Genetic Variants and Clinical Phenotypes in Korean Patients With Hereditary Hemorrhagic Telangiectasia

Objectives@#. Hereditary hemorrhagic telangiectasia (HHT) is an autosomal dominant vascular disorder characterized by recurrent epistaxis, telangiectasia, and visceral arteriovenous malformations (AVMs). Activin A receptor-like type 1 (ACVRL1/ALK1) and endoglin (ENG) are the principal genes whose mutations cause HHT. No multicenter study has yet investigated correlations between genetic variations and clinical outcomes in Korean HHT patients. @*Methods@#. Seventy-two members from 40 families suspected to have HHT based on symptoms were genetically screened for pathogenic variants of ACVRL1 and ENG. Patients with genetically diagnosed HHT were also evaluated. @*Results@#. In the HHT genetic screening, 42 patients from 24 of the 40 families had genetic variants that met the pathogenic criteria (pathogenic very strong, pathogenic strong, pathogenic moderate, or pathogenic supporting) based on the American College of Medical Genetics and Genomics Standards and Guidelines for either ENG or ACVRL1: 26 from 12 families (50%) for ENG, and 16 from 12 families (50%) for ACVRL1. Diagnostic screening of 42 genetically positive HHT patients based on the Curaçao criteria revealed that 24 patients (57%) were classified as having definite HHT, 17 (41%) as having probable HHT, and 1 (2%) as unlikely to have HHT. Epistaxis was the most common clinical presentation (38/42, 90%), followed by visceral AVMs (24/42, 57%) and telangiectasia (21/42, 50%). Five patients (12%) did not have a family history of HHT clinical symptoms. @*Conclusion@#. Only approximately half of patients with ACVRL1 or ENG genetic variants could be clinically diagnosed as having definite HHT, suggesting that genetic screening is important to confirm the diagnosis.

Effects of Genetic and Pharmacologic Inhibition of COX-2 on Colitis-associated Carcinogenesis in Mice

COX-2 has been inappropriately overexpressed in various human malignancies, and is considered as one of the representative targetsfor the chemoprevention of inflammation-associated cancer. In order to assess the role of COX-2 in colitis-induced carcinogenesis,the selective COX-2 inhibitor celecoxib and COX-2 null mice were exploited in an azoxymethane (AOM)-initiated and dextransulfate sodium (DSS)-promoted murine colon carcinogenesis model. The administration of 2% DSS in drinking water for 1 week aftera single intraperitoneal injection of AOM produced colorectal adenomas in 83% of mice, whereas only 27% of mice given AOM alonedeveloped tumors. Oral administration of celecoxib significantly lowered the incidence as well as the multiplicity of colon tumors. Theexpression of COX-2 and inducible nitric oxide synthase (iNOS) was upregulated in the colon tissues of mice treated with AOM andDSS, and this was inhibited by celecoxib administration. Likewise, celecoxib treatment abrogated the DNA binding of NF-κB, a keytranscription factor responsible for regulating expression of aforementioned pro-inflammatory enzymes, which was associated withsuppression of IκBα degradation. In the COX-2 null (COX-2–/–) mice, there was about 30% reduction in the incidence of colon tumors,and the tumor multiplicity was also markedly reduced (7.7 ± 2.5 vs. 2.43 ± 1.4, P< 0.01). As both pharmacologic inhibition andgenetic ablation of COX-2 gene could not completely suppress colon tumor formation following treatment with AOM and DSS, it isspeculated that other pro-inflammatory mediators, including COX-1 and iNOS, should be additionally targeted to prevent inflammation-associated colon carcinogenesis.

