Objective:To assess the clinical outcomes of dual-approach bicondylar fixation under adjustable positioning for Schatzker type IV trans-midline tibial plateau fractures.Methods:A retrospective cohort study was conducted to analyze the clinical data of 52 patients with Schatzker type IV trans-midline tibial plateau fractures admitted to First Affiliated Hospital to Nanjing Medical University from January 2014 to August 2023, including 37 males and 15 females, aged 19-68 years [(42.3±14.0)years]. All the patients were treated with the surgical scheme of anterior and medial dual-approach bicondylar internal fixation under adjustable positioning. The operation duration, intraoperative blood loss, and fracture healing time were counted. X-ray films were reviewed at 2 days after surgery for residual knee subluxation. At 2 days, 3 and 6 months after surgery, and at the last follow-up, the tibial plateau angle (TPA) and posterior slope angle (PA) were measured with follow-up X-ray films to evaluate whether there was loss of reduction. The knee function was evaluated with the American Hospital for Special Surgery (HSS) knee function score at 3 and 6 months after surgery and at the last follow-up. The anterior posterior displacement and rotation stability of the knee were evaluated with Lachman test and pivot-shift test at the last follow-up. The postoperative complications were recorded.Results:All the patients were followed up for 12-118 months [70(46, 85)months]. The operation duration was 100-180 minutes [145(120, 160)minutes], with intraoperative blood loss of 100-550 ml [(323.8±135.1)ml]. Fractures were healed well in all the patients, with the healing time of 2-4 months [3.0(2.4, 3.5)months]. None of the patients had residual subluxation by X-ray films at 2 days after surgery. There were no significant differences in TPA or PA at each time point after surgery ( P>0.05). The HSS knee function score was (69.4±4.9)points, (80.9±7.0)points, and (90.1±7.9)points at 3 and 6 months after surgery and at the last follow-up, respectively and the score gradually increased with the passage of time ( P<0.05). At the last follow-up, all the patients were negative in Lachman test and pivot-shift test. Three patients developed fat liquefaction around medial wounds after surgery, which were healed after dressing change. While the wounds were healed by first intention in the other patients. Postoperative complications such as knee instability, implant loosening, fracture or refracture not occurred. Conclusion:Dual-approach bicondylar fixation under adjustable positioning for Schatzker type IV trans-midline tibial plateau fractures has the advantages including high fracture healing rate, precise fracture reduction and fixation, satisfactory postoperative functional recovery and fewer complications, without increasing operation duration or intraoperative blood loss.

Objective:To assess the clinical outcomes of dual-approach bicondylar fixation under adjustable positioning for Schatzker type IV trans-midline tibial plateau fractures.Methods:A retrospective cohort study was conducted to analyze the clinical data of 52 patients with Schatzker type IV trans-midline tibial plateau fractures admitted to First Affiliated Hospital to Nanjing Medical University from January 2014 to August 2023, including 37 males and 15 females, aged 19-68 years [(42.3±14.0)years]. All the patients were treated with the surgical scheme of anterior and medial dual-approach bicondylar internal fixation under adjustable positioning. The operation duration, intraoperative blood loss, and fracture healing time were counted. X-ray films were reviewed at 2 days after surgery for residual knee subluxation. At 2 days, 3 and 6 months after surgery, and at the last follow-up, the tibial plateau angle (TPA) and posterior slope angle (PA) were measured with follow-up X-ray films to evaluate whether there was loss of reduction. The knee function was evaluated with the American Hospital for Special Surgery (HSS) knee function score at 3 and 6 months after surgery and at the last follow-up. The anterior posterior displacement and rotation stability of the knee were evaluated with Lachman test and pivot-shift test at the last follow-up. The postoperative complications were recorded.Results:All the patients were followed up for 12-118 months [70(46, 85)months]. The operation duration was 100-180 minutes [145(120, 160)minutes], with intraoperative blood loss of 100-550 ml [(323.8±135.1)ml]. Fractures were healed well in all the patients, with the healing time of 2-4 months [3.0(2.4, 3.5)months]. None of the patients had residual subluxation by X-ray films at 2 days after surgery. There were no significant differences in TPA or PA at each time point after surgery ( P>0.05). The HSS knee function score was (69.4±4.9)points, (80.9±7.0)points, and (90.1±7.9)points at 3 and 6 months after surgery and at the last follow-up, respectively and the score gradually increased with the passage of time ( P<0.05). At the last follow-up, all the patients were negative in Lachman test and pivot-shift test. Three patients developed fat liquefaction around medial wounds after surgery, which were healed after dressing change. While the wounds were healed by first intention in the other patients. Postoperative complications such as knee instability, implant loosening, fracture or refracture not occurred. Conclusion:Dual-approach bicondylar fixation under adjustable positioning for Schatzker type IV trans-midline tibial plateau fractures has the advantages including high fracture healing rate, precise fracture reduction and fixation, satisfactory postoperative functional recovery and fewer complications, without increasing operation duration or intraoperative blood loss.

