Hydroxyectoine, a vital compatible solute, is widely utilized in cosmetics, food, pharmaceutical industries, and biologics. However, the current microbial fermentation methods for hydroxyectoine production face challenges including insufficient precursor supply and low yields. Therefore, developing engineering microbial strains capable of efficiently synthesizing hydroxyectoine is of great significance. In this study, we first constructed a high-yield ectoine-producing strain ECT04 by multi-copy integration of the ectoine synthesis genes ectABC into the pseudogene loci of Escherichia coli MG1655(DE3), achieving an ectoine titer of 6.03 g/L. Subsequently, we employed plasmids with varying copy numbers to express ectD from Chromohalobacter salexigens to enable the conversion for hydroxyectoine production. We further investigated the effects of promoter, co-substrate ɑ-ketoglutarate, Fe²⁺ concentration, and dissolved oxygen on hydroxyectoine synthesis. Through fed-batch fermentation in a 7-L bioreactor, we significantly enhanced the hydroxyectoine production efficiency, attaining a final titer of 8.58 g/L and a productivity of 0.24 g/(L·h). This work successfully achieved the de novo synthesis of hydroxyectoine in E. coli, laying a foundation for the efficient bioproduction of this compound.
Escherichia coli/genetics* ; Fermentation ; Amino Acids, Diamino/biosynthesis* ; Bioreactors/microbiology* ; Metabolic Engineering/methods* ; Chromohalobacter/genetics* ; Plasmids/genetics*

OBJECTIVE To study the prevention and control strategies for carbapenem-resistant Acinetobacter bau-mannii(CRAB)infection through inves-tigating an outbreak of CRAB infection in an intensive care unit(ICU),and provide a scientific basis for the prevention and control of such hospital-acquired infections.METHODS Epide-miological investigations were conducted on patients with CRAB infection in the ICU of a hospital from Jul.7 to Jul.29,2023,and microbial sampling,identification and drug sensitivity testing were conducted on suspected con-taminated environments and items.Targeted prevention and control measures were taken to control the outbreak.RESULTS Within a short period,8 patients in this hospital developed CRAB hospital-acquired infection,among whom,the drug resistance profiles of CRAB isolated from the specimens of 7 patients in bed A4,A14,B18,B19,B20,B21 and B22 were consistent.Through environmental hygiene monitoring,CRAB isolated from patient clothing,isolation gowns and medical staff uniforms matched the drug resistance profiles of the seven patient iso-lates.After taking targeted measures,no new CRAB infection cases occurred in Oct.,and CRAB was no longer i-solated from the environment and medical fabrics.CONCLUSIONS The suspected outbreak of CRAB infection may be related to the inadequate management and contamination of medical fabrics.Therefore,in addition to strictly implementing the routine prevention and control measures for multidrug-resistant bacteria,it is also crucial to strengthen the standardized management of medical fabrics for the prevention and control of hospital-acquired in-fections and outbreaks.

Objective:To explore the application effects of continuous and intermittent suturing of blood vessels under microscope in the repair of limb vascular injuries.Methods:A total of 110 patients with limb vascular injuries admitted to Kaifeng 155 Hospital from Feb 2023 to May 2024 were selected as the research subjects.According to the different methods of vascular suturing,they were divided into two groups,55 patients who underwent intermittent suturing of blood vessels under microscope were selected as the control group,while 55 patients who underwent continuous suturing of blood vessels under microscope were selected as the observation group.The perioperative indicators(arterial and venous suture time,blood circulation recovery time,hospitalization time,total blood loss),blood electrolyte levels(serum potassium ion,sodium ion,and plasma carbon dioxide binding capacity),and coagulation function indicators[prothrombin time(PT),activated partial thromboplastin time(APTT),thrombin time(TT)]before surgery,2 h and 1 d after surgery,and the incidence of complications were compared between the two groups.Results:The perioperative related indicators in the observation group were better than those in the control group(P＜0.05).The serum potassium ion,sodium ion,plasma carbon dioxide binding capacity,PT,APTT and TT in the two groups at 2 h and 1 d after operation were significantly higher than those before operation(P＜0.05).And these indicators in the observation group at 2 h after surgery were significantly higher than those in the control group(P＜0.05).However,there was no statistically significant difference in the levels of these indicators between the two groups before surgery and at 1 d after surgery(P＞0.05).The incidence of complications in the observation group was significantly lower than that in the control group(P＜0.05).Conclusion:In the repair of limb vascular injuries,continuous suturing of blood vessels under microscope can effectively shorten the time of vascular suture,reduce blood loss,improve coagulation function and blood electrolyte level,promote postoperative recovery,improve limb motor function,and reduce complications.

