Yoon Jin Choi

Do antiplatelets increase the risk of bleeding after endoscopic submucosal dissection of gastric neoplasms

BACKGROUND It is rarely known whether antiplatelets increase the risk of bleeding after endoscopic submucosal dissection (ESD). OBJECTIVE To evaluate the effect of antiplatelets on post-ESD bleeding. DESIGN Retrospective study. SETTING Single, tertiary-care referral center. PATIENTS This study involved 1591 gastric neoplasms (815 adenomas and 776 early gastric cancers) in 1503 patients who had ESD between April 2005 and April 2010. INTERVENTION ESD. MAIN OUTCOME MEASUREMENTS Overt hematemesis/hematochezia, a drop of hemoglobin >2 g/dL from baseline, or requirement of endoscopic hemostasis, angiographic embolization, and/or transfusion. RESULTS Of 1591 subjects, 274 took antiplatelets, among whom 102 discontinued them for 7 days or more before ESD. Post-ESD bleeding occurred in 94 subjects including 20 from the continuation group, 6 from the withdrawal group, and 68 from the no-antiplatelet group. In univariate analysis, antiplatelets, early gastric cancer (EGC), comorbidity, and specimen diameter were related to post-ESD bleeding. In multivariate analysis, EGC (odds ratio [OR] 1.839; 95% confidence interval [CI], 1.168-2.896; P = .009), comorbidity (OR 2.246; 95% CI, 1.280-3.939; P = .005), and specimen diameter (OR 2.315; 95% CI, 1.282-4.180; P = .005) were independent risk factors of post-ESD bleeding, whereas antiplatelet usage was not (OR 1.596; 95% CI, 0.877-2.903; P = .126). In subgroup analysis, continuous antiplatelet usage was not found to be an independent risk factor of post-ESD bleeding in multivariate analysis (OR 2.027; P = .146). Among 102 subjects who discontinued antiplatelets, 1 developed an acute cerebral infarction (1.0%). LIMITATION A retrospective, single-center analysis. CONCLUSION In ESD for antiplatelet users, continuous administration was not found to have an independent significant association with bleeding.

Helicobacter pylori-induced epithelial-mesenchymal transition, a potential role of gastric cancer initiation and an emergence of stem cells

We know little concerning the expression of transforming growth factor-β1 (TGF-β1) and TGF-β1-induced epithelial-mesenchymal transition (EMT) markers in gastric mucosa and their changes after eradication of Helicobacter pylori infection have not yet been clarified. In the present study, we compared the time course of messenger RNA (mRNA) expression of TGF-β1 and five EMT markers (Twist, Snail, Slug, vimentin and E-cadherin) in 111 controls, 55 patients with gastric dysplasia and 71 patients with early gastric cancer, following eradication of H.pylori. mRNA levels in non-cancerous gastric mucosa were measured using quantitative real time-polymerase chain reaction and the histologic findings of gastric mucosa were compared before and after eradication. The average duration of follow-up was 46.7 months (6.0-112.4). The levels of TGF-β1, Twist, Snail, Slug and vimentin mRNA, in addition to levels of CD44 detected by immunohistochemistry, showed all up-regulation in patients with dysplasia or early gastric cancer compared with controls (P < 0.05); moreover, the mRNA levels of E-cadherin, an epithelial marker, were decreased in these patients compared with the control group (P < 0.001). Eradication of H.pylori reduced the expression of TGF-β1, Twist, Snail, Slug and vimentin mRNA (P-value for slope <0.001), as well as the immunohistochemical expression of CD44 (P = 0.014), whereas it enhanced the expression of E-cadherin (P-value for slope < 0.05). Thus, H.pylori infection may trigger the TGF-β1-induced EMT pathway and the emergence of gastric cancer stem cells (CSCs). Its eradication may prevent the carcinogenesis of gastric cancer by inhibiting these two pathways.

Accuracy of diagnostic tests for Helicobacter pylori in patients with peptic ulcer bleeding.