Objective To investigate the inhibitory effects of pyruvate-ferredoxin oxidoreductase(PFOR)by luteolin and its anti-Clostridium difficile effect.Methods The PFOR encoding sequence of Clostridium difficile was cloned into the expression vector pET-2a and transformed into competent Escherichia coli.The crude enzyme was prepared after induction with IPTG(Isopropyl β-D-Thiogalactoside).The inhibitory rate of the test compounds on PFOR was determined after an 8-hour anaerobic reaction between PFOR and 40 μmol·L-1 of test compounds at 25℃.The minimum inhibitory concentration(MIC)of PFOR inhibitors against C.difficile strains(ATCC BAA 1382 and ATCC BAA 1870)was determined by monitoring the OD600 of the bacterial culture.Molecular docking was performed to investigate the possible interaction mechanisms between PFOR and inhibitors.Results Among the tested compounds,the luteolin showed the strongest inhibitory activity against PFOR,with a single-point inhibition rate of approximately 33%,which is comparable to that observed with the positive inhibitor nitazoxanide(40%).Molecular docking revealed that luteolin could form hydrogen bonds with Asp428,Val431,Gly429,Asp456,Lys458,Lys459,and other residues in the PFOR domain.The MIC of luteolin against C.difficile was approximately 32 μg·mL-1.Conclusion Luteolin exhibits good activity against C.difficile,and PFOR may be a target for its antibacterial action.

Fanconi anemia (FA) is an inheritable disorder that presents with bone marrow failure, developmental anomalies, and an increased susceptibility to cancer. The etiology of this condition stems from a genetic mutation that disrupts the proper repair of interstrand DNA cross-links (ICLs). The resultant dysregulation of the DNA damage response mechanism can induce genomic instability, thereby elevating the mutation rates and the likelihood of developing cancer. The FA pathway assumes a pivotal role in safeguarding genome stability through its involvement in the repair of DNA cross-links and the maintenance of overall genomic integrity. A mutation in the germ line of any of the genes responsible for encoding the FA protein results in the development of FA. The prevalence of aberrant FA gene expression in somatic cancer, coupled with the identification of a connection between FA pathway activation and resistance to chemotherapy, has solidified the correlation between the FA pathway and cancer. Consequently, targeted therapies that exploit FA pathway gene abnormalities are being progressively developed and implemented. This review critically examines the involvement of the FA protein in the repair of ICLs, the regulation of the FA signaling network, and its implications in cancer pathogenesis and prognosis. Additionally, it explores the potential utility of small-molecule inhibitors that target the FA pathway.

