Browsing by Author "Chen, Nelson G."

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DIFFERENTIATION OF NEURAL STEM/PROGENITOR CELLS USING LOW-INTENSITY ULTRASOUND
(2014-09-01)
Lee, I-Chi
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Lo, Tsu-Lin
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Young, Tai-Horng
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Li, Yi-Chen
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Chen, Nelson G.
Herein, we report the evaluation of apoptosis, cell differentiation, neurite outgrowth and differentiation of neural stem/progenitor cells (NSPCs) in response to low-intensity ultrasound (LIUS) exposure. NSPCs were cultured under different conditions, with and without LIUS exposure, to evaluate the single and complex effects of LIUS. A lactic dehydrogenase assay revealed that the cell viability of NSPCs was maintained with LIUS exposure at an intensity range from 100 to 500 mW/cm(2). Additionally, in comparison with no LIUS exposure, the cell survival rate was improved with the combination of medium supplemented with nerve growth factor and LIUS exposure. Our results indicate that LIUS exposure promoted NSPC attachment and differentiation on a glass substrate. Neurite outgrowth assays revealed the generation of longer, thicker neurites after LIUS exposure. Furthermore, LIUS stimulation substantially increased the percentage of differentiating neural cells in NSPCs treated with nerve growth factor in comparison with the unstimulated group. The high percentage of differentiated neural cells indicated that LIUS induced neuronal networks denser than those observed in the unstimulated groups. Furthermore, the release of nitric oxide, an important small-molecule neurotransmitter, was significantly upregulated after LIUS exposure. It is therefore reasonable to suggest that LIUS promotes the differentiation of NSPCs into neural cells, induces neurite outgrowth and regulates nitric oxide production; thus, LIUS may be a potential candidate for NSPC induction and neural cell therapy. (E-mail: iclee@mail.cgu.edu.tw or yingchih@gate.sinica.edu.tw) (C) 2014 World Federation for Ultrasound in Medicine & Biology.
ESI MS for Microsized Bioparticles
(2017-12-19)
Ozdemir, Abdil
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Lin, Jung-Lee
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Gulfen, Mustafa
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Lai, Szu-Hsueh
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Hsiao, Chun-Jen
An ESI ion trap mass spectrometer was designed for high-throughput and rapid mass analysis of large bioparticles. Mass calibration of the instrument was performed using commercially available polystyrene (PS) microparticles with a size comparable to cancer cells. Different sites of MCF-7 breast cancer cells (8 to 15 mu m) were used in this study. The masses of different cancer cells were measured. This system allows for the analysis of all types of particles.
Investigation of nanoparticle-assisted ultrasound therapy for treating implanted breast tumors in mice
(2017-01-01)
Kosheleva, Olga
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Lai, Tsung-Ching
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Chan, Yung-Chieh
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Hsiao, Michael
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Ng, Shok-Li
The presence of nanoparticles within an ultrasonic field has been previously shown to cause ultrasound to preferentially destroy cancerous cells over corresponding normal cells. Such treatment, termed nanoparticle-assisted ultrasound therapy (NAUT), has now been applied to subcutaneously implanted tumors in mice. Xenografted tumors were exposed to therapeutic ultrasound, with and without intratumoral injections of nanoparticles over a period of 4 weeks. Post-treatment, tumors that received nanoparticle injections were found to be substantially smaller than controls, suggesting that nanoparticle presence significantly increases the efficacy of ultrasonic treatment of solid tumors.
Recent Advances in Anticancer Activities and Drug Delivery Systems of Tannins
(2017-07-01)
Cai, Yuee
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Zhang, Jinming
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Chen, Nelson G.
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Shi, Zhi
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Qiu, Jiange
Tannins, polyphenols in medicinal plants, have been divided into two groups of hydrolysable and condensed tannins, including gallotannins, ellagitannins, and (-)-epigallocatechin-3-gallate (EGCG). Potent anticancer activities have been observed in tannins (especially EGCG) with multiple mechanisms, such as apoptosis, cell cycle arrest, and inhibition of invasion and metastases. Furthermore, the combinational effects of tannins and anticancer drugs have been demonstrated in this review, including chemoprotective, chemosensitive, and antagonizing effects accompanying with anticancer effect. However, the applications of tannins have been hindered due to their poor liposolubility, low bioavailability, off-taste, and shorter half-life time in human body, such as EGCG, gallic acid, and ellagic acid. To tackle these obstacles, novel drug delivery systems have been employed to deliver tannins with the aim of improving their applications, such as gelatin nanoparticles, micelles, nanogold, liposomes, and so on. In this review, the chemical characteristics, anticancer properties, and drug delivery systems of tannins were discussed with an attempt to provide a systemic reference to promote the development of tannins as anticancer agents. (C) 2016 Wiley Periodicals, Inc.
Selective killing of cancer cells by nanoparticle-assisted ultrasound
(2016-06-14)
Kosheleva, Olga K.
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Lai, Tsung-Ching
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Chen, Nelson G.
