Long-term Outcome of Asymptomatic Esophageal Eosinophilia

Background/Aims

: Asymptomatic esophageal eosinophilia (aEE), characterized by eosinophil infiltration in the esophagus without clinical symptoms, has been reported as a precursor of eosinophilic esophagitis (EoE). Nevertheless, no report exists on the long-term clinical course of the disease. Therefore, this study aimed to investigate the long-term clinical course of aEE over 5 years, including the symptomatic conversion rate and the effect of treatments.

Methods

: We reviewed 28 patients with aEE who had been followed up for over 5 years with endoscopic monitoring. The basal characteristics of patients were compared with those of 58 patients diagnosed with EoE during the same period. Patients' clinicopathological findings were collected and examined.

Results

: No significant differences in basal characteristics and histopathological findings were observed between the patients with aEE and those with EoE. The median follow-up duration was 64 months. Among the 28 patients with aEE, seven were treated with proton pump inhibitor or potassium-competitive acid blocker and the remaining 21 opted for follow-up with no medication. Among the treated patients, six (85.7%) exhibited endoscopic and pathologic improvements. Among the cases followed up without medication, the findings worsened in two (9.5%), improved spontaneously in seven (33.3%), and were unchanged in 12 (57.1%), and three (14.3%) developed symptoms at a mean time of 40 months. Symptoms developed in cases where endoscopic and pathologic findings remained unchanged or worsened during follow-up.

Conclusions

: Some patients with aEE had improved findings without treatment, whereas others developed symptoms, emphasizing the importance of long-term monitoring and individualized treatment decisions.

Long-term endoscopic change of gastric polyp associated with administration of vonoprazan

Vonoprazan (VPZ) has been available in Japan since 2015. Endoscopic features of proton-pump inhibitor (PPI)-related gastric mucosal changes, including fundic gland and hyperplastic polyps, have been observed. However, the relationship between gastric polyps and VPZ remains unclear. A 65-year-old man with reflux esophagitis-associated symptoms refractory to PPI was referred to our hospital. VPZ (20 mg) was administered for 3 weeks, which proved effective. Afterward, VPZ dose was reduced to 10 mg; the reflux symptoms worsened, and 20 mg VPZ was restarted. Afterward, esophagogastroduodenoscopy (EGD) revealed a gradually enlarging gastric polyp in the cardia. After 5 years of VPZ administration, the patient developed a reddish polyp (approximately 10 mm) with a whitish substance in the cardia. Based on the clinical course, the polyp was considered to have enlarged because of the long-term VPZ administration. After being informed of the endoscopic findings, the patient decided to discontinue VPZ. One year after VPZ discontinuation, EGD revealed a shrunken polyp (5 mm). Long-term acid suppression causes hypergastrinemia, which may lead to gastric mucosal changes, including gastric polyps. There are few case reports of a decrease in the number and size of gastric polyps after VPZ discontinuation. Hence, some VPZ-induced endoscopic changes may be reversible.

Symptomatic epiphrenic diverticulum in an older patient successfully treated nonsurgically

Epiphrenic diverticulum is a rare condition commonly diagnosed in middle-aged adults. Symptoms include dysphagia and regurgitation, which are associated with underlying esophageal motility disorders. We herein report a 93-year-old woman with dysphagia diagnosed with symptomatic epiphrenic diverticulum by computed tomography, esophagogastroduodenoscopy, and esophagography. The patient was successfully treated non-surgically without any complications. This case demonstrates that conservative treatment is an option for older high-risk patients.

Mucosal and Submucosal Thickening of Esophageal Wall Is a Promising Factor in the Development of Symptoms in Eosinophilic Esophagitis

Background/Aims

Asymptomatic esophageal eosinophilia (aEE) is considered to be a potential precursor of eosinophilic esophagitis (EoE). However, there are few clinical parameters that can be used to evaluate the disease. Therefore, we aimed to clarify the factors involved in the symptoms of EoE by examining the clinicopathological differences between aEE and EoE.

Methods

We reviewed 41 patients with esophageal eosinophilia who underwent endoscopic ultrasonography and high-resolution manometry. They were divided into the aEE group (n=16) and the EoE group (n=25) using the Frequency Scale for the Symptoms of Gastroesophageal Reflux Disease score. The patients' clinicopathological findings were collected and examined.

Results

The median Frequency Scale for the Symptoms of Gastroesophageal Reflux Disease score was 3.0 in the aEE group and 10.0 in the EoE group. There was no significant difference in patient characteristics, endoscopic findings and pathological findings. The cutoff value for wall thickening was 3.13 mm for the total esophageal wall thickness and 2.30 mm for the thickness from the surface to the muscular layer (total esophageal wall thickness: 84.0% sensitivity, 75.0% specificity; thickness from the surface to the muscular layer: 84.0% sensitivity, 68.7% specificity). The high-resolution manometry study was abnormal in seven patients (43.8%) in the aEE group and in 12 (48.0%) in the EoE group. The contractile front velocity was slower in the EoE group (p=0.026).

Conclusions

The esophageal wall thickening in the lower portion of the esophagus is an important clinical factors related to the symptoms in patients with EoE.

Helicobacter fennelliae Localization to Diffuse Areas of Human Intestine, Japan

The site of enterohepatic Helicobacter colonization/infection in humans is still unknown. We report microbiologically and histopathologically confirmed H. fennelliae localization in the large intestine in an immunocompromised patient in Japan. This case contributes to better understanding of the life cycle of enterohepatic Helicobacter species.

Validity of Endoscopic Submucosal Dissection for Gastric Cancer Diagnosed as Differentiated Adenocarcinoma Before Treatment Regardless of Lesion Size

BACKGROUND/AIMS

We investigated the validity and safety of endoscopic submucosal dissection for gastric tumors by examining shortand long-term outcomes by tumor diameter.

MATERIALS AND METHODS

Endoscopic submucosal dissection for gastric tumor was performed on 4259 lesions at our hospital between January 2005 and June 2021. [Study 1] Patients were divided into 5 tumor diameter groups: 3751 lesions, ≤30 mm; 366 lesions, 31-50 mm; 106 lesions, 51-75 mm; 24 lesions, 76-100 mm; and 12 lesions, ≥101 mm. Short-term gastric endoscopic submucosal dissection outcomes were investigated. [Study 2] Long-term outcomes (delayed gastric emptying and prognosis) were investigated in 508 cases with tumor diameter ≥31 mm.

RESULTS

[Study 1] Perforation rate (%) was 1.2, 3.6, 3.8, 12.5, and 25.0 for lesions with tumor diameter ≤30 mm, in the range 31-50 mm, 51-75 mm, and 76-100 mm, and ≥101 mm, respectively. Postoperative bleeding rate (%) was 4.8, 9.0, 6.6, 20.8, and 33.3, respectively, R0 resection rate (%) was 96.8, 90.2, 89.6, 70.8, and 66.6, respectively, and curative resection rate (%) was 92.0, 61.2, 63.2, 45.8, and 8.3, respectively. [Study 2] There were 7 cases of delayed gastric emptying after wide resection, with 3 patients requiring balloon dilatation, 1 of whom subsequently underwent distal gastrectomy. Among 205 cases of noncurative resection, 110 underwent additional surgery, residual cancer was present in 11 cases, and lymph node metastasis was observed in 7 cases (1 patient died of disease). To date, 1 of the 95 patients being followed up has died of disease (mean follow-up: 2042 days).

