1
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Chitta LP, Zhukov AN, Berghmans D, Peter H, Parenti S, Mandal S, Aznar Cuadrado R, Schühle U, Teriaca L, Auchère F, Barczynski K, Buchlin É, Harra L, Kraaikamp E, Long DM, Rodriguez L, Schwanitz C, Smith PJ, Verbeeck C, Seaton DB. Picoflare jets power the solar wind emerging from a coronal hole on the Sun. Science 2023; 381:867-872. [PMID: 37616348 DOI: 10.1126/science.ade5801] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2022] [Accepted: 07/14/2023] [Indexed: 08/26/2023]
Abstract
Coronal holes are areas on the Sun with open magnetic field lines. They are a source region of the solar wind, but how the wind emerges from coronal holes is not known. We observed a coronal hole using the Extreme Ultraviolet Imager on the Solar Orbiter spacecraft. We identified jets on scales of a few hundred kilometers, which last 20 to 100 seconds and reach speeds of ~100 kilometers per second. The jets are powered by magnetic reconnection and have kinetic energy in the picoflare range. They are intermittent but widespread within the observed coronal hole. We suggest that such picoflare jets could produce enough high-temperature plasma to sustain the solar wind and that the wind emerges from coronal holes as a highly intermittent outflow at small scales.
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Affiliation(s)
- L P Chitta
- Max-Planck-Institut für Sonnensystemforschung, 37077 Göttingen, Germany
| | - A N Zhukov
- Solar-Terrestrial Centre of Excellence, Solar Influences Data Analysis Centre, Royal Observatory of Belgium, 1180 Brussels, Belgium
- Skobeltsyn Institute of Nuclear Physics, Moscow State University, Moscow 119991, Russia
| | - D Berghmans
- Solar-Terrestrial Centre of Excellence, Solar Influences Data Analysis Centre, Royal Observatory of Belgium, 1180 Brussels, Belgium
| | - H Peter
- Max-Planck-Institut für Sonnensystemforschung, 37077 Göttingen, Germany
| | - S Parenti
- Institut d'Astrophysique Spatiale, Centre National de la Recherche Scientifique, Université Paris-Saclay, 91405 Orsay, France
| | - S Mandal
- Max-Planck-Institut für Sonnensystemforschung, 37077 Göttingen, Germany
| | - R Aznar Cuadrado
- Max-Planck-Institut für Sonnensystemforschung, 37077 Göttingen, Germany
| | - U Schühle
- Max-Planck-Institut für Sonnensystemforschung, 37077 Göttingen, Germany
| | - L Teriaca
- Max-Planck-Institut für Sonnensystemforschung, 37077 Göttingen, Germany
| | - F Auchère
- Institut d'Astrophysique Spatiale, Centre National de la Recherche Scientifique, Université Paris-Saclay, 91405 Orsay, France
| | - K Barczynski
- Physikalisch-Meteorologisches Observatorium Davos, World Radiation Center, 7260 Davos Dorf, Switzerland
- Eidgenössische Technische Hochschule Zürich, 8093 Zürich, Switzerland
| | - É Buchlin
- Institut d'Astrophysique Spatiale, Centre National de la Recherche Scientifique, Université Paris-Saclay, 91405 Orsay, France
| | - L Harra
- Physikalisch-Meteorologisches Observatorium Davos, World Radiation Center, 7260 Davos Dorf, Switzerland
- Eidgenössische Technische Hochschule Zürich, 8093 Zürich, Switzerland
| | - E Kraaikamp
- Solar-Terrestrial Centre of Excellence, Solar Influences Data Analysis Centre, Royal Observatory of Belgium, 1180 Brussels, Belgium
| | - D M Long
- Mullard Space Science Laboratory, University College London, Dorking, Surrey RH5 6NT, UK
- Astrophysics Research Centre, School of Mathematics and Physics, Queen's University Belfast, Belfast BT7 1NN, Northern Ireland, UK
| | - L Rodriguez
- Solar-Terrestrial Centre of Excellence, Solar Influences Data Analysis Centre, Royal Observatory of Belgium, 1180 Brussels, Belgium
| | - C Schwanitz
- Physikalisch-Meteorologisches Observatorium Davos, World Radiation Center, 7260 Davos Dorf, Switzerland
- Eidgenössische Technische Hochschule Zürich, 8093 Zürich, Switzerland
| | - P J Smith
- Mullard Space Science Laboratory, University College London, Dorking, Surrey RH5 6NT, UK
| | - C Verbeeck
- Solar-Terrestrial Centre of Excellence, Solar Influences Data Analysis Centre, Royal Observatory of Belgium, 1180 Brussels, Belgium
| | - D B Seaton
- Southwest Research Institute, Boulder, CO 80302, USA
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2
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Cheng X, Priest ER, Li HT, Chen J, Aulanier G, Chitta LP, Wang YL, Peter H, Zhu XS, Xing C, Ding MD, Solanki SK, Berghmans D, Teriaca L, Aznar Cuadrado R, Zhukov AN, Guo Y, Long D, Harra L, Smith PJ, Rodriguez L, Verbeeck C, Barczynski K, Parenti S. Author Correction: Ultra-high-resolution observations of persistent null-point reconnection in the solar corona. Nat Commun 2023; 14:2372. [PMID: 37185588 PMCID: PMC10130028 DOI: 10.1038/s41467-023-38149-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/17/2023] Open
Affiliation(s)
- X Cheng
- School of Astronomy and Space Science, Nanjing University, 210093, Nanjing, China.
- Max Planck Institute for Solar System Research, 37077, Göttingen, Germany.
- Key Laboratory of Modern Astronomy and Astrophysics (Nanjing University), Ministry of Education, 210093, Nanjing, China.
| | - E R Priest
- School of Mathematics and Statistics, University of St. Andrews, Fife, KY16 9SS, Scotland, UK
| | - H T Li
- School of Astronomy and Space Science, Nanjing University, 210093, Nanjing, China
- Key Laboratory of Modern Astronomy and Astrophysics (Nanjing University), Ministry of Education, 210093, Nanjing, China
| | - J Chen
- School of Astronomy and Space Science, Nanjing University, 210093, Nanjing, China
- Key Laboratory of Modern Astronomy and Astrophysics (Nanjing University), Ministry of Education, 210093, Nanjing, China
| | - G Aulanier
- Sorbonne Université, Observatoire de Paris - PSL, École Polytechnique, IP Paris, CNRS, Laboratory for Plasma Physics (LPP), 4 place Jussieu, 75005, Paris, France
- Rosseland Centre for Solar Physics, Institute for Theoretical Astrophysics, Universitetet i Oslo, P.O. Box 1029, Blindern, 0315, Oslo, Norway
| | - L P Chitta
- Max Planck Institute for Solar System Research, 37077, Göttingen, Germany
| | - Y L Wang
- School of Astronomy and Space Science, Nanjing University, 210093, Nanjing, China
- Key Laboratory of Modern Astronomy and Astrophysics (Nanjing University), Ministry of Education, 210093, Nanjing, China
| | - H Peter
- Max Planck Institute for Solar System Research, 37077, Göttingen, Germany
| | - X S Zhu
- State Key Laboratory of Space Weather, National Space Science Center, Chinese Academy of Sciences, Beijing, China
| | - C Xing
- School of Astronomy and Space Science, Nanjing University, 210093, Nanjing, China
- Sorbonne Université, Observatoire de Paris - PSL, École Polytechnique, IP Paris, CNRS, Laboratory for Plasma Physics (LPP), 4 place Jussieu, 75005, Paris, France
| | - M D Ding
- School of Astronomy and Space Science, Nanjing University, 210093, Nanjing, China
- Key Laboratory of Modern Astronomy and Astrophysics (Nanjing University), Ministry of Education, 210093, Nanjing, China
| | - S K Solanki
- Max Planck Institute for Solar System Research, 37077, Göttingen, Germany
| | - D Berghmans
- Solar-Terrestrial Centre of Excellence - SIDC, Royal Observatory of Belgium, Ringlaan -3- Av. Circulaire, 1180, Brussels, Belgium
| | - L Teriaca
- Max Planck Institute for Solar System Research, 37077, Göttingen, Germany
| | - R Aznar Cuadrado
- Max Planck Institute for Solar System Research, 37077, Göttingen, Germany
| | - A N Zhukov
- Solar-Terrestrial Centre of Excellence - SIDC, Royal Observatory of Belgium, Ringlaan -3- Av. Circulaire, 1180, Brussels, Belgium
- Skobeltsyn Institute of Nuclear Physics, Moscow State University, 119992, Moscow, Russia
| | - Y Guo
- School of Astronomy and Space Science, Nanjing University, 210093, Nanjing, China
- Key Laboratory of Modern Astronomy and Astrophysics (Nanjing University), Ministry of Education, 210093, Nanjing, China
| | - D Long
- Mullard Space Science Laboratory, University College London, Holmbury St. Mary, Dorking, Surrey, RH5 6NT, UK
| | - L Harra
- PMOD/WRC, Dorfstrasse 33, CH-7260, Davos Dorf, Switzerland
- ETH-Zürich, Wolfang-Pauli-Strasse 27, HIT J 22.4, 8093, Zürich, Switzerland
| | - P J Smith
- Mullard Space Science Laboratory, University College London, Holmbury St. Mary, Dorking, Surrey, RH5 6NT, UK
| | - L Rodriguez
- Solar-Terrestrial Centre of Excellence - SIDC, Royal Observatory of Belgium, Ringlaan -3- Av. Circulaire, 1180, Brussels, Belgium
| | - C Verbeeck
- Solar-Terrestrial Centre of Excellence - SIDC, Royal Observatory of Belgium, Ringlaan -3- Av. Circulaire, 1180, Brussels, Belgium
| | - K Barczynski
- ETH-Zürich, Wolfang-Pauli-Strasse 27, HIT J 22.4, 8093, Zürich, Switzerland
| | - S Parenti
- Institut d'Astrophysique Spatiale, Université Paris-Saclay, 91405, Orsay Cedex, France
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3
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Cheng X, Priest ER, Li HT, Chen J, Aulanier G, Chitta LP, Wang YL, Peter H, Zhu XS, Xing C, Ding MD, Solanki SK, Berghmans D, Teriaca L, Aznar Cuadrado R, Zhukov AN, Guo Y, Long D, Harra L, Smith PJ, Rodriguez L, Verbeeck C, Barczynski K, Parenti S. Ultra-high-resolution observations of persistent null-point reconnection in the solar corona. Nat Commun 2023; 14:2107. [PMID: 37055427 PMCID: PMC10102217 DOI: 10.1038/s41467-023-37888-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2022] [Accepted: 03/30/2023] [Indexed: 04/15/2023] Open
Abstract
Magnetic reconnection is a key mechanism involved in solar eruptions and is also a prime possibility to heat the low corona to millions of degrees. Here, we present ultra-high-resolution extreme ultraviolet observations of persistent null-point reconnection in the corona at a scale of about 390 km over one hour observations of the Extreme-Ultraviolet Imager on board Solar Orbiter spacecraft. The observations show formation of a null-point configuration above a minor positive polarity embedded within a region of dominant negative polarity near a sunspot. The gentle phase of the persistent null-point reconnection is evidenced by sustained point-like high-temperature plasma (about 10 MK) near the null-point and constant outflow blobs not only along the outer spine but also along the fan surface. The blobs appear at a higher frequency than previously observed with an average velocity of about 80 km s-1 and life-times of about 40 s. The null-point reconnection also occurs explosively but only for 4 minutes, its coupling with a mini-filament eruption generates a spiral jet. These results suggest that magnetic reconnection, at previously unresolved scales, proceeds continually in a gentle and/or explosive way to persistently transfer mass and energy to the overlying corona.
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Affiliation(s)
- X Cheng
- School of Astronomy and Space Science, Nanjing University, 210093, Nanjing, China.
- Max Planck Institute for Solar System Research, 37077, Göttingen, Germany.
