Factors associated with increased duration of endoscopic submucosal dissection for rectal tumors: a 22-year retrospective analysis.

BACKGROUND AND AIMS: Colorectal endoscopic submucosal dissection (ESD) is widely used in several countries. However, it is associated with technical difficulties. Rectal ESD is considered an intermediate step in colorectal ESD training. Nevertheless, some rectal lesions require a longer procedure time than usual, and the reason for the prolonged time taken for these specific lesions remains unclear. Therefore, this study aimed to clarify the factors associated with prolonged rectal ESD. METHODS: In total, 483 rectal lesions resected using ESD from February 1998 to June 2021 were investigated. Prolonged ESD procedure time was defined as the time from the first submucosal injection to lesion removal exceeding 120 minutes, whereas other procedures were defined as average ESD procedure time. Clinicopathologic and endoscopic findings were compared between the 2 groups using univariate and multivariate analyses. RESULTS: One hundred forty-four lesions were resected using a prolonged ESD procedure time of 202.9 ± 92.3 minutes, whereas 339 lesions were resected using an average ESD procedure time of 77.8 ± 29.4 minutes. Multivariate analysis revealed that tumors involving the dentate line (P = .026), resection size ≥50 mm (P < .001), invasion depth ≥T1b (P = .006), and circumferential range ≥2/3 (P = .001) were independent risk factors for prolonged-duration ESDs, regardless of whether the procedure was performed by an expert or not. CONCLUSIONS: The results of the present study suggest that the location of a lesion involving the dentate line, resection size ≥50 mm, circumferential range ≥2/3, and invasion depth ≥T1b are the independent risk factors for prolonged ESD procedure time.

A prospective randomized study of the use of an ultrathin colonoscope versus a pediatric colonoscope in sedation-optional colonoscopy.

BACKGROUND: Ultrathin colonoscopes (UTC) reportedly produce less pain during colonoscopy than standard colonoscopes. The aim of this study was to assess the tolerability of an UTC compared with that of a pediatric colonoscope. METHODS: A total of 270 adult patients scheduled to undergo colonoscopy were randomized, with 134 allocated to the UTC group and 136 to the pediatric colonoscope group. Pain was assessed using a visual analog scale. For all procedures, sedation was administered only if requested. Overall pain, rate and time of cecal and terminal ileum intubation, number of patients requesting sedation, adenoma detection rates (ADR), and rate of complications were measured and analyzed. RESULTS: Among all patients, the medians of maximum pain and overall pain were significantly lower in the UTC group than in the pediatric colonoscope group (23 vs. 38, P < 0.001; 12 vs. 22, P = 0.0003, respectively). Significantly fewer patients requested sedation in the UTC group than in the pediatric colonoscope group (1.4 vs. 6.6%; P = 0.0269). No significant differences were seen in either the rate and time of successful cecal and terminal ileum intubation, or in other procedure-related outcomes, including ADR. CONCLUSIONS: Compared with a pediatric colonoscope, the UTC was associated with reduced overall and maximum pain during colonoscopy, with no difference in ADR.

Reduced Intravenous Fluorescein Dose for Upper and Lower Gastrointestinal Tract Probe-Based Confocal Laser Endomicroscopy.

BACKGROUND/AIMS: Probe-based confocal laser endomicroscopy (pCLE) requires the administration of intravenous (IV) fluorescein. This study aimed to determine the optimal dose of IV fluorescein for both upper and lower gastrointestinal (GI) tract pCLE. METHODS: Patients 20 to 79 years old with gastric high-grade dysplasia (HGD) or colorectal neoplasms (CRNs) were enrolled in the study. The dose de-escalation method was employed with five levels. The primary endpoint of the study was the determination of the optimal dose of IV fluorescein for pCLE of the GI tract. The reduced dose was determined based on off-line reviews by three endoscopists. An insufficient dose of fluorescein was defined as the dose of fluorescein with which the pCLE images were not deemed to be visible. If all three endoscopists determined that the tissue structure was visible, the doses were de-escalated. RESULTS: A total of 12 patients with gastric HGD and 12 patients with CRNs were enrolled in the study. Doses were de-escalated to 0.5 mg/kg of fluorescein for both non-neoplastic duodenal and colorectal mucosa. All gastric HGD or CRNs were visible with pCLE with IV fluorescein at 0.5 mg/kg. CONCLUSION: In the present study, pCLE with IV fluorescein 0.5 mg/kg was adequate to visualize the magnified structure of both the upper and lower GI tract.

Spindle checkpoint activation at meiosis I advances anaphase II onset via meiosis-specific APC/C regulation.

During mitosis, the spindle assembly checkpoint (SAC) inhibits the Cdc20-activated anaphase-promoting complex/cyclosome (APC/C(Cdc20)), which promotes protein degradation, and delays anaphase onset to ensure accurate chromosome segregation. However, the SAC function in meiotic anaphase regulation is poorly understood. Here, we examined the SAC function in fission yeast meiosis. As in mitosis, a SAC factor, Mad2, delayed anaphase onset via Slp1 (fission yeast Cdc20) when chromosomes attach to the spindle improperly. However, when the SAC delayed anaphase I, the interval between meiosis I and II shortened. Furthermore, anaphase onset was advanced and the SAC effect was reduced at meiosis II. The advancement of anaphase onset depended on a meiosis-specific, Cdc20-related factor, Fzr1/Mfr1, which contributed to anaphase cyclin decline and anaphase onset and was inefficiently inhibited by the SAC. Our findings show that impacts of SAC activation are not confined to a single division at meiosis due to meiosis-specific APC/C regulation, which has probably been evolved for execution of two meiotic divisions.