Browsing by Author "Chang, C. Allen"

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Branched alpha-(1,4) Glucans from Lentinula edodes (L10) in Combination with Radiation Enhance Cytotoxic Effect on Human Lung Adenocarcinoma through the Toll-like Receptor 4 Mediated Induction of THP-1 Differentiation/Activation
(2011-11-23)
Lo, Tiffany Chien-Ting
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Hsu, Feng-Ming
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Chang, C. Allen
;
Cheng, Jason Chia-Hsein
;
生物科技學系
This work investigated the role of structure in the binding of polysaccharides from 10 regionally different strains of Lentinula edodes to Toll-like receptor 4 (TLR-4) on monocytes (THP-1) and the potential effect of this interaction on tumor cell viability. Principal component analysis and multiple linear regression identified arabinose, glucose 1 -> 4 linkage, and molecular weights about 2700 and 534 kDa as the significant determinant factors associated with TLR-4 binding activity. The branched alpha-(1,4)-glucan (L10) had the strongest ability to bind to TLR-4 and induce THP-1 cell differentiation. L10 induction of the THP-1 cell differentiation, superoxide production, and cytokine production followed the TLR-4/MyD88/IKK/NF kappa B pathway. Coculture of irradiated human lung adenocarcinoma A549 cells with L10-activated THP-1 cells resulted in significantly decreased percentage of viable A549 cells from 66 to 37% (p = 0.018), increased levels of superoxide, interleukin-8, and RANTES, and decreased levels of angiogenin and vascular endothelial growth factor. The results indicate that L10-activated monocytes have the potential to boost the antitumor immune response and antitumor activity of radiotherapy.
Dinuclear Lanthanide(III)-m-ODO2A-dimer Macrocyclic Complexes: Solution Speciation, DFT Calculations, Luminescence Properties, and Promoted Nitrophenyl-Phosphate Hydrolysis Rates
(2018-04-25)
Chang, C. Allen
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Lee, Hwa-Yu
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Lin, Syue-Liang
;
Meng, Ching-Ning
;
Wu, Tsung-Ta
Potentiometric speciation studies, mass spectrometry, and DFT calculations helped to predict the various structural possibilities of the dinuclear trivalent lanthanide ion (Ln(III), Ln=La, Eu, Tb, Yb, Y) complexes of a novel macrocyclic ligand, m-ODO2A-dimer (H4L), to correlate with their luminescence properties and the promoted BNPP and HPNP phosphodiester bond hydrolysis reaction rates. The stability constants of the dinuclear Ln(2)(m-ODO2A- dimer) complexes and various hydrolytic species confirmed by mass spectrometry were determined. DFT calculations revealed that the Y2LH-1 and the Y2LH-2 species tended to form structures with the respective closed- and open-form conformations. Luminescence lifetime data for the heterodimetallic TbEuL system confirmed the fluorescence resonance energy transfer from the TbIII to Eu-III ion. The internuclear distance RTbEu values were estimated to be in the range of 9.4-11.3 a ( pH 6.7-10.6), which were comparable to those of the DFT calculated open-form conformations. Multiple linear regression analysis of the kobs data was performed using the equation: k(obs),(corr.)=k(obs) k(obs),(OH)=k(Ln2)LH(M)-(>1) [Ln(2)LH(-1)]broken vertical bar k(Ln2LH-2) [Ln(2)LH(-2)] for the observed Ln(2)L-promoted BNPP/HPNP hydrolysis reactions in solution pH from 7 to 10.5 (Ln=Eu, Yb). The results showed that the second-order rate constants for the Eu2LH-2 and Yb2LH-2 species were about 50-400 times more reactive than the structural analogous Zn-2(m-12N(3)O-dimer) system.
Disposable amperometric immunosensing strips fabricated by Au nanoparticles-modified screen-printed carbon electrodes for the detection of foodborne pathogen Escherichia coli O157 : H7
(2008-07-15)
Lin, Yueh-Hui
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Chen, Sz-Hau
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Chuang, Yao-Chen
;
Lu, Yi-Chen
;
Shen, Thomas Y.
