Endoscopic hand suturing for mucosal defect closure after gastric endoscopic submucosal dissection may reduce the risk of postoperative bleeding in patients receiving antithrombotic therapy

OBJECTIVES

Endoscopic hand suturing (EHS) is expected to decrease the risk of post-endoscopic submucosal dissection (ESD) bleeding by closing mucosal defects. We investigated the efficacy of EHS after gastric ESD in patients with antithrombotic agents.

METHODS

In this prospective single-arm trial, patients taking antithrombotic agents for cardiovascular disease, arrhythmia, cerebrovascular disease and/or peripheral arterial disease and having <3-cm gastric neoplasms were recruited. The mucosal defects after ESD were closed by EHS in which the needle was delivered through an overtube, and the mucosal rim of the defect was continuously sutured in a linear fashion by manipulating the needle grasped with the needle holder, followed by cutting the remnant suture and retrieval of the needle. The primary endpoint was the incidence of postoperative bleeding within 4 weeks after ESD.

RESULTS

Twenty-two lesions in 20 patients (continuing antiplatelet agents in 11, anticoagulant agents in eight, both in one) underwent ESD followed by EHS. All defects (median size, 30 mm; range, 12-51 mm) were completely closed by EHS and remained closed on postoperative day 3. The median number of stitches was six (range, 4-8) and median suturing time was 36 (range, 24-60) min. There were no adverse events during/after EHS or postoperative bleeding.

CONCLUSIONS

Postoperative bleeding was not observed in patients taking antithrombotic agents without perioperative cessation. EHS appears to be useful for prevention of post-gastric ESD bleeding in high-risk patients. (Clinical registration number: UMIN000024184).

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.

Feasibility study comparing underwater endoscopic mucosal resection and conventional endoscopic mucosal resection for superficial non-ampullary duodenal epithelial tumor < 20 mm

BACKGROUND AND AIM

Underwater endoscopic mucosal resection (UEMR) has been reported as an alternative to conventional EMR for superficial non-ampullary duodenal epithelial tumors (SNADET). However, the detailed outcomes are unclear. This study aimed to compare the clinical outcomes between UEMR and EMR for SNADET <20 mm.

PATIENTS AND METHODS

This is a retrospective observational study using a prospective maintained database. From November 2017 to December 2018, 104 consecutive cases of attempted UEMR for SNADET <20 mm were prospectively allocated. A total of 240 cases of attempted EMR were chosen as historical controls. We compared technical success rate, defined as the resection rate without conversion to ESD; en bloc resection rate; R0 resection rate; and adverse event rate. Next, multivariate analyses were constructed to identify predictors of conversion to ESD, piecemeal resection, and RX or R1 (RX/R1) resection.

RESULTS

Technical success rate of UEMR was significantly higher than that of EMR (87% and 70%, P < 0.01). En bloc resection and R0 resection rates of UEMR were significantly lower than those of EMR (en bloc resection: 87% vs 96%, P < 0.01; R0 resection: 67% vs 80%, P = 0.05). Concerning adverse events, there were no significant differences. In multivariate analyses, attempted EMR, lesion size and depressed type were independent predictors of conversion to ESD. Attempted UEMR was an independent predictor of piecemeal resection and RX/R1 resection.

CONCLUSION

The present study indicated that UEMR could be a feasible endoscopic resection method for SNADET (UMIN000025442).

Endoscopic suturing promotes healing of mucosal defects after gastric endoscopic submucosal dissection: endoscopic and histologic analyses in in vivo porcine models (with video)

BACKGROUND AND AIMS

Endoscopic suturing of mucosal defects after endoscopic submucosal dissection (ESD) is expected to prevent postoperative adverse events. We aimed to endoscopically and histologically evaluate the healing process of post-ESD mucosal defects closed with endoscopic hand suturing (EHS) in in vivo porcine models.

METHODS

Twelve mucosal defects (2 cm in size) were created in 2 pigs (6 defects per pig). Initially, 2 defects were created: one was closed with EHS (sutured group) and the other was kept open (control group). On postoperative days (PODs) 7 and 14, 2 additional defects were created in each session, and they were treated in the same manner as in the initial procedure. On POD 21, the entire stomach, with the 6 lesion sites, was extracted for histologic evaluation after endoscopic observation.

RESULTS

Endoscopically, all sutured sites remained closed in all sessions (PODs 7, 14, and 21). Histologically, on POD 14, the epithelium and muscularis mucosae were appropriately connected. The mucosae were covered with the epithelium without inversion of the mucosal edge in the sutured group, whereas the ulcer bed was exposed in the control group. Furthermore, the degree of neovascularity and fibroblasts in the submucosa was smaller in the sutured group than that in the control group.

CONCLUSIONS

Our findings suggest that endoscopic suturing promotes healing of post-ESD mucosal defects histologically in in vivo porcine models. Thus, endoscopic mucosal closure after ESD might be clinically useful for the prevention of delayed perforation/bleeding if secure suturing is performed endoscopically.

