[摘 要] 目的：探讨甲硫氨酸限制对肺腺癌（LUAD）细胞增殖、凋亡及磷酸戊糖途径的影响。方法：将H1299、A549细胞分为Met+组和Met−组，分别用含100 μmol/L或不含甲硫氨酸的培养基连续培养4 d，采用细胞计数法评估甲硫氨酸处理对H1299和A549细胞增殖的影响，PI染色法检测细胞周期分布，Annexin Ⅴ-PE/7AAD标记细胞凋亡，利用DCFH-DA探针检测细胞内ROS水平，WST-8法和DTNB法分别测定细胞内NADPH与GSH含量；通过癌症基因组图谱（TCGA）数据库分析葡萄糖-6-磷酸脱氢酶（G6PD）和6-磷酸葡萄糖酸脱氢酶（6PGD）表达与甲硫氨酸代谢通路的关系；采用WB法检测甲硫氨酸处理及回补甲硫氨酸下游代谢产物S-腺苷甲硫氨酸（SAM）对LUAD细胞中磷酸戊糖途径关键酶G6PD和6PGD表达的影响。结果：甲硫氨酸限制显著抑制H1299和A549细胞增殖（均P < 0.01），将细胞周期阻滞于G2/M期（均P < 0.05），显著升高细胞内总ROS水平（均P < 0.001）并促进细胞凋亡（均P < 0.001）；同时，甲硫氨酸限制显著降低了细胞内NADPH和GSH水平（均P < 0.01），抑制DNA合成（均P < 0.01）。分析TCAG数据发现，G6PD和6PGD表达水平与甲硫氨酸代谢通路呈正相关（均P < 0.001），甲硫氨酸限制下调G6PD和6PGD蛋白表达（均P < 0.01），而回补SAM可部分逆转甲硫氨酸限制对G6PD和6PGD的表达的抑制（均P < 0.01），提示甲硫氨酸通过SAM合成调控磷酸戊糖途径。结论：甲硫氨酸限制通过抑制磷酸戊糖途径抑制LUAD细胞增殖，为甲硫氨酸限制疗法治疗LUAD提供实验依据。

Objective To develop a three-compartment kinetic fatigue model for the isometric muscle endurance of the hip,knee,and ankle joints at 50％IPT(isometric peak torque),so as to provide a theoretical basis for simulation-based assessments and load evaluations in biomechanics and sports science.Methods The IPT of the hip,knee,and ankle joints was measured in 40 male university students.Isometric endurance tests were then performed on all three joints at 50％IPT until exhaustion.Electromyography data and endurance time(ET)of major lower limb muscles were collected concurrently.The differences between ETs predicted by models based on previously recommended F and R parameters and actual ETs were analyzed.Subsequently,experimental ETs were used in a grid search to optimize Fand R parameters,allowing for the development of an accurate three-compartment kinetic model.Results The ET of the hip and ankle joints was significantly longer than that of the knee joint(P＜0.001).Models using previously recommended Fand R parameters overestimated ET,with significantly higher predicted values than experimentally measured ET(P＜0.001),as well as elevated root mean squared error(RMSE)and mean relatvie error(MRE)values.The grid search successfully identified Fand R parameters for the three-compartment model in isometric endurance tests of lower limb joints,with no statistical difference between model-predicted ET and experimental ET(P＞0.05).Conclusions The developed model in this study can serve as an indirect measurement tool for evaluating load in similar activities.

