Subunit 5B of constitutively photomorphogenic 9 signalosome(CSN5B)is an inhibitory factor for the biosynthesis of vitamin C in the L-galactose synthesis pathway in plants.To create mutants with richer vitamin C in tomato fruits,a dual-target vector of pKSE402-SlCSN5Bwas constructed and trans-formed into the breeding parent of 1912.Based on the molecular biological assay and DNA sequencing,17 transgenic positive lines were determined,and 6 lines of them were genetically mutated at the target site of SlCSN5B,with an editing efficiency of 35.3％.Among the mutants,2 lines were homozygous mu-tants,csn5b-6 with 180 bp deletion and csn5b-8 with 3 bp deletion.The biological traits of two types of deficiency homozygotes without exogenous T-DNA insertion derived from the T1 generation were observed,and there were no significant differences in phenotypes of the plant and fruit.Through physiological tes-ting of red-ripe fruits from T,generation lines of csn5b-6,the GMPase activity and the vitamin C content significantly increased by 43％and 37.8％,respectively,the content of hydrogen peroxide significantly decreased by 25.9％,and the content of soluble solids did not obviously change,compared with the wild type.There were no significant differences in plant traits and physiological characteristics between T1 gen-eration lines of csn5b-8 and the wild type.Based on gene expression analysis and protein structure predic-tion,the results showed that the gene of SlCSN5B normally transcribed,and the loss of large peptide seg-ments of CSN5B encoded by SlCSN5B caused changes in its structure to affect functioning,which led to an increase of vitamin C content in the line of csn5b-6-1 1.The findings suggest that the vitamin C content of tomato fruit can be improved by CRISPR/Cas9-mediated SlCSN5B gene editing,which provides the valuable resources for high-quality breeding in tomato.

Subunit 5B of constitutively photomorphogenic 9 signalosome(CSN5B)is an inhibitory factor for the biosynthesis of vitamin C in the L-galactose synthesis pathway in plants.To create mutants with richer vitamin C in tomato fruits,a dual-target vector of pKSE402-SlCSN5Bwas constructed and trans-formed into the breeding parent of 1912.Based on the molecular biological assay and DNA sequencing,17 transgenic positive lines were determined,and 6 lines of them were genetically mutated at the target site of SlCSN5B,with an editing efficiency of 35.3％.Among the mutants,2 lines were homozygous mu-tants,csn5b-6 with 180 bp deletion and csn5b-8 with 3 bp deletion.The biological traits of two types of deficiency homozygotes without exogenous T-DNA insertion derived from the T1 generation were observed,and there were no significant differences in phenotypes of the plant and fruit.Through physiological tes-ting of red-ripe fruits from T,generation lines of csn5b-6,the GMPase activity and the vitamin C content significantly increased by 43％and 37.8％,respectively,the content of hydrogen peroxide significantly decreased by 25.9％,and the content of soluble solids did not obviously change,compared with the wild type.There were no significant differences in plant traits and physiological characteristics between T1 gen-eration lines of csn5b-8 and the wild type.Based on gene expression analysis and protein structure predic-tion,the results showed that the gene of SlCSN5B normally transcribed,and the loss of large peptide seg-ments of CSN5B encoded by SlCSN5B caused changes in its structure to affect functioning,which led to an increase of vitamin C content in the line of csn5b-6-1 1.The findings suggest that the vitamin C content of tomato fruit can be improved by CRISPR/Cas9-mediated SlCSN5B gene editing,which provides the valuable resources for high-quality breeding in tomato.

