Objective To explore the efficacy of bilateral facial muscle training combined with visual electromyography biofeedback on facial nerve function recovery in patients with idiopathic facial nerve palsy. Methods Patients with idiopathic facial nerve palsy admitted to Shanghai Fifth People’s Hospital, Fudan University from July 2022 to July 2024 were selected and randomly divided into a control group and an intervention group. The control group received conventional physical factor therapy, while the intervention group received bilateral facial muscle training combined with visual electromyography biofeedback therapy based on the control group’s regimen. After 20 treatment sessions, the total effective rate, the House-Brackmann (H-B) facial nerve grading system, the Sunnybrook Facial Grading System (SFGS) score, and the average value ratio of maximal amplitudes of bilateral frontalis and zygomaticus muscles were compared between the two groups. Results A total of 90 patients were included, 45 in each group. After 20 treatment sessions, the total effective rate was significantly higher in the intervention group than in the control group (84.4% vs 75.6%, P＝0.003). Compared with the control group, the intervention group demonstrated a significantly lower H-B grade (P＝0.003) and a higher SFGS score (P＝0.001). The average value ratios of maximal amplitudes of the affected versus healthy side frontalis (P＝0.013) and zygomatic (P＝0.022) muscles were higher in the intervention group than in the control group. Conclusions Bilateral facial muscle training combined with visual electromyography biofeedback is an effective approach for treating idiopathic facial nerve palsy, effectively promoting the recovery of facial nerve function, and improving facial symmetry and facial muscle function.

OBJECTIVE To understand the epidemiological characteristics and change of drug resistance of Klebsiel-la pneumoniae strains from a hospital so as to adjust the use of antibiotics and control the transmission of hospital-associated infection caused by the K.pneumoniae.METHODS The K.pneumoniae strains were isolated from the patients who were hospitalized in The 305 Hospital of PLA from 2018 to 2022.The data of drug susceptibility tes-ting were exported by using WHONET 5.6,the clinical data and changing trend of drug resistance were retro-spectively analyzed with the use of SPSS 25.0 software.RESULTS Totally 9157 strains of bacteria were isolated from the patients who were hospitalized from 2018 to 2022,1502(16.40％)of which were K.pneumoniae,and the isolation rate showed a downward trend(x2=15.054,P＜0.001).Sputum(77.16％)was the major type of specimen;the strains were mainly isolated from intensive care unit(55.26％).The patients aged more than 79 years old were dominant,accounting for 65.58％.The result of drug susceptibility testing showed that there were significant differences in the drug resistance rates to the commonly used antibiotics from 2018 to 2022(P＜0.05).The drug resistance rates to aztreonam,ertapenem and tigecycline showed upward trends with the years(P＜0.05),while the drug resistance rates to the rest of drugs such as cefoperazone-sulbactam,ceftazidime and amika-cin showed downward trends(P＜0.05).CONCLUSIONS There is significant difference in the clinical distribution of the K.pneumoniae strains in recent 5 years.The key populations and departments should be attached great im-portance to.The drug resistance rates of the K.pneumoniae strains to many types of antibiotics show downward trends,but the situation of drug resistance is still serious.It is necessary to continue to implement the prevention and control policies for drug resistance and reasonably use antibiotics based on the result of drug susceptibility testing.

