Since endoscopic papillary large balloon dilation (EPLBD) is used to treat benign disease and as a substitute for conventional methods, such as endoscopic sphincterotomy plus endoscopic mechanical lithotripsy, we should aim for zero mortality. This review defines EPLBD and suggests guidelines for its use based on a review of published articles and our large-scale multicenter retrospective review.

A common complication of pancreatitis is pseudocyst formation. Endoscopic drainage is a widely used treatment for pancreatic pseudocysts, and offers a definitive solution in approximately 75% of cases. Drainage-related complications may be related directly to the procedure or may occur later as stents and drains migrate or erode into adjacent structures. Procedure-related complications included bleeding, pancreatitis, and infection while stent-related complications may involve dislocation or clogging with subsequent infection. This report is the first description of the successful endoscopic removal of a migrated cystogastrostomy double pigtail stent through a pancreatico-duodenal fistula tract that developed more than six years after the stent was originally misplaced into a pseudocyst.

Phenotype-based functional genomic methods are useful for the identification of genes that are related to a particular biological function or disease. Essential to this approach is the ability to regulate the expression of selected genes. Artificial transcription factors (ATFs) are key molecular tools that selectively regulate gene expression in vivo. Here, we use an ATF library to identify genes that participate in rendering a cell resistant to the drug Taxol, a potent anti-cancer drug that binds to tubulin and inhibits cell division. The library, which encodes ATFs that activate (rather than inhibit) transcription, was introduced into a HeLa cell line, and Taxol-resistant cells were selected. After eight rounds of selection, we identified two ATFs that significantly increased the level of Taxol resistance (TR) in HeLa cells. Gene expression microarray experiments using these ATFs identified 37 co-regulated genes, including genes already known to participate in TR. This study demonstrates that ATF libraries can be used to induce phenotypic alterations in eukaryotic cells and then identify specific genes that are associated with the phenotype of choice.

The Drosophila pre-mRNA splicing factor B52 (SRp55) is essential for fly development, but splicing of RNAs of specific genes tested previously is normal in B52-null animals, presumably due to partial functional redundancy with other SR proteins. To identify B52-dependent splicing substrates in vivo, we selected genomic sequence fragments whose transcripts bind B52. Almost all of the corresponding genes having a known function encode either transcription factors or components of signal transduction pathways, with the B52- binding fragments located to not only exonic but also intronic regions. Some pre-mRNAs from these genes showed splicing defects in the B52-null mutant. These results indicate that B52 has unique functions in the removal of some introns during development, and plays a critical role in cellular regulatory networks.

The cancer stem cell (CSC) model posits the presence of a small number of CSCs in the heterogeneous cancer cell population that are ultimately responsible for tumor initiation, as well as cancer recurrence and metastasis. CSCs have been isolated from a variety of human cancers and are able to generate a hierarchical and heterogeneous cancer cell population. CSCs are also resistant to conventional chemo- and radio-therapies. Here we report that ionizing radiation can induce stem cell-like properties in heterogeneous cancer cells. Exposure of non-stem cancer cells to ionizing radiation enhanced spherogenesis, and this was accompanied by upregulation of the pluripotency genes Sox2 and Oct3/4. Knockdown of Sox2 or Oct3/4 inhibited radiation–induced spherogenesis and increased cellular sensitivity to radiation. These data demonstrate that ionizing radiation can activate stemness pathways in heterogeneous cancer cells, resulting in the enrichment of a CSC subpopulation with higher resistance to radiotherapy.

