본 연구에서는 '예상하지 못한 현상'을 관찰한 고등학생들이 설정하는 탐구문제 특징을 조사하고, 탐구문제 설정에 있어 과학적 정보제공이 미치는 영향을 확인하였다. 연구 대상은 서울시 소재 인문계 고등학교 2학년 학생 126명으로, 이들은 A집단 (N=66)과 B집단 (N=60)으로 무작위 구분되었다. 연구 과정에서 모든 학생들은 약 45초 분량의 예상하지 못한 현상 영상을 20분간 반복하여 시청하고 영상과 관련하여 자신이 수행하고 싶은 탐구주제를 활동지에 자유롭게 작성하였다. 이때 B집단 학생들에게 제공된 활동지에만 예상하지 못한 현상에 관한 과학적 정보가 추가적으로 포함되어 있던 것이 특징이었다. 연구 결과, 학생들은 집단에 관계 없이 예상하지 못한 현상에 대하여 '원인 지향 탐구문제 (현상의 원인을 밝히고자 함)'보다는 '호기심 지향 탐구문제 (현상의 이유보다는 자신이 하고 싶은 탐구를 함)'를 더 많이 설정하는 경향이 있었다. 호기심 지향 탐구문제 중에서는 '새로운 결과 탐구문제 (실험상황 등을 단순 조작하여 어떤 새로운 결과가 나타나는지를 탐구)'가 대부분을 비중을 차지하였다. 또한, 과학적 정보를 제공받은 학생들은 그렇지 않은 학생들에 비해 제공된 정보를 유의미하게 더 많이 이용하여 탐구문제를 설정하는 경향이 있지만 (χ2(1)=8.996, p< .01), 그렇다고 할지라도 이들이 원인 지향탐구문제를 유의미하게 더 많이 설정하게 되는 것은 아니라는 사실도 확인되었다 (χ2(1)=1.376, p >.05). 연구 결과는 제공된 정보의 부족, 제공된 정보의 내면화 기회 부족, 개인적 호기심 추구 성향, 직관적 사고 성향 등 네 가지 관점에서 논의되었고, 이를 통해 탐구문제 설정에 대한 시사점이 제안되었다.

In this study, we investigated the characteristics of inquiry problems set by high school students who observed an 'unexpected phenomenon' and identified the effects of providing scientific information on setting inquiry problems. The subjects of this study were 126 eleventh grade students in Seoul that were randomly assigned to group A (N=66) and group B (N=60). In the study, watching a video of about 45 seconds of the unexpected phenomenon repeatedly for 20 minutes, all the students freely wrote inquiry problems that they wanted to carry out in their handouts. At this time, it is characterized that only the handout of group B additionally included scientific information on the unexpected phenomenon. As a result of the study, students, regardless of group, set more 'curiosity-oriented inquiry problems (i.e., focusing on inquiries they want to do rather than revealing what might be the cause of the phenomenon)' rather than going into a 'cause-oriented inquiry problem solving (i.e., revealing the cause of the phenomenon).' Among the curiosity-oriented inquiry problems, most of them were 'new-result inquiry problems (i.e., investigating what new results will occur by simply manipulating experimental situations).' It was also found that students who were provided with the scientific information tended to set significantly more inquiry problems using the provided information than those who were not (χ2(1)=8.996, p< .01), nevertheless the students with the scientific information did not set significantly more cause-oriented inquiry problems (χ2(1)=1.376, p >.05). The findings have been discussed from the four perspectives (i.e., lack of provided information, lack of opportunities to internalize the provided information, personal curiosity-seeking, and intuitive thinking), and implications for inquiry problem setting were suggested.

