Objective: To elucidate the expression level and transcript structure of the CD36 gene in megakaryocytes cultured in vitro. Methods: Using umbilical cord blood CD34 hematopoietic stem cells as the starting point, megakaryocytic lineage cells were directionally cultured in vitro using different combinations of cytokines. Total cell RNA was extracted from cultures at 0 d, 7 d, and 12 d, and megakaryocyte RNA was extracted from CD41a-sorted cells after 14 d and 18 d of culture. RNA-NGS sequencing technology was used to analyze the RNA gene expression profiles across the five culture periods and further investigate CD36 gene expression. Results: The number of megakaryocytes generated in the TPO (100 ng/mL) group [(2.2±0.02)×10 /mL] was significantly higher than that in the other five groups. A total of 22 066 expressed genes were detected in the RNA of the five culture periods, and gene expression levels at each time point were correlated with the culture timeline. CD36 gene expression increased with culture time, with FPKM values for CD36 expression in the megakaryocytic lineage at 14 d and 18 d being 18.35 and 101.85, respectively, which were much lower than those for ITGA2B and ITGB3 genes but slightly higher than that for CD109 gene in the megakaryocytic lineage. The longest transcript of CD36 in the 18 d megakaryocytic lineage was 3.8 kb, encompassing all sequence of exons E3 to E14 and a partial sequence of E15. Conclusion: This is the first report on the expression level and transcript structure of the CD36 gene in megakaryocytes cultured in vitro, providing fundamental data for research on the expression and regulation of the CD36 gene in the megakaryocytic lineage.

AIM: To compare the refractive prediction accuracy of 7 intraocular lens(IOL)calculation formulas in the cataract eyes with short axial length(AL)at different corneal curvatures and anterior chamber depth(ACD), and analyze relevant influencing factors contributing to prediction errors.METHODS: A retrospective analysis was performed for 125 patients(125 eyes)with a short AL, who received cataract phacoemulsification at Shenyang He Eye Specialist Hospital from November 2020 to December 2021. According to the keratometry(Km), they were divided into low flat Km group(≤45.5 D), medium and high Km group(45.5 D

The incidence of knee osteoarthritis(KOA)is in-creasing year by year,seriously affecting patients'health.Mes-enchymal stem cells are multipotent cells with multiple differen-tiation functions.The extracellular vesicles released by these cells can carry various"cargo"to corresponding cells and tis-sues,exerting biological functions.They have shown great clini-cal potential in the treatment of KOA.This study reviews the therapeutic effects and mechanisms of extracellular vesicles se-creted by mesenchymal stem cells from different tissues such as bone marrow,adipose tissue,and synovium in KOA.It is found that miRNA is an important biological component in exerting therapeutic effects.The study also discusses the research pro-gress of engineered extracellular vesicles in KOA,pointing out the current challenges in clinical application,such as standard-ized acquisition of extracellular vesicles and difficulties in targe-ted action,aiming to provide a certain reference for the basic re-search and clinical application of extracellular vesicle therapy for KOA.

