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        west china medical publishers
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        find Keyword "modification" 38 results
        • Research progress on 3D printing ceramic-polymer composite for bone repair

          Traditional bone repair materials, such as titanium, polyetheretherketone, and calcium phosphate, exhibit limitations, including poor biocompatibility and incongruent mechanical properties. In contrast, ceramic-polymer composite materials combine the robust mechanical strength of ceramics with the flexibility of polymers, resulting in enhanced biocompatibility and mechanical performance. In recent years, researchers worldwide have conducted extensive studies to develop innovative composite materials and manufacturing processes, with the aim of enhancing the bone repair capabilities of implants. This article provides a comprehensive overview of the advancements in ceramic-polymer composite materials, as well as in 3D printing and surface modification techniques for composite materials, with the objective of offering valuable insights to improve and facilitate the clinical application of ceramic-polymer composite materials in the future.

          Release date:2023-10-24 03:04 Export PDF Favorites Scan
        • PRELIMINARY STUDY ON EFFECTS OF HUMAN BRAIN-DERIVED NEUROTROPHIC FACTOR GENE-MODIFIED BONE MARROW MESENCHYMAL STEM CELLS BY INTRAVENOUS TRANSPLANTATION ON STRUCTURE AND FUNCTION OF RAT INJURED SPINAL CORD

          Objective To transplant intravenously human brain-derived neurotrophic factor (hBDNF) genemodified bone marrow mesenchymal stem cells (BMSCs) marked with enhanced green fluorescent protein (EGFP) to injured spinal cord of adult rats, then to observe the viabil ity of the cells and the expressions of the gene in spinal cord, as well as theinfluence of neurological morphological repairing and functional reconstruction. Methods Ninety-six male SD rats weighing (250 ± 20) g were randomly divided into 4 groups: hBDNF-EGFP-BMSCs transplantation group (group A, n=24), Ad5-EGFPBMSCs transplantation group (group B, n=24), control group (group C, n=24), and sham operation group (group D, n=24). In groups A, B, and C, the spinal cord injury models were prepared according to the modified Allen method at the level of T10 segment, and after 3 days, 1 mL hBDNF-EGFP-BMSCs suspension, 1 mL Ad5-EGFP-BMSCs suspension and 1 mL 0.1 mol/L phosphate buffered sal ine (PBS) were injected into tail vein, respectively; in group D, the spinal cord was exposed without injury and injection. At 24 hours after injury and 1, 3, 5 weeks after intravenous transplantation, the structure and neurological function of rats were evaluated by the Basso-Beattie-Bresnahan (BBB) score, cortical somatosensory evoked potential (CSEP) and transmission electron microscope. The viabil ity and distribution of BMSCs in the spinal cord were observed by fluorescent inverted phase contrast microscope and the level of hBDNF protein expression in the spinal cord was observed and analyzed with Western blot. Meanwhile, the expressions of neurofilament 200 (NF-200) and synaptophysin I was analyzed with immunohi stochemistry. Results After intravenous transplantation, the neurological function was significantly improved in group A. The BBB scores and CSEP in group A were significantly higher than those in groups B and C (P lt; 0.05) at 3 and 5 weeks. The green fluorescence expressions were observed at the site of injured spinal cord in groups A and B at 1, 3, and 5 weeks. The hBDNF proteinexpression was detected after 1, 3, and 5 weeks of intravenous transplantation in group A, while it could not be detected in groups B, C, and D by Western blot. The expressions of NF-200 and synaptophysin I were ber and ber with transplanting time in groups A, B, and C. The expressions of NF-200 and synaptophysin I were best at 5 weeks, and the expressions in group A were ber than those in groups B and C (P lt; 0.05). And the expressions of NF-200 in groups A, B, and C were significantly ber than those in group D (P lt; 0.05), whereas the expressions of synaptophysin I in groups A, B, and C were significantly weaker than those in group D (P lt; 0.05). Ultramicrostructure of spinal cords in group A was almost normal. Conclusion Transplanted hBDNF-EGFP-BMSCs can survive and assemble at the injured area of spinal cord, and express hBDNF. Intravenous implantation of hBDNF-EGFP-BMSCs could promote the restoration of injured spinal cord and improve neurological functions.