A disposable amperometric immunosensing strip was fabricated for rapid detection of Escherichia coli O157:H7. The method uses an indirect sandwich enzyme-linked immunoassay with double antibodies. Screen-printed carbon electrodes (SPCEs) were framed by commercial silver and carbon inks. For electrochemical characterization the carbon electrodes were coupled with the first E. coli O157:H7-specific antibody, E. coli O157:H7 intact cells and the second E. coli O157:H7-specific antibody conjugated with horseradish peroxidase (HRP). Hydrogen peroxide and ferrocenedicarboxylic acid (FeDC) were used as the substrate for HRP and mediator, respectively, at a potential +300 mV vs. counter/reference electrode. The response current (RC) of the immunosensing strips could be amplified significantly by 13-nm diameter Au nanoparticles (AuNPs) attached to the working electrode. The results show that the combined effects of AuNPs and FeDC enhanced RC by 13.1-fold. The SPCE immunosensing strips were used to detect E. coli O157:H7 specifically. Concentrations of E. coli O157:H7 from 10(2) to 10(7) CFU/ml could be detected. The detection limit was approximately 6 CFU/strip in PBS buffer and 50 CFU/strip in milk. The SPCE modified with AuNPs and FeDC has the potential for further applications and provides the basis for incorporating the method into an integrated system for rapid pathogen detection. (c) 2008 Elsevier B.V. All rights reserved.
Dissociation kinetics of macrocyclic trivalent lanthanide complexes of 1,4,7,10-tetraazacyclododecane-1,7-diacetic acid (DO2A)
(2011)
Lin, Chih-Cheng
;
Chen, Chia-Ling
;
Liu, Kuan-Yu
;
Chang, C. Allen
;
生物科技學系
The [H(+)]-catalyzed dissociation rate constants of several trivalent lanthanide (Ln) complexes of 1,4,7,10-tetraazacyclododecane-1,7-diacetic acid (LnDO2A(+), Ln = La, Pr, Eu, Er and Lu) have been determined in two pH ranges: 3.73-5.11 and 1.75-2.65 at four different temperatures (19-41.0. degrees C) in aqueous media at a constant ionic strength of 0.1 mol dm(-3) (LiClO(4)). For the study in the higher pH range, i.e. pH 3.73-5.11, copper(II) ion was used as the scavenger for the free ligand DO2A in acetate/acetic acid buffer medium. The rates of Ln(III) complex dissociation have been found to be independent of [Cu(2+)] and all the Ln(III) complexes studied show [H(+)]-dependence at low acid concentrations but become [H(+)]-independent at high acid concentrations. Influence of the acetate ion content in the buffer on the dissociation rate has also been investigated and all the complexes exhibit a first-order dependence on [Acetate]. The dissociation reactions follow the rate law: k(obs) = k(Ac)[Acetate] + K' k(lim)[H(+)]/(1 + K'[H(+)]) where k(AC) is the dissociation rate constant for the [Acetate]-dependent pathway, k(lim) is the limiting rate constant, and K' is the equilibrium constant for the reaction LnDO2A(+) + H(+) double left right arrow LnDO2AH(2+). In the lower pH range, i.e. pH 1.75-2.65, the dye indicator, cresol red, was used to monitor the dissociation rate, and all the Ln(III) complexes also show [H(+)]-dependence dissociation pathways but without the rate saturation observed at higher pH range. The dissociation reactions follow the simple rate law: k(obs) = k(H)[H(+)], where k(H) is the dissociation rate constant for the pathway involving monoprotonated species. The absence of an [H(+)]-independent pathway in both pH ranges indicates that LnDO2A(+) complexes are kinetically rather inert. The obtained k(AC) values follow the order: LaDO2A(+) > PrDO2A(+) > EuDO2A(+) > ErDO2A(+) > LuDO2A(+), whereas the k(lim) and k(H) values follow the order: LaDO2A(+) > PrDO2A(+) > ErDO2A(+) > EuDO2A(+) > LuDO2A(+), mostly consistent with their thermodynamic stability order, i.e. the more thermodynamically stable the more kinetically inert. In both pH ranges, activation parameters, Delta H*, Delta S* and Delta G*, for both acetate-dependent and proton-catalyzed dissociation pathways have been obtained for most of the La(III), Pr(III), Eu(III), Er(III) and Lu(III) complexes, from the temperature dependence measurements of the rate constants in the 19-41 degrees C range. An isokinetic (linear) relationship is found between Lambda H* and Lambda S* values, which supports a common reaction mechanism.