CONCLUSION

Even with a tumor diameter ≥31 mm, curative resection was achieved in about 60% of cases in which intramucosal lesions were considered possible preoperatively, but the rate was low at 8.3% for tumor diameter ≥101 mm. Long-term outcomes appear favorable, with only 0.4% of the patients dying of disease but delayed gastric emptying observed in 1.7% of cases.

Diagnostic Performance of Endoscopic Ultrasonography with Water-Filled Balloon Method for Superficial Esophageal Squamous Cell Carcinoma

BACKGROUND

Endoscopic ultrasonography (EUS) is a commonly used tool for preoperative depth diagnosis of superficial esophageal squamous cell carcinoma (ESCC). Probing EUS using the water-filled balloon method is a simple and safe examination.

AIM

The aim of this study was to clarify the diagnostic performance of EUS with the water-filled balloon method for superficial ESCC compared to magnifying narrow-band imaging (ME-NBI).

METHODS

We retrospectively examined 403 lesions in 393 consecutive patients diagnosed with ESCC and evaluated them with ME-NBI and EUS. Clinicopathological findings were collected, and the accuracy of the preoperative diagnosis was compared between ME-NBI and EUS-B. EUS examiners were not blinded to prior ME-NBI results, and EUS results may have been influenced by ME-NBI results.

RESULTS

The pathological tumor depth of the EP/LPM in 152 lesions, MM/SM1 in 130 lesions, and deep submucosa (SM2/SM3) in 121 lesions was examined. The proportion of total lesions with an accurate diagnosis was significantly higher in EUS than in ME-NBI (67.7% versus 62.0%, P = 0.015). When analyzed by clinical depth diagnosis using ME-NBI, the proportion of lesions with an accurate diagnosis was significantly higher for EUS in MM/SM1 (55.7% versus 46.1%, P = 0.033). The sensitivity was significantly higher in EUS for SM2/SM3 lesions (76.0% versus 54.5%, P < 0.001). The accuracy and specificity of EUS, which differentiate MM/SM1 from EP/LPM or SM2/SM3, were significantly higher than those of ME-NBI. The median endoscopic ultrasonography procedure time was approximately 6.5 min.

CONCLUSIONS

EUS with the water-filled balloon method is a safe and straightforward method that can be performed on lesions clinically diagnosed as MM/SM1 using ME-NBI. We retrospectively reviewed lesions in patients diagnosed with ESCC and evaluated them using magnifying endoscopy with narrow-band imaging (ME-NBI) and endoscopic ultrasound using the water-filled balloon method (EUS-B). We conclude that EUS-B can increase the diagnostic accuracy.

Long-term outcome of cervical lymph node metastasis in superficial pharyngeal squamous cell carcinoma after endoscopic submucosal dissection

BACKGROUND AND AIMS

Superficial pharyngeal squamous cell carcinoma (PSCC) has received increasing attention as a therapeutic target in the GI field with recent innovations in endoscopic submucosal dissection (ESD). However, there are currently no defined criteria for the application of ESD to superficial PSCC. One of the problems encountered during follow-up after ESD is cervical lymph node metastasis (LNM). Identifying the clinicopathologic predictors of cervical LNM can help to provide a basis for the refinement of therapeutic strategies for superficial PSCC.

METHODS

The risk of cervical LNM was evaluated in 331 patients with superficial PSCC who underwent initial ESD between 2008 and 2021. Since tumor size, rather than depth, is the dominant factor in the current TNM classification for PSCC, the correlation between tumor size and thickness was investigated.

RESULTS

The median follow-up period was 4.8 years. The cumulative 5-year cervical LNM rate was 6.1%. Multivariate Cox proportional hazards regression analysis identified tumor thickness ≥1000 μm and lymphatic invasion as significant independent predictors. Among 204 cases with subepithelial invasion, both factors were also revealed to be significant independent predictors, suggesting that tumor thickness was superior to tumor size in predicting cervical LNM. Despite the positive correlation between tumor thickness and size, there was noticeable variability in the values (R = .20), and the current staging was inadequate to identify groups at high risk for cervical LNM.

CONCLUSIONS

Tumor thickness and lymphatic invasion are validated as significant independent predictors for cervical LNM and can be useful indicators to optimize the therapeutic strategies for superficial PSCC.

Advanced Appendiceal Cancer with Systematic Metastasis without Gastrointestinal Symptoms Found by Subcutaneous Tumor

An 86-year-old woman with a subcutaneous nodule in her left axilla visited our hospital. She had no gastrointestinal symptoms, but contrast-enhanced computed tomography revealed a cecal mass and systemic metastasis, including cutaneous, bone, peritoneal dissemination and ascites. Colonoscopy revealed a circumferential, elevated cecal lesion. She underwent right hemicolectomy to prevent colon obstruction. The pathological diagnosis was poorly differentiated adenocarcinoma (por1>tub2>muc) arising from the appendix with a BRAFV600E mutation and microsatellite instability-high. Chemotherapy was administered, and she is currently still alive and undergoing chemotherapy. We describe a rare case of advanced appendiceal cancer without gastrointestinal symptoms diagnosed due to cutaneous metastasis.

Metachronous Multiple Gastric Cancer Discovered as Endoscopic Curability C2 during Regular Follow-Up after Gastric Endoscopic Submucosal Dissection

INTRODUCTION

The objective of this study was to clarify characteristics of metachronous endoscopic curability C2 (eCura C2) cancer during post-endoscopic submucosal dissection (ESD) follow-up.

METHODS

Of 4,355 gastric lesions treated by ESD at our hospital during 2005-2021, 657 were metachronous. After excluding lesions found ≥2 years since the prior examination or in the gastric remnant, the remaining 515 were analyzed. Study 1: We compared 35 eCura C2 cancers and 480 eCura A-C1 cancers. Study 2: Endoscopic findings of the 35 lesions were examined to determine why they had been missed.

RESULTS

Mean tumor size was larger (34.0 mm vs. 12.1 mm, p < 0.01) and the proportions of mixed-type and poorly differentiated cancers were higher (highly:mixed:poorly, 34.3:57.1:8.6 vs. 94.2:5.0:0.8, p < 0.01) in the eCura C2 group. Study 2: At the prior examination, 4 lesions were noticed but considered benign, 2 lacked sufficient imaging, 19 were detectable on imaging but missed, and 10 were not detectable on imaging. Over half the lesions that were detectable but missed at the prior examination were in the lesser curvature, many being type IIa-IIb lesions with color similar to the background mucosa. All lesions not detectable on imaging at the prior examination were mixed-type or poorly differentiated type.

DISCUSSION

Metachronous cancer detected as eCura C2 cancers was significantly larger, and a significantly higher proportion was mixed-type or poorly differentiated cancers, compared with eCura A-C1 cancers. Possible reasons why these lesions were missed include rapid progression of mixed-type and poorly differentiated cancers, and poor recognition that lesions showing only slight color changes may be present at the lesser curvature.

Safety of Cold Snare Polypectomy during Continuous Use of Antithrombotic Drugs for Delayed Post-Polypectomy Bleeding: A Pilot Study

BACKGROUND

Cold snare polypectomy is a high-risk endoscopic procedure with a low delayed post-polypectomy bleeding rate. However, it is unclear whether delayed post-polypectomy bleeding rates increase during continuous antithrombotic treatment. This study aimed to determine the safety of cold snare polypectomy during continuous antithrombotic treatment.

