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Niimi, S.,Imoto, M.,Kunisue, T.,Watanabe, M.X.,Kim, E.Y.,Nakayama, K.,Yasunaga, G.,Fujise, Y.,Tanabe, S.,Iwata, H. Academic Press 2014 Ecotoxicology and environmental safety Vol.108 No.-
Hepatic concentrations of persistent organochlorines (OCs) were determined in the common minke whale (Balaenoptera acutorostrata) from the North Pacific. To investigate the effects of OCs on the transcriptome in the minke whale, the present study constructed a hepatic oligo array of this species where 985 unique oligonucleotides were spotted and further analyzed the relationship between the OC levels and gene expression profiles of liver tissues. The stepwise multiple linear regression analysis identified 32 genes that correlated with hepatic OC levels. The mRNA expression levels of seven cytochrome P450 (CYP) genes, CYP1A1, 1A2, 2C78, 2E1, 3A72, 4A35, and 4V6 showed no clear correlations with the concentration of each OC, suggesting that the accumulated OCs in the liver did not reach levels that could alter CYP expression. Among the genes screened by the custom oligo array analysis, hepatic mRNA expression levels of 16 genes were further measured using quantitative real-time reverse transcription polymerase chain reaction. The mRNA levels of vitamin D-binding protein (DBP) were negatively correlated with non-ortho coplanar polychlorinated biphenyl (PCB) levels. Androgen receptor-associated coregulator 70 (ARA70) expression levels showed a significant positive correlation with concentrations of non-ortho coplanar PCB169. These correlations suggest that coplanar PCB-reduced DBP expression could suppress vitamin D receptor-mediated signaling cascades in peripheral tissues. Alternatively, the suppression of vitamin D receptor signaling cascade could be enhanced through competition with the androgen receptor signaling pathway for ARA70. In addition, a negative correlation between kynureninase and PCB169 levels was also observed, which suggest an enhanced accumulation of an endogenous aryl hydrocarbon receptor agonist, kynurenine in the minke whale population. Further studies are necessary to translate the changes in the transcriptome to toxicological outcomes including the disruption of the nervous and immune systems.
Takanaga Niimi,Mamoru Nanasato,Mitsuo Sugimoto,Hisatoshi Maeda 대한핵의학회 2019 핵의학 분자영상 Vol.53 No.1
Objective A recently introduced single-photon emission computed tomography (SPECT), based on cadmium-zinc-telluride (CZT) detectors (D-SPECT), supports high energy resolution for cardiac imaging. Importantly, the high energy resolution may allow simultaneous dual-isotope (SDI) imaging (e.g., using Tc-99m and I-123). We quantitatively evaluated Tc-99m/I- 123 SDI imaging by D-SPECT in comparison with conventional T1-201/I-123. Materials and Methods Energy resolution was measured as a percentage of the full width at half maximum(FWHM) for Tc-99m, I-123, and Tl-201. The impact of cross-talk and reconstructed image contrast were quantified by measuring the contrast-to-noise ratio (CNR), and the transmural defect contrast in the left ventricle wall (CTD) induced by a difference in energy, for combinations of Tc-99m/I-123 or Tl-201/I-123, using an RH-2 cardiac phantom. Corresponding measurement was also carried out in Anger SPECT (A-SPECT). Results The energy resolution of the D-SPECTsystem was 5.4%/5.1%for Tc-99m/I-123 and 5.4%/5.3%for Tl-201/I-123, which was approximately two times higher than the A-SPECT. No notable difference was confirmed in the CNRs of the two systems, but T1-201/I-123 showed overall higher value than Tc-99m/I-123. Compared to A-SPECT, CTD of D-SPECT significantly increased with both Tc-99m/I-123 and T1-201/I-123 (p < 0.05). In DSPECT, the combination of Tc-99m/I-123 had a slightly better CTD than T1-201/I-123. In addition, CTD of Tc-99m/I-123 was improved with scatter correction at both nuclides (p < 0.05), but in Tl-201/I-123, no significant improvement was confirmed in I-123 (p > 0.05). Conclusion D-SPECT was considered to be capable of performing high-quality SDI imaging using Tc-99m/I-123.
