ObjectiveThe aim of this study was to investigate the prophylactic effects of caloric restriction (CR) on lipopolysaccharide (LPS)-induced septic cardiomyopathy (SCM) and to elucidate the mechanisms underlying the cardioprotective actions of CR. This research aims to provide innovative strategies and theoretical support for the prevention of SCM. MethodsA total of forty-eight 8-week-old male C57BL/6 mice, weighing between 20-25 g, were randomly assigned to 4 distinct groups, each consisting of 12 mice. The groups were designated as follows: CON (control), LPS, CR, and CR+LPS. Prior to the initiation of the CR protocol, the CR and CR+LPS groups underwent a 2-week acclimatization period during which individual food consumption was measured. The initial week of CR intervention was set at 80% of the baseline intake, followed by a reduction to 60% for the subsequent 5 weeks. After 6-week CR intervention, all 4 groups received an intraperitoneal injection of either normal saline or LPS (10 mg/kg). Twelve hours post-injection, heart function was assessed, and subsequently, heart and blood samples were collected. Serum inflammatory markers were quantified using enzyme-linked immunosorbent assay (ELISA). The serum myocardial enzyme spectrum was analyzed using an automated biochemical instrument. Myocardial tissue sections underwent hematoxylin and eosin (HE) staining and immunofluorescence (IF) staining. Western blot analysis was used to detect the expression of protein in myocardial tissue, including inflammatory markers (TNF-α, IL-9, IL-18), oxidative stress markers (iNOS, SOD2), pro-apoptotic markers (Bax/Bcl-2 ratio, CASP3), and SIRT3/SIRT6. ResultsTwelve hours after LPS injection, there was a significant decrease in ejection fraction (EF) and fractional shortening (FS) ratios, along with a notable increase in left ventricular end-systolic diameter (LVESD). Morphological and serum indicators (AST, LDH, CK, and CK-MB) indicated that LPS injection could induce myocardial structural disorders and myocardial injury. Furthermore, 6-week CR effectively prevented the myocardial injury. LPS injection also significantly increased the circulating inflammatory levels (IL-1β, TNF-α) in mice. IF and Western blot analyses revealed that LPS injection significantly up-regulating the expression of inflammatory-related proteins (TNF-α, IL-9, IL-18), oxidative stress-related proteins (iNOS, SOD2) and apoptotic proteins (Bax/Bcl-2 ratio, CASP3) in myocardial tissue. 6-week CR intervention significantly reduced circulating inflammatory levels and downregulated the expression of inflammatory, oxidative stress-related proteins and pro-apoptotic level in myocardial tissue. Additionally, LPS injection significantly downregulated the expression of SIRT3 and SIRT6 proteins in myocardial tissue, and CR intervention could restore the expression of SIRT3 proteins. ConclusionA 6-week CR could prevent LPS-induced septic cardiomyopathy, including cardiac function decline, myocardial structural damage, inflammation, oxidative stress, and apoptosis. The mechanism may be associated with the regulation of SIRT3 expression in myocardial tissue.

ObjectiveFat infiltration has been shown to be closely related to muscle mass loss and a variety of muscle diseases. This study proposes a method based on phase-angle electrical impedance tomography (ΦEIT) to visualize the electrical characteristic response caused by muscle fat infiltration, aiming to provide a new technical means for early non-invasive detection of muscle mass deterioration. MethodsThis study was divided into two parts. First, a laboratory pork model was constructed to simulate different degrees of fat infiltration by injecting1 ml or 2 ml of emulsified fat solution into different muscle compartments, and the phase angle images were reconstructed using ΦEIT. Second, a human experiment was conducted to recruit healthy subjects (n=8) from two age groups (20-25 years old and 26-30 years old). The fat content percentage η_fat of the left and right legs was measured by bioelectrical impedance analysis (BIA), and the phase angle images of the left and right calves were reconstructed using ΦEIT. The relationship between the global average phase angle Φ_M and the spatial average phase angle Φ_Mi of each muscle compartment and fat infiltration was further analyzed. ResultsIn the laboratory pork model, the grayscale value of the image increased with the increase of η_fat and Φ_M showed a downward trend. The results of human experiments showed that at the same fat content percentage, the Φ_M of the 26-30-year-old group was about 20%-35% lower than that of the 20-25-year-old group. The fat content percentage was significantly negatively correlated with Φ_M. In addition, the M₂ (soleus) compartment was most sensitive to fat infiltration, and the spatial average phase angles of the M₂ (soleus), M₃ (tibialis posterior and flexor digitorum longus), and M₄ (tibialis anterior, extensor digitorum longus, and peroneus longus) compartments all showed significant inter-group differences. ConclusionΦEIT imaging can effectively distinguish different degrees of fat infiltration, especially in deep, small or specially located muscles, showing high sensitivity, demonstrating the potential application of this method in local muscle mass monitoring and early non-invasive diagnosis.

