Publications by authors named "Naoto Tamai"

Background And Study Aims: Prophylactic clip closure after colorectal endoscopic submucosal dissection (ESD) among patients on anticoagulants is of uncertain effectiveness in reducing delayed bleeding (DB) risk. We aimed to assess the effect of prophylactic clip closure in preventing DB after colorectal ESD among patients on anticoagulants.

Patients And Methods: We used the ABCD-J study database, a large-scale multicenter study analyzing DB among 34,455 colorectal ESD cases from 47 Japanese institutions.

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In colloidal quantum dots (QDs), excitons are confined within nanoscale dimensions, and the relaxation of hot electrons occurs through Auger cooling. The behavior of hot electrons is evident under ambient pressure. Nanocrystal characteristics, including their size, are key to determining hot electron behavior because they serve as the stage.

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Objectives: Endoscopic closures of mucosal defects following endoscopic resection can be challenging and time-consuming. The novel through-the-scope suture device has demonstrated acceptable closure times, but its learning curve is still unknown. This study aims to evaluate the number of cases required to achieve competency in this device.

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Background: Colorectal cancer (CRC) is a major concern because of its increasing incidence and mortality worldwide. Therefore, effective screening strategies are necessary to reduce its incidence.

Summary: In addition to fecal immunochemical tests and computed tomography colonography, screening colonoscopy is expected to significantly contribute to the reduction of CRC.

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There is robust evidence to indicate a strong correlation between the bowel preparation status and adenoma detection rate (ADR), which directly impacts the incidence and mortality rate of postcolonoscopy colorectal cancer. Therefore, improving bowel preparation has been of increasing interest. In Japan, commercially available bowel preparation agents include polyethylene glycol, oral sodium sulfate, sodium picosulfate-magnesium citrate, magnesium citrate, and oral sodium phosphate; each has its own strengths and limitations.

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Closure of mucosal defects following colorectal endoscopic submucosal dissection (C-ESD) is often performed to prevent post-C-ESD adverse events. However, large mucosal defect closure using conventional clips remains technically challenging. Here, we evaluated the feasibility of the novel endoclip with anchor prongs, called the MANTIS Clip (Boston Scientific, Tokyo, Japan), for mucosal defect closure after C-ESD.

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Colonoscopy is the gold standard for detecting and resecting adenomas or early stage cancers to reduce the incidence and mortality rates of colorectal cancer. In a recent observational study, texture and color enhancement imaging (TXI) was reported to improve polyp detection during colonoscopy. This randomized controlled trial involving six Japanese institutions aims to confirm the superiority of TXI over standard white-light imaging (WLI) in detecting colorectal lesions during colonoscopy.

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Single-photon emissions from individual emitters are crucial in fundamental science and quantum information technologies. Multichromophoric systems, comprising multiple dyes, can exhibit single-photon emissions through efficient annihilation between the excited states; however, exploring this phenomenon in complex systems remains a challenge. In this study, we investigated the photon statistics of emissions from multiple perylene bisimide (PBI) dyes adsorbed onto the surface of CdSe/ZnS quantum dots (QDs).

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Article Synopsis
  • Texture and color enhancement imaging (TXI) improves the visibility of gastric neoplasms compared to traditional white light imaging (WLI), using both conventional and newly developed endoscopes.
  • A study involved patients with gastric neoplasms, where endoscopists scored the visibility of these neoplasms under different imaging modalities, revealing TXI provided significantly better visibility than WLI.
  • Overall, using the newer endoscopes led to better visibility scores across all imaging types, highlighting TXI's effectiveness without any specific factors affecting its benefits.
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Article Synopsis
  • The study analyzed delayed bleeding rates after colorectal endoscopic submucosal dissection in patients taking direct oral anticoagulants (DOACs) and compared them to patients on warfarin.
  • Among different DOACs, dabigatran had the highest delayed bleeding rate, whereas rivaroxaban showed a significantly lower rate than warfarin.
  • Risk factors for delayed bleeding in the DOAC group included heparin bridging therapy, rectal lesion location, and longer procedure times.
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Intramolecular singlet fission (iSF) is an efficient strategy of multiexciton generation via a singlet exciton splitting into a correlated triplet pair in one organic molecule with more than two chromophores. Propeller-shaped iptycene-linked triisopropylsilyl(TIPS)-ethynyl functionalized pentacene oligomers (pent-monomer, pent-dimer, and pent-trimer) were synthesized, and the iSF dynamics of pent-dimer and -trimer were monitored by a visible-near-IR transient absorption (TA) spectroscopy. Quantum yields of the triplet pair, ∼80%, of both estimated by near-IR TA spectral analysis are in good agreement with the results of global analysis and triplet sensitization experiments.

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Objectives: We aimed to evaluate the efficacy of texture and color enhancement imaging (TXI), which allows the acquisition of brighter images with enhanced color and surface structure in colorectal polyp detection compared to white light imaging.

