35 results on '"Escudero ML"'
Search Results
2. Dataset for the paper 'Barrier Graphene Oxide on a CoCr Alloy via Silane/GO Covalent Bonding and Its Electrochemical Behavior in a Simulated Synovial Fluid Electrolyte'
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García Alonso María Cristina, Lozano Puerto, Rosa María, Ministerio de Ciencia, Innovación y Universidades (España), Chico, Belén [0000-0001-8697-6298], Lozano, R. M. [0000-0003-2762-6938], García-Alonso, M. C.[0000-0003-0275-4626], Sánchez-López, Luna [0000-0002-5065-9239], Escudero, María Lorenza [0000-0002-2181-448X], García-Alonso, MC, Sánchez-López, L, García-Alonso, MC; Escudero, ML; Lozano, RM, Sánchez-López, L; Chico, B; Escudero, ML; Lozano, RM; García-Alonso, MC, Chico, B; Escudero, ML; Lozano, RM; García-Alonso, MC, Lozano, RM; García-Alonso, MC, Sánchez-López, Luna, Chico, Belén, Escudero Rincón, María Lorenza, Lozano, R. M., García-Alonso, M. C., García Alonso María Cristina, Lozano Puerto, Rosa María, Ministerio de Ciencia, Innovación y Universidades (España), Chico, Belén [0000-0001-8697-6298], Lozano, R. M. [0000-0003-2762-6938], García-Alonso, M. C.[0000-0003-0275-4626], Sánchez-López, Luna [0000-0002-5065-9239], Escudero, María Lorenza [0000-0002-2181-448X], García-Alonso, MC, Sánchez-López, L, García-Alonso, MC; Escudero, ML; Lozano, RM, Sánchez-López, L; Chico, B; Escudero, ML; Lozano, RM; García-Alonso, MC, Chico, B; Escudero, ML; Lozano, RM; García-Alonso, MC, Lozano, RM; García-Alonso, MC, Sánchez-López, Luna, Chico, Belén, Escudero Rincón, María Lorenza, Lozano, R. M., and García-Alonso, M. C. more...
- Abstract
[EN] This is the experimental dataset used in the paper “Barrier Graphene Oxide on a CoCr Alloy via Silane/GO Covalent Bonding and Its Electrochemical Behavior in a Simulated Synovial Fluid Electrolyte". The article includes the experimental procedure carried out for the deposition of graphene oxide on CoCr surfaces: CoCr was hydroxylated through alkalization in NaOH 5 M for 2 h, (sample named CoCr-OH). Subsequently, silanization was carried out using APTES. APTES was pre-mixed at 2% vol in isopropanol-water (200:1 v/v) and stirred for 1 h. After this, CoCr-OH samples were immersed in the APTES solution at room temperature for 1 min. The silane-coated samples were kept under curing conditions at 45 °C (CoCr-OH-Si45 sample) and 75 °C (CoCr-OH-Si75 sample) for 24 h and 30 min, respectively. Finally, CoCr-OH-Si45 and CoCr-OH-Si75 surfaces were immersed in 4 g/L GO aqueous suspension at 60 °C for 12 h and 24 h to obtain CoCr-OH-Si45-GO12h, CoCr-OH-Si75-GO12h and CoCr-OH-Si45-GO24h, and CoCr-OH-Si75-GO24h. This data set includes the results of the electrochemical impedance data obtained for each CoCr surface: CoCr (CoCr, CoCr-OH, CoCr-OHSi45, CoCr-OH-Si75 CoCr-OH-Si45-GO12h, CoCr-OH-Si75-GO12h y CoCr-OH-Si45-GO24h, y CoCr-OH-Si75-GO24h, immersed in 3 g/L Hyaluronic acid solution for 7 days., [ES] Este es el conjunto de datos experimentales utilizado en el artículo "Barrera de Óxido de Grafeno en una Aleación CoCr mediante enlace covalente de Silano/GO y su comportamiento electroquímico en un electrolito de fluido sinovial simulado". El artículo incluye el procedimiento experimental llevado a cabo para la deposición de óxido de grafeno sobre superficies de CoCr: CoCr fue hidroxilado mediante alcalinización en NaOH 5 M durante 2 horas (muestra denominada CoCr-OH). Posteriormente, se llevó a cabo la silanización utilizando APTES. APTES fue premezclado al 2% en volumen en isopropanol-agua (200:1 v/v) y agitado durante 1 hora. Después, las muestras de CoCr-OH fueron sumergidas en la solución de APTES a temperatura ambiente durante 1 minuto. Las muestras recubiertas con silano se mantuvieron bajo condiciones de curado a 45 °C (muestra CoCr-OH-Si45) y 75 °C (muestra CoCr-OH-Si75) durante 24 horas y 30 minutos, respectivamente. Finalmente, las superficies CoCr-OH-Si45 y CoCr-OH-Si75 fueron sumergidas en suspensión acuosa de 4 g/L GO a 60 °C durante 12 y 24 horas obteniendo las superficies CoCr-OH-Si45-GO12h, CoCr-OH-Si75-GO12h y CoCr-OH-Si45-GO24h, y CoCr-OH-Si75-GO24h. Este conjunto de datos incluye los resultados de los datos de impedancia electroquímica obtenidos para cada superficie de CoCr (CoCr, CoCr-OH, CoCr-OHSi45, CoCr-OH-Si75 CoCr-OH-Si45-GO12h, CoCr-OH-Si75-GO12h y CoCr-OH-Si45-GO24h, y CoCr-OH-Si75-GO24h sumergidas en una solución de 3 g/L ácido hialurónico durante 7 días. more...
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- 2024
Catalog
3. Maintenance treatment with interferon alpha-2b in multiple myeloma: a prospective randomized study from PETHEMA (Program for the Study and Treatment of Hematological Malignancies, Spanish Society of Hematology)
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Bladé, J, Miguel, JF San, Escudero, ML, Fontanillas, M, Besalduch, J, Gardella, S, Arias, J, García-Conde, J, Carnero, M, Marti, JM, Rozman, C, Estapé, J, and Montserrat, E
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- 1998
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4. Quantitative Measurement of the Corrosion Rate Using a Small Counter Electrode in the Boundary of Passive and Corroded Zones of a Long Concrete Beam
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Andrade, C, primary, Macias, A, additional, Feliu, S, additional, Escudero, ML, additional, and González, JA, additional
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5. Hematological Response to Particle Debris Generated During Wear-Corrosion Processes of CoCr Surfaces Modified with Graphene Oxide and Hyaluronic Acid for Joint Prostheses.
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Escudero ML, García-Alonso MC, Chico B, Lozano RM, Sánchez-López L, Flores-Sáenz M, Cristóbal-Aguado S, Moreno-Gómez-Toledano R, and Aguado-Henche S
- Abstract
Various surface modifications to increase the lifespan of cobalt-chromium (CoCr) joint prostheses are being studied to reduce the wear rate in bone joint applications. One recently proposed modification involves depositing graphene oxide functionalized with hyaluronic acid (a compound present in joints) on CoCr surfaces, which can act as a solid lubricant. This paper analyzes the biological alterations caused by wear-corrosion phenomena that occur in joints, both from the perspective of the worn surface (in vitro model) and the particles generated during the wear processes (in vivo model). The analysis of the inflammatory response of macrophage was performed on CoCr surfaces modified with graphene oxide and functionalized with hyaluronic acid (CoCr-GO-HA), before and after wear-corrosion processes. The wear particles released during the wear-corrosion tests of the CoCr-GO-HA/CoCr ball pair immersed in 3 g/L hyaluronic acid were intra-articularly injected into the experimental animals. The hematological analysis in vivo was made considering a murine model of intra-articular injection into the left knee in male adult Wistar rats, at increasing concentrations of the collected wear particles dispersed in 0.9% NaCl. Non-significant differences in the inflammatory response to unworn CoCr-GO-HA surfaces and control (polystyrene) were obtained. The wear-corrosion of the CoCr-GO-HA disk increased the inflammatory response at both 72 and 96 h of material exposure compared to the unworn CoCr-GO-HA surfaces, although the differences were not statistically significant. The pro-inflammatory response of the macrophages was reduced on the worn surfaces of the CoCr modified and functionalized with graphene oxide (GO) and hyaluronic acid (HA), compared to the worn surfaces of the unmodified CoCr. The hematological analysis and tissue reactions after intra-articular injection did not reveal pathological damage, with average hematological values recorded, although slight reductions in creatinine and protein within non-pathological ranges were found. Some traces of biomaterial particles in the knee at the highest concentration of injected particles were only found but without inflammatory signs. The results show the potential benefits of using graphene in intra-articular prostheses, which could improve the quality of life for numerous patients. more...