Objective To design an experimental device for simulating the interface micro motion of bone trabecular prosthesis and carry out the finite element analysis.Methods The experimental device was composed of a screw-in cylinder with threads,a flexible hinge,a micro-motion rod,a trabecular prosthesis,a connecting rod and a fixation post.A model of the experimental device was constructed with SolidWorks software,and then imported into ABAQUS software to establish a finite element model.An axial displacement load was applied to the femur to analyze the effects of the position of the flexible hinge,the gap between the prosthesis and the femur and the length of the connecting rod on the micro motion.Results The interface micro motion produced by the experimental device increased with the distance of the flexible hinge from the lower end of the screwed-in cylinder;the gap between the prosthesis and the femur did not affect the interface micro motion when the gap was not lower than 20 μm;the interface micro motion rose with the length of the connecting rod.Conclusion The experimental device can accurately simulate the micro motion of different bone trabecular prosthesis interfaces,and can be used for studying the effect of the interface micro motion on osseointegration.[Chinese Medical Equipment Journal,2024,45(1):25-30]

Objective To analyze the antigen recognition sites of commercial and homemade antibodies against aquaporin(AQP)9,and to identify the application effect.Methods Western blotting was used to compare the efficacy of three commercial antibodies and self-made antibody in identifying AQP9 genotypes.The antigen recognition sites of four antibodies and their specificities in practical applications were analyzed.Results Western blotting showed that protein bands of three commercial antibodies were detected in both WT and Aqp9-/-mice.The keyhole limpet hemocyanin(KLH)conjugated synthetic peptides corresponding to the three commercial antibodies were derived from rat,human and human,respectively.And The sequences of these three synthetic peptides were different from those of mice.AQP3/7 and AQP9 have similar molecular weight and were expressed in the liver with high homology.An obvious band of self-made antibody was observed at the 27 kD position in WT mice,but no band was observed at the corresponding position in Aqp9-/-mice.Conclusion Commercial antibodies 1 and 3 can be used to assist in the identification of genotypes in Aqp9-/-mice.Homemade antibodies can accurately identify genotypes at the protein level.

Objective To establish a rapid and convenient UPLC-MS/MS method for the determination of tamoxifen and its active metabolite endoxifen in plasma of patients with breast cancer.Methods With diazepam as the internal standard,the plasma sample was precipitated with acetonitrile and methanol-acetonitrile was used as mobile phase.The samples were separated by chromatographic column ZORBAX Eclipse plus C18(18 μm,2.1 mm x50 mm)and scanned by electrospray ion source and positive ion multiple reaction monitoring mode.The ion channels were detected as tamoxifen m/z 372.0→72.1,endoxifen m/z 374.0→58.2 and diazepam m/z 285→192.9.Results The linearity of tamoxifen and endoxifen were good in the concentration range of 1-500 ng·mL-1(R2=0.999 5)and 0.5-250 ng·mL-1,respectively(R2=0.999 9).The intra-day and inter-day precision of low,medium and high quality control concentrations were all less than 10％.Tamoxifen and endoxifen were stable at low temperature and stable after repeated freeze-thaw.Conclusion The experimental results show that the method meets the requirements of biological sample analysis,and the sample treatment is simple,specific,and can be used for the accurate and rapid determination of tamoxifen and indoloxifen in human plasma.

