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Chuang CH, Kang PH, Lai YY, Hou CH, Tseng WC, Huang YJ, Fang MH, Shyue JJ, Kaun CC, Cheng YJ. Highly Active NiO-Ni(OH) 2 -Cr 2 O 3 /Ni Hydrogen Evolution Electrocatalyst through Synergistic Reaction Kinetics. ChemSusChem 2023; 16:e202300820. [PMID: 37421638 DOI: 10.1002/cssc.202300820] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/02/2023] [Revised: 07/06/2023] [Accepted: 07/07/2023] [Indexed: 07/10/2023]
Abstract
High activity catalysts for hydrogen evolution reaction (HER) play a key role in converting renewable electricity to storable hydrogen fuel. Great effort has been devoted to the search for noble metal free catalysts to make electrolysis viable for practical applications. Here, a non-precious metal oxide/metal catalyst with high intrinsic activity comparable to Pt/C was reported. The electrocatalyst consisting of NiO, Ni(OH)2 , Cr2 O3 , and Ni metal exhibits a low overpotential of 27, 103, and 153 mV at current densities of 10, 100, and 200 mA cm-2 , respectively, in a 1.0 m NaOH electrolyte. The activity is much higher than that of NiOx /Ni or Cr2 O3 alone, showing the synergistic effect of NiOx /Ni and Cr2 O3 on catalyzing HER. Density functional theory calculations shows that NiO and Cr2 O3 on Ni surface lower the disassociation energy barrier for breaking H-OH bond, while Ni(OH)2 and Cr2 O3 create preferred sites on Ni surface with near-zero H* adsorption free energy to promote H* to gaseous H2 evolution. These synergistic effects of multiple-oxides/metal composition enhance the disassociation of H-OH and the evolution of H* to gaseous H2 , thus achieving high activity and demonstrating a promising composition design for noble metal free catalyst.
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Affiliation(s)
- Chi-Huang Chuang
- Research Center for Applied Sciences, Academia Sinica, 128 Sec. 2, Academia Rd, Nankang, Taipei, 115, Taiwan
| | - Pei-Hao Kang
- Research Center for Applied Sciences, Academia Sinica, 128 Sec. 2, Academia Rd, Nankang, Taipei, 115, Taiwan
| | - Yung-Yu Lai
- Research Center for Applied Sciences, Academia Sinica, 128 Sec. 2, Academia Rd, Nankang, Taipei, 115, Taiwan
| | - Cheng-Hung Hou
- Research Center for Applied Sciences, Academia Sinica, 128 Sec. 2, Academia Rd, Nankang, Taipei, 115, Taiwan
| | - Wei-Che Tseng
- Department of Materials Science and Engineering, National Cheng Kung University, No.1, University Road, Tainan, 701, Taiwan
| | - Yan-Jia Huang
- Department of Materials Science and Engineering, National Cheng Kung University, No.1, University Road, Tainan, 701, Taiwan
| | - Mu-Huai Fang
- Research Center for Applied Sciences, Academia Sinica, 128 Sec. 2, Academia Rd, Nankang, Taipei, 115, Taiwan
| | - Jing-Jong Shyue
- Research Center for Applied Sciences, Academia Sinica, 128 Sec. 2, Academia Rd, Nankang, Taipei, 115, Taiwan
| | - Chao-Cheng Kaun
- Research Center for Applied Sciences, Academia Sinica, 128 Sec. 2, Academia Rd, Nankang, Taipei, 115, Taiwan
| | - Yuh-Jen Cheng
- Research Center for Applied Sciences, Academia Sinica, 128 Sec. 2, Academia Rd, Nankang, Taipei, 115, Taiwan
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2
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Wang TH, Tseng WC, Leu YL, Chen CY, Lee WC, Chi YC, Cheng SF, Lai CY, Kuo CH, Yang SL, Yang SH, Shen JJ, Feng CH, Wu CC, Hwang TL, Wang CJ, Wang SH, Chen CC. The flavonoid corylin exhibits lifespan extension properties in mouse. Nat Commun 2022; 13:1238. [PMID: 35264584 PMCID: PMC8907184 DOI: 10.1038/s41467-022-28908-2] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [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: 12/08/2020] [Accepted: 02/16/2022] [Indexed: 01/23/2023] Open
Abstract
In the long history of traditional Chinese medicine, single herbs and complex formulas have been suggested to increase lifespan. However, the identification of single molecules responsible for lifespan extension has been challenging. Here, we collected a list of traditional Chinese medicines with potential longevity properties from pharmacopeias. By utilizing the mother enrichment program, we systematically screened these traditional Chinese medicines and identified a single herb, Psoralea corylifolia, that increases lifespan in Saccharomyces cerevisiae. Next, twenty-two pure compounds were isolated from Psoralea corylifolia. One of the compounds, corylin, was found to extend the replicative lifespan in yeast by targeting the Gtr1 protein. In human umbilical vein endothelial cells, RNA sequencing data showed that corylin ameliorates cellular senescence. We also examined an in vivo mammalian model, and found that corylin extends lifespan in mice fed a high-fat diet. Taken together, these findings suggest that corylin may promote longevity.