Stable Gastric Pentadecapeptide BPC 157, Robert’s Stomach Cytoprotection/Adaptive Cytoprotection/Organoprotection, and Selye’s Stress Coping Response: Progress, Achievements, and the Future

We reviewed again the significance of the stable gastric pentadecapeptide BPC 157 as a likely mediator of Robert’s stomach cytoprotection/adaptive cytoprotection and organoprotection and as novel mediator of Selye’s stress coping response to reestablish homeostasis. Specific points of BPC 157 therapy and the original concept of Robert’s cytoprotection/adaptive cytoprotection/organoprotection are discussed, including the beneficial effects of BPC 157. First, BPC 157 protects stomach cells and maintains gastric integrity against various noxious agents (Robert’s killing cell by contact) and is continuously present in the gastric mucosa and gastric juice. Additionally, BPC 157 protects against the adverse effects of alcohol and nonsteroidal anti-inflammatory drugs on the gastric epithelium and other epithelia, that is, skin, liver, pancreas, heart (organoprotection), and brain, thereby suggesting its use in wound healing. Additionally, BPC 157 counteracts gastric endothelial injury that precedes and induces damage to the gastric epithelium and generalizes “gastric endothelial protection” to protection of the endothelium of other vessels (thrombosis, prolonged bleeding, and thrombocytopenia). BPC 157 also has an effect on blood vessels, resulting in vessel recruitment that circumvents vessel occlusion and the development of additional shunting and rapid bypass loops to rapidly reestablish the integrity of blood flow (ischemic/reperfusion colitis, duodenal lesions, cecal perforation, and inferior vena caval occlusion). Lastly, BPC 157 counteracts tumor cachexia, muscle wasting, and increases in pro-inflammatory/procachectic cytokines, such as interleukin-6 and tumor necrosis factor-α, and significantly corrects deranged muscle proliferation and myogenesis through changes in the expression of FoxO3a, p-AKT, p-mTOR, and p-GSK-3β (mitigating cancer cachexia).

Anti-Helicobacter pylori, Anti-apoptotic, and Cytoprotective Effects of Threonine Synthesized from Corynebacterium glutamicum in Gastric Epithelial Cells

BACKGROUND/AIMS: Among irritants causing gastric ulcer, Helicobacter pylori (H. pylori) might be pivotal, after which eradication became essential way in either inhibiting ulcerogenesis or preventing ulcer recurrence. Since threonine is essential in either mucus synthesis or cytoprotection, we hypothesized that the dietary threonine from Corynebacterium glutamicum (C. glutamicum) can mitigate the cytotoxicity of H. pylori infection.MATERIALS AND METHODS: RGM-1 cells were challenged with 100 multiplicity of infection H. pylori for 6 hours, during which threonine alone or combination with Corynebacterium sp. was administered and compared for anti-Helicobacter, anti-inflammation, anti-oxidative, and cytoprotective actions.RESULTS: Threonine alone or combination of threonine and C. glutamicum yielded significant bacteriostatic outcomes. The increased expressions of interleukin (IL)-1β, IL-8, Cox-2, and iNOS mRNA after H. pylori infection were significantly decreased with either threonine alone or the combination of threonine and C. glutamicum. The elevated expressions of NF-kB, HIF-1a, and c-jun after H. pylori infection were all significantly decreased with the combination of threonine and broth from C. glutamicum (P < 0.05), leading to significant decreases in 2′,7′-dichlorofluorescein-diacetate (P < 0.01). Tracing further host antioxidative response, the attenuated expression of heme oxygenase-1, Nrf2, and dehydrogenase quinone-1 after H. pylori infection was significantly preserved with combination of threonine and C. glutamicum. H. pylori infection led to significant increases in apoptosis accompanied with Bcl-2 decreases and Bax increases, while the combination of threonine and C. glutamicum significantly attenuated apoptosis, in which attenuated EGF, TGF-β, and VEGF were significantly regulated, while β-catenin did not change.CONCLUSIONS: Threonine synthesized from C. glutamicum significantly alleviated the cytotoxicity of H. pylori in gastric epithelial cells.