Objective:To investigate the effects of repetitive transcranial magnetic stimulation(rTMS) on learning memory and abnormal Aβ deposition in cerebral amyloid angiopathy(CAA) model mice, and further to investigate whether the mechanism involves the transport function of glymphatic system.Methods:Eight-month-old SPF grade Tg-SWDI mice were randomly divided into the CAA group and the rTMS group according to the random number table method with 7 in each group.Seven wild-type mice of the same genetic background and age served as the control group. The mice in rTMS group received two weeks of high-frequency rTMS intervention, and the mice in CAA group and control group were only restrained without rTMS intervention.Learning and memory functions were evaluated using the Morris water maze test.Amyloid-beta deposition, glymphatic system clearance, and aquaporin-4(AQP4) polarization were assessed using immunofluorescence, and AQP4 expression levels were measured by Western blot.Statistical analysis of the data was conducted using SPSS 25.0 and GraphPad Prism 9.5 softwares.Repeated-measures ANOVA was used for data on escape latency, and one-way ANOVA was used for comparisons between multiple groups for other data.Results:(1)In the novel object recognition test, there were statistically significant differences in recognition indices among the three groups of mice ( F=22.59, P<0.05). Compared with the control group, the mice in the CAA group showed a significant decrease in the new object recognition index ( P<0.05).Compared with the CAA group, the mice in the rTMS group showed a significant increase in the new object recognition index ( P<0.05).(2)In the Y-maze, there were statistical differences in the spontaneous alternation rates among the three groups ( F=5.00, P<0.05). Compared with the control group, the spontaneous alternation rate in the CAA group was significantly lower ( P<0.05).And compared with the CAA group, the spontaneous alternation rate in the rTMS group was significantly higher ( P<0.05).(3)In the Morris water maze test, there were significant interactions in escape latency among the three groups ( F=4.05, P=0.02), significant main effects of time ( F=713.22, P<0.01), and significant main effects of group ( F=421.55, P<0.01). There was no significant statistical difference in swimming speed among the three groups ( F=0.19, P>0.05), while the difference of the number of entries into the inner zone and the proportion of time spent were statistically significant( F=71.67, 294.14, both P<0.05).Compared with the control group, the CAA group mice significantly decreased in the number of entries into the inner zone and the proportion of time spent in the middle zone (both P<0.01).(4)Compared with the CAA group, the rTMS group significantly increased in the number of entries into the inner zone and the proportion of time spent in the middle zone (both P<0.01).The result of immunofluorescence test showed that there was a statistically significant difference in the levels of Aβ in the cerebral vessels among the three groups( F=385.76, P<0.01).The levels of Aβ in the cerebral vessels of the CAA group (62.00±2.65) were significantly higher than those in the control group (9.00±1.00, P<0.01).The levels in the rTMS group (51.33±3.21) were significantly lower than those in the CAA group (62.00±2.65, P<0.01). Using the residual fluorescence tracer levels of the control group as a baseline, there were statistically significant differences in the tracer intensities in the corpus callosum and cerebral cortex( F=258.97, 46.44, both P<0.05), the tracer intensities in the corpus callosum (3.57±0.21) and cerebral cortex (4.96±0.79) of the CAA group mice were significantly higher than those in the rTMS group (1.45±0.14, 1.78±0.47, P<0.01). The polarization of AQP4 in the cerebral cortex of rTMS group (0.51±0.07) was significantly higher than that in the CAA group (0.30±0.02, P<0.01). Conclusion:rTMS can alleviate learning memory and abnormal Aβ deposition in CAA model mice by modulating AQP4 polarisation and promoting transport function of glymphatic system.

Claudin18.2 is a member of the tight junction protein family,which can be abnormally expressed in a variety of malignant solid tumors,including gastric cancer.The drug therapy targeting Claudin18.2 has been a hot top-ic in recent years,making Claudin18.2 protein detection an important means of screening for tumor therapy.In this re-view,the clinical pathological detection methods,interpretation criteria,and expression research status of Claudin18.2 protein in various malignant solid tumors are reviewed,aiming to provide new ideas for tumor detection and treatment based on Claudin18.2 protein.

Objective:To propose a functional method for locating the shoulder joint center of rotation aimed at rapid estimation of the upper limb reachable domain envelope, thereby informing ergonomic design and task optimization.Methods:In March 2024, shoulder kinematics during gait were recorded from ten adults using a three-dimensional motion-capture system. Assuming the existence of a point near the glenohumeral joint that maintains a fixed spatial relationship to the humerus and the acromion, we estimated both static and dynamic centers of rotation. Localization accuracy was quantified by the standard deviation of distance residuals to upper-arm markers. Upper-limb joint angles and anthropometric parameters were modeled via regression; combined with maximal joint ranges of motion, these were used to infer the reachable domain envelope.Results:The static center of rotation was located approximately twenty-two millimeters medial to the acromial landmark in the coronal plane and thirty-seven millimeters inferior to it. The standard deviation of the residuals for the distances from the dynamic shoulder joint center of rotation to upper-arm markers averaged 1.02 mm, which was 47.42% lower than that of the static center of rotation and 66.56% lower than that of the acromion. Moreover, the trajectory of this dynamic center showed a strong correlation with upper-limb joint angles ( R2>0.7) . Conclusion:The proposed method enables rapid and accurate estimation of the upper limb reachable domain envelope to support ergonomic design and may help reduce the risk of work-related musculoskeletal disorders.

