Objective:To evaluate the long-term efficacy of second-course radiotherapy for patients with locally recurrent rectal cancer (LRRC) following pelvic radiotherapy.Methods:Data of 34 patients with in-field pelvic recurrence of rectal cancer that could not be resected with R0 surgery admitted to Peking University Third Hospital from October 2012 to April 2024 were retrospectively analyzed. All patients received second-course intensity-modulated radiotherapy and the median radiation dose for the first course was 50 Gy (range 45-66 Gy), and for the second course, the median dose was 45 Gy (range 10-60.4 Gy). Regular follow-up visits and imaging examination were performed during follow-up. The recurrence of all patients was analyzed. According to the site of recurrence, all patients were divided into the presacral, pelvic wall and central recurrence groups. Local recurrence-free survival (LRFS) and overall survival (OS) rates were estimated using the Kaplan-Meier method. The survival among groups was compared by two-sided log-rank test.Results:The median follow-up period was 22 months. Among 34 patients, recurrence was observed in 38 sites, primarily at the central region (24 sites, 63%) and 23 patients (68%) had initial recurrence. The median OS was 47 months, and the median LRFS was 19 months. The 1-, 2-, 3- and 5-year OS rates were 93.1%, 75.3%, 69.1% and 38.4%, respectively. The 1- and 2-year LRFS rates were 69.8% and 27.2%. There were no significant differences in OS among the presacral, pelvic wall and central recurrence groups ( P=0.616). Conclusions:For patients with locally recurrent rectal cancer that cannot be resected with R0 margins, second-course radiotherapy offers higher clinical efficacy compared with alternative therapeutic options previously reported.

Aim To observe the mechanism of salvian-olic acid B(SalB)against oxygen glucose deprivation/re-oxygenation(OGD/R)injury in H9c2 cardiomyo-cytes.Methods The protective concentration of SalB against OGD/R-injured H9c2 cardiomyocytes was screened by CCK-8 assay.The levels of lactate dehy-drogenase(LDH),aspartate transaminase(AST)and creatine kinase(CK)were detected by ELISA kit.The mechanism of action of SalB on OGD/R-injured H9c2 cardiomyocytes was explored using high-through-put sequencing of the transcriptome.The binding of SalB to differential proteins was assessed using molecu-lar docking assays.Fatty acid content was determined using free fatty acid kits.The relative expressions of mRNA and protein of differential genes were verified by RT-qPCR and Western blot.The causal relationship between the target of action of SalB and heart failure was examined by Mendelian randomization experiment.Results SalB protected OGD/R-injured H9c2 cardio-myocytes and significantly reduced the levels of CK,LDH and AST compared with the blank control group.One hundred differential genes were screened by tran-scriptome sequencing,which were mainly involved in fatty acid elongation,central carbon metabolism of cancer,tryptophan metabolism pathways.Molecular docking showed that SalB had good binding energy to differential proteins.The mRNA and protein expression of core differential genes Elovl6,Echs1 and Acot1 were consistent with the transcriptome sequencing results.SalB reduced fatty acidsafter OGD/R injury.Mende-lian randomization experiments suggested that SalB might reduce the risk of heart failure through fatty acid metabolism,thereby reducing the risk of heart failure.Conclusion SalB can protect H9c2 cardiomyocytes after OGD/R injury by down-regulating Elovl6,Echs1 and Acot1 expression through the fatty acid metabolism pathway.