Objective:To analyze the echocardiographic and genetic characteristics of fetuses with common arterial trunk（CAT）.Methods:A retrospective analysis was conducted on 77 480 fetal echocardiograms examined at the Maternal-Fetal Medicine center in Fetal Heart Disease of Beijing Anzhen Hospital from November 2010 to November 2024.Among them，106 fetuses were initially diagnosed with CAT，and 95 cases were ultimately confirmed（0.1%，95/77 480）. The echocardiographic and genetic features of CAT fetuses were analyzed. According to the modified Van Praagh classification，CAT was divided into types A1-A4［with ventricular septal defect（VSD）］and B1-B4（without VSD）based on the origin of the pulmonary artery branches and the presence or absence of a VSD. Additionally，CAT was categorized into isolated and complex types based on the presence of associated intracardiac or extracardiac anomalies.Results:① Among the 95 confirmed CAT fetuses，type A accounted for 90.5%（86/95），and type B accounted for 9.5%（9/95）. All 9 type B CAT fetuses exhibited no overriding of the arterial trunk ， with 8 cases showing left ventricular hypoplasia accompanied by mitral atresia or absence.② Of the 95 CAT fetuses，14 were isolated（14.7%，14/95） ， and 81 were complex（85.3%，81/95）.The main associated intracardiac anomalies included：single ventricle（22 cases），complete atrioventricular septal defect（12 cases），anomalous pulmonary venous drainage（10 cases），right aortic arch with mirror-image branching（16 cases），and persistent left superior vena cava（14 cases）. ③ Genetic testing was performed in 31 fetuses，with 18 showing positive results，primarily 22q11.21 deletion syndrome（29.0%，9/31）. Conclusions:Apart from VSD，the most common intracardiac anomaly associated with CAT fetuses is single ventricle. Type B CAT without trunk overriding is often associated with left ventricular hypoplasia and mitral atresia or absence. The most frequent genetic abnormality in CAT fetuses is 22q11.21 deletion syndrome. Prenatal echocardiography should clarify the CAT subtype and associated anomalies，and genetic testing is strongly recommended for perinatal counseling and prognostic evaluation.

Objective:To explore the application effects of continuous and intermittent suturing of blood vessels under microscope in the repair of limb vascular injuries.Methods:A total of 110 patients with limb vascular injuries admitted to Kaifeng 155 Hospital from Feb 2023 to May 2024 were selected as the research subjects.According to the different methods of vascular suturing,they were divided into two groups,55 patients who underwent intermittent suturing of blood vessels under microscope were selected as the control group,while 55 patients who underwent continuous suturing of blood vessels under microscope were selected as the observation group.The perioperative indicators(arterial and venous suture time,blood circulation recovery time,hospitalization time,total blood loss),blood electrolyte levels(serum potassium ion,sodium ion,and plasma carbon dioxide binding capacity),and coagulation function indicators[prothrombin time(PT),activated partial thromboplastin time(APTT),thrombin time(TT)]before surgery,2 h and 1 d after surgery,and the incidence of complications were compared between the two groups.Results:The perioperative related indicators in the observation group were better than those in the control group(P＜0.05).The serum potassium ion,sodium ion,plasma carbon dioxide binding capacity,PT,APTT and TT in the two groups at 2 h and 1 d after operation were significantly higher than those before operation(P＜0.05).And these indicators in the observation group at 2 h after surgery were significantly higher than those in the control group(P＜0.05).However,there was no statistically significant difference in the levels of these indicators between the two groups before surgery and at 1 d after surgery(P＞0.05).The incidence of complications in the observation group was significantly lower than that in the control group(P＜0.05).Conclusion:In the repair of limb vascular injuries,continuous suturing of blood vessels under microscope can effectively shorten the time of vascular suture,reduce blood loss,improve coagulation function and blood electrolyte level,promote postoperative recovery,improve limb motor function,and reduce complications.

