Challenges and possible clinical applications of human embryonic stem cell research

Human embryonic stem cells (hESC) are harvested from the inner cell mass of the pre-implantation embryo and possess several unique characteristics. First, they are self-renewing, meaning they can grow indefinitely in an appropriate culture environment and secondly, they are pluripotent, which means they have the potential to become nearly every cell of the human body. Consequently, hESC offer a unique insight into basic human development in vitro, allow better understanding of the genetic and molecular controls of these processes, and are of pharmaceutical interest to test or develop new drugs. The most exciting and high-profile potential application of hESC research is the possibility that such cells can be used for regenerative medicine. Still, several obstacles have to be overcome before clinical applications can be considered: (i) xeno-free derivation and culture of hESC is necessary; (ii) hESC should be safe after transplantation and (iii) their identity and behaviour should be well-known

Dental-derived stem cells and biowaste biomaterials: What’s next in bone regenerative medicine applications

The human teeth and oral cavity harbor various populations of mesenchymal stem cells (MSCs), so called dental-derived stem cells (D-dSCs) with self-renewing and multilineage differentiation capabilities. D-dSCs properties involves a strong paracrine component resulting from the high levels of bioactive molecules they secrete in response to the local microenvironment. Altogether, this viewpoint develops a general picture of current innovative strategies to employ D-dSCs combined with biomaterials and bioactive factors for regenerative medicine purposes, and offers information regarding the available scientific data and possible applications

Dental-derived stem cells and biowaste biomaterials: What's next in bone regenerative medicine applications

The human teeth and oral cavity harbor various populations of mesenchymal stem cells (MSCs), so called dental-derived stem cells (D-dSCs) with self-renewing and multilineage differentiation capabilities. D-dSCs properties involves a strong paracrine component resulting from the high levels of bioactive molecules they secrete in response to the local microenvironment. Altogether, this viewpoint develops a general picture of current innovative strategies to employ D-dSCs combined with biomaterials and bioactive factors for regenerative medicine purposes, and offers information regarding the available scientific data and possible applications

Regenerative Medicine for the Aging Brain

In the central nervous system, cholinergic and dopaminergic (DA) neurons are among the cells most susceptible to the deleterious effects of age. Thus, the basal forebrain cholinergic system is known to undergo moderate neurodegenerative changes during normal aging as well as severe atrophy in Alzheimer’s disease (AD). Parkinson’s disease (PD), a degeneration of nigro-striatal DA neurons is the most conspicuous reflection of the vulnerability of DA neurons to age. In this context, cell reprogramming offers novel therapeutic possibilities for the treatment of these devastating diseases. In effect, the generation of induced pluripotent stem cells (iPSCs) from somatic cells demonstrated that adult mammalian cells can be reprogrammed to a pluripotent state by the overexpression of a few embryonic transcription factors (TF). This discovery fundamentally widened the research horizon in the fields of disease modeling and regenerative medicine. Although it is possible to re-differentiate iPSCs to specific somatic cell types, the tumorigenic potential of contaminating iPSCs that failed to differentiate, increases the risk for clinical application of somatic cells generated by this procedure. Therefore, reprogramming approaches that bypass the pluripotent stem cell state are being explored. A method called lineage reprogramming has been recently documented. It consists of the direct conversion of one adult cell type into another by transgenic expression of multiple lineage-specific TF or microRNAs. Another approach, termed direct reprogramming, features several advantages such as the use of universal TF system and the ability to generate a rejuvenated multipotent progenitor cell population, able to differentiate into specific cell types in response to a specific differentiation factors. These novel approaches offer a new promise for the treatment of pathologies associated with the loss of specific cell types as for instance, nigral DA neurons (in PD) or basal forebrain cholinergic neurons in the early stages of AD. The above topics are reviewed here.Fil: López León, Micaela. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones Bioquímicas de La Plata ; ArgentinaFil: Reggiani, Paula Cecilia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones Bioquímicas de La Plata ; ArgentinaFil: Hereñú, Claudia Beatriz. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones Bioquímicas de La Plata ; ArgentinaFil: Goya, Rodolfo Gustavo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones Bioquímicas de La Plata ; Argentin

Loss of Pten causes tumor initiation following differentiation of murine pluripotent stem cells due to failed repression of Nanog.

