Search

Your search keyword '"Atsushi Ishizaki"' showing total 2 results
Start Over Author "Atsushi Ishizaki" Journal plos one
2 results on '"Atsushi Ishizaki"'

1. Development of novel radiogallium-labeled bone imaging agents using oligo-aspartic acid peptides as carriers.

Author

Kazuma Ogawa, Atsushi Ishizaki, Kenichiro Takai, Yoji Kitamura, Tatsuto Kiwada, Kazuhiro Shiba, and Akira Odani

Subjects
Medicine, Science
Abstract

(68)Ga (T 1/2 = 68 min, a generator-produced nuclide) has great potential as a radionuclide for clinical positron emission tomography (PET). Because poly-glutamic and poly-aspartic acids have high affinity for hydroxyapatite, to develop new bone targeting (68)Ga-labeled bone imaging agents for PET, we used 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (DOTA) as a chelating site and conjugated aspartic acid peptides of varying lengths. Subsequently, we compared Ga complexes, Ga-DOTA-(Asp)n (n = 2, 5, 8, 11, or 14) with easy-to-handle (67)Ga, with the previously described (67)Ga-DOTA complex conjugated bisphosphonate, (67)Ga-DOTA-Bn-SCN-HBP. After synthesizing DOTA-(Asp)n by a Fmoc-based solid-phase method, complexes were formed with (67)Ga, resulting in (67)Ga-DOTA-(Asp)n with a radiochemical purity of over 95% after HPLC purification. In hydroxyapatite binding assays, the binding rate of (67)Ga-DOTA-(Asp)n increased with the increase in the length of the conjugated aspartate peptide. Moreover, in biodistribution experiments, (67)Ga-DOTA-(Asp)8, (67)Ga-DOTA-(Asp)11, and (67)Ga-DOTA-(Asp)14 showed high accumulation in bone (10.5 ± 1.5, 15.1 ± 2.6, and 12.8 ± 1.7% ID/g, respectively) but were barely observed in other tissues at 60 min after injection. Although bone accumulation of (67)Ga-DOTA-(Asp)n was lower than that of (67)Ga-DOTA-Bn-SCN-HBP, blood clearance of (67)Ga-DOTA-(Asp)n was more rapid. Accordingly, the bone/blood ratios of (67)Ga-DOTA-(Asp)11 and (67)Ga-DOTA-(Asp)14 were comparable with those of (67)Ga-DOTA-Bn-SCN-HBP. In conclusion, these data provide useful insights into the drug design of (68)Ga-PET tracers for the diagnosis of bone disorders, such as bone metastases.

Published
2013
Full Text
View/download PDF

2. Development of novel radiogallium-labeled bone imaging agents using oligo-aspartic acid peptides as carriers

Author

Atsushi Ishizaki, Kazuhiro Shiba, Akira Odani, Kazuma Ogawa, Yoji Kitamura, Kenichiro Takai, and Tatsuto Kiwada

Subjects
Anatomy and Physiology, Radionuclide imaging, PET imaging, Hydroxyapatite binding, lcsh:Medicine, Peptide, Biochemistry, High-performance liquid chromatography, Metastasis, Synthesis, chemistry.chemical_compound, Basic Cancer Research, Aspartic acid, Tissue Distribution, lcsh:Science, Musculoskeletal System, Chromatography, High Pressure Liquid, Drug Distribution, chemistry.chemical_classification, Multidisciplinary, Molecular Structure, Chemistry, Chemical Reactions, Oncology, Medicine, Radiology, Research Article, Drugs and Devices, Biodistribution, Gallium Radioisotopes, Conjugated system, Bone and Bones, Heterocyclic Compounds, 1-Ring, Humans, DOTA, Pharmacokinetics, Chelation, Bone, Biology, neoplasms, Solid-Phase Synthesis Techniques, Radiochemistry, lcsh:R, Radiobiology, Durapatite, Metabolism, Positron-Emission Tomography, Nuclear medicine, lcsh:Q, Medicinal Chemistry, Radiopharmaceuticals, Peptides
Abstract

金沢大学疾患モデル総合研究センター, 68Ga (T1/2 = 68 min, a generator-produced nuclide) has great potential as a radionuclide for clinical positron emission tomography (PET). Because poly-glutamic and poly-aspartic acids have high affinity for hydroxyapatite, to develop new bone targeting 68Ga-labeled bone imaging agents for PET, we used 1,4,7,10-tetraazacyclododecane-1,4,7,10- tetraacetic acid (DOTA) as a chelating site and conjugated aspartic acid peptides of varying lengths. Subsequently, we compared Ga complexes, Ga-DOTA-(Asp)n (n = 2, 5, 8, 11, or 14) with easy-to-handle 67Ga, with the previously described 67Ga-DOTA complex conjugated bisphosphonate, 67Ga-DOTA-Bn-SCN-HBP. After synthesizing DOTA-(Asp)n by a Fmoc-based solid-phase method, complexes were formed with 67Ga, resulting in 67Ga-DOTA-(Asp)n with a radiochemical purity of over 95% after HPLC purification. In hydroxyapatite binding assays, the binding rate of 67Ga-DOTA-(Asp)n increased with the increase in the length of the conjugated aspartate peptide. Moreover, in biodistribution experiments, 67Ga-DOTA-(Asp) 8, 67Ga-DOTA-(Asp)11, and 67Ga-DOTA- (Asp)14 showed high accumulation in bone (10.5±1.5, 15.1±2.6, and 12.8±1.7% ID/g, respectively) but were barely observed in other tissues at 60 min after injection. Although bone accumulation of 67Ga-DOTA-(Asp)n was lower than that of 67Ga-DOTA-Bn-SCN-HBP, blood clearance of 67Ga-DOTA-(Asp)n was more rapid. Accordingly, the bone/blood ratios of 67Ga-DOTA-(Asp) 11 and 67Ga-DOTA-(Asp)14 were comparable with those of 67Ga-DOTA-Bn-SCN-HBP. In conclusion, these data provide useful insights into the drug design of 68Ga-PET tracers for the diagnosis of bone disorders, such as bone metastases. © 2013 Ogawa et al., CC-BY 4.0

Published
2013

Catalog

Books, media, physical & digital resources
See catalog results