Daisuke Obata

The Effects of Switching to Vonoprazan, a Novel Potassium-Competitive Acid Blocker, on Gastric Acidity and Reflux Patterns in Patients with Erosive Esophagitis Refractory to Proton Pump Inhibitors

Background/Aim: The effects of vonoprazan and proton pump inhibitors (PPIs) in patients with reflux esophagitis (RE) have not yet been compared using multichannel intraluminal impedance-pH (MII-pH). Methods: A total of 8 patients with persistent gastric mucosal injury, despite completing an 8-week standard PPI therapy, were enrolled in the study. While they were on standard PPI therapy, the baseline values of reflux parameters, holding time ratio (HTR) of gastric pH >4, and esophageal pH <4 were obtained by using 24 h MII-pH monitoring. They were re-evaluated after discontinuation of the therapy and 4 weeks of subsequent treatment with vonoprazan 20 mg/day. Results: The patients were found to be CYP2C19 extensive metabolizers and negative for Helicobacter pylori infection. In 7 patients (87.5%), the mucosal lesions had healed completely after vonoprazan therapy. A significant increase in gastric pH >4 HTR was observed, from 26.5 to 78.0% (p = 0.029). A reduction in esophageal pH <4 HTR was also observed but it was not statistically significant. Furthermore, acid clearance time and the total number of reflux events, including acid and proximal reflux events, were significantly reduced. Conclusion: Vonoprazan may be a better therapy for the treatment of patients with PPI-refractory RE.

CLINICOPATHOLOGICAL CHARACTERISTICS OF ABNORMAL MICRO‐LESIONS AT THE ORO‐HYPOPHARYNX DETECTED BY A MAGNIFYING NARROW BAND IMAGING SYSTEM

Background:  Narrow band imaging (NBI) with magnifying endoscopy (NBI‐ME) allows the detection of abnormal micro‐lesions smaller than 5 mm in diameter in the oro‐hypopharynx that could not be visualized previously. The purpose of the present study was to clarify the clinicopathological characteristics of abnormal micro‐lesions of the oro‐hypopharynx detected by NBI‐ME

Endoscopic submucosal dissection using a carbon dioxide laser with submucosally injected laser absorber solution (porcine model)

BackgroundRecently, endoscopic submucosal dissection (ESD) has been performed to treat early gastric cancer. The en bloc resection rate of ESD has been reported to be higher than that of conventional endoscopic mucosal resection (EMR), and ESD can resect larger lesions than EMR. However, ESD displays a higher complication rate than conventional EMR. Therefore, the development of devices that would increase the safety of ESD is desired. Lasers have been extensively studied as a possible alternative to electrosurgical tools. However, laser by itself easily resulted in perforation upon irradiation of the gastrointestinal tract. We hypothesized that performing ESD using a CO2 laser with a submucosal laser absorber could be a safe and simple treatment for early gastric cancer. To provide proof of concept regarding the feasibility of ESD using a CO2 laser with submucosally injected laser absorber solution, an experimental study in ex vivo and in vivo porcine models was performed.MethodsFive endoscopic experimental procedures using a carbon dioxide (CO2) laser were performed in a resected porcine stomach. In addition, three endoscopic experimental procedures using a CO2 laser were performed in living pigs.ResultsIn the ex vivo study, en bloc resections were all achieved without perforation and muscular damage. In addition, histological evaluations could be performed in all of the resected specimens. In the in vivo study, en bloc resections were achieved without perforation and muscular damage, and uncontrollable hemorrhage did not occur during the procedures.ConclusionsEndoscopic submucosal dissection using a CO2 laser with a submucosal laser absorber is a feasible and safe method for the treatment of early gastric cancer.

