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| 1.
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Effendia, Nurmaya ; Ogawa, Kazuma ; Mishiro, Kenji ; Takarada, Takeshi ; Yamada, Daisuke ; Kitamura, Yoji ; Shiba, Kazuhiro ; Maeda, Takehiko ; Odani, Akira ; 小川, 数馬 ; 三代, 憲司 ; 宝田, 剛志 ; 北村, 陽二 ; 柴, 和弘 ; 小谷, 明
概要:
金沢大学新学術創成研究機構<br />Platelet-derived growth factor receptor β (PDGFRβ) is a transmembrane tyrosine kinase receptor and it
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is upregulated in various malignant tumors. Radiolabeled PDGFRβ inhibitors can be a convenient tool for the imaging of tumors overexpressing PDGFRβ. In this study, [125I]-1-(5-iodo-2-[5-(2-methoxyethoxy)-1H-benzo[d]imidazol-1-yl]quinoline-8-yl)piperidin-4-amine ([125I]IIQP) and [125I]-N-3-iodobenzoyl-1-(2-[5-(2-methoxyethoxy)-1H-benzo[d]imidazol-1-yl]quinolin-8-yl)-piperidin-4-amine ([125I]IB-IQP) were designed and synthesized, and their potential as PDGFRβ imaging agents was evaluated. In cellular uptake experiments, [125I]IIQP and [125I]IB-IQP showed higher uptake by PDGFRβ-positive cells than by PDGFRβ-negative cells, and the uptake in PDGFRβ-positive cells was inhibited by co-culture with PDGFRβ ligands. The biodistribution of both radiotracers in normal mice exhibited hepatobiliary excretion as the main route. In mice inoculated with BxPC3-luc (PDGFRβ-positive), the tumor uptake of radioactivity at 1h after the injection of [125I]IIQP was significantly higher than that after the injection of [125I]IB-IQP. These results indicated that [125I]IIQP can be a suitable PDGFRβ imaging agent. However, further modification of its structure will be required to obtain a more appropriate PDGFRβ-targeted imaging agent with a higher signal/noise ratio. © 2017.<br />Embargo Period 12 months
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| 2.
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Ogawa, Kazuma ; Ishizaki, Atsushi ; Takai, Kenichiro ; Kitamura, Yoji ; Makino, Akira ; Kozaka, Takashi ; Kiyono, Yasushi ; Shiba, Kazuhiro ; Odani, Akira ; 小川, 数馬 ; 北村, 陽二 ; 小阪, 孝史 ; 柴, 和弘 ; 小谷, 明
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金沢大学新学術創成研究機構<br />67Ga-DOTA-(L-Asp)11 and 67Ga-DOTA-(L-Asp)14, which have been developed as bone imaging agents, showed
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a high accumulation in bone and a rapid blood clearance in mice. However, peptides composed of D-amino acids are more stable in vivo than those composed of their L-equivalents. In this study, 67Ga-DOTA-(D-Asp)n (n = 2, 5, 8, 11, or 14) were synthesized using the Fmoc-based solid-phase methodology and evaluated. In hydroxyapatite binding assay, binding of 67Ga-DOTA-(D-Asp)n tended to increase with increasing length of the amino acid chain. 67Ga-DOTA-(D-Asp)11 and 67Ga-DOTA-(D-Asp)14 caused a high accumulation of radioactivity in the bones of the mice. However, the results for 67Ga-DOTA-(D-Asp)n and 67Ga-DOTA-(L-Asp)n were comparable. In urine analyses, the proportion of intact complex after injection of 67Ga-DOTA-(D-Asp)14 was significantly higher than that of 67Ga-DOTA-(L-Asp)14. Although 67Ga-DOTA-(D-Asp)14 was more stable than 67Ga-DOTA-(L-Asp)14, the properties of 67Ga-DOTA-(D-Asp)n and 67Ga-DOTA-(L-Asp)n as bone imaging agents may be comparable. © 2017 The Author(s).
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| 3.
