Tomoyasu Nakano
Hamamatsu University
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Featured researches published by Tomoyasu Nakano.
Journal of Nuclear Cardiology | 1997
Chinori Kurata; Sakae Shouda; Tadashi Mikami; Yasushi Wakabayashi; Tomoyasu Nakano; Tsuyoshi Sugiyama; Kei Tawarahara; Kazuyuki Sakata
Background[123I]Metaiodobenzylguanidine (MIBG) imaging has been used to assess cardiac sympathetic nerve abnormalities. We evaluated the clinical significance of myocardial MIBG imaging as a measure of cardiac sympathetic nervous system function by comparing it to heart rate variability and plasma norepinephrine level.Methods and ResultsIn 211 subjects, we analyzed heart rate variability with 24-hour electrocardiography, performed scintigraphy with MIBG, and measured plasma norepinephrine levels. Time and frequency domain measures of heart rate variability were calculated with the Marquette heart rate variability program (Marquette Electronics, Milwaukee, Wis.). Early and late myocardial MIBG uptakes were measured at 15 and 150 minutes after injection, respectively. MIBG clearance rate from the heart and heart-to-lung and heart-to-mediastinum ratios of MIBG activities were calculated. On the whole, heart rate variability, including low-frequency power, correlated positively, but modestly so, with late MIBG uptake and negatively with MIBG clearance rate. The plasma norepinephrine level correlated negatively with late MIBG uptake and with heart rate variability, including low-frequency power, and positively with MIBG clearance rate. Similar correlations were also observed in patient subgroups with coronary artery disease, diabetes mellitus, and renal failure, but these correlations were weak (R2<0.5).ConclusionsIncreased cardiac sympathetic nervous system activity may be associated with increased myocardial MIBG clearance and decreased heart rate variability, including low-frequency power. Because these associations were not strong, however, the combination of heart rate variability with MIBG may allow an interactive assessment of the cardiac autonomic nervous system.
Molecular and Cellular Biochemistry | 2004
Mariko Ozeki; Hiroshi Watanabe; Jinghui Luo; Tomoyasu Nakano; Kazuhiko Takeuchi; Yasuko Kureishi; Masaaki Ito; Takeshi Nakano; Kyoichi Ohashi; Hideharu Hayashi
The protein kinase Akt participates in such important functions of endothelial cells as nitric oxide production and angiogenesis, activities that involve changes in cytosolic Ca2+ concentration. However, it is not known if activation of Akt is itself involved in the regulation of Ca2+ signals produced in these cells. The objective of this study was to examine if Akt is involved in the regulation of Ca2+ signaling in endothelial cells. Agonist-stimulated Ca2+ signals, assessed using fura-2, were compared in porcine aortic endothelial cells under control conditions or conditions in which Akt was blocked either by different inhibitors of phosphatidylinositol 3-kinase (PI3 kinase)/Akt or by transient expression of a dominant-negative form of Akt (dnAkt). We found that the release of intracellular Ca2+ stores stimulated by bradykinin or thapsigargin is not affected by the PI3 kinase inhibitors LY294002 and wortmannin, or by expression of dnAkt. LY294002 dose-dependently inhibits store-operated Ca2+ entry, an effect not seen with wortmannin. Expression of dnAkt has no effect on store-operated Ca2+ entry. We conclude that Akt is not involved in the regulation of agonist-stimulated Ca2+ signals in endothelial cells. The compound LY294002 inhibits store-operated Ca2+ entry in these cells by a mechanism independent of PI3 kinase/Akt inhibition.
Cardiovascular Research | 2006
Tomoyasu Nakano; Hiroshi Watanabe; Mariko Ozeki; Masayoshi Asai; Hideki Katoh; Hiroshi Satoh; Hideharu Hayashi
Journal of Nuclear Cardiology | 2000
Tsuyoshi Sugiyama; Chinori Kurata; Kei Tawarahara; Tomoyasu Nakano
The Journal of Nuclear Medicine | 1997
Chinori Kurata; Yasushi Wakabayashi; Sakae Shouda; Tadashi Mikami; Yasutaka Takei; Kei Tawarahara; Tsuyoshi Sugiyama; Tomoyasu Nakano; Shigeki Fujisawa; Akitada Andoh
Japanese Circulation Journal-english Edition | 2004
Toshihiko Sugi; Hiroshi Satoh; Akihiko Uehara; Hideki Katoh; Hajime Terada; Masaki Matsunaga; Keisuke Yamazaki; Fumitaka Matoh; Tomoyasu Nakano; Shu Yoshihara; Chinori Kurata; Haruo Miyata; Hiroshi Ukigai; Kei Tawarahara; Masahiko Kimura; Shingo Suzuki; Hideharu Hayashi
Japanese Circulation Journal-english Edition | 1998
Chinori Kurata; Sakae Shouda; Tadashi Mikami; Akihiko Uehara; Keiko Ishikawa; Kei Tawarahara; Tomoyasu Nakano; Fumitaka Matoh; Kazuhiko Takeuchi
Molecular and Cellular Biochemistry | 2004
Mariko Ozeki; Hiroshi Watanabe; Jinghui Luo; Tomoyasu Nakano; Kazuhiko Takeuchi; Yasuko Kureishi; Masaharu Ito; Takeshi Nakano; Kyoichi Ohashi; Hideharu Hayashi
Japanese Journal of Electrocardiology | 2016
Seiko Mizuno; Masaki Matsunaga; Yusaku Mochizuki; Kazue Yaginuma; Keisuke Iguchi; Katsunori Shiraki; Tomoyasu Nakano
Japanese Circulation Journal-english Edition | 2006
Fumitaka Matoh; Takeji Saitoh; Yasuyo Takeuchi; Keiichi Odagiri; Hirotaka Kawashima; Hiromutsu Tominaga; Masayoshi Asai; Saori Matsui; Shiro Nagasaka; Katsunori Shiraki; Tomoyasu Nakano; Kazuhiko Takeuchi; Tsuyoshi Urushida; Hideki Katou; Hiroshi Satoh; Hideharu Hayashi; Yasuo Takehara