BACKGROUND:Periprosthetic joint infection is the most common cause of early failure after total knee replacement.The current methods of preventing periprosthetic joint infection by improving the surface of the prosthesis have limitations to varying degrees.OBJECTIVE:To construct a coating material that can stably improve the surface of the implant,prevent the initial floating bacterial infection of periprosthetic infection,and regulate the bone transfer function around the implant.METHODS:(1)Material preparation:YGF polypeptide(which promotes bone formation),LL-37 polypeptide(with antibacterial properties)and YGF+LL-37 composite peptide were prepared by Fmoc solid phase peptide synthesis technology.The titanium-based materials were immersed in the three polypeptide solutions for 2 hours to obtain YGF coating,LL-37 coating and composite peptide coating coated titanium sheets.(2)In vitro experiment:Uncoated titanium sheets and coated titanium sheets were co-cultured with Escherichia coli(or Staphylococcus aureus)and the colonies were counted by plate method.MC3T3 cells were inoculated on the surface of uncoated titanium sheet and coated titanium sheet,respectively.Alizarin red staining was used to observe the calcium salt deposition on the surface of the material.Western blot assay was used to detect the protein expression of RUNX2,osteocalcin,osteopontin,and bone morphogenetic protein 2.(3)Animal experiment:24 SD rats were randomly divided into three groups:the blank group(n=8)was implanted with uncoated titanium nails in the femoral medullary canal;the control group(n=8)was implanted with uncoated titanium nails in the femoral medullary canal+intra-articular injection of Staphylococcus aureus suspension;the experimental group(n=8)was implanted with composite peptide coated titanium nails in the femoral medullary canal+intra-articular injection of Staphylococcus aureus suspension.After 5 weeks of implantation,micro-CT examination,hematoxylin-eosin staining and immunohistochemical staining of femur specimens were performed.RESULTS AND CONCLUSION:(1)In vitro experiment:Compared with uncoated titanium sheet and YGF coated titanium sheet,LL-37 coated and composite peptide coated titanium sheet could significantly inhibit the growth and reproduction of Escherichia coli and Staphylococcus aureus.Compared with uncoated titanium sheets and LL-37-coated titanium sheets,YGF-coated and composite peptide-coated titanium sheets could promote calcium salt deposition in osteoblasts and increase the protein expression of RUNX2,osteocalcin,osteopontin and bone morphogenetic protein 2.(2)Animal experiment:Micro-CT test showed that the control group had less bone mass than the blank group and the experimental group.Hematoxylin-eosin staining showed that there was a large amount of fibrous tissue around the nail channel in the control group,only a small amount of tissue fibrosis around the nail channel in the blank group,and only a small amount of tissue fibrosis around the nail channel in the experimental group.Immunohistochemical staining showed that the protein expression of interleukin 1β and tumor necrosis factor α in the control group was higher than that in the blank group and the experimental group,and the expression of osteocalcin,RUNX2 and osteopontin in the experimental group was higher than that in the blank group and the control group.(3)The results show that the titanium-based material coated with YGF+LL-37 composite peptide coating has good antibacterial ability and can promote bone transfer around the implant.

