- 著者
- Takahiro Tokuhisa Masafumi Yano Masakazu Obayashi Toshiyuki Noma Mamoru Mochizuki Tetsuro Oda Shinichi Okuda Masahiro Doi Jinyao Liu Yasuhiro Ikeda Takeshi Yamamoto Tomoko Ohkusa Masunori Matsuzaki
- 出版者
- The Japanese Circulation Society
- 雑誌
- Circulation Journal (ISSN:13469843)
- 巻号頁・発行日
- vol.70, no.6, pp.777-786, 2006 (Released:2006-05-25)
- 参考文献数
- 42
- 被引用文献数
- 18 20
Background The Ca2+ regulatory proteins in the sarcoplasmic reticulum (SR) play a key role in the pathogenesis of heart failure. In the present study the effect of chronic β-receptor-stimulation on cardiac and SR functions was assessed, with or without angiotensin-II receptor antagonist treatment recently reported to have anti-β-adrenergic activity. Methods and Results Rats were treated with isoproterenol with (+) or without (-) candesartan (CAN) and then SR vesicles were isolated from the left ventricular muscle. Both Ca2+-uptake and the amount of SR Ca2+-ATPase were significantly lower in the CAN (-) group than in the shams, but those were almost normally restored in the CAN (+). Although the level of the protein kinase A (PKA)-phosphorylation of the SR Ca2+ release channel, known as the ryanodine receptor (RyR2), was elevated in the CAN (-), no Ca2+-leak was detected. However, SIN-1 (O2 - donor) induced Ca2+-leak in the CAN (-) at a 10-fold lower dose than in the sham and CAN (+). In cardiomyocytes, SIN-1 decreased cell shortening and the peak Ca2+ transient and prolonged time from peak to 70% decline in CAN (-), again at 10-fold lower dose than in the sham and CAN (+). Conclusion Chronic β-receptor-stimulation did not induce any Ca2+-leak from the SR, whereas Ca2+-leak was easily induced when oxidative stress was applied to the PKA-phosphorylated RyR2. Candesartan not only improved Ca2+-uptake, but also prevented PKA-phosphorylation, rendering the SR less susceptible to Ca2+-leak. (Circ J 2006; 70: 777 - 786)
- 著者
- Yasuaki Wada Kazuya Murata Takeo Tanaka Yoshio Nose Chikage Kihara Kosuke Uchida Shinichi Okuda Takehisa Susa Yukari Kishida Masunori Matsuzaki
- 出版者
- The Japanese Circulation Society
- 雑誌
- Circulation Journal (ISSN:13469843)
- 巻号頁・発行日
- vol.76, no.3, pp.675-681, 2012 (Released:2012-02-24)
- 参考文献数
- 24
- 被引用文献数
- 24 28
Background: The time interval between the onset of early transmitral flow velocity (E) and that of early diastolic mitral annular velocity (e') (TE-e') is a good predictor of elevated left ventricular (LV) filling pressure in patients with sinus rhythm. Although the evaluation of LV filling pressure using E/e' has been challenging in atrial fibrillation (AF), the usefulness of TE-e' is unknown. Methods and Results: E and e' were simultaneously recorded using dual Doppler echocardiography in 45 AF patients (30 men; mean age, 69±9 years). E/e' and TE-e' were calculated and compared with the pulmonary capillary wedge pressure (PCWP), which was measured invasively. E/e' and TE/e' correlated with PCWP (E/e', r=0.57, P<0.001; TE-e', r=0.77, P<0.001). Using receiver operating characteristic analysis, the optimal cut-off for TE-e' was 34ms (sensitivity, 95%; specificity, 88%) and that for E/e' was 14.6 (sensitivity, 50%; specificity, 84%) in order to predict >12-mmHg PCWP. When the combined cut-offs of TE-e' >34ms and E/e' >14.6 were used, the sensitivity and specificity of predicting elevated PCWP were improved to 100% and 88%, respectively. Conclusions: In AF patients, the simultaneous recording of E and e' using dual Doppler echocardiography and the analysis of TE-e', in addition to E/e', improved the accuracy of evaluation of LV filling pressure. (Circ J 2012; 76: 675-681)