Objective To investigate the regulatory role of the programmed cell death protein 1 (PD-1) and its ligand programmed cell death protein ligand 1 (PD-L1) signaling on the subtypes and functions of natural killer (NK) cells at the maternal-fetal interface during the second trimester in mice following Toxoplasma gondii infection during the first trimester. Methods Twelve 6- to 8-week-old female mice of the C57BL/6J strain were divided into a control group and an infection group, of 6 mice in each group. On the 6.5th day of pregnancy (Gd6.5), each pregnant mouse in the infection group was intraperitoneally injected with 150 tachyzoites of the Toxoplasma gondii PRU strain, while mice in the control group were injected with an equal volume of physiological saline. On the 12.5th day of pregnancy (Gd12.5), uterus and placenta tissues were sampled from pregnant mice for pathological observations, and the mRNA expression levels of PD-1, PD-L1, and tumor necrosis factor-α (TNF-α) were quantified in uterus and placenta tissues. The PD-1 and DX5 expression was measured on NK cells at the maternal-fetal interface using flow cytometry. In addition, the in vitro JEG-3 trophoblast cells and NK-92MI cells co-culture system was established as the control group, and the addition of T. gondii tachyzoites in the co-culture system served as the infection group. The PD-1, PD-L1, and DX5 mRNA expression was quantified in cells using real-time fluorescence quantitative reverse transcription PCR (RT-qPCR) assay, and the TNF-α concentration was measured in the cell culture supernatant using enzyme-linked immunosorbent assay (ELISA). Results On Gd12.5, clear and intact cellular structures of placental decidual tissues were seen in pregnant mice in the control group, with no remarkable abnormal changes found in the uterine columnar epithelial cells, and inflammatory cell infiltration and blood stasis at varying degrees were found in uterine and placental tissues from pregnant mice in the infection group. The relative PD-1, PD-L1, and TNF-α mRNA expression was (1.004 ± 0.004), (1.001 ± 0.001), and (1.001 ± 0.001) in uterine tissues from pregnant mice in the control group and (2.480 ± 0.720), (3.355 ± 0.920), and (2.391 ± 0.073) in the infection group, respectively. The relative PD-1, PD-L1, and TNF-α mRNA expression was (1.007 ± 0.010), (1.006 ± 0.006), and (1.001 ± 0.001) in the uterine tissues in the control group and (6.948 ± 1.918), (3.225 ± 1.034), and (1.536 ± 0.150) in the infection group, respectively. The relative PD-1, PD-L1, and TNF-α mRNA expression was higher in both the uterine (t = 3.55, 4.43 and 33.02, all P values < 0.05) and placental tissues (t = 5.36, 3.72 and 6.18, all P values < 0.05) in the infection group than in the control group. Flow cytometry showed that the proportions of PD-1⁺ NK cells, PD-1⁺ DX5⁺ NK cells, and DX5⁺ NK cells were (12.200 ± 1.082)%, (9.373 ± 7.728)%, and (44.000 ± 4.095)% in uterine tissues from pregnant mice in the control group, and (21.733 ± 1.630)%, (18.767 ± 1.242)%, and (73.367 ± 0.611)% in the infection group, respectively. The proportions of PD-1⁺ NK cells, PD-1⁺ DX5⁺ NK cells, and DX5⁺ NK cells were (1.100 ± 0.510)%, (2.277 ± 1.337)%, and (96.167 ± 2.831)% in placental tissues from mice in the control group, and (26.867 ± 9.722)%, (23.433 ± 6.983)%, and (82.467 ± 2.248)% in the infection group, respectively. The proportions of PD-1⁺ NK cells (t = 8.45, P < 0.05) and DX5⁺ NK cells (t = 12.29, P < 0.05) were higher in uterine tissues from pregnant mice in the infection group than in the control group, and no significant difference was seen in the proportion of PD-1⁺ DX5⁺ NK cells (Z = -1.09, P > 0.05). The proportions of PD-1⁺ NK cells (t = 4.58, P < 0.05) and PD-1⁺ DX5⁺ NK cells (t = 5.15, P < 0.05) were higher in placental tissues from pregnant mice in the infection group than in the control group, while the proportion of DX5⁺ NK cells was lower in the infection group than in the control group (t = -6.56, P < 0.05). RT-qPCR assay revealed that the relative PD-1, PD-L1, and DX5 mRNA expression was (1.010 ± 0.005), (1.002 ± 0.003), and (1.001 ± 0.001) in the JEG-3 cells and NK92MI cells co-culture system and (3.638 ± 1.258), (0.397 ± 0.158), and (4.267 ± 1.750) in the control group, and ELISA measured that the TNF-α concentration was higher in the cell culture supernatant in the infection group [(22.056 ± 3.205) pg/mL] than in the control group [(12.441 ± 0.001) pg/mL] (t = 5.20, P < 0.05). The PD-1(t = 3.62, P < 0.05) and DX5 mRNA expression (t = 3.23, P < 0.05) was higher in the infection group than in the control group, and the PD-L1 mRNA expression was lower in the infection group than in the control group (t = -6.63, P < 0.05). Conclusions Following T. gondii infection, both PD-L1 expression and PD-1 expression on DX5⁺ NK cells at the maternal-fetal interface are upregulated in mice during the second trimester; however, the proportion of DX5⁺ NK cells decreases. These findings suggest that PD-1/PD-L1 signaling may suppress NK cell functions by modulating DX5⁺ NK cell subsets.

