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Hirohisa Machida

Bio: Hirohisa Machida is an academic researcher from Osaka City University. The author has contributed to research in topics: Capsule endoscopy & Double-balloon enteroscopy. The author has an hindex of 25, co-authored 72 publications receiving 3264 citations.


Papers
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Journal ArticleDOI
TL;DR: The results of clinical tests in colonoscopy and esophagoscopy indicated that NBI will be useful as a supporting method for observation of the endoscopic findings of early cancer.
Abstract: This study was performed to examine the usefulness of medical endoscopic imaging utilizing narrow-band illumination. The contrast between the vascular pattern and the adjacent mucosa of the underside of the human tongue was measured using five narrow-band illuminations and three broadband illuminations. The results demon- strate that the pathological features of a vascular pattern are depen- dent on the center wavelength and the bandwidth of illumination. By utilizing narrow-band illumination of 415630 nm, the contrast of the capillary pattern in the superficial layer was markedly improved. This is an important benefit that is difficult to obtain with ordinary broad- band illumination. The appearances of capillary patterns on color im- ages were evaluated for three sets of filters. The narrow, band imaging (NBI) filter set (415630 nm, 445630 nm, 500630 nm) was selected to achieve the preferred appearance of the vascular patterns for clini- cal tests. The results of clinical tests in colonoscopy and esophagos- copy indicated that NBI will be useful as a supporting method for observation of the endoscopic findings of early cancer. © 2004 Society of

858 citations

Journal ArticleDOI
TL;DR: It is suggested that in the examination of colonic lesions the NBI system provides imaging features additional to those of both conventional endoscopy and chromoendoscopy.
Abstract: BACKGROUND AND STUDY AIMS A newly developed narrow-band imaging (NBI) technique, in which modified optical filters were used in the light source of a video endoscope system, was applied during colonoscopy in a clinical setting. This pilot study evaluated the clinical feasibility of the NBI system for evaluating colorectal lesions. PATIENTS AND METHODS A total of 43 colorectal lesions in 34 patients were included in the study. The quality of visualization of colorectal lesions and the accuracy of differentiation between neoplastic and non-neoplastic lesions using the NBI system were evaluated in comparison with results from conventional colonoscopy and with chromoendoscopy. RESULTS For pit pattern delineation, NBI was superior to conventional endoscopy (P < 0.001), but inferior to chromoendoscopy (P < 0.05). NBI achieved better visualization of the mucosal vascular network and of the hue of lesions than conventional endoscopy (P < 0.05). However there was no significant difference between NBI and chromoendoscopy in differentiating neoplastic from non-neoplastic lesions (both techniques had a sensitivity of 100 % and a specificity 75 %). This was better than the results of conventional colonoscopy (sensitivity 83 %, specificity 44 %; P < 0.05 for specificity). CONCLUSIONS These results suggest that in the examination of colonic lesions the NBI system provides imaging features additional to those of both conventional endoscopy and chromoendoscopy. For distinguishing neoplasms from non-neoplastic lesions, NBI was equivalent to chromoendoscopy.

518 citations

Journal ArticleDOI
TL;DR: The Japan NBI Expert Team was constituted with the aim of establishing a universal NBI magnifying endoscopic classification for colorectal tumors (JNET classification) in 2011, and consensus was reached on this classification using the modified Delphi method in June 2014.
Abstract: Many clinical studies on narrow-band imaging (NBI) magnifying endoscopy classifications advocated so far in Japan (Sano, Hiroshima, Showa, and Jikei classifications) have reported the usefulness of NBI magnifying endoscopy for qualitative and quantitative diagnosis of colorectal lesions. However, discussions at professional meetings have raised issues such as: (i) the presence of multiple terms for the same or similar findings; (ii) the necessity of including surface patterns in magnifying endoscopic classifications; and (iii) differences in the NBI findings in elevated and superficial lesions. To resolve these problems, the Japan NBI Expert Team (JNET) was constituted with the aim of establishing a universal NBI magnifying endoscopic classification for colorectal tumors (JNET classification) in 2011. Consensus was reached on this classification using the modified Delphi method, and this classification was proposed in June 2014. The JNET classification consists of four categories of vessel and surface pattern (i.e. Types 1, 2A, 2B, and 3). Types 1, 2A, 2B, and 3 are correlated with the histopathological findings of hyperplastic polyp/sessile serrated polyp (SSP), low-grade intramucosal neoplasia, high-grade intramucosal neoplasia/shallow submucosal invasive cancer, and deep submucosal invasive cancer, respectively.

362 citations

Journal ArticleDOI
TL;DR: A new illumination method for a medical endoscope: narrow band imaging (NBI), in which the spectral bandwidth of the filtered light is narrowed, which has been shown that NBI can enhance the capillary pattern and the crypt pattern on the mucosa.
Abstract: We propose a new illumination method for a medical endoscope: narrow band imaging (NBI), in which the spectral bandwidth of the filtered light is narrowed. To confirm how the spectral specifications of the filtered light influence a reproduced image, an experiment was conducted observing the endoscopic images of the back mucosa of a human tongue. In addition, the effect of NBI on endoscopic images was investigated through preliminary clinical tests in colonoscopy and upper gastrointestinal endoscopy. It has been shown that NBI can enhance the capillary pattern and the crypt pattern on the mucosa. These patterns are useful features for diagnosing an early cancer.

287 citations

Journal ArticleDOI
TL;DR: Low-dose enteric-coated aspirin frequently damages the small intestine, and misoprostol is effective in the treatment of aspirin-induced enteropathy.

