Objective To analyze the clinical distribution,drug resistance characteristics,molecular prevalence,and impact of immunocompromised status on the infection rate of carbapenem-resistant Enterobacteriaceae(CRE)isolated from pediatric respiratory tract samples(sputum,bronchoalveolar lavage fluid).Methods A retrospective analysis was conducted on clinical data of hospitalized children from 2019 to 2023.A total of 1 235 non-repetitive strains of Enterobacteriaceae bacteria were obtained from pediactric respiratory tract samples.Drug susceptibility testing,multilocus sequencing typing(MLST),and resistance-related gene sequencing were performed on 100 isolated CRE strains,to study the clinical distribution,drug resistance characteristics,and molecular prevalence of CRE,and to further analyze the impact of immunocompromised status on the respiratory CRE infection rate in children.Results From 2019 to 2023,the detection rate of CRE in 1 235 strains of Enterobacteriaceae bacteria was 8.10%(100/1 235).Among them,51.0%(51/100)of CRE were isolated from the intensive care unit(ICU),of which 33.0%(33/100)were isolated from the Surgical ICU,18.0%(18/100)of CRE was isolated from the Medical ICU;32.0%(32/100)of CRE were isolated from Department of Neonatology,with the majority(74.0%)isolated from infants under 6 months of age.Of all pediatric patients,85.0%recovered and were discharged after treatment.Immunocompromised status was identified as an independent risk factor for CRE infection.Among 100 strains of CRE,Carbapenem-resistant Klebsiella pneumoniae(CRKP)was the most commonly detected strain,accounting for 88.0%(88/100),followed by Escherichia coli at 6.0%(6/100)and Enterobacter cloacae at 4.0%(4/100).CRE strains were highly resistant to carbapenems and cephalosporins,with prevalent resistance to amikacin,ciprofloxacin,and levofloxacin.However,their resistance rates were relatively low to tigecycline,colistin,minocycline,ceftazidime/avibactam,meropenem/vaborbactam,and imipenem/relebactam.The screening results of carbapenem resistance genes showed that blaKPC-2 was the most prevalent gene(74.0%),followed by blaNDM-1(14.0%)and blaNDM-5(11.0%).Molecular typing showed that ST11 type CRE was the dominant type,comprising 72.0%(72/100)and was the primary epidemic clone.Conclusions CRKP is the most prevalent CRE strain isolated from pediatric respiratory tract samples,primarily identified in the ICU,Department of Neonatology,and among infants under 6 months of age.Immunocompromised status is an independent risk factor for respiratory CRE infection in children.CRE generally has high resistance to antibacterial drugs,with blaKPC-2 being the dominant resistance genotype,and ST11 as the predominant multilocus sequence type.Clinical management should account for these characteristics to implement timely interventions and rational therapeutic strategies.

Objective To investigate the expression profiles of microRNAs(miRNAs)in seminal plasma of the patients with hypervis-cous semen and explore their possible roles in the formation of seminal hyperviscosity.Methods Ten semen samples,including 5 with hyperviscosity(hyperviscosity group)and the other 5 without hyperviscosity(control group),were collected,and the seminal plasmas were obtained by centrifugation after completing semen analysis.The miRNAs in seminal plasma were extracted and performed sequen-cing using high-throughput sequencing technology based on the Illumina platform.The differences in miRNA expression between the two groups were compared.The differentially expressed miRNAs were validated by real-time fluorescence quantitative-PCR(qRT-PCR).The differentially expressed miRNAs were screened to predict their target genes.The Gene Ontology(GO)and KEGG Pathway were used for the enrichment analysis of functional significance.Results A total of 82 significantly differentially expressed miRNAs were found between the hyperviscosity group and the control group,of which 76 were up-regulated and 6 were down-regulated.The results of qRT-PCR validation showed that the expression trends of the differentially expressed miRNAs(miR-449a,miR-517a-3p,and miR-1257)were largely consistent with the high-throughput sequencing results.The GO functional classification annotation showed that their target genes were mainly enriched in ubiquitin-like protein ligase binding,kinase activity,and ion transmembrane transport activi-ty in molecular functions.They mainly participated in the regulation of neuronal apoptosis and ion transmembrane transport in biological processes,and the formation of cell membranes,Golgi membranes and phagocytic vesicles in cellular components.KEGG pathway en-richment analysis showed that the target genes were mainly enriched in signaling pathways,such as ErbB,neurotrophin,interaction with signaling molecules,signal transduction,and cancer-related signal pathways.Conclusion Various differentially expressed miRNAs existed in hyperviscous semen,which may provide a basis for finding a molecular marker or a group of markers in the diagno-sis and evaluation of the treatment for hyperviscous semen.