BACKGROUND:Periprosthetic joint infection is the most common cause of early failure after total knee replacement.The current methods of preventing periprosthetic joint infection by improving the surface of the prosthesis have limitations to varying degrees.OBJECTIVE:To construct a coating material that can stably improve the surface of the implant,prevent the initial floating bacterial infection of periprosthetic infection,and regulate the bone transfer function around the implant.METHODS:(1)Material preparation:YGF polypeptide(which promotes bone formation),LL-37 polypeptide(with antibacterial properties)and YGF+LL-37 composite peptide were prepared by Fmoc solid phase peptide synthesis technology.The titanium-based materials were immersed in the three polypeptide solutions for 2 hours to obtain YGF coating,LL-37 coating and composite peptide coating coated titanium sheets.(2)In vitro experiment:Uncoated titanium sheets and coated titanium sheets were co-cultured with Escherichia coli(or Staphylococcus aureus)and the colonies were counted by plate method.MC3T3 cells were inoculated on the surface of uncoated titanium sheet and coated titanium sheet,respectively.Alizarin red staining was used to observe the calcium salt deposition on the surface of the material.Western blot assay was used to detect the protein expression of RUNX2,osteocalcin,osteopontin,and bone morphogenetic protein 2.(3)Animal experiment:24 SD rats were randomly divided into three groups:the blank group(n=8)was implanted with uncoated titanium nails in the femoral medullary canal;the control group(n=8)was implanted with uncoated titanium nails in the femoral medullary canal+intra-articular injection of Staphylococcus aureus suspension;the experimental group(n=8)was implanted with composite peptide coated titanium nails in the femoral medullary canal+intra-articular injection of Staphylococcus aureus suspension.After 5 weeks of implantation,micro-CT examination,hematoxylin-eosin staining and immunohistochemical staining of femur specimens were performed.RESULTS AND CONCLUSION:(1)In vitro experiment:Compared with uncoated titanium sheet and YGF coated titanium sheet,LL-37 coated and composite peptide coated titanium sheet could significantly inhibit the growth and reproduction of Escherichia coli and Staphylococcus aureus.Compared with uncoated titanium sheets and LL-37-coated titanium sheets,YGF-coated and composite peptide-coated titanium sheets could promote calcium salt deposition in osteoblasts and increase the protein expression of RUNX2,osteocalcin,osteopontin and bone morphogenetic protein 2.(2)Animal experiment:Micro-CT test showed that the control group had less bone mass than the blank group and the experimental group.Hematoxylin-eosin staining showed that there was a large amount of fibrous tissue around the nail channel in the control group,only a small amount of tissue fibrosis around the nail channel in the blank group,and only a small amount of tissue fibrosis around the nail channel in the experimental group.Immunohistochemical staining showed that the protein expression of interleukin 1β and tumor necrosis factor α in the control group was higher than that in the blank group and the experimental group,and the expression of osteocalcin,RUNX2 and osteopontin in the experimental group was higher than that in the blank group and the control group.(3)The results show that the titanium-based material coated with YGF+LL-37 composite peptide coating has good antibacterial ability and can promote bone transfer around the implant.

Objective To investigate the mechanism of mitochondrial division regulating myocardi-al fatty acid oxidation in diabetic mice.Methods A total of 16 7-week-old male SPF C57BLKS/J diabetic mice were randomly divided into model group and mitochondrial division inhibitor 1(mdivi-1)intervention group(intervention group),with 8 mice in each group.Another 8 male SPF C57BLKS/J mice of the same age were fed adaptively for 1 week and served as control group.The changes in blood glucose and body mass were monitored in above groups.Echocardiography was conducted to detect LVEF and LVFS1 rate and E/A between early and late ventricular diastole.The pathological changes of myocardial tissue were observed by HE staining.The size,morpholo-gy and quantity of mitochondria were observed by TEM.Western blotting was used to detect the expression of mitochondrial dynamin-related protein 1(Drp1),peroxisome proliferator activated receptor α(PPARα),long chain acyl-CoA synthetase 4(ACSL4),carnitine palmitoyl transferase 1B(CPT1B),and fatty acid oxidation detection kit was conducted to determine the activity of fat-ty acid oxidation.Results Compared with the control group,the model group presented hyper-trophic cardiomyocytes and significantly larger cross-sectional diameter of cardiomyocytes(22.36±2.80 μm vs 12.71±1.78 μm,P＜0.01)than the control group.Mdivi-1 intervention resul-ted in greatly improved myocardial hypertrophy and obviously smaller cross-sectional diameter of cardiomyocytes(13.79±1.39 μm vs 22.36±2.8 μm,P＜0.01)when compared with the model group.The expression level of myocardial mitochondrial Drp1,number of mitochondria per unit area of myocardial tissue and the protein levels of PPARα,ACSL4 and CPT1B in myocardial cyto-plasm were significantly higher,and the average mitochondrial area of myocardial tissue,the ex-pression of PPARα,ACSL4 and CPT1B in myocardial mitochondria,and fatty acid oxidation activ-ity were significantly lower in the model group than the control group(P＜0.01).After mdivi-1 intervention,the expression level of myocardial mitochondrial Drp1,the number of mitochondria per unit area of myocardial tissue and the protein levels of PPARα,ACSL4 and CPT1B in myocar-dial mitochondria were notably lower,and the expression of PPARα,ACSL4 and CPT1B in myo-cardial mitochondria and fatty acid oxidation activity in myocardial tissue were significantly higher when compared with those in the model group(P＜0.05,P＜0.01).Conclusion In diabetic mice,increased myocardial mitochondrial division,decreased translocation of fatty acid oxidation regula-tory protein from cytoplasm to mitochondria,inhibited fatty acid oxidation,and myocardial injury are observed.Mdivi-1 intervention inhibits mitochondrial division,promotes fatty acid oxidation by increasing the translocation of fatty acid oxidation regulatory proteins to mitochondria,and thus improves cardiac function.

