L-glutamic acid is the world's largest bulk amino acid product that is widely used in the food, pharmaceutical and chemical industries. Using Corynebacterium glutamicum G01 as the starting strain, the fermentation by-product alanine content was firstly reduced by knocking out the gene encoding alanine aminotransferase (alaT), a major by-product related to alanine synthesis. Secondly, since the α-ketoglutarate node carbon flow plays an important role in glutamate synthesis, the ribosome-binding site (RBS) sequence optimization was used to reduce the activity of α-ketoglutarate dehydrogenase and enhance the glutamate anabolic flow. The endogenous conversion of α-ketoglutarate to glutamate was also enhanced by screening different glutamate dehydrogenase. Subsequently, the glutamate transporter was rationally desgined to improve the glutamate efflux capacity. Finally, the fermentation conditions of the strain constructed using the above strategy were optimized in 5 L fermenters by a gradient temperature increase combined with a batch replenishment strategy. The glutamic acid production reached (135.33±4.68) g/L, which was 41.2% higher than that of the original strain (96.53±2.32) g/L. The yield was 55.8%, which was 11.6% higher than that of the original strain (44.2%). The combined strategy improved the titer and the yield of glutamic acid, which provides a reference for the metabolic modification of glutamic acid producing strains.
Glutamic Acid ; Corynebacterium glutamicum/genetics* ; Ketoglutaric Acids ; Metabolic Engineering ; Alanine

γ-aminobutyric acid can be produced by a one-step enzymatic reaction catalyzed by glutamic acid decarboxylase. The reaction system is simple and environmentally friendly. However, the majority of GAD enzymes catalyze the reaction under acidic pH at a relatively narrow range. Thus, inorganic salts are usually needed to maintain the optimal catalytic environment, which adds additional components to the reaction system. In addition, the pH of solution will gradually rise along with the production of γ-aminobutyric acid, which is not conducive for GAD to function continuously. In this study, we cloned the glutamate decarboxylase LpGAD from a Lactobacillus plantarum capable of efficiently producing γ-aminobutyric acid, and rationally engineered the catalytic pH range of LpGAD based on surface charge. A triple point mutant LpGAD^{S24R/D88R/Y309K} was obtained from different combinations of 9 point mutations. The enzyme activity at pH 6.0 was 1.68 times of that of the wild type, suggesting the catalytic pH range of the mutant was widened, and the possible mechanism underpinning this increase was discussed through kinetic simulation. Furthermore, we overexpressed the Lpgad and Lpgad^{S24R/D88R/Y309K} genes in Corynebacterium glutamicum E01 and optimized the transformation conditions. An optimized whole cell transformation process was conducted under 40 ℃, cell mass (OD₆₀₀) 20, 100 g/L l-glutamic acid substrate and 100 μmol/L pyridoxal 5-phosphate. The γ-aminobutyric acid titer of the recombinant strain reached 402.8 g/L in a fed-batch reaction carried out in a 5 L fermenter without adjusting pH, which was 1.63 times higher than that of the control. This study expanded the catalytic pH range of and increased the enzyme activity of LpGAD. The improved production efficiency of γ-aminobutyric acid may facilitate its large-scale production.
Glutamate Decarboxylase/genetics* ; Lactobacillus plantarum/genetics* ; Catalysis ; gamma-Aminobutyric Acid ; Hydrogen-Ion Concentration ; Glutamic Acid

Chest trauma is one of the most common injuries. Venous thromboembolism (VTE) as a common complication of chest trauma seriously affects the quality of patients′ life and even leads to death. Although there are some consensus and guidelines on the prevention and treatment of VTE at home and abroad, the current literatures lack specificity considering the diagnosis, treatment and prevention of VTE in patients with chest trauma have their own characteristics, especially for those with blunt trauma. Accordingly, China Chest Injury Research Society and editorial board of Chinese Journal of Traumatology organized relevant domestic experts to jointly formulate the Chinese expert consensus on the diagnosis, treatment and prevention of chest trauma venous thromboembolism associated with chest trauma (2022 version). This consensus provides expert recommendations of different levels as academic guidance in terms of the characteristics, clinical manifestations, risk assessment, diagnosis, treatment, and prevention of chest trauma-related VTE, so as to offer a reference for clinical application.

