Objective:To investigate the differential impact of ultra-high-resolution photon-counting detector CT (UHR PCD-CT) and energy-integrating detector CT (EID-CT) on image quality and calcified plaque-induced luminal stenosis in coronary CT angiography (CCTA).Methods:This retrospective analysis was conducted on patients who underwent both EID-CT and UHR PCD-CT CCTA at the Geriatric Hospital of Nanjing Medical University between January 2021 and November 2024. A total of 141 patients were included in the study, within 46 patients having scans within a 12-month interval. Image quality of all coronary artery segments was subjectively evaluated. Patients with paired scans (interval≤12 months) were included for calcified plaque analysis. Subjective visualization of calcified plaques evaluated. The blooming artifact was calculated as an objective evaluation index for assessing the calcified plaques. Additionally, the degree of coronary artery lumen stenosis resulting from calcified plaques was assessed, along with the measurement of plaque volume and the Agatston score. Changes in lumen stenosis between the two scans were also evaluated. The Wilcoxon signed-rank test was used to compare the subjective scores of coronary artery image quality and calcified plaques between the two groups, and paired-sample t-tests were used to compare the blooming artifact and lumen stenosis degree. Results:The PCD-CT image quality score was significantly higher than that of EID-CT [PCD-CT : 5 (4,5), EID-CT: 4 (4,5); Z=-21.38, P<0.001]. Compared to EID-CT, PCD-CT reduced the blooming artifact (PCD-CT: 38.88%±9.09%, EID-CT: 50.11%±11.52%; t=-12.97, P<0.001), significantly improving the subjective score for visualization of calcified plaques [PCD-CT: 5 (4,5), EID-CT: 3 (2,3); Z=-9.68, P<0.001], and the measured lumen stenosis was notably lower in PCD-CT(PCD-CT:34.88%±18.20%, EID-CT:45.31%±23.42%; t=-9.93, P<0.001). Among 129 analyzed calcified plaques, luminal stenosis was reduced on PCD-CT in 110 plaques (85.3%) and increased in 19 (14.7%), including 4 plaques that had unclear boundaries with the adjacent lumen in EID-CT CCTA images, making the stenosis difficult to assess. Conclusion:Compared to EID-CT, UHR PCD-CT for CCTA significantly improves coronary artery image quality, provides clearer visualization of calcified plaques and adjacent lumen details, and it can reduce the overestimation of coronary artery caleified plaque stenosis.

Objective:To report the nationwide surveillance results of pathogenic profiles and antimicrobial resistance patterns of Gram-positive bloodstream infections in China in 2023.Methods:The clinical isolates of Gram-posttive bacteria from blood cultures were collected in member hospitals of National Bloodstream Infection Bacterial Resistant Investigation Collaborative System（BRICS）during January to December 2023. Antimicrobial susceptibility testing was performed using the dilution method recommended by the Clinical and Laboratory Standards Institute（CLSI）. Statistical analyses were conducted using WHONET 5.6 and SPSS 25.0 software.Results:A total of 4 385 Gram-positive bacterial isolates were obtained from 60 participating center. The top five pathogens were Staphylococcus aureus（ n=1 544，35.2%），coagulase-negative Staphylococci（ n=1 441，32.9%）， Enterococcus faecium（ n=574，13.1%）， Enterococcus faecalis（ n=385，8.8%），and α-hemolytic Streptococci（ n=187，4.3%）. The prevalence of methicillin-resistant Staphylococcus aureus（MRSA）and methicillin-resistant coagulase-negative Staphylococci（MRCNS）was 26.2%（405/1 544）and 69.8%（1 006/1 441），respectively. Notably，all Staphylococci remained susceptible to glycopeptide or daptomycin. Staphylococcus aureus demonstrated excellent susceptibility（>97.0%）to cephalobiol，rifampicin，trimethoprim-sulfamethoxazole，linezolid，minocycline，tigecycline，and eravacycline. No Enterococcus exhibiting resistance to linezolid were detected. Glycopeptide resistance was uncommon but more frequent in Enterococcus faecium（resistance to vancomycin and teicoplanin：both 1.7%）compared to Enterococcus faecalis（both 0.3%）. The detection rates of MRSA and MRCNS exhibited significant regional variations across the country（ χ2=17.674 and 148.650，respectively，both P<0.001）. No vancomycin-resistant Enterococci were detected in central China. Institutional comparison demonstrated higher prevalence of MRSA（ χ2=14.111， P<0.001）and MRCNS（ χ2=4.828， P=0.028）in provincial hospitals than that in municipal hospitals. Socioeconomic analysis identified elevated detection rates of both MRSA（ χ2=18.986， P<0.001）and MRCNS（ χ2=4.477， P=0.034）in less developed regions（per capita GDP