Octapeptin has strong antibacterial activity against Gram-negative bacteria such as Escherichia coli, Klebsiella pneumoniae and Acinetobacter baumannii, while it also has activity against some Gram-positive bacteria. This study used natural octapeptin A3 and B3 as lead compounds for structural modification. Twenty-one peptide derivatives (including A3 and B3) containing eight amino acid residues were prepared by solid-phase synthesis, and evaluated for antibacterial activity and renal cytotoxicity. Among them, three compounds 6, 7 and 17 exhibited broad-spectrum antibacterial activity and significantly enhanced the activity for Gram-positive bacteria while maintaining the activity of Gram-negative bacteria. Several compounds improved the activity for Pseudomonas aeruginosa. Compound 7 was active against all test strains and had relatively low renal cytotoxicity. The results provide a basis for the further development of novel polypeptide antibiotics.

AIM:To explore the therapeutic effect of teprenone(geranylgeranylacetone,GGA)on lipopolysac-charide(LPS)-induced cardiac dysfunction and its mechanism.METHODS:(1)Eight-week-old male C57BL/6 wild-type mice and carboxyl terminus of heat shock protein 70(HSP70)-interacting protein(CHIP)gene knockout mice were randomly divided into control group,LPS group,LPS+GGA group and GGA group,with 8 mice in each group.The model was established by intraperitoneal injection of LPS(25 mg/kg),and 1 h after LPS stimulation,mice were given intraperito-neal injection of GGA(100 mg/kg).The technique of high-resolution ultrasonography system was used to evaluate the car-diac function of mice.The serum of mice from each group were collected to detect the levels of creatine kinase-MB(CK-MB)and lactate dehydrogenase(LDH).HE staining was performed to observe histological changes of cardiac tissues.ELISA was used to detect the levels of tumor necrosis factor-α(TNF-α)and interleukin-6(IL-6)in cardiac tissues.West-ern blot was used to detect the protein levels of HSP70,CHIP,karyopherin-α 2(KPNA2),myeloperoxidase(MPO),vas-cular cell adhesion molecule(VCAM),intercellular cell adhesion molecule(ICAM),and nuclear factor-κB(NF-κB)in cardiac tissues.(2)In vitro cell inflammation model was established using mouse myocardial cells HL-1 stimulated with LPS.ELISA was used to detect the levels of TNF-α and IL-6 in cell supernatants.Western blot was used to detect the pro-tein expression levels of HSP70,CHIP,and KPNA2 in myocardial cells.Immunofluorescence staining was performed to observe the content of nuclear NF-κB.RESULTS:(1)GGA effectively improved cardiac function of LPS-stimulated mice,significantly increased ejection fraction and left ventricular fractional shortening(P<0.01),reduced serum levels of CK-MB and LDH(P<0.01),and alleviated myocardial injury.(2)GGA significantly reduced the release of TNF-α and IL-6 caused by LPS(P<0.01),as well as nuclear translocation of NF-κB,decreased the levels of KPNA2,MPO,VCAM and ICAM in cardiac tissues,and increased the levels of HSP70 in cardiac tissues and cells(P<0.01).(3)In CHIP knockout myocardial cells and mice,GGA failed to inhibit LPS-induced inflammatory response and lost its effect on im-proving cardiac function.CONCLUSION:The protective effect of GGA against LPS-caused cardiac dysfunction of mice is related to increasing expression of HSP70 and promoting CHIP activation,which inhibits the translocation of NF-κB into nucleus and suppresses inflammatory factor release.CHIP knockout abolishes the effects of GGA on reducing LPS-induced inflammatory response and myocardial injury.

