Fraction of informative recombinations: a heuristic approach to analyze recombination rates.

In this article we present a new heuristic approach (informative recombinations, InfRec) to analyze recombination density at the sequence level. InfRec is intuitive and easy and combines previously developed methods that (i) resolve genotypes into haplotypes, (ii) estimate the minimum number of recombinations, and (iii) evaluate the fraction of informative recombinations. We tested this approach in its sliding-window version on 117 genes from the SeattleSNPs program, resequenced in 24 African-Americans (AAs) and 23 European-Americans (EAs). We obtained population recombination rate estimates (rho(obs)) of 0.85 and 0.37 kb(-1) in AAs and EAs, respectively. Coalescence simulations indicated that these values account for both the recombinations and the gene conversions in the history of the sample. The intensity of rho(obs) varied considerably along the sequence, revealing the presence of recombination hotspots. Overall, we observed approximately 80% of recombinations in one-third and approximately 50% in only 10% of the sequence. InfRec performance, tested on published simulated and additional experimental data sets, was similar to that of other hotspot detection methods. Fast, intuitive, and visual, InfRec is not constrained by sample size limitations. It facilitates understanding data and provides a simple and flexible tool to analyze recombination intensity along the sequence.

Detection of methicillin/oxacillin resistance and typing in aminoglycoside-susceptible methicillin-resistant and kanamycin-tobramycin-resistant methicillin-susceptible Staphylococcus aureus.

Eighty-five atypical isolates of Staphylococcus aureus divided into 73 aminoglycoside-susceptible methicillinresistant (AS-MRSA) and 12 kanamycin-tobramycin-resistant methicillin-susceptible (KTR-MSSA) were phenotypically and genotypically examined for methicillin resistance. Among these tests, the diffusion method using the oxacillin and cefoxitin disks on Mueller-Hinton agar with and without NaCl, the incubation at 35 degrees C or 30 degrees C for 24 or 48 hr, respectively, and the determination of oxacillin MICs by E-test were performed. We also examined the presence of the mecA gene by PCR and its product PBP 2a by the Slidex MRSA Detection test after induction by cefoxitin disk. All of the AS-MRSA strains (100%) were detected by the cefoxitin disk in all conditions and by the oxacillin disk on Mueller-Hinton agar with 2% of NaCl at 35 degrees C. Without NaCl, the sensitivity fell to 97.2% by oxacillin disk. The oxacillin MICs for these isolates ranged from 2 to 128 mg/L. The mecA gene determinant and its product PBP 2a were detected in all AS-MRSA strains. All KTR-MSSA strains were phenotypically methicillin-susceptible and oxacillin MICs were below or borderline of breakpoint (< or =2 mg/L). The mecA gene determinant and its product were detected in one strain. Pulsed-field gel electrophoresis (PFGE) was applied and revealed the presence of two major patterns A (36.9%) and B (46.2%) in AS-MRSA isolates and seven patterns in the KTR-MSSA strains.

[Image guided drainage of pelvic fluid collections: results in 42 patients]. / Drainage radiologique des collections pelviennes: résultats chez 42 malades.

PURPOSE: To review the etiology, location, and morphology of pelvic collection as well as the technique and results of image guided drainage. MATERIALS AND METHODS: From June 1996 to August 2002, we performed image guided drainage of pelvic fluid collections in 21 males and 21 females. In patients where a direct contact between the collection and the endocavitary probe was present, the drainage was performed either by transrectal or transvaginal approach using 10F, 12F, 14F or 16F catheters according to the viscosity of the fluid. When the patients were no longer septic, when drainage had stopped, the drains were removed at day 5. When a fistula was present, the drain was left in place until the fistula healed. RESULTS: The most common location of pelvic collections was the cul-desac (43%). A total of 81% of pelvic abscesses were digestive in origin, either from the colon or appendix. Transrectal or transvaginal drainage was possible in 83% of cases. Mean follow-up was 41 months. No drainage related complication was recorded. In two patients with collections of clear fluid, a simple aspiration was performed without insertion of a drain. In the 40 other patients, a drainage catheter was inserted. Twenty-nine patients were cured after 15 days of drainage. Two patients had recurrent collections. Image guided drainage failed in five patients, and all underwent successful surgical management. CONCLUSION: Image guided drainage of pelvic collections is a safe and effective procedure. Failures were due to initially undiagnosed pathology requiring surgical treatment.