Dissociation kinetics of macrocyclic trivalent lanthanide complexes of 1-oxa-4,7,10-triazacyclododecane-4,10-diacetic acid (H(2)ODO2A)
(2014)
Chang, C. Allen
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Lin, Chih-Cheng
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Kuo, Chien-Hung
;
交大名義發表
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生物科技學系
The dissociation rates of LnODO2A(+) complexes (ODO2A(2-) is the deprotonated dianion of the ligand H(2)ODO2A, 1-oxa-4,7,10-triazacyclododecane-4,10-diacetic acid) are all faster than those of the corresponding LnDO2A(+) complexes (DO2A(2-) is the deprotonated dianion of the ligand H(2)DO2A, 1,4,7,10-tetraazacyclododecane- 1,7-diacetic acid), consistent with the fact that LnODO2A(+) complexes are kinetically more labile and thermodynamically less stable than the corresponding LnDO2A(+) complexes, and H(2)ODO2A is not pre-organized for Ln(3+) ion complexation but H(2)DO2A is. The dissociation kinetics of selected trivalent lanthanide (Ln(3+), Ln=La, Pr, Eu, Er, Lu) complexes of the macrocyclic ligand H(2)ODO2A (1-oxa-4,7,10-triazacyclododecane-4,10-diacetic acid), LnODO2A(+), were studied in the [H+] range (0.1-2.4) x 10(-4) M in the temperature range 15-45 degrees C. Excess Cu2+ ions were used as the scavenger for the ligand in acetate-acetic acid buffer medium. The dissociation reactions are independent of [Cu2+] and follow the rate law k(obs) =k(d) + k(AC)[Acetate] + K\'k(lim)[H+]/(1 + K\'[H+]), where k(d), k(AC), and k(lim) are the respective dissociation rate constants for the [H+]-independent, acetate-assisted, and the [H+]-dependent limiting pathways; K\' is the equilibrium constant for the protonation reaction LnODO2A(+) + H+ < > LnODO2AH(2+). The dissociation rates of LnODO2A(+) complexes are all faster than those of the corresponding LnDO2A(+) complexes (DO2A(2-) is the fully deprotonated dianion of the ligand H(2)DO2A, 1,4,7,10-tetrazacyclo-dodecane-1,7- diacetic acid), consistent with the notion that LnODO2A(+) complexes are kinetically more labile and thermodynamically less stable than the corresponding LnDO2A(+) complexes, and H(2)ODO2A is not pre-organized for Ln(3+) ion complexation but H(2)DO2A is.
Effects of Concentration of Some Lanthanide(III) Complexes of 1,7-Bis(carboxymethyl)-1,4,7,10-tetraazacyclododecane on Bis(p-nitrophenyl)-phosphate Hydrolysis
(2009-04-01)
Chang, C. Allen
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Wu, Bo Hong
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Hsiao, Chih-Hsiang
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生物科技學系
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Department of Biological Science and Technology
A detailed study of the effects of the concentration of some lanthanide(III) complexes [LnDO2A(+); DO2A = 1,7-bis(carboxymethyl)-1,4,7,10-tetraazacyclododecane] on the hydrolysis of the phosphodiester bond of the compound BNPP [sodium bis(4-nitrophenyl)phosphate] is reported at 25 degrees C and pH 7.90 (Ln = Eu), 9.35 (Ln = Eu), and 9.90 (Ln = Eu, Er and Yb). The reaction is found to be first order with respect to BNPP concentration at pH 7.90 and 9.35 and to increase to 1.78 +/- 0.09, 1.64 +/- 0.07, and 1.63 +/- 0.09 with respect to [EuDO2A(+)] concentration at pH 7.90, 9.35, and 9.90, respectively, thereby indicating that dinuclear species are involved in the reactions. Similar observations were found for the other two LnDO2A(+) complexes at pH 9.90 [1.63 +/- 0.11 (Er) and 1.49 +/- 0.09 (Yb)]. The k(obs) data obtained by the initial rate method could be fitted to a monomer-dimer reaction model for all LnDO2A(+) complexes at pH 7.90, 9.35, and 9.90 in the [LnDO2A(+)] concentration range 1.0-20.0 mM. The dinuclear species, namely the mono-hydroxo-bridged complexes [Ln(2)(DO2A)(2)(mu-OH)(OH)(H(2)O)(n=1-3)] and the di-hydroxo-bridged complexes [Ln(2)(DO2A)(2)(mu-OH)(OH)(H(2)O)(n=0.2)] are found to be more reactive, with reactivities in the order Eu > Yb > Er. The overall formation constants for [Ln(2)(DO2A)(2)(mu-OH)(OH)(H(2)O)(n)]-BNPP are around 10(4)M(-1). The EuDO2A(+)-promoted BNPP hydrolysis rates are similar to, or up to two orders of magnitude faster than, most of those reported for other lanthanide and transition-metal complexes. ((C) Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)