BACKGROUND:Ligaments are important structures in maintaining the stability of the lumbar spine,and these structures are prone to degradation due to the generated mechanical stress.However,there are few studies on ligament injuries. OBJECTIVE:To determine the range of motion and stress of each ligament in the state of motion based on a three-dimensional finite element model,and to systematically explore the influence of ligament injury on the stability of the lumbar spine and its biomechanical significance. METHODS:The L4-L5 lumbar finite element model was established.All free forces on the lower surface of L5 were constrained,and a torque of 5 N·m was applied to simulate the motion states of the lumbar spine.Progressive ligament damage was simulated by changing Young's modulus of the ligament. RESULTS AND CONCLUSION:(1)The extension range of motion of most ligament injuries increased significantly.In contrast,there was no significant change in the lateral bending range of motion.(2)The range of motion of capsular ligament injury increased significantly in flexion,extension and lateral bending.The extension range of motion increased significantly after the anterior longitudinal ligament injury.Intertransverse ligament injury resulted in a significant increase in the lateral bending range of motion.(3)After a single ligament injury,the most significant change in range of motion was observed during extension.After a single ligament injury,the stress of the remaining ligaments increased,especially the capsular ligament.The stress changes of the interspinous ligament and ligamentum flavum were the least obvious.Ligament stress changes least in lateral bending and most in torsion.(4)Ligament damage did not result in major changes in disc pressure,indicating that ligament injury leads to an increased range of motion of the lumbar spine and affects the stability of the lumbar spine.(5)Capsular ligament was stable in flexion,extension and lateral bending.The anterior longitudinal ligament showed a stable extension;the intertransverse ligament stabilizes the lateral curve.(6)Extension exercise is sensitive to a ligament injury,and the pathological changes of the ligament can be examined by extension exercise.(7)Stress compensation was given to the remaining ligaments to maintain the stability of the lumbar spine after a single ligament injury.(8)Interspinous ligament and ligamentum flavum injuries have the least impact on the peripheral ligaments,while capsular ligament injuries have the greatest impact on the peripheral ligaments.(9)The ligament injury has the least effect on the residual ligament stress during lateral bending exercise,while it has the greatest effect on the ligament stress during the twisting exercise.Patients with ligament injury should avoid twisting exercises.Ligament injuries do not affect disc pressure.

BACKGROUND:Establishing an objective and standard animal model of bone nonunion is essential for experimental studies and treatment of nonunion. OBJECTIVE:To establish an objective animal model for experimental studies of nonunion. METHODS:Specific pathogen-free male Wistar rats were selected and prepared by cutting off a 5 mm bone defect in the middle femur,peeling off a large periosteum and removing bone marrow.Animal models were fixed with a 1.2 mm Kirschner wire.At 1,4 and 8 weeks,bone nonunion was observed by gross specimen observation,X-ray examination and histopathological examination. RESULTS AND CONCLUSION:The gross specimen,X-ray film and histopathological examination showed that there was no callus formation in the bone defect area,the broken end was filled with fiber tissue,and the bone callus was rare or even invisible.To conclude,the rat model of nonunion can be successfully established by osteotomy of the middle femur,large periosteum peeling and bone marrow removal.This modeling method is simple,reliable and effective.

BACKGROUND:Ligaments are an important structure for stabilizing the lumbar spine,and they are prone to degenerative changes with age.Currently,there is limited research on lumbar ligaments. OBJECTIVE:To investigate the effect of different combinations of ligament injuries on biomechanical characteristics of lumbar spine under four motion states of forward bending,backward extension,lateral bending,and torsion under a certain sequence of ligament injuries. METHODS:A finite element model of the L4-L5 segment of the lumbar spine was established,and corresponding moments were applied to simulate four motion states of forward bending,backward extension,lateral bending,and torsion.The combined injuries of the ligaments were performed in order to obtain the motion range of each vertebra and the stress of each ligament. RESULTS AND CONCLUSION:(1)Every time a ligament was removed,the remaining ligament stress would increase.Under all four working conditions,capsular ligament would experience the highest stress,especially during forward bending.With the removal of ligaments,the range of motion of the vertebrae was also continuously increasing.(2)When flexing forward,after removing the first ligament capsular ligament,the average stress change in the remaining ligament was the highest,followed by the removal of supraspinous ligament.After removing capsular ligament,the change rate of range of motion was the highest,while after removing posterior longitudinal ligament,the change rate of range of motion was the lowest.(3)When extending backward,all ligaments had the highest rate of stress change after removing capsular ligament,the highest rate of range of motion change after removing capsular ligament,and the lowest rate of range of motion change after removing posterior longitudinal ligament.(4)When bending,the stress change rate of interspinous ligament decreased after removing intertransverse ligament,while supraspinous ligament increased more.After removing capsular ligament and interspinous ligament,the range of motion change rate increased significantly.(5)During lateral bending,after removing capsular ligament,the stress change rate of the remaining ligament was much higher than that of other ligament damage combinations,and the range of motion change rate was the highest after removing capsular ligament.In other cases,the range of motion change rate did not exceed 8%.(6)If the root ligament is damaged,the remaining ligaments will undergo stress compensation.Ligament damage will affect the stability of the lumbar spine,with minimal impact in cases of lateral curvature.Patients with lumbar instability should avoid forward flexion and backward extension movements,which can make it easier to detect the pathological condition of the ligaments.(7)Capsular ligament is an important structure for maintaining lumbar stability,and supraspinous ligament plays a significant role in anterior flexion,maintaining the integrity of the entire lumbar ligament.