Detection and validation of single gene inversions.

MOTIVATION: The biologically meaningful algorithmic study of genome rearrangement should take into account the distribution of sizes of the rearranged genomic fragments. In particular, it is important to know the prevalence of short inversions in order to understand the patterns of gene order disruption observed in comparative genomics. RESULTS: We find a large excess of short inversions, especially those involving a single gene, in comparison with a random inversion model. This is demonstrated through comparison of four pairs of bacterial genomes, using a specially-designed implementation of the Hannenhalli-Pevzner theory, and validated through experimentation on pairs of random genomes matched to the real pairs.

[Percutaneous treatment of intrahepatic lithiasis]. / Traitement percutané de la lithiase intra-hépatique.

AIM: To present our experience with percutaneous intracorporeal electrohydrolic lithotripsy in the treatment of intrahepatic lithiasis. SUBJECTS AND METHODS: From January 1989 to November 1998, 53 patients with intrahepatic lithiasis were treated with percutaneous intracorporeal electrohydrolic lithotripsy. Twenty-six patients had primary intrahepatic lithiasis. Intrahepatic stones were associated with intrahepatic duct abnormalities in 11 patients, 9 had strictures and 2 had cystic dilatations. Twenty-seven patients had secondary intrahepatic lithiasis formed a biliodigestive bypass in 20 patients. Intracorporeal electrohydrolic lithotripsy was performed under cholangioscopic guidance in all patients. The endoscope was introduced into the biliary ducts through a cutaneobiliary tract in 51 patients, through a cutaneocholecystic tract in one and through a cutaneojejunal tract in one. These tracts were created and gradually dilated in two sessions three days apart. In twenty-two patients stenosis or sharp angulation prevented adequate positioning of the scope which was only successful after balloon dilation or insertion of a stiff wire. RESULTS: Complete clearance of stones was achieved in 49 patients (92%). Biliary or hepaticojejunostomy strictures were successfully dilated with an angioplasty balloon in all patients. Ten patients (19%) had early complications: four had bilomas treated by percutaneous drainage, three had resolutive onset of cholangitis, two had transient arterial hemobilia, and one had a pneumothorax. The mean duration of follow-up was five years. During this period, 5 patients (9%) had recurrent symptoms of biliary obstruction. Among these patients, three (5.7%) had recurrent symptomatic intrahepatic lithiasis, one had a recurrent biliary stricture and one had secondary sclerosing cholangitis. Treatment of recurrent stones was repeated intracorporeal electrohydrolic lithotripsy in two and left hepatectomy in one; recurrent biliary stricture was treated by hepaticojejunostomy and secondary sclerosing cholangitis by antibiotics. CONCLUSION: Intracorporeal electrohydrolic lithotripsy is effective and safe and should be proposed as the first line treatment of primary or secondary intrahepatic lithiasis.

Epidemiological study of an Acinetobacter baumannii outbreak by using a combination of antibiotyping and ribotyping.

