Intramedullary needle(IMN)has the advantages of high healing rate and low incidence of complications in treatment of tibial fracture,and has become one of the most commonly used fixation methods for the treatment of tibial fracture.However,due to the patient's own factors,fracture location and fracture type,infection and surgical treatment,bone nonunion after IMN still occurs in clinic.Bone nonunion leads to the increase of medical cost and prolonged the hospitalization time of patients,which causes great pain to patients,and also brings great challenges to the treatment of orthopedic surgeons.Therefore,this paper reviews the influencing factors of bone nonunion after IMN for tibial fracture,in order to provide reference for clinical treatment.

In mass spectrometry-based proteomics experiments,achieving high-throughput and efficientproteolytic digestion is crucial to ensure optimal protein cleavage and enhance the depth of protein identi-fication (including the number of identified proteins and the coverage of protein amino acid sequences) .Trypsin is the most widely used protease in mass spectrometry-based proteomics due to its ability to spe-cifically cleave the carboxyl terminus of arginine and lysine.However,it was found that Trypsin has some missed enzymatic efficiency for the cleavage of lysine residues.Therefore,in actual proteomics sample preparation,a combination of Trypsin and LysC will be used to ensure adequate cleavage of lysine resi-dues.Our study revealed that the commonly employed LysC-Trypsin tandem cleavage method exerts an impact on the enzymatic cleavage of protein samples by Trypsin due to the subsequent cleavage of Trypsin by initially added LysC.Consequently,we adjusted the order of LysC and Trypsin tandem digestion,with Trypsin cleavage being performed first followed by the addition of LysC to target any missed lysine resi-dues.We comprehensively compared and analyzed three distinct sequential digestion methods,namely Trypsin-Trypsin (T-T),LysC-Trypsin (L-T),and Trypsin-LysC (T-L),in terms of their effects on pro-tein sample preparation quality.The results demonstrated that the Trypsin-LysC sequential digestion ap-proach not only minimizes missed protein lysine/arginine cleavage sites without increasing experimental costs,at the same time yielding peptides with a moderate amino acid sequence length.The use of Tryp-sin-LysC digestion enhances the adsorption and separation of peptide samples in RP-HPLC,as well as improves the depth of protein detection and amino acid sequence coverage during tandem mass spectrome-try analysis.This research work offers a novel technical solution and serves as a valuable reference for proteome sample preparation.

Objective:To establish a method for preserving viral nucleic acids in plasma using a blood collection card based on the dry spot method,to predict the duration of nucleic acid preservation by establishing the Arrhenius equation,and to demonstrate the feasibility of this preservation method for the re-testing of nucleic acids in blood samples retained by blood banks.Methods:Plasma samples positive for HBV,HCV,and HIV nucleic acids were prepared into preservation cards in the form of dry plasma spots for storage.The prepared preservation cards were placed under accelerated storage conditions at 37,45,50,and 55 ℃.The preservation cards were periodically retrieved from each temperature condition for nucleic acid extraction,and the nucleic acid samples were purified for subsequent PCR testing,with the recorded CT values.An Arrhenius equation model was established between the expiration time and the storage temperature,thereby predicting the validity period of nucleic acid preservation in blood collection cards under specified storage temperature conditions.Results:For the plasma samples positive for HBV,HCV,and HIV nucleic acids preserved using the dry spot method,the regression equations for the duration with temperature were as follows:y=-11546x+31.74 for HBV,y=-12949x+36.88 for HCV,and y=-12204x+34.48 for HIV,with the correlation coefficient r greater than 0.98 for all.It was predicted that at a storage temperature of 4 ℃,the preservation periods for HBV,HCV,and HIV viral nucleic acids using the dry spot method would be 20792 days,19289 days,and 14285 days,respectively.At a storage temperature of 20 ℃,the preservation periods would be 2135 days 1502 days,and 1289 days,respectively.Conclusion:The nucleic acids of the three common viral pathogens in blood samples,when preserved using the dry spot method,conform to a first-order reaction pattern in the accelerated degradation experiment.The relationship between the rate of nucleic acid degradation and the absolute temperature of storage is consistent with the Arrhenius equation.Based on the calculations using this equation,the stability and validity period of plasma nucleic acid samples preserved using the dry spot method can reach a minimum of 3 .5 years under storage conditions not exceeding 20 ℃,which essentially meets the requirements for the preservation period of blood samples retained by blood banks.

