BACKGROUND:Upper lumbar spinal stenosis is a multifactorial degenerative disorder of the spine.For narrowing of the spinal canal in the upper lumbar region(L1-L4),surgical decision-making is particularly complex.Existing minimally invasive surgeries each have their own advantages and limitations.Currently,there are few reports on biomechanical comparison and finite element analysis of different surgical methods for the treatment of high lumbar spinal stenosis.OBJECTIVE:To analyze the biomechanical impact of endoscopic unilateral laminotomy for bilateral decompression,transforaminal endoscopic lumbar decompression,and cross-overtop decompression in the treatment of upper lumbar spinal stenosis using endoscopy,and to verify the reliability and effectiveness of these three surgical techniques in treating upper lumbar spinal stenosis,providing a biomechanical basis for clinical decision-making.METHODS:The CT images of the lumbar spine of a healthy volunteer were selected,and the finite element model M0 of the normal lumbar L1-L5 segments was established using Mimics,Geomagic,Solid works,and Ansys software.The L2-L3 segment,representing upper lumbar characteristics,was chosen.Based on this model,the surgical models for endoscopic unilateral laminotomy for bilateral decompression(M1),transforaminal endoscopic lumbar decompression(M2),and cross-overtop decompression(M3)were established.Using software,the changes in the range of motion of the entire lumbar segment and the maximum Von Mises stress of the intervertebral discs were simulated and evaluated for each group of models under six loading conditions:flexion,extension,left lateral bending,right lateral bending,left rotation,and right rotation.RESULTS AND CONCLUSION:(1)Compared with model MO,the range of motion in M1,M2,and M3 increased under all six conditions,with M1 showing a greater increase.(2)M1 and M2 demonstrated significant increases in range of motion under forward bending,extension,and right rotation,while the increase under other conditions remained below 7％.(3)Compared with model M3,model M1 exhibited slightly increased overall joint range of motion during extension and left bending,while no significant changes were observed in other aspects,and the L1-L5 lumbar segments did not reach an unstable state.(4)In model M1,the maximum Von Mises stress of the intervertebral discs increased most significantly under flexion and extension loading conditions.However,under left lateral bending,right lateral bending,left rotation,and right rotation loading conditions,the increase did not exceed 5％.(5)These findings suggest that due to the sagittal anatomical characteristics of the facet joints,the unilateral laminotomy for bilateral decompression technique,while decompressing,involves resection of more facet joints,which impacts overall segmental stability.The transforaminal endoscopic lumbar decompression technique is suitable for patients with foraminal stenosis but cannot achieve complete decompression for those with severe ventral central stenosis.The Cross-Overtop technique effectively enlarges the volume of the central canal and lateral recess,optimizing decompression,and shows unique advantages in treating upper lumbar spinal stenosis.

The clustered regularly interspaced short palindromic repeats (CRISPR)/associated protein 9 (CRISPR /Cas9) immune system is an adaptive immune system widely distributed in bacteria and archaea. It precisely defends against invasion by exogenous phages, viruses, and plasmids through sequence-specific endogenous immune response mechanisms. As the most prominent member of this family, the CRISPR/Cas9 system has evolved into the most widely applied, flexible, and efficient technical platform in the field of genome engineering due to its exceptional genome modification capabilities. Within the CRISPR/Cas9 system, the Cas9 protein, precisely guided by a single-stranded guide RNA (gRNA), can specifically recognize target DNA sequences and induce double-strand breaks. This activates the cell’s DNA repair mechanisms, enabling gene knockout, knock-in, or modification. Demonstrating significant advantages in specificity, flexibility, and operability, CRISPR/Cas9 technology has shown immense potential in the medical field, opening new avenues for modernizing traditional Chinese medicine (TCM) research. On one hand, this technology can be used to construct precise disease models and tailor personalized treatment plans. It enables in-depth elucidation of the molecular mechanisms underlying the action targets and signaling pathways of TCM formulas and active components, thereby unraveling the scientific secrets of their complex mechanisms of action. On the other hand, it demonstrates powerful tool value in improving TCM germplasm resources, identifying and screening superior varieties, evaluating the controllability of TCM quality, and producing innovative drugs, providing technical support for the standardization and precision of TCM. Simultaneously, the high-throughput omics data generated by CRISPR technology is driving artificial intelligence (AI) to construct virtual disease models and drug prediction systems. This empowers the intelligent screening