Issues to be Considered for Learning Curve for Peroral Endoscopic Myotomy

Hironari Shiwaku,Haruhiro Inoue 대한소화기내시경학회 2021 Clinical Endoscopy Vol.54 No.5

COMMENTARY

Development of New Soft Actuator Using Magnetic Intelligent Fluids for Flexible Walking Robot

Hironari Taniguchi,Masaki Miyake,Koichi Suzumori 제어로봇시스템학회 2010 제어로봇시스템학회 국제학술대회 논문집 Vol.2010 No.10

The purpose of my work is to develop a new soft actuator with magnetic intelligent fluids such as a magnetic fluid and a magneto-rheological fluid for flexible walking robots. For this purpose, the authors have produced two types of soft magnetic materials. One is called the magnetic fluid rubber that consists of an isoparaffin-based magnetic fluid and elastic silicone rubber. The other is called the magneto-rheological fluid rubber that consists of a polyalphaolefin-based magneto-rheological fluid and elastic silicone rubber. We have developed four types of cylindrical soft actuators using proposed soft magnetic materials. An experimental system was constructed and a response test was made using it. A Laser displacement sensor was employed to find the relationships between the magnetic flux density and the displacement of soft actuator. The experiment showed that the responsibility of soft actuator with the magnetic fluid rubber indicated the best performance. In addition, we operated four electromagnetic coils to control the direction and the displacement of soft actuator. As a result, we have succeeded in moving the tip of soft actuator like drawing a circle. We represented a first possible step towards the development of soft actuator with magnetic functional fluids for flexible walking robots.

A “Back Light System” for Identification of Sites for Endoscopic Ultrasound-Guided Fine-Needle Aspiration in Solid Pancreatic Masses: A Prospective, Randomized Study with a Crossover Design

Ryo Harada,Hironari Kato,Soichiro Fushimi,Hirofumi Inoue,Daisuke Uchida,Yutaka Akimoto,Takeshi Tomoda,Kazuyuki Matsumoto,Yasuhiro Noma,Naoki Yamamoto,Shigeru Horiguchi,Koichiro Tsutsumi,Hiroyuki Okada 대한소화기내시경학회 2019 Clinical Endoscopy Vol.52 No.4

Background/Aims: We applied a back light system (BLS) with a magnifying glass to improve the ability to assess the adequacy ofspecimen sampling using endosonography. We conducted this study to evaluate the effcacy of the BLS in sampling of specimens byendoscopic ultrasound-guided fine needle aspiration of solid pancreatic masses. Methods: This was a prospective, randomized, crossover, single-center clinical trial. An endosonographer evaluated adequacy on grossvisual inspection and identified whitish specimen sampling sites with and without the BLS according to a randomization sequence inthe first and second passes with a 25-G needle. On cytological evaluation, the presence of well-defined pancreatic ductal epithelium wasevaluated by a cytopathologist who was blinded to any clinical information. Results: A total of 80 consecutive patients were eligible during the study period. Adequacy was observed for 52 specimens (65%) withthe BLS and 54 (68%) without the BLS (p=0.88). In assessment of specimen adequacy on gross examination, only fair agreement wasobserved both with and without BLS (kappa score 0.40 and 0.29, respectively). Conclusions: The BLS did not influence the ability to identify specimen sampling sites or reliable assessment of specimen site adequacyusing gross visual inspection.

Utility of Endoscopic Ultrasound-Guided Fine Needle Aspiration in the Diagnosis of Local Recurrence of Pancreaticobiliary Cancer after Surgical Resection

Kazuyuki Matsumoto,Hironari Kato,Shigeru Horiguchi,Takeshi Tomoda,Akihiro Matsumi,Yuki Ishihara,Yosuke Saragai,Saimon Takada,Shinichiro Muro,Daisuke Uchida,Hiroyuki Okada 거트앤리버 소화기연관학회협의회 2020 Gut and Liver Vol.14 No.5

Background/Aims: Endoscopic ultrasound (EUS)-guided fine needle aspiration (FNA; EUS-FNA) allows for diagnostic tissue specimens from various regions to be analyzed. However, diagnosing recurrent pancreaticobiliary cancer after surgery is sometimes difficult. We evaluated the efficacy of EUS-FNA in the diagnosis of local recurrence of pancreaticobiliary cancer and analyzed the factors associated with falsenegative results. Methods: Fifty-one consecutive patients who underwent EUS-FNA due to suspected recurrence of pancreaticobiliary cancer after surgery in an academic center were retrospectively analyzed. The criteria for EUS-FNA were a resected margin or remnant pancreas mass, round swollen lymph node (≥10 mm in diameter), and soft-tissue enhancement around a major artery. Patients with suspected liver metastasis or malignant ascites were excluded. Results: Thirty-nine of the 51 patients had pancreatic cancer; the remaining 12 had biliary cancer. The target sites for EUS-FNA were the soft tissue around a major artery (n=22, 43%), the resected margin or remnant pancreas (n=12, 24%), and the lymph nodes (n=17, 33%). The median size of the suspected recurrent lesions was 15 mm (range, 8 to 40 mm). The overall sensitivity, specificity and accuracy of EUS-FNA for the diagnosis of recurrence was 84% (32/38), 100% (13/13), and 88% (45/51), respectively. FNA of the soft tissue around major arteries (odds ratio, 8.23; 95% confidence interval, 1.2 to 166.7; p=0.033) was significantly associated with a falsenegative diagnosis in the multivariate analysis. Conclusions: EUS-FNA is useful for diagnosing recurrent cancer, even after pancreaticobiliary surgery. The diagnoses of recurrence at soft-tissue sites should be interpreted with caution.

