55 research outputs found
Cell-based therapies in regenerative medicicne: the therapeutic potential of umbilical cord and dental pulp derived stem/stromal cells
O direito dos sócios à informação
A informação é o veículo que nos permite obter conhecimento acerca de determinado
assunto ou objeto. Atendendo à natureza humana, o indivíduo necessita de se manter
informado e atualizado acerca do mundo que o rodeia. A informação pode ser obtida de
diversas formas: por via eletrónica, de forma escrita, entre outras. Contudo, quando a
informação não é obtida de fonte fidedigna pode ser incompleta ou imprecisa e pode
desencadear diversos problemas ou prejuízos.
Este conceito é igualmente aplicável ao nível do direito das sociedades, uma vez que
o indivíduo que obtém a informação irá tomar decisões baseadas nessas mesmas
informações, sejam estas erradas ou não, o que pode acarretar sérias consequências. Neste
sentido, o legislador foi prudente ao criar mecanismos que pretendem auxiliar o
destinatário da informação a ter confiança na informação que lhe foi, ou deveria ter sido
prestada e quando isso não aconteça dando-lhe a possibilidade de repor o seu direito de ser
informado, exemplo desta proteção é a possibilidade de, em determinadas situações, o
sócio requerer a anulação das deliberações sociais por não terem sido prestados os
elementos mínimos de informação necessário à tomada da deliberação em causa.
Neste trabalho de investigação pretende-se analisar, para além das especificidades
inerentes à informação em geral, a informação que deve ser prestada, em particular, no
âmbito da vida societária. De facto, colocaremos a mira deste trabalho na informação a
prestar aos sócios. Para tanto, teremos de analisar, em primeira linha, quem tem direito a
ser informado e, coetaneamente, sobre quem recai o dever de informar. Analisaremos,
ainda, a forma que deve revestir a informação sem descurar naturalmente o respetivo
conteúdo. Veremos os motivos que enformam a licitude em recusar prestar informações
societárias e, bem assim, as consequências para a recusa ilícita de as prestar, dando, nesta
última sede, especial enfoque ao inquérito judicial e à impugnação de deliberações sociais
Scaffolds for Peripheral Nerve Regeneration, the Importance of In Vitro and In Vivo Studies for the Development of Cell-Based Therapies and Biomaterials: State of the Art
Human adult peripheral nerve injuries are a high incidence clinical problem that greatly affects patients’ quality of life. Although peripheral nervous system has intrinsic regenerative capacity, this occurs in an incomplete or poorly functional manner. When a nerve fiber loses its continuity with consequent damage of the basal lamina tubes, axon spontaneous regeneration is disorganized and mismatched. These phenomena translate in an inadequate nerve functional recovery and consequent musculoskeletal incapacity. Nerve grafts still remain the gold standard in peripheral injuries treatment. However, this approach contains its disadvantages such as the necessity of primary surgery to harvest the autografts, loss of a functional nerve, donor site morbidity and longer surgery procedures. Therefore, biomaterials and tissue engineering can provide efficient resources and alternatives to nerve injury repair not only by the development of biocompatible structures but also, introducing neurotrophic factors and cellular systems to stimulate optimum clinical outcome. In this chapter, a comprehensive state-of-the art picture of tissue-engineered nerve grafts scaffolds, their application in nerve regeneration along with latest advances in peripheral nerve repair and future perspectives will be discussed, including our own large experience in this field of knowledge
Metabolomic and Proteomic Analysis of the Mesenchymal Stem Cells’ Secretome
Mesenchymal stem cells (MSCs) are multipotent stromal cells with a strong potential in human regenerative medicine due to their ability to renew themselves and differentiate into various specialized cell types under certain physiological or experimental conditions. MSCs secrete a broad spectrum of autocrine and paracrine factors (MSCs’ secretome) that could exert significant effects on cells in their vicinity. MSCs have been clinically tested and have displayed a great potential in the treatment of bone/cartilage fractures and disorders, diabetes, cardiovascular diseases and immune, neurodegenerative and inflammatory diseases. The therapeutic efficacy of MSCs was initially attributed to their multipotent character and ability to engraft and differentiate at the site of injury. However, in recent years, it has been revealed that either undifferentiated or differentiated MSCs’ secretome plays an important role in the therapeutic potential of MSCs. The deciphering of the composition of MSCs’ secretome through proteomic and metabolic analyses and implementation of certain advanced analytical (nuclear magnetic resonance (NMR) spectroscopy, mass spectrometry (MS), chromatography, etc.) and immunological methods could contribute to the understanding of the mechanisms underlying the therapeutic effects of MSCs