How I do it: Endoscopic diagnosis for superficial non-ampullary duodenal epithelial tumors

There are no reports on detailed endoscopic diagnosis of superficial non-ampullary duodenal epithelial tumors (SNADET) except for relatively small case series. Herein, we conducted a prospective observational study to investigate the relationship between endoscopic findings and histopathological diagnosis of SNADET. A total of 163 SNADET diagnosed using magnified endoscopic examination with image-enhanced endoscopy (IEE-ME) were prospectively registered in this study. We investigated location, size, macroscopic type, color, and IEE-ME findings including surface structure (closed- or open-loop) and presence of white opaque substance (WOS) in SNADET. We analyzed association between these findings and histopathological diagnosis of SNADET based on the Vienna classification (VCL) using logistic regression analysis. In univariate analysis, lesion size, superficial structure, and WOS deposition showed statistical significance, and the oral side of the lesion location showed statistical tendency for association with VCL C4/5. In multivariate analysis, lesion size (odds ratio [OR], 2.92; 95% CI, 1.94-4.39; P < 0.05) and negative WOS (OR, 5.59; 95% CI, 1.72-18.1; P < 0.05) were significantly associated with VCL C4/5 lesions. Superficial structures with a closed-loop pattern on the surface showed statistical tendency for predicting VCL C4/5 lesions (OR, 2.15; 95% CI, 0.86-5.37; P = 0.10). Based on these findings, we concluded that negative WOS by IEE-ME and lesion size were independent predictors of VCL C4/5 SNADET. These factors may help us to understand of pathophysiology of SNADET and to select appropriate therapeutic strategies.

Feasibility of endoscopic submucosal dissection for colorectal neoplasia at anastomotic sites: a retrospective study

BACKGROUND

Metachronous colorectal lesions sometimes occur at anastomotic sites following colorectal surgery, which increases the risk of developing colorectal cancer. However, these lesions are difficult to treat even with minimally invasive methods such as endoscopic submucosal dissection (ESD). Thus, we aimed to evaluate the outcomes of ESD for colorectal lesions at anastomotic sites following colorectal surgery.

METHODS

We retrospectively investigated 11 patients with post-surgical colorectal lesions at anastomotic sites who later underwent ESD from May 2010 to April 2019 at Keio University Hospital, Tokyo, Japan. We examined the patients' background (tumor location, macroscopic type, tumor size, histological type, and depth of invasion) and treatment outcomes (procedure duration, en bloc resection rate, R0 resection rate, and adverse events).

RESULTS

The patients' mean age was 66 years. There were two lesions in the transverse colon, six in the rectum, one in the anal canal, and two in the ileal pouch. The median tumor size was 25 mm. The macroscopic types were the protruded type (1 lesion) and the flat or depressed type (10 lesions). The pathological diagnoses were adenoma (4 lesions), intramucosal cancer (corresponding to high-grade dysplasia) (6 lesions), and muscularis propria cancer (1 lesion). The median procedure duration was 50 min; en bloc resection rate was 88.9% and R0 resection rate was 66.7%. The only adverse event was delayed post-ESD bleeding.

CONCLUSIONS

A high en bloc resection rate without perforation was achieved with ESD for lesions at anastomotic sites. Although ESD for lesions at anastomotic sites is a technically challenging procedure because of severe submucosal fibrosis, this approach could prevent the need for repeated surgical resection.

Salvage endoscopic submucosal dissection for incompletely resected esophageal or gastric neoplasms (case series)

Background and study aims  Given that positive lateral margins indicate possible residual carcinoma, salvage endoscopic submucosal dissection (ESD) should be considered for curative therapy. Presence of submucosal fibrosis, however, makes the procedure difficult to perform. We present our case series to discuss the feasibility of salvage ESD and the timing of the procedure.

Predictors of technical difficulty with duodenal ESD

Background and study aims  Duodenal endoscopic submucosal dissection (ESD) is still considered technically challenging; however, few studies have objectively analyzed predictors of the technical difficulty. Therefore, the aim of the current study was to elucidate predictors of the technical difficulty of duodenal ESD. Patients and methods  This was a retrospective observational study. From June 2010 to June 2017, a total of 174 consecutive patients with superficial duodenal epithelial neoplasia who underwent ESD were included in this study. We tried to identify predictors for technical difficulty of ESD by defining technical difficulty as either procedure time > 100 minutes or intraprocedural perforation. Moreover, we constructed a scoring system consisting of factors that were significant in the multivariate analysis. Results  The proportion of patients with technical difficulty was 34.5 %. In the multivariate analysis, lesion location in flexural part [odds ratio (OR), 2.61; 95 % confidence interval (CI), 1.02 - 6.68], larger lesion size (> 40 mm) (OR, 5.26; 95% CI, 2.15 - 12.9), and occupied circumference > 50 % of the duodenum (OR, 5.80; 95 % CI, 1.83 - 18.4) were associated with technical difficulty. Conclusion  A lesion location in flexural part, lesion size >40 mm and occupied circumference > 50 % were risk factors for technical difficulty of duodenal ESD.

Dual red imaging: a novel endoscopic imaging technology visualizing thick blood vessels in the gastrointestinal wall