163 citations


Cited by
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Journal ArticleDOI
TL;DR: This Guideline is an official statement of the European Society of Gastrointestinal Endoscopy and addresses the roles of small-bowel capsule endoscope and device-assisted enteroscopy for diagnosis and treatment ofsmall-bowe disorders.
Abstract: Small-bowel capsule endoscopy (SBCE) 1 ESGE recommends that prior to SBCE patients ingest a purgative (2 L of polyethylene glycol [PEG]) for better visualization. Strong recommendation, high quality evidence. However, the optimal timing for taking purgatives is yet to be established. 2 ESGE recommends that SBCE should be performed as an outpatient procedure if possible, since completion rates are higher in outpatients than in inpatients. Strong recommendation, moderate quality evidence. 3 ESGE recommends that patients with pacemakers can safely undergo SBCE without special precautions. Strong recommendation, low quality evidence. 4 ESGE suggests that SBCE can also be safely performed in patients with implantable cardioverter defibrillators and left ventricular assist devices. Weak recommendation, low quality evidence. 5 ESGE recommends the acceptance of qualified nurses and trained technicians as prereaders of capsule endoscopy studies as their competency in identifying pathology is similar to that of medically qualified readers. The responsibility of establishing a diagnosis must however remain with the attending physician. Strong recommendation, moderate quality evidence. 6 ESGE recommends observation in cases of asymptomatic capsule retention. Strong recommendation, moderate quality evidence. In cases where capsule retrieval is indicated, ESGE recommends the use of device-assisted enteroscopy as the method of choice. Strong recommendation, moderate quality evidence. Device-assisted enteroscopy (DAE) 1 ESGE recommends performing diagnostic DAE as a day-case procedure in patients without significant underlying co-morbidities; in patients with co-morbidities and/or those undergoing a therapeutic procedure, an inpatient stay is recommended. Strong recommendation, low quality evidence The choice between different settings also depends on sedation protocols. Strong recommendation, low quality evidence. 2 ESGE suggests that conscious sedation, deep sedation, and general anesthesia are all acceptable alternatives: the choice between them should be governed by procedure complexity, clinical factors, and local organizational protocols. Weak recommendation, low quality evidence. 3 ESGE recommends that the findings of previous diagnostic investigations should guide the choice of insertion route. Strong recommendation, moderate quality evidence. If the location of the small-bowel lesion is unknown or uncertain, ESGE recommends that the antegrade route should be generally preferred. Strong recommendation, low quality evidence. In the setting of massive overt bleeding, ESGE recommends an initial antegrade approach. Strong recommendation, low quality evidence. 4 ESGE recommends that, for balloon-assisted enteroscopy (i. e., single-balloon enteroscopy [SBE] and double-balloon enteroscopy [DBE]), small-bowel insertion depth should be estimated by counting net advancement of the enteroscope during the insertion phase, with confirmation of this estimate during withdrawal. Strong recommendation, low quality evidence. ESGE recommends that, for spiral enteroscopy, insertion depth should be estimated during withdrawal. Strong recommendation, moderate quality evidence. Since the calculated insertion depth is only a rough estimate, ESGE recommends placing a tattoo to mark the identified lesion and/or the deepest point of insertion. Strong recommendation, low quality evidence. 5 ESGE recommends that all endoscopic therapeutic procedures can be undertaken at the time of DAE. Strong recommendation, moderate quality evidence. Moreover, when therapeutic interventions are performed, additional specific safety measures are needed to prevent complications. Strong recommendation, high quality evidence.

680 citations

Journal ArticleDOI
TL;DR: The anatomy of the intestinal barrier is discussed and the available methods to evaluate its function are explained, which may improve the current understanding of the gut barrier, and provide a step forward towards personalised medicine.
Abstract: Introduction: The gastrointestinal mucosa constitutes a critical barrier where millions of microbes and environmental antigens come in close contact with the host immune system. Intestinal barrier defects have been associated with a broad range of diseases and therefore denote a new therapeutic target.Areas covered: This review is based on an extensive literature search in PubMed of how the intestinal barrier contributes to health and as a trigger for disease. It discusses the anatomy of the intestinal barrier and explains the available methods to evaluate its function. Also reviewed is the importance of diet and lifestyle factors on intestinal barrier function, and three prototypes of chronic diseases (inflammatory bowel disease, celiac disease and nonalcoholic fatty liver disease) that have been linked to barrier defects are discussed.Expert commentary: The intestinal barrier has been investigated by various methods, but correlation of results across studies is difficult, representing a major sh...

612 citations

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TL;DR: NBI could be the standard examination for the early detection of superficial cancer in the H&N region and the esophagus between conventional white light imaging and NBI in high-risk patients.
Abstract: Purpose Most of the esophageal squamous cell carcinomas (ESCCs) and cancers of the head and neck (HN 97% v 55%, P < .001, respectively). The sensitivity ...

559 citations

Journal ArticleDOI
TL;DR: The pathogenesis of H. pylori and the mechanisms it uses to promote persistent colonization of the gastric mucosa are discussed, with a focus on recent insights into the role of the virulence factors vacuolating cytotoxin (VacA), cytot toxin-associated gene A (CagA) and CagL.
Abstract: The bacterial pathogen Helicobacter pylori has co-evolved with humans and colonizes approximately 50% of the human population, but only causes overt gastric disease in a subset of infected hosts. In this Review, we discuss the pathogenesis of H. pylori and the mechanisms it uses to promote persistent colonization of the gastric mucosa, with a focus on recent insights into the role of the virulence factors vacuolating cytotoxin (VacA), cytotoxin-associated gene A (CagA) and CagL. We also describe the immunobiology of H. pylori infection and highlight how this bacterium manipulates the innate and adaptive immune systems of the host to promote its own persistence.

531 citations