Objective To develop a three-compartment kinetic fatigue model for the isometric muscle endurance of the hip,knee,and ankle joints at 50％IPT(isometric peak torque),so as to provide a theoretical basis for simulation-based assessments and load evaluations in biomechanics and sports science.Methods The IPT of the hip,knee,and ankle joints was measured in 40 male university students.Isometric endurance tests were then performed on all three joints at 50％IPT until exhaustion.Electromyography data and endurance time(ET)of major lower limb muscles were collected concurrently.The differences between ETs predicted by models based on previously recommended F and R parameters and actual ETs were analyzed.Subsequently,experimental ETs were used in a grid search to optimize Fand R parameters,allowing for the development of an accurate three-compartment kinetic model.Results The ET of the hip and ankle joints was significantly longer than that of the knee joint(P＜0.001).Models using previously recommended Fand R parameters overestimated ET,with significantly higher predicted values than experimentally measured ET(P＜0.001),as well as elevated root mean squared error(RMSE)and mean relatvie error(MRE)values.The grid search successfully identified Fand R parameters for the three-compartment model in isometric endurance tests of lower limb joints,with no statistical difference between model-predicted ET and experimental ET(P＞0.05).Conclusions The developed model in this study can serve as an indirect measurement tool for evaluating load in similar activities.

Claudin18.2 is a member of the tight junction protein family,which can be abnormally expressed in a variety of malignant solid tumors,including gastric cancer.The drug therapy targeting Claudin18.2 has been a hot top-ic in recent years,making Claudin18.2 protein detection an important means of screening for tumor therapy.In this re-view,the clinical pathological detection methods,interpretation criteria,and expression research status of Claudin18.2 protein in various malignant solid tumors are reviewed,aiming to provide new ideas for tumor detection and treatment based on Claudin18.2 protein.

BACKGROUND:Surface electromyography has been extensively utilized for monitoring muscle fatigue. However,traditional electromyographic metrics typically focus on individual muscles and fail to assess the variations in a muscle group during the fatigue process. OBJECTIVE:To establish a muscle functional network to extract complex network parameters and investigate the topological property changes of the muscle functional network under different levels of fatigue,aiming to provide theoretical and methodological foundations for fatigue monitoring and prevention. METHODS:Eleven participants performed single-leg leg press exercise at 50％ of one-repetition maximum until exhaustion. Simultaneously,electromyographic signals of seven muscles (rectus femoris,vastus lateralis,vastus medialis,biceps femoris,tibialis anterior,lateral gastrocnemius,and medial gastrocnemius),electrocardiographic signals,and Borg CR-10 scale scores were collected. The Borg CR-10 scale was used to categorize three fatigue stages:mild,moderate,and severe. Heart rate and heart rate variability were calculated to validate the effective division of fatigue stages. Using the coherence of muscle signals,a muscle functional network was constructed with the seven muscles as nodes,and four complex network parameters (clustering coefficient,average weighted degree,global efficiency,and eigenvector centrality) were extracted. Additionally,four electromyographic indices (root mean square,median frequency,instantaneous mean frequency,and co-activation ratio) were extracted and compared under the three levels of fatigue. RESULTS AND CONCLUSION:(1) Differences in heart rate and heart rate variability were observed across three fatigue stages,indicating the effectiveness of fatigue stage delineation. (2) Electromyographic indicators for different muscles under three levels of fatigue:root mean square and co-activation ratio showed no differences;however,median frequency exhibited robust fatigue trends in vastus lateralis,vastus medialis,and biceps femoris,while instantaneous mean frequency demonstrated robust fatigue trends in rectus femoris,vastus lateralis,vastus medialis,and biceps femoris. Instantaneous mean frequency outperformed median frequency and root mean square,yet all three indicators showed robust trends only for the major working muscle groups,unaffected by fatigue factors,unlike the co-activation ratio. (3) The connectivity strength between vastus lateralis and vastus medialis,vastus lateralis and biceps femoris,vastus lateralis and gastrocnemius medialis,and vastus medialis and biceps femoris gradually increased,showing significant differences in average weighted degree,clustering coefficient,and global efficiency post-fatigue,significantly correlated with fatigue levels. To conclude,changes in connectivity strength reflect the synergy and complementarity among muscles during fatigue. Clustering coefficient,average weighted degree,and global efficiency serve as fatigue markers reflecting overall muscle changes.

