[Risk factors for complications of endoscopic full-thickness resection of upper gastrointestinal submucosal tumors].

Objective: To analyze the risk factors for complications of endoscopic full-thickness resection (EFTR) of upper gastrointestinal submucosal tumors (SMTs). Methods: This was a retrospective observational study. The indications for EFTR included: (1) SMTs originating from the muscularis propria layer and growing out of the cavity or infiltrating the deep part of the muscularis propria layer; (2) SMTs diameter <5 cm; and (3) tumor identified as closely adherent to the serous layer during endoscopic submucosal dissection or endoscopic mucosal resection. This study included patients with SMTs originating from the muscularis propria layer in upper digestive tract, diagnosed preoperatively by endoscopic ultrasonography or computed tomography, who were successfully treated with EFTR. Those with incomplete clinical data were excluded. The clinical data of 154 patients with upper gastrointestinal SMTs who underwent EFTR at the Department of Gastroenterology, First Affiliated Hospital of Soochow University from January 2016 to January 2022 were retrospectively analyzed. Post-EFTR complications (such as delayed perforation, delayed bleeding, and postoperative infection, including electrocoagulation syndrome) were monitored and the risk factors for them were analyzed. Results: Among the 154 study patients, 33 (21.4%) developed complications, including delayed bleeding in three (1.9%), delayed perforation in two (1.3%), and postoperative infection in 28 (18.2%). One patient with bleeding was classified as having a major complication (hospitalized for more than 10 days because of complication). According to univariate analysis, complication was associated with tumor diameter >15 mm, operation time >90 minutes, defect closure method(purse string suture), and diameter of resected specimen ≥20 mm (all P<0.05). Multivariate logistic regression analysis showed that operation time >90 minutes (OR=6.252, 95%CI: 2.530-15.446, P<0.001) and tumor diameter >15 mm (OR=4.843, 95%CI: 1.985-11.817, P=0.001) were independent risk factors for complications after EFTR in patients with upper gastrointestinal SMTs. The independent risk factors for postoperative infection in these patients were operation time>90 minutes (OR=4.993, 95%CI:1.964-12.694, P=0.001) and purse string suture (OR=7.142, 95%CI: 1.953-26.123, P=0.003). Conclusion: Patients with upper gastrointestinal SMTs undergoing EFTR with tumor diameter >15 mm or operation time >90 minutes have a significantly increased risk of postoperative complications. Postoperative monitoring is important for these patients with SMTs.

High efficient encapsulation of plasmid DNA in PLGA microparticles by organic phase self-emulsification.

To overcome the drawbacks of encapsulating plasmid DNA (pDNA) in poly (D,L-lactic-co-glycolic acid) (PLGA) by water-in-oil-in-water double-emulsion solvent-evaporation method, we have developed a novel procedure for encapsulating pDNA in PLGA microparticles called DNA organic phase self-emulsification (DOPSM). This method was based on both the extraction plasmid DNA from aqueous phase into organic phase and the spontaneous emulsification DNA in organic phase by solvent diffusion method. The efficiency of extraction plasmid DNA into organic phase is 99% and the concentration of pDNA in organic phase is up to 2.4 mg/ml. The efficiency of microencapsulation of plasmid DNA in PLGA is up to 76% and can be enhanced by lowering the pH of aqueous solution of emulsion. The microparticles size of PLGA of pDNA is in a narrow range of 1-2 microm. This procedure does not involve the high mechanical energy to emulsify which may damage the integrity of pDNA. This method can be applied to encapsulate the pDNA into microparticles of other biocompatible polymers with high efficiency.