The development of reagents with high affinity and specificity to small molecules is crucial for the high-throughput detection of chemical compounds, such as toxicants or pollutants. Aptamers are short and single-stranded (ss) oligonucleotides able to recognize target molecules with high affinity. Here, we report the selection of ssDNA aptamers that bind to Bisphenol A (BPA), an environmental hormone. Using SELEX process, we isolated high affinity aptamers to BPA from a 1015 random library of 60 mer ssDNAs. The selected aptamers bound specifically to BPA, but not to structurally similar molecules, such as Bisphenol B with one methyl group difference, or 4,4′-Bisphenol with 2 methyl groups difference. Using these aptamers, we developed an aptamer-based sol–gel biochip and detected BPA dissolved in water. This novel BPA aptamer-based detection can be further applied to the universal and high-specificity detection of small molecules.

Background/Aims

The placement of self expandable metal stent (SEMS) is one of the palliative therapeutic options for patients with unresectable malignant biliary obstruction. The aim of this study was to compare the effectiveness of a covered SEMS versus the conventional plastic stent.

Methods

We retrospectively evaluated 44 patients with unresectable malignant biliary obstruction who were treated with a covered SEMS (21 patients) or a plastic stent (10 Fr, 23 patients). We analyzed the technical success rate, functional success rate, early complications, late complications, stent patency and survival rate.

Results

There was one case in the covered SEMS group that had failed technically, but was corrected successfully using lasso. Functional success rates were 90.5% in the covered SEMS group and 91.3% in the plastic stent group. There was no difference in early complications between the two groups. Median patency of the stent was significantly prolonged in patients who had a covered SEMS (233.6 days) compared with those who had a plastic stent (94.6 days) (p=0.006). During the follow-up period, stent occlusion occurred in 11 patients of the covered SEMS group. Mean survival showed no significant difference between the two groups (covered SEMS group, 236.9 days; plastic stent group, 222.3 days; p=0.182).

Conclusions

The patency of the covered SEMS was longer than that of the plastic stent and the lasso of the covered SEMS was available for repositioning of the stent.

Background/Aims

Rebleeding after endoscopic therapy for non-variceal upper gastrointestinal hemorrhage (NGIH) is the most important predictive factor of mortality. We evaluated the risk factors of rebleeding in patients undergoing endoscopic therapy for the NGIH.

Methods

Between January 2003 and January 2007, 554 bleeding events in 487 patients who underwent endoscopic therapy for NGIH were retrospectively enrolled. We reviewed the clinicoendoscopical characteristics of patients with rebleeding and compared them with those of patients without rebleeding.

Results

The incidence of rebleeding was 21.7% (n=120). In the multivariate analysis, initial hemoglobin level ≤9 g/dL (p=0.002; odds ratio [OR], 2.433), inexperienced endoscopist with less than 2 years of experience in therapeutic endoscopy (p=0.001; OR, 2.418), the need for more 15 cc of epinephrine (p=0.001; OR, 2.570), injection therapy compared to thermal and injection therapy (p=0.001; OR, 2.840), and comorbidity with chronic renal disease (p=0.004; OR, 2.908) or liver cirrhosis (p=0.010; OR, 2.870) were risk factors for rebleeding following endoscopic therapy.

Conclusions

Together with patients with low hemoglobin level at presentation, chronic renal disease, liver cirrhosis, the need for more 15 cc of epinephrine, or therapy done by inexperienced endoscopist were risk factors for the development of rebleeding.

Geographic atrophy (GA), an untreatable advanced form of age-related macular degeneration, results from retinal pigmented epithelium (RPE) cell death. Here we show that the microRNA (miRNA)-processing enzyme DICER1 is reduced in the RPE of humans with GA, and that conditional ablation of Dicer1, but not seven other miRNA-processing enzymes, induces RPE degeneration in mice. DICER1 knockdown induces accumulation of Alu RNA in human RPE cells and Alu-like B1 and B2 RNAs in mouse RPE. Alu RNA is increased in the RPE of humans with GA, and this pathogenic RNA induces human RPE cytotoxicity and RPE degeneration in mice. Antisense oligonucleotides targeting Alu/B1/B2 RNAs prevent DICER1 depletion-induced RPE degeneration despite global miRNA downregulation. DICER1 degrades Alu RNA, and this digested Alu RNA cannot induce RPE degeneration in mice. These findings reveal a miRNA-independent cell survival function for DICER1 involving retrotransposon transcript degradation, show that Alu RNA can directly cause human pathology, and identify new targets for a major cause of blindness.

