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Diamond-Ouellette G, Telonio A, Karakolis T, Leblond J, Bouyer L, PhD KB. Exploring the change in metabolic cost of walking before and after familiarization with a passive load-bearing exoskeleton: A case series. IISE Trans Occup Ergon Hum Factors 2022; 10:161-172. [DOI: 10.1080/24725838.2022.2124325] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/14/2022]
Affiliation(s)
- G. Diamond-Ouellette
- Centre for Interdisciplinary Research in Rehabilitation and Social Integration (CIRRIS), Centre intégré universitaire de santé et de service sociaux de la Capitale-Nationale, Quebec City, Canada
| | | | - T. Karakolis
- Operational Health and Performance Section, Defence Research and Development Canada, Toronto, Canada
| | - J. Leblond
- Centre for Interdisciplinary Research in Rehabilitation and Social Integration (CIRRIS), Centre intégré universitaire de santé et de service sociaux de la Capitale-Nationale, Quebec City, Canada
| | - L.J. Bouyer
- Centre for Interdisciplinary Research in Rehabilitation and Social Integration (CIRRIS), Centre intégré universitaire de santé et de service sociaux de la Capitale-Nationale, Quebec City, Canada
- Department of Rehabilitation, Université Laval, Quebec City, QC, Canada
| | - K.L. Best PhD
- Centre for Interdisciplinary Research in Rehabilitation and Social Integration (CIRRIS), Centre intégré universitaire de santé et de service sociaux de la Capitale-Nationale, Quebec City, Canada
- Department of Rehabilitation, Université Laval, Quebec City, QC, Canada
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Pérez‐Rosales G, Pichon M, Rouzé H, Villéger S, Torda G, Bongaerts P, Carlot J, Parravicini V, Hédouin L, Bardout G, Fauchet J, Ferucci A, Gazzola F, Lagarrigue G, Leblond J, Marivint E, Mittau A, Mollon N, Paulme N, Périé‐Bardout E, Pete R, Pujolle S, Siu G. Cover Image. DIVERS DISTRIB 2022. [DOI: 10.1111/ddi.13558] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
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Pérez‐Rosales G, Pichon M, Rouzé H, Villeger S, Torda G, Bongaerts P, Carlot J, Parravicini V, Hédouin L, Bardout G, Fauchet J, Ferucci A, Gazzola F, Lagarrigue G, Leblond J, Marivint E, Mittau A, Mollon N, Paulme N, Périé‐Bardout E, Pete R, Pujolle S, Siu G. Mesophotic coral ecosystems of French Polynesia are hotspots of alpha and beta generic diversity for scleractinian assemblages. DIVERS DISTRIB 2022. [DOI: 10.1111/ddi.13549] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Affiliation(s)
- Gonzalo Pérez‐Rosales
- PSL Research University EPHE‐UPVD‐CNRS USR 3278 CRIOBE Moorea French Polynesia
- PSL Université Paris: EPHE‐UPVD‐CNRS USR 3278 CRIOBE Université de Perpignan Perpignan Cedex France
| | - Michel Pichon
- Biodiversity Section Queensland Museum Townsville Queensland Australia
| | - Héloïse Rouzé
- PSL Université Paris: EPHE‐UPVD‐CNRS USR 3278 CRIOBE Université de Perpignan Perpignan Cedex France
- Marine Laboratory University of Guam Mangilao Guam USA
| | | | - Gergely Torda
- ARC Centre of Excellence for Coral Reef Studies James Cook University Townsville Queensland Australia
| | - Pim Bongaerts
- California Academy of Sciences San Francisco California USA
| | - Jeremey Carlot
- PSL Université Paris: EPHE‐UPVD‐CNRS USR 3278 CRIOBE Université de Perpignan Perpignan Cedex France
| | - Valeriano Parravicini
- PSL Université Paris: EPHE‐UPVD‐CNRS USR 3278 CRIOBE Université de Perpignan Perpignan Cedex France
| | - Laetitia Hédouin
- PSL Research University EPHE‐UPVD‐CNRS USR 3278 CRIOBE Moorea French Polynesia
- PSL Université Paris: EPHE‐UPVD‐CNRS USR 3278 CRIOBE Université de Perpignan Perpignan Cedex France
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Cunningham AJ, Robinson M, Banquy X, Leblond J, Zhu XX. Bile Acid-Based Drug Delivery Systems for Enhanced Doxorubicin Encapsulation: Comparing Hydrophobic and Ionic Interactions in Drug Loading and Release. Mol Pharm 2018; 15:1266-1276. [PMID: 29378128 DOI: 10.1021/acs.molpharmaceut.7b01091] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Doxorubicin (Dox) is a drug of choice in the design of drug delivery systems directed toward breast cancers, but is often limited by loading and control over its release from polymer micelles. Bile acid-based block copolymers present certain advantages over traditional polymer-based systems for drug delivery purposes, since they can enable a higher drug loading via the formation of a reservoir through their aggregation process. In this study, hydrophobic and electrostatic interactions are compared for their influence on Dox loading inside cholic acid based block copolymers. Poly(allyl glycidyl ether) (PAGE) and poly(ethylene glycol) (PEG) were grafted from the cholic acid (CA) core yielding a star-shaped block copolymer with 4 arms (CA-(PAGE- b-PEG)4) and then loaded with Dox via a nanoprecipitation technique. A high Dox loading of 14 wt % was achieved via electrostatic as opposed to hydrophobic interactions with or without oleic acid as a cosurfactant. The electrostatic interactions confer a pH responsiveness to the system. 50% of the loaded Dox was released at pH 5 in comparison to 12% at pH 7.4. The nanoparticles with Dox loaded via hydrophobic interactions did not show such a pH responsiveness. The systems with Dox loaded via electrostatic interactions showed the lowest IC50 and highest cellular internalization, indicating the pre-eminence of this interaction in Dox loading. The blank formulations are biocompatible and did not show cytotoxicity up to 0.17 mg/mL. The new functionalized star block copolymers based on cholic acid show great potential as drug delivery carriers.
