A novel coronavirus infection [coronavirus disease 2019 (COVID-19)] became a global epidemic just months after the first case of infection was reported in Wuhan, China in December 2019. Its spread has severely affected social systems and people's lives. In the academic world, this led to an increase in the number of papers submitted to this journal. While the number of articles submitted to the journal reached a record high in 2020, the number of articles submitted last year returned to prepandemic levels. In this article, we report on the current submission conditions, including the number of submissions and acceptance rate, as well as the citation trends of highly cited articles and those published by the journal in 2022.

Objective The risk of developing peptic ulcers and gastrointestinal bleeding is high in patients with chronic kidney disease (CKD). Whether or not kidney transplant patients, who are treated with multiple medications, including immunosuppressive drugs, are at an increased risk of developing peptic ulcers is unclear.

Methods In this retrospective study, we compared the clinical and endoscopic features of gastroduodenal ulcers between kidney transplant patients and CKD patients. The subjects underwent upper gastrointestinal endoscopy between January 2015 and March 2021.

Results Gastroduodenal ulcers were observed more frequently (6.5%) in kidney transplant patients than in CKD patients (2.1%) (p=0.026). Due in part to the lower median age in the kidney transplant ulcer group than in the CKD ulcer group (59 vs. 70 years old, p=0.016), the rates of atrophic gastritis and Helicobacter pylori infection were also lower in the kidney transplant ulcer group than in the CKD ulcer group. Significantly more kidney transplant patients were treated with acid secretion inhibitors than CKD ulcer patients (100% vs. 34.8%, p=0.0005). Peptic ulcers were observed frequently in kidney transplant patients, even though common risk factors for gastroduodenal ulcers other than immunosuppressive drugs were few. All kidney transplant patients were taking immunosuppressive medications, and tacrolimus, mycophenolate mofetil, and methylprednisolone were taken more frequently than others.

Conclusion Kidney transplant patients have a high risk of developing gastroduodenal ulcers. All kidney transplant patients take immunosuppressive medications, so there may be an association between immunosuppressive medications and gastroduodenal ulcer development.

Objective The objective of this study was to estimate the humoral immune response evaluated by immunoglobulin G (IgG) against the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) spike receptor-binding domain (RBD-IgG) following the third mRNA coronavirus disease 2019 (COVID-19) vaccination in patients with kidney disease who received immunosuppressive treatment.

Methods The primary outcome was RBD-IgG levels after the third SARS-CoV-2 vaccination. The primary comparison was the RBD-IgG levels between patients with kidney disease who received immunosuppressive treatment (n=124) and those who did not (n=33).

Results The RBD-IgG levels were significantly lower in the patients with kidney disease who received immunosuppressive treatment than in those who did not receive immunosuppressive treatment. The RBD-IgG levels were lower in patients treated with glucocorticoid monotherapy than in those who did not receive immunosuppressive treatment. Even in patients who received ≤5 mg prednisolone, the RBD-IgG levels were significantly lower. Nine of the 10 patients who received rituximab within one year before the first vaccination did not experience seroconversion after the third vaccination. Meanwhile, all nine patients who received rituximab only after the second vaccination experienced seroconversion, even if B cell recovery was insufficient. Patients treated with mycophenolate mofetil plus glucocorticoid plus belimumab had significantly lower RBD-IgG levels than those treated with mycophenolate mofetil plus glucocorticoid.

Conclusion The RBD-IgG levels were lower in patients with kidney disease who received immunosuppressive treatment than in those who did not receive immunosuppressive treatment. Low-dose glucocorticoid monotherapy affected the humoral immune response following the third mRNA COVID-19 vaccination.

Objective Calcitonin gene-related peptide (CGRP)-(receptor) monoclonal antibody (mAb) has been reported to reduce the frequency of medication overuse in patients with migraine. The present study investigated whether or not CGRP-mAb treatment shows early effectiveness for medication overuse headache (MOH) in Japan.

Methods We retrospectively reviewed 34 patients with MOH who received preventive treatment with CGRP-mAb from June 2021 to October 2022. The International Classification of Headache Disorders, 3rd edition was used to diagnose MOH. This study was conducted at the Department of Neurology, Saitama Medical University. Patients were recruited from this specialized headache outpatient center.

