1,329 research outputs found
Designing lentiviral vectors for gene therapy of genetic diseases
Lentiviral vectors are the most frequently used tool to stably transfer and express genes in the context of gene therapy for monogenic diseases. The vast majority of clinical applications involves an ex vivo modality whereby lentiviral vectors are used to transduce autologous somatic cells, ob-tained from patients and re-delivered to patients after transduction. Examples are hematopoietic stem cells used in gene therapy for hematological or neurometabolic diseases or T cells for immunotherapy of cancer. We review the design and use of lentiviral vectors in gene therapy of monogenic diseases, with a focus on controlling gene expression by transcriptional or post-transcriptional mechanisms in the context of vectors that have already entered a clinical development phase
Interactions between Retroviruses and the Host Cell Genome
Replication-defective retroviral vectors have been used for more than 25 years as a tool for efficient and stable insertion of therapeutic transgenes in human cells. Patients suffering from severe genetic diseases have been successfully treated by transplantation of autologous hematopoietic stem-progenitor cells (HSPCs) transduced with retroviral vectors, and the first of this class of therapies, Strimvelis, has recently received market authorization in Europe. Some clinical trials, however, resulted in severe adverse events caused by vector-induced proto-oncogene activation, which showed that retroviral vectors may retain a genotoxic potential associated to proviral integration in the human genome. The adverse events sparked a renewed interest in the biology of retroviruses, which led in a few years to a remarkable understanding of the molecular mechanisms underlying retroviral integration site selection within mammalian genomes. This review summarizes the current knowledge on retrovirus-host interactions at the genomic level, and the peculiar mechanisms by which different retroviruses, and their related gene transfer vectors, integrate in, and interact with, the human genome. This knowledge provides the basis for the development of safer and more efficacious retroviral vectors for human gene therapy
Influence of infill on the cyclic behaviour of traditional half-timbered walls
Half-timbered buildings represent an important historical heritage in many countries. They are diffused in various regions for different reasons, such as availability of materials, to lighten a structure, low cost and the strength they offer, and as a construction element able to resist seismic actions. This latter issue is the research topic analysed here, as half-timbered buildings have been specifically used in reconstruction plans as earthquake-resistant buildings
in many countries, such as Portugal, India, Greece, etc. The aim of this paper is to study the behaviour under cyclic loading of such half-timbered walls, with typical connections, materials and geometries encountered in existing buildings.
Traditionally, different types of infill could be applied to half-timbered walls depending on the country, namely brick masonry, rubble masonry, hay, mud, etc. The focus of this paper is to study and compare the seismic behaviour of the walls considering two different infill typologies, as well as the possibility of having no infill, i.e. considering only the timber frame. Cyclic test were performed on traditional walls and their behaviour was studied in terms of ultimate capacity, deformability, energy dissipation and stiffness.Fundação para a Ciência e a Tecnologia (FCT
Extremal dyonic black holes in D=4 Gauss-Bonnet gravity
We investigate extremal dyon black holes in the Einstein-Maxwell-dilaton
(EMD) theory with higher curvature corrections in the form of the Gauss-Bonnet
density coupled to the dilaton. In the same theory without the Gauss-Bonnet
term the extremal dyon solutions exist only for discrete values of the dilaton
coupling constant . We show that the Gauss-Bonnet term acts as a dyon hair
tonic enlarging the allowed values of to continuous domains in the plane
the second parameter being the magnetic charge. In the limit of the
vanishing curvature coupling (a large magnetic charge) the dyon solutions
obtained tend to the Reissner-Nordstr\"om solution but not to the extremal
dyons of the EMD theory. Both solutions have the same values of the horizon
radius as a function of charges. The entropy of new dyonic black holes
interpolates between the Bekenstein-Hawking value in the limit of the large
magnetic charge (equivalent to the vanishing Gauss-Bonnet coupling) and twice
this value for the vanishing magnetic charge. Although an expression for the
entropy can be obtained analytically using purely local near-horizon solutions,
its interpretation as the black hole entropy is legitimate only once the global
black hole solution is known to exist, and we obtain numerically the
corresponding conditions on the parameters. Thus, a purely local analysis is
insufficient to fully understand the entropy of the curvature corrected black
holes. We also find dyon solutions which are not asymptotically flat, but
approach the linear dilaton background at infinity. They describe magnetic
black holes on the electric linear dilaton background.Comment: 19 pages, 3 figures, revtex
A study on organogenic potential in the Vitis genus
In order to increase the number of grape genotypes adapted to in vitro manipulation studies, an investigation on the regenerative potentiality in the Vitis genus was conducted on cultivars of Vitis vinifera L., (Barbera, Cabernet franc, Cabernet Sauvignon, Canner Seedless bianco, Chardonnay, Enantio, Moscato bianco, Riesling, Sultana moscato bianco and Sultanina rouge), V. vinifera silvestris G., V. amurensis R., V. armata D. and G., V. riparia M., V. simpsonii M., as well as the rootstocks 110 Richter and Schwarzmann, and the interspecific variety Staufer. Regeneration was induced via direct organogenesis from young leaves, and a relevant genotypic influence on the morphogenic potentiality was observed. Among the 18 different genotypes tested, regeneration occurred with different efficiencies and precocity. Agreeable efficiencies were obtained for Sultana moscato, Riesling, Chardonnay and Cabernet franc, while Enantio and Cabernet Sauvignon were recalcitrant to shoot regeneration. V. armata was the most favourable to this regeneration system
Comparing 17-β-estradiol supply strategies for applying the XVE-Cre/loxP system in grape gene transfer (Vitis vinifera L.)
