Recurrent Non-Variceal Upper Gastrointestinal Bleeding among Patients Receiving Dual Antiplatelet Therapy.

BACKGROUND: Patients undergoing dual antiplatelet therapy (DAPT) may experience recurrent gastrointestinal bleeding (GIB). We investigated the clinical characteristics and risk factors for recurrent non-variceal upper gastrointestinal bleeding (NVUGIB) in patients who had experienced NVUGIB while receiving DAPT. METHODS: We enrolled patients diagnosed with NVUGIB while receiving DAPT between 2006 and 2020. Definite bleeding was confirmed by esophagogastroduodenoscopy in all NVUGIB patients. RESULTS: A total of 124 patients were diagnosed with NVUGIB while receiving DAPT. They were predominantly male (n = 103, 83.1%), bleeding mostly from the stomach (n = 94, 75.8%) and had peptic ulcers (n = 72, 58.1%). After the successful hemostasis of NVUGIB, 36 patients (29.0%) experienced at least one episode of recurrent upper GIB, 19 patients (15.3%) died, and 7 (5.6%) patients had a bleeding-related death. Multivariate analysis showed that age was a significant factor for re-bleeding (odds ratio [OR], 1.050; 95% confidence interval [CI]: 1.001-1.102; p-value: 0.047), all-cause mortality (OR, 1.096; 95% CI: 1.020-1.178, p = 0.013), and re-bleeding-related mortality (OR, 1.187; 95% CI: 1.032-1.364, p-value: 0.016). In Kaplan-Meier analysis, the cumulative probabilities of re-bleeding, death, and bleeding-related death were significantly higher in patients aged 70 and older (p = 0.008, <0.001, and 0.009, respectively). CONCLUSIONS: Clinicians should be cautious about re-bleeding and mortality in elderly patients who experience NVUGIB while receiving DAPT.

Clinical Efficacy and Safety of Endoscopic Treatment of Gastrointestinal Stromal Tumors in the Stomach.

Background/Aims: Gastrointestinal stromal tumors (GISTs) are the most common mesenchymal tumors in the stomach. We evaluated the clinical outcomes of endoscopic treatment for gastric GISTs. Methods: This is a single center, retrospective study that enrolled 135 cases of gastric subepithelial tumors (SETs) resected by endoscopic procedures and confirmed as GISTs by histopathology from March 2005 to July 2019. The immediate and long-term clinical outcomes were analyzed retrospectively. Results: The mean patient age was 57.9 years, and the mean tumor size was 2.1 cm. Of the tumors, 43.0% were located in the body, followed by the fundus (26.7%) and cardia (17.0%). Most tumors (85.2%) were resected by endoscopic submucosal dissection, followed by endoscopic mucosal resection (6.7%), submucosal tunneling endoscopic resection (5.9%), and endoscopic full-thickness resection (2.2%). Macroperforation occurred in 4.4% and microperforation in 6.7% of the cases. The R0 resection rate was 15.6%. However, the rate of complete resection by the endoscopic view was 90.4%, of which 54.8% of cases were in the very-low-risk group, followed by the low-risk group (28.1%), intermediate-risk group (11.9%), and high-risk group (5.2%). During 36.5 months of follow-up, recurrence was found in four (3.4%) of the 118 patients who were monitored for more than 6 months (low-risk group, 1/37 [2.7%]; intermediate-risk group, 2/11 [18.2%]; high-risk group, 1/6 [16.7%]). Conclusions: Endoscopic treatment of a GIST appears to be a feasible procedure in selected cases. However, additional surgery should be considered if the pathologic results correspond to intermediate- or high-risk groups.

Long-term outcome of the endoscopic submucosal dissection of early gastric cancer: A comparison between patients with and without liver cirrhosis.

