Hyperechoic demarcation line between a tumor and the muscularis propria layer as a marker for deciding the endoscopic treatment of gastric submucosal tumor

Minimally invasive endoscopic resection has been rapidly adopted as a new technique for treating patientswith gastric submucosal tumors （SMTs） originating in the muscularis propria （MP） layer. This study was conducted toevaluate the information obtained from endoscopic ultrasonography （EUS） to determine the appropriate endoscopicdissection method for treating SMTs originating in the MP layer. Between February 2014 and May 2016, a total of 50patients with gastric SMTs originating in the MP layer were enrolled in this study. The clinical features of the patientsand their endoscopic, EUS, and histopathologic findings, as well as their postoperative follow-up data, were analyzedin this retrospective study. The mean age of the patients was （55.0±10.2） years, and the male/female ratio was 17：33.Endoscopic submucosal dissection （ESD） was performed on 43 patients and an endoscopic full-thickness resection（EFR） was performed on seven patients. The most frequent location for an SMT was in the upper body region of thestomach （n=16）, and the most common pathological diagnosis was a gastrointestinal stromal tumor （GIST） （n=32）.The overall rates for complete resection were 95.3% （41/43） and 100.0% （7/7） when the SMTs were treated by ESDand EFR, respectively. The presence of a complete tumor capsule was significantly associated with a complete re-section （P=0.001）. Of the cases treated by ESD, nine patients developed perforation, one of whom required laparo-scopic surgery. The remaining patients were closed with clips or purse-string sutures. The presence of an MP2-typetumor （P=0.018） and a wide connection with the MP layer （P=0.044） were significantly associated with perforation. Apreoperative evaluation of the integrity and the location of a tumor capsule and the length of the tumor connection withthe MP layer by EUS can improve the complete resection rate and reduce the occurrence of intraoperative complica-tions. Tumors with a complete capsule originating from the superficial MP layer or with a narrow connection with theMP layer are appropriate candidates for treatment by ESD.

Simultaneous detection and characterization of toxigenic Clostridium difficile directly from clinical stool specimens

We employed a multiplex polymerase chain reaction （PCR） coupled with capillary electrophoresis （mPCR-CE） targeting six Clostridium difficile genes, including tPi, tcdA, tcdB, cdtA, cdtB, and a deletion in tcdC for simultaneous detection and characterization of toxigenic C. difficile directly from fecal specimens. The mPCR-CE had a limit of detection of 10 colony-forming units per reaction with no cross-reactions with other related bacterial genes. Clinical validation was performed on 354 consecutively collected stool specimens from patients with suspected C. difficile infection and 45 isolates. The results were compared with a reference standard combined with BD MAX Cdiff, real-time cell analysis assay （RTCA）, and mPCR-CE. The toxigenic C. difficile species were detected in 36 isolates and 45 stool specimens by the mPCR-CE, which provided a positive rate of 20.3% （81/399）. The mPCR-CE had a specificity of 97,2% and a sensitivity of 96.0%, which was higher than RTCA （χ^2 = 5.67, P = 0.017） but lower than BD MAX Cdiff （P = 0.245）. Among the 45 strains, 44 （97.8%） were determined as non- ribotype 027 by the mPCR-CE, which was fully agreed with PCR ribotyping. Even though ribotypes 017 （n = 8, 17.8%）, 001 （n = 6, 13.3%）, and 012 （n = 7, 15.6%） were predominant in this region, ribotype 027 was an important genotype monitored routinely. The mPCR-CE provided an alternative diagnosis tool for the simultaneous detection of toxigenic C. difficile in stool and potentially differentiated between RT027 and non-RT027.