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Search Results: 1 - 10 of 893 matches for " Hirotaka Shimada "
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Efforts to Improve the Images from 67Ga Whole-Body Scintigraphy  [PDF]
Kyoko Saito, Yasuyuki Takahashi, Naomi Ogano, Hirotaka Shimada, Takao Kanzaki, Hiroki Okada, Kei Yokota, Kaori Hatano, Yuki Yoshida, Tetsuya Higuchi
World Journal of Nuclear Science and Technology (WJNST) , 2015, DOI: 10.4236/wjnst.2015.51001
Abstract: The acquisition method for planar 67Ga imaging has hardly changed for 30 years. In this study, in order to improve image quality and diagnostic accuracy, we take steps to optimize the acquisition method, and to choose a scatter correction. First, we acquired individual images from the 93 keV, 185 keV, and 300 keV photopeak; then the images were added together and compared to the individual images. Second, we compared results from a low-medium-energy (LME) collimator with those from a conventional medium-energy (ME) collimator. Also, we examined whether to combine the data from all three of the usual window locations (set about 93 keV, 185 keV, and 300 keV) or to use the data from only two. Third, we compared results from a conventional photopeak ± 10 window with those from a photopeak ± 9 keV window. Fourth, for scatter correction we compared results using the triple energy window (TEW) method with those using the multi-photopeak dual window (MDW) method. The phantoms studied were cold rods in a uniform background, and hot spheres within a cylinder containing uniformly radioactive water. The clinical study involved 22 patients with lung lesions. By the comparison by the contrast ratio in cold rods phantom, 15.6% is improved in LME (2 peaks) than ME (3 peaks), and 3.2% is improved in photopeak ± 9 keV than photopeak ± 10%, 10.2% is improved in TEW than MDW. However, the TEW scatter correction method recognized unstable to the contrast ratio in a clinical study. In addition, a body outline might disappear.
Sleep Duration and Overweight among Elementary Schoolchildren:A Population-based Study in Japan
Ochiai,Hirotaka,Shirasawa,Takako,Shimada,Naoki,Ohtsu,Tadahiro
Acta Medica Okayama , 2012,
Abstract: Although a number of studies have investigated the relationship of sleep duration to overweight and obesity, studies conducted among population-based elementary schoolchildren have been limited in Japan. The aim of the present study was to investigate the relationship between sleep duration and overweight among elementary schoolchildren in Japan. The study subjects were all fourth-grade schoolchildren (9 or 10 years of age) in Ina-town, Saitama Prefecture, Japan from 1999 to 2008. Information concerning each subject s sex, age, and lifestyle was obtained using a self-administered questionnaire, while measurements of his or her height and weight were carried out. Childhood overweight was determined according to the definition established by the International Obesity Task Force. Data from 3,433 children were analyzed. In logistic regression analysis, a statistically significant dose-response relationship was observed between sleep duration and overweight among boys (p for trend=0.014) but not among girls (p for trend=0.149). Short sleep duration was associated with childhood overweight, and the sex difference in the association was observed. These findings suggested that it is important to consider sleep duration as part of any program to prevent overweight among elementary schoolchildren, especially among boys.
Eating Behavior and Childhood Overweight Among Population-Based Elementary Schoolchildren in Japan
Hirotaka Ochiai,Takako Shirasawa,Rimei Nishimura,Aya Morimoto,Naoki Shimada,Tadahiro Ohtsu,Masayasu Hashimoto,Hiromi Hoshino,Naoko Tajima,Akatsuki Kokaze
International Journal of Environmental Research and Public Health , 2012, DOI: 10.3390/ijerph9041398
Abstract: This study investigated the relationship between eating behavior and childhood overweight among population-based elementary schoolchildren in Japan. Data was collected from fourth graders (9 or 10 years of age) from Ina Town, Saitama Prefecture, Japan from 1999 to 2009. Information about subjects’ sex, age, and lifestyle, including eating behaviors (eating until full and chewing thoroughly), was obtained using a self-administered questionnaire, and height and weight were measured directly. Overweight was determined according to the definition established by the International Obesity Task Force. Data from 4027 subjects (2079 boys and 1948 girls) were analyzed. Chewing thoroughly was associated with a significantly decreased odds ratio (OR) for being overweight, whereas eating until full significantly increased the OR for being overweight (OR: 1.50, 95% confidence interval: 1.16–1.94) among boys. However, eating until full was not associated with a significantly increased OR for being overweight among the group that reported chewing thoroughly, whereas it was associated with a significantly increased OR for being overweight (2.02, 1.38–2.94) among boys who did not chew thoroughly. In conclusion, eating until full or not chewing thoroughly was associated with being overweight among elementary schoolchildren. Results of this study suggest that chewing thoroughly may be an avenue to explore childhood overweight prevention efforts.
