Search results for "SPHERES"
showing 10 items of 329 documents
Fabrication of amorphous strontium polyphosphate microparticles that induce mineralization of bone cells in vitro and in vivo.
2017
Abstract Here we describe the fabrication process of amorphous strontium-polyphosphate microparticles (“Sr-a-polyP-MP”). The effects of these particles on growth and gene expression were investigated with SaOS-2 cells as well as with human mesenchymal stem cells (MSC) and compared with those particles prepared of amorphous calcium-polyphosphate (“Ca-a-polyP-MP”) and of strontium salt. The results revealed a markedly higher stimulation of growth of MSC by “Sr-a-polyP-MP” compared to “Ca-a-polyP-MP” and a significant increase in mineralization of SaOS-2 cells, as well as an enhanced upregulation of the expression of the genes encoding for alkaline phosphatase and the bone morphogenetic protei…
Mucoadhesive solid lipid microparticles for controlled release of a corticosteroid in the chronic obstructive pulmonary disease treatment.
2017
Therapeutic efficacy of inhaled drugs is limited by rapid clearance from the site of action due to absorption into systemic circulation or metabolic degradation by alveolar macrophages. Drug delivery systems offer new solutions to clinical problems especially in the treatment of pulmonary diseases. In particular, Solid Lipid Microparticles (SLM) in the range of 3-5 µm are suggested as systems for delivery of therapeutics to the lung as, because of their size, they are able to deposit into secondary bronchi, avoiding systemic absorption typical of alveolar regions. Here, we describe two novel different SLMs prepared with chitosan and alginate for sustained release of fluticasone propionate (…
Amorphous polyphosphate–hydroxyapatite: A morphogenetically active substrate for bone-related SaOS-2 cells in vitro
2015
There is increasing evidence that inorganic calcium-polyphosphates (polyP) are involved in human bone hydroxyapatite (HA) formation. Here we investigated the morphology of the particles, containing calcium phosphate (CaP) with different concentrations of various Na-polyP concentrations, as well as their effects in cell culture. We used both SaOS-2 cells and human mesenchymal stem cells. The polymeric phosphate readily binds calcium ions under formation of insoluble precipitates. We found that addition of low concentrations of polyP (10wt.%, referred to the CaP deposits) results in an increased size of the HA crystals. Surprisingly, at higher polyP concentrations (10wt.%) the formation of cr…
Alexander Disease Mutations Produce Cells with Coexpression of Glial Fibrillary Acidic Protein and NG2 in Neurosphere Cultures and Inhibit Differenti…
2017
Background Alexander disease (AxD) is a rare disease caused by mutations in the gene encoding glial fibrillary acidic protein (GFAP). The disease is characterized by presence of GFAP aggregates in the cytoplasm of astrocytes and loss of myelin. Objectives Determine the effect of AxD-related mutations on adult neurogenesis. Methods We transfected different types of mutant GFAP into neurospheres using the nucleofection technique. Results We find that mutations may cause coexpression of GFAP and NG2 in neurosphere cultures, which would inhibit the differentiation of precursors into oligodendrocytes and thus explain the myelin loss occurring in the disease. Transfection produces cells that diff…
Narratives of Burnout and Recovery from an Agency Perspective : A Two-Year Longitudinal Study
2017
Abstract Purpose To provide knowledge about the recovery process during rehabilitation and two years later by exploring the manifestation of agency and spheres of meaning in the narratives of participants in a national rehabilitation course. Material and methods The subjects of the study were four participants in a national rehabilitation course, whose burnout levels had decreased between the initial and follow-up periods of the course. Semi-structured interviews on two occasions and an electronic questionnaire 1.5 years post rehabilitation comprised the main material. In addition, the BBI -15 (Bergen Burnout Indicator) and DEPS-screen were used. Results Thematic narrative analysis revealed…
Description of hard-sphere crystals and crystal-fluid interfaces: a comparison between density functional approaches and a phase-field crystal model.
2012
In materials science the phase field crystal approach has become popular to model crystallization processes. Phase field crystal models are in essence Landau-Ginzburg-type models, which should be derivable from the underlying microscopic description of the system in question. We present a study on classical density functional theory in three stages of approximation leading to a specific phase field crystal model, and we discuss the limits of applicability of the models that result from these approximations. As a test system we have chosen the three--dimensional suspension of monodisperse hard spheres. The levels of density functional theory that we discuss are fundamental measure theory, a …
Monte Carlo simulations of the solid-liquid transition in hard spheres and colloid-polymer mixtures
2010
Monte Carlo simulations at constant pressure are performed to study coexistence and interfacial properties of the liquid-solid transition in hard spheres and in colloid-polymer mixtures. The latter system is described as a one-component Asakura-Oosawa (AO) model where the polymer's degrees of freedom are incorporated via an attractive part in the effective potential for the colloid-colloid interactions. For the considered AO model, the polymer reservoir packing fraction is eta_p^r=0.1 and the colloid-polymer size ratio is q=sigma_p/\sigma=0.15 (with sigma_p and sigma the diameter of polymers and colloids, respectively). Inhomogeneous solid-liquid systems are prepared by placing the solid fc…
Coupling between bulk- and surface chemistry in suspensions of charged colloids
2013
The ionic composition and pair correlations in fluid phases of realistically salt-free charged colloidal sphere suspensions are calculated in the primitive model. We obtain the number densities of all ionic species in suspension, including low-molecular weight microions, and colloidal macroions with acidic surface groups, from a self-consistent solution of a coupled physicochemical set of nonlinear algebraic equations and non-mean-field liquid integral equations. Here, we study suspensions of colloidal spheres with sulfonate or silanol surface groups, suspended in demineralized water that is saturated with carbon dioxide under standard atmosphere. The only input required for our theoretical…
Trehalose-hydroxyethylcellulose microspheres containing vancomycin for topical drug delivery.
2001
Abstract A new formulation, in which vancomycin is entrapped into trehalose and hydroxyethylcellulose (Natrosol ® ) spherical matrices, is described. Microspheres were produced by the solvent evaporation method. The entrapped drug was fully recovered following microspheres dissolution. Differential scanning calorimetry analyses proved that Natrosol maintains trehalose in its amorphous form. The stabilizing effects of trehalose on vancomycin were evaluated even after long storage and heating of microspheres. Calorimetric data indicated no decomposition of the entrapped drug. In vitro drug release, already performed by using a general two-compartment linear time-invariant open model, suggests…
Pituispheres Contain Genetic Variants Characteristic to Pituitary Adenoma Tumor Tissue
2020
The most common type of pituitary neoplasms is benign pituitary adenoma (PA). Clinically significant PAs affect around 0.1% of the population. Currently, there is no established human PA cell culture available and when PA tumor cells are cultured they form two distinct types depending on culturing conditions either free-floating aggregates also known as pituispheres or cells adhering to the surface of cell plates and displaying mesenchymal stem-like properties. The aim of this study was to trace the origin of sphere-forming and adherent pituitary cell cultures and characterize the potential use of these surgery derived cell lines as PA model. We carried out a paired-end exome sequencing of …