ObjectiveTo compare the histological staining performance of four various tissue fixatives, including a self-developed fixative, for preparing paraffin sections of rat eyeball tissue. MethodsTwenty 5-week-old male Sprague-Dawley (SD) rats were randomly divided into 4 groups (n=5 per group). After anesthesia by intraperitoneal injection of Zoletil™ 50 at a dose of 45 mg/kg body weight, the rats were euthanized by exsanguination via the abdominal aorta. Bilateral eyeballs were carefully extracted intact and fixed for 72 h in 10% formaldehyde fixative, glutaraldehyde-formaldehyde mixed fixative, Davidson's fixative, and self-developed fixative, respectively. After fixation, the eyeballs were longitudinally sectioned along the optic nerve, with the portions containing the optic nerve preserved. The tissues were then dehydrated, embedded, and sectioned. Following hematoxylin and eosin (HE) staining, histological staining quality was compared among ocular structures including the cornea, lens, and retina. ResultsThe overall appearance of rat eyeballs showed marked shrinkage in the 10% formaldehyde group and the glutaraldehyde-formaldehyde group, whereas the eye morphology remained round and intact in the modified Davidson's fixative group and self-developed fixative group. The corneal stroma exhibited obvious rupture, and the cells were arranged in folded arrangement in the modified Davidson's fixative group, 10% formaldehyde group, and self-developed fixative group. In contrast, the corneal cells in the glutaraldehyde-formaldehyde group were neatly arranged, showing no rupture or folding, and exhibited clear staining, indicating the highest quality of corneal sectioning among all groups. In the 10% formaldehyde group, cracks were observed in the equatorial and cortical regions of the lens, but the lens fiber structure remained intact. The lenses in the modified Davidson's fixative group showed extensive rupture and detachment. The glutaraldehyde-formaldehyde group displayed only slight cracks at the equator. In the self-developed fixative group, mild red folding was limited to the peripheral lens region, with the remaining structures intact and unbroken. These findings indicated that the glutaraldehyde-formaldehyde and self-developed fixative groups achieved the best lens sectioning quality. The retina was severely detached from the choroid/sclera layer, with extensive rupture of each cellular layer in the 10% formaldehyde fixative group. In the glutaraldehyde-formaldehyde group, partial detachment between the retina and choroid/sclera was observed. The outer plexiform layer and nerve fiber layer showed separation with edema, while the cells in all layers were neatly arranged. In both the Davidson's fixative and the self-developed fixative groups, the retina remained intact without rupture, and no structural separation was observed in any layer. Both demonstrated advantages in preserving the integrity and orderly arrangement of all retinal layers; however, the self-developed fixative group exhibited greater contrast. ConclusionThe choice of fixative significantly affects the morphological preservation of various structures in the rat eye. The self-developed fixative demonstrates the best overall performance in maintaining overall eye morphology, the structural integrity of the lens, and retinal adhesion. For studies focusing solely on the corneal structure, the glutaraldehyde-formaldehyde mixed fixative is recommended. The 10% formaldehyde fixative exhibits unsatisfactory fixation effects for all the aforementioned ocular structures and is not recommended for detailed morphological studies of eyeball tissues.

Objective To investigate the prognostic value of remnant lipoprotein cholesterol(RLP-C)and platelet-lymphocyte ratio(PLR)for elderly patients with acute myocardial infarction(AMI)stratified by body mass index(BMI).Methods A total of 130 elderly AMI patients admitted to our hospital from January 2022 to January 2024 were recruited,and then based on their BMI,they were categorized into low(n=18),normal(n=60),and high BMI groups(n=52).Multivariate logistic regression analysis was used to identify the risk factors for poor prognosis in elderly AMI patients.Spearman correlation analysis was conducted to examine the relationship of RLP-C and PLR with prognostic outcomes.ROC curve analysis was performed to evaluate the predictive per-formance of the two indicators for prognosis in elderly AMI patients of different BMI.Results Significant differences in RLP-C and PLR levels were observed among the above three groups(P＜0.05,P＜0.01).In the overall population,as well as in the low,normal and high BMI groups,both RLP-C and PLR were positively correlated with adverse outcomes in elderly AMI patients(P＜0.01).PLR and RLP-C were independent risk factors for poor prognosis in elderly AMI pa-tients(P＜0.01),and they were independently associated with prognosis in each BMI group(P＜0.01).The combined the three indicators together significantly improved the sensitivity and speci-ficity in predicting adverse outcomes in elderly AMI patients when compared to single indicator alone(sensitivity:54.29％,75.94％,64.18％vs 82.61％;specificity:68.83％,70.22％,72.15％vs 80.49％;P＜0.01).Conclusion RLP-C and PLR are influencing factors for poor prognosis in eld-erly AMI patients,and can serve as predictive factors for prognosis,which are helpful for provi-ding valuable guidance for early treatment and prevention of adverse outcomes.

