BACKGROUND:Plate fixation is the mainstream method for the surgical treatment of distal femoral fractures.The intramedullary nailing has the advantages of minimally invasive,such as less soft tissue injury and bone blood supply destruction.At the same time,it is a central fixation and has better biomechanical effect.Therefore,retrograde intramedullary nailing has become another option for the internal fixation of distal femoral fractures.OBJECTIVE:The biomechanical characteristics of new retrograde intramedullary nail on lateral femur condyle,common femoral retrograde intramedullary nail,and lateral femur condyle anatomical locking plate for the treatment of A2-type distal femoral fractures were compared using finite element analysis,and the advantages of new retrograde intramedullary nail on lateral femur condyle was studied.METHODS:A new retrograde intramedullary nail on lateral femur condyle was designed,which was inserted into the bone cortex in front of the insertion point of the lateral collateral ligament of the lateral femoral condyle.A CT scan was performed on the lower limb bone of a male volunteer,and a three-dimensional model of the femur was established.The model was then segmented to create a three-dimensional model of a femoral distal A2-type fracture,The three-dimensional models of small(small group),standard type retrograde intramedullary nail on the lateral femoral condyle(standard group),common retrograde intramedullary needle(common group),and lateral femur condyle anatomical locking plate(plate group)were established respectively.The axial stresses of 600,1 800 N and the torsional load of 4 000,8 000 N·mm were applied to the models,and the displacement and stress of femur and the displacement,stress and shear force of internal fixators were observed in each group.RESULTS AND CONCLUSION:(1)When subjected to axial load of 600 and 1 800 N,the femoral peak displacement,the femoral peak stress,and the peak stress of interal fixation in the standard group were the lowest among the four groups.(2)When subjected to torsional load of 4 000 and 8 000 N·mm,the femoral peak displacement and peak displacement of the internal fixation in the standard group were the lowest among the four groups.(3)Compared with femoral lateral condylar locking plate and common retrograde intramedullary needle,the new retrograde intramedullary needle on lateral femur condyle has mechanical advantages of reducing stress concentration and decreasing the risk of internal fixation failure.

BACKGROUND:In vitro construction of tissue-engineered intestinal models plays an important role in intestinal regeneration and intestinal disease research.The interaction of intestinal nervous system and intestinal epithelial barrier to maintain body homeostasis is a hot topic in the bionic construction of tissue-engineered intestinal tract.OBJECTIVE:To construct a bionic model that can mimic the enteric nervous system in vivo.METHODS:Using fibroin protein with villus structure as scaffold,human induced neural stem cells solidified with collagen were added to intestinal epithelial cells(Caco-2 and HT29-MTX-E12)for 3-day culture to construct a co-culture system of intestinal epithelial cells and nerve cells(co-culture group).Human induced neural stem cells or intestinal epithelial cells cultured alone that were inoculated with fibroin scaffolds were set as controls.Cell morphology was observed by scanning electron microscopy and hematoxylin-eosin staining.Cell activity was detected by Live/Dead cell staining.Human induced neural stem cell differentiation was detected by β-microtubulin immunofluorescence staining.Intestinal epithelial histological properties and barrier function were detected by microvillin,sucrase-isomaltase,tight junction protein 1,E-calmodulin,and mucin-2 immunofluorescence staining.The function of mucus secretion from intestinal epithelial cells was detected by Alcian blue staining.Alkaline phosphatase staining was performed to detect differentiation of intestinal epithelial cells,at the same time,sucrase-isomaltase,tight junction protein 1,and alkaline phosphatase mRNAs were detected by RT-qRCR.RESULTS AND CONCLUSION:The neuralized intestinal mucosal co-culture model with villi structure was successfully constructed,and neural stem cells and intestinal epithelial cells on the fibroin scaffold showed good cellular activities.After neuralization,the activity of alkaline phosphatase and sucrase-isomaltase in intestinal epithelial cells was enhanced,while the expression level of tight junction protein 1 was up-regulated.To conclude,the neuralized bionic intestinal epithelial model is beneficial to the maturation of intestinal mucosal epithelial cells and the formation of barrier function.

