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Biomedical subjects

H Otani

Publications and source records attributed to H Otani.

At least 235 records · Page 13Linked to original sources
PubMed1984

In vitro study on contribution of oxidative metabolism of isolated rabbit heart mitochondria to myocardial reperfusion injury.

The present study was performed to clarify oxygen-induced damage following myocardial reperfusion, using three mitochondrial preparations from isolated rabbit hearts (nonischemic hearts and those subjected to 40 and 90 minutes of normothermic global ischemia). The viability of mitochondria was evaluated by adenosine triphosphate generation. The extent of mitochondrial injury produced by reactive oxygen metabolism was assessed by the intensity of hydroxyl radical signal detected with electron spin resonance spectroscopy and the reduction of coenzyme Q10 level. The greatest oxygen-induced injury was observed in 40-minute ischemic mitochondria exposed to pure oxygen. The use of superoxide dismutase and catalase satisfactorily prevented the oxygen-induced injury. Moreover, the net adenosine triphosphate generation of the 40-minute ischemic mitochondria was comparable to that of the nonischemic mitochondria without the enzymes. These results suggest that reperfusion of the ischemic myocardium with viable mitochondria is deleterious, because mitochondria are susceptible to injury resulting from oxidative metabolism, and that the use of superoxide dismutase, together with catalase, is beneficial for the restoration of cardiac function after ischemia.

Adenosine Triphosphate↗
PubMed1981

Sensitivity in detection of monoclonal immunoglobulins by thin-layer isoelectric focusing and certain electrophoreses in laboratory use.

By applying sera containing various myeloma proteins to thin-layer isoelectric focusing at various pH ranges, we found that the best range of pH gradient for the detection of the band group specific for monoclonal immunoglobulin was from 5 to 8. The lowest concentration of monoclonal immunoglobulin detected by this method was approximately 0.1 mg/ml which was 8 to 32 times lower than the concentration detectable by cellulose acetate membrane electrophoresis or immunoelectrophoresis in routine laboratory use. Monoclonal protein concentration from 0.1 to 20 mg/ml was determined quantitatively. Blind tests on sera resulted in a disagreement between the concentration of monoclonal immunoglobulin assumed from the results of cellulose acetate membrane electrophoresis and immunoelectrophoresis and that determined by isoelectric focusing. These results suggest that isoelectric focusing is useful for the surveillance of monoclonal immunoglobulinemia provided that the technique and equipment are improved for laboratory tests.

Electrophoresis, Cellulose Acetate↗
PubMed1981

Porosity--strength relationship in a Cu-rich spherical alloy amalgam.

Porosity and strength of spherical Cu-rich alloy amalgams were analyzed in the under-graduate materials laboratory. The minimum value for porosity was obtained for 46% initial Hg content, whereas the maximum strengths were obtained for 42% initial Hg. This result did not coincide with the data previously obtained for the conventional spherical alloy amalgam, in which the maximum strength and the minimum porosity were strictly associated with the optimum initial Hg content. Although no critical value for porosity could be definitely demonstrated by this effort, this result may be an indirect indication for 4.5 vol% porosity as the critical value.

Copper↗
PubMed1979

[Retention of crowns as affected by film thickness of zinc phosphate cement and taper angle of crowns (author's transl)].

Dependence of the retention of crowns at their axial wall on the film thickness of zinc phosphate cement and the taper angle was investigated. Stainless steel dies, composed of a preparation and an occlusally perforated crown the taper angle of which was 2.9, 5.7, 8.5 and 11.3 degrees respectively (Fig. 1, (a) and (b)), were cemented within three min. after the start of mix with a Shofu Micro Cement having a powder-liquid ratio of 1.5 g/0.5 cc. The thickness of the cement layer at the axial wall was regulated to a given value between 9 and 55 mu through the use of a discrepancy measurer. A Shimazu Autograph tensile test machine was employed to measure 48-hr retention (kg/cm2). The retention of the crowns was strongly dependent on the cement film thickness and the taper angle when the film thickness was below a critical value (15 mu in this experiment), but not when the film thickness was above this value (Fig. 3). This may be explained by the term of mechanical interlocking of either of the unreacted powder grains and the matrix phase in the luting cement, as schematically drawn in Fig. 6. The same findings were more evidently appeared on the semilogarythmic diagram in Fig. 4. In this diagram, the critical value was shown as intersection of two straight lines which could be drawn through all the measurements for four taper angles, using the least squares.

Crowns↗