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 investigate the vaccination status, characteristics and prognosis of patients suffering from a combination of COVID-19 and chronic lymphocytic anemia (CLL) in China.Methods:Clinical data of 328 patients with chronic lymphocytic leukemia (CLL) who were first diagnosed with COVID-19 and treated in the Department of Hematology of Jiangsu Provincial People’s Hospital between November 2022 and February 2023 were retrospectively analyzed. Univariate and multivariate analysis of data of patients with severe/critical COVID-19 were conducted by applying the binary logistic regression model.Results:The median age of the CLL patients was 60 (24-87) years. 23.5% (77/328) of these patients suffered from severe/critical COVID-19 infection. Univariate analysis of the data demonstrated that a combination of factors including age >67 years ( OR=2.15, 95% CI 1.24- 3.73, P=0.006), diabetes ( OR=2.09, 95% CI 1.05-4.20, P=0.037), chronic hepatitis B ( OR=2.91, 95% CI 1.30-6.51, P=0.010), CLL progressive ( OR=3.79, 95% CI 1.57-9.15, P=0.003) and CD20 antibody-based treatments within three months prior to the COVID-19 infection ( OR=2.79, 95% CI 1.35-5.77, P=0.006) were the risk factors for severe/critical COVID-19. According to the multivariate analysis, CLL progressive ( OR=2.98, 95% CI 1.10-8.10, P=0.033) was an independent risk factor for severe/critical COVID-19 and administration of the BTK (Bruton tyrosine kinase) inhibitor monotherapy might exert a protective effect and influence a positive outcome of the COVID-19 infection ( OR=0.38, 95% CI 0.16-0.90, P=0.028). Among the 242 patients who were followed up until October 2023, 9.1% (22/242) had multiple subsequent COVID-19 infections (≥3), and 2.1% (5/242) had persistent COVID-19 infections (patients with persistent positive test for the SARS-CoV-2 antigen testing until missing follow-up for any reason). The peak value of the anti-SARS-CoV-2-IgG titres was observed between three and four months post symptom onset (median: 3.511 S/CO vs 1.047 S/CO, P<0.05). The levels of immunoglobulin A gradually decreased following infection with COVID-19, and its trough levels were attained between two to four weeks post infection (median: 0.30 g/L vs 0.74 g/L, P<0.05). According to this study the mortality of patients suffering from a combination of COVID-19 infection and CLL was 2.7% (9/328), and the main reason for their death was respiratory failure and heart failure. Conclusions:A low rate of COVID-19 vaccination and a high rate of severe/critical COVID-19 infection was observed in the CLL patients. CLL progressive was associated with severe/critical COVID-19. Anti-CD20-based treatments received within the past three months might be a risk factor for exacerbation of COVID-19 infection, whereas a monotherapy with BTK inhibitors exert a protective effect and improve outcome of COVID-19 infection.

Objective To develop a low-oxygen mixed gas generator to make up for the deficiencies of low-pressure chambers and load-resistant hypoxia trainers during pilot hypoxia tolerance testing.Methods The device prepared the low-oxygen gas with the principle of gas separation,which was composed of a Sunsource OLF1100D-220AF air compressor,a SMC IDG75SAM4-03 filter,a buffer tank,an AIR Products PA3010 integrated assembly,a control box,sensors and regulators.The sensors included the pressure sensor,flow sensor,concentration sensor and dew point temperature sensor,and the control box consisted of a main control board,a power supply module,a transmission module,a communication module,a display and a housing.The embedded control software of the device was developed with KEIL 5 and C++.Results The device developed prepared the low-oxygen gas with the volume fraction being 4％to 18％and the maximum error of volume fraction being 0.05％,and the main components of the prepared gas met the technical requirements of medical oxygen as stipulated in GB 8982-2009 Oxygen supplies for medicine and aircraft breathing.Conclusion The low-oxygen gas prepared by the device has its volume fraction precisely controlled and can be used for hypoxia tolerance testing and acclimation training for pilots.[Chinese Medical Equipment Journal,2024,45(7):24-28]

Objective To investigate the efficacy and safety of ultrafiltration therapy in elderly patients with congestive heart failure(CHF)and frailty.Methods A total of 88 hospitalized elderly patients with CHF and frailty were randomly assigned to the ultrafiltration group(n=44)and the control group(n=44).The control group treated with standard drug therapy.The ultrafiltration group treated with ultrafiltration,however,diuretics were not used during ultrafiltration treatment.Efficacy assessment was compared between the two groups,including patient body weight,N-terminal pro-brain natriuretic peptide(NT-proBNP)levels at 48 hours after treatment,dyspnea severity scores at 48 hours and 1 week after treatment,hospitalization duration and readmission rate within 3 months.Safety assessment parameters included serum creatinine,urea nitrogen,Na+and K+concentration at 48 hours after treatment and creatinine level 1 week after treatment.Results Efficacy assessment indicated that at 48 hours after treatment,both groups showed a significant reduction in patient body weight and NT-proBNP levels compared to pre-treatment levels(P＜0.05).However,there were no significant difference in body weight and NT-proBNP levels before and after treatment between the two groups(P＞0.05).Dyspnea severity scores for both groups increased at 48 hours after treatment,then decreased at 1 week after treatment.The ultrafiltration group exhibited higher dyspnea severity scores than that of the control group at 48 hours after treatment(P＜0.05).The length of hospital stay and the rate of re-hospitalization within 3 months were lower in the ultrafiltration group compared to those of the control group(P＜0.05).Safety assessment revealed that there were no significant differences in serum urea nitrogen and Na+levels before and 48 hours after treatment between the two groups(P＞0.05).However,serum K+levels were higher after 48-hours treatment in the ultrafiltration group than those of the control group(P＜0.05).There were no significant changes in creatinine levels before and after treatment in the control group(P＞0.05),while creatinine levels were lower 1 week after treatment in the ultrafiltration group compared to those of pre-treatment and 48 hours after treatment,and were lower than those of the control group(P＜0.05).Conclusion Ultrafiltration is a safe and effective method for elderly patients with CHF and frailty.