Background  Dual red imaging (DRI), a novel image-enhanced endoscopy (IEE) technology, has the potential to improve the visibility of blood vessels in deeper tissue using 600 nm and 630 nm wavelength lights in the red band. Aim  To confirm the feasibility of DRI in visualization of vessels in deeper tissue and identify pathologically the features of blood vessels visualized by DRI. Methods  Study 1: visibility of blood vessels was assessed by five observers in 137 pairs of DRI and white light imaging (WLI) images. The scores for the visibility of thick blood vessels were measured for randomized images and compared with the scoring template as a reference. The difference in visibility score between DRI and WLI was compared in each pair of images. Study 2: blood vessels detected only by DRI were examined pathologically using two pig stomachs. Results  Study 1: The mean visibility scores of DRI and WLI for each observer were 1.69 - 2.26 and 1.31 - 1.67, respectively. The mean difference in visibility score and 95 % confidence interval for the five observers was 0.59 [0.46 - 0.72], 0.54 [0.40 - 0.68], 0.34 [0.18 - 0.49], 0.51 [0.36 - 0.66], and 0.71 [0.54 - 0.88]. The visibility was statistically significantly better in DRI than in WLI for all observers ( P  < 0.0001). Study 2: three blood vessels were observed only by DRI. All of these blood vessels were located at a depth of 1000 - 1500 µm from the mucosal surface. The diameter of these blood vessels exceeded 80 - 200 µm. Conclusions  DRI can feasibly detect thick blood vessels in the deep mucosa or submucosa of the gastrointestinal tract.

Current Status and Challenges of Endoscopic Treatments for Duodenal Tumors

BACKGROUND

Superficial tumors of the duodenum, other than ampullary tumors, have been traditionally considered rare. However, reports of this kind of tumor have increased in recent times, and the demand for minimally invasive treatments have also increasing.

SUMMARY

Adenomas and intramucosal carcinomas are target lesions for treatment. A preoperative diagnosis has not been established, but unnecessary biopsies increase the difficulty of treatment and should be avoided. Cold snare polypectomy, endoscopic mucosal resection (EMR), and underwater EMR are treatment options for small lesions. Endoscopic submucosal dissection enables secure resection even for large lesions, but it is technically demanding and associated with a higher complication rate. After endoscopic resections, exposure of digestive juices is believed to cause delayed complications. To prevent these complications, several closing and covering methods are proposed, with favorable clinical results. Key message: A treatment method should be chosen based on each patient's situation. With any of the treatment methods, post-resection measures are required to prevent delayed complications. Secure closure of resection wounds seems promising.

Haemostasis treatment using dual red imaging during endoscopic submucosal dissection: a multicentre, open-label, randomised controlled trial

INTRODUCTION

Patients scheduled to undergo oesophageal, gastric and colorectal endoscopic submucosal dissection (ESD) are to be investigated to verify the efficacy of dual red imaging (DRI) for establishing haemostasis during ESD.

METHODS AND ANALYSIS

The trial is designed as a multicentre, open-label randomised, parallel-group, controlled intervention study. Registered patients will be randomly assigned to DRI and white light imaging (WLI) groups. In the DRI group, the mucosal incision and submucosal dissection will be performed by WLI, and haemostasis will be managed by DRI when bleeding occurs. In the WLI group, the mucosal incision and submucosal dissection are to be performed by WLI and the haemostasis management is to be performed by WLI. The primary endpoint is the time from the recognition of bleeding up to the achievement of complete haemostasis (haemostasis time). The secondary endpoints are the operation time, the proportion of cases in which perforation occurs, and the psychological stress experienced by the endoscopist during haemostasis treatment.

ETHICS AND DISSEMINATION

This trial was approved by the Keio University Review Board for Clinical Trials (5 December 2016).

DISCUSSION

This will be the first multicentre collaborative research using DRI for haemostasis treatment during ESD. When the safety and simplicity of DRI as a treatment for haemostasis during ESD can be proven, the ESD procedure can be simplified and disseminated more widely in clinical practice.

TRIAL REGISTRATION NUMBER

UMIN000025134.

Treatment Results of Endoscopic Mucosal Resection with a Ligation Device for Duodenal Neuroendocrine Tumors

Objective The vertical margin of neuroendocrine tumors (NETs) removed by endoscopic mucosal resection (EMR) is often tumor-positive. We examine the treatment results of endoscopic mucosal resection with a ligation device (EMR-L) for the removal of duodenal NETs located in the submucosal layer without metastasis. EMR-L can be performed with less technical skill, and the ligation device reduces the rate of positive vertical margin. Methods Ten consecutive patients with 10 duodenal NETs resected by EMR-L were enrolled. All of the lesions were located in the submucosal layer, were assessed to be free of metastasis, and were confirmed to be NETs pathologically by an endoscopic biopsy. The endoscopic results, pathological results, and prognosis were all examined. Results The en bloc resection rate and endoscopic complete resection rate were both 100%. Complete resection was achieved pathologically in 7 lesions (70.0%). The vertical margins were negative in all cases. Lymphatic vessel invasion was observed in three patients, all of whom underwent additional surgery with lymph node dissection (one of them also exhibited blood vessel invasion and a positive horizontal margin). No evidence of residual tumors or lymph node metastasis was observed in any of the patients. No recurrence was observed in any of the 10 patients (mean follow-up period: 18.6 months). One patient (10.0%) experienced intraoperative bleeding. Perforation occurred in 1 patient (10.0%), but the condition was managed well by conservative therapy. Conclusion EMR-L was an acceptable method for endoscopically resecting submucosal duodenal NETs, and the NETs resected by EMR-L were tumor-negative in the vertical margins.

Clinical impact of closure of the mucosal defect after duodenal endoscopic submucosal dissection

BACKGROUND AND AIMS

Delayed adverse events (bleeding or perforation) are major concerns associated with duodenal endoscopic submucosal dissection (ESD). The aim of this study was to assess the efficacy of prophylactic closure of the mucosal defect after duodenal ESD.

