Staging laparoscopy in pancreatic cancer: a potential role for advanced laparoscopic techniques.

BACKGROUND: The role of staging laparoscopy in pancreatic cancer in the age of high-resolution CT scans is under debate. This study's aim is to evaluate the efficacy of staging laparoscopy in this disease. STUDY DESIGN: A retrospective cohort study was conducted evaluating patients who underwent operative treatment for radiographic stage I to III pancreatic cancer between July 2003 and October 2012. Radiographic follow-up was 94% at 6 months. RESULTS: Of 274 patients who met inclusion criteria, 136 underwent staging laparoscopy, which identified radiographic occult distant metastases in 2% (3 of 136). However, subsequent laparotomy identified an additional 9% (12 of 136) harboring distant metastases in regions not visualized on standard staging laparoscopy; specifically, the posterior liver surface, paraduodenal retroperitoneum, proximal jejunal mesentery, and lesser sac. The remaining 138 patients underwent initial staging laparotomy, which showed similar results identifying radiographic occult distant disease in 11% (15 of 138). Within 6 months after the operation, peritoneal or subcapsular liver metastases developed in an additional 6% (15 of 257)-disease that potentially could have been diagnosed at the time of operation-providing a false-negative rate of 88% for staging laparoscopy compared with 36% for staging laparotomy. CONCLUSIONS: Despite the availability of high-resolution CT scans, occult distant metastases can still be found in 11% of patients during the operation. In the absence of reliable risk factors to predict distant metastases, staging laparoscopy should be offered to all patients with radiographic localized disease. However, the results favor extended laparoscopic staging with evaluation of the posterior liver surface, mobilization of the duodenum, evaluation of the proximal jejunal mesentery, and visualization of the lesser sac.

HTRF-based assay for microsomal prostaglandin E2 synthase-1 activity.

Microsomal prostaglandin E2 synthase-1 (mPGES-1) catalyzes the formation of prostaglandin E2 (PGE2) from the endoperoxide prostaglandin H2 (PGH2). Expression of this enzyme is induced during the inflammatory response, and mouse knockout experiments suggest it may be an attractive target for antiarthritic therapies. Assaying the activity of this enzyme in vitro is challenging because of the unstable nature of the PGH2 substrate. Here, the authors present an mPGES-1 activity assay suitable for characterization of enzyme preparations and for determining the potency of inhibitor compounds. This plate-based competition assay uses homogenous time-resolved fluorescence to measure PGE2 produced by the enzyme. The assay is insensitive to DMSO concentration up to 10% and does not require extensive washes after the initial enzyme reaction is concluded, making it a simple and convenient way to assess mPGES-1 inhibition.

Homogeneous time-resolved fluorescence and its applications for kinase assays in drug discovery.

The rapidly growing interest in kinases as potential targets for therapeutic intervention has prompted the development of many kinase assay technologies. One exciting example is homogeneous time-resolved fluorescence (HTRF). An HTRF assay utilizes the signal generated by the fluorescence resonance energy transfer between donor and acceptor molecules in close proximity. Dual-wavelength detection helps to eliminate media interference, and the final signal is proportional to the extent of product formation. Thus far, the reported applications of this technology for in vitro kinase assays have mainly focused on high-throughput screening. In this report, we extend the applications of HTRF technology to the areas of enzyme and inhibitor characterization, some aspects of which were previously believed impossible. We describe the methods developed for determining the kinetic parameters of an enzyme, such as K(m) and k(cat), and the procedures for inhibitor mechanistic studies including ATP competitiveness and slow-binding and dissociation kinetics. These assays can be readily applied to any kinase and are valuable in advancing a program through the early stages of drug discovery.