Depressed type of inflammatory fibroid polyp of the colon

Dear Editor: A 45-year-old man, who has been suffering from recurrent diarrhea and constipation, was referred to our hospital. Colonoscopy showed a reddened depressed lesion with marginal elevation in the transverse colon, near the hepatic flexure. After the mucosal surface was sprayed with indigo carmine or crystal violet dye, magnifying endoscopy revealed a type VI pit pattern of the Kudo’s classif ication in the central depression and a type I pit pattern in the surrounding area. Endoscopic ultrasonography showed that the lesion was inf iltrating into the submucosal layer. Therefore, we considered that the lesion might be a submucosal invasive colon cancer presenting like a submucosal tumor, although the biopsy specimen taken from the lesion did not contain distinct malignant components. Since we could not deny that the lesion was a malignant tumor, laparoscopy-assisted right hemicolectomy was performed. The resected specimen measured 18×18 mm in size. Zoom stereomicroscopy of the resected specimen demonstrated a type VN pit pattern in the part of the central depression, a type VI pit pattern in the rest area of the central depression, and a type I pattern in the surrounded area. Histological examination showed an enormous proliferation in the connective tissues and infiltration of eosinophils mainly in the submucosa. There were thickwalled vessels surrounded by the proliferative f ibromuscular f ibers, resulting in onion skin appearances. These f indings were compatible with inflammatory f ibroid polyp. The term “inflammatory f ibroid polyp” was introduced by Helwig and Rainer in 1953. Its etiology, suggested to be the involvement of inflammatory mechanisms or reactive responses, remains unclear. It usually forms a pedunculated or subpedunculated submucosal tumor, with erosion or ulceration overlying the mucosa. The lesions are solitary and occur predominantly in the stomach, small intestine, and rarely in the colon. Because it is usually located in the base mucosa and submucosa, diff iculty in obtaining a histological diagnosis before treatment was reported. Magnifying colonoscopy with chromoendoscopy was reported to be useful in differentiating almost all lesions detected at colonoscopy before histological evaluation. Kudo proposed the classification of the pit patterns: types I, II, IIIL, IIIs, IV, and V. Type V is divided into two types: VI and VN. In this classification, type I corresponds to normal gland, whereas type V corresponds to cancerous gland with type VN pointing towards submucosal infiltration. In the present study, magnifying endoscopy showed a type VI pit pattern in the central depression and a type I pattern in the surrounding area. These f indings, as well as depressed type macroscopic appearance, suggested that the lesion might be a depressed colon cancer, which is thought to posses high malignant potential. Zoom stereomicroscopic f indings corresponded to the endoscopic f indings, except for a demonstration of type VN pit pattern in the part of the central depression. In this case, the area showing type VN or VI pit pattern is thought to correspond to the lesion where the surface epithelium was abraded by benign erosive inflammation. With this result, it is suggested that endoscopists should be aware, when performing endoscopic examinations, that a colonic depressed lesion presenting a type V pit pattern can be an inflammatory f ibroid polyp. Int J Colorectal Dis (2007) 22:1409 DOI 10.1007/s00384-006-0180-z

Multiple gastric ulcers caused by a rice cake as an intragastric foreign body

To the Editor: Although rice cakes are a popular Japanese food item, there have been several reports that they may cause unexpected consequences as foreign bodies in the alimentary tract.1 However, case reports on rice cakes as intragastric foreign bodies are very rare.2 Here, we report a case of multiple gastric ulcers caused by a rice cake as an intragastric foreign body. A 67-year-old man was referred to our hospital because of upper abdominal pain and melena that had lasted for 4 days. On admission, computed tomography (CT) demonstrated a highdensity material in the pyloric antrum of the stomach (Fig. 1A). Emergency upper endoscopy showed multiple gastric ulcers located in a circle in the pyloric antrum (Figs. 2A, B), and a whitish mass-like material measuring approximately 4 cm in diameter in the body of the stomach (Fig. 2C). The endoscopic finding was compatible with a rice cake, and was nothing like other foreign bodies or bezoars such as a phytobezoar, trichobezoar, or pharmacobezoar. The patient had eaten a piece of frozen rice cake cooked in a microwave oven 5 days prior to admission. We suspected that the rice cake had impacted the pyloric antrum causing gastric outlet obstruction and multiple gastric ulcers mechanically. Although we attempted to draw up the rice cake, it would not pass through the cardia. Therefore, we cut the rice cake into pieces of less than 1 cm in diameter using a semicircular snare, which allowed the pieces to pass through the pyloric ring (Fig. 2D). The patient’s symptoms resolved rapidly after this procedure. On CT the following day, no high-density material was detected in the stomach (Fig. 1B), and small pieces of rice cake were visualized as high-density materials in the small intestine and the colon. The patient was discharged on the third hospital day. Several cases of rice cakes as foreign bodies in the alimentary tract have been reported. The majority of reports are related to food-induced ileus caused by rice cakes.1 Cases related to rice cakes as intragastric foreign bodies are very rare.2 Rice cakes, of which starch is the main component, are thought to digest well. In this case, the patient, who had full dentures, swallowed a piece of rice cake without chewing well. Thus, a large piece of rice cake remained in the stomach. As the patient had developed symptoms, we attempted to remove the large piece of rice cake endoscopically. As it was difficult to draw up the rice cake, we cut it into pieces of less than 1 cm in diameter using a snare. Blunt objects less than 2 cm in diameter can pass through the pyloric ring.3 After the procedure, pieces of rice cake passed through the alimentary tract, and the patient’s symptoms resolved rapidly. It has been reported that CT is a useful procedure for detecting rice cakes as a foreign body in the alimentary tract. Rice cakes usually appear as high-density “tumors” in the alimentary tract.4 In the present case, CT was helpful to verify the locations of pieces of rice cake fragmented with the snare.