Pluripotent stem cells (PSCs) hold significant promise in regenerative medicine due to their unlimited capacity for self-renewal and potential to differentiate into every cell type in the body. One major barrier to the use of PSCs is their potential risk for tumor initiation following differentiation and transplantation in vivo. In the current study we sought to evaluate the role of the tumor suppressor Pten in murine PSC neoplastic progression. Using eight functional assays that have previously been used to indicate PSC adaptation or transformation, Pten null embryonic stem cells (ESCs) failed to rate as significant in five of them. Instead, our data demonstrate that the loss of Pten causes the emergence of a small number of aggressive, teratoma-initiating embryonic carcinoma cells (ECCs) during differentiation in vitro, while the remaining 90-95% of differentiated cells are non-tumorigenic. Furthermore, our data show that the mechanism by which Pten null ECCs emerge in vitro and cause tumors in vivo is through increased survival and self-renewal, due to failed repression of the transcription factor Nanog

Renewing Universities of the Third Age : challenges and visions for the future

The University of the Third Age [UTA] has developed into a global success story. Whether holding a ‘top-down’ administrative arrangement or embodying a culture of self-help, there can be no doubt as to the triumph of UTAs in meeting the educational, social, and psychological needs of older persons. However, on the basis of fieldwork conducted at the UTA in Malta a cautionary note must be warranted. UTAs may also function as yet another example of glorified occupational therapy that is both conservative and oppressive. At the same time, UTA models seem to be running the risk of becoming obsolete as societies embark on a ‘late-modern’ model of the life course in which the sequential division between learning, work and retirement is becoming increasingly blurred. This article calls for the UTA movement to go through a cultural revolution to remain relevant to contemporary ageing lifestyles. Six key directions are forwarded: embracing a trans formational rationale, ensuring that access overcomes class, gender and ethnic biases, guaranteeing that teaching and learning strategies are skilfully suited to older persons, making greater use of eLearning techniques, extending its activities to frail and physically dependent older people especially those in residential/nursing homes, and organising activities that promote intergenerational learning.peer-reviewe

The Community Simulator: A Python package for microbial ecology

Natural microbial communities contain hundreds to thousands of interacting species. For this reason, computational simulations are playing an increasingly important role in microbial ecology. In this manuscript, we present a new open-source, freely available Python package called Community Simulator for simulating microbial population dynamics in a reproducible, transparent and scalable way. The Community Simulator includes five major elements: tools for preparing the initial states and environmental conditions for a set of samples, automatic generation of dynamical equations based on a dictionary of modeling assumptions, random parameter sampling with tunable levels of metabolic and taxonomic structure, parallel integration of the dynamical equations, and support for metacommunity dynamics with migration between samples. To significantly speed up simulations using Community Simulator, our Python package implements a new Expectation-Maximization (EM) algorithm for finding equilibrium states of community dynamics that exploits a recently discovered duality between ecological dynamics and convex optimization. We present data showing that this EM algorithm improves performance by between one and two orders compared to direct numerical integration of the corresponding ordinary differential equations. We conclude by listing several recent applications of the Community Simulator to problems in microbial ecology, and discussing possible extensions of the package for directly analyzing microbiome compositional data.Comment: 14 pages, 6 figure

Human Embryonic Stem Cell Differentiation Toward Regional Specific Neural Precursors

Human embryonic stem cells (hESCs) are self-renewing pluripotent cells that have the capacity to differentiate into a wide variety of cell types. This potentiality represents a promising source to overcome many human diseases by providing an unlimited supply of all cell types, including cells with neural characteristics. Therefore, this review summarizes early neural development and the potential of hESCs to differentiate under in vitro conditions, examining at the same time the potential use of differentiated hESCs for therapeutic applications for neural tissue and cell regeneration

Effects of innovation types on firm performance

Innovation is broadly seen as an essential component of competitiveness, embedded in the organizational structures, processes, products, and services within a firm. The objective of this paper is to explore the effects of the organizational, process, product, and marketing innovations on the different aspects of firm performance, including innovative, production, market, and financial performances, based on an empirical study covering 184 manufacturing firms in Turkey. A theoretical framework is empirically tested identifying the relationships amid innovations and firm performance through an integrated innovation-performance analysis. The results reveal the positive effects of innovations on firm performance in manufacturing industries