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Oudiz R, Medicine UCLADGSO, Kramer M, Bartolome S, Bourge R, Ford H, Medarov B, Sager J, Shapiro S, Waxman A, Ishizawar D, Saggar R, Naeije R, Shin J, Sista P, Smart A, Di Marino M, Tomson ML, Lorber M. EFFECT OF ESUBERAPROST ON MORBIDITY AND MORTALITY IN WORLD HEALTH ORGANIZATION (WHO) FUNCTIONAL CLASS III AND IV (FC III/IV) PATIENTS WITH PULMONARY ARTERIAL HYPERTENSION: RESULTS FROM THE RANDOMIZED, DOUBLE-BLIND, PLACEBO CONTROLLED PHASE 3 TRIAL- BERAPROST-314D ADDED TO TYVASO (BEAT). Chest 2019. [DOI: 10.1016/j.chest.2019.08.1496] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022] Open
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2
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Shen L, Patel JA, Norel X, Moledina S, Whittle BJ, von Kessler K, Sista P, Clapp LH. Pharmacology of the single isomer, esuberaprost (beraprost-314d) on pulmonary vascular tone, IP receptors and human smooth muscle proliferation in pulmonary hypertension. Biochem Pharmacol 2019; 166:242-252. [DOI: 10.1016/j.bcp.2019.05.026] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2019] [Accepted: 05/29/2019] [Indexed: 12/20/2022]
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3
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Marshall A, Reuter Q, Powell E, Zaidi H, McCarthy D, Sista P, Dresden S. 288 Emergency Department-Based Palliative Interventions. Ann Emerg Med 2017. [DOI: 10.1016/j.annemergmed.2017.07.266] [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: 10/18/2022]
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Balog ERM, Ghosh K, Park YI, Hartung V, Sista P, Rocha RC, Wang HL, Martinez JS. Stimuli-Responsive Genetically Engineered Polymer Hydrogel Demonstrates Emergent Optical Responses. ACS Biomater Sci Eng 2016; 2:1135-1142. [PMID: 33465871 DOI: 10.1021/acsbiomaterials.6b00137] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Biopolymer-based optical hydrogels represent an emerging class of materials with potential applications in biocompatible integrated optoelectronic devices, bioimaging applications, and stretchable/flexible photonics. We have synthesized stimuli-responsive three-dimensional hydrogels from genetically engineered elastin-like polymers (ELPs) and have loaded these hydrogels with an amine-containing p-phenylenevinylene oligomer (OPPV) derivative featuring highly tunable, environmentally sensitive optical properties. The composite ELP/OPPV hydrogels exhibit both pH- and temperature-dependent fluorescence emission, from which we have characterized a unique optical behavior that emerged from OPPV within the hydrogel environment. By systematic comparison with free OPPV in solution, our results suggest that this distinct behavior is due to local electronic effects arising from interactions between the hydrophobic ELP microenvironment and the nonprotonated OPPV species at pH 7 or higher.
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Affiliation(s)
- Eva Rose M Balog
- Center for Integrated Nanotechnologies, Materials Physics and Applications Division, ⊥C-PCS, Chemistry Division, #MST-7, Materials Science and Technology Division, and △Institute for Materials Science, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, United States
| | - Koushik Ghosh
- Center for Integrated Nanotechnologies, Materials Physics and Applications Division, C-PCS, Chemistry Division, #MST-7, Materials Science and Technology Division, and △Institute for Materials Science, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, United States
| | - Young-Il Park
- Center for Integrated Nanotechnologies, Materials Physics and Applications Division, C-PCS, Chemistry Division, MST-7, Materials Science and Technology Division, and △Institute for Materials Science, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, United States
| | - Vaughn Hartung
- Center for Integrated Nanotechnologies, Materials Physics and Applications Division, C-PCS, Chemistry Division, MST-7, Materials Science and Technology Division, and Institute for Materials Science, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, United States
| | - Prakash Sista
- Center for Integrated Nanotechnologies, Materials Physics and Applications Division, C-PCS, Chemistry Division, MST-7, Materials Science and Technology Division, and Institute for Materials Science, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, United States
| | - Reginaldo C Rocha
- Center for Integrated Nanotechnologies, Materials Physics and Applications Division, C-PCS, Chemistry Division, MST-7, Materials Science and Technology Division, and Institute for Materials Science, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, United States
| | - Hsing-Lin Wang
- Center for Integrated Nanotechnologies, Materials Physics and Applications Division, C-PCS, Chemistry Division, MST-7, Materials Science and Technology Division, and Institute for Materials Science, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, United States
| | - Jennifer S Martinez
- Center for Integrated Nanotechnologies, Materials Physics and Applications Division, C-PCS, Chemistry Division, MST-7, Materials Science and Technology Division, and Institute for Materials Science, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, United States
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Kularatne RS, Sista P, Magurudeniya HD, Hao J, Nguyen HQ, Biewer MC, Stefan MC. Donor-acceptor semiconducting polymers based on pyromellitic diimide. ACTA ACUST UNITED AC 2015. [DOI: 10.1002/pola.27607] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Ruvini S. Kularatne
- Department of Chemistry; University of Texas at Dallas; Richardson Texas 75080
| | - Prakash Sista
- Department of Chemistry; University of Texas at Dallas; Richardson Texas 75080
| | | | - Jing Hao
- Department of Chemistry; University of Texas at Dallas; Richardson Texas 75080
| | - Hien Q. Nguyen
- Department of Chemistry; University of Texas at Dallas; Richardson Texas 75080
| | - Michael C. Biewer
- Department of Chemistry; University of Texas at Dallas; Richardson Texas 75080
| | - Mihaela C. Stefan
- Department of Chemistry; University of Texas at Dallas; Richardson Texas 75080
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Newbloom GM, Hoffmann SM, West AF, Gile MC, Sista P, Cheung HKC, Luscombe CK, Pfaendtner J, Pozzo LD. Solvatochromism and conformational changes in fully dissolved poly(3-alkylthiophene)s. Langmuir 2015; 31:458-68. [PMID: 25486225 DOI: 10.1021/la503666x] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Absorption spectroscopy is commonly utilized to probe optical properties that can be related, among other things, to the conformation of single, isolated conjugated polymer chains in solution. It is frequently suggested that changes in peak positions of optical spectra result from variations in the stiffness of polymer chains in solution because this modifies the conjugation length. In this work we utilize ultraviolet-visible (UV-vis) spectroscopy, small angle neutron scattering (SANS), and all atom molecular dynamic (AA-MD) simulations to closely probe the relationship between the conformation of single-chains of poly(3-alkylthiophene)s (P3ATs) and their optical properties. SANS results show variations in the radius of gyration and Kuhn length as a function of alkyl chain length, and structure, as well as the solvent environment. Furthermore, both SANS and MD simulations show that dissolved P3HT chains are more rigid in solvents where self-assembly and crystallization are possible. Shifts in P3AT optical properties were also observed for different solvent environments. However, these changes were not correlated to the changes in polymer conformation. Furthermore, changes in optical properties could not be perfectly described by generalized solvent-solute interactions. AA-MD simulations provide new insights into specific polymer-solvent interactions not accounted for in generalized solvatochromic theory. This work highlights the need for experiments and molecular simulations that further inform the specific role of solvent molecules on local polymer conformation and on optical properties.
