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Vitro Culture System (vitro + culture_system)
Selected Abstracts, -Carotene is incorporated or mobilized along with triglycerides in bovine adipose tissue in response to insulin or epinephrineJOURNAL OF ANIMAL PHYSIOLOGY AND NUTRITION, Issue 1 2009E. Arias Summary Pasture fed cattle ingest substantial amounts of , -carotene (, -C). Not all of the carotenoid compound is transformed into vitamin A, but the surplus is deposited in adipose tissue (AT). The mechanisms of , -C incorporation and mobilization are unknown. Two experiments were conducted using explants from bovine AT cultured in vitro. First, , -C incorporation by explants from three animals was examined with different , -C concentrations (0, 1, 5 and 20 ,m) and different times of incubation (every 5 h up to 25 h). The data showed a significant increase of , -C concentration in explants only for 20 ,m, -C. Secondly, effects of insulin and epinephrine on , -C and triglyceride (TG) contents of explants were studied. Explants from six animals were incubated with either hormone and 0 or 20 ,m, -C for 20 h. Both TG and , -C contents were affected positively by insulin and negatively by epinephrine. Interestingly, changes in ratios of , -C/TG (hormone vs. control) were similar (1.7 × 10,3 and 1.8 × 10,3), respectively, for insulin and epinephrine, indicating that , -C level is directly related to TG content. We also report the presence of mRNA for , -C 15, 15, oxygenase in bovine AT. The in vitro culture system using explants from bovine AT is a promising model to investigate factors that might affect the accumulation and metabolism of , -C. [source] Melatonin influences the proliferative and differentiative activity of neural stem cellsJOURNAL OF PINEAL RESEARCH, Issue 4 2007Takahiro Moriya Abstract:, Though melatonin has a wide variety of biological functions, its effects on the neural stem cells (NSCs) is still unknown. In this study, we examined the effects of melatonin at either physiological (0.01,10 nm) or pharmacological concentrations (1,100 ,m) on the proliferation and neural and astroglial differentiation of NSCs derived from the mouse embryo striatum using an in vitro culture system. We found that melatonin at pharmacological concentrations, but not at physiological concentrations, suppressed epidermal growth factor (EGF)-stimulated NSC proliferation (increment of viable cells, DNA synthesis and neurosphere formation) in a concentration-dependent manner. Furthermore, treatment with melatonin at a pharmacological concentration during the proliferation period facilitated 1% FBS-induced neural differentiation of NSCs without affecting the astroglial differentiation. In contrast, the treatment with melatonin at pharmacological concentrations during the differentiation period decreased the neural differentiation of the NSCs. As with melatonin, MCI-186, an antioxidant, suppressed EGF-stimulated NSC proliferation and facilitated the subsequent neural differentiation of NSCs. These results suggest that melatonin exerts potent modulatory effects on NSC functions including the suppression of the proliferation and facilitation of neuronal differentiation, likely via its antioxidant activity. As neurogenesis is thought to play an important role in ameliorating the deficit in neurodegenerative diseases, melatonin might be beneficially used for the treatment diseases such as cerebral infarction. [source] In Vitro Culture of the Obligate Parasite Spongospora subterranea (Cercozoa; Plasmodiophorida) Associated with Root-Inducing Transferred-DNA Transformed Potato Hairy RootsTHE JOURNAL OF EUKARYOTIC MICROBIOLOGY, Issue 6 2007XINSHUN QU ABSTRACT. Spongospora subterranea is a soil-borne, obligate parasitic protist that causes powdery scab of potatoes. In this study, an in vitro culture system was developed for the maintenance and proliferation of the protist in potato hairy roots. The hairy roots of potato were induced in vitro with Agrobacterium rhizogenes. Cystosori of S. subterranea from potato scab lesions were surface disinfested and used to inoculate potato hairy roots. Plasmodia, zoosporangia, and cystosori were observed microscopically in the hairy roots within 6 wk after inoculation, indicating the completion of the life cycle of S. subterranea in vitro. This is the first in vitro culture system for S. subterranea, and will be a valuable tool to