Young-Sick Kim

The critical role of mast cell-derived hypoxia-inducible factor-1α in human and mice melanoma growth

Mast cells play an important role in tumorigenesis. Histamine released from mast cells stimulates new vessel formation by acting through the histamine1 (H1) receptor. Despite the evidence of the role of mast cells in tumor growth and angiogenesis, the potential mechanism remains to be elucidated. Therefore, we investigated the role of mast cell‐derived HIF‐1α in melanoma growth. Here, we identify that the most positive cells for HIF‐1α staining are seen in mast cells of human and animal melanoma tissue. The number of the stromal cell types (fibroblasts, macrophages and endothelial cells) was also increased in melanoma tissues. In activated bone marrow‐derived mast cells (BMMCs), expressions of HIF‐1α and VEGF were increased. Histamine also induced the expressions of HIF‐1α and VEGF in BMMCs. H1 receptor antagonists significantly improved overall survival rates and substantially suppressed tumor growth as well as the infiltration of mast cells and levels of VEGF through the inhibition of HIF‐1α expression in B16F10 melanoma‐bearing mice. Furthermore, the injection of HIF‐1α depleted BMMCs markedly inhibited the growth of tumors and migration of mast cells and increased the survival rate of the mice. These findings emphasize that the growth of melanoma can actually be exacerbated by mast cell‐derived HIF‐1α. In aggregate, our results reveal a novel role for mast cell‐derived HIF‐1α in the melanoma microenvironment and have important implications for the design of therapeutic strategies.

Interleukin-32-induced thymic stromal lymphopoietin plays a critical role in macrophage differentiation through the activation of caspase-1 in vitro.

IntroductionInterleukin (IL)-32 is an inflammatory cytokine induced by Mycobacterium tuberculosis and Mycobacterium bovis in a variety of cell types and discovered in the synovial of patients with rheumatoid arthritis (RA). Thymic stromal lymphopoietin (TSLP) play several roles in the pathogenesis of RA. However, the role of IL-32 and TSLP in RA has not been elucidated.MethodsWe evaluated the specific mechanism of between IL-32 and TSLP in RA using human monocyte cell line, THP-1 cells.ResultsHere we documented for the first time that IL-32 highly increased TSLP production in THP-1 cells and human blood monocytes. TSLP expression was induced by IL-32 via activation of caspase-1 and nuclear factor-κB. TSLP produced by IL-32 increased differentiation of monocytes but depletion of TSLP prevented differentiation of monocytes into macrophage-like cells. Chondroprotective drugs such as chondroitin sulfate (CS) and the traditional Korean medicine, BaekJeol-Tang (BT) decrease production of TSLP and activation of caspase-1 and nuclear factor-κB. In addition, CS and BT inhibited IL-32-induced monocytes differentiation.ConclusionsTaken together, IL-32 and TSLP are important cytokines involved in the development of RA. The effects of CS and BT were associated with the downregulation of TSLP and caspase-1 through negative regulation of IL-32 pathways in RA.

Amygdalin suppresses lipopolysaccharide-induced expressions of cyclooxygenase-2 and inducible nitric oxide synthase in mouse BV2 microglial cells

Abstract Background: Amygdalin (D-mandelonitrile-β-D-gentiobioside) is a cynogenic compound found in sweet and bitter almonds, Persicae semen and Armeniacae semen. Amygdalin has been used for the treatment of cancers and for the relief of the pain. We made an aqueous extraction of amygdalin from Armeniacae semen. In this study, the effect of amygdalin on the lipopolysaccharide (LPS)-induced inflammation was investigated. Methods: The effects of amygdalin extracted from Armeniacae semen on the LPS-stimulated mRNA expressions of cyclooxygenase (COX)-1, COX-2 and inducible nitric oxide synthase (iNOS) in the mouse BV2 microglial cells were investigated using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, reverse transcription-polymerase chain reaction (RT-PCR). The effects of amygdalin on the prostaglandins E2 synthesis and the nitric oxide production were also studied by performing prostaglandins E2 immunoassay and by detecting nitric oxide. Results: The present results showed that amygdalin suppressed the prostaglandin E2 synthesis and the nitric oxide production by inhibiting the LPS-stimulated mRNA expressions of COX-2 and iNOS in the mouse BV2 cells. Conclusion: These results show that amygdalin exerts anti-inflammatory and analgesic effects and it dose so probably by suppressing the mRNA expressions of COX-2 and iNOS.

Interband transitions of InAsxSb1−x alloy films

We report pseudodielectric-function spectra from 1.5 to 6.0 eV of InAsxSb1−x ternary alloys obtained by spectroscopic ellipsometry. Energies of the E1, E1+Δ1, E0′, E0′+Δ0′, E2, E2+Δ2, E2′, E2′+Δ2, and E1′ critical points (CPs) were obtained from numerically calculated second derivatives, and identifications established by band-structure calculations using the linear augmented Slater-type orbital method. The E2, E2+Δ2, E2′, and E2′+Δ2 CP structures cross with increasing As-composition. Two saddle-point transitions, Δ5cu-Δ5vu and Δ5cl−Δ5vu, are found for InSb.

