Objective To establish orthotopic and ectopic pancreatic cancer models in C57BL/6N mice with normal immune function using in vivo imaging technology for visual characterization.Methods Orthotopic and ectopic pancreatic cancer models were established in Kunming mice by injecting a small volume of cell suspension containing firefly luciferase-expressing Panc02-luciferase pancreatic cancer cells into the head of the pancreas or the right axillary region.In vivo imaging technology was used to optimize the modeling method and timing in Kunming mice.Subsequently,the same method was applied to C57BL/6N mice using wild-type Panc02 pancreatic cancer cells to establish orthotopic and ectopic pancreatic cancer models with intact immune function.Key parameters,including body weight,inoculation positive rate,tumor growth time,tumor volume,and pathological characteristics across different organs,were compared be-tween the orthotopic and ectopic models in C57BL/6N mice to evaluate the applicability of these models.Results Both the small animal in vivo imaging experiments in Kunming mice and the tumor growth observation in C57BL/6N mice demonstrated that the construction periods for orthotopic and ectopic pancreatic cancer models were 20 days,with survival rates exceeding 90%.The inoculation positive rates in C57BL/6N mice were 92.3%for the orthotopic model and 78.6%for the ectopic model.On day 20 post-inoculation,the tumor volumes were(117.04±109.56)mm3 for the orthotopic model and(155.68±168.73)mm3 for the ectopic model,indicating high model success rates and consistent tumor growth.HE staining revealed pathological mitotic figures and poorly differentiated tumor tissues in both models of C57BL/6N mice,with no evidence of metastasis to other organs.Conclusions Orthotopic and ectopic pancreatic cancer models in immu-nocompetent mice were successfully developed in this study,mimicking early-stage pancreatic cancer characteristics.These models pro-vide a reliable platform for screening early diagnostic biomarkers and evaluating therapeutic interventions for pancreatic cancer.

Objective To observe the value of artificial intelligence iterative reconstruction(AIIR)for low-dose chest CT images of infants with congenital heart disease.Methods Totally 262 infants with congenital heart disease who would undergo chest CT scanning were prospectively enrolled and randomly divided into low-dose group(n=142)and conventional dose group(n=120).Chest CT scanning with tube voltage of 80 kVp and tube current of 10 mAs was performed in low-dose group,and hybrid iterative reconstruction(HIR,group A)and AIIR(group B)were used to reconstruct images,respectively.In conventional dose group,chest CT scanning with tube voltage of 80 kVp and tube current of 100 mAs was performed,and HIR was used to reconstruct images(group C).Then subjective and objective evaluation on image quality were performed,the results were compared among 3 groups,and the value of AIIR was analyzed.Results Significant differences of image quality and clarity of displaying structures were found among 3 groups(all P＜0.001).Among them,except for the clarity of interlobar fissure,no significant difference of subjective scores was found between low-dose AIIR images and conventional dose HIR images(all corrected P＞0.05),while subjective scores of low-dose HIR images were all lower than those of low-dose AIIR images and conventional dose HIR images(all corrected P＜0.05).Significant differences of standard deviation(SD),signal-to-noise ratio(SNR)and contrast-to-noise ratio(CNR)were found among 3 groups(all P＜0.001)and between each 2 groups(all corrected P＜0.05).The effective dose of low-dose group and conventional dose group was 0.09(0.08,0.10)and 0.85(0.75,1.03)mSv,respectively,and the former was lower than the latter(Z=-13.942,P＜0.001).Conclusion Using AIIR could obtain low-dose chest CT images of infants with quality comparable to conventional chest CT images.