Results In total, 69 patients with migraine had newly introduced CGRP-mAb, and 34 patients had MOH (49.3%). The mean±standard deviation patient age was 44±15.5 years old. The study population included 24 women (70.6%). The types of CGRP-mAb used were galcanezumab in 16 patients (47.0%), fremanezumab in 10 (29.4%), and erenumab in 8 (23.5%). The mean disease duration was 19.6±13.1 years. The types of migraine diagnosis were chronic migraine in 28 patients (82.4%) and migraine with aura in 11 patients (32.4%). The mean number of headache days in the month before administration of CGRP-mAb was 22±7.7 days; 1 month after administration, the MHD was 16.9±9.1 days. The change in MHD was -5.7 days (22.7%), indicating significant improvement (p<0.05).

Conclusion CGRP-mAb has been suggested as a preventive treatment for patients with MOH. Further investigation of the long-term efficacy of CGRP-mAb for MOH is needed.

We experienced a case of treatment-resistant eosinophilic gastrointestinal disease (EGID). The patient, a 46-year-old man, presented with a fever, persistent abdominal pain, and an elevated peripheral eosinophil count. Eosinophil infiltration of the intestinal mucosa was also observed, and EGID was diagnosed. Corticosteroid therapy was initiated, but no improvement was seen. However, after mepolizumab (anti-interleukin 5 antibody) was administered, the patient's disease was controlled. Currently, the indications for mepolizumab are limited to bronchial asthma and paraneoplastic eosinophilic polyangiitis, but the experience herein reported suggests its usefulness in the treatment of EGID.

Protruded signet-ring cell carcinoma (SRCC) is extremely rare. We herein report a rare case of flat elevated gastric SRCC in a patient without Helicobacter pylori infection. Esophagogastroduodenoscopy of a woman in her 50s revealed a flat, whitish lesion in the gastric body with elevation. Histological results of an endoscopically biopsied specimen led to a diagnosis of SRCC. Resection using endoscopic submucosal dissection was performed, and histology results revealed that the tumor was localized in the lamina propria. The size was 10×6 mm, and a protrusion had been formed by SRCC enlargement without destruction of the surface epithelium structure.

Inflammatory myofibroblastic tumor (IMT) is a rare tumor composed of myofibroblasts with inflammatory blood cell infiltration. It commonly occurs in the lungs and rarely in the esophagus. We herein report a valuable case of IMT originating in the esophagus. A 60-year-old Japanese woman with dysphagia had a large subepithelial lesion in the cervical esophagus, which was 15 cm in length. Surgical resection was performed to confirm the pathological diagnosis and improve the symptoms. The postoperative diagnosis was IMT composed of multiple nodules. There was no recurrence or metastasis within one year after surgery.

Visceral aneurysms are a rare but important form of abdominal vascular disease. Rupture of the aneurysms leads to serious symptoms, such as acute abdomen or abdominal bleeding. However, duodenal obstruction due to arterial rupture of an aneurysm is very rare. We herein report a 50-year-old woman with suspected segmental arterial mediolysis (SAM) who was first diagnosed with acute abdomen and duodenal obstruction. Rupture of a pancreaticoduodenal artery aneurysm was confirmed, and she was treated with transcatheter arterial embolization. In cases of acute abdomen, SAM is a rare but important possibility to consider as a differential diagnosis.

Primary gastric rhabdomyosarcoma is extremely rare. An 87-year-old man visited our clinic with a chief complaint of abdominal pain. Computed tomography (CT) and ¹⁸F-fluorodeoxyglucose positron emission tomography-CT revealed a massive tumor originating from the muscularis propria of the stomach along with splenic vein tumor thrombosis. We diagnosed the patient with primary gastric rhabdomyosarcoma by an endoscopic ultrasound-guided fine-needle aspiration/biopsy.

We herein report a case of a branch-duct intraductal papillary mucinous neoplasm (IPMN) with rapidly developing intracystic xanthogranulomatous nodules. A unilocular cystic lesion without a mural nodule was found in the pancreatic tail of a 69-year-old man. Ten months later, multiple mural nodules emerged unexpectedly within the cyst, and the patient underwent distal pancreatectomy. Based on immunohistochemical studies and a molecular analysis, we diagnosed him with branch-duct IPMN of the gastric immunophenotype. Fragility of the pancreatic duct mucosa and consequent exposure of the wall to pancreatic juice might have caused marked granulation nodule formation in the cyst lumen.

