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A 60-year-old male with cStage IVB lung cancer was treated with pembrolizumab. However, after five courses of pembrolizumab, he developed pembrolizumab-related cholangitis. Imaging studies showed enlargement and diffuse wall thickening of the gallbladder and mild dilation of the bile ducts without any obvious obstruction. As the patient experienced severe abdominal pain, we suspected bile stasis and performed biliary drainage. However, his condition did not improve, and he developed multiple liver abscesses and died during immunosuppressive therapy. Our case suggests that in ir-cholangitis, the indication and method of endoscopic retrograde cholangiopancreatography should be carefully judged.

Endoscopic submucosal dissection (ESD) for remnant gastric cancer (RGC) after distal gastrectomy (DG) is considered technically challenging due to the narrow working space, and severe fibrosis and staples from the previous surgery. Technical difficulties of ESD for RGC after DG have not been thoroughly investigated. This study aimed to develop and validate a risk-scoring system for assessing the technical difficulty of ESD for RGC after DG in a large multicenter cohort. We investigated patients who underwent ESD for RGC after DG in 10 institutions between April 2008 and March 2018. A difficult case was defined as ESD lasting ≥ 120 min, involving piecemeal resection, or the occurrence of perforation during the procedure. A risk-scoring system for the technical difficulty of the procedure was developed based on multiple logistic regression analyses, and its performance was internally validated using bootstrapping. A total of 197 consecutive patients with 201 lesions were analyzed. There were 90 and 111 difficult and non-difficult cases, respectively. The scoring model consisted of four independent risk factors and points of risk scores were assigned for each as follows: tumor size > 20 mm: 2 points; anastomosis site: 2 points; suture line: 1 point; and non-expert endoscopist: 2 points. The C-statistics of the scoring system for technical difficulty was 0.72. We developed a validated risk-scoring model for predicting the technical difficulty of ESD for RGC after DG that can contribute to its safer and more reliable performance.

AIM To investigated the hemostatic ability of the S and F1-10 methods in clinical and ex vivo studies. METHODS The hemostatic abilities of the two methods were analyzed retrospectively in all six gastric endoscopic submucosal dissection cases. The treated vessel diameter, compressed vessel frequency, and bleeding frequency after cutting the vessels were noted by the recorded videos. The coagulation mechanism of the two power settings was evaluated using the data recording program and histological examination on macro- and microscopic levels in the ex vivo experiments using porcine tissues. RESULTS F1-10 method showed a significantly better hemostatic ability for vessels ≥ 2 mm in diameter and a trend of overall better coagulation effect, evaluated by the bleeding rate after cutting the vessels. F1-10 method could sustain electrical current longer and effectively coagulate the tissue wider and deeper than the S method in the porcine model. CONCLUSION F1-10 method is suggested to achieve a stronger hemostatic effect than the S method in clinical procedures and ex vivo models.

Carcinoembryonic antigen-related cell adhesion molecule (CEACAM) 1 and CEACAM20, immunoglobulin superfamily members, are predominantly expressed in intestinal epithelial cells (IECs) and co-localized at the apical surface of these cells. We here showed that the expression of mouse CEACAM1 and CEACAM20 at both mRNA and protein levels was markedly reduced in IECs of the small intestine by the treatment of mice with antibiotics against Gram-positive bacteria. The expression of both proteins was also decreased in IECs of the small intestine from germ-free mice, compared with that from control specific-pathogen-free mice. Exposure of intestinal organoids to IFN-γ markedly increased the expression of either CEACAM1 or CEACAM20, whereas the exposure to TNF-α increased the expression of the former protein, but not that of the latter. In contrast, the expression of CEACAM20, but not of CEACAM1, in intestinal organoids was markedly increased by exposure to butyrate, a short-chain fatty acid produced by bacterial fermentation in the intestine. Collectively, our results suggest that Gram-positive bacteria promote the mRNA expression of CEACAM1 or CEACAM20 in the small intestine. Inflammatory cytokines or butyrate likely participates in such effects of commensal bacteria.