OBJECTIVE To understand the epidemiological characteristics and change of drug resistance of Klebsiel-la pneumoniae strains from a hospital so as to adjust the use of antibiotics and control the transmission of hospital-associated infection caused by the K.pneumoniae.METHODS The K.pneumoniae strains were isolated from the patients who were hospitalized in The 305 Hospital of PLA from 2018 to 2022.The data of drug susceptibility tes-ting were exported by using WHONET 5.6,the clinical data and changing trend of drug resistance were retro-spectively analyzed with the use of SPSS 25.0 software.RESULTS Totally 9157 strains of bacteria were isolated from the patients who were hospitalized from 2018 to 2022,1502(16.40％)of which were K.pneumoniae,and the isolation rate showed a downward trend(x2=15.054,P＜0.001).Sputum(77.16％)was the major type of specimen;the strains were mainly isolated from intensive care unit(55.26％).The patients aged more than 79 years old were dominant,accounting for 65.58％.The result of drug susceptibility testing showed that there were significant differences in the drug resistance rates to the commonly used antibiotics from 2018 to 2022(P＜0.05).The drug resistance rates to aztreonam,ertapenem and tigecycline showed upward trends with the years(P＜0.05),while the drug resistance rates to the rest of drugs such as cefoperazone-sulbactam,ceftazidime and amika-cin showed downward trends(P＜0.05).CONCLUSIONS There is significant difference in the clinical distribution of the K.pneumoniae strains in recent 5 years.The key populations and departments should be attached great im-portance to.The drug resistance rates of the K.pneumoniae strains to many types of antibiotics show downward trends,but the situation of drug resistance is still serious.It is necessary to continue to implement the prevention and control policies for drug resistance and reasonably use antibiotics based on the result of drug susceptibility testing.

Objective:To develop a deep learning-based system for real-time recognition and classification of portal hypertensive gastropathy (PHG) and evaluate its ability to assist junior endoscopists.Methods:A total of 2 848 gastroscopy images from 832 patients with liver cirrhosis were selected from Digestive Endoscopy Center databases of Renmin Hospital of Wuhan University, Wuhan Hospital of Traditional Chinese and Western Medicine, and the Second Hospital of Jingzhou from January 2015 to October 2023. This system referred to 3 endoscopic features of Baveno Ⅱ scoring system. Three models were developed respectively for gastric antral vascular ectasia (GAVE), mosaic-like pattern (MLP), and red marks (RM). The specific classification references were as follows: (1) GAVE model: 0 no, 1 yes; (2) MLP model: 0 no, 1 mild, 2 severe; (3) RM model: 0 no, 1 isolated, 2 fused. The classification results for endoscopic characteristics of PHG of 3 endoscopy experts were taken as the gold standard. The yolov8-m model was used for training. The training dataset, validation dataset, and test dataset were allocated at a ratio of 8∶1∶1. The test dataset was used to evaluate the performance of models and their auxiliary effects on endoscopists. The accuracy, recall, precision, specificity and Kappa coefficient were calculated. Results:The accuracy, recall, specificity of GAVE model were 96.0% (48/50), 87.5% (7/8) and 97.6% (41/42). There was no significant difference between its accuracy and the gold standard ( χ2=316.226, P=1.000). The precision of GAVE1 and GAVE0 were 87.5% (7/8) and 97.6% (41/42) respectively. The accuracy of MLP model was 84.1% (132/157), and there was no significant difference compared with the gold standard ( χ2=3.286, P=0.193). The precision and recall of MLP2 were 88.2% (15/17) and 75.0% (15/20). The precision and recall of MLP1 were 77.9% (60/77) and 88.2% (60/68). The precision and recall of MLP0 were 90.5% (57/63) and 82.6% (57/69). The accuracy of RM model was 87.9% (123/140), and there was no significant difference compared with the gold standard ( χ2=2.891, P=0.409). The precision and recall of RM2 were 94.7% (18/19) and 78.3% (18/23). The precision and recall of RM1 were 72.2% (26/36) and 81.3% (26/32). The precision and recall of RM0 were 92.9% (79/85) and 92.9% (79/85). The mean accuracy of the three junior endoscopists, with and without the assistance of the GAVE model, MLP model, and RM model, respectively increased from 95.3% to 99.3%, from 83.9% to 91.9%, and from 81.9% to 83.1%. The overall consistency analysis of the 3 junior endoscopists with the gold standard indicated that the consistency of the GAVE model before and after assistance was extremely strong (both an overall Kappa of 1.000); the consistency before assistance of the MLP model was moderate (with an overall Kappa of 0.601), which increased to extremely strong after assistance (with an overall Kappa of 0.964); and the consistency of the RM model before and after assistance was also relatively strong (with an overall Kappa of 0.792 before and 0.798 after). Conclusion:The deep learning system accurately identifies and classifies PHG features and significantly enhances diagnostic performance of junior endoscopists.