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Affiliation(s)
- Tong-Hong Wang
- Tissue Bank, Chang Gung Memorial Hospital, Taoyuan, Taiwan.,Graduate Institute of Health Industry Technology, Research Center for Food and Cosmetic Safety, Research Center for Chinese Herbal Medicine, College of Human Ecology, Chang Gung University of Science and Technology, Taoyuan, Taiwan
| | - Wei-Che Tseng
- Graduate Institute of Natural Products, Chang Gung University, Taoyuan, Taiwan
| | - Yann-Lii Leu
- Tissue Bank, Chang Gung Memorial Hospital, Taoyuan, Taiwan.,Graduate Institute of Natural Products, Chang Gung University, Taoyuan, Taiwan
| | - Chi-Yuan Chen
- Tissue Bank, Chang Gung Memorial Hospital, Taoyuan, Taiwan.,Graduate Institute of Health Industry Technology, Research Center for Food and Cosmetic Safety, Research Center for Chinese Herbal Medicine, College of Human Ecology, Chang Gung University of Science and Technology, Taoyuan, Taiwan
| | - Wen-Chih Lee
- Office of Research and Development, Tzu Chi University, Hualien, Taiwan
| | - Ying-Chih Chi
- Cryo-EM Center, Vagelos College of Physicians and Surgeons, Columbia University Irving Medical Center, New York, USA
| | - Shu-Fang Cheng
- Graduate Institute of Natural Products, Chang Gung University, Taoyuan, Taiwan
| | - Chun-Yu Lai
- Graduate Institute of Natural Products, Chang Gung University, Taoyuan, Taiwan
| | - Chen-Hsin Kuo
- Graduate Institute of Natural Products, Chang Gung University, Taoyuan, Taiwan
| | - Shu-Ling Yang
- School of Traditional Chinese Medicine, Chang Gung University, Taoyuan, Taiwan
| | - Sien-Hung Yang
- School of Traditional Chinese Medicine, Chang Gung University, Taoyuan, Taiwan.,Division of Chinese Internal Medicine, Center for Traditional Chinese Medicine, Chang Gung Memorial Hospital, Taoyuan, Taiwan
| | - Jiann-Jong Shen
- School of Traditional Chinese Medicine, Chang Gung University, Taoyuan, Taiwan
| | - Chun-Hao Feng
- Graduate Institute of Natural Products, Chang Gung University, Taoyuan, Taiwan
| | - Chih-Ching Wu
- Department of Medical Biotechnology and Laboratory Science, Chang Gung University, Taoyuan, Taiwan.,Department of Otolaryngology-Head & Neck Surgery, Chang Gung Memorial Hospital, Taoyuan, Taiwan.,Molecular Medicine Research Center, Chang Gung University, Taoyuan, Taiwan.,Research Center for Emerging Viral Infections, College of Medicine, Chang Gung University, Taoyuan, Taiwan
| | - Tsong-Long Hwang
- Graduate Institute of Health Industry Technology, Research Center for Food and Cosmetic Safety, Research Center for Chinese Herbal Medicine, College of Human Ecology, Chang Gung University of Science and Technology, Taoyuan, Taiwan.,Graduate Institute of Natural Products, Chang Gung University, Taoyuan, Taiwan.,Department of Anesthesiology, Chang Gung Memorial Hospital, Taoyuan, Taiwan
| | - Chia-Jen Wang
- Cell Therapy Core Laboratory, Chang Gung Memorial Hospital, Taoyuan, Taiwan
| | - Shu-Huei Wang
- Department of Anatomy and Cell Biology, College of Medicine, National Taiwan University, Taipei, Taiwan.
| | - Chin-Chuan Chen
- Tissue Bank, Chang Gung Memorial Hospital, Taoyuan, Taiwan. .,Graduate Institute of Natural Products, Chang Gung University, Taoyuan, Taiwan.
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3
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Tseng WC, Chen CY, Chern CY, Wang CA, Lee WC, Chi YC, Cheng SF, Kuo YT, Chiu YC, Tseng ST, Lin PY, Liou SJ, Li YC, Chen CC. Targeting HR Repair as a Synthetic Lethal Approach to Increase DNA Damage Sensitivity by a RAD52 Inhibitor in BRCA2-Deficient Cancer Cells. Int J Mol Sci 2021; 22:4422. [PMID: 33922657 PMCID: PMC8122931 DOI: 10.3390/ijms22094422] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2021] [Revised: 04/21/2021] [Accepted: 04/22/2021] [Indexed: 02/01/2023] Open
Abstract
BRCA mutation, one of the most common types of mutations in breast and ovarian cancer, has been suggested to be synthetically lethal with depletion of RAD52. Pharmacologically inhibiting RAD52 specifically eradicates BRCA-deficient cancer cells. In this study, we demonstrated that curcumin, a plant polyphenol, sensitizes BRCA2-deficient cells to CPT-11 by impairing RAD52 recombinase in MCF7 cells. More specifically, in MCF7-siBRCA2 cells, curcumin reduced homologous recombination, resulting in tumor growth suppression. Furthermore, a BRCA2-deficient cell line, Capan1, became resistant to CPT-11 when BRCA2 was reintroduced. In vivo, xenograft model studies showed that curcumin combined with CPT-11 reduced the growth of BRCA2-knockout MCF7 tumors but not MCF7 tumors. In conclusion, our data indicate that curcumin, which has RAD52 inhibitor activity, is a promising candidate for sensitizing BRCA2-deficient cells to DNA damage-based cancer therapies.
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Affiliation(s)
- Wei-Che Tseng
- Graduate Institute of Natural Products, Chang Gung University, Taoyuan 333, Taiwan; (W.-C.T.); (S.-F.C.); (Y.-T.K.); (Y.-C.C.); (S.-T.T.); (P.-Y.L.); (S.-J.L.)
| | - Chi-Yuan Chen
- Tissue Bank, Chang Gung Memorial Hospital, Taoyuan 333, Taiwan;
- Graduate Institute of Health Industry Technology and Research Center for Chinese Herbal Medicine, College of Human Ecology, Chang Gung University of Science and Technology, Taoyuan 333, Taiwan
| | - Ching-Yuh Chern
- Department of Applied Chemistry, National Chiayi University, Chiayi 600, Taiwan; (C.-Y.C.); (Y.-C.L.)
| | - Chu-An Wang
- Department of Physiology, College of Medicine, National Cheng Kung University, Tainan 701, Taiwan;
| | - Wen-Chih Lee
- Translational Research Program in Pediatric Orthopedics, The Children’s Hospital of Philadelphia, Philadelphia, PA 19104, USA;
| | - Ying-Chih Chi
- Cryo-EM Center, Vagelos College of Physicians and Surgeons, Columbia University Irving Medical Center, New York, NY 10032, USA;
| | - Shu-Fang Cheng
- Graduate Institute of Natural Products, Chang Gung University, Taoyuan 333, Taiwan; (W.-C.T.); (S.-F.C.); (Y.-T.K.); (Y.-C.C.); (S.-T.T.); (P.-Y.L.); (S.-J.L.)
| | - Yi-Tsen Kuo
- Graduate Institute of Natural Products, Chang Gung University, Taoyuan 333, Taiwan; (W.-C.T.); (S.-F.C.); (Y.-T.K.); (Y.-C.C.); (S.-T.T.); (P.-Y.L.); (S.-J.L.)
