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Canet G, Gratuze M, Zussy C, Bouali ML, Diaz SD, Rocaboy E, Laliberté F, El Khoury NB, Tremblay C, Morin F, Calon F, Hébert SS, Julien C, Planel E. Age-dependent impact of streptozotocin on metabolic endpoints and Alzheimer's disease pathologies in 3xTg-AD mice. Neurobiol Dis 2024:106526. [PMID: 38734152 DOI: 10.1016/j.nbd.2024.106526] [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] [Subscribe] [Scholar Register] [Received: 03/26/2024] [Revised: 05/06/2024] [Accepted: 05/07/2024] [Indexed: 05/13/2024] Open
Abstract
Alzheimer's disease (AD) is a multifactorial neurodegenerative disease with a complex origin, thought to involve a combination of genetic, biological and environmental factors. Insulin dysfunction has emerged as a potential factor contributing to AD pathogenesis, particularly in individuals with diabetes, and among those with insulin deficiency or undergoing insulin therapy. The intraperitoneal administration of streptozotocin (STZ) is a widely used rodent model to explore the impact of insulin deficiency on AD pathology, although prior research predominantly focused on young animals, with no comparative analysis across different age groups. Our study aimed to fill this gap by analyzing the impact of insulin dysfunction in 7 and 23 months 3xTg-AD mice, that exhibit both amyloid and tau pathologies. Our objective was to elucidate the age-specific consequences of insulin deficiency on AD pathology. STZ administration led to insulin deficiency in the younger mice, resulting in an increase in cortical amyloid-β (Aβ) and tau aggregation, while tau phosphorylation was not significantly affected. Conversely, older mice displayed an unexpected resilience to the peripheral metabolic impact of STZ, while exhibiting an increase in both tau phosphorylation and aggregation without significantly affecting amyloid pathology. These changes were paralleled with alterations in signaling pathways involving tau kinases and phosphatases. Several markers of blood-brain barrier (BBB) integrity declined with age in 3xTg-AD mice, which might facilitate a direct neurotoxic effect of STZ in older mice. Overall, our research confirms the influence of insulin signaling dysfunction on AD pathology, but also advises careful interpretation of data related to STZ-induced effects in older animals.
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Affiliation(s)
- Geoffrey Canet
- Laval University, Faculty of Medicine, Neurosciences and Psychiatry department, Québec, QC G1V 0A6, Canada; Neurosciences axis, CHU de Québec Research Center, Québec, QC G1V 4G2, Canada.
| | - Maud Gratuze
- Laval University, Faculty of Medicine, Neurosciences and Psychiatry department, Québec, QC G1V 0A6, Canada; Institute of Neurophysiopathology (INP), University of Aix-Marseille, CNRS UMR 7051, 13385 Marseille, France.
| | - Charleine Zussy
- Laval University, Faculty of Medicine, Neurosciences and Psychiatry department, Québec, QC G1V 0A6, Canada; Neurosciences axis, CHU de Québec Research Center, Québec, QC G1V 4G2, Canada.
| | - Mohamed Lala Bouali
- Laval University, Faculty of Medicine, Neurosciences and Psychiatry department, Québec, QC G1V 0A6, Canada.
| | - Sofia Diego Diaz
- Laval University, Faculty of Medicine, Neurosciences and Psychiatry department, Québec, QC G1V 0A6, Canada.
| | - Emma Rocaboy
- Laval University, Faculty of Medicine, Neurosciences and Psychiatry department, Québec, QC G1V 0A6, Canada.
| | - Francis Laliberté
- Neurosciences axis, CHU de Québec Research Center, Québec, QC G1V 4G2, Canada
| | - Noura B El Khoury
- Laval University, Faculty of Medicine, Neurosciences and Psychiatry department, Québec, QC G1V 0A6, Canada; University of Balamand, Faculty of Arts and Sciences, Departement of Psychology, Tueini Building Kalhat, Al-Kurah, P.O. Box 100, Tripoli, Lebanon.
| | - Cyntia Tremblay
- Neurosciences axis, CHU de Québec Research Center, Québec, QC G1V 4G2, Canada.
| | - Françoise Morin
- Neurosciences axis, CHU de Québec Research Center, Québec, QC G1V 4G2, Canada.
| | - Frédéric Calon
- Neurosciences axis, CHU de Québec Research Center, Québec, QC G1V 4G2, Canada; Laval University, Faculty of Pharmacy, Neurosciences and Psychiatry department, Québec, QC G1V 0A6, Canada.
| | - Sébastien S Hébert
- Laval University, Faculty of Medicine, Neurosciences and Psychiatry department, Québec, QC G1V 0A6, Canada; Neurosciences axis, CHU de Québec Research Center, Québec, QC G1V 4G2, Canada.
| | - Carl Julien
- Research Center in Animal Sciences of Deschambault, Québec, QC G0A 1S0, Canada; Laval University, Faculty of Agricultural and Food Sciences, Québec, QC G1V 0A6, Canada.
| | - Emmanuel Planel
- Laval University, Faculty of Medicine, Neurosciences and Psychiatry department, Québec, QC G1V 0A6, Canada; Neurosciences axis, CHU de Québec Research Center, Québec, QC G1V 4G2, Canada.
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Canet G, Rocaboy E, Laliberté F, Boscher E, Guisle I, Diego-Diaz S, Fereydouni-Forouzandeh P, Whittington RA, Hébert SS, Pernet V, Planel E. Temperature-induced Artifacts in Tau Phosphorylation: Implications for Reliable Alzheimer's Disease Research. Exp Neurobiol 2023; 32:423-440. [PMID: 38196137 PMCID: PMC10789175 DOI: 10.5607/en23025] [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] [Subscribe] [Scholar Register] [Received: 08/04/2023] [Revised: 12/10/2023] [Accepted: 12/19/2023] [Indexed: 01/11/2024] Open
Abstract
In preclinical research on Alzheimer's disease and related tauopathies, tau phosphorylation analysis is routinely employed in both cellular and animal models. However, recognizing the sensitivity of tau phosphorylation to various extrinsic factors, notably temperature, is vital for experimental accuracy. Hypothermia can trigger tau hyperphosphorylation, while hyperthermia leads to its dephosphorylation. Nevertheless, the rapidity of tau phosphorylation in response to unintentional temperature variations remains unknown. In cell cultures, the most significant temperature change occurs when the cells are removed from the incubator before harvesting, and in animal models, during anesthesia prior to euthanasia. In this study, we investigate the kinetics of tau phosphorylation in N2a and SH-SY5Y neuronal cell lines, as well as in mice exposed to anesthesia. We observed changes in tau phosphorylation within the few seconds upon transferring cell cultures from their 37°C incubator to room temperature conditions. However, cells placed directly on ice post-incubation exhibited negligible phosphorylation changes. In vivo, isoflurane anesthesia rapidly resulted in tau hyperphosphorylation within the few seconds needed to lose the pedal withdrawal reflex in mice. These findings emphasize the critical importance of preventing temperature variation in researches focused on tau. To ensure accurate results, we recommend avoiding anesthesia before euthanasia and promptly placing cells on ice after removal from the incubator. By controlling temperature fluctuations, the reliability and validity of tau phosphorylation studies can be significantly enhanced.