METHODS

This single-center, retrospective cohort study enrolled patients who underwent cold snare polypectomy during antithrombotic treatment between January 2015 and December 2021. Patients were divided into continuation and withdrawal groups based on whether they continued with antithrombotic drugs or not. Propensity score matching was performed using age, sex, Charlson comorbidity index, hospitalization, scheduled treatment, type of antithrombotic drugs used, multiple medications used, indication for antithrombotic drugs, and gastrointestinal endoscopist qualifications. The delayed polypectomy bleeding rates were compared between the groups. Delayed polypectomy bleeding was defined as the presence of blood in stools and requiring endoscopic treatment or a decrease in hemoglobin level by 2 g/dL or more.

RESULTS

The continuation and withdrawal groups included 134 and 294 patients, respectively. Delayed polypectomy bleeding was observed in 2 patients (1.5%) and 1 patient (0.3%) in the continuation and withdrawal groups, respectively (p = 0.23), before propensity score matching, with no significant difference. After propensity score matching, delayed polypectomy bleeding was observed in 1 patient (0.9%) in the continuation group but not in the withdrawal group, with no significant difference.

CONCLUSION

Cold snare polypectomy during continuous antithrombotic treatment did not significantly increase delayed post-polypectomy bleeding rates. Therefore, this procedure may be safe during continuous antithrombotic treatment.

A new device for endoscopic band ligation for colorectal diverticular bleeding

Background and study aims  Endoscopic band ligation (EBL) has been reported to be effective for colorectal diverticular bleeding. However, current EBL devices have some limitations, and we have developed a novel EBL device. Methods  This novel EBL device has a tapered hood attached to the tip of the endoscope and an outer cylinder that loads two EBL bands. Twelve EBL procedures were performed in a live porcine model alternately using a conventional EBL device (Group C) and the novel EBL device (Group N). Results  EBL was successful in all cases in both groups. There were no cases of perforation in the 10 days after EBL. After ligation, the mean major axis of the ridge was significantly larger in Group N than Group C (9.7 ± 1.4 mm vs 7.2 ± 1.4 mm, P  = 0.011). Pathological examination revealed disruption of the muscularis propria at four of the six ligation sites in Group C and at five of the six ligation sites in Group N. Conclusions  Using this novel EBL device, it was possible to perform multiple ligation procedures in succession with a good field of view. No perforation was observed, but disruption of the muscularis propria was observed at approximately three-quarters of the ligation sites pathologically.

Feasibility of Rescue Colonoscopy Using a Short-type Enteroscope (SIF-H290S) without Overtube after Incomplete Colonoscopy: A Single-center Retrospective Pilot Study

Objectives:

Recently, a newly designed short-type single-balloon enteroscope (SBE), SIF-H290S, has been developed with a smaller outer diameter and a longer working length than conventional colonoscopes. It has passive bending and high-force transmission, making insertion easier. However, it is difficult to perform rescue colonoscopy with an SBE after incomplete colonoscopy in the same session. Therefore, this study evaluated the feasibility of consecutive rescue colonoscopy using SIF-H290S without overtube after incomplete colonoscopy.

Methods:

This was a single-center retrospective study. We included 19 rescue colonoscopies (19 patients) with SIF-H290S without overtube performed by 11 endoscopists in the SIF group and 38 rescue colonoscopies (38 patients) using a small-caliber colonoscope (PCF-PQ260L) were randomly selected for the control group from procedures performed by the same 11 endoscopists. We compared the cecal intubation rate and other outcomes, such as insertion time, between the two groups.

Results:

The median age of the patients was 72 and 69 years, with 8 and 26 males in the SIF and control groups, respectively. The median body mass index was 21.6 and 22.7 kg/m² in the SIF and control groups, respectively. There were no significant differences in the patient backgrounds between the groups, except for the reason for incomplete colonoscopy (p = 0.048). The cecal intubation rate was 78.9% (15/19 procedures) and 92.1% (35/38 procedures) in the SIF and control groups, respectively.

Conclusions:

This study revealed the real-world experience and feasibility of rescue colonoscopy using SIF-H290S, which could be a potential rescue device option after incomplete colonoscopy.

Shielding device for endoscopic procedures during lower gastrointestinal endoscopy

Objectives

The coronavirus pandemic significantly impacted endoscopic practice. During lower gastrointestinal endoscopy, infectious substances disseminate; therefore, we developed an infection control device (STEP‐L) for lower gastrointestinal endoscopy and examined its usefulness.

Methods

STEP‐L wraps around the patient's buttocks and covers the endoscope. Using lower endoscopy training models, three endoscopists performed 18 colonoscopies with STEP‐L (group S) and without (group C). Endoscopic insertion time and pigmented areas of ​​gloves and diapers after the examination were compared between both groups.

Results

Insertion of the endoscope up to the cecum was possible in all 18 examinations. The insertion time to the cecum was 52.4 ± 19.0 s in group S and 53.9 ± 13.3 s in group C. The pigmented areas of the ​​gloves measured 39,108.0 ± 16,155.3 pixels in group C, but were significantly reduced to 2610.5 ± 4333.8 pixels in group S (p < 0.05). The pigmented areas of the diapers measured 2280.9 ± 3285.2 pixels in group C, but were significantly reduced to 138.0 ± 82.9 pixels in group S (p < 0.05).

Conclusions

Using STEP‐L does not change the insertion time, and is technically feasible. STEP‐L significantly reduces the adhesion of virtual pollutants to the surroundings, suggesting that this device is useful for infection control during lower gastrointestinal endoscopy.

Comprehensive risk evaluation for metachronous carcinogenesis after endoscopic submucosal dissection of superficial pharyngeal squamous cell carcinoma

BACKGROUND

Pharyngeal squamous cell carcinoma (PSCC) is associated with a high likelihood of metachronous carcinogenesis, which is known to have a poor prognosis. This study aimed to identify comprehensive risk evaluation indicators for metachronous carcinogenesis after endoscopic submucosal dissection (ESD) of superficial PSCC.

METHODS

The risk of metachronous carcinogenesis was evaluated in 144 patients with superficial PSCC (with no history of PSCC or esophageal squamous cell carcinoma) who underwent initial ESD from 2008 to 2020. Multiple lugol-voiding lesions (LVLs) in the background pharyngeal and esophageal epithelium were evaluated as endoscopic indicators. The hemoglobin, albumin, lymphocyte, and platelet (HALP) score was analyzed as a serum marker.

RESULTS

The median follow-up period was 4.3 years. The coincidence rate for pharyngeal and esophageal LVL grade was 55%. The cumulative 3-year metachronous PSCC rate was 18.9%. The cumulative 3-year second metachronous PSCC rate was 43.9%. Forward stepwise multivariate Cox proportional hazards regression analysis identified pharyngeal LVL grade and a lower HALP score as significant independent predictors. Pharyngeal LVL grade was superior to esophageal LVL grade as a predictor of metachronous PSCC. A lower HALP score was significantly associated with younger age in forward stepwise multivariate logistic regression analysis.

CONCLUSIONS

Patients with a history of superficial PSCC remain at risk for metachronous carcinogenesis over time, and long-term follow-up is imperative. Comprehensive evaluation of endoscopic features with a novel serum marker, namely, the HALP score, can help predict metachronous carcinogenesis.