Objective To analyze the biomechanical characteristics of cannulated screws internal fixation models with different spatial distribution in the treatment of PauwelsⅡ fracture of the femoral neck through finite element analysis.Methods One healthy male volunteer was selected as the research subject.A thin-layer scan from the femoral head to the distal femur of the volunteer was performed using 128-slice spiral CT to preliminarily construct a three-dimensional mesh model of the femur.Through subsequent processing,a cannulated screw internal fixation model conforming to human anatomical characteristics was obtained.A horizontal line was drawn based on the center line of the femoral shaft,and the fracture line was set at the center of the femoral neck with an angle of 50° to the horizontal line to construct the Pauwels Ⅱ femoral neck fracture model.Five kinds of cannulated screw internal fixation models with different spatial distribution were simulated and designed in SolidWorks 2021 software,and the assembly models were imported into Ansys 2021R1 software to establish the finite element model.The stress distribution of the femur and its internal fixator in the five models were evaluated,and the displacement of the femoral neck fracture cross-section in the X,Y,and Z directions,as well as the overall displacement of the femur and the internal fixator were analyzed.Results The stresses of the proximal femur of the five models concentrated below the femoral neck fracture line,and the stress peak of the inverted equilateral triangle configuration was the smallest(19.179 MPa).The total stresses of the internal fixator in the five models all concentrated in the middle region of the ventral cannulated screw at the proximal femur,and the stress peak of the inverted equilateral triangle configuration was the lowest(61.742 MPa).The maximum displacement of the femoral neck fracture cross-section in the X and Y directions of the five models all appeared in the anterior and upper regions of the cross-section,and the displacement of the inverted equilateral triangle configuration was the smallest(X axis:0.446 54 mm,Y axis:0.704 21 mm).The maximum displacement of the femoral neck fracture cross-section in the Z direction of the five models all occurred in the posterior upper part of the cross-section,among which the displacement of the inverted equilateral triangle configuration was the smallest(0.225 62 mm).The overall displacement of the proximal femur of the five models concentrated in the stress-loading area of the femoral head,and the displacement of the inverted equilateral triangle configuration was the smallest(0.721 16 mm).The maximum displacement of the internal fixator of the five models located at the tip of the cannulated screw fixed at the top of the femoral neck near the posterior wall,and the displacement of the inverted equilateral triangle configuration was the smallest(0.686 83 mm).Conclusion Among the five different cannulated screws internal fixation models for Pauwels Ⅱ femoral neck fractures,the inverted equilateral triangle configuration has the best stress dispersion effect,the smallest displacement of fracture end,and the best biomechanical stability.

Aim To observe the mechanism of salvian-olic acid B(SalB)against oxygen glucose deprivation/re-oxygenation(OGD/R)injury in H9c2 cardiomyo-cytes.Methods The protective concentration of SalB against OGD/R-injured H9c2 cardiomyocytes was screened by CCK-8 assay.The levels of lactate dehy-drogenase(LDH),aspartate transaminase(AST)and creatine kinase(CK)were detected by ELISA kit.The mechanism of action of SalB on OGD/R-injured H9c2 cardiomyocytes was explored using high-through-put sequencing of the transcriptome.The binding of SalB to differential proteins was assessed using molecu-lar docking assays.Fatty acid content was determined using free fatty acid kits.The relative expressions of mRNA and protein of differential genes were verified by RT-qPCR and Western blot.The causal relationship between the target of action of SalB and heart failure was examined by Mendelian randomization experiment.Results SalB protected OGD/R-injured H9c2 cardio-myocytes and significantly reduced the levels of CK,LDH and AST compared with the blank control group.One hundred differential genes were screened by tran-scriptome sequencing,which were mainly involved in fatty acid elongation,central carbon metabolism of cancer,tryptophan metabolism pathways.Molecular docking showed that SalB had good binding energy to differential proteins.The mRNA and protein expression of core differential genes Elovl6,Echs1 and Acot1 were consistent with the transcriptome sequencing results.SalB reduced fatty acidsafter OGD/R injury.Mende-lian randomization experiments suggested that SalB might reduce the risk of heart failure through fatty acid metabolism,thereby reducing the risk of heart failure.Conclusion SalB can protect H9c2 cardiomyocytes after OGD/R injury by down-regulating Elovl6,Echs1 and Acot1 expression through the fatty acid metabolism pathway.