study fundamental and practical aspects of the biology of the parasite. [source] Continuous Delivery of Biomaterials to the Skin,Percutaneous Device Interface Using a Fluid PumpARTIFICIAL ORGANS, Issue 2 2010Antonio Peramo Abstract We have developed an in vitro culture system composed of organotypic human skin explants interfaced with titanium rods attached to a fluid pump. This device was designed to mimic the process of natural mucosa delivery at the point where a rigid, permanent object penetrates living skin. Full thickness human breast skin explants discarded from surgeries were cultured at different time points at the air-liquid interface. The skin specimens were punctured to fit at the bottom of hollow cylindrical titanium rods. Sodium lauryl sulfate (SLS) was delivered continuously to the specimens through the rods by using an attached fluid pump. Histological analysis of the skin explants as well as no-pump controls was then performed. Our results show substantial differences between controls, where no material was pumped at the interface of rod,skin, and specimens treated with SLS, indicating that the technique of pumping the material is effective in producing observable epithelial changes. These results suggest that an adaptation of this type of device may be useful for the treatment of complications arising from the contact between tissues and percutaneous devices in vivo. [source] Differences in regulatory pathways identify subgroups of T cell-derived Th2 cytokinesCLINICAL & EXPERIMENTAL IMMUNOLOGY, Issue 1 2000K. Rafiq We analysed regulatory mechanisms involved in the production of Th2 cytokines by freshly isolated human T cells. We used an in vitro culture system in which the primary signal was provided by a cross-linking anti-CD3 MoAb presented on the Fc receptors of P815 cells. Both CD80 and CD86, expressed on transfected P815 cells, were able to provide efficient costimulation for the production of IL-4, IL-5 and IL-13. IL-2 was also highly important for induction of all three Th2 cytokines. However, differences between IL-4 on the one hand and IL-5 and IL-13 on the other hand were observed when sensitivity to cyclosporin A (CsA) was studied. CsA (an inhibitor of calcineurin phosphatase activity) strongly inhibited IL-4 production, but it did either not affect or even increased IL-5 and IL-13 production. In accordance with this, CD80 and phorbol myristate acetate (PMA) (without anti-CD3 or calcium ionophore) were sufficient to induce production of IL-5 and IL-13, but not of IL-4. The subgrouping of Th2 cytokines was further confirmed at another level on the basis of differences in cell sources: IL-4 was predominantly produced by CD4+ T cells, while IL-5 and IL-13 were produced by both CD4+ and CD8+ T cells. Thus, differences in cell sources and in the requirement of the calcium/calcineurin-signalling pathway allowed us to identify two subgroups (IL-4 and IL-5/IL-13) among human Th2-type T cell cytokines. [source] Mechanisms of morphogen movementDEVELOPMENTAL NEUROBIOLOGY, Issue 4 2005Maura Strigini Abstract Morphogens are defined as signaling molecules that are produced locally, yet act directly at a distance to pattern the surrounding field of cells in a concentration-dependent manner. In recent years many laboratories have devoted their attention to how morphogens actually reach distant cells. Several models have been proposed, including diffusion in the extracellular space and planar transcytosis. A combination of genetic, developmental, and cell-biological approaches have been taken to tackle this issue. I will present the models and discuss the types of experiments that have been designed to test them. It stands out that most of the work has been carried out in Drosophila. Morphogens contribute to patterning of the vertebrate nervous system, and the same signaling molecules have recently been shown to play important, possibly instructive, roles in axon guidance. Little, if anything, is known about the movement of morphogens in the context of nervous system development. The long-standing tradition of biophysical studies on diffusion in the brain extracellular space, along with the sophisticated in vitro culture systems developed in neurobiology laboratories, may provide new tools and ideas to test these models in a new context. © 2005 Wiley Periodicals, Inc. J Neurobiol 64: 324,333, 2005 [source] Modulation of immune response with cytotoxic T-lymphocyte-associated antigen 4 immunoglobulin-induced anergic T cells in chronic idiopathic thrombocytopenic purpura,JOURNAL OF THROMBOSIS AND HAEMOSTASIS, Issue 1 2008X.