METHODS

This is a retrospective study from a university hospital. One hundred sixty-eight patients (173 lesions) who underwent duodenal ESD between July 2010 and June 2017 were included in this study. The study participants were divided into 3 subgroups according to the degree of closure: complete group, incomplete group, and unclosed group. The proportion of delayed adverse events, maximum serum level of C-reactive protein (CRP), and total length of hospital stay were compared among these subgroups. Moreover, a multivariate logistic regression model was constructed to identify the risk factors for delayed adverse events.

RESULTS

The proportion of delayed adverse events in the complete group, incomplete group, and unclosed group were 1.7%, 25%, and 15.6%, respectively. The difference between the complete group and the other groups was significant (P < .01). The maximum serum CRP level was much lower (1.51 ± 2.18 mg/dL vs 6.28 ± 10.0 mg/dL, P < .01), and the length of hospital stay was significantly shorter in the complete group than in the incomplete/unclosed group (median [range] 5 [5-14] days vs 8 [4-59] days, P < .01). Multivariate analysis revealed that complete closure had a significant decrease in delayed adverse events (odds ratio [OR], 0.055; 95% confidence interval [CI], 0.01-0.29; P < .01), and a lesion located distal from the descending part showed a statistical tendency to an increase in delayed adverse events (OR, 4.48; 95% CI, 0.85-23.6; P = .08).

CONCLUSION

The present study revealed that complete closure of the mucosal defect after duodenal ESD significantly decreased the number of delayed adverse events and improved other outcomes.

Outcomes of endoscopic resection for superficial duodenal epithelial neoplasia

BACKGROUND AND AIMS

Pancreaticoduodenectomy is an invasive procedure, and endoscopic resection (ER) is an alternative therapy. However, details regarding the outcomes of ER are unknown, especially for superficial duodenal epithelial neoplasia (SDET). The aim of this study was to elucidate the outcomes of ER for SDET and to compare EMR with endoscopic submucosal dissection (ESD).

METHODS

This was a retrospective observational study. From June 2010 to June 2017, 320 cases of endoscopically resected SDET (146 EMR-treated cases and 174 ESD-treated cases) were included in this study. We analyzed the proportions of en bloc resection, R0 resection, perforation, and bleeding as outcomes of ER and compared outcomes between the EMR and ESD groups. Next, we collected data on the features and clinical course of cases with adverse events.

RESULTS

The proportions of en bloc resection and R0 resection among all cases were 96.6% and 83.4%, respectively. In over 95% of cases, ESD achieved en bloc resection, regardless of lesion size. The incidences of perforation and bleeding were 8.8% and 3.4%, respectively, and the former was largely successfully managed by conservative treatment. The mortality rate was 0%, and all patients were discharged with a median hospital stay of 8.5 days (range, 4-52 days). Evaluation of the hospital stay duration according to lesion circumference revealed a significantly longer duration for lesions present on the medial wall than for other lesions (median 41 vs 7 days, P = .0331).

CONCLUSION

The present study revealed that ER achieved secure en bloc resection, with the treatment type (ESD or EMR) selected according to the lesion size. A lesion located on the medial wall was associated with worse outcomes, such as prolonged hospital stay after perforation.

A Gastric Follicular Lymphoma Presenting as a Submucosal Tumor with a Diagnosis Determined by Endoscopic Resection

We herein report the case of 74-year-old man with gastric follicular lymphoma resected by endoscopic submucosal dissection (ESD). A submucosal tumor 7 mm in diameter was detected at the gastric middle body. Endoscopic ultrasonography showed a homogenous hypoechoic tumor localized in the submucosa. The tumor was removed by ESD immediately, before further tumor growth would preclude endoscopic resection. The pathological findings indicated follicular lymphoma (FL) with negative horizontal and vertical margins. The clinical stage of FL was confirmed to be stage I by extensive work-up procedures, including contrast-enhanced computed tomography, fluorodeoxyglucose-positron emission tomography, esophagogastroduodenoscopy, and colonoscopy. The patient remains in complete remission without any treatment.

Endoscopic string clip suturing method: a prospective pilot study (with video)

BACKGROUND AND AIMS

We developed a suturing method with string and clips for a single-channel endoscope. The feasibility of the string clip suturing method is evaluated in this prospective pilot study.

METHODS

This study involved 10 consecutive patients who underwent endoscopic submucosal dissection (ESD) for a duodenal tumor. Polyester string was tied to the arm of a partially out thrust clip. The clip and string can be passed through the instrument channel (3.2 mm) of a single-channel endoscope. The clip with string was placed at the distal edge of the large mucosal defect. A second clip was hooked on the string and placed on the opposite side. Both clips were gathered by pulling the free end of the string, and additional clips were placed to achieve complete closure. This method was compared with that for the previous 10 patients without mucosal closure after duodenal ESD.

RESULTS

Mean size of resected specimens was 39.1 ± 12.4 mm. The success rate of the string clip suturing method was 100% (10/10). The mean procedure time was 23.4 ± 13.8 minutes. Perforation during ESD occurred in 1 patient and was successfully closed by this method. None of the treated patients developed serious adverse events after the procedure. Compared with the no-suture group, the length of stay was significantly shorter (P = .038).

CONCLUSION

The string clip suturing method appears to be a safe and effective method for closure of large mucosal defects. (Clinical trial registration number: UMIN000023698.).

Rebamipide solution: a novel submucosal injection material to promote healing speed and healing quality of ulcers induced by endoscopic submucosal dissection

BACKGROUND AND AIMS

Rebamipide is administered perorally to protect the gastric mucosa. We assessed the efficacy and safety of a novel rebamipide solution as a submucosal injection material for endoscopic submucosal dissection (ESD) using an in vivo porcine model.