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Affiliation(s)
- Gregory M Newbloom
- Department of Chemical Engineering, University of Washington , Box 351750, Seattle, Washington 98195-1750, United States
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Snyder CR, Nieuwendaal RC, DeLongchamp DM, Luscombe CK, Sista P, Boyd SD. Quantifying Crystallinity in High Molar Mass Poly(3-hexylthiophene). Macromolecules 2014. [DOI: 10.1021/ma500136d] [Citation(s) in RCA: 80] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Affiliation(s)
- Chad R. Snyder
- Materials
Science and Engineering Division, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, United States
| | - Ryan C. Nieuwendaal
- Materials
Science and Engineering Division, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, United States
| | - Dean M. DeLongchamp
- Materials
Science and Engineering Division, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, United States
| | - Christine K. Luscombe
- Materials
Science and Engineering Department, University of Washington, Seattle, Washington 98195, United States
| | - Prakash Sista
- Materials
Science and Engineering Department, University of Washington, Seattle, Washington 98195, United States
| | - Shane D. Boyd
- Materials
Science and Engineering Department, University of Washington, Seattle, Washington 98195, United States
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Abstract
Polythiophene and its derivatives have shown tremendous potential for interfacing electrically conducting polymers with biological applications. These semiconducting organic polymers are relatively soft, conduct electrons and ions, have low cytotoxicity, and can undergo facile chemical modifications. In addition, the reduction in electrical impedance of electrodes coated with polythiophenes may prove to be invaluable for a stable and permanent connection between devices and biological tissues. This review article focuses on the synthesis and some key applications of polythiophenes in multidisciplinary areas at the interface with biology. These polymers have shown tremendous potential in biological applications such as diagnostics, therapy, drug delivery, imaging, implant devices and artificial organs.
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Sista P, Kularatne RS, Mulholland ME, Wilson M, Holmes N, Zhou X, Dastoor PC, Belcher W, Rasmussen SC, Biewer MC, Stefan MC. Synthesis and photovoltaic performance of donor-acceptor polymers containing benzo[1,2-b:4,5-b′]dithiophene with thienyl substituents. ACTA ACUST UNITED AC 2013. [DOI: 10.1002/pola.26650] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Prakash Sista
- Department of Chemistry; University of Texas at Dallas; Richardson; Texas; 75080
| | - Ruvini S. Kularatne
- Department of Chemistry; University of Texas at Dallas; Richardson; Texas; 75080
| | - Michael E. Mulholland
- Department of Chemistry and Biochemistry; North Dakota State University; Fargo; North Dakota; 58108
| | - Mitchell Wilson
- Centre for Organic Electronics, School of Mathematical and Physical Sciences; The University of Newcastle; Callaghan; New South Wales; 2308; Australia
| | - Natalie Holmes
- Centre for Organic Electronics, School of Mathematical and Physical Sciences; The University of Newcastle; Callaghan; New South Wales; 2308; Australia
| | - Xiaojing Zhou
- Centre for Organic Electronics, School of Mathematical and Physical Sciences; The University of Newcastle; Callaghan; New South Wales; 2308; Australia
| | - Paul C. Dastoor
- Centre for Organic Electronics, School of Mathematical and Physical Sciences; The University of Newcastle; Callaghan; New South Wales; 2308; Australia
| | - Warwick Belcher
- Centre for Organic Electronics, School of Mathematical and Physical Sciences; The University of Newcastle; Callaghan; New South Wales; 2308; Australia
| | - Seth C. Rasmussen
- Department of Chemistry and Biochemistry; North Dakota State University; Fargo; North Dakota; 58108
| | - Michael C. Biewer
- Department of Chemistry; University of Texas at Dallas; Richardson; Texas; 75080
| | - Mihaela C. Stefan
- Department of Chemistry; University of Texas at Dallas; Richardson; Texas; 75080
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Elkassih SA, Sista P, Magurudeniya HD, Papadimitratos A, Zakhidov AA, Biewer MC, Stefan MC. Phenothiazine Semiconducting Polymer for Light-Emitting Diodes. MACROMOL CHEM PHYS 2012. [DOI: 10.1002/macp.201200642] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Affiliation(s)
- Ruvini S. Kularatne
- Department of Chemistry, University of Texas at Dallas, Richardson, Texas 75080
| | | | - Prakash Sista
- Department of Chemistry, University of Texas at Dallas, Richardson, Texas 75080
| | - Michael C. Biewer
- Department of Chemistry, University of Texas at Dallas, Richardson, Texas 75080
| | - Mihaela C. Stefan
- Department of Chemistry, University of Texas at Dallas, Richardson, Texas 75080
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13
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Kularatne RS, Sista P, Nguyen HQ, Bhatt MP, Biewer MC, Stefan MC. Donor–Acceptor Semiconducting Polymers Containing Benzodithiophene with Bithienyl Substituents. Macromolecules 2012. [DOI: 10.1021/ma301624t] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Ruvini S. Kularatne
- Department of Chemistry, University of Texas at Dallas, 800 West Campbell Road,
Richardson, Texas 75080, United States
| | - Prakash Sista
- Department of Chemistry, University of Texas at Dallas, 800 West Campbell Road,
Richardson, Texas 75080, United States
| | - Hien Q. Nguyen
- Department of Chemistry, University of Texas at Dallas, 800 West Campbell Road,
Richardson, Texas 75080, United States
| | - Mahesh P. Bhatt
- Department of Chemistry, University of Texas at Dallas, 800 West Campbell Road,
Richardson, Texas 75080, United States
| | - Michael C. Biewer
- Department of Chemistry, University of Texas at Dallas, 800 West Campbell Road,
Richardson, Texas 75080, United States
| | - Mihaela C. Stefan
- Department of Chemistry, University of Texas at Dallas, 800 West Campbell Road,
Richardson, Texas 75080, United States
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Bhatt MP, Sista P, Hao J, Hundt N, Biewer MC, Stefan MC. Electronic properties-morphology correlation of a rod-rod semiconducting liquid crystalline block copolymer containing poly(3-hexylthiophene). Langmuir 2012; 28:12762-12770. [PMID: 22889166 DOI: 10.1021/la301731w] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
