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Clark A, Ferkh A, Vandenberg J, Elhindi J, Thomas L. Altered left atrial metrics in patients with cryptogenic stroke: A systematic review and meta-analysis. Eur J Clin Invest 2024:e14175. [PMID: 38308431 DOI: 10.1111/eci.14175] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/29/2023] [Revised: 01/14/2024] [Accepted: 01/22/2024] [Indexed: 02/04/2024]
Abstract
BACKGROUND There is no defined cause for cryptogenic stroke/embolic stroke of undetermined source (CS-ESUS). As atrial fibrillation (AF) develops in a significant proportion of these patients, it has been suggested that left atrial (LA) myopathy may predispose to CS-ESUS. We investigated alterations in echocardiographic measures of LA size and function in patients with CS-ESUS. METHODS A systematic literature review and meta-analysis was performed. PubMed, EMBASE, Cochrane Library, Web of Science and SCOPUS were searched for articles published between 1 January 1990 and 10 February 2023. All observational studies of adult CS-ESUS patients with LA volume or function measurements performed by transthoracic echocardiogram were included. Individual random effects meta-analyses were performed on LA measurements in the CS-ESUS patients using subgroup analysis of comparator groups. RESULTS We included 29 articles with 3927 CS-ESUS patients. Analysis of weighted mean differences showed CS-ESUS patients had altered LA structure and function parameters, with a larger maximum indexed LA volume, reduced LA emptying fraction and/or LA reservoir strain, compared to healthy controls and noncardioembolic stroke patients. Conversely, CS-ESUS patients had a smaller left atrium with better function, compared to cardioembolic stroke patients and CS-ESUS patients who subsequently developed atrial fibrillation. CONCLUSIONS LA volume and function are altered in CS-ESUS patients compared to healthy controls and other stroke aetiologies. An underlying atrial myopathy in a subset of CS-ESUS patients may be involved in both thrombogenesis and dysrhythmia (specifically AF). While LA functional assessment is not currently recommended following stroke, it may offer an opportunity for recurrent stroke risk stratification.
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Affiliation(s)
- Amy Clark
- Department of Cardiology, Westmead Hospital, Westmead, New South Wales, Australia
- Westmead Clinical School, University of Sydney, Camperdown, Sydney, New South Wales, Australia
| | - Aaisha Ferkh
- Department of Cardiology, Westmead Hospital, Westmead, New South Wales, Australia
- Westmead Clinical School, University of Sydney, Camperdown, Sydney, New South Wales, Australia
| | - Jamie Vandenberg
- Mark Cowley Lidwill Research Program in Cardiac Electrophysiology, Victor Chang Cardiac Research Institute, Darlinghurst, New South Wales, Australia
- School of Clinical Medicine, UNSW Sydney, Darlinghurst, New South Wales, Australia
| | - James Elhindi
- WSLHD Research and Education Network, Westmead Hospital, Westmead, New South Wales, Australia
| | - Liza Thomas
- Department of Cardiology, Westmead Hospital, Westmead, New South Wales, Australia
- Westmead Clinical School, University of Sydney, Camperdown, Sydney, New South Wales, Australia
- South West Clinical School, University of New South Wales, Kensington, New South Wales, Australia
