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Dive into the research topics where Nobuyuki Ehira is active.

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Featured researches published by Nobuyuki Ehira.


Annals of Hematology | 2005

Randomized study of Helicobacter pylori eradication therapy and proton pump inhibitor monotherapy for idiopathic thrombocytopenic purpura

Yutaka Tsutsumi; Hiroe Kanamori; Hiroaki Yamato; Nobuyuki Ehira; Takahito Kawamura; Shintaro Umehara; Akio Mori; Shinji Obara; Nobutaka Ogura; Junji Tanaka; Masahiro Asaka; Masahiro Imamura; Nobuo Masauzi

Helicobacter pylori (HP) eradication therapy is a useful treatment for idiopathic thrombocytopenic purpura (ITP). Some investigators have also reported the effects of proton pump inhibitor (PPI) monotherapy on ITP. We performed a randomized study of HP eradication therapy and PPI monotherapy on ITP. Four of nine patients achieved complete remission (CR), two of nine achieved partial remission (PR) in HP eradication therapy, three of eight achieved CR, and two of eight achieved PR in PPI monotherapy. No significant differences were observed in the CR + PR of these patients between HP eradication therapy and PPI monotherapy. As for cost comparisons, HP eradication therapy is cheaper than PPI monotherapy, but it is less effective.


Journal of Hepato-biliary-pancreatic Sciences | 2011

Preoperative biliary drainage for hilar cholangiocarcinoma: which stent should be selected?

Hiroshi Kawakami; Satoshi Kondo; Masaki Kuwatani; Hiroaki Yamato; Nobuyuki Ehira; Taiki Kudo; Kazunori Eto; Shin Haba; Joe Matsumoto; Kentaro Kato; Takahiro Tsuchikawa; Eiichi Tanaka; Satoshi Hirano; Masahiro Asaka

The controversy over whether and how to perform preoperative biliary drainage (PBD) in patients with hilar cholangiocarcinoma (HCA) remains unsettled. Arguments against PBD before pancreatoduodenectomy have recently been gaining momentum. However, the complication-related mortality rate is as high as 10% for patients with HCA who have undergone major liver resection, and liver failure is a major cause of postoperative death. This suggests the need for PBD to treat jaundice in HCA patients scheduled for major surgical resection of the liver and that major surgery should be performed only after the recovery of hepatic function. No definite criteria or guidelines outlining indications for PBD are currently available. In patients with HCA, PBD may be performed by either percutaneous transhepatic biliary drainage (PTBD) or endoscopic biliary drainage (EBD). No consensus, however, has been reached regarding which drainage method is more appropriate. No reported study has compared the effectiveness of PTBD, endoscopic biliary stenting (EBS), and endoscopic nasobiliary drainage (ENBD) in patients with HCA. This review summarizes the results of our study comparing the three methods and outlines the preoperative endoscopic management of segmental cholangitis (SC) in HCA patients undergoing PBD.


World Journal of Gastroenterology | 2011

Three cases of retroperitoneal schwannoma diagnosed by EUS-FNA.

Taiki Kudo; Hiroshi Kawakami; Masaki Kuwatani; Nobuyuki Ehira; Hiroaki Yamato; Kazunori Eto; Kanako Kubota; Masahiro Asaka

Schwannomas are peripheral nerve tumors that are typically solitary and benign. Their diagnosis is largely based on surgically resected specimens. Recently, a number of case reports have indicated that retroperitoneal schwannomas could be diagnosed with endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA). We report the diagnosis of three cases of schwannoma using EUS-FNA. Subjects were two males and one female, ages 22, 40, and 46 years, respectively, all of whom were symptom-free. Imaging findings showed well-circumscribed round tumors. However, as the tumors could not be diagnosed using these findings alone, EUS-FNA was performed. Hematoxylin-eosin staining of the resulting tissue fragments revealed bland spindle cells with nuclear palisading. There was no disparity in nuclear sizes. Immunostaining revealed S-100 protein positivity and all cases were diagnosed as schwannomas. Ki-67 indexes were 3%-15%, 2%-3%, and 3%, respectively. No case showed any signs of malignancy. As most schwannomas are benign tumors and seldom become malignant, we observed these patients without therapy. All tumors demonstrated no enlargement and no change in characteristics. Schwannomas are almost always benign and can be observed following diagnosis by EUS-FNA.