- Key Laboratory of Modern Astronomy and Astrophysics (Nanjing University), Ministry of Education, 210093, Nanjing, China.
| | - E R Priest
- School of Mathematics and Statistics, University of St. Andrews, Fife, KY16 9SS, Scotland, UK
| | - H T Li
- School of Astronomy and Space Science, Nanjing University, 210093, Nanjing, China
- Key Laboratory of Modern Astronomy and Astrophysics (Nanjing University), Ministry of Education, 210093, Nanjing, China
| | - J Chen
- School of Astronomy and Space Science, Nanjing University, 210093, Nanjing, China
- Key Laboratory of Modern Astronomy and Astrophysics (Nanjing University), Ministry of Education, 210093, Nanjing, China
| | - G Aulanier
- Sorbonne Université, Observatoire de Paris - PSL, École Polytechnique, IP Paris, CNRS, Laboratory for Plasma Physics (LPP), 4 place Jussieu, 75005, Paris, France
- Rosseland Centre for Solar Physics, Institute for Theoretical Astrophysics, Universitetet i Oslo, P.O. Box 1029, Blindern, 0315, Oslo, Norway
| | - L P Chitta
- Max Planck Institute for Solar System Research, 37077, Göttingen, Germany
| | - Y L Wang
- School of Astronomy and Space Science, Nanjing University, 210093, Nanjing, China
- Key Laboratory of Modern Astronomy and Astrophysics (Nanjing University), Ministry of Education, 210093, Nanjing, China
| | - H Peter
- Max Planck Institute for Solar System Research, 37077, Göttingen, Germany
| | - X S Zhu
- State Key Laboratory of Space Weather, National Space Science Center, Chinese Academy of Sciences, Beijing, China
| | - C Xing
- School of Astronomy and Space Science, Nanjing University, 210093, Nanjing, China
- Sorbonne Université, Observatoire de Paris - PSL, École Polytechnique, IP Paris, CNRS, Laboratory for Plasma Physics (LPP), 4 place Jussieu, 75005, Paris, France
| | - M D Ding
- School of Astronomy and Space Science, Nanjing University, 210093, Nanjing, China
- Key Laboratory of Modern Astronomy and Astrophysics (Nanjing University), Ministry of Education, 210093, Nanjing, China
| | - S K Solanki
- Max Planck Institute for Solar System Research, 37077, Göttingen, Germany
| | - D Berghmans
- Solar-Terrestrial Centre of Excellence - SIDC, Royal Observatory of Belgium, Ringlaan -3- Av. Circulaire, 1180, Brussels, Belgium
| | - L Teriaca
- Max Planck Institute for Solar System Research, 37077, Göttingen, Germany
| | - R Aznar Cuadrado
- Max Planck Institute for Solar System Research, 37077, Göttingen, Germany
| | - A N Zhukov
- Solar-Terrestrial Centre of Excellence - SIDC, Royal Observatory of Belgium, Ringlaan -3- Av. Circulaire, 1180, Brussels, Belgium
- Skobeltsyn Institute of Nuclear Physics, Moscow State University, 119992, Moscow, Russia
| | - Y Guo
- School of Astronomy and Space Science, Nanjing University, 210093, Nanjing, China
- Key Laboratory of Modern Astronomy and Astrophysics (Nanjing University), Ministry of Education, 210093, Nanjing, China
| | - D Long
- Mullard Space Science Laboratory, University College London, Holmbury St. Mary, Dorking, Surrey, RH5 6NT, UK
| | - L Harra
- PMOD/WRC, Dorfstrasse 33, CH-7260, Davos Dorf, Switzerland
- ETH-Zürich, Wolfang-Pauli-Strasse 27, HIT J 22.4, 8093, Zürich, Switzerland
| | - P J Smith
- Mullard Space Science Laboratory, University College London, Holmbury St. Mary, Dorking, Surrey, RH5 6NT, UK
| | - L Rodriguez
- Solar-Terrestrial Centre of Excellence - SIDC, Royal Observatory of Belgium, Ringlaan -3- Av. Circulaire, 1180, Brussels, Belgium
| | - C Verbeeck
- Solar-Terrestrial Centre of Excellence - SIDC, Royal Observatory of Belgium, Ringlaan -3- Av. Circulaire, 1180, Brussels, Belgium
| | - K Barczynski
- ETH-Zürich, Wolfang-Pauli-Strasse 27, HIT J 22.4, 8093, Zürich, Switzerland
| | - S Parenti
- Institut d'Astrophysique Spatiale, Université Paris-Saclay, 91405, Orsay Cedex, France
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4
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Miranda BH, Talwar C, Horwitz MD, Smith PJ. Aggressive paediatric camptodactyly: the evolution of a proposed treatment algorithm. J Plast Reconstr Aesthet Surg 2022; 75:1907-1915. [DOI: 10.1016/j.bjps.2022.01.020] [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] [Received: 02/23/2021] [Revised: 06/21/2021] [Accepted: 01/08/2022] [Indexed: 10/19/2022]
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5
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Carbone PS, Smith PJ, Lewis C, LeBlanc C. Promoting the Participation of Children and Adolescents With Disabilities in Sports, Recreation, and Physical Activity. Pediatrics 2021; 148:183444. [PMID: 34851421 DOI: 10.1542/peds.2021-054664] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [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] [Indexed: 11/24/2022] Open
Abstract
The benefits of physical activity are likely universal for all children, including children and adolescents with disabilities (CWD). The participation of CWD in physical activity, including adaptive or therapeutic sports and recreation, promotes inclusion, minimizes deconditioning, optimizes physical functioning, improves mental health as well as academic achievement, and enhances overall well-being. Despite these benefits, CWD face barriers to participation and have lower levels of fitness, reduced rates of participation, and a higher prevalence of overweight and obesity compared with typically developing peers. Pediatricians and caregivers may overestimate the risks or overlook the benefits of physical activity in CWD, which further limits participation. Preparticipation evaluations often include assessment of health status, functional capacity, individual activity preferences, availability of appropriate programs, and safety precautions. Given the complexity, the preparticipation evaluation for CWD may not occur in the context of a single office visit but rather over a period of time with input from the child's multidisciplinary team (physicians, coaches, physical education teachers, school nurses, adaptive recreation specialists, physical and occupational therapists, and others). Some CWD may desire to participate in organized sports to experience the challenge of competition, and others may prefer recreational activities for enjoyment. To reach the goal of inclusion in appropriate physical activities for all children with disabilities, child, family, financial, and societal barriers to participation need to be identified and addressed. Health care providers can facilitate participation by encouraging physical activity among CWD and their families during visits. Health care providers can create "physical activity prescriptions" for CWD on the basis of the child's preferred activities, functional status, need for adaptation of the activity and the recreational opportunities available in the community. This clinical report discusses the importance of participation in sports, recreation, and physical activity for CWD and offers practical suggestions to health care providers.
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Affiliation(s)
- Paul S Carbone
- Department of Pediatrics, The University of Utah, Salt Lake City, Utah
| | - Peter J Smith
- Section on Developmental and Behavioral Pediatrics, The University of Chicago, Chicago, Illinois
| | - Charron Lewis
- Division of Developmental-Behavioral Pediatrics and Psychology, Rainbow Babies and Children's Hospital, Cleveland, Ohio
| | - Claire LeBlanc
- Department of Pediatrics, McGill University, Montreal, Quebec, Canada
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6
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Onishchenko D, Huang Y, van Horne J, Smith PJ, Msall ME, Chattopadhyay I. Reduced false positives in autism screening via digital biomarkers inferred from deep comorbidity patterns. Sci Adv 2021; 7:eabf0354. [PMID: 34613766 PMCID: PMC8494294 DOI: 10.1126/sciadv.abf0354] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/29/2020] [Accepted: 08/11/2021] [Indexed: 05/13/2023]
Abstract
Here, we develop digital biomarkers for autism spectrum disorder (ASD), computed from patterns of past medical encounters, identifying children at high risk with an area under the receiver operating characteristic exceeding 80% from shortly after 2 years of age for either sex, and across two independent patient databases. We leverage uncharted ASD comorbidities, with no requirement of additional blood work, or procedures, to estimate the autism comorbid risk score (ACoR), during the earliest years when interventions are the most effective. ACoR has superior predictive performance to common questionnaire-based screenings and can reduce their current socioeconomic, ethnic, and demographic biases. In addition, we can condition on current screening scores to either halve the state-of-the-art false-positive rate or boost sensitivity to over 60%, while maintaining specificity above 95%. Thus, ACoR can significantly reduce the median diagnostic age, reducing diagnostic delays and accelerating access to evidence-based interventions.
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Affiliation(s)
| | - Yi Huang
- Department of Medicine, University of Chicago, Chicago, IL, USA
| | - James van Horne
- Department of Medicine, University of Chicago, Chicago, IL, USA
| | - Peter J. Smith
- Section of Developmental and Behavioral Pediatrics, Department of Pediatrics, University of Chicago, Chicago, IL, USA
- American Academy of Pediatrics, Itasca, IL, USA
| | - Michael E. Msall
- Section of Developmental and Behavioral Pediatrics, Department of Pediatrics, University of Chicago, Chicago, IL, USA
- Joseph P. Kennedy Research Center on Intellectual and Neurodevelopmental Disabilities, University of Chicago, Chicago, IL, USA
| | - Ishanu Chattopadhyay
- Department of Medicine, University of Chicago, Chicago, IL, USA
- Committee on Genetics, Genomics and Systems Biology, University of Chicago, Chicago, IL, USA
- Committee on Quantitative Methods in Social, Behavioral, and Health Sciences, University of Chicago, Chicago, IL, USA
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7
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Poumeaud F, Mircher C, Smith PJ, Faye PA, Sturtz FG. Deciphering the links between psychological stress, depression, and neurocognitive decline in patients with Down syndrome. Neurobiol Stress 2021; 14:100305. [PMID: 33614867 PMCID: PMC7879042 DOI: 10.1016/j.ynstr.2021.100305] [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] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2020] [Revised: 01/16/2021] [Accepted: 01/23/2021] [Indexed: 12/27/2022] Open
Abstract
The relationships between psychological stress and cognitive functions are still to be defined despite some recent progress. Clinically, we noticed that patients with Down syndrome (DS) may develop rapid neurocognitive decline and Alzheimer's disease (AD) earlier than expected, often shortly after a traumatic life event (bereavement over the leave of a primary caregiver, an assault, modification of lifestyle, or the loss of parents). Of course, individuals with DS are naturally prone to develop AD, given the triplication of chromosome 21. However, the relatively weak intensity of the stressful event and the rapid pace of cognitive decline after stress in these patients have to be noticed. It seems DS patients react to stress in a similar manner normal persons react to a very intense stress, and thereafter develop a state very much alike post-traumatic stress disorders. Unfortunately, only a few studies have studied stress-induced regression in patients with DS. Thus, we reviewed the biochemical events involved in psychological stress and found some possible links with cognitive impairment and AD. Interestingly, these links could probably be also applied to non-DS persons submitted to an intense stress. We believe these links should be further explored as a better understanding of the relationships between stress and cognition could help in many situations including individuals of the general population.
