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Li G, Liu H, Feng R, Kang TS, Wang W, Ko CN, Wong CY, Ye M, Ma DL, Wan JB, Leung CH. A bioactive ligand-conjugated iridium(III) metal-based complex as a Keap1-Nrf2 protein-protein interaction inhibitor against acetaminophen-induced acute liver injury. Redox Biol 2021; 48:102129. [PMID: 34526248 PMCID: PMC8710994 DOI: 10.1016/j.redox.2021.102129] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2021] [Revised: 08/30/2021] [Accepted: 09/07/2021] [Indexed: 01/04/2023] Open
Abstract
Hepatotoxicity caused by an overdose of acetaminophen (APAP) is the leading reason for acute drug-related liver failure. Nuclear factor erythroid-2-related factor 2 (Nrf2) is a protein that helps to regulate redox homeostasis and coordinate stress responses via binding to the Kelch-like ECH-associated protein 1 (Keap1). Targeting the Keap1-Nrf2 interaction has recently emerged as a potential strategy to alleviate liver injury caused by APAP. Here, we designed and synthesized a number of iridium (III) and rhodium (III) complexes bearing ligands with reported activity against oxidative stress, which is associated with Nrf2 transcriptional activation. The iridium (III) complex 1 bearing a bioactive ligand 2,9-dimethyl-1,10-phenanthroline and 4-chloro-2-phenylquinoline, a derivative of the bioactive ligand 2-phenylquinoline, was identified as a direct small-molecule inhibitor of the Keap1–Nrf2 protein-protein interaction. 1 could stabilize Keap1 protein, upregulate HO-1 and NQO1, and promote Nrf2 nuclear translocation in normal liver cells. Moreover, 1 reversed APAP-induced liver damage by disrupting Keap1–Nrf2 interaction and without inducing organ damage and immunotoxicity in mice. Our study demonstrates the identification of a selective and efficacious antagonist of Keap1–Nrf2 interaction possessed good cellular permeability in cellulo and ideal pharmacokinetic parameters in vivo, and, more importantly, validates the feasibility of conjugating metal complexes with bioactive ligands to generate metal-based drug leads as non-toxic Keap1–Nrf2 interaction inhibitors for treating APAP-induced acute liver injury. 1 reversed APAP-induced liver damage by disrupting Keap1–Nrf2 interaction without inducing organ damage or immunotoxicity. Complex 1 possessed good cellular permeability in cellulo and ideal pharmacokinetic parameters in vivo. Conjugating metal complexes with bioactive ligands opens a novel avenue for the treatment of APAP-induced liver damage.
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Affiliation(s)
- Guodong Li
- State Key Laboratory of Quality Research in Chinese Medicine, Institute of Chinese Medical Sciences, University of Macau, Macao SAR, China
| | - Hao Liu
- Department of Chemistry, Hong Kong Baptist University, Kowloon Tong, Hong Kong SAR, China
| | - Ruibing Feng
- State Key Laboratory of Quality Research in Chinese Medicine, Institute of Chinese Medical Sciences, University of Macau, Macao SAR, China
| | - Tian-Shu Kang
- State Key Laboratory of Quality Research in Chinese Medicine, Institute of Chinese Medical Sciences, University of Macau, Macao SAR, China
| | - Wanhe Wang
- Department of Chemistry, Hong Kong Baptist University, Kowloon Tong, Hong Kong SAR, China; Institute of Medical Research, Northwestern Polytechnical University, Xi'an, Shaanxi, 710072, China
| | - Chung-Nga Ko
- Department of Chemistry, Hong Kong Baptist University, Kowloon Tong, Hong Kong SAR, China
| | - Chun-Yuen Wong
- Department of Chemistry, City University of Hong Kong, Tat Chee Avenue, Hong Kong SAR, China
| | - Min Ye
- State Key Laboratory of Natural and Biomimetic Drugs, School of Pharmaceutical Sciences, Peking University, Beijing, China
| | - Dik-Lung Ma
- Department of Chemistry, Hong Kong Baptist University, Kowloon Tong, Hong Kong SAR, China.
| | - Jian-Bo Wan
- State Key Laboratory of Quality Research in Chinese Medicine, Institute of Chinese Medical Sciences, University of Macau, Macao SAR, China.
| | - Chung-Hang Leung
- State Key Laboratory of Quality Research in Chinese Medicine, Institute of Chinese Medical Sciences, University of Macau, Macao SAR, China; Department of Biomedical Sciences, Faculty of Health Sciences, University of Macau, Macao SAR, China.
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Li G, Henry SA, Liu H, Kang TS, Nao SC, Zhao Y, Wu C, Jin J, Zhang JT, Leung CH, Wai Hong Chan P, Ma DL. A robust photoluminescence screening assay identifies uracil-DNA glycosylase inhibitors against prostate cancer. Chem Sci 2020; 11:1750-1760. [PMID: 34123270 PMCID: PMC8148385 DOI: 10.1039/c9sc05623h] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Many cancers have developed resistance to 5-FU, due to removal by the enzyme uracil-DNA glycosylase (UDG), a type of base excision repair enzyme (BER) that can excise uracil and 5-fluorouracil (5-FU) from DNA. However, the development of UDG inhibitor screening methods, especially for the rapid and efficient screening of natural product/natural product-like compounds, is still limited so far. We developed herein a robust time-resolved photoluminescence method for screening UDG inhibitors, which could significantly improve sensitivity over the screening method based on the conventional steady-state spectroscopy, reducing the substantial fluorescence background interference. As a proof-of-concept, two potential UDG inhibitors were identified from a database of natural products and approved drugs. Co-treatment of these two compounds with 5-FU showed synergistic cytotoxicity, providing the basis for treating drug-resistant cancers. Overall, this method provides an avenue for the rapid screening of small molecule regulators of other BER enzyme activities that can avoid false negatives arising from the background fluorescence. The discovery of UDG inhibitors against prostate cancer by using a robust photoluminescence screening assay that can avoid false negatives arising from the background fluorescence.![]()
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Affiliation(s)
- Guodong Li
- State Key Laboratory of Quality Research in Chinese Medicine, Institute of Chinese Medical Sciences, University of Macau Macau
| | | | - Hao Liu
- Department of Chemistry, Hong Kong Baptist University Kowloon Tong Hong Kong
| | - Tian-Shu Kang
- State Key Laboratory of Quality Research in Chinese Medicine, Institute of Chinese Medical Sciences, University of Macau Macau
| | - Sang-Cuo Nao
- State Key Laboratory of Quality Research in Chinese Medicine, Institute of Chinese Medical Sciences, University of Macau Macau
| | - Yichao Zhao
- School of Chemistry, Monash University Clayton Victoria 3800 Australia
| | - Chun Wu
- Department of Chemistry, Hong Kong Baptist University Kowloon Tong Hong Kong
| | - Jianwen Jin
- School of Chemistry, Monash University Clayton Victoria 3800 Australia
| | - Jia-Tong Zhang
- State Key Laboratory of Quality Research in Chinese Medicine, Institute of Chinese Medical Sciences, University of Macau Macau
| | - Chung-Hang Leung
- State Key Laboratory of Quality Research in Chinese Medicine, Institute of Chinese Medical Sciences, University of Macau Macau
| | - Philip Wai Hong Chan
- Department of Chemistry, University of Warwick Coventry CV4 7AL UK.,School of Chemistry, Monash University Clayton Victoria 3800 Australia
| | - Dik-Lung Ma
- Department of Chemistry, Hong Kong Baptist University Kowloon Tong Hong Kong
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Ma DL, Wong SY, Kang TS, Ng HP, Han QB, Leung CH. Iridium(III)-based chemosensors for the detection of metal ions. Methods 2019; 168:3-17. [DOI: 10.1016/j.ymeth.2019.02.013] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2019] [Accepted: 02/15/2019] [Indexed: 01/10/2023] Open
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Zhang JT, Kang TS, Wong SY, Pei RJ, Ma DL, Leung CH. An iridium(III) complex/G-quadruplex ensemble for detection of ochratoxin A based on long-lifetime luminescent. Anal Biochem 2019; 580:49-55. [PMID: 31194944 DOI: 10.1016/j.ab.2019.06.005] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2019] [Revised: 05/30/2019] [Accepted: 06/04/2019] [Indexed: 01/09/2023]
Abstract
A G-quadruplex-based platform has been developed for the time-resolved monitoring of ochratoxin A (OTA). The simple platform displays good sensitivity for OTA with a detection limit of 40 nM via steady-state emission spectroscopy. Notably, the platform showed a detection limit of 10.8 nM via time-resolved emission spectroscopy (TRES), which is about 4 times more sensitive than steady-state mode. Moreover, the probe showed excellent selectivity for OTA over other mycotoxins. Furthermore, OTA was successfully detected in actual herbal plant extracts samples. Our platform is the first to detect OTA using TRES to distinguish between the target signals versus the auto-fluorescence of real samples. This platform shows improved detection speed, accuracy and sensitivity with simple operation, low cost, and no requirement for complicated pre-processing.
