Selective-plane-activation structured illumination microscopy.

The background light from out-of-focus planes hinders resolution enhancement in structured illumination microscopy when observing volumetric samples. Here we used selective plane illumination and reversibly photoswitchable fluorescent proteins to realize structured illumination within the focal plane and eliminate the out-of-focus background. Theoretical investigation of the imaging properties and experimental demonstrations show that selective plane activation is beneficial for imaging dense microstructures in cells and cell spheroids.

Visualization of trans homophilic interaction of clustered protocadherin in neurons.

Clustered protocadherin (Pcdh) functions as a cell recognition molecule through the homophilic interaction in the central nervous system. However, its interactions have not yet been visualized in neurons. We previously reported PcdhγB2-Förster resonance energy transfer (FRET) probes to be applicable only to cell lines. Herein, we designed γB2-FRET probes by fusing FRET donor and acceptor fluorescent proteins to a single γB2 molecule and succeeded in visualizing γB2 homophilic interaction in cultured hippocampal neurons. The γB2-FRET probe localized in the soma and neurites, and FRET signals, which were observed at contact sites between neurites, eliminated by ethylene glycol tetraacetic acid (EGTA) addition. Live imaging revealed that the FRET-negative γB2 signals rapidly moved along neurites and soma, whereas the FRET-positive signals remained in place. We observed that the γB2 proteins at synapses rarely interact homophilically. The γB2-FRET probe might allow us to elucidate the function of the homophilic interaction and the cell recognition mechanism.

Comparison of clinical utility of deep learning-based systems for small-bowel capsule endoscopy reading.

BACKGROUND AND AIM: Convolutional neural network (CNN) systems that automatically detect abnormalities from small-bowel capsule endoscopy (SBCE) images are still experimental, and no studies have directly compared the clinical usefulness of different systems. We compared endoscopist readings using an existing and a novel CNN system in a real-world SBCE setting. METHODS: Thirty-six complete SBCE videos, including 43 abnormal lesions (18 mucosal breaks, 8 angioectasia, and 17 protruding lesions), were retrospectively prepared. Three reading processes were compared: (A) endoscopist readings without CNN screening, (B) endoscopist readings after an existing CNN screening, and (C) endoscopist readings after a novel CNN screening. RESULTS: The mean number of small-bowel images was 14 747 per patient. Among these images, existing and novel CNN systems automatically captured 24.3% and 9.4% of the images, respectively. In this process, both systems extracted all 43 abnormal lesions. Next, we focused on the clinical usefulness. The detection rates of abnormalities by trainee endoscopists were not significantly different across the three processes: A, 77%; B, 67%; and C, 79%. The mean reading time of the trainees was the shortest during process C (10.1 min per patient), followed by processes B (23.1 min per patient) and A (33.6 min per patient). The mean psychological stress score while reading videos (scale, 1-5) was the lowest in process C (1.8) but was not significantly different between processes B (2.8) and A (3.2). CONCLUSIONS: Our novel CNN system significantly reduced endoscopist reading time and psychological stress while maintaining the detectability of abnormalities. CNN performance directly affects clinical utility and should be carefully assessed.

Is proton-pump inhibitor effective in preventing postoperative bleeding after esophageal endoscopic submucosal dissection?