Impact of a Newly Developed Short Double-Balloon Enteroscope on Stent Placement in Patients with Surgically Altered Anatomies

( Koichiro Tsutsumi ),( Hironari Kato ),( Hiroyuki Okada ) 대한소화기학회 2017 Gut and Liver Vol.11 No.2

A newly developed short double-balloon enteroscope with a working channel enlarged to a diameter of 3.2 mm is a novel innovation in stent placement for patients with surgi-cally altered anatomies. Herein, we report three patients in whom this new scope contributed to an efficient technique and ideal treatment. In the first case, the double guidewire technique was efficient and effective for multiple stent place-ments. In the second case, covered self-expandable metal stent (SEMS) placement, which is the standard treatment for malignant biliary obstruction, could be performed in a technologically sound and safe manner. In the third case, SEMS placement was performed as palliative treatment for malignant afferent-loop obstruction; this procedure could be performed soundly and safely using the through-the-scope technique. The wider working channel of this new scope also facilitates a smoother accessory insertion and high suction performance, which reduces procedure time and stress on endoscopists. Furthermore, this new scope, which has advanced force transmission, adaptive bending, and a smaller turning radius, is expected to be highly successful in both diagnosis and therapy for various digestive diseases in patients with surgically altered anatomies. (Gut Liver 2017;11:306-311)

Fabrication and evaluation of various types of micro one-way valves through micro rubber molding process

Yuki UOHASHI,Koichi SUZUMORI,Hironari TANIGUCHI 대한기계학회 2010 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.24 No.1

In recent years, research and development on micro fluid systems has become active in the fields of chemical technology and biotechnology. For the realization of these micro fluid systems, micro fluid devices such as micro-valves and micro pumps are very important. This paper reports the fabrication and experimental evaluation of several micro one-way valves. The valves are fabricated through a micro molding process, which makes the fabrication process simple and suitable for mass production. The experimental results indicate that the developed valve has great performance with a normal flow rate of 130.2 ml/min and a leak flow of 2.2 ml/min. The normal flow rate is 1.4 times higher than that of the previous model.

Comparison of Bilateral and Trisegment Drainage in Patients with High-Grade Hilar Malignant Biliary Obstruction: A Multicenter Retrospective Study

Matsumoto Kazuyuki,Kato Hironari,Morimoto Kosaku,Miyamoto Kazuya,Saragai Yosuke,Kawamoto Hirofumi,Okada Hiroyuki 거트앤리버 소화기연관학회협의회 2023 Gut and Liver Vol.17 No.1

Background/Aims: Bilateral endoscopic drainage with self-expanding metallic stent (SEMS) can be used to effectively manage hilar malignant biliary obstruction. However, the benefits of using a trisegment drainage method remain unknown. Methods: This study retrospectively reviewed the data of 125 patients with Bismuth type IIIa or IV unresectable malignant strictures who underwent bilateral endoscopic drainage using SEMSs at four tertiary centers. The patients were divided into the bilateral and trisegment drainage groups for comparison. The primary endpoint was stent patency and the secondary endpoints were technical success, technical and clinical success of reintervention, and overall survival. Results: The technical success rates of the bilateral and trisegment drainage groups were 95% (34/36) and 90% (80/89) (p=0.41), respectively, with median stent patency durations of 226 and 170 days (p=0.26), respectively. Although the technical success of reintervention was not significantly different between the two groups (p=0.51), the clinical success rate of reintrvention was significantly higher in the trisegment drainage group (73% [11/15] vs 96% [47/49], p=0.009). The median survival times were 324 and 323 days in the bilateral and trisegment drainage groups, respectively (p=0.72). Multivariate Cox hazards model revealed no stent patency-associated factor; however, chemotherapy was associated with longer survival. Conclusions: Although no significant difference was noted with respect to stent patency, significantly higher clinical success rates were achieved with reintervention using the trisegment drainage method than using the bilateral drainage method alone.