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Affiliation(s)
- Jia-Tong Zhang
- State Key Laboratory of Quality Research in Chinese Medicine, Institute of Chinese Medical Sciences, University of Macau, 999078, Macao
| | - Tian-Shu Kang
- State Key Laboratory of Quality Research in Chinese Medicine, Institute of Chinese Medical Sciences, University of Macau, 999078, Macao
| | - Suk-Yu Wong
- Department of Chemistry, Hong Kong Baptist University, Kowloon Tong, 999077, Hong Kong
| | - Ren-Jun Pei
- CAS Key Laboratory for Nano-Bio Interface, Division of Nanobiomedicine, Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences, Suzhou, 215123, China.
| | - Dik-Lung Ma
- Department of Chemistry, Hong Kong Baptist University, Kowloon Tong, 999077, Hong Kong.
| | - Chung-Hang Leung
- State Key Laboratory of Quality Research in Chinese Medicine, Institute of Chinese Medical Sciences, University of Macau, 999078, Macao.
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Kang TS, Ko CN, Zhang JT, Wu C, Wong CY, Ma DL, Leung CH. Rhodium(III)-Based Inhibitor of the JMJD3-H3K27me3 Interaction and Modulator of the Inflammatory Response. Inorg Chem 2018; 57:14023-14026. [DOI: 10.1021/acs.inorgchem.8b02256] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Affiliation(s)
- Tian-Shu Kang
- State Key Laboratory of Quality Research in Chinese Medicine, Institute of Chinese Medical Sciences, University of Macau, Macao 519020, China
| | - Chung-Nga Ko
- Department of Chemistry, Hong Kong Baptist University, Kowloon Tong, Hong Kong 518000, China
| | - Jia-Tong Zhang
- State Key Laboratory of Quality Research in Chinese Medicine, Institute of Chinese Medical Sciences, University of Macau, Macao 519020, China
| | - Chun Wu
- Department of Chemistry, Hong Kong Baptist University, Kowloon Tong, Hong Kong 518000, China
| | - Chun-Yuen Wong
- Department of Chemistry, City University of Hong Kong, Tat Chee Avenue, Hong Kong 518000, China
| | - Dik-Lung Ma
- Department of Chemistry, Hong Kong Baptist University, Kowloon Tong, Hong Kong 518000, China
| | - Chung-Hang Leung
- State Key Laboratory of Quality Research in Chinese Medicine, Institute of Chinese Medical Sciences, University of Macau, Macao 519020, China
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Ng SW, Chung LH, Yeung CF, Lo HS, Shek HL, Kang TS, Leung CH, Ma DL, Wong CY. Frontispiece: Metalated Chromene and Chromone Complexes: pH Switchable Metal-Carbon Bonding Interaction, Photo-triggerable Chromone Delivery Application, and Antioxidative Activity. Chemistry 2018. [DOI: 10.1002/chem.201880864] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- Sze-Wing Ng
- Department of Chemistry; City University of Hong Kong; Tat Chee Avenue Hong Kong SAR P.R. China
- State Key Laboratory of Millimeter Waves; City University of Hong Kong; Tat Chee Avenue, Kowloon Hong Kong SAR P.R. China
| | - Lai-Hon Chung
- Department of Chemistry; City University of Hong Kong; Tat Chee Avenue Hong Kong SAR P.R. China
| | - Chi-Fung Yeung
- Department of Chemistry; City University of Hong Kong; Tat Chee Avenue Hong Kong SAR P.R. China
- State Key Laboratory of Millimeter Waves; City University of Hong Kong; Tat Chee Avenue, Kowloon Hong Kong SAR P.R. China
- Shenzhen Research Institute; City University of Hong Kong; Shenzhen 518057 P. R. China
| | - Hoi-Shing Lo
- Department of Chemistry; City University of Hong Kong; Tat Chee Avenue Hong Kong SAR P.R. China
- Shenzhen Research Institute; City University of Hong Kong; Shenzhen 518057 P. R. China
| | - Hau-Lam Shek
- Department of Chemistry; City University of Hong Kong; Tat Chee Avenue Hong Kong SAR P.R. China
| | - Tian-Shu Kang
- State Key Laboratory of Quality Research in Chinese Medicine; Institute of Chinese Medical Sciences; University of Macau; Macao P.R. China
| | - Chung-Hang Leung
- State Key Laboratory of Quality Research in Chinese Medicine; Institute of Chinese Medical Sciences; University of Macau; Macao P.R. China
| | - Dik-Lung Ma
- Department of Chemistry; Hong Kong Baptist University, Kowloon Tong; Hong Kong SAR P.R. China
| | - Chun-Yuen Wong
- Department of Chemistry; City University of Hong Kong; Tat Chee Avenue Hong Kong SAR P.R. China
- State Key Laboratory of Millimeter Waves; City University of Hong Kong; Tat Chee Avenue, Kowloon Hong Kong SAR P.R. China
- Shenzhen Research Institute; City University of Hong Kong; Shenzhen 518057 P. R. China
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Kang TS, Zhang JT, Vellaisamy K, Ma DL, Leung CH. Recent progress and developments of iridium-based compounds as probes for environmental analytes. Dalton Trans 2018; 47:13314-13317. [DOI: 10.1039/c8dt01167b] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Metal complexes based on iridium metal centers have attracted attention as probes due to their tunable biological and chemical characteristics.
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Affiliation(s)
- Tian-Shu Kang
- State Key Laboratory of Quality Research in Chinese Medicine
- Institute of Chinese Medical Sciences
- University of Macau
- Macao
- China
| | - Jia-Tong Zhang
- State Key Laboratory of Quality Research in Chinese Medicine
- Institute of Chinese Medical Sciences
- University of Macau
- Macao
- China
| | | | - Dik-Lung Ma
- Department of Chemistry
- Hong Kong Baptist University
- Hong Kong
- China
| | - Chung-Hang Leung
- State Key Laboratory of Quality Research in Chinese Medicine
- Institute of Chinese Medical Sciences
- University of Macau
- Macao
- China
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Ng SW, Chung LH, Yeung CF, Lo HS, Shek HL, Kang TS, Leung CH, Ma DL, Wong CY. Metalated Chromene and Chromone Complexes: pH Switchable Metal-Carbon Bonding Interaction, Photo-triggerable Chromone Delivery Application, and Antioxidative Activity. Chemistry 2017; 24:1779-1783. [DOI: 10.1002/chem.201705450] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2017] [Indexed: 12/30/2022]
Affiliation(s)
- Sze-Wing Ng
- Department of Chemistry; City University of Hong Kong; Tat Chee Avenue Hong Kong SAR P.R. China
- State Key Laboratory of Millimeter Waves; City University of Hong Kong; Tat Chee Avenue, Kowloon Hong Kong SAR P.R. China
| | - Lai-Hon Chung
- Department of Chemistry; City University of Hong Kong; Tat Chee Avenue Hong Kong SAR P.R. China
| | - Chi-Fung Yeung
- Department of Chemistry; City University of Hong Kong; Tat Chee Avenue Hong Kong SAR P.R. China
- State Key Laboratory of Millimeter Waves; City University of Hong Kong; Tat Chee Avenue, Kowloon Hong Kong SAR P.R. China
- Shenzhen Research Institute; City University of Hong Kong; Shenzhen 518057 P. R. China
| | - Hoi-Shing Lo
- Department of Chemistry; City University of Hong Kong; Tat Chee Avenue Hong Kong SAR P.R. China
- Shenzhen Research Institute; City University of Hong Kong; Shenzhen 518057 P. R. China
| | - Hau-Lam Shek
- Department of Chemistry; City University of Hong Kong; Tat Chee Avenue Hong Kong SAR P.R. China
| | - Tian-Shu Kang
- State Key Laboratory of Quality Research in Chinese Medicine; Institute of Chinese Medical Sciences; University of Macau; Macao P.R. China
| | - Chung-Hang Leung
- State Key Laboratory of Quality Research in Chinese Medicine; Institute of Chinese Medical Sciences; University of Macau; Macao P.R. China
| | - Dik-Lung Ma
- Department of Chemistry; Hong Kong Baptist University, Kowloon Tong; Hong Kong SAR P.R. China
| | - Chun-Yuen Wong
- Department of Chemistry; City University of Hong Kong; Tat Chee Avenue Hong Kong SAR P.R. China
- State Key Laboratory of Millimeter Waves; City University of Hong Kong; Tat Chee Avenue, Kowloon Hong Kong SAR P.R. China
- Shenzhen Research Institute; City University of Hong Kong; Shenzhen 518057 P. R. China
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Kang TS, Wang W, Zhong HJ, Dong ZZ, Huang Q, Mok SWF, Leung CH, Wong VKW, Ma DL. An anti-prostate cancer benzofuran-conjugated iridium(III) complex as a dual inhibitor of STAT3 and NF-κB. Cancer Lett 2017; 396:76-84. [DOI: 10.1016/j.canlet.2017.03.016] [Citation(s) in RCA: 59] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2016] [Revised: 03/08/2017] [Accepted: 03/09/2017] [Indexed: 01/28/2023]
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Zhong HJ, Wang W, Kang TS, Yan H, Yang Y, Xu L, Wang Y, Ma DL, Leung CH. A Rhodium(III) Complex as an Inhibitor of Neural Precursor Cell Expressed, Developmentally Down-Regulated 8-Activating Enzyme with in Vivo Activity against Inflammatory Bowel Disease. J Med Chem 2016; 60:497-503. [PMID: 27976900 DOI: 10.1021/acs.jmedchem.6b00250] [Citation(s) in RCA: 58] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
We report herein the identification of the rhodium(III) complex [Rh(phq)2(MOPIP)]+ (1) as a potent and selective ATP-competitive neural precursor cell expressed, developmentally down-regulated 8 (NEDD8)-activating enzyme (NAE) inhibitor. Structure-activity relationship analysis indicated that the overall organometallic design of complex 1 was important for anti-inflammatory activity. Complex 1 showed promising anti-inflammatory activity in vivo for the potential treatment of inflammatory bowel disease.