Background and Aims:  To assess the validity of biopsy‐based tests (histology, culture, and urease test) and serology in detecting current H. pylori infection for the peptic ulcer patients who had gastric bleeding.

Clinical Characteristics and Treatment Outcomes of 3 Subtypes of Achalasia According to the Chicago Classification in a Tertiary Institute in Korea

Background/Aims Achalasia is classified into 3 types according to the Chicago classification. The aim of this study was to investigate characteristics and treatment outcomes of 3 achalasia subtypes in Korean patients. Methods Fifty-five patients diagnosed with achalasia based on conventional or high-resolution esophageal manometry were consecutively enrolled. Their clinical characteristics, manometric, endoscopic and esophagographic findings and treatment responses were analyzed among the 3 subtypes of achalasia. Results Of 55 patients, 21 (38.2%) patients had type I, 28 (50.9%) patients had type II and 6 (10.9%) patients had type III. The median follow-up period was 22.4 (interquartile range, 3.6-67.4) months. Type III patients were older than type I and II patients (70.0 vs. 46.2 and 47.6 years, P = 0.023). The width of the esophagus in type I patients was wider with more frequent birds beak appearance on esophagogram than the other 2 types (P = 0.010 and 0.006, respectively). Of the 50 patients who received the evaluation for treatment response at 3 months, 7 patients (36.8% vs. 26.9%) were treated with pneumatic dilatation and 4 patients (21.1% vs. 15.4%) with laparoscopic Hellers myotomy in type I and II groups, respectively. The treatment responses of pneumatic dilatation and Hellers myotomy in type I group were 71.4 and 50.0% and in type II were 85.7 and 75.0%, respectively, and all 5 patients in type III group showed good response to medical therapy. Conclusions Clinical characteristics of 3 achalasia subtypes in Korean patients are consistent with other studies. Treatment outcomes are variable among 3 subtypes.

GenoType HelicoDR test in the determination of antimicrobial resistance of Helicobacter pylori in Korea

Abstract Objective. Antimicrobial resistance of Helicobacter pylori is most important factor in eradication success. GenoType HelicoDR test has been developed for rapid detection of antimicrobial resistance. The present study evaluated the clinical usefulness of GenoType HelicoDR test in Korea. Materials and methods. To detect 23S rRNA for clarithromycin resistance and gyrA mutations for fluoroquinolone resistance, both DNA sequencing after minimal inhibitory test (MIC) and GenoType HelicoDR test were performed in H. pylori isolates from the gastric mucosa of 101 patients. The eradication results of clarithromycin and moxifloxacin-containing triple therapy were evaluated by the 23S rRNA and gyrA mutations. Results. For 42 isolates with A2143G mutation by GenoType HelicoDR, 83.3% (35/42) of concordance rate was estimated with DNA sequencing method and 85.7% (36/42) for MIC test. For 43 isolates with N87K mutation by GenoType HelicoDR, 71.1% (31/43) of concordance rate was estimated with DNA sequencing and 88.4% (38/43) for MIC test. The sensitivity and specificity of GenoType HelicoDR test in determination of 23S rRNA mutation were 94.9% and 87.1%, and those of gyrA 98.2% and 80.0%. The sensitivity and specificity of GenoType HelicoDR test in determination of clarithromycin resistance based on MIC test were 55.0% and 80.0%, for fluoroquinolone 74.4% and 70.0%. Conclusion. GenoType HelicoDR test is useful to determine mutations responsible for clarithromycin or fluoroquinolone-containing eradication failure but has a limitation for the clinical applicability in determination of resistance.

