Tetsuji Nozaki
Tohoku University
Network
Latest external collaboration on country level. Dive into details by clicking on the dots.
Publication
Featured researches published by Tetsuji Nozaki.
Cardiovascular Pathology | 2001
Tetsuji Nozaki; Yutaka Kagaya; Nobumasa Ishide; Shuichi Kitada; Masahito Miura; Jun Nawata; Isao Ohno; Jun Watanabe; Kunio Shirato
We hypothesized that the mitochondrial length may be altered according to changes in the sarcomere length, and that this relationship may be affected by exposure to hypoxia. Rat ventricular papillary muscles were isolated and immersed in normoxic or hypoxic solutions for 10 min. Sarcomeres of various lengths were obtained by fixing the papillary muscles in a slack or stretched state, or after exposure to a contracture solution containing saponin and CaCl(2). The mitochondrial length measured using electron microscopy significantly correlated to the length of the adjacent sarcomere in both the normoxic (n=767) and hypoxic (n=1145) groups (P<.0001). The slope of the regression line, however, was significantly less steep, and its intercept was significantly larger in the hypoxic group than in the normoxic group (analysis of covariance). When we analyzed the mitochondrial lengths among the three sarcomere-length subgroups (<1.5, 1.5-2.0, and >2.0 microm), the mitochondrial length was significantly shorter in the hypoxic condition than in the normoxic condition at sarcomere lengths greater than 2.0 microm. Staining for desmin, the major muscle-type intermediate filament, the longitudinal system of which connects the mitochondria with the Z bands of sarcomeres, showed a clear cross-striation pattern in both papillary muscles with and without the exposure to hypoxia, suggesting that desmin was preserved after the exposure to hypoxia. These data indicate that the mitochondrial length changes according to changes in the sarcomere length, suggesting the possible role of mitochondria as an internal load against myocyte contraction. It is also suggested that mitochondria exposed to hypoxia may be more resistive to both compression and stretch in a longitudinal direction than those in the normoxic condition.
American Journal of Physiology-heart and Circulatory Physiology | 1998
Yuriko Yamane; Nobumasa Ishide; Yutaka Kagaya; Daiya Takeyama; Nobuyuki Shiba; Masanobu Chida; Tetsuji Nozaki; T. Takahashi; Tatsuo Ido; Kunio Shirato
We determined whether spatial distributions of substrate uptake are heterogeneous within the area at risk during reperfusion. Quantitative autoradiography with imaging plates and two long-lived radioisotopes was applied to 15 open-chest, anesthetized rats subjected to 30 min of coronary artery ligation and 30 min of reperfusion. Regions showing increased beta-methyl-[1-14C]heptadecanoic acid ([14C]BMHDA) uptake (166 +/- 17% of that in the nonischemic area) appeared at the lateral borders and subepicardial layer within the area at risk, and 2-deoxy-D-[1-3H]glucose ([3H]DG) uptake was 103 +/- 24% in these regions. Regions with decreased [14C]BMHDA uptake (28 +/- 11%) occupied the midmyocardial layer except at the lateral borders within the area at risk, and [3H]DG uptake was 62 +/- 18% in these regions. The percentage interregional coefficients of variation (index of heterogeneity) in [14C]BMHDA uptake, [3H]DG uptake, and blood flow were higher in the area at risk than in the nonischemic area (76 +/- 23 vs. 21 +/- 7%, 39 +/- 10 vs. 21 +/- 7%, and 49 +/- 19 vs. 14 +/- 4%, respectively). Heterogeneous distributions of substrate uptake may explain the conflicting results concerning substrate metabolism during reperfusion.We determined whether spatial distributions of substrate uptake are heterogeneous within the area at risk during reperfusion. Quantitative autoradiography with imaging plates and two long-lived radioisotopes was applied to 15 open-chest, anesthetized rats subjected to 30 min of coronary artery ligation and 30 min of reperfusion. Regions showing increased β-methyl-[1-14C]heptadecanoic acid ([14C]BMHDA) uptake (166 ± 17% of that in the nonischemic area) appeared at the lateral borders and subepicardial layer within the area at risk, and 2-deoxy-d-[1-3H]glucose ([3H]DG) uptake was 103 ± 24% in these regions. Regions with decreased [14C]BMHDA uptake (28 ± 11%) occupied the midmyocardial layer except at the lateral borders within the area at risk, and [3H]DG uptake was 62 ± 18% in these regions. The percentage interregional coefficientsof variation (index of heterogeneity) in [14C]BMHDA uptake, [3H]DG uptake, and blood flow were higher in the area at risk than in the nonischemic area (76 ± 23 vs. 21 ± 7%, 39 ± 10 vs. 21 ± 7%, and 49 ± 19 vs. 14 ± 4%, respectively). Heterogeneous distributions of substrate uptake may explain the conflicting results concerning substrate metabolism during reperfusion.
The Journal of Nuclear Medicine | 1995
Yuriko Yamane; Nobumasa Ishide; Yutaka Kagaya; Daiya Takeyama; Nobuyuki Shiba; Masanobu Chida; Yohei Sekiguchi; Tetsuji Nozaki; Tatsuo Ido; Kunio Shirato
The Journal of Nuclear Medicine | 1997
Yuriko Yamane; Nobumasa Ishide; Yutaka Kagaya; Daiya Takeyama; Nobuyuki Shiba; Masanobu Chida; Tetsuji Nozaki; T. Takahashi; Tatsuo Ido; Kunio Shirato
Archive | 2013
Masanobu Chida; Tetsuji Nozaki; Toshihiro Takahashi; T. Ido; Kunio Shirato; Yuriko Yamane; Nobumasa Ishide; Yutaka Kagaya; Daiya Takeyama; Nobuyuki Shiba
Shinzo | 2007
Tohru Takahashi; Masanobu Miura; Masateru Kondo; Yutaka Minatoya; Koichi Hanada; Chikako Takahashi; Takuya Yagi; Tetsuji Nozaki; Eiji Nozaki; Kenji Tamaki
Japanese Circulation Journal-english Edition | 2006
Tohru Takahahshi; Maki Hosoya; Chikako Takahashi; Takuya Yagi; Tetsuji Nozaki; Eiji Nozaki; Kenji Tamaki
Japanese Circulation Journal-english Edition | 2004
Takuya Yagi; Osamu Kitamukai; Sunao Toda; Tetsuji Nozaki; Yoshito Yamamoto; Eiji Nozaki; Kenji Tamaki; Kunio Shirato
Japanese Circulation Journal-english Edition | 2004
Sunao Toda; Masahiro Iwabuchi; Osamu Kitamukai; Takuya Yagi; Tetsuji Nozaki; Yoshito Yamamoto; Eiji Nozaki; Kenji Tamaki; Jun Watanabe; Kunio Shirato
Japanese Circulation Journal-english Edition | 2002
Hideaki Endo; Shu Suzuki; Tetsuji Nozaki; Yoshito Yamamoto; Hidenari Houzawa; Hiroyuki Oura; Eiji Nozaki; Kenji Tamaki; Kunio Shirato