ObjectiveThis study explores the methods of lung tissue extraction and fixation required for pathological studies of fetal rats, based on the unique physiological structure of fetal rat lung tissue and existing lung tissue fixation techniques for adult rats. MethodsSix pregnant adult SD rats at 20.5 days of gestation were subjected to cesarean section to obtain fetal rats. Four healthy fetal rats with similar body weight, vital signs, and respiratory status were selected from each pregnant rat, and they were randomly divided into the following groups using a random number table: direct lung infiltration group, lung infiltration group after intratracheal infusion, whole-body infiltration group of fetal rats, and whole-body infiltration group after intratracheal infusion of fetal rats. To systematically compare and analyze the anatomical morphology under different fixation methods, lung tissues from four groups of fetal rats were harvested, perfused, and fixed, and the gross morphology of lung tissues in each group was observed. Paraffin sections were prepared and stained with Hematoxylin-Eosin (H&E). The histological morphology of the whole lung, alveoli, and bronchi was further examined under optical microscopy. ResultsIn the direct lung infiltration group, the hilar structures were unclear, lung lobation was indistinct, the shape was irregular, lung cavities were small, and alveoli and bronchi were shrunken. In the lung infiltration group after intratracheal infusion, the hilar structures were clear, lobation was pronounced, the shape was regular, lung cavities were large, and alveoli and bronchi were full. Both the whole-body infiltration group and whole-body infiltration group after intratracheal infusion of fetal rats exhibited visible lungs, hearts, skins, and other organs. The lung tissues of both groups showed obvious lobulation, irregular shape, and damage at the margins of lung lobes. In the whole-body infiltration group, the thoracic cavities of the fetus were flattened, lung cavities were small, and alveoli and bronchi were shrunken. In the whole-body infiltration group after intratracheal infusion of fetal rats, the fetal thoracic cavities were full, lung cavities were large, and alveoli and bronchi were relatively full. ConclusionThe lung infiltration after intratracheal infusion method for fetal rat lung tissue fixation outperforms direct lung infiltration, whole-body infiltration of fetal rats, and whole-body infiltration after intratracheal infusion of fetal rats in terms of preservation of the lung tissue's original morphology, paraffin sectioning, staining, and pathological observation and analysis. The embedding, sectioning, and staining processes are also simple and save consumables. Therefore, intratracheal infusion followed by lung infiltration method is recommended for fixation in histopathological observation of fetal rat lung tissue.

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.

Objective To explore the mechanism of electroacupuncture pretreatment(EP)for relieving post-stroke spasticity in rats.Methods Eighteen rats were randomized equally into sham-operated group,middle cerebral artery occlusion(MCAO)group,and MCAO+EP group.In MCAO+EP group,the rats received electroacupuncture at the acupoints Qubin and Baihui for 3 consecutive days prior to MCAO.Neurological deficits and cognitive function of the rats were evaluated,and pathologies in the hippocampus were examined using HE,Nissl,and TUNEL staining.The expressions of IL-4,IL-6,TNF-α,and TMAO in the brain tissues were detected with ELISA,and the mRNA and protein expression levels of NF-κB p65,NLRP3,caspase-3,and caspase-9 were determined with qRT-PCR,Western blotting,and immunohistochemistry.Results The rats receiving MCAO had significantly increased neurological deficit scores and showed increased muscle tension,number of apoptotic neurons,and expressions of IL-6,TNF-α,NF-κB p65,NLRP3,caspase-3 and caspase-9 in the hippocampus and significantly reduced length of time for new object recognition.Microscopically,the cells in the hippocampus of the MCAO rats showed uneven and loosened arrangement and unclear cell boundaries.In contrast,the rats in I/R+EP group showed significantly lowered neurological deficit scores and dystonia rating scores,reduced cell apoptosis,lowered hippocampal expressions of IL-6,TNF-α,caspase-3,caspase-9,and NF-κB p65,increased time for new object recognition,tightly arranged and uniformly stained hippocampal cells with clear boundaries,with also an increased number of active neurons and enhanced expression of IL-4 in the hippocampus.Conclusion EP alleviates post-stroke spasticity in rats by inhibiting inflammatory responses and hippocampal neuronal apoptosis mediated by the NF-κB/NLRP3 signaling pathway.