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Affiliation(s)
- Alexander J Cunningham
- Département de Chimie , Université de Montréal , CP 6128, Succursale Centre-ville, Montréal , Quebec H3C 3J7 , Canada
| | - Mattieu Robinson
- Département de Gérontologie , Université de Sherbrooke , Sherbrooke , Quebec J1H 4C4 , Canada
| | - Xavier Banquy
- Faculté de Pharmacie , Université de Montréal , CP 6128, Succursale Centre-ville, Montréal , Quebec H3C 3J7 , Canada
| | - Jeanne Leblond
- Faculté de Pharmacie , Université de Montréal , CP 6128, Succursale Centre-ville, Montréal , Quebec H3C 3J7 , Canada
| | - X X Zhu
- Département de Chimie , Université de Montréal , CP 6128, Succursale Centre-ville, Montréal , Quebec H3C 3J7 , Canada
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Plourde K, Derbali RM, Desrosiers A, Dubath C, Vallée-Bélisle A, Leblond J. Aptamer-based liposomes improve specific drug loading and release. J Control Release 2017; 251:82-91. [PMID: 28238787 DOI: 10.1016/j.jconrel.2017.02.026] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2016] [Revised: 01/27/2017] [Accepted: 02/07/2017] [Indexed: 01/02/2023]
Abstract
Aptamer technology has shown much promise in cancer therapeutics for its targeting abilities. However, its potential to improve drug loading and release from nanocarriers has not been thoroughly explored. In this study, we employed drug-binding aptamers to actively load drugs into liposomes. We designed a series of DNA aptamer sequences specific to doxorubicin, displaying multiple binding sites and various binding affinities. The binding ability of aptamers was preserved when incorporated into cationic liposomes, binding up to 15equivalents of doxorubicin per aptamer, therefore drawing the drug into liposomes. Optimization of the charge and drug/aptamer ratios resulted in ≥80% encapsulation efficiency of doxorubicin, ten times higher than classical passively-encapsulating liposomal formulations and similar to a pH-gradient active loading strategy. In addition, kinetic release profiles and cytotoxicity assay on HeLa cells demonstrated that the release and therapeutic efficacy of liposomal doxorubicin could be controlled by the aptamer's structure. Our results suggest that the aptamer exhibiting a specific intermediate affinity is the best suited to achieve high drug loading while maintaining efficient drug release and therapeutic activity. This strategy was successfully applied to tobramycin, a hydrophilic drug suffering from low encapsulation into liposomes, where its loading was improved six-fold using aptamers. Overall, we demonstrate that aptamers could act, in addition to their targeting properties, as multifunctional excipients for liposomal formulations.
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Affiliation(s)
- Kevin Plourde
- Faculty of Pharmacy, University of Montreal, QC H3T 1J4, Canada
| | | | | | - Céline Dubath
- Faculty of Pharmacy, University of Montreal, QC H3T 1J4, Canada
| | | | - Jeanne Leblond
- Faculty of Pharmacy, University of Montreal, QC H3T 1J4, Canada.
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Viricel W, Poirier S, Mbarek A, Derbali RM, Mayer G, Leblond J. Cationic switchable lipids: pH-triggered molecular switch for siRNA delivery. Nanoscale 2017; 9:31-36. [PMID: 27906384 DOI: 10.1039/c6nr06701h] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
A pH-sensitive molecular switch able to change its conformation upon protonation at endosomal pH values is embedded into the structure of cationic lipidoid materials, thus conferring endosomal escape properties. Involvement of the conformational switch in the endosomal escape process was confirmed and leading material identified was able to induce efficient gene knockdown both in vitro and in vivo. The lipid nanoparticles reported here are promising for therapeutic applications and this work could serve as a template for future design of stimulus-responsive (ionic, redox, light) molecular switch for drug and gene delivery.
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Affiliation(s)
- W Viricel
- Faculty of Pharmacy, University of Montreal, P.O. Box 6128, Downtown Station, Montreal, QC, Canada.
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Leblond J, Potier J, Menuel S, Bricout H, Machut-Binkowski C, Landy D, Tilloy S, Monflier E, Hapiot F. Water-soluble phosphane-substituted cyclodextrin as an effective bifunctional additive in hydroformylation of higher olefins. Catal Sci Technol 2017. [DOI: 10.1039/c7cy01108c] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Cyclodextrins substituted with a sulfophenyl phosphane show an excellent recognition ability towards higher olefins in aqueous biphasic Rh-catalyzed hydroformylation.