Objective To investigate the expression profiles of microRNAs(miRNAs)in seminal plasma of the patients with hypervis-cous semen and explore their possible roles in the formation of seminal hyperviscosity.Methods Ten semen samples,including 5 with hyperviscosity(hyperviscosity group)and the other 5 without hyperviscosity(control group),were collected,and the seminal plasmas were obtained by centrifugation after completing semen analysis.The miRNAs in seminal plasma were extracted and performed sequen-cing using high-throughput sequencing technology based on the Illumina platform.The differences in miRNA expression between the two groups were compared.The differentially expressed miRNAs were validated by real-time fluorescence quantitative-PCR(qRT-PCR).The differentially expressed miRNAs were screened to predict their target genes.The Gene Ontology(GO)and KEGG Pathway were used for the enrichment analysis of functional significance.Results A total of 82 significantly differentially expressed miRNAs were found between the hyperviscosity group and the control group,of which 76 were up-regulated and 6 were down-regulated.The results of qRT-PCR validation showed that the expression trends of the differentially expressed miRNAs(miR-449a,miR-517a-3p,and miR-1257)were largely consistent with the high-throughput sequencing results.The GO functional classification annotation showed that their target genes were mainly enriched in ubiquitin-like protein ligase binding,kinase activity,and ion transmembrane transport activi-ty in molecular functions.They mainly participated in the regulation of neuronal apoptosis and ion transmembrane transport in biological processes,and the formation of cell membranes,Golgi membranes and phagocytic vesicles in cellular components.KEGG pathway en-richment analysis showed that the target genes were mainly enriched in signaling pathways,such as ErbB,neurotrophin,interaction with signaling molecules,signal transduction,and cancer-related signal pathways.Conclusion Various differentially expressed miRNAs existed in hyperviscous semen,which may provide a basis for finding a molecular marker or a group of markers in the diagno-sis and evaluation of the treatment for hyperviscous semen.

Objective To analyze the clinical distribution,drug resistance characteristics,molecular prevalence,and impact of immunocompromised status on the infection rate of carbapenem-resistant Enterobacteriaceae(CRE)isolated from pediatric respiratory tract samples(sputum,bronchoalveolar lavage fluid).Methods A retrospective analysis was conducted on clinical data of hospitalized children from 2019 to 2023.A total of 1 235 non-repetitive strains of Enterobacteriaceae bacteria were obtained from pediactric respiratory tract samples.Drug susceptibility testing,multilocus sequencing typing(MLST),and resistance-related gene sequencing were performed on 100 isolated CRE strains,to study the clinical distribution,drug resistance characteristics,and molecular prevalence of CRE,and to further analyze the impact of immunocompromised status on the respiratory CRE infection rate in children.Results From 2019 to 2023,the detection rate of CRE in 1 235 strains of Enterobacteriaceae bacteria was 8.10%(100/1 235).Among them,51.0%(51/100)of CRE were isolated from the intensive care unit(ICU),of which 33.0%(33/100)were isolated from the Surgical ICU,18.0%(18/100)of CRE was isolated from the Medical ICU;32.0%(32/100)of CRE were isolated from Department of Neonatology,with the majority(74.0%)isolated from infants under 6 months of age.Of all pediatric patients,85.0%recovered and were discharged after treatment.Immunocompromised status was identified as an independent risk factor for CRE infection.Among 100 strains of CRE,Carbapenem-resistant Klebsiella pneumoniae(CRKP)was the most commonly detected strain,accounting for 88.0%(88/100),followed by Escherichia coli at 6.0%(6/100)and Enterobacter cloacae at 4.0%(4/100).CRE strains were highly resistant to carbapenems and cephalosporins,with prevalent resistance to amikacin,ciprofloxacin,and levofloxacin.However,their resistance rates were relatively low to tigecycline,colistin,minocycline,ceftazidime/avibactam,meropenem/vaborbactam,and imipenem/relebactam.The screening results of carbapenem resistance genes showed that blaKPC-2 was the most prevalent gene(74.0%),followed by blaNDM-1(14.0%)and blaNDM-5(11.0%).Molecular typing showed that ST11 type CRE was the dominant type,comprising 72.0%(72/100)and was the primary epidemic clone.Conclusions CRKP is the most prevalent CRE strain isolated from pediatric respiratory tract samples,primarily identified in the ICU,Department of Neonatology,and among infants under 6 months of age.Immunocompromised status is an independent risk factor for respiratory CRE infection in children.CRE generally has high resistance to antibacterial drugs,with blaKPC-2 being the dominant resistance genotype,and ST11 as the predominant multilocus sequence type.Clinical management should account for these characteristics to implement timely interventions and rational therapeutic strategies.