A 66-year-old man diagnosed with immunoglobulin G4-related sclerosing cholangitis (IgG4-SC) with diffuse intrahepatic bile duct stenosis and elevated serum IgG4 levels was referred for a further examination because of elevated serum carbohydrate antigen 19-9 levels despite treatment with corticosteroids. An umbilical nodule was found on a physical examination and a biopsy showed adenocarcinoma. Although several imaging studies revealed no changes from prior studies, bile cytology collected by endoscopic retrograde cholangiopancreatography showed adenocarcinoma. Consequently, the patient was diagnosed with cholangiocarcinoma resembling IgG4-SC after detecting an umbilical metastasis, also known as Sister Mary Joseph's nodule.

Sacubitril/valsartan, a novel therapy in chronic heart failure (CHF), inhibits the breakdown of various peptides. However, whether or not sacubitril/valsartan administration affects urinary C-peptide levels is unclear. We herein report a 70-year-old man with type 2 diabetes mellitus (T2DM) and hypertension coexisting with CHF and nephrotic syndrome. The patient's urinary C-peptide levels dramatically increased after sacubitril/valsartan administration and decreased after discontinuation of the drug. Furthermore, sacubitril/valsartan administration to five other patients with hypertension and T2DM markedly increased urinary C-peptide levels. Thus, the insulin secretory capacity of patients with T2DM receiving sacubitril/valsartan may be overestimated when their urinary C-peptide level is measured.

We herein report the first case of c-ros oncogene 1 (ROS1)-rearranged advanced non-small-cell lung cancer (NSCLC) in which lung injury was induced by crizotinib and entrectinib. Crizotinib was administered as first-line chemotherapy in a woman in her early 70s with stage IV NSCLC showing ROS1 rearrangement. This resulted in the development of drug-induced organizing pneumonia, which was alleviated by discontinuing drug administration and giving corticosteroids. Following second-line chemotherapy with entrectinib, a similar lung injury was noted. In cases of crizotinib-induced lung injury, physicians must be alert for drug-induced lung injury in subsequent treatment with entrectinib.

As cases of magnesium oxide pill aspiration are rare, the associated airway proinflammatory properties and appropriate analytic strategies remain unclear. An 81-year-old woman presenting with dyspnea was diagnosed with magnesium oxide pill aspiration. Computed tomography, a "mixing test" with levodopa, and a magnesium content analysis revealed a similar density between the foreign body and her prescribed magnesium oxide pill. The patient recovered without airway complications after foreign body removal. Clinicians should be aware of magnesium oxide tablets as potential bronchial foreign bodies in elderly patients because they may not dissolve without exposure to gastric juices.

An 85-year-old woman was diagnosed with coronavirus disease 2019 (COVID-19). The patient was treated with dexamethasone, and the infection was cured. She later developed a low-grade fever and fell unconscious. Positivity for herpes simplex virus deoxyribonucleic acid polymerase chain reaction (HSV-DNA PCR) was detected in the cerebrospinal fluid, so she was diagnosed with HSV encephalitis. The patient was treated with antiviral drugs and recovered from the HSV encephalitis. This case suggests that, in patients with COVID-19 and disorders of consciousness, the possibility of HSV encephalitis should be considered along with COVID-19 encephalitis.

The prognosis of patients with post-coronavirus disease 2019 (COVID-19) interstitial lung disease remains unclear. We herein report an autopsy case in which serial progression after the onset of post-COVID-19 interstitial lung disease resulted in an acute exacerbation, leading to a fatal outcome. Autopsy findings included hyaline membrane formation/interstitial inflammatory cell infiltration, suggestive of acute lesions, and severe regional fibrosis, indicating a preexisting chronic condition. In the present case, we histopathologically confirmed the acute exacerbation of post-COVID-19 interstitial lung disease.

A 70-year-old woman with advanced endometrial cancer developed right ptosis and muscle weakness in the right quadriceps after pembrolizumab administration. Serum creatine kinase (CK) levels were elevated, and anti-striated muscle antibodies were positive. On magnetic resonance imaging, the right vastus lateral muscle showed an abnormal signal. She was diagnosed with pembrolizumab-induced myopathy. We initiated plasma exchange (PE), and the ptosis immediately resolved. We then introduced oral corticosteroids, which improved her muscle weakness. We were able to rapidly diagnose her with ocular symptoms and serum CK level elevation. The early initiation of PE might prevent the exacerbation of pembrolizumab-induced myopathy.

