Masahiro Asaka

Hokkaido University | Hokudai · School of Medicine

Background Several reports suggest that the microbiome of the digestive system affects vaccine efficacy and that the severity of coronavirus disease (COVID-19) is associated with decreased diversity of the oral and/or intestinal microbiome. The present study examined the effects of a severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) mRNA...

Background/aim: Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) has been affecting Hokkaido, Japan since late February 2020 until present. The aim of this study was to report the relationship between anti-SARS-CoV-2 antibody-positive and SARS-CoV-2 PCR-positive cases by analyzing anti-SARS-CoV-2 antibodies (IgG and total-Ig). Patient...

Although epidemiological studies have shown a relationship between periodontal disease and pancreatic cancer, the molecular mechanisms involved remain unclear. In this study, the effects of systemic administration of Porphyromonas gingivalis lipopolysaccharide (PG-LPS) on gene expression were comprehensively explored in mouse pancreas that did not...

We investigated the positive detection rates for hepatitis B surface antigens (HBsAg) and hepatitis C (HCV) antibodies as well as the elevation of AST and ALT in patients who were to undergo oral surgery. Our results revealed positive rates of 1.1% and 1.5% for HBsAgs and HCV antibodies, respectively. Patients older than 40 years had a higher propo...

In February 2013, Japan became the first country in the world to cover H. pylori eradication for chronic gastritis under its National Health Insurance (NHI) system. Now that eradication therapy is covered by NHI, its usage has increased dramatically, and gastric cancer deaths begin to decrease. We conducted a detailed epidemiological analysis to in...

Background: Helicobacter pylori (H. pylori) gastritis could cause dyspepsia, and eradication is recommended as the first-line treatment. Patients who continuously have their symptoms under control > 6 months after eradication are defined as having H. pylori-associated dyspepsia (HPD), whereas patients who do not benefit from successful eradication...

The annual number of deaths from gastric cancer is approximately 50,000, and there has been no change over the last 50 years in Japan. All efforts have been directed toward improving the detection of early gastric cancer by barium X-ray and endoscopy, since early cancer has a good prognosis, resulting in Japan having the best diagnostic capability...

Hypersensitivity to Helicobacter pylori, a bacterium in the stomach, is induced during eradication therapy, resulting in skin manifestations. extracellular vesicles-mediated antigen presentation could play a role in this process.

AIM To perform automatic gastric cancer risk classification using photofluorography for realizing effective mass screening as a preliminary study. METHODS We used data for 2100 subjects including X-ray images, pepsinogen I and II levels, PGI/PGII ratio, Helicobacter pylori (H. pylori) antibody, H. pylori eradication history and interview sheets. We...

Background: In Japan, there have been approximately 50 000 deaths from gastric cancer annually for over 40 years with little variation. It has been reported that most gastric cancers in Japan are caused by Helicobacter pylori infection. H. pylori eradication therapy was approved for patients with chronic gastritis by the Japanese national health i...

RNA-binding motif 5 is a putative tumor suppressor gene that modulates cell cycle arrest and apoptosis. We recently demonstrated that RNA-binding motif 5 inhibits cell growth through the p53 pathway. This study evaluated the clinical significance of RNA-binding motif 5 expression in gastric cancer and the effects of altered RNA-binding motif 5 expr...

Background and aims: Endoscopic submucosal dissection (ESD) for esophageal cancer often causes postoperative stricture when more than three-quarters of the circumference of the esophagus is dissected. Mesenchymal stem cells are a valuable cell source in regenerative medicine, and conditioned medium (CM) obtained from mesenchymal stem cells reporte...

Two men, 48 and 54 years of age, were referred for medical checkups without any particular symptoms. Upper gastrointestinal endoscopy showed a normal gastric body, but white marbled appearance in the lesser curvature of the gastric angle and antrum. Biopsy specimens revealed relatively long and tightly coiled organisms. The two patients were diagno...

Aryl hydrocarbon receptor (AHR) is a ligand-activated transcription factor that mediates the toxic activity of many environmental xenobiotics. However, its role in innate immune responses during viral infection is not fully understood. Here we demonstrate that constitutive AHR signaling negatively regulates the type I interferon (IFN-I) response du...

