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Dive into the research topics where Yujiro Nakahara is active.

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Featured researches published by Yujiro Nakahara.


Oncotarget | 2016

Somatic mutations in plasma cell-free DNA are diagnostic markers for esophageal squamous cell carcinoma recurrence

Masami Ueda; Tomohiro Iguchi; Takaaki Masuda; Yujiro Nakahara; Hidenari Hirata; Ryutaro Uchi; Atsushi Niida; Kota Momose; Shotaro Sakimura; Kenichi Chiba; Hidetoshi Eguchi; Shuhei Ito; Keishi Sugimachi; Makoto Yamasaki; Yutaka Suzuki; Satoru Miyano; Yuichiro Doki; Masaki Mori; Koshi Mimori

Objectives Esophageal squamous cell carcinoma (ESCC) is one of the most aggressive malignancies owing to the high frequency of tumor recurrence. The identification of markers for early ESCC diagnosis and prediction of recurrence is expected to improve the long-term prognosis. Therefore, we searched for associations between tumor recurrence and cell-free DNA (cfDNA) mutations in blood plasma, which contains genetic markers for various cancer types. Experimental Design Genomic DNA from tumors and cfDNA from plasma were obtained from 13 patients undergoing treatment for newly diagnosed ESCC. Next-generation sequencing of cfDNA in plasma was performed to identify mutations in 53 cancer-related genes, in which recurrent mutations were previously detected in ESCC. cfDNA mutational profiles were compared before and after tumor resection in four patients. Furthermore, somatic mutations in serial plasma samples were monitored after treatment in four patients. Results We identified multiple concordant somatic mutations in cfDNA and primary tumor samples from 10 patients (83.3%) and in cfDNA and metastatic tumor samples from one patient (100%). Furthermore, the allele frequency of the concordant mutations in cfDNA changed concomitantly with tumor burden and increased approximately 6 months earlier than the detection of tumor recurrences by imaging tests in two patients. Conventional biomarkers, such as SCC and p53-Ab, did not reflect tumor recurrences. Conclusions The present multigene panel, which enabled the diagnosis of tumor recurrence with greater accuracy than did using standard tumor markers or imaging methods, is expected to greatly facilitate standard, postoperative follow-up monitoring in ESCC.


Minimally Invasive Therapy & Allied Technologies | 2014

A novel locally operated master-slave robot system for single-incision laparoscopic surgery

Yuki Horise; Toshinobu Matsumoto; Hiroki Ikeda; Yuta Nakamura; Makoto Yamasaki; Genta Sawada; Yukiko Tsukao; Yujiro Nakahara; Masaaki Yamamoto; Shuji Takiguchi; Yuichiro Doki; Masaki Mori; Fumio Miyazaki; Mitsugu Sekimoto; Toshikazu Kawai; Atsushi Nishikawa

Abstract Purpose: Single-incision laparoscopic surgery (SILS) provides more cosmetic benefits than conventional laparoscopic surgery but presents operational difficulties. To overcome this technical problem, we have developed a locally operated master-slave robot system that provides operability and a visual field similar to conventional laparoscopic surgery. Material and methods: A surgeon grasps the master device with the left hand, which is placed above the abdominal wall, and holds a normal instrument with the right hand. A laparoscope, a slave robot, and the right-sided instrument are inserted through one incision. The slave robot is bent in the body cavity and its length, pose, and tip angle are changed by manipulating the master device; thus the surgeon has almost the same operability as with normal laparoscopic surgery. To evaluate our proposed system, we conducted a basic task and an ex vivo experiment. Results: In basic task experiments, the average object-passing task time was 9.50 sec (SILS cross), 22.25 sec (SILS parallel), and 7.23 sec (proposed SILS). The average number of instrument collisions was 3.67 (SILS cross), 14 (SILS parallel), and 0.33 (proposed SILS). In the ex vivo experiment, we confirmed the applicability of our system for single-port laparoscopic cholecystectomy. Conclusion: We demonstrated that our proposed robot system is useful for single-incision laparoscopic surgery.


