2,650 research outputs found
Potential functionality and digestibility of oryzanol as determined using in vitro cell culture models
A mouse lymphatic endothelial cell (SVEC4-10) model and a human intestinal cell (C2BBe1) model in vitro were developed and capable to be used to study antioxidant activity, hypocholesterolemic capability and digestibility of γ-oryzanol. The critical and vital parameters in developing these cell models were the emulsion preparation of hydrophobic compounds for cell models, the consistent management of cell culture, and the selection of cell viability detection methods compatible with the cell lines and the test substances. The results showed that, in some situations, γ-oryzanol could present a more effective antioxidant activity than α-tocopherol, in terms of reducing tert-butyl hydroperoxide promoted oxidative damage on cellular mitochondrial activity. After 1-hour oxidation, cell viability was 81.8% when incubated with γ-oryzanol, compared to 54.5% with the control and 74.6% with α-tocopherol. The three major components of γ-oryzanol, cycloartenyl ferulate, 24-methylene cycloartanyl ferulate and campesteryl ferulate, generally had higher antioxidant activity than γ-oryzanol and among them, 24-methylene cycloartanyl ferulate was found to be relatively more effective and could be more powerful than α-tocopherol. A synergistic antioxidant activity among γ-oryzanol, ferulic acid and α-tocopherol was also found. With regard to the hypocholesterolemic capacity of γ-oryzanol, the results suggested that the intact γ-oryzanol was poorly absorbed by intestinal cells in vitro. Therefore, it was speculated that the effect of γ-oryzanol might take place in the lumen of gastrointestinal tract, possibly by means of reducing the micellar solubility of cholesterol and cholesteryl esters and inhibiting cholesterol esterase-facilitated cholesteryl ester hydrolysis. The results showed that preincubation of cholesterol and γ-oryzanol for six hours significantly reduced the cholesterol uptake into cells. γ-Oryzanol also showed a trend towards inhibition of cholesteryl esterase, which is responsible for hydrolyzing cholesteryl esters to free cholesterol before uptake. The results of in vitro digestibility studies of γ-oryzanol showed that the ester bond of γ-oryzanol, especially campesteryl ferulate and sitosteryl ferulate, was broken down by cholesterol esterase and produced triterpene alcohols or sterols and ferulic acid, which were further degraded. The degradation of γ-oryzanol in the stomach may undergo a different pathway because sterols or triterpene alcohols were also not found after peptic digestion
HSP70s: From Tumor Transformation to Cancer Therapy
Heat shock proteins (HSPs) are a defined set of chaperones for maintaining proper functions of proteins. The HSP70 family, one of the most inducible families in response to stress, protects cells from stress-induced cell death. It has been documented that HSP70s are highly expressed in various types of cancer cells and make the cells resistant to adverse microenvironments, such as hypoxia and glucose starvation, which are common features in malignant progression. Over-expression of HSP70s is thus associated with tumor transformation and eventually results in a decrease of chemotherapy efficacy. Notably, the distribution of HSP70s is deregulated in cancer cells. It has been reported that HSP70s localize distinct organelles or are exported to humoral circulation during cancer development. Either surface or exported HSP70s play danger signals and trigger immune response to destroy the tumor cells. In this review, we lay out recent advances in the HSP70s-mediated cancer diagnosis and therapy. This review would be enlightening for clinical cancer medicine
BCS thermal vacuum of fermionic superfluids and its perturbation theory
The thermal field theory is applied to fermionic superfluids by doubling the
degrees of freedom of the BCS theory. We construct the two-mode states and the
corresponding Bogoliubov transformation to obtain the BCS thermal vacuum. The
expectation values with respect to the BCS thermal vacuum produce the
statistical average of the thermodynamic quantities. The BCS thermal vacuum
allows a quantum-mechanical perturbation theory with the BCS theory serving as
the unperturbed state. We evaluate the leading-order corrections to the order
parameter and other physical quantities from the perturbation theory. A direct
evaluation of the pairing correlation as a function of temperature shows the
pseudogap phenomenon results from the perturbation theory. The BCS thermal
vacuum is shown to be a generalized coherent and squeezed state. The
correspondence between the thermal vacuum and purification of the density
matrix allows a unitary transformation, and we found the geometric phase in the
parameter space associated with the transformation.Comment: 14 pages, 2 figure
Relationship between Crude Oil Prices and Stock Prices of Alternative Energy Companies with Recent Evidence
This paper examines the recent interactive relationships between crude oil prices and stock performances of alternative energy companies. Oil prices and stock index of alternative energy sector are found independent from each other before late 2006. Contrary to existing studies, however, we find significant interdependence between oil prices and stock index of alternative energy industry in the recent years. Since late 2006, oil prices become significantly responsible for the stock performances of alternative energy companies. This finding suggests that the stock market investors of alternative energy sector incorporate oil price shocks into their trading decisions only recently.Crude oil price; Alternative energy; Oil stock index
IsaB Inhibits Autophagic Flux to Promote Host Transmission of Methicillin-Resistant Staphylococcus aureus.
