[Feasibility, safety and long-term efficacy of laparoscopic total gastrectomy combined with distal pancreaticosplenectomy for T4b gastric cancer]

Objective: To explore the feasibility, safety and long-term efficacy of laparoscopic total gastrectomy combined with distal pancreaticosplenectomy for the treatment of T4b gastric cancer. Methods: A retrospective cohort study was performed. Clinical data of consecutive patients with T4b gastric cancer invading pancreatic tail undergoing laparoscopic or open total gastrectomy combined with distal pancreaticosplenectomy from January 2010 to December 2014 were analyzed retrospectively. Enrollment criteria: (1) primary gastric cancer confirmed by pathology as T4b adenocarcinoma; (2) chest+abdominal+pelvic enhanced CT indicated cancer invading pancreatic tail without distant metastasis, and R0 resection was evaluated as feasible before operation; (3) physical status was ECOG score 0 to 2, and was tolerant to operation. Patients with peritoneal implant metastasis and tumor invasion of other organs during operation, or changes in surgical methods for other reasons were excluded. All the operations were performed by the same surgical team, which had the experiences of more than 100 cases of laparoscopic and 100 cases of open radical gastrectomy with D2 lymph node dissection. The choice of surgical procedure was discussed by the surgeon and the patient, and decided according to the patient's intension. Patients were divided into the laparoscopic group and open group according to the surgical method. Intraoperative and perioperative findings were compared between the two groups. The 3-year disease-free survival rate were analyzed with Kaplan-Meier survival curve and compared by using log-rank test. Results: A total of 37 consecutive patients were enrolled, including 21 in the laparoscopic group and 16 in the open group, and no one receiving laparoscopic procedure was converted to open surgery. The baseline data of two groups were comparable (all P>0.05). Compared with the open group, the laparoscopic group had significantly longer operation time [(264.0±35.1) minutes vs. (226.6±49.9) minutes, t=2.685, P=0.011], significantly less intraoperative blood loss [(65.7±37.4) ml vs. (182.2±94.6) ml, t=-4.658, P<0.001], significantly shorter time to postoperative flatus [(2.8±0.7) days vs. (4.1±0.7) days, t=-5.776, P<0.001] and significantly shorter postoperative hospital stay [(13.3±2.8) days vs. (16.6±4.3) days, t=-2.822, P=0.008]. Morbidity of postoperative complications, including anastomotic leakage, pancreatic fistula, abdominal abscess, intraperitoneal hemorrhage and duodenal stump leakage, in two groups was similar [19.0% (4/21) vs. 4/16, P=0.705]. There were no cases of anastomotic bleeding or stenosis. The 30-day postoperative mortality was 0 in the laparoscopic group and 1/16 in the open group, respectively (P=0.432). The 3-year disease-free survival rates were 38.1% and 37.5% in the laparoscopic and open group, respectively (P=0.751). Conclusion: Laparoscopic total gastrectomy combined with distal pancreaticosplenectomy performed by experienced surgeons for T4b gastric cancer is safe and effective.

[Establishment and its application of a reporter-based screening model for discovering new ligands of estrogen receptor alpha subtypes]

AIM

To establish a sensitive and efficient reporter gene based screening model and use it to screen compounds for discovering new ligands of estrogen receptor alpha subtype.

METHODS

A recombinant Epstein-Barr virus episomal vector (pMT/ERE-CAT) was constructed by inserting a synthetic sequence composed of five estrogen response elements upstream of promoter and a chloramphenicol acetyltransferase (CAT) gene downstream of promoter. pMT/ERE-CAT was transfected into HepG2 cells expressing estrogen receptor alpha subtype (ER +HepG2). Hygromycin (200 micrograms.mL-1) was added 48 h after transfection for selection. One stably transfected clone was isolated and used to screen compounds for activity of stimulating CAT gene expression using colorimetric CAT assay.

RESULTS

In the ER +HepG2 cells, the expression of CAT gene was induced by estradiol. A dose-dependent expression of CAT gene with half-maximal induction at 0.07 nmol.L-1 was observed. The ER +HepG2 cell was used to screen compounds for activity of stimulating CAT gene expression. Resveratrol was found to produce a maximal level of induction (1.75 times of estradiol). In vitro radiation survival experiment showed that the radioprotection activity of resveratrol (D0 = 3.18 Gy) is stronger than that of estradiol (D0 = 2.59 Gy).

CONCLUSION

Vector pMT/ERE-CAT was used to generate stably transfected ER +HepG2 cell lines. The cell lines can be used to screen compounds for estrogen activity by testing extracts of cells grown in microtiter wells directly using colorimetric CAT assay. This system should provide an efficient method for screening and analyzing the activity of large numbers of ligands of estrogen receptor.