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Affiliation(s)
- François Poumeaud
- Univ. Limoges, Peripheral Neuropathies, EA6309, F-87000, Limoges, France
| | - Clotilde Mircher
- Institut Jérôme Lejeune, 37 Rue des Volontaires, F-75015, Paris, France
| | - Peter J. Smith
- University of Chicago, 950 E. 61st Street, SSC Suite 207, Chicago, IL, 60637, USA
| | - Pierre-Antoine Faye
- Univ. Limoges, Peripheral Neuropathies, EA6309, F-87000, Limoges, France
- CHU Limoges, Department of Biochemistry and Molecular Biology, F-87000, Limoges, France
| | - Franck G. Sturtz
- Univ. Limoges, Peripheral Neuropathies, EA6309, F-87000, Limoges, France
- CHU Limoges, Department of Biochemistry and Molecular Biology, F-87000, Limoges, France
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8
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Ruprecht C, Bartetzko MP, Senf D, Lakhina A, Smith PJ, Soto MJ, Oh H, Yang J, Chapla D, Varon Silva D, Clausen MH, Hahn MG, Moremen KW, Urbanowicz BR, Pfrengle F. A Glycan Array‐Based Assay for the Identification and Characterization of Plant Glycosyltransferases. Angew Chem Int Ed Engl 2020. [DOI: 10.1002/ange.202003105] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Affiliation(s)
- Colin Ruprecht
- Department of Biomolecular Systems Max Planck Institute of Colloids and Interfaces Am Mühlenberg 1 14476 Potsdam Germany
- Present address: Department of Chemistry University of Natural Resources and Life Sciences Vienna Muthgasse 18 1190 Vienna Austria
| | - Max P. Bartetzko
- Department of Biomolecular Systems Max Planck Institute of Colloids and Interfaces Am Mühlenberg 1 14476 Potsdam Germany
- Institute of Chemistry and Biochemistry Freie Universität Berlin Arnimallee 22 14195 Berlin Germany
| | - Deborah Senf
- Department of Biomolecular Systems Max Planck Institute of Colloids and Interfaces Am Mühlenberg 1 14476 Potsdam Germany
- Institute of Chemistry and Biochemistry Freie Universität Berlin Arnimallee 22 14195 Berlin Germany
| | - Anna Lakhina
- Complex Carbohydrate Research Center University of Georgia 315 Riverbend Road Athens GA 30602 USA
| | - Peter J. Smith
- Complex Carbohydrate Research Center University of Georgia 315 Riverbend Road Athens GA 30602 USA
| | - Maria J. Soto
- Complex Carbohydrate Research Center University of Georgia 315 Riverbend Road Athens GA 30602 USA
- Present address: US Department of Energy Joint Genome Institute (JGI) Berkeley CA 94702 USA
| | - Hyunil Oh
- Department of Biomolecular Systems Max Planck Institute of Colloids and Interfaces Am Mühlenberg 1 14476 Potsdam Germany
- Institute of Chemistry and Biochemistry Freie Universität Berlin Arnimallee 22 14195 Berlin Germany
| | - Jeong‐Yeh Yang
- Complex Carbohydrate Research Center University of Georgia 315 Riverbend Road Athens GA 30602 USA
| | - Digantkumar Chapla
- Complex Carbohydrate Research Center University of Georgia 315 Riverbend Road Athens GA 30602 USA
| | - Daniel Varon Silva
- Department of Biomolecular Systems Max Planck Institute of Colloids and Interfaces Am Mühlenberg 1 14476 Potsdam Germany
| | - Mads H. Clausen
- Center for Nanomedicine and Theranostics Department of Chemistry Technical University of Denmark Kemitorvet 207 2800 Kgs. Lyngby Denmark
| | - Michael G. Hahn
- Complex Carbohydrate Research Center University of Georgia 315 Riverbend Road Athens GA 30602 USA
| | - Kelley W. Moremen
- Complex Carbohydrate Research Center University of Georgia 315 Riverbend Road Athens GA 30602 USA
| | - Breeanna R. Urbanowicz
- Complex Carbohydrate Research Center University of Georgia 315 Riverbend Road Athens GA 30602 USA
| | - Fabian Pfrengle
- Department of Biomolecular Systems Max Planck Institute of Colloids and Interfaces Am Mühlenberg 1 14476 Potsdam Germany
- Institute of Chemistry and Biochemistry Freie Universität Berlin Arnimallee 22 14195 Berlin Germany
- Present address: Department of Chemistry University of Natural Resources and Life Sciences Vienna Muthgasse 18 1190 Vienna Austria
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9
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Ruprecht C, Bartetzko MP, Senf D, Lakhina A, Smith PJ, Soto MJ, Oh H, Yang J, Chapla D, Varon Silva D, Clausen MH, Hahn MG, Moremen KW, Urbanowicz BR, Pfrengle F. A Glycan Array-Based Assay for the Identification and Characterization of Plant Glycosyltransferases. Angew Chem Int Ed Engl 2020; 59:12493-12498. [PMID: 32396713 PMCID: PMC7383710 DOI: 10.1002/anie.202003105] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [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: 02/29/2020] [Revised: 04/22/2020] [Indexed: 12/19/2022]
Abstract
Growing plants with modified cell wall compositions is a promising strategy to improve resistance to pathogens, increase biomass digestibility, and tune other important properties. In order to alter biomass architecture, a detailed knowledge of cell wall structure and biosynthesis is a prerequisite. We report here a glycan array-based assay for the high-throughput identification and characterization of plant cell wall biosynthetic glycosyltransferases (GTs). We demonstrate that different heterologously expressed galactosyl-, fucosyl-, and xylosyltransferases can transfer azido-functionalized sugar nucleotide donors to selected synthetic plant cell wall oligosaccharides on the array and that the transferred monosaccharides can be visualized "on chip" by a 1,3-dipolar cycloaddition reaction with an alkynyl-modified dye. The opportunity to simultaneously screen thousands of combinations of putative GTs, nucleotide sugar donors, and oligosaccharide acceptors will dramatically accelerate plant cell wall biosynthesis research.
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Affiliation(s)
- Colin Ruprecht
- Department of Biomolecular SystemsMax Planck Institute of Colloids and InterfacesAm Mühlenberg 114476PotsdamGermany
- Present address: Department of ChemistryUniversity of Natural Resources and Life Sciences ViennaMuthgasse 181190ViennaAustria
| | - Max P. Bartetzko
- Department of Biomolecular SystemsMax Planck Institute of Colloids and InterfacesAm Mühlenberg 114476PotsdamGermany
- Institute of Chemistry and BiochemistryFreie Universität BerlinArnimallee 2214195BerlinGermany
| | - Deborah Senf
- Department of Biomolecular SystemsMax Planck Institute of Colloids and InterfacesAm Mühlenberg 114476PotsdamGermany
- Institute of Chemistry and BiochemistryFreie Universität BerlinArnimallee 2214195BerlinGermany
| | - Anna Lakhina
- Complex Carbohydrate Research CenterUniversity of Georgia315 Riverbend RoadAthensGA30602USA
| | - Peter J. Smith
- Complex Carbohydrate Research CenterUniversity of Georgia315 Riverbend RoadAthensGA30602USA
| | - Maria J. Soto
- Complex Carbohydrate Research CenterUniversity of Georgia315 Riverbend RoadAthensGA30602USA
- Present address: US Department of Energy Joint Genome Institute (JGI)BerkeleyCA94702USA
| | - Hyunil Oh
- Department of Biomolecular SystemsMax Planck Institute of Colloids and InterfacesAm Mühlenberg 114476PotsdamGermany
- Institute of Chemistry and BiochemistryFreie Universität BerlinArnimallee 2214195BerlinGermany
| | - Jeong‐Yeh Yang
- Complex Carbohydrate Research CenterUniversity of Georgia315 Riverbend RoadAthensGA30602USA
| | - Digantkumar Chapla
- Complex Carbohydrate Research CenterUniversity of Georgia315 Riverbend RoadAthensGA30602USA
| | - Daniel Varon Silva
- Department of Biomolecular SystemsMax Planck Institute of Colloids and InterfacesAm Mühlenberg 114476PotsdamGermany
| | - Mads H. Clausen
- Center for Nanomedicine and TheranosticsDepartment of ChemistryTechnical University of DenmarkKemitorvet 2072800 Kgs.LyngbyDenmark
| | - Michael G. Hahn
- Complex Carbohydrate Research CenterUniversity of Georgia315 Riverbend RoadAthensGA30602USA
| | - Kelley W. Moremen
- Complex Carbohydrate Research CenterUniversity of Georgia315 Riverbend RoadAthensGA30602USA
| | - Breeanna R. Urbanowicz
- Complex Carbohydrate Research CenterUniversity of Georgia315 Riverbend RoadAthensGA30602USA
| | - Fabian Pfrengle
- Department of Biomolecular SystemsMax Planck Institute of Colloids and InterfacesAm Mühlenberg 114476PotsdamGermany
- Institute of Chemistry and BiochemistryFreie Universität BerlinArnimallee 2214195BerlinGermany
- Present address: Department of ChemistryUniversity of Natural Resources and Life Sciences ViennaMuthgasse 181190ViennaAustria
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10
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Van de Walle T, Boone M, Van Puyvelde J, Combrinck J, Smith PJ, Chibale K, Mangelinckx S, D'hooghe M. Synthesis and biological evaluation of novel quinoline-piperidine scaffolds as antiplasmodium agents. Eur J Med Chem 2020; 198:112330. [PMID: 32408064 PMCID: PMC7294232 DOI: 10.1016/j.ejmech.2020.112330] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [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: 03/24/2020] [Revised: 04/10/2020] [Accepted: 04/10/2020] [Indexed: 01/09/2023]
Abstract
The parasitic disease malaria places almost half of the world's population at risk of infection and is responsible for more than 400,000 deaths each year. The first-line treatment, artemisinin combination therapies (ACT) regimen, is under threat due to emerging resistance of Plasmodium falciparum strains in e.g. the Mekong delta. Therefore, the development of new antimalarial agents is crucial in order to circumvent the growing resistance. Chloroquine, the long-established antimalarial drug, still serves as model compound for the design of new quinoline analogues, resulting in numerous new active derivatives against chloroquine-resistant P. falciparum strains over the past twenty years. In this work, a set of functionalized quinoline analogues, decorated with a modified piperidine-containing side chain, was synthesized. Both amino- and (aminomethyl)quinolines were prepared, resulting in a total of 18 novel quinoline-piperidine conjugates representing four different chemical series. Evaluation of their in vitro antiplasmodium activity against a CQ-sensitive (NF54) and a CQ-resistant (K1) strain of P. falciparum unveiled highly potent activities in the nanomolar range against both strains for five 4-aminoquinoline derivatives. Moreover, no cytotoxicity was observed for all active compounds at the maximum concentration tested. These five new aminoquinoline hit structures are therefore of considerable value for antimalarial research and have the potency to be transformed into novel antimalarial agents upon further hit-to-lead optimization studies.
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Affiliation(s)
- Tim Van de Walle
- SynBioC Research Group, Department of Green Chemistry and Technology, Faculty of Bioscience Engineering, Ghent University, Coupure Links 653, B-9000, Ghent, Belgium
| | - Maya Boone
- SynBioC Research Group, Department of Green Chemistry and Technology, Faculty of Bioscience Engineering, Ghent University, Coupure Links 653, B-9000, Ghent, Belgium
| | - Julie Van Puyvelde
- SynBioC Research Group, Department of Green Chemistry and Technology, Faculty of Bioscience Engineering, Ghent University, Coupure Links 653, B-9000, Ghent, Belgium
| | - Jill Combrinck
- Division of Clinical Pharmacology, Department of Medicine, Medical School, University of Cape Town, K45, OMB, Groote Schuur Hospital, Observatory, 7925, South Africa; Wellcome Centre for Infectious Diseases Research in Africa, Institute of Infectious Disease and Molecular Medicine, South Africa
| | - Peter J Smith
- Division of Clinical Pharmacology, Department of Medicine, Medical School, University of Cape Town, K45, OMB, Groote Schuur Hospital, Observatory, 7925, South Africa
| | - Kelly Chibale
- South African Medical Research Council Drug Discovery and Development Research Unit, Department of Chemistry and Institute of Infectious Disease & Molecular Medicine, University of Cape Town, Rondebosch, 7701, South Africa
| | - Sven Mangelinckx
- SynBioC Research Group, Department of Green Chemistry and Technology, Faculty of Bioscience Engineering, Ghent University, Coupure Links 653, B-9000, Ghent, Belgium
| | - Matthias D'hooghe
- SynBioC Research Group, Department of Green Chemistry and Technology, Faculty of Bioscience Engineering, Ghent University, Coupure Links 653, B-9000, Ghent, Belgium.
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11
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Prabhakar PK, Wang HT, Smith PJ, Yang JY, Barnes WJ, Peña MJ, Moremen KW, Urbanowicz BR. Heterologous expression of plant glycosyltransferases for biochemistry and structural biology. Methods Cell Biol 2020; 160:145-165. [PMID: 32896313 PMCID: PMC7593805 DOI: 10.1016/bs.mcb.2020.05.002] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/05/2022]
Abstract
Much of the carbon captured by photosynthesis is converted into the polysaccharides that constitute plant cell walls. These complex macrostructures are composed of cellulose, hemicellulose, and pectins, together with small amounts of structural proteins, minerals, and in many cases lignin. Wall components assemble and interact with one another to produce dynamic structures with many capabilities, including providing mechanical support to plant structures and determining plant cell shape and size. Despite their abundance, major gaps in our knowledge of the synthesis of the building blocks of these polymers remain, largely due to ineffective methods for expression and purification of active synthetic enzymes for in vitro biochemical analyses. The hemicellulosic polysaccharide, xyloglucan, comprises up to 25% of the dry weight of primary cell walls in plants. Most of the knowledge about the glycosyltransferases (GTs) involved in the xyloglucan biosynthetic pathway has been derived from the identification and carbohydrate analysis of knockout mutants, lending little information on how the catalytic biosynthesis of xyloglucan occurs in planta. In this chapter we describe methods for the heterologous expression of plant GTs using the HEK293 expression platform. As a demonstration of the utility of this platform, nine xyloglucan-relevant GTs from three different CAZy families were evaluated, and methods for expression, purification, and construct optimization are described for biochemical and structural characterization.