of effective TCM components, the precise prediction of potential targets, and the exploration of “reducing toxicity while enhancing efficacy” through formula combinations. This synergistic innovation between CRISPR and AI aligns perfectly with precision medicine’s urgent demand for personalized, efficient drug development, injecting new momentum into the modernization and transformation of TCM. This paper first systematically reviews and explains the developmental trajectory, structural basis, and action mechanisms of the CRISPR/Cas9 system, tracing its scientific evolution from a bacterial immune system to a gene-editing tool. It then comprehensively outlines the current state of convergence between precision medicine concepts and modernization research in TCM, analyzing the synergistic points and potential spaces for their integration. Against the backdrop of rapid precision medicine advancement, this paper emphasizes how CRISPR/Cas9 gene editing technology empowers in-depth analysis of TCM mechanisms—including specific applications in disease model construction, therapeutic target validation, and multi-target network regulation studies. It further elaborates on its multidimensional practical contributions to modernizing TCM, spanning key domains such as germplasm resource innovation, bioactive compound biosynthesis, quality standardization control, and novel TCM drug development. Finally, this paper envisions the future landscape of deep integration between CRISPR technology and AI: from data-driven intelligent drug screening to high-throughput precision discovery of effective TCM components, and further to intelligent model construction based on “reducing toxicity while enhancing efficacy” mechanisms. The synergistic convergence of these multidimensional technologies will pioneer new scientific paradigms and translational pathways for TCM modernization, propelling TCM toward leapfrogging development in the era of precision medicine.

BACKGROUND:Upper lumbar spinal stenosis is a multifactorial degenerative disorder of the spine.For narrowing of the spinal canal in the upper lumbar region(L1-L4),surgical decision-making is particularly complex.Existing minimally invasive surgeries each have their own advantages and limitations.Currently,there are few reports on biomechanical comparison and finite element analysis of different surgical methods for the treatment of high lumbar spinal stenosis.OBJECTIVE:To analyze the biomechanical impact of endoscopic unilateral laminotomy for bilateral decompression,transforaminal endoscopic lumbar decompression,and cross-overtop decompression in the treatment of upper lumbar spinal stenosis using endoscopy,and to verify the reliability and effectiveness of these three surgical techniques in treating upper lumbar spinal stenosis,providing a biomechanical basis for clinical decision-making.METHODS:The CT images of the lumbar spine of a healthy volunteer were selected,and the finite element model M0 of the normal lumbar L1-L5 segments was established using Mimics,Geomagic,Solid works,and Ansys software.The L2-L3 segment,representing upper lumbar characteristics,was chosen.Based on this model,the surgical models for endoscopic unilateral laminotomy for bilateral decompression(M1),transforaminal endoscopic lumbar decompression(M2),and cross-overtop decompression(M3)were established.Using software,the changes in the range of motion of the entire lumbar segment and the maximum Von Mises stress of the intervertebral discs were simulated and evaluated for each group of models under six loading conditions:flexion,extension,left lateral bending,right lateral bending,left rotation,and right rotation.RESULTS AND CONCLUSION:(1)Compared with model MO,the range of motion in M1,M2,and M3 increased under all six conditions,with M1 showing a greater increase.(2)M1 and M2 demonstrated significant increases in range of motion under forward bending,extension,and right rotation,while the increase under other conditions remained below 7％.(3)Compared with model M3,model M1 exhibited slightly increased overall joint range of motion during extension and left bending,while no significant changes were observed in other aspects,and the L1-L5 lumbar segments did not reach an unstable state.(4)In model M1,the maximum Von Mises stress of the intervertebral discs increased most significantly under flexion and extension loading conditions.However,under left lateral bending,right lateral bending,left rotation,and right rotation loading conditions,the increase did not exceed 5％.(5)These findings suggest that due to the sagittal anatomical characteristics of the facet joints,the unilateral laminotomy for bilateral decompression technique,while decompressing,involves resection of more facet joints,which impacts overall segmental stability.The transforaminal endoscopic lumbar decompression technique is suitable for patients with foraminal stenosis but cannot achieve complete decompression for those with severe ventral central stenosis.The Cross-Overtop technique effectively enlarges the volume of the central canal and lateral recess,optimizing decompression,and shows unique advantages in treating upper lumbar spinal stenosis.