Purpose: Cancer-initiating cells (CICs) are thought to be essential for tumor maintenance, recurrence and distant metastasis, and they are therefore reasonable targets for cancer therapy. Cancer immunotherapy is a novel approach to target cancer. In this study, we aimed to establish novel CIC-targeting immunotherapy. Experimental design: Colorec...

The transcription factor hypoxia-inducible factor-1 (HIF-1) functions as a master regulator of hypoxic response by inducing the transcription of various genes responsible for cellular adaptation to hypoxia. In this study, we investigated the effects of protein inhibitor of activated STAT3 (PIAS3), a small ubiquitin-related modifier (SUMO) E3 ligase...

Helicobacter pylori eradication therapy for chronic gastritis achieved world-first coverage by the Japanese national health insurance scheme in 2013, making a dramatic decrease of gastric cancer-related deaths more realistic. Combining H pylori eradication therapy with endoscopic surveillance can prevent the development of gastric cancer. Even if i...

To present results of the Kyoto Global Consensus Meeting, which was convened to develop global consensus on (1) classification of chronic gastritis and duodenitis, (2) clinical distinction of dyspepsia caused by Helicobacter pylori from functional dyspepsia, (3) appropriate diagnostic assessment of gastritis and (4) when, whom and how to treat H. p...

The American Journal of Gastroenterology is published by Nature Publishing Group (NPG) on behalf of the American College of Gastroenterology (ACG). Ranked the #1 clinical journal covering gastroenterology and hepatology*, The American Journal of Gastroenterology (AJG) provides practical and professional support for clinicians dealing with the gastr...

The development process for syringolin A analogues having improved proteasome inhibitory and antitumor activity is described. The strategy was to first establish a convergent synthesis of syringolin A using a rare intramolecular Ugi three-component reaction in the last stage of the synthesis, so as to gain access toa set of structure-based analogue...

In Japan, efforts have been directed toward improving the detection of early gastric cancer by double contrast radiography and endoscopy, since early cancer has a good prognosis, resulting in Japan having the world's best diagnostic system for early gastric cancer. The 5-year survival rate of gastric cancer patients in Japan is much higher than in...

It remains unclear whether or not human intestinal spirochetosis (HIS) has any associated symptoms or lesions. In this study, we assessed the prevalence of HIS in sessile serrated adenomas/polyps (SSA/Ps) and their possible association. Following identification of early cecal cancer with SSA/P accompanied by a colonization of HIS, we went on to con...

The objectives are to find a substance or a composition capable of promoting the production of ghrelin with physiological activities such as growth hormone secretion effect, and to provide a pharmaceutical comprising it as the active ingredient. The pharmaceutical is a ghrelin production promoter comprising Rikkunshi-to as the active ingredient.

Background and AimIt was previously reported that high-grade intraepithelial neoplasia of the esophagus turns pink within a few minutes after iodine staining (pink-color sign; PCS); however, iodine staining is uncomfortable. By using narrow band imaging (NBI), color change in the area between the intraepithelial papillary capillary loop (background...

The aim of this study was to establish cancer stem-like cells /cancer-initiating cells (CSC/CICs)-targeting immunotherapy. CSCs/CICs are thought to be essential for tumor maintenance, recurrence and distant metastasis. They are therefore reasonable targets for cancer therapy. In this study, we found that a heat shock protein (HSP) 40 family member,...

In Japan, the annual number of deaths from gastric cancer is approximately 50,000 and there has been no change over the last 50 years. So far, all efforts have been directed toward improving the detection of early gastric cancer by barium X-ray and endoscopy, since early cancer has a good prognosis, resulting in Japan having the best diagnostic cap...

Heat shock factor 1 (HSF1), a major transactivator of stress responses, has been implicated in carcinogenesis in various organs. However, little is known about the biological functions of HSF1 in the development of hepatocellular carcinoma (HCC). To clarify the functional role of HSF1 in HCC, we established HSF1-knockdown KYN2 HCC cells by stably e...

