objective To observe the influence of hemodynamic changes caused by extracranial carotid stenosis on the plaque stability, and analyze the relationship of cerebral infarction classification,criminal artery stenosis degree and plaque stability to offer evidence for evalu-ating nosogenesis,clinical diagnosis,treatment and prevention of cerebral infarction. Methods CDFI,CTA were performed in 168 patients with acute cerebral infarction,some moderate and severe and occlusive carotid artery which were demonstrated by CTA and CDFI were further checked by DSA during convalescence. Totally 168 acute cerebral infarction patients were divided into 5 groups based on the criminal artery stenosis degree. To evaluate the plaque stability and flow field changes with CDFI and CTA,OCSP clinical classification and brain image clas-sification were finished according to CTA. Patients were classified into 4 subtypes,namely cortical infarction,basal ganglion infarction,corona radiata infarction and posterior infarction,according to the lesion distributions. Observe the changes of flow field and stability of plaque,and compare the relationship between different degree of stenosis and the classification of lesion of infarction. Results Among the 168 criminal arteries,there was 17. 9% of normal,22. 6% of mild stenosis,30. 9% of moderate stenosis,14. 8% of severe stenosis,and 14. 3% of occlu-sion,and the moderate stenosis proportion was the highest. When the stenosis degree was over 50%,it may lead to the changes of flow field, speeding up of blood flow,forming of turbulent flow,and increasing of plaque instability in which lipid plaque and admixture plaque was the highest. PACI is the commonest in all moderate groups. Admixture plaque is usually seen in severe stenosis and occlusion, while fibrous plaque is usually seen in mild stenosis. Conclusion Moderate carotid stenosis may lead to the increase of plaque instability as a result of the changes of flow field,and it may prone to artery-artery embolization.

Objective To analyze the imageological characteristics of intracranial vascular multiple stenosis aneurysms and to e-valuate the influence of cerebral vascular stenosis caused hemodynamic change on the aneurysm occurrence .Methods The clinical data of 30 inpatients with intracranial arterial multiple stenosis aneurysms diagnosed by CTA and DSA ,who were hospitalized due to ischemic cerebrovascular disease in the neurology department of 251 Hospital of Beijing Military Region from January 2007 to May 2012 ,were retrospectively analyzed and taken as the observation group ;contemporaneous 30 cases of aneurysm without in-tracranial and extracranial arterial stenosis admitted to the neurosurgery department were taken as the control group .The gender , age of onset ,number of aneurysms ,whether or not complicating hypertension ,diabetes ,smoking ,hyperlipemia ,plaque of extracrani-al carotid artery ,ischemic stroke and cerebral arterial abnormal development were compared between the two groups .The Logistic single factor and multi-factor correlation analysis was adopted to evaluate the correlation between the aneurysm occurrence with the hemodynamic changes caused by atherosclerotic stenosis .Results Cystic multiple aneurysms were common in the observation group ,which was up to 4 in number ,the age was more than 60 years ,the majority was complicated by hypertension ,diabetes ,hyper-lipemia ,cerebral stroke ,plaque of extracranial carotid artery and intracranial arterial multiple stenosis were common .Aneurysms mostly occurred in intracranial artery with severe stenosis .The gender differences were unobvious .The control group was domina-ted by young patients .Single aneurysm was more common without intracranial artery multiple stenosis .The occurrence rate of ca-rotid arterial plaque and cerebral stroke was lower .The partial patients had smoking ,hyperlipidemia and hypertension .The Logistic regression analysis between the two groups showed that ischemic stroke ,cerebral arterial development abnormality and atheroscle-rosis plaque of extracranial carotid artery had significant correlation .Conclusion The aneurysm occurrence is related with cerebral arterial atherosclerotic stenosis ,which becomes the important factor leading to aneurysm formation and should arouse attention to conduct early diagnosis and early treatment .

Objective To investigate the effectiveness,safety of the percutaneous transluminal angioplasty and stenting(PTAS) in the management of the vertebrobasilar stenosis.Methods From April 2003 to June 2004,the PTAS was performed in 28 patients with the vertebrobasilar stenosis.Results Among the 28 patients,the unilateral significant stenosis of the dominant vertebral artery was found in 18 patients,the bilateral stenosis of the vertebral artery in 4 patients,the tandem stenosis of the vertebral artery in 1 patient,the stenosis of the basilar artery in 2 patients.According to Mori's division,the type A occurred in 24 patients,the type B in 3 patients,the type C in 1 patient.The successful rate of stent implantation was 100% without any serious complication.Twenty-eight patients underwent PTAS with a mean pre-procedural vertebrobasilar stenosis of 81.3% and the residual stenosis was less than 10%.Over a mean 6-month follow-up in 17 patients,according to Malek's scale,the scale 1 was in 15 patients,the scale 2 in 2 patients.No restenosis was in 3 patients by the cerebral angiography.Conclusion PTAS in the management of the vertebrobasilar stenosis is a safe and effective method.Meanwhile,PTAS may alleviate the vertebrobasilar ischemia and prevent stroke of the vertebrobasilar system.

