The outer membrane composed predominantly of lipopolysaccharide (LPS) is an essential biological barrier for most Gram-negative (G^-) bacteria. Lipopolysaccharide transport protein (Lpt) complex LptDE is responsible for the critical final stage of LPS transport and outer membrane assembly. The structure and function of LptDE are highly conserved in most G^- bacteria but absent in mammalian cells, and thus LptDE complex is regarded as an attractive antibacterial target. In recent 10 years, the deciphering of the three-dimensional structure of LptDE protein facilities the drug discovery based on such "non-enzyme" proteins. Murepavadin, a peptidomimetic compound, was reported to be the first compound able to target LptD, enlightening a new class of antibacterial molecules with novel mechanisms of action. This article is devoted to summarize the molecular characteristics, structure-function of LptDE protein complex and review the development of murepavadin and related peptidomimetic compounds, in order to provide references for relevant researches.

Objective:To report the results of national surveillance on the distribution and antimicrobial resistance profile of clinical Gram-negative bacteria isolates from bloodstream infections in China in 2022.Methods:The clinical isolates of Gram-negative bacteria from blood cultures in member hospitals of national bloodstream infection Bacterial Resistant Investigation Collaborative System（BRICS）were collected during January 2022 to December 2022. Antibiotic susceptibility tests were conducted by agar dilution or broth dilution methods recommended by Clinical and Laboratory Standards Institute（CLSI）. WHONET 5.6 and SPSS 25.0 software were used to analyze the data.Results:During the study period，9 035 strains of Gram-negative bacteria were collected from 51 hospitals，of which 7 895（87.4%）were Enterobacteriaceae and 1 140（12.6%）were non-fermenting bacteria. The top 5 bacterial species were Escherichia coli（ n=4 510，49.9%）， Klebsiella pneumoniae（ n=2 340，25.9%）， Pseudomonas aeruginosa（ n=534，5.9%）， Acinetobacter baumannii complex（ n=405，4.5%）and Enterobacter cloacae（ n=327，3.6%）. The ESBLs-producing rates in Escherichia coli， Klebsiella pneumoniae and Proteus spp. were 47.1%（2 095/4 452），21.0%（427/2 033）and 41.1%（58/141），respectively. The prevalence of carbapenem-resistant Escherichia coli（CREC）and carbapenem-resistant Klebsiella pneumoniae（CRKP）were 1.3%（58/4 510）and 13.1%（307/2 340）；62.1%（36/58）and 9.8%（30/307）of CREC and CRKP were resistant to ceftazidime/avibactam combination，respectively. The prevalence of carbapenem-resistant Acinetobacter baumannii（CRAB）complex was 59.5%（241/405），while less than 5% of Acinetobacter baumannii complex was resistant to tigecycline and polymyxin B. The prevalence of carbapenem-resistant Pseudomonas aeruginosa（CRPA）was 18.4%（98/534）. There were differences in the composition ratio of Gram-negative bacteria in bloodstream infections and the prevalence of main Gram-negative bacteria resistance among different regions，with statistically significant differences in the prevalence of CRKP and CRPA（ χ2=20.489 and 20.252， P<0.001）. The prevalence of CREC，CRKP，CRPA，CRAB，ESBLs-producing Escherichia coli and Klebsiella pneumoniae were higher in provinicial hospitals than those in municipal hospitals（ χ2=11.953，81.183，10.404，5.915，12.415 and 6.459， P<0.01 or <0.05），while the prevalence of CRPA was higher in economically developed regions（per capita GDP ≥ 92 059 Yuan）than that in economically less-developed regions（per capita GDP <92 059 Yuan）（ χ2=6.240， P=0.012）. Conclusions:The proportion of Gram-negative bacteria in bloodstream infections shows an increasing trend，and Escherichia coli is ranked in the top，while the trend of CRKP decreases continuously with time. Decreasing trends are noted in ESBLs-producing Escherichia coli and Klebsiella pneumoniae. Low prevalence of carbapenem resistance in Escherichia coli and high prevalence in CRAB complex have been observed. The composition ratio and antibacterial spectrum of bloodstream infections in different regions of China are slightly different，and the proportion of main drug resistant bacteria in provincial hospitals is higher than those in municipal hospitals.