Objective:To report the results of bacterial resistant investigation collaborative system（BRICS）on the distribution and antimicrobial resistance profile of clinical Gram-negative bacteria isolates from bloodstream infections in China in 2023，and provide reference for clinical tretment of bloodstream infections and prevention and control of bacterial resistance.Methods:The clinical isolates of Gram-negative bacteria from blood cultures in member hospitals of BRICS were collected during January 2023 to December 2023. 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 were used to analyze the data.Results:During the study period，11 492 strains of Gram-negative bacteria were collected from 60 hospitals，of which 10 098（87.9%）were Enterobacterales and 1 394（12.1%）were non-fermentative bacteria. The top 5 bacterial species were Escherichia coli（50.0%）， Klebsiella pneumoniae（26.1%）， Pseudomonas aeruginosa（5.1%）， Acinetobacter baumannii complex（5.0%）and Enterobacter cloacae complex（4.1%）. The ESBL-producing rates in Escherichia coli， Klebsiella pneumoniae and Proteus mirablilis were 46.8%（2 685/5 741），18.3%（549/2 999）and 44.0%（77/175），respectively. The prevalence of carbapenem-resistant Escherichia coli（CREC）and carbapenem-resistant Klebsiella pneumoniae（CRKP）were 1.3%（76/5 741）and 15.0%（450/2 999）；32.9%（25/76）and 78.0%（351/450）of CREC and CRKP were sensitive to ceftazidime/avibactam combination，respectively. 94.7%（72/76）and 90.2%（406/450）of CREC and CRKP were sensitive to aztreonam/avibactam combination. Furthermore，57.9%（44/76）and 79.1%（356/450）were sensitive to imipenem/relebactam combination. The prevalence of carbapenem-resistant Acinetobacter baumannii（CRAB）complex was 64.6%（370/573），while more than 80.0% of CRAB complex was sensitive to tigecycline，eravacycline and polymyxin B. The prevalence of carbapenem-resistant Pseudomonas aeruginosa（CRPA）was 17.0%（99/581）. There were differences in the composition ratio of Gram-negative bacteria in bloodstream infections and the prevalence of important Gram-negative bacteria resistance among different regions in China，with statistically significant differences in the prevalence of CREC，CRKP，CRPA and CRAB complex（ χ2=10.6，28.6，10.8 and 19.3， P<0.05）. The prevalence of ESBL-producing Escherichia coli， CREC，CRAB complex and CRKP were higher in provincial hospitals than those in municipal hospitals（ χ2=12.5，9.8，12.7 and 57.8，all P<0.01）. Conclusions:Gram-negative bacteria are the main pathogens causing bloodstream infections in China，and Escherichia coli is ranked in the top，while the trend of Klebsiella pneumoniae increases continuously with time. CRKP infection shows a slow upward trend，CREC infecton maintains a low prevalence level，and CRAB complex infection continues to exhibit a high prevalence rate. The composition and resistance patterns of pathogens causing bloodstream infections vary to some extent across different regions and levels of hospitals in China.

