Single access laparoscopic total colectomy for severe refractory ulcerative colitis

BACKGROUND Single port laparoscopic surgery allows total colectomy and end ileostomy for medically uncontrolled ulcerative colitis solely via the stoma site incision.While intuitively appealing,there is sparse evidence for its use beyond feasibility.AIM To examine the usefulness of single access laparoscopy(SAL)in a general series experience of patients sick with ulcerative colitis.METHODS All patients presenting electively,urgently or emergently over a three-year period under a colorectal specialist team were studied.SAL was performed via the stoma site on a near-consecutive basis by one surgical team using a“surgical glove port”allowing group-comparative and case-control analysis with a contemporary cohort undergoing conventional multiport surgery.Standard,straight rigid laparoscopic instrumentation were used without additional resource.RESULTS Of 46 consecutive patients requiring surgery,39(85%)had their procedure begun laparoscopically.27(69%)of these were commenced by single port access with an 89%completion rate thereafter(three were concluded by multi-trocar laparoscopy).SAL proved effective in comparison to multiport access regardless of disease severity providing significantly reduced operative access costs(>100€case)and postoperative hospital stay(median 5 d vs 7.5 d,P=0.045)without increasing operative time.It proved especially efficient in those with preoperative albumin>30 g/dL(n=20).Its comparative advantages were further confirmed in ten pairs case-matched for gender,body mass index and preoperative albumin.SAL outcomes proved durable in the intermediate term(median follow-up=20 mo).CONCLUSION Single port total colectomy proved useful in planned and acute settings for patients with medically refractory colitis.Assumptions regarding duration and cost should not be barriers to its implementation.

SHEsis PCA: A GPU-Based Software to Correct for Population Stratification that Efficiently Accelerates the Process for Handling Genome-Wide Datasets

Population stratification is a problem in genetic association studies because it is likely to highlight loci that underlie the population structure rather than disease-related loci. At present, principal component analysis （PCA） has been proven to be an effective way to correct for population stratification. However, the conventional PCA algorithm is time-consuming when dealing with large datasets. We developed a Graphic processing unit （GPU）-based PCA software named SHEsisPCA （http：//analysis.bio-x.cn/SHEsisMain.htm） that is highly parallel with a highest speedup greater than 100 compared with its CPU version. A cluster algorithm based on X-means was also implemented as a way to detect population subgroups and to obtain matched cases and controls in order to reduce the genomic inflation and increase the power. A study of both simulated and real datasets showed that SHEsisPCA ran at an extremely high speed while the accuracy was hardly reduced. Therefore, SHEsisPCA can help correct for population stratification much more efficiently than the conventional CPU-based algorithms.