Diagnostic Ability of Convex-Arrayed Endoscopic Ultrasonography for Major Vascular Invasion in Pancreatic Cancer

Yuki Fujii,Kazuyuki Matsumoto,Hironari Kato,Yosuke Saragai,Saimon Takada,Sho Mizukawa,Shinichiro Muro,Daisuke Uchida,Takeshi Tomoda,Shigeru Horiguchi,Noriyuki Tanaka,Hiroyuki Okada 대한소화기내시경학회 2019 Clinical Endoscopy Vol.52 No.5

Background/Aims: This study aimed to examine the diagnostic ability of endoscopic ultrasonography (EUS) for major vascularinvasion in pancreatic cancer and to evaluate the relationship between EUS findings and pathological distance. Methods: In total, 57 consecutive patients who underwent EUS for pancreatic cancer before surgery were retrospectively reviewed. EUSimage findings were divided into four types according to the relationship between the tumor and major vessel (types 1 and 2: invasion,types 3 and 4: non-invasion). We also compared the EUS findings and pathologically measured distances between the tumors andevaluated vessels. Results: The sensitivity, specificity, and accuracy of EUS diagnosis for vascular invasion were 89%, 92%, and 91%, respectively, in theveins and 83%, 94%, and 93%, respectively, in the arteries. The pathologically evaluated distances of cases with type 2 EUS findings weresignificantly shorter than those of cases with type 3 EUS findings in both the major veins (median [interquartile range], 96 [0–742] µmvs. 2,833 [1,076–5,694] µm, p=0.012) and arteries (623 [0–854] µm vs. 3,097 [1,396–6,000] µm, p=0.0061). All cases with a distance of≥1,000 µm between the tumors and main vessels were correctly diagnosed. Conclusions: Tumors at a distance ≥1,000 µm from the main vessels were correctly diagnosed by EUS.

Structure and Photoreaction of Photoactive Yellow Protein

Imamoto, Yasushi,Harigai, Miki,Shimizu, Nobutaka,Kamikubo, Hironari,Yamazaki, Yoichi,Kataoka, Mikio Korean Society of Photoscience 2002 Journal of Photosciences Vol.9 No.2

The chromophore/protein interactions in the photocycle intermediates of photoactive yel- low protein (PYP) were probed by site-directed mutagenesis. The absorption spectra of L- intermediates produced from E46Q, T50V, and R52Q mutants were calculated using the absorption spectra of dark states and difference absorption spectra between L-intermediates and dark states, and compared with that of PYP$\_$L/. The absorption spectrum of R52Q$\_$L/ agreed with that of PYP$\_$L/, but those of E46Q$\_$L/ and T50V$\_$L/ were red-shifted. The effect of these mutations on the absorption spectrum for L-intermediate was comparable to that for the dark state, suggesting that the interaction around the phe-nolic oxygen of the chromophore is conserved in PYP$\_$L/ unlike the crystal structure. On the other hand, we have reported that the absorption spectra of Y 42F$\_$M/, T50V $\_$M/, and R52Q$\_$M/ agreed with that of PYP$\_$M/, but that of E46Q$\_$M/ was red-shifted, suggesting that the hydrogen bond of the chromophore with Glu46 is conserved but that with Tyr42 is broken in PYP$\_$M/. These results suggest that the chromophore inter-acts with Glu46 throughout the photocycle, but never directly interacts with Arg52. This model con- flicts with some of the structural model of PYP intermediates proposed based on the high-resolution X -ray crystallography.

Development of Dilated Esophagus, Sigmoid Esophagus, and Esophageal Diverticulum in Patients With Achalasia: Japan Achalasia Multicenter Study

Hiroki Sato,Yusuke Fujiyoshi,Hirofumi Abe,Hironari Shiwaku,Junya Shiota,Chiaki Sato,Hiroyuki Sakae,Masaki Ominami,Yoshitaka Hata,Hisashi Fukuda,Ryo Ogawa,Jun Nakamura,Tetsuya Tatsuta,Yuichiro Ikebuchi 대한소화기 기능성질환∙운동학회 2022 Journal of Neurogastroenterology and Motility (JNM Vol.28 No.2

Background/AimsPatients with achalasia-related esophageal motility disorders (AEMDs) frequently present with dilated and sigmoid esophagus, and develop esophageal diverticulum (ED), although the prevalence and patients characteristics require further elucidation. MethodsWe conducted a multicenter cohort study of 3707 patients with AEMDs from 14 facilities in Japan. Esophagography on 3682 patients were analyzed. ResultsStraight (n = 2798), sigmoid (n = 684), and advanced sigmoid esophagus (n = 200) were diagnosed. Multivariate analysis revealed that long disease duration, advanced age, obesity, and type I achalasia correlate positively, whereas severe symptoms and integrated relaxation pressure correlate negatively with development of sigmoid esophagus. In contrast, Grade II dilation (3.5-6.0 cm) was the most common (52.9%), while grade III dilation (≥ 6 cm) was rare (5.0%). We found early onset, male, obesity, and type I achalasia correlated positively, while advanced age correlated negatively with esophageal dilation. Dilated and sigmoid esophagus were found mostly in types I and II achalasia, but typically not found in spastic disorders. The prevalence of ED was low (n = 63, 1.7%), and non-dilated esophagus and advanced age correlated with ED development. Patients with right-sided ED (n = 35) had a long disease duration (P = 0.005) with low integrated relaxation pressure values (P = 0.008) compared with patients with left-sided ED (n = 22). Patients with multiple EDs (n = 6) had lower symptom severity than patients with a single ED (P = 0.022). ConclusionsThe etiologies of dilated esophagus, sigmoid esophagus, and ED are considered multifactorial and different. Early diagnosis and optimal treatment of AEMDs are necessary to prevent these conditions.