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Ogawa, Kazuma ; Fukuda, Tadahisa ; Han, Jaegab ; Kitamura, Yoji ; Shiba, Kazuhiro ; Odani, Akira
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Background Release of radionuclides, such as 137Cs and 90Sr, into the atmosphere and the ocean presents an important pro
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blem because internal exposure to 137Cs and 90Sr could be very harmful to humans. Chlorella has been reported to be effective in enhancing the excretion of heavy metals; thus, we hypothesized that Chlorella could also enhance the elimination of 137Cs or 90Sr from the body. We evaluated the potential of Chlorella as a decorporation agent in vitro and in vivo, using 85Sr instead of 90Sr. Methods In vitro experiments of adsorption of 137Cs and 85Sr to Chlorella were performed under wide pH conditions. The maximum sorption capacity of Chlorella to strontium was estimated using the Langmuir model. A 85Sr solution was orally administrated to mice pretreated with Chlorella. At 48 h after 85Sr administration, the biodistribution of radioactivity was determined. Results In the in vitro experiments, although 85Sr barely adsorbed to Chlorella at low pH, the 85Sr adsorption ratio to Chlorella increased with increasing pH. The maximum sorption capacity of Chlorella to strontium was 9.06 mg / g. 137Cs barely adsorbed to Chlorella under any pH conditions. In the biodistribution experiments, bone accumulation of radioactivity after 85Sr administration was significantly decreased in the Chlorella pretreatment group compared with the non-treatment control group. Conclusions In conclusion, these results indicated that Chlorella could inhibit the absorption of 90Sr into the blood and enhance the elimination of 90Sr from the body through adsorption in intestine. Further studies are required to elucidate the mechanism and the components of Chlorella needed for adsorption to strontium and could promote the development of more effective decorporation agents. © 2016 Ogawa et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
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| 4.
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Ogawa, Kazuma ; Ishizaki, Atsushi
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Bone-seeking radiopharmaceuticals are frequently used as diagnostic agents in nuclear medicine, because they can detect
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bone disorders before anatomical changes occur. Furthermore, their effectiveness in the palliation of metastatic bone cancer pain has been demonstrated in the clinical setting. With the aim of developing superior bone-seeking radiopharmaceuticals, many compounds have been designed, prepared, and evaluated. Here, several well-designed bone-seeking compounds used for diagnostic and therapeutic use, having the concept of radiometal complexes conjugated to carrier molecules to bone, are reviewed. © 2015 Kazuma Ogawa and Atsushi Ishizaki.
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| 5.
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Ogawa, Kazuma ; Aoki, Miho
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Since apoptosis plays an important role in maintaining homeostasis and is associated with responses to therapy, molecular imaging of apoptotic cells could be useful for early detection of therapeutic effects, particularly in oncology.
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Radiolabeled annexin V compounds are the hallmark in apoptosis imaging in vivo. These compounds are reviewed from the genesis of apoptosis (cell death) imaging agents up to recent years. They have some disadvantages, including slow clearance and immunogenicity, because they are protein-based imaging agents. For this reason, several studies have been conducted in recent years to develop low molecule apoptosis imaging agents. In this review, radiolabeled phosphatidylserine targeted peptides, radiolabeled bis(zinc(II)-dipicolylamine) complex, radiolabeled 5-fluoropentyl-2-methyl-malonic acid (ML-10), caspase-3 activity imaging agents, radiolabeled duramycin, and radiolabeled phosphonium cation are reviewed as promising low-molecular-weight apoptosis imaging agents.
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| 6.