| | - Ya-Chen Chiu
- Graduate Institute of Natural Products, Chang Gung University, Taoyuan 333, Taiwan; (W.-C.T.); (S.-F.C.); (Y.-T.K.); (Y.-C.C.); (S.-T.T.); (P.-Y.L.); (S.-J.L.)
| | - Shih-Ting Tseng
- Graduate Institute of Natural Products, Chang Gung University, Taoyuan 333, Taiwan; (W.-C.T.); (S.-F.C.); (Y.-T.K.); (Y.-C.C.); (S.-T.T.); (P.-Y.L.); (S.-J.L.)
| | - Pei-Ya Lin
- Graduate Institute of Natural Products, Chang Gung University, Taoyuan 333, Taiwan; (W.-C.T.); (S.-F.C.); (Y.-T.K.); (Y.-C.C.); (S.-T.T.); (P.-Y.L.); (S.-J.L.)
| | - Shou-Jhen Liou
- Graduate Institute of Natural Products, Chang Gung University, Taoyuan 333, Taiwan; (W.-C.T.); (S.-F.C.); (Y.-T.K.); (Y.-C.C.); (S.-T.T.); (P.-Y.L.); (S.-J.L.)
| | - Yi-Chen Li
- Department of Applied Chemistry, National Chiayi University, Chiayi 600, Taiwan; (C.-Y.C.); (Y.-C.L.)
| | - Chin-Chuan Chen
- Graduate Institute of Natural Products, Chang Gung University, Taoyuan 333, Taiwan; (W.-C.T.); (S.-F.C.); (Y.-T.K.); (Y.-C.C.); (S.-T.T.); (P.-Y.L.); (S.-J.L.)
- Tissue Bank, Chang Gung Memorial Hospital, Taoyuan 333, Taiwan;
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4
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Wu ZF, Hsu YC, Tseng WC. Hiccups : an uncommon presentation of pyogenic liver abscess. Acta Gastroenterol Belg 2020; 83:92-93. [PMID: 32233280] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Affiliation(s)
- Z F Wu
- Department of Anesthesiology, Chi Mei Medical Center, Tainan, Taiwan, R.O.C
| | - Y C Hsu
- Department of Anesthesiology, Tri-Service General Hospital and National Defense Medical Center, Taipei, Taiwan, R.O.C
| | - W C Tseng
- Department of Anesthesiology, Tri-Service General Hospital and National Defense Medical Center, Taipei, Taiwan, R.O.C
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5
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Kuo CH, Leu YL, Wang TH, Tseng WC, Feng CH, Wang SH, Chen CC. A novel DNA repair inhibitor, diallyl disulfide (DADS), impairs DNA resection during DNA double-strand break repair by reducing Sae2 and Exo1 levels. DNA Repair (Amst) 2019; 82:102690. [PMID: 31479843 DOI: 10.1016/j.dnarep.2019.102690] [Citation(s) in RCA: 9] [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] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2019] [Revised: 07/25/2019] [Accepted: 08/13/2019] [Indexed: 12/26/2022]
Abstract
Combining natural products with chemotherapy and/or radiotherapy may increase the efficacy of cancer treatment. It has been hypothesized that natural products may inhibit DNA repair and sensitize cancer cells to DNA damage-based cancer therapy. However, the molecular mechanisms underlying these activities remain unclear. In this study, we found that diallyl disulfide (DADS), an organosulfur compound, increased the sensitivity of yeast cells to DNA damage and has potential for development as an adjuvant drug for DNA damage-based cancer therapy. We induced HO endonuclease to generate a specific DNA double-strand break (DSB) by adding galactose to yeast and used this system to study how DADS affects DNA repair. In this study, we found that DADS inhibited DNA repair in single-strand annealing (SSA) system and sensitized SSA cells to a single DSB. DADS impaired DNA repair by inhibiting the protein levels of the DNA resection-related proteins Sae2 and Exo1. We also found that the recruitment of MRX and the Mec1-Ddc2 complex to a DSB was prevented by DADS. This result suggests that DADS counteracts G2/M DNA damage checkpoint activation in a Mec1 (ATR)- and Tel1 (ATM)-dependent manner. Only by elucidating the molecular mechanisms by which DADS influences DNA repair will we be able to discover new adjuvant drugs to improve chemotherapy and/or radiotherapy.
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Affiliation(s)
- Chen-Hsin Kuo
- Graduate Institute of Biomedical Sciences, College of Medicine, Chang Gung University, Taoyuan, Taiwan
| | - Yann-Lii Leu
- Graduate Institute of Natural Products, College of Medicine, Chang Gung University, Taoyuan, Taiwan; Center for Traditional Chinese Medicine, Chang Gung Memorial Hospital, Taoyuan, Taiwan
| | - Tong-Hong Wang
- Tissue Bank, Chang Gung Memorial Hospital, Taoyuan, Taiwan; Graduate Institute of Health Industry Technology, Research Center for Industry of Human Ecology, College of Human Ecology, Chang Gung University of Science and Technology, Taoyuan, Taiwan; Liver Research Center, Chang Gung Memorial Hospital, Linko, Taiwan
| | - Wei-Che Tseng
- Graduate Institute of Natural Products, College of Medicine, Chang Gung University, Taoyuan, Taiwan
| | - Chun-Hao Feng
- Graduate Institute of Natural Products, College of Medicine, Chang Gung University, Taoyuan, Taiwan
| | - Shu-Huei Wang
- Department of Anatomy and Cell Biology, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Chin-Chuan Chen
- Graduate Institute of Biomedical Sciences, College of Medicine, Chang Gung University, Taoyuan, Taiwan; Graduate Institute of Natural Products, College of Medicine, Chang Gung University, Taoyuan, Taiwan; Tissue Bank, Chang Gung Memorial Hospital, Taoyuan, Taiwan.