AIM:To study the expression of glucose transporters(GLUTs)and silent information regulators(SIRTs/sirtuins)in the liver of diabetic rats and human hepatocytes(LO2 cells)treated with high glucose.METHODS:(1)Twenty male SD rats were randomly divided into normal control(NC)group and diabetes mellitus(DM)group.The rats in DM group were given single intraperitoneal injection of streptozotocin(STZ,60 mg/kg)to establish the DM model,while the rats in NC group were intraperitoneally injected with equal volume of solvent once.Fasting blood glucose(FBG)and body mass were measured every 2 weeks.After 12 weeks of rearing,the blood and liver tissues of the rats were ob-tained after anesthesia with 1%sodium pentobarbitone,the biochemical indicators of blood were detected,and the liver in-dex was calculated.Hematoxylin-eosin(HE)staining and periodic acid-Schiff(PAS)staining were used to observe liver histopathological changes.Lipid accumulation in liver tissues was detected by oil red O staining.The expression levels of GLUTs and SIRTs family member proteins were detected in rat liver tissues.(2)The LO2 cells were treated with different concentrations of glucose for 48 h.The viability of the cells in each group was measured by CCK-8 assay,and Western blot was used to detected the protein expression levels of GLUTs and SIRTs in the cells.RESULTS:(1)Compared with NC group,the rats in DM group were depressed,lost weight,and the FBG and liver index were significantly increased(P＜0.05).The results of HE staining showed that the hepatic sinuses were dilatated and congested near the central vein in DM rats,and mild edema and scattered infiltration of inflammatory cells were found in liver cells.The results of oil red O staining showed the red fat droplets were diffusely scattered within liver cells in DM group.The results of PAS staining showed that there were numerous diffuse light purple circular droplets in the cytoplasm of the liver cells in the central ve-nous area of the DM rats.Western blot showed that the protein levels of GLUTs were higher and the protein levels of SIRTs were lower than those in NC group(P＜0.01).(2)The results of CCK-8 assay showed that the viability of LO2 cells was increased in 50 mmol/L glucose group(P＜0.01),without significant difference in 75,100 and 125 mmol/L glucose groups(all P＞0.05),and decreased in 150,175 and 200 mmol/L glucose groups(all P＜0.01).Later,150 mmol/L glu-cose was used as the high-glucose intervention condition.Western blot showed that the protein levels of GLUTs and SIRTs in LO2 cells under high glucose intervention were consistented with the results in animal experiments.CONCLUSION:High concentration of glucose can cause liver damage in SD rats and reduce the viability of human hepatocytes(LO2 cells).It can also increase the expression of GLUTs and decrease the expression of SIRTs in rat liver tissues and LO2 cells.Therefore,GLUTs and SIRTs family members may be the target proteins of diabetes-induced liver injury.

Objective To observe the efficacy and safety of Morinda officinalis oligosaccharides in the continuation treatment of mild and moderate depression.Methods An open,single-arm,multi-center design was adopted in our study.Adult patients with mild and moderate depression who had received acute treatment of Morinda officinalis oligosaccharides were enrolled and continue to receive Morinda officinalis oligosaccharides capsules for 24 weeks,the dose remained unchanged during continuation treatment.The remission rate,recurrence rate,recurrence time,and the change from baseline to endpoint of Hamilton Depression Scale(HAMD),Hamilton Anxiety Scale(HAMA),Clinical Global Impression-Severity(CGI-S)and Arizona Sexual Experience Scale(ASEX)were evaluated.The incidence of treatment-related adverse events was reported.Results The scores of HAMD-17 at baseline and after treatment were 6.60±1.87 and 5.85±4.18,scores of HAMA were 6.36±3.02 and 4.93±3.09,scores of CGI-S were 1.49±0.56 and 1.29±0.81,scores of ASEX were 15.92±4.72 and 15.57±5.26,with significant difference(P＜0.05).After continuation treatment,the remission rate was 54.59％(202 cases/370 cases),and the recurrence rate was 6.49％(24 cases/370 cases),the recurrence time was(64.67±42.47)days.The incidence of treatment-related adverse events was 15.35％(64 cases/417 cases).Conclusion Morinda officinalis oligosaccharides capsules can be effectively used for the continuation treatment of mild and moderate depression,and are well tolerated and safe.

