Effects of a retention interval and refresher session on intracorporeal suturing and knot tying skill and mental workload.

BACKGROUND: The effects of refraining from practice for different intervals on laparoscopic suturing and mental workload was assessed with a secondary task developed by the authors. We expected the inability to practice to produce a decrease in performance on the suturing, knot tying, and secondary task and skills to rebound after a single refresher session. METHODS: In total, 22 surgical assistant and premedical students trained to Fundamentals of Laparoscopic Surgery proficiency in intracorporeal suturing and knot tying were assessed on that task using a secondary task. Participants refrained from practicing any Fundamentals of Laparoscopic Surgery tasks for 1 or 5 months. At the time of their return, they were assessed immediately on suturing and knot tying with the secondary task, practiced suturing and knot tying for 40 minutes, and then were reassessed. RESULTS: The mean suture times from the initial reassessment were greater than the proficiency times but returned to proficiency levels after one practice session, F(2, 40) = 14.5, P < .001, partial η2 = .420. Secondary task scores mirrored the results of suturing time, F(2, 40) = 6.128, P < .005, partial η2 = .235, and were moderated by retention interval. CONCLUSION: When participants who reached proficiency in suturing and knot tying were reassessed after either 1or 5 months without practice, their performance times increased by 35% and secondary task scores decreased by 30%. These deficits, however, were nearly reversed after a single refresher session.

Intracorporeal suturing: Transfer from Fundamentals of Laparoscopic Surgery to cadavers results in substantial increase in mental workload.

INTRODUCTION: A spatial secondary task developed by the authors was used to measure the mental workload of the participant when transferring suturing skills from a box simulator to more realistic surgical conditions using a fresh cadaver. We hypothesized that laparoscopic suturing on genuine bowel would be more challenging than on the Fundamentals of Laparoscopic Surgery (FLS)-simulated bowel as reflected in differences on both suturing and secondary task scores. METHODS: We trained 14 surgical assistant students to FLS proficiency in intracorporeal suturing. Participants practiced suturing on the FLS box for 30 minutes and then were tested on both the FLS box and the bowel of a fresh cadaver using the spatial, secondary dual-task conditions developed by the authors. RESULTS: Suturing times increased by >333% when moving from the FLS platform to the cadaver F(1,13) = 44.04, P < .001. The increased completion times were accompanied by a 70% decrease in secondary task scores, F(1,13) = 21.21, P < .001. CONCLUSION: The mental workload associated with intracorporeal suturing increases dramatically when trainees transfer from the FLS platform to human tissue under more realistic conditions of suturing. The increase in mental workload is indexed by both an increase in suturing times and a decrease in the ability to attend to the secondary task.

Signaling cascades activated upon antibody cross-linking of myelin oligodendrocyte glycoprotein: potential implications for multiple sclerosis.

Antibody-induced demyelination is an important component of pathology in multiple sclerosis. In particular, antibodies to myelin oligodendrocyte glycoprotein (MOG) are elevated in multiple sclerosis patients, and they have been implicated as mediators of demyelination. We have shown previously that antibody cross-linking of MOG in oligodendrocytes results in the repartitioning of MOG into glycosphingolipid-cholesterol membrane microdomains ("lipid rafts"), followed by changes in the phosphorylation of specific proteins, including dephosphorylation of beta-tubulin and the beta subunit of the trimeric G protein and culminating in rapid and dramatic morphological alterations. In order to further elucidate the mechanism of anti-MOG-mediated demyelination, we have carried out a proteomic analysis to identify the set of proteins for which the phosphorylation states or expression levels are altered upon anti-MOG treatment. We demonstrate that treatment of oligodendrocytes with anti-MOG alone leads to an increase in calcium influx and activation of the MAPK/Akt pathways that is independent of MOG repartitioning. However, further cross-linking of anti-MOG.MOG complexes with a secondary anti-IgG results in the lipid raft-dependent phosphorylation of specific proteins related to cellular stress response and cytoskeletal stability. Oligodendrocyte survival is not compromised by these treatments. We discuss the possible significance of the anti-MOG-induced signaling cascade in relation to the initial steps of MOG-mediated demyelination.