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Lau C, Flood E, Hunter M, Corbett K, Ng C, Bouwer J, Stewart A, Perozo E, Allen TW, Vandenberg J. Structural basis of rapid inactivation of HERG potassium channels. Biophys J 2023; 122:446a. [PMID: 36784292 DOI: 10.1016/j.bpj.2022.11.2409] [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: 02/12/2023] Open
Affiliation(s)
- Carus Lau
- Victor Chang Cardiac Research Institute, Sydney, Australia; St Vincent's Clinical School, University of New South Wales, Sydney, Australia
| | - Emelie Flood
- Royal Melbourne Institute of Technology, Melbourne, Australia
| | - Mark Hunter
- Victor Chang Cardiac Research Institute, Sydney, Australia; St Vincent's Clinical School, University of New South Wales, Sydney, Australia
| | - Karen Corbett
- Royal Melbourne Institute of Technology, Melbourne, Australia
| | - Chai Ng
- Victor Chang Cardiac Research Institute, Sydney, Australia; St Vincent's Clinical School, University of New South Wales, Sydney, Australia
| | | | - Alastair Stewart
- Victor Chang Cardiac Research Institute, Sydney, Australia; St Vincent's Clinical School, University of New South Wales, Sydney, Australia
| | | | - Toby W Allen
- Royal Melbourne Institute of Technology, Melbourne, Australia
| | - Jamie Vandenberg
- Victor Chang Cardiac Research Institute, Sydney, Australia; St Vincent's Clinical School, University of New South Wales, Sydney, Australia
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Ganesan AN, Vanoye CG, Alam F, Waddell-Smith KE, McGavigan AD, Correnti G, Haan E, Brown A, Vandenberg J, George AL. Long QT Syndrome Type 1 in an Australian Indigenous Patient. Circ Genom Precis Med 2020; 13:e002813. [PMID: 32004091 DOI: 10.1161/circgen.119.002813] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Affiliation(s)
- Anand N Ganesan
- College of Medicine and Public Health, Flinders University, Adelaide, Australia (A.N.G., K.E.W.-S., A.D.M.).,South Australian Health and Medical Research Institute, Adelaide, Australia (A.N.G., A.B.).,Department of Cardiovascular Medicine, Flinders Medical Centre, Adelaide, Australia (A.N.G., K.E.W.-S., A.D.M.)
| | - Carlos G Vanoye
- Department of Pharmacology, Northwestern University Feinberg School of Medicine, Chicago, IL (C.G.V., A.L.G.)
| | | | - Kathryn E Waddell-Smith
- College of Medicine and Public Health, Flinders University, Adelaide, Australia (A.N.G., K.E.W.-S., A.D.M.).,Department of Cardiovascular Medicine, Flinders Medical Centre, Adelaide, Australia (A.N.G., K.E.W.-S., A.D.M.)
| | - Andrew D McGavigan
- College of Medicine and Public Health, Flinders University, Adelaide, Australia (A.N.G., K.E.W.-S., A.D.M.).,Department of Cardiovascular Medicine, Flinders Medical Centre, Adelaide, Australia (A.N.G., K.E.W.-S., A.D.M.)
| | - Gemma Correnti
- Adult Genetics Unit, Royal Adelaide Hospital, Australia (G.C., E.H.)
| | - Eric Haan
- Adult Genetics Unit, Royal Adelaide Hospital, Australia (G.C., E.H.).,Faculty of Health and Medical Sciences, University of Adelaide, South Australia (E.H., A.B.)
| | - Alex Brown
- South Australian Health and Medical Research Institute, Adelaide, Australia (A.N.G., A.B.).,Faculty of Health and Medical Sciences, University of Adelaide, South Australia (E.H., A.B.)
| | - Jamie Vandenberg
- Victor Chang Cardiac Research Institute, Sydney, Australia (J.V.)
| | - Alfred L George
- Department of Pharmacology, Northwestern University Feinberg School of Medicine, Chicago, IL (C.G.V., A.L.G.)