Objective To investigate the toxicokinetic differences of 3,4-methylenedioxy-N-methylamphetamine(MDMA)and its metabolite 4,5-methylene dioxy amphetamine(MDA)in rats af-ter single and continuous administration of MDMA,providing reference data for the forensic identifica-tion of MDMA.Methods A total of 24 rats in the single administration group were randomly divided into 5,10 and 20 mg/kg experimental groups and the control group,with 6 rats in each group.The ex-perimental group was given intraperitoneal injection of MDMA,and the control group was given intraperi-toneal injection of the same volume of normal saline as the experimental group.The amount of 0.5 mL blood was collected from the medial canthus 5 min,30 min,1 h,1.5 h,2 h,4 h,6 h,8 h,10 h,12 h after administration.In the continuous administration group,24 rats were randomly divided into the experi-mental group(18 rats)and the control group(6 rats).The experimental group was given MDMA 7 d by continuous intraperitoneal injection in increments of 5,7,9,11,13,15,17 mg/kg per day,respectively,while the control group was given the same volume of normal saline as the experimental group by in-traperitoneal injection.On the eighth day,the experimental rats were randomly divided into 5,10 and 20 mg/kg dose groups,with 6 rats in each group.MDMA was injected intraperitoneally,and the con-trol group was injected intraperitoneally with the same volume of normal saline as the experimental group.On the eighth day,0.5 mL of blood was taken from the medial canthus 5 min,30 min,1 h,1.5 h,2 h,4 h,6 h,8 h,10 h,12 h after administration.Liquid chromatography-triple quadrupole tandem mass spectrometry was used to detect MDMA and MDA levels,and statistical software was employed for data analysis.Results In the single-administration group,peak concentrations of MDMA and MDA were reached at 5 min and 1 h after administration,respectively,with the largest detection time limit of 12 h.In the continuous administration group,peak concentrations were reached at 30 min and 1.5 h af-ter administration,respectively,with the largest detection time limit of 10 h.Nonlinear fitting equations for the concentration ratio of MDMA and MDA in plasma and administration time in the single-administration group and continuous administration group were as follows:T=10.362C-1.183,R2=0.974 6;T=7.397 3C-0.694,R2=0.961 5(T:injection time;C:concentration ratio of MDMA to MDA in plasma).Conclusions The toxicokinetic data of MDMA and its metabolite MDA in rats,obtained through single and continuous administration,including peak concentration,peak time,detection time limit,and the relationship between concentration ratio and administration time,provide a theoretical and data foundation for relevant forensic identification.

Objective To evaluate the perioperative safety of lung surgery for patients with corona virus disease 2019 (COVID-19). Methods We retrospectively analyzed the clinical data of the patients recovered from COVID-19 infection and received lung surgery from December 2022 to February 2023 in the Department of Thoracic Surgery at Beijing Hospital. Patients who received lung surgery and without COVID-19 at the same time were selected as a control group. Perioperative data between the two groups were compared. Results A total of 103 patients were included with 44 males and 49 females at an average age of (62.2±12.1) years. All surgeries were performed by uniportal video-assisted thoracoscopic surgery (VATS). Among patients who recovered from COVID-19, 53 (51.5%) received lobectomy, 30 (29.1%) received segmentectomy, and 20 (19.4%) received wedge resection. The interval between diagnosis of infection and lung surgery was ≤1 month in 32 (31.1%) patients, and >1 month in 71 (68.9%) patients. The results of virus nucleic acid test for all patients before surgery were negative. A total of 13 (12.6%) patients had positive IgM, and 100 (97.1%) patients had positive IgG. A total of 20 patients experienced perioperative complications (13 patients with pulmonary air leakage, 3 patients with chylothorax, 2 patients with atrial fibrillation, and 2 patients with severe pulmonary complications). There was one perioperative death. Comparing the patients who recovered from COVID-19 with those without COVID-19, we found no statistical difference in perioperative outcomes including surgical duration, postoperative drainage, duration of thoracic tube, and duration of postoperative stay (P>0.05). There was no significant difference in perioperative complications between the two groups (P>0.05). Multivariable logistical regression analysis demonstrated that positive IgM before surgery (OR=7.319, 95%CI 1.669 to 32.103, P=0.008), and longer duration of surgery (OR=1.016, 95%CI 1.003 to 1.028, P=0.013) were independent risk factors of perioperative complications for patients who recovered from COVID-19. Conclusion It is safe for patients recover from COVID-19 to receive lung surgery when symptoms disappear and the nucleic acid test turn negative. However, positive COVID-19 IgM is an independent risk factor for perioperative complications. We suggest that lung surgery could be performed when the nucleic acid test and COVID-19 IgM are both negative for patients recover from COVID-19 infection.

