Suchergebnisse

The lack of a functional vascular supply has, to a large extent, hampered the whole range of clinical applications of 'successful' laboratory-based bone tissue engineering strategies. To the present, grafts have been dependent on post-implant vascularization, which jeopardizes graft integration and often leads to its failure. For this reason, the development of strategies that could effectively induce the establishment of a microcirculation in the engineered constructs has become a major goal for the tissue engineering research community. This review addresses the role and importance of the development of a vascular network in bone tissue engineering and provides an overview of the most up to date research efforts to develop such a network. ; M. I. Santos would like to acknowledge the Portuguese Foundation for Science and Technology (FCT) for her Ph.D. grant (SFRH/BD/13428/2003). This work was partially supported by FCT through funds from POCTI and/or FEDER programs and by the European Union funded STREP Project HIPPOCRATES (NMP3-CT-2003-505758). This work was carried out under the scope of the European NoE EXPERTISSUES (NMP3-CT-2004-500283). The authors also acknowledge Gabriela A. Silva for critically reading the ...

The reconstruction of bone defects based on cell-seeded constructs requires a functional microvasculature that meets the metabolic demands of the engineered tissue. Therefore, strategies that augment neovascularization need to be identified. We propose an in vitro strategy consisting of the simultaneous culture of osteoblasts and endothelial cells on a starch-based scaffold for the formation of pre-vascular structures, with the final aim of accelerating the establishment of a vascular bed in the implanted construct. Human dermal microvascular endothelial cells (HDMECs) were co-cultured with human osteoblasts (hOBs) on a 3D starch-based scaffold and after 21 days of culture HDMEC aligned and organized into microcapillary-like structures. These vascular-like structures evolved from a cord-like configuration to a more complex branched morphology, had a lumen and stained in the perivascular region for type IV collagen. Genetic profiling of 84 osteogenesis-related genes was performed on coculture vs. monoculture. Osteoblasts in co-culture showed a significant up-regulation of type I collagen and immunohistochemistry revealed that the scaffold was filled with a dense matrix stained for type I collagen. In direct contact with HDMEC hOBs secreted higher amounts of VEGF in relation to monoculture and the highest peak in the release profile correlated with the formation of microcapillary-like structures. The heterotypic communication between the two cell types was also assured by direct cell– cell contact as shown by the expression of the gap junction connexin 43. In summary, by making use of heterotypic cellular crosstalk this co-culture system is a strategy to form vascular-like structures in vitro on a 3D scaffold. ; M.I. Santos would like to acknowledge the Portuguese Foundation for Science and Technology (FCT) for her PhD scholarship (SFRH/BD/13428/2003). This work was partially supported by FCT through funds from POCTI and/or FEDER programs and by the European Union funded STREP Project HIPPOCRATES ...

La obtención de planta de calidad para la producción a escala comercial de bambú es un factor importante, debido a que los métodos convencionales de propagación han sido poco estudiados y limitado su propagación. El presente trabajo se desarrollo bajo condiciones de vivero, con el propósito de evaluar el efecto de los factores método de propagación (CH, V y SN), especies de bambú (Ga, Bo y Bv) y sustratos (ATC, TCE y SIC) sobre supervivencia (SPV), número de hijuelos (NH), número de raíz (NR), longitud de raíz (LR), Número de hojas por plántula (NHA), altura (AL) y diámetro del tallo (DI) del primer hijuelo de plantas de bambú, en macetas de polietileno negro. Los tratamientos se establecieron en un diseño completamente al azar con tres repeticiones. Las variables respuesta fueron evaluadas al final del experimento (136 DDT). El método por chusquin es mejor que el de vareta y segmento nodal, para las variables en estudio. La vareta y el segmento nodal ofrecen menor supervivencia y reducido número de hijuelos. Mientras que la Guadua angustifolia y Bambusa vulgaris son las mejores especies en relación a la Bambusa oldhamii para la propagación de planta de bambú, independientemente del sustrato que se utilice

Presently the majority of tissue engineering approaches aimed at regenerating bone relies only on postimplantation vascularization. Strategies that include seeding endothelial cells (ECs) on biomaterials and promoting their adhesion, migration and functionality might be a solution for the formation of vascularized bone. Nano/micro-fiber-combined scaffolds have an innovative structure, inspired by extracellular matrix (ECM) that combines a nano-network, aimed to promote cell adhesion, with a micro-fiber mesh that provides the mechanical support. In this work we addressed the influence of this nano-network on growth pattern, morphology, inflammatory expression profile, expression of structural proteins, homotypic interactions and angiogenic potential of human EC cultured on a scaffold made of a blend of starch and poly(caprolactone). The nano-network allowed cells to span between individual micro-fibers and influenced cell morphology. Furthermore, on nano-fibers as well as on micro-fibers ECs maintained the physiological expression pattern of the structural protein vimentin and PECAM-1 between adjacent cells. In addition, ECs growing on the nano/micro-fiber-combined scaffold were sensitive to pro-inflammatory stimulus. Under pro-angiogenic conditions in vitro, the ECM-like nano-network provided the structural and organizational stability for ECs' migration and organization into capillary-like structures. The architecture of nano/micro-fiber-combined scaffolds elicited and guided the 3D distribution of ECs without compromising the structural requirements for bone regeneration. ; M.I. Santos would like to acknowledge the Portuguese Foundation for Science and Technology (FCT) for her PhD scholarship (SFRH/BD/13428/2003). This work was partially supported by FCT through funds from POCTI and/or FEDER programs and by the European Union funded STREP Project HIPPOCRATES (NMP3-CT-2003-505758). This work was carried out under the scope of the European NoE EXPERTISSUES ...