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Li Z, Mirams GR, Yoshinaga T, Ridder BJ, Han X, Chen JE, Stockbridge NL, Wisialowski TA, Damiano B, Severi S, Morissette P, Kowey PR, Holbrook M, Smith G, Rasmusson RL, Liu M, Song Z, Qu Z, Leishman DJ, Steidl‐Nichols J, Rodriguez B, Bueno‐Orovio A, Zhou X, Passini E, Edwards AG, Morotti S, Ni H, Grandi E, Clancy CE, Vandenberg J, Hill A, Nakamura M, Singer T, Polonchuk L, Greiter‐Wilke A, Wang K, Nave S, Fullerton A, Sobie EA, Paci M, Musuamba Tshinanu F, Strauss DG. General Principles for the Validation of Proarrhythmia Risk Prediction Models: An Extension of the CiPA In Silico Strategy. Clin Pharmacol Ther 2020; 107:102-111. [PMID: 31709525 PMCID: PMC6977398 DOI: 10.1002/cpt.1647] [Citation(s) in RCA: 55] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2019] [Accepted: 09/06/2019] [Indexed: 12/27/2022]
Abstract
This white paper presents principles for validating proarrhythmia risk prediction models for regulatory use as discussed at the In Silico Breakout Session of a Cardiac Safety Research Consortium/Health and Environmental Sciences Institute/US Food and Drug Administration-sponsored Think Tank Meeting on May 22, 2018. The meeting was convened to evaluate the progress in the development of a new cardiac safety paradigm, the Comprehensive in Vitro Proarrhythmia Assay (CiPA). The opinions regarding these principles reflect the collective views of those who participated in the discussion of this topic both at and after the breakout session. Although primarily discussed in the context of in silico models, these principles describe the interface between experimental input and model-based interpretation and are intended to be general enough to be applied to other types of nonclinical models for proarrhythmia assessment. This document was developed with the intention of providing a foundation for more consistency and harmonization in developing and validating different models for proarrhythmia risk prediction using the example of the CiPA paradigm.
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Tardo D, Peck M, Hill A, Vandenberg J. T Wave Morphology Biomarkers in Congenital and Acquired Long QT Syndrome. Heart Lung Circ 2019. [DOI: 10.1016/j.hlc.2019.06.223] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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Lee W, Mangala M, Windley M, Perry M, Vandenberg J, Hill A. Novel Pre–Clinical Risk Prediction of Acquired Long QT Syndrome. Heart Lung Circ 2018. [DOI: 10.1016/j.hlc.2018.06.309] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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Ng T, Vandenberg J, Perry M. Pharmacological Activation of hERG Potassium Channels in Congenital Long QT Syndrome 2: Activator Compound ICA-105574 and its Effects on Mutant hERG Potassium Channels in Long QT Syndrome 2. Heart Lung Circ 2018. [DOI: 10.1016/j.hlc.2018.06.039] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Windley M, Mann S, Vandenberg J, Hill A. Temperature Effects on Kinetics of hERG Drug Block: Implications for In Silico Proarrhythmic Risk Prediction. J Pharmacol Toxicol Methods 2017. [DOI: 10.1016/j.vascn.2017.09.116] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Fonoudi H, Ansari H, Abbasalizadeh S, Larijani MR, Kiani S, Hashemizadeh S, Zarchi AS, Bosman A, Blue GM, Pahlavan S, Perry M, Orr Y, Mayorchak Y, Vandenberg J, Talkhabi M, Winlaw DS, Harvey RP, Aghdami N, Baharvand H. A Universal and Robust Integrated Platform for the Scalable Production of Human Cardiomyocytes From Pluripotent Stem Cells. Stem Cells Transl Med 2015; 4:1482-94. [PMID: 26511653 DOI: 10.5966/sctm.2014-0275] [Citation(s) in RCA: 88] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2014] [Accepted: 07/08/2015] [Indexed: 12/15/2022] Open
Abstract
