Successful Endoscopic Submucosal Dissection Using Open Peroral Endoscopic Myotomy for Duodenal Neuroendocrine Tumor

Duodenal neuroendocrine tumors (NETs) are subepithelial tumors that are difficult to remove endoscopically, particularly when located just beyond the pylorus. This paper reports a case of a successful endoscopic submucosal dissection (ESD) using open gastric peroral endoscopic myotomy (POEM) for a remnant duodenal NET detected after endoscopic mucosal resection (EMR). A 67-year-old male presented with a 5 mm remnant duodenal NET close to the pylorus after EMR for a duodenal polypoid lesion performed four months earlier. Duodenal ESD was performed under conscious sedation using I-type and IT II knives. The tumor adhered to the fibrotic tissue, and the submucosal cushion was insufficient. Open gastric POEM was performed concurrently during ESD, resulting in the complete resection of the NET. This case suggests that while challenging, open gastric POEM can serve as a valuable technique for endoscopic resection in cases of early gastric cancer or duodenal masses located around the pylorus.

Evaluation of the Efficacy and Safety of DW1903 in Patients with Gastritis: A Randomized, Double-Blind, Noninferiority, Multicenter, Phase 3 study

Background/Aims

H2 receptor antagonists (H2RA) have been used to treat gastritis by inhibiting gastric acid. Proton pump inhibitors (PPIs) are more potent acid suppressants than H2RA. However, the efficacy and safety of low-dose PPI for treating gastritis remain unclear. The aim was to investigate the efficacy and safety of low-dose PPI for treating gastritis.

Methods

A double-blind, noninferiority, multicenter, phase 3 clinical trial randomly assigned 476 patients with endoscopic erosive gastritis to a group using esomeprazole 10 mg (DW1903) daily and a group using famotidine 20 mg (DW1903R1) daily for 2 weeks. The full-analysis set included 319 patients (DW1903, n=159; DW1903R1, n=160) and the per-protocol set included 298 patients (DW1903, n=147; DW1903R1, n=151). The primary endpoint (erosion improvement rate) and secondary endpoint (erosion and edema cure rates, improvement rates of hemorrhage, erythema, and symptoms) were assessed after the treatment. Adverse events were compared.

Results

According to the full-analysis set, the erosion improvement rates in the DW1903 and DW1903R1 groups were 59.8% and 58.8%, respectively. According to the per-protocol analysis, the erosion improvement rates in the DW1903 and DW1903R1 groups were 61.9% and 59.6%, respectively. Secondary endpoints were not significantly different between two groups except that the hemorrhagic improvement rate was higher in DW1903 with statistical tendency. The number of adverse events were not statistically different.

Conclusions

DW1903 of a low-dose PPI was not inferior to DW1903R1 of H2RA. Thus, lowdose PPI can be a novel option for treating gastritis (ClinicalTrials.gov Identifier: NCT05163756).

A Multicenter Survey of Percutaneous Endoscopic Gastrostomy in 2019 at Korean Medical Institutions

Background/Aims

: This study aimed to review the indications, methods, cooperation, complications, and outcomes of percutaneous endoscopic gastrostomy (PEG).

Methods

: Questionnaires were sent to 200 hospitals, of which 62 returned their questionnaires, with a response rate of approximately 30%. Descriptive statistics were calculated to analyze the responses to the questionnaires.

Results

: In 2019, a total of 1,052 PEGs were performed in 1,017 patients at 62 hospitals. The main group who underwent PEG was older adult patients with brain disease, particularly stroke. Nutritional supply was an important purpose of the PEG procedure. "The pull method" was the most commonly used for initial PEG insertion. The complications related to PEG were mostly mild, with leakage being the most common. Patients who underwent PEG procedures were primarily educated regarding the post-procedure management and complications related to PEG. Preoperative meetings were skipped at >50% of the institutions. Regarding the cooperation between the nutrition support team (NST) and the physician performing PEG, few endoscopists answered that they cooperated with NST before and after PEG. Moreover, the rate of NST certification obtained by physicians performing PEG and the frequency of attendance at NST-related conferences were relatively low.

Conclusions

: This study shows a similar trend to that found in the previous PEG guidelines. However, it covers new aspects, including team-based work for PEG procedure, nutrition support, and education for patients and guardians. Therefore, each medical institution needs to select an appropriate method considering the medical environment and doctor's abilities.

The efficacy of newly proposed gastric open peroral endoscopic myotomy (GO-POEM) in preventing post-endoscopic submucosal dissection stenosis: A comparison with non-GO-POEM group

Extensive endoscopic submucosal dissection (ESD) for gastric adenoma or early cancer can lead to post-ESD stenosis. This may cause a decrease in quality of life and an increase in medical issues. Therefore, this study examined the safety and effectiveness of gastric open peroral endoscopic myotomy (GO-POEM) in preventing stenosis following ESD. A retrospective investigation was carried out on 31 patients who underwent gastric ESD for > 75% of the lumen in the antrum or pylorus at the Presbyterian Medical Center in Korea between December 2004 and October 2022. The patients were divided into GO-POEM (n = 11) and non-GO-POEM groups (n = 20). The average age of the 31 patients was 73.23 years, and 18 were male. There were no differences in age, sex, location, gross findings, or procedure time between the 2 groups. In the GO-POEM group, only 1 patient (9 %) developed stenosis, compared to 11 patients (55 %) in the control group (P = .02). Multivariate analysis showed that the GO-POEM group had a significantly lower risk of post-ESD stenosis (P < .05). Stenosis symptoms resolved with a single endoscopic balloon dilatation (EBD) in 1 patient in the GO-POEM group. In contrast, 5 of 11 patients with stenosis in the non-GO-POEM group required a median of 2 EBD sessions (range, 1-8). GO-POEM may be an effective and reliable method for preventing stenosis post extensive gastric ESD. Further investigations are necessary to establish its efficacy and safety.

Case of Esophageal Actinomycosis Occurred after Endoscopic Mucosal Resection for Subepithelial Tumor

Esophageal actinomycosis is a rare, chronic granulomatous disease caused by Actinomyces species. Endoscopy and biopsy are essential for making a diagnosis. This paper reports a case of esophageal actinomycosis that developed after an endoscopic mucosal resection (EMR) for a subepithelial tumor (SET). A 74-year-old male patient had a 3 cm flat, smooth elevation in the esophagus without symptoms. The SET was partially resected, and histology revealed "nonspecific degenerated mesenchymal tissue". Three months later, the patient exhibited a persistently large ulceration at the EMR site, and a biopsy revealed actinomycosis. CT of the chest and abdomen revealed no abnormal findings. Ampicillin treatment was administered for six months, and the ulceration on the esophageal SET improved.

Underestimation of endoscopic size in large gastric epithelial neoplasms

BACKGROUND/AIMS

Endoscopic submucosal dissection (ESD) is an effective method for resecting gastric adenomas and adenocarcinomas. A significant discrepancy was observed between endoscopic and pathological sizes in samples obtained from patients undergoing ESD. This study elucidates the factors affecting size discrepancy after formalin fixation.

METHODS

The records of 64 patients with 69 lesions were analyzed, including 50 adenomas and 19 adenocarcinomas. Data on location, gross shape, histology, and size after fixation in formalin were collected.

