87 research outputs found

    The Use of Alginate Hydrogels for the Culture of Mesenchymal Stem Cells (MSCs): In Vitro and In Vivo Paradigms

    Get PDF
    Alginate hydrogels have been widely used in stem cell cultures due to their biocompatibility, malleable nature, high water content, enhanced mass transport properties, and their functionalization with bioactive molecules providing cues that modulate cell proliferation and differentiation. Mesenchymal stem cells (MSCs) are extensively utilized in clinical cellular therapies because of their differentiation efficiency, their immunosuppressive properties, and them not being tumorigenic when implanted in vivo. MSCs are isolated from numerous fetal and adult tissues, suitable for both autologous and allogeneic applications. Consequently, alginate hydrogels/MSCs have been applied in vivo for the treatment of a wide variety of musculoskeletal, cardiac, neural, and endocrine disorders. This chapter will review the use of alginate hydrogels (physical properties and functionalization) for MSC culture in vitro (various culture systems) and the application of alginate/MSC implants (animal models and human applications) for cellular therapy purposes in vivo

    How can the information system be directed to contribute to the overall performance of administrations status of Moroccan universities

    Get PDF
    Received Jun 12th, 2019 An information system necessarily has a mode of governance. Whatever their nature, there are rules applying to this system. And control mechanisms are usually in place. Thus, it is not a question of creating the governance of the information system, but really about making it a tool of management and improvement. When ranking countries on the e-government scale, Morocco ranks 140 out of 192 UN member states. Yet Morocco had introduced computers in the administration since the early 60s. This ranking, which illustrates the delay by the computer in the Moroccan administration, and therefore the difficulties that Morocco encounters in the improvement performance of its administration, should it not be attributed to a deficit in public management of information systems? The objective of this article is to evaluate the management of information systems in Moroccan public administrations and specifically to dissect the profile of Moroccan universities

    A New Collaborative Risk Assessment Model for Cloud Computing

    Get PDF
    Cloud computing has recently emerged a new paradigm by introducing potential benefits to Cloud users. Although the advantage of cloud computing are tremendous, number of security risk are emerging in association with cloud usage that need to be assessed. Assessing risk in Cloud computing environment remains an open research issue. This paper presents a collaborative risk assessment model for cloud computing, which is in compliance with all the specific characteristics of the Cloud Computing

    Management of undiagnosed pheochromocytoma with acute appendicitis

    Get PDF
    The authors reported and discussed management a case of undiagnosed pheochromocytoma suspected because the catastrophic hemodynamic changes in a patient with an acute appendicitis

    Peri-partum cardiomyopathy in a pregnant woman at term revealed by acute pulmonary edema: what to do in front this catastrophic situation?

    Get PDF
    Peripartum Cardiomyopathy is insufficient congestive heart occurring in the last month of pregnancy and 5  months after delivery, in the absence of preexisting heart disease and identified etiology. This heart disease is associated with echocardiography systolic dysfunction and left ventricular dilatation. Its incidence ranges from 1/3000 to 1/15000, depending on the region, including much higher in some African countries, it particularlyconcern women over 30 years, multiparous and multiple pregnancies. The pathogenesis remains unclear, the prognosis is closely related to the complete recovery of cardiac function. We report through the clinical case of a woman aged 33 years admitted to the ICU for acute pulmonary edema of sudden onset of a term pregnancy and what to do before this critical situationKey words: Peri-partum, cardiomyopathy, acute pulmonary edem

    Changements climatiques au Maroc: quels systĂšmes de culture et quelles biotechnologies pour s'y adapter ?