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.

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 protective effect of HMS5552 on pancreatic islet β-cell injury in diabetic rats and study the mechanism.Methods A total of 40 SD rats were fed with high-sugar and high-fat diet for 8 weeks combined with intraperitoneal injection of streptozotocin(STZ)to induce type 2 diabetic rat models.The successful model rats were divided into model group(0.9％NaCl by gavage)and experimental group(30 mg·kg-1 HMS5552 by gavage).The other 20 normal rats served as the normal group(0.9％NaCl was given by gavage).Hematoxylin-eosin(HE)staining was used to detect the pathological changes of pancreatic islets.The INS-1 cells were divided into blank group(normal cultured),model group(high-sugar and high-fat culture medium)and experimental-L,-M,-H groups(high-sugar and high-fat culture medium+0.3,3.0 and 30.0 μmol·L-1 HMS5552).The viability of INS-1 cells was detected by cell counting kit-8(CCK-8)method,the apoptosis of INS-1 cells was detected by Annexin V/PI method,the mRNA expression level of B cell lymphocytoma 2(Bcl-2)was detected by real-time fluorescence quantitative polymerase chain reaction(RT-qPCR)method;the expression level of phosphoinositide 3-kinase/protein kinase B(PI3K/AKT)pathway and apoptosis protein was detected by western blotting.Results HE staining showed that the pathological damage of pancreas in the experimental group rats was significantly less than that in the model group.The cell viability of the blank group,model group and experimental-L,-M,-H groups were(99.67±2.40)％,(48.18±4.18)％,(61.74±4.78)％,(70.74±6.36)％and(78.30±4.68)％,respectively;apoptosis rates were(10.40±4.66)％,(48.60±3.27)％,(35.90±4.45)％,(28.07±5.35)％and(18.30±3.04)％,respectively;the relative expression levels of Bcl-2 mRNA were 1.00±0.03,0.32±0.04,0.59±0.05,0.62±0.04 and 0.72±0.12,respectively;phosphorylated PI3K(p-PI3K)/PI3K ratios were 1.00±0.00,0.34±0.05,0.46±0.02,0.64±0.01 and 0.81±0.01,respectively;phosphorylated AKT(p-AKT)/AKT ratios were 1.00±0.00,0.28±0.12,0.63±0.02,0.74±0.06 and 0.87±0.09,respectively.The above indexes in the model group compared with the blank group,the differences between the above indexes of the experimental-L,-M,-H groups and the model group were statistically significant(P＜0.05,P＜0.01).Conclusion HMS5552 can improve glucose metabolism in diabetic rats and protect pancreatic β-cells by regulating the expression of PI3K/AKT signaling pathway.

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 protective effect of HMS5552 on pancreatic islet β-cell injury in diabetic rats and study the mechanism.Methods A total of 40 SD rats were fed with high-sugar and high-fat diet for 8 weeks combined with intraperitoneal injection of streptozotocin(STZ)to induce type 2 diabetic rat models.The successful model rats were divided into model group(0.9％NaCl by gavage)and experimental group(30 mg·kg-1 HMS5552 by gavage).The other 20 normal rats served as the normal group(0.9％NaCl was given by gavage).Hematoxylin-eosin(HE)staining was used to detect the pathological changes of pancreatic islets.The INS-1 cells were divided into blank group(normal cultured),model group(high-sugar and high-fat culture medium)and experimental-L,-M,-H groups(high-sugar and high-fat culture medium+0.3,3.0 and 30.0 μmol·L-1 HMS5552).The viability of INS-1 cells was detected by cell counting kit-8(CCK-8)method,the apoptosis of INS-1 cells was detected by Annexin V/PI method,the mRNA expression level of B cell lymphocytoma 2(Bcl-2)was detected by real-time fluorescence quantitative polymerase chain reaction(RT-qPCR)method;the expression level of phosphoinositide 3-kinase/protein kinase B(PI3K/AKT)pathway and apoptosis protein was detected by western blotting.Results HE staining showed that the pathological damage of pancreas in the experimental group rats was significantly less than that in the model group.The cell viability of the blank group,model group and experimental-L,-M,-H groups were(99.67±2.40)％,(48.18±4.18)％,(61.74±4.78)％,(70.74±6.36)％and(78.30±4.68)％,respectively;apoptosis rates were(10.40±4.66)％,(48.60±3.27)％,(35.90±4.45)％,(28.07±5.35)％and(18.30±3.04)％,respectively;the relative expression levels of Bcl-2 mRNA were 1.00±0.03,0.32±0.04,0.59±0.05,0.62±0.04 and 0.72±0.12,respectively;phosphorylated PI3K(p-PI3K)/PI3K ratios were 1.00±0.00,0.34±0.05,0.46±0.02,0.64±0.01 and 0.81±0.01,respectively;phosphorylated AKT(p-AKT)/AKT ratios were 1.00±0.00,0.28±0.12,0.63±0.02,0.74±0.06 and 0.87±0.09,respectively.The above indexes in the model group compared with the blank group,the differences between the above indexes of the experimental-L,-M,-H groups and the model group were statistically significant(P＜0.05,P＜0.01).Conclusion HMS5552 can improve glucose metabolism in diabetic rats and protect pancreatic β-cells by regulating the expression of PI3K/AKT signaling pathway.