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- 2024
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6. Biological Responses in the Blood and Organs of Rats to Intraperitoneal Inoculation of Graphene and Graphene Oxide.
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Aguado-Henche S, Escudero ML, García-Alonso MC, Lozano-Puerto RM, and Clemente de Arriba C
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Background: The discrepancy among the in vivo results found in the literature regarding graphene's side effects led us to conduct an in vivo study with graphene., Methods: In vivo tests involving intraperitoneal inoculation of graphene and graphene oxide nanosheets in rats were carried out to assess potential changes in the blood and organs after 15 and 30 days. Graphene and graphene oxide nanosheets at a concentration of 4 mg per kilogram were suspended in an aqueous solution of 0.9% NaCl at a 1:1 proportion (graphene or graphene oxide), i.e., 1 mg/mL., Results: Optical microscopy of liver, kidney, spleen, and lung tissues revealed no visible histological changes. However, particle traces were found in the peritoneal cavity. Thirty days after inoculation, blood samples were collected for hematological analysis. The blood analysis showed changes indicating a hepatic inflammatory process. Hematological changes after 30 days consisted of alterations to the red series, including microcytosis or higher mean hemoglobin concentrations. In addition, changes in prothrombin and thromboplastin caused longer coagulation times., Conclusion: This study contributes to further clarifying the possible toxicity of graphene and its potential biomedical applications. more...
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- 2022
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7. Wettability, Corrosion Resistance, and Osteoblast Response to Reduced Graphene Oxide on CoCr Functionalized with Hyaluronic Acid.
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Chico B, Pérez-Maceda BT, San-José S, Escudero ML, García-Alonso MC, and Lozano RM
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The durability of metal-metal prostheses depends on achieving a higher degree of lubrication. The beneficial effect of hyaluronic acid (HA) on the friction and wear of both natural and artificial joints has been reported. For this purpose, graphene oxide layers have been electrochemically reduced on CoCr surfaces (CoCrErGO) and subsequently functionalized with HA (CoCrErGOHA). These layers have been evaluated from the point of view of wettability and corrosion resistance in a physiological medium containing HA. The wettability was analyzed by contact angle measurements in phosphate buffer saline-hyaluronic acid (PBS-HA) solution. The corrosion behavior of functionalized CoCr surfaces was studied with electrochemical measurements. Biocompatibility, cytotoxicity, and expression of proteins related to wound healing and repair were studied in osteoblast-like MC3T3-E1 cell cultures. All of the reported results suggest that HA-functionalized CoCr surfaces, through ErGO layers in HA-containing media, exhibit higher hydrophilicity and better corrosion resistance. Related to this increase in wettability was the increase in the expressions of vimentin and ICAM-1, which favored the growth and adhesion of osteoblasts. Therefore, it is a promising material for consideration in trauma applications, with improved properties in terms of wettability for promoting the adhesion and growth of osteoblasts, which is desirable in implanted materials used for bone repair. more...
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- 2022
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8. Electrochemically reduced graphene oxide on CoCr biomedical alloy: Characterization, macrophage biocompatibility and hemocompatibility in rats with graphene and graphene oxide.
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Escudero ML, Llorente I, Pérez-Maceda BT, José-Pinilla SS, Sánchez-López L, Lozano RM, Aguado-Henche S, de Arriba CC, Alobera-Gracia MA, and García-Alonso MC
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- Animals, Male, Mice, Oxidation-Reduction, Rats, Rats, Wistar, Chromium Alloys chemistry, Chromium Alloys pharmacology, Coated Materials, Biocompatible chemistry, Coated Materials, Biocompatible pharmacology, Electrochemical Techniques, Graphite chemistry, Graphite pharmacology, Macrophages metabolism, Materials Testing
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Electrochemically reduced graphene oxide (ErGO) films on a biomedical grade CoCr alloy have been generated and characterized in order to study their possible application for use on joint prostheses. The electrodeposition process was performed by cyclic voltammetry. The characterization of the ErGO films on CoCr alloys by XPS revealed sp2 bonding and the presence of CO and CO residual groups in the graphene network. Biocompatibility studies were performed with mouse macrophages J774A.1 cell cultures measured by the ratio between lactate dehydrogenase and mitochondrial activities. An enhancement in the biocompatibility of the CoCr with the ErGO films was obtained, a result that became more evident as exposure time increased. Macrophages on the CoCr with the ErGO were well-distributed and conserved the characteristic cell shape. In addition, vimentin expression was unaltered in comparison with the control, results that indicated an improvement in the CoCr biocompatibility with the ErGO on the material surface. The in vivo response of graphene and graphene oxide was assessed by intraperitoneal injection in wistar rats. Red blood cells are one of the primary interaction sites so hemocompatibility tests were carried out. Rats inoculated with graphene and graphene oxide showed red blood cells of smaller size with a high content in hemoglobin., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2019 Elsevier B.V. All rights reserved.) more...
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- 2020
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9. Macrophage Biocompatibility of CoCr Wear Particles Produced under Polarization in Hyaluronic Acid Aqueous Solution.
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Perez-Maceda BT, López-Fernández ME, Díaz I, Kavanaugh A, Billi F, Escudero ML, García-Alonso MC, and Lozano RM
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Macrophages are the main cells involved in inflammatory processes and in the primary response to debris derived from wear of implanted CoCr alloys. The biocompatibility of wear particles from a high carbon CoCr alloy produced under polarization in hyaluronic acid (HA) aqueous solution was evaluated in J774A.1 mouse macrophages cultures. Polarization was applied to mimic the electrical interactions observed in living tissues. Wear tests were performed in a pin-on-disk tribometer integrating an electrochemical cell in phosphate buffer solution (PBS) and in PBS supplemented with 3 g/L HA, an average concentration that is generally found in synovial fluid, used as lubricant solution. Wear particles produced in 3 g/L HA solution showed a higher biocompatibility in J774A.1 macrophages in comparison to those elicited by particles obtained in PBS. A considerable enhancement in macrophages biocompatibility in the presence of 3 g/L of HA was further observed by the application of polarization at potentials having current densities typical of injured tissues suggesting that polarization produces an effect on the surface of the metallic material that leads to the production of wear particles that seem to be macrophage-biocompatible and less cytotoxic. The results showed the convenience of considering the influence of the electric interactions in the chemical composition of debris detached from metallic surfaces under wear corrosion to get a better understanding of the biological effects caused by the wear products. more...
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- 2018
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10. Corrosion behavior of surface modifications on titanium dental implant. In situ bacteria monitoring by electrochemical techniques.
