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Håberg A, Qu H, Sonnewald U. Glutamate and GABA metabolism in transient and permanent middle cerebral artery occlusion in rat: Importance of astrocytes for neuronal survival. Neurochem Int 2006; 48:531-40. [PMID: 16504342 DOI: 10.1016/j.neuint.2005.12.025] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2005] [Revised: 12/20/2005] [Accepted: 12/22/2005] [Indexed: 10/25/2022]
Abstract
The aim of the present study was to identify the distinguishing metabolic characteristics of brain tissue salvaged by reperfusion following focal cerebral ischemia. Rats were subjected to 120 min of middle cerebral artery occlusion followed by 120 min of reperfusion. The rats received an intravenous bolus injection of [1-(13)C]glucose plus [1,2-(13)C]acetate. Subsequently two brain regions considered to represent penumbra and ischemic core, i.e. the frontoparietal cortex and the lateral caudoputamen plus lower parietal cortex, respectively, were analyzed with (13)C NMRS and HPLC. The results demonstrated four metabolic events that distinguished the reperfused penumbra from the ischemic core. (1) Improved astrocytic metabolism demonstrated by increased amounts of [4,5-(13)C]glutamine and improved acetate oxidation. (2) Neuronal mitochondrial activity was better preserved although the flux of glucose via pyruvate dehydrogenase into the tricarboxylic acid (TCA) cycle in glutamatergic and GABAergic neurons was halved. However, NAA content was at control level. (3) Glutamatergic and GABAergic neurons used relatively more astrocytic metabolites derived from the pyruvate carboxylase pathway. (4) Lactate synthesis was not increased despite decreased glucose metabolism in the TCA cycle via pyruvate dehydrogenase. In the ischemic core both neuronal and astrocytic TCA cycle activity declined significantly despite reperfusion. The utilization of astrocytic precursors originating from the pyruvate carboxylase pathway was markedly reduced compared the pyruvate dehydrogenase pathway in glutamate, and completely stopped in GABA. The NAA level fell significantly and lactate accumulated. The results demonstrate that preservation of astrocytic metabolism is essential for neuronal survival and a predictor for recovery.
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Affiliation(s)
- A Håberg
- Department of Circulation and Medical Imaging, Norwegian University of Science and Technology, NTNU, Trondheim, Norway.
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2
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Hara H, Yamada N, Kodama M, Matsumoto Y, Wake Y, Kuroda S. Effect of YM872, a selective and highly water-soluble AMPA receptor antagonist, in the rat kindling and rekindling model of epilepsy. Eur J Pharmacol 2006; 531:59-65. [PMID: 16403498 DOI: 10.1016/j.ejphar.2005.11.044] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2005] [Revised: 11/17/2005] [Accepted: 11/22/2005] [Indexed: 11/19/2022]
Abstract
We examined antiepileptogenic and anticonvulsant effects of [2,3-dioxo-7-(1H-imidazol-1-yl)-6-nitro-1,2,3,4-tetrahydro-1-quinoxalinyl]-acetic acid monohydrate (YM872), a potent and highly water-soluble alpha-amino-3-hydroxy-5-methyl-isoxazole-4-propionic acid (AMPA) receptor antagonist, in the rat amygdala kindling model of epilepsy. Administration of YM872 significantly suppressed fully kindled seizures. Daily pretreatment with YM872 markedly retarded development of kindling during drug sessions. We also used the rekindling method to investigate the antiepileptogenic effect of YM872 in an attempt to differentiate between true and false effects in the conventional method of daily administration. The results using the rekindling method suggested that the effect of YM872 was truly antiepileptogenic, indicating its possible clinical usefulness as an antiepileptogenic drug. We also affirmed the importance of AMPA receptors in the seizure expression mechanism and development of kindling-induced epileptogenesis.