Glycosyl linkage characteristics and classifications of exo-polysaccharides of some regionally different strains of Lentinula edodes by amplified fragment length polymorphism assay and cluster analysis
(2007-06-05)
Lo, Tiffany Chien Ting
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Kang, Ming Wei
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Wang, Bor Cheh
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Chang, C. Allen
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生物科技學系
We report here the first combined amplified fragment length polymorphism (AFLP) analysis of genomic DNA fingerprinting data and cluster analysis of the exo-polysaccharide glycosyl linkage data of 10 regionally different strains of Lentinula edodes to compare their genetic and structural similarities and differences. In addition, the monosaccharide compositions, molecular weights, glycosyl structural linkages were investigated for the exo-polysaccharides extracted from these different phylogenetic groups of regionally different L. edodes. All exo-polysaccharides had similar molecular weight distribution between 1 x 104 and 3 x 106 Da and the monosaccharide composition analysis revealed the presence of heterogeneous materials containing glucose, mannose, xylose, galactose, fucose, rhamnose and arabinose in different ratios. Among these monosaccharides, the glucose contents are the highest for all but one strain, indicating that glucose probably is the building block of the backbones of these exopolysaccharides. The AFLP assay data helped to classify the 10 L. edodes strains into three distinct genetic groups. Gas chromatographic and mass spectrometric (GC-MS) data revealed five different glycosyl linkage types for these exo-polysaccharides. Most of the exo-polysaccharide backbone structures contain (1 -> 4)-linked-D-glucopyranosyl and (I -> 6)-linked-D-glucopyranosyl moieties. Arabinose 1 -> 4 linkages and mannose 1 -> 2 linkages also exist in all strains. The only differences among these linkages are their monosaccharide compositions leading to different degree of backbone and branch formations. Cluster analyses of the GC-MS data of the exo-polysaccharides of the 10 strains resulted in 10 dendrograms. However, four of the 10 dendrograms were identical and were obtained using the average, Ward and weighted linkage type method of Manhattan distance and using the Ward method of Euclidean distance. The results of cluster analyses were not very much different from that of the AFLP assay and allowed the comparison of genetic and structural similarities and differences. (C) 2007 Elsevier B.V. All rights reserved.
Hydrolysis and DFT structural studies of dinuclear Zn(II) and Cu(II) macrocyclic complexes of m-12N(3)O-dimer and the effect of pH on their promoted HPNP hydrolysis rates
(2016)
Chang, C. Allen
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Wu, Tsung-Ta
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Lee, Hwa-Yu
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生物科技學系
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Department of Biological Science and Technology
The synthesis of the ligand, m-12N(3)O-dimer (1,3-bis(1-oxa-4,7,10-triazacyclododecan-7-yl)methyl)benzene, L), and the stability and hydrolysis constants of its dinuclear Zn(II) and Cu(II) complexes are reported, in addition to the effect of pH on HPNP (2-hydroxypropyl-4-nitrophenylphosphate) hydrolysis reaction rates promoted by these complexes. Various structural possibilities of the [Zn2L] and [Cu2L] hydrolytic species derived from solution equilibrium modeling are predicted from density functional theory (DFT) studies to correlate with the promoted HPNP hydrolysis reaction rates and to establish the structure-function-reactivity relationship. Upon deprotonation [Zn2L(OH)](3+) tends to form a structure with a closed-form conformation where it is not possible for para-isomers. At pH >8, the formation of the closed-form [Zn2L(OH)(2)](2+) and [Zn2L(mu-OH)(OH)(2)](+) species led to faster promoted HPNP hydrolysis rates than the [Zn2L(OH)](3+) species. On the other hand, the observed rates of the Cu2L-promoted HPNP hydrolysis reaction were much slower than those of the [Zn2L]-promoted ones due to formation of the inactive, di-mu-OH- bridged closed-form [Cu2L(mu-OH)(2)](2+) structure at high pH. The effects of solvent molecules and the use of higher DFT computation levels, i.e., M06 and M06-2X, in conjunction with cc-pVDZ and cc-pVTZ basis sets on the DFT-predicted structures for both [Cu(12N(4))(H2O)](2+) and [Zn(12N(3)O)(H2O)(2)](2+) complexes were also evaluated and compared with those using the B3LYP/6-31G* method. [GRAPHICS]