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Díaz I, Pacha-Olivenza MÁ, Tejero R, Anitua E, González-Martín ML, Escudero ML, and García-Alonso MC
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- Acid Etching, Dental, Electrochemical Techniques, Humans, Saliva, Artificial, Streptococcus mutans drug effects, Surface Properties, Bacteria chemistry, Corrosion, Dental Implants microbiology, Titanium
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The effects of surface modifications and bacteria on the corrosion behavior of titanium have been studied. Five surface modifications were analyzed: two acid etchings (op V, op N), acid etching + anodic oxidation (op NT), sandblasting + acid etching (SLA), and machined surfaces (mach). The corrosion behavior of the surface modifications was evaluated by following the standard ANSI/AAMI/ISO 10993-15:2000. Cyclic potentiodynamic and potentiostatic anodic polarization tests and ion release by ICP-OES after immersion for 7 days in 0.9% NaCl were carried out. Microbiologically induced corrosion (MIC) of low and high roughness (mach, op V) was assessed in situ by electrochemical techniques. Streptococcus mutans bacteria were resuspended in PBS at a concentration of 3 × 10
8 bacteria mL-1 and maintained at 37°C. MIC was measured through the open circuit potential, Eoc , and electrochemical impedance spectroscopy from 2 to 28 days. Potentiodynamic curves showed the typical passive behavior for all the surface modifications. The titanium ion release after immersion was below 3 ppb. In situ bacteria monitoring showed the decrease in Eoc from -0.065 (SD 0.067) Vvs. Ag/AgCl in mach and -0.115 (SD 0.084) Vvs. Ag/AgCl in op V, to -0.333 (SD 0.147) Vvs. Ag/AgCl in mach and -0.263 (SD 0.005) Vvs. Ag/AgCl in op V, after 2 and 28 days, respectively. A reduction of the oxide film resistance, especially in op V (54 MΩ cm2 and 6 MΩ cm2 , after 2 and 28 days, respectively) could be seen. Streptococcus mutans negatively affected the corrosion resistance of titanium. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 106B: 997-1009, 2018., (© 2017 Wiley Periodicals, Inc.) more...- Published
- 2018
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11. Study of overall and local electrochemical responses of oxide films grown on CoCr alloy under biological environments.
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Diaz I, Martinez-Lerma JF, Montoya R, Llorente I, Escudero ML, and García-Alonso MC
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- Biocompatible Materials chemistry, Chromium Alloys chemistry, Cobalt chemistry, Corrosion, Dielectric Spectroscopy, Hyaluronic Acid chemistry, Materials Testing methods, Microscopy, Electron, Scanning, Oxides chemistry, Prostheses and Implants, Silver Compounds chemistry, Solutions chemistry, Surface Properties, Alloys chemistry, Electrochemistry methods
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The interaction of the physiological medium and living tissues with the implant surfaces in biological environments is regulated by biopotentials that induce changes in the chemical composition, structure and thickness of the oxide film. In this work, oxide films grown on CoCr alloys at 0.5 V vs Ag/AgCl and 0.7 V vs Ag/AgCl have been characterized through overall and localized electrochemical techniques in a phosphate buffer solution and 0.3% hyaluronic acid. Nanopores of 10-50nm diameter are homogeneously distributed along the surface in the oxide film formed at 0.7 V vs Ag/AgCl. The distribution of the Constant Phase Element studied by local electrochemical impedance spectroscopy showed a three-dimensional (3D) model on the oxide films grown at 0.5 V vs Ag/AgCl and 0.7 V vs Ag/AgCl. This behaviour is especially noticeable in oxide films grown at 0.7 V vs Ag/AgCl, probably due to surface inhomogeneities, and resistive properties generated by the potentiostatic growth of the oxide film., (Copyright © 2017 Elsevier B.V. All rights reserved.) more...
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- 2017
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12. Osseointegration of TI6Al4V dental implants modified by thermal oxidation in osteoporotic rabbits.
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Bodelón OG, Clemente C, Alobera MA, Aguado-Henche S, Escudero ML, and Alonso MC
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Background: In this work, the effect of the heat treatment on Ti6Al4V implants and topical administration of growth hormone to address a better osseointegration in osteoporotic patients has been analysed., Methods: The osseointegration process of Ti6Al4V implants modified by oxidation treatment at 700 °C for 1 h and the influence of local administration of growth hormone (GH) in osteoporotic female rabbits after 15 and 30 days of implantation have been studied. Bone response was analysed through densitometric and histomorphometric studies. Characterization of the surface was provided by scanning electron microscopy., Results: The oxidation treatment promotes the formation of an oxide scale grown on the Ti6Al4V implants that alters the nanoroughness of the surface. Bone mineral density (BMD) increases from 0.347 ± 0.014 (commercial) to 0.383 ± 0.012 g cm-2 (modified), and bone-to-implant contact (BIC) goes from 48.01 ± 14.78 (commercial) to 55.37 ± 15.31 (modified) after 30 days of implantation., Conclusions: The oxidation treatment on the Ti6Al4V dental implants enhances the early bone formation at the longest periods of implantation. No significant differences in the BMD and BIC results in healthy and osteoporotic rabbits were revealed with respect to the local administration of GH in the implantation site. more...
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- 2016
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13. Prevalence and factors associated with musculoskeletal disorders and rheumatic diseases in indigenous Maya-Yucateco people: a cross-sectional community-based study.
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Peláez-Ballestas I, Alvarez-Nemegyei J, Loyola-Sánchez A, and Escudero ML
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- Adult, Comorbidity, Cross-Sectional Studies, Disability Evaluation, Female, Humans, Logistic Models, Male, Mexico epidemiology, Middle Aged, Multivariate Analysis, Pain Measurement, Sex Factors, Surveys and Questionnaires, Indians, Central American, Musculoskeletal Pain ethnology, Rheumatic Diseases classification, Rheumatic Diseases ethnology
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This study aimed to estimate the prevalence of musculoskeletal disorders and rheumatic diseases in indigenous Maya-Yucateco communities using Community-Oriented Program for Control of Rheumatic Diseases (COPCORD) methodology. The study population comprised subjects aged ≥18 years from 11 communities in the municipality of Chankom, Yucatan. An analytical cross-sectional study was performed, and a census was used. Subjects positive for musculoskeletal (MSK) pain were examined by trained physicians. A total of 1523 community members were interviewed. The mean age was 45.2 years (standard deviation (SD) 17.9), and 917 (60.2 %) were women. Overall, 592 individuals (38.8 %; 95 % CI 36.3-41.3 %) had experienced MSK pain in the last 7 days. The pain intensity was reported as "strong" to "severe" in 43.4 %. The diagnoses were rheumatic regional pain syndromes in 165 (10.8 %; 95 % CI 9.4-12.5), low back pain in 153 (10.0 %; 95 % CI 8.5-11.6), osteoarthritis in 144 (9.4 %; 95 % CI 8.0-11.0), fibromyalgia in 35 (2.2 %; 95 % CI 1.6-3.1), rheumatoid arthritis in 17 (1.1 %; 95 % CI 0.6-1.7), undifferentiated arthritis in 8 (0.5 %; 95 % CI 0.2-0.8), and gout in 1 (0.06 %; 95 % CI 0.001-0.3). Older age, being female, disability, and physically demanding work were associated with a greater likelihood of having a rheumatic disease. In conclusion, MSK pain and rheumatic diseases were highly prevalent. The high impact of rheumatic diseases on daily activities in this indigenous population suggests the need to organize culturally-sensitive community interventions for the prevention of disabilities caused by MSK disorders and diseases. more...
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- 2016
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14. Analysis of metallic traces from the biodegradation of endomedullary AZ31 alloy temporary implants in rat organs after long implantation times.
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Bodelón OG, Iglesias C, Garrido J, Clemente C, Garcia-Alonso MC, and Escudero ML
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- Animals, Corrosion, Diffusion, Equipment Failure Analysis, Femur surgery, Longitudinal Studies, Materials Testing, Organ Specificity, Prosthesis Design, Rats, Rats, Wistar, Absorbable Implants, Alloys chemistry, Bone Substitutes chemistry, Femur chemistry, Metals analysis, Prostheses and Implants
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AZ31 alloy has been tested as a biodegradable material in the form of endomedullary implants in female Wistar rat femurs. In order to evaluate the accumulation of potentially toxic elements from the biodegradation of the implant, magnesium (Mg), aluminium (Al), zinc (Zn), manganese (Mn) and fluorine (F) levels have been measured in different organs such as kidneys, liver, lungs, spleen and brain. Several factors that may influence accumulation have been taken into account: how long the implant has been in place, whether or not the bone is fractured, and the presence of an MgF2 protective coating on the implant. The main conclusions and the clinical relevance of the study have been that AZ31 endomedullary implants have a degradation rate of about 60% after 13 months, which is fully compatible with fracture consolidation. Neither bone fracture nor an MgF2 coating seems to influence the accumulation of trace elements in the studied organs. Aluminium is the only alloying element in this study that requires special attention. The increase in Al recovered from the sampled organs represents 3.95% of the amount contained in the AZ31 implant. Al accumulates in a statistically significant way in all the organs except the brain. All of this suggests that in long-term tests AZ31 may be a suitable material for osteosynthesis. more...
