The popcorn Wolbachia infection of Drosophila melanogaster: can selection alter Wolbachia longevity effects?

Wolbachia popcorn (wMelPop), a life-shortening strain of Wolbachia, has been proposed as an agent for suppressing transmission of dengue fever following infection of the vectoring mosquito Aedes aegypti. However, evolutionary changes in the host and Wolbachia genomes might attenuate any life span effects mediated by wMelPop. Here we test for attenuation by selecting strains of Drosophila melanogaster infected with wMelPop for early and late reproduction in three independent outcrossed populations. Selection caused divergence among the lines in longevity. This divergence was mostly associated with the host genetic background rather than the Wolbachia infection, although there were also interactions between the host and Wolbachia genomes. Development time, viability, and productivity were not altered by selection. The implications of these results are discussed in light of the intended use of wMelPop for suppressing disease transmission.

Molecular analysis to detect pancreatic ductal adenocarcinoma in high-risk groups.

BACKGROUND & AIMS: Screening of high-risk groups for pancreatic cancer has not been adopted because of concerns regarding specificity and sensitivity. Suitability of a combination of 3 novel molecular screening techniques was investigated. METHODS: Pancreatic juice was extracted from 146 patients with pancreatic ductal adenocarcinoma, chronic pancreatitis, or biliary tract stones. p53 mutations were analyzed by using a modified yeast functional assay, K-ras status was analyzed using mutation-specific real-time PCR and the proportion of p16(INK4a) promoter methylation was estimated using comparative methylation-specific real-time PCR. RESULTS: p53 mutations were detected in 20 of 48 (42%) cancer cases, none of 49 controls, and 2 of 49 (4%) patients with pancreatitis. K-ras mutations were detected in 31 of 57 (54%) cancer patients, 13 of 61 (21%) controls, and 23 of 67 (34%) patients with pancreatitis. Twenty-six of 42 (62%) cancer patients had promoter methylation levels > 12%, compared with 3 of 24 (13%) controls, and 2 of 26 (8%) with pancreatitis. Mutations in p53 or high-level p16(INK4a) promoter methylation occurred in 29 of 36 (80%) patients with cancer, 3 of 24 (13%) controls, and 3 of 22 (13%) with pancreatitis. Three patients (8%) of 36 with cancer; 14 of 24 (58%) controls, and 13 of 22 (59%) patients with pancreatitis had no marker. The gallstone disease patients had a high rate of positive K-ras mutations, possibly reflecting the fact that they were not disease free. CONCLUSIONS: Combination molecular analysis increased the discrimination between patients with malignant and benign disease. This level of discrimination would allow patients in high-risk groups to be stratified from negligible risk to over 50% probability of an early cancer.

Isolated Roux-loop pancreaticojejunostomy: a series of 61 patients with zero postoperative pancreaticoenteric leaks.

There have been approximately 70 reported variations of reconstruction after pancreaticoduodenectomy (PD). The pancreaticojejunal (PJ) anastomosis is the source of most reported morbidity and mortality. In this study, we aimed to identify the anastomotic leak rate in patients undergoing PD for malignant disease using a proximal isolated jejunal pancreatic anastomosis. Sixty-one consecutive patients undergoing PD (26 women and 35 men; age range, 41-79 years, mean age, 62 years). had an identical reconstruction. The PJ anastomosis was performed using the most proximal isolated jejunum in two layers: interrupted 4.0 Prolene was used to achieve mucosal/ductal continuity, and 3.0 Prolene was used for the serosal/parenchymal anastomosis, around an appropriately sized stent. All postoperative complications were recorded. A pancreatic leak was defined as persistent discharge of amylase-rich pancreatic drain fluid. The overall complication rate was 44% (27 of 61, including 15 chest infections, 8 wound infections, and 2 postoperative cardiac arrhythmias). There were 3 deaths (30-day mortality rate, 5%). One patient died after a cerebrovascular accident, one from respiratory failure secondary to pneumonia, and the third of methicillin-resistant Staphylococcus aureus septicemia after small bowel ischemia caused by pressure necrosis from a drain. There were no PJ anastomotic leaks. This method of pancreatojejunostomy has produced a 0% leak rate in this center.