Physiological effect of caffeine in neurological studies based on Susceptibility Weighted Imaging (SWI)
Introdução – O presente estudo avaliou o efeito da cafeína no valor da razão contraste ruído (CNR) em imagens SWI. Objetivos – Avaliar o efeito da cafeína
qualitativamente e quantificado pelo cálculo do valor CNR em imagens de magnitude e MIP para as estruturas: veia cerebral interna, seio sagital superior, tórcula e artéria
cerebral média. Metodologia – A população do estudo incluiu 24 voluntários saudáveis que estiveram pelo menos 24h privados da ingestão de cafeína. Adquiriram-se imagens SWI antes e após a ingestão de 100ml de café. Os voluntários foram subdivididos em quatro grupos de seis indivíduos/grupo e avaliados separadamente após decorrido um intervalo de tempo diferente para cada grupo (15, 25, 30 ou 45min pós-cafeína). Utilizou-se um scanner Siemens Avanto 1,5 T com bobine standard de crânio e os parâmetros: T2* GRE 3D de alta resolução no plano axial, TR=49; TE=40; FA=15; FOV=187x230; matriz=221x320. O processamento de imagem foi efetuado no software OsiriX® e a análise estatística no GraphPadPrism®. Resultados e Discussão – As alterações de sinal e diferenças de contraste predominaram nas estruturas venosas e não foram significantes na substância branca, LCR e artéria cerebral média. Os valores CNR pré-cafeína diferiram significativamente do pós-cafeína nas imagens de magnitude e MIP na veia cerebral interna e nas imagens de magnitude do seio sagital superior e da tórcula (p<0,0001). Não se verificaram diferenças significativas entre os grupos avaliados nos diferentes tempos pós-cafeína. Conclusões – Especulamos que a cafeína possa vir a ser usada como agente de contraste nas imagens SWI barato, eficaz e de fácil administração.ABSTRACT: Introduction – The present study investigates the effect of caffeine on
contrast-to-noise ratio (CNR) in SWI images. Purpose – Data analyses included qualitative
and quantitative measures, specifically the CNR pre and post-ingestion, in magnitude and MIP images. The structures evaluated were internal cerebral vein, superior sagital sinus, torcula, and middle cerebral artery. Methodology – Twenty-four healthy volunteers were enrolled in the study. All the volunteers were caffeine-free for 24h prior to the test. SWI images were acquired before caffeine ingestion and post-ingestion of 100 ml of coffee. The volunteers were divided into four groups of six subjects and evaluated sequentially (15, 25, 30 and 45min after caffeine). High-resolution T2* weighted 3D GRE (SWI) sequence was acquired on the axial plane on a 1.5 T (Siemens
Avanto) whole body scanner using the manufacturer’s standard head coil and the following parameters: TR=49; TE=40; FA=15; FOV=187x230; matrix=221x320. Statistics were performed with GraphPad Prism® and image analysis with Osirix®. Results and Discussion – We verified that signal alterations and contrast differences were predominant in venous structures and not significant in white matter, CSF and middle cerebral artery. The CNR values between pre and post-caffeine ingestion in magnitude and MIP images in internal cerebral vein (p<0.0001) and in magnitude images of superior sagittal sinus and tórcula showed significant differences CNR. There were no significant differences between groups evaluated at different times after the ingestion of caffeine. Conclusion – We speculate that caffeine can be used as a cost-effective, safe and easy to administrate contrast agent on SWI images
Synovia-Derived Mesenchymal Stem Cell Application in Musculoskeletal Injuries: A Review
Musculoskeletal injuries impact millions of people globally and affect their health and well-being as well as of their companion and athletic animals. Soft-tissue injuries represent almost half of these and are associated with unorganized scar tissue formation and long time-depending healing processes. Cell-based therapeutic strategies have been developed in the past decades aiming at the treatment and reversion of such disorders. Stem cells are fairly appealing in the field, being a responsive undifferentiated population, with ability to self-renew and differentiate into different lineages. Mesenchymal stem cells (MSCs) can be obtained from several adult tissues, including the synovial membrane. Synovia-derived MSCs can be found in individuals of any age and are associated to intrinsic regenerative processes, through both paracrine and cell-to-cell interactions, thus, contributing to hosts’ healing capacity. Studies have demonstrated the potential benefit of synovia-derived MSCs in these regenerative processes in both human and veterinary medicine. The purpose of this chapter is to review the literature regarding SM-MSC therapies applied to musculoskeletal disorders, in both human and veterinary medicine