OBJECTIVE To study the prevention and control strategies for carbapenem-resistant Acinetobacter bau-mannii(CRAB)infection through inves-tigating an outbreak of CRAB infection in an intensive care unit(ICU),and provide a scientific basis for the prevention and control of such hospital-acquired infections.METHODS Epide-miological investigations were conducted on patients with CRAB infection in the ICU of a hospital from Jul.7 to Jul.29,2023,and microbial sampling,identification and drug sensitivity testing were conducted on suspected con-taminated environments and items.Targeted prevention and control measures were taken to control the outbreak.RESULTS Within a short period,8 patients in this hospital developed CRAB hospital-acquired infection,among whom,the drug resistance profiles of CRAB isolated from the specimens of 7 patients in bed A4,A14,B18,B19,B20,B21 and B22 were consistent.Through environmental hygiene monitoring,CRAB isolated from patient clothing,isolation gowns and medical staff uniforms matched the drug resistance profiles of the seven patient iso-lates.After taking targeted measures,no new CRAB infection cases occurred in Oct.,and CRAB was no longer i-solated from the environment and medical fabrics.CONCLUSIONS The suspected outbreak of CRAB infection may be related to the inadequate management and contamination of medical fabrics.Therefore,in addition to strictly implementing the routine prevention and control measures for multidrug-resistant bacteria,it is also crucial to strengthen the standardized management of medical fabrics for the prevention and control of hospital-acquired in-fections and outbreaks.

Objective:To analyze the echocardiographic and genetic characteristics of fetuses with common arterial trunk（CAT）.Methods:A retrospective analysis was conducted on 77 480 fetal echocardiograms examined at the Maternal-Fetal Medicine center in Fetal Heart Disease of Beijing Anzhen Hospital from November 2010 to November 2024.Among them，106 fetuses were initially diagnosed with CAT，and 95 cases were ultimately confirmed（0.1%，95/77 480）. The echocardiographic and genetic features of CAT fetuses were analyzed. According to the modified Van Praagh classification，CAT was divided into types A1-A4［with ventricular septal defect（VSD）］and B1-B4（without VSD）based on the origin of the pulmonary artery branches and the presence or absence of a VSD. Additionally，CAT was categorized into isolated and complex types based on the presence of associated intracardiac or extracardiac anomalies.Results:① Among the 95 confirmed CAT fetuses，type A accounted for 90.5%（86/95），and type B accounted for 9.5%（9/95）. All 9 type B CAT fetuses exhibited no overriding of the arterial trunk ， with 8 cases showing left ventricular hypoplasia accompanied by mitral atresia or absence.② Of the 95 CAT fetuses，14 were isolated（14.7%，14/95） ， and 81 were complex（85.3%，81/95）.The main associated intracardiac anomalies included：single ventricle（22 cases），complete atrioventricular septal defect（12 cases），anomalous pulmonary venous drainage（10 cases），right aortic arch with mirror-image branching（16 cases），and persistent left superior vena cava（14 cases）. ③ Genetic testing was performed in 31 fetuses，with 18 showing positive results，primarily 22q11.21 deletion syndrome（29.0%，9/31）. Conclusions:Apart from VSD，the most common intracardiac anomaly associated with CAT fetuses is single ventricle. Type B CAT without trunk overriding is often associated with left ventricular hypoplasia and mitral atresia or absence. The most frequent genetic abnormality in CAT fetuses is 22q11.21 deletion syndrome. Prenatal echocardiography should clarify the CAT subtype and associated anomalies，and genetic testing is strongly recommended for perinatal counseling and prognostic evaluation.

BACKGROUND:Pulsed electromagnetic field is a non-invasive and non-radiative treatment method.Clinical use of pulsed electromagnetic fields in the treatment of orthopedic diseases has achieved certain results. OBJECTIVE:To review the current clinical application of the pulsed electromagnetic field in the treatment of orthopedic diseases,providing a scientific theoretical basis for the clinical treatment of orthopedic diseases. METHODS:The first author used a computer to search PubMed,CBM,Cochrane Library,CNKI,and WanFang Data for related studies on the pulsed electromagnetic field in the treatment of orthopedic diseases,using the keywords of"pulsed electromagnetic field,orthopedics,osteoarthritis,osteoporosis,bone healing,electromagnetic navigation"in English and Chinese.For the literature related to the same content,recent publications were selected.A total of 69 articles were selected from the search results for review. RESULTS AND CONCLUSION:Pulsed electromagnetic field has a definite curative effect on fracture healing.It can be used in the treatment of osteomyelitis by antibacterial,bactericidal,anti-inflammatory and promoting bone healing,and can inhibit osteoporosis and its progress.In addition,the treatment of early osteoarthritis,femoral head necrosis and postoperative rehabilitation of late joint replacement through various ways can become a treatment for orthopedic diseases.However,the therapeutic mechanism of the pulsed electromagnetic field for a variety of orthopedic diseases is still unclear,and most of the research is still in the primary stage.In the future,it is still necessary to obtain more reliable evidence from high-quality research and clinical trials to provide a more perfect basis for the clinical treatment of orthopedic diseases.

