Objective:To investigate whether ultra-high dose rate (FLASH) irradiation can reduce radiation-induced intestinal injuries of mice compared to conventional dose rate (CONV) irradiation.Methods:Both FLASH and CONV irradiation were delivered with electron beam, with dose rates of 750 Gy/s and 0.5G y/s, respectively. A total of 105 mice were randomly divided into groups using a simple randomization method. Twenty-one mice were selected for weight observation, 7 mice in each group. After 9 Gy FLASH and CONV irradiation on the abdomen, the weight changes of mice were measured every other day, and compared among three groups. Twenty-four mice were selected for pathological examination including 5 mice in the control group. Three-and-a-half-day days after 12 Gy FLASH ( n=10) and CONV irradiation ( n=9) on the abdomen, the intestines of the mice were taken. Pathological sections were stained with hematoxylin-eosin (HE) to compare the number and percentage of regenerated crypts of the small intestine between two groups. After 12 Gy FLASH ( n=10) and CONV irradiation ( n=10) on the abdomen, the survival of 20 mice was observed. After FLASH using 4.5 Gy×2 times ( n=10) and CONV irradiation at 9 Gy×1 time ( n=10) on the abdomen, the weight changes were observed. After FLASH using 6 Gy×2 times ( n=10) and CONV irradiation at 12 Gy×1 time ( n=10) on the abdomen, the survival of mice was observed. The time interval between two irradiation was 1 min. EBT3 film was employed to monitor the actual exposure dose of the mice. The variables conforming to normal distribution were expressed by Mean±SD. Inter group comparison was performed by independent t-test. The survival of mice among different groups was compared by log-rank test. Results:After 9 Gy of abdominal irradiation, the mean weight of mice in the FLASH group was significantly higher than that in the CONV group. The weight of mice in the FLASH and CONV groups was (19.8±0.8) g and (18.0±1.8)g ( P=0.036) at 7 days after irradiation, (22.0±1.0)g and (21.2±0.5)g ( P=0.075) at 15 days after irradiation, and (24.2±1.4)g and (22.0±1.2)g ( P=0.012) at 25 days after irradiation, respectively. After 12 Gy irradiation, the mean survival of mice in FLASH and CONV groups was 4 days and 4.7 days ( P=0.029). After 12 Gy total abdominal irradiation, the mean number of intestinal regenerative crypts in the FLASH and CONV groups was 2.9/mm and 1.2/mm ( P=0.041), and the percentage of intestinal regenerative crypts was 34.1% and 14.1%, respectively. The survival of mice irradiated by FLASH using 6 Gy×2 times was longer compared with that of mice after CONV irradiation at 12 Gy×1 time. The weight of mice after 4.5 Gy×2 times irradiation was higher than that of mice after CONV irradiation at 9 Gy×1 time. Conclusion:Weight, survival and the number of intestinal regenerative crypts in the FLASH group are higher than those in the CONV group after irradiation, indicating that radiation-induced intestinal injury caused by FLASH irradiation is slighter than that of CONV irradiation.

Objective:To investigate the clinical efficacy of 3D printed metal augment or tibial prosthesis for reconstruction of large bone defects in total knee arthroplasty (TKA) and knee revision surgery.Methods:A total of 7 patients (7 knees) with TKA or knee revision who were admitted to the Department of Orthopaedics of the Second Affiliated Hospital of Zhejiang University School of Medicine with large bone defects from July 2018 to December 2023 were retrospectively analyzed, including 4 patients with TKA and 3 patients with knee revision. There were 3 males and 4 females, aged 58.7±7.6 years (range, 54-68 years), 3 patients with left knee and 4 patients with right knee. All the patients had bone defects in the knee joint (AORI type III), 2 cases had bone defects only in the femur, 4 cases had bone defects only in the tibia, and 1 case had bone defects in both the tibia and femur, which were treated with personalized reconstruction using 3D printing. Hip-knee-ankle angles, American Knee Society score (KSS) before and after surgery were compared, and postoperative complications were observed.Results:All patients successfully completed the operation, and the operation time was 189.3±35.5 min (range, 125-240 min). Complex TKA was performed in 4 cases with surgical times of 175, 195, 210, and 240 min, and revision surgery was performed in 3 cases with surgical times of 125, 180, and 200 min, respectively. Intraoperative blood loss was 114±24.4 ml (range, 100-150 ml). Five cases used 3D printed metal augment, and two used 3D printed one-piece tibial components. All patients were followed up for 2, 2, 5, 6, 7, 20, 57 months, respectively. The KSS of the five patients at 3 months postoperatively were 56, 61, 66, 56, and 56 points, respectively, greater than the preoperative scores of 35, 44, 36, 27, and 41 points. The KSS functional scores of the five patients at 3 months postoperatively were 45, 45, 45, 30, and 45 points, respectively, which were greater than the preoperative scores of 30, 30, 15, 20, and 20 points. The hip-knee-ankle angle was 181.8°±3.4° (range, 177.9° to 188.0°) at the final follow-up and 175.8°±12.4° (range, 153.3° to 192.1°) before surgery, with no significant difference ( t=-1.230, P=0.242). At the final follow-up, the 3D printed component was well integrated with the bone surface, the prosthesis was securely positioned, and the force lines of the lower limbs were normal. There were no postoperative complications such as poor wound healing, infection, fat liquefaction, nerve injury, deep vein thrombosis of lower limbs, knee joint stiffness, periprosthesis infection and loosening. Conclusion:Using 3D printed metal augment or tibial prosthesis to reconstruct the huge bone defect in TKA and revision has a satisfactory early clinical effect, satisfactory joint function and good surgical safety.

