Tokyo Medical and Dental University 4 articles published in JoVE Biology Integrated Bone Formation Through In Vivo Endochondral Ossification Using Mesenchymal Stem Cells Shintaro Yamazaki1,2, Yujing Lin3, Eriko Marukawa3, Masa-Aki Ikeda1,3 1Department of Molecular Craniofacial Embryology, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, 2Department of Maxillofacial Surgery, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, 3Department of Regenerative and Reconstructive Dental Medicine, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University Bone therapy via endochondral ossification by implanting artificial cartilage tissue produced from mesenchymal stem cells has the potential to circumvent the drawbacks of conventional therapies. Hyaluronic acid hydrogels are effective in scaling up uniformly differentiated cartilage grafts as well as creating integrated bone with vascularization between fused grafts in vivo. Cancer Research High-sensitivity Detection of Micrometastases Generated by GFP Lentivirus-transduced Organoids Cultured from a Patient-derived Colon Tumor Yu Okazawa1,2, Kosuke Mizukoshi1,2, Yu Koyama2,4, Shoki Okubo5, Hiromitsu Komiyama1, Yutaka Kojima1, Michitoshi Goto1, Sonoko Habu3, Okio Hino2, Kazuhiro Sakamoto1, Akira Orimo2 1Department of Coloproctological Surgery, Juntendo University Faculty of Medicine, 2Department of Molecular Pathogenesis, Juntendo University Faculty of Medicine, 3Atopy Research Center, Juntendo University Faculty of Medicine, 4Department of Oral Pathobiological Science and Surgery, Tokyo Dental College, 5Department of Gastroenterology, Juntendo University Faculty of Medicine To allow highly sensitive detection of the disseminating human colorectal cancer (CRC) cells colonizing tissues, we herein show a protocol for efficient transduction of green fluorescent protein (GFP) lentiviral particles into PDX-derived CRC organoid cells prior to their injection into recipient mice, with stereo-fluorescence microscopic observation. Medicine Electrophysiological Assessment of Murine Atria with High-Resolution Optical Mapping Kensuke Ihara*1, Koji Sugiyama*1, Kentaro Takahashi*1, Masahiro Yamazoe1, Tetsuo Sasano2, Tetsushi Furukawa1 1Department of Bio-informational Pharmacology, Medical Research Institute, Tokyo Medical and Dental University, 2Department of Biofunctional Informatics, Tokyo Medical and Dental University This protocol describes the electrophysiological evaluation of murine atria utilizing an optical mapping system with a high temporal and spatial resolution, including dual recordings of the membrane voltage and Ca2+ transient under programmed stimulation through a specialized electrode catheter. Genetics Generation of a Gene-disrupted Streptococcus mutans Strain Without Gene Cloning Takatoshi Murata1, Ayako Okada1, Khairul Matin1,2,3, Nobuhiro Hanada1 1Department of Translational Research, Tsurumi University School of Dental Medicine, 2Endowed Department of International Oral Health Science (affiliated with Department of Translational Research), Tsurumi University School of Dental Medicine, 3Cariology and Operative Dentistry, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University We describe a facile, rapid, and relatively inexpensive method for the generation of gene-disrupted Streptococcus mutans strains; this technique may be adapted for the generation of gene-disrupted strains of various species.