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- 2015
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15. In situ electrochemical study of the interaction of cells with thermally treated titanium.
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Burgos-Asperilla L, Fierro JL, Gamero M, Escudero ML, Alonso C, and García-Alonso MC
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- Electrochemical Techniques, Humans, Microscopy, Electron, Scanning, Spectrum Analysis, Temperature, Cell Adhesion, Titanium chemistry, Titanium radiation effects
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Micromotion and fretting wear between bone and Ti-based alloys in stem and dental implants breaks the passive film and exposes the metal to the action of the complex surrounding medium, generating substantial amounts of debris and continuous Ti ion release. In this work, oxidation treatments at low temperatures (277 °C, 5 h) have been used to promote the formation of wear-corrosion resistant titanium oxide on the Ti surface. The objective of this paper has been the study of the influence of live cells on the protectiveness of the oxide formed at these low temperatures. The interaction of cells with the modified surface has been studied by scanning electron microscopy, electrochemical impedance spectroscopy, polarization curves, and x-ray photoelectron spectroscopy (XPS). The chemical composition of the thermally treated Ti surface is mainly TiO2 as anatase-rich titanium dioxide with a low concentration of hydroxyl groups and a low mean nanoroughness that could promote good cell adhesion. The electrochemical results indicate that the cells alter the overall resistance of the thermally treated Ti surfaces by decreasing the oxide resistance with time. At the same time, the anodic current increases, which is associated with cathodic control, and is probably due to the difficulty of access of oxygen to the Ti substrate. XPS reveals the presence of proteins on the surface of the treated specimens in contact with the cells and a decrease in the Ti signal associated with the extracellular matrix on the surface and the reduction of the oxide thickness. more...
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- 2015
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16. Fracture bone healing and biodegradation of AZ31 implant in rats.
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Iglesias C, Bodelón OG, Montoya R, Clemente C, Garcia-Alonso MC, Rubio JC, and Escudero ML
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- Animals, Biomechanical Phenomena, Coated Materials, Biocompatible chemistry, Corrosion, Female, Femoral Fractures diagnostic imaging, Fluorides chemistry, Fracture Fixation, Intramedullary, Magnesium Compounds chemistry, Materials Testing, Rats, Rats, Wistar, Time Factors, Tomography, X-Ray Computed, Absorbable Implants, Alloys chemistry, Biocompatible Materials chemistry, Femoral Fractures surgery, Fracture Healing
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The ideal temporary implant should offer enough mechanical support to allow healing of the fracture and then biodegrade and be resorbed by metabolic mechanisms without causing any toxic effect. The aim of this research has been to simultaneously study in situ bone healing and the biodegradation of AZ31 Mg alloy as an osteosynthesis material. The in vivo study was carried out in AZ31 implants with and without Mg-fluoride coating inserted in un-fractured and fractured femurs of Wistar rats for long experimentation time, from 1 to 13 months, by means of computed tomography, histological and histomorphometric analysis. Tomography analysis showed the bone healing and biodegradation of AZ31 implants. The fracture is healed in 100% of the animals, and AZ31 maintains its mechanical integrity throughout the healing process. Biodegradation was monitored, quantifying the evolution of gas over time by 3D composition of tomography images. In all the studied groups, gas pockets disappear with time as a result of the diffusion process through soft tissues. Histomorphometric studies reveal that after 13 months the 46.32% of AZ31 alloy has been resorbed. The resorption of the coated and uncoated AZ31 implants inserted in fractured femurs after 1, 9 and 13 months does not have statistically significant differences. There is a balance between the biodegradation of AZ31 and bone healing which allows the use of AZ31 to be proposed as an osteosynthesis material. more...
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- 2015
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17. Modeling in vivo corrosion of AZ31 as temporary biodegradable implants. Experimental validation in rats.
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Montoya R, Iglesias C, Escudero ML, and García-Alonso MC
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- Alloys therapeutic use, Animals, Corrosion, Electrolytes chemistry, Femoral Fractures diagnostic imaging, Femoral Fractures therapy, Femur diagnostic imaging, Rats, Rats, Wistar, Tomography, X-Ray Computed, Absorbable Implants veterinary, Alloys chemistry, Models, Theoretical
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In this paper, two complementary approaches, mathematical modeling and experimental results are combined to identify variables that affect the in vivo biodegradation of magnesium implants. The in vivo corrosion behavior of AZ31 alloy proposed for temporary applications as fixation of bone fractures has been modeled solving the Laplace equation by finite element method (FEM). Bar-shaped AZ31 implants of 1mm diameter and 20mm length were inserted in Wistar rat femurs with and without a fracture. The presence of gas around AZ31 implants inside the femurs has been detected in situ at the epiphysis and in fractured areas by computerized tomography (CT). Examining some in vivo conditions, the model confirms that magnesium-alloy devices have different biodegradation behavior, depending on the thickness of electrolyte at the implantation site and can be used for predicting the biodegradation behavior., (Copyright © 2014 Elsevier B.V. All rights reserved.) more...
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- 2014
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18. Response of MC3T3-E1 osteoblasts, L929 fibroblasts, and J774 macrophages to fluoride surface-modified AZ31 magnesium alloy.
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Lozano RM, Pérez-Maceda BT, Carboneras M, Onofre-Bustamante E, García-Alonso MC, and Escudero ML
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- Amino Acid Sequence, Animals, Apoptosis drug effects, Cell Cycle drug effects, Cell Line, Cell Proliferation drug effects, Cell Respiration drug effects, Cell Survival drug effects, Coated Materials, Biocompatible pharmacology, Electrophoresis, Gel, Two-Dimensional, Fibroblasts drug effects, Fibroblasts metabolism, L-Lactate Dehydrogenase metabolism, Macrophages drug effects, Macrophages metabolism, Mice, Mitochondria drug effects, Mitochondria metabolism, Molecular Sequence Data, Osteoblasts drug effects, Osteoblasts metabolism, Oxidation-Reduction drug effects, Peptides chemistry, Proteomics, Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization, Surface Properties, Alloys pharmacology, Fibroblasts cytology, Fluorides pharmacology, Macrophages cytology, Magnesium pharmacology, Osteoblasts cytology
- Abstract
The present work evaluates the biocompatibility of a fluoride surface-modified AZ31 magnesium alloy (AZ31HF) with different cell lines that coexist in the implant environment to test its potential use as a biodegradable and absorbable biomaterial for bone repair. A clear stimulation of cell proliferation and an enhancement of the mitochondrial respiratory activity were observed when mouse osteoblasts (MC3T3-E1), fibroblasts (L929), and macrophages (J774) cell lines were cultured with the modified alloy. No significant change in apoptosis or viability rates was observed when osteoblasts and fibroblasts cultures were grown in the presence of this alloy. A proteomic analysis of the MC3T3-E1 cell extracts cultured in the presence of AZ31HF showed an overexpression of proteins related with the mineralization process, which is a necessary step for bone repair. An increase in the lactate dehydrogenase activity was observed in the MC3T3-E1 and J774 cell cultures that could be a response of the oxidative stress produced by the presence of the material. This stress could be related to the increase observed in the respiratory mitochondrial activity or respiratory burst measured in theses cultures that indicate damage in the cell membranes and subsequently some cell death. Results reported here, for and against AZ31HF, should be taken into account when considering the potential use of this modified alloy in bone repair applications., (Copyright © 2013 Wiley Periodicals, Inc., a Wiley Company.) more...