BackgroundAdverse childhood experiences （ACEs） are strong predictors of psychopathology across the lifespan， exerting extensive adverse effects on physical and mental health during early development. While ACEs increase the risk of childhood psychopathology， sleep quality and impair cognitive function， the early neurobiological mechanisms mediating ACE-induced cognitive impairment remain unclear. ObjectiveTo explore the association between ACEs exposure and the risk of psychopathology， sleep disorders， and cognitive function， and to examine the mediating role of the putamen volume in the relationship between ACEs and cognitive function from a neurodevelopment perspective. MethodsData were obtained from the Adolescent Brain Cognitive Development （ABCD） study， comprising 10 572 children aged 9 to 10. Participants were categorized into five groups based on the cumulative score of ACEs reported by their parents and the children themselves： no-exposure group （0 types of ACEs）， the one-exposure group， the two-exposure group， the three-exposure group， and the high-risk exposure group （≥ 4 types of ACEs）. Logistic regression analysis was employed to evaluate the association between ACEs and psychopathological symptoms ［T score of the Child Behavior Checklist （CBCL） ≥ 65］. Multiple linear regression analysis was ultilized to analyze the correlations between ACEs and the scores of the Sleep Disturbance Scale for Children （SDSC）， the NIH Toolbox Cognition Battery （NIHTB-CB）， as well as the multiple structures in the cerebral cortex and subcortex. The Bootstrap method was applied to test the mediating effect of the putamen volume between ACEs and neurocognitive function. ResultsAfter adjusting for confounders， ACEs cumulative score was correlated with children's psychopathological symptoms in a dose-response manner. Compared with the no-exposed group， the high-risk exposure group had a 2.08-fold （OR=2.080， 95% CI： 1.401–3.088） increased risk of internalizing problems and a 3.13-fold （OR=3.132， 95% CI： 1.703–5.760） increased risk of externalizing problems， and the risk of conduct problems was 4.68 times that of the no-exposed group （OR=4.681， 95% CI： 2.528–8.669）. ACEs cumulative score positively predicted the total score of SDSC （β=0.080， 95% CI： 0.059–0.102）， with relatively stronger predictive effects on sleep-wake transition disorder （β=0.086， 95% CI： 0.063–0.109） and sleep onset and maintenance disorder （β=0.066， 95% CI： 0.043–0.089）. In terms of neurocognition and brain structure， ACEs cumulative score negatively predicted the overall cognitive composite score （β=-0.025， 95% CI： -0.050–-0.001）， the crystallized cognitive composite score （β=-0.035， 95% CI： -0.060–-0.010）， the volume of the left putamen nucleus （β=-0.025， 95% CI： -0.046– 0.003）， and the volume of the right putamen nucleus （β=-0.023， 95% CI： -0.044– 0.003）. The total putamen volume played a partial mediating role between ACEs and the overall cognitive composite score， the effect value was -0.002 （95% CI： -0.004–-0.001）， accounting for 7.49% of the total effect. ConclusionACEs exposure may increase the risk of psychopathological and sleep disturbances in children and may impair neurocognitive function. Reduced putamen volume may serve a potential neurobiological pathway underlying the impact of ACEs on childhood cognition. ［Funded by National Natural Science Foundation of China-Young Scientists Program （number， 82401763）； Sichuan University West China Hospital Full-time Postdoctoral Research and Development Fund Project （number， 2023HXBH084）］

BACKGROUND:Osteoporotic vertebral fractures are the most common complication in patients with osteoporosis.As a new imaging technique,spine magnetic resonance imaging(MRI)is much more sensitive than X-ray film in the diagnosis of osteoporotic vertebral fractures.However,total spine MRI is costly and takes a long time to scan.Therefore,there is no consensus on whether all patients with osteoporotic vertebral fractures need to undergo total spine MRI scan and which patients need to undergo total spine MRI. OBJECTIVE:To analyze the distribution characteristics of vertebral fractures and explore their clinical significance by observing the whole spine MRI data of osteoporotic vertebral fractures patients. METHODS:Data of cases and MRI images of all patients diagnosed with fresh osteoporotic vertebral fractures who visited the Department of Orthopedics,Affiliated Hospital of Southwest Medical University from August 2018 to September 2022 were retrospectively analyzed.903 patients were included in the study based on inclusion and exclusion criteria.General information(age,gender,and body mass index),medical history