Relationship of body mass index to percent body fat and waist circumference among schoolchildren in Japan - the influence of gender and obesity: a population-based cross-sectional study
Hirotaka Ochiai, Takako Shirasawa, Rimei Nishimura, Aya Morimoto, Naoki Shimada, Tadahiro Ohtsu, Emiko Kujirai, Hiromi Hoshino, Naoko Tajima, Akatsuki Kokaze
BMC Public Health , 2010, DOI: 10.1186/1471-2458-10-493
Abstract: Subjects included 3,750 schoolchildren from the fourth and seventh grade in Ina-town, Saitama Prefecture, Japan between 2004 and 2008. Information about subject's age, sex, height, weight, %BF, and WC was collected from annual physical examinations. %BF was measured with a bipedal biometrical impedance analysis device. Obesity was defined by the following two criteria: the obese definition of the Centers for Disease Control and Prevention, and the definition of obesity for Japanese children. Pearson's correlation coefficients between BMI and %BF or WC were calculated separately for sex.Among fourth graders, the correlation coefficients between BMI and %BF were 0.74 for boys and 0.97 for girls, whereas those between BMI and WC were 0.94 for boys and 0.90 for girls. Similar results were observed in the analysis of seventh graders. The correlation coefficient between BMI and %BF varied by physique (obese or non-obese), with weaker correlations among the obese regardless of the definition of obesity; most correlation coefficients among obese boys were less than 0.5, whereas most correlations among obese girls were more than 0.7. On the other hand, the correlation coefficients between BMI and WC were more than 0.8 among boys and almost all coefficients were more than 0.7 among girls, regardless of physique.BMI was positively correlated with %BF and WC among Japanese schoolchildren. The correlations could be influenced by obesity as well as by gender. Accordingly, it is essential to consider gender and obesity when using BMI as a surrogate for %BF and WC for epidemiological use.Obesity in childhood increases the risk of obesity in adulthood and is associated with cardiovascular disease (CVD) risk factors [1]. Therefore, childhood obesity should be closely monitored.The ideal definition of child obesity, based on percent body fat (%BF), is impracticable for epidemiological use [2] because a special device, which is not always available, is needed to measure %BF. Although w
Joint effect of longevity-associated mitochondrial DNA 5178 C/A polymorphism and alcohol consumption on risk of hyper-LDL cholesterolemia in middle-aged Japanese men
Teruyoshi Kawamoto, Akatsuki Kokaze, Mamoru Ishikawa, Naomi Matsunaga, Kanae Karita, Masao Yoshida, Naoki Shimada, Tadahiro Ohtsu, Takako Shirasawa, Hirotaka Ochiai, Taku Ito, Hiromi Hoshino, Yutaka Takashima
Lipids in Health and Disease , 2011, DOI: 10.1186/1476-511x-10-105
Abstract: A total of 394 male subjects were selected from among individuals visiting the hospital for regular medical check-ups. After Mt5178 C/A genotyping, a cross-sectional study assessing the combined effect of Mt5178 polymorphism and alcohol consumption on the risk of dyslipidemia was conducted.For men with Mt5178C, alcohol consumption was significantly and negatively associated with the risk of hyper-low-density lipoprotein (LDL) cholesterolemia (serum LDL cholesterol ≥ 140 mg/dl) (P for trend = 0.015). After adjustment for age, body mass index (BMI), habitual smoking, coffee consumption and use of antihypertensive medicine, the odds ratio (OR) for hyper-LDL cholesterolemia was significantly lower in daily drinkers with Mt5178C than non-drinkers with Mt5178C (OR = 0.360, 95% confidence intervals: 0.153-0.847). A significant and negative association between alcohol consumption and serum LDL cholesterol levels was also observed in Mt5178C genotypic men (P for trend < 0.01). On the other hand, the association between Mt5178A genotype and risk of hyper-LDL cholesterolemia does not appear to depend on alcohol consumption.For Mt5178C genotypic men, alcohol consumption may reduce the risk of hyper-LDL cholesterolemia.Mitochondrial DNA 5178 (Mt5178) C/A polymorphism, also known as NADH dehydrogenase subunit-2 237 (ND2-237) Leu/Met, is a longevity-associated mitochondrial DNA polymorphism [1-3]. The frequency of the Mt5178A genotype is significantly higher in Japanese centenarians than in the general population [1]. Japanese individuals with Mt5178A are more resistant to lifestyle-related adult-onset diseases, such as hypertension [4], diabetes [5], myocardial infarction [6,7] and cerebrovascular disorders [8], than those with Mt5178C. This polymorphism is also associated with serum lipid levels [9] and fasting plasma glucose levels [10].A combined effect of Mt5178 C/A polymorphism and alcohol consumption on serum lipid levels has been reported [11]. Alcohol consumption is negat
