Comparative transcriptomics of mountain pine beetle pheromone-biosynthetic tissues and functional analysis of CYP6DE3.

BACKGROUND: The mountain pine beetle (MPB, Dendroctonus ponderosae Hopkins) is a highly destructive pest of pine forests in western North America. During flight to a new host tree and initiation of feeding, mountain pine beetles release aggregation pheromones. The biosynthetic pathways of these pheromones are sex-specific and localized in the midgut and fat body, but the enzymes involved have not all been identified or characterized. RESULTS: We used a comparative RNA-Seq analysis between fed and unfed male and female MPB midguts and fat bodies to identify candidate genes involved in pheromone biosynthesis. The 13,407 potentially unique transcripts showed clear separation based on feeding state and gender. Gene co-expression network construction and examination using petal identified gene groups that were tightly connected. This, as well as other co-expression and gene ontology analyses, identified all four known pheromone biosynthetic genes, confirmed the tentative identification of four others from a previous study, and suggested nine novel candidates. One cytochrome P450 monooxygenase, CYP6DE3, identified as a possible exo-brevicomin-biosynthetic enzyme in this study, was functionally characterized and likely is involved in resin detoxification rather than pheromone biosynthesis. CONCLUSIONS: Our analysis supported previously characterized pheromone-biosynthetic genes involved in exo-brevicomin and frontalin biosynthesis and identified a number of candidate cytochrome P450 monooxygenases and a putative cyclase for further studies. Functional analyses of CYP6DE3 suggest its role in resin detoxification and underscore the limitation of using high-throughput data to tentatively identify candidate genes. Further functional analyses of candidate genes found in this study should lead to the full characterization of MPB pheromone biosynthetic pathways and the identification of molecular targets for possible pest management strategies.

Development of a virtual reality haptic Veress needle insertion simulator for surgical skills training.

The Veress needle is the most commonly used technique for creating the pneumoperitoneum at the start of a laparoscopic surgical procedure. Inserting the Veress needle correctly is crucial since errors can cause significant harm to patients. Unfortunately, this technique can be difficult to teach since surgeons rely heavily on tactile feedback while advancing the needle through the various layers of the abdominal wall. This critical step in laparoscopy, therefore, can be challenging for novice trainees to learn without adequate opportunities to practice in a safe environment with no risk of injury to patients. To address this issue, we have successfully developed a prototype of a virtual reality haptic needle insertion simulator using the tactile feedback of 22 surgeons to set realistic haptic parameters. A survey of these surgeons concluded that our device appeared and felt realistic, and could potentially be a useful tool for teaching the proper technique of Veress needle insertion.

Persistent pancreatocutaneous fistula after percutaneous drainage of pancreatic fluid collections: role of cause and severity of pancreatitis.

PURPOSE: To assess the relationship between the cause and severity of pancreatitis and the development of persistent pancreatocutaneous fistula (PPCF) after percutaneous drainage of pancreatic fluid collections. MATERIALS AND METHODS: Sixty patients (44 male, 16 female; age range, 10-74 years) were included in the study. The cause of pancreatitis was postoperative in 29 patients, alcoholism in 20 patients, biliary in six patients, hyperlipidemia in two patients, unknown in two patients, and trauma in one patient. Patients requiring intensive care unit treatment for their condition at the time of drainage were considered to have severe pancreatitis. Thirty-seven patients had mild pancreatitis, and 23 had severe pancreatitis. PPCF was defined as catheter drainage of pancreatic fluid of more than 10 mL/d for more than 4 weeks after catheter placement. RESULTS: PPCF developed in 27 of the 60 patients. It occurred in five of the six patients with biliary pancreatitis, 10 of the 20 with alcohol-related pancreatitis, and 10 of the 29 with postoperative pancreatitis (P > .2). The prevalence of PPCF was higher in patients with severe pancreatitis (n = 16 [70%]) than in those with mild pancreatitis (n = 11 [30%]). This difference was statistically significant (P < .002). CONCLUSION: Development of PPCF correlated with severity of pancreatitis, regardless of the cause of pancreatitis.