Objective:To investigate the effects of repetitive transcranial magnetic stimulation(rTMS) on learning memory and abnormal Aβ deposition in cerebral amyloid angiopathy(CAA) model mice, and further to investigate whether the mechanism involves the transport function of glymphatic system.Methods:Eight-month-old SPF grade Tg-SWDI mice were randomly divided into the CAA group and the rTMS group according to the random number table method with 7 in each group.Seven wild-type mice of the same genetic background and age served as the control group. The mice in rTMS group received two weeks of high-frequency rTMS intervention, and the mice in CAA group and control group were only restrained without rTMS intervention.Learning and memory functions were evaluated using the Morris water maze test.Amyloid-beta deposition, glymphatic system clearance, and aquaporin-4(AQP4) polarization were assessed using immunofluorescence, and AQP4 expression levels were measured by Western blot.Statistical analysis of the data was conducted using SPSS 25.0 and GraphPad Prism 9.5 softwares.Repeated-measures ANOVA was used for data on escape latency, and one-way ANOVA was used for comparisons between multiple groups for other data.Results:(1)In the novel object recognition test, there were statistically significant differences in recognition indices among the three groups of mice ( F=22.59, P<0.05). Compared with the control group, the mice in the CAA group showed a significant decrease in the new object recognition index ( P<0.05).Compared with the CAA group, the mice in the rTMS group showed a significant increase in the new object recognition index ( P<0.05).(2)In the Y-maze, there were statistical differences in the spontaneous alternation rates among the three groups ( F=5.00, P<0.05). Compared with the control group, the spontaneous alternation rate in the CAA group was significantly lower ( P<0.05).And compared with the CAA group, the spontaneous alternation rate in the rTMS group was significantly higher ( P<0.05).(3)In the Morris water maze test, there were significant interactions in escape latency among the three groups ( F=4.05, P=0.02), significant main effects of time ( F=713.22, P<0.01), and significant main effects of group ( F=421.55, P<0.01). There was no significant statistical difference in swimming speed among the three groups ( F=0.19, P>0.05), while the difference of the number of entries into the inner zone and the proportion of time spent were statistically significant( F=71.67, 294.14, both P<0.05).Compared with the control group, the CAA group mice significantly decreased in the number of entries into the inner zone and the proportion of time spent in the middle zone (both P<0.01).(4)Compared with the CAA group, the rTMS group significantly increased in the number of entries into the inner zone and the proportion of time spent in the middle zone (both P<0.01).The result of immunofluorescence test showed that there was a statistically significant difference in the levels of Aβ in the cerebral vessels among the three groups( F=385.76, P<0.01).The levels of Aβ in the cerebral vessels of the CAA group (62.00±2.65) were significantly higher than those in the control group (9.00±1.00, P<0.01).The levels in the rTMS group (51.33±3.21) were significantly lower than those in the CAA group (62.00±2.65, P<0.01). Using the residual fluorescence tracer levels of the control group as a baseline, there were statistically significant differences in the tracer intensities in the corpus callosum and cerebral cortex( F=258.97, 46.44, both P<0.05), the tracer intensities in the corpus callosum (3.57±0.21) and cerebral cortex (4.96±0.79) of the CAA group mice were significantly higher than those in the rTMS group (1.45±0.14, 1.78±0.47, P<0.01). The polarization of AQP4 in the cerebral cortex of rTMS group (0.51±0.07) was significantly higher than that in the CAA group (0.30±0.02, P<0.01). Conclusion:rTMS can alleviate learning memory and abnormal Aβ deposition in CAA model mice by modulating AQP4 polarisation and promoting transport function of glymphatic system.

Objective:To propose a functional method for locating the shoulder joint center of rotation aimed at rapid estimation of the upper limb reachable domain envelope, thereby informing ergonomic design and task optimization.Methods:In March 2024, shoulder kinematics during gait were recorded from ten adults using a three-dimensional motion-capture system. Assuming the existence of a point near the glenohumeral joint that maintains a fixed spatial relationship to the humerus and the acromion, we estimated both static and dynamic centers of rotation. Localization accuracy was quantified by the standard deviation of distance residuals to upper-arm markers. Upper-limb joint angles and anthropometric parameters were modeled via regression; combined with maximal joint ranges of motion, these were used to infer the reachable domain envelope.Results:The static center of rotation was located approximately twenty-two millimeters medial to the acromial landmark in the coronal plane and thirty-seven millimeters inferior to it. The standard deviation of the residuals for the distances from the dynamic shoulder joint center of rotation to upper-arm markers averaged 1.02 mm, which was 47.42% lower than that of the static center of rotation and 66.56% lower than that of the acromion. Moreover, the trajectory of this dynamic center showed a strong correlation with upper-limb joint angles ( R2>0.7) . Conclusion:The proposed method enables rapid and accurate estimation of the upper limb reachable domain envelope to support ergonomic design and may help reduce the risk of work-related musculoskeletal disorders.