Objective:To explore the clinical effect of composite skin transplantation combined with systemic rehabilitation in the treatment of extensive scar contracture deformity around the popliteal fossa in children after burns.Methods:A retrospective observational research method was adopted. Seventeen children with extensive scar contracture deformities around the popliteal fossa after burns who met the inclusion criteria and were admitted to the First Affiliated Hospital of Air Force Military Medical University from March 2018 to April 2022 were selected. Among them, there were 10 males and 7 females, aged 2-11 years, with scar contracture deformities lasting from 10 months to 9 years, all located around the popliteal fossa, 10 cases of right popliteal fossa, 5 cases of left popliteal fossa, 2 cases of bilateral popliteal fossa, scars around the popliteal fossa result in a knee joint extension angle of only 95° to 115°. The scar contracture during surgery was thoroughly released, joint mobility was restored, so as to form a secondary wound range of 10 cm×8 cm-20 cm×13 cm. In stage Ⅰ, after completely releasing the scar contracture, the wound was covered with negative pressure closure drainage (VSD) for 2-3 days. In stage Ⅱ, a large autologous blade thick scalp and allogeneic decellularized dermal matrix composite graft was performed to repair the wound around the popliteal fossa. After 8-10 days of surgery, the dressing was changed to check the survival of the skin graft. One week after the skin graft survived, a 12 month orderly knee joint function training was conducted under the guidance of a rehabilitation therapist. Postoperative sequential treatment with a combination of strong pulsed light and ultra pulsed carbon dioxide lattice laser for 5-7 courses of significant scar hyperplasia in the skin graft area and edges.Results:15 cases of pediatric patients had good skin graft survival; One patient developed a wound due to partial displacement of the transplanted autologous scalp, and one patient developed a plasma swelling under the limb graft, which was drained through an opening. Two patients underwent dressing changes for 3 weeks before the wound healed. After follow-up for 6 to 36 months, the elasticity and appearance of the skin graft were similar to those of a medium thickness skin graft. Children with knee joint contracture were able to fully extend to 180°, and knee joint function was significantly improved. There was no scar formation or hair loss in the donor skin area.Conclusions:The combination of composite skin transplantation and systematic rehabilitation has a good effect on the treatment of extensive scar contracture around the popliteal fossa in children after burns, avoiding the problem of scars left in the donor area due to autologous skin grafting.

Objective:To investigate the clinical application value of commonly used preoperative indicators of sarcopenia in predicting postoperative pneumonia in patients aged 70 years and above with esophageal cancer.Methods:A retrospective analysis was conducted on the clinical data of 398 elderly patients(≥70 years old)with esophageal squamous cell carcinoma who underwent thoracic laparoscopic radical resection of esophageal cancer in our hospital from January 2020 to December 2021.The study aimed to investigate the correlation between clinical pathological indicators and commonly used measurement indicators of sarcopenia and postoperative pneumonia.Statistical analysis was performed to analyze the data.Results:The study found that the proportion of postoperative pneumonia in esophageal squamous cell carcinoma patients aged 70 years and above was 27.9%(111 out of 398). The pneumonia group had significantly lower preoperative BMI and peak expiratory flow(PEF)measurements compared to the non-pneumonia group, with statistically significant differences( t=2.799, 2.674, both P<0.05). Logistic multivariate analysis revealed that low PEF, low psoas major muscle index(PMI), and low psoas muscle density(PMD)were the primary risk factors for postoperative pneumonia in esophageal cancer patients aged 70 years and above(Wald χ2 values were 7.577, 6.091, 6.845, all P<0.05). The risk of postoperative pneumonia in esophageal cancer patients aged 70 years and above with low PEF, low PMI, and low PMD was found to be 1.969 times higher(95% CI: 1.215-3.185, P=0.006), 1.912 times higher(95% CI: 1.143-3.205, P=0.014), and 1.832 times higher(95% CI: 1.164-2.882, P=0.009)respectively, compared to patients with high PEF, high PMI, and high PMD. Conclusions:Low PEF, low PMI, and low PMD are significant risk factors for postoperative pneumonia in esophageal cancer patients aged 70 years and older.Preoperative PEF, PMI, and PMD, which are commonly utilized measurement indicators for sarcopenia, can be utilized as early screening indicators for postoperative pneumonia.