UNLABELLED Recent advances in the generation of cardiomyocytes (CMs) from human pluripotent stem cells (hPSCs), in conjunction with the promising outcomes from preclinical and clinical studies, have raised new hopes for cardiac cell therapy. We report the development of a scalable, robust, and integrated differentiation platform for large-scale production of hPSC-CM aggregates in a stirred suspension bioreactor as a single-unit operation. Precise modulation of the differentiation process by small molecule activation of WNT signaling, followed by inactivation of transforming growth factor-β and WNT signaling and activation of sonic hedgehog signaling in hPSCs as size-controlled aggregates led to the generation of approximately 100% beating CM spheroids containing virtually pure (∼90%) CMs in 10 days. Moreover, the developed differentiation strategy was universal, as demonstrated by testing multiple hPSC lines (5 human embryonic stem cell and 4 human inducible PSC lines) without cell sorting or selection. The produced hPSC-CMs successfully expressed canonical lineage-specific markers and showed high functionality, as demonstrated by microelectrode array and electrophysiology tests. This robust and universal platform could become a valuable tool for the mass production of functional hPSC-CMs as a prerequisite for realizing their promising potential for therapeutic and industrial applications, including drug discovery and toxicity assays. SIGNIFICANCE Recent advances in the generation of cardiomyocytes (CMs) from human pluripotent stem cells (hPSCs) and the development of novel cell therapy strategies using hPSC-CMs (e.g., cardiac patches) in conjunction with promising preclinical and clinical studies, have raised new hopes for patients with end-stage cardiovascular disease, which remains the leading cause of morbidity and mortality globally. In this study, a simplified, scalable, robust, and integrated differentiation platform was developed to generate clinical grade hPSC-CMs as cell aggregates under chemically defined culture conditions. This approach resulted in approximately 100% beating CM spheroids with virtually pure (∼90%) functional cardiomyocytes in 10 days from multiple hPSC lines. This universal and robust bioprocessing platform can provide sufficient numbers of hPSC-CMs for companies developing regenerative medicine technologies to rescue, replace, and help repair damaged heart tissues and for pharmaceutical companies developing advanced biologics and drugs for regeneration of lost heart tissue using high-throughput technologies. It is believed that this technology can expedite clinical progress in these areas to achieve a meaningful impact on improving clinical outcomes, cost of care, and quality of life for those patients disabled and experiencing heart disease.
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Affiliation(s)
- Hananeh Fonoudi
- Department of Stem Cells and Developmental Biology, Cell Science Research Center, Royan Institute for Stem Cell Biology and Technology, Academic Center for Education, Culture and Research, Tehran, Iran Developmental and Stem Cell Biology Division, Victor Chang Cardiac Research Institute, Darlinghurst, Sydney, New South Wales, Australia St. Vincent's Clinical School, Faculty of Medicine, University of New South Wales, Kensington, New South Wales, Australia
| | - Hassan Ansari
- Department of Stem Cells and Developmental Biology, Cell Science Research Center, Royan Institute for Stem Cell Biology and Technology, Academic Center for Education, Culture and Research, Tehran, Iran
| | - Saeed Abbasalizadeh
- Department of Stem Cells and Developmental Biology, Cell Science Research Center, Royan Institute for Stem Cell Biology and Technology, Academic Center for Education, Culture and Research, Tehran, Iran
| | - Mehran Rezaei Larijani
- Department of Stem Cells and Developmental Biology, Cell Science Research Center, Royan Institute for Stem Cell Biology and Technology, Academic Center for Education, Culture and Research, Tehran, Iran
| | - Sahar Kiani
- Department of Stem Cells and Developmental Biology, Cell Science Research Center, Royan Institute for Stem Cell Biology and Technology, Academic Center for Education, Culture and Research, Tehran, Iran
| | - Shiva Hashemizadeh
- Department of Stem Cells and Developmental Biology, Cell Science Research Center, Royan Institute for Stem Cell Biology and Technology, Academic Center for Education, Culture and Research, Tehran, Iran
| | - Ali Sharifi Zarchi
- Department of Stem Cells and Developmental Biology, Cell Science Research Center, Royan Institute for Stem Cell Biology and Technology, Academic Center for Education, Culture and Research, Tehran, Iran
| | - Alexis Bosman
- Developmental and Stem Cell Biology Division, Victor Chang Cardiac Research Institute, Darlinghurst, Sydney, New South Wales, Australia St. Vincent's Clinical School, Faculty of Medicine, University of New South Wales, Kensington, New South Wales, Australia
| | - Gillian M Blue
