[Overlap esophagojejunostomy with multi-mode modifications in totally laparoscopic total gastrectomy: safety and feasibility of 152 cases from a single center]

Objective: Currently, the Overlap anastomosis is one of the most favored reconstruction methods of intracorporeal esophagojejunostomy (EJS). Despite many advantages of the method, it remains some shortcomings to be improved when it comes to the retraction of the esophagus stump, the insertion of the anvil fork of the linear stapler into a "pseudo" lumen, and the closure of the common entry hole. This study aims to investigate the safety and feasibility of a multi-mode modified Overlap anastomosis. Methods: A descriptive case series study was conducted. Medical records of 152 consecutive patients who underwent totally laparoscopic total gastrectomy (TLTG) with our multi-mode modified Overlap EJS method by the same surgical team at our department from February 2017 to June 2020 were retrospectively analyzed. The multi-mode modified Overlap method mainly included (1) After ensuring the safety of tumor resection margin (proximal margin was at least 3 cm from the tumor), the esophagus was partially transected from left to right (with 5-8 mm width esophagus continuation). The specimen was then placed in a plastic bag which was tied up at the mouth using strings with a part of the esophageal wall poking through. Then the plastic bag containing the specimen was transferred to the right lumbar region, while the patient's body position was adjusted so that the abdominal esophagus could be pulled by the gravity of the specimen. (2) Using the "three-direction traction" method. The esophageal lumen was properly exposed, then guided by the gastric tube, the anvil fork was accurately placed into the esophageal lumen for completing the side-to-side EJS. (3) The 3-0 barbed suture was used in the closure of the common entry hole of the stapler from dorsally to ventrally with simple one-layer continuous suture (the stitch going from inside to inside) followed by continuous Lembert's suture (the stitch going from outside to outside). Combined with clinicopathological characteristics, the perioperative outcomes and postoperative complications of the whole group were analyzed and evaluated. Results: The study cohort included 129 men and 23 women, with a mean age of (60.2±9.1) years and a mean body mass index (BMI) of (23.2±3.1) kg/m(2). Of the 152 patients, 23 patients (15.1%) had a history of previous abdominal surgery; dentate line was invaded by tumor in 21 patients (13.8%). The mean length of the proximal resection margin was (3.3±0.3) cm and the postoperative pathological examination indicated negative resection margin tumor. The mean operative time and anastomotic time were (302.1±39.9) minutes and (29.8±5.4) minutes, respectively. The mean estimated blood loss was (87.9±46.4) ml. The mean length of postoperative hospital stay was (12.3±7.3) days. The overall severe postoperative complications (Clavien-Dindo ≥ II) occurred in 22 patients (14.5%). Six cases of pancreatic leakage were successfully recovered by adequate drainage, inhibition of pancreatic exocrine secretion and nutritional support. Ten cases of pneumonia and three cases of abdominal infection were cured with anti-infection and physical therapy. Two patients developed anastomotic leakage postoperatively. One case was caused by excessive tension of the Roux loop of the jejunum and excessive opening on the side of the jejunum after side-to-side anastomosis, and the other case was caused by an accidental intraoperative occurrence of "nasogastric tube stapled to the side-to-side anastomosis". Both of them recovered after conservative treatment including adequate drainage, anti-infection, and adequate nutritional support. One patient underwent immediate open surgery because of Peterson's hernia 7 days after TLTG, and the patient died due to extensive small bowel necrosis. Conclusions: Multi-mode modified overlap method simplifies the operation and reduces the difficulty of EJS. It is a safe and feasible method for EJS.