Manganese superoxide dismutase catalyzes the dismutation of two molecules of superoxide radicals to one molecule of oxygen and one molecule of hydrogen peroxide. The oxidation of superoxide anion to oxygen by Mn³⁺SOD proceeds at a rate close to diffusion. The reduction of superoxide anion to hydrogen peroxide by Mn²⁺SOD can be progressed parallelly in either a fast or a slow cycle pathway. In the slow cycle pathway, Mn²⁺SOD forms a product inhibitory complex with superoxide anion, which is protonated and then slowly releases hydrogen peroxide out. In the fast cycle pathway, superoxide anion is directly converted into product hydrogen peroxide by Mn²⁺SOD, which facilitates the revival and turnover of the enzyme. We proposed for the first time that temperature is a key factor that regulates MnSOD into the slow- or fast-cycle catalytic pathway. Normally, the Mn²⁺ rest in the pent-coordinated state with four amino acid residues (His26, His74, His163 and Asp159) and one water (WAT1) in the active center of MnSOD. The sixth coordinate position on Mn (orange arrow) is open for water (WAT2, green) or O₂^• to coordinate. With the cold contraction in the active site as temperature decreases, WAT2 is closer to Mn, which may spatially interfere with the entrance of O₂^• into the inner sphere, and avoid O₂^•/Mn²⁺ coordination to reduce product inhibition. Low temperature compels the reaction into the faster outer sphere pathway, resulting in a higher gating ratio for the fast-cycle pathway. As the temperature increases in the physiological temperature range, the slow cycle becomes the mainstream of the whole catalytic reaction, so the increasing temperature in the physiological range inhibits the activity of the enzyme. The biphasic enzymatic kinetic properties of manganese superoxide dismutase can be rationalized by a temperature-dependent coordination model of the conserved active center of the enzyme. When the temperature decreases, a water molecule (or OH^-) is close to or even coordinates Mn, which can interfere with the formation of product inhibition. So, the enzymatic reaction occurs mainly in the fast cycle pathway at a lower temperature. Finally, we describe the several chemical modifications of the enzyme, indicating that manganese superoxide dismutase can be rapidly regulated in many patterns (allosteric regulation and chemical modification). These regulatory modulations can rapidly and directly change the activation of the enzyme, and then regulate the balance and fluxes of superoxide anion and hydrogen peroxide in cells. We try to provide a new theory to reveal the physiological role of manganese superoxide dismutase and reactive oxygen species.

Objective To monitor the susceptibility of clinical isolates to antimicrobial agents in healthcare facilities in major regions of China in 2023.Methods Clinical isolates collected from 73 hospitals across China were tested for antimicrobial susceptibility using a unified protocol based on disc diffusion method or automated testing systems.Results were interpreted using the 2023 Clinical & Laboratory Standards Institute (CLSI) breakpoints.Results A total of 445199 clinical isolates were collected in 2023,of which 29.0％ were gram-positive and 71.0％ were gram-negative.The prevalence of methicillin-resistant strains in Staphylococcus aureus,Staphylococcus epidermidis and other coagulase-negative Staphylococcus species (excluding Staphylococcus pseudintermedius and Staphylococcus schleiferi) (MRSA,MRSE and MRCNS) was 29.6％,81.9％ and 78.5％,respectively.Methicillin-resistant strains showed significantly higher resistance rates to most antimicrobial agents than methicillin-susceptible strains (MSSA,MSSE and MSCNS).Overall,92.9％ of MRSA strains were susceptible to trimethoprim-sulfamethoxazole and 91.4％ of MRSE strains were susceptible to rifampicin.No vancomycin-resistant strains were found.Enterococcus faecalis had significantly lower resistance rates to most antimicrobial agents tested than Enterococcus faecium.A few vancomycin-resistant strains were identified in both E.faecalis and E.faecium.The prevalence of penicillin-susceptible Streptococcus pneumoniae was 93.1％ in the isolates from children and and 95.9％ in the isolates from adults.The resistance rate to carbapenems was lower than 15.0％ for most Enterobacterales species except for Klebsiella,22.5％ and 23.6％ of which were resistant to imipenem and meropenem,respectively .Most Enterobacterales isolates were highly susceptible to tigecycline,colistin and polymyxin B,with resistance rates ranging from 0.6％ to 10.0％.The resistance rate to imipenem and meropenem was 21.9％ and 17.4％ for Pseudomonas aeruginosa,respectively,and 67.5％ and 68.1％ for Acinetobacter baumannii,respectively.Conclusions Increasing resistance to the commonly used antimicrobial agents is still observed in clinical bacterial isolates.However,the prevalence of important crabapenem-resistant organisms such as crabapenem-resistant K.pneumoniae,P.aeruginosa,and A.baumannii showed a slightly decreasing trend.This finding suggests that strengthening bacterial resistance surveillance and multidisciplinary linkage are important for preventing the occurrence and development of bacterial resistance.