Objective:To investigate the resistance and transmission mechanism of carbapenem-resistant Enterobacterales (CRE), so as to provide the scientific evidence for the treatment and prevention of CRE infection.Methods:Seventy-six isolates of CRE isolated from Shaoxing Second Hospital between May 2016 and August 2018 were included. The isolates were re-identified by matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS). The minimum inhibitory concentrations (MICs) of colistin, tigecycline, ceftazidime-avibactam, fosfomycin and other antibacterial drugs were determined using broth microdilution or agar dilution methods. PCR and sequencing analysis were performed to detect carbapenemase encoding genes ( blaKPC, blaNDM, blaIMP, blaVIM, blaOXA-48). Pulsed field gel electrophoresis (PFGE) and multilocus sequence typing (MLST) were used to analyze homology of strains. S1-PFGE combined with Southern blot hybridization were used to locate the carbapenamase genes. Filter mating test were performed to determine the horizontal transfer ability of plasmids harboring carbapenamase genes. Results:Among the 76 isolates of CRE, 51 isolates were Klebsiella pneumoniae; 10 isolates were Escherichia coli; 15 isolates were other Enterobacterales. The 76 CREs were mainly isolated from urine, sputum and blood samples. The distribution rate of ICU was the highest (55.26%). The 76 CREs showed low resistance rates (0%, 1.33%, 18.42%) to colistin, tigecycline and ceftazidime-avibactam. The resistance rates to amikacin and fosfomycin were <45%, and the resistance rates to other drugs were >97%. The detection rate of KPC-2 carbapenemase was the highest (85.33%). The ST11 CRKP producing KPC-2 carbapenemase accounted for the highest proportion (62.75%), mainly distributed in the ICU (62.50%). Southern blot hybridization showed that blaKPC-2 was mainly located on a plasmid about 90 kb (39/63). Filter mating test showed that blaKPC, blaNDM and blaIMP could be transferred horizontally to recipient bacteria through plasmids. Conclusions:The 76 CRE isolates were only susceptible to a few antibacterial drugs, such as colistin, tigecycline and ceftazidime-avibactam. The production of KPC-2 carbapenemase was the main reason for the resistance of Enterobacterales to carbapenems. KPC-2 carbapenemase-producing ST11 Klebsiella pneumoniae was the main epidemic clone of carbapenem-resistant Klebsiella pneumoniae (CRKP). The 90 kb size plasmid was the main plasmid encoding blaKPC-2 gene. Carbapenemase genes can be transferred horizontally through plasmids. The hospital should strengthen prevention of nosocomial infections to control the clonal prevalence of CRE.

BACKGROUND:In recent years,additive manufacturing(also known as 3D printing)has gradually become the mainstream method for producing titanium alloy brackets for removable partial dentures.Heat treatment,as an important method to improve the mechanical properties of 3D printed titanium alloys,has become a current hot topic of attention.OBJECTIVE:To summarize the main heat treatment technologies currently applied to 3D printed titanium alloy specimens(including annealing,solution aging,hot isostatic pressing,and other heat treatments)and their effects on the mechanical properties and microstructure of 3D printed titanium alloy specimens,providing a theoretical basis for improving the heat treatment technology of removable partial denture titanium alloy supports.METHODS:A computer search was conducted on research materials related to 3D printed titanium alloy heat treatment in databases such as CNKI,PubMed,and ScienceDirect.The search period was from 2012 to 2023.A total of 61 articles were selected based on inclusion and exclusion criteria.RESULTS AND CONCLUSION:(1)Using conventional annealing techniques to treat 3D printed titanium alloy specimens,keeping them at 500-900 ℃ for 2-4 hours,can effectively increase the elongation of 3D printed titanium alloy specimens.(2)Compared to conventional annealing techniques,solid solution aging treatment is more complex,and the titanium alloy specimens after solid solution aging treatment exhibit outstanding yield strength and better corrosion resistance.However,the 3D printed titanium alloy specimens after solid solution aging treatment have no advantage in terms of ductility.(3)Hot isostatic pressing treatment can reduce the internal defects of 3D printed titanium alloy specimens,significantly increase the elongation of 3D printed titanium alloy specimens,and increase their fatigue life.(4)Rapid heat treatment can significantly improve the elongation of 3D printed titanium alloy specimens,and the speed is faster.In terms of elongation improvement and heat treatment efficiency,it has more advantages than conventional annealing in the past.(5)The improvement of elongation of 3D printed titanium alloy specimens by cyclic heat treatment exceeds that of conventional annealing.Cyclic heat treatment can significantly improve the grain structure of 3D printed titanium alloy specimens,but the heat treatment time is too long and the efficiency is low.