Clinicopathological Differences between Eosinophilic Esophagitis and Asymptomatic Esophageal Eosinophilia

Objective According to consensus guidelines, eosinophilic esophagitis (EoE) is defined as a clinicopathological entity whose symptoms and histology must always be considered together. However, endoscopic findings typical of EoE are often seen in asymptomatic esophageal eosinophilia (aEE). We aimed to clarify the clinicopathological features of aEE. Methods We retrospectively compared cases of aEE and those of symptomatic EoE. Materials We reviewed 146 patients who underwent upper gastrointestinal endoscopy and were confirmed histopathologically to have esophageal eosinophil infiltration of at least 15 eosinophils per high-power field. They were divided into the aEE group (n=75) and the EoE group (n=71). Patients' clinicopathological findings were then collected and examined. Results The EoE group experienced dysphagia (47.9%), heartburn (40.8%), food impaction (40.8%), chest pain (16.9%), and other symptoms (8.5%). There was no significant difference between the two groups with regard to age, sex, current smoking status, or alcohol consumption. The aEE group had a significantly higher body mass index (p<0.01) and significantly lower frequency of concurrent allergic diseases (p<0.01) than the EoE group. No significant differences were found between the two groups with regard to the mean peripheral blood eosinophil count, non-specific immunoglobulin E concentration, peak eosinophil infiltration in the biopsy specimens, EoE histology scoring system, phenotype and location of typical endoscopic findings of EoE, or thickness of the esophagus wall or the mucosal and submucosal layer as measured by endoscopic ultrasonography. Two patients in the aEE group who were followed up without treatment subsequently developed esophageal symptoms. Conclusion aEE and EoE may have the same clinicopathological features.

Pepsinogen I- and H+/K+-ATPase-immunohistochemical Positivity in Endoscopically Resected Early Gastric Neoplasia

Gastric adenocarcinoma of the fundic gland type (GAFG) has been recently classified by the World Health Organization (WHO), however, clinicopathologic features of pepsinogen I- or H+/K+-ATPase-positive gastric tumors remain unclear. Therefore, this study evaluates the frequency and clinicopathologic features of those tumors, using a tissue microarray block to identify pepsinogen I- or H+/K+-ATPase-positive tumors from 810 endoscopically resected, early gastric epithelial tumors. The frequency of pepsinogen I-positive lesions was 2.1%, and that of H+/K+-ATPase-positive lesions was 2.0%. Pepsinogen I- or H+/K+-ATPase positivity was not observed in undifferentiated-type tumors, while gastric tumors with morphologic similarity to fundic glands were positive for pepsinogen I- or H+/K+-ATPase. We divided pepsinogen I- or H+/K+-ATPase-positive gastric tumors into group A, with fundic gland-like structure, or group B, without fundic gland-like structure. The frequency of group A was 1.6%: 46.2% were positive only for pepsinogen I and 53.8% for H+/K+-ATPase and pepsinogen I. The frequency of group B was 1.5%: 25% were positive only for pepsinogen I, 8.3% for H+/K+-ATPase and pepsinogen I, and 66.7% only for H+/K+-ATPase. The 2 tumor groups differed in location and endoscopic features. Hematoxylin and eosin staining showed that group B had more exposed tumors to the surface, larger nuclei, and more background atrophy than group A. Immunostaining showed significantly higher positivity rates for MUC5AC, CD10, CDX2, and p53 expression, and a higher Ki-67 labeling score. Our results provide novel insights into the pathology of early gastric tumors with histologic or immunohistochemical evidence of fundic gland differentiation.

Effect of Helicobacter pylori infection on malignancy of undifferentiated-type gastric cancer

BACKGROUND

Although almost all cases of gastric cancer are caused by Helicobacter pylori (HP) infection, there are some rare exceptions. Furthermore, the clinicopathological characteristics of gastric cancer may differ depending on HP infection status. This study aimed to determine the clinicopathological characteristics of undifferentiated-type gastric cancer (UD-GC) according to HP status.

METHODS

The study involved 83 patients with UD-GC who were selected from 1559 patients with gastric cancer who underwent endoscopic resection at our hospital and whose HP infection status was confirmed. Clinicopathological characteristics were evaluated according to HP status (eradicated, n = 28; infected, n = 32; not infected, n = 23).

RESULTS

In patients without HP infection, UD-GCs were < 20 mm and intramucosal with no vascular invasion. In patients with eradicated HP, there was no correlation between development of UD-GC and time since eradication. Nine of twelve patients with a tumor detected ≥ 5 years after eradication had undergone yearly endoscopy. Submucosal invasion was observed in two of four patients and lymphovascular invasion in three of four patients whose UD-GC was detected ≥ 10 years after eradication. There was no significant between-group difference in the frequency of lesions with invasion into the submucosal layer or deeper (14.3%, 10.5%, and 0% in the UD-E, UD-I, and UD-U groups, respectively).

CONCLUSION

The clinicopathological characteristics of UD-GC were similar between HP-infected patients and HP-eradicated patients. Three of four patients with eradicated HP whose UD-GC developed ≥ 10 years after eradication were not eligible for endoscopic treatment and required additional surgery resection. In contrast, UD-GC was curable by endoscopic resection in all patients without HP infection.

Effectiveness of Clipping for Definitive Colonic Diverticular Bleeding in Preventing Early Recurrent Bleeding

Objective Clipping is a common technique for managing colonic diverticular bleeding (CDB), despite the lack of published evidence regarding its effectiveness. We aimed to evaluate the effectiveness of clipping for CDB in preventing early recurrent bleeding. Methods This dual-center retrospective study included 93 patients who underwent emergency hospitalization for bloody stool, diagnosed with definitive CDB, and treated with clipping or conservative treatment. The primary outcome was early recurrent bleeding. A logistic regression analysis was performed to assess the association between the occurrence of early recurrent bleeding and clipping with adjustment for propensity scores. Secondary outcomes included death, transfusion, length of hospitalization, need for transcatheter arterial embolization or surgery, and adverse events. Results The patient characteristics were similar between the clipping (n=85) and conservative treatment (n=8) groups. The rate of early recurrent bleeding was significantly lower in the clipping group than in the conservative treatment group [23.5% (20 cases) vs. 75% (6 cases), p=0.005]. In the propensity score-adjusted logistic regression analysis, the odds ratio for early recurrent bleeding in the clipping group was 0.094 (95% confidence interval, 0.008-0.633, p=0.026). Secondary outcomes were not significantly different between the two groups. Stigmata of recent hemorrhage (SRH) at the time of recurrent bleeding was identified in 79.2% of patients (19/24). In the clipping group, recurrent bleeding was observed in 62.5% of cases (10/16) from the same diverticulum. However, early recurrent bleeding tended to be less likely with direct clipping (p=0.072). Conclusion Clipping for definite CDB was more effective in preventing early recurrent bleeding than conservative treatment.

Endoscopic Submucosal Dissection Improves Bloody Stool Associated with Polypoid Type Mucosal Prolapse Syndrome: A Case Series

Mucosal prolapse syndrome (MPS) is a benign inflammatory disease of the rectum that causes bloody stool. Endoscopic treatment for MPS has not been established. We herein report a consecutive case series of endoscopic submucosal dissection (ESD) for MPS. There were four cases treated with ESD alone. All lesions were on the dentate line, and all were polypoid. The median procedure time was 77 minutes. No complications were observed. The median observation period was 1,108 days, and bloody stool and endoscopic recurrence of MPS were not observed.ESD for polypoid-type MPS was an effective treatment for improving bloody stool and suppressing endoscopic recurrence.