The influence of the solvent and annealing temperature on the field-effect mobilities and morphologies of poly(3-hexylthiophene)-b-poly(γ-benzyl-L-glutamate) (P3HT-b-PBLG) rod-rod diblock copolymer has been investigated. Thin film X-ray diffraction studies show peaks originating from both P3HT and PBLG indicating that the crystalline nature of both the blocks is conserved after the formation of the block copolymer. It has been observed that the field-effect mobilities of the diblock copolymer are independent of the annealing temperatures for thin films deposited from both 1,2,4-trichlorobenzene and chloroform solvents. The correlation between the field-effect mobility and morphology indicates that the P3HT block self-assembles at the surface SiO(2) dielectric.
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Affiliation(s)
- Mahesh P Bhatt
- Department of Chemistry, University of Texas at Dallas, 800 West Campbell Road, Richardson, Texas 75080, United States
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Sista P, Huang P, Gunathilake SS, Bhatt MP, Kularatne RS, Stefan MC, Biewer MC. Synthesis and optoelectronic properties of novel benzodifuran semiconducting polymers. ACTA ACUST UNITED AC 2012. [DOI: 10.1002/pola.26243] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Bhatt MP, Huynh MK, Sista P, Nguyen HQ, Stefan MC. Synthesis, reactivity, and optoelectronic properties of poly(3-alkenylthiophene) diblock copolymers. ACTA ACUST UNITED AC 2012. [DOI: 10.1002/pola.26095] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Sista P, Xue B, Wilson M, Holmes N, Kularatne RS, Nguyen H, Dastoor PC, Belcher W, Poole K, Janesko BG, Biewer MC, Stefan MC. Influence of the Alkyl Substituents Spacing on the Solar Cell Performance of Benzodithiophene Semiconducting Polymers. Macromolecules 2012. [DOI: 10.1021/ma202497v] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Prakash Sista
- Department
of Chemistry, University of Texas at Dallas, 800 West Campbell Road,
Richardson, Texas 75080, United States
| | - Bofei Xue
- Centre for Organic
Electronics, The University of Newcastle, University Drive, Callaghan
NSW 2308, Australia
| | - Mitchell Wilson
- Centre for Organic
Electronics, The University of Newcastle, University Drive, Callaghan
NSW 2308, Australia
| | - Natalie Holmes
- Centre for Organic
Electronics, The University of Newcastle, University Drive, Callaghan
NSW 2308, Australia
| | - Ruvini S. Kularatne
- Department
of Chemistry, University of Texas at Dallas, 800 West Campbell Road,
Richardson, Texas 75080, United States
| | - Hien Nguyen
- Department
of Chemistry, University of Texas at Dallas, 800 West Campbell Road,
Richardson, Texas 75080, United States
| | - Paul C. Dastoor
- Centre for Organic
Electronics, The University of Newcastle, University Drive, Callaghan
NSW 2308, Australia
| | - Warwick Belcher
- Centre for Organic
Electronics, The University of Newcastle, University Drive, Callaghan
NSW 2308, Australia
| | - Katelyn Poole
- Department of Chemistry, Texas Christian University, 2800 S. University Drive,
Fort Worth, Texas 76129, United
States
| | - Benjamin G. Janesko
- Department of Chemistry, Texas Christian University, 2800 S. University Drive,
Fort Worth, Texas 76129, United
States
| | - Michael C. Biewer
- Department
of Chemistry, University of Texas at Dallas, 800 West Campbell Road,
Richardson, Texas 75080, United States
| | - Mihaela C. Stefan
- Department
of Chemistry, University of Texas at Dallas, 800 West Campbell Road,
Richardson, Texas 75080, United States
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Stefan MC, Bhatt MP, Sista P, Magurudeniya HD. Grignard metathesis (GRIM) polymerization for the synthesis of conjugated block copolymers containing regioregular poly(3-hexylthiophene). Polym Chem 2012. [DOI: 10.1039/c1py00453k] [Citation(s) in RCA: 106] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
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Sista P, Biewer MC, Stefan MC. Benzo[1,2-b
:4,5-b
′]dithiophene Building Block for the Synthesis of Semiconducting Polymers. Macromol Rapid Commun 2011; 33:9-20. [DOI: 10.1002/marc.201100671] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2011] [Indexed: 11/09/2022]
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Magurudeniya HD, Sista P, Westbrook JK, Ourso TE, Nguyen K, Maher MC, Alemseghed MG, Biewer MC, Stefan MC. Nickel(II) α-Diimine Catalyst for Grignard Metathesis (GRIM) Polymerization. Macromol Rapid Commun 2011; 32:1748-52. [DOI: 10.1002/marc.201100433] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2011] [Revised: 07/15/2011] [Indexed: 11/05/2022]
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Sista P, Bhatt MP, Mccary AR, Nguyen H, Hao J, Biewer MC, Stefan MC. Enhancement of OFET performance of semiconducting polymers containing benzodithiophene upon surface treatment with organic silanes. ACTA ACUST UNITED AC 2011. [DOI: 10.1002/pola.24663] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Prakash Sista
- Department of Chemistry, University of Texas, Dallas, Richardson, Texas 75080
| | - Mahesh P. Bhatt
- Department of Chemistry, University of Texas, Dallas, Richardson, Texas 75080
| | - Ashton R. Mccary
- Department of Chemistry, University of Texas, Dallas, Richardson, Texas 75080
| | - Hien Nguyen
- Department of Chemistry, University of Texas, Dallas, Richardson, Texas 75080
| | - Jing Hao
- Department of Chemistry, University of Texas, Dallas, Richardson, Texas 75080
| | - Michael C. Biewer
- Department of Chemistry, University of Texas, Dallas, Richardson, Texas 75080
| | - Mihaela C. Stefan
- Department of Chemistry, University of Texas, Dallas, Richardson, Texas 75080
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Palaniappan K, Hundt N, Sista P, Nguyen H, Hao J, Bhatt MP, Han YY, Schmiedel EA, Sheina EE, Biewer MC, Stefan MC. Block copolymer containing poly(3-hexylthiophene) and poly(4-vinylpyridine): Synthesis and its interaction with CdSe quantum dots for hybrid organic applications. ACTA ACUST UNITED AC 2011. [DOI: 10.1002/pola.24605] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Hao J, Servello J, Sista P, Biewer MC, Stefan MC. Temperature-sensitive aliphatic polyesters: synthesis and characterization of γ-substituted caprolactone monomers and polymers. ACTA ACUST UNITED AC 2011. [DOI: 10.1039/c1jm11288k] [Citation(s) in RCA: 36] [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] [Indexed: 11/21/2022]
