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Objectives. Radiofrequency ablation (RFA) has replaced photodynamic therapy for premalignant and malignant lesions of the esophagus. However, there is limited experience in the bile duct. The objective of this pilot study was to assess the safety and efficacy of RFA in malignant biliary strictures. Methods: Twenty patients with unresectable malignant biliary strictures underwent RFA with stenting between June 2010 and July 2012. Diameters of the stricture before and after RFA, immediate and 30 day complications and stent patency were recorded prospectively. Results. A total of 25 strictures were treated. Mean stricture length treated was 15.2 mm (SD = 8.7 mm, Range = 3.5–33 mm). Mean stricture diameter before RFA was 1.7 mm (SD = 0.9 mm, Range = 0.5–3.4 mm) while the mean diameter after RFA was 5.2 mm (SD = 2 mm, Range = 2.6–9 mm). There was a significant increase of 3.5 mm (t = 10.8, DF = 24, P value = <.0001) in the bile duct diameter post RFA. Five patients presented with pain after the procedure, but only one developed mild post-ERCP pancreatitis and cholecystitis. Conclusions: Radiofrequency ablation can be a safe palliation option for unresectable malignant biliary strictures. A multicenter randomized controlled trial is required to confirm the long term benefits of RFA and stenting compared to stenting alone.

Backgrounds. Limited effective palliative treatments exist for pancreatic cancer which includes surgery or chemotherapy. Radiofrequency ablation (RFA) uses high frequency alternating current to ablate diseased tissue and has been used to treat various tumors. In this study, we evaluated a prototype probe adjusted to the EUS-needle to perform EUS-RFA to permit coagulative necrosis in the pancreas. Methods. Five Yucatan pigs underwent EUS-guided radiofrequency ablation of the head of their pancreas. Using an EUS-needle, RFA was applied with 6 mm and then 10 mm of the probe exposed at specific wattage for preset durations. Results. Only one pig showed moderate levels of pancreatitis (20% proximal pancreatitis). The other animals showed much lower areas of tissue damage. In 3 of the 5 pigs, the proximal pancreas showed greater levels of tissue injury than the distal pancreas, consistent with the proximity of the tissue to the procedure site. In 1 pig, both proximal and distal pancreas showed minimal pancreatitis (1%). There was minimal evidence of fat necrosis in intra-pancreatic and/or extra-pancreatic adipose tissue. Conclusion. EUS-guided RFA of the pancreatic head with the monopolar probe through a 19-gauge needle was well tolerated in 5 Yucatan pigs and with minimal amount of pancreatitis.

Bacterial leaf streak (BLS) of wheat and barley is an economically important disease in most small grain growing regions worldwide and is primarily caused by Xanthomonas translucens pv. undulosa and X. translucens pv. translucens, respectively. BLS is generally described as a seedborne disease, however, the pathogen may overwinter in a range of host plants. X. translucens pv. undulosa has a broad host range and infects several cultivated small grains along with perennial and annual weedy grasses. The advancement of high-throughput sequencing has facilitated a growing database of whole genome sequences of X. translucens strains. In this study we sequenced and assembled the complete genomes of five X. translucens pv. undulosa strains originating from wheat, cultivated wild rice, and three weedy grasses. This study details the first X. translucens pv. undulosa genomes isolated from non-wheat hosts. We compared these genomes to publicly available strains and found all the X. translucens pv. undulosa were closely related, sharing ≥99.25% average nucleotide identity, but non-clonal. Genome structures and the presence of Type III secreted effectors varied among strains, but no unique features were identified to differentiate those originating from wheat and non-wheat hosts. Despite being considered a seedborne disease, the records of seed transmission are circumstantial and/or inconsistent. In this study, wheat and barley seed were inoculated with a rifampicin-resistant strain of X. translucens pv. undulosa and X. translucens pv. translucens, respectively, with the aim of tracking the movement of the pathogens from the host’s seed into developing plant tissues. Rifampicin-resistant strains were recovered from both wheat and barley at multiple growth stages through maturity. Under mist-irrigated field conditions, pathogen recovery occurred from all sampled tissue from the third leaf to spikes at soft dough, in both hosts. Recovery was reduced under dryland conditions, especially from wheat. Quantitative PCR can be used to detect and quantify X. translucens from wheat and barley seed but does not distinguish living cells from dead cells. We tested a protocol for conducting a viability PCR assay, which quantifies viable X. translucens cells, and then used the assay to examine pathogen populations on different wheat seed lots. We found that the viable populations of X. translucens cells on wheat seed decreased over one year, although the final concentration of viable cells exceeded 1 X 103 CFU/g, the reported threshold needed to cause BLS. The genome, transmission, and quantification studies of X. translucens contribute to our understanding of pathogen diversity and BLS epidemiology and may inform the development of management strategies.