characteristics(duration of illness,history of trauma surgery,percussion pain area,and pain score)were collected.The characteristics of vertebral fractures were analyzed through whole spine magnetic resonance imaging.Firstly,based on the number of vertebral fractures in patients,they were divided into the single vertebral fracture group(484 cases)and the multi-vertebral fracture group(419 cases),and the differences were analyzed between the two groups.Then,based on whether the farthest interval between the fractured vertebrae was greater than or equal to 5,the multi vertebral fracture group was further divided into two subgroups.Among them,Group A(the farthest interval between the fractured vertebrae was less than 5)contained 306 cases;Group B(with the farthest interval between fractured vertebral bodies greater than 5)included 113 cases.The differences were analyzed between two subgroups. RESULTS AND CONCLUSION:(1)Among 903 patients,419 patients(46.4%)had more than two fractured vertebrae.There were 654 patients(72.4%)with thoracolumbar fractures,and 54 patients(6%)with fractures in the thoracic plus lumbar region and the entire thoracic to lumbar region.In group B,96.5%of patients had multiregional percussion pain.(2)Compared with the patients in the single vertebral fracture group and the multi-vertebral fracture group,there were significant differences in bone mineral density,whether the medical history was greater than or equal to 1 month,the history of low energy injury,and the distribution and number of axial percussion pain areas in the spine during physical examination between the two groups(P<0.05).Age,gender,body mass index,whether there was underlying disease,pain visual analog scale score,whether there was a history of elderly thoracolumbar fracture,and whether there was a history of thoracolumbar surgery,and the number of fractured vertebrae had no statistical significance(P>0.05).(3)There were statistically significant differences between the Groups A and B in bone mineral density,the distribution and quantity of percussion pain area,and the history of low energy injury(P<0.05).There were no significant differences in age,gender,history of old fractures,visual analog scale score,body mass index,whether the medical history was longer than or equal to 1 month,history of underlying diseases,and history of thoracolumbar surgery between the two groups(P>0.05).(4)Patients with multiple low-energy trauma history,history of more than 1 month,multiple percussion pain,and the lower bone mineral density should be alert to the occurrence of multiple vertebral fracture and jump fracture.We recommend the whole spinal MRI for these patients.

BACKGROUND:Zinc-based alloy medical implant materials have excellent mechanical properties,complete degradability and good biocompatibility,and are mainly used in orthopedic implants,cardiovascular stents,bile duct stents,tracheal stents,nerve catheters,etc. OBJECTIVE:To review the research progress of biodegradable zinc-based alloys in bone defect repair and prospect the promising research direction and achievements of zinc-based materials. METHODS:After searching PubMed,Web of Science,WanFang Data,and CNKI databases from the establishment of the database to June 2023,various relevant articles on biodegradable zinc-based alloys for bone implant material research were collected.The basic characteristics of biodegradable zinc based alloys were summarized,and the role of zinc-based alloys in promoting bone tissue repair was sorted and summarized.The current research hotspots and shortcomings were discussed. RESULTS AND CONCLUSION:(1)Zinc-based alloys have good biocompatibility.Using zinc-based alloys as the matrix material,with the help of scaffold structure construction technology and coating optimization process,the bone conductivity of zinc-based alloys will be effectively improved,and their degradation products will have efficient bone induction to regulate the gene expression of osteoblasts and osteoclasts,thereby promoting the repair and reconstruction of bone defects.(2)However,in the research on optimizing zinc-based alloys,the coating process is relatively insufficient,and additive loading technology is still lacking.(3)Zinc-based alloys have excellent mechanical and biological properties.Through special processes,their bone conductivity and osteoinductivity can be increased to effectively improve their ability to promote bone repair and reconstruction,and it is expected to further achieve the development of personalized transplant materials.Further research and development are needed to optimize the integration of coating and additive loading technologies into zinc-based alloys.