Randomized, Double-blind, Placebo-controlled Clinical Trial for the Evaluation of the Efficacy and Safety of Artemisia and Green Tea Extract SD1003F in Volunteers with Helicobacter pylori-associated Gastric Discomfort

BACKGROUND/AIMS: A previous study showed that dietary intervention with Artemisia and green tea extracts, i.e., SD1003F, relieved Helicobacter pylori-associated chronic atrophic gastritis in a mouse model. We continue the research through the current randomized double-blind clinical trial to evaluate the efficacy and safety of the intervention for H. pylori-associated gastric discomfort. MATERIALS AND METHODS: Forty-nine volunteers who tested positive for H. pylori infection received either placebo or SD1003F for 10 weeks and their functional dyspepsia-related quality of life (QOL) was evaluated. H. pylori infection using a urea breath test (UBT), measurement of pepsinogen level using GastroPanel. Adverse effects with biochemical changes were also evaluated. RESULTS: SD1003F administration significantly improved health related-QOL, including dietary intake, emotional stability, life pattern, and social factors relevant to gastric discomfort, in comparison to the control (P < 0.05). The mean UBT measurement significantly decreased in the SD1003F group (P < 0.05). In 2 of the 24 volunteers, SD1003F alone eradicated H. pylori infection, with significant improvements in endoscopic findings. GastroPanel analysis revealed significant improvements that reflect rejuvenation of gastric atrophy in the SD1003F group. No significant side effect was observed in any participant. CONCLUSIONS: SD1003F (Artemisia and green tea extract), is a potential phytochemical to improve H. pylori-associated gastric discomfort.

Combined Extracts of Artemisia and Green Tea, Mitigated Alcoholic Gastritis Via Enhanced Heat-shock Protein 27 / 대한소화기학회지

BACKGROUND/AIMS: Several lines of evidence from epidemiologic and laboratory studies have shown that the consumption of Artemisia or green tea extracts (MPGT) is inversely associated with the risk of alcohol-induced damage and other chronic diseases. Supported by previous studies showing that the combined extract of Artemisia and green tea, MPGT, exerted significantly either antioxidative or anti-inflammatory actions against Helicobacter pylori-associated gastric diseases, it was hypothesized that MPGT can offer protection against alcoholic gastritis. METHODS: Ethanol was administered to induce gastric damage in Wistar rats, which had been pretreated with various doses of MPGT, to measure the rescuing action of a MPGT pretreatment against ethanol-induced gastric damage. In addition, the molecular mechanisms for the preventive effects were examined. RESULTS: The MPGT pretreatment (100, 300, and 500 mg/kg) alleviated the ethanol-induced gastric damage, which was evidenced by the significant decrease in calcium-dependent phospholipase A2, MAPKs, and NF-κB levels compared to ethanol alone. Furthermore, the MPGT pretreatment preserved 15-prostaglandin dehydrogenase, whereas cyclooxygenase-2 was decreased significantly. All of these biochemical changes led to the significant alleviation of alcohol-associated gastric mucosal damage. Ethanol significantly increased the TUNEL positivity in the stomach, but MPGT decreased the apoptotic index significantly, which was associated with significantly lower pathological scores of ethanol-induced mucosal ulcerations. The significant protective changes observed alcoholic gastritis with MPGT were related to the increased expression of cytoprotective genes, such as heat-shock protein (HSP)27, HSP60, and PDGF. CONCLUSIONS: The efficient anti-inflammatory, anti-apoptotic, and regenerative actions of MPGT make it a potential nutrient phytoceutical to rescue the stomach from alcoholic gastritis.

Liquid Biopsy: Current Status and Future Perspective in Gastric Cancer and Helicobacter Infection / 대한Helicobacter연구학회지

Precision medicine stands for 4Ps - precise, preventive, participatory, and personal; in which “precision” is important because the current modern medicine starts from “trial and error,” and “one does not fit all”. Current targeted therapies for cancer have changed treatment approaches and led the precision medicine; however, clinical use of liquid biopsy, using blood or other liquid specimens to characterize circulating tumor cells (CTC) or tumor genes instead of biopsies of tumor tissues, still awaits availability of more information regarding non-invasive cancer detection and characterization, prediction of treatment response, monitoring the disease course and relapse possibilities, identification of mechanisms of drug resistance, and newer pathogenesis. In this review, we will introduce the basic concept of CTC, circulating cell free DNA, and exosomes and their possible application for gastric cancer relevant with Helicobacter pylori infection.