METHODS

An endoscopist blinded to the test agents performed ESDs of hypothetical 30 mm lesions using a 2% rebamipide solution at 2 sites (rebamipide group) and a saline solution at 2 other sites (control group) in the stomachs of 8 pigs. The technical outcomes were compared between the 2 groups. The gastric ulcer stages were evaluated by endoscopy once weekly for 4 weeks after the ESD to determine the healing score (1-6). The pigs were killed at 1 week (n = 2), 2 weeks (n = 2), and 4 weeks (n = 4) after the ESD for pathologic evaluation of ESD-induced ulcers and scarring.

RESULTS

There were no significant differences in any of the technical outcomes between the 2 groups, and no adverse events related to the ESD in any of the animals. The healing score was significantly higher in the rebamipide group than in the control group at 2 weeks (P = .027), 3 weeks (P = .034), and 4 weeks (P = .012). In the histopathologic assessment, fibrosis was significantly less extensive in the rebamipide group than in the control group at 2 weeks (P = .02) and 4 weeks (P = .04).

CONCLUSIONS

The rebamipide solution appeared to promote both the speed and quality of healing of ESD-induced ulcers by suppressing fibrosis.

Effects of EUS-guided intratumoral injection of oligonucleotide STNM01 on tumor growth, histology, and overall survival in patients with unresectable pancreatic cancer

BACKGROUND AND AIMS

Carbohydrate sulfotransferase 15 (CHST15) promotes tumor growth and invasion and is considered to be an emergent therapeutic target for pancreatic cancer. The aim of this study was to evaluate the safety and efficacy of EUS-guided fine-needle injection (EUS-FNI) of STNM01, the double-stranded RNA oligonucleotide that specifically represses CHST15, for use in patients with pancreatic cancer.

METHODS

Six patients with unresectable pancreatic cancer, treated at Tokyo Metropolitan Geriatric Hospital, were used in this open-labeled, investigator-initiated trial. A total of 16 mL STNM01 (250 nM) was injected into the tumor through EUS-FNI. The study's primary endpoint was safety, with a secondary endpoint of tumor response 4 weeks after the initial injection. Some patients received a series of infusions as extensions. The local expression of CHST15 and overall survival (OS) were also evaluated.

RESULTS

There were no adverse events. The mean tumor diameter changed from 30.7 to 29.3 mm 4 weeks after injection. Four patients exhibited necrosis of tumor in biopsy specimens. CHST15 was highly expressed at baseline, with 2 patients showing large reductions of CHST15 at week 4. The mean OS of these 2 patients was 15 months, whereas it was 5.7 months for the other 4 patients.

CONCLUSIONS

EUS-FNI of STNM01 in pancreatic cancer is safe and feasible. The CHST15 reduction could predict tumor progression and OS. Injections of STNM01 during the beginning of treatment may reduce CHST15 and warrants further investigation.

Potential for peritoneal cancer cell seeding in endoscopic full-thickness resection for early gastric cancer

BACKGROUND AND AIMS

During endoscopic full-thickness resection (EFTR) for cancers, whether exposure of the lumen to the abdominal cavity during the procedure is acceptable is controversial because of the potential risk of tumor cell seeding. To assess the possibility of transplantation as a result of contact with tumor cells during the procedure, we prospectively investigated the ability of cancer cells to be detached by touching the tumor surface.

METHODS

In 48 patients with a single early gastric cancer resected by endoscopic submucosal dissection, stamp cytology was performed by touching the surface of the specimens to glass slides. Samples were obtained from cancerous and noncancerous areas, constituting the study and control groups, respectively. The detection rate of malignant class IV or V (C-IV/C-V) samples was investigated with Papanicolaou staining. The rate of CD44v9-positive cases, a cancer stem cell marker, was assessed in C-IV/C-V samples with immunohistochemical staining.

RESULTS

Detection rates of C-IV/C-V samples in the cancerous group (53/192 slides, 27.6%) differed significantly from those of the C-IV/C-V samples in the noncancerous group (0/96 slides, 0%). Among the 53 slides of C-IV/C-V samples in the cancerous group, CD44v9 cells were expressed in 18 slides (34.0%).

CONCLUSIONS

These data suggest that cancer cells, including cancer stem cells, in early gastric cancers are easily detached via contact with the tumor surface. In EFTR, a nonexposure approach is recommended to avoid the risk of iatrogenic cancer cell seeding via contact with and transplantation of cancer cells.

Endoscopic hand-suturing for defect closure after gastric endoscopic submucosal dissection: a pilot study in animals and in humans

Background and study aims Mucosal suturing enables reliable and optimal defect closure after endoscopic treatments. We developed and investigated the feasibility of endoscopic hand-suturing (EHS) after gastric endoscopic submucosal dissection (ESD) in porcine in vivo models and in human clinical cases. Patients and methods EHS involving continuous suturing of the mucosal layers using a through-the-scope needle-holder and absorbable barbed suture, was performed after gastric ESD in six live pigs and in eight consecutive patients. Success rates, adverse events, and suture maintenance were subsequently investigated. Results EHS was successfully completed in all six pigs and eight patients (100 %) without severe adverse events. However, at 1 week postoperatively the suture closures had not been maintained in all six porcine cases and in the first four clinical cases. In the later four clinical cases, wider and tight suturing of the mucosal edges ensured that the defects remained closed until postoperative week 4. Conclusion EHS is a feasible procedure that may facilitate secure and refined endoscopic surgeries. Mucosal closure in such cases can be maintained using firm suturing.Clinical trial number: UMIN000017125.