Quantification of Contraction Synchronicity and Contraction Work in Coronary Artery Disease
Takanaga Niimi,Mamoru Nanasato,Hisatoshi Maeda 대한핵의학회 2017 핵의학 분자영상 Vol.51 No.3
Purpose This study quantified the contraction synchronicity (CS; with 100% representing full synchrony and −100% dyssynchrony) and contraction work (CW, millijoules per centimeter squared; representingmyocardial area) in patients with reduced left ventricular ejection fraction (LVEF) associated with coronary artery disease (CAD). Methods CS, CW and LVEF in 104 subjects (54 CAD patients and 50 control subjects without CAD) were measured using rest electrocardiography-gated single-photon emission computed tomography (ECG SPECT). Contraction amplitude (CA), synchronous contraction index (SCI), and CW were evaluated using the program Quantification of Segmental Function by Solving the Poisson Equation (QSFP) developed in-house. Results The mean CA, SCI and CW of 17 segments in the control subjects were 33.8 ± 4.1% (±SD), 96.6 ± 1.4%, and 6.9 ± 1.0 mJ/cm2, respectively. In the patients with CAD, the respective values were 26.1 ± 7.3%, 82.1 ± 16.8%, and 5.4 ± 1.6 mJ/cm2. In the CAD patients with LVEF <40% (n = 14), the mean CA, SCI,and CW were 17.9 ± 4.0%, 63.0 ± 18.4%, and 3.5 ± 1.1 mJ/cm2, respectively. These values were significantly lower than in the control subjects (p < 0.005). Using receiver operating characteristic analysis, values for the area under the curve showing the performance of CA, CS,CWand LVEF in the diagnosis of CAD were 0.81, 0.86, 0.78, and 0.84, respectively. Conclusion Asynchrony shown using the QSFP is useful for CAD detection.
Takanaga Niimi,Mamoru Nanasato,Mitsuo Sugimoto,Hisatoshi Maeda 대한핵의학회 2017 핵의학 분자영상 Vol.51 No.4
Purpose The differences in performance between the cadmium-zinc-telluride (CZT) camera or collimation systems and conventional Anger single-photon emission computed tomography (A-SPECT) remain insufficient from the viewpoint of the user. We evaluated the performance of the D-SPECT (Spectrum Dynamics, Israel) system to provide more information to the cardiologist or radiological technologist about its use in the clinical field. Materials and Methods This study evaluated the performance of the D-SPECTsystem in terms of energy resolution, detector sensitivity, spatial resolution, modulation transfer function (MTF), and collimator resolution in comparison with that of A-SPECT (Bright-View, Philips, Japan). Energy resolution and detector sensitivity were measured for Tc-99m, I-123, and Tl-201. The SPECT images produced by both systems were evaluated visually using the anthropomorphic torso phantom. Results The energy resolution of D-SPECT with Tc-99m and I-123 was approximately two times higher than that of ASPECT. The detector sensitivity of D-SPECTwas higher than that of A-SPECT (Tc-99m: 4.2 times, I-123: 2.2 times, and Tl- 201: 5.9 times). The mean spatial resolution of D-SPECTwas two times higher than that of A-SPECT. The MTF of DSPECT was superior to that of the A-SPECT system for all frequencies. The collimator resolution of D-SPECTwas lower than that of A-SPECT; however, the D-SPECT images clearly indicated better spatial resolution than the A-SPECT images. Conclusion The energy resolution, detector sensitivity, spatial resolution, and MTF of D-SPECTwere superior to those of ASPECT. Although the collimator resolution was lower than that of A-SPECT, the D-SPECT images were clearly of better quality.
Michiharu Niimi,Shinpei Noda,Hideki Noda 대한전자공학회 2009 ITC-CSCC :International Technical Conference on Ci Vol.2009 No.7
We have proposed a lossless information hiding method for binary images. A half of pixels in noisy blocks on cover images is candidate for embeddable pixels. Among the candidate pixels, we select compressive pixels by bit patterns of its neighborhood, which is called as neighborhood bit pattern, to compress the pixels effectively. Thus, embeddable pixels in our method are compressive pixels in noisy blocks. This paper reports the influence of block size and neighborhood bit pattern on our method.