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Affiliation(s)
- Pradeep K Prabhakar
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA, United States; Complex Carbohydrate Research Center, University of Georgia, Athens, GA, United States; Center for Bioenergy Innovation, Oak Ridge National Laboratory, Oakridge, TN, United States
| | - Hsin-Tzu Wang
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA, United States; Complex Carbohydrate Research Center, University of Georgia, Athens, GA, United States; Center for Bioenergy Innovation, Oak Ridge National Laboratory, Oakridge, TN, United States
| | - Peter J Smith
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA, United States; Complex Carbohydrate Research Center, University of Georgia, Athens, GA, United States; Center for Bioenergy Innovation, Oak Ridge National Laboratory, Oakridge, TN, United States
| | - Jeong-Yeh Yang
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA, United States; Complex Carbohydrate Research Center, University of Georgia, Athens, GA, United States
| | - William J Barnes
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA, United States; Complex Carbohydrate Research Center, University of Georgia, Athens, GA, United States
| | - Maria J Peña
- Complex Carbohydrate Research Center, University of Georgia, Athens, GA, United States; Center for Bioenergy Innovation, Oak Ridge National Laboratory, Oakridge, TN, United States
| | - Kelley W Moremen
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA, United States; Complex Carbohydrate Research Center, University of Georgia, Athens, GA, United States
| | - Breeanna R Urbanowicz
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA, United States; Complex Carbohydrate Research Center, University of Georgia, Athens, GA, United States; Center for Bioenergy Innovation, Oak Ridge National Laboratory, Oakridge, TN, United States.
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12
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Smith PJ, O'Neill MA, Backe J, York WS, Peña MJ, Urbanowicz BR. Analytical Techniques for Determining the Role of Domain of Unknown Function 579 Proteins in the Synthesis of O-Methylated Plant Polysaccharides. SLAS Technol 2020; 25:345-355. [PMID: 32204644 DOI: 10.1177/2472630320912692] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Matrix polysaccharides are a diverse group of structurally complex carbohydrates and account for a large portion of the biomass consumed as food or used to produce fuels and materials. Glucuronoxylan and arabinogalactan protein are matrix glycans that have sidechains decorated with 4-O-methyl glucuronosyl residues. Methylation is a key determinant of the physical properties of these wall glycopolymers and consequently affects both their biological function and ability to interact with other wall polymers. Indeed, there is increasing interest in determining the distribution and abundance of methyl-etherified polysaccharides in different plant species, tissues, and developmental stages. There is also a need to understand the mechanisms involved in their biosynthesis. Members of the Domain of Unknown Function (DUF) 579 family have been demonstrated to have a role in the biosynthesis of methyl-etherified glycans. Here we describe methods for the analysis of the 4-O-methyl glucuronic acid moieties that are present in sidechains of arabinogalactan proteins. These methods are then applied toward the analysis of loss-of-function mutants of two DUF579 family members that lack this modification in muro. We also present a procedure to assay DUF579 family members for enzymatic activity in vitro using acceptor oligosaccharides prepared from xylan of loss-of-function mutants. Our approach facilitates the characterization of enzymes that modify glycosyl residues during cell wall synthesis and the structures that they generate.
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Affiliation(s)
- Peter J Smith
- Complex Carbohydrate Research Center, University of Georgia, Athens, GA, USA.,Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA, USA.,Center for Bioenergy Innovation (CBI), Oak Ridge National Laboratory, OakRidge, TN, USA
| | - Malcolm A O'Neill
- Complex Carbohydrate Research Center, University of Georgia, Athens, GA, USA
| | - Jason Backe
- Complex Carbohydrate Research Center, University of Georgia, Athens, GA, USA.,Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA, USA.,Center for Bioenergy Innovation (CBI), Oak Ridge National Laboratory, OakRidge, TN, USA
| | - William S York
- Complex Carbohydrate Research Center, University of Georgia, Athens, GA, USA.,Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA, USA.,Center for Bioenergy Innovation (CBI), Oak Ridge National Laboratory, OakRidge, TN, USA
| | - Maria J Peña
- Complex Carbohydrate Research Center, University of Georgia, Athens, GA, USA.,Center for Bioenergy Innovation (CBI), Oak Ridge National Laboratory, OakRidge, TN, USA
| | - Breeanna R Urbanowicz
- Complex Carbohydrate Research Center, University of Georgia, Athens, GA, USA.,Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA, USA.,Center for Bioenergy Innovation (CBI), Oak Ridge National Laboratory, OakRidge, TN, USA
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13
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Minić A, Van de Walle T, Van Hecke K, Combrinck J, Smith PJ, Chibale K, D'hooghe M. Design and synthesis of novel ferrocene-quinoline conjugates and evaluation of their electrochemical and antiplasmodium properties. Eur J Med Chem 2019; 187:111963. [PMID: 31865015 DOI: 10.1016/j.ejmech.2019.111963] [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: 09/16/2019] [Revised: 11/26/2019] [Accepted: 12/10/2019] [Indexed: 02/06/2023]
Abstract
The tropical disease malaria is responsible for more than 400,000 deaths annually, especially in Southeast Asia and Africa. Although the number of malaria cases is declining, there still is an urgent need for novel antimalarial agents. The emergence of hybrid antimalarial agents and the precedence set by the antimalarial drug ferroquine (FQ) prompted us to design new ferrocene-containing quinoline structures. Herein, we report the efficient synthesis of three different series of ferrocene-quinoline conjugates and a class of ferrocene-containing heterotricycles in good to high yields. For all twenty novel ferrocenyl derivatives, electrochemical properties were investigated using cyclic voltammetry and antiplasmodium evaluation against a chloroquine-susceptible NF54 strain of the human malaria parasite Plasmodium falciparum was conducted, pointing to three compounds showing submicromolar potency. Subsequently, cytotoxicity assays against a Chinese Hamster Ovarian cell line and evaluation against a chloroquine-resistant strain of Plasmodium falciparum for these three compounds revealed selective and promising antiplasmodium activity.
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Affiliation(s)
- Aleksandra Minić
- Faculty of Technical Sciences, University of Priština, Knjaza Miloša 7, 38220, Kosovska Mitrovica, Serbia; SynBioC Research Group, Department of Green Chemistry and Technology, Faculty of Bioscience Engineering, Ghent University, Coupure Links 653, B-9000, Ghent, Belgium.
| | - Tim Van de Walle
- SynBioC Research Group, Department of Green Chemistry and Technology, Faculty of Bioscience Engineering, Ghent University, Coupure Links 653, B-9000, Ghent, Belgium
| | - Kristof Van Hecke
- XStruct, Department of Chemistry, Faculty of Sciences, Ghent University, Krijgslaan 281, S3, B-9000, Ghent, Belgium
| | - Jill Combrinck
- Medical School, University of Cape Town, K45, OMB, Groote Schuur Hopsital, Obervatory, 7925, South Africa; Wellcome Centre for Infectious Diseases Research in Africa, Institute of Infectious Disease and Molecular Medicine, South Africa
| | - Peter J Smith
- Medical School, University of Cape Town, K45, OMB, Groote Schuur Hopsital, Obervatory, 7925, South Africa
| | - Kelly Chibale
- South African Medical Research Council Drug Discovery and Development Research Unit, Department of Chemistry and Institute of Infectious Disease and Molecular Medicine, University of Cape Town, Rondebosch, 7701, South Africa
| | - Matthias D'hooghe
- SynBioC Research Group, Department of Green Chemistry and Technology, Faculty of Bioscience Engineering, Ghent University, Coupure Links 653, B-9000, Ghent, Belgium.
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14
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Woodland JG, Hunter R, Smith PJ, Egan TJ. Chemical Proteomics and Super-resolution Imaging Reveal That Chloroquine Interacts with Plasmodium falciparum Multidrug Resistance-Associated Protein and Lipids. ACS Chem Biol 2018; 13:2939-2948. [PMID: 30208272 DOI: 10.1021/acschembio.8b00583] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
It is well established that chloroquine, a quinoline antimalarial, inhibits hemozoin formation in the malaria parasite. Counterintuitively, this archetypal antimalarial is also used in the treatment of diseases in which hemozoin biocrystallization does not play a role. Hence, we decided to investigate whether chloroquine possesses binding targets other than Fe(III) protoporphyrin IX in blood stage Plasmodium falciparum parasites and whether these are related to sites of accumulation within the parasite other than the digestive vacuole. A 7-nitrobenz-2-oxa-1,3-diazole (NBD)-labeled fluorescent derivative of chloroquine, especially sensitive to regions outside the digestive vacuole and retaining the antiplasmodial pharmacophore, was synthesized to investigate subcellular localization in the parasite. Super-resolution microscopy revealed association with membranes including the parasite plasma membrane, the endoplasmic reticulum, and possibly also the mitochondrion. A drug-labeled affinity matrix was then prepared to capture protein binding targets of chloroquine. SDS-PAGE revealed a single prominent band between 200 and 250 kDa from the membrane-associated fraction. Subsequent proteomic analysis revealed that this band corresponded to P. falciparum multidrug resistance-associated protein (PfMRP1). Intrigued by this finding, we demonstrated pull-down of PfMRP1 by matrices labeled with Cinchona alkaloids quinine and quinidine. While PfMRP1 has been implicated in resistance to quinolines and other antimalarials, this is the first time that these drugs have been found to bind directly to this protein. Based on previous reports, PfMRP1, the only prominent protein found to bind to quinolines in this work, is likely to modulate the activity of these antimalarials in P. falciparum rather than act as a drug target.
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Affiliation(s)
- John G. Woodland
- Department of Chemistry, University of Cape Town, Private Bag, Rondebosch, Cape Town 7701, South Africa
| | - Roger Hunter
- Department of Chemistry, University of Cape Town, Private Bag, Rondebosch, Cape Town 7701, South Africa
| | | | - Timothy J. Egan
- Department of Chemistry, University of Cape Town, Private Bag, Rondebosch, Cape Town 7701, South Africa
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15
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Smith PJ, Blumenthal JA, Hinderliter AL, Watkins LL, Hoffman BM, Sherwood A. Microvascular Endothelial Function and Neurocognition Among Adults With Major Depressive Disorder. Am J Geriatr Psychiatry 2018; 26:1061-1069. [PMID: 30093218 PMCID: PMC6165686 DOI: 10.1016/j.jagp.2018.06.011] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/27/2018] [Revised: 06/12/2018] [Accepted: 06/12/2018] [Indexed: 12/01/2022]
Abstract
BACKGROUND Cardiovascular risk factors (CVRFs) and endothelial dysfunction have been associated independently with poorer neurocognition in middle-aged adults, particularly on tests of frontal lobe function. However, to our knowledge, no studies have examined markers of microvascular dysfunction on neurocognition or the potential interaction between macro- and microvascular biomarkers on neurocognition in middle-aged and older adults with major depressive disorder (MDD). METHODS Participants included 202 adults with MDD who were not receiving mental health treatment. Microvascular endothelial function was assessed using a noninvasive marker of forearm reactive hyperemia velocity while macrovascular endothelial function was assessed using flow-mediated dilation (FMD) of the brachial artery. CVRFs were assessed using the Framingham Stroke Risk Profile and fasting lipid levels. A standardized neurocognitive assessment battery was used to assess three cognitive domains: executive function, working memory, and verbal memory. RESULTS Greater microvascular dysfunction was associated with poorer neurocognition across all three domains. Microvascular function continued to predict verbal memory performance after accounting for background factors and CVRFs. Macro- and microvascular function interacted to predict working memory performance (F = 4.511, 178, p = 0.035), with a similar nonsignificant association for executive function (F = 2.731, 178, p = 0.095), with moderate associations observed between microvascular function and neurocognition in the presence of preserved FMD (r61 = 0.40, p = 0.001), but not when FMD was impaired (r63 = -0.05, p = 0.675). CONCLUSION Greater microvascular dysfunction is associated with poorer neurocognition among middle-aged and older adults. This association was strongest in participants with preserved macrovascular function.