- Kids Heart Research, The Children's Hospital at Westmead, Sydney, New South Wales, Australia The Heart Centre for Children, The Children's Hospital at Westmead, Sydney, New South Wales, Australia Sydney Medical School, University of Sydney, Sydney, New South Wales, Australia
| | - Sara Pahlavan
- Department of Stem Cells and Developmental Biology, Cell Science Research Center, Royan Institute for Stem Cell Biology and Technology, Academic Center for Education, Culture and Research, Tehran, Iran
| | - Matthew Perry
- St. Vincent's Clinical School, Faculty of Medicine, University of New South Wales, Kensington, New South Wales, Australia Molecular Cardiology and Biophysics Division, Victor Chang Cardiac Research Institute, Darlinghurst, Sydney, New South Wales, Australia
| | - Yishay Orr
- Kids Heart Research, The Children's Hospital at Westmead, Sydney, New South Wales, Australia The Heart Centre for Children, The Children's Hospital at Westmead, Sydney, New South Wales, Australia
| | - Yaroslav Mayorchak
- The Heart Centre for Children, The Children's Hospital at Westmead, Sydney, New South Wales, Australia
| | - Jamie Vandenberg
- St. Vincent's Clinical School, Faculty of Medicine, University of New South Wales, Kensington, New South Wales, Australia Molecular Cardiology and Biophysics Division, Victor Chang Cardiac Research Institute, Darlinghurst, Sydney, New South Wales, Australia
| | - Mahmood Talkhabi
- Department of Stem Cells and Developmental Biology, Cell Science Research Center, Royan Institute for Stem Cell Biology and Technology, Academic Center for Education, Culture and Research, Tehran, Iran
| | - David S Winlaw
- Kids Heart Research, The Children's Hospital at Westmead, Sydney, New South Wales, Australia The Heart Centre for Children, The Children's Hospital at Westmead, Sydney, New South Wales, Australia Sydney Medical School, University of Sydney, Sydney, New South Wales, Australia
| | - Richard P Harvey
- Developmental and Stem Cell Biology Division, Victor Chang Cardiac Research Institute, Darlinghurst, Sydney, New South Wales, Australia St. Vincent's Clinical School, Faculty of Medicine, University of New South Wales, Kensington, New South Wales, Australia School of Biotechnology and Biomolecular Sciences, University of New South Wales, Kensington, New South Wales, Australia
| | - Nasser Aghdami
- Department of Stem Cells and Developmental Biology, Cell Science Research Center, Royan Institute for Stem Cell Biology and Technology, Academic Center for Education, Culture and Research, Tehran, Iran
| | - Hossein Baharvand
- Department of Stem Cells and Developmental Biology, Cell Science Research Center, Royan Institute for Stem Cell Biology and Technology, Academic Center for Education, Culture and Research, Tehran, Iran Department of Developmental Biology, University of Science and Culture, Academic Center for Education, Culture and Research, Tehran, Iran
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Martinac B, Vandenberg J. 'Shooting gallery' for membrane proteins provides new insights into complexities of their function and structural dynamics. J Physiol 2015; 593:353-4. [PMID: 25630256 DOI: 10.1113/jphysiol.2014.286559] [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] [Indexed: 11/08/2022] Open
Affiliation(s)
- Boris Martinac
- Victor Chang Cardiac Research Institute, Level 6, 405 Liverpool Street, Darlinghurst, NSW, 2010, Australia; St Vincent's Clinical School, University of New South Wales, Victoria Street, Darlinghurst, NSW, 2010, Australia
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DeWoskin R, Sweeney L, Teeguarden J, Sams R, Vandenberg J. Comparison of PBTK model and biomarker based estimates of the internal dosimetry of acrylamide. Food Chem Toxicol 2013; 58:506-21. [DOI: 10.1016/j.fct.2013.05.008] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2012] [Revised: 05/06/2013] [Accepted: 05/07/2013] [Indexed: 10/26/2022]