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Affiliation(s)
- J. Leblond
- Univ. Artois
- CNRS
- Centrale Lille
- ENSCL
- Univ. Lille
| | - J. Potier
- Univ. Lille
- CNRS
- INRA
- ENSCL
- UMR 8207 – UMET – Unité Matériaux et Transformations
| | - S. Menuel
- Univ. Artois
- CNRS
- Centrale Lille
- ENSCL
- Univ. Lille
| | - H. Bricout
- Univ. Artois
- CNRS
- Centrale Lille
- ENSCL
- Univ. Lille
| | | | - D. Landy
- Univ. Littoral
- Unité de Chimie Environnementale et Interactions sur le Vivant (UCEIV, EA 4492)
- SFR Condorcet FR CNRS 3417
- ULCO
- F-59140 Dunkerque
| | - S. Tilloy
- Univ. Artois
- CNRS
- Centrale Lille
- ENSCL
- Univ. Lille
| | - E. Monflier
- Univ. Artois
- CNRS
- Centrale Lille
- ENSCL
- Univ. Lille
| | - F. Hapiot
- Univ. Artois
- CNRS
- Centrale Lille
- ENSCL
- Univ. Lille
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Giraud L, Viricel W, Leblond J, Giasson S. Single stranded siRNA complexation through non-electrostatic interactions. Biomaterials 2017; 113:230-242. [DOI: 10.1016/j.biomaterials.2016.10.035] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2016] [Revised: 10/19/2016] [Accepted: 10/23/2016] [Indexed: 11/24/2022]
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Viricel W, Mbarek A, Leblond J. Cover Picture: Switchable Lipids: Conformational Change for Fast pH-Triggered Cytoplasmic Delivery (Angew. Chem. Int. Ed. 43/2015). Angew Chem Int Ed Engl 2015. [DOI: 10.1002/anie.201507428] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Viricel W, Mbarek A, Leblond J. Titelbild: Switchable Lipids: Conformational Change for Fast pH-Triggered Cytoplasmic Delivery (Angew. Chem. 43/2015). Angew Chem Int Ed Engl 2015. [DOI: 10.1002/ange.201507428] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Noreau L, Leblond J, Dumont F. The SCI Community Survey: Highlights related to met or unmet needs for services after return in community living. Ann Phys Rehabil Med 2015. [DOI: 10.1016/j.rehab.2015.07.058] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Viricel W, Mbarek A, Leblond J. Switchable Lipids: Conformational Change for Fast pH-Triggered Cytoplasmic Delivery. Angew Chem Int Ed Engl 2015; 54:12743-7. [PMID: 26189870 DOI: 10.1002/anie.201504661] [Citation(s) in RCA: 59] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2015] [Indexed: 12/31/2022]
Abstract
We report the use of switchable lipids to improve the endosomal escape and cytosolic delivery of cell-impermeable compounds. The system is based on a conformational reorganization of the lipid structure upon acidification, as demonstrated by NMR spectroscopic studies. When incorporated in a liposome formulation, the switchable lipids triggered bilayer destabilization through fusion even in the presence of poly(ethylene glycol). We observed 88 % release of sulforhodamine B in 15 min at pH 5, and the liposome formulations demonstrated high stability at pH 7.4 for several months. By using sulforhodamine B as a model of a highly polar drug, we demonstrated fast cytosolic delivery mediated by endosomal escape in HeLa cells, and no toxicity.
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Affiliation(s)
- Warren Viricel
- Faculty of Pharmacy, University of Montreal, P.O. Box 6128, Downtown Station, Montreal, Quebec (Canada)
| | - Amira Mbarek
- Faculty of Pharmacy, University of Montreal, P.O. Box 6128, Downtown Station, Montreal, Quebec (Canada)
| | - Jeanne Leblond
- Faculty of Pharmacy, University of Montreal, P.O. Box 6128, Downtown Station, Montreal, Quebec (Canada).
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Brodeur MR, Bouvet C, Bouchard S, Moreau S, Leblond J, deBlois D, Moreau P. Reduction of advanced-glycation end products levels and inhibition of RAGE signaling decreases rat vascular calcification induced by diabetes. PLoS One 2014; 9:e85922. [PMID: 24465790 PMCID: PMC3897559 DOI: 10.1371/journal.pone.0085922] [Citation(s) in RCA: 63] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2013] [Accepted: 12/03/2013] [Indexed: 11/18/2022] Open
Abstract
Advanced-glycation end products (AGEs) were recently implicated in vascular calcification, through a process mediated by RAGE (receptor for AGEs). Although a correlation between AGEs levels and vascular calcification was established, there is no evidence that reducing in vivo AGEs deposition or inhibiting AGEs-RAGE signaling pathways can decrease medial calcification. We evaluated the impact of inhibiting AGEs formation by pyridoxamine or elimination of AGEs by alagebrium on diabetic medial calcification. We also evaluated if the inhibition of AGEs-RAGE signaling pathways can prevent calcification. Rats were fed a high fat diet during 2 months before receiving a low dose of streptozotocin. Then, calcification was induced with warfarin. Pyridoxamine was administered at the beginning of warfarin treatment while alagebrium was administered 3 weeks after the beginning of warfarin treatment. Results demonstrate that AGEs inhibitors prevent the time-dependent accumulation of AGEs in femoral arteries of diabetic rats. This effect was accompanied by a reduced diabetes-accelerated calcification. Ex vivo experiments showed that N-methylpyridinium, an agonist of RAGE, induced calcification of diabetic femoral arteries, a process inhibited by antioxidants and different inhibitors of signaling pathways associated to RAGE activation. The physiological importance of oxidative stress was demonstrated by the reduction of femoral artery calcification in diabetic rats treated with apocynin, an inhibitor of reactive oxygen species production. We demonstrated that AGE inhibitors prevent or limit medial calcification. We also showed that diabetes-accelerated calcification is prevented by antioxidants. Thus, inhibiting the association of AGE-RAGE or the downstream signaling reduced medial calcification in diabetes.