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 explore the effectiveness of high-definition diffusion weighted imaging(DWI)sequence combined with T1 WI-fat suppression(FS)dynamic contrast enhancement(DCE)sequence for preoperative T-stage of rectal cancer by using 3.0T MRI standardized scanning.Methods A retrospective analysis was conducted on MRI images of 57 patients with rectal cancer confirmed by pathology.Before surgery,the patients underwent 3.0T MRI standardized rectal cancer scan methods,including routine sequence,high-definition DWI sequence,and T1 WI-FS DCE sequence,etc.Then two experienced physicians evaluated the T-stage of preoperative rectal cancer through high-definition DWI(transverse and sagittal sections)and T1 WI-FS DCE sequences in the double-blind method.Using the postoperative pathological results of rectal cancer as the"gold standard",two sequences were combined to evaluate the accuracy,sensitivity,and specificity of rectal cancer T-stage.Results Among the 57 cases,there were 9 cases of upper rectal cancer,39 cases of middle rectal cancer,and 9 cases of lower rectal cancer.The accuracy rates of preoperative T-stage diagnosis for rectal cancer by two evaluator were both 85.7％(6/7)in T1 stage,88.2％(15/17)and 94.1％(16/17)in T2 stage,96.9％(31/32)and 93.8％(30/32)in T3 stage,and both 100.0％(1/1)in T4 stage.For evaluator 1,the sensitivity and specificity of the rectal cancer T-stage diagnosis were 96.1％and 83.3％,and for evaluator 2 were 94.1％and 83.3％,respectively.For rectal cancer MRI diagnosis,the accuracy rates and sensitivity were higher when combining the high-definition DWI sequence and T1 WI-FS DCE sequence,compared with a single high-definition DWI sequence or T1 WI-FS DCE sequence,and the difference was statistically significant.The average preoperative apparent diffusion coefficient(ADC)value of rectal cancer was compared between the corresponding postoperative pathological T1 to T4 stage groups,and the difference was statistically significant.Conclusion The combination of high-definition DWI sequence and T1 WI-FS DCE sequence improves the accuracy of rectal cancer T-stage,providing assistance for personalized clinical treatment.

Alzheimer's disease is a serious neurodegenerative disease without effective treatment. In recent years, researchers have tried to treat Alzheimer's disease with low-dose radiation therapy (LDRT) and have made some progress in animal models and clinical trials. Current studies have shown that LDRT can improve cognitive function in Alzheimer's patients by reducing β amyloid plaque deposition and reducing inflammation levels in central nervous system. In this review, we present the current preclinical and clinical studies, propose the possible mechanisms of LDRT in Alzheimer's disease, and discuss challenges in the planning of future trials.