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Mann S, Sadrieh A, Subbiah R, Domanski L, Taylor J, Vandenberg J, Hill A. Epistatic Interactions of Ion Channels Underlie Variability in Cardiac Electrical Activity. In-silico Analysis of the Electrocardiogram. Heart Lung Circ 2013. [DOI: 10.1016/j.hlc.2013.05.226] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Ke Y, Hunter M, Ng CA, Vandenberg J. Domain Misfolding and Destabilisation of Domain–Domain Interactions Both Contribute to Defective Trafficking of hERG EAG Domain Mutant Channels. Heart Lung Circ 2012. [DOI: 10.1016/j.hlc.2012.08.025] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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Migiro LN, Maniania NK, Chabi-Olaye A, Vandenberg J. Pathogenicity of entomopathogenic fungi Metarhizium anisopliae and Beauveria bassiana (Hypocreales: Clavicipitaceae) isolates to the adult pea leafminer (Diptera: Agromyzidae) and prospects of an autoinoculation device for infection in the field. Environ Entomol 2010; 39:468-75. [PMID: 20388276 DOI: 10.1603/en09359] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Seventeen isolates of Metarhizium anisopliae (Metschnikoff) Sorokin and three isolates of Beauveria bassiana (Balsamo) Vuillemin (Hypocreales: Clavicipitaceae) were evaluated for their pathogenicity to the adult pea leafminer, Liriomyza huidobrensis (Blanchard) (Diptera: Agromyzidae), in the laboratory. Flies were contaminated with dry conidia through a velvet material wrapped around the inner side of a cylindrical plastic tube. All the isolates were pathogenic to the pea leafminer, causing mortality between 40 and 100% at 5 d after exposure. The lethal time for 50% mortality (LT(50)) ranged from 2.6 to 5.4 d, whereas the LT(90) values varied between 3.2 and 9.1 d depending on the isolate. An autoinoculation device was evaluated in cage field experiments using only one of the virulent isolates, M. anisopliae ICIPE 20. The device was loaded with 2-3 g of dry conidia. Mortality of up to 100% was observed in flies captured from fungus-treated cages held under laboratory conditions. The average number of spores picked up by a single fly visiting the device increased with days after inoculation. One day after the inoculation, adults picked up an average of 4.1 +/- 0.7 x 10(5) conidia and 39.6 +/- 4.0 x 10(5) conidia 5 d after inoculation. Depending on the sampling date, the LT(50) varied between 1.8 and 3.4 d. Results indicate that some isolates of B. bassiana and M. anisopliae are highly pathogenic to L. huidobrensis, suggesting a potential for their use in the control of this pest. They also suggest the possibility of L. huidobrensis suppression with fungi using an autoinoculation device.
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Affiliation(s)
- L N Migiro
- International Centre of Insect Physiology and Ecology, PO Box 30772-00100, Nairobi, Kenya, South Africa.
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Singarayar S, Bursill J, Wyse K, Bauskin A, Wu W, Vandenberg J, Breit S, Campbell T. Extracellular acidosis modulates drug block of Kv4.3 currents by flecainide and quinidine. J Cardiovasc Electrophysiol 2003; 14:641-50. [PMID: 12875427 DOI: 10.1046/j.1540-8167.2003.03026.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
INTRODUCTION As a molecular model of the effect of ischemia on drug block of the transient outward potassium current, the effect of acidosis on the blocking properties of flecainide and quinidine on Kv4.3 currents was studied. METHODS AND RESULTS Kv4.3 channels were stably expressed in Chinese hamster ovary cells. Whole-cell, voltage clamp techniques were used to measure the effect of flecainide and quinidine on Kv4.3 currents in solutions of pH 7.4 and 6.0. Extracellular acidosis attenuated flecainide block of Kv4.3 currents, with the IC50 for flecainide (based on current-time integrals) increasing from 7.8 +/- 1.1 microM at pH 7.4 to 125.1 +/- 1.1 microM at pH 6.0. Similar effects were observed for quinidine (IC50 5.2 +/- 1.1 microM at pH 7.4 and 22.1 +/- 1.3 microM at pH 6.0). Following block by either drug, Kv4.3 channels showed a hyperpolarizing shift in the voltage sensitivity of inactivation and a slowing in the time to recover from inactivation/block that was unaffected by acidosis. In contrast, acidosis attenuated the effects on the time course of inactivation and the degree of tonic- and frequency-dependent block for both drugs. CONCLUSION Extracellular acidosis significantly decreases the potency of blockade of Kv4.3 by both flecainide and quinidine. This change in potency may be due to allosteric changes in the channel, changes in the proportion of uncharged drug, and/or changes in the kinetics of drug binding or unbinding. These findings are in contrast to the effects of extracellular acidosis on block of the fast sodium channel by these agents and provide a molecular mechanism for divergent modulation of drug block potentially leading to ischemia-associated proarrhythmia.