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Hundt N, Hoang Q, Nguyen H, Sista P, Hao J, Servello J, Palaniappan K, Alemseghed M, Biewer MC, Stefan MC. Synthesis and Characterization of a Block Copolymer Containing Regioregular Poly(3-hexylthiophene) and Poly(γ-benzyl-L
-glutamate). Macromol Rapid Commun 2010; 32:302-8. [DOI: 10.1002/marc.201000502] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2010] [Revised: 09/02/2010] [Indexed: 11/10/2022]
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Sista P, Nguyen H, Murphy JW, Hao J, Dei DK, Palaniappan K, Servello J, Kularatne RS, Gnade BE, Xue B, Dastoor PC, Biewer MC, Stefan MC. Synthesis and Electronic Properties of Semiconducting Polymers Containing Benzodithiophene with Alkyl Phenylethynyl Substituents. Macromolecules 2010. [DOI: 10.1021/ma101709h] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Prakash Sista
- Departments of Chemistry and Materials Science and Engineering, University of Texas at Dallas, 800 West Campbell Road, Richardson, Texas 75080
| | - Hien Nguyen
- Departments of Chemistry and Materials Science and Engineering, University of Texas at Dallas, 800 West Campbell Road, Richardson, Texas 75080
| | - John W. Murphy
- Departments of Chemistry and Materials Science and Engineering, University of Texas at Dallas, 800 West Campbell Road, Richardson, Texas 75080
| | - Jing Hao
- Departments of Chemistry and Materials Science and Engineering, University of Texas at Dallas, 800 West Campbell Road, Richardson, Texas 75080
| | - Daniel K. Dei
- Departments of Chemistry and Materials Science and Engineering, University of Texas at Dallas, 800 West Campbell Road, Richardson, Texas 75080
| | - Kumaranand Palaniappan
- Departments of Chemistry and Materials Science and Engineering, University of Texas at Dallas, 800 West Campbell Road, Richardson, Texas 75080
| | - John Servello
- Departments of Chemistry and Materials Science and Engineering, University of Texas at Dallas, 800 West Campbell Road, Richardson, Texas 75080
| | - Ruvini S. Kularatne
- Departments of Chemistry and Materials Science and Engineering, University of Texas at Dallas, 800 West Campbell Road, Richardson, Texas 75080
| | - Bruce E. Gnade
- Departments of Chemistry and Materials Science and Engineering, University of Texas at Dallas, 800 West Campbell Road, Richardson, Texas 75080
| | - Bofei Xue
- Centre for Organic Electronics, The University of Newcastle, University Drive, Callaghan NSW 2308, Australia
| | - Paul C. Dastoor
- Centre for Organic Electronics, The University of Newcastle, University Drive, Callaghan NSW 2308, Australia
| | - Michael C. Biewer
- Departments of Chemistry and Materials Science and Engineering, University of Texas at Dallas, 800 West Campbell Road, Richardson, Texas 75080
| | - Mihaela C. Stefan
- Departments of Chemistry and Materials Science and Engineering, University of Texas at Dallas, 800 West Campbell Road, Richardson, Texas 75080
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Alemseghed MG, Servello J, Hundt N, Sista P, Biewer MC, Stefan MC. Amphiphilic Block Copolymers Containing Regioregular Poly(3-hexylthiophene) and Poly(2-ethyl-2-oxazoline). MACROMOL CHEM PHYS 2010. [DOI: 10.1002/macp.200900725] [Citation(s) in RCA: 39] [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] [Indexed: 11/06/2022]
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Hundt N, Palaniappan K, Sista P, Murphy JW, Hao J, Nguyen H, Stein E, Biewer MC, Gnade BE, Stefan MC. Synthesis and characterization of polythiophenes with alkenyl substituents. Polym Chem 2010. [DOI: 10.1039/c0py00176g] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Sista P, Wasikowski B, Lecocq P, Pattery T, Bacheler L. The HIV-1 protease resistance mutation I50L is associated with resistance to atazanavir and susceptibility to other protease inhibitors in multiple mutational contexts. J Clin Virol 2008; 42:405-8. [PMID: 18472298 DOI: 10.1016/j.jcv.2008.03.023] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2007] [Revised: 02/20/2008] [Accepted: 03/18/2008] [Indexed: 11/24/2022]
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Patel S, Sista P, Balaji PV, Sasidhar YU. β-Hairpins with native-like and non-native hydrogen bonding patterns could form during the refolding of staphylococcal nuclease. J Mol Graph Model 2006; 25:103-15. [PMID: 16386445 DOI: 10.1016/j.jmgm.2005.11.007] [Citation(s) in RCA: 10] [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] [Subscribe] [Scholar Register] [Received: 07/09/2005] [Revised: 11/19/2005] [Accepted: 11/20/2005] [Indexed: 11/29/2022]
Abstract
Refolding of staphylococcal nuclease has been studied recently by hydrogen-deuterium exchange and NMR spectroscopy. These studies infer that beta-hairpin formed by strand 2 and strand 3 connected by reverse turn forms early during the refolding of nuclease. Typically, hydrogen-deuterium exchange NMR techniques are usually carried out on a time scale of milliseconds whereas beta-hairpins are known to fold on a much shorter time scale. It follows that in the experiments, the hydrogen-deuterium exchange protection patterns could be arising from a significant population of fully formed hairpins. In order to demonstrate it is the fully formed hairpins which gives rise to the hydrogen-deuterium exchange protection patterns, we have considered molecular dynamics simulation of the peptide (21)DTVKLMYKGQPMTFR(35) from staphylococcal nuclease corresponding to the beta-hairpin region, using GROMOS96 force field under NVT conditions. Starting from unfolded conformational states, the peptide folds into hairpin conformations with native-like and non-native hydrogen bonding patterns. Subsequent to folding, equilibrium conditions prevail. The computed protection factors and atom depth values, at equilibrium, of the various amide protons agree qualitatively with experimental observations. A collection of molecules following the trajectories observed in the simulations can account for experimental observations. These simulations provide a molecular picture of the formed hairpins and their conformational features during the refolding experiments on nuclease, monitored by hydrogen-deuterium exchange.