RESULTS

The mean size of the resected specimen appeared to decrease after formalin fixation (37.5 mm prefixation vs. 35.8 mm postfixation, p<0.05). The mean long axis diameter of the lesions was 20.3±7.9 mm prefixation and 13.4±7.9 mm postfixation. Size differences in lesions smaller than 20 mm were significantly greater than those in lesions larger than 20 mm (7.6±5.6 mm vs. 2.5±5.8 mm, p<0.01). In multivariate analysis, a tumor size of ≥20 mm was found to be an independent factor affecting size postformalin fixation (p<0.05).

CONCLUSION

The endoscopic size of lesions before ESD may be underestimated in tumors larger than 20 mm in size. Therefore, increased attention must be paid during ESD to avoid instances of incomplete resection.

Long-term prognosis of curative endoscopic submucosal dissection for early colorectal cancer according to submucosal invasion: a multicenter cohort study

Background

Endoscopic submucosal dissection (ESD) can provide a high en bloc resection rate and has been widely applied as curative treatment for early colorectal cancer (ECC). However, surgical treatment is occasionally required, and reports on the long-term prognosis of ESD are insufficient. This study aimed to investigate the long-term outcomes of ECC removal by ESD, including local recurrence and metastasis.

Methods

This multicenter study was conducted retrospectively on 450 consecutive patients with ECC who were treated with ESD between November 2003 and December 2013. Clinical, pathological, and endoscopic data were collected to determine tumor depth, resection margin, lymphovascular invasion, and recurrence.

Results

The median follow-up period was 53.8 (12–138 months). The en bloc resection rate was 85.3% (384) and in intramucosal cancer being 84.1% and in superficial submucosal invasion (SM1) cancer being 89.8% (p = 0.158). The curative resection rate was 76.0% (n = 342), and there was no statistical difference between the two groups (77.3% vs. 71.4%, p = 0.231). The overall recurrence free survival rate (RFS) was 98.7% (444/450). In patients with curative resection, there was no statistically significant difference in RFS according to invasion depth (intramucosal: 99.3% vs. SM1: 97.1%, p = 0.248).

Conclusions

Patients with curatively resected ECC treated with ESD showed favorable long-term outcomes. Curatively resected SM1 cancer has a RFS similar to that of intramucosal cancer.

Endoscopic Ultrasonography-guided Gastrojejunostomy for Patients with Gastric Outlet Obstruction and Pyloric Metal Stent Dysfunction

A 52-year-old woman with a gastric outlet obstruction (GOO) caused by pyloric cancer underwent pyloric endoscopic self-expandable metal stent (SEMS) insertion. She presented with abdominal distension 40 days later. The SEMS was dysfunctional, and endoscopic ultrasound-guided gastrojejunostomy (EUS-GJ) was performed using an endoscopic nasobiliary drainage tube. A 16 mm×31 mm Niti-S ™ HOT SPAXUS™ (TaeWoong Medical, Gimpo, Korea) was inserted successfully between the stomach and the adjacent jejunum. After the procedure, the patient had a good oral intake for more than seven months. GOO is a mechanical obstructive condition caused by various benign and malignant conditions. Traditionally, surgical GJ and SEMS insertion have been used to treat GOOs. EUS-GJ is a feasible treatment option for patients with GOO and a pyloric metal stent dysfunction.

Safety and efficacy of prophylactic gastric open peroral endoscopic myotomy for prevention of post-ESD stenosis: A case series (with video)

OBJECTIVE

Endoscopic resection of over 3/4 of the lumen of the antrum or pylorus is a known risk factor for post-endoscopic submucosal dissection (ESD) stenosis. Local or systemic steroids may reduce the risk of stenosis, but their overall role in stenosis prevention remains controversial. We aimed to evaluate the efficacy and safety of prophylactic gastric open peroral endoscopic myotomy (GO-POEM) in preventing post-ESD stenosis.

METHODS

Ten patients who underwent GO-POEM during or immediately after ESD in the Presbyterian Medical Center between June 2017 and November 2020 were included. All patients underwent excision of over 3/4 of the lumen of the antrum or pylorus. GO-POEM was performed without submucosal tunneling.

RESULTS

Well-differentiated tubular adenocarcinoma, tubulovillous adenoma with high-grade dysplasia, and tubular adenoma with low-grade dysplasia were diagnosed in three, one, and six patients, respectively. GO-POEM was performed successfully in all the 10 patients. Stenosis could not be evaluated in one patient, whereas one of the remaining nine patients developed post-ESD stenosis. GO-POEM decreased the risk of post-ESD stenosis in the other eight patients. Two patients presented with intraprocedural bleeding, both of whom were managed endoscopically successfully.

CONCLUSIONS

Prophylactic GO-POEM may be a novel, effective and safe treatment modality for preventing post-ESD stenosis in the stomach. Well-designed, multicenter studies with large sample sizes are needed to confirm our results.

Predictive Factors for Differentiating Gastrointestinal Stromal Tumors from Leiomyomas Based on Endoscopic Ultrasonography Findings in Patients with Gastric Subepithelial Tumors: A Multicenter Retrospective Study

Background/Aims

The utility of endoscopic ultrasonography (EUS) for differentiating gastrointestinal stromal tumors (GISTs) and leiomyomas of the stomach is not well known. We aimed to evaluate the ability of EUS for differentiating gastric GISTs and leiomyomas.

Methods

We retrospectively reviewed the medical records of patients with histopathologically proven GISTs (n=274) and leiomyomas (n=87). In two consensus meetings, the inter-observer variability in the EUS image analysis was reduced. Using logistic regression analyses, we selected predictive factors and constructed a predictive model and nomogram for differentiating GISTs from leiomyomas. A receiver operating characteristic (ROC) curve analysis was performed to measure the discrimination performance in the development and internal validation sets.

Results

Multivariate analysis identified heterogeneity (odds ratio [OR], 9.48), non-cardia (OR, 19.11), and older age (OR, 1.06) as independent predictors of GISTs. The areas under the ROC curve of the predictive model using age, sex, and four EUS factors (homogeneity, location, anechoic spaces, and dimpling or ulcer) were 0.916 (sensitivity, 0.908; specificity, 0.793) and 0.904 (sensitivity, 0.908; specificity, 0.782) in the development and internal validation sets, respectively.

Conclusions

The predictive model and nomogram using age, sex and homogeneity, tumor location, presence of anechoic spaces, and presence of dimpling or ulcer on EUS may facilitate differentiation between GISTs and leiomyomas.

[Cannulation of the Portal Vein during Endoscopic Retrograde Cholangiopancreatography in a Patient with Choledocholithiasis]

Cannulation of the portal vein is a rare complication of ERCP. This paper reports a case of portal vein catheterization during ERCP in a patient with choledocholithiasis. A 62-year-old man was admitted to the Presbyterian Medical Center with right upper quadrant pain and jaundice. ERCP was performed under the suspicion of obstructive jaundice caused by a radiolucent stone. Bile duct cannulation using a pull-type papillotome was attempted, but it failed. After needle-knife fistulotomy, wire-guided cannulation was performed successfully, and 10 mL contrast was injected. On the other hand, the fluoroscopy image showed that the contrast medium disappeared very quickly. Pure blood was collected when the catheter was aspirated to identify the bile reflux, indicating possible cannulation of the portal vein. The procedure was terminated immediately and abdominal computed tomography showed air in the portal vein. One day after, a follow-up CT scan showed no air in the portal vein. The patient underwent repeated ERCP, and the common bile duct was cannulated. In most cases, isolated portal vein cannulation does not result in severe morbidity. However, it is important to aware of this rare complication so that no further invasive procedure is performed on the patient.