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Ogawa, Kazuma ; Ono, Masahiro ; Tian, Mei ; Ueda, Masashi ; Higuchi, Takahiro
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Ogawa, Kazuma ; Shiba, Kazuhiro ; Akhter, Nasima ; Yoshimoto, Mitsuyoshi ; Washiyama, Kohshin ; Kinuya, Seigo ; Kawai, Keiichi ; Mori, Hirofumi
概要:
金沢大学医薬保健研究域薬学系<br />It has been reported that sigma receptors are highly expressed in a variety of human tumors. In this
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study, we selected (+)-2-[4-(4-iodophenyl)piperidino] cyclohexanol [(+)-pIV] as a sigma receptor ligand and evaluated the potential of radioiodinated (+)-pIV for tumor imaging and therapy. (+)-[125/131I]pIV was prepared by an iododestannylation reaction under no-carrier-added conditions with radiochemical purity over 99% after HPLC purification. Biodistribution experiments were performed by the intravenous injection of (+)-[125I]pIV into mice bearing human prostate tumors (DU-145). Blocking studies were performed by intravenous injection of (+)-[125I]pIV mixed with an excess amount of unlabeled sigma ligand into DU-145 tumor-bearing mice. For therapeutic study, (+)-[131I]pIV was injected at a dose of 7.4 MBq followed by measurement of the tumor size. In biodistribution experiments, (+)-[125I]pIV showed high uptake and long residence in the tumor. High tumor to blood and muscle ratios were achieved because the radioactivity levels of blood and muscle were low. However, the accumulations of radioactivity in non-target tissues, such as liver and kidney, were high. The radioactivity in the non-target tissues slowly decreased over time. Co-injection of (+)-[125I]pIV with an excess amount of unlabeled sigma ligand resulted in a significant decrease in the tumor/blood ratio, indicating sigma receptor-mediated tumor uptake. In therapeutic study, tumor growth in mice treated with (+)-[131I]pIV was significantly inhibited compared to that of an untreated group. These results indicate that radioiodinated (+)-pIV has a high potential for sigma receptor imaging in tumor and radionuclide receptor therapy. (Cancer Sci 2009). © 2009 Japanese Cancer Association.
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| 8.
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Ogawa, Kazuma ; Takai, Kenichiro ; Kanbara, Hiroya ; Kiwada, Tatsuto ; Kitamura, Youji ; Shiba, Kazuhiro ; Odani, Akira
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金沢大学医薬保健研究域薬学系<br />Introduction: 68Ga is a radionuclide of great interest as a positron emitter for positron emission t
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omography (PET). To develop a new bone-imaging agent with radiogallium, 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (DOTA) was chosen as a chelating site and Ga-DOTA complex-conjugated bisphosphonate, which has a high affinity for bone, was prepared and evaluated. Although we are interested in developing 68Ga-labeled bone imaging agents for PET, in these initial studies 67Ga was used because of its longer half-life. Methods: DOTA-conjugated bisphosphonate (DOTA-Bn-SCN-HBP) was synthesized by conjugation of 2-(4-isothiocyanatebenzyl)-1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid to 4-amino-1-hydroxybutylidene-1,1-bisphosphonate (alendronate). 67Ga-DOTA-Bn-SCN-HBP was prepared by coordination with 67Ga, and its in vitro and in vivo evaluations were performed. Results: 67Ga-DOTA-Bn-SCN-HBP was prepared with a radiochemical purity of over 95% without purification. 67Ga-DOTA-Bn-SCN-HBP had great affinity for hydroxyapatite in binding assay. In biodistribution experiments, 67Ga-DOTA-Bn-SCN-HBP accumulated in bone rapidly but was hardly observed in tissues other than bone. Pretreatment of an excess amount of alendronate inhibited the bone accumulation of 67Ga-DOTA-Bn-SCN-HBP. Conclusions: 67Ga-DOTA-Bn-SCN-HBP showed ideal biodistribution characteristics as a bone-imaging agent. These findings should provide useful information on the drug design of bone imaging agents for PET with 68Ga. © 2010 Elsevier Inc. All rights reserved.
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| 9.