Objective To investigate the role and mechanism of AMP-activated protein kinase(AMPK)in regulating mitochondrial function and cardiomyocyte injury in sepsis.Methods Forty Balb/c mice were randomly divided into four groups:Sham group(n=10),Sham+5-aminoimidazole-4-carboxamide ribonucleotide(AICAR)group(n=10),CLP group(n=10),and CLP+AICAR group(n=10).A sepsis mouse model was established through cecal ligation and puncture(CLP).Echocardiography and histological analysis were used to assess sepsis-induced cardiac injury.Neonatal rat cardiomyocytes(NRCMs)were incubated with lipopolysaccharide(LPS)(10 μg/mL)for 24 h to induce an in vitro sepsis model,and treated with AICAR.Mitochondrial function and dynamics were assessed by using Western blotting,enzyme-linked immunosorbent assay(ELISA),and immunofluorescence assays.Results Compared with the Sham group,AMPK expression in the myocardial tissue of CLP mice was significantly reduced(P<0.05).Compared with the CLP group,AMPK expression in the CLP+AICAR group was significantly increased(P<0.05).Survival analysis showed that CLP led to a high mortality rate(～60％ ),while AICAR treatment significantly improved the survival rate of CLP mice(P<0.05).Compared with the Sham group,cardiac output(CO),stroke volume(SV),and left ventricular end-diastolic volume(LVEDV)were significantly decreased in the CLP group(P<0.05),while left ventricular posterior wall systolic(LVPWs)and left ventricular posterior wall thickness(LVPWd)were significantly increased(P<0.05).AICAR treatment alleviated the cardiac dysfunction induced by CLP.Compared with the CLP group,mitochondrial size and the number of mitochondrial cristae in the myocardial tissue of CLP+AICAR group mice were significantly increased(P<0.05),while DHE fluorescence intensity and the number of TUNEL-positive cells were significantly reduced(P<0.05).Compared with the LPS group,ATP production,mitochondrial respiration rate,and complex Ⅰ,Ⅱ,and Ⅲ activities in NRCMs of the LPS+AICAR group were significantly increased(P<0.05),while mitochondrial and cytoplasmic ROS levels were significantly reduced(P<0.05).Compared with the control group,mitochondrial size in NRCMs of the LPS group was significantly reduced(P<0.05),while Bax and Caspase-3 expression,as well as mitochondrial fission index,were significantly increased(P<0.05),and these changes were mitigated by AICAR(P<0.05).Conclusion AMPK plays a crucial role in maintaining cardiac function and mitigating septic myocardial injury by regulating mitochondrial structure and function,energy metabolism,oxidative stress,and apoptosis.

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 explore the effect of 3D printing auxiliary stent on the operation of laryngeal microsurgery instrument.Methods Auxiliary stent of suspension laryngoscope was design and 3D printed.30 standardized training residents as experimental participants were randomly divided into conventional group and auxiliary stent group(15 in each group).The pig's larynx was used as a specimen,and the vocal folds were marked with localized staining.Participants performed operation on the stained areas of the vocal folds under suspension laryngoscope(60 times of grasping in 1 h).The conventional group performed operation unaided;The auxiliary stent group performed operation with the auxiliary stent as a support.Two senior chief physicians scored the participants'stability and accuracy.Results The operational stability scale score of the conventional group and the auxiliary stent group were(5.03±4.33)and(8.99±3.42),respectively;The operation accuracy rates were 58.4%(526/900)and 78.9%(710/900),respectively.The operation accuracy rate,operation stability of the auxiliary stent group were significantly higher than those in the conventional group,and the differences were significant(P<0.01).Conclusion The auxiliary stent can significantly improve the stability and accuracy of operation,which has highly application value.

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 establish a rapid immunological detection method for MPT64 protein based on red microspheres and select highly-sensitive and highly-specific antibody pairs.Methods A His-tagged prokaryotic expression vector was constructed for expression of MPT64 protein that was used to immunize New Zealand white rabbits after purification and validation.Peripheral blood mononuclear cells(PBMCs)were isolated from the rabbits,and antigen-specific B cells expressing antibodies were sorted using single B-cell flow cytometry.mRNA in B cells was reverse-transcribed into cDNA,and paired antibody heavy-and light-chain sequences were amplified via nested PCR.Expression vectors were constructed,and recombinant antibodies were produced in Expi293F cells.Fluorescent immunochromatography was employed to screen for matched antibody pairs.The selected antibodies were used to establish a rapid detection method based on red microsphere immunochromatography.Results Ten high-affinity monoclonal antibodies against MPT64 were generated.Two antibody pairs were selected for MPT64 immunodetection that reached a sensitivity of 0.0125 ng/mL.Conclusion High-affinity rabbit monoclonal antibodies against MPT64 are obtained via single B-cell technology,and a rapid red microspheres-based immunodetection method is established,enabling highly sensitive detection of Mycobacterium tuberculosis MPT64 protein.

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.