【Objective】 To investigate the protection of astragaloside IV from high glucose induced podocyte injury and mitochondrial dysfunction and its molecular mechanisms. 【Methods】 The model of podocyte injury induced by high glucose (30 mmol/L glucose) was established, and the model cells were treated with low, medium and high doses of astragaloside IV respectively; cell activity was detected by CCK-8. Apoptosis was detected by TUNEL staining. Mitochondrial membrane potential was detected by JC-1 fluorescence probe. ATP content was detected by the kit. The expression levels of apoptosis and podocyte injury related proteins and Notch pathway related proteins were detected by Western blotting. 【Results】 Compared with the control group, cell activity was decreased, apoptosis level was increased (P<0.05), anti-apoptotic protein (Bcl2) expression was decreased, and apoptosis protein (Bax, cleaved-caspase 9, cleaved-caspase 3) expressions were increased (all P<0.05) in HG group. Compared with HG group, HG+AS-IV improved cell activity and apoptosis level induced by high glucose (P<0.05), increased expression of anti-apoptotic protein (Bcl2), and decreased expressions of apoptotic protein (Bax, cleaved-caspase 9, and cleaved-caspase 3) (all P<0.05). Compared with the control group, mitochondrial dysfunction occurred in HG group, JC-1 monomer content increased, and ATP content decreased (all P<0.05). Compared with HG group, HG+AS-IV improved mitochondrial dysfunction, increased JC-1 polymer content and ATP content (P<0.05). In addition, compared with the control group, the expression of Notch pathway-related protein was decreased in HG group (P<0.05). Compared with HG group, Notch pathway-related protein expression was increased in HG+AS-IV group (all P<0.05). Molecular docking results showed that AS-IV could bind Notch1. 【Conclusion】 Astragaloside IV can improve podocyte injury and mitochondrial dysfunction induced by high glucose, possibly by inhibiting Notch pathway activation.

To identify the active constituents in vitro and blood-absorbed ingredients in vivo from Yin Chen Hao decoction provides scientific evidence for probing its prevention and treatment mechanism on acute liver injury. An ultrahigh performance liquid chromatography quadrupole-time of flight-mass spectrometry (UPLC-QTOF/MS) method was applied for analysis of Yin Chen Hao decoction and the serum samples of mice with con-A induced acute liver injury after preventive oral administration for 14 days (the use of all laboratory animals in this study was approved by the Ethics Committee of the Naval Medical University, 19YF1459400). A total of 90 chemical constituents were identified from Yin Chen Hao decoction, mainly were flavonoids, terpenoids, tannins, quinones. 5 prototype compounds were identified in the serum, including chrysophanol, deoxyrhapontin-8-O-gallate, mussaenosidic acid, herniarin, emodin. The established UPLC-QTOF/MS method could efficiently and sensitively identify the constituents in vitro and blood-absorbed ingredients of Yin Chen Hao decoction, primarily clarify the material basis of its hepatoprotective effect, and provided a scientific basis for the quality marker selection and the pharmacodynamic material basis research on the decoction.