1.Feasibility of acceptance of multiple accelerators using Elekta AGL standard procedures
Liang ZHAO ; Guiyuan LI ; Xiaohong WAN ; Xinyuan CHEN ; Kuo MEN ; Jianrong DAI ; Yuan TIAN
Chinese Journal of Radiation Oncology 2024;33(3):244-249
Objective:To verify the feasibility of using Elekta accelerated go live (AGL) standard process for the acceptance of multiple accelerators.Methods:The beams of three accelerators were adjusted by PTW Beamscan three-dimensional water tank to reach the AGL standard. Dose verification was performed for three accelerators that met AGL standards. A simple field test example from Cancer Hospital Chinese Academy of Medical Sciences was used to compare the MapCheck 3 surface dose measurement results with the surface dose calculated by the same accelerator model. Images of 10 patients including head and neck, esophagus, breast, lung and rectum were randomly selected. volumetric-modulated arc therapy (VMAT) and intensity modulated radiation therapy (IMRT) treatment techniques were used for planning design, and the measured dose of ArcCheck was compared with the planned dose calculated by the same accelerator model. One-way ANOVA was used to statistically analyze the passing rates of two-dimensional and three-dimensional dose verification.Results:The 6 MV X-ray percentage depth dose at 10 cm underwater (PDD 10) of three accelerators was 67.45%, 67.36%, 67.47%, and the maximum deviation between the three accelerators was 0.11%. The 6 MV flattenting filter free (FFF) mode X-ray PDD 10 was 67.33%, 67.20%, 67.20%, and the maximum deviation between the three accelerators was 0.13%. All required discrete point doses on each energy 30 cm×30 cm Profile spindle of the three accelerator X-rays deviated less than ±1% from the standard data. Absolute γ analysis was performed on the results of MapCheck 3 two-dimensional dose matrix validation. Under the 10% threshold of 2 mm/3% standard, the average passing rate of the test cases in Cancer Hospital Chinese Academy of Medical Sciences was above 99%, and the difference was not statistically significant ( P>0.05). Absolute γ analysis was performed on the ArcCheck verification results. Under the 10% threshold, the pass rate of 2 mm/3% was all above 95%, the maximum average passing rate of the three accelerators with different energy and different treatment techniques was 0.28% (6 MV, VMAT), 0.19%(6 MV FFF, VMAT), 0.56% (6 MV, IMRT) and 0.05% (6 MV FFF, IMRT), and the difference was not statistically significant ( P>0.05). Conclusion:Compared with traditional accelerator acceptance process, the acceptance time of each accelerator is shortened by 4-6 weeks by using the AGL standard process, and the radiotherapy plan of patients can be interchangeably executed among different accelerators.
2.Effect of microwave on adenovirus capsid integrity and antigenicity of hexon protein in simulated infectious wastes
Kuo WANG ; Shujun DING ; Dandi LI ; Xiaobin YANG ; Zeming QIN ; Li ZHAO ; Liuying TANG
Chinese Journal of Experimental and Clinical Virology 2024;38(3):247-251
Objective:To investigate the effect of microwave on human adenovirus type 2 (HAdV-2) capsid protein in simulated infectious wastes.Methods:Droplets of HAdV-2 virus suspension were added to medical disposable gloves to simulate infectious waste, irradiated under different microwave conditions, the temperature change was recorded, and the irradiated viral supernatant was treated with Dnase I and detected by PCR and qPCR to determine the effect of microwave on the integrity of the viral capsid. ELISA was used to detect the effect of microwave irradiation on the structure of viral hexon protein. The virus was treated alone at the highest temperature during microwave irradiation to investigate whether there were non-thermal effects during microwave disinfection.Results:The maximum temperature during microwave irradiation was 76 ℃, and the PCR and qPCR result showed that Dnase I could significantly damage the viral nucleic acid after microwave irradiation, while the virus control group and heat treatment group were not significantly affected, indicating that microwave irradiation could destroy the integrity of the viral capsid. The result of ELISA showed that microwave irradiation could significantly weaken the binding ability of Hexon protein and antibody, and the result of heat treatment group were similar.Conclusions:Microwave irradiation can destroy the integrity of the HAdV-2 capsid and the structure of Hexon protein, in which the damage to the integrity of the capsid is mainly due to non-thermal effects, and the structural changes of hexon protein are mainly due to thermal effects.