Objective To explore the value of MR diffusion tensor imaging(DTI)in evaluating the effect of march training on the thigh muscles of recruits.Methods DTI scans of the right thigh were performed three times in forty recruits:before and after the march training and one month after the rest.Fractional anisotropy(FA)was measured on the cross-sectional images of the thigh muscles,including rectus femoris(RF),vastus medialis(VM),vastus lateralis(VL),vastus intermedius(VI),gracilis muscle(GM),sartorius muscle(SM),semitendinosus muscle(STM),semimembranosus muscle(SMM),long head of biceps femoris(LHBF)and short head of biceps femoris(SHBF).The percentage changes in FA values of each muscle after the training and rest were calculated.Paired samplet-tests were used to analyze the differences in FA among the thigh muscles at different time points,and one-way ANOVA was used to analyze the differences in the percentage changes of FA among the thigh muscles after the training and rest.Results Compared to pre-training,the FA values of all thigh muscles significantly decreased after the training,with statistical differences(P＜0.05).After the rest,the FA values of all thigh muscles recovered,but statistical differences remained in RF(P＜0.001),VM(P＜0.001),VL(P=0.001),STM(P=0.046),and LHBF(P=0.013).After the training and rest,the FA values of the recruits'thigh muscles showed a"decreasing first and then increasing"trend.There were statistical differences in the percentage changes of FA after the training and the recovery percentages of FA after the rest among the thigh muscles(P＜0.001,P＜0.001).Conclusion DTI may reflect the ultra-structure changes in the thigh muscles of recruits after the march training and provide a quantitative and noninvasive assessment of muscle micro-injuries.

The histopathological growth patterns (HGPs) of colorectal cancer (CRC) liver metastasis reflect the complicated and varied interactions between tumor cells and host microenvironment. Exploring the tumor vascular and immunological features of HGPs, the relationship between HGPs and anti-tumor treatment efficacy, and HGPs prediction methods may have potential clinical aplication value for making optimal treatment strategies, evaluating patients' prognosis, and monitoring disease progression.