Objective To investigate the application of pre-hemostatic suturing in adolescent circumcision with a stapler.Methods A total of 120 patients with long foreskin treated in our hospital were included,and they were divided into two groups by random number table method,among which the patients in the observation group received circumcision with a stapler after pre-hemostatic suturing of the foreskin vessels,and these in the control group received conventional circumcision with a stapler.The operation time,intraoperative blood loss,postoperative healing time and occurrence of postoperative hematoma of the two groups were analyzed.Results There was no significant difference in the operation time between the two groups(P＞0.05).The intraoperative blood loss in the observation group was less than that in the control group,the postoperative healing time was shorter than that in the control group,and the incidence of postoperative hematoma was lower than that in the control group,with statistically significant differences(P＜0.05).Conclusion The application of pre-hemostatic suturing in circumcision with a stapler can improve surgical safety,with ease of learning,which may increase the benefit of patients.

Objective To monitor the susceptibility of clinical isolates to antimicrobial agents in tertiary hospitals in major regions of China in 2022.Methods Clinical isolates from 58 hospitals in China were tested for antimicrobial susceptibility using a unified protocol based on disc diffusion method or automated testing systems.Results were interpreted using the 2022 Clinical &Laboratory Standards Institute(CLSI)breakpoints.Results A total of 318 013 clinical isolates were collected from January 1,2022 to December 31,2022,of which 29.5％were gram-positive and 70.5％were gram-negative.The prevalence of methicillin-resistant strains in Staphylococcus aureus,Staphylococcus epidermidis and other coagulase-negative Staphylococcus species(excluding Staphylococcus pseudintermedius and Staphylococcus schleiferi)was 28.3％,76.7％and 77.9％,respectively.Overall,94.0％of MRSA strains were susceptible to trimethoprim-sulfamethoxazole and 90.8％of MRSE strains were susceptible to rifampicin.No vancomycin-resistant strains were found.Enterococcus faecalis showed significantly lower resistance rates to most antimicrobial agents tested than Enterococcus faecium.A few vancomycin-resistant strains were identified in both E.faecalis and E.faecium.The prevalence of penicillin-susceptible Streptococcus pneumoniae was 94.2％in the isolates from children and 95.7％in the isolates from adults.The resistance rate to carbapenems was lower than 13.1％in most Enterobacterales species except for Klebsiella,21.7％-23.1％of which were resistant to carbapenems.Most Enterobacterales isolates were highly susceptible to tigecycline,colistin and polymyxin B,with resistance rates ranging from 0.1％to 13.3％.The prevalence of meropenem-resistant strains decreased from 23.5％in 2019 to 18.0％in 2022 in Pseudomonas aeruginosa,and decreased from 79.0％in 2019 to 72.5％in 2022 in Acinetobacter baumannii.Conclusions The resistance of clinical isolates to the commonly used antimicrobial agents is still increasing in tertiary hospitals.However,the prevalence of important carbapenem-resistant organisms such as carbapenem-resistant K.pneumoniae,P.aeruginosa,and A.baumannii showed a downward trend in recent years.This finding suggests that the strategy of combining antimicrobial resistance surveillance with multidisciplinary concerted action works well in curbing the spread of resistant bacteria.