Carcinoembryonic antigen-related cell adhesion molecule (CEACAM) 20 is an immunoglobulin-superfamily transmembrane protein that contains an immunoreceptor tyrosine-based activation motif (ITAM) in its cytoplasmic region. However, the mechanism for tyrosine phosphorylation of, or the physiological function of, this protein remains largely unknown. Here we have shown that CEACAM20 is indeed tyrosine-phosphorylated by either treatment with pervanadate or forced expression of c-Src. In addition, Tyr522, Tyr559 or Tyr570, the latter two of which are within the ITAM, is likely important for such tyrosine phosphorylation. Forced expression of Myc-tagged wild-type CEACAM20 promoted the phagocytic activity of cultured cells for microbeads coupled with anti-Myc antibodies. By contrast, such phagocytic activity was markedly reduced when a mutant form of CEACAM20, in which Tyr559 and Tyr570 were substituted with phenylalanine, was expressed. Furthermore, the CEACAM20-mediated phagocytic activity was markedly prevented by the treatment with an inhibitor for either Src family kinases (SFKs), Syk, phosphoinositide 3-kinase (PI3K) or phospholipase C-γ (PLCγ). Inhibition of actin polymerization by Cytochalasin D significantly inhibited the CEACAM20-mediated phagocytosis. These results thus suggest that tyrosine phosphorylation of CEACAM20 likely promotes phagocytic activity of the cells. The CEACAM20-mediated phagocytic activity requires the activation of SFKs, Syk, PI3K or PLCγ.

Proper regulation of epithelial cell turnover is important for the structural integrity and homeostasis of various tissues, including the intestine. Here we show that ablation of Csk, a negative regulator of Src family kinases (SFKs), specifically in intestinal epithelial cells (IECs) resulted in the development of hyperplasia throughout the intestinal epithelium of mice. Such conditional ablation of Csk also increased the proliferative activity and turnover of IECs, disturbed the differentiation of Paneth and goblet cells, reduced the number of intestinal stem cells, and attenuated the expression of Wnt target genes in the intestine. Moreover, the tyrosine phosphorylation of focal adhesion kinase (FAK) and the activities of both Rac and Yes-associated protein (YAP) were increased in intestinal crypts or organoids of the mutant mice, whereas inhibition of Rac or YAP activity rescued the mutant phenotypes. Our results thus suggest that SFKs promote the proliferation of IECs in intestinal crypts through activation of Rac or YAP and that they thereby contribute to the proper regulation of IEC turnover and intestinal homeostasis.

The life span of intestinal epithelial cells (IECs) is short (3-5 days), and its regulation is thought to be important for homeostasis of the intestinal epithelium. We have now investigated the role of commensal bacteria in regulation of IEC turnover in the small intestine. The proliferative activity of IECs in intestinal crypts as well as the migration of these cells along the crypt-villus axis were markedly attenuated both in germ-free mice and in specific pathogen-free (SPF) mice treated with a mixture of antibiotics, with antibiotics selective for Gram-positive bacteria being most effective in this regard. Oral administration of chloroform-treated feces of SPF mice to germ-free mice resulted in a marked increase in IEC turnover, suggesting that spore-forming Gram-positive bacteria contribute to this effect. Oral administration of short-chain fatty acids (SCFAs) as bacterial fermentation products also restored the turnover of IECs in antibiotic-treated SPF mice as well as promoted the development of intestinal organoids in vitro. Antibiotic treatment reduced the phosphorylation levels of ERK, ribosomal protein S6, and STAT3 in IECs of SPF mice. Our results thus suggest that Gram-positive commensal bacteria are a major determinant of IEC turnover, and that their stimulatory effect is mediated by SCFAs.