Identification and clinical association of anti-cytokeratin 18 autoantibody in COPD
(2010-02-16)
Kuo, Yung-Bin
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Chang, C. Allen
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Wu, Yao-Kuang
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Hsieh, Meng-Jer
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Tsai, Chung-Hsien
The etiology of chronic obstructive pulmonary disease (COPD) remains unclear. A mechanism involving the autoimmune reaction in the pathogenesis of COPD has been proposed but not confirmed. The aim of this study was to investigate whether serum autoantibodies against pulmonary cellular proteins are present in COPD patients and to identify their autoantigens if possible. Samples from 50 COPD patients and 42 control subjects were studied. Circulating autoantibodies were detected by Western blot. Immunoprecipitation and matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry were used to identify the autoantigens. Autoantibodies against pulmonary cellular antigens were found in the sera of COPD patients. Specifically, an autoantibody against the 45-kDa human cytokeratin 18 protein was found in 76.0% of COPD patients and 23.8% of control subjects (p < 0.001). Furthermore, the cytokeratin 18 autoantibody level was positively correlated with the FEV(1) (L) (p = 0.013) and FEV(1) (%pred.) (p, = 0.043) values observed in COPD patients. This study identified the pulmonary epithelial cytokeratin 18 protein as a COPD-associated autoantigen and found that anti-cytokeratin 18 autoantibodies were prevalent in COPD patients. Our results support the hypothesis that humoral autoimmunity may be involved in the pathogenesis of COPD. (C) 2009 Elsevier B.V. All rights reserved.
Identification of Phospholipid Scramblase 1 as a Biomarker and Determination of Its Prognostic Value for Colorectal Cancer
(2011-01-01)
Kuo, Yung-Bin
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Chan, Chung-Chuan
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Chang, C. Allen
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Fan, Chung-Wei
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Hung, Ray-Ping
The purpose of this study was to examine the expression of phospholipid scramblase 1 (PLSCR1) in tumor tissues and plasma specimens of patients with colorectal cancer (CRC), as well as analyze its association with clinical parameters. The expression levels of PLSCR1 protein in 104 matched CRC and adjacent normal tissue sections and 50 pairs of CRC tissue blocks were determined by use of immunohistochemical and Western blot analyses, respectively. To evaluate the diagnostic potential of PLSCR1, the plasma levels of PLSCR1 were investigated in 111 additional subjects (59 CRC patients and 52 healthy controls) by Western blot. PLSCR1 was overexpressed in malignant adenocarcinoma tissues compared with normal colorectal mucosa (P < 0.001). In addition, the plasma level of PLSCR1 was not only significantly elevated in CRC patients compared with healthy individuals (P < 0.001), but it was also substantially increased in early stage CRC (P < 0.001). Importantly, the overall sensitivity and specificity of PLSCR1 for CRC detection were 80% and 59.6%, respectively. The area under the ROC curve of PLSCR1 for CRC diagnosis is 0.75, which increases to 0.8 if combined with the measurement of carcinoembryonic antigen. Univariate analysis with the Cox regression model revealed that elevated PLSCR1 expression indicated a poor prognosis for CRC, This study showed that PLSCR1 protein levels were significantly elevated in both the cancer tissue and plasma of CRC patients. Moreover, the plasma levels of PLSCR1 were significantly elevated in patients with early stage CRC compared with healthy individuals, suggesting that PLSCR1 might be used as a noninvasive serological diagnostic and prognostic biomarker for CRC. (c) 2011 The Feinstein Institute for Medical Research, www.feinsteininstitute.org Online address: hffp://www.molmed.org doi: 10.2119/molmed.2010.00115
