Mechanical properties and in vitro biological response to porous titanium alloys prepared for use in intervertebral implants.

The generation of titanium foams is a promising strategy for modifying the mechanical properties of intervertebral reinforcements. Thus, the aim of this study was to compare the in vitro biological response of Ti6Al4V alloys with different pore sizes for use in intervertebral implants in terms of the adhesion, proliferation, and differentiation of pre-osteoblastic cells. We studied the production of Ti6Al4V foams by powder metallurgy and the biological responses to Ti6Al4V foams were assessed in terms of different pore interconnectivities and elastic moduli. The Ti6Al4V foams obtained had similar porosities of approximately 34%, but different pore sizes (66 µm for fine Ti6Al4V and 147 µm for coarse Ti6Al4V) due to the sizes of the microsphere used. The Ti6Al4V foams had a slightly higher Young׳s modulus compared with cancellous bone. The dynamic mechanical properties of the Ti6Al4V foams were slightly low, but these materials can satisfy the requirements for intervertebral prosthesis applications. The cultured cells colonized both sizes of microspheres near the pore spaces, where they occupied almost the entire area of the microspheres when the final cell culture time was reached. No statistical differences in cell proliferation were observed; however, the cells filled the pores on fine Ti6Al4V foams but they only colonized the superficial microspheres, whereas the cells did not fill the pores on coarse Ti6Al4V foams but they were distributed throughout most of the material. In addition, the microspheres with wide pores (coarse Ti6Al4V) stimulated higher osteoblast differentiation, as demonstrated by the Alcaline Phosphatase (ALP) activity. Our in vitro results suggest that foams with wide pore facilitate internal cell colonization and stimulate osteoblast differentiation.

Revascularización carotídea con stent: implicaciones clínicas y para el procedimiento de la presencia de una lesión suboclusiva / Carotid artery stenting: clinical and procedural implications for near-occlusion stenosis

Introducción y objetivos: La conveniencia del implante de stent en lesiones carotídeas suboclusivas es un tema controvertido. Nuestro trabajo valoró las implicaciones clínicas y de procedimiento de la revascularización de lesiones carotídeas suboclusivas. Métodos: Se incluyó a 205 pacientes con enfermedad carotídea revascularizados con stent: los pacientes con lesiones suboclusivas (n = 54) fueron comparados con el resto de la población (n = 151). Resultados: No hubo diferencias entre grupos para la edad, el sexo y la tasa de pacientes sintomáticos (que constituían 3 cuartas partes de la población). El implante de stent en lesiones suboclusivas cursó con una alta tasa de éxito (96%), similar al resto de las lesiones (98%). La revascularización de las lesiones suboclusivas condicionó un mayor uso de protección proximal (54% vs. 20,5%, p < 0,001) y necesidad de predilatación (33% vs. 17%, p = 0,01). El abordaje de lesiones suboclusivas ocasionó un mayor desprendimiento de placa, manifestado por una mayor tasa de material embólico extraído (18,5% vs. 7%, p = 0,01) y de lesiones isquémicas cerebrales periprocedimiento (47% vs. 31%, p = 0,07). A los 30 días de la revascularización, la tasa de eventos neurológicos (muerte, ictus mayor, ictus menor) mostró tendencia a ser mayor para el grupo con lesiones suboclusivas (9,2% vs. 3,2%, p = 0,08). Conclusiones: La revascularización con stent de lesiones carotídeas suboclusivas presenta una alta tasa de éxito de procedimiento; sin embargo, su mayor carga de placa ocasiona un superior porcentaje de lesiones isquémicas cerebrales, y de eventos neurovasculares en el primer mes (AU)

Introduction and objectives: The advisability of implanting a stent in carotid near-occlusion stenosis is a controversial topic. We have assessed procedural and clinical implications of stent implantation for carotid artery disease with near occlusion. Methods: We included 205 patients who underwent carotid artery revascularisation with a stent. The group of patients with near-occlusion stenosis (n=54)was compared to the rest of the population (n=151). Results: No differences were found between groups for age, sex, and the percentage of symptomatic patients (three-quarters of the population). Carotid stent revascularisation for near-occlusion stenosis presented a high procedural success rate (96%) similar to that of revascularisation processes for other lesions (98%). Stenting in cases of near-occlusion stenosis required increased use of proximal protection (54% vs. 20.5%, P<.001) and predilation (33% vs. 17%, P=.01). The process to repair near-occlusion stenosis cause increased detachment of plaque, as shown by higher percentages of macroscopic plaque captured by protection devices (18.5% vs. 7%, P=.01) and of perioperative ischaemic brain lesions (47% vs 31%, P = .07). At 30 days of follow-up, the tendency toward adverse neurological events (death, major and minor stroke) was higher in the near-occlusion group (9.2% vs. 3.2%, P=.08). Conclusions: Stent revascularisation for near-occlusion carotid stenosis has a high procedural success rate; however, its higher plaque load was responsible for the increased rate of ischaemic brain lesions and adverse neurovascular events at 30 days post-procedure (AU)

Carotid artery stenting: clinical and procedural implications for near-occlusion stenosis.