Methods: Patients who underwent colonoscopy with repeated ascending colon observation using TXI and white light imaging between August 2020 and January 2021 were identified in three institutions. The outcomes included the mean number of adenomas detected per procedure (MAP), adenoma detection rate (ADR), and ascending colonic adenoma miss rate (Ac-AMR).

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Objective: To evaluate the visibility of colorectal lesions using a novel image processing algorithm, texture and color enhancement imaging (TXI), that allows the acquisition of brighter images with enhanced color and surface structure.

Methods: During August-September 2019, patients referred for endoscopic treatment were prospectively recruited. Electronic data acquired while observing colorectal lesions using white light imaging (WLI) were obtained and recorded: WLI, TXI mode1 (with color enhancement), and TXI mode2 (without color enhancement) videos were constructed.

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Obesity causes multiple conditions such as type 2 diabetes, cardiovascular disease, and so on, and an intervention is needed for controlling weight and improving metabolic syndrome. However, the effectiveness of lifestyle interventions and pharmacotherapy are restrictive for losing weight. Endoscopic sleeve gastroplasty (ESG) was developed as a new therapy, picking the best of both medication and surgery, less invasive and more effective.

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Background: Endoscopic submucosal dissection (ESD) is technically difficult and requires considerable training. The authors have developed a multi-loop traction device (MLTD), a new traction device that offers easy attachment and detachment. We aimed to evaluate the utility of MLTD in ESD.

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Texture and color enhancement imaging (TXI) has been developed as an image-enhanced endoscopy technology. TXI mode2 enhances texture and brightness, and TXI mode1 also enhances color. This study aims to assess the color differences in squamous cell carcinoma (SCC) suspicious lesions in the pharynx and esophagus using white light imaging (WLI), TXI mode1, TXI mode2, and narrow-band imaging (NBI).

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We developed a computer-aided detection (CADe) system to detect and localize colorectal lesions by modifying You-Only-Look-Once version 3 (YOLO v3) and evaluated its performance in two different settings. The test dataset was obtained from 20 randomly selected patients who underwent endoscopic resection for 69 colorectal lesions at the Jikei University Hospital between June 2017 and February 2018. First, we evaluated the diagnostic performances using still images randomly and automatically extracted from video recordings of the entire endoscopic procedure at intervals of 5 s, without eliminating poor quality images.

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Background: We have developed the computer-aided detection (CADe) system using an original deep learning algorithm based on a convolutional neural network for assisting endoscopists in detecting colorectal lesions during colonoscopy. The aim of this study was to clarify whether adenoma miss rate (AMR) could be reduced with CADe assistance during screening and surveillance colonoscopy.

Methods: This study was a multicenter randomized controlled trial.

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The Colonoscopy Screening and Surveillance Guidelines were developed by the Japan Gastroenterological Endoscopy Society as basic guidelines based on the scientific methods. The importance of endoscopic screening and surveillance for both detection and post-treatment follow-up of colorectal cancer has been recognized as essential to reduce disease mortality. There is limited high-level evidence in this field; therefore, we had to focus on the consensus of experts.

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Coherent acoustic phonon vibrations of Au nanopolyhedrons, including nanocubes, nano-octahedrons, and nanocuboctahedrons, in aqueous solutions and poly(vinyl alcohol) (PVA) films, were investigated using transient absorption (TA) spectroscopy combined with finite element analysis based on continuum elastic theory. In each type of nanopolyhedron, two vibrational modes with similar quality factors (Qs) and phases were observed, suggesting that both were induced by thermal expansion. The low-frequency vibrational mode represents a tip-to-tip displacement in each nanopolyhedron, whereas the high-frequency mode is the breathing vibration of the whole particle and reveals morphology dependence, displaying a face-to-face displacement in nanocuboctahedrons, an edge-to-edge displacement in nano-octahedrons, and a combination of face-to-face and edge-to-edge displacements in nanocubes.

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Objectives: To compare the efficacy and safety of oral sulfate solution administered using the same-day dose and the split-dose regimens with those of polyethylene glycol plus ascorbate solution, used for bowel preparation in Japanese patients undergoing colonoscopy.

Methods: This multicenter (n = 13), randomized, active-controlled, colonoscopist- and image evaluator-blinded, noninferiority study with parallel-group comparison recruited 632 patients from December 2018 to June 2019. Of these, 602 patients were divided into the oral sulfate solution same-day dose group (n = 200); oral sulfate solution split-dose group (n = 202); and polyethylene glycol plus ascorbate same-day dose group (n = 200).

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Background: Blood group O of ABO blood group system is considered as a risk factor for various bleeding events, but the relationship with endoscopic treatment-associated bleeding has yet to be investigated. This study aimed to evaluate whether blood group O is associated with delayed bleeding after colorectal endoscopic resection.

Methods: This was a retrospective observational study based on medical records at four university hospitals in Japan.

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