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Affiliation(s)
- Hiroshi Hara
- Department of Neuropsychiatry, Okayama University Graduate School of Medicine and Dentistry, 2-5-1 Okayama City, Okayama 700-8558, Japan
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3
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Suzuki M, Sasamata M, Miyata K. Neuroprotective effects of YM872 coadministered with t-PA in a rat embolic stroke model. Brain Res 2003; 959:169-72. [PMID: 12480171 DOI: 10.1016/s0006-8993(02)03759-9] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
YM872, an AMPA receptor antagonist, was administered together with t-PA to investigate the effects of coadministration on neuroprotection in a rat embolic stroke model, when administered 2 h after embolism. T-PA or YM872 alone decreased infarct volume and improved the neurological deficit score. Coadministration of YM872 and t-PA resulted in a further decrease in infarct volume and improvement of the neurological score as compared with single administration of t-PA. These data demonstrate that coadministration of YM872 and t-PA produces more potent neuroprotective effects than when t-PA is administered alone.
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Affiliation(s)
- Masanori Suzuki
- Applied Pharmacology Research, Pharmacology Laboratories, Institute for Drug Discovery Research, Yamanouchi Pharmaceutical Co., Ltd., 21 Miyukigaoka, Tsukuba, Ibaraki 305-8585, Japan.
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4
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Legos JJ, Tuma RF, Barone FC. Pharmacological interventions for stroke: failures and future. Expert Opin Investig Drugs 2002; 11:603-14. [PMID: 11996643 DOI: 10.1517/13543784.11.5.603] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Given the few options currently available for patients following ischaemic stroke, the recent disappointing failures of several large-scale Phase III clinical trials has made the search for novel therapeutic approaches even more critical. Experimental evidence has suggested that the majority of stroke patients have a slow evolution of brain injury which can occur over several hours. Progressive microcirculatory failure following the initial onset of ischaemia may contribute to the expansion of brain injury. Included among the pathophysiological changes that are speculated to occur as a secondary response to the initial ischaemia are free radical production, excitotoxicity (for example, glutamate) disruption of ionic homeostasis (for example, sodium and calcium influx), enzymatic changes, stimulation of the inflammatory process, endothelin release, activation of platelets and leukocytes, delayed coagulation and endothelial dysfunction. All of these pathophysiological reactions could contribute to an increase in local vascular resistance and therefore cause progressive hypoperfusion of the brain following the onset of stroke. The scope of this review will focus on recent clinical failures in addition to agents currently in clinical development, comparing vascular targets to the common neuroprotective strategies.
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Affiliation(s)
- Jeffrey J Legos
- High Throughput Biology, Discovery Research, GlaxoSmithKline, King of Prussia, PA, USA.
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Mignani S, Bohme GA, Birraux G, Boireau A, Jimonet P, Damour D, Genevois-Borella A, Debono MW, Pratt J, Vuilhorgne M, Wahl F, Stutzmann JM. 9-Carboxymethyl-5H,10H-imidazo[1,2-a]indeno[1,2-e]pyrazin-4-one-2-carbocylic acid (RPR117824): selective anticonvulsive and neuroprotective AMPA antagonist. Bioorg Med Chem 2002; 10:1627-37. [PMID: 11886824 DOI: 10.1016/s0968-0896(01)00431-x] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Excessive release of glutamate, a potent excitatory neurotransmitter, is thought to play an important role in a variety of acute and chronic neurological disorders, suggesting that excitatory amino acid antagonists may have broad therapeutic potential in neurology. Here, we describe the synthesis, pharmacological properties and neuroprotective activity of 9-carboxymethyl-imidazo-[1-2a]indeno[1-2e]pyrazin-4-one-2-carboxylic acid (RPR117824), an original selective AMPA antagonist. RPR117824 can be obtained through a six-step synthesis starting from (1-oxo-indan-4-yl) acetic acid, which has been validated on a gram-scale with an overall yield of 25%. Monosodium or disodium salts of the compound exhibit excellent solubility in saline (> or = 10 g/L), enabling intravenous administration. RPR117824 displays nanomolar affinity (IC(50)=18 nM) for AMPA receptors and competitive inhibition of electrophysiological responses mediated by AMPA receptors heterologously expressed in Xenopus oocytes (K(B)=5 nM) and native receptors in rat brain slices (IC(50)=0.36 microM). In in vivo testing, RPR117824 behaves as a powerful blocker of convulsions induced in mice or rats by supramaximal electroshock or chemoconvulsive agents such as pentylenetetrazole, bicuculline, isoniazide, strychnine, 4-aminopyridine and harmaline with half maximal effective doses ranging from 1.5 to 10 mg/kg following subcutaneous or intraperitoneal administration. In disease models in rats and gerbils, RPR117824 possesses significant neuroprotective activity in global and focal cerebral ischemia, and brain and spinal cord trauma.