Correlations Among Endoscopic, Histologic and Serologic Diagnoses for the Assessment of Atrophic Gastritis

Background: Atrophic gastritis is a precancerous condition, which can be diagnosed by several methods. However, there is no consensus for the standard method. The aim of this study was to evaluate the correlations among endoscopic, histologic, and serologic findings for the diagnosis of atrophic gastritis. Methods: From March 2003 to August 2013, a total of 2,558 subjects were enrolled. Endoscopic atrophic gastritis was graded by Kimura-Takemoto classification and histological atrophic gastritis was assessed by updated Sydney system. Serological assessment of atrophic gastritis was based on serum pepsinogen test. Results: The serum pepsinogen I/II ratio showed a significant decreasing nature when the extent of atrophy increased (R2=0.837, P<0.001) and the cut-off value for distinguishing between presence and absence of endoscopic atrophic gastritis was 3.2. The serum pepsinogen I and pepsinogen I/II ratio were significantly lower when the histological atrophic gastritis progressed and the cut-off value was 3.0 for a diagnosis of histological atrophic gastritis. A significant correlation between endoscopic and histological atrophic gastritis was noted and the sensitivity and specificity of endoscopic diagnosis were 65.9% and 58.0% for antrum, 71.3% and 53.7% for corpus, respectively. Conclusions: The endoscopic, histological, and serological atrophic gastritis showed relatively good correlations. However, as these three methods have a limitation, a multifactorial assessment might be needed to ameliorate the diagnostic accuracy of atrophic gastritis.

Characteristics of Helicobacter pylori-positive and Helicobacter pylori-negative gastric mucosa-associated lymphoid tissue lymphoma and their influence on clinical outcome.

To compare clinicopathologic and molecular characteristics of low‐grade gastric mucosa‐associated lymphoid tissue lymphoma depending on Helicobacter pylori positivity and to find out a predictive factor for unresponsiveness to Helicobacter pylori eradication therapy in Korea.

The Diagnostic Validity of Citric Acid-Free, High Dose 13C-Urea Breath Test After Helicobacter pylori Eradication in Korea

The 13C‐urea breath test (13C‐UBT) is a noninvasive method for diagnosing Helicobacter pylori (H. pylori) infection. The aims of this study were to evaluate the diagnostic validity of the 13C‐UBT cutoff value and to identify influencing clinical factors responsible for aberrant results.

Association of SLC6A4 5-HTTLPR and TRPV1 945G>C with functional dyspepsia in Korea.

The association of various genetic polymorphisms with functional dyspepsia (FD) has been suggested, but the results were still controversial. The aim of the present study was to assess the association of GNB3 825C>T, SLC6A4 5‐HTTLPR, ADRA2A‐1291C>G, CCK‐1R intron 779T>C, and TRPV1 945G>C polymorphisms with FD based on Rome III criteria in Korea.

Adequate Dextran Sodium Sulfate-induced Colitis Model in Mice and Effective Outcome Measurement Method.

Background: Dextran sodium sulfate (DSS)-induced colitis mouse model is used for research of inflammatory bowel disease. The aim of this study was to establish the adequate conditions for DSS mice model, and to find useful tool to measure inflammation. Methods: The 2.5% DSS was administered to six male C57BL/6 mice and 4% DSS to eight mice at 5 or 9 weeks of age. Each group was consisted of 6 mice with control group in which vehicle was administered instead of DSS. The mice were sacrificed on the 7th day after DSS or vehicle administration. Body weight, diarrhea, and hematochezia were recorded daily. Disease activity index (DAI) score which was composed of body weight change, diarrhea, and hematochezia was measured every day. Colon length was measured after sacrifice and colon mucosal level of interleukin 1 beta (IL-1β) was measured by ELISA assay. Histological score was compared between ascending and descending colon in the DSS group. Results: Colon length of five- and nine-week DSS group was significantly shorter than each control group but there was no statistical significance depending on DSS concentration or age. DAI score of 4% DSS group in nine-week was significantly higher than that five-week (P = 0.012) but there was no difference between 2.5% and 4% DSS group. The level of IL-1β in DSS mice was much higher than control group (P < 0.01), but there was no difference among several DSS groups. The histological score was higher in the descending colon than in the ascending colon but there was no statistical difference between each pair of DSS groups. Conclusions: The 4% DSS mice in nine-week was adequate for DSS-induced colitis model. DAI score was useful tool and descending colon was more appropriate site for histological evaluation of colitis than ascending colon.