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6
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Tseng WC, Hsieh RL. Effects of short-term active video game play on community adults: under International Classification of Functioning, Disability and Health consideration. Chin Med J (Engl) 2013; 126:2313-2319. [PMID: 23786945] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/02/2023] Open
Abstract
BACKGROUND The effects of active video game play on healthy individuals remain uncertain. A person's functional health status constitutes a dynamic interaction between components identified in the International Classification of Functioning, Disability, and Health (ICF). The aim of this study was to investigate the short-term effects of active video game play on community adults using the ICF. METHODS Sixty community adults with an average age of 59.3 years and without physical disabilities were recruited. Over 2 weeks, each adult participated in six sessions of active video game play lasting 20 minutes each. Participants were assessed before and after the intervention. Variables were collected using sources related to the ICF components, including the Hospital Anxiety and Depression Scale, Multidimensional Fatigue Inventory, Biodex Stability System, chair- rising time, Frenchay Activity Index, Rivermead Mobility Index, Chronic Pain Grade Questionnaire, Work Ability Index, and World Health Organization Quality of Life-Brief Version. RESULTS Compared to baseline data, significantly reduced risk of a fall measured by Biodex Stability System and improvements in disability scores measured by the Chronic Pain Grade Questionnaire were noted. There was no significant change in the other variables measured. CONCLUSION Short-term, active video game play reduces fall risks and ameliorates disabilities in community adults.
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Affiliation(s)
- Wei-Che Tseng
- Department of Physical Medicine and Rehabilitation, Shin Kong Wu Ho-Su Memorial Hospital, Taipei 11101, Taiwan, China
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7
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Hsieh RL, Hsueh YM, Huang HY, Lin MI, Tseng WC, Lee WC. Quality of life and impact of children with unclassified developmental delays. J Paediatr Child Health 2013; 49:E116-21. [PMID: 23316900 DOI: 10.1111/jpc.12081] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 06/09/2012] [Indexed: 11/29/2022]
Abstract
AIMS The study aims to evaluate the quality of life (QOL) and health of children with unclassified developmental delays and the impacts this had on the family. METHODS In total, 60 parents of pre-school children with unclassified developmental delays and 56 parents of age and gender-matched children with typical development were recruited. We administered the Pediatric Quality of Life Inventory (PedsQL)-Generic Core Scale and Pediatric Outcomes Data Collection Instrument to parents to evaluate the QOL and health status of their children. Parents were evaluated by World Health Organization-Quality of Life-Brief Version, PedsQL-Family Impact Module, Hospital Anxiety and Depression Scale, and PedsQL-Health satisfaction to assess the impacts of this situation on the family. Variables related to QOL and functions of children with unclassified developmental delays were analysed by stepwise regression analysis. RESULTS Comparing children with typical development, children with unclassified developmental delays had a significantly lower QOL (including both psychosocial and physical components) and health status. Their parents had a significantly lower QOL, family function and health satisfaction, and higher psychological distress than parents of children with typical development. Gross-motor delay impacts on QOL of these children (regression coefficient: -9.59, P < 0.05), global functioning is related to cognition delay (regression coefficient: -20.22, P < 0.01) and physical health of their parents (regression coefficient: 0.87, P < 0.01). CONCLUSIONS Children with unclassified developmental delays had lower QOL and health status, and their condition had greater impacts on the family than children with typical development. Gross motor and cognition development related to the QOL and global functioning in these children.
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Affiliation(s)
- Ru-Lan Hsieh
- Department of Physical Medicine and Rehabilitation, Shin Kong Wu Ho-Su Memorial Hospital, Taipei, Taiwan.
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8
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Zaremba AA, MacFarlane DL, Tseng WC, Stark AJ, Briggs RW, Gopinath KS, Cheshkov S, White KD. Optical head tracking for functional magnetic resonance imaging using structured light. J Opt Soc Am A Opt Image Sci Vis 2008; 25:1551-1557. [PMID: 18594610 DOI: 10.1364/josaa.25.001551] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
An accurate motion-tracking technique is needed to compensate for subject motion during functional magnetic resonance imaging (fMRI) procedures. Here, a novel approach to motion metrology is discussed. A structured light pattern specifically coded for digital signal processing is positioned onto a fiduciary of the patient. As the patient undergoes spatial transformations in 6 DoF (degrees of freedom), a high-resolution CCD camera captures successive images for analysis on a computing platform. A high-speed image processing algorithm is used to calculate spatial transformations in a time frame commensurate with patient movements (10-100 ms) and with a precision of at least 0.5 microm for translations and 0.1 deg for rotations.
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Affiliation(s)
- Andrei A Zaremba
- Department of Electrical Engineering, UNiversity of Texas at Dallas, Richardson, Texas 75080, USA
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9
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Sun YC, Lee YS, Shiah TL, Lee PL, Tseng WC, Yang MH. Comparative study on conventional and low-flow nebulizers for arsenic speciation by means of microbore liquid chromatography with inductively coupled plasma mass spectrometry. J Chromatogr A 2003; 1005:207-13. [PMID: 12924795 DOI: 10.1016/s0021-9673(03)00843-4] [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: 11/19/2022]
Abstract
The performance of conventional and low-flow nebulizer systems with liquid chromatography in differentiating four arsenic species in urine was evaluated. Two low-flow (DIN and MCN) chamber assemblies and a conventional (CFN) nebulizer-spray chamber assembly were compared in the hyphenation of anion-exchange microbore liquid chromatography with inductively coupled plasma mass spectrometry. Under optimal analytical conditions, the detection limits of the four arsenic species were 0.2-0.6 ng ml(-1) for all the nebulizer systems tested. The chromatographic resolution was best in the case of DIN due to its minimal off-column dead volume and superior transport efficiency. Four arsenic species were determined in the certified reference materials NIST SRM 2670E and 2670N.
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Affiliation(s)
- Y C Sun
- Nuclear Science and Technology Department Center, National Tsing-Hua University, 30043 Hsinchu, Taiwan.
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10
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Huang DW, Tseng WC. Mean-field theory for car accidents. Phys Rev E Stat Nonlin Soft Matter Phys 2001; 64:057106. [PMID: 11736147 DOI: 10.1103/physreve.64.057106] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/04/2001] [Revised: 07/06/2001] [Indexed: 05/23/2023]
Abstract
We study analytically the occurrence of car accidents in the Nagel-Schreckenberg traffic model. We obtain exact results for the occurrence of car accidents P(ac) as a function of the car density rho and the degree of stochastic braking p(1) in the case of speed limit v(max)=1. Various quantities are calculated analytically. The nontrivial limit p(1)-->0 is discussed.