OBJECTIVE To investigate the activation of xanthine oxidase(XO)from the human liver by vitamin K3 and the mechanism.METHODS Using human liver S9(0.1 g·L-1)as the source,XO was incubated with substrate xanthine of 0,2,4,8,and 16 μmol·L-1 at 37℃ for 90 min.The Michaelis constant(Km)of the reaction of xanthine oxidation was determined using the liquid chromatography diode array method.At the concentration of Km,the three-point method(1,10 and 100 μmol·L-1)was used to detect the activity of vitamin K3 activators.The multi-point method(vitamin K3 1,2,5,10,20,50,100,200 and 400 μmol·L-1)was adopted to determine the half effective concentration(EC50)of activated XO.Kinetic parameters(Km and Vmax)and the fit of double reciprocal curves were determined via vitamin K3 of 1/2EC50,EC50 and 2EC50.The changes in kinetic behavior at different concentrations of vitamin K3 were observed and their types of activation were analyzed.The interactions between XO and activator vitamin K3 were explored via molecular docking.RESULTS The Km of XO-mediated xanthine oxidation reac-tion was 4.71 μmol·L-1.As an activator of this reaction,vitamin K3 activated XO in a concentration-dependent manner(according to the logistic fitting formula y=A2+(A1-A2)/(1+(x/x0)^p),with an EC50 of 32.0 μmol·L-1.The kinetic parameters also changed after the addition of vitamin K3.The Km value decreased(4.71-1.34 μmol·L-1)with the increase of vitamin K3 concentrations,while the Vmax value increased(0.08-1.31 μmol·min-1·g-1),leading to an increase in Vmax/Km(17.0-977.6 mL·min·g-1).In addition,the double reciprocal curve fitting found that the activation type of vitamin K3 on XO was mixed.The molecular docking results showed that vitamin K3 bound to the molybdopterin domain of XO and maintained hydrogen bonding interactions with Arg599 and Ser605.CONCLUSION Vitamin K3 is an activator of XO,which can form hydrogen bonds with Arg599 and Ser605 in the XO domain,regu-late its affinity with the substrate xanthine,activate XO and increase the uric acid level.

Ankylosing spondylitis (AS) combined with lower cervical fracture is often categorized into unstable fracture, with a high incidence of neurological injury and a high rate of disability and morbidity. As factors such as shoulder occlusion may affect the accuracy of X-ray imaging diagnosis, it is often easily misdiagnosed at the primary diagnosis. Non-operative treatment has complications such as bone nonunion and the possibility of secondary neurological damage, while the timing, access and choice of surgical treatment are still controversial. Currently, there are no clinical practice guidelines for the treatment of AS combined with lower cervical fracture with or without dislocation. To this end, the Spinal Trauma Group of Orthopedics Branch of Chinese Medical Doctor Association organized experts to formulate Clinical guidelines for the treatment of ankylosing spondylitis combined with lower cervical fracture in adults ( version 2024) in accordance with the principles of evidence-based medicine, scientificity and practicality, in which 11 recommendations were put forward in terms of the diagnosis, imaging evaluation, typing and treatment, etc, to provide guidance for the diagnosis and treatment of AS combined with lower cervical fracture.

Objective Ionization chamber detector is commonly used for direct and continuous measurement of tritium concentration in the air. However, the measurement sensitivity is low due to the limitations of weak current measurement technology. It is necessary to develop a proportional counter for measuring tritium in the air. Methods This study involved the design of a proportional counter, considering various factors such as materials and structure. The stability, plateau curve, detection efficiency, and energy spectrum of the counter were tested. Results The coefficient of variation of the proportional counter was 3.14%, which met the standard requirement of being less than 15%. The plateau length was 260 V and the plateau slope was 0.80%/100V, which met the requirement of being less than 1%/100V. The tritium detection efficiency reached 68.02%. The energy spectrum measurement indicated a significant difference between tritium signal generated by the proportional counter and background signal, and the distribution of tritium in the energy spectrum was more concentrated. The background counting rate during tritium gas activity measurement could be reduced through energy spectrum measurement. Conclusion The proportional counter can provide a reference for the direct and continuous measurement of tritium in the air.