Objective To analyze the biomechanical characteristics of cannulated screws internal fixation models with different spatial distribution in the treatment of PauwelsⅡ fracture of the femoral neck through finite element analysis.Methods One healthy male volunteer was selected as the research subject.A thin-layer scan from the femoral head to the distal femur of the volunteer was performed using 128-slice spiral CT to preliminarily construct a three-dimensional mesh model of the femur.Through subsequent processing,a cannulated screw internal fixation model conforming to human anatomical characteristics was obtained.A horizontal line was drawn based on the center line of the femoral shaft,and the fracture line was set at the center of the femoral neck with an angle of 50° to the horizontal line to construct the Pauwels Ⅱ femoral neck fracture model.Five kinds of cannulated screw internal fixation models with different spatial distribution were simulated and designed in SolidWorks 2021 software,and the assembly models were imported into Ansys 2021R1 software to establish the finite element model.The stress distribution of the femur and its internal fixator in the five models were evaluated,and the displacement of the femoral neck fracture cross-section in the X,Y,and Z directions,as well as the overall displacement of the femur and the internal fixator were analyzed.Results The stresses of the proximal femur of the five models concentrated below the femoral neck fracture line,and the stress peak of the inverted equilateral triangle configuration was the smallest(19.179 MPa).The total stresses of the internal fixator in the five models all concentrated in the middle region of the ventral cannulated screw at the proximal femur,and the stress peak of the inverted equilateral triangle configuration was the lowest(61.742 MPa).The maximum displacement of the femoral neck fracture cross-section in the X and Y directions of the five models all appeared in the anterior and upper regions of the cross-section,and the displacement of the inverted equilateral triangle configuration was the smallest(X axis:0.446 54 mm,Y axis:0.704 21 mm).The maximum displacement of the femoral neck fracture cross-section in the Z direction of the five models all occurred in the posterior upper part of the cross-section,among which the displacement of the inverted equilateral triangle configuration was the smallest(0.225 62 mm).The overall displacement of the proximal femur of the five models concentrated in the stress-loading area of the femoral head,and the displacement of the inverted equilateral triangle configuration was the smallest(0.721 16 mm).The maximum displacement of the internal fixator of the five models located at the tip of the cannulated screw fixed at the top of the femoral neck near the posterior wall,and the displacement of the inverted equilateral triangle configuration was the smallest(0.686 83 mm).Conclusion Among the five different cannulated screws internal fixation models for Pauwels Ⅱ femoral neck fractures,the inverted equilateral triangle configuration has the best stress dispersion effect,the smallest displacement of fracture end,and the best biomechanical stability.

Objective:To evaluate the long-term efficacy of second-course radiotherapy for patients with locally recurrent rectal cancer (LRRC) following pelvic radiotherapy.Methods:Data of 34 patients with in-field pelvic recurrence of rectal cancer that could not be resected with R0 surgery admitted to Peking University Third Hospital from October 2012 to April 2024 were retrospectively analyzed. All patients received second-course intensity-modulated radiotherapy and the median radiation dose for the first course was 50 Gy (range 45-66 Gy), and for the second course, the median dose was 45 Gy (range 10-60.4 Gy). Regular follow-up visits and imaging examination were performed during follow-up. The recurrence of all patients was analyzed. According to the site of recurrence, all patients were divided into the presacral, pelvic wall and central recurrence groups. Local recurrence-free survival (LRFS) and overall survival (OS) rates were estimated using the Kaplan-Meier method. The survival among groups was compared by two-sided log-rank test.Results:The median follow-up period was 22 months. Among 34 patients, recurrence was observed in 38 sites, primarily at the central region (24 sites, 63%) and 23 patients (68%) had initial recurrence. The median OS was 47 months, and the median LRFS was 19 months. The 1-, 2-, 3- and 5-year OS rates were 93.1%, 75.3%, 69.1% and 38.4%, respectively. The 1- and 2-year LRFS rates were 69.8% and 27.2%. There were no significant differences in OS among the presacral, pelvic wall and central recurrence groups ( P=0.616). Conclusions:For patients with locally recurrent rectal cancer that cannot be resected with R0 margins, second-course radiotherapy offers higher clinical efficacy compared with alternative therapeutic options previously reported.