-L. ZHANG Summary.,Background:,Platelet glycoprotein (GP)-reactive CD4+ T cells are essential for the stimulation and maintenance of antiplatelet autoantibody production in chronic idiopathic thrombocytopenic purpura (ITP). Blocking costimulatory signals could result in platelet-specific T-cell anergy. Methods:,GP-specific CD4+ T cells from patients with ITP were made anergic using cytotoxic T-lymphocyte-associated antigen 4 immunoglobulin (CTLA4-Ig). The CTLA4-Ig-induced GP-specific anergic T cells were investigated for their inhibitory function on GP-reactive T-cell proliferation and antibody production with in vitro culture systems. To further analyze their tolerizing mechanisms, we cocultured GP-anergic T cells with dendritic cells (DCs) from patients with ITP. Results:,Our studies demonstrated that the anergized GP-specific T cells have profound effects on both GP-specific T-cell proliferation and antibody production. These anergic T cells exerted their suppressive effects mainly in a cell contact-dependent manner, and they were not constitutively suppressive but required specific antigen stimulation to make DCs tolerogenic. The anergic T-cell-modulated DCs could induce the autoreactive T cells to be tolerant, and this effect was not restricted to T cells of the same specificity. Conclusion:,Our studies demonstrate the efficacy of CTLA4-Ig in suppressing the pathologic autoimmune responses in ITP. These findings provide new insights into the underlying mechanisms of anergy induction in chronic ITP. [source] Culturing in vitro produced blastocysts in sequential media promotes ES cell derivationMOLECULAR REPRODUCTION & DEVELOPMENT, Issue 8 2006J. Liu Abstract Embryonic stem (ES) cell lines are routinely derived from in vivo produced blastocysts. We investigated the efficiency of ES cells derivation from in vitro produced blastocysts either in monoculture or sequential culture. Zygotes from hybrid F1 B6D2 mice were cultured in vitro to the blastocyst stage in Potassium (K+) simplex optimised medium (KSOM) throughout or in KSOM and switched to COOK blastocyst medium on day 3 (KSOM,CBM). Blastocysts were explanted on a feeder layer of mitomycin C-inactivated murine embryonic fibroblasts (MEF) in TX-WES medium for ES cell derivation. Sequential KSOM,CBM resulted in improved blastocyst formation compared to KSOM monoculture. ES cells were obtained from 32.1% of explanted blastocsyts cultured in KSOM,CBM versus18.4% in KSOM alone. ES cell lines were characterized by morphology, expression of SSEA-1, Oct-4 and alkaline phosphatase activity, and normal karyotype. These results indicate that in vitro culture systems to produce blastocysts can influence the efficiency of ES cell line derivation. Mol. Reprod. Dev. 1017,1021, 2006. © 2006 Wiley-Liss, Inc. [source] Rac and Rho: The Story Behind Melanocyte Dendrite FormationPIGMENT CELL & MELANOMA RESEARCH, Issue 5 2002Glynis Scott Melanocyte dendrites are hormonally responsive actin and microtubule containing structures whose primary purpose is to transport melanosomes to the dendrite tip. Melanocyte dendrites have been an area of intense interest for melanocyte biologists, but it was not until recently that we began to understand the mechanisms underlying their formation. In contrast with melanogenesis, for which numerous mutations in pigment producing genes and mouse models have been identified, a genetic defect resulting in impaired dendrite formation has not been found. Therefore, much of the insight into melanocyte dendrites has come from electron microscopy or in vitro culture systems of normal human and murine melanocytes as well as melanoma cell lines. The growth factors that regulate the formation of melanocyte dendrites have been thoroughly studied and it is clear that multiple signalling systems are able to stimulate, and in some cases inhibit, dendrite formation. Recent data points to the Rho family of small guanosine triphosphate (GTP)-binding proteins as master regulators of dendrite formation, particularly Rac and Rho. In this review I will summarize the progress scientists have made in understanding the structure, hormonal regulation and molecular mediators of melanocyte dendrite formation. [source] | |||||||||||||