Browsing by Author "Chu, Pei-Yu"

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Measurement of Poly(ethylene glycol) by Cell-Based Anti-poly(ethylene glycol) ELISA
(2010-03-15)
Chuang, Kuo-Hsiang
;
Tzou, Shey-Cherng
;
Cheng, Ta-Chun
;
Kao, Chien-Han
;
Tseng, Wei-Lung
Poly(ethylene glycol) (PEG) is increasingly used in clinical and experimental medicine. However, quantification of PEG and PEGylated small molecules remains laborious and unsatisfactory. In this report, we stably expressed a functional anti-PEG antibody on the surface of BALB 3T3 cells (3T3/alpha PEG cells) to develop a competitive enzyme-linked immunosorbent assay (ELISA) for PEG quantification. The alpha-PEG cell-coated plate bound biotinylated PEG(5K) (CH(3)-PEG(5K)-biotin) and CH(3)-PEG(5K)-(131)I more effectively than did a traditional anti-PEG antibody-coated plate. Competitive binding between PEG (2, 5, 10, or 20 kDa) and a known amount of CH(3)-PEG(5K)-biotin allowed construction of a reproducible competition curve. The alpha PEG cell-based competition ELISA measured small molecules derivatized by PEG(2K), PEG(5K), PEG(10K), PEG(20K), and PEG(5K) at concentrations as low as 58.6, 14.6, 3.7, 3.7, and 14.6 ng/mL respectively. Notably, the presence of serum or bovine serum albumin enhanced PEG measurement by the alpha PEG cell-based competition ELISA. Finally, we show here that the alpha PEG cell-based competition ELISA accurately delineated the pharmacokinetics of PEG(5K), comparable to those determined by direct measurement of radioactivity in blood after intravenous injection of CH(3)-PEG(5K)-(131)I into mice. This quantitative strategy may provide a simple and sensitive method for quantifying PEG and PEGylated small molecules in vivo.
The Imaging Behavior of an MRI Contrast Agent [Gd(TTDA-BOM)](2-) in a Mice Liver Tumor Model at 3 Tesla
(2010)
Jao, Jo-Chi
;
Lu, Hsiang-Chin
;
Lu, Hsin-Ying
;
Wang, Yun-Ming
;
Liu, Gin-Chung
[Gd(TTDA-BOM)](2-) is a newly developed paramagnetic contrast agent. The aim of this study was to investigate the magnetic resonance imaging (MRI) behavior of [Gd(TTDA-BOM)](2-) in mice with implanted AS-30D (Chang hepatoma ascites, CHA) tumor in liver at a 3T high-field whole-body magnetic resonance (MR) scanner. The high-field MR scanner is expected to have a higher signal-to-noise ratio (SNR). The dynamic MRI studies show that the signal enhancement in liver is larger than that in tumor, so that the contrast-to-noise ratio (CNR) between liver and tumor increases after [Gd(TTDA-BOM)](2-) injection. During one-hour investigation, it was found that [Gd(TTDA-BOM)](2-) could stay in liver up to one hour. On the contrary, [Gd(DTPA)](2-) , a kind of commercial contrast agent, was excreted from liver quickly. Therefore, the CNR between liver and tumor using [Gd(TTDA-BOM)](2-) is larger than that using [Gd(DTPA)](2-) and remains high at least up to one hour. In conclusion, [Gd(TTDA-BOM)](2-) might have good potential for being a hepatobiliary MR contrast agent.