BackgroundGraduate students frequently face life events， many of which may adversely affect their mental well-being. However， the interaction between life events and the development of depression， anxiety， and somatic symptoms remains unclear. ObjectiveTo explore the relationship between life events and the development of depressive， anxiety and somatic symptoms in graduate students， thereby informing prevention strategies for these conditions. MethodsA sample of 6 722 newly enrolled graduate students at a comprehensive university in Southwest China from September to November 2018 was selected. The assessment was conducted using the Adolescent Self-rating Life Events Checklist （ASLEC）， the 7-item Generalized Anxiety Disorder scale-7 item （GAD-7）， the Patient Health Questionnaire Depression Scale-9 item （PHQ-9）， and the Patient Health Questionnaire-15 （PHQ-15）. Network analysis was implemented by using the bootnet and qgraph packages in the R software （version 4.2.3）， with centrality indices calculated to identify core and bridge symptoms within the network. ResultsThe study encompassed a total of 6 171 graduate students， representing 91.80% of the target population. The prevalence rates of anxiety， depressive， and somatic symptoms among graduate students were 12.59% （777/6 171）， 16.63% （1 026/6 171）， and 27.66% （1 707/6 171）， respectively. Network analysis revealed that 'academic stress' was the core symptom with the highest strength and expected influence （both values=1.207）， while 'feeling down， depressed， or hopeless' was the bridge symptom with the highest bridge strength and bridge expected influence （both values=0.454）. There was no significant difference in global network strength and edge weight between women and men （P>0.05）. ConclusionAcademic stress， emerging as the core symptom， assumes a dominant position within the symptom network and exhibits strong interactions with other negative affective states. There was no gender difference in the network structure.

ObjectiveTo explore the mechanism of Huoxue Rongluo prescription （HXRLP） in repairing the blood-brain barrier （BBB） after ischemic stroke （IS）. MethodsMale C57BL/6 mice were randomly divided into sham operation （Sham） group， cerebral infarction model （MCAO） group， environmental circadian disruption with cerebral infarction model （ECD-MCAO） group， low-， medium-， and high-dose HXRLP （HXRLP-L， M， and H） groups （8.5， 17， 34 g·kg^-1·d^-1， respectively）， and positive drug butylphthalide （NBP） group （0.23 mL·d^-1）. In the Sham group， only the exposed blood vessels were isolated without suture insertion. In the other groups， the middle cerebral artery occlusion （MCAO） model of mice was prepared. In the ECD-MCAO group， HXRLP groups， and NBP group， the environmental circadian disruption （ECD） model was prepared. The mice in the Sham group， MCAO group， and ECD-MCAO group were given the same volume of soybean oil by gavage， while those in the other groups were given the corresponding drugs by gavage. Samples were collected after 7 consecutive days of administration. The mNSS score was used to evaluate the repair effect of HXRLP on neurological deficits after IS. Hematoxylin-eosin （HE） staining was used to assess the impact of HXRLP on the pathological damage of brain tissue after IS. 2，3，5-Triphenyltetrazolium chloride （TTC） staining and cerebral blood perfusion status were used to evaluate the repair effect of HXRLP on brain tissue damage after IS. Evans blue staining and transmission electron microscopy were used to evaluate the improvement effect of HXRLP on the permeability injury of BBB after IS. Immunofluorescence （IF） staining was used to observe the expression of von Willebrand Factor （vWF）， brain and muscle Arnt-like 1 （Bmal1）， and Occludin in brain tissue. Western blot was used to detect the protein expression of Bmal1， Occludin， tight junction protein （Claudin-5）， vascular endothelial growth factor （VEGF）， and angiopoietins（Ang）， and related analysis was conducted. ResultsCompared with the Sham group， the MCAO group exhibited significantly aggravated neurological deficits， cerebral infarction volume， brain pathological damage， and BBB leakage （P0.01） and significantly reduced cerebral blood perfusion （P0.01）. The expression of Bmal1， vWF， vascular endothelial growth factor A （VEGFA）， and Ang in brain tissue was significantly enhanced （P0.01）， while the expression of Occludin and Claudin-5 was significantly weakened （P0.01）. Compared with the MCAO group， the ECD-MCAO group showed significantly aggravated neurological deficits， cerebral infarction volume， and BBB leakage （P0.01）， obviously worsened brain pathological damage （P0.05）， significantly reduced cerebral blood perfusion （P0.01）， and significantly decreased expression of Bmal1， vWF， VEGFA， Ang， Occludin， and Claudin-5 in brain tissue （P0.01）. Compared with the ECD-MCAO group， the HXRLP groups of all doses presented significantly improved neurological deficits， cerebral infarction volume， brain pathological damage， and BBB leakage （P0.01）， significantly increased cerebral blood perfusion （P0.01）， and enhanced expression levels of Bmal1， vWF， VEGFA， Ang， Occludin， and Claudin-5 in brain tissue （P0.01）. ConclusionHXRLP can regulate the clock protein Bmal1 and promote the expression of VEGFA， Ang， Occludin， and Claudin-5， thereby improving BBB damage after IS.