Solid-pseudopapillary neoplasms (SPN) are rare pancreatic tumors. The etiology of SPN involves mutations in the gene that encodes β-catenin (CTNNB1). We herein report the case of a 23-year-old woman with a large SPN with proliferating tumor cells that displayed both solid and pseudo-papillary patterns. The simultaneous nuclear accumulation and loss...

Anorexia is an important issue in the management of elderly patients with cancer because it contributes to the development of malnutrition, increases morbidity and mortality, and negatively affects patients' quality of life. This review summarizes the potential mechanisms of the development of anorexia in three animal models that mimic the situatio...

Almost all gastric cancers including intestinal type and diffuse type develop from background of H. pylori infection of the gastric mucosa. In treatment of gastric cancer, the development of endoscopic technique expanded the indication of endoscopic treatment for early gastric cancer. Residual cancers due to incomplete resection occur within two ye...

CD133 is a cellular surface protein that has been reported to be a cancer stem cell marker, and thus it is considered to be a potential target for cancer treatment. However, the mechanism regulating CD133 expression is not yet understood. In this study, we analyzed the activity of five putative promoters (P1-P5) of CD133 in human embryonic kidney (...

TO THE EDITOR: This is a rare case report of fungemia caused by Trichosporon dermatis in a patient with refractory Burkitt's leukemia who was administered prophylactic voriconazole. Trichosporon species may be normal flora in the gastrointestinal tract and transiently colonize the skin and respiratory tracts in humans [1]. Invasive infection cause...

BACKGROUND: Recently, some patients have been found to have superficial squamous cell carcinoma (SCC) of the head and neck region during GI endoscopy; however, endoscopic biopsy from a lesion in the head and neck region is troublesome. An endocytoscopy system has been reported to enable optical biopsy of an esophageal lesion. OBJECTIVE: To evaluate...

This study was conducted to clarify the role of serotonin (5-hydroxytryptamine, 5-HT) 2C receptor (5-HT2CR) signaling during novelty-induced hypophagia in aged mice. Male C57BL/6J mice [6-week-old (young) and 79-80-week-old (aged) mice] were exposed to a novel environment, and its effects on feeding behavior, stress hormones, and appetite-related f...

We explore a strategy for the elimination of gastric cancer deaths in Japan. Most gastric cancer is due to H. pylori infection in Japan. The effect of H. pylori eradication therapy on gastric cancer prevention in younger people is excellent, but it declines along with advancing age. Therefore, a test‐and‐treat approach to H. pylori infection is rec...

Background: Pancreatic ductal carcinoma (PDC) is one of the most lethal human carcinomas. Expression patterns of some genes may predict gemcitabine (GEM) treatment efficacy. We examined predictive indicators of survival in GEM-treated patients by quantifying the expression of several genes in pre-treatment endoscopic ultrasound-guided fine-needle a...

Endoscopic resection (ER) has been widely accepted as an effective and minimally invasive treatment for patients with superficial esophageal squamous cell carcinoma (SCC). Techniques of conventional endoscopic mucosal resection (EMR) were first developed for ER. There are three representative methods of conventional EMR: endoscopic esophageal mucos...

Background: Indisetron is a serotonin (5-hydroxytryptamine type 3) receptor antagonist that also antagonizes 5-hydroxytryptamine type 4 receptors. We designed a pilot study in order to explore the optimal dosing period for indisetron during modified FOLFOX6 (mFOLFOX6). Patients and methods: Forty-two chemotherapy-naive patients with advanced col...

Background: Functional dyspepsia (FD) is a heterogeneous disease characterized by various upper abdominal symptoms. The major mechanism of FD includes impaired fundic accommodation, delayed gastric emptying and visceral hypersensitivity. We developed a novel drinking-ultrasonography test to combine a drink test with ultrasonography to assess gastr...

Backgrounds: The present study sought to establish a standard third-line eradication regimen for Helicobacter pylori in Japan. Methods: Subjects were 204 patients with H. pylori infection in whom the standard Japanese first- and second-line eradication therapies had proven unsuccessful. Patients were randomly assigned to one of the following thi...