Although proton-pump inhibitor (PPI) administration was reported to be effective in preventing delayed bleeding after gastric endoscopic submucosal dissection (ESD), its effectiveness in esophageal ESD is still unknown. We assessed whether PPI or vonoprazan administration was effective in preventing posterior hemorrhage after esophageal ESD. This retrospective cohort study used the Japanese Diagnosis Procedure Combination (DPC) database, and patients who underwent esophageal ESD between January 2012 and December 2020 were enrolled. The participants were divided into two groups: patients who were prescribed PPI or vonoprazan (PPI or vonoprazan group) and those who were not prescribed PPI (no acid suppression). Propensity score matching analysis was performed, and the delayed bleeding rate was compared between the groups. We analyzed 54,345 patients, of whom 8237 (15.16%) were in the no acid suppression group and 46,108 (84.84%) in the PPI or vonoprazan group (PPI: 34,380 and vonoprazan: 11,728). Delayed bleeding occurred in 1126 patients (2.07%). A total of 8237 pairs were created after matching. Delayed bleeding was not significantly different between the no acid suppression group and PPI or vonoprazan group, respectively (odds ratio: 1.20, 95% confidential interval: 0.93-1.54, P = 0.227). A sub-analysis according to the dose of PPI or vonoprazan, tumor location, and prescription of antithrombotic or anticoagulant medications was performed, but no significant effects of PPI or vonoprazan administration were found. PPI or vonoprazan did not prevent delayed bleeding; thus, the prescription of PPI and vonoprazan after esophageal ESD may not be recommended for the prevention of delayed bleeding.

Computer-aided diagnosis of early-stage colorectal cancer using nonmagnified endoscopic white-light images (with videos).

BACKGROUND AND AIMS: Differentiation of colorectal cancers (CRCs) with deep submucosal invasion (T1b) from CRCs with superficial invasion (T1a) or no invasion (Tis) is not straightforward. This study aimed to develop a computer-aided diagnosis (CADx) system to establish the diagnosis of early-stage cancers using nonmagnified endoscopic white-light images alone. METHODS: From 5108 images, 1513 lesions (Tis, 1074; T1a, 145; T1b, 294) were collected from 1470 patients at 10 academic hospitals and assigned to training and testing datasets (3:1). The ResNet-50 network was used as the backbone to extract features from images. Oversampling and focal loss were used to compensate class imbalance of the invasive stage. Diagnostic performance was assessed using the testing dataset including 403 CRCs with 1392 images. Two experts and 2 trainees read the identical testing dataset. RESULTS: At a 90% cutoff for the per-lesion score, CADx showed the highest specificity of 94.4% (95% confidence interval [CI], 91.3-96.6), with 59.8% (95% CI, 48.3-70.4) sensitivity and 87.3% (95% CI, 83.7-90.4) accuracy. The area under the characteristic curve was 85.1% (95% CI, 79.9-90.4) for CADx, 88.2% (95% CI, 83.7-92.8) for expert 1, 85.9% (95% CI, 80.9-90.9) for expert 2, 77.0% (95% CI, 71.5-82.4) for trainee 1 (vs CADx; P = .0076), and 66.2% (95% CI, 60.6-71.9) for trainee 2 (P < .0001). The function was also confirmed on 9 short videos. CONCLUSIONS: A CADx system developed with endoscopic white-light images showed excellent per-lesion specificity and accuracy for T1b lesion diagnosis, equivalent to experts and superior to trainees. (Clinical trial registration number: UMIN000037053.).

Palmitoylated CKAP4 regulates mitochondrial functions through an interaction with VDAC2 at ER-mitochondria contact sites.

Cytoskeleton-associated protein 4 (CKAP4) is a palmitoylated type II transmembrane protein localized to the endoplasmic reticulum (ER). Here, we found that knockout (KO) of CKAP4 in HeLaS3 cells induces the alteration of mitochondrial structures and increases the number of ER-mitochondria contact sites. To understand the involvement of CKAP4 in mitochondrial functions, the binding proteins of CKAP4 were explored, enabling identification of the mitochondrial porin voltage-dependent anion-selective channel protein 2 (VDAC2), which is localized to the outer mitochondrial membrane. Palmitoylation at Cys100 of CKAP4 was required for the binding between CKAP4 and VDAC2. In CKAP4 KO cells, the binding of inositol trisphosphate receptor (IP3R) and VDAC2 was enhanced, the intramitochondrial Ca2+ concentration increased and the mitochondrial membrane potential decreased. In addition, CKAP4 KO decreased the oxidative consumption rate, in vitro cancer cell proliferation under low-glucose conditions and in vivo xenograft tumor formation. The phenotypes were not rescued by expression of a palmitoylation-deficient CKAP4 mutant. These results suggest that CKAP4 plays a role in maintaining mitochondrial functions through the binding to VDAC2 at ER-mitochondria contact sites and that palmitoylation is required for this novel function of CKAP4.This article has an associated First Person interview with the first author of the paper.