    Get PDF
    A prospective study is presented on the probable impact of climate change on cropping and livestock systems in Morocco. According to field reports and taking into account the limits of such studies, the direct effect of global warming can lead (and this is already the case in other countries) to a new varietal redistribution for the cold demanding species such as rosaceous. Apple cultivars such as the Golden group risk disappearing from the mountains to give way to others less cold demanding cultivars such as the Gala group. The banana and the avocado risk migrating to more continental regions while the olive and the citrus trees will move towards the foot of mountains. Global warming may also induce changes in livestock and cropping systems moving the drought boundary towards the center and north of the country. The arid would probably return to the semi-desert or desert space, the semi-arid would pass partly to the arid zone and the favorable Bour will be semi-arid. As a result to this change, we may expect a lack of water resource inducing an abandoning of grain crops in the arid stage for livestock. Also, we may expect a revising of the existing cropping systems within the rain-fed areas by introducing a little more Dry Farming and early cultivars. In the large irrigated perimeters, it would be necessary to exclude, due to the lack of water, the high water consuming crops such as rice and sugar cane for highly efficient and remunerative crops. Excessive drought predicted by some recent models also suggests a greater need for dams as soon as possible in order to take advantage of the rainy years with exceptional rainfall. On the other hand, it would also be necessary to optimize water management by moving rapidly towards drip irrigation, and by transferring water surplus to deficient areas. Even though the use of seawater as a resource for irrigation seems so far away, the advances in desalinization technology and cost will allow either large scale use of seawater in agriculture or finding new salinity tolerant cultivars. In Morocco, we should think of desalinization with renewable energies (solar, wind) and the use of this water mainly in coastal areas where climate, land quality, sun and wind are adequate to these projects. To anticipate the future of food security of the country, attention should be given to the use of readily available resources to overcome the structural deficit in wheat starch and animal protein. The study suggests the use of other starch sources that Morocco can produce easily such as potato. For animal protein, we suggest fisheries resources which are still underused by the population. Keywords: Climate change, cropping system, livestock, Biotechnology, Morocco.On prĂ©sente une Ă©tude prospective concernant l’impact probable des changements climatiques sur les systĂšmes de culture et d’élevage au Maroc. D’aprĂšs le constat de terrain et dans les limites de ce que signifie ce genre d’étude, l’effet direct du rĂ©chauffement climatique peut conduire Ă  terme (et c’est dĂ©jĂ  le cas dans certaines contrĂ©es) Ă  la nĂ©cessitĂ© d’une redistribution variĂ©tale pour des espĂšces exigeantes en froid comme les rosacĂ©es. Des variĂ©tĂ©s de pomme, telle que le groupe des Golden, risquent de disparaĂźtre des montagnes pour laisser la place Ă  d’autres moins exigeantes comme le groupe des Gala. Le bananier et l’avocatier risquent de migrer vers les rĂ©gions un peu plus continentales, l’olivier et les agrumes un peu plus vers le pied de la montagne. Le rĂ©chauffement climatique peut aussi obliger Ă  faire Ă©voluer les systĂšmes d’élevage et de culture en faisant dĂ©placer la frontiĂšre de la sĂ©cheresse un peu plus vers le centre et le nord du pays; l’aride serait peut-ĂȘtre envahi par la dĂ©sertification, le semi-aride passerait en partie Ă  l’étage aride et le Bour dit favorable en partie dans le semi-aride. Comme corollaire Ă  ce changement, il faudrait s’attendre Ă  une perte de potentiel de ressources en eau qui obligerait probablement Ă  abandonner les cultures pour le grain dans l’étage aride oĂč il n’y aurait plus suffisamment de pluie, au profit de l’élevage, et Ă  revoir les systĂšmes de culture en introduisant un peu plus d’aridoculture et de variĂ©tĂ©s plus prĂ©coces dans les autres Ă©tages d’agriculture pluviale. Dans les grands pĂ©rimĂštres irriguĂ©s, par manque d’eau l’on serait dans l’obligation de soustraire de ces pĂ©rimĂštres toute culture grande consommatrice d’eau telles que le riz et la canne Ă  sucre et, pour des impĂ©ratifs d’une meilleure valorisation de ce qui va rester, Ă  ne garder que des cultures Ă  forte efficience et fortement rĂ©munĂ©ratrices. La sĂ©cheresse excessive prĂ©visible par certains modĂšles rĂ©cents suggĂšre aussi un besoin plus important en barrages dans les plus brefs dĂ©lais possibles afin de profiter des annĂ©es trĂšs pluvieuses Ă  apports d’eau exceptionnels. Mais, il faudrait aussi optimiser la gestion de cette eau en Ă©voluant rapidement vers la gĂ©nĂ©ralisation de l’irrigation localisĂ©e et en transfĂ©rant l’excĂ©dent d’eau vers les autres rĂ©gions dĂ©ficitaires. Quoi que cela puisse paraĂźtre encore lointain, l’eau de mer en tant que ressource inĂ©puisable pour l’irrigation est la vraie solution Ă  terme Ă  condition de lui trouver le dĂ©clic technologique pour un usage en grande agriculture Ă  l’instar de l’eau conventionnelle ou de dĂ©couvrir des variĂ©tĂ©s permettant de l’utiliser en l’état. Au Maroc, il faudrait penser au dessalage au moyen d’énergies renouvelables (solaire, Ă©olien) et Ă  l’utilisation de cette eau dans une premiĂšre phase, dans les zones cĂŽtiĂšres oĂč climat, qualitĂ© des terres, soleil et vent sont trĂšs favorables Ă  ces projets. Pour anticiper l’avenir au plan sĂ©curitĂ© alimentaire du pays, il faudrait envisager l’emploi de ressources facilement mobilisables pour combler le dĂ©ficit structurel en amidon de blĂ© et en protĂ©ines animales. L’étude suggĂšre le recours Ă  d’autres sources d’amidon que le Maroc peut produire aisĂ©ment comme la pomme de terre, et pour le dĂ©ficit en protĂ©ines, une plus forte consommation de ressources halieutiques encore largement sous utilisĂ©es par la population. Mots-clĂ©s: Changements climatiques, systĂšme de culture, systĂšmes d’élevage, biotechnologies, Maroc