3.Research progress on the relationship between miRNA and fracture healing
Peiyuan WANG ; Kuo ZHAO ; Zhiang ZHANG ; Wei CHEN ; Zhiyong HOU ; Lin JIN
Journal of Chinese Physician 2024;26(10):1593-1597
Fracture is a disease caused by violence or bone disease in which the continuity of bone structure is completely or partially broken. The healing of fracture mainly includes three processes: hematoma mechanization stage, callus formation stage and callus remodeling stage. At different stages, various cells and molecules are important factors regulating fracture healing. There is growing evidence that miRNA plays an important role in various bone diseases, such as osteosarcoma, osteoarthritis, osteonecrosis, and fractures. Recent studies have shown that miRNA can regulate the process of fracture healing and may be potential biomarkers of fracture healing. This article reviews the expression, function and mechanism of miRNA in the process of fracture healing.
4.Simulation study of proton radiography based on pixel sensors
Minghui LI ; Yilun CHEN ; Hu RAN ; Jianrong DAI ; Kuo MEN ; Chengxin ZHAO ; Chuanmeng NIU ; Hongkai WANG
Chinese Journal of Medical Physics 2024;41(9):1064-1069
Using high-energy proton to image the region of interest can directly obtain the accurate estimation of the proton stopping power of the lesions,which is of great significance to reduce the range uncertainty in proton therapy.As a fundamental function of proton computed tomography(CT),radiographic imaging plays a crucial role in assisting clinical positioning.The study develops a compact proton CT detector based on an active array pixel CMOS chip in Monte-Carlo simulation toolkit Geant4,and evaluates the radiographic imaging capability of the system using 180 MeV protons.The angles of tracks are successfully reconstructed.CTP404,CTP528,and the CTP515 of specific materials are used for simulation,obtaining the spatial and density resolutions,and measuring the proton relative stopping power(RSP).The image signal-to-noise ratio is improved when using 2° proton scattering angle cut-off value.The spatial resolution is 3-4 lp/cm measured using CTP528 module.The density resolution is better than 0.05 g/cm3,and the RSP resolution is within 5%when CTP404 module is used.Through the imaging of CTP515 phantom of specific material,it is demonstrated that the system has potential for imaging common human tissues.
5.Efficacy of internal fixation using cannulated screw combined with fibular allograft in the treatment of femoral neck fracture in young and middle-aged patients
Peiyuan WANG ; Ziping LI ; Zhiang ZHANG ; Zhenqing JIAO ; Kuo ZHAO ; Lin JIN ; Zhiyong HOU
Chinese Journal of Trauma 2024;40(9):801-808
Objective:To compare the efficacy of internal fixation using cannulated screw combined with fibular allograft and internal fixation using cannulated screw alone in the treatment of femoral neck fracture in young and middle-aged patients.Methods:A retrospective cohort study was conducted to analyze the clinical data of 75 young and middle-aged patients with femoral neck fracture admitted to the Third Hospital of Hebei Medical University from January 2020 to December 2022, including 44 males and 31 females, aged 34-56 years [(46.1±12.7)years]. According to Garden classification, 26 patients were classified as type II, 35 type III and 14 type IV. According to the Pauwels classification, 9 patients were classified as type I, 31 type II and 35 type III. Forty-nine patients were treated with internal fixation using three cannulated screws alone (cannulated screw group) and 26 with internal fixation using three cannulated screws combined with double-barrel fibular allograft (cannulated screw combined with bone