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Affiliation(s)
- Hai-Jing Zhong
- State Key Laboratory of Quality Research in Chinese Medicine, Institute of Chinese Medical Sciences, University of Macau , Taipa, Macao P. R China
| | - Wanhe Wang
- Department of Chemistry, Hong Kong Baptist University , T1303, Cha Chi-Ming Science Tower, Kowloon Tong, Hong Kong, P. R. China
| | - Tian-Shu Kang
- State Key Laboratory of Quality Research in Chinese Medicine, Institute of Chinese Medical Sciences, University of Macau , Taipa, Macao P. R China
| | - Hui Yan
- Institute of New Drug Research and Guangdong Province Key Laboratory of Pharmacodynamic Constituents of Traditional Chinese Medicine, Jinan University College of Pharmacy , Guangzhou 510632, China
| | - Yali Yang
- Institute of New Drug Research and Guangdong Province Key Laboratory of Pharmacodynamic Constituents of Traditional Chinese Medicine, Jinan University College of Pharmacy , Guangzhou 510632, China
| | - Lipeng Xu
- Institute of New Drug Research and Guangdong Province Key Laboratory of Pharmacodynamic Constituents of Traditional Chinese Medicine, Jinan University College of Pharmacy , Guangzhou 510632, China
| | - Yuqiang Wang
- Institute of New Drug Research and Guangdong Province Key Laboratory of Pharmacodynamic Constituents of Traditional Chinese Medicine, Jinan University College of Pharmacy , Guangzhou 510632, China
| | - Dik-Lung Ma
- Department of Chemistry, Hong Kong Baptist University , T1303, Cha Chi-Ming Science Tower, Kowloon Tong, Hong Kong, P. R. China
| | - Chung-Hang Leung
- State Key Laboratory of Quality Research in Chinese Medicine, Institute of Chinese Medical Sciences, University of Macau , Taipa, Macao P. R China
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Lin S, Kang TS, Lu L, Wang W, Ma DL, Leung CH. A G-quadruplex-selective luminescent probe with an anchor tail for the switch-on detection of thymine DNA glycosylase activity. Biosens Bioelectron 2016; 86:849-857. [DOI: 10.1016/j.bios.2016.07.082] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2016] [Revised: 07/23/2016] [Accepted: 07/23/2016] [Indexed: 11/25/2022]
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Lu L, Mao Z, Kang TS, Leung CH, Ma DL. A versatile nanomachine for the sensitive detection of platelet-derived growth factor-BB utilizing a G-quadruplex-selective iridium(III) complex. Biosens Bioelectron 2016; 85:300-309. [DOI: 10.1016/j.bios.2016.05.026] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2016] [Revised: 04/13/2016] [Accepted: 05/02/2016] [Indexed: 12/28/2022]
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Lin S, Lu L, Kang TS, Mergny JL, Leung CH, Ma DL. Interaction of an Iridium(III) Complex with G-Quadruplex DNA and Its Application in Luminescent Switch-On Detection of Siglec-5. Anal Chem 2016; 88:10290-10295. [PMID: 27678199 DOI: 10.1021/acs.analchem.6b03128] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Sialic acid (Sia) binding immunoglobulin (Ig)-like lectin-5 (Siglec-5) is a type-I transmembrane protein, and it has been demonstrated as a biomarker of granulocytic maturation and acute myeloid leukemia phenotype. Herein we aimed to construct a method that could sensitively detect Siglec-5 by taking advantage of the high affinity and selectivity of the K19 aptamer for its cognate target, and the selective interaction of luminescent iridium(III) transition metal complexes with G-quadruplex DNA. The iridium(III) complex 1 [Ir(tpyd)2(2,9-dmphen)]PF6 (where tpyd =2-(m-tolyl)pyridine; 2,9-dmphen =2,9-dimethyl-1,10-phenanthroline) was synthesized, and it displayed high luminescence for G-quadruplex DNA compared to dsDNA and ssDNA. Additionally, complex 1 exhibited a blue shift luminescence response to c-kit2 G-quadruplex, and the interaction between 1 and G-quadruplexes was discussed based on the results of G-tetrad assay, loop effect assay, and other assays. Then complex 1 was utilized to develop a G-quadruplex-based sensing platform for Siglec-5 in aqueous solution. Upon the addition of Siglec-5, the specific binding of the K19 aptamer sequence results in a conformational change that generates a split G-quadruplex structure, which is then recognized by the G-quadruplex-specific iridium(III) complex with an enhanced luminescent response. Futhermore, the use of the assay for detecting Siglec-5 in cellular debris was demonstrated.
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Affiliation(s)
- Sheng Lin
- Department of Chemistry, Hong Kong Baptist University , Kowloon Tong, Hong Kong, China , 999077
| | - Lihua Lu
- Department of Chemistry, Hong Kong Baptist University , Kowloon Tong, Hong Kong, China , 999077.,College of Chemistry and Pharmaceutical Sciences, Qingdao Agricultural University , Qingdao, China , 266109
| | - Tian-Shu Kang
- State Key Laboratory of Quality Research in Chinese Medicine, Institute of Chinese Medical Sciences, University of Macau , Macao, China , 999078
| | - Jean-Louis Mergny
- INSERM, U1212, CNRS, UMR 5320, IECB, Pessac, France , 33607.,University of Bordeaux , ARNA Laboratory, Bordeaux, France , 33370
| | - Chung-Hang Leung
- State Key Laboratory of Quality Research in Chinese Medicine, Institute of Chinese Medical Sciences, University of Macau , Macao, China , 999078
| | - Dik-Lung Ma
- Department of Chemistry, Hong Kong Baptist University , Kowloon Tong, Hong Kong, China , 999077
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Lin S, Lu L, Liu JB, Liu C, Kang TS, Yang C, Leung CH, Ma DL. A G-quadruplex-selective luminescent iridium(III) complex and its application by long lifetime. Biochim Biophys Acta Gen Subj 2016; 1861:1448-1454. [PMID: 27592730 DOI: 10.1016/j.bbagen.2016.08.022] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2016] [Revised: 08/27/2016] [Accepted: 08/30/2016] [Indexed: 01/05/2023]
Abstract
BACKGROUND The G-quadruplex motif has been widely used for the construction of analytical detection platforms due to its rich structural polymorphism and flexibility. Luminescent assays are often limited due to the interference from endogenous fluorophores in biological samples. METHODS To address this challenge, a novel long lifetime iridium(III) complex 1 was synthesized and used to construct a G-quadruplex-based assay for detecting prostate specific antigen (PSA) in aqueous solution. PSA is a common biomarker in serum and used as a model for demonstration in this work. RESULTS The PSA assay has achieved a detection limit of 40.8pg·mL-1, and shows high selectivity towards PSA over other proteins. Additionally, the assay could function in diluted human serum by using time-resolved luminescent spectroscopy, with good linearity from 1 to 10ng·mL-1 of PSA, which is adequate to detect the PSA levels for physiological (<4ng·mL-1) and clinical (4-10ng·mL-1) applications. CONCLUSIONS The assay was successfully constructed. As revealed from time-resolved method, the long lifetime property of iridium(III) complex 1 plays an important role in distinguishing phosphorescence signals from short-life auto-fluorescence of human serum. GENERAL SIGNIFICANCE Luminescent transition metal complexes offer several advantages over other widely used organic fluorophores, such as long phosphorescence lifetime, large Stokes shift and modular syntheses. In addition, the assay could work effectively in diluted human serum using time-resolved luminescent spectroscopy, it therefore could be potentially developed to monitor PSA in biological samples. This article is part of a Special Issue entitled "G-quadruplex" Guest Editor: Dr. Concetta Giancola and Dr. Daniela Montesarchio.