Since the discovery of double-stranded (ds) RNA-mediated RNA interference (RNAi) phenomenon in Caenorhabditis elegans, specific gene silencing based upon RNAi mechanism has become a novel biomedical tool that has extended our understanding of cell biology and opened the door to an innovative class of therapeutic agents. To silence genes in mammalian cells, short dsRNA referred to as small interfering RNA (siRNA) is used as an RNAi trigger to avoid nonspecific interferon responses induced by long dsRNAs. An early structure–activity relationship study performed in Drosophila melanogaster embryonic extract suggested the existence of strict siRNA structural design rules to achieve optimal gene silencing. These rules include the presence of a 3′ overhang, a fixed duplex length, and structural symmetry, which defined the structure of a classical siRNA. However, several recent studies performed in mammalian cells have hinted that the gene silencing siRNA structure could be much more flexible than that originally proposed. Moreover, many of the nonclassical siRNA structural variants reported improved features over the classical siRNAs, including increased potency, reduced nonspecific responses, and enhanced cellular delivery. In this review, we summarize the recent progress in the development of gene silencing siRNA structural variants and discuss these in light of the flexibility of the RNAi machinery in mammalian cells.

Background

Endoscopic papillary large balloon dilatation (EPLBD) after endoscopic sphincterotomy (EST) has recently become widely used for common bile duct (CBD) stone removal, but many clinicians remain concerned about post-procedural pancreatitis with increasing the balloon size to over 15 mm.

Aims

We aimed to evaluate the safety and efficacy of EPLBD with a relatively large balloon (15–20 mm) after EST and to evaluate the factors related to post-EPLBD pancreatitis.

Methods

A retrospective review was undertaken of the endoscopic database of 101 patients with CBD stones who underwent EPLBD using a larger balloon size of over 15 mm (15–20 mm). Clinical parameters, endoscopic data, and outcomes were analyzed.

Results

The mean age of the subjects was 69 years. All patients had a dilated CBD of over 11 mm (mean = 22.6 mm). The mean size of balloon used in EPLBD was 17.1 ± 1.9 mm (range 15–20 mm). Mechanical lithotripsy was required in seven patients (6.9%). The rate of complete stone removal in the first session was 92.1%. Post-procedural pancreatitis developed in five cases (5.4%), but none were graded as severe. The smaller dilatation of the CBD, longer cannulation time, and longer time for stone removal were associated with post-procedural pancreatitis, but larger size of balloon did not affect the development of post-EPLBD pancreatitis.

Conclusions

EPLBD with a large balloon of over 15 mm with EST is an effective and safe procedure with a very low probability of severe post-procedural pancreatitis. Post-EPLBD pancreatitis was not associated with larger balloon size, but was associated with longer procedure time and smaller dilatation of the CBD.

Background/Aims

Biliary stricture is the most common and important complication after right-lobe living-donor liver transplantation (RL-LDLT) with duct-to-duct biliary anastomosis. This study evaluated the efficacy and long-term outcome of endoscopic treatment for biliary stricture after LDLT, with the aim of identifying the factors that influence the outcome.

Methods

Three hundred and thirty-nine adults received RL-LDLTs with duct-to-duct biliary anastomosis between January 2000 and May 2008 at Kangnam St. Mary's Hospital. Endoscopic retrograde cholangiography (ERC) was performed in 113 patients who had biliary stricture after LDLT. We evaluated the incidence of post-LDLT biliary stricture and the long-term outcome of endoscopic treatment for biliary stricture. The factors related to the outcome were analyzed.