Guidelines for endoscopic balloon dilation in treating Crohn's disease-associated small intestinal strictures (supplement to the Clinical Practice Guidelines for Enteroscopy).

Balloon-assisted enteroscopy allows endoscopic treatments in the deeper segments of the small bowel. Endoscopic balloon dilation has become a popular minimally invasive alternative for the treatment of Crohn's disease-associated small intestinal strictures. As a supplement to the Clinical Practice Guidelines for Enteroscopy, the Japan Gastroenterological Endoscopy Society's Working Committee has developed the present "Guidelines for endoscopic balloon dilation in treating Crohn's disease-associated small intestinal strictures," based on new scientific techniques and evidence. The guidelines cover standard procedures for the insertion route of the balloon endoscope, bowel preparation, indications, procedure-related complications, efficacy, target diameter and duration, management of multiple strictures, and the current state of combined and alternative treatments. Unresolved future research questions are also listed in this guideline.

Ratiometric Bioluminescent Indicator for a Simple and Rapid Measurement of Thrombin Activity Using a Smartphone.

Hemostasis is an essential function that repairs tissues and maintains the survival of living organisms. To prevent diseases caused by the abnormality of the blood coagulation mechanism, it is important to carry out a blood test periodically by a method that is convenient and less burdensome for examiners. Thrombin is a protease that catalyzes the conversion of fibrinogen, and its cleavage activity can be an index of coagulation activity. Here, we developed a ratiometric bioluminescent indicator, Thrombastor (thrombin activity sensing indicator), which reflects the thrombin cleavage activity in blood by changing the emission color from green to blue. Compared to the current thrombin activity indicator, the rapid color change of the emission indicated a 2.5-fold decrease in the Km for thrombin, and the cleavage rate was more than two times faster. By improving the absolute bioluminescence intensity, detection from a small amount of plasma could be achieved with a smartphone camera. Using Thrombastor and a versatile device, an effective diagnosis for preventing coagulation disorders can be provided.

Hyperspectral two-photon excitation microscopy using visible wavelength.

We demonstrate hyperspectral imaging by visible-wavelength two-photon excitation microscopy using line illumination and slit-confocal detection. A femtosecond pulsed laser light at 530 nm was used for the simultaneous excitation of fluorescent proteins with different emission wavelengths. The use of line illumination enabled efficient detection of hyperspectral images and achieved simultaneous detection of three fluorescence spectra in the observation of living HeLa cells with an exposure time of 1 ms per line, which is equivalent to about 2 µs per pixel in point scanning, with 160 data points per spectrum. On combining linear spectral unmixing techniques, localization of fluorescent probes in the cells was achieved. A theoretical investigation of the imaging property revealed high-depth discrimination property attained through the combination of nonlinear excitation and slit detection.

Automatic detection of various abnormalities in capsule endoscopy videos by a deep learning-based system: a multicenter study.