Osteoporotic thoracolumbar fracture in the elderly will seriously reduce their quality of life and life expectancy. For osteoporotic thoracolumbar fracture in the elderly, spinal reconstruction is necessary, which should comprehensively consider factors such as the physical condition, fracture type, clinical characteristics and osteoporosis degree. While there lacks relevant clinical norms or guidelines on selection of spinal reconstruction strategies. In order to standardize the concept of spinal reconstruction for osteoporotic thoracolumbar fracture in the elderly, based on the principles of scientificity, practicality and progressiveness, the authors formulated the Clinical guideline for spinal reconstruction of osteoporotic thoracolumbar fracture in elderly patients ( version 2022), in which suggestions based on evidence of evidence-based medicine were put forward upon 10 important issues related to the fracture classification, non-operative treatment strategies and surgical treatment strategies in spinal reconstruction after osteoporosis thoracolumbar fracture in the elderly, hoping to provide a reference for clinical treatment.

Adenocarcinoma of esophagogastric junction (AEG) has attracted more attention in recent years. Surgical method of Siewert type Ⅱ AEG is especially controversial, mainly focusing on the scope of lymph node dissection, safety of surgical margin, and digestive tract reconstruction. The abdominal transhiatal approach and right thoracoabdominal Ivor-Lewis approach are the main surgical approaches of totally laparoscopic or thoracoscopic surgery for Siewert type Ⅱ AEG, which not only need close teamwork, but also require rich experience in laparoscopic surgery. The authors has started to choose these two totally minimally invasive surgical approaches, the feasibility and safety of which are proved. The key surgical details are presented in this article for reference.

Glutamic acid is an important amino acid with wide range of applications and huge market demand. Therefore, by performing transcriptome sequencing and re-sequencing analysis on Corynebacterium glutamicum E01 and high glutamate-producing strain C. glutamicum G01, we identified and selected genes with significant differences in transcription and gene levels in the central metabolic pathway that may have greatly influenced glutamate synthesis and further increased glutamic acid yield. The oxaloacetate node and α-ketoglutarate node play an important role in glutamate synthesis. The oxaloacetate node and α-ketoglutarate node were studied to explore effect on glutamate production. Based on the integrated strain constructed from the above experimental results, the growth rate in a 5-L fermenter was slightly lower than that of the original strain, but the glutamic acid yield after 48 h reached (136.1±5.53) g/L, higher than the original strain (93.53±4.52) g/L, an increase by 45.5%; sugar-acid conversion rate reached 58.9%, an increase of 13.7% compared to 45.2% of the original strain. The application of the above experimental strategy improved the glutamic acid yield and the sugar-acid conversion rate, and provided a theoretical basis for the metabolic engineering of Corynebacterium glutamicum.
Citric Acid Cycle ; Corynebacterium glutamicum/metabolism* ; Glutamic Acid/metabolism* ; Metabolic Engineering ; Metabolic Networks and Pathways/genetics*

Objective To research the clinical application value of laparoscopic bile duct exploration and the first stage suture for choledocholithiasis. Methods The clinical data of 86 patients with choledocholithiasis were analyzed retrospectively from January 2015 to January 2017 in Affiliated Suzhou Hospital of Nanjing Medical University. According to the different methods of laparoscopic bile duct exploration, they were divided into one stage suture group (observation group, 46 cases) and T tube drainage group (control group, 40 cases). Results The recovery time of gastrointestinal function, hospitalization time and hospitalization expenses in observation group were significantly better than those in control group: (22.71 ± 10.92) h vs. (35.63 ± 11.12) h, (8.4 ± 2.6) d vs. (13.5 ± 2.3) d and (12.1 ± 3.2) thousand yuan vs. (13.5 ± 4.2) thousand yuan, and there were statistical differences (P＜0.05). Conclusions Compared with T tube drainage, the first stage suture after laparoscopic common bile duct exploration has shorter hospitalization time, lower treatment cost and faster recovery. It is a safe and feasible operation method, and is worthy of popularization and application.

Intraoperative hemorrhage is the most common complication of laparoscopic radical gastrectomy,which is also the main cause of conversion to open surgery.With the popularization of laparoscopic surgery technology worldwide,how to complete high-quality surgery and effectively avoid intraoperative or postoperative complications is the goal pursued by all surgeons.Intraoperative hemorrhage in the laparoscopic radical gastrectomy is mainly divided into parenchymal hemorrhage,perigastric vascular injury-induced hemorrhage,lymph node hemorrhage and anastomotic bleeding.Compression,electrocoagulation,vascular clipping and vascular suture repair are the most common treatments for intraoperative hemorrhage.It is necessary to use above methods in clinical work.Proficiency in laparoscopic operation skills,familiarity with perigastric vascular anatomy and variation,and improved teamwork to reduce complications are the key to laparoscopic surgery for gastric cancer.Combined with literature reports,the authors summarize experience in laparoscopic surgery for gastric cancer,discuss the prevention and treatment of hemorrhagic complications during laparoscopic radical gastrectomy.

