title: Comparison of myocardial cell survival 2 h and 24 h after extracellular talaporfin sodium-induced photodynamic reaction.
abstract: BACKGROUND
  We have proposed an application of photodynamic reaction for less-heated myocardial ablation which employs talaporfin sodium. Intracellular photodynamic reactions with ongoing uptake have the ability to induce apoptosis over time, raising the possibility of extending the lesion depth. The objective of this study was to understand how, in myocardial cells, the late cell survival levels change by incubation time with talaporfin sodium, and what dependence talaporfin sodium uptake has on the duration of incubation with talaporfin sodium in vitro.
  
  
  METHODS
  Rat myocardial cells were incubated with talaporfin sodium for 5-360 min and intracellular concentrations measured using a fluorescence micro-plate reader after wash. Cell survival was measured using a water-soluble tetrazolium assay at 2 and 24 h after a photodynamic reaction using a red diode laser of 660 nm, following 15-180 min of incubation with talaporfin sodium. Cells were stained with Hoechst 33342 to observe nuclear changes.
  
  
  RESULTS
  Intracellular talaporfin sodium concentration increased with incubation time, with a marked increase between 0 and 60 min. Cell survival at 24 h decreased by 20% when the duration of incubation with talaporfin sodium was extended from 15 to 30 min. Following incubation time of 30-180 min with talaporfin sodium, cell survival was decreased by approximately 30% between measurements at 2 and 24 h. The intracellular talaporfin sodium concentration that induced higher levels of late cell death with cell nuclei fragmentation in these cells was approximately 0.2 μg/mL.
  
  
  CONCLUSIONS
  We obtained the characteristics of late cell death occurrence and talaporfin sodium uptake to myocardial cell with various incubation times with talaporfin sodium.
authors.affiliation: School of Fundamental Science and Technology, Graduate School of Science and Technology, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama 223-8522, Japan. Electronic address: e.ogawa@arai.appi.keio.ac.jp.
authors.forename: Emiyu
authors.initials: E
authors.lastname: Ogawa
authors.affiliation: School of Fundamental Science and Technology, Graduate School of Science and Technology, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama 223-8522, Japan. Electronic address: n.machida@arai.appi.keio.ac.jp.
authors.forename: Naoki
authors.initials: N
authors.lastname: Machida
authors.affiliation: School of Fundamental Science and Technology, Graduate School of Science and Technology, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama 223-8522, Japan. Electronic address: a.ito@arai.appi.keio.ac.jp.
authors.forename: Arisa
authors.initials: A
authors.lastname: Ito
authors.affiliation: School of Fundamental Science and Technology, Graduate School of Science and Technology, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama 223-8522, Japan. Electronic address: tsunearai@appi.keio.ac.jp.
authors.forename: Tsunenori
authors.initials: T
authors.lastname: Arai
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000187:drug effects* / Q000528:radiation effects; D002470:Cell Survival / Q000187:drug effects* / Q000528:radiation effects; D002478:Cells, Cultured; D004305:Dose-Response Relationship, Drug; D004307:Dose-Response Relationship, Radiation; D008027:Light; D032342:Muscle Cells / Q000187:drug effects* / Q000528:radiation effects*; D010778:Photochemotherapy / Q000379:methods*; D017319:Photosensitizing Agents / Q000008:administration & dosage; D011166:Porphyrins / Q000008:administration & dosage*; D011829:Radiation Dosage; D051381:Rats
chemical_list: D017319:Photosensitizing Agents; D011166:Porphyrins; C053434:Talaporfin
keywords: Extracellular photodynamic reaction; Myocardial cell; Photocytotoxicity; Talaporfin sodium