Objective:To evaluate the safety and efficacy of donor-purified CD34 + stem cell boosts in patients with poor hematopoietic reconstruction (PHR) after haploid hematopoietic stem cell transplantation (haplo-HSCT) for aplastic anemia (AA) . Method:A retrospective analysis was conducted on 11 patients with AA and PHR who underwent haplo-HSCT and received donor-purified CD34 + stem cell boosts at Peking University People’s Hospital. Recovery of blood cell counts, incidence of graft-versus-host disease (GVHD), and overall survival (OS) were assessed. Results:Of the 11 patients with PHR, two were diagnosed with prolonged isolated thrombocytopenia (PT), one was primary poor graft function (PGF), and eight were diagnosed with secondary PGF. The median time to PHR diagnosis was 110 days (range: 60-330 days), and the median interval from transplantation to purified CD34 + hematopoietic stem cell infusion was 194 days (range: 125-456 days). The two patients with PT achieved complete platelet recovery at 22 and 13 days after CD34 + stem cell infusion, respectively. Among the remaining nine patients with PGF, six achieved complete hematopoietic recovery, with a median absolute neutrophil count recovery time of 19 days (8-158 days), HGB recovery time of 32.5 days (range: 13-158 days), and platelet recovery time of 31.5 days (range: 7-171 days). The incidence of chronic GVHD after infusion was 18.2%, with no cases of acute GVHD observed. The OS rate was 90.9% (10/11) in the 11 patients, with a median follow-up of 614 days (range: 153-1 765 days) . Conclusion:Donor-purified CD34 + stem cell boost may be an effective therapeutic strategy for PHR in patients with AA after haplo-HSCT.

Objective:To evaluate the safety and efficacy of donor-purified CD34 + stem cell boosts in patients with poor hematopoietic reconstruction (PHR) after haploid hematopoietic stem cell transplantation (haplo-HSCT) for aplastic anemia (AA) . Method:A retrospective analysis was conducted on 11 patients with AA and PHR who underwent haplo-HSCT and received donor-purified CD34 + stem cell boosts at Peking University People’s Hospital. Recovery of blood cell counts, incidence of graft-versus-host disease (GVHD), and overall survival (OS) were assessed. Results:Of the 11 patients with PHR, two were diagnosed with prolonged isolated thrombocytopenia (PT), one was primary poor graft function (PGF), and eight were diagnosed with secondary PGF. The median time to PHR diagnosis was 110 days (range: 60-330 days), and the median interval from transplantation to purified CD34 + hematopoietic stem cell infusion was 194 days (range: 125-456 days). The two patients with PT achieved complete platelet recovery at 22 and 13 days after CD34 + stem cell infusion, respectively. Among the remaining nine patients with PGF, six achieved complete hematopoietic recovery, with a median absolute neutrophil count recovery time of 19 days (8-158 days), HGB recovery time of 32.5 days (range: 13-158 days), and platelet recovery time of 31.5 days (range: 7-171 days). The incidence of chronic GVHD after infusion was 18.2%, with no cases of acute GVHD observed. The OS rate was 90.9% (10/11) in the 11 patients, with a median follow-up of 614 days (range: 153-1 765 days) . Conclusion:Donor-purified CD34 + stem cell boost may be an effective therapeutic strategy for PHR in patients with AA after haplo-HSCT.

Objective:To delineate the clinical characteristics and outcomes associated with severe cardiac toxicity during the preconditioning phase of allogeneic hematopoietic stem cell transplantation (allo-HSCT) in patients with aplastic anemia (AA).Methods:This retrospective case series study included 31 patients with severe AA who underwent allo-HSCT and were diagnosed with severe cardiac toxicity at the Hematology Department of Peking University People′s Hospital from August 2012 to June 2022. The clinical manifestations of severe cardiac toxicity observed during the preconditioning process were assessed. Patient survival was assessed using the Kaplan-Meier method.Results:In this cohort of 31 patients, the median follow-up period was 9 days (range: 4-365 days). Severe cardiac toxicity manifested within 6 days after the initial cyclophosphamide (Cy) administration. Twenty patients died within 30 days of initiating Cy preconditioning, of which 16 patients died due to severe cardiac toxicity within 25 days. Patients whose cardiac function improved within 30 days post-preconditioning showed a median survival duration of 222 days ( n=11). Troponin I (TNI) levels in patients who died within 30 days of initiating Cy preconditioning began increasing on day 5 post-Cy, peaking sharply by day 9 after a notable rise on day 8. B-type natriuretic peptide (BNP) levels in patients who died within 30 days of initiating Cy preconditioning started to rise from day 1, stabilized between days 2 and 5, and then doubled daily from days 6 to 8, remaining elevated thereafter. Notably, the initial increases in BNP and TNI correlated with electrocardiogram (ECG) signs of low voltage and T-wave inversion in 83.87% of cases ( n=26). Most patients ( n=28, 90.32%) were administered corticosteroid therapy. In those with restored cardiac function, the ejection fraction returned to >50% within 30 days of initiating Cy preconditioning. Conclusions:Patients with severe cardiac toxicity during the preconditioning phase of allo-HSCT typically exhibit early, sustained, and marked elevations in myocardial damage markers, including BNP and TNI, accompanied by ECG abnormalities following Cy administration, with BNP often increasing first. These indicators are associated with rapid disease progression and high mortality. Prompt initiation of treatment upon clinical diagnosis is critical for improving survival outcomes.