Bacterial leaf streak (BLS) of wheat, caused by Xanthomonas translucens pv. undulosa, has been prevalent in Minnesota wheat fields for the past decade. Infested seed and crop debris can serve as inoculum for subsequent crops. Weeds are also considered a potential inoculum source, but little is known about specific pathovars and genetic diversity among strains of X. translucens from these different hosts. The objectives of this study were to isolate X. translucens from poaceous weeds and cultivated wild rice in Minnesota, determine pathogenicity of these strains on wheat and barley, assess phylogenetic relationships and genetic diversity of strains using multilocus sequence analysis (MLSA) and typing (MLST) of four housekeeping genes (rpoD, dnaK, fyuA, and gyrB), and evaluate the efficacy of loop-mediated isothermal amplification (LAMP) assays designed to identify X. translucens pathovars that cause BLS on small grains. Bacteria were isolated from 157 plant samples, representing 12 poaceous hosts collected in and around commercial fields of wheat and wild rice. Strains exhibiting characteristic colony morphology on Wilbrink’s medium were purified and evaluated further. The majority (87/134) of Xanthomonas strains were predicted to be X. translucens by 16S rDNA sequencing. A subset (51) of the strains predicted to be X. translucens were infiltrated into leaves of wheat and barley seedlings and found to cause disease. Eight of these strains were also tested in the field and likewise caused disease on wheat and barley. Phylogenies from MLSA show that strains from weedy grasses and wild rice are closely related to known X. translucens pathovars, most commonly X. translucens pv. undulosa. The findings suggest that poaceous weeds and cultivated wild rice have potential to serve as reservoirs of inoculum for the bacterial pathogen inciting BLS of wheat.

Background Partially covered metal stents (PCMS) have been increasingly used for both malignant and benign biliary indications. This study reports their complications and subsequent management. Methods Over 5 years, all patients receiving biliary PCMS were followed prospectively until stent-related dysfunction or death. Data were analyzed for the following variables: primary disease, time until revision, and type and reason for revision. Results PCMS were placed in 396 patients (247 with malignant biliary strictures and 149 with benign biliary disease). Complications were observed in 70 patients (18%), occurring a mean time following placement of 159 days. Duodenal migration occurred in 27 cases (6.8%), while proximal migration occurred in 9 cases (2.3%). Cholecystitis was documented in 13 cases (3.3%). There were six cases of stent occlusion due to debris or sludge (1.6%), four cases of pancreatitis (1%), four cases of tumor overgrowth (1%), three cases of benign stenosis in the uncovered portion of the PCMS (0.8%), two cases of abdominal pain (0.5%), one case of an infected biloma (0.3%), and one case of a liver abscess (0.3%). Conclusions Major complications associated with PCMS placement include migration and cholecystitis. Their management includes endoscopic revision, cholecystectomy, and gallbladder drainage. Further improvements in the structure and composition of PCMS may prevent these complications.

Background Roux-en-Y gastric bypass (RYGB) surgery is one of the most commonly performed bariatric surgeries in the United States. Patients with prior RYGB are not amenable to conventional endoscopic retrograde cholangiopancreaticography (ERCP). Surgical gastrostomy (SG) tube placement enables transgastrostomy ERCP (TG-ERCP). Materials and Methods Eleven patients with RYGB anatomy received open Stamm gastrostomy after which the tract was then allowed to mature for an average of 45 days before therapeutic TG-ERCP. The success rate and procedure-related complications of both gastrostomy and ERCP were assessed. Results TG-ERCP was performed on eleven patients (median age 52 years, range 37–61 years) with prior RYGB and pancreatobiliary diseases. Indications for ERCP in these patients included suspected gallstone pancreatitis ( n  = 4), ampullary/biliary strictures ( n  = 5), pancreas divisum ( n  = 1), and common bile duct clipping as a result of RYGB surgery ( n  = 1). Two individuals developed post surgical complications with stomal-related infections. TG-ERCP with therapeutic intervention was successfully performed in all patients. Intervention included stone extractions ( n  = 11), biliary stricture dilation ( n  = 11), biliary sphincterotomy ( n  = 11), biliary ( n  = 3) and pancreatic ( n  = 1) stent placement, ampullary biopsies ( n  = 3), choledochoscopy ( n  = 1), and pseudocyst drainage ( n  = 1). Complications included post-ERCP pancreatitis ( n  = 2), post-sphincterotomy bleeding ( n  = 1), gastrostomy site bleed ( n  = 1), and gastric perforation ( n  = 1). The total number of ERCP sessions for the eleven patients was 15 (1 or 2 per patient). Median follow-up was 42 days (range 7–123 days). Conclusion Surgical open gastrostomy followed by TG-ERCP enables therapeutic intervention but is associated with significant complications.

