Objective To explore the effect of exercise-induced fatigue on intra-and interhemispher-ic functional connectivity of the primary motor cortex during unilateral ankle plantar-dorsiflexion.Meth-ods Twenty-four healthy adult males(age:21.6±2.2 years;all right-side dominant)were selected as participants for the study.They ran on a treadmill at an individualized constant speed until fatigue.Fatigue was determined when all the following criteria were met:(1)participants failing to maintain the individualized constant speed despite the strong verbal encouragement from the experimenters;(2)reaching a rating of perceived exertion(RPE)score of at least 19;and(3)their heart rate reaching 90%of their age-predicted maximal heart rate(220-age).Moreover,EEG signals from four channels(C1,C2,C3,and C4)of the primary motor cortex were collected during unilateral ankle dorsi-plan-tarflexion movements before and after fatigue,followed by EEG coherence analyses on the collected da-ta.Results Compared to the pre-fatigue state,the coherence values of the intra-hemispheric primary motor cortex electrode pairs C1-C3 and C2-C4 during unilateral ankle plantar-dorsiflexion decreased significantly in the alpha and gamma bands after fatigue(both P<0.05).Conversely,the value of the interhemispheric primary motor cortex electrode pair C1-C2 increased significantly in the beta band(P<0.05).Conclusion Exercise-induced fatigue significantly weakens the intra-hemispheric functional con-nectivity of the primary motor cortex during unilateral ankle plantar-dorsiflexion.However,it may en-hance the interhemispheric functional connectivity and potentially collaborate to strengthen the regula-tion of fatigued muscles.

Objective To explore the effect of exercise-induced fatigue on intra-and interhemispher-ic functional connectivity of the primary motor cortex during unilateral ankle plantar-dorsiflexion.Meth-ods Twenty-four healthy adult males(age:21.6±2.2 years;all right-side dominant)were selected as participants for the study.They ran on a treadmill at an individualized constant speed until fatigue.Fatigue was determined when all the following criteria were met:(1)participants failing to maintain the individualized constant speed despite the strong verbal encouragement from the experimenters;(2)reaching a rating of perceived exertion(RPE)score of at least 19;and(3)their heart rate reaching 90%of their age-predicted maximal heart rate(220-age).Moreover,EEG signals from four channels(C1,C2,C3,and C4)of the primary motor cortex were collected during unilateral ankle dorsi-plan-tarflexion movements before and after fatigue,followed by EEG coherence analyses on the collected da-ta.Results Compared to the pre-fatigue state,the coherence values of the intra-hemispheric primary motor cortex electrode pairs C1-C3 and C2-C4 during unilateral ankle plantar-dorsiflexion decreased significantly in the alpha and gamma bands after fatigue(both P<0.05).Conversely,the value of the interhemispheric primary motor cortex electrode pair C1-C2 increased significantly in the beta band(P<0.05).Conclusion Exercise-induced fatigue significantly weakens the intra-hemispheric functional con-nectivity of the primary motor cortex during unilateral ankle plantar-dorsiflexion.However,it may en-hance the interhemispheric functional connectivity and potentially collaborate to strengthen the regula-tion of fatigued muscles.