Accuracy of biopsy for the preoperative diagnosis of superficial nonampullary duodenal adenocarcinoma

BACKGROUND AND AIMS

Endoscopic biopsy sampling for the diagnosis of duodenal adenocarcinoma is not perfect. We investigated the accuracy of biopsy specimen diagnoses of superficial nonampullary duodenal epithelial tumors (NADETs).

METHODS

Clinicopathologic data were retrospectively reviewed for 95 superficial NADETs from 95 patients who underwent endoscopic resection. Preoperative diagnoses based on biopsy specimens were compared with histologic diagnoses of resected specimens.

RESULTS

Among the 21 lesions with biopsy specimen diagnoses of carcinoma, 12 (57.1%) were histologically diagnosed as adenomas after resection. Among the 74 lesions with biopsy specimen diagnoses of adenoma, 15 (20.3%) were histologically diagnosed as carcinomas after resection. The duodenal biopsy specimen predicted final histologic diagnoses of carcinoma with a sensitivity of 37.5% (95% CI, 18.8-59.4), specificity of 83.1% (95% CI, 72.3-91.0), accuracy of 71.6% (95% CI, 61.4-80.4), positive predictive value of 42.9% (95% CI, 21.8-66.0), and negative predictive value of 79.7% (95% CI, 68.8-88.2). Among 61 cases considered suitable for EMR, treatment modality was converted from EMR to endoscopic submucosal dissection because of the nonlifting sign in 15 cases (24.6%).

CONCLUSIONS

The accuracy of duodenal biopsy sampling was relatively low. Duodenal biopsy sampling may induce unexpected fibrosis. New endoscopic modalities that can improve preoperative diagnosis yield of NADETs are eagerly awaited.

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.

Gastric ESD may be useful as accurate staging and decision of future therapeutic strategy

Background and study aims We sometimes perform gastric endoscopic submucosal dissection (ESD) for total pathologic diagnosis when preoperative diagnosis is difficult. In the present study we analyzed the treatment outcomes and adverse events of diagnostic ESD for early gastric cancer (EGC). Patients and methods We conducted a retrospective analysis of 18 consecutive cases of EGC in 18 patients with a suspected out-of-indication diagnosis who underwent diagnostic ESD, between June 2010 and November 2014. The following parameters were examined: the average length of the longer axis of the lesion; the procedure time; the rates of en bloc resection (ER), complete en bloc resection (CER), and curative resection (CR) as treatment outcomes; and the rates of perforation, delayed bleeding, aspiration pneumonia, disease-related death, and emergency surgery as adverse events. Results The treatment outcomes were as follows: average length of the longer axis of the lesion, 27.4 ± 10.0 mm; procedure time, 87.0 ± 43.1 minutes; ER rate, 18/18 (100.0 %); CER rate, 13/18 (72.2 %); CR rate, 4/18 (22.2 %). CR rate was achieved 37.5 % for the lesions which preoperative diagnosis was more than 30 mm (> 30 mm) in diameter differentiated type with mucosal layer/submucosal layer 1 invasion and ulceration positive. The adverse events (AEs) were perforation in 1 of 18 (5.5 %) patients and delayed bleeding in 1 of 18 (5.5 %). There were no other AEs. Conclusions Diagnostic ESD may be acceptable for future therapeutic strategy when we unconfirmed the pre ESD diagnosis because of lower rate of adverse events and high rate of ER.

Endoscopic slip-knot clip suturing method: prospective pilot study (with video)

BACKGROUND AND AIMS

We developed a suturing method with a slip-knot string and clips for a single-channel endoscope. The feasibility of the slip-knot clip suturing method was evaluated in this clinical pilot study.

METHODS

Ten patients underwent endoscopic submucosal dissection for colorectal and duodenal tumors 5 cm or less. A slip-knot loop can be tightened when tension is applied to the free end of the string. A clip and string can be passed through an instrument channel (3.2 mm) of a single-channel endoscope. The slip-knot loop is anchored onto the mucosal defect's proximal margin with the clip. Additional clips anchoring the slip-knot loop are placed at the opposite side of the margin. The slip-knot loop is tightened by pulling the string. Additional clips are placed to achieve complete closure.

RESULTS

The mean size of resected specimen was 34.4 ± 10.0 mm. The success rate of the slip-knot clip suturing method was 90% (9/10). In the first patient, the string was cut because of friction, and the patient dropped out of the study. After the failure of the first patient, we used wet string to reduce friction, and slip-knot string worked effectively. The mean procedure time was 18.2 ± 3.3 minutes.

CONCLUSION

The slip-knot clip suturing method could close large mucosal defects completely using a single-channel endoscope. (Clinical trial registration number: UMIN000017583.).