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Affiliation(s)
- Serge Mignani
- Aventis Pharma S.A., Centre de Recherche de Paris, Vitry-sur-Seine Cedex, France.
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6
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Yoneda Y, Mimura T, Kawagoe K, Yasukouchi T, Tatematu T, Ito M, Saito M, Sugimura M, Kito F, Kawajiri S. Discovery of diaminobutane derivatives as Ca(2+)-permeable AMPA receptor antagonists. Bioorg Med Chem 2002; 10:1347-59. [PMID: 11886798 DOI: 10.1016/s0968-0896(01)00398-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We designed and synthesized a series of the polyamine derivatives as potent Ca(2+)-permeable AMPA receptor antagonists. In the course of this study, we found that the polyamine derivatives exhibited strong hypotensive activity which was undesirable activity for neuroprotective agents. Therefore, we tried to find non-hypotensive antagonists by structural modification of such compounds. Through this derivatization, we obtained the diamine compounds having desired profiles. Especially, compound 8f, which was non-hypotensive and potent Ca(2+)-permeable AMPA receptor antagonist, showed neuroprotective effects in transient global ischemia models in gerbils.
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Affiliation(s)
- Yoshiyuki Yoneda
- Medicinal Chemistry Research Laboratory, Daiichi Pharmaceutical Co., Ltd., 16-13, Kitakasai 1-Chome, Edogawa-ku, 134-8630, Tokyo, Japan.
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7
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Abstract
During cerebral ischaemia, glutamate is released in supraphysiological amounts and is toxic to brain tissue. This excitotoxicity is mediated by several glutamate receptor subtypes, including the ionotropic N-methyl-D-aspartate (NMDA) and alpha-amino-3-hydroxy-5-methylisoxazole-4-propionic acid (AMPA) receptors. Clinical trials of drugs that block the NMDA receptor in acute ischaemic stroke have been disappointing. No improvement in clinical outcome of stroke has been seen with competitive NMDA antagonists (selfotel) and non-competitive NMDA antagonists (dextrorphan, GV150526, aptiganel and eliprodil). The AMPA receptor differs in important ways from the NMDA receptor. It is the principal mediator of fast excitatory neurotransmission. This ligand-gated cation channel is primarily permeable to sodium rather than calcium. It is found in grey and white matter. It is expressed by oligodendrocytes. This distribution may provide neuroprotection for both grey and white matter. In a variety of animal models, reduction in infarct volume with AMPA blockade has been demonstrated. AMPA antagonists also show benefit in spinal cord ischaemia and trauma. The clinical development of safe and effective AMPA blockers has been hampered by poor water solubility and associated renal toxicity. A novel, highly water-soluble, competitive AMPA receptor antagonist, YM872 ([2,3-dioxo-7-(1H-imidazol-1-yl)-6-nitro-1,2,3,4-tetrahydroquinoxalin-1-yl]acetic acid monohydrate; Yamanouchi), has been identified. Phase I clinical trial data indicate that this agent can be safely administered in young and elderly subjects. Sedation and other CNS associated adverse events determine the ceiling dose and become more problematic with infusion times exceeding 24 h. Phase II studies of YM872 in acute ischaemic stroke are ongoing.