          Release date:2016-08-31 05:48 Export PDF Favorites Scan
        • Standardization and surgical modification of sleeve gastrectomy with jejunojejunal bypass

          ObjectiveTo analyze why sleeve gastrectomy (SG) with jejunojejunal bypass (SG-JJB), despite being the second most common bariatric procedure in China, has not been recommended in national and international guidelines nor endorsed by expert consensus; to investigate the primary obstacles to its standardization and widespread adoption; and to propose strategies leveraging China’s extensive clinical experience to refine the technique, establish standardized protocols, and address existing challenges, thereby defining its future role in metabolic surgery. MethodsBy systematically reviewing the evolution, current evidence profile, and distinctive features of SG-JJB compared to other SG-Plus procedures, this study aimed to identify constraints hindering its adoption. Concurrently, considering the characteristics of domestic healthcare resources, we explored the feasibility of procedural refinements, key steps for standardization, and solutions to potential challenges, thereby facilitating the optimization and standardization of SG-JJB. ResultsThe three key constraints hindering SG-JJB development were: risks of blind loop syndrome, uncertainty regarding optimal bypass limb length, and limited evidence on long-term efficacy. To address these issues, this study proposed leveraging China’s clinical and multi-center collaboration strengths to: conduct high-quality studies defining the impact of bypass length on outcomes, establish unified diagnostic and monitoring protocols for blind loop syndrome, and systematically collect longitudinal data to evaluate long-term efficacy, thereby informing evidence-based surgical standardization. ConclusionsSG-JJB holds significant potential in Chinese bariatric-metabolic practice, yet its standardization faces persistent challenges. Addressing concerns about blind loop syndrome, defining optimal bypass limb length, and accumulating robust long-term efficacy data are pivotal for advancing SG-JJB standardization and adoption. Leveraging domestic clinical resources through multi-center collaborations, high-quality research, and evidence-based protocol development is the essential pathway to overcoming these barriers, achieving standardized implementation, and securing recognition in authoritative guidelines.

          Release date:2025-09-22 03:59 Export PDF Favorites Scan
        • RESEARCH PROGRESS IN SURFACE MODIFICATION OF ORTHOPAEDIC IMPLANTS VIA EXTRACELLULAR MATRIX COMPONENTS

          Objective To review the research progress of promoting the bone formation at early stage by components of the extracellular matrix (ECM). Methods Recent literature concerning the influence of these components on new bone formation and bone/implant contact was extensively reviewed and summarized. Results Coating of titanium or hydroxyapatite implants with organic components of the ECM (such as collagen type I, chondroitin sulfate, and Arg-Gly-Asp peptide) offers great potential to improve new bone formation and enhance bone/implant contact, which in turn will shorten recovery time and improve implant stability. Conclusion The increasing knowledge about the role of the ECM for recruitment, proliferation, differentiation of cells, and regeneration of tissue will eventually deal to the creating of an artificial ECM on the implant that could allow a defined adjustment of the required properties to support the healing process.

          Release date:2016-08-31 04:05 Export PDF Favorites Scan
        • Research progress in epigenetic research on the pathogenesis of retinoblastoma

          Retinoblastoma (RB) is a common intraocular tumor in children, often leading to blindness or disability, and its pathogenesis involves genetic and epigenetic regulation. Epigenetics regulates gene expression through mechanisms such as DNA methylation and histone modification without altering the DNA sequence, and the imbalance of its homeostasis is considered a crucial factor in the development and progression of RB. Therapeutic strategies targeting these abnormal modifications offer new potential treatment avenues for RB. Although current research has highlighted the importance of epigenetics in RB, the specific mechanisms of action, the relationship with genetic bases, and the development of targeted drugs remain largely unknown. Therefore, further in-depth research into the epigenetic mechanisms of RB is of great significance for elucidating its carcinogenic mechanisms, identifying effective therapeutic targets, and developing new drugs.

          Release date:2025-07-17 09:24 Export PDF Favorites Scan
        • LEARNING AND MEMORY AMELIORATION OF TRANSPLANTATION OF THE NEURAL STEM CELLS MODIFIED WITH HUMAN BRAIN-DERIVED NEUROTROPHIC FACTOR GENE ON ALZHEIMERDISEASE MODEL RAT

          Objective To investigate the memory amelioration of the Alzheimer disease (AD)model rat after being transplanted the single neural stem cells(NSC) and NSC modified with human brain-derived neurotrophic factor(hBDNF) gene. Methods Forty SD rats were divided evenly into 4 groups randomly. The AD model rats were made by cutting unilaterallythe fibria fornix of male rats. Ten to twelve days after surgery, the genetically modified and unmodified NSC were implanted into the lateral cerebral ventricle of group Ⅲ and group Ⅳ respectively. Two weeks after transplantation, theamelioration of memory impairment of the rats was detected by Morris water maze. Results The average escaping latency of the group Ⅲ and group Ⅳ (41.84±21.76 s,25.23±17.06 s respectively) was shorter than that of the group Ⅱ(70.91±23.67 s) (Plt;0.01). The percentage of swimming distance inthe platform quadrant in group Ⅲ (36.9%) and in group Ⅳ(42.0%) was higherthan that in the group Ⅱ(26.0%) (Plt;0.01). More marginal and random strategies were used in group Ⅱ.The percentage of swimming distance in the platform quadrant in group Ⅳ was also greater than that in group Ⅲ(Plt;0.05). There were no significant differences in the average escaping latency, the percentage of swimming distance in the platform quadrant and the probe strategy between group Ⅳ and group Ⅰ(Pgt;0.05).More lineal and oriented strategies were used in group Ⅳ. Conclusion The behavioral amelioration of AD model rat was obtained by transplanting single NSC and hBDNF-gene-modified NSC. The effect of the NSC group modified with hBDNF gene is better than that of the groupⅢ.

