title: Comparison of cationic myocardial perfusion agents: characteristics of accumulation in cultured smooth muscle cells.
abstract: The uptake and washout kinetics of two cationic lipophilic 99mTc-labeled myocardial perfusion agents, 99mTc-methoxyisobutylisonitrile (99mTc-MIBI) 99mTc-1,2-bis[bis-2-ethoxyethyl)-phosphino]ethane (99mTc-Tetrofosmin), were studied in cultured smooth muscle cells and compared to the conventional myocardial perfusion agent, 201Tl. Both 99mTc-MIBI and 99mTc-Tetrofosmin had a 4-fold greater uptake then 201Tl, and they were washed out of cells through similar kinetics which had slower rates than 201Tl. Incubation with metabolism inhibitors had a modest influence on the uptake of these two 99mTc-labeled agents, although their extent and inhibited sites were slightly different. Ion transport inhibitors did not affect the uptake of 99mTc-MIBI, although the 99mTc-Tetrofosmin uptake was slightly inhibited when the Ca2+ channel was blocked. Our studies indicate that 99mTc-MIBI and 99mTc-Tetrofosmin were taken up by smooth muscle cells in similar pharmacokinetic patterns, but their accumulation reflected a different meaning for cell viability.
authors.affiliation: Department of Radiology, Keio University School of Medicine, Tokyo, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Nakamura
authors.forename: T
authors.initials: T
authors.lastname: Sammiya
authors.forename: J
authors.initials: J
authors.lastname: Hashimoto
authors.forename: R
authors.initials: R
authors.lastname: Ishibashi
authors.forename: K
authors.initials: K
authors.lastname: Matsumoto
authors.forename: A
authors.initials: A
authors.lastname: Kubo
mesh_terms: D000963:Antimetabolites / Q000494:pharmacology; D001693:Biological Transport, Active / Q000187:drug effects; D002478:Cells, Cultured; D006321:Heart / Q000000981:diagnostic imaging* / Q000187:drug effects; D006801:Humans; D009131:Muscle, Smooth, Vascular / Q000000981:diagnostic imaging* / Q000187:drug effects / Q000378:metabolism; D009206:Myocardium / Q000378:metabolism; D009943:Organophosphorus Compounds / Q000493:pharmacokinetics; D015609:Organotechnetium Compounds / Q000493:pharmacokinetics; D011877:Radionuclide Imaging; D019275:Radiopharmaceuticals / Q000493:pharmacokinetics; D017256:Technetium Tc 99m Sestamibi / Q000493:pharmacokinetics; D013794:Thallium Radioisotopes / Q000493:pharmacokinetics
chemical_list: D000963:Antimetabolites; D009943:Organophosphorus Compounds; D015609:Organotechnetium Compounds; D019275:Radiopharmaceuticals; D013794:Thallium Radioisotopes; C078700:technetium tc-99m tetrofosmin; D017256:Technetium Tc 99m Sestamibi