Association between Myocardial Triglyceride Content and Cardiac Function in Healthy Subjects and Endurance Athletes
Eiryu Sai, Kazunori Shimada, Takayuki Yokoyama, Shuji Sato, Tetsuro Miyazaki, Makoto Hiki, Yoshifumi Tamura, Shigeki Aoki, Hirotaka Watada, Ryuzo Kawamori, Hiroyuki Daida
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0061604
Abstract: Ectopic fat accumulation plays important roles in various metabolic disorders and cardiovascular diseases. Recent studies reported that myocardial triglyceride (TG) content measured by proton magnetic resonance spectroscopy (1H-MRS) is associated with aging, diabetes mellitus, and cardiac dysfunction. However, myocardial TG content in athletes has not yet been investigated. We performed 1H-MRS and cardiac magnetic resonance imaging in 10 male endurance athletes and 15 healthy male controls. Serum markers and other clinical parameters including arterial stiffness were measured. Cardiopulmonary exercise testing was also performed. There were no significant differences in clinical characteristics including age, anthropometric parameters, blood test results, or arterial stiffness between the two groups. Peak oxygen uptakes, end–diastolic volume (EDV), end–systolic volume (ESV), left ventricular (LV) mass, peak ejection rates and peak filling rates were significantly higher in the athlete group than in the control group (all P<0.02). Myocardial TG content was significantly lower in the athlete group than in the control group (0.60±0.20 vs. 0.89±0.41%, P<0.05). Myocardial TG content was negatively correlated with EDV (r = ?0.47), ESV (r = ?0.64), LV mass (r = ?0.44), and epicardial fat volume (r = 0.47) (all P<0.05). In conclusion, lower levels of myocardial TG content were observed in endurance athletes and were associated with morphological changes related to physiological LV alteration in athletes, suggesting that metabolic imaging for measurement of myocardial TG content by 1H-MRS may be a useful technique for noninvasively assessing the “athlete’s heart”.
Adipose Tissue-Derived Mesenchymal Stem Cells in Long-Term Dialysis Patients Display Downregulation of PCAF Expression and Poor Angiogenesis Activation
Shuichiro Yamanaka, Shinya Yokote, Akifumi Yamada, Yuichi Katsuoka, Luna Izuhara, Yohta Shimada, Nobuo Omura, Hirotaka James Okano, Takao Ohki, Takashi Yokoo
PLOS ONE , 2014, DOI: 10.1371/journal.pone.0102311
Abstract: We previously demonstrated that mesenchymal stem cells (MSCs) differentiate into functional kidney cells capable of urine and erythropoietin production, indicating that they may be used for kidney regeneration. However, the viability of MSCs from dialysis patients may be affected under uremic conditions. In this study, we isolated MSCs from the adipose tissues of end-stage kidney disease (ESKD) patients undergoing long-term dialysis (KD-MSCs; mean: 72.3 months) and from healthy controls (HC-MSCs) to compare their viability. KD-MSCs and HC-MSCs were assessed for their proliferation potential, senescence, and differentiation capacities into adipocytes, osteoblasts, and chondrocytes. Gene expression of stem cell-specific transcription factors was analyzed by PCR array and confirmed by western blot analysis at the protein level. No significant differences of proliferation potential, senescence, or differentiation capacity were observed between KD-MSCs and HC-MSCs. However, gene and protein expression of p300/CBP-associated factor (PCAF) was significantly suppressed in KD-MSCs. Because PCAF is a histone acetyltransferase that mediates regulation of hypoxia-inducible factor-1α (HIF-1α), we examined the hypoxic response in MSCs. HC-MSCs but not KD-MSCs showed upregulation of PCAF protein expression under hypoxia. Similarly, HIF-1α and vascular endothelial growth factor (VEGF) expression did not increase under hypoxia in KD-MSCs but did so in HC-MSCs. Additionally, a directed in vivo angiogenesis assay revealed a decrease in angiogenesis activation of KD-MSCs. In conclusion, long-term uremia leads to persistent and systematic downregulation of PCAF gene and protein expression and poor angiogenesis activation of MSCs from patients with ESKD. Furthermore, PCAF, HIF-1α, and VEGF expression were not upregulated by hypoxic stimulation of KD-MSCs. These results suggest that the hypoxic response may be blunted in MSCs from ESKD patients.