Objective To investigate the mechanism of mitochondrial division regulating myocardi-al fatty acid oxidation in diabetic mice.Methods A total of 16 7-week-old male SPF C57BLKS/J diabetic mice were randomly divided into model group and mitochondrial division inhibitor 1(mdivi-1)intervention group(intervention group),with 8 mice in each group.Another 8 male SPF C57BLKS/J mice of the same age were fed adaptively for 1 week and served as control group.The changes in blood glucose and body mass were monitored in above groups.Echocardiography was conducted to detect LVEF and LVFS1 rate and E/A between early and late ventricular diastole.The pathological changes of myocardial tissue were observed by HE staining.The size,morpholo-gy and quantity of mitochondria were observed by TEM.Western blotting was used to detect the expression of mitochondrial dynamin-related protein 1(Drp1),peroxisome proliferator activated receptor α(PPARα),long chain acyl-CoA synthetase 4(ACSL4),carnitine palmitoyl transferase 1B(CPT1B),and fatty acid oxidation detection kit was conducted to determine the activity of fat-ty acid oxidation.Results Compared with the control group,the model group presented hyper-trophic cardiomyocytes and significantly larger cross-sectional diameter of cardiomyocytes(22.36±2.80 μm vs 12.71±1.78 μm,P＜0.01)than the control group.Mdivi-1 intervention resul-ted in greatly improved myocardial hypertrophy and obviously smaller cross-sectional diameter of cardiomyocytes(13.79±1.39 μm vs 22.36±2.8 μm,P＜0.01)when compared with the model group.The expression level of myocardial mitochondrial Drp1,number of mitochondria per unit area of myocardial tissue and the protein levels of PPARα,ACSL4 and CPT1B in myocardial cyto-plasm were significantly higher,and the average mitochondrial area of myocardial tissue,the ex-pression of PPARα,ACSL4 and CPT1B in myocardial mitochondria,and fatty acid oxidation activ-ity were significantly lower in the model group than the control group(P＜0.01).After mdivi-1 intervention,the expression level of myocardial mitochondrial Drp1,the number of mitochondria per unit area of myocardial tissue and the protein levels of PPARα,ACSL4 and CPT1B in myocar-dial mitochondria were notably lower,and the expression of PPARα,ACSL4 and CPT1B in myo-cardial mitochondria and fatty acid oxidation activity in myocardial tissue were significantly higher when compared with those in the model group(P＜0.05,P＜0.01).Conclusion In diabetic mice,increased myocardial mitochondrial division,decreased translocation of fatty acid oxidation regula-tory protein from cytoplasm to mitochondria,inhibited fatty acid oxidation,and myocardial injury are observed.Mdivi-1 intervention inhibits mitochondrial division,promotes fatty acid oxidation by increasing the translocation of fatty acid oxidation regulatory proteins to mitochondria,and thus improves cardiac function.

Objective: To explore the relationship between isochronous substitution and BMI, waist circumference (WC), and body fat rate (FAT) among physical activity (PA), sedentary (SB), and sleep (SLP), so as to provide effective measures for obesity control in adolescents. Methods: A total of 193 adolescents aged 12-15 (90 males and 103 females) was randomly selected, and their height, weight, and BMI were measured using routine testing methods from May to August 2022. The PA, SB and SLP of the participants were measured using a 3D accelerometer (ActiGraph GT3X+). Results: The arithmetic mean value overestimated SLP (40.8%) and SB (39.6%) to some extent, and underestimated LPA (16.1%) and MVPA (3.5%) to some extent. Based on the ISM at 15 min, MVPA was substituted for other activity, BMI Z decreased by 0.17-0.22 units, WC Z decreased by 0.16-0.20 units, and FAT Z decreased by 0.17-0.22 units. The substitution between MVPA and for other activity exhibited significant asymmetry. The effects of MVPA substitutions for SB was the largest, followed by the effects of MVPA substitutions for SLP, and the effects of MVPA substitutions for LPA was the lowest. As MVPA substitutions for other behaviors, it reached its maximum (0.06-0.08 units ) when the MVPA time increased by 5 minutes. Conclusions MVPA plays an irreplaceable role in the control of adolescent obesity . While reducing SB time, MVPA duration should be increased to ensure that the daily MVPA duration is not less than 55 minutes in order to effectively control obesity.

Objective:To analyze the safety and efficacy of left atrial appendage closure(LAAC)with Watchman in patients ≥85 years with atrial fibrillation(AF).Methods:515 elderly patients with atrial fibrillation, including 73 patients aged 85 years or older(85~91), who had undergone Watchman LAAC at Zhoupu Hospital affiliated to Shanghai Health Medical College from August 2016 to December 2020, were retrospectively analyzed.Of those ≥85 years, 44(60.3%)with transesophageal echocardiography records were assigned to the elderly group.Fifty-three patients aged 60 to 65 were selected as the control group.Differences in baseline data, intraoperative conditions, antithrombotic treatment plans and 1-year follow-up prognosis were compared between the two groups.Results:Compared with the control group, there was no difference in AF types, history of ischemic stroke/transient ischaemic attack(all P>0.05), but there were higher incidences of coronary heart disease and renal insufficiency, more severe heart failure, higher CHA 2DS 2-VASC(6.0±1.5 vs.3.6±1.5), HAS-BLED(3.2±1.2 vs.2.3±1.3)scores( t values were 7.682 and 3.871, respectively, P<0.05), and a lower one-stop surgery rate(6 cases or 13.6% vs. 27 cases or 50.9%, χ2=10.517, P<0.05)in the advanced age group.There was no difference in the diameter of the Watchman device, rate of device replacement, compression percentage and residual flow between the two groups during the perioperative period.The incidences of device-related thrombosis were 4.5%(2/44)and 3.8%(2/53)for the advanced age group and the control group, respectively, but the difference was not statistically significant( P>0.05). During the 12-month follow-up, there were no cases of ischemic stroke or intracerebral hemorrhage.Three died of heart failure and 1 died of cancer. Conclusions:LAAC with Watchman is safe and effective for patients over 85 years with AF, but the decision on the procedure should be based on careful assessment of patients' cardiac and renal function and general health.

