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Barnard J, Grimaud L, Yafi F. Does Medicaid Cover Penile Prosthesis Surgery? A State-by-State Analysis. J Sex Med 2022. [DOI: 10.1016/j.jsxm.2022.01.034] [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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2
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Park J, Frangieh J, Réthoré L, Roy-Vessieres E, Grimaud L, Henrion D, Legendre C, Legros C. Activation of Nav channels by veratridine in mesenteric arteries: Contractile or relaxation responses? Archives of Cardiovascular Diseases Supplements 2021. [DOI: 10.1016/j.acvdsp.2021.04.100] [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: 12/01/2022]
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3
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Chehaitly A, Guilbaud Guihot A, Grimaud L, Aurriere J, Proux C, Roy-Vessieres E, Henrion D. Role of mitochondrial dynamics in the response of endothelial cells to shear stress during early phase of atherosclerosis. Archives of Cardiovascular Diseases Supplements 2021. [DOI: 10.1016/j.acvdsp.2021.04.088] [Citation(s) in RCA: 1] [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: 10/21/2022]
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4
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Vuillermet C, Rudelle E, Lutz M, Grimaud L, Poggio M, Rogeaux O, Forestier E, Mallaval F. Optimiser la collaboration entre une équipe opérationnelle d’hygiène et un service de maladies infectieuses : un intérêt pour tous ? Med Mal Infect 2020. [DOI: 10.1016/j.medmal.2020.06.456] [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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5
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Rudelle E, Forget V, Gros S, Grimaud L, Covarel S, Trébuchet A, Rogeaux O, Mallaval F, Forestier E. Porter un masque chirurgical (MC) en permanence pour se protéger contre la grippe : est-ce acceptable ? Med Mal Infect 2017. [DOI: 10.1016/j.medmal.2017.03.370] [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: 11/16/2022]
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Favre J, Roy-Vessieres E, Guilbaud Guihot A, Grimaud L, Loufrani L, Lenfant F, Arnal J, Henrion D. Deficiency in Estrogen Receptor alpha membrane signaling is responsible for premature vascular dysfunction in response to flow shear stress in male mice. Archives of Cardiovascular Diseases Supplements 2017. [DOI: 10.1016/s1878-6480(17)30478-0] [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: 10/19/2022]
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7
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Tarhouni K, Guihot A, Vessieres E, Procaccio V, Grimaud L, Abraham P, Lenfant F, Arnal J, Favre J, Loufrani L, Henrion D. Estrogens are needed for the improvement in endothelium-mediated dilation induced by a chronic increase in blood flow in rat mesenteric arteries. Vascul Pharmacol 2016; 80:35-42. [DOI: 10.1016/j.vph.2015.10.004] [Citation(s) in RCA: 6] [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] [Received: 07/06/2015] [Revised: 10/05/2015] [Accepted: 10/09/2015] [Indexed: 01/02/2023]
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Grimaud L, Pétin A, Vaudolon J, Mazouffre S. Perturbations induced by electrostatic probe in the discharge of Hall thrusters. Rev Sci Instrum 2016; 87:043506. [PMID: 27131673 DOI: 10.1063/1.4945563] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Emissive and Langmuir probes are two widely used plasma diagnostic techniques that, when used properly, give access to a wide range of information on the plasma's ions and electrons. We show here that their use in small and medium power Hall thrusters produces large perturbations in the discharge characteristics. Potential measurements performed by both probes and non-invasive Laser Induced Fluorescence (LIF) spectroscopy highlight significant discrepancies in the discharge profile. This phenomenon is observed both in the 200 W and the 1.5 kW-class thrusters. In order to have a better understanding of these perturbations, ion velocity distribution functions are acquired by LIF spectroscopy at different positions in the smaller thruster, with and without the probes. Emissive probes are shown to produce the biggest perturbation, shifting the acceleration region upstream. The probe insertion is also shown to have significant effect on both the average discharge current, increasing it by as much as 30%, and its harmonic content in both amplitude and spectrum. These perturbations appear as the probe tip passes a threshold located between 0 and 5 mm downstream of the thruster exit plane.