From June to November 1994 (period 1) and from February to June 1995 (period 2), multiresistant Acinetobacter baumannii strains were isolated in intensive care units and surgical wards of the Amiens Teaching Hospital Center (Amiens, France). Eighteen isolates were obtained from 17 (1%) of 1,706 patients admitted during both of these periods, giving an incidence rate of nosocomial infection per 1,000 patient days of 0.6%. Of 17 infected patients, 9 had pneumonia, 3 had urinary tract infection, 2 had peritonitis, 1 had septicemia, 1 had a catheter infection, and 1 had pneumonia and urinary tract infection. According to typing results, four antibiotic resistance profiles were detected: a, b, c, and d; seven ribotypes were distinguished by both restriction enzymes EcoRI and SalI (A, B, C, D, E, F, and G). By combining antibiotyping and ribotyping, we obtained eight groups of strains (groups I to VIII). Group I contained five strains (strains 4, 5, 7, 8, and 9) which had antibiogram pattern a and ribopattern A and constituted the outbreak strains. The strains of group II (strains 3, 10, 11, 13, and 14) were closely related to outbreak strain A and appeared to be variants of ribotype A (A2 [strain 3]; A4 [strain 10]; A5 [strains 11, 13, and 14]). Groups III, IV, V, VI, VII, and VIII included strains which were epidemiologically unrelated to the strains of group I and were considered nonoutbreak strains.

Placement of metallic stents for treatment of postoperative biliary strictures: long-term outcome in 25 patients.

OBJECTIVE: This study was undertaken to evaluate the results of our 7-year experience with Gianturco-Rosch metallic stents, used for the management of postoperative biliary strictures. SUBJECTS AND METHODS: From January 1989 to April 1995, self-expanding Gianturco-Rosch metallic stents were placed in 25 patients with postoperative bile duct stenosis. All patients had a history of bile duct injury during cholecystectomy. Twenty-four patients had a conventional open cholecystectomy and one patient had a laparoscopic cholecystectomy. Eight patients had stenosis at the level of the common bile duct. The other 17 patients, who had undergone surgical repair of the bile duct, had a stricture at the level of the hepaticojejunostomy. These anastomotic strictures recurred after simple cholangioplasty. Patients were monitored for 9-84 months (mean, 55 months). Treatment was considered successful if the initial stenosis did not recur. Treatment was considered a failure if the initial stenosis recurred within the stent. RESULTS: Two patients had early complications: one had bile pleural effusion, treated with percutaneous drainage, and the other had arterial hemobilia, treated with embolization. Eighteen (72%) of 25 patients had no recurrence of the initial strictures. Among these patients, 11 had no further symptoms of biliary obstruction and seven, all with strictured hepaticojejunostomies, had recurrent episodes of cholangitis caused by secondary sclerosing cholangitis or intrahepatic stone formation. Seven (28%) of 25 patients had recurrence of the initial stenoses, causing repeated episodes of cholangitis. Among these seven patients, six had common bile duct stenoses and one had an anastomotic stricture. Recurrent biliary obstruction was treated surgically or with percutaneous methods, despite the presence of the metallic stent. CONCLUSION: Gianturco-Rosch stent placement should be considered in patients with postoperative bile duct stenoses in whom another operation is not indicated and cholangioplasty has failed. The results are better in patients who have hepaticojejunostomy strictures rather than common bile duct strictures. Overall, a long-term recurrence rate of cholangitis of more than 50% of patients was seen because of recurrence of the original stenosis or intrahepatic bile duct obstruction.

Genotyping of Portuguese Chlamydia trachomatis urogenital isolates.

OBJECTIVE: To determine the prevalence of the different Chlamydia trachomatis genotypes in Portuguese patients. METHODS: Urogenital isolates (n = 240) derived from attenders of various clinics in the Lisbon area were differentiated into genovars by genotyping with restriction fragment length polymorphism (RFLP) analysis of the PCR amplified omp1 gene. RESULTS: Genotype E was the most common for both men (47.9%) and women (43.8%). Genotypes D and F were the second most prevalent for men (11.3%) and genotype H was the second most prevalent for women (19.5%). Genotypes F, G, D, in women and H, G, I, in men, were found in a lower percentage of cases. Genotypes B, Ba, J, K, L1 and L2 were very rarely detected. CONCLUSIONS: With one exception, the overall distribution of Chlamydia trachomatis genotypes in our study is similar to what has been observed in other western countries. The only exception is the unusual prevalence of genotype H among women. The clinical manifestations associated with this and other genotypes were similar.