grafting group). The operation time, intraoperative blood loss, length of hospital stay, and quality of fracture reduction were compared between the two groups. At 4, 8 months after operation and at the last follow-up, grading of femoral neck shortening, number of patients walking with crutches, Barthel index, and Harris hip function score were evaluated. The incidence of complications was measured at the last follow-up.Results:All the patients were followed up for 16-37 months [(23.2±4.5)months]. The operation time of the cannulated screw combined with bone grafting group was (86.3±16.1)minutes, longer than (76.9±20.8)minutes of the cannulated screw group ( P<0.05). The intraoperative blood loss was 100.0(50.0, 200.0)ml in the cannulated screw combined with bone grafting group, more than 50.0(50.0, 100.0)ml in the cannulated screw group ( P<0.01). There were no significant differences in the length of hospital stay or the quality of fracture reduction between the two groups ( P>0.05). At 4 months after operation, grading of the femoral neck shortening in the cannulated screw combined with bone grafting group [24 patients (92.3%) with grade 1, 2(7.7%) with grade 2, and 0(0.0%) with grade 3] was better than that in the cannulated screw group [18 patients (36.7%) with grade 1, 28(57.1%) with grade 2, and 3(6.2%) with grade 3] ( P<0.01). At 8 months after operation, grading of femoral neck shortening in the cannulated screw combined with bone grafting group [22 patients (84.6%) with grade 1, 3(11.5%) with grade 2, and 1(3.8%) with grade 3] was better than that in the cannulated screw group [13 patients (26.5%) with grade 1, 27(55.1%) with grade 2, and 9(18.4%) with grade 3] ( P<0.01). At the last follow-up, grading of femoral neck shortening in the cannulated screw combined with bone grafting group [19 patients (73.0%) with grade 1, 5(19.2%) with grade 2, and 2(7.6%) with grade 3] was better than that in the cannulated screw group [8 patients (16.3%) with grade 1, 31(63.2%) with grade 2, and 10(20.4%) with grade 3] ( P<0.01). At 4, 8 months after operation and at the last follow-up, 12(46.2%), 8(30.8%) and 5(19.2%) patients in the cannulated screw combined with bone grafting group and 38(77.6%), 27(55.1%) and 20(40.8%) patients in the cannulated screw group had to walk with crutches, respectively, showing significant difference between the two groups at the other two time points ( P<0.05 or 0.01) except for at the last follow-up ( P>0.05). The Barthel index values were 85.3±3.2, 90.3±4.3, and 95.3±3.9 in the cannulated screw combined with bone grafting group at 4, 8 months after operation and at the last follow-up, significantly higher than 80.8±7.3, 85.4±7.4, and 90.9±7.8 in the cannulated screw group ( P<0.05 or 0.01). The Harris hip scores were (87.0±2.9)points, (92.0±2.9)points and (91.3±2.4)points in the cannulated screw combined with bone grafting group at 4, 8 months after operation and at the last follow-up, significantly higher than (81.0±6.1)points, (85.7±5.8)points, and (89.6±2.0)points in the cannulated screw group ( P<0.01). At the last follow-up, the complication rate was 3.8%(1/26) in the cannulated screw combined with bone grafting group, significantly lower than 22.4%(11/49) in the cannulated screw group ( P<0.05). Conclusion:For femoral neck fractures in young and middle-aged patients, compared with internal fixation using cannulated screw alone, internal fixation using cannulated screw combined with fibular allograft has more advantages in correcting femoral neck shortening, restoring independent living activities and hip joint function, and reducing the incidence of complications despite its longer operation time and more intraoperative blood loss.