Olfactory Mucosa Mesenchymal Stem Cells and Biomaterials: A New Combination to Regenerative Therapies after Peripheral Nerve Injury
The peripheral nerve injury after trauma is a common occurrence in both human and veterinary medicine and has severe consequences for the survival and quality of life of the patients. Despite the continuous efforts and the creation of diverse medical and surgical techniques, the harmful effects of this type of injury are far from being overcome. Regenerative medicine has been growing in the scientific milieu as a new therapeutic approach for different situations. Among the cell-based therapies explored, the mesenchymal stem cells are evidenced by their features, versatility and potential applications. The olfactory mucosa mesenchymal stem cells, components of the olfactory system and identified in the lamina propria, were newly identified and are still undergoing characterization, appearing as a new promise in the regenerative therapy of several tissues but with special emphasis on the nervous system in general and the peripheral nervous system in particular, for which they appear to have special regenerative aptitude
Clinical Application of Macroporous Ceramic to Promote Bone Healing in Veterinary Clinical Cases
Autogenous cancellous bone is the most effective material in promoting rapid healing and still considered the “gold standard” for evaluation of bone graft substitutes. The harvesting process to collect autologous bone is associated with complications and its availability is limited. Allogenic bone is another alternative with osteoconductive properties, and it act as a structural graft when applied in defects of long bones, but some disadvantages are also associated. The development of the bone grafts substitutes has gained tremendous popularity over the last two decades. Osteoconductive materials act as scaffolds were cells from the surrounding tissues with osteogenic capacities can lay new bone, and may be produced using different types of agents, such as bone products, ceramics, bioactive glasses, collagen, polymers, and composites. Bonelike® is produced by the incorporation of P2O5–CaO glass-based system within a hydroxyapatite matrix. Bonelike® Poro consists of polygonal granules with 2000–2800 μm and 4000–5600 μm of diameter with pore sizes range from 100 to 400 μm. This chapter will focus on the different techniques were this ceramic synthetic bone substitute was used to promote bone regeneration with special attention in both experimental and clinical cases of veterinary orthopaedics in dogs and cats, horses and ruminants, including results obtained with Bonelike®
MSCs Conditioned Media and Umbilical Cord Blood Plasma Metabolomics and Composition.
Human mesenchymal stem cells (hMSCs) from umbilical cord (UC) blood (UCB) and matrix are tested clinically for a variety of pathologies but in vitro expansion using culture media containing fetal bovine serum (FBS) is essential to achieve appropriate cell numbers for clinical use. Human UCB plasma (hUCBP) can be used as a supplement for hMSCs culture, since UCB is rich in soluble growth factors and due to worldwide increased number of cryopreserved UCB units in public and private banks, without the disadvantages listed for FBS. On the other hand, the culture media enriched in growth factors produced by these hMSCs in expansion (Conditioned medium--CM) can be an alternative to hMSCs application. The CM of the hMSCs from the UC might be a better therapeutic option compared to cell transplantation, as it can benefit from the local tissue response to the secreted molecules without the difficulties and complications associated to the engraftment of the allo- or xeno-transplanted cells. These facts drove us to know the detailed composition of the hUCBP and CM, by 1H-NMR and Multiplexing LASER Bead Technology. hUCBP is an adequate alternative for the FBS and the CM and hUCBP are important sources of growth factors, which can be used in MSCs-based therapies. Some of the major proliferative, chemotactic and immunomodulatory soluble factors (TGF-β, G-CSF, GM-CSF, MCP-1, IL-6, IL-8) were detected in high concentrations in CM and even higher in hUCBP. The results from 1H-NMR spectroscopic analysis of CM endorsed a better understanding of hMSCs metabolism during in vitro culture, and the relative composition of several metabolites present in CM and hUCBP was obtained. The data reinforces the potential use of hUCBP and CM in tissue regeneration and focus the possible use of hUCBP as a substitute for the FBS used in hMSCs in vitro culture
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