Model dielectric functions for AlxGa1−xAs alloys of arbitrary compositions

Many optical models have been used to construct analytic composition-dependent dielectric functions of AlxGa1−xAs alloys. However, these models incorporate various unphysical assumptions to improve their fits to data. Here, we provide the parameters needed to calculate dielectric functions of AlxGa1−xAs for 1.5≤E≤6.0 eV and 0≤x≤1 by means of the parametric model of Johs et al. [Thin Solid Films 313–314, 137 (1998)], which eliminates these problems. A representative example concerning interface analysis is discussed, where it is necessary to construct a dielectric function of an alloy of essentially arbitrary composition.

Inhibitory Effects of BiRyuChe-Bang on Mast Cell-Mediated Allergic Reactions and Inflammatory Cytokines Production

BiRyuChe-bang (BRC) is a Korean prescription medicine, which has been used to treat allergic rhinitis at Kyung Hee Medical Center. In this work, we investigated the effects of BRC on mast cell-mediated allergic reactions and inflammatory cytokines production, and identified the active component of BRC. Histamine release was measured from rat peritoneal mast cells (RPMCs). Ear swelling and passive cutaneous anaphylaxis (PCA) were examined in mouse models. Phorbol 12-myristate 13-acetate (PMA) plus A23187-induced inflammatory cytokines production was measured using enzyme-linked immunosorbent assay. Reverse transcriptase-polymerase chain reaction was used for the expressions of tumor necrosis factor (TNF)-α, interleukin (IL)-6, and IL-8. Activation of nuclear factor (NF)-κB was analyzed by Western blotting. BRC significantly inhibited the compound 48/80-induced ear swelling response, histamine release from RPMCs, PCA activated by anti-dinitrophenyl IgE, and PMA plus A23187-induced inflammatory cytokines production (p < 0.05). In addition, BRC dose-dependently inhibited the mRNA expressions of TNF-α, IL-6, and IL-8 as well as the activation of NF-κB in a human mast cell line, HMC-1 cells. BRC inhibited the levels of TNF-α and IL-6 in mice induced with PCA. Several components of BRC, such as 1,8-Cineole, Linalool, Linalyl acetate, α-Pinene, and α-Terpineol, significantly inhibited the release of histamine from RPMCs (p < 0.05). Among these components, Linalyl acetate was the most effective for inhibiting histamine release. These results indicate that BRC has a potential regulatory effect on allergic and inflammatory reactions mediated by mast cells.

Formation of self-assembled large droplet-epitaxial GaAs islands for the application to reduced reflection

The structural and reflectance properties of large gallium (Ga) droplets and GaAs islands grown by droplet epitaxy (DE) were presented. The reflectance results of self-assembled large GaAs islands by DE suggest the possibility of a novel method for antireflective coating. The diameter, height, density, and aspect ratio of large Ga droplets were investigated up to the scale of optical size. After GaAs island growth, the reflectance of s-polarization at 70° on in-situ measurement was reduced up to approximately 2%–20% in the wavelength range of 350–900 nm. For large GaAs islands, reduction of reflectance for s-, p-polarization at 20°–80° and reduction of reflectance at normal incidence was presented. This result shows that a layer of self-assembled large GaAs islands by DE can be a good candidate for an antireflector for high-quality optoelectronic devices.

Dielectric functions and interband transitions of In1−xAlxSb alloys

Pseudodielectric functions ⟨e⟩ of In1−xAlxSb ternary alloy films were determined from 1.5 to 6.0 eV by spectroscopic ellipsometry. Overlayer effects were minimized by performing in situ chemical etching to more accurately determine intrinsic bulk dielectric responses. Critical-point (CP) energies of structures were determined from numerically calculated second energy derivatives. Where necessary, Brillouin-zone origins were identified by electronic band structure calculations done with the linear augmented Slater-type orbital method. These calculations also showed increasing separation of the E2 and E2′ CP structures with increasing Al-composition

Overlayer effects in the critical-point analysis of ellipsometric spectra: Application to InxGa1−xAs alloys

We investigate the effect of incomplete removal of semiconductor overlayers on critical-point (CP) parameters determined from the analysis of ellipsometric spectra. An approximate analytic expression shows that CP energies and broadening parameters should be relatively unaffected for isolated CPs if the dielectric response of the overlayer varies slowly with energy. The results are confirmed by model calculations for InAs, which show that the energies of the E1 and E1+Δ1 CP structures that are commonly used for compositional analysis of semiconductor alloys are relatively unaffected. We also analyze overlayer-removal data for a series of InxGa1−xAs alloy samples. Consistent with the above, the amplitudes and phases are affected significantly for all CPs, while the energies of the well-separated E1 and E1+Δ1 transitions are relatively invariant. The results show that accurate values of composition can be obtained from the analysis of the E1 and E1+Δ1 CP structures, even if complete removal of overlayers is...

Interband transitions and dielectric functions of InGaSb alloys

We report pseudodielectric functions of In1−xGaxSb ternary alloy films from 1.5 to 6.0 eV determined by spectroscopic ellipsometry. Artifacts were minimized by real-time assessment of overlayer removal, leading to accurate representations of the bulk dielectric responses of these materials. Critical-point (CP) energies were obtained from numerically calculated second energy derivatives, and their Brillouin-zone origins identified by band-structure calculations. The E2′ and E2 + Δ2 CP energies cross with increasing In content as a result of increasing spin-orbit splitting Δ2.