Objective:To elucidate the clinical characteristics of bloodstream infection in patients with allogeneic hematopoietic stem cell transplantation (allo-HSCT) in our hospital and improves the survival of transplant patients with bloodstream infection.Methods:Two hundred and ten patients with allo-HSCT from the Department of Hematology were retrospectively analyzed between October 2014 and September 2019. Pathogen distribution, drug resistance, risk factors, and outcomes were investigated in 49 allo-HSCT patients with bloodstream infections.Results:Forty-nine of 210 patients with allo-HSCT had bloodstream infection, and 59 pathogenic microorganisms were identified, mainly Gram-negative bacteria (67.8%) , of which E. coli had the highest incidence (23.7%) , CRO accounted for 42.5%, and Grampositive bacteria accounted for 23.7% (without vancomycin or linezolid-resistant strain) . Additionally, fungi accounted for 8.5%. Univariate analysis suggested that the risk factors of bloodstream infection were gender, pretransplant disease status, and conditioning regimen. In contrast, multivariate analysis showed that bloodstream infection was mainly related to conditioning regimens. Further grouping results showed that 77.6% of patients with neutropenia had bloodstream infections, and 22.4% of patients with non-neutropenia had bloodstream infections; 81.0% of patients with active infections before transplantation had bloodstream infections, while bloodstream infection occurred in 16.9% of patients without active infection. Survival analysis showed that long-term survival of patients with bloodstream infection is shorter than that of patients without bloodstream infection and long-term survival of patients with CRO infection is shorter than that of patients without CRO infection. The survival of patients with neutropenia longer than 14 d is shorter than that of patients with neutropenia shorter than 14 d. Furthermore, there is no correlation between whether there is an active infection before transplantation and whether they are in a neutropenic state at the time of infection and survival.Conclusion:Our results suggest that effective prevention of bloodstream infections from drug-resistant bacteria, particularly CRO, shortening the duration of neutropenia, eradication of potential infections before transplantation, and patient-adaptive conditioning could reduce transplant-related mortality and improve prognosis.

Objective:To investigate the first aid management, doctors′ command of first aid knowledge of private dental clinics in Zhangjiakou city and the influencing factors, for references in strengthening the emergency management level of these clinics and the emergency capacity of doctors.Methods:Customized questionnaire was used in a survey of 192 doctors in 64 private dental clinics in the city from June to September in 2019, and 172 valid responses were recovered. The questionnaire covered such aspects as basics of these doctors, first-aid training received and first-aid knowledge command, as well as first-aid management of these clinics. Enumeration data were indicated with frequency number and percentage, while measurement data were indicated with ± s. Univariate analysis of first-aid knowledge scoring was made with Mann-Whitney U test. Results:The first-aid knowledge of dental doctors in private dental clinics in Zhangjiakou was poor, scoring 51.8±14.6 points in general, and those scoring above 60 points accounted for merely 19.3%. The proportion of dental doctors participating in first-aid knowledge training and emergency drill was low. Only 7.8% of the private dental clinics in Zhangjiakou had complete rescue equipment. Scoring of the dental doctors participating in emergency drill and emergency knowledge training was higher than those without such experiences, with the difference being statistically significant( P<0.001). Conclusions:Private dental clinics should regularly arrange their staff to participate in first-aid training and emergency drills; prepare an emergency plan, equip rescue facilities and first-aid medication; dental doctors should strengthen their study of first-aid knowledge.