Objective To explore the effects of different concentrations of simvastatin on nerve regeneration after sciatic nerve injury.Methods Rats were randomly divided into the normal group,the control group,the low-dose group and the high-dose group,with 3 rats in each group.Except for the normal group,adult rat sciatic nerve crush injury models were established in the other groups.Rats in the normal group and the control group were orally administered with water,while those in the low-dose group and high-dose group were orally administered with 98%simvastatin at dosages of 4 mg/mL and 40 mg/mL,respectively.The sciatic nerve regeneration in rats was evaluated by sciatic function index(SFI),HE staining,luxol fast blue(LFB)staining and immunofluorescence staining,etc.Results The SFI of rats in the high-dose group 7 days and 14 days after surgery were higher than those in the control group(P<0.05);there was no significant difference in SFI of rats between the low-dose group and the control group 7 days and 14 days after surgery(P>0.05).HE staining and LFB staining results showed that compared with the control group,the number of neurons of rats in the high-dose group increased,the nerve fibers and myelin were clearer and denser,and the nerve function was significantly restored;while no significant improvement was observed in the sciatic nerve of rats in the low-dose group.The immunofluorescence staining results showed that compared with the control group,the immunofluorescence intensity in the high-dose group increased,while that in the low-dose group decreased,the differences were statistically significant(P<0.05).Conclusion High-dose simvastatin can promote peripheral nerve regeneration by regulating the expression of M2 macrophages.

Objective To examine the changing prevalence and antimicrobial resistance profiles of Burkholderia cepacia in 52 hospitals across China from 2015 to 2021.Methods A total of 9 261 strains of B.cepacia were collected from 52 hospitals between January 1,2015 and December 31,2021.Antimicrobial susceptibility of the strains was tested using Kirby-Bauer method or automated antimicrobial susceptibility testing systems according to a unified protocol.The results were interpreted according to the breakpoints released in the Clinical & Laboratory Standards Institute(CLSI)guidelines(2023 edition).Results A total of 9 261 strains of B.cepacia were isolated from all age groups,especially elderly patients.The proportion was 11.1％(1 032 strains)in children,significantly lower than the proportion in adults.About half(46.5％,4 310/9 261)of the strains were isolated from patients at least 60 years old and 42.3％(3 919/9 261)of the strains were isolated from young adults.Most isolates(71.1％)were isolated from sputum and respiratory secretions,followed by urine(10.7％)and blood samples(8.1％).B.cepacia isolates were highly susceptible to the five antimicrobial agents recommended in the CLSI M100 document(33rd edition,2023).B.cepacia isolates showed relatively higher resistance rates to meropenem and levofloxacin.However,the resistance rates to ceftazidime,trimethoprim-sulfamethoxazole,and minocycline remained below 8.1％.The percentage of B.cepacia strains resistant to levofloxacin was the highest compared to other antibiotics in any of the three age groups(from 12.4％in the patients＜18 years old to 20.6％in the patients aged 60 years or older).Conclusions B.cepacia is one of the clinically important non-fermenting gram-negative bacteria.Accurate and timely reporting of antimicrobial susceptibility test results and ongoing antimicrobial resistance surveillance are helpful for rational prescription of antimicrobial agents and proper prevention and control of nosocomial infections.

Objective To propose an EBT3 film technology-based quality control measurement method for the INTRABEAM PRS500 intraoperative radiotherapy equipment to solve the problems of the traditional methods in cumbersome operation and setup error.Methods According to HJ 1198-2021 Requirements of radiation safety and protection for radiotherapy and GBZ 121-2020 Requirements for radiological protection in radiotherapy,the environmental radiation testing of the INTRABEAM PRS500 intraoperative radiotherapy equipment was carried out point by point by means of the radiation inspection instrument.The INTRABEAM PRS500 intraoperative radiotherapy equipment was characterized by a point X-ray source(XRS),and the XRS was detected in terms of the probe linearity,radiation dose,dynamic deviation,isotropy and dose rate.The EBT3 film technology was used to verify the symmetry and isotropy of the XRS planar dose of INTRABEAM PRS500 intraoperative radiotherapy equipment.Results The X-γ dose equivalent rate of each monitoring site of the INTRABEAM PRS500 intraoperative radiotherapy device was lower than the method detection limit(MDL).The results of SQA quality control showed that the INTRABEAM PRS500 intraoperative radiotherapy equipment XRS met the quality control requirements in terms of the probe linearity,radiation dose,dynamic deviation and etc,and the isotropy differences in the+X,-X,+Y,and-Y axis directions ranged from-1.40％to 1.79％,which were all within the allowable range of measurement tolerance(5.60％to 5.65％).The results of measuring the isotropy of the INTRABEAM PRS500 intraoperative radiotherapy equipment based on the EBT3 film technology showed that the dose distribution of the XRS in the directions of the+X,-X,+Y,and-Y axes at the same plane was well isotropic,and that the doses in the directions of the X and Y axes were symmetrically distributed,and that the maximum skewness value for the isotropy of the XRS in the XY plane was-1.581％,which met the requirements of AAPM TG61 report on the reference dosimetry of low-energy and medium-energy X-rays for radiotherapy and radiobiology of≤±5.3％.Conclusion The EBT3 film technology-based measurement method gains high simplicity and feasibility for the isotropy of the INTRABEAM PRS500 intraoperative radiotherapy equipment in the directions of the+X,-X,+Y,and-Y axes at the same planet,which realizes the dynamic monitoring of the dosimetric changes and facilitates the whole-process quality control management of the intraoperative radiotherapy equipment.[Chinese Medical Equipment Journal,2025,46(6):47-53]