Objective To investigate the protective effect of adult human liver-derived stem cell exosomes (HLSC-exo) intravenously injected at different time points against acute liver injury induced by concanavalin A (ConA) in mice. Methods HLSC-exo was extracted by differential centrifugation. Western blot was used to measure the expression of the marker proteins CD9 and CD63, and nanoparticle tracking analysis was used to investigate particle size distribution. A total of 56 male C57BL/6 mice were randomly divided into blank control group, ConA model group, and HLSC-exo treatment group. The ConA model group and the HLSC-exo treatment group were further divided into 3-, 6-, and 12-hour subgroups according to the interval between phosphate buffer or HLSC-exo injection and ConA injection. The serum levels of alanine aminotransferase (ALT), aspartate aminotransferase (AST), tumor necrosis factor-α (TNF-α), and interleukin-10 (IL-10) were measured, and the gross morphology and histopathology of the liver were compared between groups. A one-way analysis of variance was used for comparison of continuous data between multiple groups, and the least significant difference t -test was used for further comparison between two groups. Results HLSC-exo was a membranous vesicle with a diameter of 90-110 nm, with a clear saucer-like structure under an electron microscope and marked expression of its specific marker proteins CD9 and CD63. In the blank control group, the levels of ALT and AST were 31.81±6.74 U/L and 69.75±8.30 U/L, respectively. Compared with the blank control group, the 3-, 6-, and 12-hour ConA model groups had significant increases in the levels of ALT and AST (all P < 0.001); compared with the 3-and 6-hour ConA model groups, the 3-and 6-hour HLSC-exo treatment groups had significant reductions in the levels of ALT and AST (225.58±115.59 U/L vs 1989.32±347.67 U/L, 1174.71±203.30 U/L vs 2208.33±349.96 U/L, 303.53±126.68 U/L vs 2534.27±644.72 U/L, 1340.70±262.56 U/L vs 2437.13±288.13 U/L, all P < 0.001); compared with the 6-hour HLSC-exo treatment group, the 3-hour HLSC-exo treatment group had significantly greater reductions ( P < 0.001). In the blank group, the levels of IL-10 and TNF-α were 313.51±10.97 pg/ml and 476.05±7.31 pg/ml, respectively. Compared with the blank control group, the 3-, 6-, and 12-hour ConA model groups had a significant reduction in the level of IL-10 (all P < 0.001); compared with the 3-and 6-hour ConA model groups, the 3-and 6-hour HLSC-exo treatment groups had a significant increase in the level of IL-10(331.61±10.46 pg/ml vs 266.20±8.15 pg/ml, 288.13±10.74 pg/ml vs 264.41±9.12 pg/ml, both P < 0.001); compared with the 6-hour HLSC-exo treatment group, the 3-hour HLSC-exo treatment group had a significantly greater increase ( P < 0.001). Compared with the blank control group, the 3-, 6-, and 12-hour ConA model groups had a significant increase in the level of TNF-α (all P < 0.001); compared with the 3-and 6-hour ConA model groups, the 3-and 6-hour HLSC-exo treatment groups had a significant reduction in the level of TNF-α (478.26±12.99 pg/ml vs 551.31±17.70 pg/ml, 515.58±7.18 pg/ml vs 556.21±11.15 pg/ml, both P < 0.001); compared with the 6-hour HLSC-exo treatment group, the 3-hour HLSC-exo treatment group had a significantly greater reduction ( P < 0.001). Compared with the 3-and 6-hour ConA model groups in terms of the gross morphology and histopathology of the liver, the 3-and 6-hour HLSC-exo treatment groups had a significant reduction in the degree of hepatocyte necrosis, and the 3-hour HLSC-exo treatment group had a basically complete lobular structure, with sporadic spotty necrosis; the 12-hour HLSC-exo treatment group had no significant improvement in hepatocyte necrosis compared with the 12-hour ConA model group. Conclusion Intravenous injection of adult HLSC-exo can alleviate acute liver injury induced by ConA in mice, and injection at 3 hours in advance has the most significant protective effect. Regulation of cytokines is one of the important mechanisms for HLSC-exo to alleviate liver injury.