BACKGROUND:Plate fixation is the mainstream method for the surgical treatment of distal femoral fractures.The intramedullary nailing has the advantages of minimally invasive,such as less soft tissue injury and bone blood supply destruction.At the same time,it is a central fixation and has better biomechanical effect.Therefore,retrograde intramedullary nailing has become another option for the internal fixation of distal femoral fractures.OBJECTIVE:The biomechanical characteristics of new retrograde intramedullary nail on lateral femur condyle,common femoral retrograde intramedullary nail,and lateral femur condyle anatomical locking plate for the treatment of A2-type distal femoral fractures were compared using finite element analysis,and the advantages of new retrograde intramedullary nail on lateral femur condyle was studied.METHODS:A new retrograde intramedullary nail on lateral femur condyle was designed,which was inserted into the bone cortex in front of the insertion point of the lateral collateral ligament of the lateral femoral condyle.A CT scan was performed on the lower limb bone of a male volunteer,and a three-dimensional model of the femur was established.The model was then segmented to create a three-dimensional model of a femoral distal A2-type fracture,The three-dimensional models of small(small group),standard type retrograde intramedullary nail on the lateral femoral condyle(standard group),common retrograde intramedullary needle(common group),and lateral femur condyle anatomical locking plate(plate group)were established respectively.The axial stresses of 600,1 800 N and the torsional load of 4 000,8 000 N·mm were applied to the models,and the displacement and stress of femur and the displacement,stress and shear force of internal fixators were observed in each group.RESULTS AND CONCLUSION:(1)When subjected to axial load of 600 and 1 800 N,the femoral peak displacement,the femoral peak stress,and the peak stress of interal fixation in the standard group were the lowest among the four groups.(2)When subjected to torsional load of 4 000 and 8 000 N·mm,the femoral peak displacement and peak displacement of the internal fixation in the standard group were the lowest among the four groups.(3)Compared with femoral lateral condylar locking plate and common retrograde intramedullary needle,the new retrograde intramedullary needle on lateral femur condyle has mechanical advantages of reducing stress concentration and decreasing the risk of internal fixation failure.

BACKGROUND:In vitro construction of tissue-engineered intestinal models plays an important role in intestinal regeneration and intestinal disease research.The interaction of intestinal nervous system and intestinal epithelial barrier to maintain body homeostasis is a hot topic in the bionic construction of tissue-engineered intestinal tract.OBJECTIVE:To construct a bionic model that can mimic the enteric nervous system in vivo.METHODS:Using fibroin protein with villus structure as scaffold,human induced neural stem cells solidified with collagen were added to intestinal epithelial cells(Caco-2 and HT29-MTX-E12)for 3-day culture to construct a co-culture system of intestinal epithelial cells and nerve cells(co-culture group).Human induced neural stem cells or intestinal epithelial cells cultured alone that were inoculated with fibroin scaffolds were set as controls.Cell morphology was observed by scanning electron microscopy and hematoxylin-eosin staining.Cell activity was detected by Live/Dead cell staining.Human induced neural stem cell differentiation was detected by β-microtubulin immunofluorescence staining.Intestinal epithelial histological properties and barrier function were detected by microvillin,sucrase-isomaltase,tight junction protein 1,E-calmodulin,and mucin-2 immunofluorescence staining.The function of mucus secretion from intestinal epithelial cells was detected by Alcian blue staining.Alkaline phosphatase staining was performed to detect differentiation of intestinal epithelial cells,at the same time,sucrase-isomaltase,tight junction protein 1,and alkaline phosphatase mRNAs were detected by RT-qRCR.RESULTS AND CONCLUSION:The neuralized intestinal mucosal co-culture model with villi structure was successfully constructed,and neural stem cells and intestinal epithelial cells on the fibroin scaffold showed good cellular activities.After neuralization,the activity of alkaline phosphatase and sucrase-isomaltase in intestinal epithelial cells was enhanced,while the expression level of tight junction protein 1 was up-regulated.To conclude,the neuralized bionic intestinal epithelial model is beneficial to the maturation of intestinal mucosal epithelial cells and the formation of barrier function.