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MESH Headings
- Animals
- Antioxidants/pharmacology
- Aorta/metabolism
- Aorta/pathology
- Diabetes Mellitus, Experimental/complications
- Diabetes Mellitus, Experimental/metabolism
- Diabetes Mellitus, Experimental/physiopathology
- Femoral Artery/drug effects
- Femoral Artery/pathology
- Femoral Artery/physiopathology
- Glycation End Products, Advanced/metabolism
- Hemodynamics/drug effects
- Male
- Muscle, Smooth, Vascular/pathology
- Myocytes, Smooth Muscle/drug effects
- Myocytes, Smooth Muscle/metabolism
- Myocytes, Smooth Muscle/pathology
- Oxidation-Reduction/drug effects
- Pyridinium Compounds
- Rats
- Rats, Wistar
- Receptor for Advanced Glycation End Products
- Receptors, Immunologic/metabolism
- Signal Transduction/drug effects
- Vascular Calcification/etiology
- Vascular Calcification/metabolism
- Vascular Calcification/pathology
- Vascular Calcification/physiopathology
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Affiliation(s)
| | - Céline Bouvet
- Faculty of Pharmacy, Université de Montréal, Montréal, Québec, Canada
| | - Sonia Bouchard
- Faculty of Pharmacy, Université de Montréal, Montréal, Québec, Canada
| | - Simon Moreau
- Faculty of Pharmacy, Université de Montréal, Montréal, Québec, Canada
| | - Jeanne Leblond
- Faculty of Pharmacy, Université de Montréal, Montréal, Québec, Canada
| | - Denis deBlois
- Faculty of Pharmacy, Université de Montréal, Montréal, Québec, Canada
| | - Pierre Moreau
- Faculty of Pharmacy, Université de Montréal, Montréal, Québec, Canada
- * E-mail:
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Leblond J, Petitjean A. Inside Cover: Molecular Tweezers: Concepts and Applications (ChemPhysChem 6/2011). Chemphyschem 2011. [DOI: 10.1002/cphc.201190029] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Abstract
Taken to the molecular level, the concept of "tweezers" opens a rich and fascinating field at the convergence of molecular recognition, biomimetic chemistry and nanomachines. Composed of a spacer bridging two interaction sites, the behaviour of molecular tweezers is strongly influenced by the flexibility of their spacer. Operating through an "induced-fit" recognition mechanism, flexible molecular tweezers select the conformation(s) most appropriate for substrate binding. Their adaptability allows them to be used in a variety of binding modes and they have found applications in chirality signalling. Rigid spacers, on the contrary, display a limited number of binding states, which lead to selective and strong substrate binding following a "lock and key" model. Exquisite selectivity may be expressed with substrates as varied as C(60) , nanotubes and natural cofactors, and applications to molecular electronics and enzyme inhibition are emerging. At the crossroad between flexible and rigid spacers, stimulus-responsive molecular tweezers controlled by ionic, redox or light triggers belong to the realm of molecular machines, and, applied to molecular tweezing, open doors to the selective binding, transport and release of their cargo. Applications to controlled drug delivery are already appearing. The past 30 years have seen the birth of molecular tweezers; the next many years to come will surely see them blooming in exciting applications.
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Affiliation(s)
- Jeanne Leblond
- Faculté de Pharmacie, Université de Montréal, Montréal, QC, Canada
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Abstract
Molecular tweezers are dynamic devices that are able to switch from one conformation to another upon stimulation by an external trigger. In this work, we report a new water-soluble macromolecular carrier bearing a pH-responsive molecular tweezer, whose affinity for a substrate depends on the external pH. The conformational change of the switching unit was evidenced by (1)H NMR spectroscopy, and fluorescence studies conducted in aqueous media demonstrated the ability of the carrier to bind to substrates in a pH-dependent fashion.
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Breton M, Leblond J, Seguin J, Midoux P, Scherman D, Herscovici J, Pichon C, Mignet N. Comparative gene transfer between cationic and thiourea lipoplexes. J Gene Med 2010; 12:45-54. [PMID: 19937995 DOI: 10.1002/jgm.1417] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
BACKGROUND We have previously developed lipopolythiourea lipids as neutral DNA condensing agents for systemic gene delivery. Optimization of the lipopolythiourea structure led to efficient transfecting agents. To further evaluate these lipids, we investigated the internalization process of the thiourea lipoplexes and their intracellular mechanism of transfection versus that of cationic lipoplexes. METHODS The MTT test was used for cytotoxicity assessment. Transfection efficiency was determined by luciferase read-out. Permeation to propidium iodide and enhanced green fluorescent protein was evaluated by flow cytometry. Kinetics of internalization and DNA release were monitored by confocal microscopy with labelled DNA. Endocytosis inhibitors were used to study the mechanisms of lipoplex internalization. RESULTS Although thiourea/DNA complexes exhibit an almost similar level of transfection compared to that of cationic complexes, the thiourea lipoplexes were shown to be six-fold less internalized. Complexes were able to permeabilize the cytoplasmic membrane to 30 kDa molecules. Finally, DNA was shown to be released in less than 10 min in the cellular cytoplasm versus 30 min for cationic lipoplexes. CONCLUSIONS Despite a weaker internalization compared to cationic lipids, the thiourea lipoplexes were able to transfect cells at a similar level as a result of its greater ability to destabilize the cytoplasmic membrane and release DNA.