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Affiliation(s)
- Sunita Patel
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India
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31
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Melby T, Sista P, DeMasi R, Kirkland T, Roberts N, Salgo M, Heilek-Snyder G, Cammack N, Matthews TJ, Greenberg ML. Characterization of envelope glycoprotein gp41 genotype and phenotypic susceptibility to enfuvirtide at baseline and on treatment in the phase III clinical trials TORO-1 and TORO-2. AIDS Res Hum Retroviruses 2006; 22:375-85. [PMID: 16706613 DOI: 10.1089/aid.2006.22.375] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.1] [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: 11/13/2022] Open
Abstract
Enfuvirtide (T-20) is the first entry inhibitor approved for treatment of HIV infection and acts by inhibiting conformational changes in the viral envelope protein gp41 that are necessary for fusion of the virus and host cell membranes. Here we present genotypic and phenotypic data on viral envelopes obtained at baseline (n = 627) and after 48 weeks of enfuvirtide treatment (n = 302) from patients in the TORO (T-20 versus Optimized Regimen Only)-1 and -2 phase III pivotal studies. The amino acid sequence at residues 36-45 of gp41 was highly conserved at baseline except for polymorphism of approximately 16% at position 42. Substitutions within gp41 residues 36-45 on treatment were observed in virus from 92.7% of patients who met protocol defined virological failure criteria and occurred in nearly all cases (98.8%) when decreases in susceptibility to enfuvirtide from baseline of greater than 4-fold were observed. Consistent with previous observations, a wide range of baseline susceptibilities (spanning 3 logs) was observed; however, lower in vitro baseline susceptibility was not significantly associated with a decreased virological response in vivo. Virological response was also independent of baseline coreceptor tropism and viral subtype.
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Affiliation(s)
- T Melby
- Trimeris, Durham, North Carolina, USA
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32
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Mink M, Mosier SM, Janumpalli S, Davison D, Jin L, Melby T, Sista P, Erickson J, Lambert D, Stanfield-Oakley SA, Salgo M, Cammack N, Matthews T, Greenberg ML. Impact of human immunodeficiency virus type 1 gp41 amino acid substitutions selected during enfuvirtide treatment on gp41 binding and antiviral potency of enfuvirtide in vitro. J Virol 2005; 79:12447-54. [PMID: 16160172 PMCID: PMC1211558 DOI: 10.1128/jvi.79.19.12447-12454.2005] [Citation(s) in RCA: 108] [Impact Index Per Article: 5.7] [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: 11/20/2022] Open
Abstract
Enfuvirtide (ENF), a novel human immunodeficiency virus type 1 (HIV-1) fusion inhibitor, has potent antiviral activity against HIV-1 both in vitro and in vivo. Resistance to ENF observed after in vitro passaging was associated with changes in a three-amino-acid (aa) motif, GIV, at positions 36 to 38 of gp41. Patients with ongoing viral replication while receiving ENF during clinical trials acquired substitutions within gp41 aa 36 to 45 in the first heptad repeat (HR-1) of gp41 in both population-based plasma virus sequences and proviral DNA sequences from isolates showing reduced susceptibilities to ENF. To investigate their impact on ENF susceptibility, substitutions were introduced into a modified pNL4-3 strain by site-directed mutagenesis, and the susceptibilities of mutant viruses and patient-derived isolates to ENF were tested. In general, susceptibility decreases for single substitutions were lower than those for double substitutions, and the levels of ENF resistance seen for clinical isolates were higher than those observed for the site-directed mutant viruses. The mechanism of ENF resistance was explored for a subset of the substitutions by expressing them in the context of a maltose binding protein chimera containing a portion of the gp41 ectodomain and measuring their binding affinity to fluorescein-labeled ENF. Changes in binding affinity for the mutant gp41 fusion proteins correlated with the ENF susceptibilities of viruses containing the same substitutions. The combined results support the key role of gp41 aa 36 to 45 in the development of resistance to ENF and illustrate that additional envelope regions contribute to the ENF susceptibility of fusion inhibitor-naïve viruses and resistance to ENF.