INTRODUCTION AND OBJECTIVES: The advisability of implanting a stent in carotid near-occlusion stenosis is a controversial topic. We have assessed procedural and clinical implications of stent implantation for carotid artery disease with near occlusion. METHODS: We included 205 patients who underwent carotid artery revascularisation with a stent. The group of patients with near-occlusion stenosis (n=54)was compared to the rest of the population (n=151). RESULTS: No differences were found between groups for age, sex, and the percentage of symptomatic patients (three-quarters of the population). Carotid stent revascularisation for near-occlusion stenosis presented a high procedural success rate (96%) similar to that of revascularisation processes for other lesions (98%). Stenting in cases of near-occlusion stenosis required increased use of proximal protection (54% vs. 20.5%, P<.001) and predilation (33% vs. 17%, P=.01). The process to repair near-occlusion stenosis cause increased detachment of plaque, as shown by higher percentages of macroscopic plaque captured by protection devices (18.5% vs. 7%, P=.01) and of perioperative ischaemic brain lesions (47% vs 31%, P = .07). At 30 days of follow-up, the tendency toward adverse neurological events (death, major and minor stroke) was higher in the near-occlusion group (9.2% vs. 3.2%, P=.08). CONCLUSIONS: Stent revascularisation for near-occlusion carotid stenosis has a high procedural success rate; however, its higher plaque load was responsible for the increased rate of ischaemic brain lesions and adverse neurovascular events at 30 days post-procedure.

Improving the binding capacity of Ni2+ decorated porous magnetic silica spheres for histidine-rich protein separation.

Biomagnetic immobilization of histidine-rich proteins based on the single-step affinity adsorption of transition metal ions continues to be a suitable practice as a cost effective and a up scaled alternative to the to multiple-step chromatographic separations. In our previous work, we synthesised Porous Magnetic silica (PMS) spheres by one-step hydrothermal-assisted modified-stöber method. The obtained spheres were decorated with Ni(2+) and Co(2+), and evaluated for the capture of a H6-Tagged green fluorescence protein (GFP-H6) protein. The binding capacity of the obtained spheres was found to be slightly higher in the case Ni(2+) decorated PMS spheres (PMSNi). However, comparing with commercial products, the binding capacity was found to be lower than the expected. In this way, the present work is an attempt to improve the binding capacity of PMSNi to histidine-rich proteins. We find that increasing the amount of Ni(2+) onto the surface of the PMS spheres leads to an increment of the binding capacity to GFP-H6 by a factor of two. On the other hand, we explore how the size of histidine-rich protein can affect the binding capacity comparing the results of the GFP-6H to those of the His-tagged α-galactosidase (α-GLA). Finally, we demonstrate that the optimization of the magnetophoresis parameters during washing and eluting steps can lead to an additional improvement of the binding capacity.

Reversible aggregation and chemical resistance of magnetic nanoclusters for their recycling and repetitive use in industrial bioprocesses.

Magnetic nanoclusters are widely used as carriers for biomedical and bioindustrial applications. The chemical resistance of the nanoclusters is a key factor for the recycling the magnetic beads for a repetitive use in the industrial bioprocesses. In this work, a study of the chemical resistance of Fe2O3 silica-coated nanoclusters at different pH is presented. The use of Horizontal Low Gradient Magnetic Field (HLGMF) for the control and separation of the magnetic nanoclusters at diferent magnetic field gradients is also investigated. For these purposes Fe2O3 silica-coated nanoclusters are synthesised and characreized by SQUID, TEM, Zeta potential techniques. The magnetophoresis study was performed at 15 T/m and 30 T/m magnetic field gradients. Recycling aspects of the nanoclusters were estimated by evaluating their resistance to pH variation from acid to basic solutions of about pH 2.5 and 10.

Fabrication of poly(lactic acid)-poly(ethylene oxide) electrospun membranes with controlled micro to nanofiber sizes.

Biodegradable poly(L-lactide acid) (PLLA) nanofiber membranes were prepared by electrospinning of PLLA and poly(ethylene oxide) (PEO). The selective removal of PEO by water allows to obtain smaller fiber diameters and to increase the porosity of the membranes in comparison to PLLA membranes obtained under the same electrospinning conditions. After removal of PEO membranes with fiber sizes of 260 nm and average porosity close to 80% are obtained. Thermal and infrared results confirm the poor miscibility of PLLA and PEO, with the PEO randomly distributed along the PLLA fibers. On the other, PLLA and PEO mixing strongly affect their respective degradation temperatures. The influence of the PEO in the electrospinning process is discussed and the results are correlated to the evolution of the PLLA fiber diameter.

Design and characterization of Ni2+ and Co2+ decorated Porous Magnetic Silica spheres synthesized by hydrothermal-assisted modified-Stöber method for His-tagged proteins separation.

The complete elimination of enzymes from the reaction mixture and the possibility of its recycling for several rounds result in great benefits, allowing the reduction of the enzyme consumption and their usability in continuous processes. In this work, it is evaluated the capture of a H6-tagged green fluorescence protein (GFP-H6) on porous magnetic spheres using the Co(2+) and Ni(2+) affinity adsorption as a possible cost-effective and up-scaled alternative way for the immobilization of His-tagged proteins. For this purpose, Porous Magnetic Silica (PMS) spheres were synthesized by one-step hydrothermal-assisted modified-Stöber method. The obtained spheres have a homogenous size distribution of 400 nm diameter. The γ-Fe(2)O(3) nanoparticles are homogenously distributed in the silica matrix. The obtained PMS spheres have a saturation magnetization of about 10 emu/g. Magnetophoresis measurements show a total separation time of 16 min at 60 T/m. The obtained PMS spheres were successfully and homogenously decorated with Co(2+) and Ni(2+) and then evaluated for the capture of a GFP-H6 protein. The results were compared with the performance of the commercial beads Dynabeads® His-Tag Isolation & Pulldown.