Objective:To construct a novel chimeric antigen receptor T (CAR-T) cell targeting CD138 and to investigate its cytotoxicity against myeloma cells.Methods:The hybridoma strain that can stably secrete the CD138 monoclonal antibody (mAb) was prepared and obtained through monoclonal antibody screening technology. The hybridoma strain cells were intraperitoneally injected into mice to produce ascites containing monoclonal antibodies, which were then collected and purified to obtain pure CD138 mAb. Further examinations were performed to assess the biological characteristics of CD138 mAb. The variable region sequence of this antibody was amplified through reverse transcription polymerase chain reaction and was used as the antigen recognition domain of CD138 CAR, which was subsequently expressed on the surface of T cells by lentiviral infection. Flow cytometry was employed to assess the phenotype of CD138 CAR-T cells. In vitro cytotoxicity and degranulation assays were performed to evaluate their antitumor effects.Results:① We successfully prepared anti-human CD138 antibody hybridoma cell lines and screened a hybridoma cell strain, 5G2, which could persistently and stably secrete the anti-CD138 antibody. ② The purified CD138 (5G2) mAb can especially recognize CD138 + cells with a binding affinity constant (K D) of 6.011×10 -9 mol/L and showed no significant binding activity with CD138 - cells. ③The variable region sequence of the CD138 (5G2) antibody was obtained using molecular cloning technology, and CD138 (5G2) CAR was successfully constructed and expressed on T cells through lentivirus infection and, concurrently, demonstrated effective binding to recombinant human CD138 protein.④ The proliferation of T cells transduced with the CD138 (5G2) CAR was highly efficient. The phenotype analysis revealed that CD138 (5G2) CAR-T cells exhibited a greater tendency to differentiate into central memory T cells and memory stem T cells, with a reduced proportion of terminally differentiated effector memory subsets. ⑤CD138 (5G2) CAR-T cells demonstrated specific cytotoxicity against CD138 + myeloma cell line H929, whereas CD138 - cell line K562 remained unaffected. The percentage of residual H929 cells was (12.92±8.02) % after co-culturing with CD138 (5G2) CAR-T cells, while (54.25±15.79) % was left in the Vector-T group (E∶T=1∶2; P<0.001). ⑥Results of degranulation assays demonstrated a significant activation of CD138 (5G2) CAR-T cells after co-culture with the H929 cell line, whereas no significant activation was observed in Vector-T cells [ (25.78±3.35) % vs (6.13±1.30) %, P<0.001]. ⑦After co-culturing with CD138 + cells, CD138 (5G2) CAR-T cells exhibited a significant increase in cytokine secretion compared to the Vector-T group [interleukin-2: (1 697.52±599.05) pg/ml vs (5.07±1.17) pg/ml, P<0.001; interferon-γ: (3 312.20±486.38) pg/ml vs (9.28±1.46) pg/ml, P<0.001; and tumor necrosis factor-α: (1 837.43±640.49) pg/ml vs (8.75±1.65) pg/ml, P<0.001]. However, no significant difference was observed in cytokine secretion levels between the two groups after co-culturing with CD138 - cells. Conclusion:This study successfully prepared a novel monoclonal antibody against CD138, and CAR-T cells constructed with the antigen recognition domain derived from this 5G2 mAb demonstrated effective antitumor activity against myeloma cells. This can be used as a new option for the detection of the CD138 antigen and proposes a novel strategy for multiple myeloma immunotherapy.

