BACKGROUND:Medium-and large-diameter polytetrafluoroethylene artificial blood vessels have been widely used in clinical practice.However,most of the products were imported from other countries.Small-diameter porous polytetrafluoroethylene vessels are easy to form thrombosis and intimal hyperplasia,resulting in an extremely low long-term patency rate,which is difficult to fulfill clinical requirements. OBJECTIVE:To review and summarize the research progress of polytetrafluoroethylene in the field of artificial blood vessels,which can provide a reference for the functional modification of small-diameter polytetrafluoroethylene artificial blood vessels and the improvement of their long-term patency rate. METHODS:The relevant articles published from October 2022 to March 2023 in CNKI,Web of Science,Wiley Online Library,SpringerLink,Science Direct and IOP Science databases were searched by the first author.The search terms in Chinese were"porous polytetrafluoroethylene,vascular graft,electrospinning,medical application,functional modification".The search terms in English were"ePTFE,porous polytetrafluoroethylene,vascular graft,electrospinning,medical application,functional modification".All the articles about the preparation and modification of polytetrafluoroethylene artificial blood vessels were retrieved. RESULTS AND CONCLUSION:The preparation and functional modification of porous polytetrafluoroethylene artificial blood vessels were still research hotspots and difficult problems.From the research progress in and outside China in recent years,the preparation of porous polytetrafluoroethylene artificial blood vessels mainly adopted the rapid thermal stretching method,but the preparation of polytetrafluoroethylene artificial blood vessels by electrospinning was a promising new method.By analyzing and summarizing different functional modification methods,it was found that the long-term patency rate of porous polytetrafluoroethylene artificial blood vessels had been improved.However,the functional modification of small-diameter polytetrafluoroethylene artificial blood vessels still needed further exploration and optimization.

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 perform acceptance test and performance assessment for Siemens Biograph Vision 600 positron-emission tomography/computed tomography(PET/CT)according to the national health industry standard WS 817-2023.Methods:Spatial resolution,sensitivity,scatter fraction,count loss and random coincidence,correction accuracy of count loss and random coincidence,time-of-flight(TOF)resolution of the PET component within the PET/CT system were tested through the measurement program(NU2-2018)of National Electrical Manufacturers Association(NEMA),which was installed inside of the equipment,in accordance with the requirement of national health industry standard WS 817-2023.The PET/CT registration accuracy was measured through Gantry_offset acquisition program that was built into the equipment.Results:The transversely and axially spatial resolutions of Biograph Vision 600 PET/CT were respectively 3.69 mm and 4.10 mm at 1 cm away from the center of visual field,and were respectively 4.26 mm and 4.89 mm at 10 cm away from the center of visual field,and were respectively 4.68 mm and 4.89 mm at 20 cm away from the center of visual field.The sensitivity of 10 cm away from center and radial of visual field were respectively 16.12 kcps/MBq and 16.00 kcps/MBq.The peak value of noise equivalent count rate(NECR)was 281.60 kcps,and the corresponding radioactivity concentration of peak value was 30.69 kBq/ml.The NECR peak value,scatter fraction and maximum value of the error of relative count rate were respectively 38.17% and 4.0%.The TOF resolution was 209.87 ps when the radioactivity concentration was 5.3 kBq/mL.The registration accuracy values of Biograph Vision 600 PET/CT were 0.347 mm,-0.226 mm and 3.659 mm at the directions of x,y and z axis.Conclusion:It is feasible to perform the acceptance test according to the WS 817-2023 standard through uses the NEMA NU2-2018 standard measurement program that is installed inside of the equipment.The performance indicators can meet requirement of standard as the current national standard GB/T 18988.1-2013 and the health industry standard WS 817-2023 that will being implemented in the test of Biograph Vision 600 PET/CT,which can pass acceptance.

Objective To analyze the prognosis and influencing factors in patients with radioiodine-refractory differentiated thyroid cancer (RAIR-DTC). Methods A retrospective analysis was conducted on 52 patients with RAIR-DTC who underwent ineffective ¹³¹I therapy at the Department of Nuclear Medicine, Cancer Hospital, Chinese Academy of Medical Sciences from October 2016 to January 2020. Patients were categorized into progression and stable groups based on disease progression within five years post-treatment. Differences between groups were analyzed using chi-square test and logistic regression. Independent prognostic risk factors were identified using a Cox proportional hazards model. The Kaplan-Meier method with log-rank test was used to evaluate the impact of treatment on the prognosis of the progression group. Results The 3-year and 5-year survival rates of the 52 patients with RAIR-DTC were 88.5% and 73.1%, respectively. In the progression group, the rates were 81.8% and 57.6%. In the stable group, the rates were 100% and 100%. There were significant differences between the two groups in terms of age, presence of extrathyroidal extension, and the initial ¹³¹I treatment dose (P < 0.05). Univariate analysis indicated that the age, pre-ablation stimulated thyroglobulin level before the first ¹³¹I treatment, the neutrophil-to-lymphocyte ratio before the first treatment, and the sites of recurrence and metastasis were significantly associated with overall survival (P < 0.05). Multivariate analysis showed that age > 55 years (HR=12.40, 95% CI= 2.09-73.57, P=0.001) and distant metastasis (HR=24.47, 95% CI=4.17-143.75, P < 0.001) were independent risk factors for poor prognosis. Kaplan-Meier curve analysis showed that local surgery and/or targeted therapy significantly prolonged progression-free survival in the progression group (P < 0.001). Conclusion The prognosis for RAIR-DTC is poor, with advanced age and distant metastasis significantly associated with unfavorable outcomes. In elderly patients and those with extrathyroidal invasion, the treatment dose during initial ¹³¹I therapy may be appropriately increased to delay disease progression. For patients with disease progression, prompt local surgical intervention and/or targeted therapy is recommended.