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Affiliation(s)
- Sheng Lin
- Department of Chemistry, Hong Kong Baptist University, Kowloon Tong, Hong Kong, China
| | - Lihua Lu
- Department of Chemistry, Hong Kong Baptist University, Kowloon Tong, Hong Kong, China; College of Chemistry and Pharmaceutical Sciences, Qingdao Agricultural University, Qingdao, China
| | - Jin-Biao Liu
- Department of Chemistry, Hong Kong Baptist University, Kowloon Tong, Hong Kong, China
| | - Chenfu Liu
- Department of Chemistry, Hong Kong Baptist University, Kowloon Tong, Hong Kong, China
| | - Tian-Shu Kang
- State Key Laboratory of Quality Research in Chinese Medicine, Institute of Chinese Medical Sciences, University of Macau, Macao, China
| | - Chao Yang
- State Key Laboratory of Quality Research in Chinese Medicine, Institute of Chinese Medical Sciences, University of Macau, Macao, China
| | - Chung-Hang Leung
- State Key Laboratory of Quality Research in Chinese Medicine, Institute of Chinese Medical Sciences, University of Macau, Macao, China.
| | - Dik-Lung Ma
- Department of Chemistry, Hong Kong Baptist University, Kowloon Tong, Hong Kong, China.
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Kang TS, Mao Z, Ng CT, Wang M, Wang W, Wang C, Lee SMY, Wang Y, Leung CH, Ma DL. Identification of an Iridium(III)-Based Inhibitor of Tumor Necrosis Factor-α. J Med Chem 2016; 59:4026-31. [DOI: 10.1021/acs.jmedchem.6b00112] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Affiliation(s)
- Tian-Shu Kang
- State
Key Laboratory of Quality Research in Chinese Medicine, Institute
of Chinese Medical Sciences, University of Macau, Taipa, Macao, P. R. China
| | - Zhifeng Mao
- Department
of Chemistry, Hong Kong Baptist University, Kowloon Tong, Hong Kong, P. R. China
| | - Chan-Tat Ng
- State
Key Laboratory of Quality Research in Chinese Medicine, Institute
of Chinese Medical Sciences, University of Macau, Taipa, Macao, P. R. China
| | - Modi Wang
- Department
of Chemistry, Hong Kong Baptist University, Kowloon Tong, Hong Kong, P. R. China
| | - Wanhe Wang
- Department
of Chemistry, Hong Kong Baptist University, Kowloon Tong, Hong Kong, P. R. China
| | - Chunming Wang
- State
Key Laboratory of Quality Research in Chinese Medicine, Institute
of Chinese Medical Sciences, University of Macau, Taipa, Macao, P. R. China
| | - Simon Ming-Yuen Lee
- State
Key Laboratory of Quality Research in Chinese Medicine, Institute
of Chinese Medical Sciences, University of Macau, Taipa, Macao, P. R. China
| | - Yitao Wang
- State
Key Laboratory of Quality Research in Chinese Medicine, Institute
of Chinese Medical Sciences, University of Macau, Taipa, Macao, P. R. China
| | - Chung-Hang Leung
- State
Key Laboratory of Quality Research in Chinese Medicine, Institute
of Chinese Medical Sciences, University of Macau, Taipa, Macao, P. R. China
| | - Dik-Lung Ma
- Department
of Chemistry, Hong Kong Baptist University, Kowloon Tong, Hong Kong, P. R. China
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17
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Mao Z, Liu J, Kang TS, Wang W, Han QB, Wang CM, Leung CH, Ma DL. An Ir(III) complex chemosensor for the detection of thiols. Sci Technol Adv Mater 2016; 17:109-114. [PMID: 27877862 PMCID: PMC5101911 DOI: 10.1080/14686996.2016.1162081] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/08/2016] [Revised: 02/26/2016] [Accepted: 03/02/2016] [Indexed: 05/23/2023]
Abstract
In this study, we report the use of a cyclometalated luminescent iridium(III) complex for the visualization of thiols. The detection of glutathione (GSH) by complex 1 is achieved through the reduction of its phendione N^N donor, which influences the metal-to-ligand charge-transfer (MLCT) of the complex. Complex 1 produced a maximum threefold luminescence enhancement at 587 nm in response to GSH. The linear detection range of 1 for GSH is between 0.2 and 2 M equivalents of GSH, with a detection limit of 1.67 μM. Complex 1 also displays good selectivity for thiols over other amino acids.
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Affiliation(s)
- Zhifeng Mao
- Department of Chemistry, Hong Kong Baptist University, Kowloon Tong, Hong Kong, P.R. China
| | - Jinbiao Liu
- Department of Chemistry, Hong Kong Baptist University, Kowloon Tong, Hong Kong, P.R. China
| | - Tian-Shu Kang
- State Key Laboratory of Quality Research in Chinese Medicine, Institute of Chinese Medical Sciences, University of Macau, Macao, P.R. China
| | - Wanhe Wang
- Department of Chemistry, Hong Kong Baptist University, Kowloon Tong, Hong Kong, P.R. China
| | - Quan-Bin Han
- School of Chinese Medicine, Hong Kong Baptist University, Kowloon Tong, Hong Kong, P.R. China
| | - Chun-Ming Wang
- State Key Laboratory of Quality Research in Chinese Medicine, Institute of Chinese Medical Sciences, University of Macau, Macao, P.R. China
| | - Chung-Hang Leung
- State Key Laboratory of Quality Research in Chinese Medicine, Institute of Chinese Medical Sciences, University of Macau, Macao, P.R. China
| | - Dik-Lung Ma
- Department of Chemistry, Hong Kong Baptist University, Kowloon Tong, Hong Kong, P.R. China
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18
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Ma DL, Wang W, Mao Z, Kang TS, Han QB, Chan PWH, Leung CH. Utilization of G-Quadruplex-Forming Aptamers for the Construction of Luminescence Sensing Platforms. Chempluschem 2016; 82:8-17. [DOI: 10.1002/cplu.201600036] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2016] [Revised: 03/07/2016] [Indexed: 01/01/2023]
Affiliation(s)
- Dik-Lung Ma
- Department of Chemistry; Hong Kong Baptist University; 224 Waterloo Road, Kowloon Tong Hong Kong 852 P. R. China
| | - Wanhe Wang
- Department of Chemistry; Hong Kong Baptist University; 224 Waterloo Road, Kowloon Tong Hong Kong 852 P. R. China
| | - Zhifeng Mao
- Department of Chemistry; Hong Kong Baptist University; 224 Waterloo Road, Kowloon Tong Hong Kong 852 P. R. China
| | - Tian-Shu Kang
- State Key Laboratory of Quality Research in Chinese Medicine; Institute of Chinese Medical Sciences; University of Macau; Macao 999078 P. R. China
| | - Quan-Bin Han
- School of Chinese Medicine; Hong Kong Baptist University; Kowloon Hong Kong 852 P. R. China
| | - Philip Wai Hong Chan
- School of Chemistry; Monash University; Clayton VIC 3800 Australia
- Department of Chemistry; University of Warwick; Coventry CV4 7AL United Kingdom
| | - Chung-Hang Leung
- State Key Laboratory of Quality Research in Chinese Medicine; Institute of Chinese Medical Sciences; University of Macau; Macao 999078 P. R. China
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19
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Lu L, Wang M, Mao Z, Kang TS, Chen XP, Lu JJ, Leung CH, Ma DL. A novel dinuclear iridium(III) complex as a G-quadruplex-selective probe for the luminescent switch-on detection of transcription factor HIF-1α. Sci Rep 2016; 6:22458. [PMID: 26932240 PMCID: PMC4773817 DOI: 10.1038/srep22458] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2015] [Accepted: 02/15/2016] [Indexed: 12/18/2022] Open
Abstract
A novel dinuclear Ir(III) complex 5 was discovered to be specific to G-quadruplex DNA, and was utilized in a label-free G-quadruplex-based detection platform for transcription factor activity. The principle of this assay was demonstrated by using HIF-1α as a model protein. Moreover, this HIF-1α detection assay exhibited potential use for biological sample analysis.
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Affiliation(s)
- Lihua Lu
- Department of Chemistry, Hong Kong Baptist University, Kowloon Tong, Hong Kong, China
| | - Modi Wang
- Department of Chemistry, Hong Kong Baptist University, Kowloon Tong, Hong Kong, China
| | - Zhifeng Mao
- Department of Chemistry, Hong Kong Baptist University, Kowloon Tong, Hong Kong, China
| | - Tian-Shu Kang
- State Key Laboratory of Quality Research in Chinese Medicine, Institute of Chinese Medical Sciences, University of Macau, Macao, China
| | - Xiu-Ping Chen
- State Key Laboratory of Quality Research in Chinese Medicine, Institute of Chinese Medical Sciences, University of Macau, Macao, China
| | - Jin-Jian Lu
- State Key Laboratory of Quality Research in Chinese Medicine, Institute of Chinese Medical Sciences, University of Macau, Macao, China
| | - Chung-Hang Leung
- State Key Laboratory of Quality Research in Chinese Medicine, Institute of Chinese Medical Sciences, University of Macau, Macao, China
| | - Dik-Lung Ma
- Department of Chemistry, Hong Kong Baptist University, Kowloon Tong, Hong Kong, China
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20
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Wang M, Mao Z, Kang TS, Wong CY, Mergny JL, Leung CH, Ma DL. Conjugating a groove-binding motif to an Ir(iii) complex for the enhancement of G-quadruplex probe behavior. Chem Sci 2016; 7:2516-2523. [PMID: 28660021 PMCID: PMC5477052 DOI: 10.1039/c6sc00001k] [Citation(s) in RCA: 146] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2016] [Accepted: 01/28/2016] [Indexed: 12/15/2022] Open
Abstract
G-quadruplex groove binder benzo[d,e]isoquinoline was linked to a Ir(iii) complex to generate a highly selective DNA probe.