Objective To clarify the understanding of types of laboratories and manufacturers for GB 9706.1-2020 Medical electrical equipment-Part 1:General requirements for basic safety and essential performance by laboratory proficiency testing for creepage distance and electrical clearance test.Methods An operation guide was formed according to the testing program in GB 9706.1-2020,and the homogeneity and stability of the samples were evaluated according to CNAS-GL003:2018 Guidance on Evaluating the Homogenneity and Stability of Samples Used for Proficiency Testing.Robust statistic methods were used to assess the quantitative parameters of the test results of the participating laboratories according to the requirements in GB/T 28043-2019 Statistical methods for use in proficiency testing by interlaboratory comparison;the results reported by the expert laboratories were used as the specified values of the qualitative parameters.SPSS 25.0 statistical software was used for data analysis.Results All the results of the crreepage distance and electrical clearance tests met the requirements for homogeneity and stability.Of the 46 laboratories involved in,37 ones did have comprehensive satisfactory determinations while the remained 9 ones not.Conclusion Some laboratories don't behave well in understanding the standard,which have to be reformed accordingly to enhance their proficiencies.[Chinese Medical Equipment Journal,2024,45(10):54-59]

Further evidence is needed to explore the impact of high-altitude environments on the neurologic function of neonates.Non-invasive techniques such as cerebral near-infrared spectroscopy and amplitude-integrated electroencephalography can provide data on cerebral oxygenation and brain electrical activity.This study will conduct multiple cerebral near-infrared spectroscopy and amplitude-integrated electroencephalography monitoring sessions at various time points within the first 3 days postpartum for healthy full-term neonates at different altitudes.The obtained data on cerebral oxygenation and brain electrical activity will be compared between different altitudes,and corresponding reference ranges will be established.The study involves 6 participating centers in the Chinese High Altitude Neonatal Medicine Alliance,with altitude gradients divided into 4 categories:800 m,1 900 m,2 400 m,and 3 500 m,with an anticipated sample size of 170 neonates per altitude gradient.This multicenter prospective cohort study aims to provide evidence supporting the impact of high-altitude environments on early brain function and metabolism in neonates.[Chinese Journal of Contemporary Pediatrics,2024,26(4):403-409]

Objective To establish the pharmacokinetic model of linezolid in neonates,and to optimize the administration regimen. Methods A prospective study was conducted among 64 neonates with sepsis who received linezolid as anti-infective therapy,and liquid chromatography-tandem mass spectrometry was used to measure the plasma concentration of the drug. Clinical data were collected,and nonlinear mixed effects modeling was used to establish a population pharmacokinetic (PPK) model. Monte Carlo simulation and evaluation was performed for the optimal administration regimen of children with different features. Results The pharmacokinetic properties of linezolid in neonates could be described by a single-compartment model with primary elimination,and the population typical values for apparent volume of distribution and clearance rate were 0.79 L and 0.34 L/h,respectively. The results of goodness of fit,visualization verification,and the Bootstrap method showed that the model was robust with reliable results of parameter estimation and prediction. Monte Carlo simulation results showed that the optimal administration regimen for linezolid in neonates was as follows:6 mg/kg,q8h,at 28 weeks of gestational age (GA);8 mg/kg,q8h,at 32 weeks of GA;9 mg/kg,q8h,at 34-37 weeks of GA;11 mg/kg,q8h,at 40 weeks of GA. Conclusions The PPK model established in this study can provide a reference for individual administration of linezolid in neonates. GA and body weight at the time of administration are significant influencing factors for the clearance rate of linezolid in neonates.

Objective To develop a prediction tool for post-endoscopic retrograde cholangiopancreatography(ER-CP)early biliary tract infection(PEEBI)in patients with choledocholithiasis,and assist clinical decision-making be-fore ERCP and early personalized intervention after ERCP.Methods An observational bidirectional cohort study was adopted to select inpatients with choledocholithiasis who underwent ERCP in a hospital.Directed acyclic graph(DAGs)and the least absolute shrinkage and selection operator(LASSO)were used to predict PEEBI based on lo-gistic regression,and the models were compared and validated internally and externally.Results From January 1,2020 to September 30,2023,a total of 2 121 patients with choledocholithiasis underwent ERCP were enrolled,of whom 77(3.6％)developed PEEBI,mostly in the first 2 days after surgery(66.2％).The major influencing fac-tors for PEEBI were non-iatrogenic patient-related factors,namely diabetes mellitus(OR=2.43,95％CI:1.14-4.85),bile duct malignancy(OR=3.95,95％CI:1.74-8.31)and duodenal papillary diverticulum(OR=4.39,95％CI:1.86-9.52).Compared with the LASSO model,the DAGs model showed higher ability(3.0％)in com-prehensive discrimination(P=0.007),as well as good differentiation performance(D=0.133,P=0.894)and cal-ibration performance(x2=5.499,P=0.703)in external validation.Conclusion The DAGs model constructed in this study has good predictive performance.With the help of this tool,targeted early preventive measures in clinical practice can be taken to reduce the occurrence of PEEBI.