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Affiliation(s)
- PJ Smith
- Department of Psychiatry and Behavioral Sciences, Duke University Medical Center, Durham, NC 27710, USA
| | - JA Blumenthal
- Department of Psychiatry and Behavioral Sciences, Duke University Medical Center, Durham, NC 27710, USA
| | - AL Hinderliter
- Department of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC
| | - LL Watkins
- Department of Psychiatry and Behavioral Sciences, Duke University Medical Center, Durham, NC 27710, USA
| | - BM Hoffman
- Department of Psychiatry and Behavioral Sciences, Duke University Medical Center, Durham, NC 27710, USA
| | - A Sherwood
- Department of Psychiatry and Behavioral Sciences, Duke University Medical Center, Durham, NC 27710, USA
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16
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Woodland JG, Hunter R, Smith PJ, Egan TJ. Shining new light on ancient drugs: preparation and subcellular localisation of novel fluorescent analogues of Cinchona alkaloids in intraerythrocytic Plasmodium falciparum. Org Biomol Chem 2018; 15:589-597. [PMID: 27785512 DOI: 10.1039/c6ob02110g] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Fluorescent derivatives of the archetypal antimalarial quinine and its diastereomer, quinidine, suitable for cellular imaging have been synthesised by attaching the small extrinsic fluorophore, NBD. Interactions of these derivatives with ferriprotoporphyrin IX were evaluated to verify that insights generated by live-cell imaging were relevant to the parent molecules. These analogues are shown by confocal and super-resolution microscopy to accumulate selectively in Plasmodium falciparum. Localisation to the region corresponding to the digestive vacuole supports the putative primary role of these alkaloids as haemozoin inhibitors. Quantitative analysis revealed minimal accumulation within the nucleus, rejecting the disruption of DNA replication as a possible mode of action. While extensive localisation to phospholipid structures and associated organelles was observed, the analogues did not show evidence of association with neutral lipid bodies.
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Affiliation(s)
- John G Woodland
- Department of Chemistry, University of Cape Town, Private Bag, Rondebosch, 7701, South Africa.
| | - Roger Hunter
- Department of Chemistry, University of Cape Town, Private Bag, Rondebosch, 7701, South Africa.
| | - Peter J Smith
- Division of Clinical Pharmacology, Department of Medicine, University of Cape Town, Observatory, 7925, South Africa
| | - Timothy J Egan
- Department of Chemistry, University of Cape Town, Private Bag, Rondebosch, 7701, South Africa.
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17
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Dallabernardina P, Ruprecht C, Smith PJ, Hahn MG, Urbanowicz BR, Pfrengle F. Automated glycan assembly of galactosylated xyloglucan oligosaccharides and their recognition by plant cell wall glycan-directed antibodies. Org Biomol Chem 2018; 15:9996-10000. [PMID: 29177276 DOI: 10.1039/c7ob02605f] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
We report the automated glycan assembly of oligosaccharides related to the plant cell wall hemicellulosic polysaccharide xyloglucan. The synthesis of galactosylated xyloglucan oligosaccharides was enabled by introducing p-methoxybenzyl (PMB) as a temporary protecting group for automated glycan assembly. The generated oligosaccharides were printed as microarrays, and the binding of a collection of xyloglucan-directed monoclonal antibodies (mAbs) to the oligosaccharides was assessed. We also demonstrated that the printed glycans can be further enzymatically modified while appended to the microarray surface by Arabidopsis thaliana xyloglucan xylosyltransferase 2 (AtXXT2).
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Affiliation(s)
- Pietro Dallabernardina
- Department of Biomolecular Systems, Max Planck Institute of Colloids and Interfaces, Am Mühlenberg 1, 14476 Potsdam, Germany.
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18
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Smith PJ, Blumenthal JA, Hoffman BM, Davis RD, Palmer SM. Postoperative cognitive dysfunction and mortality following lung transplantation. Am J Transplant 2018; 18:696-703. [PMID: 29087035 PMCID: PMC5820215 DOI: 10.1111/ajt.14570] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2017] [Revised: 10/05/2017] [Accepted: 10/07/2017] [Indexed: 01/25/2023]
Abstract
Preliminary evidence suggests that postoperative cognitive dysfunction (POCD) is common after lung transplantation. The impact of POCD on clinical outcomes has yet to be studied. The association between POCD and longer-term survival was therefore examined in a pilot study of posttransplantation survivors. Forty-nine participants from a prior randomized clinical trial underwent a neurocognitive assessment battery pretransplantation and 6 months posttransplantation, including assessments of the domains of Executive Function (Trail Making Test, Stroop, Digit Span), Processing Speed (Ruff 2 and 7 Test, Digit Symbol Substitution Test), and Verbal Memory (Verbal Paired Associates, Logical Memory, Animal Naming, and Controlled Oral Word Association Test). During a 13-year follow-up, 33 (67%) participants died. Greater neurocognition was associated with longer survival (hazard ratio [HR] = 0.49 [0.25-0.96], P = .039), and this association was strongest on tests assessing Processing Speed (HR = 0.58 [0.36-0.95], P = .03) and Executive Function (HR = 0.52 [0.28-0.97], P = .040). In addition, unadjusted analyses suggested an association between greater Memory performance and lower risk of CLAD (HR = 0.54 [0.29-1.00], P = .050). Declines in Executive Function tended to be predictive of worse survival. These preliminary findings suggest that postoperative neurocognition is predictive of subsequent mortality among lung transplant recipients. Further research is needed to confirm these findings in a larger sample and to examine mechanisms responsible for this relationship.
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Affiliation(s)
- PJ Smith
- Duke University Medical Center, Department of Psychiatry and Behavioral Sciences
| | - JA Blumenthal
- Duke University Medical Center, Department of Psychiatry and Behavioral Sciences
| | - BM Hoffman
- Duke University Medical Center, Department of Psychiatry and Behavioral Sciences
| | | | - SM Palmer
- Duke University Medical Center, Department of Medicine
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Abstract
Seventeen patients with urinary diversions present for between 10 and 17 years were examined endoscopically. The region of the anastomosis was successfully biopsied in 13 cases. Biopsy specimens were examined both histologically and cytologically. Urine was aspirated from the conduits under sterile conditions and sent for qualification of bacterial flora. Histology revealed a variable degree of villous atrophy, mucosal metaplasia, crypt hyperplasia and in one case, antral type gland metaplasia. The finding of hyperplasia was corroborated by flow cytometry which demonstrated a high percentage of cells in G2 and metaphase. The majority of cases showed a colonic type of bacterial colonization and mucin histochemistry demonstrated a colonic type of mucin.
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Affiliation(s)
- D J Thomas
- Department of Urology, Bristol Royal Infirmary
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20
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Abstract
Two cases are reported of ureteric obstruction due to retroperitoneal fibrosis following the use of intravesical formalin. This particular complication of this treatment has not previously been described.
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21
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Ruprecht C, Dallabernardina P, Smith PJ, Urbanowicz BR, Pfrengle F. Analyzing Xyloglucan Endotransglycosylases by Incorporating Synthetic Oligosaccharides into Plant Cell Walls. Chembiochem 2018; 19:793-798. [PMID: 29384258 DOI: 10.1002/cbic.201700638] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [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: 12/01/2017] [Indexed: 12/29/2022]
Abstract
The plant cell wall is a cellular exoskeleton consisting predominantly of a complex polysaccharide network that defines the shape of cells. During growth, this network can be loosened through the action of xyloglucan endotransglycosylases (XETs), glycoside hydrolases that "cut and paste" xyloglucan polysaccharides through a transglycosylation process. We have analyzed cohorts of XETs in different plant species to evaluate the substrate specificities of xyloglucan acceptors by using a set of synthetic oligosaccharides obtained by automated glycan assembly. The ability of XETs to incorporate the oligosaccharides into polysaccharides printed as microarrays and into stem sections of Arabidopsis thaliana, beans, and peas was assessed. We found that single xylose substitutions are sufficient for transfer, and xylosylation of the terminal glucose residue is not required by XETs, independent of plant species. To obtain information on the potential xylosylation pattern of the natural acceptor of XETs, that is, the nonreducing end of xyloglucan, we further tested the activity of xyloglucan xylosyl transferase (XXT) 2 on the synthetic xyloglucan oligosaccharides. These data shed light on inconsistencies between previous studies towards determining the acceptor substrate specificities of XETs and have important implications for further understanding plant cell wall polysaccharide synthesis and remodeling.
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Affiliation(s)
- Colin Ruprecht
- Department of Biomolecular Systems, Max Planck Institute of Colloids and Interfaces, Am Mühlenberg 1, 14476, Potsdam, Germany.,Freie Universität Berlin, Institute of Chemistry and Biochemistry, Arnimallee 22, 14195, Berlin, Germany
| | - Pietro Dallabernardina
- Department of Biomolecular Systems, Max Planck Institute of Colloids and Interfaces, Am Mühlenberg 1, 14476, Potsdam, Germany.,Freie Universität Berlin, Institute of Chemistry and Biochemistry, Arnimallee 22, 14195, Berlin, Germany
| | - Peter J Smith
- Complex Carbohydrate Research Center, University of Georgia, 315 Riverbend Road, Athens, GA, 30602, USA
| | - Breeanna R Urbanowicz
- Complex Carbohydrate Research Center, University of Georgia, 315 Riverbend Road, Athens, GA, 30602, USA
| | - Fabian Pfrengle
- Department of Biomolecular Systems, Max Planck Institute of Colloids and Interfaces, Am Mühlenberg 1, 14476, Potsdam, Germany.,Freie Universität Berlin, Institute of Chemistry and Biochemistry, Arnimallee 22, 14195, Berlin, Germany
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22
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Abstract
The majority of cancer patients receiving chemotherapy will consider taking complementary and alternative medicine (CAM) during their treatment. As biologically-active CAM may detrimentally interfere with chemotherapy treatment, cancer patients require evidence-based information on chemotherapy-CAM integration consequences. This study aimed to assess if the availability of a purpose-designed brochure within a cancer service aided doctors' discussions with their patients on CAM use and helped patients understand the effects of CAM during their chemotherapy treatment. Cancer care doctors consulting in an adult day unit completed a structured post-intervention feedback survey form (n = 17), and cancer patients receiving chemotherapy treatment were provided the brochure and completed the local health service consumer testing feedback form (n = 30). All cancer care doctors perceived a need for the brochure and recommended the brochure to their patients. All doctors thought the brochure made it easier for them to discuss CAM with their patients, and 59 % believed that it saved them time during patient consultations. Ninety percent of cancer patients reported the brochure had enough information to answer their CAM questions, and all patients thought the information was easy to read and understand. An evidence-based CAM-with-chemotherapy patient brochure was perceived to have enabled cancer care doctors to discuss CAM with their patients and to have answered patients' CAM questions.
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Affiliation(s)
- Peter J Smith
- School of Pharmacy, The University of Queensland, Brisbane, Qld, 4072, Australia.
- Sunshine Coast Cancer Care Services, Nambour General Hospital, Nambour, Qld, 4560, Australia.
| | | | - Jeremy E Long
- Sunshine Coast Cancer Care Services, Nambour General Hospital, Nambour, Qld, 4560, Australia
| | - Kathryn J Steadman
- School of Pharmacy, The University of Queensland, Brisbane, Qld, 4072, Australia
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23
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Ekengard E, Bergare I, Hansson J, Doverbratt I, Monari M, Gordhan B, Kana B, De Kock C, Smith PJ, Nordlander E. A pyrazine amide – 4-aminoquinoline hybrid and its rhodium and iridium pentamethylcyclopentadienyl complexes; evaluation of anti-mycobacterial and anti-plasmodial activities. J MEX CHEM SOC 2017. [DOI: 10.29356/jmcs.v61i2.263] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The synthesis and characterization of N-(2-((7-chloroquinolin-4-yl)amino)ethyl)pyrazine-2-carboxamide (<strong>L</strong>), an aminoquinoline – pyrazinamide hybrid, and the complexes (N-(2-((7-chloroquinolin-4-yl)amino)ethyl)pyrazine-2-carboxamide)(cyclopentadienyl) chlorido-rhodium or iridium hexafluorophosphate ([M(<strong>L</strong>)(Cp*)Cl] PF<sub>6</sub>; M = Rh, Ir) and the corresponding chlorido salts ([M(<strong>L</strong>)(Cp*) Cl]Cl; M = Rh, Ir) are described. The ligand and the hexafluorophosphate salts of the metal complexes have been evaluated for anti-plasmodial and anti-mycobacterial activity. The rhodium and the iridium complexes were significantly more active against <em>M. tuberculosis</em> than the free ligand. The crystallographically determined molecular structures of complexes (N-(2-((7-chloroquinolin-4-yl)amino)ethyl)pyrazine-2-carboxamide)(cyclopentadienyl)chlororhodium hexafluoro-phosphate and (N-(2-((7-chloroquinolin-4-yl)amino)ethyl)pyrazine-2-carboxamide)(cyclopentadienyl)chloro-iridium chloride are presented.