BACKGROUND:Nanocomposite hydrogel has great research prospects and application potential in the treatment of osteoarthritis. OBJECTIVE:To review the research progress of nanocomposite hydrogel in osteoarthritis and cartilage repair. METHODS:Databases such as CNKI and PubMed were searched.The English key words were"nanocomposite hydrogel,nanogel,osteoarthritis,cartage,physical encapsulation,electrostatic interaction,covalent crosslinking",and the Chinese key words were"nanocomposite hydrogel,nanogel,osteoarthritis,cartage,physical encapsulation,physical encapsulation,electrostatic effect,covalent cross-linking".After an initial screening of all articles based on inclusion and exclusion criteria,71 articles with high correlation were retained for review. RESULTS AND CONCLUSION:In cell or animal experiments,nanocomposite hydrogel has the effect of improving osteoarthritis.Nanocomposite hydrogel can promote cartilage repair,improve the internal environment of osteoarthritis,and achieve the therapeutic purpose of osteoarthritis by improving the mechanical environment between joints,carrying targeted drugs,and promoting the chondrogenesis of seed cells.At present,the research of nanocomposite hydrogel in osteoarthritis disease still has a huge space to play.It is expected to open up a new way for the clinical treatment of osteoarthritis by continuing to deepen the research of material preparation and actively carrying out cell and animal experiments.

Objective:To investigate the endoscopic combined serological diagnosis strategy for G1 and G2 gastric neuroendocrine neoplasms (G-NENs), and to evaluate the safety, short-term, and long-term efficacy of two endoscopic treatment procedures: endoscopic mucosal resection (EMR) and endoscopic submucosal dissection (ESD).Methods:This study retrospectively analyzed the clinical data of 100 consecutive patients with G-NENs who were hospitalized at the Cancer Hospital of the Chinese Academy of Medical Sciences from January 2011 to October 2023. These patients underwent endoscopic treatment, and propensity score matching (PSM) was used to compare clinicopathological characteristics, as well as short-term and long-term efficacy of lesions in the EMR group and ESD group before and after treatment.Results:Among the 100 patients with G-NENs, the median age was 54 years old. Before surgery, 29 cases underwent endoscopic combined serological examination, and 24 of them (82.2%) had abnormally elevated plasma chromogranin A. The combined diagnostic strategy for autoimmune atrophic gastritis (AIG) achieved a diagnostic accuracy of 100%(22/22). A total of 235 G-NEN lesions were included, with 84 in the ESD group and 151 in the EMR group. The median size of the lesions in the ESD group (5.0 mm) was significantly larger than that in the EMR group (2.0 mm, P＜0.001). Additionally, the ESD group had significantly more lesions with pathological grade G2[23.8%(20/84) vs. 1.3%(2/151), P＜0.001], infiltration depth reaching the submucosal layer [78.6%(66/84) vs. 51.0%(77/151), P＜0.001], and more T2 stage compared to the EMR group[15.5%(13/84) vs. 0.7%(1/151), P＜0.001]. After PSM, 49 pairs of lesions were successfully matched between the two groups. Following PSM, there were no significant differences in the en bloc resection rate [100.0%(49/49) vs. 100.0%(49/49)], complete resection rate [93.9%(46/49) vs. 100.0%(49/49)], and complication rate [0(0/49) vs. 4.1%(2/49)] between the two groups. During the follow-up period, no recurrence or distant metastasis was observed in any of the lesions in both groups. Conclusions:The combination of endoscopy and serology diagnostic strategy has the potential to enhance the accuracy of diagnosing G1 and G2 stage G-NENs and their background mucosa. Endoscopic resection surgery (EMR, ESD) is a proven and safe treatment approach for G1 and G2 stage G-NENs.