BACKGROUND:In the repair of large bone defects,a variety of factors such as seed cell passaging can cause senescence of osteoblasts,leading to a reduction in osteogenic differentiation activity after implantation of tissue-engineered bone.In recent years,a novel mechanism involving primary cilia in cell senescence has been widely studied,but the primary cilia-related mechanism of"passage senescence-reduced osteogenic activity"is not fully understood.OBJECTIVE:To explore the possible mechanisms by which primary cilia regulate the senescence of MC3T3-E1 cells.METHODS:The osteoblast precursor cell lines MC3T3-E1 were passaged to 10th generation cells(early passage)and 40th generation cells(late passage).siRNA was used to silence IFT88 to inhibit primary cilia formation.The cells were than grouped into passage 10 group,passage 40 group,passage 10+siRNA IFT88 group,and passage 40+siRNA IFT88 group.RT-PCR and western blot assays were used to detect the expression of the aging marker P16(CDKN2A),the osteogenic activity markers bone morphogenetic protein 2 and alkaline phosphatase,and the Hedgehog pathway IHH expression.Alizarin red staining and primary cilia immunofluorescence staining were performed.Spearman correlation analysis was conducted to analyze primary cilia positive rate and IHH and bone morphogenetic protein 2 expression.RESULTS AND CONCLUSION:(1)The expression of CDKN2A(P16)in the passage 10 group was significantly higher than in the passage 40 group,but the difference disappeared after siRNA IFT88 intervention.(2)Meanwhile,the positive rate of primary cilia cells in the passage 10 group were higher than in the passage 40 group,while siRNA IFT88-significantly inhibited the expression of primary cilia in both passage 10 and passage 40 cells.(3)The transcriptional activity and protein expression of bone morphogenetic protein 2 and alkaline phosphatase in the passage 10 group were higher than those in the passage 40 group.After inhibiting the expression of primary cilia with siRNA,the above differences were reduced or disappeared.(4)The positive rate of primary cilia cells was correlated with IHH and bone morphogenetic protein 2 protein expression.To conclude,primary cilia mediate the replicative senescence of osteogenic MC3T3-E1 cells and regulate osteogenic differentiation ability.

BACKGROUND:In the repair of large bone defects,a variety of factors such as seed cell passaging can cause senescence of osteoblasts,leading to a reduction in osteogenic differentiation activity after implantation of tissue-engineered bone.In recent years,a novel mechanism involving primary cilia in cell senescence has been widely studied,but the primary cilia-related mechanism of"passage senescence-reduced osteogenic activity"is not fully understood.OBJECTIVE:To explore the possible mechanisms by which primary cilia regulate the senescence of MC3T3-E1 cells.METHODS:The osteoblast precursor cell lines MC3T3-E1 were passaged to 10th generation cells(early passage)and 40th generation cells(late passage).siRNA was used to silence IFT88 to inhibit primary cilia formation.The cells were than grouped into passage 10 group,passage 40 group,passage 10+siRNA IFT88 group,and passage 40+siRNA IFT88 group.RT-PCR and western blot assays were used to detect the expression of the aging marker P16(CDKN2A),the osteogenic activity markers bone morphogenetic protein 2 and alkaline phosphatase,and the Hedgehog pathway IHH expression.Alizarin red staining and primary cilia immunofluorescence staining were performed.Spearman correlation analysis was conducted to analyze primary cilia positive rate and IHH and bone morphogenetic protein 2 expression.RESULTS AND CONCLUSION:(1)The expression of CDKN2A(P16)in the passage 10 group was significantly higher than in the passage 40 group,but the difference disappeared after siRNA IFT88 intervention.(2)Meanwhile,the positive rate of primary cilia cells in the passage 10 group were higher than in the passage 40 group,while siRNA IFT88-significantly inhibited the expression of primary cilia in both passage 10 and passage 40 cells.(3)The transcriptional activity and protein expression of bone morphogenetic protein 2 and alkaline phosphatase in the passage 10 group were higher than those in the passage 40 group.After inhibiting the expression of primary cilia with siRNA,the above differences were reduced or disappeared.(4)The positive rate of primary cilia cells was correlated with IHH and bone morphogenetic protein 2 protein expression.To conclude,primary cilia mediate the replicative senescence of osteogenic MC3T3-E1 cells and regulate osteogenic differentiation ability.