Comparison of the Outcomes of Peroral Endoscopic Myotomy for Achalasia According to Manometric Subtype

BACKGROUND/AIMS: We evaluated whether manometric subtype is associated with treatment outcome in patients with achalasia treated by peroral endoscopic myotomy (POEM). METHODS: High-resolution manometry data and Eckardt scores were collected from 83 cases at two tertiary referral centers where POEM is performed. Manometric tracings were classified according to the three Chicago subtypes. RESULTS: Among the 83 cases, 48 type I, 24 type II, and 11 type III achalasia cases were identified. No difference was found in pre-POEM Eckardt score, basal lower esophageal sphincter (LES) pressure, or integrated relaxation pressure (IRP) among the type I, type II, and type III groups. All three patient groups showed a significant improvement in post-POEM Eckardt score (6.1±2.1 to 1.5±1.5, p=0.001; 6.8±2.2 to 1.2±0.9, p=0.001; 6.6±2.0 to 1.6±1.4, p=0.011), LES pressure (26.1±13.8 to 15.4±6.8, p=0.018; 32.3±19.0 to 19.2±10.4, p=0.003; 36.8±19.2 to 17.5±9.7, p=0.041), and 4s IRP (21.5±11.7 to 12.0±8.7, p=0.007; 24.5±14.8 to 12.0±7.6, p=0.002; 24.0±15.7 to 11.8±7.1, p=0.019) at a median follow-up of 16 months. CONCLUSIONS: POEM resulted in a good clinical outcome for all manometric subtypes.

Heme Oxygenase-1 Induction and Anti-inflammatory Actions of Atractylodes macrocephala and Taraxacum herba Extracts Prevented Colitis and Was More Effective than Sulfasalazine in Preventing Relapse

BACKGROUND/AIMS: In inflammatory bowel disease (IBD), repeated bouts of remission and relapse occur in patients and can impose a risk of colitis-associated cancer. We hypothesized that plant extracts of Atractylodes macrocephala (AM) or Taraxacum herba (TH) may be better than sulfasalazine for treating this disease because these extracts can promote additional regeneration. METHODS: Murine intestinal epithelial IEC-6 cells were pretreated with AM or TH before a lipopolysaccharide (LPS)-induced challenge. Acute colitis was induced with 7 days of dextran sulfate sodium (DSS) in male C57BL/6 mice, and extracts of AM and TH were administered for 2 weeks before DSS administration. RESULTS: In vitro studies demonstrated that AM or TH treatment reduced LPS-induced COX-2 and tumor necrosis factor-α mRNA levels but increased heme oxygenase-1 (HO-1). Oral preadministration of AM and TH rescued mice from DSS-induced colitis by inhibiting inflammatory mediators via inactivated extracellular signal regulated kinase and repressed nuclear factor κB and signal transducer and activator of transcription 3, but the effect was weaker for sulfasalazine than that for the extracts. Anti-inflammatory activities occurred via the inhibition of macrophage and T lymphocyte infiltrations. Unlike sulfasalazine, which did not induce HO-1, TH extracts afforded significant HO-1 induction. CONCLUSIONS: Because the AM or TH extracts were far superior in preventing DSS-induced colitis than sulfasalazine, AM or TH extracts can be considered natural agents that can prevent IBD relapse.

Role of Inhibitory Transforming Growth Factor-β Signal Smad7 in Helicobacter pylori-associated Gastric Damage / 대한소화기학회지

BACKGROUND/AIMS: Transforming growth factor-beta (TGF-β) is a cytokine implicated in the susceptibility, development, and progression of gastrointestinal cancer and certain other neoplasms. In the later stages of cancer, TGF-β not only acts as a bystander of host-immune response, but also contributes to cell growth, invasion, and metastasis. In the current study, we generated gastric mucosal cells that stably express Smad7, and explored the Helicobacter pylori-associated biological changes between mock-transfected and Smad7-transfected RGM1 cells. METHODS: RGM1 cells stably transfected with Smad7 were infected with H. pylori, and molecular changes in apoptotic markers and inflammatory mediators were examined. Several candidate genes were explored in Smad7-overexpressing cells after H. pylori infection. RESULTS: Overexpression of Smad7 in RGM1 cells significantly increased the H. pylori-induced cytotoxicity compared to mock-transfected cells. Exaggerated increases in inflammatory mediators, cyclooxygenase 2, inducible NO synthase, and augmented apoptosis were noted in Smad7-overexpressing cells, whereas mitigated heme oxygenase 1 was noted in Smad7- overexpressing cells. These phenomena were reversed in cells transfected with Smad7 siRNA. CONCLUSIONS: These data suggest that inhibition of Smad7 is a possible target for mitigating H. pylori-associated inflammation.