Endoluminal MR imaging of porcine gastric structure in vivo

Background and aimsRecently, several new endoscopic instruments have been developed. However, even with the full use of current modalities, the safety of endoscopic surgery is not guaranteed. Information regarding factors such as fibrosis and the blood vessels under the mucosa is very important for avoiding procedure-related complications. The aim of this study was to define the detailed anatomy of the gastric wall structure in vivo using original endoluminal radiofrequency coils for safer endoscopic therapy.MethodsSwine were used as the subjects and controlled with general anesthesia. Anatomical images were obtained with T1-weighted fast spin echo (T1FSE) and T2-weighted fast spin echo (T2FSE). Dynamic magnetic resonance (MR) angiography was also obtained with three-dimensional T1-weighted fast spoiled gradient recalled acquisition in the steady state (3D-DMRA) following the injection of hyaluronic acid sodium into the submucosal layer.ResultsPorcine gastric wall structure was visualized, and four layers were discriminated in the T1FSE and T2FSE images. The vascular structure was clearly recognized in the submucosa on 3D-DMRA.ConclusionEndoluminal MR imaging was able to visualize the porcine stomach with similar quality to endoscopic ultrasonography imaging. Additionally, it was possible to visualize the vascular structures in the submucosal layer. This is the first report to show that blood vessels under the gastric mucosa can be depicted in vivo.

Selective mucosal ablation using CO2 laser for the development of novel endoscopic submucosal dissection: comparison of continuous wave and nanosecond pulsed wave

Endoscopic submucosal dissection (ESD) is accepted as a minimally invasive treatment technique for small early gastric cancers. Procedures are carried out using some specialized electrosurgical knifes with a submucosal injection solution. However it is not widely used because its procedure is difficult. The objective of this study is to develop a novel ESD method which is safe in principle and widely used by using laser techniques. In this study, we used CO2 lasers with a wavelength of 10.6 μm for mucosal ablation. Two types of pulse, continuous wave and pulsed wave with a pulse width of 110 ns, were studied to compare their values. Porcine stomach tissues were used as a sample. Aqueous solution of sodium hyaluronate (MucoUpR) with 50 mg/ml sodium dihydrogenphosphate is injected to a submucosal layer. As a result, ablation effect by CO2 laser irradiation was stopped because submucosal injection solution completely absorbed CO2 laser energy in the invasive energy condition which perforates a muscle layer without submucosal injection solution. Mucosal ablation by the combination of CO2 Laser and a submucosal injection solution is a feasible technique for treating early gastric cancers safely because it provides a selective mucosal resection and less-invasive interaction to muscle layer.

Simple and safe replacement technique for a buried percutaneous endoscopic gastrostomy tube using a laparoscopic surgery device.

To the Editor: We read with interest the original article by Dr Fagundes and colleagues, which describes the positive correlation between minimal skin incision and a low risk of peristomal infection in percutaneous endoscopic gastrostomy (PEG).1 This advantage of minimal skin incision should also be applicable to the replacement of a buried tube in buried bumper syndrome (BBS). However, the removal of a buried tube has required skin or gastric wall incision in several reports.2,3 Herein, we describe a case of a buried PEG tube, which could be replaced with another new tube at the same site using a laparoscopic surgery device (Fig. 1) without skin incision or gastric wall incision. A 77-year-old woman received a PEG tube (Ideal button 22Fr, 4.5 cm; Olympus, Japan) 6 months earlier because of an inability to swallow owing to lower gingival cancer. She was referred to our institution for immobility of the tube. Endoscopy demonstrated that the internal bumper had become buried in the gastric wall, with the winged tips partially exposed in the gastric lumen (Fig. 2). We diagnosed this case as a partial type of BBS. After obtaining written informed consent, we attempted PEG tube replacement. Through the internal lumen of the PEG tube, an incisor device (Endosciz 5mm Hook Scissors; Covidien, Japan) was inserted into the gastric lumen (Fig. 1), and then 3 of the 4 winged tips were incised under endoscopic guidance (Fig. 2). After these procedures, the tube could simply be removed by external traction. A balloon-tipped PEG catheter (Bard gastrostomy tube 22Fr, Bard; Medicon, Japan) was inserted at the same site over a guidewire. No adverse events occurred during or after the procedures. In patients with BBS, the degree of migration of the internal bumper can be classified into 3 grades (partial, subtotal, and total BBS). The present case was diagnosed as a partial type of BBS, because the tip of the existing tube was exposed in the gastric lumen (Fig. 2). BBS is a rare (2% to 6% of PEG placements) but well-recognized complication of PEG tube placement. However, the management of BBS has not yet been standardized. Although several techniques have been described, they mostly require abdominal skin or gastric wall incision. Frascio et al2 described a method of buried tube removal after skin incision under local anesthesia. Ma et al3 described a technique of buried tube removal after