Time series analysis of delta neutrophil index as the predictor of sepsis in patients with acute poisoning

Delta neutrophil index (DNI), which reflects the fraction of immature granulocytes, is used to detect infection and sepsis from noninfectious conditions, but few studies have evaluated in the early stage of acute poisoning. This retrospective observational study was performed on acute poisoning patients who visited to the emergency department (ED) and were consecutively admitted in intensive care units over 18-month period. The serial DNI, conventional inflammatory biomarkers, and culture results were obtained in the ED and after admission. The outcomes were the identification of sepsis, bacteremia, and 30-day mortality. Of 166 patients (mean age, 56.0 years) in this cohort, 59 (35.5%) had sepsis and 29 (17.5%) had bacteremia. Initial and peak DNI fractions 24 h after ED admission were strong independent predictors of sepsis development. Analysis of the area under the curve according to multiple receiver operating characteristics showed that DNI had a higher capability to predict sepsis than other parameters (0.815 for DNI, 0.700 for procalcitonin, 0.681 for C-reactive protein, and 0.741 for white blood cell). Using multivariable logistic regression analysis, it was found that DNI was an independent predictor of sepsis (95% confidence interval (CI) of odds: 1.03-1.18) and bacteremia (95% CI: 1.01-1.14). Therefore, initial and serial measurement of DNI may serve as useful risk predictor for development of sepsis or bacteremia in acute poisoning.

Efficacy and Safety of AlbisD Compared With Omeprazole 20 mg in Patients With Non-erosive Reflux Disease: A Randomized, Open-label, Active-controlled, Pilot Study

Background/Aims

Proton pump inhibitors (PPIs) are frequently used to treat non-erosive reflux disease (NERD), but their effect is limited. It is not known whether a potential alternative, AlbisD, containing ranitidine hydrochloride, sucralfate hydrate, and tripotassium dicitrato bismuthate, is effective and safe in treating NERD. The aim of the study is to evaluate the efficacy and safety of AlbisD compared with omperazole in patients with NERD.

Methods

This was a multicenter, randomized, open-label, parallel-group, non-inferiority comparative study. A total of 126 patients with NERD were randomly allocated to either AlbisD twice daily or omeprazole 20 mg once daily for 4 weeks from February 2016 to August 2016. The study patients had histories of heartburn or regurgitation of moderate severity (> score 2) and a frequency of at least 2 episodes per week, and had no mucosal breaks of the esophagus on endoscopy. The primary efficacy variable was complete cure of heartburn at week 4. Secondary efficacy variables evaluating symptoms of heartburn and acid reflux as well as safety profiles were compared in the 2 groups at week 2 and 4 after treatment.

Results

A total of 113 patients completed the study (57 and 56 in AlbisD and omeprazole groups, respectively). The proportion of patients with complete cure of heartburn at week 4 was not significantly different between the AlbisD and omeprazole groups (35.1% vs 32.1% respectively, P = 0.740). There were no significant differences between the 2 groups in the any secondary variables including proportions of days without heartburn or acid reflux over 4 weeks (including daytime and nighttime). Adverse events were similarly reported in the 2 groups (7 [12.3%] vs 6 [10.7%]), and there were no serious adverse events.

Conclusions

The efficacy and safety of AlibsD in treating NERD patients are not inferior to those of omeprazole. Therefore, AlbisD can be an alternative to PPIs for NERD.

A risk-scoring model for the prediction of delayed bleeding after colorectal endoscopic submucosal dissection

BACKGROUND AND AIMS

Delayed bleeding is an important adverse event after colorectal endoscopic submucosal dissection (ESD). We aimed to investigate the incidence and risk factors of delayed bleeding after colorectal ESD and to develop a risk-scoring model for predicting delayed bleeding.

METHODS

This retrospective study was performed at 5 centers. The derivation and validation cohorts comprised 1189 patients from 1 center and 415 patients from the other 4 centers. We investigated the incidence and risk factors of delayed bleeding. Then, we developed a risk-scoring model for predicting delayed bleeding by using the data of the derivation cohort. We validated the scoring system in the validation cohort.

RESULTS

Delayed bleeding occurred in 34 patients (2.9%) in the derivation cohort. In multivariate analysis, the risk factors of delayed bleeding were tumor location in the rectosigmoid colon (odds ratio [OR], 6.49; 95% confidence interval [CI], 1.96-21.42; P = .002), large tumor (≥30 mm) (OR, 2.10; 95% CI, 1.01-4.40; P = .048), and use of antiplatelet agents except for aspirin alone (OR, 4.04; 95% CI, 1.44-11.30; P = .008). These 3 factors were incorporated into a risk-scoring model for prediction of delayed bleeding. As the score based on this system increased, the incidence of delayed bleeding increased in the validation cohort.

CONCLUSION

The risk-scoring model incorporating tumor location, tumor size, and use of antiplatelet agents can quantitatively predict the risk of delayed bleeding after colorectal ESD.

Seroprevalence of Helicobacter pylori in Korea: A multicenter, nationwide study conducted in 2015 and 2016

BACKGROUND

The Korean College of Helicobacter and Upper Gastrointestinal Research has studied Helicobacter pylori (H. pylori) prevalence since 1998 and found a dynamic change in its prevalence in Korea. The aim of this study was to determine the recent H. pylori prevalence rate and compare it with that of previous studies according to socioeconomic variables.

METHODS

We planned to enroll 4920 asymptomatic Korean adults from 21 centers according to the population distribution of seven geographic areas (Seoul, Gyeonggi, Gangwon, Chungcheong, Kyungsang, Cholla, and Jeju). We centrally collected serum and tested H. pylori serum IgG using a chemiluminescent enzyme immunoassay.

RESULTS

We analyzed 4917 samples (4917/4920 = 99.9%) from January 2015 to December 2016. After excluding equivocal serologic results, the H. pylori seropositivity rate was 51.0% (2414/4734). We verified a decrease in H. pylori seroprevalence compared with previous studies performed in 1998, 2005, and 2011 (P < .0001). The H. pylori seroprevalence rate differed by area: Cholla (59.5%), Chungcheong (59.2%), Kyungsang (55.1%), Jeju (54.4%), Gangwon (49.1%), Seoul (47.4%), and Gyeonggi (44.6%). The rate was higher in those older than 40 years (38.1% in those aged 30-39 years and 57.7% in those aged 40-49 years) and was lower in city residents than in noncity residents at all ages.

CONCLUSIONS

Helicobacter pylori seroprevalence in Korea is decreasing and may vary according to population characteristics. This trend should be considered to inform H. pylori-related policies.