Objective To investigate the distribution and antimicrobial resistance profiles of common pathogens isolated from cerebrospinal fluid(CSF)in CHINET program from 2015 to 2021.Methods The bacterial strains isolated from CSF were identified in accordance with clinical microbiology practice standards.Antimicrobial susceptibility test was conducted using Kirby-Bauer method and automated systems per the unified CHINET protocol.Results A total of 14 014 bacterial strains were isolated from CSF samples from 2015 to 2021,including the strains isolated from inpatients(95.3％)and from outpatient and emergency care patients(4.7％).Overall,19.6％of the isolates were from children and 80.4％were from adults.Gram-positive and Gram-negative bacteria accounted for 68.0％and 32.0％,respectively.Coagulase negative Staphylococcus accounted for 73.0％of the total Gram-positive bacterial isolates.The prevalence of MRSA was 38.2％in children and 45.6％in adults.The prevalence of MRCNS was 67.6％in adults and 69.5％in children.A small number of vancomycin-resistant Enterococcus faecium(2.2％)and linezolid-resistant Enterococcus faecalis(3.1％)were isolated from adult patients.The resistance rates of Escherichia coli and Klebsiella pneumoniae to ceftriaxone were 52.2％and 76.4％in children,70.5％and 63.5％in adults.The prevalence of carbapenem-resistant E.coli and K.pneumoniae(CRKP)was 1.3％and 47.7％in children,6.4％and 47.9％in adults.The prevalence of carbapenem-resistant Acinetobacter baumannii(CRAB)and Pseudomonas aeruginosa(CRPA)was 74.0％and 37.1％in children,81.7％and 39.9％in adults.Conclusions The data derived from antimicrobial resistance surveillance are crucial for clinicians to make evidence-based decisions regarding antibiotic therapy.Attention should be paid to the Gram-negative bacteria,especially CRKP and CRAB in central nervous system(CNS)infections.Ongoing antimicrobial resistance surveillance is helpful for optimizing antibiotic use in CNS infections.

Objective To investigate the antimicrobial resistance of clinical isolates from elderly patients(≥65 years)in major medical institutions across China.Methods Bacterial strains were isolated from elderly patients in 52 hospitals participating in the CHINET Antimicrobial Resistance Surveillance Program during the period from 2015 to 2021.Antimicrobial susceptibility test was carried out by disk diffusion method and automated systems according to the same CHINET protocol.The data were interpreted in accordance with the breakpoints recommended by the Clinical and Laboratory Standards Institute(CLSI)in 2021.Results A total of 514 715 nonduplicate clinical isolates were collected from elderly patients in 52 hospitals from January 1,2015 to December 31,2021.The number of isolates accounted for 34.3％of the total number of clinical isolates from all patients.Overall,21.8％of the 514 715 strains were gram-positive bacteria,and 78.2％were gram-negative bacteria.Majority(90.9％)of the strains were isolated from inpatients.About 42.9％of the strains were isolated from respiratory specimens,and 22.9％were isolated from urine.More than half(60.7％)of the strains were isolated from male patients,and 39.3％isolated from females.About 51.1％of the strains were isolated from patients aged 65-＜75 years.The prevalence of methicillin-resistant strains(MRSA)was 38.8％in 32 190 strains of Staphylococcus aureus.No vancomycin-or linezolid-resistant strains were found.The resistance rate of E.faecalis to most antibiotics was significantly lower than that of Enterococcus faecium,but a few vancomycin-resistant strains(0.2％,1.5％)and linezolid-resistant strains(3.4％,0.3％)were found in E.faecalis and E.faecium.The prevalence of penicillin-susceptible S.pneumoniae(PSSP),penicillin-intermediate S.pneumoniae(PISP),and penicillin-resistant S.pneumoniae(PRSP)was 94.3％,4.0％,and 1.7％in nonmeningitis S.pneumoniae isolates.The resistance rates of Klebsiella spp.(Klebsiella pneumoniae 93.2％)to imipenem and meropenem were 20.9％and 22.3％,respectively.Other Enterobacterales species were highly sensitive to carbapenem antibiotics.Only 1.7％-7.8％of other Enterobacterales strains were resistant to carbapenems.The resistance rates of Acinetobacter spp.(Acinetobacter baumannii 90.6％)to imipenem and meropenem were 68.4％and 70.6％respectively,while 28.5％and 24.3％of P.aeruginosa strains were resistant to imipenem and meropenem,respectively.Conclusions The number of clinical isolates from elderly patients is increasing year by year,especially in the 65-＜75 age group.Respiratory tract isolates were more prevalent in male elderly patients,and urinary tract isolates were more prevalent in female elderly patients.Klebsiella isolates were increasingly resistant to multiple antimicrobial agents,especially carbapenems.Antimicrobial resistance surveillance is helpful for accurate empirical antimicrobial therapy in elderly patients.