    Changements climatiques au Maroc: quels systĂšmes de culture et quelles biotechnologies pour s'y adapter ?

    Get PDF
    A prospective study is presented on the probable impact of climate change on cropping and livestock systems in Morocco. According to field reports and taking into account the limits of such studies, the direct effect of global warming can lead (and this is already the case in other countries) to a new varietal redistribution for the cold demanding species such as rosaceous. Apple cultivars such as the Golden group risk disappearing from the mountains to give way to others less cold demanding cultivars such as the Gala group. The banana and the avocado risk migrating to more continental regions while the olive and the citrus trees will move towards the foot of mountains. Global warming may also induce changes in livestock and cropping systems moving the drought boundary towards the center and north of the country. The arid would probably return to the semi-desert or desert space, the semi-arid would pass partly to the arid zone and the favorable Bour will be semi-arid. As a result to this change, we may expect a lack of water resource inducing an abandoning of grain crops in the arid stage for livestock. Also, we may expect a revising of the existing cropping systems within the rain-fed areas by introducing a little more Dry Farming and early cultivars. In the large irrigated perimeters, it would be necessary to exclude, due to the lack of water, the high water consuming crops such as rice and sugar cane for highly efficient and remunerative crops. Excessive drought predicted by some recent models also suggests a greater need for dams as soon as possible in order to take advantage of the rainy years with exceptional rainfall. On the other hand, it would also be necessary to optimize water management by moving rapidly towards drip irrigation, and by transferring water surplus to deficient areas. Even though the use of seawater as a resource for irrigation seems so far away, the advances in desalinization technology and cost will allow either large scale use of seawater in agriculture or finding new salinity tolerant cultivars. In Morocco, we should think of desalinization with renewable energies (solar, wind) and the use of this water mainly in coastal areas where climate, land quality, sun and wind are adequate to these projects. To anticipate the future of food security of the country, attention should be given to the use of readily available resources to overcome the structural deficit in wheat starch and animal protein. The study suggests the use of other starch sources that Morocco can produce easily such as potato. For animal protein, we suggest fisheries resources which are still underused by the population. Keywords: Climate change, cropping system, livestock, Biotechnology, Morocco.On prĂ©sente une Ă©tude prospective concernant l’impact probable des changements climatiques sur les systĂšmes de culture et d’élevage au Maroc. D’aprĂšs le constat de terrain et dans les limites de ce que signifie ce genre d’étude, l’effet direct du rĂ©chauffement climatique peut conduire Ă  terme (et c’est dĂ©jĂ  le cas dans certaines contrĂ©es) Ă  