This paper describes the innovative flash synthesis of oxide nanoparticles using only a strong exothermic reaction between solids without any external energy, and its implementation for synthesis of titanium(IV) oxide. Flash synthesis is regarded as a type of self-propagating high-temperature synthesis, in which the adiabatic flame temperature of the reaction is greater than the boiling point of the product. This method can be easily applied to produce other oxides, thus offering many benefits, such as energy-saving and short processing-time.

This paper describes the innovative flash synthesis of metal oxide nanoparticles by using only a strong exothermic reaction between solids without any external energy, such as that from an electric furnace, and its implementation for the synthesis of titanium dioxide. Flash synthesis is regarded as a type of combustion synthesis, in which the adiabatic flame temperature of the solid phase reaction is greater than the boiling point of the product. In the experiments, raw materials of different-sized titanium particles and sodium perchlorate were intensively mixed and ignited by an electrical heating foil to produce titanium dioxide through the following reaction: Ti + NaClO 4 → TiO 2 + NaCl. The product was obtained by removing NaCl by washing with distilled water. Evidently, all the products obtained through gasification in the heating process and nucleation and crystal growth in the cooling sublimation process were nanoparticles; the shape and crystal structure of the titanium dioxide product significantly depended on the particle size of titanium used as the raw material. That is, the smaller titanium particles (average size (AS) of 10 μm) resulted in rutile with an irregular shape, and the larger particles (AS of 25 μm) resulted in spheres of anatase with a size of 100–1000 nm. This method can be easily applied to produce other metallic oxides, thus offering many benefits such as easy mass production, energy saving, and short processing time.

This paper describes a new type of combustion synthesis of metal oxide nanoparticles, in which the adiabatic flame temperature of the solid phase reaction is beyond the boiling point of the product, and its implementation for the synthesis of titanium dioxide as photocatalyst. In this study, raw materials comprising titanium particles of different sizes and sodium perchlorate were intensively mixed and ignited by an electrical heating foil to produce titanium dioxide through the following reaction: Ti + NaClO4 → TiO2 + NaCl. The shape and crystal structure of the titanium dioxide product significantly depended on the particle size of the titanium used as raw material. That is, the smaller titanium particles (average size (AS) of 10 μm) resulted in rutile with an irregular shape, whereas the larger particles (AS of 25 μm) resulted in spheres of anatase. The photocatalytic activities of these samples were evaluated using the photocatalytic reactions of aqueous titanium dioxide suspensions containing methanol and acetic acid by irradiation at 298 K in argon atmosphere or in air. The activity of the rutile-rich sample was significantly larger than that of the anatase-rich one in both photocatalytic reactions.

Intestinal epithelial cells contribute to regulation of intestinal immunity in mammals, but the detailed molecular mechanisms of such regulation have remained largely unknown. Stomach-cancer-associated protein tyrosine phosphatase 1 (SAP-1, also known as PTPRH) is a receptor-type protein tyrosine phosphatase that is localized specifically at microvilli of the brush border in gastrointestinal epithelial cells. Here we show that SAP-1 ablation in interleukin (IL)-10-deficient mice, a model of inflammatory bowel disease, resulted in a marked increase in the severity of colitis in association with up-regulation of mRNAs for various cytokines and chemokines in the colon. Tyrosine phosphorylation of carcinoembryonic antigen-related cell adhesion molecule (CEACAM) 20, an intestinal microvillus-specific transmembrane protein of the Ig superfamily, was greatly increased in the intestinal epithelium of the SAP-1-deficient animals, suggesting that this protein is a substrate for SAP-1. Tyrosine phosphorylation of CEACAM20 by the protein tyrosine kinase c-Src and the consequent association of CEACAM20 with spleen tyrosine kinase (Syk) promoted the production of IL-8 in cultured cells through the activation of nuclear factor-κB (NF-κB). In addition, SAP-1 and CEACAM20 were found to form a complex through interaction of their ectodomains. SAP-1 and CEACAM20 thus constitute a regulatory system through which the intestinal epithelium contributes to intestinal immunity.