Intra-abdominal infection complicated with hypothyroidism is very common. It mostly featured decreased T3, with or without decreased T4, and without elevated thyroid stimulating hormone(TSH). This particular type of hypothyroidism was called "low T3 syndrome" or "thyroid illness syndrome", and is called "non-thyroid illness syndrome" increasingly in recent years. Its pathogenesis has not been fully understood, and probably is associated with abnormality of hypothalamic-pituitary-thyroid axis, disorder of peripheral thyroid hormone metabolism, change in thyroid hormone binding protein, regulation of triiodothyronine receptors, effect of cytokines, and lack of trace element selenium. Intra-abdominal infection complicated with hypothyroidism should be differentiated from primary hypothyroidism, which may be one cause of mental depression, insufficient anabolism, and poor tissue healing. Therefore, the changes of T3 and T4 levels should be actively monitored in patients with severe or prolonged intra-abdominal infection. Whether treatment is needed for intra-abdominal infection complicated with hypothyroidism remains controversial. T3 replacement therapy may improve prognosis. When low T3 syndrome presents as a disease-mediated hypothyroidism, we recommend the use of levothyroxine(L-T4) or liothyronine (L-T3) treatment to improve the prognosis of critical patients. Enteral nutrition can improve hypothyroidism and has good efficacy for enterocutaneous fistula patients with intra-abdominal infection.
Humans ; Hypothyroidism ; complications ; drug therapy ; Intraabdominal Infections ; complications ; diagnosis ; therapy ; Thyroxine ; therapeutic use ; Triiodothyronine ; therapeutic use

Objective To investigate the clinical efficacy of the superior pancreatic region approach guided by pancreatic capsule in laparoscopic radical gastrectomy of 438 patients.Methods The retrospective cross-sectional study was conducted.The clinicopathological data of 438 patients who underwent laparoscopic radical gastrectomy of gastric cancer in the Second Hospital of Jilin University between April 2013 and April 2017were collected.Patients were confirmed with stage T2 and above by postoperative pathological examination and then underwent adjuvant chemotherapy of XELOX regimen.Observation indicators:(1) surgical situation;(2)postoperative recovery situation;(3) postoperative pathological examination;(4) follow-up situation.Follow-up using outpatient examination and telephone interview was performed to detect the postoperative adjuvant chemotherapy,postoperative long-term complications and tumor metastasis or recurrence up to May 2017.Measurement data with normal distribution were represented as x±s.Results (1) Surgical situation:all the 438patients underwent laparoscopic radical gastrectomy of gastric cancer through the superior pancreatic region approach guided by pancreatic capsule,including 295 undergoing distal gastrectomy and 143 undergoing total gastrectomy.There were no conversion to open surgery.Operation time and volume of intraoperative blood loss were respectively (178 ±32) minutes and (39± 11)mL.There were no intraoperative complications and death in perioperative period.(2) Postoperative recovery situation:time to anal exsufflation,time for fluid diet intake and duration of hospital stay were (32±6) hours,(26±3) hours and (8.7±2.3) days,respectively.Volume of amylase drainage was (157±35) U/L at postoperative day 1,(68±25) U/L at postoperative day 2 and (43±17) U/L at postoperative day 3,respectively.No pancreatic fistula occurred postoperatively.(3) Postoperative pathological examination:results of postoperative pathological examination showed that 218,209 and 11 patients were detected in T2,T3 and T4a staging,respectively.Numbers of lymph node dissected and lymph node metastases were respectively 27.0± 6.0 and 4.2-± 2.9.Pathological typing:high-or moderate-differentiated adenocarcinoma,lowdifferentiated adenocarcinoma and undifferentiated carcinoma or signet-ring cell carcinoma were detected in 67,279 and 92 patients,respectively.(4) Follow-up situation:of 438 patients,415 were followed up for 1-48months,with a median time of 33 months of 438 patients,293 received postoperative adjuvant chemotherapy of XELOX regimen,122 received unknown adjuvant chemotherapy or refused chemotherapy.During the follow-up,there was no oecurrence of tumor-related complications,13 patients had tumor metastases or recurrence and 5patients died of tumor recurrence or metastases.Conclusion The superior pancreatic region approach guided by pancreatic capsule is safe and feasible in laparoscopic radical gastrectomy.