Objective: This study aimed to construct an animal model of heart failure with preserved ejection fraction (HFpEF) that integrates disease and syndrome based on the "deficiency-blood stasis-toxin" pathogenesis and to evaluate it comprehensively. Methods: The HFpEF mouse model was constructed using a combination of Nω-nitro-L-arginine methyl ester (L-NAME) and a high-fat diet. According to the random number table method, SPF-grade male C57BL/6J mice were randomly assigned to the control, L-NAME, high-fat diet, and model groups, 10 in each group. Comprehensive observations and data collection on macroscopic signs (e.g., fur condition, mental state, stool and urine, oral and nasal condition, paw and body condition, etc.) and cardiac function were performed after 10 and 16 weeks of model induction. Additionally, the syndrome evolution was elucidated based on diagnostic criteria for clinical syndromes of heart failure. Furthermore, pathological and molecular biological examinations of myocardial tissue were performed to assess the stability and reliability of the model. Results: Mice in the model group showed typical characteristics of syndrome of qi deficiency and blood stasis, as well as syndrome of internal heat accumulation, including lethargy, slow response, dull paw color and oral/nasal color, exercise intolerance, abnormal platelet activation, dry feces, and dark yellow urine. The time window for these syndromes was between 10 and 16 weeks post-modeling. Cardiac function assessments revealed severe diastolic dysfunction, concentric myocardial hypertrophy, and myocardial fibrosis in the model group. Pathological examinations showed a significantly increased collagen deposition in the myocardial interstitium, enlarged cross-sectional area of cardiomyocytes, and sparse coronary microvasculature in the model group. Molecular biological analyses indicated marked activation of the inducible nitric oxide synthase/nuclear factor kappa-light-chain-enhancer of activated B cells/NOD-like receptor family pyrin domain containing 3 inflammatory pathway and significantly elevated inflammation levels in the myocardial tissue of the model group. Although mice in the L-NAME and high-fat diet groups also showed certain manifestations of qi deficiency syndrome, the substantial cardiac damage was relatively limited compared to the control group. Conclusion This study has constructed an animal model of HFpEF that integrates disease and syndrome based on the "deficiency-blood stasis-toxin" pathogenesis. The macroscopic and microscopic characteristics of this model are consistent with the manifestations of syndrome of qi deficiency and blood stasis, toxin syndrome, and syndrome of internal heat accumulation. Moreover, it can stably simulate the HFpEF state and reflect phenotypic changes in human disease. This model provides a suitable experimental platform to explore the pathogenesis of HFpEF, evaluate the effectiveness of traditional Chinese medicine (TCM) treatment regimens, and promote in-depth research on TCM syndromes of heart failure.

OBJECTIVE To explore the efficacy and safety of sofosbuvir-velpatasvir(SOF/VEL)combined with or without ribavirin(RBV)in treatment of the patients with genotype 3(GT3)chronic hepatitis C(CHC)and liver cirrhosis.METHODS Totally 230 patients with CT3 CHC and liver cirrhosis who were treated in Traditional Chi-nese Hospital of Xinjiang Uygur Autonomous Region,Xinjiang Hetian Specialized Hospital of Infectious Diseases and Xinjiang Manasi County People's Hospital from Jun.2018 to Mar.2023 were recruited as the research sub-jects.The clinical curative effects were observed after the subjects were treated with single SOF-VEL or the com-bination with RBV for 12 to 24 weeks.The indexes including high-sensitivity hepatitis C RNA(HCV RNA),blood routine indexes,liver function indexes and noninvasive diagnosis indexes for liver fibrosis were observed,and the sustained virological response 12 weeks after the treatment(SVR12)was analyzed.RESULTS The mean age of the enrolled patients was(42.31±11.18)years old,the male patients accounted for 66.52％,and there were 137 cases of GT3a and 93 cases of GT3b 93,there were 183 cases of CHC,44 cases of compensated cirrhosis(CC)and 3 cases of decompensated cirrhosis(DCC).There were 189 cases of single HCV infection,33 cases of mixed infections of HCV and HIV,6 cases of mixed infections of HBV/HCV and 2 cases of triple infections of HBV/HCV/HIV.The overall SVR12 of the 230 patients was 99.57％,the SVR12 of the GT3a type patients was 100.00％,the GT3b type patients 98.92％.The SVR12 of the patients with CHC,CC and DCC were 99.45％,100.00％and 100.00％,respectively.The SVR12 of the patients with single HCV infection,HCV/HIV infec-tion,HBV/HCV infection and HBV/HCV/HIV were 99.47％,100.00％,100.00％and 100.00％,respective-ly.No patient quit the direct-acting antivirals(DAAs)treatment due to the drug-induced adverse reactions.1 pa-tient had relapse due to irregular administration of DAAs.CONCLUSION The virological response rate is high a-mong the patients with GT3 CHC and liver cirrhosis who are treated with single SOF/VEL or the combination with RBV,with the safety favorable.