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Affiliation(s)
- M Mink
- Trimeris Inc., 3500 Paramount Parkway, Morrisville, NC 27560, USA
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33
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Bellibas SE, Siddique Z, Dorr A, Bertasso A, Sista P, Kolis SJ, Cotler S, Delora P. Pharmacokinetics of enfuvirtide in pediatric human immunodeficiency virus 1-infected patients receiving combination therapy. Pediatr Infect Dis J 2004; 23:1137-41. [PMID: 15626952] [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] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 03/01/2023]
Abstract
BACKGROUND Enfuvirtide is the first of a new class of antiretroviral agents, the fusion inhibitors. OBJECTIVES The primary objective of this analysis was to evaluate the pharmacokinetics of 2.0 mg/kg enfuvirtide in human immunodeficiency virus 1 (HIV-1)-infected children and adolescents when administered in combination with at least 3 other antiretrovirals. METHODS Twenty-five HIV-1-infected pediatric patients (5-16 years of age) enrolled in an ongoing phase I/II study were included in this analysis. Patients received enfuvirtide 2.0 mg/kg sc twice daily (bid) for at least 7 days. Blood samples were collected on day 7, and plasma concentrations of enfuvirtide and its metabolite were measured by a validated liquid chromatography-tandem mass spectrometry method. Pharmacokinetics measures [Cmax, tmax, Ctrough, and area under the concentration time curve time 0 to 12 hours (AUC12 hours)] were calculated from plasma concentration-time data by standard noncompartmental methods. RESULTS There was no significant difference between children and adolescents for enfuvirtide Cmax (6.43 versus 5.88 microg/mL), Ctrough (2.87 versus 2.98 microg/mL) and AUC12 hours (56.1 versus 52.7 hours . microg/mL). Similarly no significant differences were found when the pharmacokinetic measures were compared based on sexual maturity stages. A post hoc regression analysis based on AUC12 hours showed that body weight-adjusted dosing of enfuvirtide provides drug exposure that is independent of age group, body weight and body surface area. CONCLUSIONS Body weight-adjusted dosing of enfuvirtide, at a dose of 2.0 mg/kg sc bid, in HIV-1-infected pediatric patients at least 5 years of age, provides drug exposure comparable with that previously observed in HIV-1-infected adults after 90 mg sc bid dosing. Drug exposure in children and adolescents is independent of age group, body weight, body surface area and sexual maturity stage.
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Church JA, Hughes M, Chen J, Palumbo P, Mofenson LM, Delora P, Smith E, Wiznia A, Hawkins E, Sista P, Cunningham CK. Long term tolerability and safety of enfuvirtide for human immunodeficiency virus 1-infected children. Pediatr Infect Dis J 2004; 23:713-8. [PMID: 15295220 DOI: 10.1097/01.inf.0000133045.45316.6a] [Citation(s) in RCA: 31] [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] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
BACKGROUND Enfuvirtide, a peptide inhibitor of human immunodeficiency virus (HIV)-1-host cell membrane fusion, is the first of a new class of antiretroviral agents, the entry inhibitors. The safety and antiretroviral activity of enfuvirtide treatment of 24 weeks in HIV-1-infected children has been previously documented. Here we present the long term tolerability and safety of enfuvirtide. METHODS Fourteen children, 4 to 12 years of age, with incompletely suppressed HIV-1 infection were evaluated. Enfuvirtide was administered twice daily by subcutaneous injection. After the first 24 weeks of enfuvirtide dosing, subjects were evaluated every 8 weeks up to 96 weeks of therapy. At each visit, each subject had a physical examination and an assessment for adverse events with particular attention to evaluation of injection site reactions. Laboratory studies obtained at each visit included hematology and blood chemistry values, plasma HIV-1 RNA concentrations and CD4+ T cell counts. RESULTS Of 14 subjects, 6 completed at least 96 weeks of treatment. One child discontinued enfuvirtide after 22 days of treatment because of an aversion to injections, and 1 child electively discontinued after week 24 because of surgical complications unrelated to study drug. Four subjects discontinued study because of virologic failure, defined as an increase or persistence of plasma HIV-1 RNA 1.0 copies/mL above baseline, which occurred between >or =log10 weeks 40 and 63. Two children experienced grade 3 adverse events resulting in discontinuation of the study drug; 1 subject developed grade 3 thrombocytopenia and 1 developed grade 3 edema at weeks 65 and 77, respectively. Eleven of 14 children had local injection site reactions during the first 24 weeks of treatment, 4 of the 12 subjects who continued treatment beyond week 24 reported local reactions. Generally, these local reactions were 1- to 3-cm tender nodules that developed after the injections and lasted for 1-2 days. Twelve children developed new diagnoses during treatment with enfuvirtide. None was judged to be definitively related to the study drug. Thirty-six percent of children starting enfuvirtide had HIV-1 RNA levels > 1 log10 copies/mL below baseline levels at week 96. Children remaining on enfuvirtide for the entire 96 weeks had a median of 65 cells/mm and 9% increase in CD4+ T cells. CONCLUSIONS Enfuvirtide was generally safe and, except for a high rate of injection site reactions, well-tolerated in HIV-1-infected children for as long as 96 weeks.
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Affiliation(s)
- Joseph A Church
- Childrens Hospital Los Angeles, Division of Clinical Immunology and Allergy, CA 90027, USA.
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35
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Lu J, Sista P, Giguel F, Greenberg M, Kuritzkes DR. Relative replicative fitness of human immunodeficiency virus type 1 mutants resistant to enfuvirtide (T-20). J Virol 2004; 78:4628-37. [PMID: 15078945 PMCID: PMC387671 DOI: 10.1128/jvi.78.9.4628-4637.2004] [Citation(s) in RCA: 116] [Impact Index Per Article: 5.8] [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: 11/20/2022] Open
Abstract
Resistance to enfuvirtide (ENF; T-20), a fusion inhibitor of human immunodeficiency virus type 1 (HIV-1), is conferred by mutations in the first heptad repeat of the gp41 ectodomain. The replicative fitness of recombinant viruses carrying ENF resistance mutations was studied in growth competition assays. ENF resistance mutations, selected in vitro or in vivo, were introduced into the env gene of HIV-1(NL4-3) by site-directed mutagenesis and expressed in HIV-1 recombinants carrying sequence tags in nef. The doubling time of ENF-resistant viruses was highly correlated with decreasing ENF susceptibility (R(2) = 0.859; P < 0.001). Initial fitness experiments focused on mutants identified by in vitro selection in the presence of ENF (L. T. Rimsky, D. C. Shugars, and T. J. Matthews, J. Virol. 72:986-993, 1998). In the absence of drug, these mutants displayed reduced fitness compared to wild-type virus with a relative order of fitness of wild type > I37T > V38 M > D36S/V38 M; this order was reversed in the presence of ENF. Likewise, recombinant viruses carrying ENF resistance mutations selected in vivo displayed reduced fitness in the absence of ENF with a relative order of wild type > N42T > V38A > N42T/N43K approximately N42T/N43S > V38A/N42D approximately V38A/N42T. Fitness and ENF susceptibility were inversely correlated (r = -0.988; P < 0.001). Similar results were obtained with recombinants expressing molecularly cloned full-length env genes obtained from patient-derived HIV-1 isolates before and after ENF treatment. Further studies are needed to determine whether the reduced fitness of ENF-resistant viruses alters their pathogenicity in vivo.