Objective To analyze the prognosis and influencing factors in patients with radioiodine-refractory differentiated thyroid cancer (RAIR-DTC). Methods A retrospective analysis was conducted on 52 patients with RAIR-DTC who underwent ineffective ¹³¹I therapy at the Department of Nuclear Medicine, Cancer Hospital, Chinese Academy of Medical Sciences from October 2016 to January 2020. Patients were categorized into progression and stable groups based on disease progression within five years post-treatment. Differences between groups were analyzed using chi-square test and logistic regression. Independent prognostic risk factors were identified using a Cox proportional hazards model. The Kaplan-Meier method with log-rank test was used to evaluate the impact of treatment on the prognosis of the progression group. Results The 3-year and 5-year survival rates of the 52 patients with RAIR-DTC were 88.5% and 73.1%, respectively. In the progression group, the rates were 81.8% and 57.6%. In the stable group, the rates were 100% and 100%. There were significant differences between the two groups in terms of age, presence of extrathyroidal extension, and the initial ¹³¹I treatment dose (P < 0.05). Univariate analysis indicated that the age, pre-ablation stimulated thyroglobulin level before the first ¹³¹I treatment, the neutrophil-to-lymphocyte ratio before the first treatment, and the sites of recurrence and metastasis were significantly associated with overall survival (P < 0.05). Multivariate analysis showed that age > 55 years (HR=12.40, 95% CI= 2.09-73.57, P=0.001) and distant metastasis (HR=24.47, 95% CI=4.17-143.75, P < 0.001) were independent risk factors for poor prognosis. Kaplan-Meier curve analysis showed that local surgery and/or targeted therapy significantly prolonged progression-free survival in the progression group (P < 0.001). Conclusion The prognosis for RAIR-DTC is poor, with advanced age and distant metastasis significantly associated with unfavorable outcomes. In elderly patients and those with extrathyroidal invasion, the treatment dose during initial ¹³¹I therapy may be appropriately increased to delay disease progression. For patients with disease progression, prompt local surgical intervention and/or targeted therapy is recommended.

Objective To explore the correlation value of high-resolution MRI on the cause,location and degree of nerve root com-pression and clinical symptoms of lumbar intervertebral foramen stenosis.Methods Patients with sciatic neuralgia underwent con-ventional MRI examination of the lumbar spine before treatment.MRI thin layer(1 mm)intervertebral disc axial scan was performed on patients with suspected L4/L5 and L5/S1 intervertebral foramen stenosis,and the value of conventional MRI and high-resolution MRI on intervertebral foramen stenosis location,etiology and Elisabeth typing was compared and analyzed.Intervertebral foramen mor-phometric indicators,nerve root length and short diameter were measured on high-resolution MRI post-processed images and their correlation with visual analogue scale(VAS)scores of clinical symptoms was analyzed.Results Sixty-one patients were effectively diagnosed with intervertebral foramen stenosis and nerve root compression after surgery or conservative treatment.The diagnosis rate of conventional MRI for the cause of intervertebral foramen stenosis was 75.4％,and the diagnosis rate of high-resolution MRI post-processed was 91.8％.The Elisabeth typing of lumbar intervertebral foramen stenosis was positively correlated with clinical symp-toms,while the nerve root short diameter and peri-nerve fat space area were negatively correlated with VAS score.Conclusion High-resolution MRI is significantly better than conventional MRI for the diagnosis of nerve root compression in intervertebral fora-men stenosis.It visually shows the location,cause and degree of nerve root compression,which can better guide the clinical and accu-rate minimally invasive surgery.