Background The benchmark dose (BMD) method calculates the dose associated with a specific change in response based on a specific dose-response relationship. Compared with the traditional no observed adverse effect level (NOAEL) method, the BMD method has many advantages, and the 95% lower confidence limit of benchmark dose lower limit (BMDL) is recommended to replace NOAEL in deriving biological exposure limits. No authority has yet published any health-based guideline for rare earth elements. Objective To evaluate genotoxicity threshold induced by acute exposure to neodymium nitrate in mice using BMD modeling through micronucleus test and comet assay. Methods SPF grade mice (n=90) were randomly divided into nine groups, including seven neodymium nitrate exposure groups, one control group (distilled water), and one positive control group (200 mg·kg⁻¹ ethyl methanesulfonate), 10 mice in each group, half male and half female. The seven dose groups were fed by gavage with different concentrations of neodymium nitrate solution (male: 14, 27, 39, 55, 77, 109, and 219 mg·kg⁻¹; female: 24, 49, 69, 97, 138, 195, and 389 mg·kg⁻¹) twice at an interval of 21 h. Three hours after the last exposure, the animals were neutralized by cervical dislocation. The bone marrow of mice femur was taken to calculate the micronucleus rate of bone marrow cells, and the liver and stomach were taken for comet test. Results The best fitting models for the increase of polychromatophil micronucleus rate in bone marrow of female and male mice induced by neodymium nitrate were the exponential 4 model and the hill model, respectively. The BMD and the BMDL of female mice were calculated to be 31.37 mg·kg⁻¹ and 21.90 mg·kg⁻¹, and those of male mice were calculated to be 58.62 mg·kg⁻¹ and 54.31 mg·kg⁻¹, respectively. The best fitting models for DNA damage induced by neodymium nitrate in female and male mouse hepatocytes were the exponential 5 model and the exponential 4 model, respectively, and the calculated BMD and BMDL were 27.15 mg·kg⁻¹ and 11.99 mg·kg⁻¹ for female mice, and 16.28 mg·kg⁻¹ and 10.47 mg·kg⁻¹ for male mice, respectively. The hill model was the best fitting model for DNA damage of gastric adenocytes in both female and male mice, and the calculated BMD and BMDL were 36.73 mg·kg⁻¹ and 19.92 mg·kg⁻¹ for female mice, and 24.74 mg·kg⁻¹ and 14.08 mg·kg⁻¹ for male mice, respectively. Conclusion Taken the micronucleus rate of bone marrow cells, DNA damage of liver cells and gastric gland cells as the end points of genotoxicity, the BMDL of neodymium nitrate is 10.47 mg·kg⁻¹, which can be used as the threshold of genotoxic effects induced by acute exposure to neodymium nitrate in mice.