5-Hydroxytryptamine(5-HT)type 3 receptor(5-HT3R)is the only type of ligand-gated ion channel in the 5-HT receptor family.Through the high permeability of Na+,K+,and Ca2+ and activation of subsequent voltage-gated calcium channels(VGCCs),5-HT3R induces a rapid increase of neuronal excitability or the release of neurotransmitters from axon terminals in the central nervous system(CNS).5-HT3Rs are widely expressed in the medial prefrontal cortex(mPFC),amygdala(AMYG),hippocampus(HIP),periaqueductal gray(PAG),and other brain regions closely associated with anxiety reactions.They have a bidirectional regulatory effect on anxiety reactions by acting on different types of cells in different brain regions.5-HT3Rs mediate the activation of the cholecystokinin(CCK)system in the AMYG,and the γ-aminobutyric acid(GABA)"disinhibition"mechanism in the prelimbic area of the mPFC promotes anxiety by the activation of GABAergic intermediate inhibitory neurons(IINs).In contrast,a 5-HT3R-induced GABA"disinhibition"mechanism in the infralimbic area of the mPFC and the ventral HIP produces anxiolytic effects.5-HT2R-mediated regulation of anxiety reactions are also activated by 5-HT3R-activated 5-HT release in the HIP and PAG.This provides a theoretical basis for the treatment of anxiety disorders or the production of anxiolytic drugs by targeting 5-HT3Rs.However,given the circuit specific modulation of 5-HT3Rs on emotion,systemic use of 5-HT3R agonism or antagonism alone seems unlikely to remedy anxiety,which deeply hinders the current clinical application of 5-HT3R drugs.Therefore,the exploitation of circuit targeting methods or a combined drug strategy might be a useful developmental approach in the future.

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.

Objective:To report the results of national surveillance on the distribution and antimicrobial resistance profile of clinical bacterial isolates from bloodstream infections in China in 2021.Methods:The clinical bacterial strains isolated from blood culture from member hospitals of Blood Bacterial Resistant Investigation Collaborative System (BRICS) were collected during January 2021 to December 2021. Antibiotic susceptibility tests were conducted by agar dilution or broth dilution methods recommended by Clinical Laboratory Standards Institute (CLSI). WHONET 5.6 was used to analyze data.Results:During the study period, 11 013 bacterial strains were collected from 51 hospitals, of which 2 782 (25.3%) were Gram-positive bacteria and 8 231 (74.7%) were Gram-negative bacteria. The top 10 bacterial species were Escherichia coli (37.6%), Klebsiella pneumoniae (18.9%), Staphylococcus aureus (9.8%), coagulase-negative Staphylococci (6.3%), Pseudomonas aeruginosa (3.6%), Enterococcus faecium (3.6%), Acinetobacter baumannii (2.8%), Enterococcus faecalis (2.7%), Enterobacter cloacae (2.5%) and Klebsiella spp (2.1%). The prevalence of methicillin-resistant Staphylococcus aureus (MRSA) and methicillin-resistant coagulase-negative Staphylococcus aureus were 25.3% and 76.8%, respectively. No glycopeptide- and daptomycin-resistant Staphylococci was detected; more than 95.0% of Staphylococcus aureus were sensitive to ceftobiprole. No vancomycin-resistant Enterococci strains were detected. The rates of extended spectrum B-lactamase (ESBL)-producing isolated in Escherichia coli, Klebsiella pneumoniae and Proteus mirabilis were 49.6%, 25.5% and 39.0%, respectively. The prevalence rates of carbapenem-resistance in Escherichia coli and Klebsiella pneumoniae were 2.2% and 15.8%, respectively; 7.9% of carbapenem-resistant Klebsiella pneumoniae was resistant to ceftazidime/avibactam combination. Ceftobiprole demonstrated excellent activity against non-ESBL-producing Escherichia coli and Klebsiella pneumoniae. Aztreonam/avibactam was highly active against carbapenem-resistant Escherichia coli and Klebsiella pneumoniae. The prevalence rate of carbapenem-resistance in Acinetobacter baumannii was 60.0%, while polymyxin and tigecycline showed good activity against Acinetobacter baumannii (5.5% and 4.5%). The prevalence of carbapenem-resistance in Pseudomonas aeruginosa was 18.9%. Conclusions:The BRICS surveillance results in 2021 shows that the main pathogens of blood stream infection in China are gram-negative bacteria, in which Escherichia coli is the most common. The MRSA incidence shows a further decreasing trend in China and the overall prevalence of vancomycin-resistant Enterococci is low. The prevalence of Carbapenem-resistant Klebsiella pneumoniae is still on a high level, but the trend is downwards.