Objective This study aimed to investigate the antimicrobial resistance profiles of bacterial strains isolated from pediatric intensive care units(PICU)in China for better antimicrobial therapy.Methods Clinical isolates were collected from 17 institutions,including tertiary care children's hospitals and pediatric department of tertiary general hospitals in China from January 1,2020 to December 31,2022.Antimicrobial susceptibility testing was carried out according to a unified protocol using Kirby-Bauer method or automated systems.Results were interpreted according to the breakpoints released by the Clinical and Laboratory Standards Institute(CLSI)in 2020.Results A total of 10 688 isolates were collected,including gram-positive organisms(39.2％)and gram-negative organisms(60.8％).The top three organisms were S.aureus(13.6％,1 453/10 688),A.baumannii(10.0％,1 067/10 688),and coagulase-negative Staphylococcus(9.9％,1 058/10 688).Multi-drug resistant organisms(MDROs)were very common in children.The prevalence of methicillin-resistant Staphylococcus aureus(MRSA),carbapenem-resistant Enterobacterales(CRE),carbapenem-resistant E.coli,carbapenem-resistant K.pneumoniae(CRKP),carbapenem-resistant A.baumannii(CRAB),and carbapenem-resistant P.aeruginosa(CRPA)was 41.1％,19.4％,8.8％,30.9％,67.4％,and 28.8％,respectively.Overall,more than 50％of Enterobacteriales isolates were resistant to cephalosporins,while nearly 25％of Enterobacteriales isolates were resistant to carbapenems.MDROs were highly resistant to commonly used antibiotics.More than 80％of CRE and CRAB strains were resistant to all beta-lactam antibiotics.CRE and CRAB showed low resistance rates to tigecycline and polymyxin.CRPA showed lower resistance rates to piperacillin,beta-lactamase inhibitor combinations than the resistance rates to third and fourth generation cephalosporins.All of the Staphylococcus and Enterococcus isolates were susceptible to vancomycin and tigecycline.None of PRSP strains isolated from meningitis and nonmeningitis samples were resistant to rifampicin,vancomycin,or linezolid.The prevalence of β-lactamase-negative ampicillin-resistant(BLNAR)strains was 43.3％in Haemophilus influenzae.Conclusions MDROs were prevalent in PICU.It is necessary to establish an effective multidisciplinary team(MDT)to control the antimicrobial resistance.

Objective To observe the value of artificial intelligence iterative reconstruction(AIIR)for low-dose chest CT images of infants with congenital heart disease.Methods Totally 262 infants with congenital heart disease who would undergo chest CT scanning were prospectively enrolled and randomly divided into low-dose group(n=142)and conventional dose group(n=120).Chest CT scanning with tube voltage of 80 kVp and tube current of 10 mAs was performed in low-dose group,and hybrid iterative reconstruction(HIR,group A)and AIIR(group B)were used to reconstruct images,respectively.In conventional dose group,chest CT scanning with tube voltage of 80 kVp and tube current of 100 mAs was performed,and HIR was used to reconstruct images(group C).Then subjective and objective evaluation on image quality were performed,the results were compared among 3 groups,and the value of AIIR was analyzed.Results Significant differences of image quality and clarity of displaying structures were found among 3 groups(all P＜0.001).Among them,except for the clarity of interlobar fissure,no significant difference of subjective scores was found between low-dose AIIR images and conventional dose HIR images(all corrected P＞0.05),while subjective scores of low-dose HIR images were all lower than those of low-dose AIIR images and conventional dose HIR images(all corrected P＜0.05).Significant differences of standard deviation(SD),signal-to-noise ratio(SNR)and contrast-to-noise ratio(CNR)were found among 3 groups(all P＜0.001)and between each 2 groups(all corrected P＜0.05).The effective dose of low-dose group and conventional dose group was 0.09(0.08,0.10)and 0.85(0.75,1.03)mSv,respectively,and the former was lower than the latter(Z=-13.942,P＜0.001).Conclusion Using AIIR could obtain low-dose chest CT images of infants with quality comparable to conventional chest CT images.

Objective To establish orthotopic and ectopic pancreatic cancer models in C57BL/6N mice with normal immune function using in vivo imaging technology for visual characterization.Methods Orthotopic and ectopic pancreatic cancer models were established in Kunming mice by injecting a small volume of cell suspension containing firefly luciferase-expressing Panc02-luciferase pancreatic cancer cells into the head of the pancreas or the right axillary region.In vivo imaging technology was used to optimize the modeling method and timing in Kunming mice.Subsequently,the same method was applied to C57BL/6N mice using wild-type Panc02 pancreatic cancer cells to establish orthotopic and ectopic pancreatic cancer models with intact immune function.Key parameters,including body weight,inoculation positive rate,tumor growth time,tumor volume,and pathological characteristics across different organs,were compared be-tween the orthotopic and ectopic models in C57BL/6N mice to evaluate the applicability of these models.Results Both the small animal in vivo imaging experiments in Kunming mice and the tumor growth observation in C57BL/6N mice demonstrated that the construction periods for orthotopic and ectopic pancreatic cancer models were 20 days,with survival rates exceeding 90%.The inoculation positive rates in C57BL/6N mice were 92.3%for the orthotopic model and 78.6%for the ectopic model.On day 20 post-inoculation,the tumor volumes were(117.04±109.56)mm3 for the orthotopic model and(155.68±168.73)mm3 for the ectopic model,indicating high model success rates and consistent tumor growth.HE staining revealed pathological mitotic figures and poorly differentiated tumor tissues in both models of C57BL/6N mice,with no evidence of metastasis to other organs.Conclusions Orthotopic and ectopic pancreatic cancer models in immu-nocompetent mice were successfully developed in this study,mimicking early-stage pancreatic cancer characteristics.These models pro-vide a reliable platform for screening early diagnostic biomarkers and evaluating therapeutic interventions for pancreatic cancer.