Kinetics of Bis(p-nitrophenyl)phosphate (BNPP) Hydrolysis Reactions with Trivalent Lanthanide Complexes of N-Hydroxyethyl(ethylenediamine)-N,N ', N '-triacetate (HEDTA)
(2009-03-01)
Chang, C. Allen
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Chen, Yu-Ping
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Hsiao, Chih-Hsiang
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生物科技學系
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Department of Biological Science and Technology
Kinetic studies of hydrolysis reactions of BNPP [sodium bis(p-nitrophenyl) phosphate] with trivalent lanthanide (Ln(3+)) complexes of HEDTA [HEDTA = N-hydroxyethyl(ethylenediamine)-N,N',N'-triacetate] were performed at pH 6.96-11.34 and 25 degrees C by a spectrophotometric method and by HPLC analysis. The reaction rates increase with increasing atomic number of lanthanide and solution pH from PrHEDTA to EuHEDTA and then decrease for heavier LnHEDTA complexes. Plots of pseudo-first-order rate constants (k(obs)) vs. pH could be fitted to the equation k(obs) = k(LnL(OH))[LnL](T)/{1+exp-[-2.303(pH-pK(h))]} where K(LnL(OH)) is the rate constant for the reaction of LnHEDTA(OH)(-) with BNPP, K(h) is the hydrolysis constant of LnHEDTA, and [LnL](T) is the total concentration of LnHEDTA. The pK(h) values obtained by the kinetic method are in the range 8.2-10.3 and are similar to those measured by potentiometric methods. At [LnL](T) = 10-70 mM and pH 10.5, most of the observed pseudo-first-order rate constants could be fitted to a simple saturation kinetic model, k(obs) = K(1)K[LnHEDTA(OH)(-)]/[1 + K[LnHEDTA(OH)(-)]}, where K is the equilibrium constant for the formation for LnHEDTA(OH)(-)BNPP and is in the range 2-147 M(-1). The k(1) values are in the range 1.12X10(-5)-2.71 X 10(-3) s(-1). The k(obs) data for TbHEDTA and HoHEDTA were fitted to a quadratic equation. It was observed that the dinuclear species are more reactive. ESI mass spectrometry confirmed that the reaction between BNPP and EuHEDTA is a simple hydrolysis but not a transesterification, presumably because the three inner-sphere coordinated water molecules are far away from the coordinated hydroxyethyl group. Hydrolysis is likely to occur by proton transfer from one inner-sphere coordinated water molecule to the deprotonated ethyl oxide group followed by nucleophilic attack of the resulting hydroxide ion on the bonded BNPP anion, ((C) Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)
Prevalence of Human Papillomavirus Genotypes in Northern Taiwanese Women
(2010-10-01)
Tsao, Kuo-Chien
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Huang, Chung-Guei
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Kuo, Yung-Bin
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Chang, Ting-Chang
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Sun, Chien-Feng
The prevalence of Human Papillomavirus (HPV) in the general population of northern Taiwan is described. A total of 343 consecutive cervical swabs from women visiting the medical center for routine gynecologic care were included. Cervical cell cytology was examined by the Papanicolaou (Pap) test, and a PCR-based hybridization gene chip analysis was used to identify HPV genotypes. The HPV prevalence in the overall population was 32.4%. When divided into two groups according to cytology, 20.9% of women with normal cytology were HPV positive while 75.3% of women with abnormal cytology were HPV positive. Among positive samples, 68.5% were single type infections while 31.5% harbored multiple HPV types. A total of 32 types of HPV were identified; the leading five were HPV16 (5.8%), HPV58 (5.3%), HPV53 (4.1%), HPV52 (3.8%), and HPV18 (2.3%). Our results constitute baseline data and may provide important implications for future prophylactic programs. The relatively high prevalence of HPV 58, 53, and 52 among northern Taiwanese women has important implications for vaccine development. J. Med. Virol. 82:1739-1745, 2010. (C) 2010 Wiley-Liss, Inc.
Reduction of the interferences of biochemicals and hematocrit ratio on the determination of whole blood glucose using multiple screen-printed carbon electrode test strips
(2007-11-01)
Lin, Yueh-Hui
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Shen, Thomas Y.
