs by stepwise forward multiple regression analysis using 27 data series from 24 patients with lung cancer (training data set) who received carboplatin in combination with oral etoposide. The models were then validated using 24 data series from 18 patients (test data set). RESULTS: In the test data set, the single-sample model was confirmed to give excellent estimation of the AUC: AUC (mg/ml x min) = 0.93 x C3h + 0.47 (MPE% = 4.4%, RMSE% = 8.9%). Furthermore, the two-sample model was shown to improve both the bias and precision of AUC estimation: AUC = 0.16 x C1h + 2.26 x C8h + 0.75 (MPE% = 0.9%, RMSE% = 5.3%). CONCLUSIONS: Our models are useful for future trials to define the accurate relationships between the dose-intensity and effect of carboplatin.

Adenocarcinoma↗

PubMedDate not supplied

Evaluation of curing units used in private dental offices.

It is well known that numerous factors influence the light output of curing units, but many dentists are unaware that the output of their curing lights are inadequate. This study was conducted to evaluate the light intensity of visible-light curing units in private dental offices and to assess their curing efficiency by measuring compressive strength of a light-cured resin. Also, in order to determine the maximum light intensity of the curing units, lamps, filters, and fiber optic bundles were replaced by new ones and curing efficiency remeasured. Light intensity was measured by employing a Quantum Radiometer LI-189 at a wavelength of 470 +/- 40 nm using a bandpass filter. Compressive strength of a light-cured resin using the light units was measured employing an Instron Testing Machine at a crosshead speed of 1.0 mm/min. From the evaluation of 105 light units, the light intensity ranged from 28 to 1368 W/m2 (0 approximately 500 W/m2; 41.9%, 500 approximately 1000 W/ m2; 45.7%, 1000 approximately 1500 W/m2; 12.4%). Light intensity of the light unit in private offices decreased 15.9 approximately 82.1% compared to brand-new units. Reduction of light intensity impaired compressive strength of the light-cured resin to varying degrees (148.3 approximately 279.9 MPa) compared with the highest value (317 MPa) obtained from brand-new light units. The replacement of the parts increased the light intensity, with maximum increases of 36.0% for lamps, 157.7% for filters, 46.2% for fiber optics, and 322.7% for all three parts. The results of this study indicated that the light intensities of the curing units used in private practice were lower than expected.

Composite Resins↗

PubMedDate not supplied

Resin-modified glass ionomers: dentin bond strength versus time.

Most dentin bond strength tests of resin-modified glass-ionomer cements have been conducted after at least 24 hours' storage in water. In a clinical situation, debonding might occur soon after the restoration was placed if subjected to stress. The purpose of this study was to investigate the rate of development of shear bond strength of resin-modified glass-ionomer cements, two Type IIs of which, Fuji II LC and Vitremer, were used. A conventional glass-ionomer cement, Fuji II, and a resin composite, Herculite XRV/OptiBond system, were also employed as controls. Bovine incisors were mounted in self-curing resin, and the facial surfaces wet ground with 600-grit SiC paper to expose dentin. Materials were condensed into a vinyl mold and bonded following the manufacturers' instructions. The shear bond strengths of 10 specimens per group were measured at a crosshead speed of 1.0 mm/minute after 1, 5, 10, 30, and 60 minutes' and 2, 5, and 24 hours' storage in water at 37 degrees C. One-way ANOVAs followed by the Dunnet test (P < 0.05) were used to test for significant differences between the mean bond strength at 1 minute and each of the other test periods. The test period when there was a significant increase in bond strength was defined as the "initial increasing time." The dentin bond strengths of all the materials tested increased with prolonged storage time. The initial increasing times were 10 minutes for Fuji II LC and OptiBond, 20 minutes for Fuji II, and 60 minutes for Vitremer. The differences in the initial increasing time might have clinical implications if the restoration is subjected to significant stress immediately after placement.

Analysis of Variance↗

PubMedDate not supplied

Expression of lung-resistance protein gene is not associated with platinum drug exposure in lung cancer.

BACKGROUND: Platinum drug resistance is an important problem in lung cancer chemotherapy. In this study, we examined lung-resistance protein (LRP) gene expression in vivo and in vitro in relation to platinum drug exposure. MATERIALS AND METHODS: The expression levels of the LRP gene were assessed by the reverse transcription polymerase chain reaction, in 80 autopsy samples (40 lung tumors and 40 corresponding normal lung tissues), two lung cancer cell lines and in peripheral mononuclear cells collected from 8 lung cancer patients before and after platinum drug administration. RESULTS: The LRP gene expression levels of autopsy specimens exposed antemortem to platinum drugs were not significantly different to those of specimens without platinum drug exposure, for both lung tumors and normal lung tissues. Our results also demonstrate that LRP gene expression was not induced by platinum drugs either in vitro or in vivo. CONCLUSIONS: The present results indicate that LRP gene expression is not associated with platinum drug exposure in lung cancer.

Adenocarcinoma↗