The bacterial ATP-competitive GyrB/ParE subunits of type II topoisomerase are important anti-bacterial targets to treat super drug-resistant bacterial infections. Herein we discovered novel pyrrolamide-type GyrB/ParE inhibitors based on the structural modifications of the candidate AZD5099 that was withdrawn from the clinical trials due to safety liabilities such as mitochondrial toxicity. The hydroxyisopropyl pyridazine compound 28 had a significant inhibitory effect on Gyrase (GyrB, IC₅₀ = 49 nmol/L) and a modest inhibitory effect on Topo IV (ParE, IC₅₀ = 1.513 μmol/L) of Staphylococcus aureus. It also had significant antibacterial activities on susceptible and resistant Gram-positive bacteria with a minimum inhibitory concentration (MIC) of less than 0.03 μg/mL, which showed a time-dependent bactericidal effect and low frequencies of spontaneous resistance against S. aureus. Compound 28 had better protective effects than the positive control drugs such as DS-2969 ( 5) and AZD5099 ( 6) in mouse models of sepsis induced by methicillin-resistant Staphylococcus aureus (MRSA) infection. It also showed better bactericidal activities than clinically used vancomycin in the mouse thigh MRSA infection models. Moreover, compound 28 has much lower mitochondrial toxicity than AZD5099 ( 6) as well as excellent therapeutic indexes and pharmacokinetic properties. At present, compound 28 has been evaluated as a pre-clinical drug candidate for the treatment of drug-resistant Gram-positive bacterial infection. On the other hand, compound 28 also has good inhibitory activities against stubborn Gram-negative bacteria such as Escherichia coli (MIC = 1 μg/mL), which is comparable with the most potent pyrrolamide-type GyrB/ParE inhibitors reported recently. In addition, the structure-activity relationships of the compounds were also studied.

BACKGROUND: Hepatitis B surface antigen (HBsAg) clearance is vital for a functional cure of hepatitis B virus (HBV) infection. However, the incidence and predictors of HBsAg seroclearance in patients co-infected with HBV and human immunodeficiency virus (HIV) remain largely unknown in Guangdong, China. METHODS: Between 2009 and 2019, patients co-infected with HBV/HIV undergoing antiretroviral therapy (ART) in Guangzhou Eighth People's Hospital affiliated to Guangzhou Medical University were retrospectively reviewed with the endpoint on December 31, 2020. The incidence and risk factors for HBsAg seroclearance were evaluated using Kaplan-Meier and multivariate Cox regression analyses. RESULTS: A total of 1550 HBV/HIV co-infected patients were included in the study, with the median age of 42 years and 86.0% (1333/1550) males. Further, 98.3% (1524/1550) received ART containing tenofovir disoproxil fumarate (TDF) plus lamivudine (3TC). HBV DNA was examined in 1283 cases at the last follow-up. Over the median 4.7 years of follow-up, 8.1% (126/1550) patients achieved HBsAg seroclearance, among whom 50.8% (64/126) obtained hepatitis B surface antibody, 28.1% (137/488) acquired hepatitis B e antigen seroconversion, and 95.9% (1231/1283) undetectable HBV DNA. Compared with patients who maintained HBsAg positive, cases achieving HBsAg seroclearance showed no differences in age, gender, CD4 + T cell count, alanine aminotransferase (ALT) level, or fibrosis status; however, they presented lower HBV DNA levels, lower HBsAg levels, and higher rates of HBV genotype B at the baseline. Multivariate analysis showed that baseline HBsAg <1500 cutoff index (COI) (adjusted hazard ratio [aHR], 2.74, 95% confidence interval [95% CI]: 1.48-5.09), ALT elevation >2 × upper limit of normal during the first six months after receiving ART (aHR, 2.96, 95% CI: 1.53-5.77), and HBV genotype B (aHR, 3.73, 95% CI: 1.46-9.59) were independent predictors for HBsAg seroclearance (all P <0.01). CONCLUSIONS Long-term TDF-containing ART has high anti-HBV efficacy including relatively high overall HBsAg seroclearance in HBV/HIV co-infected patients. Lower baseline HBsAg levels, HBV genotype B, and elevated ALT levels during the first six months of ART are potential predictors of HBsAg seroclearance.
Male ; Humans ; Adult ; Hepatitis B Surface Antigens ; Hepatitis B virus/genetics* ; HIV Infections/drug therapy* ; HIV ; DNA, Viral ; Incidence ; Coinfection/drug therapy* ; Retrospective Studies ; Tenofovir/therapeutic use* ; Lamivudine/therapeutic use* ; Hepatitis B, Chronic/drug therapy*