Objective:To develop a deep learning-based system for real-time recognition and classification of portal hypertensive gastropathy (PHG) and evaluate its ability to assist junior endoscopists.Methods:A total of 2 848 gastroscopy images from 832 patients with liver cirrhosis were selected from Digestive Endoscopy Center databases of Renmin Hospital of Wuhan University, Wuhan Hospital of Traditional Chinese and Western Medicine, and the Second Hospital of Jingzhou from January 2015 to October 2023. This system referred to 3 endoscopic features of Baveno Ⅱ scoring system. Three models were developed respectively for gastric antral vascular ectasia (GAVE), mosaic-like pattern (MLP), and red marks (RM). The specific classification references were as follows: (1) GAVE model: 0 no, 1 yes; (2) MLP model: 0 no, 1 mild, 2 severe; (3) RM model: 0 no, 1 isolated, 2 fused. The classification results for endoscopic characteristics of PHG of 3 endoscopy experts were taken as the gold standard. The yolov8-m model was used for training. The training dataset, validation dataset, and test dataset were allocated at a ratio of 8∶1∶1. The test dataset was used to evaluate the performance of models and their auxiliary effects on endoscopists. The accuracy, recall, precision, specificity and Kappa coefficient were calculated. Results:The accuracy, recall, specificity of GAVE model were 96.0% (48/50), 87.5% (7/8) and 97.6% (41/42). There was no significant difference between its accuracy and the gold standard ( χ2=316.226, P=1.000). The precision of GAVE1 and GAVE0 were 87.5% (7/8) and 97.6% (41/42) respectively. The accuracy of MLP model was 84.1% (132/157), and there was no significant difference compared with the gold standard ( χ2=3.286, P=0.193). The precision and recall of MLP2 were 88.2% (15/17) and 75.0% (15/20). The precision and recall of MLP1 were 77.9% (60/77) and 88.2% (60/68). The precision and recall of MLP0 were 90.5% (57/63) and 82.6% (57/69). The accuracy of RM model was 87.9% (123/140), and there was no significant difference compared with the gold standard ( χ2=2.891, P=0.409). The precision and recall of RM2 were 94.7% (18/19) and 78.3% (18/23). The precision and recall of RM1 were 72.2% (26/36) and 81.3% (26/32). The precision and recall of RM0 were 92.9% (79/85) and 92.9% (79/85). The mean accuracy of the three junior endoscopists, with and without the assistance of the GAVE model, MLP model, and RM model, respectively increased from 95.3% to 99.3%, from 83.9% to 91.9%, and from 81.9% to 83.1%. The overall consistency analysis of the 3 junior endoscopists with the gold standard indicated that the consistency of the GAVE model before and after assistance was extremely strong (both an overall Kappa of 1.000); the consistency before assistance of the MLP model was moderate (with an overall Kappa of 0.601), which increased to extremely strong after assistance (with an overall Kappa of 0.964); and the consistency of the RM model before and after assistance was also relatively strong (with an overall Kappa of 0.792 before and 0.798 after). Conclusion:The deep learning system accurately identifies and classifies PHG features and significantly enhances diagnostic performance of junior endoscopists.