Limits of the microimmunofluorescence test and advantages of immunoblotting in the diagnosis of chlamydiosis.

The Western blot (immunoblot) patterns of 56 serum specimens, all examined previously by the microimmunofluorescence (MIF) test for species-specific Chlamydia antibodies, were analyzed. Predominant specific-antibody activity was directed to the 170-, 155-, 145-, 120-, 115-, 100-, 57-, and 38-kDa proteins of Chlamydia trachomatis and to the 175-, 130-, 110-, 98-, and 30-kDa proteins of Chlamydia pneumoniae. All of these antigens appeared to be species specific. The reactivity with 90-, 80-, 75-, 62- or 60-, and 55-kDa proteins and the major outer membrane protein appeared to be genus specific. Fourteen serum samples which had identical titers of immunoglobulin G as determined by the MIF test were investigated by Western blotting. We found that nine serum samples had anti-C. trachomatis protein profiles and two had anti-C. pneumoniae protein profiles. The double seropositivity observed by MIF corresponded with cross-reactivity to genus-specific antibodies. As for the three remaining serum specimens, we observed identical protein profiles for C. trachomatis and C. pneumoniae, confirming the double seropositivity experienced with the MIF test. Western blotting can differentiate between specific reactions and interfering noise from other, partly cross-reacting chlamydial species.

Percutaneous transrenal electro-incision of ureterointestinal anastomotic strictures: long-term results and comparison of fluoroscopic and endoscopic guidance.

PURPOSE: We determined the long-term outcome of a new technique for incising ureterointestinal anastomotic strictures using a transrenal percutaneously inserted papillotome. Procedures using fluoroscopic and endoscopic guidance were compared. MATERIALS AND METHODS: Of 33 stenoses incised in 30 patients 15 were in ileal conduit diversions and 15 were in enterocystoplasties. The papillotome was inserted percutaneously over a guide wire into the stenosis, and then deflected and gently withdrawn under fluoroscopic (11 cases) or endoscopic (22) guidance using a flexible pediatric gastroscope or a lateral duodenoscope inserted retrograde into the ileal loop or neobladder. Air filling provided an excellent view of the stenotic area. Operative time did not exceed 45 minutes. The only major complication was damage to a right internal iliac artery. RESULTS: Followup data were available for 31 stenoses, with 27 followed for longer than 12 months after stent removal. Of the stenoses 22 are completely patent (actuarial long-term patency rate 71%), 3 showed partial improvement and 6 recurred requiring further treatment. CONCLUSIONS: Combined endoscopic and fluoroscopic guidance is preferable to fluoroscopy alone. The technique is simple if the endoscope is inserted retrograde. Long-term results are satisfactory and we believe that incision should be the initial approach to strictures of uro-digestive anastomoses.

[Percutaneous treatment of malignant stenoses of the hilum]. / Traitement percutané des sténoses malignes du hile.

PURPOSE: The endoscopic treatment of malignant hilar obstruction is followed in 70% of the case by infection of undrained biliary sectors. We report the influence of complete biliary drainage on post procedural cholangitis. METHOD: From January 1990 to January 1993 we treated 120 consecutive patients presenting with a malignant hilar obstruction. There were 61 women and 59 men, mean age 65 +/- 7.5 years. The level of stenosis was type II in 45 patients (37%), type III in 18 patients (13%) and above type III in 57 patients (48%). Complete biliary drainage with multiple biliary access was attempted in all patients. Long term internal drainage was achieved by metallic autoexpansive endoprosthesis. RESULTS: Complete drainage was achieved in all patients with type II or type III biliary stenosis. Drainage was incomplete in all patients with biliary stenosis above type III. Early complications were observed in 35% of the patients. Persistent cholangitis, the most frequent complication (22%) was only observed in patients with above type III biliary stenosis. Mortality at 30 days was 17%. Recurrent biliary obstruction was observed in 22% of the patients after an average of 187 days. Median survival was 95 days. CONCLUSION: Complete biliary drainage prevents persistent cholangitis in patients with type II or III biliary stenosis without increasing other complications related to biliary drainage.