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Affiliation(s)
- Geoffrey Canet
- Department of Psychiatry and Neurosciences, Faculty of Medicine, Laval University, Québec G1V 4G2, Canada
- Neurosciences Axis, Research Center of the CHU de Québec - Laval University, Québec G1V 4G2, Canada
| | - Emma Rocaboy
- Department of Psychiatry and Neurosciences, Faculty of Medicine, Laval University, Québec G1V 4G2, Canada
| | - Francis Laliberté
- Neurosciences Axis, Research Center of the CHU de Québec - Laval University, Québec G1V 4G2, Canada
| | - Emmanuelle Boscher
- Neurosciences Axis, Research Center of the CHU de Québec - Laval University, Québec G1V 4G2, Canada
| | - Isabelle Guisle
- Neurosciences Axis, Research Center of the CHU de Québec - Laval University, Québec G1V 4G2, Canada
| | - Sofia Diego-Diaz
- Department of Psychiatry and Neurosciences, Faculty of Medicine, Laval University, Québec G1V 4G2, Canada
| | | | - Robert A. Whittington
- Department of Anesthesiology and Perioperative Medicine, UCLA, Los Angeles, CA 90095, USA
| | - Sébastien S. Hébert
- Department of Psychiatry and Neurosciences, Faculty of Medicine, Laval University, Québec G1V 4G2, Canada
- Neurosciences Axis, Research Center of the CHU de Québec - Laval University, Québec G1V 4G2, Canada
| | - Vincent Pernet
- Department of Psychiatry and Neurosciences, Faculty of Medicine, Laval University, Québec G1V 4G2, Canada
- Department of Neurology, Bern University Hospital, Bern 3010, Switzerland
| | - Emmanuel Planel
- Department of Psychiatry and Neurosciences, Faculty of Medicine, Laval University, Québec G1V 4G2, Canada
- Neurosciences Axis, Research Center of the CHU de Québec - Laval University, Québec G1V 4G2, Canada
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Averell C, Germain G, Laliberté F, Duh M, Lima R, Slade D. P218 ASTHMA-RELATED EXACERBATIONS AND SABA USE ASSOCIATED WITH ONCE-DAILY FLUTICASONE FUROATE/VILANTEROL COMPARED TO TWICE-DAILY BUDESONIDE/FORMOTEROL. Ann Allergy Asthma Immunol 2020. [DOI: 10.1016/j.anai.2020.08.115] [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: 10/23/2022]
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Grissonnanche G, Legros A, Badoux S, Lefrançois E, Zatko V, Lizaire M, Laliberté F, Gourgout A, Zhou JS, Pyon S, Takayama T, Takagi H, Ono S, Doiron-Leyraud N, Taillefer L. Giant thermal Hall conductivity in the pseudogap phase of cuprate superconductors. Nature 2019; 571:376-380. [DOI: 10.1038/s41586-019-1375-0] [Citation(s) in RCA: 68] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2018] [Accepted: 04/26/2019] [Indexed: 11/09/2022]
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Laliberté F, Raut M, Duh M, Yang X, Germain G, Sen S, MacKnight S, Desai K, Armand P. REAL-WORLD HEALTHCARE RESOURCE UTILIZATION (HRU) OF CLASSICAL HODGKIN LYMPHOMA (cHL) PATIENTS (PTS) TREATED WITH ANTI-PD1 CHECKPOINT INHIBITORS IN THE UNITED STATES (US). Hematol Oncol 2019. [DOI: 10.1002/hon.175_2631] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- F. Laliberté
- Health Economics & Outcomes Research; Groupe d'analyse; Ltée Montréal Canada
| | - M. Raut
- Center for Observational and Real-World Evidence; Merck & Co., Inc.; Kenilworth United States
| | - M. Duh
- Health Economics & Outcomes Research; Analysis Group, Inc.; Boston United States
| | - X. Yang
- Center for Observational and Real-World Evidence; Merck & Co., Inc.; Kenilworth United States
| | - G. Germain
- Health Economics & Outcomes Research; Groupe d'analyse; Ltée Montréal Canada
| | - S. Sen
- Center for Observational and Real-World Evidence; Merck & Co., Inc.; Kenilworth United States
| | - S. MacKnight
- Health Economics & Outcomes Research; Groupe d'analyse; Ltée Montréal Canada
| | - K. Desai
- Center for Observational and Real-World Evidence; Merck & Co., Inc.; Kenilworth United States
| | - P. Armand
- Medical Oncology; Dana-Farber Cancer Institute; Boston United States
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Subramanian J, Laliberté F, Fernandes A, Pavilack M, Jacques P, Duh M. P2.15-26 Rates and Economic Burden of Adverse Events in Patients With Metastatic NSCLC Treated with EGFR-TKIs. J Thorac Oncol 2018. [DOI: 10.1016/j.jtho.2018.08.1468] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [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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Chiang A, Fernandes A, Pavilack M, Wu J, Laliberté F, Duh M, Chehab N, Subramanian J. MA15.11 Real World Biomarker Testing and Treatment Patterns in Patients with Advanced NSCLC Receiving EGFR-TKIs. J Thorac Oncol 2018. [DOI: 10.1016/j.jtho.2018.08.447] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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Law A, Pilon D, Lynen R, Laliberté F, Gozalo L, Lefebvre P, Duh M. Impact of the introduction of newer long-acting reversible contraceptive (LARC) methods on LARC use in a commercially insured population. Contraception 2015. [DOI: 10.1016/j.contraception.2015.06.088] [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: 10/23/2022]
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9
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Laliberté F, Zika J, Mudryk L, Kushner PJ, Kjellsson J, Döös K. Constrained work output of the moist atmospheric heat engine in a warming climate. Science 2015; 347:540-3. [DOI: 10.1126/science.1257103] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Affiliation(s)
- F. Laliberté
- Department of Physics, University of Toronto, Ontario, Canada
| | - J. Zika
- University of Southampton, National Oceanography Centre, Southampton, UK
| | - L. Mudryk
- British Antarctic Survey, Cambridge, UK
| | - P. J. Kushner
- Department of Physics, University of Toronto, Ontario, Canada
| | | | - K. Döös
- Department of Meteorology, Stockholm University, Stockholm, Sweden
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10
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Doiron-Leyraud N, Badoux S, René de Cotret S, Lepault S, LeBoeuf D, Laliberté F, Hassinger E, Ramshaw BJ, Bonn DA, Hardy WN, Liang R, Park JH, Vignolles D, Vignolle B, Taillefer L, Proust C. Evidence for a small hole pocket in the Fermi surface of underdoped YBa2Cu3Oy. Nat Commun 2015; 6:6034. [PMID: 25616011 PMCID: PMC4316745 DOI: 10.1038/ncomms7034] [Citation(s) in RCA: 56] [Impact Index Per Article: 6.2] [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: 07/25/2014] [Accepted: 12/04/2014] [Indexed: 11/09/2022] Open
Abstract
In underdoped cuprate superconductors, the Fermi surface undergoes a reconstruction that produces a small electron pocket, but whether there is another, as yet, undetected portion to the Fermi surface is unknown. Establishing the complete topology of the Fermi surface is key to identifying the mechanism responsible for its reconstruction. Here we report evidence for a second Fermi pocket in underdoped YBa2Cu3Oy, detected as a small quantum oscillation frequency in the thermoelectric response and in the c-axis resistance. The field-angle dependence of the frequency shows that it is a distinct Fermi surface, and the normal-state thermopower requires it to be a hole pocket. A Fermi surface consisting of one electron pocket and two hole pockets with the measured areas and masses is consistent with a Fermi-surface reconstruction by the charge-density-wave order observed in YBa2Cu3Oy, provided other parts of the reconstructed Fermi surface are removed by a separate mechanism, possibly the pseudogap.
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Affiliation(s)
- N Doiron-Leyraud
- Département de physique &RQMP, Université de Sherbrooke, Sherbrooke, Québec, Canada J1K 2R1
| | - S Badoux
- Laboratoire National des Champs Magnétiques Intenses (CNRS, INSA, UJF, UPS), 31400 Toulouse, France
| | - S René de Cotret
- Département de physique &RQMP, Université de Sherbrooke, Sherbrooke, Québec, Canada J1K 2R1
| | - S Lepault
- Laboratoire National des Champs Magnétiques Intenses (CNRS, INSA, UJF, UPS), 31400 Toulouse, France
| | - D LeBoeuf
- Laboratoire National des Champs Magnétiques Intenses (CNRS, INSA, UJF, UPS), 31400 Toulouse, France
| | - F Laliberté
- Département de physique &RQMP, Université de Sherbrooke, Sherbrooke, Québec, Canada J1K 2R1
| | - E Hassinger
- Département de physique &RQMP, Université de Sherbrooke, Sherbrooke, Québec, Canada J1K 2R1
| | - B J Ramshaw
- Department of Physics &Astronomy, University of British Columbia, Vancouver, British Columbia, Canada V6T 1Z1
| | - D A Bonn
- 1] Department of Physics &Astronomy, University of British Columbia, Vancouver, British Columbia, Canada V6T 1Z1 [2] Canadian Institute for Advanced Research, Toronto, Ontario, Canada M5G 1Z8
| | - W N Hardy
- 1] Department of Physics &Astronomy, University of British Columbia, Vancouver, British Columbia, Canada V6T 1Z1 [2] Canadian Institute for Advanced Research, Toronto, Ontario, Canada M5G 1Z8
| | - R Liang
- 1] Department of Physics &Astronomy, University of British Columbia, Vancouver, British Columbia, Canada V6T 1Z1 [2] Canadian Institute for Advanced Research, Toronto, Ontario, Canada M5G 1Z8
| | - J-H Park
- National High Magnetic Field Laboratory, Tallahassee, Florida 32310, USA
| | - D Vignolles
- Laboratoire National des Champs Magnétiques Intenses (CNRS, INSA, UJF, UPS), 31400 Toulouse, France
| | - B Vignolle
- Laboratoire National des Champs Magnétiques Intenses (CNRS, INSA, UJF, UPS), 31400 Toulouse, France
| | - L Taillefer
- 1] Département de physique &RQMP, Université de Sherbrooke, Sherbrooke, Québec, Canada J1K 2R1 [2] Canadian Institute for Advanced Research, Toronto, Ontario, Canada M5G 1Z8
| | - C Proust
- 1] Laboratoire National des Champs Magnétiques Intenses (CNRS, INSA, UJF, UPS), 31400 Toulouse, France [2] Canadian Institute for Advanced Research, Toronto, Ontario, Canada M5G 1Z8
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Olson WH, Ma YW, Laliberté F, Lefebvre P, Crivera C, Schein JR, Fields LE, Dea K, Germain G, Lynch SM. Prasugrel vs. clopidogrel in acute coronary syndrome patients treated with prasugrel. J Clin Pharm Ther 2014; 39:663-72. [DOI: 10.1111/jcpt.12209] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2014] [Accepted: 08/25/2014] [Indexed: 01/06/2023]
Affiliation(s)
- W. H. Olson
- Janssen Scientific Affairs; LLC; Raritan NJ USA
| | - Y.-W. Ma
- Johnson & Johnson Consumer Companies Inc.; Horsham PA USA
| | | | | | - C. Crivera
- Janssen Scientific Affairs; LLC; Raritan NJ USA
| | | | | | - K. Dea
- Groupe d'analyse, Ltée; Montréal QC Canada
| | - G. Germain
- Groupe d'analyse, Ltée; Montréal QC Canada
| | - S. M. Lynch
- Department of Sociology; Duke University; Durham NC USA
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12
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Laliberté F, Nutescu EA, Lefebvre P, Rondeau-Leclaire J, Bookhart BK, LaMori JC, Damaraju CV, Schein J, Kaatz S. Risk factors associated with myocardial infarction in venous thromboembolism patients. Curr Med Res Opin 2014; 30:27-35. [PMID: 24102370 DOI: 10.1185/03007995.2013.852525] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
BACKGROUND Although risk factors for MI have been described in the general population, there is a lack of data on the assessment of risk factors associated with MI in venous thromboembolism (VTE) patients. OBJECTIVE The purpose of this study was to identify risk factors associated with MI in VTE patients. PATIENTS AND METHODS Health insurance claims between January 2004 and September 2008 from the Ingenix IMPACT database were analyzed. Patients aged ≥18 years were identified as of the date of their first VTE diagnosis with ≥1 year of continuous insurance coverage before the index VTE. The risk of MI for VTE patients with 1, 2, and ≥3 major risk factors as identified by published guidelines was calculated. Multivariate Cox proportional hazard models were conducted to identify the most predictive risk factors associated with MI. RESULTS A total of 177,885 VTE patients were identified; 4412 (2.5%) developed an MI during a mean follow-up period of 1.3 years. Previous MI, age (≥65 years), and coronary artery disease were the most predictive risk factors of MI with adjusted hazard ratios (HRs; 95% CI) of 5.47 (5.01-5.97), 1.78 (1.66-1.91), and 1.60 (1.48-1.74), respectively. Adjusted HRs (95% CI) for VTE patients with 1, 2, and ≥3 major risk factors relative to no major risk factor were 2.34 (1.94-2.81), 3.21 (2.67-3.85), and 6.93 (5.85-8.22), respectively. LIMITATIONS These included possible inaccuracies or omissions in diagnoses, classification bias such as the identification of false-positive MI events, and the likely undercoding of some risk factors such as social issues. CONCLUSIONS Traditional major cardiovascular risk factors are also predictive of MI in VTE patients. Having multiple major risk factors significantly increases the probability of developing MI events in VTE patients.