          Release date:2016-09-01 09:29 Export PDF Favorites Scan
        • The effect of surface modification strategies on biological activity of titanium implant

          The surface morphology of titanium metal is an important factor affecting its hydrophilicity and biocompatibility, and exploring the surface treatment strategy of titanium metal is an important way to improve its biocompatibility. In this study, titanium (TA4) was firstly treated by large particle sand blasting and acid etching (SLA) technology, and then the obtained SLA-TA4 was treated by single surface treatments such as alkali-heat, ultraviolet light and plasma bombardment. According to the experimental results, alkali-heat treatment is the best treatment method to improve and maintain surface hydrophilicity of titanium. Then, the nanowire network morphology of titanium surface and its biological property, formed by further surface treatments on the basis of alkali-heat treatment, were investigated. Through the cell adhesion experiment of mouse embryonic osteoblast cells (MC3T3-E1), the ability of titanium material to support cell adhesion and cell spreading was investigated after different surface treatments. The mechanism of biological activity difference of titanium surface formed by different surface treatments was investigated according to the contact angle, pit depth and roughness of the titanium sheet surface. The results showed that the SLA-TA4 titanium sheet after a treatment of alkali heat for 10 h and ultraviolet irradiation for 1 h has the best biological activity and stability. From the perspective of improving surface bioactivity of medical devices, this study has important reference value for relevant researches on surface treatment of titanium implantable medical devices.

          Release date:2024-06-21 05:13 Export PDF Favorites Scan
        • Advances in surface modification of orthopedic titanium implants for anti-infection

          Titanium and its alloys have become one of the most widely used implant materials in orthopedics because of their excellent mechanical properties and biocompatibility. Implant-associated infection is the main reason of failure of orthopedic implant surgery. The anti-infection modification of implant surface has received more attention in the field of infection prevention and developed rapidly. This article focuses on the current research status of simple anti-infection surface modifications that make titanium implants possess anti-adhesion, bactericidal activity or antibacterial membrane activity, as well as the research progress of composite functional surface modifications that promote bone integration, osteogenesis or immunomodulatory effects on the basis of anti-infection, so as to provide references for the construction of orthopedic implants with composite functions.

          Release date:2023-10-24 03:04 Export PDF Favorites Scan
        • Research on Molecular Biological Characteristics of Proto-oncogene pim-2

          The purpose of this paper is to present the research on the molecular biological characteristics of proto-oncogene pim-2 and to analyze the related mechanism. Proto-oncogene pim-2 was studied and analyzed by the bioinformatics method and technology. With an online server, the chromosomal localization of pim-2 gene was analyzed, and the exon, open reading frame, CpG island and miRNAs complementary fragments and the like were predicted. With bioinformatics software, the physicochemical property of transcription protein of proto-oncogene pim-2 and various modification sites of protein sequence, such as ubiquitination and glycosylation, were predicted, the antigenic index was calculated, and the spatial structural was modeled. The research findings showed that the proto-oncogene pim-2 comprised six exons, the CDS (coding sequence) transcribed a section of peptide chain including 311 amino acids, a gene promoter has a CpG island, and the 3'UTR region contains an miRNA gene. The molecular weight of the Pim-2 protein was 34, 188.47, the isoelectric point was 5.78, the instability index was 45.87, and the extinction coefficient was 279nm. A plurality of covalent modification sites, two ubiquitination sites, four glycosylation sites, an SUMO sumoylation site, a nitrosation site, two palmitoylation sites and sixteen regions with higher antigenic index were distributed in the protein sequence. This research showed that the related regions and modification sites distributed on the sequence of proto-oncogene pim-2 were closely related to the carcinogenic effect thereof.

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        • STUDY ON IMPROVEMENT OF CELL AFFINITY OF POLYMER MATERIALS--MODIFIED POLY(D,L-LACTIDE) BY ANHYDROUS AMMONIA GASEOUS PLASMA

          OBJECTIVE: To modify the surface of poly(D,L-lactide) film by anhydrous ammonia gaseous plasma treatment. METHODS: The changes of contact angles were measured and surface energy were calculated. Mouse 3T3 fibroblast cells were cultured on plasma modified and control poly(D,L-lactide) films. RESULTS: It was found that the hydrophilicity and surface energy of the materials have been increased after plasma treatment. Cell culture results showed that ammonia plasma treatment could promote the cell attachment and cells growth. After 4 days culture, the cells on the plasma treated films were 2-folds quantitatively compared with that of the control films. CONCLUSION: Ammonia plasma treatment can improve the cell affinity to poly(D,L-lactide).

          Release date:2016-09-01 10:21 Export PDF Favorites Scan
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