Objective To investigate the distribution and antimicrobial resistance profiles of common pathogens isolated from cerebrospinal fluid(CSF)in CHINET program from 2015 to 2021.Methods The bacterial strains isolated from CSF were identified in accordance with clinical microbiology practice standards.Antimicrobial susceptibility test was conducted using Kirby-Bauer method and automated systems per the unified CHINET protocol.Results A total of 14 014 bacterial strains were isolated from CSF samples from 2015 to 2021,including the strains isolated from inpatients(95.3％)and from outpatient and emergency care patients(4.7％).Overall,19.6％of the isolates were from children and 80.4％were from adults.Gram-positive and Gram-negative bacteria accounted for 68.0％and 32.0％,respectively.Coagulase negative Staphylococcus accounted for 73.0％of the total Gram-positive bacterial isolates.The prevalence of MRSA was 38.2％in children and 45.6％in adults.The prevalence of MRCNS was 67.6％in adults and 69.5％in children.A small number of vancomycin-resistant Enterococcus faecium(2.2％)and linezolid-resistant Enterococcus faecalis(3.1％)were isolated from adult patients.The resistance rates of Escherichia coli and Klebsiella pneumoniae to ceftriaxone were 52.2％and 76.4％in children,70.5％and 63.5％in adults.The prevalence of carbapenem-resistant E.coli and K.pneumoniae(CRKP)was 1.3％and 47.7％in children,6.4％and 47.9％in adults.The prevalence of carbapenem-resistant Acinetobacter baumannii(CRAB)and Pseudomonas aeruginosa(CRPA)was 74.0％and 37.1％in children,81.7％and 39.9％in adults.Conclusions The data derived from antimicrobial resistance surveillance are crucial for clinicians to make evidence-based decisions regarding antibiotic therapy.Attention should be paid to the Gram-negative bacteria,especially CRKP and CRAB in central nervous system(CNS)infections.Ongoing antimicrobial resistance surveillance is helpful for optimizing antibiotic use in CNS infections.

Objective To investigate the antimicrobial resistance of clinical isolates from elderly patients(≥65 years)in major medical institutions across China.Methods Bacterial strains were isolated from elderly patients in 52 hospitals participating in the CHINET Antimicrobial Resistance Surveillance Program during the period from 2015 to 2021.Antimicrobial susceptibility test was carried out by disk diffusion method and automated systems according to the same CHINET protocol.The data were interpreted in accordance with the breakpoints recommended by the Clinical and Laboratory Standards Institute(CLSI)in 2021.Results A total of 514 715 nonduplicate clinical isolates were collected from elderly patients in 52 hospitals from January 1,2015 to December 31,2021.The number of isolates accounted for 34.3％of the total number of clinical isolates from all patients.Overall,21.8％of the 514 715 strains were gram-positive bacteria,and 78.2％were gram-negative bacteria.Majority(90.9％)of the strains were isolated from inpatients.About 42.9％of the strains were isolated from respiratory specimens,and 22.9％were isolated from urine.More than half(60.7％)of the strains were isolated from male patients,and 39.3％isolated from females.About 51.1％of the strains were isolated from patients aged 65-＜75 years.The prevalence of methicillin-resistant strains(MRSA)was 38.8％in 32 190 strains of Staphylococcus aureus.No vancomycin-or linezolid-resistant strains were found.The resistance rate of E.faecalis to most antibiotics was significantly lower than that of Enterococcus faecium,but a few vancomycin-resistant strains(0.2％,1.5％)and linezolid-resistant strains(3.4％,0.3％)were found in E.faecalis and E.faecium.The prevalence of penicillin-susceptible S.pneumoniae(PSSP),penicillin-intermediate S.pneumoniae(PISP),and penicillin-resistant S.pneumoniae(PRSP)was 94.3％,4.0％,and 1.7％in nonmeningitis S.pneumoniae isolates.The resistance rates of Klebsiella spp.(Klebsiella pneumoniae 93.2％)to imipenem and meropenem were 20.9％and 22.3％,respectively.Other Enterobacterales species were highly sensitive to carbapenem antibiotics.Only 1.7％-7.8％of other Enterobacterales strains were resistant to carbapenems.The resistance rates of Acinetobacter spp.(Acinetobacter baumannii 90.6％)to imipenem and meropenem were 68.4％and 70.6％respectively,while 28.5％and 24.3％of P.aeruginosa strains were resistant to imipenem and meropenem,respectively.Conclusions The number of clinical isolates from elderly patients is increasing year by year,especially in the 65-＜75 age group.Respiratory tract isolates were more prevalent in male elderly patients,and urinary tract isolates were more prevalent in female elderly patients.Klebsiella isolates were increasingly resistant to multiple antimicrobial agents,especially carbapenems.Antimicrobial resistance surveillance is helpful for accurate empirical antimicrobial therapy in elderly patients.