BACKGROUND:The incidence of inflammatory bowel disease has been steadily rising,accompanied by a lack of definitive therapeutic strategies.Recent research endeavors have illuminated the promising potential of mesenchymal stem cells in mitigating the symptoms of inflammatory bowel disease,offering a glimmer of hope for afflicted patients.OBJECTIVE:To review the mechanisms of action of mesenchymal stem cells derived from various sources in the management of inflammatory bowel disease,aiming to provide insights for future research endeavors.METHODS:Utilizing the keywords"mesenchymal stem cells,MSCs,exosomes,extracellular vesicles,EVs,inflammatory bowel disease,IBD,ulcerative colitis,UC,Crohn's disease,CD"in English and their Chinese equivalents in CNKI and PubMed databases,a total of 89 eligible articles were selected for this review.RESULTS AND CONCLUSION:Currently,six types of mesenchymal stem cells are being explored for inflammatory bowel disease therapy:bone marrow-derived mesenchymal stem cells,adipose tissue-derived mesenchymal stem cells,perinatal tissue-derived mesenchymal stem cells,induced pluripotent stem cell-derived mesenchymal stem cells,embryonic stem cell-derived mesenchymal stem cells,and gingival mesenchymal stem cells.Five administration routes have been adopted,with intravenous and intraperitoneal injections being the most prevalent,followed by local,mesenteric,and intra rectal injections.Their therapeutic mechanisms encompass differentiation,regeneration,anti-inflammatory effects,immune modulation,neuroprotection,antioxidant stress response,homing,modulation of gut microbiota,autophagy,ferroptosis,and endoplasmic reticulum stress.While sharing functional similarities,mesenchymal stem cells from different sources exhibit unique characteristics that confer them with distinct advantages and therapeutic potentials.Nevertheless,research into the specific properties of these mesenchymal stem cells remains limited,necessitating deeper exploration of their nuanced differences to optimize their therapeutic efficacy in inflammatory bowel disease.Additionally,the clinical safety of mesenchymal stem cells-based therapies warrants further observation and evaluation.

The triceps surae muscle-tendon unit(MTU)is the key for effective force generation,transmission,and energy storage and release in human movement,with great influences on sports efficiency,but its injury rate remains high.This review summarizes MTU function and its biomechanical adaptations during running,aiming to deepen the understanding of MTU's role in movement and explore how external factors influence its biomechanical properties,offering scientific insights for improving running performance and preventing injuries.During running,under forefoot striking and wearing shoes with greater stiffness,such as shoes with carbon plate,the energy contraction or return could be achieved through a more economical MTU behavior,namely reducing energy consumption by more economically muscle contraction and more energy storage of elastic elements,and the muscle contraction was exerted at a length closer to the optimal muscle fascicle length and reduced energy consumption caused by muscle contraction.However,adopting forefoot striking,barefoot running,or wearing minimalist shoes during running could increase the mechanical loads on the MTU.After gait retraining,the MTU could contract or return energy more efficiently during running,while the impact of other training methods on MTU was relatively poor,and the research in this area is still not sufficient.Therefore,future research should focus on optimizing the biomechanical properties of the MTU,MTU interaction and balanced development through changes in movement patterns,equipment,and training methods to enhance performance and reduce injuries.

The triceps surae muscle-tendon unit(MTU)is the key for effective force generation,transmission,and energy storage and release in human movement,with great influences on sports efficiency,but its injury rate remains high.This review summarizes MTU function and its biomechanical adaptations during running,aiming to deepen the understanding of MTU's role in movement and explore how external factors influence its biomechanical properties,offering scientific insights for improving running performance and preventing injuries.During running,under forefoot striking and wearing shoes with greater stiffness,such as shoes with carbon plate,the energy contraction or return could be achieved through a more economical MTU behavior,namely reducing energy consumption by more economically muscle contraction and more energy storage of elastic elements,and the muscle contraction was exerted at a length closer to the optimal muscle fascicle length and reduced energy consumption caused by muscle contraction.However,adopting forefoot striking,barefoot running,or wearing minimalist shoes during running could increase the mechanical loads on the MTU.After gait retraining,the MTU could contract or return energy more efficiently during running,while the impact of other training methods on MTU was relatively poor,and the research in this area is still not sufficient.Therefore,future research should focus on optimizing the biomechanical properties of the MTU,MTU interaction and balanced development through changes in movement patterns,equipment,and training methods to enhance performance and reduce injuries.

