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The presence of atrophic gastritis (AG) and intestinal metaplasia (IM) is associated with an increased risk of gastric cancer (GC). Thus, the development of new strategies to improve AG/IM is essential for reducing the incidence of GC.We aimed to evaluate the efficacy of rebamipide for improving AG/IM.This was a prospective, randomized, pilot study from a single tertiary referral center. Fifty-three (rebamipide, n = 34 vs. placebo, n = 19) patients, who underwent endoscopic resection for gastric dysplasia or early GC, were analyzed. We obtained tissue samples from the antrum and corpus of the stomach, at the time of screening and 1-year later. The histologic grading of inflammation was performed by histopathologists RESULTS: The AG grade in the antrum improved significantly after rebamipide treatment (pre-administration, 1.870 ± 0.932 vs. post-administration, 1.430 ± 0.986; P = 0.013). Additionally, the severity of IM in the antrum was significantly improved (pre-administration, 1.750 ± 0.963 vs. post-administration, 1.370 ± 1.032; P = 0.038). The rebamipide subgroup analysis revealed that patients with no Helicobacter pylori (HP) infection showed significant improvements in AG in the antrum (pre-administration, 1.880 ± 1.040 vs. post-administration, 1.250 ± 0.894; P = 0.028) and IM in antrum (pre-administration, 1.840 ± 1.012 vs. post-administration, 1.180 ± 0.912; P = 0.020).This study demonstrated that the administration of rebamipide improves AG and IM in the antrum, especially in patients with HP non-infection (KCT0001915).

The inappropriate selection of patients with early gastric cancer (EGC) for endoscopic submucosal dissection (ESD) may lead to additional surgery because of a non-curative resection. This study was performed to assess the accuracy of clinical decisions in ESD for EGC. A total of 607 cases of EGC treated by ESD were prospectively enrolled from January 2011 to June 2014 at a single academic hospital. The 607 EGCs were divided into three groups (overestimated, same-estimated, and underestimated) based on pre-procedure endoscopic findings (indication) and pathological diagnosis after ESD (criteria). We evaluated the discrepancy rates between pre-procedure indication and pathological criteria, and then analyzed the pre-procedure factors that could influence the occurrence of the discrepancies. The absolute, expanded, and beyond the expanded indication has its accuracy on curability criteria in 87%, 77.6%, and 55.6% of cases, respectively. The ratio of overall indication-criteria discrepancies was 250/607 (41.2%). The curability was significantly lower in the underestimated group compared to the overestimated and same-estimated groups (41.6% vs. 94.6%, 94.4%, p

After endoscopic submucosal dissection (ESD) for early gastric cancer (EGC), negative pathological findings cause concern about the adequacy of the procedure and local recurrence after ESD. To investigate the incidence of local recurrence in cases with negative pathological findings after ESD for EGC and pathologically complete resection (CR) during long-term follow-up. We reviewed 453 patients who underwent ESD for ECG from January 2007 to December 2010, respectively. Of these patients, in 17 cases the pathology results confirmed no residual tumor (NRT), and in 421 cases they showed CR in the ESD specimen. Finally, 17 NRT and 358 CR cases were followed up during surveillance. Patient characteristics, endoscopic and pathological data were analyzed for risk factors of local recurrence. We also re-evaluated the pathology of the NRT group to identify hidden malignant cells in the previous ESD specimens. There was no difference between the two groups in terms of recurrence during follow-up surveillance (median 55.7 months). Late local recurrence of EGC was found in two cases (11.8%) in the NRT group, and three early local recurrences (5.6%) were found in the CR group. A review of the pathology in the NRT group revealed hidden malignant cells in five patients (29.4%). Even when the pathological report indicates NRT after ESD, it might be necessary to re-evaluate ESD specimens with a width

Open converted cholecystectomy could occur in patients who planned for laparoscopic cholecystectomy after endoscopic removal of choledocholithiasis.To evaluate the risk factors associated with open converted cholecystectomy.The data for all patients who underwent cholecystectomy after endoscopic removal of choledocholithiasis were retrospectively reviewed. Factors predictive for conversion to open cholecystectomy were analyzed.The rate of open converted cholecystectomy was 15.7 %. In multivariate analysis, cholecystitis (OR 1.908, 95 % CI 1.390-6.388, p = 0.005), mechanical lithotripsy (OR 6.129, 95 % CI 1.867-20.123, p0.005), and two or more choledocholithiases (OR 2.202, 95 % CI 1.097-4.420, p = 0.026) revealed significant risk factors for conversion to open cholecystectomy. Analyzing the risk factors for open converted cholecystectomy according to duration from endoscopic stone removal to cholecystectomy (within 2 weeks, between 2 and 6 weeks, and beyond 6 weeks), acute cholangitis (OR 3.374, 95 % CI 1.267-8.988, p = 0.015), cholecystitis (OR 3.127, 95 % CI 1.100-8.894, p = 0.033), and mechanical lithotripsy (OR 17.504, 95 % CI 3.548-86.355, p0.005) were related to open converted cholecystectomy in ≤2 weeks group.For patients who need cholecystectomy after endoscopic removal of choledocholithiasis, endoscopic retrograde cholangiography-related factors predictive for open converted cholecystectomy are helpful in planning the appropriate timing of surgery.