- Published
- 2013
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19. Influence of the microstructure and topography on the barrier properties of oxide scales generated on blasted Ti6Al4V surfaces.
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Barranco V, Escudero ML, and García-Alonso MC
- Subjects
- Alloys, Microscopy, Electron, Scanning, Spectrum Analysis methods, Surface Properties, X-Ray Diffraction, Oxides chemistry, Titanium chemistry
- Abstract
The long-term interfacial bond between an implant and bone may be improved by creating a rough surface on the implant in order to increase the surface area available for bone/implant apposition. A natural consequence of surface roughening is an increase in metal ion release, which is itself a surface dominated process. Based on this fact, the aim of this work is to study the influence of the microstructure and topography on the barrier properties of oxide scales thermally generated at 700 °C for 1h on Ti6Al4V surfaces after blasting with Al(2)O(3) particles (coarse) or SiO(2) and ZrO(2) particles (fine). The microstructural and topographical characterization of the thermally treated blasted surfaces has been studied by means of scanning electron microscopy coupled with energy dispersive X-ray analysis, contact profilometry and X-ray diffraction. The barrier properties and corrosion behaviour of the oxide layers have been studied by means of electrochemical impedance spectroscopy (EIS) in Hank's solution. Thermal treatment at 700 °C for 1h promotes the formation of oxide scales with different morphologies and crystalline structures depending on the degree of deformation of the blasted surface. The oxide scale grown on the finely blasted sample has a pine needle-like morphology which is mainly formed of anatase TiO(2). In contrast, the oxide scale grown on the coarsely blasted sample has a globular morphology formed mainly of rutile TiO(2). The differences in morphology, i.e. fine or coarse, of the oxide scales influence the corrosion response of the blasted thermally treated samples in Hank's solution. The EIS results permit evaluation of the different oxide scales from the capacitance and resistance values obtained in the high-frequency region and show a good correlation between the morphology and barrier properties. Oxidation treatment at 700 °C for 1h of Ti6Al4V samples coarsely blasted with Al(2)O(3) improves the corrosion behaviour due to an increase in the thickness of a compact, ordered and more structurally stable oxide scale. This is due to the globular morphology of the rutile (TiO(2)) structure maintaining an average surface roughness suitable for optimal osseo-integration with long-term interfacial bonding between the implant and bone., (Copyright © 2011 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.) more...
- Published
- 2011
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20. Corrosion behaviour of AZ31 magnesium alloy with different grain sizes in simulated biological fluids.
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Alvarez-Lopez M, Pereda MD, del Valle JA, Fernandez-Lorenzo M, Garcia-Alonso MC, Ruano OA, and Escudero ML
- Subjects
- Corrosion, Electric Impedance, Electricity, Kinetics, Potentiometry, Solutions, Spectroscopy, Fourier Transform Infrared, Time Factors, Alloys chemistry, Body Fluids chemistry, Magnesium chemistry, Particle Size
- Abstract
The corrosion behaviour of AZ31 magnesium alloy with different grain sizes immersed in simulated body fluids was compared in chloride solution (8 gl(-1)) and in phosphate-buffer solution (PBS). The influence of immersion time was also analyzed. Electrochemical techniques such as open circuit potential, polarization curves, transient currents and electrochemical impedance spectroscopy, complemented with scanning electron microscopy and energy dispersive spectroscopy, were used. Immediately after the immersion in the corrosive media the corrosion resistance was similar for both grain sizes of the AZ31 alloy and higher in NaCl solutions than in PBS. However, this corrosion behaviour was reversed after longer periods of immersion due to the stabilizing of the corrosion products of MgO by P-containing compounds. These P-compounds contribute to a higher level of protection by hindering the aggressive action of chloride ions. The best corrosion behaviour of the AZ31 alloy was obtained for the finest grain alloy associated with the highest transfer resistance value, after long periods of immersion in PBS., (Copyright (c) 2009 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.) more...
- Published
- 2010
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21. Study of the interaction of inorganic and organic compounds of cell culture medium with a Ti surface.
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Burgos-Asperilla L, García-Alonso MC, Escudero ML, and Alonso C
- Subjects
- Culture Media, Electrochemistry, Microscopy, Electron, Scanning, X-Rays, Inorganic Chemicals chemistry, Organic Chemicals chemistry, Spectrum Analysis methods, Titanium
- Abstract
The interaction between Ti and each component of Dulbecco's modified Eagle's medium was studied in depth using different techniques, such as the measurement of the corrosion potential, electrochemical impedance spectroscopy and polarization curves. The characterization of metal surfaces was carried out by scanning electron microscopy and X-ray photoelectron spectroscopy (XPS). The adsorption process of each component was studied using the quartz crystal balance (QCM). The QCM and XPS results reveal that the adsorption kinetics for phosphate and calcium ions is slow. However, the bovine serum albumin (BSA) totally covers the Ti surface rapidly. Because the passive film (titanium oxide) has acidic hydroxyl groups, the calcium ions would have a bridging effect on the electrostatic adsorption of phosphate ions as well as that of BSA. The polarization curves reveal that the adsorbed glucose permits the ionic diffusion of the oxygen to the electrode, while the BSA and fetal bovine serum (FBS) adsorbed after 7 days of immersion act as a diffusive barrier. The impedance measurement and data fitting to the electrical equivalent circuit model show that the resistance of the proteins/TiO(2) interface, for Ti immersed in FBS, is higher than those obtained for BSA, due to the proteins present in the solution as well as the fact that the adsorbed proteins on the surface are greater. more...
- Published
- 2010
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22. In situ cell culture monitoring on a Ti-6Al-4V surface by electrochemical techniques.
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García-Alonso MC, Saldaña L, Alonso C, Barranco V, Muñoz-Morris MA, and Escudero ML
- Subjects
- Cell Line, Tumor, Humans, Microscopy, Electron, Scanning, Aluminum chemistry, Cell Culture Techniques methods, Electrochemical Techniques instrumentation, Electrochemical Techniques methods, Titanium chemistry, Vanadium chemistry
- Abstract
In this work, the in situ interaction between Ti-6Al-4V alloy and osteoblastic cells has been studied by electrochemical techniques as a function of time. The interaction has been monitored for cell adhesion and growth of human osteoblastic Saos-2 cells on Ti-6Al-4V samples. The study has been carried out by electrochemical techniques, e.g., studying the evolution of corrosion potential with exposure time and by electrochemical impedance spectroscopy. The impedance results have been analyzed by using different equivalent circuit models that simulate the interface state at each testing time. The adhesion of the osteoblastic cells on the Ti-6Al-4V alloy leads to surface areas with different cell coverage rates, thus showing the different responses in the impedance diagrams with time. The effect of the cells on the electrochemical response of Ti-6Al-4V alloy is clearly seen after 4 days of testing, in which two isolated and well-differentiated time constants are clearly observed. One of these is associated with the presence of the cells and the other with a passive film on the Ti-6Al-4V alloy. After 7 days of culture, the system is governed by a resistive component over a wide frequency range which is associated with an increase in the cell coverage rate on the surface due to the extracellular matrix. more...
- Published
- 2009
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23. Determination of metallic traces in kidneys, livers, lungs and spleens of rats with metallic implants after a long implantation time.
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Rubio JC, Garcia-Alonso MC, Alonso C, Alobera MA, Clemente C, Munuera L, and Escudero ML
- Subjects
- Aluminum analysis, Animals, Chromium analysis, Cobalt analysis, Mass Spectrometry methods, Metals analysis, Metals chemistry, Rats, Rats, Wistar, Titanium analysis, Kidney metabolism, Liver metabolism, Lung metabolism, Prostheses and Implants, Spleen metabolism, Trace Elements analysis
- Abstract
Metallic transfer from implants does not stop at surrounding tissues, and metallic elements may be transferred by proteins to become lodged in organs far from the implant. This work presents an in vivo study of metallic implant corrosion to measure metallic element accumulation in organs located far from the implant, such as kidneys, livers, lungs and spleens. The studied metallic implant materials were CoCr alloy, Ti, and the experimental alloy MA956 coated with alpha-alumina. The implants were inserted in the hind legs of Wistar rats. Analysis for Co, Cr, Ti and Al metallic traces was performed after a long exposure time of 12 months by Inductively Coupled Plasma (ICP) with Mass Spectrometry (MS). According to the results, the highest Cr and Ti concentrations were detected in spleens. Co is mainly found in kidneys, since this element is eliminated via urine. Cr and Ti traces increased significantly in rat organs after the long implantation time. The organs of rats implanted with the alpha-alumina coated experimental MA956 did not present any variation in Al content after 12 months, which means there was no degradation of the alumina layer surface. more...