Objective To investigate disease characteristics and hospitalization costs of children with Mycoplasma Pneumoniae pneumonia(MPP)admitted to Shanghai municipal medical hospitals from 2019 to 2023.Methods Depending on the Shanghai Municipal Hospital Pediatric Alliance,we retrospectively investigated community acquired MPP pediatric patients hospitalized in 22 municipal hospitals with pediatric qualifications(including 4 children's hospitals)in Shanghai from Jan 2019 to Dec 2023.We collected the patients'diagnosis codes,gender,age,length of hospital stay,hospitalization costs,and whether they progressed to severe Mycoplasma pneumoniae pneumonia(SMPP).Results From 2019 to 2023,a total of 29 045 hospitalized children with MPP were treated,with 6 035 cases(20.8%)identified as SMPP in the 22 hospitals.Trend analysis revealed a rising trend with years in the proportion of SMPP patients(χ2trend=365.498,P<0.001).Among the 4 children's hospitals,there were 18 710 cases with MPP,including 4 078 cases(21.8%)of SMPP.The proportion of SMPP patients also showed an increasing trend with years(χ2trend=14.548,P<0.001),and the proportion in 2023(23.0%)was higher than that in previous years with statistical significance.There were statistical differences in the seasonal distribution of MPP cases between different years,with higher proportions in summer and autumn overall.The age distribution of hospitalized MPP children varied among different years,with school-age children accounting for the majority(56.8%)in 2023.There was no difference in the distribution of severe cases between different genders,but there were differences in the proportion of severe cases among different age groups in different years,with a gradual increase in severe cases among children aged 1 to 3 years(χ2trend=191.567,P<0.001).The average length of hospital stay for MPP during the epidemic was higher than that during non-epidemic periods,and there were statistically significant differences in the average length of hospital stay between different years(P<0.001).The individual hospitalization costs during the epidemic were higher than in other years,and there were statistically significant differences in individual hospitalization costs between different years(P<0.001).The total hospitalization costs were still higher in 2019 and 2023.The individual hospitalization costs for SMPP were higher than for non-SMPP cases.Conclusion MPP outbreaks occurred in Shanghai in 2019 and 2023,with the higher proportions in summer and autumn overall.Compared to previous years,the number of hospitalized MPP children in Shanghai was higher in 2023,with a higher proportion of SMPP cases,especially among children under 3 years old.The individual per capita hospitalization expenses for SMPP cases were higher than for non-SMPP cases.

For the past 30 years,percutaneous balloon mitral valve dilatation has been performed under the guidance of X-rays and bedside ultrasound.However,there are still some cases of mitral valve stenosis in the large atrium where balloon dilation failed.Intraperitoneal ultrasound-guided percutaneous balloon mitral valve plasty is accurate and feasible,which can reduce the occurrence of complications and improve the success rate of such elderly complex cases.Two patients with severe mitral stenosis underwent percutaneous balloon mitral valve plasty guided by intracardiac ultrasound.The operations were successful without any complications,which can provide reference for clinical treatment of mitral stenosis.

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]