Patients with esophageal dysphagia need a step-by-step approach for diagnosis and treatment. Endoscopic with biopsy and barium esophagogram are the essential tests evaluating anatomical abnormality and esophageal bolus stasis. Further imaging or esophageal function tests such as high-resolution esophageal manometry, functional endoluminal imaging probe, CT or endoscopic ultrasound are required. In the case of dysphagia due to esophageal motility disorder, whether it is the major motility disorder or minor motility disorder should be identified in high resolution manometry. Major motility disorders show esophagogastric junction obstruction or major peristaltic defects. In this case, the severity of the symptoms should be assessed and patients who need endoscopic or surgical treatment targeting lower esophageal sphincter should be screened. Impaired lower esophageal sphincter relaxation (achalasia, esophagogastric junction outflow obstruction, esophageal spasm or abnormal hypercontraction (jackhammer esophagus), hypotensive contraction (ineffective esophageal motility, failed peristalsis), esophageal hypersensitivity (noncardiac chest pain), gastroesophageal reflux disease and esophageal bolus stasis are the possible mechanisms causing dysphagia symptoms. The proper medical treatment depends on underlying mechanisms. (Korean J Gastroenterol 2021;77:71-76)

Dysphagia is difficulty in swallowing that can be caused by a number of disorders that involve either the oropharynx or the esophagus. Specific endoscopic treatment for dysphagia depends on its etiology, whether the dysphagia is caused by mechanical narrowing or a motor disorder. Variable endoscopic treatment strategies can be used to manage dysphagia. Patient with dysfunction of the upper esophageal sphincter may benefit from esophageal dilationor injection of botulinum toxin. Pneumatic balloon dilation, injection of botulinum toxin, peroral endoscopic myotomy can be considered as treatment options for esophageal motility disorders. Endoscopic dilation is the treatment choice of esophageal stricture, while intraluminal steroid injection and temporary stent can be considered in refractory benign esophageal stricture. Self-expandable metal stent insertion can be considered for dysphagia with malignant cause. (Korean J Gastroenterol 2021;77:77-83)

Colorectal perineuriomas are benign mucosal-based mesenchymal tumors composed of perineurial cells and show serrated or hyperplastic crypts in epithelium on histopathological evaluation. Most perineuriomas are usually presented as sessile polyps and often as subepithelial tumors. In this case, colonoscopy revealed a rectal subepithelial tumor (measuring approximately 7 mm) with yellowish- colored normal mucosa. A rectal neuroendocrine tumor was suspected, and cap-assisted endoscopic mucosal resection was performed. Histopathological examination of the resected specimen revealed bland spindle cells showing immunopositivity for CD34. The patient was finally diagnosed with rectal perineurioma. (Korean J Gastroenterol 2021;77:84-87)

The pegylated interferon plus ribavirin combination therapy has been used as the primary treatment for chronic hepatitis C (CHC) but fails to produce a sustained viral response (SVR) in many patients. In recent years, the treatment of CHC has been rapidly changing because of the introduction of direct-acting antivirals (DAAs), which have a high cure rate. However, retreatment of patients after failure of the first DAA therapy is difficult. We report two rare cases of CHC that showed acquired SVR with other DAA combinations after failure to daclatasvir and asunaprevir. (Korean J Gastroenterol 2021;77:88-91)

Esophageal motility disorders were re-defined when high-resolution manometry was employed to better understand their pathogenesis. Newly developed parameters including integrated relaxation pressure (IRP), distal contractile integral, and distal latency showed better diagnostic yield compared with previously used conventional parameters. Therefore, Chicago classification was formulated, and its diagnostic cascade begins by assessing the IRP value. However, IRP showed limitation due to its inconsistency, and other studies have tried to overcome this. Recent studies showed that provocative tests, supplementing the conventional esophageal manometry protocol, have improved the diagnostic yield of the esophageal motility disorders. Therefore, position change from supine to upright, solid or semi-solid swallowing, multiple rapid swallows, and the rapid drink challenge were newly added to the manometry protocol in the revised Chicago classification version 4.0. Impedance planimetry enables measurement of bag cross-sectional area at various locations. The functional lumen imaging probe (FLIP) has been applied to assess luminal distensibility. This probe can also measure pressure, serial cross-sectional areas, and tension-strain relationship. The esophagogastric junction's distensibility is decreased in achalasia. Therefore, EndoFLIP can be used to assess contractility and distensibility of the esophagus in the patients with achalasia, including repetitive antegrade or retrograde contractions. EndoFLIP can detect achalasia patients with relatively low IRP, which was difficult to diagnose using the current high-resolution manometry. EndoFLIP also provides information on the contractile activity and distensibility of the esophageal body in patients with achalasia. The use of provocative tests, newly added in Chicago classification 4.0 version, and EndoFLIP can expand understanding of esophageal motility disorders. (Korean J Gastroenterol 2021;77:64-70)

