A convolutional neural network for bleeding detection in capsule endoscopy using real clinical data.

BACKGROUND: The goal of the present study was to develop a convolutional neural network for the detection of bleedings in capsule endoscopy videos using realistic clinical data from one single-centre. METHODS: Capsule endoscopy videos from all 133 patients (79 male, 54 female; meanage = 53.73 years, SDage = 26.13) who underwent capsule endoscopy at our institution between January 2014 and August 2018 were screened for pathology. All videos were screened for pathology by two independent capsule experts and confirmed findings were checked again by a third capsule expert. From these videos, 125 pathological findings (individual episodes of bleeding spanning a total of 5696 images) and 103 non-pathological findings (sections of normal mucosal tissue without pathologies spanning a total of 7420 images) were used to develop and validate a neural network (Inception V3) using transfer learning. RESULTS: The overall accuracy of the model for the detection of bleedings was 90.6% [95%CI: 89.4%-91.7%], with a sensitivity of 89.4% [95%CI: 87.6%-91.2%] and a specificity of 91.7% [95%CI: 90.1%-93.2%]. CONCLUSION: Our results show that neural networks can detect bleedings in capsule endoscopy videos under realistic, clinical conditions with an accuracy of 90.6%, potentially reducing reading time per capsule and helping to improve diagnostic accuracy.

Assessment of pyloric sphincter physiology after Ivor-Lewis esophagectomy using an endoluminal functional lumen imaging probe.

OBJECTIVE OF THE STUDY: The most common functional complication after Ivor-Lewis esophagectomy is the delayed emptying of the gastric conduit (DGCE) for which several diagnostic tools are available, e.g. chest X-ray, upper esophagogastroduodenoscopy (EGD) and water-soluble contrast radiogram. However, none of these diagnostic tools evaluate the pylorus itself. Our study demonstrates the successful measurement of pyloric distensibility in patients with DGCE after esophagectomy and in those without it. METHODS AND PROCEDURES: Between May 2021 and October 2021, we performed a retrospective single-centre study of all patients who had an oncological Ivor-Lewis esophagectomy and underwent our post-surgery follow-up programme with surveillance endoscopies and computed tomography scans. EndoFlip™ was used to perform measurements of the pylorus under endoscopic control, and distensibility was measured at 40 ml, 45 ml and 50 ml balloon filling. RESULTS: We included 70 patients, and EndoFlip™ measurement was feasible in all patients. Successful application of EndoFlip™ was achieved in all interventions (n = 70, 100%). 51 patients showed a normal postoperative course, whereas 19 patients suffered from DGCE. Distensibility proved to be smaller in patients with symptoms of DGCE compared to asymptomatic patients. For 40 ml, 45 ml and 50 ml, the mean distensibility was 6.4 vs 10.1, 5.7 vs 7.9 and 4.5 vs 6.3 mm2/mmHg. The differences were significant for all three balloon fillings. No severe EndoFlip™ treatment-related adverse events occurred. CONCLUSION: Measurement with EndoFlip™ is a safe and technically feasible endoscopic option for measuring the distensibility of the pylorus. Our study shows that the distensibility in asymptomatic patients after esophagectomy is significantly higher than that in patients suffering from DGCE. However, more studies need to be conducted to demonstrate the general use of EndoFlip™ measurement of the pylorus after esophagectomy.

Circadian changes in protein-synthesis rate and protein phosphorylation in cell-free extracts of Gonyaulax polyedra.

The polysomal pattern of the dinoflagellate Gonyaulax polyedra, cultured under constant conditions, demonstrates a circadian rhythm. The relative amount of polysomes increases during the phase corresponding to the previous night period (=subjective night phase) when the rate of protein synthesis reaches its maximum (Cornelius et al., 1985, Planta 160, 365-370). Cell-free extracts were isolated at different circadian phase. The rate of protein synthesis in the extracts changed rhythmically in the same manner as the rate of protein synthesis in vivo. Substances in the postribosomal supernatants influenced the protein-synthesis rate of the cell-free system, depending on the phase when they were isolated: "night factors" stimulated protein synthesis in "day extracts" whereas "day factors" inhibited protein synthesis in "night extracts". These effects were abolished by heating the postribosomal supernatant. In-vitro phosphorylation in parallel probes showed changes in the pattern of phosphorylated proteins. Phosphorylation of one of the proteins (95 kDa) was decreased after addition of "night factor(s)" and increased after addition of "day factor(s)". Cyclic-AMP enhanced the rates of protein synthesis and phosphorylation in the day extracts.