Risk factors associated with adverse events during endoscopic ultrasound-guided tissue sampling

Background and aim

Endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) is commonly used to obtain tissue external to the gastrointestinal tract. EUS-FNA is relatively safe, but occasionally adverse events have been reported. There is scarcity of data on risk factors of adverse events. The aim of this study is to identify risk factors associated with EUS-FNA.

Methods

In this multicenter case-control study, we retrospectively reviewed 4,097 cases between 2009 and 2012 at 15 hospitals in Korea. Among the patients there were 104 cases (2.5%) who had adverse events of which 12 (0.29%) were severe. We matched 520 controls (1:5 ratios) stratified by hospital to analyze the potential risk factors.

Results

The most common adverse events were pancreatitis (45/104, 43.3%) and infection (46/104, 44.2%). Endoscopic retrograde cholangiopancreatography (ERCP) on the same day was a risk factor of all adverse events [OR = 2.41, 95% CI (1.41, 4.12)], pancreatitis [OR = 2.31, 95% CI (1.02, 5.25)], and infection [OR = 2.75, 95% CI (1.31, 5.78)]. More than 15 to-and-fro movements during puncture increased the risk of pancreatitis [OR = 2.30, 95% CI (1.11, 4.77)] and infection [OR = 3.65, 95% CI (1.55, 8.59)]. A higher number of punctures was positively correlated with pancreatitis [OR = 1.34, 95% CI (1.08, 1.67)] but negatively correlated with infection [OR = 0.66, 95% CI (0.48, 0.89)].

Conclusions

EUS-FNA is a safe procedure in which serious adverse events are rare. We define some risk factors of adverse events during EUS-FNA, including ERCP on the same day, a higher number of punctures, and more than 15 to-and-fro movements.

Evaluation of the Efficacy and Safety of DA-9601 versus Its New Formulation, DA-5204, in Patients with Gastritis: Phase III, Randomized, Double-Blind, Non-Inferiority Study

This study compared the efficacy of DA-9601 (Dong-A ST Co., Seoul, Korea) and its new formulation, DA-5204 (Dong-A ST Co.), for treating erosive gastritis. This phase III, randomized, multicenter, double-blind, non-inferiority trial randomly assigned 434 patients with endoscopically proven gastric mucosal erosions into two groups: DA-9601 3 times daily or DA-5,204 twice daily for 2 weeks. The final analysis included 421 patients (DA-5204, 209; DA-9601, 212). The primary endpoint (rate of effective gastric erosion healing) and secondary endpoints (cure rate of endoscopic erosion and gastrointestinal [GI] symptom relief) were assessed using endoscopy after the treatment. Drug-related adverse events (AEs), including GI symptoms, were also compared. At week 2, gastric healing rates with DA-5204 and DA-9601 were 42.1% (88/209) and 42.5% (90/212), respectively. The difference between the groups was -0.4% (95% confidence interval, -9.8% to 9.1%), which was above the non-inferiority margin of -14%. The cure rate of gastric erosion in both groups was 37.3%. The improvement rates of GI symptoms with DA-5204 and DA-9601 were 40.4% and 40.8%, respectively. There were no statistically significant differences between the two groups in both secondary endpoints. AEs were reported in 18 (8.4%) patients in the DA-5204 group and 19 (8.8%) in the DA-9601 group. Rates of AE were not different between the two groups. No serious AE or adverse drug reaction (ADR) occurred. These results demonstrate the non-inferiority of DA-5204 compared to DA-9601. DA-5204 is as effective as DA-9601 in the treatment of erosive gastritis. Registered randomized clinical trial at ClinicalTrials.gov (NCT02282670).

Neuroendocrine Tumors in the Stomach, Duodenum, and Pancreas Accompanied by Novel MEN1 Gene Mutation

Multiple endocrine neoplasia type 1 (MEN1) syndrome is a relatively rare disease, characterized by the occurrence of multiple endocrine tumors in the parathyroid and pituitary glands as well as the pancreas. Here, we report a case of MEN1 with neuroendocrine tumors (NETs) in the stomach, duodenum, and pancreas. A 53-year-old man visited our hospital to manage gastric NET. Five years prior to his visit, he had undergone surgery for incidental meningioma. His brother had pancreatic nodules and a history of surgery for adrenal adenoma. His brother's daughter also had pancreatic nodules, but had not undergone surgery. The lesion was treated by endoscopic submucosal dissection and diagnosed as a grade 1 NET. Another small NET was detected in the second duodenal portion, resected by endoscopic submucosal dissection, which was also diagnosed as a grade 1 NET. During evaluation, three nodules were detected in the pancreas, and no evidence of pituitary, parathyroid tumors, or metastasis was observed. After surgery, the pancreatic lesions were diagnosed as NETs, with the same immunohistochemical patterns as those of the stomach and duodenum. Genetic testing was performed, and a heterozygous mutation was detected in the MEN1 gene, which is located on 11q13.

Risk factors and management for pyloric stenosis occurred after endoscopic submucosal dissection adjacent to pylorus

Endoscopic submucosal dissection (ESD) has been widely accepted as a curative treatment for gastric neoplasm. Pyloric stenosis is a chronic complication that can be caused by ESD. The aim of this study is to clarify the risk factors and management for pyloric stenosis. From January 2004 to January 2014, a total of 126 patients who underwent ESD adjacent to pylorus were reviewed retrospectively. Pyloric mucosal defect was defined as when any resection margin of ESD was involved in the pyloric ring. Pyloric stenosis was defined as when a conventional endoscope could not be passed to the duodenum. Among the 126 patients, pyloric stenosis was identified in 9. In a univariate analysis, pyloric stenosis was more common in older patients (P < 0.05) and in lesions with resections over 75% of the pyloric ring circumference (P < 0.001). In a multivariate analysis, the factor that was associated with pyloric stenosis was the extent of the pyloric ring dissection (P < 0.001). Four of the 9 patients with pyloric stenosis had mild dyspepsia, and the others had gastric outlet obstruction symptoms. The 5 symptomatic patients underwent endoscopic balloon dilation (EBD), and the frequency of EBD was 1 to 8 times. The asymptomatic patients were treated conservatively. The incidence of pyloric stenosis was higher in lesions with resections over 75% of the pyloric ring circumference. Although EBD was an effective treatment for pyloric stenosis, conservative management was also helpful in patients who had mild symptoms.

An Intractable Caustic Esophageal Stricture Successfully Managed with Sequential Treatment Comprising Incision with an Insulated-Tip Knife, Balloon Dilation, and an Oral Steroid

Bougie or balloon dilation is a good short-term treatment for caustic esophageal strictures, although recurrence after dilation occurs in approximately 30% of these cases. Therefore, long-term treatment options are required in some cases, and endoscopic incisional therapy has been used for patients with an anastomotic stricture in the gastrointestinal tract. A 58-year-old woman presented with severe swallowing difficulty because of a caustic esophageal stricture, which was caused by accidental exposure to anhydrous acetic acid at infancy. She had undergone several previous bougie and balloon dilations but the stricture did not improve. We performed sequential treatment comprising incision with an insulated-tip knife, balloon dilation, and an oral steroid, which resulted in the patient’s symptoms markedly improving. Thus, we report this case of an intractable caustic esophageal stricture, which was successfully treated using combined endoscopic sequential treatment.