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Affiliation(s)
- Jing Lu
- Section of Retroviral Therapeutics, Brigham and Women's Hospital, and Division of AIDS, Harvard Medical School, Boston, Massachusetts 02139, USA
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36
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Church JA, Cunningham C, Hughes M, Palumbo P, Mofenson LM, Delora P, Smith E, Wiznia A, Purdue L, Hawkins E, Sista P. Safety and antiretroviral activity of chronic subcutaneous administration of T-20 in human immunodeficiency virus 1-infected children. Pediatr Infect Dis J 2002; 21:653-9. [PMID: 12237598 DOI: 10.1097/00006454-200207000-00010] [Citation(s) in RCA: 35] [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] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
BACKGROUND Entry inhibitors, a new class of antiretroviral agents, interfere with the attachment, coreceptor interaction or fusion of HIV-1 with host target cells. The fusion inhibitor T-20 is the first in this new class, and the present study is the first to examine chronic s.c. administration of T-20 to HIV-1-infected children. METHODS Fourteen children, 4 to 12 years of age, with incompletely suppressed HIV-1 were studied. The median plasma viral load at baseline was 26,866 copies/ml (4.4 log10), and the median CD4 count was 523 cells/mm3. T-20 was administered twice daily by s.c. injection at 30 or 60 mg per m2 of body surface area per dose. For 7 days T-20 was added to the patients' background antiretroviral regimens; at Day 7 each subject's background therapy was changed to a regimen that was predicted to be virologically active, while T-20 was continued. Results are presented for the first 24 weeks of chronic T-20 dosing. RESULTS T-20 was generally well-tolerated. One child discontinued the drug because of aversion to injections, but no child discontinued because of adverse events. Eleven (79%) of 14 children had local injection site reactions at some time during the chronic T-20 dosing. Eleven of 14 subjects achieved the protocol-specified milestone of at least a 0.7-log10 reduction in plasma HIV-1 RNA by Day 7. In 10 subjects (71%) virologic suppression of 1.0 log10 or greater was achieved at 24 weeks; 6 subjects (43%) had viral loads <400 copies/ml and 3 (21%) had fewer than 50 copies/ml at 24 weeks. CONCLUSIONS These results indicate that a 24-week regimen of twice daily s.c. dosing of T-20 in HIV-1-infected children is safe and tolerable and that it is associated with suppression of HIV-1 replication during 24 weeks of administration.
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Affiliation(s)
- Joseph A Church
- Department of Pediatrics, Children's Hospital Los Angeles and Keck School of Medicine, University of Southern California, 90027, USA.
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37
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Lawless-Delmedico MK, Sista P, Sen R, Moore NC, Antczak JB, White JM, Greene RJ, Leanza KC, Matthews TJ, Lambert DM. Heptad-repeat regions of respiratory syncytial virus F1 protein form a six-membered coiled-coil complex. Biochemistry 2000; 39:11684-95. [PMID: 10995236 DOI: 10.1021/bi000471y] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.8] [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: 11/28/2022]
Abstract
The Respiratory Syncytial Virus (RSV) fusogenic glycoprotein F(1) was characterized using biochemical and biophysical techniques. Two heptad-repeat (HR) regions within F(1) were shown to interact. Proteinase-K digestion experiments highlight the HR1 region (located proximal to the fusion peptide sequence) of the F(1) protein to which an HR2-derived (located proximal to the membrane-spanning domain) peptide binds, thus protecting both the protein and peptide from digestion. Solution-phase analysis of HR1-derived peptides shows that these peptides adopt helical secondary structure as measured by circular dichroism. Sedimentation equilibrium studies indicate that these HR1 peptides self-associate in a monomer/trimer equilibrium with an association constant of 5.2 x 10(8) M(-2). In contrast, HR2-derived peptides form random monomers in solution. CD analysis of mixtures containing peptides from the two regions demonstrate their propensity to interact and form a very stable (T(m) = 87 degrees C), helical (86% helicity) complex comprised of three HR1 and three HR2 members.
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38
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Pilcher CD, Eron JJ, Ngo L, Dusek A, Sista P, Gleavy J, Brooks D, Venetta T, DiMassimo E, Hopkins S. Prolonged therapy with the fusion inhibitor T-20 in combination with oral antiretroviral agents in an HIV-infected individual. AIDS 1999; 13:2171-3. [PMID: 10546874 DOI: 10.1097/00002030-199910220-00024] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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39
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Sista P, Edmiston S, Darges JW, Robinson S, Burns DJ. A cell-based reporter assay for the identification of protein kinase C activators and inhibitors. Mol Cell Biochem 1994; 141:129-34. [PMID: 7891670 DOI: 10.1007/bf00926176] [Citation(s) in RCA: 10] [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: 01/27/2023]
Abstract
Transmission of extra cellular signals across biological membranes results in the generation of lipid metabolites which in turn influence specific cellular events such as cell growth or differentiation. Many of these lipid messengers can activate protein kinase C (PKC) isozymes of which one function is to perpetuate the extracellular signals to the nucleus by phosphorylating other targets proteins. We have engineered mammalian cell lines to identify and evaluate activators and inhibitors of PKC-dependent and independent signal transduction pathways. The A31 mouse fibroblast cell line, has been stably transfected with a construct containing a triplet repeat of the TPA response element (TRE) upstream of a thymidine kinase promoter fused to the human growth hormone (hGH) gene. A31 cells containing this reporter construct exhibit significant increases in hGH secretion following stimulation by phorbol esters or other mitogens. The levels of hGH secretion are modulated in this system using different pharmacological agents. We demonstrate that this assay can be used to identify specific and general inhibitors as well as activators of the signal transduction pathway mediated by PKC isozymes.
