Assessing the value of the SimPraxis laparoscopic cholecystectomy trainer.

BACKGROUND AND OBJECTIVES: Our aim was to determine whether the SimPraxis Laparoscopic Cholecystectomy Trainer is an effective adjunct for training both junior and senior surgical residents. METHODS: During the 2009-2010 academic year, 20 of 27 surgical residents at our institution completed training with the SimPraxis Laparoscopic Cholecystectomy Trainer. These 20 residents took an identical 25-question pre- and posttest prepared in-house by a senior laparoscopic surgeon, based on the SimPraxis Laparoscopic Cholecystectomy program content. Included within the SimPraxis program is a multiple data point scoring system. For our reporting purposes, we divided the residents into 2 groups, junior (PGY 1-2; n = 11) and senior (PGY 3-5; n = 9). RESULTS: The junior residents demonstrated a statistically significant improvement in their post-test scores (P = .001). On the contrary, the senior residents showed nonstatistically significant minor improvement in their examination scores (P = .09). While, the pretest scores were significantly higher for the senior residents compared with the junior residents (P = .003), the post-test scores were nonsignificantly different between the senior vs. the junior residents (P = .07). There was no significant difference between the time it took junior and senior residents to complete the SimPraxis program. CONCLUSION: Our data demonstrate that junior residents benefitted the most from the SimPraxis training program. Requiring junior surgical residents to complete both skills and cognitive training programs may be an effective adjunct in preparation for participation in laparoscopic cholecystectomy procedures.

Manganese superoxide dismutase enhances the invasive and migratory activity of tumor cells.

Clinically significant elevations in the expression of manganese superoxide dismutase (Sod2) are associated with an increased frequency of tumor invasion and metastasis in certain cancers. The aim of this study was to examine whether increases in Sod2 activity modulate the migratory potential of tumor cells, contributing to their enhanced metastatic behavior. Overexpression of Sod2 in HT-1080 fibrosarcoma cells significantly enhanced their migration 2-fold in a wound healing assay and their invasive potential 3-fold in a transwell invasion assay. Severity of invasion was directly correlated to Sod2 expression levels and this invasive phenotype was similarly observed in 253J bladder tumor cells, in which Sod expression resulted in a 3-fold increase in invasion compared with controls. Further, migration and invasion of the Sod2-expressing cells was inhibited following overexpression of catalase, indicating that the promigratory/invasive phenotype of Sod2-expressing cells is H(2)O(2) dependent. Sod2 overexpression was associated with a loss of vinculin-positive focal adhesions that were recovered in cells coexpressing catalase. Tail vein injections of Sod2-GFP-expressing HT-1080 cells in NCR nude mice led to the development of pulmonary metastatic nodules displaying high Sod2-GFP expression. Isolated tumors were shown to retain high Sod2 activity in culture and elevated levels of the matrix degrading protein matrix metalloproteinase-1, and a promigratory phenotype was observed in a population of cells growing out from the tumor nodule. These findings suggest that the association between increased Sod2 activity and poor prognosis in cancer can be attributed to alterations in their migratory and invasive capacity.