Gastric cancer (GC) and liver cirrhosis (LC) have high incidence rates, particularly in Eastern Asia; however, the long-term clinical outcomes or recurrence of GC following endoscopic submucosal dissection (ESD) in patients with comorbid LC remain unclear. The present study aimed to compare the long-term efficacy and safety of ESD in patients with GC, with and without LC. Patients with early GC (EGC) who had underlying LC and underwent endoscopic treatment (LC-EGC group) were enrolled in the present study. In addition, patients with EGC without LC (non-LC-EGC group) were matched at a ratio of 1:3 via propensity score matching. The clinical outcomes and histopathological data of both groups were analyzed. No significant differences were observed in procedure type, complications [intraprocedural bleeding (11.8%) and perforation (0.0%)], en bloc resection rate (94.1%) and complete resection rate (100%) between the two groups. Multivariate Cox regression analysis demonstrated that procedure time was significantly associated with procedure-associated bleeding [adjusted hazard ratio (HR), 1.017; 95% confidence interval (CI), 1.001-1.032; P=0.033]. Furthermore, LC was significantly associated with cancer recurrence (adjusted HR, 5.482; 95% CI, 1.102-27.279; P=0.038). Taken together, the results of the present study suggest that endoscopic resection of EGC in patients with LC is an effective and safe treatment method. However, further studies are required to assess recurrence.

High Expression of Claudin-4 Is Associated with Synchronous Tumors in Patients with Early Gastric Cancer.

Claudin (CLDN) is a tight junction protein found in human epithelial cells and its altered expression is known to be associated with the progression of gastric cancer. We aimed to investigate the differential expression of CLDN-4 in early gastric cancer (EGC) according to its clinicopathological characteristics. We enrolled 53 patients with EGC who underwent surgical gastric resection from January 2007 to December 2018. The staining intensity of the tumor cells was scored as 0-3, and the percentage of staining was scored as 0-5; high expression was defined if the intensity plus percentage score was 7 or 8, and low expression was defined if the score was 0-6. Among the 53 patients, 16 (30.2%) showed low CLDN-4 expression, while 37 (69.8%) had high CLDN-4 expression. High CLDN-4 expression was significantly associated with intestinal-type EGC (low: 12.5% vs. high: 56.8%, p = 0.003), open-type atrophic change (low: 60.0% vs. high: 90.9%, p = 0.011), and the presence of synchronous tumors (0 vs. 32.4%, p = 0.010), and all 12 EGCs with synchronous tumors showed high CLDN-4 expression. However, expression of CLDN-3, a typical intestinal phenotype CLDN, was neither correlated with CLDN-4 expression nor associated with synchronous tumors. Taken together, high CLDN-4 expression may be considered as an auxiliary tool for screening synchronous tumors in patients with EGC.

Clinicopathological Features of Small Bowel Tumors Diagnosed by Video Capsule Endoscopy and Balloon-Assisted Enteroscopy: A Single Center Experience.

BACKGROUND/AIMS: Small bowel malignancies often present a diagnostic challenge due to their relative rarity and nonspecific clinical symptoms. However, technical developments in endoscopic instruments, including video capsule endoscopy (VCE) and enteroscopy, have allowed for the visualization of the entire small bowel. This study aimed to investigate the clinicopathological features of small bowel malignant tumors diagnosed by VCE and double-balloon enteroscopy (DBE) in a single tertiary center. METHODS: We retrospectively analyzed VCE and DBE findings from Korea University Guro Hospital from January 2010 through September 2018. RESULTS: A total of 510 VCE and 126 DBE examinations were performed in 438 patients. Small bowel malignancies were diagnosed in 28 patients (15 males; mean age, 61.0 years; range, 42 to 81 years). Among them, 8 had lymphoma, 8 had primary adenocarcinoma, 7 had gastrointestinal stromal tumor (GIST) and 5 had metastatic cancer. Abdominal pain and obstructive symptoms were the most common findings in metastatic cancers (4/5, 80%). On the other hand, obscure gastrointestinal bleeding was the most common symptom of GIST (6/7, 85.7%) and adenocarcinoma (3/8, 37.5%). CONCLUSION: Approximately 6% of the patients who underwent either VCE or DBE were diagnosed with small bowel malignancy. These findings demonstrated the different clinical characteristics among small bowel malignancies and merit further study.

CGK062, a small chemical molecule, inhibits cancer upregulated gene 2­induced oncogenesis through NEK2 and ß­catenin.