6.Protective Effect of Huazhuo Jiedu Huoxue Tongluo Prescription on Cerebral Ischemia-reperfusion Injury via Regulating Autophagy Based on JNK Signaling Pathway
Minhan ZHAO ; Xinqiao CHU ; Xiaohui CAO ; Ruiqing HUO ; Kuo SUN ; Fangzhao LI ; Yufan HAN ; Junbiao TIAN
Chinese Journal of Experimental Traditional Medical Formulae 2023;29(7):115-125
ObjectiveTo investigate the mechanism of Huazhuo Jiedu Huoxue Tongluo prescription in alleviating cerebral ischemia-reperfusion injury via regulating nerve cell autophagy based on c-Jun N-terminal kinase(JNK)signaling pathway . MethodSixty SD rats were randomly divided into 6 groups: sham group, middle cerebral artery occlusion/reperfusion (MCAO/R) group (model group), Huazhuo Jiedu Huoxue Tongluo prescription group [traditional Chinese medicine (TCM) group(25.0 g·kg-1)], JNK inhibitor SP600125 (SP) group(5 mg·kg-1), TCM+SP group and JNK agonist Anisomycin (Ani) group(15 mg·kg-1). After 24 h of modeling, TCM group and TCM+SP group were given TCM decoction (ig) for 3 consecutive days, and the other groups were given equal volume of normal saline (ig). Neurological deficit was evaluated by neurological function score and cerebral infarct volume was determined by 2,3,5-triphenyltetrazole chloride (TTC) staining. Hematoxylin-eosin (HE) staining and Nissl staining were used to observe the structural changes of brain tissue and the damage of neurons, respectively. Terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling assay (TUNEL) was performed to detect cell apoptosis. The ultrastructure of autophagosomes was observed by transmission electron microscope. Western blot was employed to detect the protein expressions of microtubule-associated protein 1 light chain 3A/B (LC3A/B), autophagy related 5 (Atg5), the ortholog of yeast Atg6 (Beclin1), p62, B-cell lymphoma 2 (Bcl-2), JNK, phosphorylated (p)-JNK and c-Jun in brain tissue. The mRNA expressions of LC3A/B, Beclin1, p62, Atg5, Bcl-2, JNK and c-Jun were detected by Real-time fluorescence quantitative polymerase chain reaction (Real-time PCR). ResultCompared with the sham group, the model group had elevated neurological deficit score (P<0.05), enlarged cerebral infarct volume (P<0.05)and typical infarction manifestations formed in hippocampal region and its surrounding brain tissue. In addition, there were a large number of neuronal cell degeneration, necrosis, liquefaction, nucleus pyknosis and deep staining, and inflammatory cell infiltration in the cortex in the model group, and severe swelling of mitochondria, lysosomes, autophagosomes and autophagolysosomes were clearly seen under electron microscope. TUNEL positive cells were increased (P<0.05), and cell apoptosis was severe. The nuclear membrane and nucleolus of neurons in brain tissue were blurred with discontinuous processes, and Nissl bodies in cytoplasm were stained light with reduced number. Western blot revealed that the model group had up-regulated protein expressions of LC3A/B, Beclin1, Atg5, JNK, p-JNK and c-Jun in brain tissue (P<0.05), while down-regulated protein expressions of p62 and Bcl-2 (P<0.05)as compared with the sham group. Real-time PCR indicated that the mRNA expressions of LC3A/B, Beclin1, Atg5, JNK and c-Jun in the model group were higher (P<0.05) while the mRNA expressions of p62 and Bcl-2 were lower (P<0.05) than those in the sham group. Compared with the conditions in model group, the neurological deficit scores of TCM, SP and TCM+SP groups were lowered (P<0.05), and the cerebral infarct volume was reduced (P<0.05), with improved pathological status of brain tissue, especially in the TCM group. Furthermore, there were abundant and basically normal mitochondrial cristae, slightly dilated endoplasmic reticulum, slightly swollen golgi apparatus, slightly fused nuclear membrane, and few visible lysosomes, autophagosomes and autophagolysosomes. TUNEL positive cells were decreased (P<0.05), displaying reduced apoptosis, especially in the TCM group. The