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Affiliation(s)
- D W Huang
- Department of Physics, Chung Yuan Christian University, Chung-li, Taiwan
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11
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Huang YL, Tseng WC, Lin TH. In vitro effects of metal ions (Fe2+, Mn2+, Pb2+) on sperm motility and lipid peroxidation in human semen. J Toxicol Environ Health A 2001; 62:259-267. [PMID: 11245395 DOI: 10.1080/009841001459414] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
The effects of divalent manganese ion (Mn2+), ferrous iron (Fe2+), and lead ion (Pb2+) on human sperm motility and lipid peroxidation were examined. Human semen from healthy male volunteers was incubated with 0, 5, 50, or 500 ppm divalent metal ions, and the sperm motility was determined at 0, 2, 4, 6, or 8 h by microscopy. Malondialdehyde (MDA) levels in seminal plasma was measured by high-performance liquid chromatography after 8 h of exposure. The results showed that 500 ppm Mn2+ or Pb2+ significantly inhibited sperm motility without an accompanying change in seminal MDA levels. Incubation with Fe2+ significantly inhibited sperm motility at 5 ppm, associated with a marked rise in MDA levels. Our results suggested that Fe2+ may induce lipid peroxidation to inhibit sperm motility. In the case of Mn2+ and Pb2+ there is an absence of seminal lipid peroxidation and the observed inhibition of sperm motility at high concentrations is not biologically or environmentally relevant.
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Affiliation(s)
- Y L Huang
- School of Technology for Medical Sciences, Kaohsiung Medical University, Taiwan, Republic of China.
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12
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Huang YL, Tseng WC, Cheng SY, Lin TH. Trace elements and lipid peroxidation in human seminal plasma. Biol Trace Elem Res 2000; 76:207-15. [PMID: 11049219 DOI: 10.1385/bter:76:3:207] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.3] [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] [Received: 07/26/1999] [Revised: 08/18/1999] [Accepted: 11/20/1999] [Indexed: 11/11/2022]
Abstract
In the present study, the concentrations of copper, iron, zinc, and malondialdehyde in human seminal plasma were measured and correlated with the sperm count and motility in human semen. Copper, iron, and zinc were analyzed by atomic absorption spectrometry, whereas malondialdehyde was measured by high-performance liquid chromatography. The malondialdehyde concentrations in asthenospermia and oligoasthenospermia were significantly higher than in normospermia. Copper and iron levels were higher in asthenospermia, whereas the zinc concentrations in both oligospermia and asthenospermia were lower than in normal controls. A negative correlation (r = -0.28, p < 0.05) between the malondialdehyde concentration and sperm motility was observed in the abnormal groups. There was no association among copper, iron, zinc, and malondialdehyde in seminal plasma. We concluded that changes in trace elements may be related to sperm quality and that lipid peroxidation, although it is not promoted in the seminal plasma by copper or iron or ameliorated by zinc, may be involved in the loss of sperm motility.
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Affiliation(s)
- Y L Huang
- School of Technology for Medical Sciences, Kaohsiung Medical College, Taiwan, Republic of China
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Abstract
Cationic liposomes have provided many advantages over viral vector formulations; however, the problem of inefficient gene expression remains. This is due in part to the nuclear membrane, which limits DNA entry into the nucleus. Cytoplasmic expression systems using T7 RNA polymerase have been developed to express genes in the cytoplasm and avoid the need for nuclear import of DNA. Although these systems show improved transgene expression, little is known about how they function in transfected cells. Direct comparisons between a cytoplasmic and nuclear expression system were carried out with a 293 cell line stably expressing T7 RNA polymerase. A formulation for optimal reporter gene expression was developed and used in conjunction with a variety of subcellular trafficking inhibitors to study the process of DNA endocytosis. Transfected cells were also studied at different stages of the cell cycle to determine the dependence of each system on mitosis. These results showed that cytoplasmic and nuclear expression systems utilize similar endocytosis pathways to the point of endosomal release. Once DNA is released into the cytoplasm, the cytoplasmic expression system shows immediate expression that is proportional to the amount of DNA released. In contrast, DNA targeted for nuclear expression requires additional time for nuclear entry. The level of nuclear expression is also restricted by the limited amount of DNA that is imported into the nucleus. Finally, mitosis is required for effective nuclear expression but not for cytoplasmic expression. Therefore, the cytoplasmic expression system has considerable advantages over traditional nuclear expression systems and may be an effective method for transfecting nondividing cells. Efficient expression of genes delivered by nonviral vectors is hindered owing to poor nuclear transport of plasmid DNA. A potential solution to this problem would be to use a cytoplasmic expression system. Previous studies have shown that this method produces enhanced gene expression when compared with traditional nuclear expression systems; however, the actual mechanisms by which the cytoplasmic expression system works remains unknown. This article focuses on a direct comparison between cytoplasmic and nuclear expression in terms of optimal DNA delivery formulations, intracellular trafficking of DNA, and cell cycle dependence. These results indicate that the cytoplasmic expression system has two primary advantages over nuclear expression in that it does not rely on nuclear DNA transport or mitosis for efficient expression.
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Affiliation(s)
- M Brisson
- Department of Pharmacology, University of Pittsburgh School of Medicine, PA 15261, USA
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Yiin SJ, Chern CL, Sheu JY, Tseng WC, Lin TH. Cadmium-induced renal lipid peroxidation in rats and protection by selenium. J Toxicol Environ Health A 1999; 57:403-413. [PMID: 10478822 DOI: 10.1080/009841099157601] [Citation(s) in RCA: 59] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Cadmium has been recognized as one of the most toxic environmental and industrial pollutants. The kidney is a critical target organ following Cd exposure. The aim of this study was to investigate the effects of cadmium-induced peroxidative damage to rat kidney. Treatment of rats with Cd resulted in a time- and dose-related accumulation of metal in kidney. Cd produced enhanced lipid peroxidation in plasma and kidney. These Cd-induced changes were accompanied by a significant rise in renal Fe and Cu, and a fall in tissue Zn and Se. Concurrent treatment with Se and Cd reduced the Cd-induced alterations in renal peroxidation and essential metal levels. Data suggest that lipid peroxidation is associated with Cd toxicity and that Se was found effective in attenuation of these renal effects.
