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find Keyword "modification" 36 results
  • Advances in anti-thrombogenetic strategies of biomaterials

    The presence of thrombus on the surface of blood-contacting biomaterials in clinical practice can significantly impact both the longevity of the biomaterials and the overall survival prognosis of patients. The administration of anticoagulant and antiplatelet medications may heighten the risk of systemic bleeding. Developing biomaterials with anti-thrombogenetic properties and enabling localized anti-thrombosis may offer a solution to these challenges. The development strategies for anti-thrombogenetic biomaterials can be categorized into three main approaches based on the mechanisms of thrombus formation on biomaterial surfaces: altering physical and chemical properties, designing coatings containing or releasing active substances, and promoting endothelialization. However, due to the intricate and interconnected nature of these mechanisms, biomaterials constructed using a single approach may not effectively prevent thrombus formation. The collaborative intervention of various mechanisms can facilitate the development of biomaterials with enhanced blood compatibility.

    Release date:2024-08-21 02:11 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 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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  • Preparation of Ti-O Film Deposited on the Surface of a New Type of Artificial Mechanical Heart Valve

    The rutile structure titanium oxide (Ti-O) film was prepared on the pure titanium material TA2 (99.999%) surface by the magnetic filter high vacuum arc deposition sputtering source. The method can not only maintain the material mechanical properties, but also improve the surface properties for better biocompatibility to accommodate the physiological environment. The preparation process of the Ti-O film was as follows. Firstly, argon ions sputtered to the TA2 substrate surface to remove the excess impurities. Secondly, a metal ion source generated Ti ions and oxygen ions by the RF discharge. Meanwhile a certain negative bias was imposed on the sample. There a certain composition of Ti-O film was obtained under a certain pressure of oxygen in the vacuum chamber. Finally, X-ray diffraction was used to research the structure and composition of the film. The results showed that the Ti-O film of the rutile crystal structure was formed under the 0.18 Pa oxygen partial pressure. A Nano scratch experiment was used to test the coating adhesion property, which demonstrated that the film was stable and durable. The contact angle experiment and the platelet clotting experiment proved that the modified surface method had improved platelet adhesion performance, and, therefore, the material possessed better biocompatibility. On the whole, the evaluations proved the modified material had excellent performance.

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  • Research progress of antibacterial modification of orthopaedic implants surface

    ObjectiveTo summarize the related research progress of antibacterial modification of orthopaedic implants surface in recent years. Methods The domestic and foreign related literature in recent years was extensively consulted, the research progress on antibacterial modification of orthopaedic implants surface was discussed from two aspects of characteristics of infection in orthopedic implants and surface anti-infection modification. Results The orthopaedic implants infections are mainly related to aspects of bacterial adhesion, decreased host immunity, and surface biofilm formation. At present, the main antimicrobial coating methods of orthopaedic implants are antibacterial adhesion coating, antibiotic coating, inorganic antimicrobial coating, composite antimicrobial coating, nitric oxide coating, immunomodulation, three-dimensional printing, polymer antimicrobial coating, and “smart” coating. Conclusion The above-mentioned antibacterial coating methods of orthopedic implants can not only inhibit bacterial adhesion, but also solve the problems of low immunity and biofilm formation. However, its mechanism of action and modification are still controversial and require further research.

    Release date:2022-05-07 02:02 Export PDF Favorites Scan
  • EXPERIMENTAL STUDY ON VASCULAR ENDOTHELIAL GROWTH FACTOR 165 GENE-MODIFIED RAT HAIR FOLLICLE STEM CELLS MEDIATED BY LENTIVIRAL VECTOR

    ObjectiveTo obtain rat hair follicle stem cells (rHFSCs) which can constantly and highly express vascular endothelial growth factor 165 (VEGF165), and to observe the expression of VEGF165 gene in rat HFSCs. MethodsThe cirri skin of 1-week-old Sprague Dawley rat was harvested and digested by using combination of Dispase and type IV collagenases. The bulge was isolated under microscope. The rHFSCs were cultured by tissue block method. After purified by rapid adhering on collagen type IV, the growth curve of different generations rHFSCs was drawn. The cells were identified by immunofluorescence staining and real time quantitative PCR (RT-qPCR) analysis that tested the expression level of correlated genes. Lentivirus of pLV-internal ribosome entry site (IRES)-VEGF165-enhanced green fluorescent protein (EGFP) (experimental group) and pLV-IRES-EGFP empty vector (control group) was packaged by calcium transfected method and the rHFSCs were transfected. The green fluorescent protein expression was observed by inverted fluorescence microscope, and VEGF165 mRNA and protein expressions were detected using RT-PCR and Western blot. ResultsThe rHFSCs which were isolated, cultured, and purified were like the "slabstone", and had strong adhesion ability and colony formation ability. The purified cells were in latent growth phase at 2-3 days; they were in exponential growth phase at 5-6 days. The expressions of cytokeration 15 (CK15), integrin α6, and integrin β1 (markers of HFSCs) were positive by immunocytochemistry. The RT-qPCR analysis showed that CK15, CK19, integrin α6, and integrin β1 expressed highly, but CD34 (a marker of epidermal stem cells) and CK10 (a marker of keratinocyte) expressed lowly. After 14 days, the transfection efficiency was up to 85.76%±1.91%. RT-PCR analysis and Western blot showed that VEGF165 mRNA and protein expressions were positive in experimental group, and were negative in control group. ConclusionThe rHFSCs with high purity and strong proliferation ability can be obtained by using microscope combined with tissue cultivation and rapid cell adhesion on collagen type IV. The rHFSCs with high expression of VEGF165 can be successfully obtained by lentiviral transfection. This method provides good seeding cells for tissue engineering to construct artificial hair follicles, blood vessels, and skins.

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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
  • Complex and diverse RNA modifications and cancer

    RNA can be labeled by more than 170 chemical modifications after transcription, and these chemical modifications are collectively referred to as RNA modifications. It opened a new chapter of epigenetic research and became a major research hotspot in recent years. RNA modification regulates the expression of genes from the transcriptome level by regulating the fate of RNA, thus participating in many biological processes and disease occurrence and development. With the deepening of research, the diversity and complexity of RNA modification, as well as its physiological significance and potential as a therapeutic target, can not be ignored.

    Release date:2022-11-24 03:20 Export PDF Favorites Scan
  • Relationship Between Histone Modifications and Gastrointestinal Cancer

    Objective To review the relationship between histone modifications and gastrointestinal cancer. Methods Literatures on histone modifications and the relationship between histone modifications and gastrointestinal cancer were collected and reviewed. Results Histone modifications played an important role in the establishment of gene silencing during tumorgenesis. DNA methylation and histone modifications might interact with each other and form a complex network to establish and maintain gene silencing. Restoring gene function silenced by epigenetic changes in cancer had the potential of ‘normalizing’ cancer cells, which was named epigenetic therapy. Epigenetic therapy was very promising in prevention and treatment of gastrointestinal cancer, but many unsolved issues remain which need to be addressed in future studies. Conclusion Histone modifications are associated with the pathogenesis of gastrointestinal cancer. Restoring gene function silenced by epigenetic changes may have a great role in the prevention and treatment of gastrointestinal cancer.

    Release date:2016-09-08 11:49 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
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