nucleolus and nuclear membrane of neurons in brain tissue were discernible, and Nissl bodies in cytoplasm was reduced to a certain degree as compared with those in the model group. Western blot showed a decrease in the protein expressions of LC3A/B, Beclin1, Atg5, JNK, p-JNK and c-Jun in the TCM group ,the SP group,and the TCM+SP group(P<0.05),while an increase in the protein expressions of p62 in the TCM group and SP group(P<0.05),and an increase in the protein expressions of Bcl-2 in the TCM group and TCM+SP group. By Real-time PCR, the mRNA expressions of LC3A, LC3B, Beclin1, Atg5, JNK and c-Jun had a down-regulation(P<0.05) while the mRNA expression of p62 a up-regulation in the TCM group ,the SP group,and the TCM+SP group(P<0.05),and the mRNA expression of Bcl-2 a up-regulation in the TCM group and the TCM+SP group(P<0.05).Scores of the Ani group were raised (P<0.05), and infarct volume was increased significantly, with aggravated neuronal cell necrosis and obvious inflammatory infiltration. Moreover, there were neuronal nuclear membrane fusion with abnormal protrusion, increased heterochromatin aggregation in edge, severe mitochondrial swelling, endoplasmic reticulum expansion, increased lysosomes, increased intracytoplasmic vesicles, and visible autophagosomes and autophagolysosomes. TUNEL positive cells were increased (P<0.05), representing severe apoptosis. The number of Nissl bodies dropped with light staining, and the nucleolus and nuclear membrane were blurred. Real-time PCR found that the mNRA expressions of Atg5, c-Jun, JNK were up-regulated (P<0.05),while Beclin1, p62, Bcl-2 were were down-regulated in the Ani group (P<0.05). Compared with the TCM group and SP group,the protein expressions of LC3A/B, Beclin1, Atg5, JNK, p-JNK, c-Jun were decreased,and p62, Bcl-2 were increased in the Ani group(P<0.05). Compared with the TCM group,the mRNA expressions of JNK mRNA had a down-regulation in the SP group and TCM+SP group,while LC3A, LC3B, Atg5, c-Jun, JNK had an up-regulation(P<0.05) and Bcl-2 had a down-regulation in the Ani group(P<0.05). Compared with the SP group,the mRNA expressions of Atg5, c-Jun, JNK had an up-regulation(P<0.05), and Beclin1, p62, Bcl-2 had a down-regulation in the Ani group(P<0.05). ConclusionHuazhuo Jiedu Huoxue Tongluo prescription significantly up-regulates the protein and mRNA expressions of LC3A/B, Beclin1, Atg5, JNK, p-JNK and c-Jun, and down-regulates the protein and mRNA expressions of p62 and Bcl-2, suggesting that the prescription can inhibit autophagy through JNK signaling pathway to reduce ischemia/reperfusion injury in rats.
7.Highly efficient production of L-valine by multiplex metabolic engineering of Corynebacterium glutamicum.
Kuo ZHAO ; Jinyu CHENG ; Liang GUO ; Cong GAO ; Wei SONG ; Jing WU ; Jia LIU ; Yadi LIU ; Liming LIU ; Xiulai CHEN
Chinese Journal of Biotechnology 2023;39(8):3253-3272
As a branched chain amino acid, L-valine is widely used in the medicine and feed sectors. In this study, a microbial cell factory for efficient production of L-valine was constructed by combining various metabolic engineering strategies. First, precursor supply for L-valine biosynthesis was enhanced by strengthening the glycolysis pathway and weakening the metabolic pathway of by-products. Subsequently, the key enzyme in the L-valine synthesis pathway, acetylhydroxylate synthase, was engineered by site-directed mutation to relieve the feedback inhibition of the engineered strain. Moreover, promoter engineering was used to optimize the gene expression level of key enzymes in L-valine biosynthetic pathway. Furthermore, cofactor engineering was adopted to change the cofactor preference of acetohydroxyacid isomeroreductase and branched-chain amino acid aminotransferase from NADPH to NADH. The engineered strain C. glutamicum K020 showed a significant increase in L-valine titer, yield and productivity in 5 L fed-batch bioreactor, up to 110 g/L, 0.51 g/g and 2.29 g/(L‧h), respectively.