Prediction model and risk score for perforation in patients undergoing colorectal endoscopic submucosal dissection

BACKGROUND AND AIMS

Perforation is the adverse event of greatest concern during colorectal endoscopic submucosal dissection (ESD). Accurate risk prediction of perforation may enable prevention strategies and selection of the most efficient therapeutic option. This study aimed to develop and validate a risk prediction model for ESD-induced perforation.

METHODS

A multicenter cross-sectional study was performed on 2046 patients who underwent colorectal ESD at 9 Korean ESD Study Group-affiliated hospitals. The enrolled patients were randomly divided into either a derivation set or a validation set. In the derivation set, a prediction score was constructed to assess the risk of perforation using preoperative and procedural-related predictors selected via logistic regression. Discrimination and calibration of the prediction model was assessed using the validation set.

RESULTS

An ESD-induced perforation occurred in 135 patients (6.6%). In the derivation set, multivariate logistic regression identified endoscopist experience (≥50 ESDs: odds ratio [OR] = 0.59; 95% confidence interval [CI], 0.35-1.00), tumor size (+1-cm increments: OR = 1.39; 95% CI, 1.19-1.62), colonic location (OR = 2.20; 95% CI, 1.24-3.89), and submucosal fibrosis (OR = 2.00; 95% CI, 1.04-3.87) as predictive factors (C-statistic = 0.678; 95% CI, 0.617-0.739). In the validation set, the model showed good discrimination (C-statistic = 0.675; 95% CI, 0.615-0.735) and calibration (P = .635). When a simplified weighted scoring system based on the OR was used, risk of perforation ranged from 4.1% (95% CI, 2.8%-5.9%) in the low-risk group (score ≤4) to 11.6% (95% CI, 8.5%-15.6%) in the high-risk group (score >4).

CONCLUSIONS

This study developed and internally validated a score consisting of simple clinical factors to estimate the risk of colorectal ESD-induced perforation. This score can be used to identify patients at high risk before colorectal ESD.

Current Guidelines in the Management of Upper Gastrointestinal Subepithelial Tumors

Subepithelial tumors are frequently found in asymptomatic patients in Japan and Korea where cancer screening tests routinely include endoscopy. Most lesions are asymptomatic and clinically insignificant. However, carcinoid tumors, lymphomas, glomus tumor and gastrointestinal stromal tumors (GISTs) are malignant or have the potential to become malignant. Inflammation due to parasitic infestation by Anisakis and poorly differentiated adenocarcinomas in the stomach rarely present as subepithelial lesions. In contrast to the frequency of gastric GIST in the gastrointestinal system, they are uncommon in the duodenum and very rare in the esophagus. The prognosis of patients with GISTs in the stomach is relatively good compared with GISTs in other organs. Along with the location of the tumor, its size and mitotic count are major factors that determine the malignant potential of GIST. Small (<2 cm) asymptomatic GISTs usually have benign clinical course. GIST is the most common subepithelial tumor to occur in the stomach. Although various methods are employed to diagnose GISTs, the risk of GIST metastasis cannot be accurately predicted before lesions are completely resected. Recently, new endoscopic diagnostic methods and treatment techniques have been developed that allow the diagnosis and resection of lesions located in the muscularis propria, without any complications. These endoscopic methods have different indications depending on regions where they are performed.

The Role of Endosonography in the Staging of Gastrointestinal Cancers

Endosonography (EUS) enables the acquisition of clear images of the gastrointestinal tract wall and the surrounding structures. EUS enables much greater accuracy for staging decisions compared to computed tomography. Surgery for esophageal cancer has a high rate of morbidity and mortality, and it is important to decide on an appropriate treatment method through pre-surgical evaluation. Minimal invasive surgery is widely used for the treatment of gastrointestinal cancer, and endoscopic submucosal dissection is a safe treatment method for early cancer of the gastrointestinal tract that does not result in lymph node metastasis. EUS is essential for pre-surgical evaluation for all esophageal cancers. The use of EUS can effectively reduce unnecessary surgeries and thereby allow for appropriate treatment planning for patients. A number of different diagnostic modalities are available, but EUS is still the mainstay for pre-surgical evaluation of esophageal cancer. The role of EUS for early stomach cancer treatment as a tool for determining the need for endoscopic resection and for pre-surgical assessment is increasing.

Stricture occurring after endoscopic submucosal dissection for esophageal and gastric tumors

Endoscopic submucosal dissection (ESD) is a widely accepted treatment for early gastric and esophageal cancer. Compared to endoscopic mucosal resection, ESD has the advantage of enabling en bloc removal of tumors regardless of their size. However, ESD can result in a large artificial ulcer, which may lead to a considerable deformity. Circumferential mucosal defects of more than three-fourths the esophageal circumference, long longitudinal mucosal defects (>30 mm), and lesions in the upper esophagus are significant risk factors for the development of post-ESD strictures of the esophagus. In the stomach, a circumferential mucosal defects more than three-fourths in extent and longitudinal mucosal defects >5 cm are risk factors of post-ESD stricture. If scheduled early, regular endoscopic balloon dilation is effective in controlling and preventing post-ESD stricture. Moreover, intralesional steroid injections or oral steroids can achieve remission of dysphagia or reduce the need for repeated endoscopic balloon dilation. However, further study is needed to improve the prevention of stricture formation.

Lymph Node Metastases in Esophageal Carcinoma: An Endoscopist's View

One of the most important prognostic factors in esophageal carcinoma is lymph node metastasis, and in particular, the number of affected lymph nodes, which influences long-term outcomes. The esophageal lymphatic system is connected longitudinally and transversally; thus, the pattern of lymph node metastases is very complex. Early esophageal cancer frequently exhibits skipped metastasis, and minimal surgery using sentinel node navigation cannot be performed. In Korea, most esophageal cancer cases are squamous cell carcinoma (SCC), although the incidence of adenocarcinoma has started to increase recently. Most previous reports have failed to differentiate between SCC and adenocarcinoma, despite the fact that the Union for International Cancer Control (7th edition) and American Joint Committee on Cancer staging systems both consider these separately because they differ in cause, biology, lymph node metastasis, and outcome. Endoscopic tumor resection is an effective and safe treatment for lesions with no associated lymph node metastasis. Esophageal mucosal cancer confined to the lamina propria is an absolute indication for endoscopic resection, and a lesion that has invaded the muscularis mucosae can be cured by local resection if invasion to the lymphatic system has not occurred.