World Journal of Gastroenterology | 2014

Influence of the safety and diagnostic accuracy of preoperative endoscopic ultrasound-guided fine-needle aspiration for resectable pancreatic cancer on clinical performance

Taiki Kudo; Hiroshi Kawakami; Masaki Kuwatani; Kazunori Eto; Shuhei Kawahata; Yoko Abe; Manabu Onodera; Nobuyuki Ehira; Hiroaki Yamato; Shin Haba; Kazumichi Kawakubo; Naoya Sakamoto

AIM To evaluate the safety and diagnostic accuracy of endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) in a cohort of pancreatic cancer patients. METHODS Of 213 patients with pancreatic cancer evaluated between April 2007 and August 2011, 82 were thought to have resectable pancreatic cancer on the basis of cross-sectional imaging findings. Of these, 54 underwent EUS-FNA before surgery (FNA+ group) and 28 underwent surgery without preoperative EUS-FNA (FNA- group). RESULTS All 54 lesions were visible on EUS, and all 54 attempts at FNA were technically successful. The diagnostic accuracy according to cytology and histology findings was 98.1% (53/54) and 77.8% (42/54), respectively, and the total accuracy was 98.1% (53/54). One patient developed mild pancreatitis after EUS-FNA but was successfully treated by conservative therapy. No severe complications occurred after EUS-FNA. In the FNA+ and FNA- groups, the median relapse-free survival (RFS) was 742 and 265 d, respectively (P = 0.0099), and the median overall survival (OS) was 1042 and 557 d, respectively (P = 0.0071). RFS and OS were therefore not inferior in the FNA+ group. These data indicate that the use of EUS-FNA did not influence RFS or OS, nor did it increase the risk of peritoneal recurrence. CONCLUSION In patients with resectable pancreatic cancer, preoperative EUS-FNA is a safe and accurate diagnostic method.


Journal of Experimental & Clinical Cancer Research | 2010

An embryo-specific expressing TGF-β family protein, growth-differentiation factor 3 (GDF3), augments progression of B16 melanoma

Nobuyuki Ehira; Hiroyuki Oshiumi; Misako Matsumoto; Takeshi Kondo; Masahiro Asaka; Tsukasa Seya

Malignant tumor cells often express embryonic antigens which share the expression with embryonic stem (ES) cells. The embryonic antigens are usually encoded by ES cell-specific genes, a number of which are associated with tumorigenesis and/or tumor progression. We examined the expression of ES cell-specific genes in the mouse B16 melanoma cell line to identify the factors promoting tumorigenesis. We found that endogenous growth-differentiation factor 3 (GDF3) expression was induced in implant B16 tumor during tumor progression in syngenic C57BL/6 mice. B16 F10, a subline with a high metastatic potential, continuously expressed GDF3 while low metastatic B16 F1 expressed comparatively decreased levels of GDF3. Overexpression of GDF3 promoted growth of implanted melanoma B16 F1 and F10 in syngenic mice. Ectopic expression of GDF3 was accompanied by an increased level of production of CD24/CD44. Such a profile was reported to be characteristic of melanoma stem cell-like cells. GDF3 expression was observed in embryonal carcinomas, primary testicular germ cell tumors, seminomas and breast carcinomas. However, the role of GDF3 in these cancers remains undetermined. Overexpression of GDF3 did not affect the growth of mouse hepatoma high or low metastatic sublines G5 or G1, both of which do not express GDF3. Since GDF3-driven CD24 acts as a receptor for endogenous innate immune ligands that modulate cell proliferation, CD24 is an effective determinant of tumorigenesis in malignant cell transformation. Finally, our results support the view that GDF3 has the ability to induce progression of CD24-inducible melanoma in mice.


Endoscopy | 2011

Portobiliary fistula: unusual complication of wire-guided cannulation during endoscopic retrograde cholangiopancreatography.

Hiroshi Kawakami; Masaki Kuwatani; Taiki Kudo; Nobuyuki Ehira; Hiroaki Yamato; Masahiro Asaka

Title Portobiliary fistula: unusual complication of wire-guided cannulation during endoscopic retrograde cholangiopancreatography. Author(s) Kawakami, Hiroshi; Kuwatani, Masaki; Kudo, Taiki; Ehira, Nobuyuki; Yamato, Hiroaki; Asaka, Masahiro Citation Endoscopy, 43(Suppl 2: UCTN (Unusual cases and technical notes)), E98-E99 https://doi.org/10.1055/s-0030-1256150 Issue Date 2011-03-18 Doc URL http://hdl.handle.net/2115/48575 Rights


Journal of Hepato-biliary-pancreatic Sciences | 2015

Single‐stage endoscopic treatment for mild to moderate acute cholangitis associated with choledocholithiasis: a multicenter, non‐randomized, open‐label and exploratory clinical trial

Kazunori Eto; Hiroshi Kawakami; Shin Haba; Hiroaki Yamato; Toshinori Okuda; Kei Yane; Tsuyoshi Hayashi; Nobuyuki Ehira; Manabu Onodera; Ryusuke Matsumoto; Yu Matsubara; Tomofumi Takagi; Naoya Sakamoto

Two‐stage treatment involving stone removal after drainage is recommended for mild to moderate acute cholangitis associated with choledocholithiasis. However, single‐stage treatment has some advantages. We aimed to assess the efficacy and safety of single‐stage endoscopic treatment for mild to moderate acute cholangitis associated with choledocholithiasis.


World Journal of Gastrointestinal Endoscopy | 2016

Lower incidence of complications in endoscopic nasobiliary drainage for hilar cholangiocarcinoma.