Results

Biliary strictures developed in 121 (35.7%) patients, 95 (78.5%) of them within 1 year of surgery. The mean number of ERCs performed per patient was 3.2 (range, 1 to 11). The serum biochemical markers decreased significantly after ERC (p<0.001). Stent insertion or stricture dilatation during ERC was successful in 90 (79.6%) patients. After a median follow-up period of 33 months from the first successful treatment with ERC, 48 (42.5%) patients achieved treatment success and 12 (10.6%) patients remained under treatment. The factors related to the outcome of endoscopic treatment were nonanastomotic stricture and stenosis of the hepatic artery (p=0.016).

Conclusions

Endoscopic treatment is efficacious and has an acceptable long-term outcome in the management of biliary strictures related to RL-LDLT with duct-to-duct biliary anastomosis. Nonanastomotic stricture and stenosis of the hepatic artery are correlated with a worse outcome of endoscopic treatment.

Background

Basic region-leucine zipper (bZIP) proteins are a class of transcription factors (TFs) that play diverse roles in eukaryotes. Malfunctions in these proteins lead to cancer and various other diseases. For detailed characterization of these TFs, further public resources are required.

Description

We constructed a database, designated bZIPDB, containing information on 49 human bZIP TFs, by means of automated literature collection and manual curation. bZIPDB aims to provide public data required for deciphering the gene regulatory network of the human bZIP family, e.g., evaluation or reference information for the identification of regulatory modules. The resources provided by bZIPDB include (1) protein interaction data including direct binding, phosphorylation and functional associations between bZIP TFs and other cellular proteins, along with other types of interactions, (2) bZIP TF-target gene relationships, (3) the cellular network of bZIP TFs in particular cell lines, and (4) gene information and ontology. In the current version of the database, 721 protein interactions and 560 TF-target gene relationships are recorded. bZIPDB is annually updated for the newly discovered information.

Conclusion

bZIPDB is a repository of detailed regulatory information for human bZIP TFs that is collected and processed from the literature, designed to facilitate analysis of this protein family. bZIPDB is available for public use at .

Capecitabine and gemcitabine are used in the treatment of a variety of solid tumors including pancreatic and biliary tract carcinomas. The authors evaluated survival, response, and toxicity associated with using a combination of capecitabine and gemcitabine to treat patients with unresectable or metastatic gallbladder adenocarcinoma (GBC). Eligible patients had histologically- or cytologically-confirmed GBC, no prior systemic therapy with capecitabine or gemcitabine, Karnofsky Performance Status 70%, serum total bilirubin up to three times normal, and measurable disease. Treatment consisted of gemcitabine 1000 mg/m2 IV on Days 1 and 8 concurrent with administration of capecitabine 1000 mg/m2 PO BID on Days 1 through 14, on a 3-week cycle. Tumor response was assessed by the response evaluation criteria in solid tumors (RECIST criteria) and survival was calculated from initiation of CapGem therapy. A total of 24 patients were enrolled. Median age at the time of diagnosis was 62 years (range, 41-78 years). Fourteen patients had undergone prior surgery. Results showed that eight patients achieved partial response (33%) with an additional 10 patients achieving stable disease (42%). The overall median time to disease progression was 6.0 months (95% CI, 3.8-8.1 months) and overall survival was 16 months (95% CI, 13.8-18.3 months). The one-year survival rate was 58%. No Grade 4 toxicity was seen. Transient Grade 3 neutropenia/thrombocytopenia and manageable nausea, hand-foot syndrome and anorexia were the most common toxicities. Our study shows that CapGem is an active and well-tolerated chemotherapy regimen in patients with advanced GBC.