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24
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Glassgow AE, Martin MA, Caskey R, Bansa M, Gerges M, Johnson M, Marko M, Perry-Bell K, Risser HJ, Smith PJ, Van Voorhees B. An innovative health-care delivery model for children with medical complexity. J Child Health Care 2017; 21:263-272. [PMID: 29119824 DOI: 10.1177/1367493517712063] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Children with medical complexity (CMC) account for a disproportionate share of pediatric health-care utilization and cost that is largely attributable to long hospitalizations, frequent hospital readmissions, and high use of emergency departments. In response, the Centers for Medicare and Medicaid Services Health Care Innovation Center supports the development and testing of innovative health-care payment and service delivery models. The purpose of this article is to describe the CMS-funded coordinated health care for complex kids (CHECK) program, an innovative system of health-care delivery that provides improved, comprehensive, and well-coordinated services to CMC. The CHECK program uses a combination of high-tech and low-tech interventions to connect patients, stakeholders, and providers. It is anticipated that the investment in additional support services to CMC will result in improved quality of care that leads to a reduction in unnecessary inpatient hospitalizations, readmissions, and emergency department visits and a total cost savings. The CHECK program has the potential to inform future cost-effective health-care models aimed at improving the quality of life and care for CMC and their families.
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Affiliation(s)
| | - Molly A Martin
- 1 Department of Pediatrics, College of Medicine, University of Illinois, Chicago, IL, USA
| | - Rachel Caskey
- 1 Department of Pediatrics, College of Medicine, University of Illinois, Chicago, IL, USA
| | - Melishia Bansa
- 1 Department of Pediatrics, College of Medicine, University of Illinois, Chicago, IL, USA
| | - Michael Gerges
- 1 Department of Pediatrics, College of Medicine, University of Illinois, Chicago, IL, USA
| | - Mary Johnson
- 1 Department of Pediatrics, College of Medicine, University of Illinois, Chicago, IL, USA
| | - Monika Marko
- 1 Department of Pediatrics, College of Medicine, University of Illinois, Chicago, IL, USA
| | - Kenita Perry-Bell
- 1 Department of Pediatrics, College of Medicine, University of Illinois, Chicago, IL, USA
| | - Heather J Risser
- 2 Northwestern University, Feinberg School of Medicine, Chicago, IL, USA
| | - Peter J Smith
- 3 University of Chicago, Department of Medicine, Chicago, IL, USA
| | - Benjamin Van Voorhees
- 1 Department of Pediatrics, College of Medicine, University of Illinois, Chicago, IL, USA
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25
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Wicht KJ, Combrinck JM, Smith PJ, Hunter R, Egan TJ. Identification and Mechanistic Evaluation of Hemozoin-Inhibiting Triarylimidazoles Active against Plasmodium falciparum. ACS Med Chem Lett 2017; 8:201-205. [PMID: 28197312 DOI: 10.1021/acsmedchemlett.6b00416] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2016] [Accepted: 01/24/2017] [Indexed: 11/28/2022] Open
Abstract
In a previous study, target based screening was carried out for inhibitors of β-hematin (synthetic hemozoin) formation, and a series of triarylimidazoles were identified as active against Plasmodium falciparum. Here, we report the subsequent synthesis and testing of derivatives with varying substituents on the three phenyl rings for this series. The results indicated that a 2-hydroxy-1,3-dimethoxy substitution pattern on ring A is required for submicromolar parasite activity. In addition, cell-fractionation studies revealed uncommonly large, dose-dependent increases of P. falciparum intracellular exchangeable (free) heme, correlating with decreased parasite survival for β-hematin inhibiting derivatives.
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Affiliation(s)
- Kathryn J. Wicht
- Department
of Chemistry, University of Cape Town, Rondebosch 7701, South Africa
| | - Jill M. Combrinck
- Division
of Pharmacology, Department of Medicine, Faculty of Health Sciences, University of Cape Town, Observatory 7925, South Africa
| | - Peter J. Smith
- Division
of Pharmacology, Department of Medicine, Faculty of Health Sciences, University of Cape Town, Observatory 7925, South Africa
| | - Roger Hunter
- Department
of Chemistry, University of Cape Town, Rondebosch 7701, South Africa
| | - Timothy J. Egan
- Department
of Chemistry, University of Cape Town, Rondebosch 7701, South Africa
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26
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Espinoza-Moraga M, Singh K, Njoroge M, Kaur G, Okombo J, De Kock C, Smith PJ, Wittlin S, Chibale K. Synthesis and biological characterisation of ester and amide derivatives of fusidic acid as antiplasmodial agents. Bioorg Med Chem Lett 2017; 27:658-661. [DOI: 10.1016/j.bmcl.2016.11.077] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2016] [Revised: 11/23/2016] [Accepted: 11/24/2016] [Indexed: 11/16/2022]
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27
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Cavallo AV, Smith PJ, Morley S, Morsi AW. Non-Vascularized Free Toe Phalanx Transfers in Congenital Hand Deformities – the Great Ormond Street Experience. ACTA ACUST UNITED AC 2017; 28:520-7. [PMID: 14599822 DOI: 10.1016/s0266-7681(03)00084-6] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [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: 10/26/2022]
Abstract
Many options of varying complexity are available for the management of congenital short digits resulting from aphalangia in symbrachydactyly and constriction ring syndrome. We have used non-vascularized free toe phalanx transfers for these children when a vascularized toe transfer has been contraindicated. We describe our technique and experience with 22 children who underwent a total of 64 transfers of the proximal (35) or middle (29) toe phalanges (average 3 per child). The mean age at initial surgery was 15 months, and the mean follow-up was 5 years. Duration of time until epiphyseal closure could not be determined accurately, but total digital elongation averaged 6 mm. Complications of this technique include joint instability, premature epiphyseal closure and, in one patient, infection and graft loss. Donor site deformity was determined according to measured growth deficit and toe function. This technique is a simple option for digital elongation and, if performed in the appropriate age group in short fingered and monodactylous subtypes of symbrachydactyly, has the potential to allow growth and function with minimal donor site deficit.
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Affiliation(s)
- A V Cavallo
- Great Ormond Street Hospital for Children, Great Ormond Street, London, UK
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28
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Stringer T, Seldon R, Liu N, Warner DF, Tam C, Cheng LW, Land KM, Smith PJ, Chibale K, Smith GS. Antimicrobial activity of organometallic isonicotinyl and pyrazinyl ferrocenyl-derived complexes. Dalton Trans 2017; 46:9875-9885. [DOI: 10.1039/c7dt01952a] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Isonicotinyl and pyrazinyl ferrocenyl-derived complexes were evaluatedin vitrofor antimycobacterial and antiparasitic activity.
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29
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Smith PJ, Wang HT, York WS, Peña MJ, Urbanowicz BR. Designer biomass for next-generation biorefineries: leveraging recent insights into xylan structure and biosynthesis. Biotechnol Biofuels 2017; 10:286. [PMID: 29213325 PMCID: PMC5708106 DOI: 10.1186/s13068-017-0973-z] [Citation(s) in RCA: 64] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/31/2017] [Accepted: 11/20/2017] [Indexed: 05/02/2023]
Abstract
Xylans are the most abundant noncellulosic polysaccharides in lignified secondary cell walls of woody dicots and in both primary and secondary cell walls of grasses. These polysaccharides, which comprise 20-35% of terrestrial biomass, present major challenges for the efficient microbial bioconversion of lignocellulosic feedstocks to fuels and other value-added products. Xylans play a significant role in the recalcitrance of biomass to degradation, and their bioconversion requires metabolic pathways that are distinct from those used to metabolize cellulose. In this review, we discuss the key differences in the structural features of xylans across diverse plant species, how these features affect their interactions with cellulose and lignin, and recent developments in understanding their biosynthesis. In particular, we focus on how the combined structural and biosynthetic knowledge can be used as a basis for biomass engineering aimed at developing crops that are better suited as feedstocks for the bioconversion industry.
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Affiliation(s)
- Peter J. Smith
- Complex Carbohydrate Research Center, University of Georgia, 315 Riverbend Road, Athens, GA USA
- BioEnergy Science Center, Oak Ridge National Lab Laboratory, Oak Ridge, TN USA
| | - Hsin-Tzu Wang
- Complex Carbohydrate Research Center, University of Georgia, 315 Riverbend Road, Athens, GA USA
- BioEnergy Science Center, Oak Ridge National Lab Laboratory, Oak Ridge, TN USA
| | - William S. York
- Complex Carbohydrate Research Center, University of Georgia, 315 Riverbend Road, Athens, GA USA
- BioEnergy Science Center, Oak Ridge National Lab Laboratory, Oak Ridge, TN USA
| | - Maria J. Peña
- Complex Carbohydrate Research Center, University of Georgia, 315 Riverbend Road, Athens, GA USA
- BioEnergy Science Center, Oak Ridge National Lab Laboratory, Oak Ridge, TN USA
| | - Breeanna R. Urbanowicz
- Complex Carbohydrate Research Center, University of Georgia, 315 Riverbend Road, Athens, GA USA
- BioEnergy Science Center, Oak Ridge National Lab Laboratory, Oak Ridge, TN USA
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30
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Adams M, de Kock C, Smith PJ, Chibale K, Smith GS. Evaluation of Ferrocenyl-Containing Benzothiazoles as Potential Antiplasmodial Agents. Eur J Inorg Chem 2016. [DOI: 10.1002/ejic.201601000] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Affiliation(s)
- Muneebah Adams
- Department of Chemistry; University of Cape Town; Private Bag, Rondebosch 7701 Cape Town South Africa
| | - Carmen de Kock
- Division of Pharmacology; Department of Medicine; University of Cape Town; Groote Schuur Hospital; K45, OMB, Observatory 7925 Cape Town South Africa
| | - Peter J. Smith
- Division of Pharmacology; Department of Medicine; University of Cape Town; Groote Schuur Hospital; K45, OMB, Observatory 7925 Cape Town South Africa
| | - Kelly Chibale
- Department of Chemistry; University of Cape Town; Private Bag, Rondebosch 7701 Cape Town South Africa
- Institute of Infectious Disease and Molecular Medicine; University of Cape Town; Rondebosch 7701 Cape Town South Africa
- South African Medical Research Council Drug Discovery & Development Research Unit; University of Cape Town; Rondebosch 7701 Cape Town South Africa
| | - Gregory S. Smith
- Department of Chemistry; University of Cape Town; Private Bag, Rondebosch 7701 Cape Town South Africa
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31
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Zuma NH, Smit FJ, de Kock C, Combrinck J, Smith PJ, N'Da DD. Synthesis and biological evaluation of a series of non-hemiacetal ester derivatives of artemisinin. Eur J Med Chem 2016; 122:635-646. [DOI: 10.1016/j.ejmech.2016.07.027] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2016] [Revised: 07/11/2016] [Accepted: 07/12/2016] [Indexed: 01/31/2023]
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32
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Baartzes N, Stringer T, Okombo J, Seldon R, Warner DF, de Kock C, Smith PJ, Smith GS. Mono- and polynuclear ferrocenylthiosemicarbazones: Synthesis, characterisation and antimicrobial evaluation. J Organomet Chem 2016. [DOI: 10.1016/j.jorganchem.2016.06.032] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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33
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Smith PJ, Blumenthal JA. Response to "Does Sleep Play a Role in the Relationship Among Depression, Anxiety, and Mortality in Lung Transplanted Patients?". Am J Transplant 2016; 16:2495. [PMID: 27105775 DOI: 10.1111/ajt.13836] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Affiliation(s)
- P J Smith
- Department of Psychiatry and Behavioral Sciences, Duke University Medical Center, Durham, NC
| | - J A Blumenthal
- Department of Psychiatry and Behavioral Sciences, Duke University Medical Center, Durham, NC
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34
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Smith PJ, Steadman KJ. Antioxidant supplementation and cancer patients receiving curative-intent chemotherapy. Med J Aust 2016; 204:185-185e1. [PMID: 26985844 DOI: 10.5694/mja15.01196] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2015] [Accepted: 12/11/2015] [Indexed: 11/17/2022]
Affiliation(s)
- Peter J Smith
- Sunshine Coast Cancer Care Services, Nambour General Hospital, Nambour, QLD
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35
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Wicht KJ, Combrinck JM, Smith PJ, Hunter R, Egan TJ. Identification and SAR Evaluation of Hemozoin-Inhibiting Benzamides Active against Plasmodium falciparum. J Med Chem 2016; 59:6512-30. [PMID: 27299916 DOI: 10.1021/acs.jmedchem.6b00719] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Quinoline antimalarials target hemozoin formation causing a cytotoxic accumulation of ferriprotoporphyrin IX (Fe(III)PPIX). Well-developed SAR models exist for β-hematin inhibition, parasite activity, and cellular mechanisms for this compound class, but no comparably detailed investigations exist for other hemozoin inhibiting chemotypes. Here, benzamide analogues based on previous HTS hits have been purchased or synthesized. Only derivatives containing an electron deficient aromatic ring and capable of adopting flat conformations, optimal for π-π interactions with Fe(III)PPIX, inhibited β-hematin formation. The two most potent analogues showed nanomolar parasite activity, with little CQ cross-resistance, low cytotoxicity, and high in vitro microsomal stability. Selected analogues inhibited hemozoin formation in Plasmodium falciparum causing high levels of free heme. In contrast to quinolines, introduction of amine side chains did not lead to benzamide accumulation in the parasite. These data reveal complex relationships between heme binding, free heme levels, cellular accumulation, and in vitro activity of potential novel antimalarials.