BACKGROUND:The incidence of inflammatory bowel disease has been steadily rising,accompanied by a lack of definitive therapeutic strategies.Recent research endeavors have illuminated the promising potential of mesenchymal stem cells in mitigating the symptoms of inflammatory bowel disease,offering a glimmer of hope for afflicted patients.OBJECTIVE:To review the mechanisms of action of mesenchymal stem cells derived from various sources in the management of inflammatory bowel disease,aiming to provide insights for future research endeavors.METHODS:Utilizing the keywords"mesenchymal stem cells,MSCs,exosomes,extracellular vesicles,EVs,inflammatory bowel disease,IBD,ulcerative colitis,UC,Crohn's disease,CD"in English and their Chinese equivalents in CNKI and PubMed databases,a total of 89 eligible articles were selected for this review.RESULTS AND CONCLUSION:Currently,six types of mesenchymal stem cells are being explored for inflammatory bowel disease therapy:bone marrow-derived mesenchymal stem cells,adipose tissue-derived mesenchymal stem cells,perinatal tissue-derived mesenchymal stem cells,induced pluripotent stem cell-derived mesenchymal stem cells,embryonic stem cell-derived mesenchymal stem cells,and gingival mesenchymal stem cells.Five administration routes have been adopted,with intravenous and intraperitoneal injections being the most prevalent,followed by local,mesenteric,and intra rectal injections.Their therapeutic mechanisms encompass differentiation,regeneration,anti-inflammatory effects,immune modulation,neuroprotection,antioxidant stress response,homing,modulation of gut microbiota,autophagy,ferroptosis,and endoplasmic reticulum stress.While sharing functional similarities,mesenchymal stem cells from different sources exhibit unique characteristics that confer them with distinct advantages and therapeutic potentials.Nevertheless,research into the specific properties of these mesenchymal stem cells remains limited,necessitating deeper exploration of their nuanced differences to optimize their therapeutic efficacy in inflammatory bowel disease.Additionally,the clinical safety of mesenchymal stem cells-based therapies warrants further observation and evaluation.

Objective To investigate the effects of different foot strike patterns during running on Achilles tendon(AT)morphology and mechanical loading.Methods Fourteen habitual rearfoot strike runners and 14 habitual forefoot strike runners were recruited.Morphological characteristics(tendon length,cross-sectional area,and thickness)of the AT were collected using ultrasound imaging.The AT loading characteristics(plantar flexion moment,tendon force,load rate,impulse,and stress)of subjects wearing cushioned running shoes while running at a speed of 10 km/h were collected and calculated using a three-dimensional force measurement treadmill.Results Compared to habitual rearfoot strike runners,habitual forefoot strike runners showed a significant increase in peak plantar flexion moment of ankle joint,AT peak force,average loading rate,and peak loading rate(P<0.05).However,the differences in AT length,cross-sectional area,and thickness between the two groups were not statistically significant(P>0.05).Conclusions Long-term forefoot strike patterns can adaptively enhance the mechanical loading characteristics of the AT during repetitive stretch-shortening cycles.

Objective To analyze the risk factors of venous thromboembolism(VTE)after endoscopic surgery in elderly patients with urinary system calculi,construct a prediction model and validate it.Methods A retrospective analysis was conducted on the clinical data of 402 elderly patients(≥ 60 years)with urinary system calculi who underwent endoscopic surgery in our hospital during Jan.2018 and Jan.2023.The patients were divided into VTE group(n=43)and non-VTE group(n=359)based on whether VTE occurred after surgery.Risk factors of VTE were screened with univariate and multivariate logistic regression analyses.Based on the screening results(P＜0.05 for the factor),a nomogram prediction model was established,the receiver operating characteristic(ROC)curve was drawn,the area under the curve(AUC)was calculated to determine the efficacy of the model,and a calibration chart was drawn to determine the accuracy of the model.Results Univariate analysis showed that age＞70 years,body mass index(BMI)≥30,VTE history,history of malignant tumors,diabetes,operation time＞180 min,diuretic use during operation,and postoperative ambulation time＞24 h were risk factors of VTE(P＜0.05).Logistic regression analysis showed that age＞70 years,BMI ≥ 30,history of VTE,history of malignant tumors,and operation time＞180 min were independent risk factors of VTE(P＜0.05).The AUC in the ROC curve of the validation set data was 0.789(95％CI:0.731-0.848,P＜0.001).The calibration chart showed that the calibration curve was close to the standard curve(Brier=0.13).Conclusion Age＞70 years,BMI ≥30,history of VTE,history of malignant tumors,and surgery time＞180 min are independent risk factors of postoperative VTE in elderly patients with urinary system calculi undergoing endoscopic surgery.The prediction model can effectively predict the risk factors of postoperative VTE.

