Objective To explore the effect of intestinal nitrates on the growth of Klebsiella pneumoniae and its regulatory mechanisms. Methods K. pneumoniae strains with nitrate reductase narG and narZ single or double gene knockout or with NarXL gene knockout were constructed and observed for both aerobic and anaerobic growth in the presence of KNO3 using an automated bacterial growth analyzer and a spectrophotometer, respectively. The mRNA expressions of narG and narZ in K. pneumoniae in anaerobic cultures in the presence of KNO3 and the effect of the binary regulatory system NarXL on their expresisons were detected using qRT-PCR. Electrophoretic mobility shift assays (EMSA) and MST analysis were performed to explore the specific regulatory mechanisms of NarXL in sensing and utilizing nitrates. Competitive experiments were conducted to examine anaerobic growth advantages of narG and narZ gene knockout strains of K. pneumoniae in the presence of KNO3. Results The presence of KNO3 in anaerobic conditions, but not in aerobic conditions, promoted bacterial growth more effectively in the wild-type K. pneumoniae strain than in the narXL gene knockout strain. In anaerobic conditions, the narXL gene knockout strain showed significantly lowered mRNA expressions of narG and narZ (P<0.0001). EMSA and MST experiments demonstrated that the NarXL regulator could directly bind to narG and narZ promoter regions. The wild-type K. pneumoniae strain in anaerobic cultures showed significantly increased expressions of narG and narZ mRNAs in the presence of KNO3 (P<0.01), and narG gene knockout resulted in significantly attenuated anaerobic growth and competitive growth abilities of K. pneumoniae in the presence of KNO3 (P<0.01). Conclusion The binary regulatory system NarXL of K. pneumoniae can sense changes in intestinal nitrate concentration and directly regulate the expression of nitrate reductase genes narG and narZ to promote bacterial growth.

Objective: To understand and assess the current situation of primary and secondary school students health services in community health service organizations in Shenzhen, so as to provide a basis for upgrading the capacity of health services. Methods: A total of 684 community health service organizations and 587 part time health vice principals in the Shenzhen City were selected for the study in June 2022, and the special questionnaire surveys regarding primary and secondary school students health service capacity and the community health service organizations and part time health vice principals performance ability were administered in Shenzhen. SPSS 26.0 software was used for a descriptive analysis. Results: The staffing rate of general practitioners or clinical physicians in Shenzhen s community health service organizations was 99.9%, 67.1% of community health service organizations established counterpart collaborative relationships with schools, 50.8% of community health service organizations provided diagnostic and treatment services for students, 24.8% of community health service organizations provided health check up services for students, 85.2% of community health service organizations provided health guidance to schools, and 94.3% of community health service organizations had a part time vice principal of health with a score of (7.63±1.59) in the self assessment of their ability to carry out their duties, and space constraints and shortage of nursing were the main problems in promoting student medical check ups in the community health service organizations. Conclusions The community health service organizations in Shenzhen suffer from inadequate medical service resources and inadequate training for professional staff, resulting in low service capacity for providing physical examinations and health management for primary and secondary school students. There is a need to further promote the integrated development of education and health, and continuously enhance service capabilities, to promote the orderly development of student health work.

Objective To explore the effect of intestinal nitrates on the growth of Klebsiella pneumoniae and its regulatory mechanisms. Methods K. pneumoniae strains with nitrate reductase narG and narZ single or double gene knockout or with NarXL gene knockout were constructed and observed for both aerobic and anaerobic growth in the presence of KNO3 using an automated bacterial growth analyzer and a spectrophotometer, respectively. The mRNA expressions of narG and narZ in K. pneumoniae in anaerobic cultures in the presence of KNO3 and the effect of the binary regulatory system NarXL on their expresisons were detected using qRT-PCR. Electrophoretic mobility shift assays (EMSA) and MST analysis were performed to explore the specific regulatory mechanisms of NarXL in sensing and utilizing nitrates. Competitive experiments were conducted to examine anaerobic growth advantages of narG and narZ gene knockout strains of K. pneumoniae in the presence of KNO3. Results The presence of KNO3 in anaerobic conditions, but not in aerobic conditions, promoted bacterial growth more effectively in the wild-type K. pneumoniae strain than in the narXL gene knockout strain. In anaerobic conditions, the narXL gene knockout strain showed significantly lowered mRNA expressions of narG and narZ (P<0.0001). EMSA and MST experiments demonstrated that the NarXL regulator could directly bind to narG and narZ promoter regions. The wild-type K. pneumoniae strain in anaerobic cultures showed significantly increased expressions of narG and narZ mRNAs in the presence of KNO3 (P<0.01), and narG gene knockout resulted in significantly attenuated anaerobic growth and competitive growth abilities of K. pneumoniae in the presence of KNO3 (P<0.01). Conclusion The binary regulatory system NarXL of K. pneumoniae can sense changes in intestinal nitrate concentration and directly regulate the expression of nitrate reductase genes narG and narZ to promote bacterial growth.