BACKGROUND AND AIMS: A deep convolutional neural network (CNN) system could be a high-level screening tool for capsule endoscopy (CE) reading but has not been established for targeting various abnormalities. We aimed to develop a CNN-based system and compare it with the existing QuickView mode in terms of their ability to detect various abnormalities. METHODS: We trained a CNN system using 66,028 CE images (44,684 images of abnormalities and 21,344 normal images). The detection rate of the CNN for various abnormalities was assessed per patient, using an independent test set of 379 consecutive small-bowel CE videos from 3 institutions. Mucosal breaks, angioectasia, protruding lesions, and blood content were present in 94, 29, 81, and 23 patients, respectively. The detection capability of the CNN was compared with that of QuickView mode. RESULTS: The CNN picked up 1,135,104 images (22.5%) from the 5,050,226 test images, and thus, the sampling rate of QuickView mode was set to 23% in this study. In total, the detection rate of the CNN for abnormalities per patient was significantly higher than that of QuickView mode (99% vs 89%, P < .001). The detection rates of the CNN for mucosal breaks, angioectasia, protruding lesions, and blood content were 100% (94 of 94), 97% (28 of 29), 99% (80 of 81), and 100% (23 of 23), respectively, and those of QuickView mode were 91%, 97%, 80%, and 96%, respectively. CONCLUSIONS: We developed and tested a CNN-based detection system for various abnormalities using multicenter CE videos. This system could serve as an alternative high-level screening tool to QuickView mode.

Genetically Encoded Photosensitizer for Destruction of Protein or Cell Function.

There are several paths when excited molecules return to the ground state. In the case of fluorescent molecules, the dominant path is fluorescence emission that is greatly contributing to bioimaging. Meanwhile, photosensitizers transfer electron or energy from chromophore to the surrounding molecules, including molecular oxygen. Generated reactive oxygen species has potency to attack other molecules by oxidation. In this chapter, we introduce the chromophore-assisted light inactivation (CALI) method using a photosensitizer to inactivate proteins in a spatiotemporal manner and development of CALI tools, which is useful for investigation of protein functions and dynamics, by inactivation of the target molecules. Moreover, photosensitizers with high efficiency make it possible optogenetic control of cell ablation in living organisms and photodynamic therapy. Further development of photosensitizers with different excitation wavelengths will contribute to the investigation of multiple proteins or cell functions through inactivation in the different positions and timings.

Hierarchical Development of Motile Polarity in Durotactic Cells Just Crossing an Elasticity Boundary.

Cellular durotaxis has been extensively studied in the field of mechanobiology. In principle, asymmetric mechanical field of a stiffness gradient generates motile polarity in a cell, which is a driving factor of durotaxis. However, the actual process by which the motile polarity in durotaxis develops is still unclear. In this study, to clarify the details of the kinetics of the development of durotactic polarity, we investigated the dynamics of both cell-shaping and the microscopic turnover of focal adhesions (FAs) for Venus-paxillin-expressing fibroblasts just crossing an elasticity boundary prepared on microelastically patterned gels. The Fourier mode analysis of cell-shaping based on a persistent random deformation model revealed that motile polarity at a cell-body scale was established within the first few hours after the leading edges of a moving cell passed through the boundary from the soft to the stiff regions. A fluorescence recovery after photobleaching (FRAP) analysis showed that the mobile fractions of paxillin at FAs in the anterior part of the cells exhibited an asymmetric increase within several tens of minutes after cells entered the stiff region. The results demonstrated that motile polarity in durotactic cells is established through the hierarchical step-wise development of different types of asymmetricity in the kinetics of FAs activity and cell-shaping with a several-hour time lag.Key words: Microelasticity patterned gel, durotaxis, cell polarity, focal adhesions, paxillin.

Automatic detection and classification of protruding lesions in wireless capsule endoscopy images based on a deep convolutional neural network.