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Affiliation(s)
- S J Yiin
- Tajen Junior College of Pharmacy, Pintung, Taiwan, Republic of China
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15
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Abstract
A critical requirement of gene therapy is expression of the delivered transgene. Transgene expression is facilitated by access to the transcription mechanism found primarily in the nucleus. Factors modulating the interactions between intracellular plasmid and nuclear access are not well understood. In this study, the effect of mitosis on transgene expression was examined by quantitative flow cytometry. Transfection of HeLa cells synchronized at late G1 phase or G2/M phase was performed using a liposomal vector containing 1,2-dioleoyl-3-trimethylammonium-propane (DOTAP) and dioleoyl-phosphatidylethanolamine (DOPE) (1:1 mol/mol). Cell samples were transfected and subsequently maintained in G1 phase for various durations to modulate the time between plasmid entry and mitosis. The plasmid contains the sequence for a mutated green fluorescent protein (GFP(S65T)) that was used to examine transgene expression. Ethidium monoazide-labeled plasmid was employed to examine the association of plasmid with the cell membrane. The percentage of cells expressing GFP(S65T) increased sharply as the synchronized cell population passed through M phase, suggesting that an event associated with mitosis is essential for transgene expression. Expression levels of the transgene then declined 18 h after mitosis irrespective of transfection strategy. All transfection strategies resulted in the same maximum percentage of GFP(S65T) positive cells (40%) and average GFP(S65T) expression level (3.14x106 molecules per positive cell). Association of plasmid with the cell membrane at late G1 phase was 1.5-fold of that at G2/M phase. These data are evidence for control of transgene expression triggered by events associated with cell cycle.
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Affiliation(s)
- W C Tseng
- Department of Chemical Engineering, Vanderbilt University, Nashville, TN 37235, USA
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Li S, Tseng WC, Stolz DB, Wu SP, Watkins SC, Huang L. Dynamic changes in the characteristics of cationic lipidic vectors after exposure to mouse serum: implications for intravenous lipofection. Gene Ther 1999; 6:585-94. [PMID: 10476218 DOI: 10.1038/sj.gt.3300865] [Citation(s) in RCA: 283] [Impact Index Per Article: 11.3] [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: 11/09/2022]
Abstract
Intravenous gene delivery via cationic lipidic vectors gives systemic gene expression particularly in the lung. In order to understand the mechanism of intravenous lipofection, a systematic study was performed to investigate the interactions of lipidic vectors with mouse serum emphasizing how serum affects the biophysical and biological properties of vectors of different lipid compositions. Results from this study showed that lipidic vectors underwent dynamic changes in their characteristics after exposure to serum. Addition of lipidic vectors into serum resulted in an immediate aggregation of vectors. Prolonged incubation of lipidic vectors with serum led to vector disintegration as shown in turbidity study, sucrose-gradient centrifugation analysis and fluorescence resonance energy transfer (FRET) study. Vector disintegration was associated with DNA release and degradation as shown in EtBr intercalation assay and DNA digestion study. Serum-induced disintegration of vectors is a general phenomenon for all cationic lipidic vectors tested in this study. Yet, vectors of different lipid compositions vary greatly in the rate of disintegration. There is an inverse correlation between the disintegration rate of lipidic vectors and their in vivo transfection efficiency. Vectors with a rapid rate of disintegration such as those containing dioleoyl-phosphatidylethanolamine (DOPE) poorly stayed in the lung and were barely active in transfecting cells. In contrast, cholesterol-containing vectors that had a rapid aggregation and a slow disintegration were highly efficient in transfecting cells in vivo. The results of this study explain why cationic lipidic vectors of different lipid compositions have a dramatic difference in their in vivo transfection efficiency. These results also suggest that the study of the interactions of lipidic vectors with serum may serve as a predictive model for the in vivo efficiency of a lipidic vector. Further study of the numerous interactions of lipidic vectors with serum might lead to the development of a vector which can deliver a gene to target cells in a tissue-specific manner.
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Affiliation(s)
- S Li
- Department of Pharmacology, University of Pittsburgh School of Medicine 15261, USA
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17
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Lin TH, Tseng WC, Cheng SY. Direct determination of selenium in human blood plasma and seminal plasma by graphite furnace atomic absorption spectrophotometry and clinical application. Biol Trace Elem Res 1998; 64:133-49. [PMID: 9845468 DOI: 10.1007/bf02783330] [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] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
Direct determination of selenium (Se) in body fluids by graphite furnace atomic absorption spectrophotometry (GFAAS) may suffer from problems like severe background, matrix effects, preatomization losses, and spectral interferences. In this study we evaluate critically the influence on the accuracy of the direct determination of Se in blood plasma and seminal plasma by GFAAS, and propose a simple, rapid, and accurate method, suitable for routine clinical analysis. The method for blood plasma is mainly based on studies by the use of matched matrix and a Pd-Ni modifier, but for seminal plasma only a Pd modifier is required. The method developed was also applied to study the Se distribution in plasma protein fractions of patients with hepatocellular carcinoma. The Se in plasma of patients was significantly lower than that of the controls. The distribution pattern of Se in blood plasma fractions of patients was also different from that of the controls.