In this study, the reported G-quadruplex groove binder benzo[d,e]isoquinoline was linked to a cyclometallated Ir(iii) complex to generate a highly selective DNA probe 1 that retains the favorable photophysical properties of the parent complex. The linked complex 1 showed advantages of both parent complex 2 and groove binder 3. Similar to 3, the conjugated complex 1 exhibits a superior affinity and selectivity for G-quadruplex DNA over other conformations of DNA or proteins, with the fold enhancement ratio obviously improved compared with parent complex 2. The molecular modelling revealed a groove-binding mode between complex 1 and G-quadruplex. Meanwhile 1 also possesses the prominent advantages of transition metal complex probes such as a large Stokes shift and long lifetime phosphorescence, which could be recognized in strong fluorescence media through time-resolved emission spectroscopy (TRES). We then employed 1 to develop a detection assay for AGR2, a potential cancer biomarker, as a “proof-of-principle” demonstration of the application of a linked complex for DNA-based detection in diluted fetal bovine serum. We anticipate that this conjugation method may be further employed in the development of DNA probes and have applications in label-free DNA-based diagnostic platforms.
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Affiliation(s)
- Modi Wang
- Department of Chemistry , Hong Kong Baptist University , Kowloon Tong , Hong Kong , China .
| | - Zhifeng Mao
- Department of Chemistry , Hong Kong Baptist University , Kowloon Tong , Hong Kong , China .
| | - Tian-Shu Kang
- State Key Laboratory of Quality Research in Chinese Medicine , Institute of Chinese Medical Sciences , University of Macau , Macao , China .
| | - Chun-Yuen Wong
- Department of Biology and Chemistry , City University of Hong Kong , Kowloon Tong , Hong Kong , China
| | - Jean-Louis Mergny
- University of Bordeaux , ARNA Laboratory , Bordeaux , France . .,INSERM , U869 , IECB , Pessac , France
| | - Chung-Hang Leung
- State Key Laboratory of Quality Research in Chinese Medicine , Institute of Chinese Medical Sciences , University of Macau , Macao , China .
| | - Dik-Lung Ma
- Department of Chemistry , Hong Kong Baptist University , Kowloon Tong , Hong Kong , China .
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21
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Lu L, Wang W, Yang C, Kang TS, Leung CH, Ma DL. Iridium(iii) complexes with 1,10-phenanthroline-based N^N ligands as highly selective luminescent G-quadruplex probes and application for switch-on ribonuclease H detection. J Mater Chem B 2016; 4:6791-6796. [DOI: 10.1039/c6tb02316a] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
A study was performed to investigate the relationship between molecular structure and G4 sensing ability for a series of iridium(iii) complexes. The complex7was used to construct a G4-based assay for RNase H.
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Affiliation(s)
- Lihua Lu
- College of Chemistry and Pharmaceutical Sciences
- Qingdao Agricultural University
- Qingdao 266109
- China
- Department of Chemistry
| | - Wanhe Wang
- Department of Chemistry
- Hong Kong Baptist University
- Hong Kong
- China
| | - Chao Yang
- State Key Laboratory of Quality Research in Chinese Medicine
- Institute of Chinese Medical Sciences
- University of Macau
- Macao
- China
| | - Tian-Shu Kang
- State Key Laboratory of Quality Research in Chinese Medicine
- Institute of Chinese Medical Sciences
- University of Macau
- Macao
- China
| | - Chung-Hang Leung
- State Key Laboratory of Quality Research in Chinese Medicine
- Institute of Chinese Medical Sciences
- University of Macau
- Macao
- China
| | - Dik-Lung Ma
- Department of Chemistry
- Hong Kong Baptist University
- Hong Kong
- China
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22
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Lu L, Wang W, Wang M, Kang TS, Lu JJ, Chen XP, Han QB, Leung CH, Ma DL. A luminescent G-quadruplex-selective iridium(iii) complex for the label-free detection of lysozyme. J Mater Chem B 2016; 4:2407-2411. [DOI: 10.1039/c6tb00426a] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A novel Ir(iii) complex 1 displays high selectivity for the G-quadruplex, and was used to establish a label-free G-quadruplex-based detection platform for lysozyme in buffer.
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Affiliation(s)
- Lihua Lu
- Department of Chemistry
- Hong Kong Baptist University
- Kowloon Tong
- China
| | - Wanhe Wang
- Department of Chemistry
- Hong Kong Baptist University
- Kowloon Tong
- China
| | - Modi Wang
- Department of Chemistry
- Hong Kong Baptist University
- Kowloon Tong
- China
| | - Tian-Shu Kang
- State Key Laboratory of Quality Research in Chinese Medicine
- Institute of Chinese Medical Sciences
- University of Macau
- Macao
- China
| | - Jin-Jian Lu
- State Key Laboratory of Quality Research in Chinese Medicine
- Institute of Chinese Medical Sciences
- University of Macau
- Macao
- China
| | - Xiu-Ping Chen
- State Key Laboratory of Quality Research in Chinese Medicine
- Institute of Chinese Medical Sciences
- University of Macau
- Macao
- China
| | - Quan-Bin Han
- School of Chinese Medicine
- Hong Kong Baptist University
- Kowloon Tong
- China
| | - Chung-Hang Leung
- State Key Laboratory of Quality Research in Chinese Medicine
- Institute of Chinese Medical Sciences
- University of Macau
- Macao
- China
| | - Dik-Lung Ma
- Department of Chemistry
- Hong Kong Baptist University
- Kowloon Tong
- China
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23
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Wang M, Wang W, Kang TS, Leung CH, Ma DL. Development of an Iridium(III) Complex as a G-Quadruplex Probe and Its Application for the G-Quadruplex-Based Luminescent Detection of Picomolar Insulin. Anal Chem 2015; 88:981-7. [DOI: 10.1021/acs.analchem.5b04064] [Citation(s) in RCA: 100] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Affiliation(s)
- Modi Wang
- Department
of Chemistry, Hong Kong Baptist University, Kowloon Tong, Hong Kong, China
| | - Wanhe Wang
- Department
of Chemistry, Hong Kong Baptist University, Kowloon Tong, Hong Kong, China
| | - Tian-Shu Kang
- State
Key Laboratory of Quality Research in Chinese Medicine, Institute
of Chinese Medical Sciences, University of Macau, Macao, China
| | - Chung-Hang Leung
- State
Key Laboratory of Quality Research in Chinese Medicine, Institute
of Chinese Medical Sciences, University of Macau, Macao, China
| | - Dik-Lung Ma
- Department
of Chemistry, Hong Kong Baptist University, Kowloon Tong, Hong Kong, China
- Partner
State Key Laboratory of Environmental and Biological Analysis, Hong Kong Baptist University, Hong Kong, China
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24
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Wang W, Kang TS, Chan PWH, Lu JJ, Chen XP, Leung CH, Ma DL. A label-free G-quadruplex-based mercury detection assay employing the exonuclease III-mediated cleavage of T-Hg 2+-T mismatched DNA. Sci Technol Adv Mater 2015; 16:065004. [PMID: 27877846 PMCID: PMC5069990 DOI: 10.1088/1468-6996/16/6/065004] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/09/2015] [Revised: 11/03/2015] [Accepted: 11/04/2015] [Indexed: 05/30/2023]
Abstract
We report herein the use of an exonuclease III and G-quadruplex probe to construct a G-quadruplex-based luminescence detection platform for Hg2+. Unlike common DNA-based Hg2+ detection methods, when using the dsDNA probe to monitor the hairpin formation, the intercalation of the dsDNA probe may be influenced by the distortion of dsDNA. This 'mix-and-detect' methodology utilized the G-quadruplex probe as the signal transducer and is simple, rapid, convenient to use and can detect down to 20 nM of Hg2+.
