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Wakabayashi H.,Kanazawa University | Taki J.,Kanazawa University | Inaki A.,Kanazawa University | Shiba K.,Kanazawa University | And 2 more authors.
EJNMMI Research | Year: 2015

Background: To investigate whether an apoptotic process demonstrated by 99mTc-annexin-V (99mTc-AV) uptake correlates with left ventricular remodeling (LVR) after myocardial infarction, we assessed 99mTc-AV uptake in rat model of myocardial ischemia and reperfusion. Methods: The left coronary artery (LCA) of 15 rats was occluded for 20 to 30 min, followed by reperfusion. After 2 weeks, 99mTc-AV was injected, and then 1 h later, 201Tl was injected after reocclusion of the LCA. Dual-tracer autoradiography was performed to assess 99mTc-AV uptake and the area at risk (AAR) by 201Tl defect. 99mTc-AV uptake ratio was calculated by dividing the count density of the AAR by that of the normally perfused area. In short-axis LV slices, LV cavity dilation index (DI) was calculated by dividing the area of LV cavity by that of the whole LV area. LV wall-thinning ratio (WTR) was calculated by dividing the LV wall thickness in the AAR by that of the normally perfused area. Results: Significant 99mTc-AV uptake in the AAR was observed in 10 rats. DI was significantly higher in rats with positive 99mTc-AV uptake than in rats without uptake. WTR was smaller in rats with positive 99mTc-AV uptake than in rats without uptake. Conclusions: The data suggest 99mTc-AV uptake in injured myocardium might correlate with LVR at 2 weeks after myocardial ischemia and reperfusion. © 2015, Wakabayashi et al. Source


Taki J.,Kanazawa University | Inaki A.,Kanazawa University | Wakabayashi H.,Kanazawa University | Matsunari I.,The Medical and Pharmacological Research Center Foundation | And 6 more authors.
EJNMMI Research | Year: 2015

Background: Tenascin-C (TNC), an extracellular matrix glycoprotein, is expressed transiently in distinct areas in association with active tissue remodeling. This study aimed to explore how ischemic postconditioning (PC) affects myocardial expression of TNC and ventricular remodeling using 125I-labeled anti-TNC antibody (125I-TNC-Ab) in a rat model of ischemia and reperfusion. Methods: In control rats (n = 27), the left coronary artery (LCA) was occluded for 30 min followed by reperfusion for 1, 3, 7, and 14 days. PC (n = 27) was performed just after the reperfusion. At the time of the study, 125I-TNC-Ab (1.0 to 2.5 MBq) was injected. Six to 9 h later, to verify the area at risk, 99mTc-MIBI (100 to 200 MBq) was injected intravenously just after the LCA reocclusion, with the rats sacrificed 1 min later. Dual tracer autoradiography was performed to assess 125I-TNC-Ab uptake and area at risk. To examine the ventricular remodeling, echocardiography was performed 2 M after reperfusion in both groups. Results: In control rats, 125I-TNC-Ab uptake ratio at 1 day after reperfusion was 3.73 ± 0.71 and increased at 3 days (4.65 ± 0.87), followed by a significant reduction at 7 days (2.91 ± 0.55, P < 0.005 vs 3 days) and14 days (2.01 ± 0.17, P < 0.005 vs 1 and 3 days). PC attenuated the 125I-TNC-Ab uptake throughout the reperfusion time from 1 to 14 days; 2.59 ± 0.59 at 1 day, P < 0.05: 3.10 ± 0.42 at 3 days, P < 0.005: 1.93 ± 0.37 at 7 days, P < 0.05: 1.40 ± 0.07 at 14 days, P < 0.001. In echocardiography, PC reduced the ventricular end-diastolic and systolic dimensions (1.00 ± 0.06 cm to 0.83 ± 0.14 cm (P < 0.05) and 0.90 ± 0.15 cm to 0.62 ± 0.19 cm (P < 0.05), respectively) and prevented a decline of ventricular percentage fractional shortening (10.5 ± 3.7 to 28.2 ± 10.7, P < 0.005). Conclusions: These data indicate that 125I-TNC-Ab imaging may be a way to monitor myocardial injury, the subsequent repair process, and its response to novel therapeutic interventions like PC by visualizing TNC expression. © 2015, Taki et al.; licensee Springer. Source