la nĂ©cessitĂ© d’une redistribution variĂ©tale pour des espĂšces exigeantes en froid comme les rosacĂ©es. Des variĂ©tĂ©s de pomme, telle que le groupe des Golden, risquent de disparaĂźtre des montagnes pour laisser la place Ă  d’autres moins exigeantes comme le groupe des Gala. Le bananier et l’avocatier risquent de migrer vers les rĂ©gions un peu plus continentales, l’olivier et les agrumes un peu plus vers le pied de la montagne. Le rĂ©chauffement climatique peut aussi obliger Ă  faire Ă©voluer les systĂšmes d’élevage et de culture en faisant dĂ©placer la frontiĂšre de la sĂ©cheresse un peu plus vers le centre et le nord du pays; l’aride serait peut-ĂȘtre envahi par la dĂ©sertification, le semi-aride passerait en partie Ă  l’étage aride et le Bour dit favorable en partie dans le semi-aride. Comme corollaire Ă  ce changement, il faudrait s’attendre Ă  une perte de potentiel de ressources en eau qui obligerait probablement Ă  abandonner les cultures pour le grain dans l’étage aride oĂč il n’y aurait plus suffisamment de pluie, au profit de l’élevage, et Ă  revoir les systĂšmes de culture en introduisant un peu plus d’aridoculture et de variĂ©tĂ©s plus prĂ©coces dans les autres Ă©tages d’agriculture pluviale. Dans les grands pĂ©rimĂštres irriguĂ©s, par manque d’eau l’on serait dans l’obligation de soustraire de ces pĂ©rimĂštres toute culture grande consommatrice d’eau telles que le riz et la canne Ă  sucre et, pour des impĂ©ratifs d’une meilleure valorisation de ce qui va rester, Ă  ne garder que des cultures Ă  forte efficience et fortement rĂ©munĂ©ratrices. La sĂ©cheresse excessive prĂ©visible par certains modĂšles rĂ©cents suggĂšre aussi un besoin plus important en barrages dans les plus brefs dĂ©lais possibles afin de profiter des annĂ©es trĂšs pluvieuses Ă  apports d’eau exceptionnels. Mais, il faudrait aussi optimiser la gestion de cette eau en Ă©voluant rapidement vers la gĂ©nĂ©ralisation de l’irrigation localisĂ©e et en transfĂ©rant l’excĂ©dent d’eau vers les autres rĂ©gions dĂ©ficitaires. Quoi que cela puisse paraĂźtre encore lointain, l’eau de mer en tant que ressource inĂ©puisable pour l’irrigation est la vraie solution Ă  terme Ă  condition de lui trouver le dĂ©clic technologique pour un usage en grande agriculture Ă  l’instar de l’eau conventionnelle ou de dĂ©couvrir des variĂ©tĂ©s permettant de l’utiliser en l’état. Au Maroc, il faudrait penser au dessalage au moyen d’énergies renouvelables (solaire, Ă©olien) et Ă  l’utilisation de cette eau dans une premiĂšre phase, dans les zones cĂŽtiĂšres oĂč climat, qualitĂ© des terres, soleil et vent sont trĂšs favorables Ă  ces projets. Pour anticiper l’avenir au plan sĂ©curitĂ© alimentaire du pays, il faudrait envisager l’emploi de ressources facilement mobilisables pour combler le dĂ©ficit structurel en amidon de blĂ© et en protĂ©ines animales. L’étude suggĂšre le recours Ă  d’autres sources d’amidon que le Maroc peut produire aisĂ©ment comme la pomme de terre, et pour le dĂ©ficit en protĂ©ines, une plus forte consommation de ressources halieutiques encore largement sous utilisĂ©es par la population. Mots-clĂ©s: Changements climatiques, systĂšme de culture, systĂšmes d’élevage, biotechnologies, Maroc