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Affiliation(s)
- T H Lin
- School of Technology for Medical Sciences, Kaohsiung Medical College, Taiwan, ROC
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18
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Tseng WC, Haselton FR, Giorgio TD. Transfection by cationic liposomes using simultaneous single cell measurements of plasmid delivery and transgene expression. J Biol Chem 1997; 272:25641-7. [PMID: 9325286 DOI: 10.1074/jbc.272.41.25641] [Citation(s) in RCA: 135] [Impact Index Per Article: 5.0] [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: 02/05/2023] Open
Abstract
Cationic liposomes are potentially important gene transfer vehicles, although their application has been limited by relatively low efficiency of transgene expression. Single cell quantitative methods, such as those used in this study, should permit a more detailed understanding of the relationships between delivered plasmid and transgene expression. Intracellular plasmid delivery and transgene expression were measured simultaneously using photoconjugated ethidium monoazide as an intracellular plasmid delivery marker and green fluorescent protein (GFP(S65T)) as a transgene expression marker. Quantitative flow cytometry was used to estimate plasmid copy number and GFP(S65T) molecules in single cells. The plasmid was delivered to HeLa cells with a cationic liposome vehicle containing 1,2-dioleoyloxy-3-trimethylammonium-propane and dioleoylphosphatidylethanolamine (1:1 mol/mol). Treatment was carried out continuously for 24 h. Flow cytometry measurements on 20, 000 cells were performed during treatment and for 48 h post-treatment. On a single cell basis, transgene expression efficiency and average GFP(S65T) expression level increased with intracellular plasmid copy number. After 3-h exposure to the liposomal vector, more than 95% of the cells were positive for plasmid entry, but none had detectable transgene expression. Maximum transgene expression was achieved at 24 h and remained unchanged at the 72-h measurement. At 24 h, the average positive cell contained 1.6 x 10(5) plasmid copies and 2.3 x 10(6) GFP(S65T) molecules. Importantly, the measurement strategies revealed that transgene expression varied widely within the entire cell population. Although only 30% of all cells expressed transgene, the subpopulation of cells that rapidly incorporated the vector demonstrated 100% efficiency in transgene expression. This study identifies parameters that modulate highly efficient transgene expression from plasmid delivery by cationic liposomes.
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Affiliation(s)
- W C Tseng
- Department of Chemical, Vanderbilt University, Nashville, Tennessee 37235, USA
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Affiliation(s)
- T H Lin
- School of Technology for Medical Sciences, Kaohsiung Medical College, Taiwan, Republic of China
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Deo SS, Tseng WC, Saini R, Coles RS, Athwal RS. Purification and characterization of Escherichia coli xanthine-guanine phosphoribosyltransferase produced by plasmid pSV2gpt. Biochim Biophys Acta 1985; 839:233-9. [PMID: 3886014 DOI: 10.1016/0304-4165(85)90003-0] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
The enzyme xanthine-guanine phosphoribosyltransferase from Escherichia coli cells harboring the plasmid pSV2gpt has been purified 30-fold to near homogeneity by single-step GMP-agarose affinity chromatography. It has a Km value of 2.5, 42 and 182 microM for the substrates guanine, xanthine and hypoxanthine, respectively, with guanine being the most preferred substrate. The enzyme exhibits a Km value of 38.5 microM for PRib-PP with guanine as second substrate and of 100 microM when xanthine is used as the second substrate. It is markedly inhibited by 6-thioguanine, GMP and to a lesser extent by some other purine analogues. Thioguanine has been found to be the most potent inhibitor. The subunit molecular weight of xanthine-guanine phosphoribosyltransferase was determined to be 19 000. The in situ activity assay on a nondenaturing polyacrylamide gel electrophoresis gel has indicated that a second E. coli phosphoribosyltransferase preferentially uses hypoxanthine as opposed to guanine as a substrate, and it does not use xanthine.
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Randerath K, Tseng WC, Harris JS, Lu LJ. Specific effects of 5-fluoropyrimidines and 5-azapyrimidines on modification of the 5 position of pyrimidines, in particular the synthesis of 5-methyluracil and 5-methylcytosine in nucleic acids. Recent Results Cancer Res 1983; 84:283-97. [PMID: 6189160 DOI: 10.1007/978-3-642-81947-6_22] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
5-Fluoropyrimidines and 5-azapyrimidines were found in our laboratory to be specific inhibitors of modification reactions taking place at the 5 position of pyrimidines in nucleic acids. Thus, 5-fluorouracil and 5-fluorouridine specifically inhibit the formation of 5-methyluracil, pseudouridine, and 5,6-dihydrouracil in tRNA. 5-Fluorocytidine, which is partially biotransformed to 5-fluorouracil derivatives in mammalian cells, inhibits the formation of 5-methyluracil, pseudouridine, 5,6-dihydrouracil, and 5-methylcytosine, and 5-azacytidine is a specific inhibitor of the formation of 5-methylcytosine in tRNA and DNA. Inhibitory effects on tRNA modifications require RNA synthesis, as shown by the observation that various inhibitors of RNA synthesis block the drug effects. An inhibitory low-molecular-weight (4-7S) RNA, consisting mainly of tRNA and pre-tRNA, was isolated from livers of mice after treatment with 5-azacytidine. This RNA, when added to an in vitro tRNA methyltransferase assay, specifically interfered with the formation of 5-methylcytosine in substrate tRNA. Similarly, a DNA inhibiting the synthesis of 5-methylcytosine in an in vitro DNA methylation assay was isolated from L1210 leukemic cells treated with a high dose of 5-azacytidine for a short time. Our data are consistent with the hypothesis that incorporation of 5-azacytosine into positions that are normally occupied by C residues destined to become methylated is required for the inhibition to occur, and a similar situation probably applies to the 5-fluoropyrimidine analogs. Analog base moieties occupying such sites are likely to bind strongly, perhaps irreversibly, to the active sites of the particular modifying enzymes. All our observations with the 5-fluoro- and 5-azapyrimidines are in accord with this hypothesis. It was also observed that administration of 5-azacytidine to mice led to strong inhibition of tRNA cytosine-5-methyltransferase, while at the same time the activities and capacities of purine-specific tRNA methyltransferases became strongly elevated after an initial lag period. We speculate that such increases may represent a response of the cell to the methylation defect induced by the drug. Undermodified tRNAs present in neoplastic cells may also trigger an increased synthesis of modifying enzymes. A scheme has been presented which explains increased tRNA turnover and increased activities of modifying enzymes in neoplastic cells as a consequence of a primary defect in tRNA modification.