- Published
- 2008
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24. Concentration-dependent effects of titanium and aluminium ions released from thermally oxidized Ti6Al4V alloy on human osteoblasts.
- Author
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Saldaña L, Barranco V, García-Alonso MC, Vallés G, Escudero ML, Munuera L, and Vilaboa N
- Subjects
- Aged, Alloys, Aluminum chemistry, Animals, Biocompatible Materials chemistry, Biocompatible Materials metabolism, Biomarkers metabolism, Cell Differentiation, Cell Proliferation, Cells, Cultured, Humans, Ions chemistry, Ions metabolism, Materials Testing, Osteoblasts cytology, Solutions chemistry, Titanium chemistry, Aluminum metabolism, Osteoblasts metabolism, Titanium metabolism
- Abstract
Thermal oxidation treatments of Ti6Al4V, at 500 and 700 degrees C, for 1 h result in the formation of an outer "ceramic" layer of rutile, which enhances osteoblast response. In the present study, we have measured in vitro Ti and Al ion release from Ti64 alloy in the as-received state and after thermal oxidation treatments at 500 or 700 degrees C, to culture medium under standard cell-culture conditions. Concentrations of both Ti and Al released from both thermal oxidation treatments were lower than from polished alloy. Al was released from the treated or untreated surfaces in substantially lower extent than Ti. Titanium and aluminium ions affected primary human osteoblast proliferation, metabolic activity, and differentiation in a dose-dependent manner. Treatments with individual Ti or Al metal ions in similar concentration ranges than released from the surfaces did not alter osteoblast response, which also remained unaffected after treatments with combinations of Ti plus Al applied in the proportional relations than detected in ion-release experiments. We then selected higher concentrations of Ti that impaired osteoblast proliferation and differentiation, while the proportional lower concentrations of Al did not alter osteoblast behavior. In spite of its inert character, it was found that Al significantly enhanced the deleterious effect of Ti on osteoblast differentiation. Therefore, thermal oxidation treatments of Ti6Al4V alloy may improve the biocompatibility of the alloy by reducing both Ti and Al release, and thus attenuating ion-mediated interference with osteoblast differentiation., (Copyright (c) 2005 Wiley Periodicals, Inc.) more...
- Published
- 2006
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25. A surface modified ODS superalloy by thermal oxidation for potential implant applications.
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García-Alonso MC, González-Carrasco JL, Pérez P, Haanappel VA, Escudero ML, Chao J, and Stroosnijder MF
- Abstract
In the present work attention is paid on the composition, structure and protective properties of alumina layer produced by high temperature oxidation on MA 956 superalloy (Fe-20Cr-4.5Al-0.5Ti-0.5Y(2)O(3) (wt %)). The combination of good mechanical properties of this material and the excellent biocompatibility, the good wear and corrosion behavior of an outer alpha-alumina layer, limiting the release of ionic species and wear debris from the bulk material into the body-fluid environment, can make this material a candidate alloy for medical applications. Isothermal oxidation at 1100 degrees C in air of the alloy has led to the formation of a fine-grained, compact and adherent alpha-alumina scale. Oxide nodules rich in Ti, Y, Cr, and Fe were found on the top of the surface. In vitro electrochemical corrosion experiments showed good protective properties of the oxide scale. Moreover, no spallation of the alumina layer was observed. This feature is significant considering that the alumina layer has to withstand very high compressive stresses resulting from both growth and thermal stresses incorporated during cooling., (Copyright 2001 Kluwer Academic Publishers) more...
- Published
- 2001
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26. Influence of particle size in the effect of polyethylene on human osteoblastic cells.
- Author
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Rodrigo AM, Martínez ME, Escudero ML, Ruíz J, Martínez P, Saldaña L, Gómez-García L, Fernández L, Cordero J, and Munuera L
- Subjects
- Alkaline Phosphatase metabolism, Biocompatible Materials chemistry, Calcitriol pharmacology, Cells, Cultured, Culture Media, Conditioned, Foreign-Body Reaction etiology, Gene Expression drug effects, Humans, Materials Testing, Microscopy, Electron, Scanning, Osteoblasts cytology, Osteocalcin genetics, Osteocalcin metabolism, Particle Size, Peptide Fragments metabolism, Polyethylene chemistry, Procollagen metabolism, Prosthesis Failure, RNA, Messenger genetics, RNA, Messenger metabolism, Biocompatible Materials toxicity, Osteoblasts drug effects, Osteoblasts physiology, Polyethylene toxicity
- Abstract
The influence of two different sizes of polyethylene particles (< 30 and 20-200 microm) on osteoblastic function has been studied in primary human bone cell cultures. Cells were obtained from trabecular bone fragments of patients undergoing knee reconstructive surgery. On reaching confluency, cells were subcultured in three flasks: < 30 microm polyethylene particles were added to the first flask, 20-200 microm particles to the second flask and none to the third flask, which was the control. The resulting subcultures were incubated until confluence. Osteoblastic function was evaluated by assaying the secretion of osteocalcin, alkaline phosphatase, and C-terminal type I procollagen (PICP), with or without 1.25(OH)2D3 stimulation in the cell-conditioned medium. Adding < 30 microm polyethylene particles to these osteoblastic cell cultures increased the levels of osteocalcin secreted after 1,25(OH)2D3 stimulation. Treating stimulated or basal osteoblastic cultures with either polyethylene particle size did not affect alkaline phosphatase secretion. However, the addition of <30 microm polyethylene particles decreased PICP levels in the basal and stimulated cultures. A parallel series of osteoblastic cultures was treated with < 30 microm polyethylene particles and stimulated or not with 1,25(OH)2D3 to determine the effect on osteocalcin mRNA expression using RT-PCR amplification. Polyethylene particle-treated cultures had higher osteocalcin mRNA expression regardless of whether they had been stimulated with 1,25(OH)2D3 or not. We conclude that particle size affects the influence of polyethylene on osteoblastic function markers. Particles with a diameter of less than 30 microm increase osteocalcin expression and secretion. more...
- Published
- 2001
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27. Increased conventional chemotherapy does not improve survival in multiple myeloma: long-term results of two PETHEMA trials including 914 patients.
- Author
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Bladé J, San Miguel JF, Fontanillas M, Esteve J, Maldonado J, Alcalá A, Brunet S, García-Conde J, Besalduch J, Moro MJ, Fernández-Calvo J, Conde E, Font L, Gardella S, Carnero M, Carbonell F, Martí JM, Hernández-Martín J, Ortega F, Besses C, Ribera JM, Trujillo J, Escudero ML, Rozman C, Estapé J, and Montserrat E more...