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Affiliation(s)
- Marie Breton
- Inserm, U640, CNRS, UMR8151, Unité de Pharmacologie Chimique et Génétique, Université Paris Descartes, Faculté de Pharmacie, Paris, France
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Leblond J, Mignet N, Largeau C, Seguin J, Scherman D, Herscovici J. Lipopolythiourea Transfecting Agents: Lysine Thiourea Derivatives. Bioconjug Chem 2007; 19:306-14. [DOI: 10.1021/bc7001924] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Jeanne Leblond
- Inserm, U640, Paris F-75006, France, CNRS, UMR8151, Paris F-75006, France, Ecole Nationale Supérieure de Chimie de Paris, Paris F-75005, France, Unité de Pharmacologie Chimique et Génétique, France, Université Paris-Descartes, Faculté de Pharmacie, Paris F-75270, France, and Chimie Moléculaire de Paris Centre, CNRS, FR 2769, Paris F-75005, France
| | - Nathalie Mignet
- Inserm, U640, Paris F-75006, France, CNRS, UMR8151, Paris F-75006, France, Ecole Nationale Supérieure de Chimie de Paris, Paris F-75005, France, Unité de Pharmacologie Chimique et Génétique, France, Université Paris-Descartes, Faculté de Pharmacie, Paris F-75270, France, and Chimie Moléculaire de Paris Centre, CNRS, FR 2769, Paris F-75005, France
| | - Céline Largeau
- Inserm, U640, Paris F-75006, France, CNRS, UMR8151, Paris F-75006, France, Ecole Nationale Supérieure de Chimie de Paris, Paris F-75005, France, Unité de Pharmacologie Chimique et Génétique, France, Université Paris-Descartes, Faculté de Pharmacie, Paris F-75270, France, and Chimie Moléculaire de Paris Centre, CNRS, FR 2769, Paris F-75005, France
| | - Johanne Seguin
- Inserm, U640, Paris F-75006, France, CNRS, UMR8151, Paris F-75006, France, Ecole Nationale Supérieure de Chimie de Paris, Paris F-75005, France, Unité de Pharmacologie Chimique et Génétique, France, Université Paris-Descartes, Faculté de Pharmacie, Paris F-75270, France, and Chimie Moléculaire de Paris Centre, CNRS, FR 2769, Paris F-75005, France
| | - Daniel Scherman
- Inserm, U640, Paris F-75006, France, CNRS, UMR8151, Paris F-75006, France, Ecole Nationale Supérieure de Chimie de Paris, Paris F-75005, France, Unité de Pharmacologie Chimique et Génétique, France, Université Paris-Descartes, Faculté de Pharmacie, Paris F-75270, France, and Chimie Moléculaire de Paris Centre, CNRS, FR 2769, Paris F-75005, France
| | - Jean Herscovici
- Inserm, U640, Paris F-75006, France, CNRS, UMR8151, Paris F-75006, France, Ecole Nationale Supérieure de Chimie de Paris, Paris F-75005, France, Unité de Pharmacologie Chimique et Génétique, France, Université Paris-Descartes, Faculté de Pharmacie, Paris F-75270, France, and Chimie Moléculaire de Paris Centre, CNRS, FR 2769, Paris F-75005, France
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Leblond J, Mignet N, Leseurre L, Largeau C, Bessodes M, Scherman D, Herscovici J. Design, synthesis, and evaluation of enhanced DNA binding new lipopolythioureas. Bioconjug Chem 2007; 17:1200-8. [PMID: 16984129 DOI: 10.1021/bc060110g] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Nonviral gene delivery is limited to a large extent by the cationic nature of most of the chemical vector. We have shown that lipopolythioureas interact with DNA. However, lipopolythioureas were not very efficient at transfecting cells, probably due to reduced interaction between the noncationic synthetic lipid and the cell membrane. Here, we report that liposomes made from a new thiourea lipid, DPPC, and a lipid bearing an RGD ligand allowed very efficient entry of the lipopolythioureas into integrin alpha(v)beta(3) expressing cells. In addition, we show that a stable interaction between DNA and lipopolythiourea could be obtain with two thiourea groups. Moreover, the addition of a hydrophilic terminus improves the formulation of these new DNA binding agents.
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Leblond J, Mignet N, Largeau C, Spanedda MV, Seguin J, Scherman D, Herscovici J. Lipopolythioureas: A New Non-Cationic System for Gene Transfer. Bioconjug Chem 2007; 18:484-93. [PMID: 17373770 DOI: 10.1021/bc060141b] [Citation(s) in RCA: 32] [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: 11/29/2022]
Abstract
A DNA-transfection protocol has been developed that makes use of thiourea non-cationic synthetic lipid, N-[1,3-bis(carbamothioylamino)propan-2-yl]-2-(dialkycarbamoylmethoxy)acetamide. It was found that these new compounds could be formulated without helper lipid and that the N-decanoyl and N-lauryl derivatives transfected B16 cells in the presence of serum with an efficiency at the same level as cationic lipids, under identical conditions. In vivo transfection using intratumoral injection was also investigated. It was found that compounds 18c and 19 showed an efficiency of the same magnitude as naked DNA and cationic lipid.
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Affiliation(s)
- Jeanne Leblond
- Inserm, U640, Paris, F-75006, CNRS, UMR8151, Paris, F-75006, Ecole Nationale Supérieure de Chimie de Paris, Paris, France
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23
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Abstract
We present a neutral lipopolythiourea (DTTU) as a potential DNA-binding agent. Light scattering experiments showed that mixing a lipopolythiourea with dipalmitoylphosphatidylcholine (DPPC/DTTU) led to small particles with sizes ranging from 100 to 150 nm at optimum conditions. Setting a fixed DNA amount, an increasing amount of DTTU/DPPC or DPPC lipids was added. Particle size increased only with DTTU/DPPC, indicating that interaction occurred between the DTTU/DPPC particles and DNA. In the same way, only DTTU/DPPC limited the ethidium bromide accessibility to plasmid DNA. These data suggest that DTTU/DPPC liposomes associate to DNA, which was confirmed by agarose gel experiments. To prove the active part of the DTTU lipid itself in DNA compaction, pegoylated-lipid was used. Cholesterol-PEG(2000) alone was not able to condense DNA. In contrast, DTTU/PEG-cholesterol was able to retain plasmid DNA on an agarose gel. In vivo injection of DTTU/DPPC/complexes was studied. Circulation time increase for noncationic particles as compared to cationic. More obvious was the lack of nonspecific accumulation in the lung, where a gain of 3 to 40 fold was measured.
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Affiliation(s)
- Isabelle Tranchant
- Laboratoire de Pharmacologie Chimique et Génétique CNRS-UMR 8115, INSERM-U640, ENSCP 11 rue Pierre et Marie Curie 75231 Paris Cedex 05, France
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Ladouceur R, Bouchard C, Rhéaume N, Jacques C, Ferland F, Leblond J, Walker M. Is the SOGS an accurate measure of pathological gambling among children, adolescents and adults? J Gambl Stud 2004; 16:1-24. [PMID: 14634319 DOI: 10.1023/a:1009443516329] [Citation(s) in RCA: 157] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
The South Oaks Gambling Screen (SOGS) is widely used to assess the prevalence of pathological gambling. For a variety of reasons, this instrument may not provide an accurate rate of the prevalence of pathological gambling. In this paper, one source of error in data provided by the SOGS is investigated. It is argued that individuals may not fully understand the meaning of some items, and that clarification of the meaning of misunderstood items may in some cases lead to a changed score on the scale. The present study evaluates respondents' understanding of the SOGS items. The results from three studies are reported, each using a different sample: grade school children, adolescents and adults. It was hypothesised that (1) participants would not understand some items of the SOGS, (2) problem gamblers and probable pathological gamblers would be more inclined to interpret items incorrectly than would non-problem gamblers and, (3) consistent with the first two hypotheses, clarification of items would decrease the number of participants identified as problem gamblers or probable pathological gamblers. The data obtained supported hypotheses 1 and 3. Furthermore, hypothesis 2 was supported for grade school children, but not for adolescents or adults. These results are consistent with recent literature on endorsement and acquiescence phenomena, and have implications for prevalence studies of probable pathological gambling.
