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Dive into the research topics where Yasuyuki Mitani is active.

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Featured researches published by Yasuyuki Mitani.


Journal of Pediatric Surgery | 2010

Should fundoplication be added at the time of gastrostomy placement in patients who are neurologically impaired

Hisayoshi Kawahara; Yasuyuki Mitani; Keisuke Nose; Hiroshi Nakai; Akihiro Yoneda; Akio Kubota; Masahiro Fukuzawa

BACKGROUND/PURPOSE Patients who have advanced neurologic impairment (NI) and require gastrostomy placement (GP) frequently have symptomatic gastroesophageal reflux. We investigated the outcomes of GP without fundoplication in patients who had NI. METHODS This was a retrospective review of 54 patients with NI (median, 7 years; range, 1-18 years) undergoing GP alone. The operative criteria included medically controllable or no reflux symptoms. The patients were divided into 2 groups based on the percentage of total esophageal time with a pH less than 4.0 (reflux index, or RI): group I (GI, n = 33), RI less than 5.0% (median age, 6 years; range, 2-15 years); group II (GII, n = 21), RI 5.0% or greater (median age, 10 years; range, 1-18 years). Data are expressed as medians and ranges. RESULTS Nutritional management was successfully conducted after GP with or without the administration of lansoprazole, famotidine, or rikkunshito in all but 2 patients. One GI patient with alpha-thalassemia required fundoplication, and one GII patient with Cockayne syndrome required gastrojejunal tube feeding. The RI increased significantly in GI patients (2.1% [0%-4.8%] vs 4.5% [0.2%-11.4%], P = .004), whereas it decreased significantly in GII patients (11.2% [5.9%-41.6%] vs 9.8% [1.05-26.6%], P = .04). CONCLUSION Gastroesophageal reflux and related symptoms rarely deteriorate to require additional treatment after GP in patients with NI. Gastrostomy placement is a less invasive and effective procedure for improving the quality of life in those patients.


British Journal of Surgery | 2015

Randomized clinical trial of defaecatory function after anterior resection for rectal cancer with high versus low ligation of the inferior mesenteric artery

Kenji Matsuda; Tsukasa Hotta; Katsunari Takifuji; Shozo Yokoyama; Yoshimasa Oku; Takashi Watanabe; Yasuyuki Mitani; Junji Ieda; Yuki Mizumoto; Hiroki Yamaue

Defaecatory function is often poor after anterior resection. Denervation of the neorectum following high ligation of the inferior mesenteric artery (IMA) is a possible cause of impaired defaecatory function. The purpose of this randomized clinical trial was to clarify whether the level of ligation of the IMA in patients with rectal cancer affects defaecatory function.


Surgery Today | 2009

Reconstruction of an infected recurrent ventral hernia after a mesh repair using a pedicled tensor fascia lata flap: Report of two cases

Shinya Hayami; Tsukasa Hotta; Katsunari Takifuji; Makoto Iwahashi; Yasuyuki Mitani; Hiroki Yamaue

Recently, the use of prosthetic mesh has revolutionized the repair of ventral hernias. However, the occurrence of infection related with the use of this prosthesis remains an important complication, which may result in occurrence of fistula formation of the skin or intestine, sepsis, or reoccurrence of ventral hernia. This report presents two cases where a pedicled musculocutaneous flap using the tensor fascia lata (pedicled TFL flap) was effective as a treatment for an infectious large abdominal hernia, and reviews the previous literature. Two Japanese men aged 61 and 78 years old underwent a ventral hernia repair using Composix Kugel mesh. They both developed a wound infection with methicillin-resistant Staphylococcus aureus. Conservative therapy was not successful and the defect in the abdominal wall of two patients measured 12 × 21 cm and 7 × 10 cm in length, respectively. Reoperations were performed by removing the infectious mesh and then reconstructing the abdominal wall with the bilateral and left-side pedicled TFL flaps, respectively. No recurrence of the ventral hernia has been recognized for 50 months and 7 months after reoperation, respectively. A review of previous studies showed that no patients treated with a pedicled TFL flap experienced a recurrent hernia. Therefore, the pedicled TFL flap was considered to be effective for infectious large abdominal recurrent hernia.


Journal of Pediatric Surgery | 2009

Influence of thoracoscopic esophageal atresia repair on esophageal motor function and gastroesophageal reflux.