Bile Flow Phantom Model and Animal Bile Duct Dilation Model for Evaluating Biliary Plastic Stents with Advanced Hydrophilic Coating

BACKGROUND/AIMS: The efforts to improve biliary plastic stents (PSs) for decreasing biofilm formation and overcome short patency time have been continued. The aim of this study is to evaluate the effect of advanced hydrophilic coating for patency and biodurability of PS. METHODS: Using an in vitro bile flow phantom model, we compared patency between prototype PS with hydrophilic coating (PS+HC) and prototype PS without hydrophilic coating (PS-HC). We performed an analysis of the degree of luminal narrowing by microscopic examination. Using an in vivo swine bile duct dilation model made by endoscopic papillary closure and stent insertion, we evaluated biodurability of hydrophilic coating. RESULTS: In the phantom model, PS+HC showed less biofilm formation and luminal narrowing than PS-HC at 8 weeks (p<0.05). A total of 31 stents were inserted into the dilated bile duct of seven swine models, and 24 stents were successfully retrieved 8 weeks later. There was no statistical difference of stent patency between the polyethylene PS+HC and the polyurethane PS+HC. The biodurability of hydrophilic coating was sustained up to 8 weeks, when assessing the coating layer by scanning electron microscopy examination. CONCLUSIONS: Advanced hydrophilic coating technology may extend the patency of PS compared to uncoated PS.

Optimal Methods for the Management of Iatrogenic Colonoscopic Perforation

BACKGROUND/AIMS: Colonoscopic perforations have been managed with exploratory laparotomy, and have resulted in some morbidity and mortality. Recently, laparoscopic surgery is commonly performed for this purpose. The aim of this study was to compare the outcomes of several management strategies for iatrogenic colonoscopic perforations. METHODS: We retrospectively reviewed the medical records of patients who had been treated for colonoscopic perforation between January 2004 and April 2013 at CHA Bundang Medical Center in Korea. RESULTS: A total of 41 patients with colonoscopic perforation were enrolled. Twenty patients underwent conservative management with a success rate of 90%. Surgical management was performed in 23 patients including two patients who were converted to surgical management after the failure of the initial conservative management. Among 14 patients who underwent surgery at 8 hours after the perforation, there was no considerable difference in adverse outcomes between the laparotomy group and the laparoscopic surgery group. The medical costs and claim rate were 1.45 and 1.87 times greater in the exploratory laparotomy group, respectively. CONCLUSIONS: Conservative management of colonoscopic perforation could be an option for patients without overt symptoms of peritonitis or with a small defect size. If surgical management is required, laparoscopic surgery may be considered as the initial procedure even with a delayed diagnosis.

Communicating Tubular Esophageal Duplication Combined with Bronchoesophageal Fistula

Esophageal duplication (ED) is rarely diagnosed in adults and is usually asymptomatic. Especially, ED that is connected to the esophagus through a tubular communication and combined with bronchoesophageal fistula (BEF) is extremely rare and has never been reported in the English literature. This condition is very difficult to diagnose. Although some combinations of several modalities, such as upper gastrointestinal endoscopy, esophagography, computed tomography, magnetic resonance imaging, and endoscopic ultrasonography, can be used for the diagnosis, the results might be inconclusive. Here, we report on a patient with communicating tubular ED that was incidentally diagnosed on the basis of endoscopy and esophagography during the postoperational evaluation of BEF.