Background::There is a need for effective and safe therapies for psoriasis that provide sustained benefits. The aim of this study was to assess the efficacy and safety of tildrakizumab, an anti-interleukin-23p19 monoclonal antibody, for treating moderate-to-severe plaque psoriasis in Chinese patients.Methods::In this multi-center, double-blind, phase III trial, patients with moderate-to-severe plaque psoriasis were enrolled and randomly assigned (1:1) to receive subcutaneous tildrakizumab 100 mg or placebo at weeks 0 and 4. Patients initially assigned to placebo were switched to receive tildrakizumab at weeks 12, 16, and every 12 weeks thereafter. Patients in the tildrakizumab group continued with tildrakizumab at week 16, and every 12 weeks until week 52. The primary endpoint was the Psoriasis Area and Severity Index (PASI 75) response rate at week 12.Results::At week 12, tildrakizumab demonstrated significantly higher PASI 75 response rates (66.4% [73/110] vs. 12.7% [14/110]; difference, 51.4% [95% confidence interval (CI), 40.72, 62.13]; P <0.001) and Physician’s Global Assessment (60.9% [67/110] vs. 10.0% [11/110]; difference, 49.1% [95% CI, 38.64, 59.62]; P <0.001) compared to placebo. PASI 75 response continued to improve over time in both tildrakizumab and placebo-switching to tildrakizumab groups, reaching maximal efficacy after 28 weeks (86.8% [92/106] vs. 82.4% [89/108]) and maintained up to 52 weeks (91.3% [95/104] vs. 87.4% [90/103]). Most treatment-emergent adverse events were mild and not related to tildrakizumab. Conclusion::Tildrakizumab demonstrated durable efficacy through week 52 and was well tolerated in Chinese patients with moderate-to-severe plaque psoriasis.Trial registration::ClinicalTrials.gov, NCT05108766.

Cells are the fundamental structural and functional units of biological organisms,with inherent differences in composition and interactions with exogenous substances,known as cellular heterogeneity.Single cell inductively coupled plasma-mass spectrometry(SC-ICP-MS)allows for the high-throughput introduction of individual cells,enabling the highly sensitive detection and quantification of elements within a single cell,thus effectively providing information on cellular heterogeneity.This review outlined the SC-ICP-MS sample preparation process for different types of cells(single-cell systems,aggregation-prone and adherent cell systems,animal tissues,and plant tissues),including steps such as separation,washing,and fixation,as well as the advantages and existing issues of the current sample introduction systems and quantification methods.The recent applications of SC-ICP-MS in detecting endogenous substances(endogenous elements and proteins),exogenous substances(heavy metals,metal-based drugs and nanoparticles),and the simultaneous detection of both endogenous and exogenous substances were summarized.Finally,the perspectives on the future development of SC-ICP-MS in analytical methods and application fields were presented,including the optimization of single-cell sample preparation,transport efficiency,evaluation standards of ionization efficiency,and the establishment of multiparametric cell analysis platforms.

Objective To investigate the application value of combining the Demirjian's method with ma-chine learning algorithms for dental age estimation in northern Chinese Han children and adolescents.Methods Oral panoramic images of 10 256 Han individuals aged 5 to 24 years in northern China were collected.The development of eight permanent teeth in the left mandibular was classified into different stages using the Demirjian's method.Various machine learning algorithms,including support vector re-gression(SVR),gradient boosting regression(GBR),linear regression(LR),random forest regression(RFR),and decision tree regression(DTR)were employed.Age estimation models were constructed based on total,female,and male samples respectively using these algorithms.The fitting performance of different machine learning algorithms in these three groups was evaluated.Results SVR demonstrated superior estimation efficiency among all machine learning models in both total and female samples,while GBR showed the best performance in male samples.The mean absolute error(MAE)of the op-timal age estimation model was 1.246 3,1.281 8 and 1.153 8 years in the total,female and male samples,respectively.The optimal age estimation model exhibited varying levels of accuracy across dif-ferent age ranges,which provided relatively accurate age estimations in individuals under 18 years old.Conclusion The machine learning model developed in this study exhibits good age estimation effi-ciency in northern Chinese Han children and adolescents.However,its performance is not ideal when applied to adult population.To improve the accuracy in age estimation,the other variables can be con-sidered.