A case of Zollinger-Ellison syndrome in multiple endocrine neoplasia type 1 with urolithiasis as the initial presentation

Zollinger-Ellison syndrome (ZES) is characterized by gastrinoma and resultant hypergastrinemia, which leads to recurrent peptic ulcers. Because gastrinoma is the most common pancreatic endocrine tumor seen in multiple endocrine neoplasia type I (MEN 1), the possibility of gastrinoma should be investigated carefully when patients exhibit symptoms associated with hormonal changes. Ureteral stones associated with hyperparathyroidism in the early course of MEN 1 are known to be its most common clinical manifestation; appropriate evaluation and close follow-up of patients with hypercalcemic urolithiasis can lead to an early diagnosis of gastrinoma. We report a patient with ZES associated with MEN 1, and urolithiasis as the presenting entity. A 51-year-old man visited the emergency department with recurrent epigastric pain. He had a history of calcium urinary stone 3 years ago, and 2 years later he had 2 operations for multiple jejunal ulcer perforations; these surgeries were 9 months apart. He was taking intermittent courses of antiulcer medication. Multiple peripancreatic nodular masses, a hepatic metastasis, parathyroid hyperplasia, and a pituitary microadenoma were confirmed by multimodal imaging studies. We diagnosed ZES with MEN 1 and performed sequential surgical excision of the gastrinomas and the parathyroid adenoma. The patient received octreotide injection therapy and close follow-up.

Intramural gastric abscess caused by a toothpick presenting as a subepithelial tumor

In the present report, we describe an unusual case of an intramural gastric abscess caused by a foreign body, detected in the form of a subepithelial tumor. A 64-year-old woman was referred to our gastroenterology clinic for further evaluation of a gastric subepithelial tumor. The patient presented with a 1-month history of sustained dull epigastric pain. Esophagogastroduodenoscopy revealed an ill-demarcated, round, smooth, protruding lesion with a small central erosion on the great curvature of the proximal antrum. Endoscopic ultrasonography indicated the presence of an ovoid, heterogeneous, hypoechoic lesion with small echogenic foci located in the submucosa and muscularis propria layers. An abdominal computed tomography scan showed focal gastric wall thickening and regional lymph node enlargement. Endoscopic submucosal dissection was performed for definite diagnosis and management. Thus, we detected a toothpick and removed it using grasping forceps. The final diagnosis was an intramural gastric abscess caused by a toothpick.

Inhibition of mTOR affects protein stability of OGT

Autophagy regulates cellular homeostasis through degradation of aged or damaged subcellular organelles and components. Interestingly, autophagy-deficient beta cells, for example Atg7-mutant mice, exhibited hypoinsulinemia and hyperglycemia. Also, autophagy response is diminished in heart of diabetic mice. These results implied that autophagy and diabetes are closely connected and affect each other. Although protein O-GlcNAcylation is up-regulated in hyperglycemia and diabetes, and O-GlcNAcylated proteins play an important role in metabolism and nutrient sensing, little is known whether autophagy affects O-GlcNAc modification and vice versa. In this study, we suppressed the action of mTOR by treatment of mTOR catalytic inhibitors (PP242 and Torin1) to induce autophagic flux. Results showed a decrease in global O-GlcNAcylation, which is due to decreased OGT protein and increased OGA protein. Interestingly, knockdown of ATG genes or blocking of lysosomal degradation enhanced protein stability of OGT. In addition, when proteasomal inhibitor was treated together with mTOR inhibitor, protein level of OGT almost recovered to control level. These data suggest that mTOR inhibition is a more efficient way to reduce protein level of OGT rather than that of CHX treatment. We also showed that not only proteasomal degradation regulated OGT stability but autophagic degradation also affected OGT stability in part. We concluded that mTOR signaling regulates protein O-GlcNAc modification through adjustment of OGT stability.

Comparison of 22-gauge aspiration needle with 22-gauge biopsy needle in endoscopic ultrasonography-guided subepithelial tumor sampling

OBJECTIVE. Endoscopic ultrasonography (EUS)-guided fine-needle aspiration (EUS-FNA) may facilitate tissue sampling for histopathological diagnosis of subepithelial tumors (SETs) in the gastrointestinal (GI) tract. However, immunohistochemistry is not always feasible using EUS-FNA samples due to the low quality of specimens often obtained by aspiration. This study aimed to compare the use of 22-gauge (G) EUS-guided fine-needle biopsy (EUS-FNB) with 22G EUS-FNA for core sampling used for histopathological examination, including immunohistochemistry, in patients with GI SETs. METHODS. Twenty-eight patients with GI SETs ≥2 cm in size were prospectively enrolled at five university hospitals in Korea between January and June 2013. They were randomized to undergo either EUS-FNB or EUS-FNA. RESULTS. A total of 22 patients was finally analyzed in this study: 10 and 12 patients underwent EUS-FNA and EUS-FNB, respectively. Compared to the EUS-FNA group, the EUS-FNB group had a significantly lower median number of needle passes to obtain macroscopically optimal core samples (4 vs. 2, p = 0.025); higher yield rates of macroscopically and histologically optimal core samples with three needle passes (30% vs. 92%, p = 0.006; 20% vs. 75%, p = 0.010, respectively); and a higher diagnostic sufficiency rate (20% vs. 75%, p = 0.010). No technical difficulties were encountered in either group. CONCLUSIONS. This study shows that EUS-FNB has a better ability to obtain histological core samples and a higher diagnostic sufficiency rate than EUS-FNA and that EUS-FNB is a feasible, safe, and preferable modality for adequate core sampling for histopathological diagnosis of GI SETs.

Cloning and characterization of a flavonol synthase gene from Scutellaria baicalensis

Flavonols are the most abundant of all the flavonoids and play pivotal roles in a variety of plants. We isolated a cDNA clone encoding flavonol synthase from Scutellaria baicalensis (SbFLS). The SbFLS cDNA is 1011 bp long, encodes 336 amino acid residues, and belongs to a family of 2-oxoglutarate-dependent dioxygenases. The overall structure of SbFLS is very similar to that of Arabidopsis thaliana anthocyanidin synthase (AtANS), with a β jelly-roll fold surrounded by tens of short and long α-helices. SbFLS was constitutively expressed in the roots, stems, leaves, and flowers, with particularly high expression in the roots and flowers. SbFLS transcript levels in the roots were 376-, 70-, and 2.5-fold higher than in the leaves, stems, and flowers. The myricetin content was significantly higher than that of kaempferol and quercetin. Therefore, we suggest that SbFLS mediates flavonol formation in the different organs of S. baicalensis. Our study may contribute to the knowledge of the role of FLS in S. baicalensis.

Clinicopathological characteristics of synchronous and metachronous gastric neoplasms after endoscopic submucosal dissection

BACKGROUND/AIMS

Endoscopic submucosal dissection (ESD) has become accepted as a minimally invasive treatment for gastric neoplasms. However, the development of synchronous or metachronous gastric lesions after endoscopic resection has become a major problem. We investigated the characteristics of multiple gastric neoplasms in patients with early gastric cancer (EGC) or gastric adenoma after ESD.

METHODS

In total, 512 patients with EGC or gastric adenoma who had undergone ESD between January 2008 and December 2011 participated in this study. The incidence of and factors associated with synchronous and metachronous gastric tumors were investigated in this retrospective study.

RESULTS

In total, 66 patients (12.9%) had synchronous lesions, and 13 patients (2.5%) had metachronous lesions. Older (> 65 years) subjects had an increased risk of multiple gastric neoplasms (p = 0.012). About two-thirds of the multiple lesions were similar in macroscopic and histological type to the primary lesions. The median interval from the initial lesions to the diagnosis of metachronous lesions was 31 months. The annual incidence rate of metachronous lesions was approximately 3%.