Fujita W.,Kanazawa Medical University | Matsunari I.,The Medical and Pharmacological Research Center Foundation | Matsunari I.,Saitama University | Aoki H.,Kanazawa Medical University | And 2 more authors.
Annals of Nuclear Medicine | Year: 2016

Objectives: The aim of this study was to determine whether 11C-hydroxyephedrine (11C-HED) can predict adverse events including all-cause death in Japanese patients with left ventricular (LV) dysfunction. Background: Although 11C-HED PET has been used to assess cardiac sympathetic innervation in various disease conditions, data on their prognostic value are limited. Methods: Sixty patients (mean LVEF, 42 ± 14 %) with LV dysfunction (42 ischemic and 18 non-ischemic heart disease) underwent 11C-HED PET. Myocardial retention was calculated for 11C-HED PET as a measure of cardiac sympathetic neuronal integrity. Statistical analysis was performed using Cox proportional hazards regression and log-rank test. Results: Thirteen deaths (7 cardiac and 6 non-cardiac deaths) occurred during a mean follow-up period of 33 ± 23 months. The patients with death were associated with significantly lower 11C-HED retention (7.1 ± 2.1 vs 9.0 ± 2.4, p = 0.015) than those without death. The hazard ratio for global 11C-HED retention per unit (/min) was 0.762 (p = 0.039), which remained significant in multivariate analysis. When the patients were divided into the high (≥8.5) and low (<8.5) 11C-HED retention groups, the low 11C-HED retention group was associated with significantly poorer survival than the high 11C-HED retention group (p = 0.004). Conclusion: The low global 11C-HED retention is a marker of poor overall survival in patients with LV dysfunction in this study. © 2016 The Author(s) Source


Shima K.,Kanazawa University | Matsunari I.,The Medical and Pharmacological Research Center Foundation | Samuraki M.,Kanazawa University | Chen W.-P.,The Medical and Pharmacological Research Center Foundation | And 8 more authors.
Neurobiology of Aging | Year: 2012

To test the hypothesis that Alzheimer's disease (AD) patients with posterior cingulate/precuneus (PCP) atrophy would be a distinct disease form in view of metabolic decline. Eighty-one AD patients underwent 18F-fluorodeoxyglucose (FDG) positron emission tomography (PET) and structural magnetic resonance imaging (MRI). Positron emission tomography and voxel-based morphometry (VBM) Z-score maps were generated for the individual patients using age-specific normal databases. The patients were classified into 3 groups based on atrophic patterns (no-Hipp-PCP, atrophy in neither hippocampus nor PCP; Hipp, hippocampal atrophy; PCP, PCP atrophy). There were 16 patients classified as no-Hipp-PCP, 55 as Hipp, and 10 as PCP. The Mini Mental State Examination (MMSE) score was similar among the groups. The greater FDG decline than atrophy was observed in all groups, including the no-Hipp-PCP. The PCP group was younger, and was associated with a greater degree of FDG decline in PCP than the others. There are diverse atrophic patterns in a spectrum of AD. In particular, a subset of patients show PCP atrophy, which is associated with greater metabolic burden. © 2012 Elsevier Inc. Source


Samuraki M.,Kanazawa University | Matsunari I.,The Medical and Pharmacological Research Center Foundation | Chen W.-P.,The Medical and Pharmacological Research Center Foundation | Shima K.,Kanazawa University | And 4 more authors.
Neurobiology of Aging | Year: 2012

Apolipoprotein E (ApoE) ε4 is known as a genetic risk factor for Alzheimer's disease (AD). This study investigated the prevalence of imaging abnormalities suggestive of AD in cognitively normal ApoE ε4 carriers using 18F-fluorodeoxyglucose (FDG) positron emission tomography (PET) and voxel-based morphometry (VBM). Forty-five cognitive normal ApoE ε4 allele carriers and 45 noncarriers underwent both FDG positron emission tomography and magnetic resonance imaging (MRI). A total of 90 normal database sets were generated for the individual 45 ε4 carriers and 45 noncarriers. Mean z-scores in the predefined AD-specific regions of interest (ROI) were calculated for each ε4 carrier and noncarrier using the individually defined normal database. The prevalence of AD-like hypometabolism and atrophy in the ε4 carriers was 8.9% and 17.7%, respectively, and did not differ significantly from those in the noncarriers (8.9%, 8.8%). The majority of ε4 carriers showed preserved FDG uptake or gray matter concentration. © 2012 Elsevier Inc. Source

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