Rifaximin has been reported to be effective for the treatment of hepatic encephalopathy (HE) in Europe. However, it is unknown whether Rifaximin is effective for the treatment of HE in Koreans, therefore we conducted a open-label prospective randomized study to evaluate the efficacy of rifaximin versus lactulose in Korean patients. Fifty-four patients with liver cirrhosis and hepatic encephalopathy were enrolled. Thirty-two patients were randomized to receive rifaximin and 22 to receive lactulose both over a 7-day periods. Before and at the end of treatment, gradation of blood ammonia, flapping tremor, mental status, number connection test (NCT) were performed and estimation of HE indexes determined. Both rifaximin and lactulose were effective in the majority of patients (84.4% and 95.4%, respectively, p=0.315). Blood NH3, flapping tremor, mental status, and NCT was significantly improved by rifaximin and lactulose, and the posttreatment levels of these measures were similar for the rifaximin and lactulose-treated groups, as was the HE index (rifaximin group (10.0→4.2, p=0.000); lactulose group (11.3→5.0, p=0.000)). One patient treated with rifaximin complained of abdominal pain, which was easily controlled. There was no episode of renal function impairment in either treatment group. Rifaximin proved to be as safe and as effective as lactulose for the treatment of Korean patients with hepatic encephalopathy.

Esophageal leiomyoma derived from the muscularis mucosae (MM) is a rare condition, and the optimal modality for diagnosis and treatment is controversial. Endoscopic ultrasonography can provide an accurate image of esophageal layer structure, providing information on lesion suitability for potential endoscopic therapy. We attempted to investigate the diagnostic value of a transendoscopic balloon-tipped miniature ultrasonic endoprobe for small esophageal leiomyomas derived from MM. We resected 7 small esophageal leiomyomas derived from MM by endoscopic mucosal resection (EMR), all of which were diagnosed by a balloon-tipped endoprobe. The endosonographic and pathologic features of 7 cases of small esophageal leiomyomas derived from MM were compared. The balloon-tipped endoprobe clearly showed all 7 small esophageal leiomyomas derived from MM, even those under 5 mm in size (smallest lesion, 3.0 mm). The endosonographic characteristics of small esophageal leiomyomas derived from MM were a hypoechoic mass with smooth, regular, and a well-defined outer margin and homogenous inner echogram arising from the second hypoechoic layer. Complete resections were possible in all 7 cases by EMR without any complications. Tumor size was 3.0 - 13.5 mm (mean 7.8 mm) in maximum diameter. In all cases, endosonographic findings by endoprobe were exactly concordant with pathologic finding in determining the tumors depth in the esophageal wall, tissue origin and characteristics, growth pattern, and size. We detail the balloon-tipped endoprobe is a simple, convenient, and very useful in making accurate diagnosis of small esophageal leiomyomas derived from the MM and the appropriate applications of EMR.

AIM: To investigate prevalence of Clonorchis sinensis in patients with gastrointestinal symptoms, and the relation of the infection to hepatobiliary diseases in 26 hospitals in Korea.

METHODS: Consecutive patients who had been admitted to the Division of Gastroenterology with gastrointestinal symptoms were enrolled from March to April 2005. Of those who had been diagnosed with clonorchiasis, epidemiology and correlation between infection and hepatobiliary diseases were surveyed by questionnaire.

RESULTS: Of 3080 patients with gastrointestinal diseases, 396 (12.9%) had clonorchiasis and 1140 patients (37.2%) had a history of eating raw freshwater fish. Of those with a history of raw freshwater fish ingestion, 238 (20.9%) patients had clonorchiasis. Cholangiocarcinoma was more prevalent in C. sinensis-infected patients than non-infected patients [34/396 (8.6%) vs 145/2684 (5.4%), P = 0.015]. Cholangiocarcinoma and clonorchiasis showed statistically significant positive cross-relation (P = 0.008). Choledocholithiasis, cholecystolithiasis, cholangitis, hepatocellular carcinoma, and biliary pancreatitis did not correlate with clonorchiasis.

CONCLUSION: Infection rate of clonorchiasis was still high in patients with gastrointestinal diseases in Korea, and has not decreased very much during the last two decades. Cholangiocarcinoma was related to clonorchiasis, which suggested an etiological role for the parasite.