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Affiliation(s)
| | - A Pétin
- ICARE, CNRS, Orléans 45100, France
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9
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Tarhouni K, Freidja ML, Guihot AL, Vessieres E, Grimaud L, Toutain B, Lenfant F, Arnal JF, Loufrani L, Henrion D. Role of estrogens and age in flow-mediated outward remodeling of rat mesenteric resistance arteries. Am J Physiol Heart Circ Physiol 2014; 307:H504-14. [DOI: 10.1152/ajpheart.00986.2013] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
In resistance arteries, a chronic increase in blood flow induces hypertrophic outward remodeling. This flow-mediated remodeling (FMR) is absent in male rats aged 10 mo and more. As FMR depends on estrogens in 3-mo-old female rats, we hypothesized that it might be preserved in 12-mo-old female rats. Blood flow was increased in vivo in mesenteric resistance arteries after ligation of the side arteries in 3- and 12-mo-old male and female rats. After 2 wk, high-flow (HF) and normal-flow (NF) arteries were isolated for in vitro analysis. Arterial diameter and cross-sectional area increased in HF arteries compared with NF arteries in 3-mo-old male and female rats. In 12-mo-old rats, diameter increased only in female rats. Endothelial nitric oxide synthase expression and endothelium-mediated relaxation were higher in HF arteries than in NF arteries in all groups. ERK1/2 phosphorylation, NADPH oxidase subunit expression levels, and arterial contractility to KCl and to phenylephrine were greater in HF vessels than in NF vessels in 12-mo-old male rats only. Ovariectomy in 12-mo-old female rats induced a similar pattern with an increased contractility without diameter increase in HF arteries. Treatment of 12-mo-old male rats and ovariectomized female rats with hydralazine, the antioxidant tempol, or the angiotensin II type 1 receptor blocker candesartan restored HF remodeling and normalized arterial contractility in HF vessels. Thus, we found that FMR of resistance arteries remains efficient in 12-mo-old female rats compared with age-matched male rats. A balance between estrogens and vascular contractility might preserve FMR in mature female rats.
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Affiliation(s)
- K. Tarhouni
- L'Université Nantes Angers Le Mans University and University of Angers, Angers, France
| | - M. L. Freidja
- L'Université Nantes Angers Le Mans University and University of Angers, Angers, France
| | - A. L. Guihot
- Unité Mixte de Recherche 6214, Centre National de la Recherche Scientifique, Angers, France
| | | | - L. Grimaud
- L'Université Nantes Angers Le Mans University and University of Angers, Angers, France
- CHU d'Angers, Angers, France; and
| | - B. Toutain
- L'Université Nantes Angers Le Mans University and University of Angers, Angers, France
| | - F. Lenfant
- U858, Institut National de la Santé et de la Recherche Médicale, Université Toulouse III Paul Sabatier, CHU de Toulouse, Toulouse, France
| | - J. F. Arnal
- U858, Institut National de la Santé et de la Recherche Médicale, Université Toulouse III Paul Sabatier, CHU de Toulouse, Toulouse, France
| | - L. Loufrani
- L'Université Nantes Angers Le Mans University and University of Angers, Angers, France
- Unité Mixte de Recherche 6214, Centre National de la Recherche Scientifique, Angers, France
- U1083, Institut National de la Santé et de la Recherche Médicale, Angers, France
- CHU d'Angers, Angers, France; and
| | - D. Henrion
- L'Université Nantes Angers Le Mans University and University of Angers, Angers, France
- Unité Mixte de Recherche 6214, Centre National de la Recherche Scientifique, Angers, France
- U1083, Institut National de la Santé et de la Recherche Médicale, Angers, France
- CHU d'Angers, Angers, France; and
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Kauffenstein G, Pizard A, Le Corre Y, Vessières E, Grimaud L, Toutain B, Labat C, Mauras Y, Gorgels TG, Bergen AA, Le Saux O, Lacolley P, Lefthériotis G, Henrion D, Martin L. Disseminated arterial calcification and enhanced myogenic response are associated with abcc6 deficiency in a mouse model of pseudoxanthoma elasticum. Arterioscler Thromb Vasc Biol 2014; 34:1045-56. [PMID: 24675664 DOI: 10.1161/atvbaha.113.302943] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