Objective:To explore with healthy adults any effect on postural control of transcranial direct current stimulation (tDCS) applied over the left dorsolateral prefrontal cortex (L-DLPFC) and the primary motor cortex (M1).Methods:Eighteen healthy adults received 3 tDCS stimulation protocols sequentially applied to either the left dorsolateral prefrontal cortex alone, the left dorsolateral prefrontal cortex and the bilateral primary motor cortex simultaneously or sham stimulation, respectively. Each intervention protocol lasted for 20 minutes with a total current intensity of less than 4mA, with a 7-day interval between the each stimulation protocol. Single-task and dual-task walking and balance tests were administered before and after each stimulation protocol, followed by statistical analysis.Results:The results of the single-task gait function testing showed that the change in step width before and after single-target tDCS stimulation was (-0.511±1.072)cm, significantly better than with sham stimulation. In the dual-task gait function tests the change in step width after single-target tDCS stimulation was (-0.511±1.072)cm, significantly better than in the other two groups.Conclusions:Stimulating only the dorsolateral prefrontal cortex can effectively regulate cognitive-motor postural control. Multi-target tDCS offers no particular advantage.

Patients with severe trauma require an extremely timely treatment and transfusion plays an irreplaceable role in the emergency treatment of such patients. An increasing number of evidence-based medicinal evidences and clinical practices suggest that patients with severe traumatic bleeding benefit from early transfusion of low-titer group O whole blood or hemostatic resuscitation with red blood cells, plasma and platelet of a balanced ratio. However, the current domestic mode of blood supply cannot fully meet the requirements of timely and effective blood transfusion for emergency treatment of patients with severe trauma in clinical practice. In order to solve the key problems in blood supply and blood transfusion strategies for emergency treatment of severe trauma, Branch of Clinical Transfusion Medicine of Chinese Medical Association, Group for Trauma Emergency Care and Multiple Injuries of Trauma Branch of Chinese Medical Association, Young Scholar Group of Disaster Medicine Branch of Chinese Medical Association organized domestic experts of blood transfusion medicine and trauma treatment to jointly formulate Chinese expert consensus on blood support mode and blood transfusion strategies for emergency treatment of severe trauma patients ( version 2024). Based on the evidence-based medical evidence and Delphi method of expert consultation and voting, 10 recommendations were put forward from two aspects of blood support mode and transfusion strategies, aiming to provide a reference for transfusion resuscitation in the emergency treatment of severe trauma and further improve the success rate of treatment of patients with severe trauma.

Objective:To investigate the spatial resolution and image quality of positron emission tomography and X-ray computed tomography (PET/CT) based on the next-generation silicon photomultiplier (SiPM) and the conventional photomultiplier tube (PMT) and to explore the effects of different PET photoelectric transducers (PMT and SiPM) and the Q. Clear algorithm on the spatial resolution, quantitative accuracy, and image quality of PET/CT.Methods:GE Discovery Elite PET/CT (PMT PET/CT) and GE Discovery Meaningful Insights (MI) PET/CT (SiPM PET/CT) were employed to scan the elliptical resolution phantom and NEMA NU2-2018 image quality phantom. Using the OSEM+ PSF+ TOF (VPFX-S) algorithm, image reconstruction was performed based on raw data of both phantoms. For the MI-acquired phantom data, additional reconstructions were conducted using the Q. Clear algorithm, with β values ranging from 150 to 550 and an increment of 100. For the elliptical resolution phantom, the radial, tangential, and axial full-width at half-maximum (FWHM) values of five line sources in three slices were calculated and averaged. For the image quality phantom, the recovery coefficient (RC), contrast recovery coefficient (CRC), contrast-to-noise ratio (CNR), percentage of background variability (PBV), background coefficient of variability (BCV) of the spheres, as well as the residual error (RE) of lung inserts at different image slices, were calculated.Results:Compared to Elite, MI (VPFX-S) showed decreases in the radial, tangential, and axial FWHM of 4.25%-13.58%, 7.00%-13.22%, and 6.02%-36.14%, respectively; no significant difference in RCmax for the spheres; increases in spheres′ CRC and CNR of 10.17%-38.89% and 38.31%-94.95%, respectively, and decreases in spheres′ PBV and BCV of 26.20%-33.82% and 31.29%-35.97%, respectively. When compared to MI (VPFX-S), MI (Q.Clear) showed decreases in the radial, tangential, and axial FWHM of 6.49%-45.02%, 7.80%-35.60%, and 13.31%-36.80%, respectively; an increase in spheres′ CNR of 38.31%-94.95%; decreases in spheres′ PBV and BCV of 26.20%-33.82% and 6.64%-10.31%, respectively, and no significant difference in spheres′ RC. With an increase in the β value, the CNR, RE, and FWHM in radial, tangential, and axial directions derived from MI (Q.Clear) increased, while RC, CRC, PBV, and BCV decreased. Conclusions:Under image reconstruction using VPFX-S, the next-generation SiPM PET/CT exhibits elevated spatial resolution, hot lesion contrast, detectability, and background noise compared to the PMT PET/CT. Compared to OSEM, the Q. Clear algorithm improves spatial resolution, quantitative accuracy, and image quality, with such improvement related to the β value. The β value affects the outcomes of the Q. Clear algorithm, especially the maximum quantitative value of small lesions. This is particularly important for improving clinical diagnostic capabilities.

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.