Galactosylated surface is an attractive substrate for hepatocyte culture because of the specific interaction between the galactose ligand and the asialoglycoprotein receptor on hepatocytes. In this study, we described a scheme to achieve high density of immobilized galactose ligands on polyethylene terephthalate (PET) surface by first surface-grafting polyacrylic acid on plasma-pretreated PET film under UV irradiation, followed by conjugation of a galactose derivative (1-O-(6'-aminohexyl)-D-galactopyranoside) to the grafted polyacrylic acid chains. A high galactose density of 513 nmol/cm(2) on the PET surface was used in this study to investigate the behavior of cultured hepatocyte. This engineered substrate showed high affinity to fluorescein isothiocyanate-lectin binding. Primary rat hepatocytes, when seeded at a density of 2 x 10(5) cells/cm(2), attached to the galactosylated PET substrate at a similar efficiency compared with collagen-coated substrate. The hepatocytes spontaneously formed aggregates 1 day after cell seeding and showed better maintenance of albumin secretion and urea synthesis functions than those cultured on collagen-coated surface. 相似文献
Summary: Energy‐filtering transmission electron microscopy (EFTEM) was employed for the analysis of polymer‐polymer interfaces. To attain imaging and spectral analyses with a spatial resolution of 10 nm, problems arising in the EFTEM analysis for polymer specimens were investigated. Interfaces in poly(methyl methacrylate)/polystyrene‐co‐polyacrylonitrile random copolymer (PMMA/SAN) bilayer films annealed at different temperatures were analyzed by means of elemental mapping and Image‐EELS on EFTEM and the effect of the annealing temperature on the interfacial structures was also investigated.
Objective: To investigate the expression of steroidogenic acute regulatory protein (StAR) in macrophages and the effects of inflammatory
cytokines on StAR expression.
Methods: The macrophages isolated from ApoE knockout mice and C57BL/6J mice and RAW264.7 cells (a cell line from mouse macrophage.
ATCC Number: TIB-71TM) were cultured in DMEM containing 10% fetal bovine serum. RAW264.7 cells were treated with different inflammatory cytokines
(TNF-α, IFN-γ and TGF-β1) and 8-Br-cAMP, a cAMP analog. RT-PCR and Western blot analysis were applied to evaluate the effects
of inflammatory cytokines on StAR expression.
Results: RT-PCR and Western blot analysis demonstrated the expression of StAR in the macrophages isolated from ApoE knockout mice,
C57BL/6J mice and RAW264.7 cells. Proinflammatory cytokines TNF-α and IFN-γ significantly decreased StAR mRNA and protein
levels in RAW264.7 cells. The inhibition was dose- and time-dependent. In contrast, anti-inflammatory cytokine TGF-β1 increased
StAR mRNA and protein levels. At 1:15 molecular ratio, TGF-β1 blocked the down-regulation of StAR expression mediated by TNF-α.
cAMP also induced StAR expression in RAW264.7 cells. When the cells were co-treated with 8-Br-cAMP and TNF-α, 8-Br-cAMP failed
to induce StAR expression.
Conclusion: Our results provide interesting evidence that inflammatory cytokines regulate StAR expression in macrophages.
Received 12 August 2006; returned for revision 28 September 2006; returned for final revision 28 May 2007; accepted by M.
Katori 22 June 2007 相似文献
Interleukin-2 (IL-2), secreted principally by activated helper T-cells, plays a pivotal role in the generation and regulation
of the immune response. The various biologic functions of IL-2 have been the focus of intensive study over the years and have
been well worked out. By contrast, an understanding of the intracellular signals coupled to the IL-2 receptor and responsible
for mediating IL-2 effects in T-cells is far less developed, and the role that protein kinase C (PKC) may play in the various
cellular responses to IL-2 receptor activation is unclear. In this article we will discuss IL-2, its receptors, and IL-2 signal
transduction in relation to the physiological roles PKC activation may play in IL-2-mediated activation of T-cells and other
hematopoietic cells. 相似文献
We have used a new method of genomic microarray to investigate amplification of oncogenes throughout the genome of glioblastoma multiforme (GBM). Array-based comparative genomic hybridization (array CGH) allows for simultaneous examination of 58 oncogenes/amplicons that are commonly amplified in various human cancers. Amplification of multiple oncogenes in human cancers can be rapidly determined in a single experiment. Tumor DNA and normal control DNA were labeled by nick translation with green- and red-tagged nucleotides, respectively. Instead of hybridizing to normal metaphase chromosomes in conventional comparative genomic hybridization (CGH), the probes of the mixed fluorescent labeled DNA were applied to genomic array templates comprised of P1, PAC, and BAC clones of 58 target oncogenes. The baseline for measuring deviations was established by performing a series of independent array CGH using test and reference DNA made from normal individuals. In the present study, we examined fourteen GBMs (seven cell lines and seven tumours) with CGH and array CGH to reveal the particular oncogenes associated with this cancer. High-level amplifications were identified on the oncogenes/amplicons CDK4, GLI, MYCN, MYC, MDM2, and PDGFRA. The highest frequencies of gains were detected on PIK3CA (64.3%), EGFR (57.1%), CSE1L (57.1%), NRAS (50%), MYCN (42.9%), FGR (35.7%), ESR (35.7%), PGY1 (35.7%), and D17S167 (35.7%). These genes are suggested to be involved in the GBM tumorigenesis. 相似文献
Extrinsic allergic alveolitis and pulmonary sarcoidosis are granulomatous diseases of the lung for which clinical presentation and anatomic site of granuloma formation differ. Extrinsic allergic alveolitis is caused by inhaled antigens, whereas the nature and source of the inciting antigen in sarcoidosis is unknown. To test the hypothesis that the route via which antigen is introduced to the lung contributes to the clinicopathological presentation of pulmonary granulomatous disease, rats immunized with intravenous (i.v.) Corynebacterium parvum were challenged after 2 weeks with either intratracheal (i.t.) or i.v. C. parvum. The granulomatous inflammation elicited by i.t. challenge predominantly involved alveolar spaces and histologically simulated extrinsic allergic alveolitis. In contrast, the inflammation induced by i.v. challenge was characterized by granulomatous angiitis and interstitial inflammation simulating sarcoidosis. Elevations of leukocyte counts and TNF levels in bronchoalveolar fluid, which reflect inflammation in the intra-alveolar compartment, were much more pronounced after i.t. than after i.v. challenge. Tumor necrosis factor, interleukin-6, CC chemokine, CXC chemokine, and adhesion molecule mRNA and protein expression occurred in each model. In conclusion, i.t. or i.v. challenge with C. parvum in sensitized rats caused pulmonary granulomatous inflammation that was histologically similar to human extrinsic allergic alveolitis and sarcoidosis, respectively. Although the soluble and cellular mediators of granulomatous inflammation were qualitatively similar in both disease models, the differing anatomic source of the same antigenic challenge was responsible for differing clinicopathological presentations. 相似文献