Patients with severe trauma require an extremely timely treatment and transfusion plays an irreplaceable role in the emergency treatment of such patients. An increasing number of evidence-based medicinal evidences and clinical practices suggest that patients with severe traumatic bleeding benefit from early transfusion of low-titer group O whole blood or hemostatic resuscitation with red blood cells, plasma and platelet of a balanced ratio. However, the current domestic mode of blood supply cannot fully meet the requirements of timely and effective blood transfusion for emergency treatment of patients with severe trauma in clinical practice. In order to solve the key problems in blood supply and blood transfusion strategies for emergency treatment of severe trauma, Branch of Clinical Transfusion Medicine of Chinese Medical Association, Group for Trauma Emergency Care and Multiple Injuries of Trauma Branch of Chinese Medical Association, Young Scholar Group of Disaster Medicine Branch of Chinese Medical Association organized domestic experts of blood transfusion medicine and trauma treatment to jointly formulate Chinese expert consensus on blood support mode and blood transfusion strategies for emergency treatment of severe trauma patients ( version 2024). Based on the evidence-based medical evidence and Delphi method of expert consultation and voting, 10 recommendations were put forward from two aspects of blood support mode and transfusion strategies, aiming to provide a reference for transfusion resuscitation in the emergency treatment of severe trauma and further improve the success rate of treatment of patients with severe trauma.

Aim To investigate the effect of quercetin on the aging model of bone marrow mesenchymal stem cells established under microgravity. Methods Using 3D gyroscope, a aging model of bone marrow mesenchymal stem cells was constructed, and after receiving quercetin and microgravity treatment, the anti-aging effect of the quercetin was evaluated by detecting related proteins and oxidation indexes. Results Compared to the control group, the expressions of age-related proteins p21, pi6, p53 and RB in the microgravity group significantly increased, while the expressions of cyclin D1 and lamin B1 significantly decreased, with statistical significance (P<0.05). In the microgravity group, mitochondrial membrane potential significantly decreased (P<0.05), ROS accumulation significantly increased (P <0.05), SOD content significantly decreased and MDA content significantly increased (P<0.05). Compared to the microgravity group, the expressions of age-related proteins p21, pi6, p53 and RB in the quercetin group significantly decreased, while the expressions of cyclin D1 and lamin B1 significantly increased, with statistical significance (P<0.05). In the quercetin group, mitochondrial membrane potential significantly increased (P<0.05), ROS accumulation significantly decreased (P<0.05), SOD content significantly increased and MDA content significantly decreased (P<0.05). Conclusions Quercetin can resist oxidation, protect mitochondrial function and normal cell cycle, thus delaying the aging of bone marrow mesenchymal stem cells induced by microgravity.

This study constructed a LHCGR-CRE-luc-HEK293 transgenic cell line according to the activation of the cAMP signaling pathway after recombinant human chorionic gonadotropin binding to the receptor. The biological activity of recombinant human chorionic gonadotropin was assayed using a luciferase assay system. The relative potency of the samples was calculated using four-parameter model. And the method conditions were optimized to validate the specificity, relative accuracy, precision and linearity of the method. The results showed that there was a quantitative potency relationship of human chorinonic gonadotropin (hCG) in the method and it was in accordance with the four-parameter curve. After optimization, the conditions were determined as hCG dilution concentration of 2.5 μg·mL^-1, dilution ratio of 1∶4, cell number of 10 000-15 000 cells/well, and induction time of 6 h. The method had good specificity, relative accuracy with relative bias ranging from -8.9% to 3.4%, linear regression equation correlation coefficient of 0.996, intermediate precision geometric coefficient of variation ranging from 3.3% to 15.0%, and linearity range of 50% to 200%. This study successfully established and validated a reporter gene method to detect hCG biological activity, which can be used for hCG biological activity assay and quality control.