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Affiliation(s)
- R Ladouceur
- Ecole de Psychologie, Université Laval, Québec, Québec, Canada, G1K 7P4.
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25
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Abstract
As gambling facilities become more available, the number of pathological gamblers increases. Effective therapeutic and preventive interventions should be developed and systematically evaluated. Self-exclusion programs may be a useful means to facilitate self-control among problem gamblers. This paper describes the characteristics of individuals who decided to bar themselves from a Canadian casino. Two hundred twenty individuals participated in the present study and completed a questionnaire including four sections: (1) socio-demographic data, (2) the South Oaks Gambling Screen, (3) gambling habits, and (4) prior experiences with the self-exclusion program. According to the SOGS, 95% of the participants were classified as severe pathological gamblers on the SOGS (Mean score = 9.87). Furthermore, based on self-reported observation, 30% of the participants completely stopped gambling once enrolled in this program. No one scored within the interval of non-problem gamblers. Suggestions to improve self-exclusion programs are discussed.
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Affiliation(s)
- R Ladouceur
- Ecole de Psychologie, Université Laval, Ste-Foy, Quebec, Canada G1K 7P4.
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26
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Abstract
This study evaluated the efficacy of a group cognitive treatment for pathological gambling. Gamblers, meeting DSM-IV criteria for pathological gambling, were randomly assigned to treatment (N=34) or wait-list control (N=24) conditions. Cognitive correction techniques were used first to target gamblers' erroneous perceptions about randomness, and then to address issues of relapse prevention. The dependent measures used were the DSM-IV criteria for pathological gambling, perceived self-efficacy, gamblers' perception of control, desire to gamble, and frequency of gambling. Post-treatment results indicated that 88% of the treated gamblers no longer met the DSM-IV criteria for pathological gambling compared to only 20% in the control group. Similar changes were observed on all outcome measures. Analysis of data from 6-, 12- and 24-month follow-ups revealed maintenance of therapeutic gains. Recommendations for group interventions are discussed, focusing on the cognitive correction of erroneous perceptions toward the notion of randomness.
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Affiliation(s)
- R Ladouceur
- Ecole de Psychologie, Université Laval, Quebec, G1K 7P4, Ste-Foy, Canada.
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Lebon L, Leblond J. PFG NMR measurements of flow through porous media: effects of spatial correlations of the magnetic field and the velocity field. J Magn Reson 2002; 159:13-24. [PMID: 12468299 DOI: 10.1016/s1090-7807(02)00119-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Used for a long time for diffusion studies, PFG NMR techniques are now widely used to study flow through porous media. We discuss here the effects of the magnetic field inhomogeneities and the finite gradient pulse duration in this case. We propose a statistical model based on spatial correlations of the magnetic field and velocity field and as far as we can, we draw practical conclusions on the PFG NMR measurements conditions.
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Affiliation(s)
- L Lebon
- Laboratoire de Physique et Mécanique des Milieux Hétérogènes, UMR 7636 CNRS, ESPCI 10 rue Vauquelin, 75231 05, Paris cedex, France.
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Abstract
This study evaluated the efficacy of a cognitive treatment package for pathological gambling. Sixty-six gamblers, meeting DSM-IV criteria for pathological gambling, were randomly assigned to treatment or wait-list control conditions. Cognitive correction techniques were used first to target gamblers' erroneous perceptions about randomness and then to address issues of relapse prevention. The dependent measures used were the South Oaks Gambling Screen, the number of DSM-IV criteria for pathological gambling met by participants, as well as gamblers' perception of control, frequency of gambling, perceived self-efficacy, and desire to gamble. Posttest results indicated highly significant changes in the treatment group on all outcome measures, and analysis of data from 6- and 12-month follow-ups revealed maintenance of therapeutic gains. Recommendations for clinical interventions are discussed, focusing on the cognitive correction of erroneous perceptions toward the notion of randomness.
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Affiliation(s)
- R Ladouceur
- Department of Psychology, Université Laval, Ste-Foy, Quebec, Canada
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Leblond J, Javelot S, Lebrun D, Lebon L. Two-phase flow characterization by nuclear magnetic resonance. Nuclear Engineering and Design 1998. [DOI: 10.1016/s0029-5493(98)00199-x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Talini L, Leblond J, Feuillebois F. A Pulsed Field Gradient NMR Technique for the Determination of the Structure of Suspensions of Non-Brownian Particles with Application to Packings of Spheres. J Magn Reson 1998; 132:287-297. [PMID: 9632555 DOI: 10.1006/jmre.1998.1389] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
The internal structure of systems of particles in a liquid is studied with a novel NMR technique based on the measurement of the squared modulus of the magnetization in presence of a pulsed field gradient. The formalism is analogous to the one used in classical scattering techniques (light, X-rays, neutrons); it allows similar information to be obtained about the structure (in particular, the structure factor S(q)). The main improvement is that the range of particles sizes is 10 µm to 1 mm, as compared with the range of the scattering techniques (<5 µm). The NMR technique was validated by studying packings of spherical particles of mean diameter 240 µm created by sedimentation. The profile of the experimental squared modulus of the magnetization versus the wave vector provides results for the mean size of particles and the compacity. The main feature is that it depends on the pair distribution function, and the present results are in good agreement with a model based on the Percus-Yevick approximation. This technique is then particularly adapted to systems such as non-Brownian suspensions, fluidized beds, porous media, and sediments. Copyright 1998 Academic Press.