Socially Anxious Tendencies Affect Autonomic Responses during Eye Gaze Perception  [PDF]
Yuki Tsuji, Sotaro Shimada
Psychology (PSYCH) , 2015, DOI: 10.4236/psych.2015.613160
Abstract: Social anxiety disorder is a common psychiatric disorder. The gaze of others is known to frequently induce social anxiety. We conducted a gaze detection experiment to examine the effects of social anxiety on autonomic response, namely heart rate (HR) response. We used the maximum HR deceleration between 0 s and 3 s after stimulus onset as an indicator of emotional stress. Participants were assigned to a high social anxiety (HSA) or low social anxiety (LSA) group on the basis of cut-off scores indicative of clinical levels of stress as per the Japanese version of the Liebowitz Social Anxiety Scale (LSAS-J). Our results showed that HR deceleration was greater for the HSA compared with the LSA group. Moreover, the higher the LSAS-J score was, the greater the increase was in HR deceleration (correlation coefficient rs = 0.52, p < 0.01). Our results suggest that the eye gaze of others can be processed as a threat in individuals with a high tendency towards social anxiety.
Detailed Mechanism and Engineering Applicability of Electrolytic Polymerization Aided by a Magnetic Field in Natural Rubber by Mechanical Approach for Sensing (Part 1): The Effect of Experimental Conditions on Electrolytic Polymerization  [PDF]
Kunio Shimada, Norihiko Saga
World Journal of Mechanics (WJM) , 2016, DOI: 10.4236/wjm.2016.610026
Abstract: Ordinary electrolytic polymerization has involved plastic-type polymer solutions. Rubber, especially natural rubber, is one such polymer solution. Rubber has not been focused on until recently due to the fact that electrolytic polymerization has only a very small effect on rubber. However, when we focus on the C=C bonds of natural rubber, the same electrolytic polymerization is applicable to be enlarged on the natural rubber if a magnetic field and a filler are added. With the application of a magnetic field and a magnetic responsive fluid such as magnetic compound fluid (MCF), the effect of electrolytic polymerization on NR-latex such as plastic-type polymer solutions is enhanced, and the thickness of the vulcanized MCF rubber grows in a short time. The present new method of vulcanization of MCF rubber is effective enough that it is widely used in haptic sensors in various engineering applications. In the present report, as mechanical approach for the sensing, by measuring the temperature under electrolytic polymerization, by investigating the electric and dynamic characteristics, and by observing the magnified appearance of the MCF rubber, we clarified the extrinsic effects of many experimental conditions, including magnetic field strength, applied voltage, the electrodes gap, mass concentration, and the ingredients of the MCF. This report is Part 1, to be followed by another sequential report, Part 2, in which other intrinsic effects on the characteristics are dealt with. The experimental conditions used and the results obtained in the present report provide valuable data that will be useful in the making of MCF rubber.
Detailed Mechanism and Engineering Applicability of Electrolytic Polymerization Aided by a Magnetic Field in Natural Rubber by Mechanical Approach for Sensing (Part 2): Other and Intrinsic Effects on MCF Rubber Property  [PDF]
Kunio Shimada, Norihiko Saga
World Journal of Mechanics (WJM) , 2016, DOI: 10.4236/wjm.2016.610027
Abstract: The same ordinary electrolytic polymerization of plastic-type polymer solution is applicable to natural rubber, with its C=C bonds, if a magnetic field and a filler are added. With the application of a magnetic field and the magnetic responsive fluid known as magnetic compound fluid (MCF), we have clarified the enhancement of the electrolytic polymerization of NR-latex and the growth of the thickness of vulcanized MCF rubber that results from the addition of a magnetic field. The present new method of MCF rubber vulcanization is effective for use in haptic sensors, which are used widely in various engineering applications. In the previous report, part 1 of this study, we investigated many experimental conditions under mechanical approach for sensing: magnetic field strength; applied voltage; electrodes gap; mass concentration, and the ingredients of the MCF. In the present sequential report, part 2, we investigate many other effects on electrolytic polymerization by the same mechanical approach for sensing as in part 1: the Mullins effect; the Piezo effect; vibration; kind of electrode; atmospheric gas. In particular, we clarify that the voltage generates spontaneously in the MCF rubber and that the MCF rubber becomes a Piezo element. These effects on the electrolytic polymerization as well as the effects of the experimental conditions will be useful in engineering applications. By taking the above-mentioned parameters and effects into account, MCF rubber that is electrolytically polymerized with the aid of a magnetic field, the use of MCF as a filler, and doping, can be useful in haptic sensor applications. In particular, the effectiveness of the Piezo element can be shown.
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