Browsing by Author "Huang, Yu-Shan"

Now showing 1 - 8 of 8

A fusion protein with the receptor binding domain of vascular endothelial growth factor-A (VEGF-A) is an antagonist of angiogenesis in cancer treatment
(2010-11-01)
Tseng, Feng-Jen
;
Chen, Yu-Cheng
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Lin, Yu-Ling
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Tsai, Nu-Man
;
Lee, Ru-Ping
Vascular endothelial growth factor (VEGF) is an angiogenic factor that signals through VEGFR-1 and VEGFR-2, which are expressed preferentially in proliferating endothelial cells. Thus, simultaneous blockage of both VEGF receptors may provide a more efficient therapeutic response in cancer treatment. We created a recombinant fusion protein (RBDV-IgG1 Fc), which is composed of the receptor binding domain of human VEGF-A (residues 8-109) and the Fc region of human IgG1 immunoglobulin. The recombinant protein can bind to both mouse VEGFR-1 and VEGFR-2 to decrease VEGF-induced proliferation and tube formation of endothelial cells in vitro. In this study, the RBDV-IgG1 Fc fusion protein reduced the effects of proliferation, migration and tube formation induced by VEGF in murine endothelial cells in vitro. In vivo tumor therapy with RBDV-IgG1 Fc resulted in tumor inhibition by reducing angiogenesis. Pathological evidence also shows that RBDV-IgG1 Fc can seriously damage vessels, causing the death of tumor cells. These findings suggest that this chimeric protein has potential as an angiogenesis antagonist in tumor therapy.
Anomalous SAXS for the morphology and metal content of a metallothionein in a metal-atom replacement
(2008-01-01)
Jeng, U-Ser
;
Li, Meiyi
;
Hsu, I-Jui
;
Huang, Yu-Shan
;
Wu, YewChung Sermon
Characterizing the polymeric status of Helicobacter pylori heat shock protein 60
(2009-10-16)
Lin, Ching-Yi
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Huang, Yu-Shan
;
Li, Chi-Han
;
Hsieh, Yuan-Ting
;
Tsai, Nu-Man
Helicobacter pylori heat shock protein 60 (HpHsp60) was first identified as an adhesion molecule associated with H. pylori infection. Here we have analyzed the structure of HpHsp60 via amino acid BLAST, circular dichroism, and electrophoresis and the results indicate that most recombinant HpHsp60 molecules exist as dimers or tetramers, which is quite different from Escherichia coli Hsp60. Treatment of human monocytic cells THP-1 with HpHsp60 was found to up-regulate a panel of cytokines including IL-1 alpha, IL-8, IL-10, IFN-gamma, TNF-alpha, TGF-beta, GRO, and RANTES. Carboxymethylated HpHsp60 molecules with a switched oligomeric status were able to further enhance NF-kappa B-mediated IL-8 and TNF-alpha secretion in THP-1 cells compared to unmodified HpHsp60 molecules. These results indicated that the oligomeric status of HpHsp60s might have an important role in regulating host inflammation and thus help facilitate H. pylori persistent infection. (C) 2009 Elsevier Inc. All rights reserved.
Habituation of Steady-State Visual Evoked Potentials in response to High-Frequency Polychromatic Foveal Visual Stimulation
(2013)
Kuo, Heng-Yuan
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Chiu, George C.
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Zao, John K.
;
Lai, Kuan-Lin
;
Gruber, Allen
In an attempt to develop safe and robust methods for monitoring migraineurs\' brain states, we explores the feasibility of using white, red, green and blue LED lights flickering around their critical flicker fusion (CFF) frequencies as foveal visual stimuli for inducing steady-state visual evoked potentials (SSVEP) and causing discernible habituation trends. After comparing the habituation indices, the multi-scale entropies and the time dependent intrinsic correlations of their SSVEP signals, we reached a tentative conclusion that sharp red and white light pulses flickering barely above their CFF frequencies can replace commonly used 13Hz stimuli to effectively cause SSVEP habituation among normal subjects. Empirical results showed that consecutive short bursts of light can produce more consistent responses than a single prolonged stimulation. Since these high frequency stimuli do not run the risk of triggering migraine or seizure attacks, further tests of these stimuli on migraine patients are warranted in order to verify their effectiveness.