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Håberg A, Qu H, Saether O, Unsgård G, Haraldseth O, Sonnewald U. Differences in neurotransmitter synthesis and intermediary metabolism between glutamatergic and GABAergic neurons during 4 hours of middle cerebral artery occlusion in the rat: the role of astrocytes in neuronal survival. J Cereb Blood Flow Metab 2001; 21:1451-63. [PMID: 11740207 DOI: 10.1097/00004647-200112000-00010] [Citation(s) in RCA: 63] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Astrocytes are intimately involved in both glutamate and gamma-aminobutyric acid (GABA) synthesis, and ischemia-induced disruption of normal neuroastrocytic interactions may have important implications for neuronal survival. The effects of middle cerebral artery occlusion (MCAO) on neuronal and astrocytic intermediary metabolism were studied in rats 30, 60, 120, and 240 minutes after MCAO using in vivo injection of [1-13C]glucose and [1,2- 13C]acetate combined with ex vivo 13C magnetic resonance spectroscopy and high-performance liquid chromatography analysis of the ischemic core (lateral caudoputamen and lower parietal cortex) and penumbra (upper frontoparietal cortex). In the ischemic core, both neuronal and astrocytic metabolism were impaired from 30 minutes MCAO. There was a continuous loss of glutamate from glutamatergic neurons that was not replaced as neuronal glucose metabolism and use of astrocytic precursors gradually declined. In GABAergic neurons astrocytic precursors were not used in GABA synthesis at any time after MCAO, and neuronal glucose metabolism and GABA-shunt activity declined with time. No flux through the tricarboxylic acid cycle was found in GABAergic neurons at 240 minutes MCAO, indicating neuronal death. In the penumbra, the neurotransmitter pool of glutamate coming from astrocytic glutamine was preserved while neuronal metabolism progressively declined, implying that glutamine contributed significantly to glutamate excitotoxicity. In GABAergic neurons, astrocytic precursors were used to a limited extent during the initial 120 minutes, and tricarboxylic acid cycle activity was continued for 240 minutes. The present study showed the paradoxical role that astrocytes play in neuronal survival in ischemia, and changes in the use of astrocytic precursors appeared to contribute significantly to neuronal death, albeit through different mechanisms in glutamatergic and GABAergic neurons.
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Affiliation(s)
- A Håberg
- Departments of Clinical Neuroscience, Norwegian University of Science and Technology, Trondheim, Norway
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Stutzmann JM, Bohme GA, Boireau A, Damour D, Debono MW, Genevois-Borella A, Jimonet P, Pratt J, Randle JC, Ribeill Y, Vuilhorgne M, Mignani S. Synthesis of anticonvulsive AMPA antagonists. Bioorg Med Chem Lett 2001; 11:1205-10. [PMID: 11354378 DOI: 10.1016/s0960-894x(01)00180-9] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The overstimulation of excitatory amino acid receptors such as the glutamate AMPA receptor has been implicated in the physiopathogenesis of epilepsy as well as in acute and chronic neurodegenerative disorders. An original series of readily water soluble 4-oxo-10-substituted-imidazo[1,2-a]indeno[1,2-e]pyrazin-2-carboxylic acid derivatives was synthesized. The most potent derivative 6a exhibited nanomolar binding affinity (IC50 = 35nM) and antagonist activity (IC50 = 6nM) at ionotropic AMPA receptor. This compound also demonstrated potent anticonvulsant properties in MES in mice and rats with long durations of action with ED50 values in the 1-3 mg/kg dose range following ip and iv administration.