CONCLUSIONS

We recommend careful follow-up in patients of advanced age (> 65 years) after initial ESD because multiple lesions could be detected in the remnant stomach. Annual surveillance might aid in the detection of metachronous lesions. Large-scale, multicenter, and longer prospective studies of appropriate surveillance programs are needed.

Cronkhite-Canada syndrome associated with serrated adenoma and malignant polyp: a case report and a literature review of 13 cronkhite-Canada syndrome cases in Korea

Cronkhite-Canada syndrome (CCS) is a rare nonfamilial polyposis syndrome characterized by epithelial disturbances both in the gastrointestinal tract and in the epidermis. The pathologic finding of the polyp is usually a hamartomatous polyp of the juvenile type; however, the possibility of serrated adenoma associated malignant neoplasm was reported in some Japanese cases. Up till now in South Korea, 13 CCS cases have been reported, but there was no case accompanied by the colon cancer. We report the first case of CCS associated with malignant colon polyp and serrated adenoma in Korea. A 72-year-old male patient who complained of diarrhea and weight loss was presented with both hands and feet nail dystrophy, hyperpigmentation, and alopecia. Endoscopic examination showed numerous hamartomatous polyps from the stomach to the colon. The pathologic results confirmed colon cancer and serrated adenoma. Helicobacter pylori eradication and prednisolone was used. Thus, the authors report this case along with a literature review.

The role of endoscopic ultrasonography in T staging: early gastric cancer and esophageal cancer

While a number of diagnostic methods have been developed, endoscopic ultrasound (EUS) still takes the most important role in the preoperative evaluation of esophageal cancer. EUS can detect lesions of all esophageal cancer and can accurately perform T staging. In a recent meta-analysis of EUS in esophageal cancer, the sensitivity and specificity of EUS on esophageal cancer were 81.6% and 99.4% in T1, 81.4% and 96.3% in T2, 91.4% and 94.4% in T3, and 92.4% and 97.4% in T4, respectively. The use of EUS can reduce unnecessary surgeries and lead to apply proper treatments to patients. The advance of endoscopic submucosal dissection have necessitated the presurgical detection of early cancer lesions without lymph node metastasis. Understanding the practical meanings of images shown by EUS is important to decide patients for whom endoscopic treatments can be effective. In early gastric cancer, EUS can accurately predict mucosal and SM1 (invasion into the submucosal layer of less than 500 µm from muscularis mucosa) lesions, which are considered as good indications for endoscopic treatments.

Waveform analysis of tremor may help to differentiate Parkinson's disease from drug-induced parkinsonism

In this study, we analyzed the waveform characteristics of resting tremor by accelerometer recordings in patients with drug-induced parkinsonism (DIP) and Parkinson's disease (PD). We prospectively recruited 12 patients with tremulous PD and 12 patients with DIP presenting with resting tremor. Tremor was recorded from the more affected side and was recorded twice for a 60 s period in each patient. Peak frequency, amplitude and all harmonic peaks were obtained, and the asymmetry of the decay of the autocorrelation function, third momentum and time-reversal invariance were also computed using a mathematical algorithm. Among the parameters used in the waveform analysis, the harmonic ratio, time-reversal invariance and asymmetric decay of the autocorrelation function were different between PD and DIP at a statistically significant level (all p < 0.01). The total harmonic peak power and third momentum in the time series were not significantly different. The clinical characteristics of DIP patients may be similar to those of PD patients in some cases, which makes the clinical differentiation between DIP and PD challenging. Our study shows that the identification of parameters reflecting waveform asymmetry might be helpful in differentiating between DIP and PD.

Multiple displacement amplification for preimplantation genetic diagnosis of fragile X syndrome

Preimplantation genetic diagnosis (PGD) has become an assisted reproductive technique for couples that have genetic risks. Despite the many advantages provided by PGD, there are several problems, including amplification failure, allele drop-out and amplification inefficiency. We evaluated multiple displacement amplification (MDA) for PGD of the fragile X syndrome. Whole genome amplification was performed using MDA. MDA products were subjected to fluorescent PCR of fragile X mental retardation-1 (FMR1) CGG repeats, amelogenin and two polymorphic markers. In the pre-clinical tests, the amplification rates of the FMR1 CGG repeat, DXS1215 and FRAXAC1 were 84.2, 87.5 and 75.0%, respectively, while the allele dropout rates were 31.3, 57.1 and 50.0%, respectively. In two PGD treatment cycles, 20 embryos among 30 embryos were successfully diagnosed as 10 normal embryos, four mutated embryos and six heterozygous carriers. Three healthy embryos were transferred to the uterus; however, no clinical pregnancy was achieved. Our data indicate that MDA and fluorescent PCR with four loci can be successfully applied to PGD for fragile X syndrome. Advanced methods for amplification of minuscule amounts of DNA could improve the sensitivity and reliability of PGD for complicated single gene disorders.

Technical issues and new devices of ESD of early gastric cancer

Endoscopic submucosal dissection (ESD) is a highly refined technique compared to conventional endoscopic mucosal resection. It enables complete resection of early gastric cancer (EGC) which has no possibility of lymph node metastasis. Indication for ESD of EGC generally entails early gastric cancer confined to the mucosa with well differentiated histology, though there are clinically suitable expanded criteria. As ESD requires specific skill and expertise, endoscopists need to be familiarized with basic methods and the use of special devices. The essence of the technique is to dissect the submucosal layer with direct vision and maintain the cutting plane above the underlying proper muscle layer. Although there are some differences in the detailed technical aspect, the cardinal method of ESD is now well established and standardized. Furthermore, research and development of new ESD devices that render more efficient, safe ESD are still in progress to improve the overall result of ESD on early gastric cancer.

Is glucose intolerance after pancreatitis related to pancreatic tissue damage?

Endoscopic retrograde pancreatography (ERP) was performed in 48 patients who had been hospitalized for pancreatitis. The findings were related to results of oral glucose tolerance tests. Patients with gross changes at ERP tended to have latent or manifest diabetes. In patients with latent or manifest diabetes, the increase in C-peptide after oral glucose was lower than in healthy subjects, while insulin sensitivity, estimated with euglycemic insulin clamp technique, was within the same range as in healthy subjects. It is concluded that gross changes of the pancreatic ducts after pancreatitis are often accompanied by widespread tissue damage leading to deficient B-cell function and decreased glucose tolerance.

Microbial community in biofilm on membrane surface of submerged MBR: effect of in-line cleaning chemical agent

The objective of this study was to investigate the change in microbial community pattern with the effect of cleaning agent using a quinone profile that is used for membrane in-line chemical cleaning in SMBR. The dominant quinone types of biofilm were ubiquinone (UQs)-8, -10, followed by menaquinone (MKs)-8(H4), -7 and UQ-9, but those of suspended microorganisms were UQ-8, UQ-10 followed by MKs-8(H4), -7 and -11. Both UQ and MK contents decreased with increasing NaCIO dosage and it seems that there is more resistance from UQ compared to MK. In addition, COD and DOC concentrations increased with increasing NaClO dosage up to 0.05 g-NaCIO/g-SS. The organic degradation performance of the microbial community in the presence of NaClO was impaired. The present study suggested that larger added amounts of NaClO caused an inhibition of organic degradation and cell lysis.