Double-Scope Peroral Endoscopic Myotomy (POEM) for Esophageal Achalasia: The First Trial of a New Double-Scope POEM

With the accumulation of clinical trials demonstrating its efficacy and safety, peroral endoscopic myotomy (POEM) has emerged as a less invasive treatment option for esophageal achalasia compared with laparoscopic Heller myotomy. However, the difficulty in determining the exact extent of myotomy, a critical factor associated with the success and safety of the procedure, remains a limitation. Although the various endoscopic landmarks and ancillary techniques have been applied, none of these has been proven sufficient. As a solution for this limitation, the double-scope POEM technique with a second endoscope to assure the exact length of the submucosal tunnel has been applied since 2014. Before double-scope POEM was introduced, the second endoscope was applied only to confirm the accuracy of the procedure. In the present study, we performed double-scope POEM in the treatment of esophageal achalasia through a novel procedure of simultaneous application of the second endoscope to assist in the conventional POEM procedure.

Highlights from the 52nd Seminar of the Korean Society of Gastrointestinal Endoscopy

In this July issue of Clinical Endoscopy, state-of-the-art articles selected from the lectures delivered during the 52nd Seminar of the Korean Society of Gastrointestinal Endoscopy (KSGE) on March 29, 2015 are covered, focusing on highlighted educational contents relevant to either diagnostic or therapeutic gastrointestinal (GI) endoscopy. Our society, the KSGE, has continued to host this opportunity for annual seminars twice a year over the last 26 years and it has become a large-scale prestigious seminar accommodating over 4,000 participants. Definitely, the KSGE seminar is considered as one of the premier state-of-the-art seminars dealing with GI endoscopy, appealing to both the beginner and advanced experts. Lectures, live demonstrations, hands-on courses, as well as an editor school, which was an important consensus meeting on how to upgrade our society journal, Clinical Endoscopy, to a Science Citation Index (Expanded) designation were included in this seminar. The 52nd KSGE seminar consisted of more than 20 sessions, including special lectures, concurrent sessions for GI endoscopy nurses, and sessions exploring new technologies. This is a very special omnibus article to highlight the core contents divided into four sessions: upper GI tract, lower GI tract, pancreatobiliary system, and other specialized sessions.

Clinical Endoscopy as One of Leading Journals in Gastrointestinal Endoscopy

Clinical Endoscopy (CE) is an official open access journal published bimonthly by the Korean Society of Gastrointestinal Endoscopy (KSGE, http://www.gie.or.kr) and is listed on PMC, PubMed and SCOPUS. The KSGE was established on August 14, 1976, and the journal of the KSGE was published in Korean for the first time in November 1981. The journal was then titled the "Korean Journal of Gastrointestinal Endoscopy" and was published in Korean untill the July 2011 issue. The journal was published in English from the September 2011 issue under the official title of CE. In this review, the past and present of CE are discussed and future perspectives are introduced. In addition, the efforts to progress to a "first come, first served journal" in the field of gastrointestinal endoscopy and to be indexed in Science Citation Index will be described.

Extragastroesophageal Malignancy-Associated Secondary Achalasia: A Rare Association of Pancreatic Cancer Rendering Alarm Manifestation

Secondary achalasia or pseudoachalasia is a rare esophageal motor abnormality, which mimics primary achalasia; it is not easily distinguishable from idiopathic achalasia by manometry, radiological examination, or endoscopy. Although the majority of reported pseudoachalasia cases are associated with neoplasms at or near the esophagogastric (EG) junction, other neoplastic processes or even chronic illnesses such as rheumatoid arthritis can lead to the development of pseudoachalasia, for example, mediastinal masses, gastrointestinal (GI) tumors of the liver and biliary tract, and non-GI malignancies. Therefore, even if a patient presents with the typical findings of achalasia, we should be alert to the possibility of other GI malignancies besides EG tumors. For instance, pancreatic cancer was found in the case reported here; only four such cases have been reported in the literature. A 47-year-old man was admitted to our center with a 3-month history of dysphagia. His endoscopic and esophageal manometric findings were compatible with primary achalasia. However, unresponsiveness to diverse conventional achalasia treatments led us to suspect secondary achalasia. An active search led to a diagnosis of pancreatic mucinous cystadenocarcinoma invading the gastric fundus and EG junction. This rare case of pseudoachalasia caused by pancreatic carcinoma emphasizes the need for suspecting GI malignancies other than EG tumors in patients refractory to conventional achalasia treatment.