Manganese superoxide dismutase catalyzes the dismutation of two molecules of superoxide radicals to one molecule of oxygen and one molecule of hydrogen peroxide. The oxidation of superoxide anion to oxygen by Mn³⁺SOD proceeds at a rate close to diffusion. The reduction of superoxide anion to hydrogen peroxide by Mn²⁺SOD can be progressed parallelly in either a fast or a slow cycle pathway. In the slow cycle pathway, Mn²⁺SOD forms a product inhibitory complex with superoxide anion, which is protonated and then slowly releases hydrogen peroxide out. In the fast cycle pathway, superoxide anion is directly converted into product hydrogen peroxide by Mn²⁺SOD, which facilitates the revival and turnover of the enzyme. We proposed for the first time that temperature is a key factor that regulates MnSOD into the slow- or fast-cycle catalytic pathway. Normally, the Mn²⁺ rest in the pent-coordinated state with four amino acid residues (His26, His74, His163 and Asp159) and one water (WAT1) in the active center of MnSOD. The sixth coordinate position on Mn (orange arrow) is open for water (WAT2, green) or O₂^• to coordinate. With the cold contraction in the active site as temperature decreases, WAT2 is closer to Mn, which may spatially interfere with the entrance of O₂^• into the inner sphere, and avoid O₂^•/Mn²⁺ coordination to reduce product inhibition. Low temperature compels the reaction into the faster outer sphere pathway, resulting in a higher gating ratio for the fast-cycle pathway. As the temperature increases in the physiological temperature range, the slow cycle becomes the mainstream of the whole catalytic reaction, so the increasing temperature in the physiological range inhibits the activity of the enzyme. The biphasic enzymatic kinetic properties of manganese superoxide dismutase can be rationalized by a temperature-dependent coordination model of the conserved active center of the enzyme. When the temperature decreases, a water molecule (or OH^-) is close to or even coordinates Mn, which can interfere with the formation of product inhibition. So, the enzymatic reaction occurs mainly in the fast cycle pathway at a lower temperature. Finally, we describe the several chemical modifications of the enzyme, indicating that manganese superoxide dismutase can be rapidly regulated in many patterns (allosteric regulation and chemical modification). These regulatory modulations can rapidly and directly change the activation of the enzyme, and then regulate the balance and fluxes of superoxide anion and hydrogen peroxide in cells. We try to provide a new theory to reveal the physiological role of manganese superoxide dismutase and reactive oxygen species.

Objective To explore early postoperative gait characteristics and clinical outcomes after total knee arthroplasty(TKA).Methods From February 2023 to July 2023,26 patients with unilateral knee osteoarthritis(KOA)were treated with TKA,including 4 males and 22 females,aged from 57 to 85 years old with an average of(67.58±6.49)years old;body mass in-dex(BMI)ranged from 18.83 to 38.28 kg·m-2 with an average of(26.43±4.15)kg·m-2;14 patients on the left side,12 pa-tients on the right side;according to Kellgren-Lawrence(K-L)classification,6 patients with grade Ⅲ and 20 patients with grade Ⅳ;the courses of disease ranged from 1 to 14 years with an average of(5.54±3.29)years.Images and videos of standing up and walking,walking side shot,squatting and supine kneeling were taken with smart phones before operation and 6 weeks after operation.The human posture estimation framework OpenPose were used to analyze stride frequency,step length,step length,step speed,active knee knee bending angle,stride length,double support phase time,as well as maximum hip flexion angle and maximum knee bending angle on squatting position.Western Ontario and McMaster Universities(WOMAC)arthritis index and Knee Society Score(KSS)were used to evaluate clinical efficacy of knee joint.Results All patients were followed up for 5 to 7 weeks with an average of(6.00±0.57)weeks.The total score of WOMAC decreased from(64.85±11.54)before op-eration to(45.81±7.91)at 6 weeks after operation(P＜0.001).The total KSS was increased from(101.19±9.58)before opera-tion to(125.50±10.32)at 6 weeks after operation(P＜0.001).The gait speed,stride frequency and stride length of the affected side before operation were(0.32±0.10)m·s-1,(96.35±24.18)steps·min-1,(0.72±0.14)m,respectively;and increased to(0.48±0.11)m·s 1,(104.20±22.53)steps·min-1,(0.79±0.10)m at 6 weeks after operation(P＜0.05).The lower limb support time and active knee bending angle decreased from(0.31±0.38)sand(125.21±11.64)° before operation to(0.11±0.04)s and(120.01±13.35)° at 6 weeks after operation(P＜0.05).Eleven patients could able to complete squat before operation,13 patients could able to complete at 6 weeks after operation,and 9 patients could able to complete both before operation and 6 weeks after operation.In 9 patients,the maximum bending angle of crouching position was increased from 76.29° to 124.11° before operation to 91.35° to 134.12° at 6 weeks after operation,and the maximum bending angle of hip was increased from 103.70° to 147.25° before operation to 118.61° to 149.48° at 6 weeks after operation.Conclusion Gait analysis technology based on artificial intelligence image recognition is a safe and effective method to quantitatively identify the changes of pa-tients'gait.Knee pain of KOA was relieved and the function was improved,the supporting ability of the affected limb was im-proved after TKA,and the patient's stride frequency,stride length and stride speed were improved,and the overall movement rhythm of both lower limbs are more coordinated.