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Affiliation(s)
- F Laliberté
- Groupe d'analyse , Ltée, Montréal, QC , Canada
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Grissonnanche G, Cyr-Choinière O, Laliberté F, René de Cotret S, Juneau-Fecteau A, Dufour-Beauséjour S, Delage MÈ, LeBoeuf D, Chang J, Ramshaw BJ, Bonn DA, Hardy WN, Liang R, Adachi S, Hussey NE, Vignolle B, Proust C, Sutherland M, Krämer S, Park JH, Graf D, Doiron-Leyraud N, Taillefer L. Direct measurement of the upper critical field in cuprate superconductors. Nat Commun 2014; 5:3280. [PMID: 24518054 PMCID: PMC3929805 DOI: 10.1038/ncomms4280] [Citation(s) in RCA: 147] [Impact Index Per Article: 14.7] [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: 08/13/2013] [Accepted: 01/19/2014] [Indexed: 11/08/2022] Open
Abstract
In the quest to increase the critical temperature Tc of cuprate superconductors, it is essential to identify the factors that limit the strength of superconductivity. The upper critical field Hc2 is a fundamental measure of that strength, yet there is no agreement on its magnitude and doping dependence in cuprate superconductors. Here we show that the thermal conductivity can be used to directly detect Hc2 in the cuprates YBa2Cu3Oy, YBa2Cu4O8 and Tl2Ba2CuO6+δ, allowing us to map out Hc2 across the doping phase diagram. It exhibits two peaks, each located at a critical point where the Fermi surface of YBa2Cu3Oy is known to undergo a transformation. Below the higher critical point, the condensation energy, obtained directly from Hc2, suffers a sudden 20-fold collapse. This reveals that phase competition-associated with Fermi-surface reconstruction and charge-density-wave order-is a key limiting factor in the superconductivity of cuprates.
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Affiliation(s)
- G. Grissonnanche
- Département de physique & RQMP, Université de Sherbrooke, Sherbrooke, Québec, Canada J1K 2R1
| | - O. Cyr-Choinière
- Département de physique & RQMP, Université de Sherbrooke, Sherbrooke, Québec, Canada J1K 2R1
| | - F. Laliberté
- Département de physique & RQMP, Université de Sherbrooke, Sherbrooke, Québec, Canada J1K 2R1
| | - S. René de Cotret
- Département de physique & RQMP, Université de Sherbrooke, Sherbrooke, Québec, Canada J1K 2R1
| | - A. Juneau-Fecteau
- Département de physique & RQMP, Université de Sherbrooke, Sherbrooke, Québec, Canada J1K 2R1
| | - S. Dufour-Beauséjour
- Département de physique & RQMP, Université de Sherbrooke, Sherbrooke, Québec, Canada J1K 2R1
| | - M. -È. Delage
- Département de physique & RQMP, Université de Sherbrooke, Sherbrooke, Québec, Canada J1K 2R1
| | - D. LeBoeuf
- Département de physique & RQMP, Université de Sherbrooke, Sherbrooke, Québec, Canada J1K 2R1
- Present address: Laboratoire National des Champs Magnétiques Intenses, Grenoble, France
| | - J. Chang
- Département de physique & RQMP, Université de Sherbrooke, Sherbrooke, Québec, Canada J1K 2R1
- Present address: École Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland
| | - B. J. Ramshaw
- Department of Physics & Astronomy, University of British Columbia, Vancouver, British Columbia, Canada V6T 1Z1
| | - D. A. Bonn
- Department of Physics & Astronomy, University of British Columbia, Vancouver, British Columbia, Canada V6T 1Z1
- Canadian Institute for Advanced Research, Toronto, Ontario, Canada M5G 1Z8
| | - W. N. Hardy
- Department of Physics & Astronomy, University of British Columbia, Vancouver, British Columbia, Canada V6T 1Z1
- Canadian Institute for Advanced Research, Toronto, Ontario, Canada M5G 1Z8
| | - R. Liang
- Department of Physics & Astronomy, University of British Columbia, Vancouver, British Columbia, Canada V6T 1Z1
- Canadian Institute for Advanced Research, Toronto, Ontario, Canada M5G 1Z8
| | - S. Adachi
- Superconductivity Research Laboratory, ISTEC, Yokohama, Kanagawa 223-0051, Japan
| | - N. E. Hussey
- H. H. Wills Physics Laboratory, University of Bristol, Bristol BS8 1TL, UK
- Present address: High Field Magnet Laboratory, Radboud University Nijmegen, The Netherlands
| | - B. Vignolle
- Laboratoire National des Champs Magnétiques Intenses, Toulouse 31400, France
| | - C. Proust
- Canadian Institute for Advanced Research, Toronto, Ontario, Canada M5G 1Z8
- Laboratoire National des Champs Magnétiques Intenses, Toulouse 31400, France
| | - M. Sutherland
- Cavendish Laboratory, University of Cambridge, Cambridge CB3 0HE, UK
| | - S. Krämer
- Laboratoire National des Champs Magnétiques Intenses, Grenoble, France
| | - J. -H. Park
- National High Magnetic Field Laboratory, Tallahassee, Florida 32310, USA
| | - D. Graf
- National High Magnetic Field Laboratory, Tallahassee, Florida 32310, USA
| | - N. Doiron-Leyraud
- Département de physique & RQMP, Université de Sherbrooke, Sherbrooke, Québec, Canada J1K 2R1
| | - Louis Taillefer
- Département de physique & RQMP, Université de Sherbrooke, Sherbrooke, Québec, Canada J1K 2R1
- Canadian Institute for Advanced Research, Toronto, Ontario, Canada M5G 1Z8
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Vekeman F, LaMori JC, Laliberté F, Nutescu E, Duh MS, Bookhart BK, Schein J, Dea K, Olson WH, Lefebvre P. In-hospital risk of venous thromboembolism and bleeding and associated costs for patients undergoing total hip or knee arthroplasty. J Med Econ 2012; 15:644-53. [PMID: 22356512 DOI: 10.3111/13696998.2012.669438] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [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: 11/09/2022]
Abstract
OBJECTIVE Benefits of anti-coagulation for venous thromboembolism (VTE) prevention in total hip and knee arthroplasty (THA/TKA) may be offset by increased risk of bleeding. The aim was to assess in-hospital risk of VTE and bleeding after THA/TKA and quantify any increased costs. METHODS Healthcare claims from the Premier Perspective(TM) Comparative Hospital Database (January 2000-September 2008) were selected for subjects ≥ 18 years with ≥ 1 diagnosis code for THA/TKA. VTE was defined as ≥ 1 code for deep vein thrombosis or pulmonary embolism. Bleeding was classified as major/non-major. Incremental in-hospital costs associated with VTE and bleeding were calculated as cost differences between inpatients with VTE or bleeding matched 1:1 with inpatients without VTE or bleeding. RESULTS A total of 820,197 inpatient stays were identified: 8042 had a VTE event and 7401 a bleeding event (2740 major bleeding). The risks of VTE, any bleeding, and major bleeding were 0.98, 0.90, and 0.33/100 inpatient stays, respectively. Mean incremental in-hospital costs per inpatient were $2663 for VTE, $2028 for bleeding, and $3198 for major bleeding. LIMITATIONS These included possible inaccuracies or omissions in procedures, diagnoses, or costs of claims data; no information on the amount of blood transfused or decreases in the hemoglobin level to evaluate bleeding event severity; and potential biases due to the observational design of the study. CONCLUSIONS In-hospital risk and incremental all-cause costs with THA/TKA were higher for VTE than for bleeding. Despite higher costs, major bleeding occurred less frequently than VTE, suggesting a favorable benefit/risk profile for VTE prophylaxis in THA/TKA.
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Affiliation(s)
- F Vekeman
- Groupe d’analyse, Ltée, Montréal, Québec, Canada
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15
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Chang J, Daou R, Proust C, Leboeuf D, Doiron-Leyraud N, Laliberté F, Pingault B, Ramshaw BJ, Liang R, Bonn DA, Hardy WN, Takagi H, Antunes AB, Sheikin I, Behnia K, Taillefer L. Nernst and Seebeck coefficients of the cuprate superconductor YBa2Cu3O6.67: a study of Fermi surface reconstruction. Phys Rev Lett 2010; 104:057005. [PMID: 20366789 DOI: 10.1103/physrevlett.104.057005] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/28/2009] [Indexed: 05/29/2023]
Abstract
The Seebeck and Nernst coefficients S and nu of the cuprate superconductor YBa{2}Cu{3}O{y} (YBCO) were measured in a single crystal with doping p=0.12 in magnetic fields up to H=28 T. Down to T=9 K, nu becomes independent of field by H approximately 30 T, showing that superconducting fluctuations have become negligible. In this field-induced normal state, S/T and nu/T are both large and negative in the T-->0 limit, with the magnitude and sign of S/T consistent with the small electronlike Fermi surface pocket detected previously by quantum oscillations and the Hall effect. The change of sign in S(T) at T approximately 50 K is remarkably similar to that observed in La2-xBaxCuO4, La{2-x-y}Nd{y}Sr_{x}CuO{4}, and La{2-x-y}Eu{y}Sr{x}CuO{4}, where it is clearly associated with the onset of stripe order. We propose that a similar density-wave mechanism causes the Fermi surface reconstruction in YBCO.