Assays for enhancing the performance of 17-β-estradiol induction in the XVE-Cre/loxP system were performed on two transgenic 'Brachetto' plants obtained with the pX6-pKcpGVA construct, which is derived from the chemical-inducible pX6 vector carrying the neomycin phosphotransferase (nptII) gene and the XVE-Cre/loxP sequence. The 17-β-estradiol supply is expected to induce Cre recombinase expression resulting in nptII gene removal. We compared different hormone supply strategies during shoot organogenesis from meristematic proliferative tissue (MPT) or from the cut surface between leaf and petiole (SOLP) or during micropropagation from bud (MB). The effectiveness of the estradiol induction was evaluated on different tissues of the regenerated plantlets by means of nptII copy number quantification with Real time PCR. Results showed that the Cre/loxP inducible system functions effectively – however with different efficiencies- in both root and leaf tissues, and that micropropagation from buds combined with constant wetting with 17-β-estradiol is the most efficient and reproducible strategy for effective in vivo hormone induction.
Fire-eater’s pneumonitis
Fire-eater’s pneumonitis, also known as ‘fireeater’s lung’, is an acute inflammatory response of the lungs to the accidental aspiration, during the show, of ‘pyrofluids’ or kerdan [1-9]. Kerdan is composed of petroleum-distilled products like toluene, xylene, ethilbenzene which differ from kerosene composition. Kerdan is characterised by its reduced viscosity and, unfortunately, by its rapid diffusion throughout the bronchial tree after sudden accidental aspiration [7]. Histological findings (not easily available in the literature) show necrotising acute bronchiolitis and necrotising acute fibrinous pneumonia, as previously reported in experimental models [10]. Despite the severe initial presentation, ‘fire-eater’s lung’ usually has a favourable evolution with ‘restitutio ad integrum’ of pulmonary functions [7]
Rotating Solution of Einstein-Maxwell Dilaton Gravity with Unusual Asymptotics
We study electrically charged, dilaton black holes, which possess
infinitesimal angular momentum in the presence of one or two Liouville type
potentials. These solutions are neither asymptotically flat nor (anti)-de
Sitter. Some properties of the solutions are discussed.Comment: 11 pages, Accepted (Int. J. Theor. Phys.
High efficiency somatic embryogenesis and plant germination in grapevine cultivars Chardonnay and Brachetto a grappolo lungo
A highly efficient, reproducible method for somatic embryogenesis induction, plant recovery and embryogenic culture preservation has been developed for cvs Chardonnay and Brachetto a grappolo lungo (Vitis vinifera), starting from immature anthers and ovaries. Embryogenic induction efficiency was 2 % and 17 % in anthers for Chardonnay and Brachetto g.l., respectively, and 14 % in ovaries for both cultivars. Embryogenic cultures of both genotypes are still propagating 3.5 years after the initial induction and are still morphogenic. Embryo conversion into plantlets occurred at suitable efficiencies during a 100 d culture for both Chardonnay (37 % and 15 %) and Brachetto g.l. (30 % and 29 %), in the two media tested. Organogenesis was also obtained from cotyledonary leaves of Chardonnay.
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