Retrograde pancreatography. Technical tips and spectrum of pathology.

ERP is an important technique in the diagnosis of diseases involving the pancreatic ducts, in determining therapeutic strategy, and in assessing the results of surgical bypass procedures. ERP facilitates the diagnosis of the majority of pancreatic tumors at a stage when they normally present to the clinician. It assists the diagnosis of small tumors in the ampullary region at an early stage when other tests are negative. In cases of obscure recurrent pancreatitis, ERP may identify a mechanical cause (e.g., stone, stricture). ERP is useful in the diagnosis of CCP only in the precalcified stage. If histologic confirmation already has been obtained at surgery, ERCP is not required. Compared with noninvasive techniques, ERP provides additional information: It enables a concomitant examination of the gastroduodenal tract and opacification of the bile ducts; additional procedures may be performed, such as intraductal cytologic brushings, biochemical and cytologic analysis of pancreatic juice, endoscopic manometry, and pancreatoscopy. The diagnostic yield is increased if these procedures are performed during ERCP. Because ERP outlines the ductal anatomy, it is of great value in assessing therapeutic strategy. In cases of acute recurrent pancreatitis or chronic pancreatitis, ERP provides an important baseline for performing procedures such as ductal drainage and therefore reduces the inappropriate use of exploratory laparotomy. In cases of necrotic pancreatitis or pancreatic trauma, ERP enables accurate localization of a pancreatic fistula and facilitates any subsequent surgical procedure. Finally, ERP is the method of choice when assessing the patency of pancreatic-digestive anastomosis.

Management of clinically relevant bleeding following endoscopic sphincterotomy.

We report here on our experience of clinically relevant bleeding after endoscopic sphincterotomy (ES). Relevant bleeding was defined by the occurrence of (a) hematemesis or melena and (b) at least a two-point drop in hemoglobin, with no other bleeding source on endoscopy. These two criteria were met in 16 patients between 1983 and 1992. They represented 0.65% of all ES procedures performed during this period. Bleeding occurred immediately after ES in five cases, and was delayed in 11 cases from one to eight days (mean two days). Patients were retrospectively classified into three groups according to the severity of bleeding and subsequent clinical management. In six cases (group 1), bleeding developed slowly without shock and stopped spontaneously. In five cases (group 2), bleeding developed rapidly with melena and a drop in hemoglobin, but without shock. These patients were successfully managed with sclerotherapy without any further complications. The five patients in Group 3 had brisk bleeding with hematemesis and shock. Endoscopic hemostasis could not be performed; emergency arteriography disclosed active bleeding in four patients, and embolization of the gastroduodenal artery was performed. Bleeding stopped in all patients. Billroth II anastomosis appeared to be the only factor associated with an increased risk of clinically relevant bleeding. It was possible to control bleeding following ES using endoscopic or angiographic hemostasis, surgery being avoided in all cases.

[The prevalence of anti-Chlamydia trachomatis and anti-Chlamydia pneumoniae antibodies in Brazzaville]. / Prévalence des anticorps anti-Chlamydia trachomatis et anti-Chlamydia pneumoniae à Brazzaville.

The prevalence study of antibodies to Chlamydia trachomatis and Chlamydia pneumoniae in Brazzaville were screened from 108 women (56 pregnant women, 18 infertile women and 34 women affected with genital tract infections) and 108 blood donors (control subjects) by indirect microimmunofluorescent assay. 57.4% of studied women were carrying Chlamydia trachomatis antibodies, and 51.8% had C. pneumoniae antibodies. Prevalence of Chlamydia antibodies by women group studied was estimated to be: in pregnancy women group 51.7% of C. trachomatis antibodies and 62.5% of C. pneumoniae antibodies; in infertile women group 61.1% of C. trachomatis antibodies and 33.3% of C. pneumoniae antibodies; in women affected with genital tract infections group: 64.7% of C. trachomatis antibodies and 44.1% of C. pneumoniae antibodies. In blood donors group, the prevalence of IgG antibodies against Chlamydia trachomatis is 27.7% and 37% for IgG antibodies against C. pneumoniae.