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Affiliation(s)
- P Sista
- Sphinx Pharmaceuticals Corporation, Durham, NC 27717
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40
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Doerre S, Sista P, Sun SC, Ballard DW, Greene WC. The c-rel protooncogene product represses NF-kappa B p65-mediated transcriptional activation of the long terminal repeat of type 1 human immunodeficiency virus. Proc Natl Acad Sci U S A 1993; 90:1023-7. [PMID: 8430069 PMCID: PMC45803 DOI: 10.1073/pnas.90.3.1023] [Citation(s) in RCA: 74] [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] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
The long terminal repeat (LTR) of the type 1 human immunodeficiency virus (HIV-1) and the 5' regulatory region of the gene encoding the interleukin 2 receptor alpha subunit (IL-2R alpha) share functional kappa B enhancer elements involved in the regulation of these inducible transcription units during T-cell activation. These kappa B enhancer elements are recognized by a structurally related family of interactive proteins that includes p50, p65, and the product of the c-rel protooncogene (c-Rel). Recent biochemical studies have shown that p65 and p50 form the prototypical NF-kappa B complex, which is rapidly translocated from the cytoplasm to the nucleus during T-cell activation. This intracellular signaling complex potently stimulates kappa B-directed transcription from either the HIV-1 LTR or the IL-2R alpha promoter via the strong transactivation domain present in p65. We now demonstrate that nuclear expression of human c-Rel, which is induced by either phorbol ester or tumor necrosis factor alpha with delayed kinetics relative to p65, markedly represses p65-mediated activation of these transcription units. These inhibitory effects of c-Rel correlate with its DNA-binding activity but not with its ability to heterodimerize with p50, suggesting that c-Rel inhibition involves competition with p50/p65 for occupancy of the kappa B enhancer element. Together, these findings suggest that one function of c-Rel is as a physiologic repressor of the HIV-1 LTR and IL-2R alpha promoters, serving to efficiently counter the strong transcriptional activating effects of p65.
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Affiliation(s)
- S Doerre
- Howard Hughes Medical Institute, Duke University Medical Center, Durham, NC 27710
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41
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Lee JH, Li YC, Doerre S, Sista P, Ballard DW, Greene WC, Franza BR. A member of the set of kappa B binding proteins, HIVEN86A, is a product of the human c-rel proto-oncogene. Oncogene 1991; 6:665-7. [PMID: 2030915] [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: 12/29/2022]
Abstract
HIVEN86A is an inducible member of a set of cellular proteins that specifically bind to the kappa B enhancer (Franza et al., 1987; Franza, 1988; Franza, 1990; Ballard et al., 1989; Bohnlein et al., 1988). This enhancer motif has been detected in numerous cellular and viral transcription control domains (Boshart et al., 1985; Sen & Baltimore, 1986; Nabel & Baltimore, 1987). Recently, cDNAs have been cloned (Kieran et al., 1990; Baldwin & Sharp, 1987) that encode the 50 kD DNA binding subunit of murine NF-kappa B (for review: Leonardo & Baltimore, 1989) and the closely related human kappa binding factor (KBF-1) (Kimura et al., 1986; Baldwin & Sharp, 1987). A 350 amino acid domain at the N-terminus of these proteins was found to be homologous with the v-rel oncogene from the avian reticuloendotheliosis virus, strain T (REV-T), as well as a maternal effect gene, dorsal (Kieran et al., 1990; Ghosh et al., 1990). Dorsal is known to activate transcription of certain Drosophila genes (Rushlow et al., 1987). The v-Rel oncoprotein has been identified as a transcriptional activator (Gelinas & Temin, 1988; Hannink & Temin, 1989; Bull et al., 1990) in certain assay systems and shown to be induced by the tumor promoter, phorbol 12-myristate 13-acetate (PMA) in avian cells (for review: Rice & Gilden, 1988). HIVEN86A is also inducible by PMA (Franza et al., 1987; Franza, 1988; Franza, 1990). We now demonstrate that the protein product of the human c-rel proto-oncogene is structurally identical to HIVEN86A.
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Affiliation(s)
- J H Lee
- Cold Spring Harbor Laboratory, New York 11724
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42
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Ballard DW, Walker WH, Doerre S, Sista P, Molitor JA, Dixon EP, Peffer NJ, Hannink M, Greene WC. The v-rel oncogene encodes a kappa B enhancer binding protein that inhibits NF-kappa B function. Cell 1990; 63:803-14. [PMID: 2225078 DOI: 10.1016/0092-8674(90)90146-6] [Citation(s) in RCA: 280] [Impact Index Per Article: 8.2] [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: 12/30/2022]
Abstract
Studies of NF-kappa B suggest that this enhancer binding activity corresponds to a family of at least four proteins (p50, p55, p75, and p85) differentially induced with biphasic kinetics during T cell activation. While p55 and p50 are closely related to the 50 kd DNA binding subunit of NF-kappa B, p75 and p85 exhibit DNA binding properties that distinguish them from this 50 kd polypeptide and its regulatory subunits I kappa B and p65. All four members of this kappa B-specific protein family are structurally related to the v-Rel oncoprotein and one, p85, appears identical to human c-Rel. v-Rel, but not nontransforming v-Rel mutants, binds to the kappa B enhancer and inhibits NF-kappa B-activated transcription from the IL-2 receptor alpha promoter and HIV-1 LTR. These findings suggest a Rel-related family of kappa B enhancer binding proteins and raise the possibility that the transforming activity of v-Rel is linked to its inhibitory action on cellular genes under NF-kappa B control.
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Affiliation(s)
- D W Ballard
- Howard Hughes Medical Institute, Duke University Medical Center, Durham, North Carolina 27710
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