BACKGROUND AND AIMS: Protruding lesions of the small bowel vary in wireless capsule endoscopy (WCE) images, and their automatic detection may be difficult. We aimed to develop and test a deep learning-based system to automatically detect protruding lesions of various types in WCE images. METHODS: We trained a deep convolutional neural network (CNN), using 30,584 WCE images of protruding lesions from 292 patients. We evaluated CNN performance by calculating the area under the receiver operating characteristic curve (AUC), sensitivity, and specificity, using an independent set of 17,507 test images from 93 patients, including 7507 images of protruding lesions from 73 patients. RESULTS: The developed CNN analyzed 17,507 images in 530.462 seconds. The AUC for detection of protruding lesions was 0.911 (95% confidence interval [Cl], 0.9069-0.9155). The sensitivity and specificity of the CNN were 90.7% (95% CI, 90.0%-91.4%) and 79.8% (95% CI, 79.0%-80.6%), respectively, at the optimal cut-off value of 0.317 for probability score. In a subgroup analysis of the category of protruding lesions, the sensitivities were 86.5%, 92.0%, 95.8%, 77.0%, and 94.4% for the detection of polyps, nodules, epithelial tumors, submucosal tumors, and venous structures, respectively. In individual patient analyses (n = 73), the detection rate of protruding lesions was 98.6%. CONCLUSION: We developed and tested a new computer-aided system based on a CNN to automatically detect various protruding lesions in WCE images. Patient-level analyses with larger cohorts and efforts to achieve better diagnostic performance are necessary in further studies.

The risks and characteristics of the delayed bleeding after endoscopic submucosal dissection for early gastric carcinoma in cases with anticoagulants.

BACKGROUND: Endoscopic submucosal dissection (ESD) is a minimally invasive treatment for early gastric carcinoma. Vitamin K antagonists and direct oral anticoagulants (DOAC) were reported to increase the risk of delayed bleeding after ESD. However, the evaluation of ESD cases taking anticoagulants is scarce. We analyzed the risk and characteristics of delayed bleeding after gastric ESD in patients on anticoagulants. METHODS: We performed a retrospective observational study at a single center. Consecutive patients who underwent ESD for early gastric carcinoma and took anticoagulants, including warfarin, rivaroxaban, dabigatran, apixaban, and edoxaban, between January 2012 and December 2018, were analyzed. We also calculated delayed bleeding rates for those without anticoagulants. RESULTS: Of 1855 eligible patients who underwent gastric ESDs, 143 took anticoagulants. Delayed bleeding occurred in 30 (21.0%) cases taking anticoagulants, with 15 (19.5%) cases in the DOAC group [rivaroxaban, seven cases (21.2%); dabigatran, four cases (20.0%); apixaban, four cases (23.5%); and edoxaban, zero cases (0%)] and 15 cases (22.7%) in the warfarin group. Furthermore, 43/344 (12.5%) patients taking antiplatelets and 76/1368 (5.6%) patients without antithrombic drugs experienced delayed bleeding. Multivariable logistic analysis revealed post-heart valve replacement (OR, 6.56; 95% CI, 1.75-24.7; p < .05) as a risk for delayed bleeding in warfarin-taking patients, while no statistically significant factor was found in DOAC-taking patients. CONCLUSIONS: Anticoagulants were associated with a high incidence of severe delayed bleeding. Careful attention should be paid to patients on anticoagulants after gastric ESD, especially those on warfarin after heart valve replacement.

Automatic detection of blood content in capsule endoscopy images based on a deep convolutional neural network.

BACKGROUND AND AIM: Detecting blood content in the gastrointestinal tract is one of the crucial applications of capsule endoscopy (CE). The suspected blood indicator (SBI) is a conventional tool used to automatically tag images depicting possible bleeding in the reading system. We aim to develop a deep learning-based system to detect blood content in images and compare its performance with that of the SBI. METHODS: We trained a deep convolutional neural network (CNN) system, using 27 847 CE images (6503 images depicting blood content from 29 patients and 21 344 images of normal mucosa from 12 patients). We assessed its performance by calculating the area under the receiver operating characteristic curve (ROC-AUC) and its sensitivity, specificity, and accuracy, using an independent test set of 10 208 small-bowel images (208 images depicting blood content and 10 000 images of normal mucosa). The performance of the CNN was compared with that of the SBI, in individual image analysis, using the same test set. RESULTS: The AUC for the detection of blood content was 0.9998. The sensitivity, specificity, and accuracy of the CNN were 96.63%, 99.96%, and 99.89%, respectively, at a cut-off value of 0.5 for the probability score, which were significantly higher than those of the SBI (76.92%, 99.82%, and 99.35%, respectively). The trained CNN required 250 s to evaluate 10 208 test images. CONCLUSIONS: We developed and tested the CNN-based detection system for blood content in CE images. This system has the potential to outperform the SBI system, and the patient-level analyses on larger studies are required.