Background/Aims: Metabolic dysfunction-associated steatotic liver disease (MASLD) has become an increasingly important health challenge, with a substantial rise linked to changing lifestyles and global obesity. Ursolic acid, a natural pentacyclic triterpenoid, has been explored for its potential therapeutic effects. Given its multifunctional bioactive properties, this research further revealed the pharmacological mechanisms of ursolic acid on MASLD. Methods: Drug target chips and bioinformatics analysis were combined in this study to explore the potential therapeutic effects of ursolic acid on MASLD. Molecular docking simulations, surface plasmon resonance analyses, pull-down experiments, and co-immunoprecipitation assays were used to verify the direct interactions. Gene knockdown mice were generated, and high-fat diets were used to validate drug efficacy. Furthermore, initial CD4+ T cells were isolated and stimulated to demonstrate our findings. Results: In this study, the multifunctional extracellular matrix phosphorylated glycoprotein secreted phosphoprotein 1 (SPP1) was investigated, highlighting its capability to induce Th17 cell differentiation, amplifying inflammatory cascades, and subsequently promoting the evolution of MASLD. In addition, this study revealed that in addition to the canonical TGF-β/IL-6 cytokine pathway, SPP1 can directly interact with ITGB1 and CD44, orchestrating Th17 cell differentiation via their joint downstream ERK signaling pathway. Remarkably, ursolic acid intervention notably suppressed the protein activity of SPP1, suggesting a promising avenue for ameliorating the immunoinflammatory trajectory in MASLD progression. Conclusions Ursolic acid could improve immune inflammation in MASLD by modulating SPP1-mediated Th17 cell differentiation via the ERK signaling pathway, which is orchestrated jointly by ITGB1 and CD44, emerging as a linchpin in this molecular cascade.

Objective: To analyze the correlation between third molar agenesis and craniofacial morphology by studying the location and number of congenital missing third molars and results of craniofacial cephalometric measurement. Methods: A total of 123 patients were included, including 64 patients in the control group without congenital third molar absence and 59 patients in the absence group with at least one third molar absent. Cephalometric measurements included FMA, IMPA, AR-Go, GoGn-Sn, Co-A, Co-Gn, ANS-Me, Go-Me, SN-MP, Ar-Go-Me, SNA, SNB, ANB, Y-axis angle, Y-axis length, Ar-Go, Go-Me, MP-OP, FH-PP, FH-OP, a total of 18 bone tissue indicators, U1-SN, U1-L1, U1-NA, L1-NB, U1-APo and L1-APo, a total of 6 dental indicators, and UL-EP, LL-EP and nasolabial angle, a total of 3 soft tissue indicators. The correlation between congenital agenesis of third molars and craniofacial morphology was analyzed. Results: The most common missing location of the third molar occured in the upper jaw and the most common number of missing teeth was one. In control group, Ar-Go-Me and SN-MP were larger (P<0.05), U1-SN, U1-NA, L1-NB, UL-EP and LL-EP were larger (P<0.05), and U1-L1 was smaller (P<0.01). There were no significant differences in Ar-Go and Go-Me between the two groups(P>0.05). Conclusion Patients with four third molars are more likely to have backward and downward rotation of the mandible and are more likely to develop into a convex facial type than patients with missing third molars, which has a higher correlation with hyperdivergent growth pattern and convex facial type.

Objective:To investigate the related mechanism of IL-17B in regulating host immune response by studying the role and mechanism of IL-17B in the infection of Listeria monocytogenes in mice. Methods:Eighteen male C57BL/6 mice were randomly divided into three groups with six in each group: control group, PBS group and wild-type (WT) group. The control group was not given any treatment. The mice in the PBS group were injected with 100 μl of sterile PBS, while C57BL/6 mice in the WT group and IL-17B deficient (IL-17B -/-) male mice were injected intravenously with 100 μl of Listeria monocytogenes 19115 (2×10 4 colony forming unit). The mice were sacrificed 48 h after infection and then peripheral blood, spleen and liver samples were collected. Bacterial colonization in mouse spleen and liver was detected by plate count method; HE staining was used to evaluate histopathological damages; flow cytometry was used to detect the immune cells in different tissues. ELISA and qRT-PCR were used to detect the levels of IL-1β, IL-6, IL-12p40, TNF-α, IFN-γ and iNOS in serum and spleen. qRT-PCR were used to detect the expression of IL-17B and IL-17RB. Results:Bacterial colonization in mouse spleen was reduced in the IL-17B -/- group as compared with that in the WT group ( P<0.05). Compared with the PBS group, Listeria monocytogenes infection increased the expression of IL-17B and IL-17RB in mouse spleen ( P<0.05, P<0.01). There was no significant difference in the pathological damages in spleen between WT and IL-17B -/- groups. Moreover, compared with the WT group, the IL-17B -/- group showed increased macrophages, M1 macrophages ( P<0.01) and NK cells ( P<0.05) in spleen, up-regulated macrophages ( P<0.05) and M1 macrophages ( P<0.01) in the peripheral blood, enhanced expression of IL-6 in serum and spleen ( P<0.05), and promoted expression of IL-6, IL-12, IL-1β, TNF-α, IFN-γ and iNOS in spleen. Conclusions:IL-17B might inhibit Listeria monocytogenes clearance by inhibiting macrophage infiltration and the secretion of IL-6.