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Affiliation(s)
- Wanhe Wang
- Department of Chemistry, Hong Kong Baptist University, Kowloon Tong, Hong Kong, China
| | - Tian-Shu Kang
- State Key Laboratory of Quality Research in Chinese Medicine, Institute of Chinese Medical Sciences, University of Macau, Macao, China
| | - Philip Wai Hong Chan
- School of Chemistry, Monash University, Clayton, Victoria 3800, Australia
- Department of Chemistry, University of Warwick, Coventry CV4 7AL, UK
| | - Jin-Jian Lu
- State Key Laboratory of Quality Research in Chinese Medicine, Institute of Chinese Medical Sciences, University of Macau, Macao, China
| | - Xiu-Ping Chen
- State Key Laboratory of Quality Research in Chinese Medicine, Institute of Chinese Medical Sciences, University of Macau, Macao, China
| | - Chung-Hang Leung
- State Key Laboratory of Quality Research in Chinese Medicine, Institute of Chinese Medical Sciences, University of Macau, Macao, China
| | - Dik-Lung Ma
- Department of Chemistry, Hong Kong Baptist University, Kowloon Tong, Hong Kong, China
- Partner State Key Laboratory of Environmental and Biological Analysis, Hong Kong Baptist University, Hong Kong, China
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25
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Kim DS, Kang C, Kim DH, Kim SC, Lee SH, Jeong JH, Kang TS, Jung SM, Lee SB, Lee KW, Kim RB. External validation of the prognostic index in acute paraquat poisoning. Hum Exp Toxicol 2015; 35:366-70. [PMID: 25977258 DOI: 10.1177/0960327115586821] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
OBJECTIVE Some studies have evaluated the prognostic indicators associated with acute paraquat (PQ) poisoning. In this study, we externally validated the Yamaguchi index, which showed a good prognostic relevance in predicting the outcome of PQ poisoning. METHODS A retrospective analysis of 297 patients was performed. The Yamaguchi index was calculated using the following equation: Eq1 = (K(+) × HCO3(-))/(Creatinine × 0.088)(mEq/L) against time from PQ ingestion (T). The patients were divided into three groups: group A: Eq1 > 1500 - 399 × log T, group B: 930 - 399 × log T < Eq1 ≤ 1500 - 399 × log T, and group C: Eq1 ≤ 930 - 399 × log T). RESULTS The overall mortality rate was 65.3% (194 of 297). The mortality rates of the three groups stratified by the Yamaguchi index were 7.1% (2 of 28), 22.4% (15 of 67), and 87.6% (177 of 202). The area under the receiver-operating characteristic curve for predicting mortality from the external validation of the Yamaguchi index was 0.842 (95% confidence interval: 0.795-0.882). CONCLUSION The Yamaguchi index is a reliable prognostic factor and could be helpful in predicting mortality due to PQ poisoning.
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Affiliation(s)
- D S Kim
- Department of Emergency Medicine, Gyeongsang National University School of Medicine, Jinju, Republic of Korea
| | - C Kang
- Department of Emergency Medicine, Gyeongsang National University School of Medicine, Jinju, Republic of Korea Gyeongsang Institute of Health Sciences, Gyeongsang National University School of Medicine, Jinju, Republic of Korea
| | - D H Kim
- Department of Emergency Medicine, Gyeongsang National University School of Medicine, Jinju, Republic of Korea
| | - S C Kim
- Department of Emergency Medicine, Gyeongsang National University School of Medicine, Jinju, Republic of Korea Gyeongsang Institute of Health Sciences, Gyeongsang National University School of Medicine, Jinju, Republic of Korea
| | - S H Lee
- Department of Emergency Medicine, Gyeongsang National University School of Medicine, Jinju, Republic of Korea Gyeongsang Institute of Health Sciences, Gyeongsang National University School of Medicine, Jinju, Republic of Korea
| | - J H Jeong
- Department of Emergency Medicine, Gyeongsang National University School of Medicine, Jinju, Republic of Korea
| | - T S Kang
- Department of Emergency Medicine, Gyeongsang National University School of Medicine, Jinju, Republic of Korea
| | - S M Jung
- Department of Emergency Medicine, Gyeongsang National University School of Medicine, Jinju, Republic of Korea
| | - S B Lee
- Department of Emergency Medicine, Gyeongsang National University School of Medicine, Jinju, Republic of Korea
| | - K W Lee
- Department of Emergency Medicine, Catholic University of Daegu, Daegu, Republic of Korea
| | - R B Kim
- Department of Preventive Medicine, Dong-A University, Busan, Republic of Korea
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26
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Chen W, Carvalho LPD, Chan MY, Kini RM, Kang TS. Fasxiator, a novel factor XIa inhibitor from snake venom, and its site-specific mutagenesis to improve potency and selectivity. J Thromb Haemost 2015; 13:248-61. [PMID: 25418421 DOI: 10.1111/jth.12797] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2014] [Accepted: 11/11/2014] [Indexed: 02/03/2023]
Abstract
BACKGROUND Bleeding remains a major limitation of standard anticoagulant drugs that target the extrinsic and common coagulation pathways. Recently, intrinsic coagulation factors are increasingly being investigated as alternative targets for developing anticoagulant drugs with lower bleeding risk. OBJECTIVES Goals were to (i) identify novel anticoagulants selectively targeting intrinsic coagulation pathway and (ii) characterize and further improve the properties of the identified anticoagulants. METHODS AND RESULTS We have isolated and sequenced a specific factor XIa (FXIa) inhibitor, henceforth named Fasxiator, from the venom of the banded krait snake, Bungarus fasciatus. It is a Kunitz-type protease inhibitor that prolonged activated partial thromboplastin time without significant effects on prothrombin time. Fasxiator was recombinantly expressed (rFasxiator), purified, and characterized to be a slow-type inhibitor of FXIa that exerts its anticoagulant activities (doubled activated partial thromboplastin time at ~ 3 μmol L(-1) ) by selectively inhibiting human FXIa in in vitro assays. A series of mutants were subsequently generated to improve the potency and selectivity of recombinant rFasxiator. rFasxiatorN17R,L19E showed the best balance between potency (IC50 ~ 1 nmol L(-1) ) and selectivity (> 100 times). rFasxiatorN17R,L19E is a competitive slow-type inhibitor of FXIa (Ki = 0.86 nmol L(-1) ), possesses anticoagulant activity that is ~ 10 times stronger in human plasma than in murine plasma, and prolonged the occlusion time of mice carotid artery in FeCl3 -induced thrombosis models. CONCLUSION We have isolated an exogenous FXIa specific inhibitor, engineered it to improve its potency by ~ 1000 times and demonstrated its in vitro and in vivo efficacy. These proof-of-principle data supported the further development of Fasxiator as a novel anticoagulant candidate.
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Affiliation(s)
- W Chen
- Department of Pharmacy, National University of Singapore, Singapore City, Singapore
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27
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Kang TS, Hong OS, Kim KS, Yoon CS. Hearing among male firefighters: a comparison with hearing data from screened and unscreened male population. J Expo Sci Environ Epidemiol 2015; 25:106-12. [PMID: 25352160 PMCID: PMC4269805 DOI: 10.1038/jes.2014.72] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/19/2014] [Accepted: 08/28/2014] [Indexed: 06/04/2023]
Abstract
We investigated whether hearing loss is associated with firefighting. We conducted cross-sectional study comparing hearing threshold levels (HTLs) of 912 male firefighters with two hearing databases obtained from an otologically normal male Korean population (KONP) and a non-industrial noise-exposed male Korean population (KNINEP), considering age and the main roles of firefighters. Firefighters' age-adjusted HTLs were significantly worse than those of KONP (prevalence ratio (PR)=5.29, P<0.001)but not different from those of KNINEP (PR=0.99, P=0.550). Rescuers (PR=1.005, P<0.001) had worse hearing than the KNINEP after age adjustment. Comparison of firefighters' HTLs (50th and 90th percentiles) with those of KONP and KNINEP by age and frequency showed that firefighters' HTLs had significant increases (poorer hearing) across most age groups and frequencies compared with KONP. Compared with KNINEP, firefighters' HTLs were worse in the younger age groups (<45 years) but not different in the older age groups (>45 years). In conclusion, the hearing thresholds of younger firefighters and rescuers were worse than expected by normal aging alone. Future research should include longitudinal studies to consider variable risk factors, such as military service, smoking, and so on.