OBJECTIVE Pseudoxanthoma elasticum is an inherited metabolic disorder resulting from ABCC6 gene mutations. It is characterized by progressive calcification and fragmentation of elastic fibers in the skin, retina, and the arterial wall. Despite calcium accumulation in the arteries of patients with pseudoxanthoma elasticum, functional consequences remain unknown. In the present study, we investigated arterial structure and function in Abcc6(-/-) mice, a model of the human disease. APPROACH AND RESULTS Arterial calcium accumulation was evaluated using alizarin red stain and atomic absorption spectrometry. Expression of genes involved in osteochondrogenic differentiation was measured by polymerase chain reaction. Elastic arterial properties were evaluated by carotid echotracking. Vascular reactivity was evaluated using wire and pressure myography and remodeling using histomorphometry. Arterial calcium accumulation was 1.5- to 2-fold higher in Abcc6(-/-) than in wild-type mice. Calcium accumulated locally leading to punctuate pattern. Old Abcc6(-/-) arteries expressed markers of both osteogenic (Runx2, osteopontin) and chondrogenic lineage (Sox9, type II collagen). Abcc6(-/-) arteries displayed slight increase in arterial stiffness and vasoconstrictor tone in vitro tended to be higher in response to phenylephrine and thromboxane A2. Pressure-induced (myogenic) tone was significantly higher in Abcc6(-/-) arteries than in wild type. Arterial blood pressure was not significantly changed in Abcc6(-/-), despite higher variability. CONCLUSIONS Scattered arterial calcium depositions are probably a result of osteochondrogenic transdifferentiation of vascular cells. Lower elasticity and increased myogenic tone without major changes in agonist-dependent contraction evidenced in aged Abcc6(-/-) mice suggest a reduced control of local blood flow, which in turn may alter vascular homeostasis in the long term.
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Affiliation(s)
- Gilles Kauffenstein
- From the CNRS UMR 6214, INSERM U1083, l'UNAM (G.K., Y.L.C., E.V., L.G., B.T., G.L., D.H., L.M.) and Laboratoire de Pharmacologie-Toxicologie, l'UNAM, Université d'Angers (Y.M.), University Hospital Angers, Angers, France; INSERM, U1116 (A.P., C.L., P.L.), Université de Lorraine, Vandoeuvre-lès-Nancy, France; Department of Cell and Molecular Biology, John A. Burns School of Medicine, University of Hawaii, Honolulu, HI (O.L.S.); Molecular Ophthalmogenetics, Netherlands Institute for Neuroscience, Amsterdam, The Netherlands (T.G.G., A.A.B.); and Departments of Ophthalmology (A.A.B.) and Clinical Genetics (A.A.B.), Academic Medical Center, Amsterdam, The Netherlands
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11
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Martinand-Lurin E, Dos Santos A, El Kaim L, Grimaud L, Retailleau P. Double Smiles rearrangement of Passerini adducts towards benzoxazinones. Chem Commun (Camb) 2014; 50:2214-7. [DOI: 10.1039/c3cc49022j] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A new straightforward access to benzoxazinones based on a three-component coupling is presented here.
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Affiliation(s)
- E. Martinand-Lurin
- UPMC-ENS-CNRS-UMR 8640
- Ecole Normale Supérieure-Département de chimie
- 75231 Paris cedex 05, France
- UPR 2301 CNRS
- Centre de Recherche de Gif-sur-Yvette
| | - A. Dos Santos
- UMR 7652 (Ecole Polytechnique/ENSTA/CNRS)
- Laboratoire Chimie et Procédés
- ENSTA-ParisTech
- , France
| | - L. El Kaim
- UMR 7652 (Ecole Polytechnique/ENSTA/CNRS)
- Laboratoire Chimie et Procédés
- ENSTA-ParisTech
- , France
| | - L. Grimaud
- UPMC-ENS-CNRS-UMR 8640
- Ecole Normale Supérieure-Département de chimie
- 75231 Paris cedex 05, France
| | - P. Retailleau
- UPR 2301 CNRS
- Centre de Recherche de Gif-sur-Yvette
- Institut de Chimie des Substances Naturelles
- 91198 Gif-sur-Yvette, France
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Tarhouni K, Guihot AL, Freidja ML, Toutain B, Henrion B, Baufreton C, Pinaud F, Procaccio V, Grimaud L, Ayer A, Loufrani L, Lenfant F, Arnal JF, Henrion D. Key role of estrogens and endothelial estrogen receptor α in blood flow-mediated remodeling of resistance arteries. Arterioscler Thromb Vasc Biol 2013; 33:605-11. [PMID: 23288162 DOI: 10.1161/atvbaha.112.300334] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
OBJECTIVE Flow- (shear stress-)mediated outward remodeling of resistance arteries is involved in collateral growth during postischemic revascularization. As this remodeling is especially important during pregnancy, we hypothesized that estrogens may be involved. A surgical model eliciting a local increase in blood flow in 1 mesenteric resistance artery was used in 3-month-old ovariectomized female rats either treated with 17-β-estradiol (E2) or left untreated. METHODS AND RESULTS After 14 days, arterial diameter was greater in high-flow arteries than in normal-flow vessels. An ovariectomy suppressed high-flow remodeling, while E2 restored it. High-flow remodeling was absent in mice lacking the estrogen receptor α but not estrogen receptor β. The kinetics of inflammatory marker expression, macrophage infiltration, oxidative stress, and metaloproteinases expression were not altered by the absence of E2 after 2 and 4 days, that is, during remodeling. Nevertheless, E2 was required for the increase in endothelial nitric oxide synthase expression and activation at day 4 when diameter expansion occurs. Finally, the impact of E2 on the endothelium appeared crucial for high-flow remodeling, as this E2 action was abrogated in mice lacking endothelial NOS, as well as in Tie2-Cre(+) ERα(f/f) mice. CONCLUSIONS We demonstrate the essential role of E2 and endothelial estrogen receptor α in flow-mediated remodeling of resistance arteries in vivo.