Efficacy of Vonoprazan for Refractory Reflux Esophagitis after Esophagectomy

BACKGROUND

Refractory reflux esophagitis (RRE), unresponsive to conventional proton-pump inhibitors (PPIs), is a complication in esophagectomy with gastric pull-up. Vonoprazan (VPZ), a novel potassium-competitive acid blocker, has been available in Japan since 2015. Here, we investigated the efficacy of VPZ on PPI-resistant RRE after esophagectomy with gastric pull-up.

METHODS

This was a single-center retrospective study. We used the revised Los Angeles (r-LA) classification based on the Los Angeles classification and the modified Los Angeles classification to evaluate abnormal forms of mucosal breaks such as lateral spreading consistently. Patients who underwent esophagectomy with gastric pull-up and had RRE grade B-D as per the r-LA classification, despite using standard-dose PPIs or double dose of rabeprazole, were included. Sixteen patients who switched to VPZ (20 mg/day) and 14 patients who continued PPIs were assigned to the VPZ and PPI groups, respectively. Endoscopic observations were reviewed by 3 endoscopists using the r-LA classification to ensure consistent diagnosis, while the treatment arm and patient information were blinded to evaluators. We defined mucosal breaks that improved by at least one grade after treatment as improved mucosa and recovery to grade M or N as mucosal healing.

RESULTS

The percentage of patients with improved mucosa in the VPZ and PPI groups was 81.3 and 14.3%, respectively (p < 0.001). The rate of mucosal healing was 68.8 and 7.1%, respectively (p = 0.001).

CONCLUSION

VPZ significantly improved PPI-resistant RRE after esophagectomy with gastric pull-up.

Possibility of new shielding device for upper gastrointestinal endoscopy

Background and study aims  Infection control is essential when performing endoscopic procedures, especially during the COVID-19 pandemic. Therefore, we have developed a new shielding device called STEP for infection control in upper gastrointestinal endoscopy. Patients and methods  STEP consists of a mask worn by the patient and a drape that is connected to the mask and covers the endoscope. A suction tube attached to the mask prevents aerosols from spreading. The endoscopist operates the endoscope through the drape. Three endoscopists performed a total of 18 examinations using an upper endoscopy training model with and without STEP. Endoscopic images were evaluated by three other endoscopists, using a visual analog scale. We also simulated contact, droplet, and aerosol infection and evaluated the utility of STEP. Results  All examinations were conducted without a problem. Mean procedure time was 126.3 ± 11.6 seconds with STEP and 122.3 ± 10.0 seconds without STEP. The mean visual analog score was 90.7 ± 10.1 with STEP and 90.4 ± 10.0 without STEP. In the contact model, adherence of simulated contaminants was 4.9 ± 1.4 % without STEP and 0 % with STEP. In the droplet model, the number of simulated contaminants attached to the paper was 338 273 ± 90 735 pixels without STEP and 0 with STEP. In the aerosol model, the total number of particles was 346 837 ± 9485 without STEP and was significantly reduced to 222 ± 174 with STEP. Conclusions  No effect on examination time or endoscopic image quality was observed when using STEP in upper gastrointestinal endoscopy. Using STEP reduced the diffusion of simulated contaminants in all three infection models.

Effectiveness of Chemoradiotherapy for Metachronous Esophageal Squamous Cell Carcinoma

INTRODUCTION

Multiple Lugol-voiding lesions (LVLs) in the esophagus increase the risk of synchronous and metachronous development of esophageal squamous cell carcinoma (ESCC). Chemoradiotherapy (CRT) following endoscopic submucosal dissection (ESD) may reduce the incidence of metachronous ESCC, but few studies have investigated this. Therefore, we retrospectively examined the effect of CRT on metachronous ESCC and multiple esophageal dysplasias visible as multiple LVLs.

METHODS

This study reviewed 146 patients who underwent esophageal ESD and were determined pathologically to have noncurative resection. They were divided into 2 groups: those who received additional CRT (CRT group; n = 64) and those without additional treatment (control group; n = 82). Incidence of metachronous ESCC was analyzed using propensity scores to adjust for patient characteristics. The number of multiple LVLs was also examined.

RESULTS

The CRT group was significantly younger than the control group (mean 66.6 vs. 70.6 years, p = 0.011), had significantly deeper tumor invasion (p = 0.013), and had a significantly higher rate of lymphovascular invasion (47.8 vs. 12.2%, p < 0.001). The CRT group also had a significantly higher improvement rate of multiple LVLs (58.1 vs. 2.0%, p < 0.001). The LVLs after CRT had a distinctive irregular crack-shaped appearance. Metachronous ESCC was found in 7 patients (10.9%) in the CRT group and in 17 patients (20.7%) in the control group (p = 0.113). In propensity score-adjusted logistic regression analysis, the odds ratio for metachronous ESCC in the CRT group was 0.316 (p = 0.023). The occurrence rate was significantly lower in the CRT group than in the control group.

DISCUSSION/CONCLUSION

CRT may be effective in preventing metachronous ESCC.

The Evaluation of Esophageal Endoscopic Findings in Patients with Functional Esophagogastric Junction Outflow Obstruction

Objective Esophagogastric junction outflow obstruction (EGJOO) is a diagnosis of unclear significance that has become increasingly common with recent advances in high-resolution manometry (HRM). EGJOO can be divided into mechanical or functional obstruction. Functional EGJOO is considered an incomplete phenotype or an early stage of achalasia. However, little is known about the endoscopic findings in patients with functional EGJOO. Thus, we aimed to elucidate the endoscopic findings in patients with functional EGJOO and to identify patients at high risk for achalasia. Methods This was a single-center retrospective study. A total of 259 patients underwent esophagogastroduodenoscopy (EGD) along with HRM for upper gastrointestinal symptoms without any obstructive lesions or stricture between July 2013 and September 2019 in our institute. Among them, 31 patients were diagnosed with EGJOO. After excluding patients who had undergone previous endoscopic treatment, those who were diagnosed with eosinophilic esophagitis and those who had undergone EGD at other institutes, 23 patients were finally included with a diagnosis of functional EGJOO. The endoscopic findings were evaluated by three endoscopists. Results Five patients (21.7%) had an esophageal rosette sign (ERS). No patients had grade IV gastroesophageal flap valve, esophageal mucosal breaks, or abnormal retention of liquid or food in the esophagus. Manometric findings revealed that the median distal contractile integral value was significantly higher in patients with an ERS (n=5) than in those without it (n=18). Conclusion There were some patients with functional EGJOO who had an ERS, which is the characteristic endoscopic finding in achalasia.

Real-World Experience of Endoscopic Submucosal Dissection for Ulcerative Colitis-Associated Neoplasia

Introduction

Patients with ulcerative colitis (UC) have an increased risk of colorectal cancer. Some studies have recently investigated endoscopic resection of UC-associated neoplasia (UCAN), but the indications for endoscopic resection of UCAN remain controversial. This study sought to clarify the problems encountered in endoscopic submucosal dissection (ESD) for UCAN.

Methods

Seventeen lesions in 12 patients with UCAN (UCAN group) and 913 epithelial lesions in 824 control patients without UC (non-UC group) were evaluated. Both groups underwent ESD between January 2010 and December 2017 at Toranomon Hospital, Tokyo, Japan. Treatment outcomes of the 2 groups were compared retrospectively.