DNA methyltransferase 1 (Dnmt1) is essential for the maintenance of hematopoietic and somatic stem cells in mice; however, its roles in human cancer stem-like cells (CSCs)/cancer-initiating cells (CICs) are still elusive. In the present study, we investigated DNMT1 functions in the maintenance of human colon CSCs/CICs using the human colon cancer c...

AMP-activated protein kinase (AMPK) is a hetero-trimeric Ser/Thr kinase composed of a catalytic α subunit and regulatory β and γ subunits; it functions as an energy sensor that controls cellular energy homeostasis. In response to an increased cellular AMP/ATP ratio, AMPK is activated by phosphorylation at Thr172 in the α-subunit by upstream AMPK ki...

H. pylori is a definite carcinogen of gastric cancer. Animal studies have revealed that primary prevention of gastric cancer by H. pylori eradication is more effective as the duration between H. pylori infection and H. pylori eradication is decreased. In human, the cohort studies showed H. pylori eradication reduced the incidence of gastric cancer...

H. pylori infection plays a important role in gastric carcinogenesis. Japanese randomized controlled study has proved that H. pylori eradication has a preventive effect for the development of gastric cancer. However, gastric cancer is sometimes detected after successful eradication of H. pylori. There is a lack of study about gastric cancers detect...

A mass screening program using photofluorography has been used as a secondary prophylaxis of gastric cancer in Japan. However, we are at a turning point for reconsidering the strategy of gastric cancer prevention because of various problems with photofluorography. The shift from current secondary prophylaxis to primary prophylaxis is now required....

Rikkunshito is a kampo herbal medicine which is widely used in Japan for the treatment of the upper gastrointestinal symptoms of patients with functional dyspepsia, gastroesophageal reflux disease, dyspeptic symptoms of postgastrointestinal surgery patients, and chemotherapy-induced dyspepsia in cancer patients. Recently, very unique characteristic...

To investigate the role of inhibitory natural killer receptors (iNKRs) in inflammatory bowel disease (IBD), we analyzed the expression of NKG2A, one of the iNKRs, on T cells in a mouse colitis model and human IBD. During the active phase of dextran sulfate sodium (DSS)-induced mouse colitis, the frequency of NKG2A+ T cells was significantly decreas...

Background and aim: Colonoscopy has the disadvantage of pain and discomfort for patients. It has been shown in randomized controlled trials that carbon dioxide (CO(2) ) insufflations significantly reduce pain and discomfort in patients undergoing colonoscopy. However, there have been no studies in which CO(2) insufflation in colonoscopy of patient...

Rikkunshito is a kampo herbal medicine which is widely used in Japan for the treatment of the upper gastrointestinal symptoms of patients with functional dyspepsia (FD), gastroesophageal reflux disease (GERD), dyspeptic symptoms of postgastrointestinal surgery patients, and chemotherapy-induced dyspepsia in cancer patients. Recently, very unique ch...

Compared with surgery, endoscopic treatment is safe and highly effective for a postoperative hilar benign bile duct stricture (BDS). However, the long-term outcome of conventional placement of a single biliary stent for hilar benign BDS is generally poor. Although the placement of multiple biliary stents is preferred, multiple stenting in a BDS is...

Gastroesophageal reflux disease (GERD) is often associated with decreased upper gastrointestinal motility, and ghrelin is an appetite-stimulating hormone known to increase gastrointestinal motility. We investigated whether ghrelin signaling is impaired in rats with GERD and studied its involvement in upper gastrointestinal motility. GERD was induce...

Background An inosine triphosphatase (ITPA) single-nucleotide polymorphism (SNP) is associated with anemia induced by pegylated interferon and ribavirin (RBV) combination therapy in patients with chronic hepatitis C (CHC). However, there are very few reports on the hematological effects of RBV monotherapy. Here, hematological changes were monitored...

Low-dose lansoprazole has not been intensively evaluated for its efficacy in the prevention of recurrent gastric or duodenal ulcers in patients receiving long-term non-steroidal anti-inflammatory drug (NSAID) therapy for pain relief in such diseases as rheumatoid arthritis, osteoarthritis, and low back pain. This multi-center, prospective, double-b...