Point mutations in the mitochondrial (mt) tRNA Leu(UUR) gene are responsible for mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke-like episodes (MELAS), a subgroup of mitochondrial encephalomyopathic diseases. We previously showed that mt tRNA Leu(UUR) with an A3243G or T3271C mutation derived from patients with MELAS are deficient in a normal taurinecontaining modification ( m 5 U; 5-taurinomethyluridine) at the anticodon wobble position. To examine decoding disorder of the mutant tRNA due to the wobble modification deficiency independent of the pathogenic point mutation itself, we used a molecular surgery technique to construct an mt tRNA Leu(UUR) molecule lacking the taurine modification but without the pathogenic mutation. This ''operated'' mt tRNA Leu(UUR) without the taurine modification showed severely reduced UUG translation but no decrease in UUA translation. We thus concluded that the UUG codon-specific translational defect of the mutant mt tRNAs Leu(UUR) is the primary cause of MELAS at the molecular level. This result could explain the complex I deficiency observed clinically in MELAS.

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In Japan, the first endoscopic surgery, a laparoscopic cholecystectomy, was performed in 1990. Since then, operative procedures have been standardized, and the safety and efficacy of endoscopic surgery have been evaluated. In accordance with the social acceptance of endoscopic surgery as a less invasive type of surgery, the number of endoscopic procedures performed has increased in all surgical domains. The Japan Society for Endoscopic Surgery (JSES) has played an important role in the development of endoscopic surgery in Japan. Notably, a technical skills certification system for surgeons was established by the JSES to train instructors on how to teach safe endoscopic surgery. Furthermore, the JSES has conducted a national survey every two years to evaluate the status of endoscopic surgery over time. In 2017, 248 743 patients underwent endoscopic surgery in all surgical domains, such as abdominal, thoracic, mammary and thyroid gland, cardiovascular, obstetrics and gynecology, urologic, orthopedic, and plastic surgery. The 14th National Survey of Endoscopic Surgery conducted by the JSES demonstrated the status of laparoscopic surgery in Japan in 2016‐2017.