Macrophage-derived foam cell formation elicited by oxidized low-density lipoprotein (oxLDL) is the hallmark of early atherogenesis. Detection of foam cell formation is conventionally practiced by Oil Red O (ORO) staining of lipid-laden macrophages. Other methods include 1,1'-dioctadecyl-3,3,3'3'-tetra-methylindocyanide percholorate (DiI)-labeled oxLDL (DiI-oxLDL) uptake and Nile Red staining. The purpose of the present study is to report an optimized method for assessing foam cell formation in cultured macrophages by ORO staining and DiI-oxLDL uptake. After incubation with oxLDL (50 μg/ml) for 24 h, the macrophages were fixed, stained with ORO for just 1 min, pronounced lipid droplets were clearly observed in more than 90% of the macrophages. To test the in vivo applicability of this method, lesions (or foam cells) of cryosections of aortic sinus or primary mouse peritoneal macrophages from ApoE deficient mice fed a high cholesterol diet were successfully stained. In another set of experiments, treatment of macrophages with DiI-oxLDL (10 μg/ml) for 4 h resulted in significant increase in oxLDL uptake in macrophages as demonstrated by confocol microscopy and flow cytometry. We conclude that the optimized ORO staining and fluorescent labeled oxLDL uptake techniques are very useful for assessing intracellular lipid accumulation in macrophages that are simpler and more rapid than currently used methods.

Nanomaterials synthesized from nanobuilding blocks promise size-dependent properties, associated with individual nanoparticles, together with collective properties of ordered arrays. However, one cannot position nanoparticles at specific locations; rather innovative ways of coaxing these particles to self-assemble must be devised. Conversely, model nanoparticles can be placed in any desired position, which enables a systematic enumeration of nanostructure from model nanobuilding blocks. This is desirable because a list of chemically feasible hypothetical structures will help guide the design of strategies leading to their synthesis. Moreover, the models can help characterize nanostructure, calculate (predict) properties, or simulate processes. Here, we start to formulate and use a simulation strategy to generate atomistic models of nanomaterials, which can, potentially, be synthesized from nanobuilding block precursors. Clearly, this represents a formidable task because the number of ways nanoparticles can be arranged into a superlattice is infinite. Nevertheless, numerical tools are available to help build nanoparticle arrays in a systematic way. Here, we exploit the "rules of crystallography" and position nanoparticles, rather than atoms, at crystallographic sites. Specifically, we explore nanoparticle arrays with cubic, tetragonal, and hexagonal symmetries together with primitive, face centered cubic and body centered cubic nanoparticle "packing". We also explore binary nanoparticle superlattices. The resulting nanomaterials, spanning CeO(2), Ti-doped CeO(2), ZnO, ZnS, MgO, CaO, SrO, and BaO, comprise framework architectures, with cavities interconnected by channels traversing (zero), one, two and three dimensions. The final, fully atomistic models comprise three hierarchical levels of structural complexity: crystal structure, microstructure (i.e., grain boundaries, dislocations), and superlattice structure.

The three-dimensional (3D) faceting morphology of ceria nanoparticles is analysed using transmission electron microscopy (TEM)-based computed tomography on the nanometre scale. A novel tomography mode of electron energy loss spectroscopic imaging using a single energy window for inelastically scattered electrons is introduced and found to be reliable and fast for freestanding nanoparticles. To compare the new tomographic method with other methods, we provide the first comprehensive application of three complementary TEM-based imaging techniques, including bright field TEM and annular dark field specific TEM (STEM). Traditional bright-field TEM tomography is found to be applicable, in spite of obvious artefacts, for crystalline particles of constant composition. However, the safest interpretation is achieved by a combined recording of bright field and spectroscopic images.

Inflammation is a host response to external/internal challenge that leads to the release of a large amount of inflammatory mediators. Prolonged or overactivated inflammation contribute to the pathogenesis of many diseases such as bronchitis, rheumatoid arthritis, and chronic nephritis. 1-3)Macrophages play a critical role in immune reactions and serve as an essential interface between innate and adaptive immunity.4) Lipopolysaccharide (LPS), which is one of the most potent microbial initiators of inflammation, activates several signaling pathways in macrophages by acting on tolllike receptor (TLR)4 to induce the expression of inflammatory gene and the release of mediators/cytokines such as interleukin-1 (IL-1), IL-6, tumor necrosis factor-a (TNF-a), and nitric oxide (NO), all of which are involved in the pathogenesis of many diseases. 5,6) The cytokine TNF-a is a soluble homotrimer of 17 kDa protein subunits secreted primarily by monocytes, macrophages, and T cells in response to endotoxin or other stimuli.7) It is known as a proinflammatory cytokine that possesses a multitude of biological activities linked to septic shock, inflammation, cachexia and cell death.8) Inducible NO synthase (iNOS) expression is significantly induced by LPS or cytokines in a variety of immune cells.9) It catalyzes the oxidative deamination of L-arginine to produce NO, a potential pro-inflammation mediator. Overproduction of NO appears to be linked to tissue damage and organ dysfunction. 10) Cyclooxygenase-2 (COX-2) is another pivotal enzyme in the inflammation process. COX-2 is barely detectable under normal physiological conditions, however, it can be rapidly induced in macrophages by stimuli including cytokines, endotoxin and growth factors. Activated COX-2 converts arachidonic acid to prostanoids (including prostaglandins, prostacyclin and thromboxanes) causing pain, edema, and vasodilation in the inflammation site. 11,12) In these events, the inhibition of excess macrophage activities and the attenuation of the expression of TNF-a, NO and COX-2 should serve as the basis for the potential development of anti-inflammation therapy.The molecular mechanism of LPS-induced macrophage activation has been intensively investigated. Various kinases are involved, including mitogen-activated protein kinases (MAPKs).13) MAPKs are a highly conserved family of serine/ threonine kinases including extracellular signal-regulated kinase (ERK), p38 mitogen-activated protein kinase (p38 MAPK) and c-Jun NH 2 -terminal kinase (JNK). They are all important signaling molecules in the control of cellular responses to outside stimuli.14) It has been demonstrated that the phosphorylation of MAPKs is a critical component of the production of NO and pro-inflammation cytokines in activated macrophages. 15,16) Nuclear factor-kB (NF-kB) is an important transcription factor complex that regulates the expression of many genes that code for mediators involved in immune and inflammatory responses, e.g. iNOS, TNF-a and COX-2.17,18) Therefore, NF-kB has become a logica...

CoPt/Pt multilayer nanowires have been successfully fabricated by a dc electrodeposition technique into anodic aluminium oxide (AAO) templates, and their chemistry and crystal structure characterized at the nanoscale. It was found that each individual multilayered nanowire had a regular periodic structure like bamboo. However, the periodicity of diverse nanowires from the same specimen varied in magnitude. The Pt layers grew to the full width of the AAO template. However, the cobalt-rich layers in each nanowire did not fully fill the template pores during growth, resulting in a repeatably oscillating nanowire diameter. The chemical composition of multilayer nanowires was measured to be (Co72Pt28/Pt)n. Both the Co72Pt28 and Pt layers were polycrystalline, consisting of fcc nanocrystals <5 nm in size. The variable nanowire periodicity and wire diameter will result in variable mechanical strength, resistance and GMR effect.