Dysphagia has been reported to be relatively common and seems to be increased in Korea. Dysphagia can be classified as oropharyngeal dysphagia or esophageal dysphagia. In patients with swallowing difficulties, it is important to determine whether the dysphagia is oropharyngeal or esophageal. Patients with orophayngeal dysphagia are likely to develop aspiration and aspiration pneumonia, so accurate diagnosis should be made in the early stages of complaining of swallowing difficulties. Patients with orophayngeal dysphagia complained difficulty initiating a swallow. Swallowing may be accompanied by coughing, choking, nasopharyngeal regurgitation, aspiration, and a sensation of residual food remaining in the pharynx. Patients with esophageal dysphagia complained difficulty swallowing several seconds after initiating a swallow and a sensation of food getting stuck in the esophagus. Esophageal dysphagia should be characterized by analyzing whether foods that cause swallowing difficulties are solid, liquids or both, whether symptoms are progressive or intermittent, how severe, and associated symptoms, such as weight loss, heartburn, or regurgitation. The approach to diagnostic testing to determine the cause of esophageal dysphagia is based upon the medical history. If esophageal motility disorder is suspected, barium esophagogram is performed first, and upper endoscopy is performed first if structural abnormalities are suspected. If an upper endoscopy shows normal findings, but the esophagus is still suspected of mechanical obstruction, a barium esophagogram is performed. Esophageal manometry should be performed in patients with swallowing difficulties who are suspected of esophageal motility disorder or have normal findings in upper endoscopy. (Korean J Gastroenterol 2021;77:57-63)

대장 종양의 현미부수체 불안정성(microsatellite instability, MSI)과 부적합 결합 DNA 교정 기능 소실(mismatch repair deficiency, dMMR) 검사는 대장암 환자 치료제 선택의 중요한 고려 요소이다. MSI 검사는 Bethesda 패널 polymerase chain reaction (PCR)을 이용하며, MMR 검사는 MLH1, MSH2, MSH6, PMS2를 포함한 immunohistochemistry 패널을 이용한다. 이러한 검사를 위해서는 추가적인 조직 샘플 획득이 필요하며, 기존의 조직 슬라이드 검사 비용 외에 추가적인 비용이 발생하게 된다. 이 연구에서는 딥러닝 기법을 이용하여 일반적인 조직 슬라이드에서 MSI와 dMMR의 분석을 가능하게 하였고, 추가 분석에 따로 필요한 비용과 시간을 절약할 수 있게 하였다.
저자들은 독일, 네덜란드, 영국, 미국의 MSDETECT 컨소시엄 스터디에서 총 8,836개 대장 종양의 헤마톡실린/에오진 염색 슬라이드와 분자 분석 결과를 수집하였고, 모든 슬라이드를 리뷰하여 슬라이드의 종양 조직 포함 유무 및 이미지 퀄리티를 확인하였다. 딥러닝 시스템이 헤마톡실린/에오진 염색 슬라이드에서 MSI 또는 dMMR 결과를 예측하도록 학습시켰고, 예측 정확도를 다기관 코호트를 이용하여 검증하였다. 그 결과 평균 area under the receiver operating characteristics 값이 0.92, 민감도가 95%, 특이도가 67%로 확인 되었다. 특히 슬라이드 이미지의 색 보정(color normalization) 후의 dMMR 예측에 대한 area under the receiver operating characteristics 값은 0.96이었다. 저자들은 이러한 시스템이 실제 임상에서 대장암 조직 검체를 분석을 위한 비용 절감 및 효율 증대 효과를 보일 것으로 기대하였다.