- Subjects
- Antineoplastic Combined Chemotherapy Protocols administration & dosage, Antineoplastic Combined Chemotherapy Protocols toxicity, Carmustine administration & dosage, Cause of Death, Cyclophosphamide administration & dosage, Dose-Response Relationship, Drug, Doxorubicin administration & dosage, Female, Follow-Up Studies, Humans, Male, Melphalan administration & dosage, Middle Aged, Multiple Myeloma complications, Prednisone administration & dosage, Remission Induction, Survival Analysis, Survival Rate, Vincristine administration & dosage, Antineoplastic Combined Chemotherapy Protocols therapeutic use, Multiple Myeloma drug therapy, Multiple Myeloma mortality
- Abstract
Background: Melphalan and prednisone (MP) has been the standard treatment for multiple myeloma (MM) for the last 30 years. Combination chemotherapy at conventional doses has not shown a significant prolongation of survival when compared to MP. There are few data comparing conventional chemotherapy at standard doses with conventional treatment at higher doses. We present the long-term outcome of 914 patients from two randomized trials comparing three different dose intensity regimens., Methods: From 1 January, 1985 to 31 December, 1989, 487 patients were randomized between MP (melphalan 9 mg/m(2) p.o. and prednisone 60 mg/m(2) days 1-4) and alternating VCMP (vincristine 1 mg i.v. on day 1, cyclophosphamide 500 mg/m(2) i.v. on day 1, melphalan 6 mg/m(2) p.o. on days 1-4, and prednisone 60 mg/m(2) on days 1-4) and VBAP (vincristine 1 mg i.v. on day 1, BCNU and doxorubicin 30 mg/m(2) i.v. each on day 1, and prednisone 60 mg/m(2) on days 1-4). From 1 January, 1990 to 31 May, 1994, 427 patients were randomized between VCMP/VBAP at the above detailed doses (VCMP/VBAP 'SD') and the same regimen increasing the doses of cyclophosphamide and doxorubicin from 500 to 1200 mg/m(2) and from 30 to 50 mg/m(2), respectively (VCMP/VBAP 'HD')., Results: Increasing dose intensity produced a significantly higher partial response rate (31% vs 45% vs 51% for MP, VCMP/VBAP 'SD', and VCMP/VBAP 'HD', respectively; P < 0.01). However, a significantly early death rate was observed in the HD arm (7.7, 7.5 and 12.1% for MP, VCMP/VBAP 'SD', and VCMP/VBAP 'HD', respectively; P = 0.05). Median duration of response (20 vs 18 vs 19 months for MP, VCMP/VBAP 'SD', and VCMP/VBAP 'HD', respectively; P = NS) and median survival (25 vs 31 vs 29 months for MP, VCMP/VBAP 'SD', and VCMP/VBAP 'HD', respectively; P = NS) were similar in the three groups. MP produced a higher degree of thrombocytopenia than combination chemotherapy at standard (P = 0.002) or high dose (P = 0.01), this leading to a significantly higher dose reduction in the MP arm (P < 0.001 and P = 0.003 for VCMP/VBAP 'SD' and VCMP/VBAP 'HD', respectively)., Conclusion: In these trials the response rate significantly correlated with the regimen intensity. However, no significant differences in response duration and survival were found. This highlights the limited role of conventional chemotherapy in MM and the need for further trials, aimed at determining the impact of new treatment approaches such as high-dose therapy/autotransplantation. more...
- Published
- 2001
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28. Effects of MA 956 superalloy and alpha-alumina particles on some markers of human osteoblastic cells in primary culture.
- Author
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Rodrigo AM, Martínez ME, Martínez P, Escudero ML, Ruíz J, Saldaña L, Gómez-García L, Fernández L, del Valle I, and Munuera L
- Subjects
- Aged, Alkaline Phosphatase metabolism, Cells, Cultured, Ceramics pharmacology, Culture Media, Conditioned, Humans, Materials Testing, Osteocalcin metabolism, Particle Size, Procollagen metabolism, Alloys pharmacology, Aluminum pharmacology, Aluminum Oxide pharmacology, Biocompatible Materials, Chromium pharmacology, Iron pharmacology, Osteoblasts drug effects, Titanium pharmacology, Yttrium pharmacology
- Abstract
One of the problems associated with the modern biomaterials used in prostheses is osteolysis, which, although its exact origin is unknown, has been associated with wear particles. Osteoblasts seem to participate directly in this phenomenon. This paper investigates in vitro cellular response to the wear particles from the metal substrate and ceramic covering (alpha-alumina) of a new titanium yttrium aluminum alloy, MA 956, that has been proposed as a biomaterial because of its exceptional mechanical and electrochemical properties. The effect of different sizes (10 and 80 microm) of MA 956 and alpha-alumina particles on osteoblast function was studied in primary human bone cell cultures. Cells were harvested from trabecular bone fragments obtained during knee arthroplasty. Osteoblastic cell response to the particles was measured by assaying C-terminal type I procollagen (PICP), alkaline phosphatase, and osteocalcin secretion, with and without 1.25(OH)(2)D(3) stimulation, in the cell-conditioned medium. Both sizes of MA 956 and alpha-alumina particles decreased PICP secretion in nonstimulated osteoblastic cells, but this secretion was not affected in the cultures stimulated with 1.25(OH)(2)D(3). Only the 10 microm alpha-alumina particles inhibited alkaline phosphatase activity in 1.25(OH)(2)D(3)-stimulated and nonstimulated cultures. The rise in osteocalcin levels after 1.25(OH)(2)D(3) stimulation was lower in the presence of the 10 microm MA 956 particles than in the presence of alpha-alumina particles. Although both materials seem to have directly affected in vitro osteoblastic cell function, the increase in osteocalcin levels after 1.25(OH)(2)D(3) stimulation was lower after exposure to MA 956 particles than the increase observed after exposure to alpha-alumina particles. Therefore, it does not seem that osteocalcin stimulated bone resorption, suggesting that MA 956 would be less likely to provoke osteolysis., (Copyright 2000 John Wiley & Sons, Inc.) more...
- Published
- 2001
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29. Effect of substrate roughness on the corrosion behaviour of the Al2O3/MA 956 system.
- Author
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García-Alonso MC, Escudero ML, González-Carrasco JL, and Chao J
- Subjects
- Corrosion, Electric Conductivity, Electric Impedance, Hot Temperature, Microscopy, Electron, Scanning, Oxidation-Reduction, Surface Properties, Alloys chemistry, Aluminum chemistry, Aluminum Oxide chemistry, Biocompatible Materials chemistry, Chromium chemistry, Coated Materials, Biocompatible chemistry, Iron chemistry, Titanium chemistry, Yttrium chemistry
- Abstract
This paper presents the influence of substrate roughness on the corrosion behaviour of the Al2O3/MA 956 system. An alumina layer of thickness 1-5 microm was generated of the MA956 alloy by thermal oxidation at 1100 degrees C using different exposure times. This Al2O3/MA 956 system with a polished substrate has shown excellent corrosion behaviour in a physiological fluid, due to the fact that the alpha-Al2O3 layer formed is dense, continuous and firmly adhered to the substrate, irrespective of the scale thickness. This good adherence allows it to withstand potentials above 1.7 V. Specimens with rough finish substrate and treatment times above 10 h present spallation of the alumina layer at the crests of the roughness profile. In this case a mixed corrosion behaviour between an alumina coated material and one with a passive layer is observed. In both types of specimens, rough and smooth, once the passivation layer is broken the repassivation capacity of the substrate is ensured due to the high chromium content of the alloy, under oxygenation conditions. more...
- Published
- 2000
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30. Optimal conditions for alumina coating formation on the MA956 superalloy for prosthetic bearing applications.
- Author
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Ruiz J, Escudero ML, Canahua H, and García-Alonso MC
- Subjects
- Corrosion, Electron Probe Microanalysis, Microscopy, Electron, Scanning, Surface Properties, Temperature, Time Factors, X-Ray Diffraction, Alloys, Aluminum, Aluminum Oxide, Chromium, Coated Materials, Biocompatible, Iron, Titanium, Yttrium
- Abstract
An experimental study of the oxidation treatment at high temperature of the ODS MA956 superalloy was conducted in an attempt to achieve a protective alumina scale for biomedical applications. A quadratic response-surface model was developed in order to study the effects of treatment time and temperature (in the range of 1000 degrees C to 1250 degrees C) on scale thickness. The obtained model adequately represents the experimental response and shows that the thickness gradients of the layer increase with the temperature for each exposure time and decrease steadily to zero as the treatment time increases. The microstructural characterization reveals that the alumina scale formed at or above 1000 degrees C consists of an alpha-alumina phase. Treatments at temperatures above 1150 degrees C give rise to an alumina scale with some defect probability. An increase in the temperature up to 1200 degrees C gives rise to the appearance of some blistering of the superficial scale. An oxidation treatment of 100 h at 1100 degrees C was found to be the best for guaranteeing the formation of a defect-free, compact, adherent, and continuous alpha-alumina scale thick enough to support satisfactory wear and biological conditions. more...