Objective:To describe the current status and trends in the outcomes and care practices of extremely preterm infants at 22-25 weeks′ gestation age from the Chinese Neonatal Network (CHNN) from 2019 to 2021.Methods:This cross-sectional study used data from the CHNN cohort of very preterm infants. All 963 extremely preterm infants with gestational age between 22-25 weeks who were admitted to neonatal intensive care units (NICU) of the CHNN from 2019 to 2021 were included. Infants admitted after 24 hours of life or transferred to non-CHNN hospitals were excluded. Perinatal care practices, survival rates, incidences of major morbidities, and NICU treatments were described according to different gestational age groups and admission years. Comparison among gestational age groups was conducted using χ2 and Kruskal-Wallis tests. Trends by year were evaluated by Cochran-Armitage and Jonckheere-Terpstra tests for trend. Results:Of the 963 extremely preterm infants enrolled, 588 extremely preterm infants (61.1%) were male. The gestational age was 25.0 (24.4, 25.6) weeks, with 29 extremely preterm infants (3.0%), 88 extremely preterm infants (9.1%), 264 extremely preterm infants (27.4%), and 582 extremely preterm infants (60.4%) at 22, 23, 24, and 25 weeks of gestation age, respectively. The birth weight was 770 (680, 840) g. From 2019 to 2021, the number of extremely preterm infants increased each year (285, 312, and 366 extremely preterm infants, respectively). Antenatal steroids and magnesium sulfate were administered to 67.7% (615/908) and 51.1% (453/886) mothers of extremely preterm infants. In the delivery room, 20.8% (200/963) and 69.5% (669/963) extremely preterm infants received noninvasive positive end-expiratory pressure support and endotracheal intubation. Delayed cord clamping and cord milking were performed in 19.0% (149/784) and 30.4% (241/794) extremely preterm infants. From 2019 to 2021, there were significant increases in the usage of antenatal steroids, antenatal magnesium sulfate, and delivery room noninvasive positive-end expiratory pressure support (all P<0.05). Overall, 349 extremely preterm infants (36.2%) did not receive complete care, 392 extremely preterm infants (40.7%) received complete care and survived to discharge, and 222 extremely preterm infants (23.1%) received complete care but died in hospital. The survival rates for extremely preterm infants at 22, 23, 24 and 25 weeks of gestation age were 10.3% (3/29), 23.9% (21/88), 33.0% (87/264) and 48.3% (281/582), respectively. From 2019 to 2021, there were no statistically significant trends in complete care, survival, and mortality rates (all P>0.05). Only 11.5% (45/392) extremely preterm infants survived without major morbidities. Moderate to severe bronchopulmonary dysplasia (67.3% (264/392)) and severe retinopathy of prematurity (61.5% (241/392)) were the most common morbidities among survivors. The incidences of severe intraventricular hemorrhage or periventricular leukomalacia, necrotizing enterocolitis, and sepsis were 15.3% (60/392), 5.9% (23/392) and 19.1% (75/392), respectively. Overall, 83.7% (328/392) survivors received invasive ventilation during hospitalization, with a duration of 22 (10, 42) days. The hospital stay for survivors was 97 (86, 116) days. Conclusions:With the increasing number of extremely preterm infants at 22-25 weeks′ gestation admitted to CHNN NICU, the survival rate remained low, especially the rate of survival without major morbidities. Further quality improvement initiatives are needed to facilitate the implementation of evidence-based care practices.

Precision treatment of cancer has entered the era of immunotherapy represented by immune checkpoint inhibitors(ICIs).Tumor tissue-based detection,such as programmed cell death-ligand 1 and tumor mutational burden are common biomarkers used in clinical screening for the benefit groups of ICIs.However,the wide application of tissue-based detection has been limited for insufficient tumor tissue samples and the need for invasive and complex operation.The recent rise of peripheral blood biomarkers pro-vides an alternative non-invasive solution to address these defects.This review summarizes the research progress of peripheral blood biomarkers related to immune checkpoint inhibitors,in order to provide references in clinic for screening groups benefiting from ICIs.