Objective To analyze cases of Langerhans cell histiocytosis(LCH)initially presenting with hemophagocytic lymphohistiocytosis(HLH)in order to enhance clinicians'awareness and avoid misdiagnosis or missed diagnosis.Methods Clinical characteristics of two cases of LCH with HLH as the initial symptom cases were retrospectively collected and analyzed.Results Both patients were male and admitted with"fever and bicytopenia".The physical examination revealed scattered rashes and hepatosplenomegaly.Based on the laboratory results,HLH was initially considered in both children.In case 1,the underlying disease was not immediately identified,but a skin biopsy later confirmed LCH.The patient's symptoms improved with LCH-directed therapy;however,a secondary pulmonary infection triggered progressive hemophagocytosis,which was successfully controlled after adding HLH treatment.In Case 2,HLH treatment initially stabilized the fever.After a skin biopsy confirmed LCH,combined LCH therapy was administered,and the symptoms improved.Both patients received regular chemotherapy according to the CCHG-LCH-2019 protocol.During follow-up,Case 1 developed a BRAF gene mutation and was treated with oral trametinib in addition to chemotherapy.As of the latest follow-up,both patients remained in stable condition.Conclusion Children with HLH and accompanied by a rash should actively search for the underlying cause.A skin biopsy should be performed promptly to clarify the diagnosis.Once the diagnosis is confirmed,active treatment is necessary,a single treatment approach should be avoided,and timely assessment of the condition should be conducted to achieve personalized treatment.

Objective To examine the changing prevalence and antimicrobial resistance profiles of Burkholderia cepacia in 52 hospitals across China from 2015 to 2021.Methods A total of 9 261 strains of B.cepacia were collected from 52 hospitals between January 1,2015 and December 31,2021.Antimicrobial susceptibility of the strains was tested using Kirby-Bauer method or automated antimicrobial susceptibility testing systems according to a unified protocol.The results were interpreted according to the breakpoints released in the Clinical & Laboratory Standards Institute(CLSI)guidelines(2023 edition).Results A total of 9 261 strains of B.cepacia were isolated from all age groups,especially elderly patients.The proportion was 11.1％(1 032 strains)in children,significantly lower than the proportion in adults.About half(46.5％,4 310/9 261)of the strains were isolated from patients at least 60 years old and 42.3％(3 919/9 261)of the strains were isolated from young adults.Most isolates(71.1％)were isolated from sputum and respiratory secretions,followed by urine(10.7％)and blood samples(8.1％).B.cepacia isolates were highly susceptible to the five antimicrobial agents recommended in the CLSI M100 document(33rd edition,2023).B.cepacia isolates showed relatively higher resistance rates to meropenem and levofloxacin.However,the resistance rates to ceftazidime,trimethoprim-sulfamethoxazole,and minocycline remained below 8.1％.The percentage of B.cepacia strains resistant to levofloxacin was the highest compared to other antibiotics in any of the three age groups(from 12.4％in the patients＜18 years old to 20.6％in the patients aged 60 years or older).Conclusions B.cepacia is one of the clinically important non-fermenting gram-negative bacteria.Accurate and timely reporting of antimicrobial susceptibility test results and ongoing antimicrobial resistance surveillance are helpful for rational prescription of antimicrobial agents and proper prevention and control of nosocomial infections.