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Chang, C. Allen
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生物科技學系
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電控工程研究所
A practical approach to reduce the interferences of biochemicals and hematocrit ratio (Hct%) in the determination of whole blood glucose using multiple screen-printed carbon electrode (SPCE) test strips is described. SPCE test strips with and without glucose oxidase [i.e., GOD(+)-SPCEs and GOD(-)-SPCEs] were used and the chronoamperometric currents of test glucose solutions with various spiked uric acid concentrations and Hct% were measured. By establishing the interference relationships between glucose concentrations and uric acid concentrations as well as Hct% values and with appropriate corrections, the whole blood glucose determinations could be made to be more accurate and comparable to those determined by the reference YSI method. Specifically, the use of the Delta I value, i.e., the current difference between GOD(+)-SPCE and GOD(-)-SPCE measurements, would reduce most of the uric acid/biochemical interferences. An interpolation method was also established to correct for the glucose determinations with Hct% interferences. The Hct% corrections using the interpolation method are especially important and necessary for those blood samples with glucose concentrations higher than 110 mg dL(-1) and Hct% values lower than 35%. This approach should also be applicable to other biochemical determinations using similar electrochemical techniques.
The formation stability, hydrolytic behavior, mass spectrometry, DFT study, and luminescence properties of trivalent lanthanide complexes of H(2)ODO2A
(2012)
Chang, C. Allen
;
Wang, I-Fan
;
Lee, Hwa-Yu
;
Meng, Ching-Ning
;
Liu, Kuan-Yu
The trivalent lanthanide complex formation constants (log K-f) of the macrocyclic ligand H(2)ODO2A (4,10-dicarboxymethyl-1-oxa-4,7,10-triazacyclododecane) have been determined by pH titration techniques to be in the range 10.84-12.62 which increase with increasing lanthanide atomic number, and are smaller than those of the corresponding H(2)DO2A (1,7-dicarboxylmethyl-1,4,7,10-tetraazacyclododecane) complexes. The equilibrium formation of the dinuclear hydrolysis species, e.g. Ln(2)(ODO2A)(2)(mu-OH)(+) and Ln(2)(ODO2A)(2)(mu-OH)(2), dominates over the mononuclear species, e.g. LnODO2A(OH) and LnODO2A(OH)(2)(-). Mass spectrometry confirmed the presence of [Eu(ODO2A)](+), [Eu(ODO2A)(OH)+H](+), [Eu-2(ODO2A)(2)(OH2)(2)+H](+), [Eu(ODO2A)(OH)(2)](-) and [Eu-2(ODO2A)(2)(OH2)(3)](-) species at pH > 7. Density function theory (DFT) calculated structures of the EuODO2A(H2O)(3)(+) and EuDO2A(H2O)(3)(+) complexes indicate that three inner-sphere coordinated water molecules are arranged in a meridional configuration, i.e. the 3 water molecules are on the same plane perpendicular to that of the basal N3O or N-4 atoms. However, luminescence lifetime studies reveal that the EuODO2A(+) and TbODO2A(+) complexes have 4.1 and 2.9 inner-sphere coordinated water molecules, respectively, indicating that other equilibrium species are also present for the EuODO2A(+) complex. The respective emission spectral intensities and lifetimes at 615 nm (lambda(ex) = 395 nm) and 544 nm (lambda(ex) = 369 nm) of the EuODO2A(+) and TbODO2A(+) complexes increase with increasing pH, consistent with the formation of mu-OH-bridged dinuclear species at higher pH. Additional DFT calculations show that each Y(III) ion is 8-coordinated in the three possible cis-[Y-2(ODO2A)(2)(mu-OH)(H2O)(2)](+), trans-[Y-2(ODO2A)(2)(mu-OH)(H2O)(2)](+) and [Y-2(ODO2A)(2)(mu-OH)(2)] dinuclear complex structures. The first and the second include 6-coordination by the ligand ODO2A(2-), one by the bridged mu-OH ion and one by a water molecule. The third includes 6-coordination by the ligand ODO2A(2-) and two by the bridged mu-OH ions. The two inner-sphere coordinated water molecules in the cis- and trans-[Y-2(ODO2A)(2)(mu-OH)(H2O)(2)](+) dinuclear complexes are in a staggered conformation with torsional angles of 82.21 degrees and 148.54 degrees, respectively.