Objective:To investigate the current status, trends, and differences among institutions in the application of delivery room continuous positive airway pressure (DRCPAP) for very preterm infants treated in the institutions in the Chinese Neonatal Network (CHNN). Also, to explore the impact of DRCPAP on the outcomes of very preterm infants in China.Methods:A retrospective cohort study was conducted. Based on the CHNN very preterm infant cohort, very preterm infants (gestational ages ranging from 25 weeks +0 to 31 weeks +6) born in-hospital and treated in 79 tertiary neonatal intensive care units (NICUs) participating in the CHNN from 2019 to 2021 were included. The usage rates of DRCPAP in different hospitals, as well as gestational ages and years, were described. Data were analyzed using the Chi-square test (or Fisher's exact test) or t-test. A multivariate logistic regression model was established to explore the correlation between DRCPAP and clinical outcomes. Results:(1) A total of 18 048 very preterm infants were included. Among them, 3 666 (20.3%) received DRCPAP, and 14 382 (79.7%) did not. (2) The usage rate of DRCPAP for very preterm infants among different institutions is from 0.0% to 94.5%. Fourteen institutions did not use DRCPAP, and 55 institutions had a usage rate below 30%. The usage rate of DRCPAP in very preterm infants increased annually, from 13.8% (818/5 916) in 2019 to 26.0% (1 583/6 097) in 2021 ( χ2trend=122.00, P<0.001). (3) The DRCPAP group had higher rates of maternal assisted reproductive technology pregnancy, chorioamnionitis, a full course of antenatal corticosteroids, gestational diabetes, fetal distress, antenatal magnesium sulfate use, and cesarean delivery compared to the non-DRCPAP group [20.3% (744/3 665) vs. 17.6% (2 529/14 369), χ2=14.45; 23.0% (695/3 021) vs. 16.4% (1 956/11 926), χ2=72.57; 57.1% (2 090/3 660) vs. 54.3% (7 766/14 302), χ2=9.55; 23.0% (844/3 669) vs. 20.7% (2 969/14 342), χ2=9.77; 8.7% (319/3 666) vs. 7.0% (1 006/14 371), χ2=12.51; 87.1% (3 186/3 657) vs. 82.0% (11 736/14 312), χ2=81.38; 63.5% (2 327/3 664) vs. 60.7% (8 722/14 369), χ2=9.59; all P<0.05]. While the incidence of hypertensive disorders of pregnancy and the proportion of infants not using antenatal corticosteroids were lower in the non-DRCPAP group [17.1% (626/3 660) vs. 22.6% (3 183/14 084), χ2=44.70; 14.2% (520/3 661) vs. 19.7% (2 814/14 284), χ2=57.34; all P<0.05]. The DRCPAP group had lower birth weight and gestational age, higher 1 min and 5 min Apgar scores, and lower neonatal transport stabilization index scores [(1 308±314) g vs. (1 325±315) g, t=2.90; (29.5±1.7) weeks vs. (29.7±1.6) weeks, t=3.96; (7.9±1.8) scores vs. (7.6±1.9) scores, t=－9.80; (9.0±1.1) scores vs. (8.7±1.3) scores, t=－13.01; (11.0±9.4) scores vs. (13.1±9.8) scores, t=11.31; all P<0.05]. The incidence of early-onset sepsis was higher in the DRCPAP group than in the non-DRCPAP group [1.8% (68/3 578) vs. 1.3% (193/14 296), adjusted OR (95% CI): 1.417 (1.028-1.955)], while the rates of tracheal intubation within 72 hours, PS use, invasive mechanical ventilation, mortality, admission hypothermia, grade Ⅲ-Ⅳ intracranial hemorrhage, and stage≥3 ROP were all lower in the DRCPAP group compared to the non-DRCPAP group [22.6% (830/3 666) vs. 36.9% (5 310/14 374), adjusted OR (95% CI): 0.499 (0.448-0.555); 53.1% (1 947/3 666) vs. 58.3% (8 388/14 377), adjusted OR (95% CI): 0.764 (0.697-0.836); 30.1% (1 104/3 662) vs. 43.9% (6 307/14 366), adjusted OR (95% CI): 0.539 (0.487-0.595); 7.4% (274/3 666) vs. 10.6% (1 526/14 342), adjusted OR (95% CI): 0.709 (0.601-0.836); 57.5% (2 103/3 657) vs. 66.5% (9 501/14 287), adjusted OR (95% CI): 0.722 (0.661-0.788); 3.0% (101/3 366) vs. 5.9% (763/12 932)], adjusted OR (95% CI): 0.525 (0.412-0.669); 2.2% (65/2 954) vs. 3.3% (367/11 121), adjusted OR (95% CI): 0.692 (0.505-0.947); all P<0.05]. There were no statistically significant differences between the two groups in the incidence rates of BPD at a corrected gestational age of 36 weeks, patent ductus arteriosus ligation, spontaneous intestinal perforation, and pneumothorax. Conclusions:Domestically, the application of DRCPAP might be related to a decrease in the demand for invasive ventilation, the use of surfactants, and mortality, but it might not reduce the occurrence of bronchopulmonary dysplasia, at a corrected gestational age of 36 weeks. In recent years, the use of DRCPAP in very premature infants in China has increased, but the overall usage rate is still low, and there are significant differences between units, requiring continuous quality improvement.