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Affiliation(s)
- L Talini
- ESPCI, URA 857 au CNRS, 10 rue Vauquelin, Paris Cedex 05, 75231, France
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Lebon L, Leblond J, Hulin JP, Martys NS, Schwartz LM. Pulsed field gradient NMR measurements of probability distribution of displacement under flow in sphere packings. Magn Reson Imaging 1996; 14:989-91. [PMID: 8970131 DOI: 10.1016/s0730-725x(96)00203-2] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
In this work we used the PFG NMR displacement technique to investigate the transport of water particles under flow through a model porous media. Using different sizes of sphere for monodisperse glass sphere packings, we measured the probability distribution of displacement for mean displacements ranging from 0.08 to 7.3 times the characteristic length of the porous media. We observed, therefore, the transition between the velocity probability distribution and the Gaussian-shaped distribution of classical dispersion.
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Affiliation(s)
- L Lebon
- Laboratoire PMMH, ESPCI, Paris, France
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Disant F, Leblond J. [Reconstruction of the external ear]. Rev Prat 1992; 42:2069-74. [PMID: 1485115] [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: 12/27/2022]
Abstract
The authors after a short morphological description of the microtia, expose the surgical evolution which had led to the actual auricular reconstruction technique, using a costal cartilage framework. This technique requiring several steps is exposed in the typical case of microtia. It is the preferential method. The difficult reconstructions due to the poor quality of the skin are exposed by degree of complexity: in these cases, tissue expansion, fascia temporalis superficialis can be useful and finally auricular prostheses, attached to bone-integrated implants, can be recommended. The functional surgery of the middle ear is also replaced in the context of the auricular reconstruction which is done around 8 years old.
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Affiliation(s)
- F Disant
- Service d'ORL et de chirurgie cervico-faciale, pavillon U, hôpital Edouard-Herriot, Lyon
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34
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Disant F, Leblond J. [Nasosinusal and pharyngeal infections in children. Etiology, physiopathology, diagnosis, principles of treatment]. Rev Prat 1991; 41:1421-4. [PMID: 2063146] [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] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
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Abstract
1. Extracellular [K] and [Ca] were measured with ion-selective microelectrodes in CA1 pyramidal cell layer of rat hippocampal slices in an interface chamber. 2. Near room temperature (21-22 degrees C), brief periods of anoxia (3- to 4-min substitution of 95% N2-5% CO2 for 95% O2-5% CO2) produced very small changes in [K]o [-0.022 +/- 0.10 (SE) mM] or [Ca]o (-0.030 +/- 0.0029 mM) and were associated with only minor depression of population spikes (-22.5 +/- 11%). 3. Stratum radiatum (SR) stimulation (0.2-5 Hz) could evoke substantial increases in [K]o (by 0.2-2 mM); although variable, they were consistent in any one slice. The same stimulation regularly caused only small depressions of [Ca]o (by less than 0.1 mM, typically). 4. Also at 21-22 degrees neither stimulation nor anoxia generated more than minimal reductions in extracellular space [by 2.3 +/- 0.94%, as measured by the tetramethylammonium (TMA) method], and spreading depression (SD) occurred in only 1 out of 20 slices. 5. At 33-34 degrees C, anoxia (also for 3-4 min) consistently produced more substantial increases in [K]o (0.83 +/- 0.18 mM); but the apparent changes in [Ca]o at 33 degrees C (0.058 +/- 0.12 mM) could not with certainty be distinguished from thermoelectric artifacts. There was a severe depression of population spikes (-76 +/- 10%). 6. Although electrical stimulation evoked greater reductions in [Ca]o, increases in [K]o were 50% smaller. 7. During anoxia at 33-34 degrees C, the extracellular space was significantly reduced, by 6.1 +/- 0.9%. Moreover, in 37% of the slices, either stimulation or anoxia triggered massive increases in [K]o (greater than 10 mM) and large reductions in [Ca]o (less than 1 mM), associated with SD-like swings in focal potential. 8. It is concluded that the extracellular ionic changes evoked by brief anoxia do not contribute in a major way to the depression of synaptic transmission.
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Affiliation(s)
- M E Morris
- Anaesthesia Research Department, McGill University, Montreal, Quebec, Canada
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Herning T, Djabourov M, Leblond J, Takerkart G. Conformation of gelatin chains in aqueous solutions: 2. A quasi-elastic light scattering study. POLYMER 1991. [DOI: 10.1016/0032-3861(91)90144-8] [Citation(s) in RCA: 57] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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Abstract
1. Reversible effects of brief periods of anoxia (replacing 95% O2-5% CO2 with 95% N2-5% CO2 for 2-4 min) were studied in CA1 neurons in hippocampal slices (from Sprague-Dawley rats), kept in an interface-type chamber at 33.5 degree. 2. The predominant voltage change during anoxia (N2) was a hyperpolarization, accompanied by a marked fall in resistance and excitability; synaptic potentials were also depressed, especially inhibitory postsynaptic potentials (IPSPs). 3. In voltage-current (V-I) plots, the N2-evoked hypolarization had a reversal potential below -90mV, even when recording with 2 M KCl electrodes and after substituting 90% of medium Cl- with isethionate. The accompanying fall in input resistance (RN) is therefore probably caused by an increase in K conductance (in agreement with previous reports). There was evidence that anomalous rectification enhances the fall in RN but limits the hyperpolarization. 4. These effects of anoxia were not fully blocked by any of the K-channel antagonists tested, including Cs, TEA, 4-AP, quinine and apamin. 5. Intracellular injections of Ca chelators caused a variable depression of N2-evoked reductions in RN. 6. It is unlikely that N2 activates ATP-sensitive K channels as tolbutamide enhanced rather than depressed the hyperpolarization and fall in RN. 7. When early depletion of cellular ATP was prevented by incubation in creatine (25 mM for greater than 1 h), even longer anoxic periods produced only minor changes in potential, RN, and synaptic transmission. 8. It was concluded that activation of K conductance by a rise in cytosolic-free Ca2+ is the most plausible of several possible underlying mechanisms.