Background Current management of malignant gastric outlet obstruction (GOO) includes surgical diversion or enteral stent placement for unresectable cancer. We analyzed the long-term results, predictive factors of outcomes, and complications associated with enteral stents with focus on their management. Methods Between 1997 and 2007, 46 patients with malignant GOO underwent placement of self-expandable metal stents (SEMS) for palliation. Patients were captured prospectively after 2001 and followed until complication or death. Patency, management of complications, and long-term survival were analyzed. Results Forty-six patients had a mean survival of 152 ± 235 days and a mean SEMS patency rate of 111 ± 220 days. SEMS patency rates of 98%, 74%, and 57% at 1, 3, and 6 months were seen. Thirteen patients presented with obstruction and included two SEMS migration, two early occlusion, one fracture, four malignant ingrowth, and four with delayed clinical failure. Interventions included seven endoscopic revisions with three SEMS replacements. Six had percutaneous endoscopic gastrostomy with jejunal arm placed. Two patients eventually underwent surgical bypass. Two patients required surgery for complications including delayed duodenal perforation and aortoenteric fistula. Conclusions SEMS effectively palliate gastric outlet obstructions that result from upper gastrointestinal malignancies. Their benefits offset potential complications or malfunctions, when a pluridisciplinary approach is adopted.

Purpose Covered self-expanding metal stents (CSEMS) have been used for palliation of malignant distal biliary strictures. Occlusion of the cystic duct by CSEMS may be complicated by cholecystitis. This potentially could be prevented by placement of a transpapillary gallbladder stent (GBS). Patients and Methods Between 11/2006 and 10/2007, a total of 73 patients (50 male) aged 65 ± 14 years underwent CSEMS placement for palliation of malignant obstructive jaundice. In cases where CSEMS placement caused occlusion of the cystic duct, a 7 French transpapillary pigtail gallbladder stent (GBS) was inserted to prevent cholecystitis. Results Of the 73 patients, 18 had a prior cholecystectomy; 34 had the CSEMS placed below the cystic duct insertion. In 19 out of the 21 patients who had a CSEMS covering the cystic duct ostium, GBS placement was attempted, which was successful in 11 individuals (58%). An attempt to access the gallbladder was complicated by wire perforation of the cystic duct in three patients; one patient requiring emergent cholecystostomy tube placement. None of the patients who underwent successful GBS placement developed cholecystitis. One GBS dislodged and was repositioned. Cholecystitis occurred in two (20%) of the ten patients without transpapillary gallbladder decompression who had a CSEMS covering the cystic duct. Conclusions The ideal placement of a CSEMS is below the cystic duct insertion. Should the cystic duct ostium be occluded, placement of a GBS should be considered to minimize the risk of cholecystitis.

Erosive Tooth Wear: An Investigation in Knowledge and Prevalence The purposes of this study were 1) to determine the knowledge of dental practitioners on the clinical signs, etiology, and treatment of dental erosion, 2) to determine the prevalence of dental erosion in a population of subjects with Gastroesophageal Reflux Disease (GERD) as compared to a control population, and 3) to determine the association of number of acidic challenges, number of medications, age, salivary buffering capacity, initial salivary pH, and salivary flow rate to the erosive tooth wear (ETW) present. Results indicate that 1) while dental practitioners can identify the signs of dental erosion with a 36% accuracy, various etiologies and preventive treatment options are being overlooked, 2) the prevalence of erosion in a population of GERD subjects is 40% as compared to 15% in a control population, and 3) the only association seen is an increase of ETW with an increase in age.