Osaka Butsuryo University

In this short review, we have summarized our recent findings about hydrogen water, focusing on the methods for generating hydrogen water, in vivo and in vitro safety tests, and the antioxidant effect and anticancer effect of hydrogen water. Our findings indicate that a portable, inexpensive apparatus for generating hydrogen water in the laboratory is necessary and useful in the field of hydrogen medicine.

Gafchromic EBT3 (EBT3) is used as a radiochromic film in half-value layer (HVL) measurement methods, which are used to calculate the effective energy for QA and QC. HVL measurements using EBT3 display a precision of less than 5 % compared with the results of standard method with an ionization chamber (IC) dosimeter, and offer a simple procedure for determining the HVL consistently and quickly without the need for an IC. However, it is difficult to apply this technique because of the scattered radiation caused by the geometric layout of the X-ray computed tomography (CT) apparatus. In this study, the effect of scattered radiation on EBT3 is investigated. It was found that the EBT3 is not affected by scattered radiation at positions beyond 50 mm from the scattering substance. Therefore, the results suggest that EBT3 is suitable for use in X-ray CT HVL measurements. On the other hand, when the distance from the scattering substance was 10 mm or less, EBT3 showed very high absorption compared to a semiconductor detector. Therefore, EBT3 is more sensitive than the semiconductor detector at a close range and can be used to measure scattered radiation when the distance from the scattering substance is 10 mm or less.

Many studies have suggested that there is a close correlation among declines in internal ascorbic acid (AsA) levels, various disorders, and senescence. To clarify the relationships between age-associated changes in intracellular AsA levels and the effects of AsA administration on intracellular reactive oxygen species (ROS) levels, we investigated aging-related changes in AsA uptake, ROS levels, and the effects of AsA administration on intracellular ROS levels in young and old (senescent) human fibroblasts. Our results demonstrated that AsA uptake was increased in old cells compared with young cells, although mRNA and protein expression of sodium-dependent vitamin C transporter 2 was barely altered between the young and old cells. We also demonstrated that the intracellular superoxide anion level was higher in young cells, whereas the level of intracellular peroxides was significantly increased in old cells under both normal and oxidative stress conditions. Moreover, AsA administration markedly decreased the augmentation of intracellular peroxides in old cells, whereas there was no effect of AsA treatment in young cells under both normal and oxidative stress conditions. Therefore, our results also indicate that AsA could play an important role in regulating the intracellular ROS levels in senescent cells and that the need for AsA is enhanced by cellular senescence.

Our aim in this study was to determine an optimal delay time of hepatic arterial phase (HAP) imaging of hypervascular hepatocellular carcinomas (HCCs) in dynamic contrast-enhanced MDCT (DCE-CT) by use of the bolus-tracking method. The time-enhancement curves (TECs) of the aorta and the contrast of the hepatic arterial and portal system (APC) in the pharmacokinetic analysis were calculated. The clinical study included 41 patients with known or suspected HCC who underwent DCE-CT. The TECs of the aorta and the tumor-liver contrast (TLC) in the clinical study were calculated. On pharmacokinetic analysis, the peak aortic enhancement and the peak APC simulated under conditions of an injection duration of 30 s and an iodine load of 500 mg I/kg body weight were observed 18.5 and 22.5 s, respectively, after the trigger threshold (increased CT value 100 Hounsfield units), respectively. In the clinical study, the peak aortic enhancement and the peak TLC were observed 17.2 and 24.8 s after the trigger threshold, respectively. The optimal delay times until peak aortic enhancement and peak HAP were 15-17 and 19-21 s after the trigger threshold, respectively, under the following conditions: injection dose, 500 mg I/kg body weight; injection duration, 30 s; acquisition time, 5 s; and the trigger threshold. In addition, the peak TLC was achieved 4-7 s after the time to peak aortic enhancement.

The purpose of this study was to investigate the related to swallowing function among chronic stroke patients with dysphagia in nursing home. Using a cross-sectional survey design, the subjects were 60 chronic stroke patients (22 men and 38 women, mean age of 82.6+/-8.3SD) who had given approval for participation in the study. Expert nurses and physical therapists examined swallowing function by Modified Water Swallow Test (MWST) and Repetitive Salvia Swallowing Test (RSST), oral function (oral sense, dry mouth, mouth opening), pulmonary function (respiration, blowing, ability to blow), motor and cognitive function (positioning, range of neck, dementia). There was significant relationship between MWST and RSST (0.64; p<0.01). Multiple linear regression analysis revealed that the independent factors related to MWST were oral sense, dry mouth, and position of chin. These three factors could explain 49% of MWST variance (adjusted R(2)=0.49). The independent factors related to RSST were revealed to be dementia and oral sense. These two factors could explain 44% of RSST variance (adjusted R(2)=0.44). These findings indicate that the independent factors related to reflexive swallowing are different from these related to volitional swallowing. The result of the present study suggested that improvement of oral function is important for promoting reflexive swallowing, and that improvement of cognitive activity is important for promoting volitional swallowing from viewpoint of swallowing rehabilitation for chronic stroke patients.

This paper develops a new numerical procedure for the slope stability analysis, by combining the slice method in the limit equilibrium method with the lower-bound approach in the limit analysis method. The procedure provides an appropriate lower-bound solution subject to the collapse mechanism represented by a potential slip surface. First, the safety factor for the shear strength is calculated for the case in which the position of the slip surface is known beforehand. The problem is formulated as an optimization problem for finding a stress field which minimizes the safety factor within the limitations of satisfying the lower-bound conditions. The formulated problem is solved numerically by the mathematical programming technique. The obtained stress field appears physically reasonable. Several case studies have shown that the simplified Janbu method based on the critical slip surface tends to underestimate the safety factor on the safety side, compared with the lower-bound solution by the proposed procedure. Subsequently, the assumption used in each of the representative slice methods, which are necessary to render the stability problem to a statically determinate, is verified by the use of the stress field determined by the proposed procedure. Finally, a procedure for locating the critical noncircular slip surface which minimizes the safety factor within the lower-bound conditions is developed. Many important properties in the slope stability analysis are clarified through the development of this procedure.