Identification of differentially expressed genes at two key endosperm development stages using two maize inbreds with large and small grain and integration with detected QTL for grain weight

Maize endosperm accounts for more than 80% of the grain weight. Cell division and grain filling are the two key stages for endosperm development. Previous studies showed that gene expression during differential stages in endosperm development is greatly different. However, information on systematic identification and characterization of the differentially expressed genes between the two stages are limited. In this study, suppression subtractive hybridization (SSH) was used to generate four subtracted cDNA libraries for the two stages using two maize inbreds with large and small grain. Totally, 4,784 differentially expressed sequence tags (ESTs) were sequenced and 902 were non-redundant, which consisted of 344 unique ESTs. Among them 192 had high sequence similarity to the GenBank entries and represent diverse of functional categories, such as metabolism, cell growth/division, transcription, signal transduction, protein destination/storage, protein synthesis and others. The expression patterns of 75.7% SSH-derived cDNAs were confirmed by reverse Northern blot and semi-quantitative reverse transcription polymerase chain reaction, and exhibited the similar results (75.0%). Genes differentially expressed between two key stages for the two inbreds were involved in diverse physiological process pathway, which might be responsible for the formation of grain weight. 43.8% (70 of the 160 unique ESTs) of the identified ESTs were assigned to 39 chromosome bins distributed over all ten maize chromosomes. Eleven ESTs were found to co-localize with previous detected QTLs for grain weight, which might be considered as the candidate genes of grain weight for further study.

Identification of trait-improving quantitative trait loci for grain yield components from a dent corn inbred line in an advanced backcross BC2F2 population and comparison with its F2:3 population in popcorn

Normal maize germplasm could be used to improve the grain yield of popcorn inbreds. Our first objective was to locate genetic factors associated with trait variation and make first assessment on the efficiency of advanced backcross quantitative trait locus (AB-QTL) analysis for the identification and transfer of favorable QTL alleles for grain yield components from the dent corn inbred. A second objective was to compare the detection of QTL in the BC2F2 population with results using F(2:3) lines of the same parents. Two hundred and twenty selected BC2F2 families developed from a cross between Dan232 and an elite popcorn inbred N04 were evaluated for six grain yield components under two environments, and genotyped by means of 170 SSR markers. Using composite interval mapping (CIM), a total of 19 significant QTL were detected. Eighteen QTL had favorable alleles contributed by the dent corn parent Dan232. Sixteen of these favorable QTL alleles were not in the same or near marker intervals with QTL for popping characteristics. Six QTL were also detected in the F(2:3) population. Improved N04 could be developed from 210 and 208 families with higher grain weight per plant and/or 100-grain weight, respectively, and 35 families with the same or higher popping expansion volume than N04. In addition, near isogenic lines containing detected QTL (QTL-NILs) for grain weight per plant and/or 100-grain weight could be obtained from 12 families. Our study demonstrated that the AB-QTL method can be applied to identify and manipulate favorable QTL alleles from normal corn inbreds and combine QTL detection and popcorn breeding efficiently.

Identification of trait-improving quantitative trait loci for grain yield components from a dent corn inbred line in an advanced backcross BC2F2 population and comparison with its F2:3 population in popcorn

Normal maize germplasm could be used to improve the grain yield of popcorn inbreds. Our first objective was to locate genetic factors associated with trait variation and make first assessment on the efficiency of advanced backcross quantitative trait locus (AB-QTL) analysis for the identification and transfer of favorable QTL alleles for grain yield components from the dent corn inbred. A second objective was to compare the detection of QTL in the BC2F2 population with results using F(2:3) lines of the same parents. Two hundred and twenty selected BC2F2 families developed from a cross between Dan232 and an elite popcorn inbred N04 were evaluated for six grain yield components under two environments, and genotyped by means of 170 SSR markers. Using composite interval mapping (CIM), a total of 19 significant QTL were detected. Eighteen QTL had favorable alleles contributed by the dent corn parent Dan232. Sixteen of these favorable QTL alleles were not in the same or near marker intervals with QTL for popping characteristics. Six QTL were also detected in the F(2:3) population. Improved N04 could be developed from 210 and 208 families with higher grain weight per plant and/or 100-grain weight, respectively, and 35 families with the same or higher popping expansion volume than N04. In addition, near isogenic lines containing detected QTL (QTL-NILs) for grain weight per plant and/or 100-grain weight could be obtained from 12 families. Our study demonstrated that the AB-QTL method can be applied to identify and manipulate favorable QTL alleles from normal corn inbreds and combine QTL detection and popcorn breeding efficiently.