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Affiliation(s)
- J Chang
- Département de physique & RQMP, Université de Sherbrooke, Sherbrooke, Canada
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16
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Skarin AT, Vekeman F, Laliberté F, Afonja O, Lafeuille M, Barghout V, Duh MS. Pattern of utilization of pegfilgrastim in patients with chemotherapy-induced neutropenia: A retrospective analysis of administrative claims data. J Clin Oncol 2009. [DOI: 10.1200/jco.2009.27.15_suppl.9624] [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] [Indexed: 11/20/2022] Open
Abstract
9624 Background: Pegfilgrastim is a long-acting granulocyte colony-stimulating factor (G-CSF) used to prevent or treat febrile neutropenia associated with myelosuppressive anticancer therapies. According to the prescribing information, pegfilgrastim should not be administered within 14 days before or 24 hours after cytotoxic chemotherapy because of the potential for myeloid toxicity. This study examined use patterns of pegfilgrastim in real-life practice. Methods: Analysis of health insurance claims data in 2000- 2007 from > 35 large health plans across the US was conducted. Patients who had a cancer diagnosis and chemotherapy within 120 days of their first pegfilgrastim injection were identified. The proportion of pegfilgrastim injections that were followed by administration of chemotherapy within 11 and 9 days was calculated. Analysis was also stratified by cancer type [Non-Hodgkin's lymphoma (NHL), lung, breast]. Results: A total of 13,526 cancer patients received 57,118 pegfilgrastim injections. NHL, lung, and breast cohorts comprised 2,722, 2,772, and 4,955 patients, respectively. Mean age (SD) was 55.0 (11.6) and women represented 65.9% of study population. Among all cancer types, 19.2% of pegfilgrastim injections had a chemotherapy claim within the following 11 days. This pattern of use was the highest in NHL (18.9%), followed by lung (17.1%), and breast (16.2%). Similar results were observed in the 9-day sensitivity analysis (see Table ). Conclusions: Based on the retrospective analysis of this administrative claims database, the use of pegfilgrastim within 11 days of an administration of chemotherapy was observed in 15–20% of cases which is inconsistent with the recommended guidelines. Pegfilgrastim use in these situations may have the potential to increase sensitivity of rapidly dividing myeloid cells to cytotoxic chemotherapy. Further research is being conducted to assess the related clinical and economic impact of this pattern of usage. [Table: see text] [Table: see text]
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Affiliation(s)
- A. T. Skarin
- Dana-Farber Cancer Institute, Boston, MA; Groupe d'Analyse, Ltée, Montréal, QC, Canada; Bayer HealthCare Pharmaceuticals, Wayne, NJ; Analysis Group, Inc., Boston, MA
| | - F. Vekeman
- Dana-Farber Cancer Institute, Boston, MA; Groupe d'Analyse, Ltée, Montréal, QC, Canada; Bayer HealthCare Pharmaceuticals, Wayne, NJ; Analysis Group, Inc., Boston, MA
| | - F. Laliberté
- Dana-Farber Cancer Institute, Boston, MA; Groupe d'Analyse, Ltée, Montréal, QC, Canada; Bayer HealthCare Pharmaceuticals, Wayne, NJ; Analysis Group, Inc., Boston, MA
| | - O. Afonja
- Dana-Farber Cancer Institute, Boston, MA; Groupe d'Analyse, Ltée, Montréal, QC, Canada; Bayer HealthCare Pharmaceuticals, Wayne, NJ; Analysis Group, Inc., Boston, MA
| | - M. Lafeuille
- Dana-Farber Cancer Institute, Boston, MA; Groupe d'Analyse, Ltée, Montréal, QC, Canada; Bayer HealthCare Pharmaceuticals, Wayne, NJ; Analysis Group, Inc., Boston, MA
| | - V. Barghout
- Dana-Farber Cancer Institute, Boston, MA; Groupe d'Analyse, Ltée, Montréal, QC, Canada; Bayer HealthCare Pharmaceuticals, Wayne, NJ; Analysis Group, Inc., Boston, MA
| | - M. S. Duh
- Dana-Farber Cancer Institute, Boston, MA; Groupe d'Analyse, Ltée, Montréal, QC, Canada; Bayer HealthCare Pharmaceuticals, Wayne, NJ; Analysis Group, Inc., Boston, MA
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Cyr-Choinière O, Daou R, Laliberté F, LeBoeuf D, Doiron-Leyraud N, Chang J, Yan JQ, Cheng JG, Zhou JS, Goodenough JB, Pyon S, Takayama T, Takagi H, Tanaka Y, Taillefer L. Enhancement of the Nernst effect by stripe order in a high-Tc superconductor. Nature 2009; 458:743-5. [DOI: 10.1038/nature07931] [Citation(s) in RCA: 117] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2008] [Accepted: 02/23/2009] [Indexed: 11/09/2022]
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18
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Liu S, Laliberté F, Bobechko B, Bartlett A, Lario P, Gorseth E, Van Hamme J, Gresser MJ, Huang Z. Dissecting the cofactor-dependent and independent bindings of PDE4 inhibitors. Biochemistry 2001; 40:10179-86. [PMID: 11513595 DOI: 10.1021/bi010096p] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Type 4 phosphodiesterases (PDE4s) are metallohydrolases that catalyze the hydrolysis of cAMP to AMP. At the bottom of its active site lie two divalent metal ions in a binuclear motif which are involved in both cAMP binding and catalysis [(2000) Science 288, 1822-1825; (2000) Biochemistry 39, 6449-6458]. Using a SPA-based equilibrium [(3)H]rolipram binding assay, we have determined that Mg(2+), Mn(2+), and Co(2+) all mediated a high-affinity (K(d) between 3 and 8 nM) and near stoichiometric (R)-rolipram binding to PDE4. In their absence, (R)-rolipram binds stoichiometrically to the metal ion-free apoenzyme with a K(d) of approximately 150 nM. The divalent cation dose responses in mediating the high-affinity rolipram/PDE4 interaction mirror their efficacy in catalysis, suggesting that both metal ions of the holoenzyme are involved in mediating the high-affinity (R)-rolipram/PDE4 interaction. The specific rolipram binding to the apo- and holoenzyme is differentially displaced by cAMP, AMP, and other inhibitors, providing a robust tool to dissect the components of metal ion-dependent and independent PDE4/ligand interactions. cAMP binds to the holoenzyme with a K(s) of 1.9 microM and nonproductively to the apoenzyme with a K(d) of 179 microM. In comparison, AMP binds to the holo- and apoenzyme with K(d) values of 7 and 11 mM, respectively. The diminished Mg(2+)-dependent component of AMP binding to PDE4 suggests that most of the Mg(2+)/phosphate interaction in the cAMP/PDE4 complex is disrupted upon the hydrolysis of the cyclic phosphoester bond, leading to the rapid release of AMP.
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Affiliation(s)
- S Liu
- Department of Biochemistry and Molecular Biology, Merck Frosst Center for Therapeutical Research, P.O. Box 1005, Pointe Claire, Dorval, Quebec H9R 4P8, Canada
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19
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Klossek JM, Laliberté F, Laliberté MF, Mounedji N, Bousquet J. Local safety of intranasal triamcinolone acetonide: clinical and histological aspects of nasal mucosa in the long-term treatment of perennial allergic rhinitis. Rhinology 2001; 39:17-22. [PMID: 11340690] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/20/2023]
Abstract
Intranasal corticosteroids are increasingly used to treat allergic rhinitis and their long-term use is generally safe. However, the long-term safety of each molecule should be assessed. The main aim of this multicenter, prospective, randomized, open-label study was to evaluate the effect of triamcinolone acetonide aqueous intranasal spray on nasal mucosal thickness, macroscopic appearance, and mucociliary function. Patients with perennial allergic rhinitis were treated with triamcinolone acetonide 220 micrograms/day for six months. Nasal biopsies taken before and after treatment were compared with biopsies from patients who had been randomized to oral cetirizine 10 mg day or intranasal beclomethasone dipropionate 400 micrograms/day. In the evaluable population (n = 70), there were no significant differences between groups in terms of histologically evaluated thickness and endoscopically evaluated macroscopic appearance of the nasal mucosa, or indigocarmine saccharine test mucociliary function. In the intent-to-treat population (n = 92), there was no difference between treatment groups in the incidence of overall adverse events. This study indicates that sustained treatment with intranasal triamcinolone acetonide does not lead to atrophy of the nasal mucosa or impairment of mucociliary function.
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Affiliation(s)
- J M Klossek
- Hôpital Jean Bernard La Mileterie, Poitiers, France
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20
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Macdonald D, Perrier H, Liu S, Laliberté F, Rasori R, Robichaud A, Masson P, Huang Z. Hunting the emesis and efficacy targets of PDE4 inhibitors: identification of the photoaffinity probe 8-(3-azidophenyl)-6- [(4-iodo-1H-1-imidazolyl)methyl]quinoline (APIIMQ). J Med Chem 2000; 43:3820-3. [PMID: 11052785 DOI: 10.1021/jm000065c] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- D Macdonald
- Merck Frosst Centre for Therapeutic Research, P.O. Box 1005, Pointe Claire-Dorval, Québec, Canada, H9R 4P8.
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21
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Laliberté F, Laliberté MF, Lécart S, Bousquet J, Klossec JM, Mounedji N. Clinical and pathologic methods to assess the long-term safety of nasal corticosteroids. French Triamcinolone Acetonide Study Group. Allergy 2000; 55:718-22. [PMID: 10955697 DOI: 10.1034/j.1398-9995.2000.00649.x] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
BACKGROUND The main objective of this long-term prospective local safety study was to evaluate endoscopic and histologic changes in nasal epithelium after 6-month treatment with triamcinolone acetonide (TAA). We describe here a method to measure quantitatively epithelium thickness. Results were compared with those seen with the use of cetirizine (an antihistamine) and another oral intranasal corticosteroid, beclomethasone dipropionate (BDP). METHODS Patients were examined by an ENT specialist who first performed an endoscopic evaluation of the nasal cavities, assessing any morphologic abnormalities and the aspect of the mucosa. Biopsies were taken from the inferior turbinate before and after 24 weeks of treatment. Biopsies were immediately fixed in cold acetone (-20 degrees C) and embedded in glycolmethacrylate; sections of 2 microm were cut on an ultramicrotome. Morphometric evaluations were done in a blinded fashion by computerized image analysis to measure an epithelial area over a minimum length of 50 microm. The thickness was ascertained by the ratio of area to length. RESULTS 1) For all three treatment groups, the nasal epithelium thickness decreased slightly from pretreatment to the end of treatment. 2) No statistically significant differences between the three treatment groups were found in epithelium thickness. 3) Macroscopically, nasal tissues in all treated groups were normal. CONCLUSIONS These results clearly indicate that long-term treatment with TAA has no atrophic effect on nasal mucosa.