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Tseng WC, Derse D, Cheng YC, Brockman RW, Bennett LL. In vitro biological activity of 9-beta-D-arabinofuranosyl-2-fluoroadenine and the biochemical actions of its triphosphate on DNA polymerases and ribonucleotide reductase from HeLa cells. Mol Pharmacol 1982; 21:474-7. [PMID: 7048062] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
9-beta-D-Arabinofuranosyl-2-fluoroadenine (2-F-araA) inhibited the growth in vitro of HeLa cells by 50% at a concentration of 0.25 microM and depressed the replication of herpes simplex virus Types 1 and 2 by 99% at 25 microM. The analogue served as a substrate for cytoplasmic but not mitochondrial deoxycytidine (dCyd) kinase partially purified from human peripheral chronic lymphocytic leukemic blast cells. The Km values of dCyd and 2-F-araA for the cytoplasmic enzyme were 5 microM and 213 microM, respectively. However, at concentrations of 0.4 mM, the analogue was phosphorylated 2.9 times faster than dCyd. The 5'-triphosphate of 2-F-araA was examined for its biochemical effects on partially purified ribonucleotide reductase and highly purified DNA alpha- and beta-polymerases from HeLa cells. 2-F-araATP was a potent inhibitor of ribonucleotide reductase; the concentration required for 50% inhibition of ADP reduction (0.3 mM ADP; 5 mM GTP or dGTP) was 1 microM and for CDP reduction (0.15 mM CPD; 5 mM ATP) was 8.5 microM. Furthermore, 2-F-araATP was a competitive inhibition (Ki = 1.2 microM) with respect to dATP (Km = 3.8 microM) of DNA alpha-polymerase, whereas DNA beta-polymerase was relatively insensitive to the drug. The results suggest that the cytotoxic actions of 2-F-araA may be due, in part, to a "self-potentiating" inhibition of DNA synthesis. This is, by inhibiting the formation of competing dATP, 2-F-araATP may potentiate its inhibition of DNA synthesis.
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Tseng WC, Medina D, Randerath K. Specific inhibition of transfer RNA methylation and modification in tissues of mice treated with 5-fluorouracil. Cancer Res 1978; 38:1250-7. [PMID: 639058] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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Kupchik EJ, Pisano MA, Hanke HE, Tseng WC. Synthesis and antimicrobial activity of ethyl N-aryl-S-(triphenylstannyl)isothiocarbamates. J Pharm Sci 1978; 67:576-8. [PMID: 641779 DOI: 10.1002/jps.2600670442] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Five ethyl N-aryl-S-(triphenylstannyl)isothiocarbamates were synthesized by the reaction of triphenyltin iodide with the appropriate ethyl N-arylthiocarbamate in the presence of triethylamine. The IR spectrum of each compound was obtained over the 4000--200-cm--1 range, and some bands were assigned. These new compounds were found to be generally better antifungal agents than the previously tested N-substituted N'-cyano-S-(triphenylstannyl)isothioureas. The new compounds were also investigated for antibacterial activity and were especially inhibitory toward Gram-positive species. Except for their lower activity toward Bacillus subtilis, their antibacterial activity was identical to the previously tested N-phenyl-N'-cyano-S-(triphenylstannyl)isothiourea.
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Abstract
Administration of the pyrimidine antimetabolite, 5-fluorouridine, to mice was found to cause a marked specific reduction of the amounts of 5-methyluridine, pseudouridine, and dihydrouridine but not of 3-(3-amino-3-carboxypropyl)uridine in tRNA from the livers of the treated animals. The data presented indicate that this effect is not simply due to the incorporation of 5-fluorouridine into tRNA; the drug appears to interfere directly with the enzymic reactions involved in the modification of the 5-position of uridine. 5-Fluorouridine was found to have no effect on the modification of adenosine, guanosine, and cytidine in mouse liver tRNA.
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Affiliation(s)
- L W Lu
- Department of Pharmacology, Baylor College of Medicine, Texas Medical Center, Houston, Texas 77030, USA
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Lin SY, Huang MC, Tseng WC, Lee CY. Comparative studies on the biological activities of cardiotoxin, melittin and prymnesin. Naunyn Schmiedebergs Arch Pharmacol 1975; 287:349-58. [PMID: 167293 DOI: 10.1007/bf00500037] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The actions of cardiotoxin (CTX), melittin and prymnesin were compared on dog erythrocytes, chicken biventer cervicis muscle, rabbit conjunctiva, acetylcholinesterase, succinate-cytochrome c reductase and turbidity of the rat liver mitochondrial suspension. 1. CTX and melittin were approximately equipotent in the various biological activities, while prymnesin was not. 2. The rate of direct ehmolysis induced by CTX was slow, while that induced by either melittin or prymnesin was fast. 3. Phosphate ions, 10mM Ca++, as well as 1 mM reduced glutathione, considerably inhibited the CTX-induced hemolysis, but only slightly inhibited that induced by melittin or prymnesin. 4. CTX, melittin and prymnesin caused contracture of the chicken biventer cervicis muscle. Prymnesin was much less active in this preparation as compared with its hemolytic potency. The CTX contracture was completely inhibited by high Ca++ (10mM) medium, while the melittin contracture was not. 5. The rate of CTX contracture to reach the peak tension was increased when the concentration of CTX was increased, while the rate of melittin contracture did not change very much as the concentrations varied. 6. All three toxins caused a local irritation of the conjunctival sac of the rabbit eye. 7. Both CTX and melittin inhibited acetylcholinesterase and succinate-cytochrome c reductase activities, and also increased the turbidity of the rat liver mitochondrial suspension, while prymnesin was totally inactive in these respects. It is concluded that the mechanism of actions of these toxins may be different at the molecular level. The role of the detergent properties of these toxins in their biological activities is discussed.
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Abstract
1. Scorpion toxin II is potent in inducing contracture and spontaneous contractions of the chick biventer cervicis muscle. In addition, this toxin induces membrane depolarization and blockade of neuromuscular transmission in this muscle preparation. The purpose of the present study is to explore the possible mechanism of actions of toxin II. 2. The muscle contracture induced by toxin II is moderately accelerated by Ca2+-free Krebs solution, delayed by high Ca2+ (10 mM), high Mg2+ (10 mM) and low Na+ (60mM) Krebs solution. Moreover, this action is inhibited slightly by d-tubocurarine and completely by either procaine or tetrodotoxin, but unaffected by beta-bungarotoxin. All these findings suggest that toxin II induces contracture mainly by increasing the Na+ permeability of the muscle membrane. 3. Spontaneous contractions induced by toxin II are abolished by Ca2+-free Krebs solution, inhibited partially by either d-tubocurarine or beta-bungarotoxin and completely by tetrodotoxin or procaine. These results suggest that toxin II induces spontaneous contractions partially by releasing acetylcholine from nerve endings and partially by increasing the Na+ permeability of the muscle membrane.
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