Objective To investigate the clinical characteristics and prognosis of pneumococcal meningitis(PM),and drug sensitivity of Streptococcus pneumoniae(SP)isolates in Chinese children.Methods A retrospective analysis was conducted on clinical information,laboratory data,and microbiological data of 160 hospitalized children under 15 years old with PM from January 2019 to December 2020 in 33 tertiary hospitals across the country.Results Among the 160 children with PM,there were 103 males and 57 females.The age ranged from 15 days to 15 years,with 109 cases(68.1% )aged 3 months to under 3 years.SP strains were isolated from 95 cases(59.4% )in cerebrospinal fluid cultures and from 57 cases(35.6% )in blood cultures.The positive rates of SP detection by cerebrospinal fluid metagenomic next-generation sequencing and cerebrospinal fluid SP antigen testing were 40% (35/87)and 27% (21/78),respectively.Fifty-five cases(34.4% )had one or more risk factors for purulent meningitis,113 cases(70.6% )had one or more extra-cranial infectious foci,and 18 cases(11.3% )had underlying diseases.The most common clinical symptoms were fever(147 cases,91.9% ),followed by lethargy(98 cases,61.3% )and vomiting(61 cases,38.1% ).Sixty-nine cases(43.1% )experienced intracranial complications during hospitalization,with subdural effusion and/or empyema being the most common complication[43 cases(26.9% )],followed by hydrocephalus in 24 cases(15.0% ),brain abscess in 23 cases(14.4% ),and cerebral hemorrhage in 8 cases(5.0% ).Subdural effusion and/or empyema and hydrocephalus mainly occurred in children under 1 year old,with rates of 91% (39/43)and 83% (20/24),respectively.SP strains exhibited complete sensitivity to vancomycin(100% ,75/75),linezolid(100% ,56/56),and meropenem(100% ,6/6).High sensitivity rates were also observed for levofloxacin(81% ,22/27),moxifloxacin(82% ,14/17),rifampicin(96% ,25/26),and chloramphenicol(91% ,21/23).However,low sensitivity rates were found for penicillin(16% ,11/68)and clindamycin(6% ,1/17),and SP strains were completely resistant to erythromycin(100% ,31/31).The rates of discharge with cure and improvement were 22.5% (36/160)and 66.2% (106/160),respectively,while 18 cases(11.3% )had adverse outcomes.Conclusions Pediatric PM is more common in children aged 3 months to under 3 years.Intracranial complications are more frequently observed in children under 1 year old.Fever is the most common clinical manifestation of PM,and subdural effusion/emphysema and hydrocephalus are the most frequent complications.Non-culture detection methods for cerebrospinal fluid can improve pathogen detection rates.Adverse outcomes can be noted in more than 10% of PM cases.SP strains are high sensitivity to vancomycin,linezolid,meropenem,levofloxacin,moxifloxacin,rifampicin,and chloramphenicol.[Chinese Journal of Contemporary Pediatrics,2024,26(2):131-138]

A 5-year-old girl was admitted due to one episode of melena and one episode of hematemesis.Upon admission,gastroscopy revealed esophageal and gastric varices.Abdominal CT scan,MRI,and color Doppler ultrasound suggested cirrhosis,intrahepatic bile duct dilation,and bilateral kidney enlargement.Genetic testing identified compound heterozygous mutations in the PKHD1 gene:c.2264C>T(p.Pro755Leu)and c.1886T>C(p.Val629Ala).The c.2264C>T(p.Pro755Leu)mutation is a known pathogenic variant with previous reports,while c.1886T>C(p.Val629Ala)is a novel mutation predicted to have pathogenic potential according to Mutation Taster and PolyPhen2.The child was diagnosed with autosomal recessive polycystic kidney disease.In children presenting with gastrointestinal bleeding without obvious causes,particularly those with liver or kidney disease,consideration should be given to the possibility of autosomal recessive polycystic kidney disease,and genetic testing should be conducted for definitive diagnosis when necessary.