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Affiliation(s)
- T S Kang
- Department of Environmental Health and Institute of Health and Environment, Graduate School of Public Health, Seoul National University, Seoul, Korea
| | - O S Hong
- School of Nursing, University of California San Francisco, CA, USA
| | - K S Kim
- Seoul Medical Center, Seoul, Korea
| | - C S Yoon
- Department of Environmental Health and Institute of Health and Environment, Graduate School of Public Health, Seoul National University, Seoul, Korea
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28
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Kang TS, Korber DR, Tanaka T. Glycerol and environmental factors: effects on 1,3-propanediol production and NAD(+) regeneration in Lactobacillus panis PM1. J Appl Microbiol 2013; 115:1003-11. [PMID: 23795775 DOI: 10.1111/jam.12291] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2013] [Revised: 05/22/2013] [Accepted: 06/18/2013] [Indexed: 11/28/2022]
Abstract
AIMS This study was conducted to understand the influences of fermentation factors in NADH recycling and mechanisms of 1,3-propanediol (1,3-PDO) production in Lactobacillus panis PM1. METHODS AND RESULTS We conducted metabolite analyses, qRT-PCR of the glycerol reductive pathway [glycerol dehydratase (DhaB) and 1,3-PDO dehydrogenase (DhaT)] and DhaT activity assays at different pH, temperature and initial glycerol concentrations. The supplementation of 150 mmol l(-1) glycerol caused a shift in NADH flux from ethanol to 1,3-PDO production, whereas 300 mol l(-1) glycerol negatively affected the regeneration of NAD(+) via 1,3-PDO production. This retardation decreased transcription levels and specific activities of DhaT. The decreased DhaT activity eventually caused the shutdown of 1,3-PDO production. Temperature and pH did not significantly affect the specific activity of DhaT, whereas expression of genes for DhaB and DhaT was activated under acidic conditions. Moreover, fresh glucose addition after its depletion could not restart the glycerol reduction, but increased ethanol production. CONCLUSIONS Those environmental factors affect 1,3-PDO production in different ways through changing the expression level of enzymes and shifting the NAD(+) regeneration pathways. SIGNIFICANCE AND IMPACT OF THE STUDY Our findings elucidated a key element to optimize 1,3-PDO production by Lact. panis PM1, which potentially improves 1,3-PDO manufacturing efficiencies.
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Affiliation(s)
- T S Kang
- Department of Food and Bioproduct Sciences, College of Agriculture and Bioresources, University of Saskatchewan, Saskatoon, SK, Canada
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29
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Abstract
BACKGROUND AND OBJECTIVE CYP2C19 is clinically important in Korea because of the relatively high incidence of poor metabolizers in the population. To fully understand the genetic mechanism of the CYP2C19 defect in poor metabolizers, all variants need to be studied simultaneously. The aim of this study was to investigate the usefulness of CYP2C19 haplotypes as a marker of CYP2C19 enzyme activity in Koreans. METHODS We analysed the single nucleotide polymorphisms and haplotypes of the CYP2C19 gene in 150 healthy Koreans and found three major (frequency > 0.1) haplotypes (H1, H2 and H3). One oral dose of 40 mg omeprazole (Losec) was administered to 30 subjects grouped as H1/H1, H2/H2, H1/H2, H1/H3 and H2/H3. The pharmacokinetics of omeprazole and its metabolites, 5-hydroxyomeprazole and omeprazole sulphone, in those groups was analysed. RESULTS AND DISCUSSION The area under the plasma concentration-time curve (AUC(0-->infinity)) and elimination half-life (T(1/2)) of omeprazole were significantly greater in the H2/H2 and H2/H3 groups than in the H1/H1 group (P < 0.05), whereas the metabolic ratios of omeprazole to 5-hydroxyomeprazole were also markedly higher. CONCLUSION Although a specific SNP of CYP2C19 may be predictive of enzyme activity, haplotyping is more reliable for identifying poor metabolizers in populations with variant alleles other than CYP2C19*2 and *3 alleles.
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Affiliation(s)
- S K Jin
- Department of Pharmacological Research, National Institute of Toxicological Research, Korea Food and Drug Administration, Seoul, South Korea
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Lee Y, Kang TS, Woo SW, Roh J. The Potential of Korea National Health Insurance Data as a Data Source for Pharmacovigilance. Drug Saf 2007. [DOI: 10.2165/00002018-200730100-00032] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
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Lee J, Kwon HM, Hong BK, Kim HK, Kwon KW, Kim JY, Lee KJ, Kang TS, Kim DS, Shin YH, Leem JS, Kim HS. Total occlusion of left main coronary artery by dilated main pulmonary artery in a patient with severe pulmonary hypertension. Korean J Intern Med 2001; 16:265-9. [PMID: 11855158 PMCID: PMC4578064 DOI: 10.3904/kjim.2001.16.4.265] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Abstract
A 34-year-old woman was admitted to the hospital because of recently aggravated right heart failure without angina for 5 months. When she was 25 years old, patch repair with Polytetrafluoroethylene (PTFE) was performed for the secondum type of atrial septal defect (ASD) with moderate pulmonary hypertension. The chest PA, echocardiography and cardiac catheterization at current admission revealed Eisenmenger syndrome without intracardiac shunt. Chest CT scan with contrast revealed markedly dilated pulmonary trunk, both pulmonary arteries and concave disfigurement of the left side of the ascending aorta suggesting extrinsic compression, as well as total occlusion of the ostium of the left main coronary artery that was retrogradly filled with collateral circulation from the right coronary artery. The coronary angiography showed normal right coronary artery and the collaterals that come out from the conus branch to the mid-left anterior descending artery (LAD) and that from distal right coronary artery to the left circumflex artery (LCX) and to the distal LAD, respectively. On aortography, the left main coronary artery was not visualized with no stump, suggestive of total occlusion of the ostium of the left main coronary artery. From our experience, it is possible to say that the occlusion of the ostium of the left main coronary can be induced by the dilated pulmonary artery trunk due to ASD with pulmonary hypertension and that, if the ASD closure was too late, the narrowing or obstruction of the left coronary artery could not be resolved even after operation owing to irreversible pulmonary hypertension.
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Affiliation(s)
- J Lee
- Cardiology Division, Department of Internal Medicine, Yonsei University College of Medicine, Seoul, Korea, 146-92, Dogok-Dong, Kangnam-Gu, Seoul 135-270, Korea
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Kwon HM, Hong BK, Kang TS, Kwon K, Kim HK, Jang Y, Choi D, Park HY, Kang SM, Cho SY, Kim HS. Expression of osteopontin in calcified coronary atherosclerotic plaques. J Korean Med Sci 2000; 15:485-93. [PMID: 11068982 PMCID: PMC3054686 DOI: 10.3346/jkms.2000.15.5.485] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Advanced atherosclerosis is often associated with dystrophic calcification and remodeling of extracellular matrix of vascular wall. Recently many studies have documented a general relationship between calcification and severity of coronary disease, and discussed the feasibility of electron beam computed tomography for detecting and quantifying the coronary artery calcification in the patients. The present study investigated the expression and the localization of osteopontin, one of noncollagenous bone matrix protein, within the calcified coronary arteries. Autopsy-derived coronary artery specimens were scanned and reconstructed to visualize the pattern of coronary calcification using a novel microscopic computed tomography technique. The localization of the osteopontin were evaluated by immunohistochemial stain with LF7. The present study showed that the pattern of coronary calcification is variable and the expression of osteopontin is localized mainly to calcified lesion. The smooth muscle cells in addition to macrophage expressed osteopontin protein in human coronary atherosclerotic plaques. Soluble osteopontin released near to the sites of vascular calcification may represent an adaptive mechanism aimed at regulating the process of vascular calcification.
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Affiliation(s)
- H M Kwon
- Yonsei Cardiovascular Center and Research Institute, Department of Internal Medicine, Yonsei University College of Medicine, Seoul, Korea.
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Song YG, Kwon HM, Kim JM, Hong BK, Kim DS, Huh AJ, Chang KH, Kim HY, Kang TS, Lee BK, Choi DH, Jang YS, Kim HS. Serologic and histopathologic study of Chlamydia pneumoniae infection in atherosclerosis: a possible pathogenetic mechanism of atherosclerosis induced by Chlamydia pneumoniae. Yonsei Med J 2000; 41:319-27. [PMID: 10957885 DOI: 10.3349/ymj.2000.41.3.319] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Abstract
Chronic infection and inflammation have recently been implicated as important etiologic agents for atherosclerosis in general and, in particular, ischemic heart disease. Several agents have been suggested as possible candidates for the chronic inflammation including cytomegalovirus, Helicobacter pylori and Chlamydia pneumoniae. We hypothesized that a vascular infection with C. pneumoniae may induce a chronic inflammatory reaction in the host vascular tissue and activated inflammatory cells may express inflammatory mediators such as cyclooxygenase-2 (COX-2) and matrix metalloproteinases (MMPs). At first, we evaluated the relationship between C. pneumoniae infection and atherosclerosis indirectly by serologic study, and then, to confirm our hypothesis, we performed an immunohistochemical study of atherosclerotic plaques. The seropositive rate of anti-Chlamydia pneumoniae IgG was higher in the disease group (Group I, 59.8%, n = 254) than in the negative control group (Group III, 47.4%, n = 97) (p = 0.041), but the anti-Chlamydia pneumoniae IgA was not different in seropositivity between the two groups (Group I, 64.6%; Group III, 57.7%). The simultaneous seropositive rates of both IgG and IgA were 56.7% in Group I and 43.3% in Group III (p = 0.033). In subgroups without the conventional risk factors of atherosclerosis, these findings were more prominent. Furthermore, we performed immunohistochemical staining on the atherosclerotic aortic tissues obtained from patients that were seropositive to C. pneumoniae (n = 5), by using antibodies to C. pneumoniae, COX-2, and MMP-9. The immunoreactivity for COX-2 and MMP-9 increased in the atherosclerotic plaques itself, predominantly in the surrounding area of immunoreactive C. pneumoniae. These findings support our hypothesis and C. pneumoniae may participate in a pathogenetic mechanism for atherogenesis or progression of atherosclerosis. The present study may open a promising perspective concerning future therapeutic trials of chronic inflammation related atherogenesis under pathophysiological conditions.