BACKGROUND:At present,postoperative timing or subjective criteria by clinicians are commonly employed to determine the return-to-sport timing for patients undergoing anterior cruciate ligament reconstruction.Unfortunately,these criteria do not adequately consider the biomechanical deficits in patients following anterior cruciate ligament reconstruction. OBJECTIVE:To explore the lower extremity kinematic and kinetic characteristics of athletes after anterior cruciate ligament reconstruction during bilateral vertical jumping. METHODS:Twenty athletes undergoing anterior cruciate ligament reconstruction and twenty healthy athletes,aged 20-24 years,were recruited in Wuhan Sports University from December 2021 to December 2022.All the 40 subjects underwent a bilateral vertical jumping test.The kinematic and dynamic characteristics of the lower limbs at propulsion phase,initial landing time and peak vertical ground reaction force moment. RESULTS AND CONCLUSION:At the initial landing time,the athletes undergoing anterior cruciate ligament reconstruction showed higher hip flexion angle(P=0.031)and lower ankle plantar flexion angle(P=0.018)on the operated side compared with the healthy athletes.At the peak vertical ground reaction force moment,the athletes undergoing anterior cruciate ligament reconstruction had higher hip flexion angle(P=0.016),lower hip abduction angle(P=0.019),lower knee flexion angle(P=0.025),higher knee external rotation angle(P=0.030),and higher ankle external rotation angle(P=0.042)on the operated side compared with the healthy athletes.At the peak vertical ground reaction force moment,the athletes undergoing anterior cruciate ligament reconstruction showed lower knee extension moment(P=0.036),lower knee internal rotation moment(P=0.016),lower hip abduction moment(P=0.004),higher hip extension moment(P=0.040),and higher hip external rotation moment(P=0.005)on the operated side compared with the healthy athletes.To conclude,the athletes undergoing anterior cruciate ligament reconstruction exhibit a stiff landing pattern,in which the knee load on the operated side tends to shift to the hip joint,and show inadequate control of lower limb rotational stability.Therefore,detection and correction of abnormal biomechanical characteristics should be part of the rehabilitation after anterior cruciate ligament reconstruction.

Objective:To study correlation between related carotid ultrasound parameters and severity of coronary atherosclerosis(AS).Methods:According to number of diseased coronary arteries,a total of 116 patients with cor-onary heart disease diagnosed by coronary angiography in our hospital were divided into single vessel coronary dis-ease group(n=38,single group),double vessel coronary disease group(n=39,double group)and ≥3 vessel coro-nary disease group(n=39,multiple group).Another 41 healthy subjects were simultaneously regarded as healthy control group.General clinical data and carotid ultrasound parameters were compared among all groups,and corre-lation among them and AS severity was analyzed.Results:Compared with healthy control group,there were signifi-cant rise in levels of total cholesterol(TC),triglycerides(TG)and low density lipoprotein cholesterol(LDL-C),carotid intima-media thickness(IMT)and Crouse score in single,double and multiple groups,and significant re-ductions in plaque echo gray-scale median(GSM)in double and multiple groups.Compared with single group,there were significant rise in levels of TG and LDL-C,Gensini score and Crouse score in double and multiple groups and TC level in multiple group,and significant reduction in plaque echo GSM in multiple group.Compared with double group,there were significant rise in TC level,Gensini score and Crouse score,and significant reduction in plaque echo GSM in multiple group(P＜0.05 or＜0.01).Pearson correlation analysis indicated that Gensini score was significant positively correlated with Crouse score in these patients(r=0.580,P=0.001).Spearman correla-tion analysis indicated that IMT was significant positively correlated with number of diseased coronary arteries(r=0.582,P=0.001),and plaque echo GSM was significant inversely correlated with it(r=-0.518,P=0.001)in these patients.Conclusion:Related carotid ultrasound parameters are significantly correlated with severity of coro-nary atherosclerosis.

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.