[Large calculi of the common bile duct. Value of lithotripsy]. / Calculs volumineux de la voie biliaire principale. Intérêt de la lithotritie.

Certain stones need to be fragmented before being extracted via endoscopic sphincterotomy (ES). From April 1988 to December 1991, extracorporeal lithotripsy was used in this indication in 28 patients (22 females, 6 males) with a mean age of 77 +/- 20 years, using an ultrasound-guided electrohydraulic lithotriptor. Stone detection was performed after perfusion of the nasogastric tube and was easy in 20 cases (71%), difficult in 6 cases (22%) and impossible in 2 cases (7%), which could not be treated by this method. The patients had an average of 1.4 +/- 0.9 stones measuring 19.6 +/- 8 mm and received an average of 2.480 +/- 580 shock waves in a single session for 24 patients and in two sessions for 2 patients. Radiologically obvious fragmentation was achieved in 11 out of 26 cases (42%) and was found to be effective at a further extraction attempt in 4 other cases. Complete clearance of the common bile duct was achieved in 15 cases (57.7%). The size of the stones (> or < 20 mm) and the solitary or multiple nature of the stones did not significantly influence the fragmentation results. No complication related to the technique was observed apart from the constant development of cutaneous petechiae. An improvement in the power of the generator and the use of fluoroscopic rather than ultrasonographic guidance should allow an improvement of these results in the future. Because of its safety, this lithotripsy method can be proposed following failure of mechanical lithotripsy.

[Current results of endoscopic sphincterotomy for lithiasis of the common bile duct]. / Résultats actuels de la sphinctérotomie endoscopique pour lithiase de la voie biliaire principale.

Between January 1989 and June 1990, endoscopic sphincterotomy was performed in 308 consecutive patients with common bile duct stones (mean age: 74 years). Complete clearance of common bile duct was achieved at the first attempt in 65% of cases. This rate was significantly related to the size and the number of biliary stones. The success rate reached 97 percent after repeated endoscopic sessions (127 patients), mechanical lithotripsy (20 patients), extracorporeal or intracorporeal lithotripsy (18 and 11 patients, respectively). During the month following the endoscopic sphincterotomy, 39 patients (13%) developed one or more complications and 11 patients (3.7%) died. The complication rate was related to the time elapsed between biliary opacification and endoscopic sphincterotomy (P = 0.04) and between endoscopic sphincterotomy and total common bile duct clearance (P = 0.0007). No patient younger than 75 years died, but death occurred in 4.5% of the patients older than 75 years. Thirty patients (10%) developed endoscopic sphincterotomy-related complications. Cholangitis and bleeding were the most frequent complications (4 and 2%, respectively). Cholangitis occurred more frequently among the patients older than 75 (P < 0.05) or when transhepatic guided endoscopic sphincterotomy or intracorporeal lithotripsy was used (P < 0.005). Cholangitis led to death in 2 patients, 86 and 87 years old (0.7%). Endoscopic sphincterotomy related complications developed within 48 hours in all but 4 patients (2 patients with pancreatitis and 2 patients with cholecystitis).

[Endoscopic drainage of pseudocysts of the pancreas. Study of 26 cases]. / Drainage endoscopique des pseudo-kystes du pancréas. Etude de 26 cas.