Objective:To investigate the current status, trends, and differences among institutions in the application of delivery room continuous positive airway pressure (DRCPAP) for very preterm infants treated in the institutions in the Chinese Neonatal Network (CHNN). Also, to explore the impact of DRCPAP on the outcomes of very preterm infants in China.Methods:A retrospective cohort study was conducted. Based on the CHNN very preterm infant cohort, very preterm infants (gestational ages ranging from 25 weeks +0 to 31 weeks +6) born in-hospital and treated in 79 tertiary neonatal intensive care units (NICUs) participating in the CHNN from 2019 to 2021 were included. The usage rates of DRCPAP in different hospitals, as well as gestational ages and years, were described. Data were analyzed using the Chi-square test (or Fisher's exact test) or t-test. A multivariate logistic regression model was established to explore the correlation between DRCPAP and clinical outcomes. Results:(1) A total of 18 048 very preterm infants were included. Among them, 3 666 (20.3%) received DRCPAP, and 14 382 (79.7%) did not. (2) The usage rate of DRCPAP for very preterm infants among different institutions is from 0.0% to 94.5%. Fourteen institutions did not use DRCPAP, and 55 institutions had a usage rate below 30%. The usage rate of DRCPAP in very preterm infants increased annually, from 13.8% (818/5 916) in 2019 to 26.0% (1 583/6 097) in 2021 ( χ2trend=122.00, P<0.001). (3) The DRCPAP group had higher rates of maternal assisted reproductive technology pregnancy, chorioamnionitis, a full course of antenatal corticosteroids, gestational diabetes, fetal distress, antenatal magnesium sulfate use, and cesarean delivery compared to the non-DRCPAP group [20.3% (744/3 665) vs. 17.6% (2 529/14 369), χ2=14.45; 23.0% (695/3 021) vs. 16.4% (1 956/11 926), χ2=72.57; 57.1% (2 090/3 660) vs. 54.3% (7 766/14 302), χ2=9.55; 23.0% (844/3 669) vs. 20.7% (2 969/14 342), χ2=9.77; 8.7% (319/3 666) vs. 7.0% (1 006/14 371), χ2=12.51; 87.1% (3 186/3 657) vs. 82.0% (11 736/14 312), χ2=81.38; 63.5% (2 327/3 664) vs. 60.7% (8 722/14 369), χ2=9.59; all P<0.05]. While the incidence of hypertensive disorders of pregnancy and the proportion of infants not using antenatal corticosteroids were lower in the non-DRCPAP group [17.1% (626/3 660) vs. 22.6% (3 183/14 084), χ2=44.70; 14.2% (520/3 661) vs. 19.7% (2 814/14 284), χ2=57.34; all P<0.05]. The DRCPAP group had lower birth weight and gestational age, higher 1 min and 5 min Apgar scores, and lower neonatal transport stabilization index scores [(1 308±314) g vs. (1 325±315) g, t=2.90; (29.5±1.7) weeks vs. (29.7±1.6) weeks, t=3.96; (7.9±1.8) scores vs. (7.6±1.9) scores, t=－9.80; (9.0±1.1) scores vs. (8.7±1.3) scores, t=－13.01; (11.0±9.4) scores vs. (13.1±9.8) scores, t=11.31; all P<0.05]. The incidence of early-onset sepsis was higher in the DRCPAP group than in the non-DRCPAP group [1.8% (68/3 578) vs. 1.3% (193/14 296), adjusted OR (95% CI): 1.417 (1.028-1.955)], while the rates of tracheal intubation within 72 hours, PS use, invasive mechanical ventilation, mortality, admission