Objective To explore the role of exosomes secreted by induced pluripotent stem cells(iPSC)in promoting the proliferation,invasion and migration of keratinocytes,thereby facilitating wound healing.Methods Extract iPSC-Exos and identify them through transmission electron microscopy,nanoparticle tracking analysis technology,and Western blotting.Purified iPSC-Exos labeled with PKH26 were added to keratinocytes(HaCaT)for the determination of keratinocyte uptake of exosomes.The optimal working concentration of exosomes was assessed using cell counting kit-8(CCK-8),and cells were divided into control group(cell scratch),and experimental group(cell scratch followed by addition of exosomes at the optimal working concentration).Proliferation,migration,and invasion abilities of cells in each group were evaluated using CCK-8,5-ethynyl-2'-deoxyuridine(EdU),scratch assay,and Transwell assay.Results iPSC-Exos exhibit a membranous vesicular structure with a round or elliptical shape,and their diameter is(120.00±25.00)nm.The expression of characteristic surface markers CD9,CD63,and CD81 on iPSC-Exos is positive in the experimental group,while being negative in the control group.HaCaT cells are capable of internalizing iPSC-Exos.After 24 hours of intervention,the scratch healing rates in the control and experimental groups are(25.70±1.07)％and(71.60±12.76)％,respectively.The Transwell invasion cell numbers are(86.33±10.79)and(166.33±24.13)in the control and experimental groups,and the EdU-positive proportions are(45.30±3.17)％and(78.10±6.29)％,respectively.The above indicators in the experimental group show statistically significant differences compared to the control group(all P＜0.05).Conclusion The exosomes secreted by pluripotent stem cells can promote the proliferation,migration,and invasion of keratinocytes,thereby indirectly promoting wound healing.

Objective To investigate the implementation of surveillance,prevention and control measures for healthcare-associated infection(HAI)in maternal and child healthcare(MCH)institutions,and provide policy evi-dence for optimizing HAI prevention and control in MCH institutions.Methods Stratified sampling was conducted among the MCH institutions at provincial,municipal and county levels in 8 provinces/autonomous regions.A uni-fied questionnaire was designed and the online survey was conducted through"Questionnaire Star".Results The data from 123 MCH institutions were included in the analysis.90.24％of the MCH institutions carried out compre-hensive surveillance on HAI.The ratios of MCH institutions which implemented targeted surveillance on HAI in neonatal intensive care unit(NICU),surgical site infection,multidrug-resistant organisms(MDROs)and HAI in intensive care units(non-NICU excluded)were 89.66％,85.96％,80.77％,and 74.19％,respectively.51.22％MCH institutions adopted information surveillance system on HAI cases.94.31％MCH institutions carried out surveillance on hand hygiene compliance.Over 90％MCH institutions carried out surveillance on environment hy-giene in high-risk departments.71.54％MCH institutions conducted centralized cleaning,disinfection,sterilization and supply for reusable medical instruments in the central sterile supply department(CSSD).Over 90％MCH insti-tutions established three-level pre-examination triage systems.86.18％set up transitional wards.MCH institutions generally adopted a management model with established effective communication,full appointment visits,and sepa-rate visits for special medical groups,such as registered pregnant women,high-risk newborns,healthcare groups,and long-term rehabilitation patients.However,the ratio of institutions conducting on-line follow-up visits was less than 50％.Conclusion MCH institutions have generally carried out comprehensive and targeted surveillance on HAI.Information surveillance need to be facilitated.Hand hygiene and environmental hygiene surveillance has been popularized to a certain extent at all levels of MCH institutions.The cleaning,disinfection,sterilization,and supply processes of reusable medical devices in a few MCH institutions are not standardized.Special medical populations get effective management.On-line healthcare is to be further promoted.

Brasilicardin A, a diterpene glycoside isolated from pathogenic actinomycete Nocardia brasiliensis IFM 0406, has become a novel immunosuppressant candidate due to its significant immunosuppressive activity, low toxicity and unique mechanism of action. However, brasilicardin A and its analogues have become a research hotspot to the development of this promising immunosuppressant because of the low-yield production in the natural pathogenic producer and the synthetically challenging skeleton. According to the reported biosynthetic pathway of brasilicardin A, the function of involved diterpene synthase was analyzed by bioinformatics. Then the genes bra1-5 that synthesize the brasilicardin A skeleton were directionally amplified from the pathogenic strain N. brasiliensis IFM 0406, and heterologous expression was achieved successfully in Streptomyces albus R1. The compounds were isolated and purified by using various column chromatographies including silica gel column chromatography and semi-preparative HPLC. Six new brasilicardins were established and named brasilicardin H-M. The activity of brasilicardins was screened using lipopolysaccharide (LPS)-activated mouse primary macrophage inflammation model. Brasilicardin H-M exhibited good inhibitory activity on nitric oxide (NO) release with IC₅₀ values of 28.24 ± 3.70, 37.44 ± 2.00, 39.85 ± 4.02, 26.77 ± 4.40, 65.25 ± 1.48 and 15.24 ± 2.72 μmol·L^-1, respectively (indomethacin as the positive control with IC₅₀ value of 34.28 ± 4.10 μmol·L^-1). The results indicated that six compounds had potential anti-inflammatory activity. This study laid a foundation for the elucidation of the brasilicardin A biosynthetic pathway and evaluation of the structure-activity relationship as well as new drug developments.