Objective To summarize the changing prevalence of carbapenem resistance in Enterobacterales based on the data of CHINET Antimicrobial Resistance Surveillance Program from 2015 to 2021 for improving antimicrobial treatment in clinical practice.Methods Antimicrobial susceptibility testing was performed using a commercial automated susceptibility testing system according to the unified CHINET protocol.The results were interpreted according to the breakpoints of the Clinical & Laboratory Standards Institute(CLSI)M100 31st ed in 2021.Results Over the seven-year period(2015-2021),the overall prevalence of carbapenem-resistant Enterobacterales(CRE)was 9.43％(62 342/661 235).The prevalence of CRE strains in Klebsiella pneumoniae,Citrobacter freundii,and Enterobacter cloacae was 22.38％,9.73％,and 8.47％,respectively.The prevalence of CRE strains in Escherichia coli was 1.99％.A few CRE strains were also identified in Salmonella and Shigella.The CRE strains were mainly isolated from respiratory specimens(44.23±2.80)％,followed by blood(20.88±3.40)％and urine(18.40±3.45)％.Intensive care units(ICUs)were the major source of the CRE strains(27.43±5.20)％.CRE strains were resistant to all the β-lactam antibiotics tested and most non-β-lactam antimicrobial agents.The CRE strains were relatively susceptible to tigecycline and polymyxins with low resistance rates.Conclusions The prevalence of CRE strains was increasing from 2015 to 2021.CRE strains were highly resistant to most of the antibacterial drugs used in clinical practice.Clinicians should prescribe antimicrobial agents rationally.Hospitals should strengthen antibiotic stewardship in key clinical settings such as ICUs,and take effective infection control measures to curb CRE outbreak and epidemic in hospitals.

Objective To characterize the changing species distribution and antibiotic resistance profiles of respiratory isolates in hospitals participating in the CHINET Antimicrobial Resistance Surveillance Program from 2015 to 2021.Methods Commercial automated antimicrobial susceptibility testing systems and disk diffusion method were used to test the susceptibility of respiratory bacterial isolates to antimicrobial agents following the standardized technical protocol established by the CHINET program.Results A total of 589 746 respiratory isolates were collected from 2015 to 2021.Overall,82.6％of the isolates were Gram-negative bacteria and 17.4％were Gram-positive bacteria.The bacterial isolates from outpatients and inpatients accounted for(6.0±0.9)％and(94.0±0.1)％,respectively.The top microorganisms were Klebsiella spp.,Acinetobacter spp.,Pseudomonas aeruginosa,Staphylococcus aureus,Haemophilus spp.,Stenotrophomonas maltophilia,Escherichia coli,and Streptococcus pneumoniae.Each microorganism was isolated from significantly more males than from females(P＜0.05).The overall prevalence of methicillin-resistant S.aureus(MRSA)was 39.9％.The prevalence of penicillin-resistant S.pneumoniae was 1.4％.The prevalence of extended-spectrum β-lactamase(ESBL)-producing E.coli and K.pneumoniae was 67.8％and 41.3％,respectively.The overall prevalence of carbapenem-resistant E.coli,K.pneumoniae,Enterobacter cloacae,Pseudomonas aeruginosa,and Acinetobacter baumannii was 3.7％,20.8％,9.4％,29.8％,and 73.3％,respectively.The prevalence of β-lactamase was 96.1％in Moraxella catarrhalis and 60.0％in Haemophilus influenzae.The H.influenzae isolates from children(＜18 years)showed significantly higher resistance rates to β-lactam antibiotics than the isolates from adults(P＜0.05).Conclusions Gram-negative bacteria are still predominant in respiratory isolates associated with serious antibiotic resistance.Antimicrobial resistance surveillance should be strengthened in clinical practice to support accurate etiological diagnosis and appropriate antimicrobial therapy based on antimicrobial susceptibility testing results.

Objective:To investigate the effects of circular RNA(circRNA)hsa_circ_0081621 on the malignant biological behaviors of human laryngeal squamous cell carcinoma AMC-HN-8 and TU177 cells.Methods:AMC-HN-8 and TU177 cells were routinely cultured.si-NC,si-hsa_circ_0081621,empty vector(vector),and hsa_circ_0081621 overexpression vector(hsa_circ_0081621-OE)were transfected into AMC-HN-8 and TU177 cells,namely si-NC,si-hsa_circ_0081621,vector,and hsa_circ_0081621-OE groups,respectively.The effects of knockdown or overexpression of hsa_circ_0081621 on the proliferation,migration,and invasion of AMC-HN-8 and TU177 cells were detected by CCK-8 assay,colony formation assay,scratch wound healing assay,and Transwell chamber assay.Results:Successful knockdown or overexpression of hsa_circ_0081621 was achieved in AMC-HN-8 and TU177 cells.hsa_circ_0081621 knockdown significantly inhibited while hsa_circ_0081621 overexpression significantly promoted the proliferation,migration,and invasion of AMC-HN-8 and TU177 cells(P<0.01 or P<0.001 or P<0.0001).Conclusion:hsa_circ_0081621 promotes the malignant biological behaviors of human laryngeal squamous cell carcinoma AMC-HN-8 and TU177 cells.