Hisayoshi Kawahara; Hiroomi Okuyama; Yasuyuki Mitani; Motonari Nomura; Keisuke Nose; Akihiro Yoneda; Toshimichi Hasegawa; Akio Kubota; Masahiro Fukuzawa

BACKGROUND/PURPOSE Thoracoscopic repair has recently been attempted in newborns with esophageal atresia (EA), but it remains unclear whether thoracoscopic dissection reduces pathological gastroesophageal reflux. We investigated the influence of a thoracoscopic approach on esophageal motor function in patients with EA. METHODS Clinical and gastrointestinal data of 10 patients with EA with open repair (group A) and 7 with thoracoscopic repair (group B) were analyzed retrospectively. Videomanometry was conducted to investigate esophageal motor patterns. Esophageal acid exposure was evaluated with 24-hour esophageal pH monitoring. Data are expressed as medians and ranges. RESULTS Contractions in the distal esophagus were conspicuously absent in 1 and 3 patients in groups A and B, respectively (P = .26). There were no significant differences in esophageal acid exposure (5.5% [0.7%-24.6%] vs 3.7% [0.3%-56.8%]; P = .71) or mean esophageal acid reflux time (0.5 minutes [0.1-1.4 minutes] vs 0.5 minutes [0.1-1.3 minutes]; P = .87) between the 2 groups. Fundoplication was conducted in 2 patients in each group (P = .60), all of whom had conspicuously absent distal esophageal contractions. Those contractions were preserved in the remaining patients with the exception of 1 group B patient. CONCLUSION There are unlikely to be benefits from thoracoscopic repair of EA in terms of postoperative esophageal motor function.


Acta Haematologica | 2012

Primary anaplastic large cell lymphoma of the psoas muscle: a case report and literature review.

Shinji Kounami; Keiko Shibuta; Megumi Yoshiyama; Yasuyuki Mitani; Takashi Watanabe; Katsunari Takifuji; Norishige Yoshikawa

Primary anaplastic large cell lymphoma (ALCL) of skeletal muscle is very rare. We report a case of ALCL arising from the left psoas muscle. A 14-year-old girl presented with a large left inguinal tumor. She complained of a 2-month history of left leg pain, which had been exacerbated upon leg extension, and she had become aware of a rapidly growing left inguinal tumor 3 weeks before admission. CT scan and MRI revealed a large tumor arising from the left major psoas muscle and protruding into the inguinal region. In view of the tumor’s location and the patient’s age, soft tissue tumors such as rhabdomyosarcoma and primitive neuroectodermal tumor were initially considered. However, histopathological examination yielded a diagnosis of anaplastic lymphoma kinase-positive ALCL. The serum level of soluble interleukin-2 receptor was markedly elevated at 50,414 U/ml, and this also strongly suggested ALCL. Although rarely reported, ALCL is an important entity to consider in the differential diagnosis of skeletal muscle tumors in children and young adults.


PLOS ONE | 2017

Clinical implications of carcinoembryonic antigen distribution in serum exosomal fraction—Measurement by ELISA

Shozo Yokoyama; Akihiro Takeuchi; Shunsuke Yamaguchi; Yasuyuki Mitani; Takashi Watanabe; Kenji Matsuda; Tsukasa Hotta; John E. Shively; Hiroki Yamaue

Background Serum exosomal proteins have great potential as indicators of disease status in cancer, inflammatory or metabolic diseases. The association of a fraction of various serum proteins such as carcinoembryonic antigen (CEA) with circulating exosomes has been debated. The establishment of a method to measure the exosomal fraction of such proteins might help resolve this controversy. The use of enzyme-linked immunosorbent assays (ELISAs) to measure serum exosomal molecules, for example CEA, is rare in research laboratories and totally absent in clinical biology. In this study, we optimized a method for assessment of serum exosomal molecules combining a treatment by volume-excluding polymers to isolate the exosomes, their subsequent solubilization in an assay buffer and ELISA. Methods One hundred sixteen consecutive patients with colorectal cancer were enrolled for this study between June 2015 and June 2016 at Wakayama Medical University Hospital (WMUH). Whole blood samples were collected from patients during surgery. Exosomes were isolated using the ExoQuick reagent, solubilized in an assay buffer and subjected to CEA detection by ELISA. The procedure of serum exosome isolation and the formulation of the assay buffer used for the ELISA were optimized in order to improve the sensitivity and specificity of the assay. Results A five-fold increase in the concentration of the exosomes in the assay buffer (using initial serum volume as a reference) and the addition of bovine serum albumin (BSA) resulted in more accurate measurements of the serum exosomal CEA. The thawing temperature of frozen serum samples before exosome extraction was also optimized. A validation study that included one hundred sixteen patients with colorectal cancer demonstrated that serum exosomal CEA from samples thawed at 25°C exhibited a better AUC value, sensitivity, and specificity as well as a more correct classification than serum CEA. Conclusions We optimized an easy and rapid detection method for assessment of serum exosomal CEA. The thawing temperature of frozen serum prior to exosome extraction, the formulation of the assay buffer used for exosome solubilization and the concentration of the exosomes in this buffer were fine-tuned to enable the appropriate and accurate measurement of serum exosomal CEA.