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Affiliation(s)
- K Tarhouni
- LUNAM Université and Université d’Angers, Angers, France
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Ancel J, El Kaı̈m L, Gadras A, Grimaud L, Jana N. Studies towards the synthesis of Fipronil® analogues: improved decarboxylation of α-hydrazonoacid derivatives. Tetrahedron Lett 2002. [DOI: 10.1016/s0040-4039(02)01977-9] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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14
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El Kaı̈m L, Grimaud L, Jana N, Tirla C. α-Nitrohydrazones: versatile intermediates for phosphonate derivatives formation from primary nitro compounds. Tetrahedron Lett 2002. [DOI: 10.1016/s0040-4039(02)00208-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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15
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Rapp C, Coutant G, Béchade D, Camparo P, Grimaud L, Baranger B, Desramé J, Helie C, Algayres J. Pseudo-tumeur inflammatoire ganglionnaire abdominale révélée par une fièvre prolongée inexpliquéeet un érythème noueux. Rev Med Interne 2001. [DOI: 10.1016/s0248-8663(01)80186-7] [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: 10/25/2022]
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Viret J, Grimaud L, Jimenez J. Hydrodynamic modelling of stress. Acta Biotheor 2000; 47:173-90. [PMID: 10855265 DOI: 10.1023/a:1002674201334] [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] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
This work is a qualitative study of an organism's physiological adaptative response to stress. The experimental data were selected from a previous study leading to the conclusion that stress may be considered as a topological retraction within a vital space that must be more precisely defined. The experimental methodology uses rat poisoning by neurotoxins. The control parameter is the intensity of the toxic doses. Measured parameters are the animals' survival rate and the kinetics of cerebral acetylcholinesterase activity. The results, when expressed as a function of the inverted doses, show a characteristic evolution. The pattern of the curve closely resembles a vortex profile. This analogy is studied more extensively in both the physical and biological domains. These findings help to clarify the concept of biological stress which presents the same vectorial properties as hydrodynamic vorticity. In particular, the dissipation of stress and the dissipation of vorticity seem to obey the same laws. This observation is valid for both diffusion and convection processes. The decompensation phase of stress could be compared with the instability and turbulence in flows. Our approach in this paper is mainly to establish a general and phenomenological description of the stress response fitting experimental observations.