Objective This study aimed to investigate the antimicrobial resistance profiles of bacterial strains isolated from pediatric intensive care units(PICU)in China for better antimicrobial therapy.Methods Clinical isolates were collected from 17 institutions,including tertiary care children's hospitals and pediatric department of tertiary general hospitals in China from January 1,2020 to December 31,2022.Antimicrobial susceptibility testing was carried out according to a unified protocol using Kirby-Bauer method or automated systems.Results were interpreted according to the breakpoints released by the Clinical and Laboratory Standards Institute(CLSI)in 2020.Results A total of 10 688 isolates were collected,including gram-positive organisms(39.2％)and gram-negative organisms(60.8％).The top three organisms were S.aureus(13.6％,1 453/10 688),A.baumannii(10.0％,1 067/10 688),and coagulase-negative Staphylococcus(9.9％,1 058/10 688).Multi-drug resistant organisms(MDROs)were very common in children.The prevalence of methicillin-resistant Staphylococcus aureus(MRSA),carbapenem-resistant Enterobacterales(CRE),carbapenem-resistant E.coli,carbapenem-resistant K.pneumoniae(CRKP),carbapenem-resistant A.baumannii(CRAB),and carbapenem-resistant P.aeruginosa(CRPA)was 41.1％,19.4％,8.8％,30.9％,67.4％,and 28.8％,respectively.Overall,more than 50％of Enterobacteriales isolates were resistant to cephalosporins,while nearly 25％of Enterobacteriales isolates were resistant to carbapenems.MDROs were highly resistant to commonly used antibiotics.More than 80％of CRE and CRAB strains were resistant to all beta-lactam antibiotics.CRE and CRAB showed low resistance rates to tigecycline and polymyxin.CRPA showed lower resistance rates to piperacillin,beta-lactamase inhibitor combinations than the resistance rates to third and fourth generation cephalosporins.All of the Staphylococcus and Enterococcus isolates were susceptible to vancomycin and tigecycline.None of PRSP strains isolated from meningitis and nonmeningitis samples were resistant to rifampicin,vancomycin,or linezolid.The prevalence of β-lactamase-negative ampicillin-resistant(BLNAR)strains was 43.3％in Haemophilus influenzae.Conclusions MDROs were prevalent in PICU.It is necessary to establish an effective multidisciplinary team(MDT)to control the antimicrobial resistance.

Objective:To investigate the clinical value of prospective ECG-gated high-pitch protocol scanning of third generation DSCT in the diagnosis of pediatric congenital heart disease (CHD).Methods:A total of 243 children with confirmed CHD who were expected to undergo surgical treatment were prospectively collected and randomly divided evenly into 3 groups, with first group for prospective ECG-gated high-pitch scanning in third generation DSCT (Flash 3rd), second group for prospective ECG-gated high-pitch scanning in second generation DSCT (Flash 2nd) and third group for prospective sequential scanning in third generation DSCT (Sequence 3rd). The SD value and SNR of aortic root and pulmonary artery of each child were recorded. The 5-point system is adopted with subjective scoring. Based on the result of operation, the diagnosis accuracy in 3 groups was analyzed. Results:The E values in Flash 3rd, Flash 2nd and Sequence 3rd group were 0.24 (0.19, 0.27), 0.11 (0.10, 0.14) and 0.44 (0.39, 0.48) mSv ( H=207.04, P<0.05), respectively. Subjective scores of group Flash 3rd and Sequence 3rd were significantly higher than that of group Flash 2nd [4 (4, 4) vs. 4(3, 4) vs. 3(3, 3), H=124.05, P<0.05] and no difference between these two groups. SD value of aortic root and pulmonary artery of group Flash 3rd and Sequence 3rd were significantly lower than that of group Flash 2nd( H= -40.27-33.38, P<0.05). SNR of aortic root and pulmonary artery of group Flash 3rd was significantly higher than that of group Flash 2nd and Sequence 3rd ( H=-0.90-51.42, P<0.05). Diagnosis accuracy of intracardiac malformation for group Flash 2nd was significantly lower than that of Flash 3rd and Sequence 3rd (77.7%, 90.9%, 88.9%, K=9.36, P<0.05), and there was no significant difference between the latter two groups. There was no difference in diagnosis accuracy of extracardiac malformation among 3 groups (88.6%, 94.8%, 92.2%, K=3.11, P=0.21). Conclusions:The prospective ECG-gated high-pitch scanning in third generation DSCT can take into account radiation dose and image quality, which has important clinical value in the diagnosis of CHD.