Methods: This retrospective analysis included a total of 155 patients who underwent single-level lumbar fusion, with 81 patients in the traditional group and 74 patients in the Wiltse group (less paraspinal muscle damage). QCT was used to measure the volumetric BMD (vBMD), Hounsfield unit value, and cross-sectional area of the paraspinal muscles at the upper instrumented vertebrae (UIV), vertebrae one segment above the UIV (UIV+1), and the vertebrae one segment above the UIV+1 (UIV+2). Statistical analyses were performed. Results: No significant differences in general data were observed between the two groups (p>0.05). Strong correlations were noted between the preoperative and 1-week postoperative vBMD of each segment (p<0.01), with no significant difference between the two time points in both groups (p>0.05). Vertebral BMD loss was significantly higher in UIV+1 and UIV+2 in the traditional group than in the Wiltse group (−13.6%±19.1% vs. −4.2%±16.5%, −10.8%±20.3% vs. −0.9%±37.0%; p<0.05). However, no statistically significant difference was observed in the percent vBMD changes in the UIV segment between the two groups (37.7%±70.1% vs. 36.1%±78.7%, p>0.05). Conclusions QCT can reliably determine BMD in the instrumented spine after lumbar interbody fusion. With QCT, we found that reducing paraspinal muscle destruction through the Wiltse approach during surgery can help preserve the adjacent vertebral BMD; however, it does not help increase the BMD in the instrumented vertebrae.

Objective To investigate the correlation of vertebral bone quality(VBQ)and paraspinal muscle changes with adjacent segment degeneration(ASD)after transforaminal lumbar interbody fusion(TLIF)through a retrospective analysis of patients who have undergone TLIF for lumbar degenerative diseases(LDD).Methods A total of 98 patients who underwent TLIF surgical treatment for LDD between January 2016 and December 2022 at Shenzhen People's Hospital were selected.Well-established follow-up imaging data were available for all subjects who were divided into two groups,the ASD group(n=43)and the non-ASD(N-ASD)group(n=55),according to whether they met the ASD evaluation criteria.Data on the basic characteristics of the patients in both groups were collected,and the relevant parameters,including VBQ and the total cross-sectional area(TCSA)and the functional cross-sectional area(FCSA)of psoas major(PM),erector spinae(ES),and multifidus(MF),were measured by magnetic resonance imaging of the lumbar spine performed preoperatively and at the last follow-up.Then,the relative fat infiltration(RFI)was calculated from the above metrics accordingly.Logistic regression analysis was conducted to investigate the risk factors for ASD.Results The incidence of ASD was 43.9％(n=43)at the final follow-up.The mean follow-up time was(27.23±4.15)months.The age,body mass index(BMI),preoperative bone mineral density(BMD),preoperative VBQ,△RFIPM,and△RFIES+MF showed significant differences between the ASD and N-ASD groups(P＜0.05).According to the results of the logistic regression analysis,BMI(odds ratio[OR]=1.450,95％confidence interval[CI]:1.081-1.945,P=0.013),preoperative VBQ(OR=6.191,95％CI:1.692-22.657,P=0.006),and △RFIES+MF(OR=1.117,95％CI:1.007-1.238,P=0.037)were independent risk factors for ASD.Conclusion The incidence of postoperative ASD in patients who have undergone TLIF for LDD was found to be associated with higher BMI,preoperative VBQ,and increased postoperative relative fat infiltration of the ES and MF muscles.Consequently,it is advisable to prioritize the intraoperative protection of the paraspinal muscles during TLIF.In the postoperative period,it is essential to strengthen exercises of the lower back muscles and to optimize bone mass and weight management,which is conducive to reducing the risk of ASD in the postoperative period.