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Affiliation(s)
- F Laliberté
- Unité 454 de l'INSERM, Hôpital A. de Villeneuve, Montpellier, France
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22
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Laliberté F, Han Y, Govindarajan A, Giroux A, Liu S, Bobechko B, Lario P, Bartlett A, Gorseth E, Gresser M, Huang Z. Conformational difference between PDE4 apoenzyme and holoenzyme. Biochemistry 2000; 39:6449-58. [PMID: 10828959 DOI: 10.1021/bi992432w] [Citation(s) in RCA: 70] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The type 4 cAMP-specific phosphodiesterases (PDE4s) are Mg(2+)-dependent hydrolases that catalyze the hydrolysis of 3', 5'-cAMP to AMP. Previous studies indicate that PDE4 exists in two conformations that bind the inhibitor rolipram with affinities differing by more than 100-fold. Here we report that these two conformations are the consequence of PDE4 binding to its metal cofactor such as Mg(2+). Using a fluorescence resonance energy transfer (FRET)-based equilibrium binding assay, we identified that L-791,760, a fluorescent inhibitor, binds to the apoenzyme (free enzyme) and the holoenzyme (enzyme bound to Mg(2+)) with comparable affinities (K(d) approximately 30 nM). By measuring the displacement of the bound L-791,760, we have also identified that other inhibitors bind differentially with the apoenzyme and the holoenzyme depending upon their structure. CDP-840, SB-207499, and RP-73401 bind preferentially to the holoenzyme. The conformational-sensitive inhibitor (R)-rolipram binds to the holoenzyme and apoenzyme with affinities (K(d)) of 5 and 300 nM, respectively. In contrast to its high affinity (K(d) approximately 2 microM) and active holoenzyme complex, cAMP binds to the apoenzyme nonproductively with a reduced affinity (K(d) approximately 170 microM). These results demonstrate that cofactor binding to PDE4 is responsible for eliciting its high-affinity interaction with cAMP and the activation of catalysis.
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Affiliation(s)
- F Laliberté
- Department of Biochemistry and Molecular Biology, Merck Frosst Centre for Therapeutic Research, Pointe Claire-Dorval, Quebec, H9R 4P8, Canada
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23
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Abstract
The synthesis and in vitro activity of a series of substituted furans as a novel structural class of PDE4 inhibitors is described. Comparison of emetic threshold with known PDE4 inhibitors is presented.
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Affiliation(s)
- H Perrier
- Merck Frosst Centre for Therapeutic Research, Pointe Claire-Dorval, Québec, Canada
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24
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Mathieu MN, Vittet D, Laliberté MF, Laliberté F, Nonotte I, Hamroun D, Launay JM, Chevillard C. Endothelin expression in human megakaryoblastic leukemia cell lines and normal platelet precursors. Regul Pept 1997; 68:91-7. [PMID: 9110379 DOI: 10.1016/s0167-0115(96)02108-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The aim of the present investigation was to determine whether endothelin (ET) could be expressed in and released from the human leukemia megakaryoblastic cell lines HEL, MEG-01, DAMI and the normal human platelet progenitors. Using the reverse transcriptase-polymerase chain reaction (RT-PCR) on total RNA isolated from the cells, we amplified a cDNA of the expected size (453 bp). Southern-blotting hybridization revealed that RT-PCR products from the cell lines were specific of ET-1 mRNA. Immunocytochemical analyses highlighted immunoreactive ET-1 in the cytoplasm of these cells which also released the mature peptide. ET-1 release from the three cell lines was increased by thrombin exposure. Although MEG-01 cells express ET receptors, ET-1, the selective ETB agonist sarafotoxin 6C and the non-selective ET-receptor antagonist PD 142893 showed no proliferative or antiproliferative action in basal or stimulating medium. This indicated a lack of autocrine ET-mediated effect on growth. These results demonstrate for the first time that human megakaryoblastic leukemia cell lines and normal bone marrow platelet precursors express ET-1 mRNA and release the mature peptide.
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Affiliation(s)
- M N Mathieu
- INSERM U 300, Faculté de Pharmacie, Montpellier, France
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25
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Bayburt T, Yu BZ, Street I, Ghomashchi F, Laliberté F, Perrier H, Wang Z, Homan R, Jain MK, Gelb MH. Continuous, vesicle-based fluorimetric assays of 14- and 85-kDa phospholipases A2. Anal Biochem 1995; 232:7-23. [PMID: 8600835 DOI: 10.1006/abio.1995.9967] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
This paper describes the synthesis and analysis of new substrates for the 85-kDa, mammalian, cytosolic phospholipase A2 (cPLA2) and the 14-kDa, human nonpancreatic, secreted phospholipase A2 (sPLA2). Phosphatidylcholines containing an arachidonyl chain at the sn-2 position and either a 10-pyrenedecyl or a 10-pyrenedecanoyl chain at the sn-1 position were synthesized and shown to be substrates for cPLA2 in a fluorescence-based assay. Most of the assays make use of small and large unilamellar vesicles of substrate phospholipid, although the assay also works when the substrate is dispersed in Triton X-100 mixed-micelles. The cPLA2 assays can be carried out in a fixed time-point mode in which one of the products, the pyrene-containing lysophospholipid, is detected by rapid HPLC. Alternatively, the assay becomes continuous when bovine serum albumin is present in the aqueous phase; this protein extracts the pyrene-containing lysophospholipid from the vesicle, and this leads to the fluorescence of monomeric pyrene label. These assays are capable of detecting subnanogram amounts of cPLA2. The ester formed between gamma-linolenic acid and 7-hydroxycoumarin is also a substrate for cPLA2, and when incorporated into vesicles of the anionic phospholipid, 1,2-dioleoyl-sn-glycero-3-phosphomethanol, provides an assay in which the enzyme does not leave the vesicle surface (scooting mode). Unlike all of the previously reported, vesicle-based cPLA2 assays, a prolonged linear reaction progress is seen with the DOPM-based assay. An assay of sPLA2 with subnanogram sensitivity was developed which makes use of the substrate 1-palmitoyl-2-(10-pyrenedecanoyl)-sn-glycero-3-phosphomethanol and a lipid sink. The latter is composed of phosphatidylcholine vesicles, in excess of substrate vesicles, which do not bind sPLA2 but provide a trap for enzyme-produced 10-pyrenedecanoic acid. The fluorescence of monomeric pyrene label in sink vesicles is detected. A second sPLA2 assay using a single type of vesicle was developed based on the substrate 1,2-di(10-pyrenedecanoyl)-sn-glycero-3-phosphocholine present at 10 mol% in vesicles of the nonhydrolyzable anionic phospholipid 1,2-ditetradecyl-sn-glycero-3-phosphomethanol. The action of sPLA2 on this fluorescent substrate leads to a separation of the pyrene chains resulting in fluorescence emission from monomeric pyrene. These cPLA2 and sPLA2 assays are ideal for inhibitor screening and analysis, and for studying the interfacial kinetics of these enzymes.
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Affiliation(s)
- T Bayburt
- Department of Chemistry, University of Washington, Seattle 98195-1700, USA
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26
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Nonotte I, Laliberté MF, Rémy-Heintz N, Laliberté F, Chevillard C. Expression of angiotensin I-converting enzyme in the human gastric HGT-1 cell line. Regul Pept 1995; 59:379-87. [PMID: 8577943 DOI: 10.1016/0167-0115(95)00090-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
We have previously shown that angiotensin I-converting enzyme (ACE) was expressed by epithelial cells of the rabbit gastric mucosa. In a search to obtain a cell model to study the regulation of ACE expression of gastric origin and its relationship with gastrin-cholecystokinin peptides, which have been proposed as ACE substrates, we investigated whether the HGT-1 human gastric cell line, which expresses gastrin, could also express ACE, using enzymatic and immunodetection methods as well as Northern-blot analysis and polymerase chain reaction. Results show that HGT-1 cells expressed a protein with a molecular weight of 130-140 kDa whose enzymatic and immunological properties were identical to those of ACE. More than 80% of ACE activity was found to be ectoenzymatic. However, immunocytochemical localization has mainly shown an intracellular localization, suggesting that most of intracytoplasmic ACE was not enzymatically active. In addition, Northern-blot analysis and polymerase chain reaction showed that the mRNA encoding that protein displayed a size and a sequence identical to those of somatic ACE. It therefore appears that the HGT-1 cell line could be a useful model to study both the regulation of gastric ACE and its interactions with gastrin-cholecystokinin peptides.