Valine
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Corynebacterium glutamicum/genetics*
;
Metabolic Engineering
;
Amino Acids, Branched-Chain
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Bioreactors
8.The inactivation effects of microwave on human adenovirus in simulated infectied wastes and the molecular mechanism
Kuo WANG ; Dandi LI ; Shiyan LIU ; Zhu YANG ; Chang LIU ; Xiaobin YANG ; Zeming QIN ; Shujun DING ; Liuying TANG ; Li ZHAO
Chinese Journal of Experimental and Clinical Virology 2023;37(5):511-517
Objective:To study the inactivation effects of microwave on human adenovirus 2 (HAdV-2) in simulated infectied wastes, and to explore its molecular mechanism.Methods:25 μl of HAdV-2 virus suspension was dripped with medical disposable gloves, masks and cotton swabs to simulate infectied wastes, and irradiated under different microwave conditions: gloves and masks were irradiated for 30 s, 60 s, and 90 s at 300 W, 500 W, and 700 W, respectively. Cotton swabs irradiate 60 s, 90 s, 120 s at 500 W and 700 W respectively. Temperature changes were recorded, and the inactivation logarithmic values were calculated by the 50% endpoint method to evaluate the microwave inactivation effects, and the proliferation ability of the virus was detected by qPCR. The damage of Penton, Fiber, Hexon and E2 B genes was detected by PCR. The virus was treated with the highest temperature of 76 ℃ during microwave irradiation to study whether there was non-thermal effect during microwave disinfection. Results:After microwave irradiation of infectied waste, the temperature of masks and gloves carriers rises rapidly, with the highest temperature of 76 ℃. The temperature of the cotton swab carriers rose slowly, and the highest temperature is 65 ℃. The inactivation effect of microwave on HAdV-2 was positively correlated with microwave power and irradiation time. In the mask and glove group, microwave power of 700 W irradiated for 60 seconds, and the inactivation logarithm value could reach 3.0, In the cotton swab group, microwave power of 700 W irradiated for 120 seconds, and the inactivation logarithm value was still less than 3.0. This indicated that there were differences in the conditions for microwave inactivation of the virus in different carriers. The qPCR result showed that microwave irradiation could weak the proliferation ability of the virus. Microwave irradiation had no effect on the virus's Penton and Fiber genes, but caused some damage to the Hexon and E2 B genes. The inactivation effect of individual heat treatment on HAdV-2 was weaker than that of microwave irradiation, and there was no damage to the Hexon, Penton, Fiber, and E2 B genes. This indicated the presence of non thermal effects during the microwave inactivation process. Conclusions:Microwave irradiation can inactivate HAdV-2 in simulated infectied wastes through thermal and non-thermal effects, and its damage to viral DNA is one of the mechanisms of virus inactivation.
9.Effect of Huazhuo Jiedu Huoxue Tongluo Prescription on Brain-gut Axis of Rats with Cerebral Ischemia-reperfusion Injury Based on 16S rRNA Sequencing of Intestinal Flora
Rui-qing HUO ; Min-han ZHAO ; Fang-zhao LI ; Yu-fan HAN ; Kuo SUN ; Jun-biao TIAN
Chinese Journal of Experimental Traditional Medical Formulae 2022;28(1):121-130
ObjectiveTo study the effect of Huazhuo Jiedu Huoxue Tongluo (HJHT) prescription on the intestinal flora in rats with cerebral ischemia-reperfusion injury, and to explore the mechanism of Chinese medicinal prescription regulating intestinal flora to restore the balance of brain-gut axis. MethodFifty male SPF SD rats were randomly assigned into sham group, model group, high-dose HJHT group (25.0 g·kg-1), medium-dose HJHT group (12.5 g·kg-1), and low-dose HJHT group (6.25 g·kg-1), with 10 rats in each group. The rat model of permanent middle cerebral artery infarction was established according to Longa method and previous research experience, and reperfusion was performed 2 h after ischemia. The recovery of neurological function deficit and the percentage of cerebral infarction area were detected 72 h after administration. Real-time PCR was performed to detect the mRNA levels of Occludin and zonula occludens-1 (ZO-1) in rat colon. Hematoxylin-eosin (HE) staining was conducted to reveal the intestinal damage. The feces of 6 rats in