Oncology | 2016

Downregulation of SIRT4 Expression Is Associated with Poor Prognosis in Esophageal Squamous Cell Carcinoma

Yujiro Nakahara; Makoto Yamasaki; Genta Sawada; Yasuhiro Miyazaki; Tomoki Makino; Tsuyoshi Takahashi; Yukinori Kurokawa; Kiyokazu Nakajima; Shuji Takiguchi; Koshi Mimori; Masaki Mori; Yuichiro Doki

Objective: SIRT4, a mitochondria-localized sirtuin, represses glutamine metabolism by inhibiting glutamate dehydrogenase (GDH). The current study aimed to evaluate the clinical and biological significance of SIRT4 in esophageal squamous cell carcinoma (ESCC). Methods: The study comprised 172 patients with surgically resected ESCC in two independent cohorts. SIRT4 mRNA expression was analyzed in Cohort 1 (n = 79) and SIRT4 protein expression in Cohort 2 (n = 93). The association of SIRT4 expression with clinicopathological parameters and prognosis was assessed. Furthermore, the biological role of SIRT4 in ESCC cell lines was examined. Results: SIRT4 expression was not correlated with any clinicopathological parameters in both cohorts. In Cohort 1, low-SIRT4-expression cases had poorer overall survival than high-SIRT4-expression cases (p = 0.016). In Cohort 2, SIRT4-negative cases had poorer overall survival and disease-free survival than SIRT4-positive cases (p = 0.011 and 0.0026). Multivariate analysis revealed that SIRT4 expression was an independent prognostic factor for overall survival (HR = 2.06, p = 0.038). The rate of distant recurrence was significantly higher in SIRT4-negative cases than in SIRT4-positive cases (39.4 vs. 7.4%; p = 0.0023). In vitro, SIRT4 knockdown significantly increased GDH activity and promoted cell proliferation and migration. Conclusion: SIRT4 is a potential prognostic biomarker in ESCC.


International Journal of Surgery Case Reports | 2018

Primary splenic malignant lymphoma mimicking metastasis of rectosigmoid cancer: A case report

Masaki Wakasugi; Yumiko Yasuhara; Yujiro Nakahara; Takashi Matsumoto; Hiroyoshi Takemoto; Ko Takachi; Kiyonori Nishioka; Kyotaro Yoshida; Satoshi Oshima

Highlights • Primary splenic malignant lymphoma should be included among the differential diagnoses of splenic tumors.• Curative resection might be a therapeutic option for the treatment of primary splenic malignant lymphoma.• Laparoscopy-assisted splenectomy is useful for reducing the length of incisions and the operative invasiveness.


International Journal of Surgery Case Reports | 2018

Intraabdominal actinomycosis resulting in a difficult to diagnose intraperitoneal mass: A case report

Naoto Tsujimura; Hiroyoshi Takemoto; Yujiro Nakahara; Masaki Wakasugi; Takashi Matsumoto; Kiyonori Nishioka; Kou Takachi; Satoshi Oshima; Kyotaro Yoshida

Highlights • Actinomycosis is a chronic suppurative granulomatous disease caused by Actinomyces israelii.• Actinomycosis is one of the differential diagnoses of an abdominal mass.• The first choice of treatment for actinomycosis is surgical resection.


Asian Journal of Endoscopic Surgery | 2018

Efficacy of single-incision laparoscopic totally extraperitoneal repair for irreducible or incarcerated inguinal hernia: SILS-TEP for incarcerated inguinal hernia

Masaki Wakasugi; Yujiro Nakahara; Masaki Hirota; Takashi Matsumoto; Hiroyoshi Takemoto; Ko Takachi; Kiyonori Nishioka; Satoshi Oshima

The aim of this study was to evaluate the efficacy of single‐incision laparoscopic surgery for totally extraperitoneal repair (SILS‐TEP) of irreducible inguinal hernias and incarcerated inguinal hernias.