Objective To construct the demand model of four types of medical resources including beds in hospi-tal,beds in intensive care unit(ICU),ventilators and medical human resources during the major infectious disease epidemic events,simulate and analyze the treatment of infectious diseases when different medical resources are in short supply.Methods Based on the susceptible-exposed-infectious-recovered(SEIR)model,considering the infec-tivity of infected persons,the susceptibility of the population and the immunity of convalescents,the characteristics of asymptomatic COVID-19 patients and different clinical types,the"COVID-19 infection-hospitalization model"was constructed.By collecting and setting the parameters of disease transmission,clinical course and medical re-source shortage scenarios,an analysis model of allocation and supply of urban medical resources during infectious di-sease epidemic events was initially formed based on Anylogic platform,the supply and demand of medical resources during infectious disease events in different scenarios were analyzed.Results In the non-intervention scenario,the peak time of bed demand was on the 107th day,and the peak value was 160.92 beds per thousand people;the peak time of ventilator demand was on the 122nd day,and the peak value was 5.61 units per thousand people;the peak time of ICU bed demand was on the 117th day,and the peak value was 12.78 beds per thousand people;the peak time of the demand for medical human resources was on the 109th day,and the peak value was 151.12 persons per thousand persons.The simulation results suggested that there were some differences in the impact of different medi-cal resources on the outcome of medical treatment.Conclusion This study constructs an analytical tool for the allo-cation and supply of urban medical resources under the epidemic events of infectious diseases,and the results of mul-tiple simulation experiments suggest that bed resources and medical human resources play more important roles in the outcome of medical treatment.

Objective:To investigate the distribution and primary drainage sites of the venous drainage system in the pedicled nasal septal mucosal flap, as well as to examine protective measures for the venous system of the nasal septal mucosal flap and its application in repairing the nasal skull base through the anatomical study of the nasal septum mucosal venous system in cadavers.Methods:Gross anatomy dissections were performed on 13 sides perfused fresh frozen cadaveric head specimens. The nasal septum mucosal flap was separated along the perichondrium and subperiosteum, then passed across the vomer, anterior wall of sphenoid sinus, clivus, and towards the anterior edge of vertical plate of palatine bone. Detailed documentation, including photographs, was made to record the morphology, distribution and drainage location of veins of the nasal septum mucosal flap and its pedicle, along with number of sphenopalatine veins. Furthermore, venous injuries resulting from obtaining a pedicled nasal septal mucosa flap were observed. From March 2023 to March 2024, a retrospective analysis was conducted on patients with nasopharyngeal lesions who underwent surgical repair using a modified pedicled nasal septum mucosal flap for venous system protection in the ENT institute and Department of Otorhinolaryngology at the Eye & ENT Hospital of Fudan University. The postoperative endoscopy was employed to assess the viability of the mucosal flap.Results:The veins of the nasal septum mucosa were primarily located in the posterior region, including the vomerine region, anterior wall of the sphenoid sinus, clivus region, and posterolateral wall of the nasal cavity, in a reticular pattern. Perforating veins draining into these bony structures could be observed, although their quantity and morphology varied. Notably, no prominent sphenopalatine veins were identified in 10 specimens examined, while 3 specimens exhibited sphenopalatine veins: one with a small single branch and two with venous bundles. Preservation of the nasal septal vein was possible when dissection was limited to the anterior edge of the wing of vomer. A wider range of dissection increased the risk of veinous injury. In cases where only vascular pedicles at the sphenopalatine foramen were preserved, three cadaveric head specimens retained intact sphenopalatine veins, while drainage veins were completely destroyed in ten other specimens. Fifteen patients with unilateral lesions (8 with recurrent nasopharyngeal carcinoma and 7 with nasopharyngeal radionecrosis) were included in this study. The postoperative reconstructions were carried out using contralateral pedicled nasal septal mucosal flaps. The average follow-up time was 7 months (ranging from 3 to 12 months), and all the nasal septal mucosal flaps survived.Conclusions:The primary location of the drainage vein within the nasal septum mucosa is situated in its posterior region, where it penetrates into adjacent bone structures. Very few sphenopalatine veins pass through the sphenopalatine foramen. Extensive dissection of the pedicled nasal septal mucosal flap may potentially impair the venous system and adversely affect flap survival rates, necessitating further clinical exploration.