Kazumichi Kawakubo; Hiroshi Kawakami; Masaki Kuwatani; Shin Haba; Taiki Kudo; Yoko Taya; Shuhei Kawahata; Yoshimasa Kubota; Kimitoshi Kubo; Kazunori Eto; Nobuyuki Ehira; Hiroaki Yamato; Manabu Onodera; Naoya Sakamoto

AIM To identify the most effective endoscopic biliary drainage technique for patients with hilar cholangiocarcinoma. METHODS In total, 118 patients with hilar cholangiocarcinoma underwent endoscopic management [endoscopic nasobiliary drainage (ENBD) or endoscopic biliary stenting] as a temporary drainage in our institution between 2009 and 2014. We retrospectively evaluated all complications from initial endoscopic drainage to surgery or palliative treatment. The risk factors for biliary reintervention, post-endoscopic retrograde cholangiopancreatography (post-ERCP) pancreatitis, and percutaneous transhepatic biliary drainage (PTBD) were also analyzed using patient- and procedure-related characteristics. The risk factors for bilateral drainage were examined in a subgroup analysis of patients who underwent initial unilateral drainage. RESULTS In total, 137 complications were observed in 92 (78%) patients. Biliary reintervention was required in 83 (70%) patients. ENBD was significantly associated with a low risk of biliary reintervention [odds ratio (OR) = 0.26, 95%CI: 0.08-0.76, P = 0.012]. Post-ERCP pancreatitis was observed in 19 (16%) patients. An absence of endoscopic sphincterotomy was significantly associated with post-ERCP pancreatitis (OR = 3.46, 95%CI: 1.19-10.87, P = 0.023). PTBD was required in 16 (14%) patients, and Bismuth type III or IV cholangiocarcinoma was a significant risk factor (OR = 7.88, 95%CI: 1.33-155.0, P = 0.010). Of 102 patients with initial unilateral drainage, 49 (48%) required bilateral drainage. Endoscopic sphincterotomy (OR = 3.24, 95%CI: 1.27-8.78, P = 0.004) and Bismuth II, III, or IV cholangiocarcinoma (OR = 34.69, 95%CI: 4.88-736.7, P < 0.001) were significant risk factors for bilateral drainage. CONCLUSION The endoscopic management of hilar cholangiocarcinoma is challenging. ENBD should be selected as a temporary drainage method because of its low risk of complications.


European Journal of Haematology | 2004

Effectiveness of propagermanium treatment in multiple myeloma patients

Yutaka Tsutsumi; Junji Tanaka; Hiroe Kanamori; Mio Musashi; Hiina Minami; Arata Fukushima; Hiroaki Yamato; Nobuyuki Ehira; Takahito Kawamura; Shinji Obara; Nobutaka Ogura; Masahiro Asaka; Masahiro Imamura; Nobuo Masauzi

Interferon (IFN) is one of several drugs effective in treating multiple myeloma (MM), and propagermanium is an IFN inducer. We report on 10 MM patients who were treated with propagermanium at doses from 10 to 40 mg. Two patients achieved complete remission (CR), two patients achieved partial remission (PR), and the condition of four patients was stable (stable disease, SD). After discontinuation of propagermanium, the status of MM progressed in two patients who were in SD and in two patients who had achieved PR. The administration of propagermanium was restarted in one patient resulting in a decrease in her paraprotein.


Gut and Liver | 2014

Safety and Utility of Single-Session Endoscopic Ultrasonography and Endoscopic Retrograde Cholangiopancreatography for the Evaluation of Pancreatobiliary Diseases

Kazumichi Kawakubo; Hiroshi Kawakami; Masaki Kuwatani; Shin Haba; Taiki Kudo; Yoko Abe; Shuhei Kawahata; Manabu Onodera; Nobuyuki Ehira; Hiroaki Yamato; Kazunori Eto; Naoya Sakamoto

Endoscopic ultrasound (EUS) and endoscopic retrograde cholangiopancreatography (ERCP) are essential for diagnosing and treating pancreatobiliary diseases. Single-session EUS and ERCP are considered to be essential in reducing the duration of hospital stays; however, complications are a primary concern. The aim of this study was to evaluate the safety and efficacy of single-session EUS and ERCP. Sixty-eight patients underwent single-session EUS and ERCP at a tertiary referral center between June 2008 and December 2012. We retrospectively reviewed patient data from a prospectively maintained EUS-ERCP database and evaluated the procedural characteristics and complications. Thirty-eight patients (56%) underwent diagnostic EUS, and 30 patients (44%) underwent EUS fine-needle aspiration, which had an overall accuracy of 100%. Sixty patients (89%) underwent therapeutic ERCP, whereas the remaining eight procedures were diagnostic. Thirteen patients underwent biliary stone extraction, and 48 underwent biliary drainage. The median total procedural time was 75 minutes. Complications were observed in seven patients (10%). Six complications were post-ERCP pancreatitis, which were resolved using conservative management. One patient developed Mallory-Weiss syndrome, which required endoscopic hemostasis. No sedation-related cardiopulmonary complications were observed. Single-session EUS and ERCP provided accurate diagnosis and effective management with a minimal complication rate.

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