The differential diagnosis of myelopathy in patients with malignancies may be challenging, as a spinal biopsy is not always applicable. A 66-year-old woman who had shown transient double vision and nausea developed spasticity and impaired deep sensation in both feet. Magnetic resonance imaging showed abnormal gadolinium enhancement of the brainstem, spinal meninges, and nerve root. Cerebrospinal fluid (CSF) revealed mild pleocytosis and elevated protein and decreased glucose levels, although CSF cytology was normal. Lung carcinoma was simultaneously detected, and noncaseating granuloma was detected from the hilar and axillary lymph nodes, so she was diagnosed with sarcoid-associated myelopathy. Her symptoms were kept stable by intravenous methylprednisolone, oral prednisolone, and methotrexate. This is the first case of sarcoid-associated myelopathy accompanied by lung cancer, suggesting the importance of clinical course, repetitive CSF cytology, and a biopsy of the lymph nodes to distinguish sarcoid-associated myelopathy from meningeal metastasis in patients with malignancies.

We evaluated the pathophysiology of dysphagia considered to be induced by benzodiazepine using high-resolution manometry (HRM). A 53-year-old man with Parkinson disease had had dysphagia for over 3 months. He had been taking several benzodiazepines for more than four years. Two weeks after discontinuation of the benzodiazepines, HRM revealed increased pharyngeal contractility and residual pressure at the upper esophageal sphincter. A video-fluoroscopic swallowing study showed improved pharyngeal bolus passage. Benzodiazepine-induced dysphagia may be due to the muscle relaxant effects on the swallowing muscles and attenuation of the barrier function which prevents reflux from the esophagus into the pharynx.

The anti-GQ1b IgG antibody is often accompanied by other anti-ganglioside antibodies, which induces various neurological symptoms. We herein report a patient with anti-ganglioside antibodies, including anti-GQ1b IgG and anti-GT1a IgG antibodies, showing bilateral ophthalmoplegia, facial nerve palsies, dysarthria, dysphagia, dysesthesia in both hands, and enhancement of the bilateral oculomotor, abducens, and facial nerves on gadolinium (Gd)-enhanced T1-weighted brain magnetic resonance imaging (MRI). He was first treated with intravenous immunoglobulin, which improved ophthalmoplegia, bulbar palsies, and dysesthesia of hands, but the facial nerve palsies worsened, and Gd enhancement of the brain nerves persisted. High-dose methylprednisolone therapy subsequently improved the facial nerve palsies and Gd enhancement of the cranial nerves. This is the first case with anti-ganglioside antibodies presenting with multiple cranial nerve palsies that was followed to track the changes in the Gd enhancement of cranial nerves on MRI.

We herein report a case of anti-gamma aminobutyric acid type A receptor antibody-associated encephalitis (anti-GABA_A-RE) with progressive aphasia and generalized tonic-clonic seizures. Cerebral magnetic resonance imaging (MRI) showed cortical brain lesions coupled with hypermetabolism on fluorodeoxyglucose-positron emission tomography. After two courses of methylprednisolone pulse therapy, improvements in neurological symptoms without sequelae and the total disappearance of MRI lesions were observed. Upon encountering patients with refractory status epilepticus, multifocal cerebral MRI lesions, and suspected autoimmune encephalitis, especially in cases with thymoma, it would be prudent to suspect anti-GABA_A-RE and consider the evaluation of anti-GABA_A receptor antibody and methylprednisolone pulse therapy.

We herein report a case of myelin oligodendrocyte glycoprotein (MOG) antibody-associated disease (MOGAD) that occurred following coronavirus disease 2019 (COVID-19) vaccination and its subsequent relapse after COVID-19 infection. A 34-year-old woman developed cortical encephalitis in the right temporoparietal lobe one week after receiving the mRNA-1273 vaccine. The cerebrospinal fluid was positive for anti-MOG antibody. Her symptoms gradually improved after three courses of intravenous methylprednisolone therapy. Six months later, she experienced a relapse of transverse myelitis following COVID-19 infection. Despite treatment with plasma exchange, the patient remained paralyzed in both lower limbs. We herein review the relationship between MOGAD and COVID-19 vaccination/infection.

We herein report a rare case of periodic fever, aphthous stomatitis, pharyngitis and cervical adenitis (PFAPA) syndrome that occurred in an 18-year-old man. He visited our hospital with recurrent episodes of a fever, pharyngitis and adenitis without suggestive findings of infection. These episodes resolved within 5 days and recurred quite regularly, with an interval of about 30 days. As the febrile episodes significantly impaired his quality of life, he was treated with colchicine (0.5 mg) as prophylaxis. This completely prevented the episodes during six months of follow-up. Colchicine may therefore be effective in cases of adult-onset PFAPA syndrome.