Methicillin-resistant Staphylococcus aureus (MRSA) has emerged as a major nosocomial pathogen that is widespread in both health-care facilities and in the community at large, as a result of direct host-to-host transmission. Several virulence factors are associated with pathogen transmission to naive hosts. Immunodominant surface antigen B (IsaB) is a virulence factor that helps Staphylococcus aureus to evade the host defense system. However, the mechanism of IsaB on host transmissibility remains unclear. We found that IsaB expression was elevated in transmissible MRSA. Wild-type isaB strains inhibited autophagic flux to promote bacterial survival and elicit inflammation in THP-1 cells and mouse skin. MRSA isolates with increased IsaB expression showed decreased autophagic flux, and the MRSA isolate with the lowest IsaB expression showed increased autophagic flux. In addition, recombinant IsaB rescued the virulence of the isaB deletion strain and increased the group A streptococcus (GAS) virulence in vivo. Together, these results reveal that IsaB diminishes autophagic flux, thereby allowing MRSA to evade host degradation. These findings suggest that IsaB is a suitable target for preventing or treating MRSA infection
Construction of Cell–Extracellular Matrix Microenvironments by Conjugating ECM Proteins on Supported Lipid Bilayers
The cell membrane is an organized and fluid structure that modulates cellular activities in response to specific extracellular signals, and maintains the critical communication, integration, and homeostasis between the cytosol and the extracellular matrix (ECM). In recent years, tissue engineering and cell biology research has been rapidly progressed by a remarkable understanding of cell and ECM interfaces. In this review, the design of new biomimetic platforms based on the conjugation of ECM proteins on solid supported lipid bilayers (SLBs) will be summarized. The platforms provide a better system to evaluate cellular responses to specific recognition events, gradient, mechanical property, nanostructures, and inter- and intra-molecular interactions of ECM proteins on a non-fouling and fluid membrane. Moreover, the findings from the molecular interactions and cellular activities will be highlighted to look into the cell-materials mechanisms
Catastrophic Emission of Charges from Near-Extremal Nariai Black Holes
Using the in-out formalism and also the monodromy method, we study the
emission of charges from near-extremal charged Nariai black holes with the
black hole and cosmological horizons close to each other. The emission becomes
catastrophic for a charge with energy greater than its chemical potential,
whose leading exponential factor increases inversely proportional to the
separation of two horizons. This implies that near-extremal Nariai black holes
quickly evaporate through the charge emission and end in the de Sitter space,
in contrast to near-extremal RN-dS black holes that have the
Breitenlohner-Friedman bound below which they become stable against Hawking
radiation and Schwinger effect of charge emission. We illuminate the origin of
the catastrophic emission in the phase-integral formulation by comparing
near-extremal charged Nariai black holes with near-extremal RN-dS black holes.Comment: 15 page
Submandibular Cavernous Hemangiomas with Multiple Phleboliths Masquerading as Sialolithiasis
Vasoformative tumors (almost exclusively hemangiomas) are the most common lesions of the major salivary glands during infancy and early childhood. They are more common in the parotid gland but are particularly rare in the submandibular gland. Changes in blood flow dynamics within hemangiomas result in thrombus formation and phleboliths. Hemangiomas of the salivary glands in adults are histologically unlike those in infants, the former being characteristically of the cavernous variant. Most cavernous hemangiomas require surgery since they do not show a tendency to regress. A case of an adult man with cavernous hemangioma affecting the submandibular salivary gland that clinically simulated sialolithiasis is presented to alert surgeons to the possibility of such a lesion. We describe the clinical course and review the literature
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