Results

Univariate analysis showed that the mean tumor size was significantly smaller in the UCAN group than in the non-UC group (25.1 ± 26.7 mm vs. 31.9 ± 19.0; p = 0.0023); however, the R0 resection rate was significantly lower in the UCAN group (70.6 vs. 92.9%; p = 0.001). Multivariate analysis showed a significantly lower negative horizontal margin rate in the UCAN group (odds ratio 11.3, 95% confidence interval 3.588-34.525; p = 0.000).

Discussion/Conclusion

ESD for UCAN is associated with a low-negative horizontal margin rate. When performing ESD for UCAN, it is important to evaluate the accuracy of the UCAN demarcation line, especially for flat lesions, using white-light imaging and chromoendoscopy as well as other modalities, including biopsy of surrounding tissues.

Impact of Anticoagulation Therapy on the Risk of Pulmonary Embolism and Bleeding Events in Patients with Isolated Distal Deep-Vein Thrombosis

The efficacy of anticoagulation for isolated distal DVT (id-DVT) is still uncertain and controversial. The aim of this study was to elucidate the risk of pulmonary embolism (PE) from id-DVT and to investigate the need for anticoagulants.We identified hospitalized patients with id-DVT diagnosed by lower-extremity ultrasonography (LEUS) from January 2013 to December 2013 in our institute. The exclusion criteria were the simultaneous detection of PE, a history of PE and/or DVT, and administration of anticoagulants before DVT detection. We retrospectively investigated the patient characteristics, treatments, occurrence of PE, and bleeding events between the groups with and without anticoagulation.A total of 151 patients met the criteria. The median (IQR) age was 74 (67, 80) years old, and there were 60 (39.7%) men. The median (IQR) observation period was 571 (160, 721) days. Significant differences in patient characteristics were observed for hypertension, operation time, consultation with experts, and follow-up LEUS. During the observation period, only one patient in the no-anticoagulation group who had traumatic cerebral hemorrhaging and was bedridden developed PE (non-massive type). However, there was no statistically significant difference in the occurrence of PE between the groups (log-rank P = 0.569). Bleeding episodes were observed in 9 of 151 (6.0%) patients, and all patients with bleeding events were taking anticoagulants (log-rank P < 0.001).The present retrospective single center study suggests that anticoagulation for id-DVT in inpatients with various backgrounds has a low efficacy to prevent the occurrence of PE and may increase bleeding events.

Feasibility of ultrathin endoscope for esophageal endoscopic submucosal dissection

Background and study aims  Endoscopic submucosal dissection (ESD) is widely performed for superficial esophageal cancer, but stricture after extensive resection is a major clinical problem. Using an ultrathin endoscope would enable endoscopists to approach lesions beyond the stricture. We evaluated the feasibility of an ultrathin endoscope for esophageal ESD. Methods  To perform ESD with an ultrathin endoscope, we developed a transparent hood and ESD knife. A total of 24 esophageal ESDs were performed by two endoscopists with excised and live porcine esophaguses. A GIF-Q260 J and Dual knife were used in the conventional group and the GIF-XP260NS and a newly developed knife were used in the ultrathin group. En bloc resection rates, perforation rates, and procedure times were compared. Results  All 24 lesions were resected en bloc without perforation. The mean procedure time was longer in the ultrathin group, although not significantly so (274.3 ± 81.8 s vs 435.8 ± 313.9 s, respectively; P  = 0.22). Conclusion  Although the procedure time was longer in the ultrathin group, en bloc resection was performed without any perforation. The findings indicate that esophageal ESD with an ultrathin endoscope is feasible.

Cytomegalovirus ileitis with protein-losing enteropathy in an immunocompetent adult

Symptomatic cytomegalovirus (CMV) infection in immunocompetent hosts has traditionally been considered to have a benign, self-limited course, and those who need intensive therapy are rare. Moreover, there are few reports of CMV infection with protein-losing enteropathy (PLE). We present an immunocompetent 74-year-old woman with CMV ileitis with PLE, which was diagnosed due to severe hypoalbuminemia and edema of the lower extremities. The patient was not immunocompromised, because a human immunodeficiency virus (HIV) antibody test was negative and she had not been taking immunosuppressants. Imaging tests including colonoscopy revealed ileitis with shallow widespread ulcers. ^99mTc-human serum albumin (HAS-D) scintigraphy suggested a possibility of protein loss in the ileum based on selective accumulation of nuclides in the right abdomen. Histological findings of the biopsy showed ulcerative mucosa with abnormal cells, which had enlarged nuclei with intranuclear inclusion bodies, including typical Cowdry A type. In immunohistochemistry, these cells were positive for anti-CMV staining. She was successfully treated with medical treatments including intravenous injection of ganciclovir (GCV) (500 mg/day). We described an extremely rare case of CMV ileitis with PLE in an immunocompetent adult who was treated successfully with medical treatments, including GCV.

Double Early Rectal Cancer Arising from Multiple Inflammatory Cloacogenic Polyps Resected by Endoscopic Submucosal Dissection

A 45-year-old man visited our institution due to the onset of hematochezia. He had a previous episode nine years earlier and colonoscopy at that time revealed multiple polyps, which were consistent with inflammatory cloacogenic polyps (ICPs) on the dentate line. Colonoscopy was performed again and two of the ICPs had grown. Both lesions were pathologically diagnosed as adenocarcinomas based on biopsies. Endoscopic submucosal dissection (ESD) was performed and the two lesions were diagnosed as double well-differentiated adenocarcinomas arising from ICPs. To our knowledge, this is the first reported case of double early rectal cancer in ICPs, which were followed endoscopically and successfully resected with ESD.

Large Fundic Gland Polyp Associated with Long-Term Proton Pump Inhibitor Administration Mimicking Gastric-Type Neoplasm

A 57-year-old man with a 10-year history of proton pump inhibitor (PPI) use presented with multiple fundic gland polyps (FGPs) including one >20 mm, whitish, semi-pedunculated polyp. Black spots and cobblestone-like mucosa were also observed in the stomach upon endoscopy; therefore, the lesion was considered to result from long-term PPI administration. Endoscopically, we diagnosed this polyp as a neoplastic lesion with gastric phenotype rather than a non-neoplastic lesion. Biopsy revealed an atypical glandular lesion that was indeterminate for neoplasia; therefore, we performed en bloc resection via endoscopic submucosal dissection (ESD) of the 22 × 22 × 10 mm-sized polyp. Histologically, the polyp was composed of hyperplastic foveolar epithelia in the upper half of the mucosa and hyperplastic fundic glands in the lower half of the mucosa, with luminal dilatation and parietal cell protrusion. The pathological diagnosis for this ESD specimen was FGP associated with PPI administration. We herein describe this rare case of a large FGP in Helicobacter pylori-uninfected gastric mucosa associated with long-term PPI administration, which was mimicking gastric-type neoplasm and resected by endoscopy.

Effects of alcohol consumption on multiple hepatocarcinogenesis in patients with fatty liver disease

AIM

The number of patients with fatty liver disease (FLD) is increasing globally. Ethanol consumption in FLD is known to be associated with an increased risk of hepatocellular carcinoma (HCC), but the effects of alcohol consumption on the occurrence of multiple HCCs remain unclear. We explored the relationship between the daily ethanol intake and the HCC number.