Annals of medicine and surgery | 2018

Single-incision laparoscopic preperitoneal mesh repair of supra-pubic incisional hernia: A case report

Masaki Wakasugi; Yujiro Nakahara; Masaki Hirota; Takashi Matsumoto; Takashi Kusu; Hiroyoshi Takemoto; Ko Takachi; Satoshi Oshima

Introduction Repair of supra-pubic incisional hernia is still challenging because of the highest pressure at the lower abdominal wall in the erect position. Recently, laparoscopic preperitoneal mesh repair has been gradually reported. Case presentation A 77-year-old woman underwent single-incision laparoscopic preperitoneal mesh repair under a diagnosis of a supra-pubic incisional hernia, measuring 7 × 4 cm. A single, 2.5-cm, intraumbilical incision was made, followed by creation of the preperitoneal space. Then, the posterior rectus sheath and peritoneum were opened, and laparoscopic exploration was performed. After dissection of the supra-pubic hernia content, the tube for degassing the abdominal cavity was inserted into the abdominal cavity, and the peritoneum and the posterior sheath were closed. The preperitoneal space was dissected gradually, and circular dissection of the hernia sac was performed. The proximal sac (peritoneum) was sutured continuously. A 15 × 10 cm mesh was placed in the preperitoneal space and fixed securely with absorbable tacks at the pubic bone, Coopers ligament, and the rectus abdominis muscle, respectively. After degassing the preperitoneal space, a second laparoscopic exploration was performed to confirm the secure suture of the peritoneum and no injury of the abdominal organs. At 4-month follow-up, the patient remained well with no signs of recurrence. Discussion Single-incision laparoscopic preperitoneal mesh repair could minimize the recurrence of supra-umbilical incisional hernia and perioperative complications. Conclusion Single-incision laparoscopic preperitoneal mesh repair, offering good cosmetic results, might be useful for repair of supra-pubic incisional hernia.


Oncology | 2016

Contents Vol. 90, 2016

Moses Galukande; Henry Wabinga; Florence Mirembe; Charles Karamagi; Alexzander Asea; Berit Jordan; Franziska Jahn; Carsten Müller-Tidow; Karin Jordan; Juliane Beckmann; Susanne Unverzagt; Kai Wang; Rachel L. Erlich; Doron Lipson; Jeffrey S. Ross; Vincent A. Miller; Siraj M. Ali; Philip J. Stephens; Andreas Heilmann; Vivek Subbiah; James Sun; Julia A. Elvin; Juliann Chmielecki; Steven I. Sherman; Ravi Murthy; Naifa L. Busaidy; Ishwaria M. Subbiah; Roman Yelensky; Chaitali Singh Nangia; Jo-Anne Vergilio

A.B. Benson, Chicago, Ill. A. Chang, Singapore A.L. Cheng, Taipei J.F. Cleary, Madison, Wis. M. Dietel, Berlin M.S. Ernstoff, Cleveland, Ohio M.G. Fakih, Duarte, Calif. J.J. Grau, Barcelona H. Gronemeyer, Illkirch D.F. Hayes, Ann Arbor, Mich. C.S. Johnson, Buffalo, N.Y. M.J. Kelley, Durham, N.C. L. Kumar, New Delhi P.J. Loehrer, Indianapolis, Ind. J.R. Marshall, Buffalo, N.Y. S. Monfardini, Milan R. Nagler, Haifa R. Ohno, Nagoya B. Pestalozzi, Zurich H.M. Pinedo, Amsterdam E.A. Repasky, Buffalo, N.Y. A. Semczuk, Lublin E.F. Smit, Amsterdam C.N. Sternberg, Rome R. Stupp, Zurich M.S. Tallman, New York, N.Y. S. Tanaka, Hiroshima M. Tian, Houston, Tex. D.L. Trump, Buffalo, N.Y. T. Wiegel, Ulm W. Yasui, Hiroshima H. Zhang, Hangzhou City Editor-in-Chief


Nihon Rinsho Geka Gakkai Zasshi (journal of Japan Surgical Association) | 2018

Single-incision Laparoscopic Totally Extraperitoneal Repair of Giant Inguinal Hernias

Masaki Wakasugi; Yujiro Nakahara; Masaki Hirota; Hiroyoshi Takemoto; Ko Takachi; Satoshi Oshima


Diseases of The Esophagus | 2018

Reflux after esophagectomy with gastric conduit reconstruction in the posterior mediastinum for esophageal cancer: original questionnaire and EORTC QLQ-C30 survey

Yujiro Nakahara; Makoto Yamasaki; Yasuaki Miyazaki; K Tanaka; Tomoki Makino; Tsuyoshi Takahashi; Yukinori Kurokawa; Kiyokazu Nakajima; Shuji Takiguchi; Masahide Mori; Y. Doki

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Masaki Mori

Ritsumeikan University

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