Silicone-covered metal stents: an in vitro evaluation for biofilm formation and patency.

Self-expanding metal stents are being used more commonly to prevent biliary tract obstruction. Silicone-covered self-expanding metal stents (Wallstent, Schneider, Inc.) have been developed to prevent tumor ingrowth. Biofilm formation and occlusion material in silicone-covered self-expanding metal stents compared to standard polyethylene stents were examined in an in vitro model. Matched pairs of polyethylene and silicone-covered metal stents were perfused with infected bile for 8, 12, and 16 weeks at a rate of 0.5 cc/min at 37 degrees C. Two reservoirs fitted with silicone-covered metal stents had ampicillin/sulbactam added and were perfused for 16 weeks. The stents were then analyzed by scanning electron microscopy and light microscopy for biofilm formation and presence of occlusion material. The two ampicillin/sulbactam-treated stents showed no biofilm formation. Biofilm was seen on all of the remaining stents. There was a difference in occlusion thickness between the 8- and 16-week polyethylene stents, and no difference between the biofilm thickness at 8, 12, or 16 weeks in the silicone-covered metal stents. Silicone-covered self-expanding metal stents will likely extend patency rates in malignant obstructive jaundice by providing a larger lumen for bile flow and allowing cyclical antibiotics to prevent bacterial biofilm formation.

Helicobacter pylori-positive functional dyspepsia in elderly patients: comparison of two treatments.

The association of Helicobacter pylori and functional dyspepsia is not well defined. The role of H. pylori on dyspeptic symptoms is still controversial. The aim of this study is to confirm the efficacy of H. pylori eradication by two different commonly used treatment regimens, as well as to examine the improvement of the dyspeptic symptoms by eradicating H. pylori. H. pylori functional dyspepsia is prevalent in people over 60 years old. In this age group we treated 126 patients with bismuth plus metronidazole and amoxicillin (group A, 67 patients) versus omeprazole plus amoxicillin (group B, 59 patients). Results were statistically analyzed utilizing the Wilcoxon signed-rank test, McNemer test and chi-square test; P < 0.05 was considered significant. Two months after the end of therapy we observed an eradication rate of 66.1% in group A vs 64.3% in group B. All treated patients showed improvement in symptomatology. Although there was no significant difference between patients in whom H. pylori was or was not eradicated within the respective groups, when examining all H. pylori-positive patients versus H. pylori-negative posttreatment patients, there was a significant reduction (P < 0.05) in all four symptoms of functional dyspepsia measured. In conclusion, we suggest that patients treated with H. pylori-eradicating therapeutic regimens have an improvement in functional dyspepsia symptoms. We shall prefer the dual therapy as compared to the triple therapy. We believe that eradicating treatment to eradicate H. pylori in the elderly patients with H. pylori-related functional dyspepsia will reduce health care costs by reducing the number of subsequent visits.

Therapeutic ERCP: a cost-prohibitive procedure?

BACKGROUND: ERCP is increasingly being performed for therapeutic purposes and engenders a proliferation of disposable equipment without a clear indication of cost-effectiveness. METHODS: We analyzed the financial impact of ERCP by prospectively analyzing ERCPs performed in our institution from June 1, 1994, to September 30, 1994, by calculating charges related to indirect costs, disposable equipment costs, and overall reimbursement. The data were analyzed according to insurance payor as well. RESULTS: Disposable equipment costs a mean of $149 per diagnostic ERCP and $532 per therapeutic ERCP. For diagnostic ERCP, disposable equipment accounted for 27% of reimbursement; for therapeutic ERCP, disposable equipment accounted for 68% of reimbursement. Although overall reimbursement was higher for therapeutic ERCP, the very high direct costs related to disposable equipment limited the ability of reimbursement to cover indirect costs. CONCLUSIONS: Depending on the complexity of cases, quantity of disposable equipment used, and patient-insurance mix, therapeutic ERCP may be cost prohibitive for a given endoscopy unit. Indirect costs should be more carefully and quantitatively analyzed. Disposable equipment should be evaluated in terms of cost, safety, and patient outcome.

Effect of temperature on stability of eight components of porcine gallbladder bile.

Our aim was to evaluate the stability of eight components of porcine bile (pH, total and ionized calcium, total and unconjugated bilirubin, phospholipid, cholesterol, and bile salts) over a 17-day period at three temperatures: -15, 4, and 37 degrees C. The pH and concentrations of total and ionized calcium, phospholipid, cholesterol, and bile salts were stable over 17 days. Total bilirubin was stable at -15 degrees C, but declined over 17 days by approximately 25% at 4 degrees C and 70% at 37 degrees C (P < 0.003). A rapid increase in the unconjugated bilirubin was seen within two days at all temperatures to between 7.5 and 12 times the levels at day 0 (P < 0.009). Thereafter unconjugated bilirubin at -15 and 4 degrees C continued to increase at a much slower rate. By contrast, unconjugated bilirubin at 37 degrees C declined beginning on day 4 and fell to 1.33 times levels at day 0 by day 17 (P < 0.002). We conclude that bile can be stored at -15 degrees C for 17 days with stability of most components, but unconjugated bilirubin will rise. The loss in total bilirubin is significant at 37 degrees C.

Inhibition of biliary endoprostheses occlusion by ampicillin-sulbactam in an in vitro model.

An important first step in stent occlusion is the formation of a bacterial biofilm. This is followed by deposition of granules similar to that found in brown pigment stones. Previous in vitro models for studying occlusion have used synthetic biles without bilirubin or pooled human bile, which is limited in supply. Our aim was to develop a new in vitro model of stent occlusion with porcine gallbladder bile and then, with the model, assess whether ampicillin-sulbactam can prevent biofilm formation and thus occlusion. Sterile porcine gallbladder bile was contaminated with Escherichia coli then divided into eight reservoirs, four of which then received ampicillin-sulbactam. The bile was then circulated through 10F polyethylene stents. Bile was changed weekly for 8 weeks. In the stents that were untreated, biofilm and sludge were seen in all four, whereas the four ampicillin-sulbactam-treated stents had no biofilm when viewed by electron microscopy. Furthermore, the levels of calcium, cholesterol, and bilirubin in the reservoirs decreased significantly in the untreated bile as compared with the treated bile (p < 0.05). In this in vitro model, the losses of calcium, cholesterol, and bilirubin are likely caused by deposition of granules into the biofilm matrix. Ampicillin-sulbactam can prevent biofilm formation if used continuously.