Objective To explore the mechanism of electroacupuncture pretreatment(EP)for relieving post-stroke spasticity in rats.Methods Eighteen rats were randomized equally into sham-operated group,middle cerebral artery occlusion(MCAO)group,and MCAO+EP group.In MCAO+EP group,the rats received electroacupuncture at the acupoints Qubin and Baihui for 3 consecutive days prior to MCAO.Neurological deficits and cognitive function of the rats were evaluated,and pathologies in the hippocampus were examined using HE,Nissl,and TUNEL staining.The expressions of IL-4,IL-6,TNF-α,and TMAO in the brain tissues were detected with ELISA,and the mRNA and protein expression levels of NF-κB p65,NLRP3,caspase-3,and caspase-9 were determined with qRT-PCR,Western blotting,and immunohistochemistry.Results The rats receiving MCAO had significantly increased neurological deficit scores and showed increased muscle tension,number of apoptotic neurons,and expressions of IL-6,TNF-α,NF-κB p65,NLRP3,caspase-3 and caspase-9 in the hippocampus and significantly reduced length of time for new object recognition.Microscopically,the cells in the hippocampus of the MCAO rats showed uneven and loosened arrangement and unclear cell boundaries.In contrast,the rats in I/R+EP group showed significantly lowered neurological deficit scores and dystonia rating scores,reduced cell apoptosis,lowered hippocampal expressions of IL-6,TNF-α,caspase-3,caspase-9,and NF-κB p65,increased time for new object recognition,tightly arranged and uniformly stained hippocampal cells with clear boundaries,with also an increased number of active neurons and enhanced expression of IL-4 in the hippocampus.Conclusion EP alleviates post-stroke spasticity in rats by inhibiting inflammatory responses and hippocampal neuronal apoptosis mediated by the NF-κB/NLRP3 signaling pathway.

Objective:To report the results of national surveillance on the distribution and antimicrobial resistance profile of clinical Gram-positive bacteria isolates from bloodstream infections in China in 2022.Methods:The clinical isolates of Gram-positive 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:A total of 3 163 strains of Gram-positive pathogens were collected from 51 member units，and the top five bacteria were Staphylococcus aureus（ n=1 147，36.3%），coagulase-negative Staphylococci（ n=928，29.3%）， Enterococcus faecalis（ n=369，11.7%）， Enterococcus faecium（ n=296，9.4%）and alpha-hemolyticus Streptococci（ n=192，6.1%）. The detection rates of methicillin-resistant Staphylococcus aureus（MRSA）and methicillin-resistant coagulase-negative Staphylococci（MRCNS）were 26.4%（303/1 147）and 66.7%（619/928），respectively. No glycopeptide and daptomycin-resistant Staphylococci were detected. The sensitivity rates of Staphylococcus aureus to cefpirome，rifampin，compound sulfamethoxazole，linezolid，minocycline and tigecycline were all >95.0%. Enterococcus faecium was more prevalent than Enterococcus faecalis. The resistance rates of Enterococcus faecium to vancomycin and teicoplanin were both 0.5%（2/369），and no vancomycin-resistant Enterococcus faecium was detected. The detection rate of MRSA in southern China was significantly lower than that in other regions（ χ2=14.578， P=0.002），while the detection rate of MRCNS in northern China was significantly higher than that in other regions（ χ2=15.195， P=0.002）. The detection rates of MRSA and MRCNS in provincial hospitals were higher than those in municipal hospitals（ χ2=13.519 and 12.136， P<0.001）. The detection rates of MRSA and MRCNS in economically more advanced regions（per capita GDP≥92 059 Yuan in 2022）were higher than those in economically less advanced regions（per capita GDP<92 059 Yuan）（ χ2=9.969 and 7.606， P=0.002和0.006）. Conclusions:Among the Gram-positive pathogens causing bloodstream infections in China， Staphylococci is the most common while the MRSA incidence decreases continuously with time；the detection rate of Enterococcus faecium exceeds that of Enterococcus faecalis. The overall prevalence of vancomycin-resistant Enterococci is still at a low level. The composition ratio of Gram-positive pathogens and resistant profiles varies slightly across regions of China，with the prevalence of MRSA and MRCNS being more pronounced in provincial hospitals and areas with a per capita GDP≥92 059 yuan.