Browsing by Author "Lin, HQ"

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    Biodegradability of sol-gel silica microparticles for drug delivery
    (Springer, 2009-01) Finnie, KS; Waller, DJ; Perret, FL; Krause-Heuer, AM; Lin, HQ; Hanna, JV; Barbé, CJ
    The biodegradability of porous sol–gel silica microparticles in physiological buffers has been investigated using a USP4 flow-through dissolution tester. In the open configuration, which most closely models in-vivo conditions, the particles dissolved rapidly at pH 7.4, with a rate dependent on the surface area and media flow rate. In the closed configuration, the fastest dissolving 4 mg silica sample was almost completely dissolved in 100 mL of buffer after 36 h. The initial dissolution rates appeared relatively linear but dropped off as dissolved SiO2 concentrations approached 20–25 ppm. Addition of serum proteins acted to slow dissolution by 20–30%, suggesting a slower degradation in vivo. Silica microparticles administered for controlled release drug delivery would therefore be expected to be eliminated relatively rapidly from the body, depending on the sample size and local fluid flow conditions. © 2009, Springer. The original publication is available at www.springerlink.com
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    Prediction of synergistic antitumour effect of gefitinib and radiation in vitro
    (The International Institute of Anticancer Research, 2011-09-01) Lin, HQ; Meriaty, H; Katsifis, A
    AIM: This study investigated the potential of a series of biomarkers in predicting the interaction of gefitinib and radiation in tumour treatment. MATERIALS AND METHODS: In vitro assays were performed on human skin cancer and melanoma cell lines. The antitumour effect was measured by using the MTT assay. Total and phosphorylated epidermal growth factor receptor (EGFR and pEGFR) levels were determined by cell-based ELISA. RESULTS: Gefitinib and radiation interacted to inhibit tumour cell proliferation in a cell line-dependent manner. Synergism dominated the interaction (76%), followed by additive effect (20%) and a few instances of antagonism (4%). Correlation analyses revealed a significant correlation between the median combination index (CI) and gefitinib IC950), radiation ID(50, gefitinib- or EGF-modulated EGFR and/or pEGFR expression (all p ≤ 0.05). CONCLUSION: A potential role of gefitinib efficacy, radiation efficacy and gefitinib- or EGF-modulated EGFR and/or pEGFR expression in the prediction of interaction between gefitinib and radiation is supported. Copyright © 2011 The International Institute of Anticancer Research.
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    Tumour response to gefitinib is associated with EGF- and gefitinib- but not radiation-modulated EGFR expression
    (International Institute of Anticancer Research, 2010-12-01) Lin, HQ; Katsifis, A; Meriaty, H
    Aim: This study was conducted to explore the relationship between different treatment-modulated EGFR expression and gefitinib sensitivity. Materials and Methods: Gefitinib-sensitive (A431) and -resistant (A375, MALME-3M, and SK-MEL 5) tumour cell lines were treated with epidermal growth factor (EGF), gefitinib or radiation in vitro, and EGFR expression levels were measured by using ELISA. Results: EGF, and gefitinib treatment resulted in significantly higher levels of total and/or phosphorylated EGFR in sensitive than in resistant tumours and this was associated with gefitinib IC50. In contrast, radiation-modulated EGFR expression, both total and phosphorylated, did not correlate with the efficacy of gefitinib. Stimulation of proliferation by EGF was significantly stronger in A431 than in the other three lines, indicating sensitive tumours were more EGFR-dependent than resistant tumours for cell proliferation. Conclusion: These findings imply a potential role of EGF- and gefitinib-modulated EGFR expression in predicting gefitinib sensitivity. © 2010, International Institute of Anticancer Research