Objective:To investigate the differential impact of ultra-high-resolution photon-counting detector CT (UHR PCD-CT) and energy-integrating detector CT (EID-CT) on image quality and calcified plaque-induced luminal stenosis in coronary CT angiography (CCTA).Methods:This retrospective analysis was conducted on patients who underwent both EID-CT and UHR PCD-CT CCTA at the Geriatric Hospital of Nanjing Medical University between January 2021 and November 2024. A total of 141 patients were included in the study, within 46 patients having scans within a 12-month interval. Image quality of all coronary artery segments was subjectively evaluated. Patients with paired scans (interval≤12 months) were included for calcified plaque analysis. Subjective visualization of calcified plaques evaluated. The blooming artifact was calculated as an objective evaluation index for assessing the calcified plaques. Additionally, the degree of coronary artery lumen stenosis resulting from calcified plaques was assessed, along with the measurement of plaque volume and the Agatston score. Changes in lumen stenosis between the two scans were also evaluated. The Wilcoxon signed-rank test was used to compare the subjective scores of coronary artery image quality and calcified plaques between the two groups, and paired-sample t-tests were used to compare the blooming artifact and lumen stenosis degree. Results:The PCD-CT image quality score was significantly higher than that of EID-CT [PCD-CT : 5 (4,5), EID-CT: 4 (4,5); Z=-21.38, P<0.001]. Compared to EID-CT, PCD-CT reduced the blooming artifact (PCD-CT: 38.88%±9.09%, EID-CT: 50.11%±11.52%; t=-12.97, P<0.001), significantly improving the subjective score for visualization of calcified plaques [PCD-CT: 5 (4,5), EID-CT: 3 (2,3); Z=-9.68, P<0.001], and the measured lumen stenosis was notably lower in PCD-CT(PCD-CT:34.88%±18.20%, EID-CT:45.31%±23.42%; t=-9.93, P<0.001). Among 129 analyzed calcified plaques, luminal stenosis was reduced on PCD-CT in 110 plaques (85.3%) and increased in 19 (14.7%), including 4 plaques that had unclear boundaries with the adjacent lumen in EID-CT CCTA images, making the stenosis difficult to assess. Conclusion:Compared to EID-CT, UHR PCD-CT for CCTA significantly improves coronary artery image quality, provides clearer visualization of calcified plaques and adjacent lumen details, and it can reduce the overestimation of coronary artery caleified plaque stenosis.

Objective:To report the nationwide surveillance results of pathogenic profiles and antimicrobial resistance patterns of Gram-positive bloodstream infections in China in 2023.Methods:The clinical isolates of Gram-posttive bacteria from blood cultures were collected in member hospitals of National Bloodstream Infection Bacterial Resistant Investigation Collaborative System（BRICS）during January to December 2023. Antimicrobial susceptibility testing was performed using the dilution method recommended by the Clinical and Laboratory Standards Institute（CLSI）. Statistical analyses were conducted using WHONET 5.6 and SPSS 25.0 software.Results:A total of 4 385 Gram-positive bacterial isolates were obtained from 60 participating center. The top five pathogens were Staphylococcus aureus（ n=1 544，35.2%），coagulase-negative Staphylococci（ n=1 441，32.9%）， Enterococcus faecium（ n=574，13.1%）， Enterococcus faecalis（ n=385，8.8%），and α-hemolytic Streptococci（ n=187，4.3%）. The prevalence of methicillin-resistant Staphylococcus aureus（MRSA）and methicillin-resistant coagulase-negative Staphylococci（MRCNS）was 26.2%（405/1 544）and 69.8%（1 006/1 441），respectively. Notably，all Staphylococci remained susceptible to glycopeptide or daptomycin. Staphylococcus aureus demonstrated excellent susceptibility（>97.0%）to cephalobiol，rifampicin，trimethoprim-sulfamethoxazole，linezolid，minocycline，tigecycline，and eravacycline. No Enterococcus exhibiting resistance to linezolid were detected. Glycopeptide resistance was uncommon but more frequent in Enterococcus faecium（resistance to vancomycin and teicoplanin：both 1.7%）compared to Enterococcus faecalis（both 0.3%）. The detection rates of MRSA and MRCNS exhibited significant regional variations across the country（ χ2=17.674 and 148.650，respectively，both P<0.001）. No vancomycin-resistant Enterococci were detected in central China. Institutional comparison demonstrated higher prevalence of MRSA（ χ2=14.111， P<0.001）and MRCNS（ χ2=4.828， P=0.028）in provincial hospitals than that in municipal hospitals. Socioeconomic analysis identified elevated detection rates of both MRSA（ χ2=18.986， P<0.001）and MRCNS（ χ2=4.477， P=0.034）in less developed regions（per capita GDP