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Affiliation(s)
- I Nonotte
- INSERM U. 300, Faculté de Pharmacie, Montpellier, France
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27
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Abdullah K, Cromlish WA, Payette P, Laliberté F, Huang Z, Street I, Kennedy BP. Human cytosolic phospholipase A2 expressed in insect cells is extensively phosphorylated on Ser-505. Biochim Biophys Acta 1995; 1244:157-64. [PMID: 7766652 DOI: 10.1016/0304-4165(94)00218-m] [Citation(s) in RCA: 23] [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] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Cytosolic PLA2 (cPLA2) has been implicated in the release of the arachidonic acid utilized in the inflammatory cascade. Phosphorylation of cPLA2 on Ser-505 by MAP kinase in response to agonist treatment, is thought to be one of the mechanisms required for activation of the enzyme in the cell. In order to obtain enough material for enzymological studies as well as to investigate the role of phosphorylation in the activation of cPLA2, the human enzyme was overexpressed in insect cells using a recombinant baculovirus. We report here on the characterization of the phosphorylation state of cPLA2 overexpressed in Sf9 cells. The level of overexpressed cPLA2 was shown to peak between 48 and 60 h post-infection, by this time the phosphorylated enzyme could easily be detected because of its reduced mobility on polyacrylamide gels. The reduced mobility or gel-shift has been shown to be due to phosphorylation of Ser-505. To determine whether this was also the case for insect cell overexpressed cPLA2, Ser-505 was replaced by Ala, and this mutant (cPLA2S505A) was expressed in Sf9 cells. Analysis of the overexpressed cPLA2S505A showed that it migrated only as the lower unshifted cPLA2 band confirming that the baculovirus overexpressed cPLA2 is extensively phosphorylated on Ser-505. Furthermore, treatment of infected Sf9 cells expressing the wild-type cPLA2 with phorbol 12-tetradecanoate 13-acetate (TPA) shifted all of the overexpressed cPLA2 to the phosphorylated Ser-505 form. When infected Sf9 cells were labelled with [32P], in addition to labelling of Ser-505 other sites were also labelled. Both cPLA2 and cPLA2S505A were purified from infected Sf9 cells and the specific activity for each of the enzymes was measured in a phosphatidylcholine vesicle fluorescence assay using 1-(10-pyrenedecanyl)arachidonyl-sn-glycero-3-phosphocholine as substrate. Under these conditions the specific activity of cPLA2 was, 2 mumol/min per mg, whereas cPLA2S505A was 7-fold less active. These findings suggest that Sf9 cells have a mechanism for phosphorylating cPLA2 similar to that found in mammalian cells which probably proceeds through a MAP kinase. Thus, insect cell overexpressed cPLA2 is a very good source for the Ser-505 phosphorylated enzyme.
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Affiliation(s)
- K Abdullah
- Department of Biochemistry and Molecular Biology, Merck Frosst Center for Therapeutic Research, Merck Frosst Canada Inc., Pointe Claire-Dorval, Quebec
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28
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Huang Z, Laliberté F, Tremblay NM, Weech PK, Street IP. A continuous fluorescence-based assay for the human high-molecular-weight cytosolic phospholipase A2. Anal Biochem 1994; 222:110-5. [PMID: 7856835 DOI: 10.1006/abio.1994.1461] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.2] [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: 01/27/2023]
Abstract
A sensitive method for continuously monitoring the activity of the human cytosolic phospholipase A2 (cPLA2) is described. Recombinant cPLA2 efficiently hydrolyzes fatty acid esters of 7-hydroxycoumarin, producing the free fatty acid and the highly fluorescent 7-hydroxycoumarin. All of the observed 7-hydroxycoumarinyl ester hydrolase activity (7-HCEase) in a preparation of the purified recombinant cPLA2 was due to this enzyme since: (1) all of the ester hydrolase activity comigrated on nondenaturing polyacrylamide gel with a protein characterized as the cPLA2 by Western analysis; (2) the immunoreactive protein also possessed both phospholipase A2 and lysophospholipase activities; and (3) arachidonyl trifluoromethyl ketone, a potent inhibitor of the phospholipase A2 activity of cPLA2, also inhibited the 7-HCEase activity. A study of the 7-HCEase activity demonstrated that when 7-hydroxycoumarinyl gamma-linolenate was dispersed in a phospholipid matrix it was hydrolyzed by cPLA2 at a rate comparable to that of an arachidonyl-containing phospholipid substrate and with an identical reaction progress curve. In the presence of phospholipid vesicles, the cPLA2-catalyzed hydrolysis of hydrophobic 7-hydroxycoumarinyl esters was stimulated by submicromolar concentration of free calcium and showed a preference for polyunsaturated substrates. The cPLA2-catalyzed hydrolysis of the water-soluble substrate 7-hydroxycoumarinyl 6-heptenoate was catalyzed by cPLA2 in the absence of calcium and other lipids.
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Affiliation(s)
- Z Huang
- Department of Biochemistry and Molecular Biology, Merck Forsst Centre for Therapeutic Research, Pointe Claire-Dorval, Quebec, Canada
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29
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Riendeau D, Guay J, Weech PK, Laliberté F, Yergey J, Li C, Desmarais S, Perrier H, Liu S, Nicoll-Griffith D. Arachidonyl trifluoromethyl ketone, a potent inhibitor of 85-kDa phospholipase A2, blocks production of arachidonate and 12-hydroxyeicosatetraenoic acid by calcium ionophore-challenged platelets. J Biol Chem 1994; 269:15619-24. [PMID: 8195210] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
Arachidonyl trifluoromethyl ketone (AACOCF3) is a potent and selective slow binding inhibitor of the 85-kDa cytosolic phospholipase A2 (cPLA2) (Street, I. P., Lin, H.-K., Laliberté, F., Ghomashchi, F., Wang, Z., Perrier, H., Tremblay, N. M., Huang, Z., Weech, P. K., and Gelb, M. H. (1993) Biochemistry 32, 5935-5940). AACOCF3 and a number of its structural analogues have been used to investigate the role of cPLA2 in the cellular generation of free arachidonic acid (AA) and in eicosanoid biosynthesis. AACOCF3 inhibited the release of AA from calcium ionophore-challenged U937 cells (IC50 = 8 microM, 2 x 10(6) cells ml-1) and from platelets (IC50 = 2 microM, 4 x 10(7) cells ml-1). Arachidonyl methyl ketone (AACOCH3) and AACH(OH)CF3, both of which are noninhibitory to the purified cPLA2, did not inhibit the production of AA in the ionophore-challenged cells. In addition to the release of AA, AACOCF3 also inhibited the production of 12-hydroxyeicosatetraenoic acid (12-HETE) and thromboxane B2, two of the major metabolites of AA produced by platelets. The inhibition of 12-HETE biosynthesis showed a dose dependence similar to that of AA release in ionophore-challenged platelets; however, when platelet 12-HETE production was stimulated with 10 microM AA to circumvent the PLA2-dependent step, AACOCF3 no longer inhibited the production of 12-HETE. In contrast, AACOCF3 blocked thromboxane B2 formation by both calcium ionophore- and AA-challenged platelets, indicating that the compound affects the cyclooxygenase pathway in addition to AA release. The crude cytosol and membrane fractions from platelets were assayed for calcium-dependent and calcium-independent PLA2 activities and for the susceptibility of each to inhibition by AACOCF3. At AACOCF3 concentrations as high as 10 mol %, only one of the observed PLA2 activities was inhibited by more than 25%. The AACOCF3-susceptible PLA2 (77% inhibition at 1.6 mol %) was found in the cytosolic platelet fraction and showed the functional characteristics of the cPLA2. These results suggest that the cPLA2 plays an important role in the generation of free AA for 12-HETE biosynthesis in platelets.
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Affiliation(s)
- D Riendeau
- Department of Biochemistry and Molecular Biology, Merck Frosst Centre for Therapeutic Research, Pointe Claire-Dorval, Quebec, Canada
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30
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Riendeau D, Guay J, Weech P, Laliberté F, Yergey J, Li C, Desmarais S, Perrier H, Liu S, Nicoll-Griffith D. Arachidonyl trifluoromethyl ketone, a potent inhibitor of 85-kDa phospholipase A2, blocks production of arachidonate and 12-hydroxyeicosatetraenoic acid by calcium ionophore-challenged platelets. J Biol Chem 1994. [DOI: 10.1016/s0021-9258(17)40726-5] [Citation(s) in RCA: 203] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
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31
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Nonotte I, Laliberté MF, Gannoun-Zaki L, Bali JP, Chevillard C, Laliberté F. Localization of angiotensin-converting enzyme (ACE) mRNA in rabbit gastric mucosa by in situ hybridization. J Histochem Cytochem 1994; 42:197-201. [PMID: 8288865 DOI: 10.1177/42.2.8288865] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [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
In a previous study we showed, by immunohistochemical analysis on rabbit fundic mucosa, that in addition to its usual presence on the luminal plasma membrane of endothelial cells, angiotensin converting-enzyme (ACE) was localized inside granules of surface and neck mucous cells and within granules of chief cells. The aim of the present study was to localize ACE mRNA in cells of the rabbit fundic mucosa by in situ hybridization with a 35S-labeled probe. This probe was a cDNA fragment (406 BP) encoding a portion of the rabbit ACE mRNA obtained by reverse transcription followed by polymerase chain reaction on total RNA extracted from fundic mucosa. ACE mRNAs were detected in mucous and chief cells and in endothelial cells of the mucosal vasculature. These results are in complete agreement with our prior studies which showed by immunohistochemical analysis that ACE is present in these cells. Our findings therefore suggest that ACE previously detected in epithelial cells of the rabbit gastric mucosa is actually synthesized within these cells.
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Affiliation(s)
- I Nonotte
- INSERM U.300, Faculté de Pharmacie, Montpellier, France
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32
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Tremblay NM, Kennedy BP, Street IP, Kaupp WJ, Laliberté F, Weech PK. Human group II phospholipase A2 expressed in Trichoplusia ni larvae--isolation and kinetic properties of the enzyme. Protein Expr Purif 1993; 4:490-8. [PMID: 8251761 DOI: 10.1006/prep.1993.1064] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Human secreted synovial fluid/platelet-type group II phospholipase A2 (sPLA2) was expressed in Trichoplusia ni (cabbage looper) larvae and cultured Sf9 insect cells by infection with a recombinant baculovirus. Active sPLA2, with correct N-terminal proteolytic processing, was not secreted by Sf9 cells in culture. The enzyme was isolated from their homogenate without any need for refolding or renaturation of the protein. The enzyme was extracted from the 5000g pellet with 1 M KBr and isolated by chromatography on a cation exchange column followed by reverse-phase chromatography on a Butyl Aquapore column. The yield of active enzyme (25 micrograms/g insect) was comparable to yields obtained in CHO cells or Escherichia coli by other investigators. The recombinant enzyme had the correct N-terminal sequence, expected molecular weight, and reacted with antisera raised against peptides inferred from the cDNA sequence of the natural enzyme. Monoclonal antibodies were raised against the recombinant sPLA2 and they permitted the isolation of the natural enzyme from human serum by immunoaffinity. The recombinant sPLA2 showed a preference for substrate vesicles with a net negative charge. The baculovirus expression system provided active sPLA2 that can be produced economically in insects, purified simply, had well-defined kinetic properties, and should be useful in studies of inflammatory disorders.