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Affiliation(s)
- Kathryn J Wicht
- Department of Chemistry, University of Cape Town , Rondebosch 7701, South Africa
| | - Jill M Combrinck
- Department of Chemistry, University of Cape Town , Rondebosch 7701, South Africa.,Division of Pharmacology, Department of Medicine, Faculty of Health Sciences, University of Cape Town , Observatory 7925, South Africa
| | - Peter J Smith
- Division of Pharmacology, Department of Medicine, Faculty of Health Sciences, University of Cape Town , Observatory 7925, South Africa
| | - Roger Hunter
- Department of Chemistry, University of Cape Town , Rondebosch 7701, South Africa
| | - Timothy J Egan
- Department of Chemistry, University of Cape Town , Rondebosch 7701, South Africa
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36
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Ta VD, Carter RM, Esenturk E, Connaughton C, Wasley TJ, Li J, Kay RW, Stringer J, Smith PJ, Shephard JD. Dynamically controlled deposition of colloidal nanoparticle suspension in evaporating drops using laser radiation. Soft Matter 2016; 12:4530-6. [PMID: 27094902 DOI: 10.1039/c6sm00465b] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
Dynamic control of the distribution of polystyrene suspended nanoparticles in evaporating droplets is investigated using a 2.9 μm high power laser. Under laser radiation a droplet is locally heated and fluid flows are induced that overcome the capillary flow, and thus a reversal of the coffee-stain effect is observed. Suspension particles are accumulated in a localised area, one order of magnitude smaller than the original droplet size. By scanning the laser beam over the droplet, particles can be deposited in an arbitrary pattern. This finding raises the possibility for direct laser writing of suspended particles through a liquid layer. Furthermore, a highly uniform coating is possible by manipulating the laser beam diameter and exposure time. The effect is expected to be universally applicable to aqueous solutions independent of solutes (either particles or molecules) and deposited substrates.
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Affiliation(s)
- V D Ta
- Institute of Photonics and Quantum Sciences, Heriot-Watt University, Edinburgh, EH14 4AS, UK.
| | - R M Carter
- Institute of Photonics and Quantum Sciences, Heriot-Watt University, Edinburgh, EH14 4AS, UK.
| | - E Esenturk
- Warwick Mathematics Institute, Zeeman Building, University of Warwick, Coventry CV4 7AL, UK and Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge, CB2 1EW, UK
| | - C Connaughton
- Warwick Mathematics Institute, Zeeman Building, University of Warwick, Coventry CV4 7AL, UK and Centre for Complexity Science, Zeeman Building, University of Warwick, Coventry CV4 7AL, UK
| | - T J Wasley
- Additive Manufacturing Research Group, Loughborough University, Leicestershire, LE11 3TU, UK
| | - J Li
- Additive Manufacturing Research Group, Loughborough University, Leicestershire, LE11 3TU, UK
| | - R W Kay
- Additive Manufacturing Research Group, Loughborough University, Leicestershire, LE11 3TU, UK
| | - J Stringer
- Laboratory of Applied Inkjet Printing, Department of Mechanical Engineering, University of Sheffield, Sheffield, S1 4BJ, UK and Department of Mechanical Engineering, The University of Auckland, Auckland 1142, New Zealand
| | - P J Smith
- Laboratory of Applied Inkjet Printing, Department of Mechanical Engineering, University of Sheffield, Sheffield, S1 4BJ, UK
| | - J D Shephard
- Institute of Photonics and Quantum Sciences, Heriot-Watt University, Edinburgh, EH14 4AS, UK.
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37
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Baartzes N, Stringer T, Chellan P, Combrinck JM, Smith PJ, Hutton AT, Smith GS. Synthesis, characterization, antiplasmodial evaluation and electrochemical studies of water-soluble heterobimetallic ferrocenyl complexes. Inorganica Chim Acta 2016. [DOI: 10.1016/j.ica.2016.02.058] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
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38
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Smith PJ, Clavarino AM, Long JE, Anstey CM, Steadman KJ. Complementary and alternative medicine use by patients receiving curative-intent chemotherapy. Asia Pac J Clin Oncol 2016; 12:265-74. [DOI: 10.1111/ajco.12490] [Citation(s) in RCA: 11] [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] [Accepted: 02/20/2016] [Indexed: 11/28/2022]
Affiliation(s)
- Peter J Smith
- School of Pharmacy; The University of Queensland; Brisbane Australia
- Sunshine Coast Cancer Care Services; Nambour General Hospital; Nambour Australia
| | | | - Jeremy E Long
- Sunshine Coast Cancer Care Services; Nambour General Hospital; Nambour Australia
- School of Medicine; The University of Queensland; Brisbane Australia
| | - Chris M Anstey
- Sunshine Coast Cancer Care Services; Nambour General Hospital; Nambour Australia
- School of Medicine; The University of Queensland; Brisbane Australia
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39
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Smith PJ. Commentary: Old Perceptions Were Too Limited. Intellect Dev Disabil 2016; 54:81-82. [PMID: 27028248 DOI: 10.1352/1934-9556-54.2.81] [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] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Affiliation(s)
- Peter J Smith
- Peter J. Smith, Associate Professor, Pediatrics, University of Chicago, Section of Developmental and Behavioral Pediatrics, Chicago, IL
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40
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Blackie MA, Feng TS, Smith PJ, Chibale K. Synthesis of novel β-lactams and in vitro evaluation against the human malaria parasite Plasmodium falciparum. ARKIVOC 2016. [DOI: 10.3998/ark.5550190.p009.465] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
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41
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Joubert J, Kapp E, Taylor D, Smith PJ, Malan SF. Polycyclic amines as chloroquine resistance modulating agents in Plasmodium falciparum. Bioorg Med Chem Lett 2016; 26:1151-5. [DOI: 10.1016/j.bmcl.2016.01.052] [Citation(s) in RCA: 12] [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] [Received: 11/30/2015] [Revised: 01/15/2016] [Accepted: 01/18/2016] [Indexed: 10/22/2022]
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Kredo T, Mauff K, Workman L, Van der Walt JS, Wiesner L, Smith PJ, Maartens G, Cohen K, Barnes KI. The interaction between artemether-lumefantrine and lopinavir/ritonavir-based antiretroviral therapy in HIV-1 infected patients. BMC Infect Dis 2016; 16:30. [PMID: 26818566 PMCID: PMC4728832 DOI: 10.1186/s12879-016-1345-1] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [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: 08/31/2015] [Accepted: 01/12/2016] [Indexed: 12/16/2022] Open
Abstract
Background Artemether-lumefantrine is currently the most widely recommended treatment of uncomplicated malaria. Lopinavir–based antiretroviral therapy is the commonly recommended second-line HIV treatment. Artemether and lumefantrine are metabolised by cytochrome P450 isoenzyme CYP3A4, which lopinavir/ritonavir inhibits, potentially causing clinically important drug-drug interactions. Methods An adaptive, parallel-design safety and pharmacokinetic study was conducted in HIV-infected (malaria-negative) patients: antiretroviral-naïve and those stable on lopinavir/ritonavir-based antiretrovirals. Both groups received the recommended six-dose artemether-lumefantrine treatment. The primary outcome was day-7 lumefantrine concentrations, as these correlate with antimalarial efficacy. Adverse events were solicited throughout the study, recording the onset, duration, severity, and relationship to artemether-lumefantrine. Results We enrolled 34 patients. Median day-7 lumefantrine concentrations were almost 10-fold higher in the lopinavir than the antiretroviral-naïve group [3170 versus 336 ng/mL; p = 0.0001], with AUC(0-inf) and Cmax increased five-fold [2478 versus 445 μg.h/mL; p = 0.0001], and three-fold [28.2 versus 8.8 μg/mL; p < 0.0001], respectively. Lumefantrine Cmax, and AUC(0-inf) increased significantly with mg/kg dose in the lopinavir, but not the antiretroviral-naïve group. While artemether exposure was similar between groups, Cmax and AUC(0-8h) of its active metabolite dihydroartemisinin were initially two-fold higher in the lopinavir group [p = 0.004 and p = 0.0013, respectively]. However, this difference was no longer apparent after the last artemether-lumefantrine dose. Within 21 days of starting artemether-lumefantrine there were similar numbers of treatment emergent adverse events (42 vs. 35) and adverse reactions (12 vs. 15, p = 0.21) in the lopinavir and antiretroviral-naïve groups, respectively. There were no serious adverse events and no difference in electrocardiographic QTcF- and PR-intervals, at the predicted lumefantrine Tmax. Conclusion Despite substantially higher lumefantrine exposure, intensive monitoring in our relatively small study raised no safety concerns in HIV-infected patients stable on lopinavir-based antiretroviral therapy given the recommended artemether-lumefantrine dosage. Increased day-7 lumefantrine concentrations have been shown previously to reduce the risk of malaria treatment failure, but further evidence in adult patients co-infected with malaria and HIV is needed to assess the artemether-lumefantrine risk : benefit profile in this vulnerable population fully. Our antiretroviral-naïve patients confirmed previous findings that lumefantrine absorption is almost saturated at currently recommended doses, but this dose-limited absorption was overcome in the lopinavir group. Trial registration Clinical Trial Registration number NCT00869700. Registered on clinicaltrials.gov 25 March 2009 Electronic supplementary material The online version of this article (doi:10.1186/s12879-016-1345-1) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- T Kredo
- Division of Clinical Pharmacology, Department of Medicine, University of Cape Town, Cape Town, South Africa. .,Cochrane South Africa, South African Medical Research Council, Cape Town, South Africa.
| | - K Mauff
- Department of Statistical Sciences, University of Cape Town, Cape Town, South Africa.
| | - L Workman
- Division of Clinical Pharmacology, Department of Medicine, University of Cape Town, Cape Town, South Africa.
| | - J S Van der Walt
- Division of Clinical Pharmacology, Department of Medicine, University of Cape Town, Cape Town, South Africa.
| | - L Wiesner
- Division of Clinical Pharmacology, Department of Medicine, University of Cape Town, Cape Town, South Africa.
| | - P J Smith
- Division of Clinical Pharmacology, Department of Medicine, University of Cape Town, Cape Town, South Africa.
| | - G Maartens
- Division of Clinical Pharmacology, Department of Medicine, University of Cape Town, Cape Town, South Africa.
| | - K Cohen
- Division of Clinical Pharmacology, Department of Medicine, University of Cape Town, Cape Town, South Africa.
| | - K I Barnes
- Division of Clinical Pharmacology, Department of Medicine, University of Cape Town, Cape Town, South Africa. .,WorlldWide Antimalarial Resistance Network (WWARN), Oxford, UK.
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Swart M, Evans J, Skelton M, Castel S, Wiesner L, Smith PJ, Dandara C. An Expanded Analysis of Pharmacogenetics Determinants of Efavirenz Response that Includes 3'-UTR Single Nucleotide Polymorphisms among Black South African HIV/AIDS Patients. Front Genet 2016; 6:356. [PMID: 26779253 PMCID: PMC4703773 DOI: 10.3389/fgene.2015.00356] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2015] [Accepted: 12/10/2015] [Indexed: 01/11/2023] Open
Abstract
Introduction: Efavirenz (EFV) is a non-nucleoside reverse transcriptase inhibitor prescribed as part of first-line highly active antiretroviral therapy (HAART) in South Africa. Despite administration of fixed doses of EFV, inter-individual variability in plasma concentrations has been reported. Poor treatment outcomes such as development of adverse drug reactions or treatment failure have been linked to EFV plasma concentrations outside the therapeutic range (1–4 μg/mL) in some studies. The drug metabolizing enzyme (DME), CYP2B6, is primarily responsible for EFV metabolism with minor contributions by CYP1A2, CYP2A6, CYP3A4, CYP3A5, and UGT2B7. DME coding genes are also regulated by microRNAs through targeting the 3′-untranslated region. Expanded analysis of 30 single nucleotide polymorphisms (SNPs), including those in the 3′-UTR, was performed to identify pharmacogenetics determinants of EFV plasma concentrations in addition to CYP2B6 c.516G>T and c.983T>C SNPs. Methods: SNPs in CYP1A2, CYP2B6, UGT2B7, and NR1I2 (PXR) were selected for genotyping among 222 Bantu-speaking South African HIV-infected patients receiving EFV-containing HAART. This study is a continuation of earlier pharmacogenetics studies emphasizing the role of genetic variation in the 3′-UTR of genes which products are either pharmacokinetic or pharmacodynamic targets of EFV. Results: Despite evaluating thirty SNPs, CYP2B6 c.516G>T and c.983T>C SNPs remain the most prominent predictors of EFV plasma concentration. Conclusion: We have shown that CYP2B6 c.516G>T and c.983T>C SNPs are the most important predictors of EFV plasma concentration after taking into account all other SNPs, including genetic variation in the 3′-UTR, and variables affecting EFV metabolism.