each group were collected for 16S rRNA sequencing. The expression of Treg and Th17 in intestinal tissue, peripheral blood, and brain tissue were detected. ResultCompared with the sham group, the model group showed obvious neurological deficit (P<0.05) and large cerebral infarction area (P<0.05). High-dose and medium-doses HJHT alleviated the symptoms of neurological impairment (P<0.05) and reduce the cerebral infarction area (P<0.05) compared with the model group. Compared with the sham group, the model group showed destroyed structure of colonic mucosa and incomplete epithelial cells and goblet cells, while high-dose and medium-doses HJHT alleviated such changes. The mRNA levels of Occludin and ZO-1 in the model group were lower than those in the sham group (P<0.05),and the high-dose HJHT groups were higher than the model group (P<0.05). The intestinal flora structure was significantly different between the model group and the sham group while similar between the high-dose HJHT group and sham group. Compared with the sham group, the model group showed down-regulated expression of Treg and up-regulated expression of Th17 in the intestinal tissue, peripheral blood, and brain tissue, and high-dose and medium-dose HJHT alleviated the changes in the expression of Treg and Th17 in the model group (P<0.05). ConclusionHuazhuo Jiedu Huoxue Tongluo prescription may improve the permeability of intestinal wall by adjusting the abundance and diversity of intestinal microorganisms to reduce the migration of intestinal Th17 cells toward the ischemic lateral brain tissue, mitigate the inflammatory response, and thus alleviate the cerebral ischemia-reperfusion injury in rats.
10.Treatment of intra-articular distal femur fracture by our slot-designed compression bolt combined with bilateral locking compression plates: a biomechanical analysis
Junzhe ZHANG ; Hongyu MENG ; Junyong LI ; Xiaodong LIAN ; Kuo ZHAO ; Yanbin ZHU ; Wei CHEN ; Yingze ZHANG
Chinese Journal of Orthopaedic Trauma 2022;24(5):380-384
Objective:To evaluate the biomechanical stability of our slot-designed compression bolt (SCB) combined with bilateral locking compression plates (LCPs) in the treatment of intra-articular distal femur fracture.Methods:In 24 adult male knee specimens treated with formalin, the femoral bony part was preserved to establish standard models of intra-articular distal femur fracture (AO type 33-C1). According to the random number table, the fracture models were divided into 2 equal groups: an experimental group ( n=12) subjected to fixation with one SCB combined with bilateral LCPs with 10 locking screws and a control group ( n=12) subjected to fixation with bilateral LCPs with 12 locking screws. In each model, a vertical ballast test was conducted to record the maximum axial displacement of the system and a horizontal torsion test to calculate the torsional stiffness of the system. When the loading pressure was 0-1,000 N in the biomechanical machine, structural abnormalities were observed in the 2 groups of models and the system maximum axial displacement and system torsional stiffness were compared between the 2 groups. Results:When the vertical ballast pressure was 400 N, 600 N, 800 N and 1,000 N, the maximum axial displacement of the system was, respectively, (0.14±0.01) mm, (0.25±0.01) mm, (0.41±0.02) mm and (0.63 ± 0.02) mm in the experimental group, and (0.15 ± 0.01) mm, (0.26 ± 0.01) mm, (0.46 ± 0.03) mm, and (0.67 ± 0.04) mm in the control group. Compared with the control group, the average maximum axial displacement in the experimental group decreased significantly under the axial pressure of 600-1,000 N ( P<0.05). When the horizontal torsion reached 5°, the torsional stiffness was, respectively, (2.00±0.12) Nm/° and (2.02±0.07) Nm/° in the experimental group and the control group, showing no significant difference between the 2 groups ( P>0.05). Conclusions:In the treatment of intra-articular distal femur fracture, compared with simple bilateral LCPs, our SCB combined with bilateral LCPs demonstrate similar torsional stability but better axial biomechanical stability. As our SCB has advantages of bilateral compression and minimal invasion in operation, it may be a new option for the reduction and compression treatment of intra-articular fractures.

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