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Affiliation(s)
- N M Tremblay
- Merck Frosst Centre for Therapeutic Research, Merck Frosst Canada, Inc., Dorval, Québec
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33
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Street IP, Lin HK, Laliberté F, Ghomashchi F, Wang Z, Perrier H, Tremblay NM, Huang Z, Weech PK, Gelb MH. Slow- and tight-binding inhibitors of the 85-kDa human phospholipase A2. Biochemistry 1993; 32:5935-40. [PMID: 8018213 DOI: 10.1021/bi00074a003] [Citation(s) in RCA: 361] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
A trifluoromethyl ketone analogue of arachidonic acid in which the COOH group is replaced with COCF3 (AACOCF3) was prepared and found to be a tight- and slow-binding inhibitor of the 85-kDa cytosolic human phospholipase A2 (cPLA2). Enzyme inhibition was observed when AACOCF3 was tested in assays using either phospholipid vesicles or phospholipid/Triton X-100 mixed micelles. The fact that the inhibition developed over several minutes in both assays establishes that AACOCF3 inhibits by direct binding to the enzyme rather than by decreasing the fraction of enzyme bound to the substrate interface. From the measured values of the inhibitor association and dissociation rate constants, an upper limit of the equilibrium dissociation constant for the Ca(2+).AACOCF3.PLA2 complex of 5 x 10(-5) mole fraction was obtained. Thus, detectable inhibition of cPLA2 by AACOCF3 occurs when this compound is present in the assay at a level of one inhibitor per several thousand substrates. Arachidonic acid analogues in which the COOH group is replaced by COCH3, CH(OH)CF3, CHO, or CONH2 did not detectably inhibit the cPLA2. The arachidonyl ketones AACOCF2CF3 and AACOCF2Cl were found by 19F NMR to be less hydrated than AACOCF3 in phospholipid/Triton X-100 mixed micelles, and compared to AACOCF3 these compounds are also weaker inhibitors of cPLA2. In keeping with the fact that cPLA2 displays substrate specificity for arachidonyl-containing phospholipids, the arachidic acid analogue C19H39COCF3 is a considerably less potent inhibitor compared to AACOCF3.(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- I P Street
- Merck Frosst Centre for Therapeutic Research, Pointe Claire-Dorval, Québec, Canada
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34
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Nonotte I, Laliberté MF, Duperray C, Hollande F, Bali JP, Laliberté F, Chevillard C. Expression of angiotensin I converting enzyme mRNA in rabbit gastric epithelial cells. Mol Cell Endocrinol 1993; 92:167-74. [PMID: 8391487 DOI: 10.1016/0303-7207(93)90004-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [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: 01/30/2023]
Abstract
Angiotensin I converting enzyme (ACE) is a dipeptidyl carboxypeptidase synthesized by endothelial cells from many vascular beds as well as by extravascular tissues. Two forms of ACE have been characterized, a pulmonary form and a testicular form. Previously, in the gastrointestinal tract, we localized ACE in the rabbit gastric fundic tissue. In the present study, Northern blot analysis demonstrated the expression of a 5 kb ACE mRNA in fundic mucosa, identical in size to pulmonary ACE mRNA. In order to confirm the epithelial origin of this ACE, we have purified fundic epithelial cells by a flow cytometry technique by which endothelial cells were excluded and the population was enriched in intermediate and chief cells. Using reverse transcription and polymerase chain reaction with specific oligonucleotides, we have amplified from the enriched fundic epithelial cell RNA a 874 bp fragment, the restriction map of which is identical to that of rabbit lung. These findings demonstrate that in gastric mucosa ACE is expressed in fundic epithelial cells and seems to be similar to the pulmonary form.
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Affiliation(s)
- I Nonotte
- INSERM U. 300, Faculté de Pharmacie, Montpellier, France
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35
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Riendeau D, Falgueyret JP, Meisner D, Sherman MM, Laliberté F, Street IP. Interfacial catalysis and production of a high ratio of leukotriene A4 to 5-HPETE by 5-lipoxygenase in a coupled assay with phospholipase A2. J Lipid Mediat 1993; 6:23-30. [PMID: 8395245] [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: 01/30/2023]
Abstract
The activity of purified 5-lipoxygenases (5-LO) shows a requirement for the presence of phosphatidylcholine or other lipids, in addition to Ca2+ and ATP. The enzymatic activity of purified human 5-lipoxygenase was dependent on the ratio of arachidonic acid to phospholipids rather than on the bulk arachidonic acid concentration, suggesting that the concentration of substrate at the lipid-water interface is important for the rate of the 5-LO reaction. Enzyme activity was also examined using vesicles of dimyristoylphosphatidylmethanol/1-palmitoyl-2-arachidonoylphosp hat idylcholine. Using PLA2 to release arachidonic acid from phospholipid, the ratio of leukotriene A4 (detected as trans-LTB4 isomers) to 5-hydroperoxyeicosatetraenoic acid (5-HPETE) accumulated depended on the 5-LO concentration and was relatively independent of the amount of PLA2. The ratio of leukotriene A4 to 5-HPETE production increased with the amount of 5-LO (1-15 micrograms/ml) to reach values (> 10) similar to those observed with ionophore-challenged human leukocytes. The data are consistent with the catalysis of 5-LO occurring at the surface of phospholipid vesicles with the 5-HPETE product being re-utilized by the LTA4 synthase reaction of 5-lipoxygenase under conditions of limiting arachidonic acid availability.
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Affiliation(s)
- D Riendeau
- Biochemistry Department, Merck Frosst Canada Inc., Pointe Claire-Dorval, Québec
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36
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Laliberté F, Laliberté MF, Nonotte I, Bali JP, Chevillard C. Angiotensin I converting enzyme in gastric mucosa of the rabbit: localization by autoradiography, immunofluorescence, and immunoelectron microscopy. J Histochem Cytochem 1991; 39:1519-29. [PMID: 1655876 DOI: 10.1177/39.11.1655876] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
To localize angiotensin converting enzyme (ACE) in the fundic mucosa of the rabbit, we used autoradiography with the ACE inhibitor [3H]-trandolaprilate and post-embedding immunocytochemical techniques with a goat anti-rabbit ACE, using fluorescence and electron microscopy. Autoradiographic localization of [3H]-trandolaprilate in rabbit fundus sections shows that ACE is present in the fundic mucosa and mainly in the gland area. Fundic mucosa was fixed with 4% formaldehyde and embedded in Lowicryl K4M. Semi-thin (1 micron) or thin sections (800-900 A) were stained with anti-rabbit ACE followed by fluorescein isothyocyanate-labeled rabbit anti-goat IgG or protein A-gold reagent, respectively. Label was present on endothelium of all blood vessels running through the mucosa. Label was prominently localized in the granules of mucous surface and neck cells and on the granules of chief cells. The intracellular localization of ACE, and particularly its intragranular presence within chief and mucous cells, suggests that the enzyme, at the fundic level, is involved in the intragranular processing of a peptide, the nature of which remains to be determined.
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Affiliation(s)
- F Laliberté
- INSERM U.300, Faculté de Pharmacie, Montpellier, France
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37
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Tessier DC, Thomas DY, Khouri HE, Laliberté F, Vernet T. Enhanced secretion from insect cells of a foreign protein fused to the honeybee melittin signal peptide. Gene 1991; 98:177-83. [PMID: 2016060 DOI: 10.1016/0378-1119(91)90171-7] [Citation(s) in RCA: 217] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
The baculovirus/insect cell system has been remarkably successful in yielding high levels of synthesis of many proteins which have been difficult to synthesize in other host/vector systems. The system is also capable of secreting heterologous proteins, but with generally low efficiency. We have increased the efficiency of secretion of the system by using signal peptides of insect origin to direct the secretion of a foreign protein. The precursor of the plant cysteine protease papain (propapain) has been used as a report enzyme to compare secretion efficiency. Insect cells infected with a baculovirus recombined with the gene encoding propapain fused to the sequence encoding the honeybee melittin signal peptide secreted over five times more papain precursor than the wild-type prepropapain which used the plant signal peptide. Based on these results, we have assembled pVT-Bac, an Autographa californica nuclear polyhedrosis virus transfer vector that may enhance secretion of other foreign proteins from insect cells. The vector incorporates a number of features: phage f1 ori to facilitate site-directed mutagenesis, the strong polyhedrin promoter upstream from the melittin signal peptide-encoding sequence, and eight unique restriction sites to facilitate fusion of heterologous genes.
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Affiliation(s)
- D C Tessier
- Genetic Engineering Section, National Research Council of Canada, Montréal Québec
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38
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Vernet T, Tessier DC, Richardson C, Laliberté F, Khouri HE, Bell AW, Storer AC, Thomas DY. Secretion of functional papain precursor from insect cells. Requirement for N-glycosylation of the pro-region. J Biol Chem 1990; 265:16661-6. [PMID: 2204628] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
The synthetic gene coding for the precursor of the cysteine protease papain (EC 3.4.22.2) has been expressed using the baculovirus/insect cell system. The prepropapain gene was cloned into the transfer vector IpDC125 behind the polyhedrin promoter. The recombinant construct was then incorporated by homologous recombination into the Autographa californiaca nuclear polyhedrosis virus genome. The host Spodoptera frugiperda Sf9 cells infected with the recombinant baculovirus secrete an enzymatically inactive N-glycosylated papain precursor. This zymogen could be activated in vitro to yield about 400 nmol of active papain per liter of culture. The recombinant active mature papain was enzymatically indistinguishable from natural papain but the precursor was not processed to the same amino acid residue. The insect cells also accumulated prepropapain and glycosylated propapain intracellularly. This accumulation was an indication that there are rate-limiting steps in the secretion of proteins from insect cells in this expression system. Characterization of mutants of the precursor has shown that entry into the secretory pathway and addition of carbohydrate are prerequisite conditions for the production and secretion of functional propapain.