Objective:To report the results of bacterial resistant investigation collaborative system（BRICS）on the distribution and antimicrobial resistance profile of clinical Gram-negative bacteria isolates from bloodstream infections in China in 2023，and provide reference for clinical tretment of bloodstream infections and prevention and control of bacterial resistance.Methods:The clinical isolates of Gram-negative bacteria from blood cultures in member hospitals of BRICS were collected during January 2023 to December 2023. 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 were used to analyze the data.Results:During the study period，11 492 strains of Gram-negative bacteria were collected from 60 hospitals，of which 10 098（87.9%）were Enterobacterales and 1 394（12.1%）were non-fermentative bacteria. The top 5 bacterial species were Escherichia coli（50.0%）， Klebsiella pneumoniae（26.1%）， Pseudomonas aeruginosa（5.1%）， Acinetobacter baumannii complex（5.0%）and Enterobacter cloacae complex（4.1%）. The ESBL-producing rates in Escherichia coli， Klebsiella pneumoniae and Proteus mirablilis were 46.8%（2 685/5 741），18.3%（549/2 999）and 44.0%（77/175），respectively. The prevalence of carbapenem-resistant Escherichia coli（CREC）and carbapenem-resistant Klebsiella pneumoniae（CRKP）were 1.3%（76/5 741）and 15.0%（450/2 999）；32.9%（25/76）and 78.0%（351/450）of CREC and CRKP were sensitive to ceftazidime/avibactam combination，respectively. 94.7%（72/76）and 90.2%（406/450）of CREC and CRKP were sensitive to aztreonam/avibactam combination. Furthermore，57.9%（44/76）and 79.1%（356/450）were sensitive to imipenem/relebactam combination. The prevalence of carbapenem-resistant Acinetobacter baumannii（CRAB）complex was 64.6%（370/573），while more than 80.0% of CRAB complex was sensitive to tigecycline，eravacycline and polymyxin B. The prevalence of carbapenem-resistant Pseudomonas aeruginosa（CRPA）was 17.0%（99/581）. There were differences in the composition ratio of Gram-negative bacteria in bloodstream infections and the prevalence of important Gram-negative bacteria resistance among different regions in China，with statistically significant differences in the prevalence of CREC，CRKP，CRPA and CRAB complex（ χ2=10.6，28.6，10.8 and 19.3， P<0.05）. The prevalence of ESBL-producing Escherichia coli， CREC，CRAB complex and CRKP were higher in provincial hospitals than those in municipal hospitals（ χ2=12.5，9.8，12.7 and 57.8，all P<0.01）. Conclusions:Gram-negative bacteria are the main pathogens causing bloodstream infections in China，and Escherichia coli is ranked in the top，while the trend of Klebsiella pneumoniae increases continuously with time. CRKP infection shows a slow upward trend，CREC infecton maintains a low prevalence level，and CRAB complex infection continues to exhibit a high prevalence rate. The composition and resistance patterns of pathogens causing bloodstream infections vary to some extent across different regions and levels of hospitals in China.

Objective:To investigate the biological effects of acute high-dose radon exposure on mice.Methods:BALB/c male mice aged 6 to 8 weeks were exposed once in an HD-3 ecological radon chamber with an average radon concentration of 7 × 10 5 Bq/m 3 for 10 h. Mice were weighed, their lung tissues and blood samples were collected at 1, 2 and 3 months after exposure. Control groups were set up at the three time points with four mice in each group. For these mice, the lung tissue pathology was observed using hematoxylin-eosin (HE) staining method, routine blood tests were conducted using a hematology analyzer and the levels of superoxide dismutase (SOD) and malondialdehyde (MDA) in the serum and lung tissues were measured using corresponding assay kits. Results:The HE staining result revealed that compared to the control groups, the experimental groups exhibited thickening of alveolar walls and increased infiltration of granulocyte, whose degrees, however, reduced over time and displayed no significant difference at 3 months after exposure. There was no significant difference in body weight or blood routine between the experimental and control groups. The detection result revealed decreased SOD levels in the lung tissues at 2 months after exposure, which were (11.34 ± 1.03) U/mgprot and (9.75 ± 0.71) U/mgprot, respectively for the control and experimental groups ( t = 2.54, P < 0.05). The MDA levels in lung tissue increased at 1 month after exposure, which were(2.30 ± 0.24) and (2.77 ± 0.29) nmol/mgprot, respectively for the control and experimental groups ( t = 2.49, P < 0.05). At 3 months after exposure, the SOD and MDA levels differed insignificantly between the control and experimental groups ( P > 0.05). Conclusions:After acute high-dose radon exposure, the mice suffered damage to the lung tissue, with changes in their oxidative stress indicators being detected. However, these effects gradually diminished at 3 months after exposure. Additionally, acute high-dose radon exposure did not give rise to significant changes in the body weight or routine blood result of the mice.

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.