<ORIGINAL ARTICLE>ESR spin trapping study on ascorbic acid as a scavenger of hydroxyl and hydrogen radicals

The present study was carried out to confirm the usefulness of the ESR spin trapping technique for detecting and measuring short-lived radicals and to clarify the ability of ascorbic acid as a radical scavenger against radicals generated from irradiated human serum. One hundred μl of human serum was irradiated with 1 Gy of X-ray radiation coexisting with 35 μl of DETAPAC, 50 μl of various concentrations (2×10^M～60×10^M) of ascorbic acid, and 15 μl of DMPO. After irradiation at each concentration, the ESR signals were recorded using an ESR spectrometer. These signals were identified, and then normalized as the relative signal intensities against the standard signal intensity of manganese oxide marker. The relative signal intensities were plotted, and the results showed that the signals were from DMPO-OH and DMPO-H, showing the generation of ・OH and ・H, and that the relative signal intensities obtained at each concentration decreased as the concentration of ascorbic acid increased

Advantage of Recording Single-Unit Muscle Sympathetic Nerve Activity in Heart Failure

Elevated sympathetic activation is a characteristic feature of heart failure (HF). Excessive sympathetic activation under resting conditions has been shown to increase from the early stages of the disease, and is related to prognosis. Direct recording of multiunit efferent muscle sympathetic nerve activity (MSNA) by microneurography is the best method for quantifying sympathetic nerve activity in humans. To date, this technique has been used to evaluate the actual central sympathetic outflow to the periphery in HF patients at rest and during exercise; however, because the firing occurrence of sympathetic activation is mainly synchronized by pulse pressure, multiunit MSNA, expressed as burst frequency (bursts/min) and burst incidence (bursts/100 heartbeats), may have limitations for the quantification of sympathetic nerve activity. In HF, multiunit MSNA is near the maximum level, and cannot increase further than the heartbeat. Single-unit MSNA analysis in humans is technically demanding, but provides more detailed information regarding central sympathetic firing. Although a great deal is known about the response of multiunit MSNA to stress, little information is available regarding the responses of single-unit MSNA to physiological stress and disease. The purposes of this review are to describe the differences between multiunit and single-unit MSNA during stress and to discuss the advantages of single-unit MSNA recording in improving our understanding the pathology of increased sympathetic activity in HF

<ORIGINAL>Microradiography in the differentiation and definite diagnosis of odontomas

The present study evaluated the usefulness of microradiography in differentiny and making a definite diagnosis of odontomas. A surgically removed odontoma from a 14-year-old girl was used here. The specimen was sectioned at approximately 100μm thickness and ground to 50μm. Microradiographic images were obtained using soft X-ray equipment (Sofron, Japan) under the conditions of : tube voltage, 10kVp ; tube current, 5mA ; FSD 7.5cm ; and exposure time, 20min. The images were evaluated by comparing to images obtained by histological procedures. The results showed that the microradiographic images had almost the same resolution as that of the microscopic images

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Kodak社製のUltraspeed歯科用X線フィルム2種類とEktaspeed歯科用X線フィルム2種類について,それぞれの特性曲線をtime scaling法により描いた。結果としては,Ektaspeedグループの特性曲線は,各測定管電圧においてほぼ同一の曲線を示したが,Ultraspeedグループの特性曲線は異っていた。この違いの原因は,各フィルムのフィルムベースもしくは乳剤,あるいはその両方の違いにあることが想像された。The characteristic curves obtained from two types of the Kodak Ultraspeed dental X-ray films and two types of the Kodak Ektaspeed dental X-ray films were drawn by means of time scaling method. The Ektaspeed group showed almost the same curves at each observed tube voltage, but those of the Ultraspeed group were different from one another. It was expected that the origin of this difference might be caused by the differences of the film base and/or emulsion of each film

<ORIGINAL>A prospective randomized clinical study on the efficacy of CO_2 lasers on initial stage endodontics

The purpose of this study was to evaluate the clinical efficacy of the CO_2 laser in a prospective randomized trial. A total of 112 teeth in 112 patients, previously treated pulpectomy procedures were gathered and randomly divided into two groups composed of 56. Irradiation was performed on one group and non-irradiation forms of treatment were performed on the other group. On the first group of teeth, root canal enlargement was done and followed by exposure of the canal to a CO_2 laser light (5W, 200msec) using 3 cycles each at a rate of 15 seconds per cycle. The second group was not exposed to laser light following root canal enlargement. The laser was applied on the root canal for a controlled period of time. On the day following pulpectomy, a statistically significant (p < 0.05) fewer number of patients observed pain in the irradiation group compared to the non-irradiation group. The treatment times and the total treatment days in the irradiation group are shorter than in the non-irradiation group (p < 0.05). Multivariate analysis showed that the laser treatment was significantly associated with treatment times. This study shows that the degree of oral pain was greatly reduced in patients who underwent laser irradiation as compared to these who did not. Our study suggests that the use of laser treatment provide significant short-term improvement compared to conventional forms of treatment performed during pulpectomy