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Gineyts E, Cloos PA, Borel O, Grimaud L, Delmas PD, Garnero P. Racemization and isomerization of type I collagen C-telopeptides in human bone and soft tissues: assessment of tissue turnover. Biochem J 2000; 345 Pt 3:481-5. [PMID: 10642505 PMCID: PMC1220781] [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: 02/15/2023]
Abstract
Urinary excretion of the type I collagen C-telopeptide (CTx) has been shown to be a sensitive index of the rate of bone resorption. The human type I collagen sequence A(1209)HDGGR(1214) of CTx can undergo racemization of the aspartic acid residue Asp(1211) and isomerization of the bond between this residue and Gly(1212). These spontaneous non-enzymic chemical reactions takes place in vivo in bone, and the degree of racemization and isomerization of CTx molecules may be an index of the biological age and the remodelling of bone. The aim of the present study was to investigate the degree of racemization and isomerization of type I collagen in human connective soft tissues, in order to estimate the rate of collagen turnover in adult tissues and compare it with that of bone. We also performed a systematic evaluation of the pyridinium cross-link content in adult human tissues. Using antibodies raised against the different CTx forms, we found that bone and dermis are the tissues that show most racemization and isomerization. The type I collagen of arteries, lung, intestine, kidney, skeletal muscle and heart shows significantly less racemization and isomerization than that of bone, suggesting that these soft tissues have a faster turnover than bone. We also found that pyridinoline and, to a lesser degree, deoxypyridinoline are distributed throughout the different tissues investigated. Because bone type I collagen is characterized by a high degree of both racemization/isomerization and deoxypyridinoline cross-linking, the concomitant assessment of these two post-translational modifications is likely to result in a highly specific marker of bone resorption.
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Affiliation(s)
- E Gineyts
- INSERM U403, Hôpital E.Herriot, pavillon F, place d'Arsonval, 69437 Lyon cedex 03, France.
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Marot-Leblond A, Grimaud L, Nail S, Bouterige S, Apaire-Marchais V, Sullivan DJ, Robert R. New monoclonal antibody specific for Candida albicans germ tube. J Clin Microbiol 2000; 38:61-7. [PMID: 10618064 PMCID: PMC86019 DOI: 10.1128/jcm.38.1.61-67.2000] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Hydrophobic components of the germ tube of the dimorphic pathogenic fungus Candida albicans were used as immunogens to prepare monoclonal antibodies (MAbs). Among the resulting MAbs, one (MAb 16B1-F10) was shown by indirect immunofluorescence to be specific to the surface of the mycelium phase of the C. albicans and C. stellatoidea species. No labeling of any other genera and Candida species tested was observed, including C. dubliniensis, a newly described species which has many phenotypic similarities to C. albicans. This phase-specific epitope resides on a protein moiety. The molecular mass of the antigen released by Zymolyase digestion was determined by gel filtration and ranges from 25 to 166 kDa. The antigen was also shown to be highly hydrophobic. This anti-C. albicans cell wall surface-specific MAb may be a good candidate for use in tests for the rapid differentiation of the two closely related species C. albicans and C. dubliniensis.
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Affiliation(s)
- A Marot-Leblond
- Groupe d'Etude des Interactions Hôte-Parasite, UFR des Sciences Pharmaceutiques et d'Ingénierie de la Santé, 49100 Angers, France.
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Michel F, Grimaud L, Tuosto L, Acuto O. Fyn and ZAP-70 are required for Vav phosphorylation in T cells stimulated by antigen-presenting cells. J Biol Chem 1998; 273:31932-8. [PMID: 9822663 DOI: 10.1074/jbc.273.48.31932] [Citation(s) in RCA: 83] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
In T cells, triggering of the T cell antigen receptor or of the co-stimulatory receptor CD28 can direct tyrosine phosphorylation of the signaling protein Vav. We investigated the role played by the protein tyrosine kinases Fyn, Lck, and ZAP-70 in these processes in a T cell hybridoma after physiological stimulation of the T cell receptor (TCR) and CD28. A dominant-negative mutant approach based on overexpression of catalytically inactive alleles of these kinases showed that CD28-induced Vav phosphorylation preferentially requires Fyn, whereas ZAP-70 had no role. Consistently, Vav was strongly phosphorylated in Lck-deficient JCAM-1 cells after CD28 ligation. In contrast, ZAP-70 appeared to control TCR-directed Vav phosphorylation. However, overexpression of ZAP-70 carrying a mutated Tyr315, contained within a motif previously suggested to be a Vav Src homology 2 domain binding site, had little or no effect. Immunoprecipitation assays showed that phosphorylated Vav associated with Fyn after CD28 triggering and that this interaction, likely to involve binding of Fyn Src homology 2 domain to Vav, was more strongly detectable after concomitant CD28 and TCR stimulation. These data suggest that Fyn plays a major role in controlling Vav phosphorylation upon T cell activation and that the mechanism implicating ZAP-70 in this process may be more complex than previously anticipated.
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Affiliation(s)
- F Michel
- Molecular Immunology Unit, Department of Immunology, Institut Pasteur, 25 Rue du Docteur Roux, 75724 Paris Cedex 15, France
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