Introduction Indigo naturalis (IN) is a blue pigment extracted from Assam indigo and other plants and has been confirmed to be highly effective for ulcerative colitis (UC) treatment in several clinical studies. Objective We conducted a multicenter double-blind study to confirm the efficacy and safety of short-term IN administration. Methods A multicenter, randomized controlled trial was conducted between December 2015 and October 2018 in our facilities. Forty-six patients with mild to moderate active UC (Lichtiger index: 5–10) were randomly assigned to the IN group or the placebo group and received 5 capsules (500 mg) twice a day for 2 weeks. We investigated the efficacy according to blood tests and the Lichtiger index before and after administration, and we also examined adverse events. Results The analysis included 42 patients (20 males, 22 females) with an average age of 45 years. Nineteen patients were assigned to the placebo group, and 23 were assigned to the IN group. After treatment administration, in the placebo group, no change in the Lichtiger index was observed (7.47 to 6.95, p = 0.359), and hemoglobin was significantly reduced (12.7 to 12.4, p = 0.031), while in the IN group, the Lichtiger index (9.04 to 4.48, p = 0.001) and albumin (4.0 to 4.12, p = 0.022) improved significantly. Mild headaches were observed in 5 patients and 1 patient in the IN and placebo groups, respectively. Conclusions Short-term administration of IN is highly effective without serious adverse events such as pulmonary hypertension or intussusception and may prevent the occurrence of serious adverse events.

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Background and study aims Snare devices play an important role in treatment of intestinal polyps. However, there are no objective measurements for the characteristics of the various types of snare devices. Materials and methods Seven types of snare devices from four manufacturers were evaluated based on original measurements. The evaluated factors were stiffness, cutting quality, and change in force required for cutting depending on sheath shape. The latter two factors were evaluated by measuring the force required to cut 20 % gelatin cylinders, which simulated intestinal polyps. The cutting sharpness was evaluated by observing the sectional surface of cut gelatin cylinders using a stereomicroscope. The correlations between these measurements and characteristics of the snare devices were investigated. Results A strong positive correlation, with an R2 value of 0.863, was shown between the force required to cut gelatin cylinders and loop wire diameter. Loop wire diameter also had a strong correlation, with an R2 value of 0.7997, with the change in force required for cutting gelatin cylinders depending on sheath shape. No correlations were detected between loop stiffness and characteristics of snare devices. The edge-enhanced image revealed that the rougher surfaces of the gelatin cylinders were cut by snares with a thicker diameter. Conclusions Thinner loop wire may provide higher performance in cold snare polypectomy in an experimental model.

Background and study aims We developed an e-learning program for endoscopic diagnosis of invasion depth of early gastric cancer (EGC) using a simple diagnostic criterion called non-extension sign, and the contribution of self-study quizzes to improvement of diagnostic accuracy was evaluated. Methods We conducted a prospective randomized controlled study that recruited endoscopists throughout Japan. After completing a pretest, the participants watched video lectures and undertook post-test 1. The participants were then randomly allocated to either the self-study or non-self-study group, and participants in the first group completed the self-study program that comprised 100-case quizzes. Finally, participants in both groups undertook post-test 2. The primary endpoint was the difference in post-test 2 scores between the groups. The perfect score for the tests was set as 100 points. Results A total of 423 endoscopists completed the pretest and were enrolled. Post-test 1 was completed by 415 endoscopists and 208 were allocated to the self-study group and 207 to the non-self-study group. Two hundred and four in the self-study group and 205 in the non-self-study group were included in the analysis. Video lectures improved the mean score of post-test 1 from 72 to 77 points. Participants who completed the self-study quizzes showed significantly better post-test 2 scores compared with the non-self-study group (80 vs. 76 points, respectively, P < 0.0001). Conclusions Our e-learning program showed that self-study quizzes consolidated knowledge of the non-extension sign and improved diagnostic ability of endoscopists for invasion depth of EGC.

Background and study aims Ultrathin endoscopes are commonly used for surveillance esophagogastroduodenoscopy (EGD) to reduce discomfort associated with scope insertion. However, the flexibility of an ultrathin endoscope is a trade-off between reducing discomfort and lengthening examination time. Patients and methods The EG17-J10 (EG17) is a novel ultrathin endoscope characterized by its tapering body stiffness; however, the flexibility of its tip is comparable to that of the traditional ultrathin endoscope EG16-K10 (EG16). We compared EGD examination time between EG17 and EG16. A total of 319 examinees who underwent EGD from November 2019 to January 2020 at the Chiba-Nishi General Hospital were enrolled. Six examinees were excluded due to past history of surgical resection of the upper gastrointestinal tract or too much food residues; 313 examinees (EG17, 209; EG16,104) were retrospectively analyzed. The examination time was divided into three periods: esophageal insertion time (ET), gastroduodenal insertion time (GDT), and surveillance time of the stomach (ST). The total amount of ET, GDT, and ST was defined as total examination time (TT). Results TT of EGD using EG17 was significantly shorter compared to EGD using EG16 (222.7 ± 68.9 vs. 245.7 ± 78.5 seconds) (P = 0.004). Among the three periods of examination time, ET (66.7 ± 24.1 vs. 76.0 ± 24.1 seconds) (P = 0.001) and GDT (47.9 ± 17.4 vs. 55.2 ± 35.2 seconds) (P = 0.007) of EGD using EG17 were significantly shorter compared to EGD using EG16, except for ST (108.1 ± 51.5.1 vs. 114.5 ± 50.1 seconds) (P = 0.148). Conclusion An ultrathin endoscope with tapering body stiffness can shorten EGD examination time, mainly due to the shortening of insertion time.