Aim To investigate the intervention effect of Rehmannia radix water extract on bleomycin(BLM)-induced pulmonary fibrosis in mice combined with metabolomics and to reveal the potential mechanism,in order to provide new ideas for clinical treatment of pul-monary fibrosis.Methods Male C57BL/6N mice were randomly divided into the control group,model group,pirfenidone group(positive control,PFD,270 mg·kg-1),and low dose(DH-L,4.55 g·kg-1)group,medium dose(DH-M,9.1 g·kg-1)group and high dose(DH-H,18.2 g·kg-1)group of Rehman-nia.Except for the control group,BLM(5 mg·kg-1)was instilled into the trachea to establish the model of pulmonary fibrosis in the other groups.The survival rate,lung index and blood oxygen saturation of mice in each group were evaluated.HE and Masson staining were used to observe the pathological changes of lung tissue.WBP was used to detect lung function.Flow cytometry was used to detect the apoptosis of primary lung cells,ROS and immune cells.ELISA was used to detect the levels of fibrosis markers and inflammatory factors(α-SMA,collagen Ⅰ,collagen Ⅲ,TGF-β1,TNF-α,IL-1 β,and IL-6).Biochemical method was employed to detect the contents of GSH-Px,T-SOD and MDA.Liquid chromatograph mass spectrometer(LC-MS)metabolomics was used to analyze the changes of serum metabolic profile.Results Water extract of Re-hmannia significantly increased the survival rate,oxy-gen saturation and lung function of mice with pulmona-ry fibrosis,reduced the lung coefficient,ameliorated pathological damage and collagen deposition in lung tissue,reduced the levels of apoptosis and oxidative stress,and down-regulated the levels of inflammatory factors in lung tissue.It regulated the levels of metabo-lites such as bile acid metabolism,sphingolipid metabo-lism,and unsaturated fatty acid metabolism.Conclu-sions Water extract of Rehmannia inhibits lung injury and collagen deposition in mice with pulmonary fibrosis by inhibiting inflammatory response,which may be a-chieved by regulating the levels of inflammatory factors through the metabolic pathways of bile acid and sphin-golipid.

Objective To explore the mechanism of honey-processed Hedysari Radix in the regulation of intestinal immunity in rats with spleen qi deficiency,which was based on G protein-coupled receptor 41(GPR41)/GPR43-mediated mitogen-activated protein kinase(MAPK)signaling pathway.Methods The three-factor composite modeling method of eating disorder,diarrhea and fatigue was used to establish a model of spleen qi deficiency,and the rats were randomly divided into model,honey-processed Hedysari Radix,probiotics and blank groups with 15 rats per group.The honey-processed Hedysari Radix group was given by gavage 12.6 g·kg-1 aqueous extract of honey-processed Hedysari Radix.The probiotics group was given 0.625 g·kg-1 bifidobacterium triple viable solution by gavage.The blank and model groups were given the same dose of distilled water by gavage.Four groups were treated for 15 d with once a day.The expression levels of GPR41,GPR43,P38 MAPK,c-Jun N-terminal kinase(JNK)and extracellular regulatory protein kinase 1/2(ERK1/2)in colon tissues were detected by Western blotting.Results The relative expression levels of GPR41 in the blank,model,honey-processed Hedysari Radix and probiotics groups were 0.95±0.07,0.45±0.03,0.84±0.19 and 0.86±0.20;the relative expression levels of GPR43 were 1.17±0.11,0.41±0.06,0.66±0.03 and 0.57±0.01;the phosphorylated ERK1/2/ERK1/2 ratios were 0.16±0.01,0.43±0.01,0.39±0.01 and 0.36±0.02;the phosphorylated JNK/JNK ratios were 0.58±0.05,1.47±0.10,0.90±0.11 and 0.90±0.11;the phosphorylated P38 MAPK/P38 MAPK ratios were 1.77±0.33,3.19±0.03,2.01±0.17 and 2.23±0.59,respectively.Compared with the model group,the differences of above indexes were statistically significant in the honey-processed Hedysari Radix and probiotics groups(P＜0.05,P＜0.01).Conclusion The mechanism of honey-processed Hedysari Radix regulating intestinal immunity in rats with spleen qi deficiency is related to the regulation of GPR41/GPR43 mediated MAPK signaling pathway.