Background The respiratory toxicity of inhaled polyhexamethylene guanidine (PHMG) has been extensively studied since the humidifier disinfectant incident. However, the impacts of inhalation of PHMG on the immune system are not comprehensively studied yet. Objective To explore the effects of inhalation of PHMG disinfectant aerosol on major immune organs and immune cells in mice. Methods Thirty male C57BL/6J mice (6-8 weeks old) were randomly divided into three groups: control, low-dose (0.1 mg·m⁻³ PHMG), and high-dose (1.0 mg·m⁻³ PHMG), with ten mice in each group. The mice were administered by oral-nasal inhalation of PHMG aerosol for 4 h per day, 5 d per week for 4 weeks consecutively. After designed treatment, venous blood was collected from the inner canthus of the eyes of mice and peripheral hematological indicators were measured with a blood analyzer. Then the mice were sacrificed by cervical dislocation and the lung, thymus, spleen, and femur were isolated. Lung, thymus, and spleen were weighed and organ coefficients were calculated, and single cell suspensions of thymus, spleen, and bone marrow were prepared to analyze lymphocytes phenotypes and proportions by flow cytometry. Results The body weight of mice in the high-dose group was lower than that of mice in the control group (P<0.01) from the 7th day of inhalation, and decreased by 15.74% compared with that of mice in the control group at the end of inhalation (P<0.01). The lung coefficients of both the low-dose and high-dose groups were higher than that of the control group (P<0.01), the thymus coefficient of mice in the high-dose group was lower than that of the control group (P<0.05), but the spleen coefficient did not change significantly (P>0.05). Leukocyte count [(1.49±0.22)×10⁹·L⁻¹], lymphocyte count [(0.96±0.36)×10⁹·L⁻¹] and its proportion [(63.13±14.96)%] in the peripheral blood of mice in the high-dose group were lower than those in the control group [(2.69±0.25)×10⁹·L⁻¹, (2.33±0.28)×10⁹·L⁻¹, and (86.23±3.40)%, respectively] (P<0.01), whereas red blood cell count [(12.32±0.46)×10¹²·L⁻¹], hemoglobin count [(175.25±4.65) g·L⁻¹], and hematocrit [(53.55±0.70)%] in the peripheral blood of mice in the high-dose group were higher than those in the control group [(11.11±0.37)×10¹²·L⁻¹, (160.67±4.04) g·L⁻¹, and (45.10±9.75)%, respectively] (P<0.05). Compared with the control group, the proportion of CD4+ CD8+ double-positive T cells decreased (P<0.05), the proportions of CD4+ T cells and CD8+ T cells increased (P<0.05), and the amounts of CD8+, CD4+ CD8+, CD4+, and CD4- CD8- cells decreased (P<0.05) in the thymus of mice of the high-dose group, the proportion of CD4+ T cells in the spleen of the high-dose group increased (P<0.05), the proportions and amounts of T cells, CD4+ T cells, and CD8+ T cells in the bone marrow of the high-dose group increased (P<0.05). Conclusion Inhalation of PHMG may cause thymic atrophy, disrupt T-lymphocyte development, and lead to an imbalance in the number of immune cells in the bone marrow, peripheral blood, and spleen, suggesting that inhalation of PHMG induces immune dysfunction.

AIM:To explore the fundus vascular characteristics of healthy individuals based on deep learning techniques, with a view to discovering the range of normal values of the fundus arteries and veins, as well as the relationship between physiological factors, such as gender, age, body mass index(BMI), blood pressure, and fundus vasculature characteristics.METHODS:Fundus images of healthy people were taken from a professional fundus camera, and the subject's blood pressure and laboratory test was collected. Additionally, the fundus arteries and veins were segmented by the improved U-Net model, and the color, morphology and Haralick texture features of the vessels were extracted from computer vision technology.RESULTS:A total of 4 487 cases fundus images were taken and 326 cases with healthy and clear fundus images were screened, including 200 males and 126 females. There were differences in the morphology, color, and textural characteristics of the left and right eyes, as well as of the fundus arterioles and veins, with a mean vessel width(width)of 1.146 in the arteries and 1.430 in the veins, and an arteriovenous ratio about 4:5. Fundus artery and vein characteristics in healthy individuals of different ages(21-30, 31-40, 41-50): compared with the healthy population aged 21-30 and 31-40 years, arterial and venous inverse difference moment(idm), f12 and venous angular second moment(asm)values increased, and arterial and venous contrast(con), entropy(ent), difference entropy(den), and venous sum entropy(sen)values decreased in 41-50 years. Compared with the 21-30 years age group, arterial f12 values increased and venous con values decreased in 31-40 years(all P<0.05). Fundus vascular characteristics of healthy individuals of different sexes: compared with male, fundus arterial and venous sum average(sav), sum variance(sva)values, arterial curved values, and venous b mean, bsd, variance(var), sen, ent values increased in female, while venous area value of female decreased(all P<0.05). There were no statistically significant differences in fundus arteriosus and venous features in healthy subjects with different levels of BMI(all P>0.05). Fundus characteristics of healthy people with different degrees of blood pressure: there were statistically significant differences in fundus arteriosus area, width, and venous con, idm, dva, and den values between the normal blood pressure and high blood pressure groups(all P<0.05).CONCLUSION: The characteristics of the left and right eyes as well as the fundus arteries and veins differ in healthy individuals and correlate with physiological factors such as gender, age and blood pressure, which have the value of a potential microcirculation marker.