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Affiliation(s)
- J Leblond
- Anaesthesia Research, Department McGill University, Montréal, Québec, Canada
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Abstract
1. Effects of anoxia (2-4 min of 95% N2-5% CO2) on membrane currents of CA1 neurons were studied by single-electrode voltage clamp in hippocampal slices (from Sprague-Dawley rats) kept in an interface-type chamber at 33.5 degree. 2. When recording with KCl electrodes at a holding potential (VH) near-70 mV, anoxia evoked a slow outward current [0.18 +/- 0.06 (SE) nA], accompanied by a conductance increase ( + 46 +/- 20%, mean +/- SE). The difference current evoked by N2 had a reversal potential near-100 mV. It was much smaller in presence of 2-4 mM extracellular Cs, and any remaining outward current was abolished by 10 mM tetraethylammonium (TEA). Only inward currents were observed when recording with CsCl electrodes. 3. Inward relaxations evoked by large hyperpolarizing pulses from VH less than or equal to - 70 mV (Q-type) were not significantly depressed by anoxia (-1.5 +/- 6.0%). 4. Some voltage-dependent outward currents (evoked by 200-ms depolarizing pulses) were depressed during anoxia: 1) a fast-inactivating (A-like) current, obtained at VH less than or equal to -70 mV and suppressed by 200 microM 4-AP, was reduced by 25.6 +/- 7.3% (n = 5); 2) a slower, noninactivating (C-like) current, suppressed by TEA, was reduced by 52 +/- 7.2% (n = 16). Neither of these currents (1 or 2) was observed when recording with 2- to 3-M CsCl electrodes; and 3) small (M-like) inward relaxations, observed at VH approximately -40 mV 5. Net inward currents could be evoked after blockage of GK with 10 mM TEA when recording with KCl electrodes or by recording with CsCl electrodes. At VH less than or equal to -70 mV, large, transient, and incompletely controlled currents were evoked by depolarizing pulses; at VH less than or equal to -50 mV, smaller and more persistent currents were evoked by depolarizing pulses (L-like), and transient currents (T-like?) were seen immediately after hyperpolarizing pulses. 6.L-type currents (at VH less than or equal to -50 mV) were nearly abolished after 1-2 min anoxia (by approximately 90%). This was equally true of the currents evoked by constant pulses or peak currents in I-V plots. After reoxygenation, recovery was biphasic, with a quick early phase (to 50-80% in 2 min) and then a much slower one (to 60-90% by 10-15 min).(ABSTRACT TRUNCATED AT 400 WORDS)
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Affiliation(s)
- K Krnjević
- Anaethesia Research Department, McGill University, Montréal, Québec Canada
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41
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Abstract
In experiments on the hippocampus in situ (in rats under urethane), neither cyclic GMP nor H-8 (an antagonist of cyclic nucleotide-dependent kinases) had much effect on CA1/CA3 population spikes or on the excitatory action of ACh. This is further evidence against the idea that cyclic nucleotides play a major role as cholinergic second messengers. On the other hand, the results of tests with a PKC antagonist sphinganine are in keeping with some involvement of PKC in cholinergic actions. (Another PKC antagonist, H-7, proved to be a very powerful excitant, probably via disinhibition). Preliminary experiments on CA1 neurons in hippocampal slices (by single electrode voltage clamp), confirmed previous reports that carbachol depresses A- and C-type K currents, as well as inward Ca2+ currents; though the latter effect was sometimes mainly due to frequency-dependent inactivation of Ca currents. It is suggested that a single, primary muscarinic action, the acceleration of phosphinositide turnover, may account for a variety of secondary effects: on the one hand, via activation of PKC, a number of possible PKC-mediated actions, such as block of the slow AHP; on the other, via IP3 formation, a block of IM and a rise in cycloplasmic free Ca2+ that may cause inactivation of both Ca2(+)-inward currents, and Ca2(+)-dependent GKs.
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Affiliation(s)
- N Agopyan
- Anaesthesia Research Department, McGill University, Montréal, Québec, Canada
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42
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Abstract
Intracellular recording from CA1 neurons confirmed that short periods of anoxia (95% N2 + 5% CO2 for 2-4 min) have a hyperpolarizing action, caused by a rise in K conductance. After blockage of K channels with extracellular Cs+ and tetraethylammonium (or intracellular Cs+), large inward currents of Ca were evoked by depolarizing pulses: transient currents at a holding potential near -70 mV, and more sustained ones near -50 mV. Both types of Ca current were much reduced or fully suppressed after 1-3 min of anoxia, but they largely (or fully) recovered within 1-10 min of starting reoxygenation.
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Affiliation(s)
- K Krnjević
- Anaesthesia Research Department, McGill University, Montréal, Qué., Canada
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Leblond J, Hareng M. Physical properties of superheated water at one bar : a base to define the « normal » components of expansivity and compressibility of stable water. ACTA ACUST UNITED AC 1984. [DOI: 10.1051/jphys:01984004502037300] [Citation(s) in RCA: 10] [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: 11/15/2022]
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Cedard L, Bedin M, Leblond J, Tanguy G, Kaminski M. Maternal plasma total oestriol and dehydroepiandrosterone sulfate loading test as indicators of feto-placental function or placental sulfatase deficiency. J Steroid Biochem 1979; 11:501-7. [PMID: 158678 DOI: 10.1016/0022-4731(79)90074-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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50
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