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Affiliation(s)
- Marelize Swart
- Division of Human Genetics, Department of Pathology and Institute of Infectious Disease and Molecular Medicine, Faculty of Health Sciences, University of Cape Town Cape Town, South Africa
| | - Jonathan Evans
- Division of Human Genetics, Department of Pathology and Institute of Infectious Disease and Molecular Medicine, Faculty of Health Sciences, University of Cape Town Cape Town, South Africa
| | - Michelle Skelton
- Division of Human Genetics, Department of Pathology and Institute of Infectious Disease and Molecular Medicine, Faculty of Health Sciences, University of Cape Town Cape Town, South Africa
| | - Sandra Castel
- Division of Clinical Pharmacology, Faculty of Health Sciences, University of Cape Town Cape Town, South Africa
| | - Lubbe Wiesner
- Division of Clinical Pharmacology, Faculty of Health Sciences, University of Cape Town Cape Town, South Africa
| | - Peter J Smith
- Division of Clinical Pharmacology, Faculty of Health Sciences, University of Cape Town Cape Town, South Africa
| | - Collet Dandara
- Division of Human Genetics, Department of Pathology and Institute of Infectious Disease and Molecular Medicine, Faculty of Health Sciences, University of Cape Town Cape Town, South Africa
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Kuter D, Mohunlal R, Fitzroy SM, Asher C, Smith PJ, Egan TJ, de Villiers KA. Insights into the initial stages of lipid-mediated haemozoin nucleation. CrystEngComm 2016. [DOI: 10.1039/c6ce00866f] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Lipid-mediated haemozoin nucleation, as probed by molecular dynamics, proceeds via aggregation of ferrihaem π–π dimers at a lipid–aqueous interface.
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Affiliation(s)
- David Kuter
- Department of Chemistry and Polymer Science
- Stellenbosch University
- Matieland 7602, South Africa
| | - Roxanne Mohunlal
- Department of Chemistry
- University of Cape Town
- Rondebosch 7701, South Africa
| | - Sharné-Maré Fitzroy
- Department of Chemistry and Polymer Science
- Stellenbosch University
- Matieland 7602, South Africa
| | - Constance Asher
- Department of Chemistry
- University of Cape Town
- Rondebosch 7701, South Africa
| | - Peter J. Smith
- Division of Pharmacology
- Department of Medicine
- University of Cape Town Medical School
- Observatory 7925, South Africa
| | - Timothy J. Egan
- Department of Chemistry
- University of Cape Town
- Rondebosch 7701, South Africa
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45
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Ekengard E, Kumar K, Fogeron T, de Kock C, Smith PJ, Haukka M, Monari M, Nordlander E. Pentamethylcyclopentadienyl-rhodium and iridium complexes containing (N^N and N^O) bound chloroquine analogue ligands: synthesis, characterization and antimalarial properties. Dalton Trans 2016; 45:3905-17. [DOI: 10.1039/c5dt03739e] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Rhodium and iridium cyclopentadienyl complexes have been examined for anti-malarial activity. Three rhodium complexes are especially active.
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Affiliation(s)
- Erik Ekengard
- Inorganic Chemistry Research Group
- Chemical Physics
- Center for Chemistry and Chemical Engineering
- Lund University
- SE-221 00 Lund
| | - Kamlesh Kumar
- Inorganic Chemistry Research Group
- Chemical Physics
- Center for Chemistry and Chemical Engineering
- Lund University
- SE-221 00 Lund
| | - Thibault Fogeron
- Inorganic Chemistry Research Group
- Chemical Physics
- Center for Chemistry and Chemical Engineering
- Lund University
- SE-221 00 Lund
| | - Carmen de Kock
- Division of Pharmacology
- Department of Medicine
- University of Cape Town Medical School
- Observatory 7925
- South Africa
| | - Peter J. Smith
- Division of Pharmacology
- Department of Medicine
- University of Cape Town Medical School
- Observatory 7925
- South Africa
| | - Matti Haukka
- Department of Chemistry
- University of Jyväskylä
- Jyväskylä
- Finland
| | - Magda Monari
- Dipartimento di Chimica “G. Ciamician”
- Alma Mater Studiorum Università di Bologna
- 40126 Bologna
- Italy
| | - Ebbe Nordlander
- Inorganic Chemistry Research Group
- Chemical Physics
- Center for Chemistry and Chemical Engineering
- Lund University
- SE-221 00 Lund
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Adams M, Barnard L, de Kock C, Smith PJ, Wiesner L, Chibale K, Smith GS. Cyclopalladated organosilane–tethered thiosemicarbazones: novel strategies for improving antiplasmodial activity. Dalton Trans 2016; 45:5514-20. [DOI: 10.1039/c5dt04918k] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Ferrocenyl- and aryl-derived cyclopalladated organosilane thiosemicarbazone complexes were synthesised via C–H bond activation and evaluated for antiplasmodial activity.
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Affiliation(s)
- Muneebah Adams
- Department of Chemistry
- University of Cape Town
- Rondebosch 7701
- South Africa
| | - Linley Barnard
- Department of Chemistry
- University of Cape Town
- Rondebosch 7701
- South Africa
| | - Carmen de Kock
- Division of Pharmacology
- Department of Medicine
- University of Cape Town
- K45
- OMB
| | - Peter J. Smith
- Division of Pharmacology
- Department of Medicine
- University of Cape Town
- K45
- OMB
| | - Lubbe Wiesner
- Division of Pharmacology
- Department of Medicine
- University of Cape Town
- K45
- OMB
| | - Kelly Chibale
- Department of Chemistry
- University of Cape Town
- Rondebosch 7701
- South Africa
- Institute of Infectious Disease and Molecular Medicine
| | - Gregory S. Smith
- Department of Chemistry
- University of Cape Town
- Rondebosch 7701
- South Africa
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47
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Adams M, Stringer T, de Kock C, Smith PJ, Land KM, Liu N, Tam C, Cheng LW, Njoroge M, Chibale K, Smith GS. Bioisosteric ferrocenyl-containing quinolines with antiplasmodial and antitrichomonal properties. Dalton Trans 2016; 45:19086-19095. [DOI: 10.1039/c6dt03175g] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Bioisosteric (C, Si) ferrocenyl-containing quinolines and ferrocenylamines were prepared and evaluated as antiplasmodial and antitrichomonal agents.
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48
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Stringer T, De Kock C, Guzgay H, Okombo J, Liu J, Kanetake S, Kim J, Tam C, Cheng LW, Smith PJ, Hendricks DT, Land KM, Egan TJ, Smith GS. Mono- and multimeric ferrocene congeners of quinoline-based polyamines as potential antiparasitics. Dalton Trans 2016; 45:13415-26. [DOI: 10.1039/c6dt02685k] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A series of mono- and multimeric polyamine-containing ferrocenyl complexes bearing a quinoline motif were prepared.
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49
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van Schalkwyk DA, Nash MN, Shafik SH, Summers RL, Lehane AM, Smith PJ, Martin RE. Verapamil-Sensitive Transport of Quinacrine and Methylene Blue via the Plasmodium falciparum Chloroquine Resistance Transporter Reduces the Parasite's Susceptibility to these Tricyclic Drugs. J Infect Dis 2015; 213:800-10. [PMID: 26503982 DOI: 10.1093/infdis/jiv509] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [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: 09/04/2015] [Accepted: 10/15/2015] [Indexed: 12/16/2022] Open
Abstract
BACKGROUND It is becoming increasingly apparent that certain mutations in the Plasmodium falciparum chloroquine resistance transporter (PfCRT) alter the parasite's susceptibility to diverse compounds. Here we investigated the interaction of PfCRT with 3 tricyclic compounds that have been used to treat malaria (quinacrine [QC] and methylene blue [MB]) or to study P. falciparum (acridine orange [AO]). METHODS We measured the antiplasmodial activities of QC, MB, and AO against chloroquine-resistant and chloroquine-sensitive P. falciparum and determined whether QC and AO affect the accumulation and activity of chloroquine in these parasites. We also assessed the ability of mutant (PfCRT(Dd2)) and wild-type (PfCRT(D10)) variants of the protein to transport QC, MB, and AO when expressed at the surface of Xenopus laevis oocytes. RESULTS Chloroquine resistance-conferring isoforms of PfCRT reduced the susceptibility of the parasite to QC, MB, and AO. In chloroquine-resistant (but not chloroquine-sensitive) parasites, AO and QC increased the parasite's accumulation of, and susceptibility to, chloroquine. All 3 compounds were shown to bind to PfCRT(Dd2), and the transport of QC and MB via this protein was saturable and inhibited by the chloroquine resistance-reverser verapamil. CONCLUSIONS Our findings reveal that the PfCRT(Dd2)-mediated transport of tricyclic antimalarials reduces the parasite's susceptibility to these drugs.
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Affiliation(s)
| | - Megan N Nash
- Research School of Biology, Australian National University, Canberra, Australia
| | - Sarah H Shafik
- Research School of Biology, Australian National University, Canberra, Australia
| | - Robert L Summers
- Research School of Biology, Australian National University, Canberra, Australia
| | - Adele M Lehane
- Research School of Biology, Australian National University, Canberra, Australia
| | - Peter J Smith
- Division of Pharmacology, Department of Medicine, University of Cape Town, Rondebosch, South Africa
| | - Rowena E Martin
- Research School of Biology, Australian National University, Canberra, Australia
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50
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Jacobs L, de Kock C, de Villiers KA, Smith PJ, Smith VJ, van Otterlo WAL, Blackie MAL. Design, Synthesis, and Evaluation of Novel Ferroquine and Phenylequine Analogues as Potential Antiplasmodial Agents. ChemMedChem 2015; 10:2099-110. [PMID: 26447782 DOI: 10.1002/cmdc.201500349] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2015] [Indexed: 11/11/2022]
Abstract
7-Chloroquinoline-based antimalarial drugs are effective in the inhibition of hemozoin formation in the food vacuole of the Plasmodium parasite, the causative agent of malaria. We synthesized five series of ferroquine (FQ) and phenylequine (PQ) derivatives, which display good in vitro efficacy toward both the chloroquine-sensitive (CQS) NF54 (IC50 : 4.2 nm) and chloroquine-resistant (CQR) Dd2 (IC50 : 33.7 nm) strains of P. falciparum. Several compounds were found to have good inhibitory activity against β-hematin formation in an NP-40 detergent assay, with IC50 values ranging between 10.4 and 19.2 μm.
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Affiliation(s)
- Leon Jacobs
- Department of Chemistry and Polymer Science, Stellenbosch University, Private Bag X1, Matieland, 7602, South Africa
| | - Carmen de Kock
- Department of Pharmacology, University of Cape Town, Private Bag X2, Rondebosch, Cape Town, 7700, South Africa
| | - Katherine A de Villiers
- Department of Chemistry and Polymer Science, Stellenbosch University, Private Bag X1, Matieland, 7602, South Africa
| | - Peter J Smith
- Department of Pharmacology, University of Cape Town, Private Bag X2, Rondebosch, Cape Town, 7700, South Africa
| | - Vincent J Smith
- Department of Chemistry and Polymer Science, Stellenbosch University, Private Bag X1, Matieland, 7602, South Africa
| | - Willem A L van Otterlo
- Department of Chemistry and Polymer Science, Stellenbosch University, Private Bag X1, Matieland, 7602, South Africa
| | - Margaret A L Blackie
- Department of Chemistry and Polymer Science, Stellenbosch University, Private Bag X1, Matieland, 7602, South Africa.
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