Total mesorectal excision: assessment of the laparoscopic approach.

PURPOSE: Total mesorectal excision offers the lowest reported rates of local recurrence for rectal cancer; however, the ability to perform total mesorectal excision laparoscopically remains unproven. The aim of this study was to assess the feasibility and adequacy of a totally laparoscopic total mesorectal excision for rectal cancer. METHODS: A prospective review of all patients undergoing laparoscopic-assisted surgery for rectal cancer by a single surgeon was undertaken. These were compared with a control group undergoing open rectal resections by another colorectal consultant in the unit (n = 22). Comparison of total specimen length, longitudinal and radial excision margins, and lymph node yield was made between groups. RESULTS: Of 42 laparoscopic-assisted rectal resections attempted, 14 (33 percent) were converted to open procedures and six had their dissection completed open. One resection was considered noncurative. Twenty-one total mesorectal excisions (50 percent) were completed totally laparoscopically. No significant difference was detected between groups for specimen length, radial margin, or lymph node yield. Longitudinal margin of excision was longer in the laparoscopic group (4 (3.5-5) vs. 2.5 (1.05-3.5) cm; P = 0.02, Mann-Whitney). Operating time was significantly longer in the laparoscopic group (180 (168-218) vs. 125 (104-144) minutes; P = 0.003, Mann-Whitney). Data are medians (interquartile ranges). Four patients in the laparoscopic-assisted group had clinical anastomotic leakage vs. one in the open group (P = 0.329, Fisher's exact test). At median follow-up of 38 (range, 6-53) months, one local recurrence had occurred in each group and crude mortality rates were 29 and 23 percent in the laparoscopic-assisted and open groups, respectively (P = 0.736, Fisher's exact test). CONCLUSION: Totally laparoscopic excision of the mesorectum is feasible in 50 percent of patients and where possible yields histologic parameters comparable to open surgery. Early survival and recurrence figures also appear to be comparable.

Protein phosphatase 1 and 2A in tick salivary glands as assessed by responses to okadaic acid.

Crude protein phosphatase activity was inhibited 80% by nanomolar okadaic acid (OA) in salivary glands of unfed ticks but only 40% in salivary glands of feeding ticks. An additional 40% of protein phosphatase was inhibited by micromolar OA in the salivary glands of feeding ticks but only 10% in salivary glands of unfed ticks. Cyclic AMP and OA alone or together increased the phosphorylation of multiple proteins in a plasma membrane-enriched 900 g supernatant fraction of tick salivary glands. Exogenous cyclic AMP stimulated increased incorporation of phosphate into proteins with approximate molecular weights of 109, 70, 64, 51, 48, 42 and 18.5 kDa. Micromolar OA in the absence of exogenous cyclic AMP stimulated increased incorporation of phosphate into proteins with apparent molecular weights of 109, 93, 74.5, 70, 51, 48, 42 and 18.5 kDa. Cyclic AMP and OA (10(-6) and 10(-9) M) stimulated significantly greater phosphorylation of an 18.5 kDa mol. wt protein above that observed in response to stimulation by OA (10(-6) and 10(-9) M) or exogenous cyclic AMP alone. Micromolar okadaic acid inhibited the amount and number of proteins but not volume of saliva secreted by whole ticks in response to stimulation by DA and theophylline. However, micromolar and nanomolar okadaic acid inhibited the ability of dopamine to stimulate fluid secretion by isolated salivary glands. Overall, the data support the existence of type 1 and 2A protein phosphatases in tick salivary glands and a role for protein phosphatases in modulating tick salivary secretion.