- Published
- 1999
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31. Comparative study of the corrosion behavior of MA-956 and conventional metallic biomaterials.
- Author
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Escudero ML, López MF, Ruiz J, García-Alonso MC, and Canahua H
- Subjects
- Corrosion, Electrochemistry, Hydrogen-Ion Concentration, Oxidation-Reduction, Surface Properties, Time Factors, Alloys chemistry, Aluminum chemistry, Biocompatible Materials chemistry, Chromium chemistry, Iron chemistry, Titanium chemistry, Yttrium chemistry
- Abstract
In this work the corrosion behavior of a new biomaterial, the MA-956 superalloy, immersed in Hank's solution is evaluated. A comparison with conventional metallic alloys used as articular implants is established. To determine the corrosion behavior we employed electrochemical methods: evaluation of corrosion potential Ecorr, electrochemical impedance spectroscopy (EIS), and anodic polarization curves. The corrosion resistance of the MA-956 superalloy preoxidized at 1100 degrees C during 100 h is at least two orders of magnitude higher than for the other alloys. This satisfactory behavior is stationary with time. Also the probability of the appearance of the pitting corrosion process is very low. When cracking is generated in the alpha-alumina layer the repassivation process is assured because of the high Cr content in the superalloy. This study is the first step in proposing this new alloy as a biomaterial. The low toxicity of these metallic alloys in the physiological environment suggests that in vivo their biocompatibility could be satisfactory. more...
- Published
- 1996
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32. Survival of multiple myeloma patients who are potential candidates for early high-dose therapy intensification/ autotransplantation and who were conventionally treated.
- Author
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Bladé J, San Miguel JF, Fontanillas M, Alcalá A, Maldonado J, García-Conde J, Conde E, Conzález-Brito G, Moro MJ, Escudero ML, Trujillo J, Pascual A, Rozman C, Estapé J, and Montserrat E
- Subjects
- Adult, Combined Modality Therapy, Cyclophosphamide administration & dosage, Female, Humans, Male, Melphalan administration & dosage, Middle Aged, Multiple Myeloma mortality, Prednisone administration & dosage, Prospective Studies, Survival Rate, Transplantation, Autologous, Vincristine administration & dosage, Antineoplastic Combined Chemotherapy Protocols therapeutic use, Bone Marrow Transplantation, Hematopoietic Stem Cell Transplantation, Multiple Myeloma therapy
- Abstract
Purpose: To analyze the outcome of patients with multiple myeloma (MM) who were potential candidates for early high-dose therapy (HDT) intensification followed by autotransplantation from a series treated with conventional chemotherapy., Patients and Methods: From January 1985 through December 1989, 487 patients with symptomatic MM were entered onto a randomized study to compare melphalan and prednisone (MP) versus vincristine, cyclophosphamide, melphalan, and prednisone (VCMP) /vincristine, carmustine (BCNU), doxorubicin, and prednisone (VBAP). The sub-group of 77 patients who could have been candidates for early intensification with HDT followed by stem-cell support (ie, < 65 years of age, stage II or III disease, performance status < 3, and objective or partial response to initial chemotherapy) are the subjects of this report., Results: Seventy-seven of 487 patients could have been candidates for early intensification. The median age was 56 years (range, 27 to 64). At diagnosis, 12% had abnormal renal function, 16% hypercalcemia, and 42% serum beta 2-microglobulin level > or = 6 mg/L; 62% had stage III disease at diagnosis. Thirty-six patients were initially treated with MP and 41 with VCMP/VBAP. The median response duration to initial chemotherapy was 22 months, and the actuarial probability of being in continued first response at 5 years was 14%. After a median follow-up time of 58 months, 59 patients have died, one was lost to follow-up evaluation, and 17 are still alive 69 to 119 months after initial chemotherapy. The median survival time from initiation of treatment was 60 months and from the time when autotransplantation would be considered, 52 months. The only independent prognostic parameter for survival was renal function at diagnosis., Conclusion: The median survival time of patients with MM who are less than 65 years of age and who respond to initial chemotherapy is 5 years. This survival duration is similar to that reported in selected series of patients given early HDT and stresses the importance of ongoing randomized trials to determine the role of HDT in the treatment of younger myeloma patients. more...
- Published
- 1996
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33. Electrochemical impedance spectroscopy of preoxidized MA 956 superalloy during in vitro experiments.
- Author
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Escudero ML, González-Carrasco JL, García-Alonso C, and Ramírez E
- Subjects
- Alloys chemistry, Aluminum Oxide chemistry, Electric Impedance, Electrochemistry methods, Heating, Oxidation-Reduction, Spectrum Analysis methods, Aluminum chemistry, Biocompatible Materials chemistry, Chromium chemistry, Iron chemistry, Titanium chemistry, Yttrium chemistry
- Abstract
Preoxidation treatment of MA 956 superalloy at 1100 degrees C produces a fine and tightly adherent alpha-alumina layer at the surface, which provides the alloy with an excellent barrier against a great variety of aggressive environments. In this work the protective capacity of the alumina/alloy system is evaluated in a physiological medium by means of electrochemical impedance spectroscopy. The electrochemical response of the material is modelled by equivalent circuits which provide the most relevant corrosion and protection parameters applicable to MA 956 in both preoxidized and as-received conditions (passivated state). The high protective capacity of preoxidized MA 956 superalloy holds for long-term tests, which indicates that the corrosion phenomena, if any, would be characterized by very slow kinetics. The corrosion resistance of the preoxidized material is at least two orders of magnitude higher than that of the non-treated alloy. more...
- Published
- 1995
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34. In vitro corrosion behaviour of MA 956 superalloy.
- Author
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Escudero ML and González-Carrasco JL
- Subjects
- Alloys chemistry, Aluminum chemistry, Biocompatible Materials chemistry, Chromium chemistry, Corrosion, Electrochemistry, Electron Probe Microanalysis, In Vitro Techniques, Iron chemistry, Oxidation-Reduction, Oxides chemistry, Prostheses and Implants adverse effects, Titanium chemistry, Yttrium chemistry, Alloys adverse effects, Aluminum adverse effects, Biocompatible Materials adverse effects, Chromium adverse effects, Iron adverse effects, Titanium adverse effects, Yttrium adverse effects
- Abstract
The need for appropriated metallic materials for long-term implants is nowadays the driving force for the development of alternative materials with improved corrosion resistance in body fluids. In this work the in vitro corrosion behaviour of MA 956 is evaluated by means of electrochemical techniques during long-term tests in simulated human body media. This alloy, after an isothermal treatment at 1100 degrees C, develops on the surface a fine, dense and adherent alpha-alumina scale which considerably enhances the good corrosion resistance of the non-treated alloy. more...
- Published
- 1994
- Full Text
- View/download PDF
35. In vivo measurement of electrical parameters with alumina-covered stainless steel electrodes.
- Author
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Escudero ML, Ruiz J, González JA, and Ruiz J
- Subjects
- Aluminum Oxide, Animals, Biocompatible Materials, Corrosion, Dogs, Electrochemistry, Electronics, Medical, In Vitro Techniques, Stainless Steel, Electrodes, Implanted
- Abstract
An experimental method has been developed for in vivo measurement of electrical parameters. It is thus possible to evaluate not only the instantaneous corrosion rate of implants but also their susceptibility to pitting corrosion. It has also been shown that when the method is applied to stainless steel/ceramic electrodes, these remain in the passive condition. If an eventual breakdown of the passivating film occurs, it will quickly regenerate itself. more...
- Published
- 1986
- Full Text
- View/download PDF
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