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Dive into the research topics where Masanori Yoshimitsu is active.

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Featured researches published by Masanori Yoshimitsu.


Surgery Today | 2008

Objective assessment of endoscopic surgical skills by analyzing direction-dependent dexterity using the Hiroshima University Endoscopic Surgical Assessment Device (HUESAD)

Hiroyuki Egi; Masazumi Okajima; Masanori Yoshimitsu; Satoshi Ikeda; Yoshihiro Miyata; Hirokazu Masugami; Tomohiro Kawahara; Yuichi Kurita; Makoto Kaneko; Toshimasa Asahara

PurposeWe evaluated our system of objectively assessing endoscopic surgical skills.MethodsWe developed the Hiroshima University Endoscopic Surgical Assessment Device (HUESAD), which records the movement of the tip of an endoscopic instrument precisely. The orbits of experienced surgeons (expert group) and those of medical students (novice group) were evaluated by measuring the deviation from the ideal course on horizontal and vertical planes. These data were integrated with the time taken to move the tip of an endoscopic instrument between a distal side pole (A) and a proximal side pole (C) (Task 1), and between a left side pole (D) and a right side pole (B) (Task 2).ResultsThe integrated deviation of the expert group was significantly lower than that of the novice group on both the horizontal and vertical planes in Task 1 (P = 0.0004, P = 0.009) and Task 2 (P < 0.0001, P = 0.0002). Thus, the spatial perception of experts was significantly better than that of novices. We also found that the direction of the scope and the movement of the endoscopic instrument were related to difficulties in spatial perception for both experts and novices. HUESAD detected and resolved these differences based on the directions of the scope and movement of the endoscopic instruments.ConclusionsThe HUESAD is a reliable system for assessing a surgeon’s dexterity, based on direction and movement. It helps us to attain a higher degree of accuracy and to create an ideal setting for optimal endoscopic surgery.


Journal of Visual Languages and Computing | 1996

VIOLONE: Video Retrieval by Motion Example

Atsuo Yoshitaka; Yu-ichi Hosoda; Masanori Yoshimitsu; Masahito Hirakawa; Tadao Ichikawa

Abstract Recent progress in hardware and operating system technologies has made it possible to manage multimedia data consisting of text, static images, sound and/or video. Video data is considered to be the most informative of these types of data. It presents a scene consisting of objects and the motion of objects conveying particular meaning of the scene. Thus, the inherent feature of video data lies in the motion of objects. In this paper, we present a system that retrieves video data by means of the motion of objects observed in the video data in the database. The system accepts a query for a video database, which is specified by drawing an example trajectory of an object, and retrieves video data by extracting a moving object observed in the video data. The proposed way of specifying a query condition is superior to other ways of representing a condition, e.g. by text, in the sense that it is suitable for representing the difference of motion.


Cytokine | 2003

Regulation of T helper type-1 immunity in hapten-induced colitis by host pretreatment with granulocyte colony-stimulating factor☆ ☆

Hiroyuki Egi; Keisuke Hayamizu; Masanori Yoshimitsu; Fumio Shimamoto; Koichi Oishi; Ichiro Ohmori; Masazumi Okajima; Toshimasa Asahara

Recombinant human granulocyte colony-stimulating factor (rhG-CSF) is an immunoregulatory drug whose effects include modulation of antigen-presentation. We investigated the potential ameliorative effect of pretreatment with rhG-CSF in a hapten-induced colitis animal model. Sprague-Dawley rats were given rhG-CSF (125 microg/kg subcutaneously twice a day for 5 days) before a colonic instillation of 2,4,6-trinitrobenzene sulfonic acid (TNBS) in 50% ethanol. Consequent colonic damage was evaluated pathologically, and cytokine mRNA expression levels in macroscopically inflamed sites were measured by real-time quantitative reverse transcription-polymerase chain reaction. Pretreatment with rhG-CSF remarkably attenuated both the loss of body weight and colonic wall thickening due to progressive transmural inflammation. In the control, treatment with TNBS led to a statistically significant (p < 0.05) upregulation of IFN-gamma mRNA expression in the inflammatory sites measured at post-treatment day 7. In the experimental group, pretreatment with rhG-CSF abrogated transcription of IFN-gamma (p < 0.05), but was not, however, associated with an upregulation of IL-4 or the regulatory cytokines TGF-beta and IL-10. Furthermore, transcription of IL-12p35 (a rate-limiting factor for the production of IL-12) was significantly (p < 0.05) downregulated by rhG-CSF at 24h post-TNBS instillation, whereas IL-12p40 was not affected. Pretreatment with rhG-CSF drastically attenuated the degree of TNBS-induced colitis through selective downregulation of Th1-associated cytokines.


Minimally Invasive Therapy & Allied Technologies | 2010

Scientific assessment of endoscopic surgical skills.