Laparoscopy-assisted endoscopic full-thickness resection of gastric subepithelial tumors using a nonexposure technique

Background and study aims: To avoid bacterial contamination and tumor seeding during gastrectomy surgery, we developed a nonexposure technique for endoscopic full-thickness resection with laparoscopic assistance. The feasibility and safety of nonexposed endoscopic wall-inversion surgery (NEWS) for gastric subepithelial tumors (SETs) were investigated. Patients and methods: For protruding gastric SETs ≤ 3 cm in diameter, NEWS was performed in the following sequence: laparoscopic seromuscular incision after endoscopic submucosal injection, laparoscopic seromuscular suturing with the lesion inverted, endoscopic mucosal and submucosal incision, and transoral retrieval. Technical outcomes and postoperative courses were investigated. Results: In all 20 consecutive cases, including six SETs with ulceration, NEWS was completed (mean procedural time, 213.5 minutes) without severe intraoperative or postoperative adverse events. R0 resection and perforation rates were 100 % and 5.0 %, respectively. During the mean observational period of 10.1 months, all patients survived without recurrence or apparent discomfort during food intake. Conclusion: NEWS for gastric SETs was feasible and safe and represents a useful option for minimally invasive local resection even in cases of SETs with ulceration or cancers.

A novel fully synthetic and self-assembled peptide solution for endoscopic submucosal dissection-induced ulcer in the stomach

BACKGROUND AND AIMS

Endoscopic submucosal dissection (ESD) can remove early stage GI tumors of various sizes en bloc; however, success requires reducing the relatively high postprocedure bleeding rate. The aim of this study was to assess the safety and efficacy of a novel, fully synthetic, and self-assembled peptide solution that functions as an extracellular matrix scaffold material to facilitate reconstruction of normal tissues in ESD-induced ulcers.

METHODS

Consecutive patients who underwent gastric ESD were prospectively enrolled. Immediately after the resection, the solution was applied to the site with a catheter. Gastric ulcers were evaluated by endoscopy and classified as active, healing, or scarring stages at weeks 1, 4, and 8 after ESD.

RESULTS

Forty-seven patients with 53 lesions, including 14 (29.8%) previously on antithrombotic therapy and 2 (4.3%) requiring heparin bridge therapy, were analyzed; 2 patients were excluded, 1 with perforations and 1 with persistent coagulopathy. The mean size of the en bloc resected specimens was 36.5 ± 11.3 mm. The rate of post-ESD bleeding was 2.0% (1/51; 95% CI, 0.03-10.3). Transitional rate to the healing stage of ESD-induced ulcers at week 1 was 96% (49/51). Subsequent endoscopies demonstrated the scarring stage in 19% (9/48) and 98% (41/42) at weeks 4 and 8, respectively. No adverse effects related to this solution occurred.

CONCLUSIONS

The use of this novel peptide solution may potentially aid in reducing the delayed bleeding rate by promoting mucosal regeneration and speed of ulcer healing after large endoscopic resections in the stomach. Further studies, particularly randomized controlled studies, are needed to fully evaluate its efficacy. (

CLINICAL TRIAL REGISTRATION NUMBER

000011548.).

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.

Which part of a porcine stomach is suitable as an animal training model for gastric endoscopic submucosal dissection?

BACKGROUND AND STUDY AIMS

Training using an animal model is generally recommended before performing endoscopic submucosal dissection (ESD) in humans. This study aimed to clarify the suitability of an isolated porcine stomach as an animal training model for gastric ESD.

MATERIALS AND METHODS

Study 1: six experienced endoscopists performed ESDs of six simulated lesions located in six locations in an isolated porcine stomach (1, lower third [L]/ greater curvature [Gre]; 2, L/ anterior wall [Ant]; 3, L/ posterior wall [Post]; 4, upper third [U]/ Gre; 5, U/Ant; 6, U/Post). The procedure times (s/cm(2)) were compared among the different lesion locations. A questionnaire (scored 1 - 5) completed by the endoscopists was used to assess the difference in the difficulty compared to the human stomach of the three steps of the ESD procedure (injection, incision and dissection). Study 2: the thicknesses of the mucosal layers were histologically evaluated among the six locations in three porcine and two human stomachs.

RESULTS

Study 1: the procedure speed was significantly slower at L/Gre and U/Gre in the porcine stomachs (P = 0.0004). The questionnaire responses revealed a tendency toward similarity between the lower regions of the human and porcine stomachs at L/Ant, L/Post, U/Ant and U/Post during the dissection step (P = 0.056). In contrast, the injection and incision steps at L/Gre in the porcine stomach were shown to differ in difficultly level (both P = 0.0006). Study 2: the mucosal layers in the porcine stomachs were significantly thicker than those in the human stomachs in the lower areas, especially L/Gre.

CONCLUSIONS

The difficulty of ESD and the histological features of the porcine stomachs were coincident with those of the human stomachs at L/Ant, L/Post, U/Ant and U/Post. These parts of the porcine stomach may be suitable as animal training models for gastric ESD.

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.

Estimation of subepithelial lateral extent in submucosal early gastric cancer: retrospective histological analysis

BACKGROUND

Endoscopic full-thickness resection (EFTR) is expected to make possible minimally invasive local resection of early gastric cancer (EGC). However, no consensus exists regarding how far an optimal safety margin should be set in determining the resection area by endoscopy. We aimed to investigate the optimal lateral margin of EGC which could be a candidate for EFTR by measuring the subepithelial extent (SE) of tumors.

METHODS

In 60 surgically resected submucosal EGCs 4 cm or smaller, 595 prepared slides which showed lateral tumor borders both on the epithelial surface and on the subepithelial layer were assessed. The distance between the epithelial and the subepithelial tumor edge was measured under microscopic observation, followed by analyses of the relationship between the measured SE and the histological characteristics.