The mechanisms through which cancer­upregulated gene 2 (CUG2), a novel oncogene, affects Wnt/ß­catenin signaling, essential for tumorigenesis, are unclear. In this study, we aimed to elucidate some of these mechanisms in A549 lung cancer cells. Under the overexpression of CUG2, the protein levels and activity of ß­catenin were evaluated by western blot analysis and luciferase assay. To examine a biological consequence of ß­catenin under CUG2 overexpression, cell migration, invasion and sphere formation assay were performed. The upregulation of ß­catenin induced by CUG2 overexpression was also accessed by xenotransplantation in mice. We first found that CUG2 overexpression increased ß­catenin expression and activity. The suppression of ß­catenin decreased cancer stem cell (CSC)­like phenotypes, indicating that ß­catenin is involved in CUG2­mediated CSC­like phenotypes. Notably, CUG2 overexpression increased the phosphorylation of ß­catenin at Ser33/Ser37, which is known to recruit E3 ligase for ß­catenin degradation. Moreover, CUG2 interacted with and enhanced the expression and kinase activity of never in mitosis gene A­related kinase 2 (NEK2). Recombinant NEK2 phosphorylated ß­catenin at Ser33/Ser37, while NEK2 knockdown decreased the phosphorylation of ß­catenin, suggesting that NEK2 is involved in the phosphorylation of ß­catenin at Ser33/Ser37. Treatment with CGK062, a small chemical molecule, which promotes the phosphorylation of ß­catenin at Ser33/Ser37 through protein kinase C (PKC)α to induce its degradation, reduced ß­catenin levels and inhibited the CUG2­induced features of malignant tumors, including increased cell migration, invasion and sphere formation. Furthermore, CGK062 treatment suppressed CUG2­mediated tumor formation in nude mice. Taken together, the findings of this study suggest that CUG2 enhances the phosphorylation of ß­catenin at Ser33/Ser37 by activating NEK2, thus stabilizing ß­catenin. CGK062 may thus have potential for use as a therapeutic drug against CUG2­overexpressing lung cancer cells.

Severe Endobronchial Inflammation Induced by Aspiration of a Ferrous Sulfate Tablet.

Iron supplements such as ferrous sulfate tablets are usually used to treat iron-deficiency anemia in some elderly patients with primary neurologic disorders or decreased gag reflexes due to stroke, senile dementia, or parkinsonism. While the aspiration of ferrous sulfate is rarely reported, it is a potentially life-threatening condition that can lead to airway necrosis and bronchial stenosis. A detailed history and high suspicion of aspiration are required to avoid delays in diagnosis and treatment. The diagnosis can be confirmed by bronchoscopic examination and a tissue biopsy. Early removal of the aspirated tablet prevents acute complications, such as bronchial necrosis, hemoptysis, and lobar consolidation. Tablet removal is also necessary to prevent late bronchial stenosis. We presented the first case in Korea of a ferrous sulfate tablet aspiration that induced severe endobronchial inflammation.

Isolation and characterization of a serine protease-producing marine bacterium Marinomonas arctica PT-1.

A serine protease-producing marine bacterial strain named as PT-1 was isolated and identified as a family of Marinomonas arctica, based on molecular characterization of 16S rRNA gene sequence, phylogenetic tree, and fatty acid composition analyses. Optimized culture conditions for growth of the bacterium PT-1 and production of protease (ProA) were determined to be pH 8.0 in the presence of 5 % NaCl, at 37 °C during 24 h of incubation in the presence of 1.0 % skim milk. The molecular weight of the purified ProA was estimated to be 63-kDa as a major band by SDS-PAGE. We were intrigued to find that the activity of ProA was not inhibited by pepstatin A, chymostatin, and leupeptin known as inhibitors for cysteine protease. However, phenylmethylsulfonyl fluoride (PMSF) completely inhibited protease activity, suggesting that the ProA is like a serine protease. To the best of our knowledge, this is the first report on serine protease of Marinomonas species.

Role of sigma factor E in regulation of Salmonella Agf expression.

Expression of thin aggregative fimbriae (Agf) in Salmonella, which is responsible for bacterial cell adhesion to surfaces, aggregation, and formation of biofilms, is regulated by a complex mechanism. In order to identify gene(s) involved in the expression of Agf, the TnphoA transposon was introduced into Salmonella typhimurium χ8505 for random mutagenesis. Colonies showing a change from wrinkly-rough morphology to the smooth form were screened for candidates. Through multiple selection processes, a mutant, named S. typhimurium CK167 was selected as the final candidate. Analyses of the nucleotide sequences of TnphoA insertion site identified the insertion in rpoE gene. S. typhimurium CK178, a defined rpoE deletion mutant on χ8505, exhibited the same colony morphology as seen in CK167. The S. typhimurium CK178 strain expressed significantly reduced amounts of AgfD and showed modulated biofilm formation, demonstrating the role of RpoE in AgfD expression. To the best of our knowledge, this is the first report demonstrating that RpoE acts as a regulator in the expression of Agf in Salmonella.

