Takuma Okamura

Antimicrobial resistance and characteristics of eradication therapy of Helicobacter pylori in Japan: a multi-generational comparison.

Eradication of Helicobacter pylori (H. pylori) at a younger age is considered to be effective in preventing gastric cancer. This study assessed the characteristics of eradication therapy in young patients.

Helicobacter pylori-Negative Primary Rectal MALT Lymphoma: Complete Remission after Radiotherapy

Rectal mucosa-associated lymphoid tissue (MALT) lymphoma is a rare condition. Although the majority of patients undergo surgical resection, a definitive treatment for rectal MALT lymphoma has not yet been established. In the present study, we report the outcome of radiotherapy in 3 patients with rectal MALT lymphoma. Our cohort ranged from 56 to 65 years of age. The male/female ratio was 1:2, and all patients were in stage I (Lugano classification) of the disease. Endoscopic findings revealed elevated lesions resembling submucosal tumors in 2 patients, and a sessile elevated lesion with a nodular surface in 1 patient. One of the 3 patients underwent magnifying endoscopy with crystal violet staining that demonstrated a type I pit pattern (Kudo’s classification) lesion with a broad intervening area caused by the upthrust of the tumor from the submucosa. All patients tolerated radiotherapy at doses of 30 Gy without major complications and achieved complete remission. Follow-up ranged from 13 to 75 months (mean 51.0 months), revealing no recurrence of MALT lymphoma. As such, we propose radiotherapy to be a safe and effective means for treating rectal MALT lymphoma.

Superficially located enlarged lymphoid follicles characterise nodular gastritis

Summary Nodular gastritis is a form of chronic Helicobacter pylori gastritis affecting the gastric antrum and characterised endoscopically by the presence of small nodular lesions resembling gooseflesh. It is generally accepted that hyperplasia of lymphoid follicles histologically characterises nodular gastritis; however, quantitative analysis in support of this hypothesis has not been reported. Our goal was to determine whether nodular gastritis is characterised by lymphoid follicle hyperplasia. The number, size, and location of lymphoid follicles in nodular gastritis were determined and those properties compared to samples of atrophic gastritis. The percentages of high endothelial venule (HEV)-like vessels were also evaluated. The number of lymphoid follicles was comparable between nodular and atrophic gastritis; however, follicle size in nodular gastritis was significantly greater than that seen in atrophic gastritis. Moreover, lymphoid follicles in nodular gastritis were positioned more superficially than were those in atrophic gastritis. The percentage of MECA-79+ HEV-like vessels was greater in areas with gooseflesh-like lesions in nodular versus atrophic gastritis. Superficially located hyperplastic lymphoid follicles characterise nodular gastritis, and these follicles correspond to gooseflesh-like nodular lesions observed endoscopically. These observations suggest that MECA-79+ HEV-like vessels could play at least a partial role in the pathogenesis of nodular gastritis.

Screening to Identify and Eradicate Helicobacter pylori Infection in Teenagers in Japan

The purpose of this study was to elucidate the prevalence and effect of Helicobacter pylori infection in Japanese teenagers. The study subjects were students ages 16 to 17 from one high school studied between 2007 and 2013. Students who tested positive on this screening examination underwent esophagogastroduodenoscopy and biopsy samples to determine their H pylori status using culture and histology. Cure of H pylori infections was determined by urea breath test. The low rate of prevalence of H pylori infection in present Japanese teenagers makes it possible and cost effective to perform examinations and carry out treatment of this infection in nationwide health screenings of high school students.

A case of Helicobacter heilmannii-associated primary gastric mucosa-associated lymphoid tissue lymphoma achieving complete remission after eradication

A 46-year-old man underwent gastrointestinal endoscopy while visiting the hospital for a general physical check-up. Coarse mucosa in the antrum with superficial erosions was found by endoscopic gastrointestinal examination, but no atrophic changes were seen in the corpus. Histopathological examination of gastric biopsy specimens revealed mucosa-associated lymphoid tissue (MALT) lymphoma. Although Helicobacter pylori was not detected in our patient, H. heilmannii was identified histologically and by polymerase chain reaction analysis, resulting in the diagnosis of H. heilmannii-associated gastric MALT lymphoma. We successfully eradicated H. heilmannii and achieved complete remission of gastric MALT lymphoma by antibiotic therapy. H. heilmannii usually causes milder gastritis than H. pylori, but it has been more closely associated with MALT lymphoma. As such, when H. pylori infection is excluded in patients with gastric MALT lymphoma, physicians should next consider the possibility of H. heilmannii. Furthermore, our research suggests that eradication therapy is effective for treatment of localized H. heilmannii-associated gastric MALT lymphoma.

Reduced gland mucin‐specific O‐glycan in gastric atrophy: A possible risk factor for differentiated‐type adenocarcinoma of the stomach

O‐glycans exhibiting terminal α1,4‐linked N‐acetylglucosamine (αGlcNAc) are attached to MUC6 in gastric gland mucins and serve as a tumor suppressor for gastric adenocarcinoma. Gastric atrophy is associated with risk for gastric cancer. However, the significance of αGlcNAc expression in pyloric glands of chronic atrophic gastritis remains unknown. Here, we asked whether reduced αGlcNAc expression in chronic atrophic gastritis is associated with risk for gastric cancer.

Accuracy of Endoscopic Diagnosis for Mild Atrophic Gastritis Infected with Helicobacter pylori

Background/Aims This study examined the accuracy of endoscopic evaluation for determining the Helicobacter pylori infection status in patients with mild atrophy who might not exhibit characteristic endoscopic findings. Methods Forty endoscopists determined the H. pylori infection status of 50 randomly presented H. pylori-positive and H. pylori-negative cases on the basis of a list of established findings. Results The median clinical endoscopy experience was 7 years (range, 1–35 years), including 22 board-certified endoscopists (55%) of the Japan Gastroenterological Endoscopy Society. The mean accuracy rate of endoscopic diagnosis was 67% and was unrelated to experience status (experienced vs. trainee: 69% vs. 65%, p=0.089) and total years of experience (R2 =0.022). The most frequently selected endoscopic findings were regular arrangement of collecting venules (59%), atrophy (45%), and red streak (22%), which had fair accuracy rates of 67%, 65%, and 73%, respectively. By contrast, the accuracy rates of nodularity (89%) and mucosal swelling (77%) were highest. The 20 endoscopists who more frequently identified these findings diagnosed H. pylori infection significantly more accurately than did the other endoscopists (71% vs. 64%, p=0.008). Conclusions Careful attention to nodularity and mucosal swelling in patients with mild atrophy may enhance diagnosis, enable prompt treatment, and avoid possible long-term carcinogenesis.

A case of acquired hemophilia A diagnosed after percutaneous endoscopic gastrostomy

A 65-year-old male with no personal or familial history of bleeding disorders underwent percutaneous endoscopic gastrostomy (PEG) for neurogenic dysphagia due to subarachnoid hemorrhage. On postoperative day 6, continuous oozing of venous blood was observed at the stoma. Prothrombin time was within normal range, but activated partial thromboplastin time was prolonged. Cross-mixing test results indicated the existence of an inhibitor, and laboratory findings revealed decreased factor VIII activity and high levels of factor VIII inhibitor. The patient was diagnosed as having acquired hemophilia A, for which steroid monotherapy was effective. Acquired hemophilia A is a rare but potentially fatal disease. Clinicians should be aware of this condition in patients presenting with sudden hemorrhage after PEG or other endoscopic treatments, even in those with no apparent history of bleeding.