Colon Capsule Endoscopy versus CT Colonography in Patients with Large Non-Polypoid Tumours: A Multicentre Prospective Comparative Study (4CN Study).

BACKGROUND/AIMS: Non-polypoid colon lesions compared with polypoid lesions has a high malignant potential. The diagnostic performance of colon capsule endoscopy (CCE) and CT colonography (CTC) for large colorectal non-polypoid tumours, that is, laterally spreading tumours is still unclear. The aim of this study is to evaluate the performance of CCE and CTC for the diagnosis of large non-polypoid tumours. METHODS: Thirty patients referred for endoscopic submucosal dissection of non-polypoid tumours measuring ≥20 mm were enrolled. Patients first underwent CCE, then colonoscopy (without resection) and CTC on the same day. An experienced gastroenterologist in a third hospital evaluated the CCE and recorded the location, size and morphology of all lesions detected, blinded to the colonoscopic findings. An experienced radiologist read the CTC under the same conditions. Colonoscopic findings were defined as the reference. RESULTS: A total of 30 lesions (T1 cancer: 3, Tis cancer: 7, adenoma: 14, sessile serrated adenoma/polyp: 6) in 27 patients were observed for evaluation. The capsule excretion rate within 8 h was 85% (23/27), and all capsules went beyond the target lesions. Non-polypoid tumours tend to be depicted as polypoid on CCE. Per patient sensitivities were 0.89 (24/27) by CCE and 0.70 (19/27) by CTC (p = 0.0253, McNemar), and per lesion sensitivities were 0.87 (26/30) and 0.67 (20/30) respectively (p = 0.0143). Most lesions missed by both modalities were located in the proximal colon. CONCLUSION: Eighty-seven per cent of non-polypoid tumours were detected by CCE, and the sensitivity using CCE was higher than that obtained using CTC (UMIN0000014772).

The sub-classification of type B2 vessels according to the magnifying endoscopic classification of the Japan Esophageal Society.

OBJECTIVES: Guidelines for magnified endoscopic diagnosis of esophageal squamous cell carcinoma (SCC) have been proposed by the Japan Esophageal Society. Type B1, B2, and B3 reflect increasing tumor invasion depths (within mucosal epithelium or into lamina propria mucosa [T1a-EP/LPM], into muscularis mucosa or superficial invasion into submucosa [T1a-MM/T1b-SM1], and into submucosa [T1b-SM2], respectively). The diagnostic accuracy of type B1 and B3 is high, but accuracy of type B2 is low. We aimed to improve the diagnostic accuracy of type B2. METHODS: We retrospectively reviewed 248 SCC lesions treated with endoscopic submucosal dissection between January 2012 and July 2018 and identified the B2 lesions. The maximum diameter of the area presenting B2 was measured and evaluated in relation to tumor invasion, for which receiver-operating characteristic (ROC) curves were generated. The optimal area size for distinguishing T1a-EP/LPM from T1a-MM or deeper invasion was determined. RESULTS: There were 78 lesions with B2, of which 26 (33%) were T1a-MM or T1b-SM1 SCCs. ROC curve analysis indicated that the optimal cut-off for the target area showing B2 was 4 mm. The invasion depth (EP/LPM: MM/SM1: SM2) of B2 observed in an area with a diameter <4 mm (B2-Narrow) and those with diameter ≥4 mm (B2-Broad) was 46:11:1 and 1:15:4, respectively. To predict T1a-MM or deeper invasion, B2-Broad had a sensitivity, specificity, positive predictive value, and negative predictive value of 61%, 98%, 95%, and 79%, respectively. CONCLUSION: The diagnostic accuracy of type B2 was improved by evaluating the area of type B2.