Cancer Chemotherapy and Pharmacology | 2015

CEACAM1 and hollow spheroid formation modulate the chemosensitivity of colorectal cancer to 5-fluorouracil

Naoyuki Yamamoto; Shozo Yokoyama; Junji Ieda; Yasuyuki Mitani; Shunsuke Yamaguchi; Katsunari Takifuji; Tsukasa Hotta; Kenji Matsuda; Takashi Watanabe; John E. Shively; Hiroki Yamaue

PurposeCarcinoembryonic antigen-related cell adhesion molecule 1 (CEACAM1) re-expressed and promoted hollow spheroid (HS) formation beyond the invasion front of colorectal cancer. The aim of the present study was to clarify whether CEACAM1 cytoplasmic domain isoform balance and HS are associated with resistance to 5-fluorouracil (5FU).MethodsTwo-dimensional (D) or 3D culture systems were employed to evaluate the effects of CEACAM1 cytoplasmic isoform balance and HS formation on the chemosensitivity of colorectal cancer cells to 5FU. The risk factors for postoperative recurrence were calculated based on the presence of HS and various clinicopathological characteristics in 82 patients with Stage III colorectal cancer who had undergone curative surgery followed by 5FU-based chemotherapy.ResultsCEACAM1-4L-transfected HT29 and CEACAM1-4L and 4S expressing parental LS174T cells had significantly higher resistance to 5FU in comparison with CEACAM1-4S- or vector control-transfected cells. In 3D culture, HS formation induced by CEACAM1-4L induced chemoresistance to 5FU, whereas the solid spheres formed in response to CEACAM1-4S were destroyed by 5FU treatment. HS was identified as an independent factor for recurrence of Stage III colorectal cancer after curative resection followed by 5FU-based chemotherapy. Kaplan–Meier survival curves demonstrated that patients with HS had lower recurrence-free survival rate.ConclusionsCEACAM1 long cytoplasmic domain isoform dominance and HS formation are phenotypes associated with chemoresistance to 5FU.


Gastrointestinal Tumors | 2017

Oncological Outcomes following Rectal Cancer Surgery with High or Low Ligation of the Inferior Mesenteric Artery

Kenji Matsuda; Shozo Yokoyama; Tsukasa Hotta; Katsunari Takifuji; Takashi Watanabe; Koichi Tamura; Yasuyuki Mitani; Hiromitsu Iwamoto; Yuki Mizumoto; Hiroki Yamaue

Background: The level of inferior mesenteric artery (IMA) ligation for anterior resection of rectal cancer has several considerations concerning oncological outcomes. The primary endpoint of this randomized controlled trial (RCT) was to assess bowel function between high and low ligation. This study was intended to clarify oncological outcome as the secondary endpoint. Objective: The aim of this study was to assess in a prospective RCT whether the ligation level of the IMA in rectal cancer influences oncological outcomes. Methods: Between February 2008 and December 2011, 100 patients who underwent anterior resection for rectal cancer were randomized to perform either high or low ligation of the IMA. Oncological outcomes was the secondary endpoint of this RCT, whereas assessing bowel function was the primary endpoint. This RCT was registered at clinicaltrials.gov (NCT00701012). Results: There were no differences between the groups in terms of clinical data except for tumor stage. There were more advanced-stage patients in the high ligation group (p = 0.046). There were no lymph node (LN) metastases in the root of the IMA in the high ligation group. The average number of harvested LNs for the high and low ligation groups was 16.7 and 14.9, respectively. There was no difference in disease-free survival (DFS), site of first recurrence, and overall survival (OS). When patients were in stage III, there was also no difference in DFS and OS. Conclusions: The ligation level of the IMA in rectal cancer may not influence oncological outcomes. However, further large-scale RCTs are needed to conclude this issue.