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Affiliation(s)
- T Vernet
- Genetic Engineering Section, National Research Council of Canada, Montreal, Quebec
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39
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Chevillard C, Brown NL, Jouquey S, Mathieu MN, Laliberté F, Hamon G. Cardiovascular actions and tissue-converting enzyme inhibitory effects of chronic enalapril and trandolapril treatment of spontaneously hypertensive rats. J Cardiovasc Pharmacol 1989; 14:297-301. [PMID: 2476605 DOI: 10.1097/00005344-198908000-00017] [Citation(s) in RCA: 19] [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] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The angiotensin I-converting enzyme (CE) inhibitors, trandolapril (RU 44570) and enalapril were administered for 2 weeks to SHR at doses (3 and 10 mg/kg/day, p.o., respectively) that produced important and comparable inhibitions of plasma (84 and 88%), aorta (97 and 88%), and atrium (89 and 82%) CE activities. At these doses, the inhibitory effects of trandolapril and enalapril were nonetheless different on CE in heart ventricle (58 and 72%) and kidney (45 and 85%). In addition, although both drugs reduced blood pressure (BP) and heart hypertrophy, trandolapril was more potent despite a lower dose-ratio. All these parameters were reexamined 1, 3, and 8 days after drug withdrawal: BP returned to control levels within 3 days in enalapril-treated rats, whereas it remained low for at least 8 days in trandolapril-treated animals. The reduction of heart hypertrophy owing to trandolapril was still present 8 days after drug discontinuation. On cessation of treatment, plasma CE increased above controls, ventricle CE returned to control levels within 3 days, whereas atrial and aortic CE activities remained inhibited for 8 days in the enalapril group. In contrast, in trandolapril-treated rats, CE activities in serum and tissues were still inhibited after 8 days. These results demonstrate that at the doses used trandolapril is more potent and longer acting than enalapril.
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Affiliation(s)
- C Chevillard
- INSERM U.300, Faculté de Pharmacie, Montpellier, France
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40
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Laliberté F, Laliberté MF, Alhenc-Gelas F, Chevillard C. Angiotensin converting enzyme (ACE) in iris vessels. An ultrastructural study. Exp Eye Res 1989; 49:153-7. [PMID: 2547643 DOI: 10.1016/0014-4835(89)90084-5] [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] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Affiliation(s)
- F Laliberté
- INSERM U.300, Faculte de Pharmacie, Montpellier, Paris, France
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41
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Vernet T, Tessier DC, Laliberté F, Dignard D, Thomas DY. The expression in Escherichia coli of a synthetic gene coding for the precursor of papain is prevented by its own putative signal sequence. Gene 1989; 77:229-36. [PMID: 2666263 DOI: 10.1016/0378-1119(89)90071-1] [Citation(s) in RCA: 32] [Impact Index Per Article: 0.9] [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: 01/02/2023]
Abstract
A 1048-bp gene coding for prepropapain was assembled from chemically synthesized oligodeoxyribonucleotides and cloned into a variety of Escherichia coli expression plasmids. We observed loss of plasmid when the preproP gene was expressed in E. coli either as the native precursor or fused at the C terminus of the first 592 amino acids (aa) of beta-galactosidase (beta Gal). Deletion of the putative 26-aa signal peptide (pre-region) increased plasmid stability. The level of maintenance for the different plasmid constructs correlated with the level of expression detected by immunoblotting. Constitutive expression of the beta Gal-propapain fusion generated insoluble granules in a protease-deficient E. coli host. The fusion protein was easily purified to near homogeneity by differential solubilization of the granules.
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Affiliation(s)
- T Vernet
- Biotechnology Research Institute, National Research Council of Canada, Montréal, Québec
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42
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Abstract
Pro-opiomelanocortin (POMC) is the precursor to several pituitary hormones including adrenocorticotropic hormone and beta-endorphin (beta-END). POMC is also expressed in the brain, predominantly in discrete neuronal cell populations of the hypothalamus. In the pituitary and brain, POMC undergoes tissue-specific proteolysis to release different bioactive peptides. POMC processing in neuronal cell lines was studied after infection of PC12 and Neuro2A cells with a recombinant retrovirus carrying the porcine POMC cDNA. Our results indicate that both cell lines synthesize and target POMC to the regulated secretory pathway. Only the Neuro2A cells, however, can achieve proteolytic processing of POMC. Chromatographic and immunological characterization of the POMC-related material showed that beta-lipotropin (beta-LPH) and nonacetylated beta-END(1-31) are major maturation products of POMC in these cells. Release of both beta-LPH and beta-END(1-31) from infected Neuro2A cells can be stimulated by secretagogues in a calcium-dependent manner. Taken together, our results suggest that the cellular machinery of Neuro2A cells can recognize a foreign prohormone, target it to neurosecretory vesicles, process it into biologically active peptides, and secrete it in a manner characteristic to peptidergic neurons.
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Affiliation(s)
- G Noël
- Département de Biochimie, Faculté de Médecine, Université de Montréal, Québec, Canada
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43
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Chevillard C, Brown NL, Mathieu MN, Laliberté F, Worcel M. Differential effects of oral trandolapril and enalapril on rat tissue angiotensin-converting enzyme. Eur J Pharmacol 1988; 147:23-8. [PMID: 2836219 DOI: 10.1016/0014-2999(88)90629-2] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Trandolapril (3-100 micrograms/kg) and enalapril (10-300 micrograms/kg) were administered orally to conscious rats. Angiotensin-converting enzyme (CE) activity was inhibited in serum, heart ventricle, renal inner cortex, lung, aorta, adrenal cortex and adrenal medulla, but not in the striatum. Inhibition was maximal at 2 h and with trandolapril was maintained for 24 h. Blood pressure and heart rate were not affected by either compound. Trandolapril was 6-10-fold more potent than enalapril. Differences between trandolapril and enalapril in CE inhibition observed in heart ventricle, adrenal cortex and medulla could be due to the presence of more than one type of CE or CE-like activity.
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Affiliation(s)
- C Chevillard
- I.N.S.E.R.M. U.300, Faculté de Pharmacie, Montpellier, France
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44
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Aussel C, Laliberté F, Masseyeff R. Alpha-fetoprotein favours accumulation of estrone but not arachidonic acid into the fetal and new-born rat brain. Life Sci 1985; 36:479-84. [PMID: 2578598 DOI: 10.1016/0024-3205(85)90261-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Tritriated estrone or arachidonic acid, two high affinity ligands for rat alpha-fetoprotein (AFP), were injected into adult, pregnant or newborn Sprague Dawley rats in order to evaluate their possible transfer into the brain. This study shows that the developing brain accumulates the estrogen but not the fatty acid, suggesting that the uptake of AFP by the developing brain is a mechanism for transporting estrogens, but not fatty acids.
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Abstract
In rodents, maternal immunoglobulins are transported intact by the yolk-sac visceral epithelium from mother to fetus. The main purpose of the present paper is to study the dynamics of the uptake and transport of immunoglobulins by the rat yolk-sac using a new experimental design. The results show the rapid binding of IgG to the cell membrane microvilli since only 30 sec were sufficient for this attachment to occur. The endocytic process also appears to be very fast as localization of IgG in clusters, pits and microvesicles were observed after 5 min of contact between the yolk-sac and the IgG solution. Moreover, the antibodies were detected in the intracellular spaces within 15 min of incubation.
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Abstract
The yolk-sac is known to be a route for the transport of passive immunity from mother to fetus in the rat. The main purpose of the present paper is to describe an experimental system for ultrastructurally studying the kinetics of the uptake and transport of immunoglobulin by rat yolk-sac. This system has the advantage of enabling the membrane to be externalized and then exposed to protein under controlled environmental conditions whilst at the same time maintaining the conceptus in connection with the in situ placenta. Preliminary investigations have utilized homologous anti-horseradish peroxidase (HRP) IgG (detected as antibody by application of HRP) or HRP alone. Comparison has been made with the localization of endogenous IgG transmitted in vivo after immunization of the female rat with HRP. The results show the rapid binding of IgG to membrane since only 30 sec were sufficient for this attachment to occur. Moreover, the endocytic process also appears to be very fast as localization of IgG in clusters or patches, caveolae or pits and even rare microvesicles is observed within 8 min. On the other hand, no binding of HRP to microvilli was observed and, unlike IgG, HRP became located in the apico-tubulocanalicular system.
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47
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Maurice M, Feldmann G, Druet P, Laliberté F, Bouige D. Immunoperoxidase localization of albumin in hepatocytes of nephrotic rats with special reference to changes in the Golgi apparatus. J Transl Med 1979; 40:39-45. [PMID: 368435] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
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48
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Druet P, Bariéty J, Laliberté F, Bellon B, Belair MF, Paing M. Distribution of heterologous antiperoxidase antibodies and their fragments in the superficial renal cortex of normal Wistar-Munich rat: an ultrastructural study. J Transl Med 1978; 39:623-31. [PMID: 368431] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
The distribution of serum proteins in the superficial renal cortex of normal Wistar-Munich rats was studied using a new technique. Heterologous antiperoxidase antibodies (160,000 daltons), their F(ab')2(100,000 daltons), and Fab (50,000 daltons) fragments were injected intravenously and then demonstrated by incubation with free peroxidase after in situ fixation. This technique offered several advantages including easy and uniform detection of the proteins, even in tubular cells, and a high degree of specificity and accuracy. Four findings emerged from this: (1) The glomerular filtration barrier was found to be complete for IgG and incomplete for (ab')2 and Fab fragments. (2) This barrier for IgG was localized in the lamina densa. (3) The filtered proteins were found to be reabsorbed and degraded in the proximal tubule. (4) The three proteins were diffusely detected in the interstitial tissue and in tubular intercellular spaces up to apical tight junctions.
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Bariéty J, Druet P, Laliberté F, Sapin C, Belair MF, Paing M. Ultrastructural evidence, by immunoperoxidase technique, for a tubular reabsoprtion of endogenous albumin in normal rat. J Transl Med 1978; 38:175-80. [PMID: 342822] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
The reabsorption of endogenous albumin in the proximal tubules of the normal Munich-Wistar rat has been studied using immunoperoxidase techniques. The lumina of the superficial proximal tubules were found to remain open after in situ fixation, allowing good penetration of the conjugates. Labeling typical of an endocytotic process was observed only in the proximal tubules. This fact suggests that the glomerular filtration barrier is not an absolute one for denogenous albumin.
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