Diabetic cardiomyopathy （DCM）， a cardiovascular complication caused by diabetes mellitus， is a major cause of heart failure and even sudden cardiac death in diabetic patients. Traditional Chinese medicine （TCM） posits that the core pathogenesis of DCM lies in internal deficiency and superficial excess， characterized by deficiency of both Qi and Yin combined with phlegm and blood stasis. Modern medical treatments for DCM primarily focus on blood glucose control and symptom alleviation yet lack targeted therapeutic strategies. In contrast， TCM offers a wealth of practical experience and a complete theoretical system， demonstrating definite clinical efficacy and high medication safety in DCM management. As a classic formula for tonifying Qi and nourishing Yin， Shengmaisan comprises Ginseng Radix et Rhizoma， Ophiopogonis Radix， and Schisandrae Chinensis Fructus. It contains multiple bioactive components， including ginsenosides， ophiopogonin， schisandrins， and homoisoflavonoids， which exhibit cardioprotective properties. The therapeutic mechanisms of Shengmaisan-like formulae for DCM involve enhancing myocardial contractility， attenuating myocardial fibrosis， modulating mitochondrial quality control， regulating glucose metabolism， mitigating oxidative stress， and suppressing inflammatory responses. Clinically， Shengmaisan-like formulae not only manage hyperglycemic status but also ameliorate cardiac structural and functional impairments and enhance exercise tolerance in DCM patients， playing a vital role in the prevention， treatment， and rehabilitation of DCM. This paper analyzes the feasibility of Shengmaisan-like formulae in DCM management and synthesizes current research achievements regarding their chemical components， mechanisms of action， and clinical applications， aiming to provide a scientific foundation for the use of such formulae in the treatment of DCM.

BACKGROUND: The available evidence regarding the benefits of percutaneous coronary intervention (PCI) on patients receiving dialysis with coronary artery disease (CAD) is limited and inconsistent. This study aimed to evaluate the association between PCI and clinical outcomes as compared with medical therapy alone in patients undergoing dialysis with CAD in China. METHODS: This multicenter, retrospective study was conducted in 30 tertiary medical centers across 12 provinces in China from January 2015 to June 2021 to include patients on dialysis with CAD. The primary outcome was major adverse cardiovascular events (MACE), defined as a composite of cardiovascular death, non-fatal myocardial infarction, and non-fatal stroke. Secondary outcomes included all-cause death, the individual components of MACE, and Bleeding Academic Research Consortium criteria types 2, 3, or 5 bleeding. Multivariable Cox proportional hazard models were used to assess the association between PCI and outcomes. Inverse probability of treatment weighting (IPTW) and propensity score matching (PSM) were performed to account for potential between-group differences. RESULTS: Of the 1146 patients on dialysis with significant CAD, 821 (71.6%) underwent PCI. After a median follow-up of 23.0 months, PCI was associated with a 43.0% significantly lower risk for MACE (33.9% [ n  = 278] vs . 43.7% [ n  = 142]; adjusted hazards ratio 0.57, 95% confidence interval 0.45-0.71), along with a slightly increased risk for bleeding outcomes that did not reach statistical significance (11.1% vs . 8.3%; adjusted hazards ratio 1.31, 95% confidence interval, 0.82-2.11). Furthermore, PCI was associated with a significant reduction in all-cause and cardiovascular mortalities. Subgroup analysis did not modify the association of PCI with patient outcomes. These primary findings were consistent across IPTW, PSM, and competing risk analyses. CONCLUSION This study indicated that PCI in patients on dialysis with CAD was significantly associated with lower MACE and mortality when comparing with those with medical therapy alone, albeit with a slightly increased risk for bleeding events that did not reach statistical significance.
Humans ; Percutaneous Coronary Intervention/methods* ; Male ; Female ; Coronary Artery Disease/drug therapy* ; Retrospective Studies ; Renal Dialysis/methods* ; Middle Aged ; Aged ; China ; Proportional Hazards Models ; Treatment Outcome