METHODS

This single-center retrospective study enrolled 114 patients without viral or immune hepatitis undergoing first-line HCC treatment who had been diagnosed with FLD by abdominal ultrasonography or a liver biopsy at the same time as or before HCC detection. We categorized patients into four groups according to the daily alcohol consumption (<20 g: non-alcoholic fatty liver disease, n = 45; 20-39 g: low-intermediate ethanol intake with FLD, n = 13; 40-69 g: high-intermediate ethanol intake with FLD, n = 31; ≥70 g: alcoholic fatty liver disease, n = 25). The relationship between the daily ethanol consumption and the number of HCCs (single or multiple) was examined.

RESULTS

The risk of multiple HCCs was significantly higher in the high-intermediate ethanol intake with FLD (HR 2.89, 95% CI 1.04-8.02, P = 0.042) and alcoholic fatty liver disease (HR 3.14, 95% CI 1.07-9.22, P = 0.037) groups than in the others. A multivariate analysis showed that a daily ethanol intake ≥40 g was associated with a significantly increased risk of multiple HCCs (HR 2.82, 95% CI 1.16-6.88, P = 0.023).

CONCLUSIONS

Our findings suggest that a high daily ethanol intake might lead to multiple hepatocarcinogenesis in patients with FLD.

Esophageal Hematoma Associated with the Bolus Ingestion of Hot Coffee

A 59-year-old woman presented with pharyngeal discomfort and dysphagia starting the previous day. Esophagogastroduodenoscopy revealed a longitudinal reddish area and hematoma mainly on the left wall of the esophagus. On the previous day, she had felt a piece of meat sticking in her throat while eating; she therefore rapidly gulped down some hot coffee to hasten the passage of the meat. Based on the history, we diagnosed her endoscopic findings as esophageal hematoma and thermal injury associated with hot coffee. We herein describe a case of an acute esophageal hematoma and thermal injury and the clinical course following endoscopy.

Relativistic magnetic reconnection in laser laboratory for testing an emission mechanism of hard-state black hole system

Magnetic reconnection in a relativistic electron magnetization regime was observed in a laboratory plasma produced by a high-intensity, large energy, picoseconds laser pulse. Magnetic reconnection conditions realized with a laser-driven several kilotesla magnetic field is comparable to that in the accretion disk corona of black hole systems, i.e., Cygnus X-1. We observed particle energy distributions of reconnection outflow jets, which possess a power-law component in a high-energy range. The hardness of the observed spectra could explain the hard-state x-ray emission from accreting black hole systems.

Exploration of the characteristics of chronotypes in upper gastrointestinal tract diseases: a multicenter study in Japan

Characteristics of the chronotypes of patients with gastrointestinal disease are unknown. We evaluated chronotypes of patients with upper gastrointestinal diseases with the Munich ChronoType Questionnaire (MCTQ). A total of 2027 subjects from 29 institutions in Japan who had undergone esophagogastroduodenoscopy were asked to answer the MCTQ. The subjects' chronotypes were divided into three groups (early, intermediate, and late chronotype) using the sleep-corrected mid-point of sleep on free days (MSF_SC) values. According to their endoscopic diagnosis and abdominal symptoms, the subjects were divided into the reflux esophagitis (RE) group, gastroduodenal ulcer (GDU) group, upper gastrointestinal carcinoma (CA) group, functional dyspepsia (FD) group, non-FD group, and control group. In total, 1128 subjects were eligible for the analysis. The MSF_SC (average ± standard deviation, clock hours, h) of each disease group was as follows: control group: 02.51 ± 1.22, non-FD group: 02.69 ± 1.14, FD group: 02.91 ± 1.19, RE group: 02.58 ± 1.05, GDU group: 02.47 ± 1.31, and CA group: 02.11 ± 1.08 h. Compared to the control group, the rate of late chronotype of the FD group significantly increased to 33.3%, whereas that of early chronotype of the CA group significantly increased to 38.3% (P = .0177 and 0.0036, respectively). In both the FD and CA groups, chronotype was the independent factor related to the diseases. The adjusted odds ratio of late chronotype to early chronotype was 3.01 [95% CI, 1.23-7.35] in the FD group and 0.44 [95% CI, 0.23-0.85] in the CA group. In conclusion, late chronotype was common in patients with FD, and early chronotype was common in patients with upper gastrointestinal carcinoma.

Clinicopathological features of colorectal polyps and risk of colorectal cancer in acromegaly

OBJECTIVE

Patients with acromegaly are at increased risk of colorectal polyps. However, their risk of colorectal cancer remains unclear. This study aimed to identify the histopathological features of colorectal polyps in patients with acromegaly and compare their risk of colorectal cancer with that in healthy controls.

METHODS

The study participants were 178 patients who underwent Hardy's operation and perioperative colonoscopy at our hospital between April 2008 and September 2016. For the control group, we randomly selected 356 age- and sex-matched patients who underwent colonoscopy at our hospital during the same period. The incidence, size, location, and histology of the colorectal polyps detected were compared between the groups.

RESULTS

Colorectal polyps were detected in 66.8% of the acromegaly group and 24.2% of the control group (P < 0.001). The average number and size of the polyps were 2.44 and 4.74 mm, respectively, in the acromegaly group and 1.77 and 3.89 mm in the control group (P = 0.001). Polyps in the acromegaly group were more likely to be in the rectosigmoid region (P = 0.006). In the acromegaly group, the frequency of polyps ≥5 mm was 34.3% and that for polyps ≥10 mm was 15.2%; the respective values were 7.6% and 2.2% in the control group (P < 0.001). We found no evidence of between-group histopathological differences in the polyp specimens resected by endoscopy.

CONCLUSIONS

Patients with acromegaly are at an increased risk of colorectal polyps, especially in the rectosigmoid region. However, there is no pathological evidence that they are at greater risk of colorectal cancer than the general population.

Utility of autologous fibrin glue and polyglycolic acid sheet for preventing delayed bleeding associated with antithrombotic therapy after gastric ESD

Background and study aims  Delayed bleeding is one of the most serious adverse events of gastric endoscopic submucosal dissection (ESD), especially in patients taking antithrombotic therapy. This study aimed to evaluate the utility and safety of a shielding method with autologous fibrin glue and polyglycolic acid (PGA) sheets for patients undergoing gastric ESD who are receiving antithrombotic therapy. Patients and methods  One hundred twenty-three patients who were treated with gastric ESD while receiving antithrombotic therapy between December 2014 and September 2017 were enrolled in this study. Patients who received the shielding method were classified into the shielding group. Others were classified into the conventional group. Various clinico-pathological factors were retrospectively compared between the two groups. Results  The shielding group consisted of 38 patients, and the conventional group consisted of the remaining 85 patients. In the shielding group, the rate of continuation of antithrombotic therapy was significantly higher (68.4 % vs 41.2 %). Incidence of delayed bleeding was lower in the shielding group (2.6 %, 1/38) than in the conventional group (14.1 %, 12/85). In the propensity score-adjusted logistic regression analysis, the delayed bleeding rate in the shielding group tended to be lower than in the conventional group ( P  = 0.070). Allogeneic transfusion was performed in eight patients (8/85, 9.4 %) in the conventional group and none in the shielding group ( P  = 0.047). No adverse event associated with endoscopic shielding were observed in the shielding group. Conclusions  This study suggests that a shielding method with autologous fibrin glue and PGA sheet effectively prevents delayed bleeding after gastric ESD in patients receiving antithrombotic therapy.