Identification of antigenic Edwardsiella tarda surface proteins and their role in pathogenesis.

Edwardsiella tarda causes an infectious fish disease called edwardsiellosis. Several outer membrane proteins (OMPs) are associated with virulence factors and are attractive as vaccine candidates. In this study, 4 immuno-reactive OMPs of E. tarda were detected using anti-sera from flounder infected with E. tarda. Using matrix-assisted laser desorption/ionization mass spectrometry analyses, 2 of the 4 OMPs were identified as OmpA and murein lipoprotein (Lpp), which are highly conserved surface proteins in gram-negative bacteria. For further characterization of these surface proteins, we generated ompA- and lpp-inactivated mutants by insertion of a kanamycin cassette in the corresponding genes, and named these mutants E. tarda CK99 and CK164, respectively. As expected, immuno-reactive OmpA and Lpp proteins were absent in E. tarda CK99 and CK164, respectively, confirming that OmpA and Lpp are antigenic surface proteins. Interestingly, the LD(50) value of E. tarda CK164 in fish (2.0 × 10(8) colony-forming unit [CFU]/fish) was greater than that of the parental strain (3.0 × 10(7) CFU/fish). The LD(50) of E. tarda CK99 did not differ from that of its parental strain. After administering attenuated E. tarda CK164 to fish, we monitored the E. tarda-specific immune response profile. We observed that the E. tarda-specific serum IgM titer increased in a time-dependent manner, and was much higher than the value observed after the administration of a heat-killed E. tarda control. Moreover, fish vaccinated with E. tarda CK164 were 100% protected when challenged by CK41, a pathogenic strain. Our results suggest that E. tarda CK164 can potentially be used for developing an effective live attenuated vaccine for edwardsiellosis that can be applied in the aquaculture industry.

Requirement of Fur for the full induction of Dps expression in Salmonella enterica serovar typhimurium.

The Dps protein, which is overexpressed in harsh environments, is known to play a critical role in the protection of DNA against oxidative stresses. In this study, the roles of Fur in the expression of the dps gene in Salmonella and the protection mechanisms against oxidative stress in Salmonella cells preexposed to iron-stress were investigated. Two putative Fur boxes were predicted within the promoter region o f th e S. typhimurium dps gene . The profile of dps expression performed by the LacZ reporter assay revealed growth-phase dependency regardless of iron-status under the culture conditions. Thefur mutant, chi4659, evidenced a reduced level of beta-galactosidase as compared to the wild-type strain. The results observed after the measurement of the Dps protein in various Salmonella regulatory mutants were consistent with the results acquired in the reporter assay. This evidence suggested that Fur performs a function as a subsidiary regulator in the expression of dps. The survival ability of Salmonella strains after exposure to oxidative stress demonstrated that the Dps protein performs a pivotal function in the survival of stationary-phase S. typhimurium against oxidative stress. Salmonella cells grown in iron-restricted condition required Dps for full protection against oxidative stress. The CK24 (Deltadps) cells grown in iron-replete condition survived at a rate similar to that observed in the wild-type strain, thereby suggesting the induction of an unknown protection mechanism(s) other than Dps in this condition.

Development of a protein secretion system with the application of sec-dependent protein secretion components.

In order to induce high levels of protein secretion, we have constructed a recombinant plasmid, designated pBP244, into which was incorporated key components of the type-II Sec-dependent secretion system, including LepB (signal peptidase), SecA (ATPase), and SecB (chaperone). The biological activities of the LepB, SecA, and SecB components expressed from genes harbored by pBP244 appeared to play their normal roles. In order to evaluate the protein secretion, a pspA (Streptococcus pneumoniae surface protein A) gene was cloned into pBP244, resulting in pBP438. S. typhimurium harboring pBP438 grown until the stationary phase, secreted a higher level of PspA into the culture supernatants than did the strain harboring pYA3494. The strain harboring pBP438 secreted a supernatant amount 1.71-fold, a periplasmic space amount 1.47-fold, and an outer membrane amount 1.49-fold higher than that of pYA3494. S. typhimurium chi8554 kept the Asd+ plasmid pBP244 and pBP438 for 60 generations in LB broth harboring DAP, thereby indicating that pBP244 and pBP438 were quite stable in the Salmonella strain.