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Affiliation(s)
- Suresh Singarayar
- Department of Medicine, The University of New South Wales, Victor Chang Cardiac Research Institute, Sydney Australia
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Brauer M, Hrubá F, Mihalíková E, Fabiánová E, Miskovic P, Plziková A, Lendacká M, Vandenberg J, Cullen A. Personal exposure to particles in Banská Bystrica, Slovakia. J Expo Anal Environ Epidemiol 2000; 10:478-87. [PMID: 11051537 DOI: 10.1038/sj.jea.7500136] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/15/2023]
Abstract
Epidemiological studies have associated adverse health impacts with ambient concentrations of particulate matter (PM), though these studies have been limited in their characterization of personal exposure to PM. An exposure study of healthy nonsmoking adults and children was conducted in Banska Bystrica, Slovakia, to characterize the range of personal exposures to air pollutants and to determine the influence of occupation, season, residence location, and outdoor and indoor concentrations on personal exposures. Twenty-four-hour personal, at-home indoor, and ambient measurements of PM10, PM2.5, sulfate (SO4(2-)) and nicotine were obtained for 18 office workers, 16 industrial workers, and 15 high school students in winter and summer. Results showed that outdoor levels of pollutants were modest, with clear seasonal differences: outdoor PM10 summer/winter mean = 35/45 microg/m3; PM2.5 summer/winter mean = 22/32 microg/m3. SO4(2-) levels were low (4-7 microg/m3) and relatively uniform across the different sample types (personal, indoor, outdoor), areas, and occupational groups. This suggests that SO4(2-) may be a useful marker for combustion mode particles of ambient origin, although the relationship between personal exposures and ambient SO4(2-) levels was more complex than observed in North American settings. During winter especially, the central city area showed higher concentrations than the suburban location for outdoor, personal, and indoor measures of PM10, PM2.5, and to a lesser extent for SO4(2-), suggesting the importance of local sources. For PM2.5 and PM10, ratios consistent with expectations were found among exposure indices for all three subject groups (personal>indoor>outdoor), and between work type (industrial>students>office workers). The ratio of PM2.5 personal to indoor exposures ranged from 1.0 to 3.9 and of personal to outdoor exposures from 1.6 to 4.2. The ratio of PM10 personal to indoor exposures ranged from 1.1 to 2.9 and the ratio of personal to outdoor exposures from 2.1 to 4.1. For a combined group of office workers and students, personal PM10/PM2.5 levels were predicted by statistically significant multivariate models incorporating indoor (for PM2.5) or outdoor (for PM10) PM levels, and nicotine exposure (for PM10). Small but significant fractions of the overall variability, 15% for PM2.5 and 17% for PM10, were explained by these models. The results indicate that central site monitors underpredict actual human exposures to PM2.5 and PM10. Personal exposure to SO4(2-) was found to be predicted by outdoor or indoor SO4(2-) levels with 23-71% of the overall variability explained by these predictors. We conclude that personal exposure measurements and additional demographic and daily activity data are crucial for accurate evaluation of exposure to particles in this setting.
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Affiliation(s)
- M Brauer
- School of Occupational and Environmental Hygiene, The University of British Columbia, Vancouver, Canada.