Endoscopic drainage of pancreatic pseudocysts has been proposed for several years as an alternative to surgical treatment. We report the results of 26 endoscopic cystostomies of pancreatic pseudocysts (13 cystoduodenostomies, 13 cystogastrostomies) performed in two specialized centres, from 1985 to 1991. The patients were divided into 3 groups (I, II, III) according to the pseudocysts' clinical presentation. The opening of the collection into digestive lumen was achieved in 22 cases; there were 3 puncture failures and 1 cystostomy was not performed because of a prior haemorrhagic puncture. Pain relief was obtained rapidly after cystodigestive drainage in 13 out of the 14 symptomatic patients. Three complications required surgery: 1 bleeding after cystoduodenostomy, 1 perforation and 1 peritonitis after cystogastrostomies. Two of them occurred after recutting a cystostomy. Two pseudocyst surinfections healed with antibiotic therapy. No deaths occurred due to the procedure. Among the 18 long-term followed-up patients (average = 33 months), 4 required surgery for persistence or relapse of pseudocysts. The results were excellent for the 14 other patients without any difference between cystoduodenostomies and cystogastrostomies, neither between the I, II and III groups. Each of the 5 cases with a digestive lumen-pseudocyst cavity thickness above 1 cm (measured on 20 CT scans) failed: 1 puncture failure, 3 complications, 1 relapse.

[Palliative treatment by endoprosthesis of icterus caused by distal biliary tumoral obstruction]. / Traitement palliatif par endoprothèse des ictères par obstacle tumoral biliaire sous-hilaire.

Between March 1982 and December 1987, 466 patients (256 women, 210 men, mean age 73 years) with tumor obstruction of the common bile duct were referred to our department. The causes of obstruction were carcinoma of the pancreas (298 patients), carcinoma of the ampulla of Vater (32 patients) and carcinoma of the common bile duct (136 patients). Endoscopical insertion of a biliary prosthesis was initially possible in 377 patients (81%). In case of failure, patients were referred to the radiologist for percutaneous drainage. Successful drainage was obtained in 58 patients with an overall success rate of 93% (435 patients). Endoscopic replacement was necessary in 170 cases for 114 patients and was successful in 155 (91%). Pruritus was relieved in 89% of the patients. Serum bilirubin levels decreased more than 75% after initial endoscopic endoprosthesis, repeated endoscopic endoprosthesis and percutaneous prosthesis insertion in 80%, 79%, and 62% of the patients, respectively. Short term complications of endoscopic endoprosthesis occurred in 28% of patients with a mortality rate of 8%. Percutaneous prosthesis complications occurred in 33% of patients with a mortality rate of 11%. In the long term, cholangitis was the main complication and occurred in 27% of patients with a delay of 103 +/- 105 days. Intestinal obstruction was observed in 7% of patients. The average life expectancy of endoscopic endoprosthesis and percutaneous prosthesis was 109 +/- 157 and 92 +/- 101 days, respectively. The average life expectancy of patients was 163 +/- 224 days.(ABSTRACT TRUNCATED AT 250 WORDS)

Biliary stent occlusion--a problem solved with self-expanding metal stents? European Wallstent Study Group.

The main limitation in the endoscopic palliation of malignant biliary obstruction is due to stent blockage. One of the factors thought to be of importance is the diameter of the endoprosthesis. In this paper, we report the results of a multicenter European study with a one cm diameter self-expanding metal stent (Wallstent) in 103 patients with malignant biliary obstruction. Insertion of the stent following guidewire positioning was successful in 97.1% of the patients without any cases of de novo cholangitis developing after the endoscopic procedure. The median follow-up for the entire group was 145 days. In all but 3 patients, the stent expanded to more than 80% of its maximum diameter. Two patients had ongoing cholangitis after stent insertion. Long-term complications manifested by late cholangitis, were seen in 18% of the cases after a median interval of 125 days. The occlusion rate by biliary sludge was 5% after a median time period of 175 days which is substantially less than the 21% occlusion rate reported for polyethylene stents. In conclusion, our results show that the Wallstent can be easily placed in distal and mid-CBD strictures after guidewire passage, with most of the patients having a- good drainage effect. The occlusion rate by biliary sludge is significantly less than for conventional polyethylene stents, but the occlusion by tumor ingrowth is substantial. A disadvantage is the high cost of the Wallstent. Further randomized trials will be required to determine the cost-benefit ratio for the use of this stent.