Hiroyuki Egi; Masazumi Okajima; Tomohiro Kawahara; Masanori Yoshimitsu; Daisuke Sumitani; Masakazu Tokunaga; Haruka Takeda; Toshiyuki Itamoto; Hideki Ohdan

Abstract Recently, significant attention has been focused on training and education for safe endoscopic surgery. A new assessment method, the Hiroshima University Endoscopic Surgical Assessment Device (HUESAD), has been designed at Hiroshima University to evaluate the smoothness of the movement of endoscopic instruments from velocity. Experts (with experience in performing more than 100 laparoscopic surgeries) and novices (with no experience in performing laparoscopic surgery) were recruited for this study. The aim of task 1 was to move the tip of the endoscopic instrument on the tops of poles from A to C, and task 2 was to move it from the right pole B to the left pole D. The peak velocity (Vp) and the time when peak velocity appears (Tp) were analyzed. Both the peak velocity (Vp) and the time when peak velocity appears (Tp) to perform task 1 and task 2 were significantly faster in the expert group than in the novice group. The peak velocity (Vp) and the time when peak velocity appears (Tp) in HUESAD, which indicate the smoothnes of the endoscopic procedure, are among the most important factors for assessing endoscopic surgical skills.


World Journal of Surgical Oncology | 2009

Retroperitoneal abscess complicated with necrotizing fasciitis of the thigh in a patient with sigmoid colon cancer

Yuji Takakura; Satoshi Ikeda; Masanori Yoshimitsu; Takao Hinoi; Daisuke Sumitani; Haruka Takeda; Yasuo Kawaguchi; Manabu Shimomura; Masakazu Tokunaga; Masazumi Okajima; Hideki Ohdan

BackgroundNecrotizing fasciitis of the thigh due to the colon cancer, especially during chemotherepy, has not been previously reported.Case presentationA 67-year-old man admitted to the hospital was diagnosed with sigmoid colon cancer that had spread to the left psoas muscle. Multiple hepatic metastases were also found, and combination chemotherapy with irinotecan and S-1 was administered. Four months after the initiation of chemotherapy, the patient developed gait disturbance and high fever and was therefore admitted to the emergency department of our hospital. Blood examination revealed generalized inflammation with a high C-reactive protein level. Computed tomography of the abdomen and pelvis showed gas and fluid collection in the retroperitoneum adjacent to the sigmoid colon cancer. The abscess was locally drained under computed tomographic guidance; however, the infection continued to spread and necrotizing fasciitis developed. Consequently, emergent debridement was performed. The patient recovered well, and the primary tumor was resected after remission of the local inflammation.ConclusionNecrotizing fasciitis of the thigh due to the spread of sigmoid colon cancer is unusual, but this fatal complication should be considered during chemotherapy for patients with unresectable colorectal cancer.


international conference on multimedia computing and systems | 1996

V-QBE: video database retrieval by means of example motion of objects

Atsuo Yoshitaka; Masanori Yoshimitsu; Masahiko Hirakawa; Tadao Ichikawa

Multimedia databases consist of text, static images, sound, and/or video. Video data is considered to be the most informative among those types of data. It conveys the meaning of a scene, the existence and/or motion of certain objects, and others. We present a system that retrieves video data by means of the motions of objects observed in video data in the database. That is, a query for a video database is specified by drawing an example trajectory of an object.


Minimally Invasive Therapy & Allied Technologies | 2012

Approaching time is important for assessment of endoscopic surgical skills

Masakazu Tokunaga; Hiroyuki Egi; Minoru Hattori; Masanori Yoshimitsu; Daisuke Sumitani; Tomohiro Kawahara; Masazumi Okajima; Hideki Ohdan

Abstract This study aimed to verify whether the approaching time (the time taken to reach the target point from another point, a short distance apart, during point-to-point movement in endoscopic surgery), assessed using the Hiroshima University Endoscopic Surgical Assessment Device (HUESAD), could distinguish the skill level of surgeons. Expert surgeons (who had performed more than 50 endoscopic surgeries) and novice surgeons (who had no experience in performing endoscopic surgery) were tested using the HUESAD. The approaching time, total time, and intermediate time (total time – approaching time) were measured and analyzed using the trajectory of the tip of the instrument. The approaching time and total time were significantly shorter in the expert group than in the novice group (p < 0.0001). The intermediate time did not significantly differ between the groups (p > 0.05). The approaching time, which is a component of the total time, is very mportant in the measurement of the total time to assess endoscopic surgical skills. Further, the approaching time was useful for skill assessment by the HUESAD for evaluating the skill of surgeons performing endoscopic surgery.