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Affiliation(s)
- Y G Song
- Department of Internal Medicine, Yonsei University College of Medicine, Seoul, Korea
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Abstract
OBJECTIVE/HYPOTHESIS To determine if angiogenic growth factors including vascular endothelial growth factor (VEGF) and platelet-derived endothelial cell growth factor (PD-ECGF) are expressed in human paragangliomas. STUDY DESIGN A histopathologic and molecular examination of paraganglioma specimens obtained from surgical cases or retrieved from the Pathology Department of the Massachusetts Eye and Ear Infirmary. METHODS Fresh tumor or archival, paraffin-embedded paraganglioma specimens were analyzed by immunohistochemistry, Western blotting, and ELISA. RESULTS Positive immunohistochemical staining for VEGF was observed in five of nine surgical specimens and in six of eight archival specimens (11/17, or 65%). PD-ECGF immunoreactivity was detected in four of five surgical specimens and six of eight archival specimens (10/13, or 77%). The presence of PD-ECGF was confirmed by Western blot assay and ELISA confirmed the presence of VEGF in tumor extract. CONCLUSIONS Both VEGF and PD-ECGF are expressed in paragangliomas and may contribute to the extreme vascularity of these tumors. Key Words. Vascular endothelial growth factor, platelet-derived, endothelial cell growth factor, hypoxia, tumor vasculature.
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Affiliation(s)
- R W Jyung
- Department of Otorhinolaryngology, Temple University School of Medicine, Philadelphia, Pennsylvania 19140, USA.
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Hong BK, Kwon HM, Byun KH, Kim D, Choi EY, Kang TS, Kang SM, Chun KJ, Jang Y, Kim HS, Kim M. Apoptosis in dilated cardiomyopathy. Korean J Intern Med 2000; 15:56-64. [PMID: 10714093 PMCID: PMC4531747 DOI: 10.3904/kjim.2000.15.1.56] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Abstract
OBJECTIVE Cardiomyopathy, a popular diagnosis that always obscures more than it reveals, nevertheless has several characteristic histological features. These prominently include widespread focal myocardial fibrosis and associated hypertrophy of surviving cardiac myocyte. In fact, focal noninflammatory degeneration (not necrosis) has been demonstrated as a feature of many forms of cardiac hypertrophy. We hypothesized that this loss of myocardial cells in dilated cardiomyopathy (DCMP) may result from cell death by apoptosis. METHODS Endomyocardial biopsy specimens from the right ventricles of six patients who suffered from DCMP were studied, and myocardial specimens from two persons who died in motor vehicle accidents were used as negative controls. For identification of apoptosis, immunohistochemistry with terminal deoxynucleotidyl transferase (TdT)-mediated dUTP-biotin nick end-labeling was performed. In addition, apoptosis was confirmed morphologically by confocal laser scanning microscopy with propidium iodide. RESULTS Apoptosis, that was represented by an apoptotic index ranging from 19.8 to 25.4%, could be extensively seen in myocytes and also rarely in non-myocytes of interstitium and vascular endothelium. Morphologically, there were a lot of nuclei with clumps of condensed chromatin, suggestive of apoptosis. CONCLUSION The present study demonstrated that myocyte loss in DCMP might be mainly due to the apoptosis of myocytes and interstitial cells, rather than inflammation or cell necrosis.
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Affiliation(s)
- B K Hong
- Cardiology Division, Yonsei Cardiovascular Center, Yonsei University College of Medicine, Seoul, Korea
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Oleshko VP, Gijbels RH, Van Daele AJ, Jacob WA, Xu YE, Wang SE, Park IY, Kang TS. Combined characterization of composite tabular silver halide microcrystals by cryo-EFTEM/EELS and cryo-STEM/EDX techniques. Microsc Res Tech 1998; 42:108-22. [PMID: 9728882 DOI: 10.1002/(sici)1097-0029(19980715)42:2<108::aid-jemt5>3.0.co;2-p] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
The combination of cryo-energy filtering transmission electron microscopy (EFTEM)/electron spectroscopic diffraction (ESD)/electron energy-loss spectroscopy (EELS) and cryo-energy-dispersive X-ray (EDX) analysis in the scanning transmission (STEM) and scanning (SEM) modes was applied for the characterization of composite tabular Ag(Br,I) microcrystals. A low-loss fine structure in EEL spectra between 4 and 26 eV was attributed to excitons and plasmons possibly superimposed with interband transitions and many-electron effects. The contrast tuning under the energy-filtering in the low-loss region was used to image the crystal morphology, defect structure (random dislocations and ¿111¿ stacking faults) and bend and edge contours as well as electron excitations in the microcrystals. Sharp extra reflections at commensurate positions in between the main Bragg reflections and diffuse honeycomb contours in ESD patterns of the microcrystals taken near the [111] zone were assigned to the number of defects in the shell region parallel to the grain edges and polyhedral clusters of interstitial silver cations, respectively. The imaginary part of the energy-loss function, Im (-1/epsilon), and the real and imaginary parts, epsilon1 and epsilon2, of the dielectric permittivity were determined by means of a Kramers-Kronig analysis. An assignment of exciton peaks based on calculations of electronic band structure of silver bromide is proposed. Inner-shell excitation bands of silver halide were detected in line with EDX-analyses. The energy-loss near-edge structure (ELNES) of the AgM4,5-edge governed by spin-orbital splitting between the 3d3/2- and 3d5/2-states has been evaluated. Combined silver and halide distributions were obtained by a three-window method (EFTEM) and by EDX/STEM including area mapping and line profiling of iodide.
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Affiliation(s)
- V P Oleshko
- Micro- and Trace Analysis Center, Department of Chemistry, University of Antwerp (UIA), Wilrijk-Antwerpen, Belgium.
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Lee KC, Kang TS, Woo BH, Lee JT, Lee HS, DeLuca PP. Reversed-phase high-performance liquid chromatography of radioiodinated salmon calcitonins. J Chromatogr B Biomed Sci Appl 1997; 694:31-7. [PMID: 9234845 DOI: 10.1016/s0378-4347(97)00154-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Reversed-phase HPLC conditions for simultaneous separation of salmon calcitonin, mono- and di-radioiodinated salmon calcitonins and their tryptic digested fragments have been developed. Salmon calcitonin was radioiodinated with Na125I by the iodo-beads method. After solid-phase extraction from the reaction mixtures using C18 Bond Elut cartridges, mono- and di-radioiodinated salmon calcitonins were separated from each other, as well as from unlabeled salmon calcitonin, on a Bondclone 10 C18 column (300x7.8 mm I.D.) by isocratic elution with 0.1% trifluoroacetic acid in 34% aqueous acetonitrile. The characteristics of either iodinated peptides or unlabeled salmon calcitonin were evaluated on the basis of UV absorbance (215 and 280 nm), fluorescence (lambda(ex)=282 nm, lambda(em)=310 nm) and measurement of specific radioactivity by means of a flow-through radio-isotope detector. HPLC separation of a tryptic digest of iodinated salmon calcitonin fraction on a W-porex 5 C18 300 A column (250x4.6 mm I.D.) and subsequent amino acid analysis, led to the conclusion that radioiodination took place at the Tyr residue and not at the His moiety.
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Affiliation(s)
- K C Lee
- College of Pharmacy, SungKyunKwan University, Jangan-ku, Suwon City, South Korea
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Bazargan M, Kang TS, Bazargan S. A multivariate comparison of elderly African Americans and Caucasians voting behavior: how do social, health, psychological, and political variables effect their voting? Int J Aging Hum Dev 1991; 32:181-98. [PMID: 2060982 DOI: 10.2190/49tt-9afr-ux2g-pgfu] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
No study until now has examined the impact of the physical and psychological condition on voter turnout among elderly African Americans and Caucasians. Utilizing data from a national survey (Aging in the Eighties) and using multiple logistic regression, the present study examines the impact of health rating and life satisfaction as well as other socio-psychological characteristics on voting turnout among elderly Caucasian and African Americans. The results provide some empirical evidence that the pattern of election participation can be significantly influenced by the self-assessment of health and life satisfaction. For elderly Caucasians self-assessment of health is significantly related to voting behavior, whereas among elderly African Americans life satisfaction shows significant impact on turnout. Elderly African Americans who identified their personal political philosophy as "liberal" were more likely to vote, while among elderly Caucasians, those who identified their personal political philosophy as "conservative" were more likely to vote. In addition, SES, age, and organizational activity proved to have significantly independent impact on elderly Caucasian turnout, whereas among elderly African Americans, education was detected as a significant predictor.
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