hypothermia, grade Ⅲ-Ⅳ intracranial hemorrhage, and stage≥3 ROP were all lower in the DRCPAP group compared to the non-DRCPAP group [22.6% (830/3 666) vs. 36.9% (5 310/14 374), adjusted OR (95% CI): 0.499 (0.448-0.555); 53.1% (1 947/3 666) vs. 58.3% (8 388/14 377), adjusted OR (95% CI): 0.764 (0.697-0.836); 30.1% (1 104/3 662) vs. 43.9% (6 307/14 366), adjusted OR (95% CI): 0.539 (0.487-0.595); 7.4% (274/3 666) vs. 10.6% (1 526/14 342), adjusted OR (95% CI): 0.709 (0.601-0.836); 57.5% (2 103/3 657) vs. 66.5% (9 501/14 287), adjusted OR (95% CI): 0.722 (0.661-0.788); 3.0% (101/3 366) vs. 5.9% (763/12 932)], adjusted OR (95% CI): 0.525 (0.412-0.669); 2.2% (65/2 954) vs. 3.3% (367/11 121), adjusted OR (95% CI): 0.692 (0.505-0.947); all P<0.05]. There were no statistically significant differences between the two groups in the incidence rates of BPD at a corrected gestational age of 36 weeks, patent ductus arteriosus ligation, spontaneous intestinal perforation, and pneumothorax. Conclusions:Domestically, the application of DRCPAP might be related to a decrease in the demand for invasive ventilation, the use of surfactants, and mortality, but it might not reduce the occurrence of bronchopulmonary dysplasia, at a corrected gestational age of 36 weeks. In recent years, the use of DRCPAP in very premature infants in China has increased, but the overall usage rate is still low, and there are significant differences between units, requiring continuous quality improvement.

The changes in intestinal flora are usually associated with different gastrointestinal diseases, and intestinal flora homeostasis can enhance immune tolerance and regulate intestinal immune balance.Previous studies have found that the increase of the relative abundance of Bacteroides fragilis (B.fragilis) in Bacteroides intestinalis can significantly enhance the expression of intestinal regulatory T cells (Treg) and anti-inflammatory cytokines, thus alleviating intestinal inflammation.However, the mechanism of B.fragilis regulating intestinal immunity is still unclear.In this study, an acute colitis model was constructed by giving 3% DSS in drinking water solution to SPF-grade C57BL/6 mice for 7 days, and exogenous supplementation B.fragilis was given to mice by gastric gavage to study its regulatory effect on intestinal immunity and its mechanism of action.The results showed that B.fragilis could improve the intestinal flora disorder in mice with colitis and increase the content of short-chain fatty acids (SCFAs), the main metabolite of the intestinal flora.By extracting mouse tissue lymphocytes, naive CD4+ T cells, and liposome-modified siRNA knockdown mouse Smad3, it was further discovered by flow cytometry that B.fragilis induced the expression of intestinal Treg cells and related cytokines through the TGF-β/Smad3 signaling pathway, which enhanced intestinal regulatory immunity and alleviated colitis.It was also found that B.fragilis activated TGF-β by increasing the expression of reactive oxygen species (ROS), thus inducing Treg cell differentiation and playing an immunomodulatory role.