RESULTS

The average and the median SE were 1.1 mm (standard deviation 1.8 mm) and 0.3 mm (range 0-12.3 mm), respectively. The 99th percentile was 8.8 mm. With regard to the histological type, the median SE was significantly greater in diffuse-type tumor than in intestinal-type tumor (0.9 mm vs 0 mm, p < 0.0001). With regard to the location of the subepithelilal tumor edge, the median SE was significantly greater in the submucosal layer than in the mucosal layer (2.6 mm vs 0.3 mm, p < 0.0001).

CONCLUSIONS

In most lesions, the SE was less than 1 cm. A safety margin may be set at 1 cm in EFTR of submucosal EGC.

Effects of carbon dioxide insufflation in balloon-assisted enteroscopy: A systematic review and meta-analysis

BACKGROUND AND AIM

The efficacy of CO2 insufflation during balloon-assisted enteroscopy remains controversial. This study aimed to perform a systematic review with meta-analysis of randomized controlled trials (RCTs) in which CO2 insufflation was compared with air insufflation in balloon-assisted enteroscopy.

METHODS

PubMed, the Cochrane library, and the Igaku-Chuo-Zasshi database were searched to identify RCTs eligible for inclusion in the systematic review. Data from the eligible studies were combined to calculate the pooled odds ratios (ORs) or weighted mean differences (WMDs) with 95% confidence intervals (CIs).

RESULTS

Four RCTs (461 patients) were identified. Compared with air insufflation, CO2 insufflation significantly increased intubation depth of oral enteroscopy (WMD: 55.2, 95% CI: 10.77-99.65, p = 0.015). However, there was significant heterogeneity. The intubation depth of anal enteroscopy showed no significant difference between the CO2 group and the air group. CO2 insufflation significantly reduced abdominal pain compared with air insufflation (WMD: -2.463, 95% CI: -4.452 to -0.474, p = 0.015), without significant heterogeneity. The PaCO2 or end-tidal CO2 level showed no significant difference between the CO2 group and air group.

CONCLUSIONS

Compared with air insufflation, CO2 insufflation during balloon-assisted enteroscopy caused less post-procedural pain without CO2 retention.

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.

Feasibility of non-exposed endoscopic wall-inversion surgery with sentinel node basin dissection as a new surgical method for early gastric cancer: a porcine survival study

Non-exposed endoscopic wall-inversion surgery (NEWS) has been developed as an endoscopic full-thickness resection technique without translumenal communication to avoid intraabdominal infection or tumor seeding. We aimed to investigate the feasibility and safety of NEWS with sentinel node basin dissection (SNBD), which can minimize the area of lymphadenectomy for early gastric cancer (EGC), in 10 porcine survival models. After placing laparoscopic ports and making markings on both the mucosal and serosal sides of a simulated lesion, indocyanine green fluid was endoscopically injected into the submucosa at 4 quadrants around the lesion. An SN basin including the stained SNs was dissected, and a circumferential sero-muscular incision around the lesion and sero-muscular suturing were performed laparoscopically, with the lesion inverted toward the inside of the stomach. Finally, circumferential mucosal incision and transoral retrieval were made endoscopically. In all cases, the lesion was resected in an en bloc fashion, and all pigs survived without adverse events. After 1 week of observation, pigs were sacrificed for macroscopic investigation. The average procedural duration was 170 min (range 130-253 min). Intraoperative perforation occurred in 1 case, which could be safely treated by laparoscopic suturing. The number of dissected SN basins was 1 in 9 cases and 2 in 1 case. Necropsy revealed no signs of severe complication. This animal survival study demonstrated that NEWS with SNBD was safe and feasible. It may provide patients with possibly node-positive EGC a minimally-sized local resection and minimally-ranged lymphadenectomy without the risk of tumor dissemination.

First case of non-exposed endoscopic wall-inversion surgery with sentinel node basin dissection for early gastric cancer

INTRODUCTION

Non-exposed endoscopic wall-inversion surgery (NEWS) is a novel technique of endoscopic full-thickness resection without transluminal access mainly designed to treat gastric cancer. Here, we report a successful case of NEWS with sentinel node basin dissection (SNBD) for early gastric cancer (EGC) with the risk of lymph node metastasis.

PATIENT AND METHODS

A 55-year-old female patient with a 2-cm, diffuse-type intramucosal EGC with ulceration was referred to our hospital for a less invasive gastrectomy based on sentinel node navigation surgery. After obtaining informed consent, NEWS with SNBD was applied. After placing mucosal markings, indocyanine green solution was injected endoscopically into the submucosa around the lesion to examine sentinel nodes (SNs). The SN basin (the area of the left gastric artery), including three stained SNs(#3), was dissected, and an intraoperative pathological diagnosis confirmed that no metastasis had occurred. Subsequently, NEWS was performed for the primary lesion. Serosal markings were placed laparoscopically, submucosal injection was added endoscopically, and circumferential sero-muscular incision and suturing were performed laparoscopically, with the lesion inverted toward the inside of the stomach. Finally, the circumferential mucosal incision was performed, and the lesion was retrieved perorally.

RESULTS

The operation was finished in 270 min without complications. The patient was uneventfully discharged 10 days after the procedure. The final pathological diagnosis was coincident with the pre- and intraoperative assessment.

CONCLUSIONS

We demonstrated the feasibility and safety of NEWS with SNBD with a favorable result. This surgical concept is expected to become a promising, minimally invasive, function-preserving surgery to cure cases of EGC that are possibly node-positive.

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.