Mitochondria in epithelial ovarian carcinoma exhibit abnormal phenotypes and blunted associations with biobehavioral factors.

Malignant tumor cells exhibit mitochondrial alterations and are also influenced by biobehavioral processes, but the intersection of biobehavioral factors and mitochondria in malignant tumors remains unexplored. Here we examined multiple biochemical and molecular markers of mitochondrial content and function in benign tissue and in high-grade epithelial ovarian carcinoma (EOC) in parallel with exploratory analyses of biobehavioral factors. First, analysis of a publicly-available database (n = 1435) showed that gene expression of specific mitochondrial proteins in EOC is associated with survival. Quantifying multiple biochemical and molecular markers of mitochondrial content and function in tissue from 51 patients with benign ovarian masses and 128 patients with high-grade EOC revealed that compared to benign tissue, EOCs exhibit 3.3-8.4-fold higher mitochondrial content and respiratory chain enzymatic activities (P < 0.001) but similar mitochondrial DNA (mtDNA) levels (- 3.1%), documenting abnormal mitochondrial phenotypes in EOC. Mitochondrial respiratory chain activity was also associated with interleukin-6 (IL-6) levels in ascites. In benign tissue, negative biobehavioral factors were inversely correlated with mitochondrial content and respiratory chain activities, whereas positive biobehavioral factors tended to be positively correlated with mitochondrial measures, although effect sizes were small to medium (r = - 0.43 to 0.47). In contrast, serous EOCs showed less pronounced biobehavioral-mitochondrial correlations. These results document abnormal mitochondrial functional phenotypes in EOC and warrant further research on the link between biobehavioral factors and mitochondria in cancer.

Early stopping in clinical PET studies: How to reduce expense and exposure.

Clinical positron emission tomography (PET) research is costly and entails exposing participants to radioactivity. Researchers should therefore aim to include just the number of subjects needed to fulfill the purpose of the study. In this tutorial we show how to apply sequential Bayes Factor testing in order to stop the recruitment of subjects in a clinical PET study as soon as enough data have been collected to make a conclusion. By using simulations, we demonstrate that it is possible to stop a study early, while keeping the number of erroneous conclusions low. We then apply sequential Bayes Factor testing to a real PET data set and show that it is possible to obtain support in favor of an effect while simultaneously reducing the sample size with 30%. Using this procedure allows researchers to reduce expense and radioactivity exposure for a range of effect sizes relevant for PET research.

Evaluation of surgical fellows' laparoscopic performance using Global Operative Assessment of Laparoscopic Skills (GOALS).

BACKGROUND: The acquisition of technical skills is one of the fundamental goals of postgraduate surgical training; however, validation and utilization of objective tools to assess the technical skills of trainees remains elusive. The objectives of this project are to develop models to identify predictive factors for fellow performance, validate the Global Operative Assessment of Laparoscopic Skills (GOALS) as an assessment tool for laparoscopic skills, and to define the learning curve for complex laparoscopic gastrointestinal surgery. METHODS: Using previously recorded data from a centralized database of the Fellowship Council, we analyzed the voluntarily submitted performance scores of surgical fellows for three complex laparoscopic gastrointestinal operations: Roux-en-Y gastric bypass, LapBand placement, and Nissen fundoplication. We analyzed previous experience with complex cases, previous experience with the same type of case, case difficulty, and time of year in the fellowship as potential predictors of performance. Performance scores throughout the fellowship year were graphed to create learning curves for overall performance and each of five domains of performance. RESULTS: Ninety-eight performance assessments were submitted for 31 unique fellows. Overall performance (p < 0.01), bimanual dexterity (p < 0.01), efficiency (p < 0.01), and autonomy (p < 0.01) all improved significantly throughout the course of the fellowship year. Performance in the domains of depth perception and tissue handling improved, but the improvement did not reach statistical significance. Three predictor variables were significantly related to performance scores. CONCLUSIONS: This study documents that GOALS is able to differentiate novice fellows from graduating fellows and established construct validity. Models developed and tested confirmed that previous experience, case difficulty, and length of time as a fellow impacted performance.