This study explores the effect of total flavonoids of Rhododendra simsii(TFR) on middle cerebral artery occlusion(MCAO)-induced cerebral injury in rats and oxygen-glucose deprivation/reoxygenation(OGD/R) injury in PC12 cells and the underlying mechanism. The MCAO method was used to induce focal ischemic cerebral injury in rats. Male SD rats were randomized into sham group, model group, and TFR group. After MCAO, TFR(60 mg·kg~(-1)) was administered for 3 days. The content of tumor necrosis factor-α(TNF-α), interleukin-1(IL-1), and interleukin-6(IL-6) in serum was detected by enzyme-linked immunosorbent assay(ELISA). The pathological changes of brain tissue and cerebral infarction were observed based on hematoxylin and eosin(HE) staining and 2,3,5-triphenyltetrazolium chloride(TTC) staining. RT-qPCR and Western blot were used to detect the mRNA and protein levels of calcium release-activated calcium channel modulator 1(ORAI1), stromal interaction molecule 1(STIM1), stromal intera-ction molecule 2(STIM2), protein kinase B(PKB), and cysteinyl aspartate specific proteinase 3(caspase-3) in brain tissues. The OGD/R method was employed to induce injury in PC12 cells. Cells were randomized into the normal group, model group, gene silencing group, TFR(30 μg·mL~(-1)) group, and TFR(30 μg·mL~(-1))+gene overexpression plasmid group. Intracellular Ca~(2+) concentration and apoptosis rate of PC12 cells were measured by laser scanning confocal microscopy and flow cytometry. The effect of STIM-ORAI-regulated store-operated calcium entry(SOCE) pathway on TFR was explored based on gene silencing and gene overexpression techniques. The results showed that TFR significantly alleviated the histopathological damage of brains in MCAO rats after 3 days of admini-stration, reduced the contents of TNF-α, IL-1, and IL-6 in the serum, down-regulated the expression of ORAI1, STIM1, STIM2, and caspase-3 genes, and up-regulated the expression of PKB gene in brain tissues of MCAO rats. TFR significantly decreased OGD/R induced Ca~(2+) overload and apoptosis in PC12 cells. However, it induced TFR-like effect by ORAI1, STIM1 and STIM2 genes silencing. However, overexpression of these genes significantly blocked the effect of TFR in reducing Ca~(2+) overload and apoptosis in PC12 cells. In summary, in the early stage of focal cerebral ischemia-reperfusion injury and OGD/R-induced injury in PC12 cells TFR attenuates ischemic brain injury by inhibiting the STIM-ORAI-regulated SOCE pathway and reducing Ca~(2+) overload and inflammatory factor expression, and apoptosis.
Animals ; Male ; Rats ; Apoptosis ; Brain Ischemia/metabolism* ; Caspase 3 ; Interleukin-1 ; Interleukin-6 ; Rats, Sprague-Dawley ; Reperfusion Injury/metabolism* ; Tumor Necrosis Factor-alpha/genetics* ; Flavonoids/pharmacology* ; Rhododendron/chemistry*