Case reports in hematology | 2015

Neonatal Acute Megakaryoblastic Leukemia Presenting with Leukemia Cutis and Multiple Intracranial Lesions Successfully Treated with Unrelated Cord Blood Transplantation.

Hiroshi Tsujimoto; Shinji Kounami; Yasuyuki Mitani; Takashi Watanabe; Katsunari Takifuji

Neonatal acute megakaryoblastic leukemia (AMKL) without Down syndrome (DS) is an extremely rare disorder. We report of a one-day-old male infant without DS who developed AMKL with leukemia cutis and right facial nerve palsy. Magnetic resonance imaging of the patients brain revealed multiple intracranial tumors. A biopsy specimen of the skin lesion was suggestive of AMKL, but the bone marrow leukemic cells were less than 5% of the marrow nucleated cells. The skin and intracranial lesions had spontaneously regressed within one and a half months, but the patients anemia and thrombocytopenia gradually worsened and the leukemic cells in the bone marrow gradually increased to more than 20% of the nucleated cells. In addition, multiple intracranial lesions reappeared at 72 days of life. We diagnosed the patient with AMKL, and chemotherapy followed by unrelated cord blood transplantation after a reduced-intensity conditioning regimen resulted in sustained complete remission. At present, the patient is well, and he has demonstrated normal development for five years.


Techniques in Coloproctology | 2017

Horizontal rectal transection using an endolinear stapler for laparoscopic low anterior resection

Tsukasa Hotta; Katsunari Takifuji; Shozo Yokoyama; Kenji Matsuda; Junji Ieda; Takashi Watanabe; Koichi Tamura; Yasuyuki Mitani; Hiromitsu Iwamoto; Yoh Takei; Yuki Mizumoto; Ayako Tsumura; M. Deguchi; Hiroki Yamaue

Multiple firings with multiple cartridges for rectal transection have been reported as potential causes of anastomotic leakage in laparoscopic low anterior resection with the double-stapling technique [1]. Here we demonstrate an effective new method for horizontal transection of the rectum that we have used for laparoscopic low anterior resection, using a large endovascular clip for rectal alignment. The patient is placed in the head-down lithotomy position with the right side tilted down and the surgeon on the patient’s right. Five-port trocars including two 12-mm ports, two 5-mm ports, and a blunt port were introduced (Fig. 1). Pneumoperitoneum is created using carbon dioxide, and laparoscopic exploration is performed. After complete mobilization of the rectum to the levators, the surgeon inserts the linear stapler through the right lower quadrant port (Fig. 2a, b). The assistant through the left upper quadrant port pulls the rectum forward and cranially rolling it in a counterclockwise direction. The surgeon through the right upper quadrant port also rolls the rectum in a counterclockwise direction to align the horizontal line of the rectum with the linear staple insertion line (Fig. 2c, d). A 70-mm endovascular clip (B. Braun Aesculap Co., Tokyo, Japan) is introduced through the right lower quadrant port aligning, and the rectal wall is clamped below the tumor (Figs. 2e, 3a). Figure 3b shows the 70-mm endovascular clip. A distal rectal washout is performed using 1000 ml of 5% povidone-iodine solution. An endolinear stapler (Echelon FLEX 60 ; Ethicon EndoSurgery, Cincinnati, OH, USA) is inserted through the right lower quadrant port and then applied at the rectal wall parallel and caudal to the 70-mm endovascular clip (Fig. 3c). The assistant forceps in the left lower quadrant port pushes the distal rectum to the right, and the endolinear stapler with opened jaws is simultaneously pushed deeper into the left side space. The jaws are then closed at a position that enabled transection of the rectum with one firing using a single cartridge (Fig. 3d). Figure 3e shows Fig. 1 Port sites

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Hiroki Yamaue

Wakayama Medical University

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Katsunari Takifuji

Wakayama Medical University

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Takashi Watanabe

Wakayama Medical University

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Shozo Yokoyama

Wakayama Medical University

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Tsukasa Hotta

Wakayama Medical University

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Kenji Matsuda

Wakayama Medical University

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Junji Ieda

Wakayama Medical University

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Hiromitsu Iwamoto

Wakayama Medical University

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Yuki Mizumoto

Wakayama Medical University

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