Journal of Surgical Research | 2012

The Importance of Stressing the Use of Laparoscopic Instruments in the Initial Training for Laparoscopic Surgery Using Box Trainers: A Randomized Control Study

Masakazu Tokunaga; Masazumi Okajima; Hiroyuki Egi; Masanori Yoshimitsu; Daisuke Sumitani; Tomohiro Kawahara; Minoru Hattori; Hideki Ohdan

BACKGROUND The goal of this study was to improve the efficiency of initial box training for laparoscopic surgery. MATERIALS AND METHODS The study used the following task: suturing and knot tying task under a combination of four conditions. (1) The C (use of conventional instruments)-D (direct vision); (2) the C-V (indirect vision via a video monitor); (3) the L (use of laparoscopic instruments)-D; and (4) the L-V (the standard laparoscopic suturing and knot tying). The first study assessed 11 medical students undergoing L-V training. The time to complete each of the four assessment tasks was recorded pre- and post-training. The second study was a randomized, controlled trial involving 36 students grouped according to three types of training methods: the L-D, the C-V, and the L-V group. The improvement in the time to complete the L-V task was assessed and the Hiroshima University Endoscopic Surgical Assessment Device (HUESAD) was used for assessment as well. RESULTS In the first study, a significant improvement in the performance time between pre- and post-training for the L-D task was found, but not for the C-V task. The second study found that the improvement rate of the L-D trained group was significantly greater than that of the C-V and L-V groups. The HUESAD assessment also showed the similar results. CONCLUSIONS A training program stressing the use of laparoscopic instruments and compensating for the fulcrum effect is more effective for novices using box trainers in the initial laparoscopic surgery instruction than one emphasizing performing the tasks via a video monitor.


Transplantation | 2003

Facilitation of tacrolimus-induced heart-allograft acceptability by pretransplant host treatment with granulocyte colony-stimulating factor: interleukin-12-restricted suppression of intragraft monokine mRNA expression.

Teruhiko Kitayama; Keisuke Hayamizu; Hiroyuki Egi; Ichiro Ohmori; Masanori Yoshimitsu; Toshimasa Asahara

Background. Because recombinant human granulocyte colony-stimulating factor (rhG-CSF) is known to modulate function of antigen-presenting cells, we examined effects of pretransplant host treatment with rhG-CSF on allograft survival. Methods. In DA-to-Lewis rat heart transplantation, hosts were given pretransplant injections of rhG-CSF (250 &mgr;g/kg/day subcutaneously from day −5–0) and/or posttransplant injections of tacrolimus (2 mg/kg/day intramuscularly from day 0–3). Cytokine mRNA levels in grafts were measured by real-time reverse-transcription polymerase chain reaction. Results. rhG-CSF pretreatment was effective in prolonging allograft survival only in tacrolimus-treated hosts (P <0.001). Intragraft mRNA expression of interleukin (IL)-12 subunits (p35, p40) at 24 hours after transplantation was significantly (P <0.05) down-regulated by the addition of rhG-CSF and was associated with suppression of interferon-&ggr; levels on day 6, although other proinflammatory cytokines (tumor necrosis factor -&agr;, IL-1&bgr;, IL-6, IL-18) and anti-inflammatory cytokines (IL-10, transforming growth factor-&bgr;) were not. Conclusions. rhG-CSF pretreatment down-regulates intragraft expression of the type-1 T-helper cell (Th1)-driving cytokine IL-12 and facilitates tacrolimus-induced graft acceptance.


Surgery Today | 2014

Inguinal hernia repair with the mesh plug method is safe after radical retropubic prostatectomy.

Hiroaki Niitsu; Junya Taomoto; Koji Mita; Masanori Yoshimitsu; Yoichi Sugiyama; Naoki Hirabayashi; Wataru Takiyama

AbstractPurpose We evaluated the safety and efficiency of using the mesh plug method (MP) to repair inguinal hernias in patients with a history of radical retropubic prostatectomy (RRP). We also investigated how RRP influences the development of inguinal hernias and impacts their repair.Methods Among 488 adult male patients who underwent inguinal hernia repair during a recent 5-year period, 37 had a history of RRP. We compared the characteristics and surgical outcomes of the patients who had undergone RRP (post-RRP group) with those who had not (non-RRP group).ResultsAll post-RRP hernias were treated by MP. The 37 post-RRP patients had a collective 41 hernias, 40 of which were of the indirect type. The side affected by the hernia did not differ significantly between the groups. We compared the short-term surgical outcomes of the indirect post-RRP hernias vs. the indirect non-RPP hernias without recurrence and incarceration. The operation times, postoperative hospital stay, and mobility rates did not differ significantly between the two groups. The blood loss was almost equal in both groups.ConclusionInguinal hernia repair after RRP may be difficult because of inflammatory changes in the preperitoneal cavity, but the surgical outcomes of MP were equivalent in patients with or without a history of RPP in this study. MP is a safe and effective method for post-RPP hernia repair.

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Hiroyuki Egi

Life Sciences Institute

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Naoki Hirabayashi

Wakayama Medical University

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Tomohiro Kawahara

Kyushu Institute of Technology

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