Intrinsic coordination for revealing local structural changes in protein folding-unfolding
(2016-01-28)
Shiu, Ying-Jen
;
Hayashi, Michitoshi
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Shih, Orion
;
Su, Charlene
;
Tsai, Min-Yeh
With a deformed object of a rigid rod inside, the local dislocations may be tracked relatively easily with respect to the internal rigid rod. We apply this concept on protein folding-unfolding to track the internal structural changes of an unfolded protein in solution. Proposed here is a protein internal coordination based on the major axis X of an ellipsoidal protein and the stable intrinsic transition dipole moment mu of the protein during unfolding. In this methodology, small-angle X-ray scattering (SAXS) is used to provide the protein global morphologies in the native and unfolded states. Furthermore, time-resolved fluorescence anisotropy (TRFA) provides the relative orientation between X and mu of Trp59 of the model protein cytochrome c. Hence observed in the protein unfolding with denaturants, acid, urea, or GuHCl, is the elongation of the native protein conformation along a reoriented protein major axis; accompanied are the different extents of relocations of the terminal a helices and loop structures of the protein in the corresponding unfolding.
Resonant X-Ray Scattering and Absorption for the Global and Local Structures of Cu-modified Metallothioneins in Solution
(2009-07-22)
Li, Meiyi
;
Huang, Yu-Shan
;
Jeng, U-Ser
;
Hsu, I-Jui
;
Wu, YewChung Sermon
With Cd and Zn metal ions removed from the native rabbit-liver metallothionein upon unfolding, Cu-modified metallothioneins (Cu-MTs) were obtained during refolding in solutions containing Cu(I) or Cu(II) ions. X-ray absorption near-edge spectroscopic results confirm the respectively assigned oxidation states of the copper ions in Cu(I)-MT and Cu(II)-MT. Global and local structures of the Cu-MTs were subsequently characterized by anomalous small-angle x-ray scattering (ASAXS) and extended x-ray absorption fine structure. Energy-dependent ASAXS results indicate that the morphology of Cu(II)-MT resembles that of the native MT, whereas Cu(I)-MT forms oligomers with a higher copper content. Both dummy-residue simulation and model-shape fitting of the ASAXS data reveal consistently rodlike morphology for Cu(II)-MT. Clearly identified Cu-S, Cu-O, and Cu-Cu contributions in the extended x-ray absorption fine structure analysis indicate that both Cu(I) and Cu(II) ions are bonded with O and S atoms of nearby amino acids in a four-coordination environment, forming metal clusters smaller than metal thiolate clusters in the native MT. It is demonstrated that a combination of resonant x-ray scattering and x-ray absorption can be particularly useful in revealing complementary global and local structures of metalloproteins due to the atom specific characteristics of the two techniques.
Signal Enhancement by Particle Concentration Using Dielectrophoresis in an Electrowetting-driven Droplet
(2012)
Chuo, Tsung-Min
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Hsu, Wensyang
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Huang, Cheng-Yeh
;
Huang, Yu-Shan
;
Chen, Yu-Tong
Signal Enhancement by Particle Concentration Using Dielectrophoresis in an Electrowetting-driven Droplet
(2012-01-01)
Chuo, Tsung-Min
;
Shih, Po-Huai
;
Hsu, Wensyang
;
Huang, Cheng-Yeh
;
Huang, Yu-Shan
This paper describes a new method for enhancing the fluorescence signal of a bead-based immunosensor in a digital microfluidic system by dielectrophoresis (DEP) force. A single droplet containing scattered polystyrene microbeads conjugated with fluorescent dye is first moved by electrowetting to 3-phase spiral electrodes. The fluorescent microbeads are then concentrated by DEP force at 145 VRMS over 100 kHz. It is shown that the proposed microfluidic chip can evidently enhance the fluorescent intensity even there are only very few fluorescent microbeads (10 to 100), where the droplet volume is only 6.25 nanoliter. The total operation time of the concentrating process is less than 3 minutes. The proposed signal enhancement method holds great potential for bead-based immunoassays to have better limit of detection with short analysis time and small sample volume.