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Ogawa, Kazuma ; Kawashima, Hidekazu ; Kinuya, Seigo ; Shiba, Kazuhiro ; Onoguchi, Masahisa ; Kimura, Hiroyuki ; Hashimoto, Kazuyuki ; Odani, Akira ; Saji, Hideo
概要:
Objective: Rhenium is one of the most valuable elements for internal radiotherapy because 186Re and 188Re have favorable
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physical characteristics. However, there are problems when proteins such as antibodies are used as carriers of 186/188Re. Labeling methods that use bifunctional chelating agents such as MAG3 require the conjugation of the 186/188Re complex to protein after radiolabeling with the bifunctional chelating agent. These processes are complicated. Therefore, we planned the preparation by a simple method and evaluation of a stable 186/188Re-labeled antibody. For this purpose, we selected 186/188Re(I) tricarbonyl complex as a chelating site. In this study, A7 (an IgG1 murine monoclonal antibody) was used as a model protein. 186/188Re-labeled A7 was prepared by directly reacting a 186/188Re(I) tricarbonyl precursor, [186/188Re(CO)3(H2O)3]+, with A7. We then compared the biodistribution of 186/188Re-labeled A7 in tumor-bearing mice with 125I-labeled A7. Methods: For labeling A7, [186/188Re(CO)3(H2O)3]+ was prepared according to a published procedure. 186/188Re-labeled A7 (186/188Re-(CO)3-A7) was prepared by reacting [186/188Re(CO)3(H2O)3]+ with A7 at 43°C for 2 h. Biodistribution experiments were performed by the intravenous administration of 186/188Re-(CO)3-A7 solution into tumor-bearing mice. Results: 186Re-(CO)3-A7 and 188Re-(CO)3-A7 were prepared with radiochemical yields of 23 and 28%, respectively. After purification with a PD-10 column, 186/188Re-(CO)3-A7 showed a radiochemical purity of over 95%. In biodistribution experiments, 13.1 and 13.2% of the injected dose/g of 186Re-(CO)3-A7 and 188Re-(CO)3-A7, respectively, accumulated in the tumor at 24-h postinjection, and the tumor-to-blood ratios were over 2.0 at the same time point. Meanwhile, uptake of 125I-A7 in the tumor was almost the same as that of 186/188Re-(CO)3-A7 at 24-h postinjection. Blood clearances of 186/188Re-(CO)3-A7 were faster than those of 125I-A7. Conclusion: 186/188Re-labeled A7 showed high uptakes in the tumor. However, further modification of the labeling method would be necessary to improve radiochemical yields and their biodistribution. © 2009 The Japanese Society of Nuclear Medicine.
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| 10.
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Taki, Junichi ; Wakabayashi, Hiroshi ; Inaki, Anri ; Imanaka-Yoshida, Kyoko ; Hiroe, Michiaki ; Ogawa, Kazuma ; Morooka, Miyako ; Kubota, Kazuo ; Shiba, Kazuhiro ; Yoshida, Toshimichi ; Kinuya, Seigo
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A relationship between L-[methyl-11C]methionine (11C-methionine) uptake and angiogenesis has been suggested in gliomas.
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However, methionine uptake in myocardial ischemia and reperfusion has received little attention. We investigated the serial changes and mechanisms of 14-Cmethionine uptake in a rat model of myocardial ischemia and reperfusion. Methods: The left coronary artery was occluded for 30 min, followed by reperfusion for 1-28 d. At the time of the study, 14-Cmethionine (0.74 MBq) and 201Tl (14.8 MBq) were injected intravenously at 20 and 10 min before sacrifice, respectively. One minute before sacrifice, the left coronary artery was reoccluded, and 99mTc-hexakis-2-methoxyisobutylisonitrile (150-180 MBq) was injected to verify the area at risk. Histologic sections of the heart were immunohistochemically analyzed using anti-CD68, anti-smooth-muscle a-actin (SMA), and antitroponin I and compared with the autoradiography findings. Results: Both 14Cmethionine (uptake ratio, 0.71 ± 0.13) and 201Tl uptake were reduced in the area at risk at 1 d after reperfusion. However, 3 d after reperfusion, an increased 14-Cmethionine uptake (1.79 ± 0.23) was observed corresponding to the area of still-reduced 201Tl uptake, and the 14-Cmethionine uptake gradually declined until 28 d. The increased 14-Cmethionine uptake area at 3 and 7 d corresponded well to the macrophage infiltrations demonstrated by positive CD68 staining. Anti-SMA staining appeared at 7 d, after which CD68 staining was gradually replaced by the SMA staining, suggesting that methionine uptake in the early phase after ischemia and reperfusion might reflect inflammatory activity. Conclusion: 14-Cmethionine accumulated in the infarcted area, and its uptake corresponded closely to macrophage infiltration at 3-7 d after reperfusion. Methionine imaging may be useful for inflammatory imaging early after myocardial infarction. COPYRIGHT © 2013 by the Society of Nuclear Medicine and Molecular Imaging, Inc.
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