Gastric atypical cell (GAC), an indefinite pathologic finding, often requires repeated biopsy or other diagnostic treatments, such as endoscopic mucosal resection (EMR), endoscopic submucosal dissection (ESD), or operation (OP). The aim of this study was to analyze the initial endoscopic and histologic findings of GAC and to discuss the necessity of EMR/ESD at establishing a correct diagnosis. This retrospective study enrolled 96 patients proven as GAC on index forceps biopsy. ESD (17/96, 17.7 %), EMR (5/96, 5.2 %), OP (20/96, 20.8 %), and other treatment or follow-up (54/96, 56.3 %) were performed. We analyzed the initial endoscopic and histologic characteristics of GAC lesions, predictive of neoplasm. After diagnostic modalities, the final pathologic diagnoses were cancer (36/96, 37.6 %), dysplasia (9/96, 9.4 %), and non-neoplasm (51/96, 53.0 %). In univariate analysis, age [odds ratio (OR) 1.04, 95 % confidence interval (CI) 1.01–1.07], lesion size of 10 mm or greater (OR 3.94, 95 % CI 1.61–9.61), lesion with depressed type (OR 2.50, 95 % CI 1.09–5.72), and presence of H. pylori (OR 2.83, 95 % CI 1.11–7.25) were risk factors for neoplasm. In multivariate analysis, lesion size of 10 mm or greater (OR 3.63, 95 % CI 1.23–10.66), lesion with depressed type (OR 2.86, 95 % CI 1.11–7.38) were independent risk factors for cancer. Considering the neoplastic risk of GAC, which could be missed on biopsy, more comprehensive tissue sampling via EMR/ESD might be necessary to establish a definite diagnosis.

The effect of In on the structural and optical properties of InxGa1−xN/GaN multiple quantum wells (MQWs) was investigated. These were five-period MQWs grown on sapphire by metalorganic chemical vapor deposition. Increasing the In composition caused broadening of the high-resolution x-ray diffraction superlattice satellite peak and the photoluminescence-excitation bandedge. This indicates that the higher In content degrades the interface quality because of nonuniform In incorporation into the GaN layer. However, the samples with higher In compositions have lower room temperature (RT) stimulated (SE) threshold densities and lower nonradiative recombination rates. The lower RT SE threshold densities of the higher In samples show that the suppression of nonradiative recombination by In overcomes the drawback of greater interface imperfection.

We report on an experimental study of microstructure-based lasing in an optically pumped GaN/AlGaN separate confinement heterostructure (SCH). We achieved low-threshold ultra-violet lasing in optically pumped GaN/AlGaN separate confinement heterostructures over a wide temperature range. The spacing, directionality, and far-field patterns of the lasing modes are shown to be the result of microcavities that were naturally formed in the structures due to strain relaxation. The temperature sensitivity of the lasing wavelength was found to be twice as low as that of bulk-like GaN films. Based on these results, we discuss possibilities for the development of ultra-violet laser diodes with increased temperature stability of the emission wavelength.

We report a comprehensive study on the optical properties of GaN- and AlGaN-based lasing structures at high-levels of optical excitation (carrier densities of 1017−1020 cm−3) and identify critical issues necessary for the development of near- and deep-UV light emitting devices. We successfully achieved room temperature stimulated emission (SE) with emission wavelengths ranging from 351 nm to 373 nm in a variety of samples. Through an analysis of the temperature-dependent lasing characteristics, combined with absorption and time-resolved photoluminescence measurements, we estimated the carrier density required to achieve the SE threshold in GaN epilayers. We found that in AlGaN epilayers, the onset of SE (∼1019 cm−3) occurs at carrier densities one order of magnitude higher than in thick GaN epilayers, indicating that an electron-hole plasma is the dominant gain mechanism over the entire temperature range studied (10 K to 300 K). A remarkably low lasing threshold was observed in GaN/AlGaN heterostructures over the temperature range of 10 K to 300 K. Our experimental results indicate that GaN/AlGaN heterostructures could be used to efficiently generate laser emission with wavelengths shorter than 373 nm. The implications of this study on the development of UV laser diodes is discussed.

The effect of In on the structural and optical properties of InxGa1−xN/GaN multiple quantum wells (MQWs) was investigated. These were five-period MQWs grown on sapphire by metalorganic chemical vapor deposition. Increasing the In composition caused broadening of the high-resolution x-ray diffraction superlattice satellite peak and the photoluminescence-excitation bandedge. This indicates that the higher In content degrades the interface quality because of nonuniform In incorporation into the GaN layer. However, the samples with higher In compositions have lower room temperature (RT) stimulated (SE) threshold densities and lower nonradiative recombination rates. The lower RT SE threshold densities of the higher In samples show that the suppression of nonradiative recombination by In overcomes the drawback of greater interface imperfection.

We report on an experimental study of microstructure-based lasing in an optically pumped GaN/AlGaN separate confinement heterostructure (SCH). We achieved low-threshold ultra-violet lasing in optically pumped GaN/AlGaN separate confinement heterostructures over a wide temperature range. The spacing, directionality, and far-field patterns of the lasing modes are shown to be the result of microcavities that were naturally formed in the structures due to strain relaxation. The temperature sensitivity of the lasing wavelength was found to be twice as low as that of bulk-like GaN films. Based on these results, we discuss possibilities for the development of ultra-violet laser diodes with increased temperature stability of the emission wavelength.