COVID-19 is caused by a novel coronavirus-severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2), which has being spreading around the world, posing a serious threat to human health and lives. Neutralizing antibodies and small molecule inhibitors for virus replication cycle are the main antiviral treatment for novel coronavirus recommended in China. To further promote the rational use of antiviral therapy in clinical practice, the National Center for Infectious Diseases (Beijing Ditan Hospital Capital Medical University and the First Affiliated Hospital, Zhejiang University School of Medicine) invited experts in fields of infectious diseases, respiratory and intensive care to develop an Expert Consensus on Antiviral Therapy of COVID-19 based on the Diagnosis and Treatment Guideline for COVID-19 ( trial version 10) and experiences in the diagnosis and treatment of COVID-19 in China. The consensus is concise, practical and highly operable, hopefully it would improve the understanding of antiviral therapy for clinicians and provide suggestions for standardized medication in treatment of COVID-19.

Objective: To investigate the prevalence and influencing factors of electronic cigarette (e-cigarette) use among adolescents in Haidian District, Beijing, so as to provide insights into tobacco control among adolescents. Methods: The students in junior high school, high school and vocational high school were recruited from Haidian District using the stratified cluster random sampling method in October of 2019, and subjects' demographic features and use of e-cigarettes were collected using the Questionnaire for Survey on Tobacco Prevalence among Adolescents in China in 2019. The factors affecting e-cigarette use were identified among adolescents using the multivariable logistic regression analysis. Results: A total of 658 adolescents were investigated, including 315 junior high school students ( 47.87% ), 221 high school students ( 33.59% ), and 122 vocational high school students ( 18.54% ), and there were 261 boys ( 39.66% ), and 397 girls ( 60.34% ). There were 605 students that had heard of electronic cigarettes ( 91.95% ), 63 students that had used e-cigarettes (9.57%), and 23 students with current use of e-cigarettes ( 3.50% ), and there were 39 students that had never used electronic cigarettes but had a tendency of use in the future ( 6.55% ). Multivariable logistic regression analysis identified parental smoking ( OR=2.408, 95%CI: 1.179-4.916 ), close friends' smoking ( OR=3.597, 95%CI: 1.715-7.544 ) and cigarette smoking ( OR=23.029, 95%CI: 11.092-47.812 ) as factors affecting e-cigarette use among adolescents. Conclusions The prevalence of electronic cigarette uses is 9.57% among adolescents in Haidian District, Beijing. Parental smoking, peer smoking and use of cigarettes may facilitate the use of e-cigarettes among adolescents.

Background: The incidence of inflammatory bowel disease (IBD) is increasing yearly, some of the IBD patients have extraintestinal manifestations (EIM), and EIM has impact on the treatment of IBD. Aims: To summarize the clinical characteristics of IBD patients associated with EIM, and evaluate the therapeutic effect of infliximab (IFX). Methods: The clinical data of IBD patients associated with EIM from January 2010 to December 2020 at the First Affiliated Hospital of Dalian Medical University were retrospectively analyzed, and the therapeutic effect of IFX was investigated. Results: In 811 patients with IBD, 50 (6.17%) patients had EIM. The commonly seen EIM was arthritis (78.00%) and erythema nodosum (26.00%); 52.00% had one EIM; 68.42% of UC patients with EIM involved E3, and 50.00% of CD patients with EIM involved L3. A total of 21 patients received IFX treatment, 2 weeks after medication, HB and ALB significantly increased, while ESR, CRP and PLT significantly decreased. Twenty⁃two weeks after medication, 83.33% of UC patients turned mild, and 70.00% of CD patients entered the remission phase. After the use of IFX, the first disappearance time of arthritis was significantly decreased when compared with those without using IFX (2.50 days vs. 10.50 days, P<0.05). The median time for the first disappearance of arthritis in patients with elevated CRP was significantly decreased than in patients with normal CRP (3.00 days vs. 9.00 days, P<0.05). Conclusions: Arthritis and erythema nodosum are common EMI in patients with IBD, and the treatment with IFX can significantly shorten the time of the first disappearance of some EIM.