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Hsiao, Michael
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Chen, Chung-Hsuan
Background: Intense ultrasound, such as that used for tumor ablation, does not differentiate between cancerous and normal cells. A method combining ultrasound and biocompatible gold or magnetic nanoparticles (NPs) was developed under in vitro conditions using human breast and lung epithelial cells, which causes ultrasound to preferentially destroy cancerous cells. Results: Co-cultures of BEAS-2B normal lung cells and A549 cancerous lung cells labeled with green and red fluorescent proteins, respectively, were treated with focused ultrasound beams with the addition of gold and magnetic nanoparticles. There were significantly more necrotic A549 cells than BEAS-2 cells when gold nanoparticles were added to the culture medium [(50.6 +/- 15.1) vs. (7.4 +/- 2.9) %, respectively, P < 0.01]. This selective damage to cancer cells was also observed for MDA-MB231 breast cancer cells relative to MCF-10A normal breast cells after treatment with magnetic nanoparticles. Conclusions: The data obtained for different cell lines indicate that nanoparticle-assisted ultrasound therapy (NAUT) could be an effective new tool for cancer-specific treatment and could potentially be combined with conventional methods of cancer diagnosis and therapy to further increase the overall cancer cure rate.
Spectrophotometric and thermal stability of agarose-based ultrasonic tissue-mimicking gel
(2019-04-21)
Chen, Heng-Yin
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Chen, Nelson G.
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分子醫學與生物工程研究所
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電機工程學系
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Institute of Molecular Medicine and Bioengineering
Spectrophotometric measurements of a commonly used agarose-based ultrasonic tissue-mimicking gel are reported. In addition, spectral characteristics after heating to different temperatures provide thermostability information. Thermostability of agarose gels has not been previously reported, except in general terms. Gels were produced and cast into 2 mm thick spectrophotometric cuvettes. UV-Vis spectra were recorded after gels were heated to various temperatures. Spectral changes resulting from heating were noted and were largely unchanged with heating to temperatures ranging from 30 to 70 degrees C. Only with heating to 80 degrees C, which is near the melting point of the gel material, do spectra irreversibly change. We show that agarose-based tissue-mimicking gels are largely stable over temperatures relevant to most biomedical ultrasonic studies, including those examining hyperthermia or high-intensity focused ultrasound. Therefore, they likely provide a stable substrate in which to conduct ultrasonic heating studies. In addition, UV-Vis spectrophotometry of this optically opaque material has been demonstrated. Possible additives to this material that would enable the measurement of temperature fields through postexposure sectioning and slicing are subsequently discussed. Published under license by AIP Publishing.
Ultrasound-Enhanced Delivery of an Aptamer-Doxorubicin Conjugate to Breast Cancer Cells
(2019-01-01)
Chang, Ju-Yao
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Ju, Tsai-Kai
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Chen, Nelson G.
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Hsiao, Chun-Jen
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Wang, Chin-Yu
When treating cancer with chemotherapy, serious side effects are caused by the inability of the drug to be solely delivered to the tumor. As a result, a portion of the drug agents is inevitably delivered elsewhere and destroy normal cells. We report the first results on combining ultrasound with an aptamer-doxorubicin conjugate to treat cancer cells. Enhancement of therapeutic effects combined with a reduction in side effects indicates the potential of this approach. Although many studies have noted that ultrasound can enhance drug delivery, ultrasound has not addressed the goal of reducing side effects. To both reduce side effects and enhance the efficiency of killing cancer cells, this study mainly uses a specially targeted aptamer conjugated to the anticancer drug doxorubicin (DOX), which was applied in combination with ultrasound for cancer treatment. We also compared the results between cancer and normal cell lines to explore the targeting effect of the aptamer. Both breast cancer cells (MCF-7) and breast cells (MCF-10A) were used for the experiments. The results show that the aptamer conjugated to an anticancer drug can be used to target cancer cells and ultrasound can enhance drug delivery. This method can significantly reduce the side effects of the anticancer drug and achieve favorable therapeutic effects.
Uniqueness: skews bit occurrence frequencies in randomly generated fingerprint libraries
(2016-08)
Chen, Nelson G.
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分子醫學與生物工程研究所
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Institute of Molecular Medicine and Bioengineering
Requiring that randomly generated chemical fingerprint libraries have unique fingerprints such that no two fingerprints are identical causes a systematic skew in bit occurrence frequencies, the proportion at which specified bits are set. Observed frequencies (O) at which each bit is set within the resulting libraries systematically differ from frequencies at which bits are set at fingerprint generation (E). Observed frequencies systematically skew toward 0.5, with the effect being more pronounced as library size approaches the compound space, which is the total number of unique possible fingerprints given the number of bit positions each fingerprint contains. The effect is quantified for varying library sizes as a fraction of the overall compound space, and for changes in the specified frequency E. The cause and implications for this systematic skew are subsequently discussed. When generating random libraries of chemical fingerprints, the imposition of a uniqueness requirement should either be avoided or taken into account.