    Smad-Runx interactions during chondrocyte maturation

    Get PDF
    BACKGROUND: Intracellular signaling triggered by bone morphogenetic proteins (BMPs) results in activated Smad complexes that regulate transcription of BMP-responsive genes. However, the low specificity of Smad binding to regulatory sequences implies that additional tissue-specific transcription factors are also needed. Runx2 (Cbfal) is a transcription factor required for bone formation. We have examined the role of Smads and Runx2 in BMP induction of type X collagen, which is a marker of chondrocyte hypertrophy leading to endochondral bone formation. METHODS: Pre-hypertrophic chondrocytes from the cephalic portion of the chick embryo sternum were placed in culture in the presence or absence of rhBMP-2. Cultures were transiently transfected with DNA containing the BMP-responsive type X collagen promoter upstream of the luciferase gene. The cultures were also transfected with plasmids, causing over-expression of Smads or Runx2, or both. After 24-48 hours, cell extracts were examined for levels of luciferase expression. RESULTS: In the presence of BMP-2, chondrocytes over-expressing BMP-activated Smadl or Smad5 showed significant enhancement of luciferase production compared with that seen with BMP alone. This enhancement was not observed with over-expression of Smad2, a transforming growth factor beta (TGF-beta)-activated Smad. Overexpression of Runx2 in BMP-treated cultures increased transcriptional activity to levels similar to those seen with Smads 1 or 5. When chondrocytes were simultaneously transfected with both Runx2 and Smad 1 or 5, promoter activity was further increased, indicating that BMP-stimulated Smad activity can be augmented by increasing the levels of Runx2. CONCLUSIONS: These results implicate the skeletal tissue transcription factor Runx2 in regulation of chondrocyte hypertrophy and suggest that maximal transcription of the type X collagen gene in pre-hypertrophic chondrocytes involves interaction of BMP-stimulated Smads with Runx2. Clinical Relevance: Many skeletal abnormalities are associated with impaired regulation of chondrocyte hypertrophy in growth plates. These studies demonstrate that both BMP-activated Smads and Runx2 levels can modulate chondrocyte transition to hypertrophy

    The cell cycle regulator p27kip1 contributes to growth and differentiation of osteoblasts

    Get PDF
    The cyclin-dependent kinase (cdk) inhibitors are key regulators of cell cycle progression. p27 and p21 are members of the Cip/Kip family of cdk inhibitors and regulate cell growth by inactivating cell cycle stage-specific CDK-cyclin complexes. Because down-regulation of osteoprogenitor proliferation is a critical step for osteoblast differentiation, we investigated expression of p27 and p21 during development of the osteoblast phenotype in rat calvarial osteoblasts and in proliferating and growth-inhibited osteosarcoma ROS 17/2.8 cells. Expression of these proteins indicates that p21, which predominates in the growth period, is related to proliferation control. p27 levels are maximal postproliferatively, suggesting a role in the transition from cell proliferation to osteoblast differentiation. We directly examined the role of p27 during differentiation of osteoprogenitor cells derived from the bone marrow (BM) of p27-/- mice. BM cells from p27 null mice exhibited increased proliferative activity compared with BM cells from wild-type mice and formed an increased number and larger size of osteoblastic colonies, which further differentiated to the mineralization stage. Although p27-/- adherent marrow cells proliferate faster, they retain competency for differentiation, which may result, in part, from observed higher p21 levels compared with wild type. Histological studies of p27-/- bones also showed an increased cellularity in the marrow cavity compared with the p27+/+. The increased proliferation in bone does not lead to tumorigenesis, in contrast to observed adenomas in the null mice. Taken together, these findings indicate that p27 plays a key role in regulating osteoblast differentiation by controlling proliferation-related events in bone cells

    Reduced COX-2 Expression in Aged Mice Is Associated With Impaired Fracture Healing

    Get PDF
    The cellular and molecular events responsible for reduced fracture healing with aging are unknown. Cyclooxygenase 2 (COX-2), the inducible regulator of prostaglandin E2 (PGE2) synthesis, is critical for normal bone repair. A femoral fracture repair model was used in mice at either 7–9 or 52–56 wk of age, and healing was evaluated by imaging, histology, and gene expression studies. Aging was associated with a decreased rate of chondrogenesis, decreased bone formation, reduced callus vascularization, delayed remodeling, and altered expression of genes involved in repair and remodeling. COX-2 expression in young mice peaked at 5 days, coinciding with the transition of mesenchymal progenitors to cartilage and the onset of expression of early cartilage markers. In situ hybridization and immunohistochemistry showed that COX-2 is expressed primarily in early cartilage precursors that co-express col-2. COX-2 expression was reduced by 75% and 65% in fractures from aged mice compared with young mice on days 5 and 7, respectively. Local administration of an EP4 agonist to the fracture repair site in aged mice enhanced the rate of chondrogenesis and bone formation to levels observed in young mice, suggesting that the expression of COX-2 during the early inflammatory phase of repair regulates critical subsequent events including chondrogenesis, bone formation, and remodeling. The findings suggest that COX-2/EP4 agonists may compensate for deficient molecular signals that result in the reduced fracture healing associated with aging
    • 

    corecore