Infections caused by drug-resistant bacteria attaching to medical devices pose significant challenges to public health,and as such development of anti-adhesion and bactericidal surfaces with long-term performance is of practical importance.In this study,polydopamine(PDA),silver nanoparticles(AgNPs)and PDA were sequentially deposited on the glass substrate,and then polysulfobetaine methacrylate(PSBMA),a zwitterionic polymer,with a loop conformation was grafted onto the PDA surface to construct PAP-PSBMA-loop,a dual-functional antibacterial coating combining bacterial adhesion-resistance and photothermal sterilization properties.Due to the robust antifouling ability of the zwitterionic polymer and the excellent photothermal conversion ability of PDA and AgNPs,PAP-PSBMA-loop coating demonstrated excellent resistance to bacterial adhesion and sterilization performance under near-infrared(NIR)irradiation.After 7 days of incubation with bacteria,the coating surface exhibited a low bacterial coverage of 1.7%,and was able to suppress biofilm formation effectively and kill>99%of the bacteria that managed to adhere upon exposure to NIR irradiation.

Objective To explore the clinical efficacy and safety of early surgical treatment for spinal thoracolumbar fracture without nerve injury.Methods The clinical data of 80 patients with spinal thoracolumbar fracture without nerve injury who were admitted to the department of spinal surgery in our hospital were retrospectively analyzed.According to the different operation timing,those who underwent surgery within 72 hours after fracture were included in the early operation group(n=41),and those who underwent surgery 72 hours to 2 weeks after fracture were included in the elective operation group(n=39).All operations were performed through the Wiltse approach for short-segment pedicle screw fixation on the injured vertebra.The operation time,intraoperative blood loss,hospital stay and incidence of complication of the two groups were compared.The visual analogue scale(VAS)scores,Oswestry disability index(ODI),compression rate of the anterior edge height of the injured vertebra,and the Cobb angle in the sagittal position of the injured vertebra before surgery,1 week after surgery and 1 year after surgery were compared between the two groups.The improvement rates of the anterior edge height compression and the Cobb angle in the sagittal position of the injured vertebra 1 week and 1 year after surgery were compared between the two groups.Results There was no significant difference in the operation time,intraoperative blood loss or total incidence of complications between the two groups(P>0.05).The hospital stay in the early operation group was shorter than that in the elective operation group,and the difference was statistically significant(P<0.05).The VAS scores and ODI 1 week and 1 year after surgery of the two groups were better than those before surgery,and the differences were statistically significant(P<0.05).There was no significant difference in the VAS scores or ODI at each time point before and after surgery between the two groups(P>0.05).The compression rate of the anterior edge height and Cobb angle in the sagittal position of the injured vertebra 1 week and 1 year after surgery in the two groups were lower/smaller than those before surgery,with statistically significant differences(P<0.05).There was no statistically significant difference in the compression rate of the anterior edge height or Cobb angle before surgery in the sagittal position of the injured vertebrae between the two groups(P>0.05).The compression rate of the anterior edge height and Cobb angle in the sagittal position of the injured vertebra 1 week and 1 year after surgery in the early operation group were lower/smaller than those in the elective operation group,and the differences were statistically significant(P<0.05).The improvement rates of the anterior edge height compression and the Cobb angle in the sagittal position of the injured vertebra 1 week and 1 year after surgery in the early operation group were better than those in the elective operation group,and the differences were statistically significant(P<0.05).Conclusion Early surgical treatment for spinal thoracolumbar fracture without nerve damage is safe,it can significantly shorten hospitalization time,obtain good fracture reduction quality and definite therapeutic effects.However,a comprehensive preoperative evaluation of the patients' condition is necessary to ensure surgical safety.