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Inherent Feature (inherent + feature)
Selected AbstractsSurface protein patterns govern morphology, proliferation, and expression of cellular markers but have no effect on physiological properties of cortical precursor cellsJOURNAL OF NEUROSCIENCE RESEARCH, Issue 11 2008Anna K. Magnusson Abstract The ability to differentiate and give rise to neurons, astrocytes, and oligodendrocytes is an inherent feature of neural stem cells, which raises hopes for cell-based therapies of neurodegenerative diseases. However, there are many hurdles to cross before such regimens can be applied clinically. A considerable challenge is to elucidate the factors that contribute to neural differentiation. In this study, we evaluated the possibility of steering neuronal maturation by growing cortical precursor cells on microscale surface patterns of extracellular matrix (ECM) proteins. When the cells were encouraged to extend processes along lines of ECM proteins, they displayed a much more mature morphology, less proliferation capacity, and greater expression of a neuronal marker in comparison with cells grown in clusters on ECM dots. This implied that the growth pattern alone could play a crucial role for neural differentiation. However, in spite of the strikingly different morphology, when performing whole-cell patch-clamp experiments, we never observed any differences in the functional properties between cells grown on the two patterns. These results clearly demonstrate that morphological appearances are not representative measures of the functional phenotype or grade of neuronal maturation, stressing the importance of complementary electrophysiological evidence. To develop successful transplantation therapies, increased cell survival is critical. Because process-bearing neurons are sensitive and break easily, it would be of clinical interest to explore further the differentiating capacity of the cells cultured on the ECM dot pattern, described in this article, which are devoid of processes but display the same functional properties as neurons with mature morphology. © 2008 Wiley-Liss, Inc. [source] "Free-Floating" Desmosomes in Lipoid Proteinosis: An Inherent Defect in Keratinocyte Adhesion?PEDIATRIC DERMATOLOGY, Issue 1 2006Jon A. Dyer M.D. However, the characteristic manifestation in children , erosive, crusted lesions that lead to scarring , is rarely discussed and poorly understood. Lipoid proteinosis results from mutations in extracellular matrix protein 1, but the function of this protein is largely unknown. We performed ultrastructural studies on lesional epidermis, cultured monolayer keratinocytes, and raft keratinocyte cultures from blistering lesions of a child with lipoid proteinosis. All sections showed the dissociation of relatively intact desmosomes from keratinocytes, with desmosomes that were "free-floating" in the intercellular spaces or attached by thin strands to the cell membrane. These changes were present in serial sections of both tissue and cultured keratinocytes, suggesting this observation to be an inherent feature of keratinocytes devoid of extracellular matrix protein 1, rather than an artifact. Although additional patients should be studied, the diminished appearance of the inner dense plaque , the region of attachment of keratin intermediate filaments to desmosomal proteins , provides preliminary evidence that extracellular matrix protein 1 may participate in attaching keratin intermediate filaments to desmosomal region protein(s). [source] Phenotypic variation during cloning procedures: Analysis of the growth behavior of clonal cell linesBIOTECHNOLOGY & BIOENGINEERING, Issue 3 2006Louise M. Barnes Abstract The production of recombinant protein from mammalian cells is a key feature of the biotechnology industry. However, the generation of recombinant mammalian cell lines is still largely performed on an empirical basis and there are many potential areas for enhancement. We have shown previously that despite two rounds of limiting dilution cloning (LDC) of recombinant cell lines, there remained a high degree of heterogeneity in the resulting cell lines. We suggested that a rapid phenotypic drift occurred with these cells. It was unclear if this was a consequence of the added burden of production of a recombinant protein, the selection procedures, or merely an inherent feature of cell growth in culture. To address this, we have subjected untransfected (parental) cells to three successive rounds of LDC and monitored the growth properties of the resultant cells. The results show that despite repeated rounds of cloning, it was not possible to obtain phenotypically similar cell lines. We also demonstated that this phenotypic drift is not due to gross changes in the protein p27, a key regulators of the cell cycle. Although cells with a range of growth properties were observed even after three rounds of cloning, the variation in growth patterns between cell lines decreased after cloning. Hence, we suggest that by cloning it may be possible to generate untransfected cells, which have particular growth properties. Starting with a well-defined population of parental cells may aid in the subsequent generation of tranfectants with desired growth properties. © 2006 Wiley Periodicals, Inc. [source] Bayesian hierarchical models in ecological studies of health,environment effectsENVIRONMETRICS, Issue 2 2003Sylvia Richardson Abstract We describe Bayesian hierarchical models and illustrate their use in epidemiological studies of the effects of environment on health. The framework of Bayesian hierarchical models refers to a generic model building strategy in which unobserved quantities (e.g. statistical parameters, missing or mismeasured data, random effects, etc.) are organized into a small number of discrete levels with logically distinct and scientifically interpretable functions, and probabilistic relationships between them that capture inherent features of the data. It has proved to be successful for analysing many types of complex epidemiological and biomedical data. The general applicability of Bayesian hierarchical models has been enhanced by advances in computational algorithms, notably those belonging to the family of stochastic algorithms based on Markov chain Monte Carlo techniques. In this article, we review different types of design commonly used in studies of environment and health, give details on how to incorporate the hierarchical structure into the different components of the model (baseline risk, exposure) and discuss the model specification at the different levels of the hierarchy with particular attention to the problem of aggregation (ecological) bias. Copyright © 2003 John Wiley & Sons, Ltd. [source] | ||||||||||