VALIDATING THE THEORY OF PHASE TRANSITION FROM CALCIUM OXALATE DIHYDRATE TO MONOHYDRATE IN THE STONE FORMATION: THE FIRST ARTIFICIAL IN VIVO EXPERIMENT

You have accessJournal of UrologyCME1 Apr 2023MP05-07 VALIDATING THE THEORY OF PHASE TRANSITION FROM CALCIUM OXALATE DIHYDRATE TO MONOHYDRATE IN THE STONE FORMATION: THE FIRST ARTIFICIAL IN VIVO EXPERIMENT Mihoko Maruyama, Uta Michibata, Yutaro Tanaka, Hiroshi Yoshikawa, Kazufumi Takano, Rie Tajiri, Kazumi Taguchi, Shuzo Hamamoto, Atsushi Okada, Takahiro Yasui, Shigeyoshi Usami, Masayuki Imanishi, Masashi Yoshimura, and Yusuke Mori Mihoko MaruyamaMihoko Maruyama More articles by this author , Uta MichibataUta Michibata More articles by this author , Yutaro TanakaYutaro Tanaka More articles by this author , Hiroshi YoshikawaHiroshi Yoshikawa More articles by this author , Kazufumi TakanoKazufumi Takano More articles by this author , Rie TajiriRie Tajiri More articles by this author , Kazumi TaguchiKazumi Taguchi More articles by this author , Shuzo HamamotoShuzo Hamamoto More articles by this author , Atsushi OkadaAtsushi Okada More articles by this author , Takahiro YasuiTakahiro Yasui More articles by this author , Shigeyoshi UsamiShigeyoshi Usami More articles by this author , Masayuki ImanishiMasayuki Imanishi More articles by this author , Masashi YoshimuraMasashi Yoshimura More articles by this author , and Yusuke MoriYusuke Mori More articles by this author View All Author Informationhttps://doi.org/10.1097/JU.0000000000003216.07AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookLinked InTwitterEmail Abstract INTRODUCTION AND OBJECTIVE: We have previously reported that the phase transition phenomenon of calcium oxalate (CaOx) makes urinary stones harder. Knowing phase transition velocity helps estimate the change of the patient's stone hardness over time. It affects the decision-making of the fragmentation treatment methods. However, the mechanism of the phase transition has not been clarified. Therefore, we stimulated the phase transition of CaOx dihydrate (COD) stone to CaOx monohydrate (COM), and observed the time course of the internal and surface structure. METHODS: A urinary stone mainly composed of COD, in which the phase transition has not progressed much, was stored in a vial containing CaOx supersaturated solution at 37oC with gentle shaking. We picked up the stone from the solution every week and observed the phase transition process from COD to COM. X-ray micro-CT and scanning electron microscopy were introduced. After completing the phase transition observation, a thin section of the stone was prepared. Then, the phase identification was performed in more detail using polarizing microscopy and Raman microscopy. RESULTS: The dissolution of the COD crystal surface and nucleation of COM crystals co-occurred. The inside of the COD stone underwent a phase transition to COM. After the transition, we found typical mosaic and concentric structures of COM (Figure 1). The extent of the transition from COD to COM strongly depended on the area. An area where crystal defects, cracks, and crystal boundaries exist, transited fast (∼10 μm/h); a few millimeter size COD crystals almost turned into COM structures in only two weeks. The transition ratio was faster than that in the human body. CONCLUSIONS: We have succeeded in the world's first artificial urinary stone phase transition experiment. Once the phase transition starts, rapid progress possibly occurs. Further, transformation velocity strongly depends on COD crystal structure and aggregation state. Our observation showed experimental phase transition of a natural urinary stone is faster than that in the human body, and indicated a potential mechanism enabled to slow down the phase transition of crystals in vivo, which could be useful to prevent stone formation. Source of Funding: JSPS KAKENHI Grant Numbers (JP19K22965, JP20K21658, JP22H00302, JP22H01971) © 2023 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 209Issue Supplement 4April 2023Page: e46 Advertisement Copyright & Permissions© 2023 by American Urological Association Education and Research, Inc.MetricsAuthor Information Mihoko Maruyama More articles by this author Uta Michibata More articles by this author Yutaro Tanaka More articles by this author Hiroshi Yoshikawa More articles by this author Kazufumi Takano More articles by this author Rie Tajiri More articles by this author Kazumi Taguchi More articles by this author Shuzo Hamamoto More articles by this author Atsushi Okada More articles by this author Takahiro Yasui More articles by this author Shigeyoshi Usami More articles by this author Masayuki Imanishi More articles by this author Masashi Yoshimura More articles by this author Yusuke Mori More articles by this author Expand All Advertisement PDF downloadLoading ...