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Affiliation(s)
- J M Stutzmann
- Aventis Pharma S.A., Centre de Recherche de Vitry-Alfortville, Vitry-sur-Seine, France
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10
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Warach S, Creed Pettigrew L, Dashe JF, Pullicino P, Lefkowitz DM, Sabounjian L, Harnett K, Schwiderski U, Gammans R. Effect of citicoline on ischemic lesions as measured by diffusion‐weighted magnetic resonance imaging. Ann Neurol 2001. [DOI: 10.1002/1531-8249(200011)48:5<713::aid-ana4>3.0.co;2-#] [Citation(s) in RCA: 160] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- S. Warach
- National Institute of of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD
| | - L. Creed Pettigrew
- National Institute of of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD
| | - J. F. Dashe
- National Institute of of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD
| | - P. Pullicino
- National Institute of of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD
| | - David M. Lefkowitz
- National Institute of of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD
| | - L. Sabounjian
- National Institute of of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD
| | - K. Harnett
- National Institute of of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD
| | - U. Schwiderski
- National Institute of of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD
| | - R. Gammans
- National Institute of of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD
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11
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Jimonet P, Bohme GA, Bouquerel J, Boireau A, Damour D, Debono MW, Genevois-Borella A, Hardy JC, Hubert P, Manfré F, Nemecek P, Pratt J, Randle JC, Ribeill Y, Stutzmann JM, Vuilhorgne M, Mignani S. Bioisosteres of 9-carboxymethyl-4-oxo-imidazo[1,2-a]indeno-[1,2-e]pyrazin-2-carboxylic acid derivatives. Progress towards selective, potent in vivo AMPA antagonists with longer durations of action. Bioorg Med Chem Lett 2001; 11:127-32. [PMID: 11206442 DOI: 10.1016/s0960-894x(00)00592-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
A novel series of 2- and 9-disubstituted heterocyclic-fused 4-oxo-indeno[1,2-e]pyrazin derivatives was synthesized. One of them, the 9-(1H-tetrazol-5-ylmethyl)-4-oxo-5,10-dihydroimidazo[1,2-a]indeno[1,2-e]pyrazin-2-yl phosphonic acid 4i exhibited a strong and a selective binding affinity for the AMPA receptor (IC50 = 13 nM) and demonstrated potent antagonist activity (IC50 = 6nM) at the ionotropic AMPA receptor. This compound also displayed good anticonvulsant properties against electrically-induced convulsions after ip and iv administration with ED50 values between 0.8 and 1 mg/kg. Furthermore, a strong increase in potency was observed when given iv 3 h before test (ED50 = 3.5 instead of 25.6 mg/kg for the corresponding 9-carboxymethyl-2-carboxylic acid analogue). These data confirmed that there is an advantage in replacing the classical carboxy substituents by their bioisosteres such as tetrazole or phosphonic acid groups.
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Affiliation(s)
- P Jimonet
- Aventis Pharma S.A., Centre de Recherche de Vitry-Alfortville, Vitry-sur-Seine, France
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12
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Abstract
With the approval of alteplase (tPA) therapy for stroke, it is likely that combination therapy with tPA to restore blood flow, and agents like glutamate receptor antagonists to halt or reverse the cascade of neuronal damage, will dominate the future of stroke care. The authors describe events and potential targets of therapeutic intervention that contribute to the excitotoxic cascade underlying cerebral ischemic cell death. The focal and global animal models of stroke are the basis for the identification of these events and therapeutic targets. The signalling pathways contributing to ischemic neuronal death are discussed based on their cellular localization. Cell surface signalling events include the activities of both voltage-gated K+, Na+, and Ca2+ channels and ligand-gated glutamate, gamma-aminobutyric acid and adenosine receptors and channels. Intracellular signalling events include alterations in cytosolic and subcellular Ca2+ dynamics, Ca2+ -dependent kinases and immediate early genes whereas intercellular mechanisms include free radical formation and the activation of the immune system. An understanding of the relative importance and temporal sequence of these processes may result in an effective stroke therapy targeting several points in the cascade. The overall goal is to reduce disability and enhance quality of life for stroke survivors.
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Affiliation(s)
- D L Small
- Receptor and Ion Channels Group, Institute for Biological Sciences, National Research Council of Canada, Ottawa, Ontario.
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