Objective To prepare quercetin nanocrystals,improve their dissolution rate,and investigate the effects of different stabilizer types and ratios on the stability of nanocrystals.Methods Quercetin nanocrystals were prepared by solvent ultrasonication,and three different stabilizers(polyvinylpyrrolidone-K30,poloxamer F188 and sodium dodecyl sulfate)were compared.The particle size was used as a screening index to investigate the stability of placement,the microscopic morphology of nanocrystals was characterized by scanning electron microscopy,infrared spectroscopy and X-ray diffraction,and the mechanism of action between stabilizers and nanocrystals was discussed.Results Through experimental screening,the results showed that povidone K30 had the best stable performance,the nanocrystals were also in the form of rod crystals,and the dissolution rate of nanocrystals was significantly higher than that of active pharmaceutical ingredients.Conclusion The type and amount of stabilizer will affect the stability of nanocrystals.

Objective:To explore the value of coronary CT angiography (CCTA) in the diagnosis of vulnerable plaques using intravascular ultrasound (IVUS) as the gold standard.Methods:A retrospective analysis was conducted on the clinical and imaging data of coronary artery disease patients who underwent both IVUS and CCTA examinations at Fuwai Central China Cardiovascular Hospital from December 2017 to March 2022. Based on the IVUS results, the coronary plaques were divided into vulnerable and non-vulnerable plaque groups. Finally, 43 patients with a total of 88 coronary artery plaques were included, of which 26 were vulnerable plaques. Plaque analysis were performed on the CCTA images, including qualitative parameters such as low-density plaques (LAP), "napkin-ring" sign (NRS), spotty calcification (SC) and positive remodeling (PR), and the quantitative parameters such as minimum lumen area (MLA), total plaque volume (TPV), lesion length, volume and proportion of calcified plaque and fibrous plaque. The differences of CCTA parameters between the two groups were compared using t-test, chi-square test, and rank sum test. The association between CCTA parameters and the risk of vulnerable plaque was evaluated by logistic regression. Different CCTA parameters were used to establish qualitative, quantitative, and hybrid models, and the diagnostic efficacy of different models for vulnerable plaque was evaluated using the receiver operating characteristic (ROC) curve. Results:There were significant differences in NRS ( χ2=14.22, P<0.001), MLA ( Z=3.25, P=0.001), lesion length ( Z=-3.28, P=0.001), TPV ( Z=-2.04, P=0.041), calcified plaque volume ( Z=-2.52, P=0.012) and fibrous plaque volume ( Z=-2.10, P=0.035) between vulnerable and non-vulnerable plaque groups. The logistic regression analysis showed that NRS ( OR=9.66, 95% CI 2.36-39.54), MLA ( OR=0.76, 95% CI 0.59-0.99) and lesion length ( OR=1.03, 95% CI 1.00-1.07) were independent risk factors for vulnerable plaques. The diagnostic efficacy of the hybrid model based on CCTA parameters was superior to the qualitative model [hybrid model: area under the ROC curve (AUC)=0.82, 95% CI 0.72-0.89; qualitative model: AUC=0.68, 95% CI 0.57-0.78; Z=2.57, P=0.010]. Conclusions:CCTA parameters NRS, MLA, and lesion length are independent risk factors for coronary vulnerable plaques. The diagnostic efficacy of the hybrid model based on CCTA parameters is superior to the qualitative model for vulnerable plaques.

This study retrospectively analyzed the clinical data of four patients with malignant tumor-induced ureteral strictures admitted to our hospital. All patients successfully underwent ureteroscopic metal stent placement surgery under real-time ultrasound guidance, with a surgical duration of (64±33) minutes. Postoperatively, there was a creatinine decrease of (74±127) mmol/L. Only two cases experienced Clavien-Dindo grade I complications postoperatively. The stents were well positioned in all patients, with a postoperative hospital stay of (2.5±0.6) days. This surgical approach for malignant tumor-induced ureteral obstruction can compensate for the limitations of endoscopic visualization.