Investigation of biological and fouling characteristics of submerged membrane bioreactor process for wastewater treatment by model sensitivity analysis

In this study, a mathematical model for the submerged membrane bioreactor (SMBR) was developed. The activated sludge model No. 1 (ASM1) was modified to be suitable for describing the characteristics of the SMBR, and the resistance-in-series model was integrated into the ASM1 to describe membrane fouling. Using the newly developed model, the biological and fouling characteristics of the submerged membrane bioreactor process for wastewater treatment was investigated by sensitivity analysis. The sensitivity of effluent COD and nitrogen, TSS in the reactor and membrane flux with respect to each parameter (K(h), mu(H), K(S), K(NHH), K(NOH), b(H), Y(H), mu(A), K(NHA), b(A), Y(A), K(m) and alpha) was investigated by model simulation. As a result, the most important factors affecting membrane fouling were hydrolysis rate constant (K(h)) and cross-flow effect coefficient (K(m)). Heterotrophic yield coefficient (Y(H)) had a great influence on effluent quality. Effluent quality was also somewhat sensitive to K(h). Peculiar operating conditions of the SMBR such as long solids retention time (SRT), absolute retention of solids by membrane and high biomass concentration in bioreactor could explain these model simulation results. The model developed in this study would be very helpful to optimize operating conditions as well as design parameters for a SMBR system.

Microbial community structure of membrane fouling film in an intermittently and continuously aerated submerged membrane bioreactor treating domestic wastewater

There was an observable difference in microbial community structure between suspended microorganisms and membrane biofouling film in intermittently and continuously aerated SMBRs. The dominant quinone type of membrane biofouling film in an intermittently aerated SMBR was ubiquinone (UQs)-8, -10 followed by menaquinone (MKs)-8(H4) and -8(H2). But that of the continuously aerated SMBR was UQs-10, -8 followed by MKs-6 and -8(H4). The experimental results also showed that the conditions of an intermittently aerated SMBR may contribute to biofouling by Pseudomonas, Moraxella, Vibrio (quinone type UQ-8), Staphylococcus warneri (quinone type MK-7), Micrococcus sp. (quinone type MK-8(H2)) and Nocardia sp. (quinone type MK-8(H4)), but biofouling in a continuously aerated SMBR may be due to Paracoccus sp. (quinone type: UQ-10) and Flavobacterium species (quinone type: MK-6). The microbial diversities in the intermittently aerated SMBR were 10.9 and 9.4 for biofouling film and suspended microorganisms, respectively. For the continuously aerated SMBR, the results were 10.4 and 10.5 for biofouling film and suspended microorganisms, respectively.

Antibiotic selective pressure for the maintenance of antibiotic resistant genes in coliform bacteria isolated from the aquatic environment

Coliform bacteria isolated from the aquatic environment were investigated for antibiotic susceptibility and detailed structures of class 1 integrons. A high proportion of isolates were found to be resistant to sulfamethoxazole, aminoglycosides, and beta-lactams. The 750 (53.6%) isolates were resistant to one or more of the antibiotics tested out of 1,400 coliform bacteria. Based on the MIC of antibiotics and antibiogram, 150 isolates were selected and further studied for class 1 integrons. The intI1 gene was found in 36 (24.0%) of the 150 isolates. Twelve isolates carried the gene cassettes responsible for antibiotic resistance, while no gene cassettes were found in 24 isolates. Seven different genes, dfrA5, dfrA7, dfrA12, dfrA17, aaA2, aaA5, and aad(3'), were detected in gene cassettes. The dfrA and aad genes located on class 1 integrons were responsible for resistance to trimethoprim and aminoglycosides. The remaining 24 coliform bacteria had the incomplete or non-functional class 1 integrons. These results indicated that antibiotic selective pressures may play an important role to maintain gene cassettes of class 1 integrons and in the absence of sustained antibiotic pressures, such as the aquatic environment, coliform bacteria may carry empty or non-functional class 1 integrons.

Purulent pericarditis caused by group G streptococcus as an initial presentation of colon cancer

Bacterial pericarditis has been recognized as a rare disease since the development of antibiotics. Usually, the disease is associated with underlying conditions or a seeding of infection elsewhere to the pericardium. Here we describe a case of group G streptococcal pericarditis as an initial presentation of colon cancer. A 52-yr-old man was admitted because of dyspnea. An electrocardiogram showed a diffuse ST-segment elevation and a two-dimensional echocardiogram showed a large amount of pericardial effusion. A pericardiocentesis was done and purulent fluid was drained. Group G streptococci was cultured in pericardial fluid. The patient was treated with antibiotics and pericardiostomy with saline irrigation. A colonoscopy revealed a small mass with moderately differentiated adenocarcinoma in rectosigmoid colon. He underwent a mucosectomy and was recovered without any complication.

Creatine kinase B is a target molecule of reactive oxygen species in cervical cancer

Recently, a procedure for detecting ROS-sensitive proteins that contain active cysteine residues was devdoped. The method is based on the fact that biotin-conjugated iodoacetamide (BIAM) and ROS competitively and selectively react with the active cysteine residues in ROS-sensitive proteins. To investigate the role of ROS in cervical cancer, BIAM labeling on cytosolic proteins in normal and cancer tissues was performed, respectively. The BIAM labeling proteins are separated by 2-dimensional electrophoresis, and then identified by MALDI-TOF mass analysis. ROS-sensitive protein is identified as creatine kinase B containing cysteine residue in active center. Activity of creatine kinase B in normal tissue is higher than that of oxidized form in cervical cancer tissues. The result suggests that ROS play an important role in metabolic regulation in cervical cancer cells. However, molecular mechanisms that ROS and creatine kinase B are integrated into a physiological signal leading to the cellular transformation remain to be elucidated.

p21(WAF1) is associated with CDK2 and CDK4 protein during HL-60 cell differentiation by TPA treatment

TPA-treated HL-60 cells are mainly arrested in G1 by p21(WAF1) accumulation. We investigate the downstream changes following such accumulation. Increased p21(WAF1) is associated with CDK2 and CDK4. pRb is dephosphorylated in the presence of p21-CDK2/4 complexes, and the Rb-E2F1 complex increases after TPA treatment, whereas the Rb-HDAC1 complex decreases slightly. Our results suggest that increased p21(WAF1) is associated with CDK2/4, and that these complexes induce pRb dephosphorylation. In turn, hypophosphorylated pRb are mainly complexed with E2F1, but HDAC1 appears not to be a key component in this process.

Apoptotic cell death induced by Acinetobacter baumannii in epithelial cells through caspase-3 activation

Epithelial cell death induced by Acinetobacter baumannii infection was investigated using in vitro assays. Eight hours after live A. baumannii infection, HeLa cells exhibited detachment from the dish, rounding morphologies, high proportions of trypan blue-positive cells and extensive DNA breakdown with faint apoptotic banding, which is indicative of cells undergoing apoptosis. The enzymatic activity of caspase-3 was increased in cells as early as 2 h after infection. In addition, apoptosis of HeLa cells was induced by treatment with bacterial culture filtrates but not with formalin-killed bacteria. These results indicate that A. baumannii infection triggers apoptosis in HeLa cells through caspase-3 activation.