Role of Clinical Endoscopy in Emphasizing Endoscope Disinfection

Based on the unexpected Middle East respiratory syndrome (MERS) outbreak in Korea, it was established that the virus can spread easily, MERS exposure in hospitals carries an extreme risk for infection as well as mortality, and the sharing of information was essential for infection control. Although the incidence of exogenous infections related to contaminated endoscopes is very low, the majority of published outbreaks have been caused by various shortcomings in reprocessing procedures, including insufficient training or awareness. Ever since the inauguration of "Clinical Endoscopy" as an English-language journal of the Korean Society of Gastrointestinal Endoscopy in 2011, it has published several articles on disinfection of the endoscope and its accessories. Many Science Citation Index journals have also emphasized high-level disinfection of the gastrointestinal endoscope. Many papers have been produced specifically, since the outbreak of carbapenem-resistant Enterobacteriaceae in 2013. The recent review papers concluded that quality control is the most important issue among all the aspects of procedural care, including the efficiency of the gastrointestinal endoscopy unit and reprocessing room. Thorough reprocessing of endoscopes using high-level disinfection and sterilization methods may be essential for reducing the risk of infection.

Image Quality Analysis of Various Gastrointestinal Endoscopes: Why Image Quality Is a Prerequisite for Proper Diagnostic and Therapeutic Endoscopy

Arising from human curiosity in terms of the desire to look within the human body, endoscopy has undergone significant advances in modern medicine. Direct visualization of the gastrointestinal (GI) tract by traditional endoscopy was first introduced over 50 years ago, after which fairly rapid advancement from rigid esophagogastric scopes to flexible scopes and high definition videoscopes has occurred. In an effort towards early detection of precancerous lesions in the GI tract, several high-technology imaging scopes have been developed, including narrow band imaging, autofocus imaging, magnified endoscopy, and confocal microendoscopy. However, these modern developments have resulted in fundamental imaging technology being skewed towards red-green-blue and this technology has obscured the advantages of other endoscope techniques. In this review article, we have described the importance of image quality analysis using a survey to consider the diversity of endoscope system selection in order to better achieve diagnostic and therapeutic goals. The ultimate aims can be achieved through the adoption of modern endoscopy systems that obtain high image quality.

Unpleasant Journey from Helicobacter pylori-associated Gastritis to Gastric Cancer: Cancer Prevention by Taking a Detour / 대한소화기학회지

As a commensal or a pathogen, Helicobacter pylori can change the balance of a complex interaction that exists among gastric epithelial cells, microbes, and their environment. Therefore, unraveling this complex relationship of these mixtures can be expected to help prevent cancer as well as troublesome unmet medical needs of H. pylori infection. Though gastric carcinogenesis is a multi-step process, precancerous lesion can be reversible in the early phase of mucosal damage before reaching the stage of no return. However, biomarkers to predict rejuvenation of precancerous atrophic gastritis have not been identified yet and gastric cancer prevention is still regarded as an impregnable fortress. However, when we take the journey from H. pylori-associated gastritis to gastric cancer, it provides us with the clue for prevention since there are two main preventive strategies: eradication and anti-inflammation. The evidence supporting the former strategy is now ongoing in Japan through a nation-wide effort to eradicate H. pylori in patients with chronic gastritis, but suboptimal apprehension to increasing H. pylori resistance to antibiotics and patient non-compliance still exists. The latter strategy has been continued in the author's research center under siTRP (short-term intervention to revert premalignant lesion) strategy. By focusing on the role of inflammation in the development of H. pylori-associated gastric carcinogenesis, this review is intended to explain the connection between inflammation and gastric cancer. Strategies on H. pylori eradication, removal of inflammation, and reverting preneoplastic lesion will also be introduced. In the end, we expect to be able to prevent gastric cancer by take a detour from the unpleasant journey, i.e. from H. pylori-associated gastritis to gastric cancer.