In a wide range of medical fields, technological advancements have led to an increase in the average collective dose in national populations worldwide. Periodic estimations of the average collective population dose due to medical exposure is, therefore of utmost importance, and is now mandatory in countries within the European Union (article 12 of EURATOM directive 97/43). Presented in this work is a report on the estimation of the collective dose in the Portuguese population due to nuclear medicine diagnostic procedures and the Top 20 diagnostic radiology examinations, which represent the 20 exams that contribute the most to the total collective dose in diagnostic radiology and interventional procedures in Europe. This work involved the collaboration of a multidisciplinary taskforce comprising representatives of all major Portuguese stakeholders (universities, research institutions, public and private healthcare providers, administrative services of the National Healthcare System, scientific and professional associations and private service providers). This allowed us to gather a comprehensive amount of data necessary for a robust estimation of the collective effective dose to the Portuguese population. The methodology used for data collection and dose estimation was based on European Commission recommendations, as this work was performed in the framework of the European wide Dose Datamed II project. This is the first study estimating the collective dose for the population in Portugal, considering such a wide national coverage and range of procedures and consisting of important baseline reference data. The taskforce intends to continue developing periodic collective dose estimations in the future. The estimated annual average effective dose for the Portuguese population was of 0.080±0.017 mSv caput(-1) for nuclear medicine exams and of 0.96±0.68 mSv caput(-1) for the Top 20 diagnostic radiology exams. ; info:eu-repo/semantics/publishedVersion

Purpose of the studyATV/r or DRV/r plus TDF/FTC are recommended for first‐line therapy due at least in part to their clinical tolerability and scarce metabolic effects. We investigated whether both regimens might differ regarding plasma lipids, insulin resistance (HOMA‐IR), and estimated glomerular filtration rate (MDRD).MethodsMulticentre, randomized, clinical trial (ATADAR Study, NCT01274780). Primary end‐point: 24‐week change in total cholesterol. Secondary end‐points: changes in lipids other than total cholesterol, HOMA‐IR, and MDRD; clinical tolerability; and efficacy. We assumed that patients assigned to DRV/r would have an increase in plasma total cholesterol<21 mg/dL, which was the difference between lopinavir/r and ATV/r in CASTLE study. Fasting plasma lipids, glucose, insulin, and creatinine were measured at baseline, and 4, 12, and 24 weeks. Analyses were by intent‐to‐treat.Summary of results180 patients were randomized (ATV/r=91, DRV/r=89), 95% Caucasian, and 8% co‐infected with hepatitis C virus. At baseline (mean, SD): age 36 (9) years; plasma log HIV RNA 4.8 (0.7); CD4 334 (189) cells/mm3; triglycerides 107 (62), total cholesterol 158 (32), LDL cholesterol 97 (28), HDL cholesterol 39 (11) mg/dL, and glucose 84 (13) mg/dL; HOMA‐IR 2.47 (3.46); and MDRD 108 (21) mL/min/1.73 m2. At 24 weeks, total cholesterol (mean, SD) changed +7.26 (26.76) mg/dL with ATV/r and +11.47 (25.85) mg/dL with DRV/r (estimated difference ATV/r minus DRV/r −4.21 (95% CI−12.11 to +3.69), P=0.2944), thus confirming our primary hypothesis. Changes (mean, SD) in triglycerides were roughly similar: +16.29 (61.76) mg/dL with ATV/r and +18.40 (64.24) mg/dL with DRV/r (P=0.8261), but there were trends to more favourable changes in LDL (−2.14 [21.45] vs +3.14 [21.97] mg/dL, P=0.1160) and HDL cholesterol (+5.50 [10.36] vs +3.88 [8.42] mg/dL, P=0.2625), and total‐to‐HDL cholesterol ratio (−1.16 [6.38] vs −0.14 [0.86], P=0.0652) with ATV/r than with DRV/r. There were small, non‐significant decreases in HOMA‐IR (ATV/r −0.17 [2.48] vs DRV/r −0.70 [3.38], P=0.3785) and MDRD (ATV/r −7 [22] vs DRV/r −6 [15] mL/min/1.73 m2, P=0.6652). 6 ATV/r and 3 DRV/r patients had their study drugs discontinued because of adverse effects (P=0.4967). 7 additional patients in each arm had confirmed HIV RNA >50 copies.ConclusionsThere were trends to more favourable changes in LDL and HDL cholesterol and particularly total‐to‐HDL cholesterol ratio at 24 weeks with ATV/r than with DRV/r.

7‐11 November 2010, Tenth International Congress on Drug Therapy in HIV Infection, Glasgow, UK