Artificial intelligence using a convolutional neural network for automatic detection of small-bowel angioectasia in capsule endoscopy images.

BACKGROUND AND AIM: Although small-bowel angioectasia is reported as the most common cause of bleeding in patients and frequently diagnosed by capsule endoscopy (CE) in patients with obscure gastrointestinal bleeding, a computer-aided detection method has not been established. We developed an artificial intelligence system with deep learning that can automatically detect small-bowel angioectasia in CE images. METHODS: We trained a deep convolutional neural network (CNN) system based on Single Shot Multibox Detector using 2237 CE images of angioectasia. We assessed its diagnostic accuracy by calculating the area under the receiver operating characteristic curve (ROC-AUC), sensitivity, specificity, positive predictive value, and negative predictive value using an independent test set of 10 488 small-bowel images, including 488 images of small-bowel angioectasia. RESULTS: The AUC to detect angioectasia was 0.998. Sensitivity, specificity, positive predictive value, and negative predictive value of CNN were 98.8%, 98.4%, 75.4%, and 99.9%, respectively, at a cut-off value of 0.36 for the probability score. CONCLUSIONS: We developed and validated a new system based on CNN to automatically detect angioectasia in CE images. This may be well applicable to daily clinical practice to reduce the burden of physicians as well as to reduce oversight.

Clinical usefulness of a deep learning-based system as the first screening on small-bowel capsule endoscopy reading.

BACKGROUND AND AIM: To examine whether our convolutional neural network (CNN) system based on deep learning can reduce the reading time of endoscopists without oversight of abnormalities in the capsule-endoscopy reading process. METHODS: Twenty videos of the entire small-bowel capsule endoscopy procedure were prepared, each of which included 0-5 lesions of small-bowel mucosal breaks (erosions or ulcerations). At another institute, two reading processes were compared: (A) endoscopist-alone readings and (B) endoscopist readings after the first screening by the proposed CNN. In process B, endoscopists read only images detected by CNN. Two experts and four trainees independently read 20 videos each (10 for process A and 10 for process B). Outcomes were reading time and detection rate of mucosal breaks by endoscopists. Gold standard was findings at the original institute by two experts. RESULTS: Mean reading time of small-bowel sections by endoscopists was significantly shorter during process B (expert, 3.1 min; trainee, 5.2 min) compared to process A (expert, 12.2 min; trainee, 20.7 min) (P < 0.001). For 37 mucosal breaks, detection rate by endoscopists did not significantly decrease in process B (expert, 87%; trainee, 55%) compared to process A (expert, 84%; trainee, 47%). Experts detected all eight large lesions (>5 mm), but trainees could not, even when supported by the CNN. CONCLUSIONS: Our CNN-based system for capsule endoscopy videos reduced the reading time of endoscopists without decreasing the detection rate of mucosal breaks. However, the reading level of endoscopists should be considered when using the system.

Smartphone-Based Portable Bioluminescence Imaging System Enabling Observation at Various Scales from Whole Mouse Body to Organelle.

Current smartphones equipped with high-sensitivity and high-resolution sensors in the camera can respond to the needs of low-light imaging, streaming acquisition, targets of various scales, etc. Therefore, a smartphone has great potential as an imaging device even in the scientific field and has already been introduced into biomolecular imaging using fluorescence tags. However, owing to the necessity of an excitation light source, fluorescence methods impair its mobility. Bioluminescence does not require illumination; therefore, imaging with a smartphone camera is compact and requires minimal devices, thus making it suitable for personal and portable imaging devices. Here, we report smartphone-based methods to observe biological targets in various scales using bioluminescence. In particular, we demonstrate, for the first time, that bioluminescence can be observed in an organelle in a single living cell using a smartphone camera by attaching a detachable objective lens. Through capturing color changes with the camera, changes in the amount of target molecules was detected using bioluminescent indicators. The combination of bioluminescence and a mobile phone makes possible a compact imaging system without an external light source and expands the potential of portable devices.