A pilot study of a novel variable-stiffness stylet for efficient colonoscope insertion with <i>ex-vivo</i> colon model

Objectives: The variable-stiffness colonoscope is reportedly useful for making colonoscope insertion easier. However, this function is not associated with all colonoscopes. We developed a variable-stiffness stylet that can be inserted into the endoscope instrumentation channel to change the rigidity of the endoscope. Methods: We developed a stylet with adjustable stiffness and investigated its utility in colonoscope insertion using an ex-vivo model. Four endoscopists performed 24 colonoscope insertions, alternating between using the stylet (Stylet method) and the conventional method. We assessed insertion rate, rate of applying abdominal compression, and insertion time between the two groups. Results: In all procedures, the endoscope was inserted up to the cecum. There were significantly fewer external abdominal compressions with the Stylet method (1/12, 8.3%) compared to the conventional method (6/12, 50%). The insertion time was shorter with the Stylet method (140.9 ± 53.7 s) compared to the conventional method (181.3 ± 64.9 s). Conclusions: Using the variable-stiffness stylet, currently under development, resulted in significantly fewer external abdominal compressions and tended to have shorter insertion time.

Quantitative Modeling and Simulation in PMDA: A Japanese Regulatory Perspective

In Japan in October 2016, the Pharmaceuticals and Medical Devices Agency (PMDA) began to receive electronic data in new drug applications (NDAs). These electronic data are useful to conduct regulatory assessment of sponsors’ submissions and contribute to the PMDA's research. In this article, we summarize the number of submissions of quantitative modeling and simulation (M&S) documents in NDAs in Japan, and we describe our current thinking and activities about quantitative M&S in PMDA.

Probing weak localization in chemical vapor deposition graphene wide constriction using scanning gate microscopy

Low-temperature scanning gate microscopy (LT-SGM) studies of graphene allow one to obtain important spatial information regarding coherent transport such as weak localization (WL) and universal conductance fluctuations. Although fascinating LT-SGM results on pristine graphene prepared by mechanical exfoliation have been reported in the literature, there appears to be a dearth of LT-SGM results on chemical vapor deposition (CVD)-grown graphene whose large scale and flexible substrate transferability make it an ideal candidate for coherent electronic applications. To this end, we have performed LT-SGM studies on CVD-grown graphene wide constriction (0.8 μm), which can be readily prepared by cost-effective optical lithography fully compatible with those in wafer foundry, in the WL regime. We find that the movable local gate can sensitively modulate the total conductance of the CVD graphene constriction possibly due to the intrinsic grain boundaries and merged domains, a great advantage for applications in coherent electronics. Moreover, such a conductance modulation by LT-SGM provides an additional, approximately magnetic-field-independent probe for studying coherent transport such as WL in graphene and spatial conductance variation.

Biological index of environmental lead pollution: accumulation of lead in liver and kidney in mice

Lead (Pb) is known to be highly poisonous, and the acute poisoning of Cd causes the abdominal pains, vomiting, and shock. The digestive and nervous symptom is observed in the chronic lead poisoning. It was also known that the defect in hemoglobin synthesis by Pb produce anemia. The release of Pb into the environment presents a source of exposure for wild animals. In this study, we examined the utility of a new Pb-monitoring index in mice administered Pb. A solution containing 0.02, 0.2, 2, or 4 ppm lead chloride (PbCl2) was administered intraperitoneally to mice, and the Pb contents of the kidney and liver were determined at designated time points. The mean Pb content of both organs increased depending on the administered Pb dosage. Although the results of control was near the detection limits, the administration of 4 ppm in 4 weeks resulted in Pb levels of 260 mg ppm/wet weight and 110 ppm wet weight in the kidney and liver, respectively. However, there were no significant relationships among administered dose, duration of Pb treatment, and liver or kidney Pb content. Then, values in all mice administered control or 0.02 mg Pb were located inside the ellipse, representing the confidence area of the new index, and values in all mice administered more than 2 mg Pb were located outside the ellipse. These results confirm that animals exposed to high concentrations of Pb would be detected by this new index.

Metal-insulator transition in the quasi-one-dimensional transport of fractional quantum Hall states

We investigate edge state transmission in quantum point contacts (QPCs) in the fractional quantum-Hall regime, finding behavior reminiscent of a metal-insulator transition. The transition is suggested by an unusual behavior of the differential conductance in the fractional-quantum-Hall regime, and by the presence of a fixed point and universal scaling in the temperature dependence of the linear conductance. Noting that the 0.7 feature evolves continuously into a last fractional plateau at high magnetic fields, we suggest that this still unresolved feature may itself be viewed as a manifestation of a local, microscopic, metal-insulator transition.

Scanning gate imaging of a disordered quantum point contact

Scanning gate microscopy (SGM) is a novel technique that has been used to image characteristic features related to the coherent electron flow in mesoscopic structures. For instance, SGM has successfully been applied to study peculiar electron transport properties that arise due to small levels of disorder in a system. The particular case of an InGaAs quantum well layer in a heterostructure, which is dominated by a quasi-ballistic regime, was analyzed. A quantum point contact fabricated onto this material exhibits conduction fluctuations that are not expected in typical high-mobility heterostructures such as AlGaAs/GaAs. SGM revealed not only interference patterns corresponding to specific conductance fluctuations but also mode-dependent resistance peaks corresponding to the first and second quantum levels of conductance (2e(2)/h) at zero magnetic field. On the other hand, clear conductance plateaus originating from the integer quantum Hall effect were observed at high magnetic fields. The physical size of incompressible edge channels was estimated from cross-sectional analysis of these images.

On the zero-bias anomaly and Kondo physics in quantum point contacts near pinch-off

We investigate the linear and non-linear conductance of quantum point contacts (QPCs), in the region near pinch-off where Kondo physics has previously been connected to the appearance of the 0.7 feature. In studies of seven different QPCs, fabricated in the same high-mobility GaAs/AlGaAs heterojunction, the linear conductance is widely found to show the presence of the 0.7 feature. The differential conductance, on the other hand, does not generally exhibit the zero-bias anomaly (ZBA) that has been proposed to indicate the Kondo effect. Indeed, even in the small subset of QPCs found to exhibit such an anomaly, the linear conductance does not always follow the universal temperature-dependent scaling behavior expected for the Kondo effect. Taken collectively, our observations demonstrate that, unlike the 0.7 feature, the ZBA is not a generic feature of low-temperature QPC conduction. We furthermore conclude that the mere observation of the ZBA alone is insufficient evidence for concluding that Kondo physics is active. While we do not rule out the possibility that the Kondo effect may occur in QPCs, our results appear to indicate that its observation requires a very strict set of conditions to be satisfied. This should be contrasted with the case of the 0.7 feature, which has been apparent since the earliest experimental investigations of QPC transport.

Tuning the Fano resonance with an intruder continuum

Through a combination of experiment and theory we establish the possibility of achieving strong tuning of Fano resonances (FRs), by allowing their usual two-path geometry to interfere with an additional, "intruder", continuum. As the coupling strength to this intruder is varied, we predict strong modulations of the resonance line shape that, in principle at least, may exceed the amplitude of the original FR itself. For a proof-of-concept demonstration of this phenomenon, we construct a nanoscale interferometer from nonlocally coupled quantum point contacts and utilize the unique features of their density of states to realize the intruder. External control of the intruder coupling is enabled by means of an applied magnetic field, in the presence of which we demonstrate the predicted distortions of the FR. This general scheme for resonant control should be broadly applicable to a variety of wave-based systems, opening up the possibility of new applications in areas such as chemical and biological sensing and secure communications.