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Vandenberg J, van der Gun JW, Hendriksen CF. Evaluation of toxin neutralisation in test systems for diphtheria antibody assessment. Dev Biol Stand 1999; 101:105-11. [PMID: 10566782] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/14/2023]
Abstract
Over the past years, various authors have reported that the amount of toxin used in toxin neutralisation (TN) assays for diphtheria appears to influence the resulting relative antibody titre. Antibody affinity is thought to be an influencing factor. To confirm this observation and study the underlying mechanism of toxin neutralisation, a panel of sera was generated, differing in species of origin (mouse, guinea pig, and rabbit) and in affinity by using different immunisation schedules. The panel was then tested in relevant TN test systems for diphtheria antibody titration, namely the VERO cell test, the Toxin Binding Inhibition (ToBI) assay and the in vivo skin test in guinea pigs. A hyperimmune equine reference serum was used as the standard. Antibody affinity was measured in two different affinity ELISAs, the ammonium thiocyanate elution ELISA and the diethylamine inhibition ELISA. The VERO cell test clearly demonstrates the phenomenon; the higher the toxin dose used in the assay, the higher the resulting relative potency. The difference in relative antibody titre decreases as antibody affinity increases. This is especially evident when an equine hyperimmune reference serum is used as the standard. When a species homologous reference is used, the phenomenon is less distinct. The ToBI test, however, does not show the phenomenon. This discrepancy between these two test systems is being further investigated, and comparison will be made with the in vivo TN test. The findings confirm and support earlier observations. It is still unclear exactly which mechanisms are involved in the toxin neutralisation process. Antibody subclasses and class switching could play a role and will be further studied.
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Affiliation(s)
- J Vandenberg
- Department of Control of Biologicals, National Institute of Public Health and the Environment (RIVM), Bilthoven, The Netherlands
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Nasidi A, Monath TP, Vandenberg J, Tomori O, Calisher CH, Hurtgen X, Munube GR, Sorungbe AO, Okafor GC, Wali S. Yellow fever vaccination and pregnancy: a four-year prospective study. Trans R Soc Trop Med Hyg 1993; 87:337-9. [PMID: 8236412 DOI: 10.1016/0035-9203(93)90156-k] [Citation(s) in RCA: 98] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
During an outbreak of yellow fever (YF) in Nigeria in 1986-1987, women at various stages of pregnancy were vaccinated against YF, either because those pregnancies were not known at the time or because they requested vaccination out of fear of acquiring the disease. This offered an opportunity to assess the safety and efficacy of YF vaccine in pregnant women and the effect of this vaccine on their newborn children. Pre-vaccination and post-vaccination serum samples from the vaccinated pregnant women were tested by enzyme-linked immunosorbent assay and by neutralization tests for antibody to YF virus. The results showed that the antibody responses of these pregnant women were much lower than those of YF-vaccinated, non-pregnant women in a comparable control group. Follow-up of these women and their newborn children for 3-4 years showed no abnormal effect that could be attributed to the YF vaccine, which suggests that vaccination of pregnant women, particularly during a YF epidemic, may not be contraindicated.
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Affiliation(s)
- A Nasidi
- Federal Vaccine Production Laboratory, P.M.B., Yaba, Lagos, Nigeria
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Pease W, Vandenberg J, Hooper K. Comparing alternative approaches to establishing regulatory levels for reproductive toxicants: DBCP as a case study. Environ Health Perspect 1991; 91:141-155. [PMID: 2040244 PMCID: PMC1519361 DOI: 10.1289/ehp.9191141] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
This paper compares four alternative approaches for deriving regulatory levels for reproductive toxicants by applying them to the available data on the human spermatotoxicant 1,2-dibromo-3-chloropropane (DBCP). The alternatives examined include the Proposition 65 approach (application of a mandatory 1000-fold uncertainty factor to a no-observed-adverse-effect level [NOAEL]), the Environmental Protection Agency (EPA) approach (application of flexible uncertainty factors to a NOAEL), the Benchmark Dose approach (application of flexible uncertainty factors to a dose associated with a known level of change in a reproductive parameter), and the Quantitative Risk Estimation approach (using low-dose linear extrapolation and a model of the relationship between sperm count and infertility). Applied to DBCP, these approaches do not produce substantially different estimates of allowable exposure levels. However, the approaches do have different data requirements and provide different amounts of information on reproductive hazards to risk managers and the public. Neither the Proposition 65 nor the EPA approach provides information about the extent of health risk remaining at a regulatory level. In contrast, the Benchmark Dose approach can provide estimates of the magnitude of sperm count reduction at a regulatory level, and the Quantitative Risk Estimation approach can provide estimates of exposure-induced infertility.
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Affiliation(s)
- W Pease
- Environmental Health Sciences, School of Public Health, University of California, Berkeley 94720
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