36 results on '"F. Chiron"'
Search Results
2. Caractéristiques de l’activité thanatologique de deux instituts médico-légaux français durant le confinement de 2020
- Author
-
L. Krebs-Drouot, V. Scolan, F. Savall, F. Paysant, N. Telmon, E. Revel, and F. Chiron
- Subjects
Pathology and Forensic Medicine - Published
- 2022
- Full Text
- View/download PDF
3. [Implementation of a territorial hospital pharmacy (PUI) ensuring a robotized nominative dispensation of treatments for two external sites: A dependent old people's home (EHPAD) and a follow-up care institution (SSR)]
- Author
-
M, Moine, J, Jerome, E, Camps, F, Chiron, E, Brivoal, O, Shaddoud, P, Jack, and B, Bonan
- Subjects
Narcotics ,Automation ,Humans ,Aftercare ,Medication Errors ,Pharmacy Service, Hospital - Abstract
The territorial hospital pharmacy (PUI) of the West of Paris, dispenses treatments for a follow-up care instituion (SSR) and a dependent old people's home (EHPAD) via a hospital pharmacy equipped with an automatic machine producing dry oral forms packaged in labeled pillboxes. This project was completed with the support of the Regional Health Agency (ARS) and aims to secure the medication circuit. The methodology for qualifying the computer system and production, the implementation of the medication circuit and the inter-site logistical organization are presented. The prescription software was interfaced with the management software, which is itself interfaced with the robot's, and with the automatic machine's software. Tests and developments allowed to convert dispensing units into prescription units over a period of time. Also, the drugs consumed by these two institutions allowed to establish the therapeutic booklet and drug provision as well as anticipating the automaton filling. Medical devices, solutions and narcotics are exclusively managed as supplies with a specific circuit. Treatments are dispensed weekly (pillboxes and off-robot). For the SSR, an additional daily production concerns the entries of new patients and the modifications of treatment. Automation saves time and security, but human intervention is involved on a daily basis. The institutions have adopted the new organization over about 6 months and the production activity is now smoothed out. In the next few weeks, two other EHPADs with 100 patients will be integrated into the PUI territorial. One of the main challenges is to integrate them into our pre-existing organization, while maintaining their habits.
- Published
- 2021
4. Evaluation of Preclinical Activity of Isatuximab in Patients with Acute Lymphoblastic Leukemia
- Author
-
Gang Zheng, Marielle F. Chiron Blondel, Anlai Wang, Xueyan Chen, Srimathi Srinivasan, Elvis Shehu, Zhili Song, Chen Zhu, Céline Nicolazzi, Francisco Adrian, and Jonathan R. Fromm
- Subjects
Cancer Research ,Cell ,Apoptosis ,Mice, SCID ,CD38 ,Antibodies, Monoclonal, Humanized ,Mice ,In vivo ,hemic and lymphatic diseases ,Tumor Cells, Cultured ,Medicine ,Animals ,Humans ,Receptor ,Cell Proliferation ,Antibody-dependent cell-mediated cytotoxicity ,Severe combined immunodeficiency ,business.industry ,Lymphoblast ,Antibody-Dependent Cell Cytotoxicity ,hemic and immune systems ,Precursor Cell Lymphoblastic Leukemia-Lymphoma ,medicine.disease ,Prognosis ,Xenograft Model Antitumor Assays ,Survival Rate ,medicine.anatomical_structure ,Oncology ,Cell culture ,Cancer research ,Female ,business - Abstract
This study reports the pharmacologic effects of isatuximab, a CD38 mAb, on T- and B-cell acute lymphoblastic leukemia (ALL). We analyzed CD38 expression in 50-T-ALL and 50 B-ALL clinical samples, and 16 T-ALL and 11 B-ALL cell lines. We primarily focused on in vitro assessments of isatuximab-mediated antibody-dependent cellular cytotoxicity (ADCC) and antibody-dependent cellular phagocytosis (ADCP). In vivo assessment of isatuximab activity was performed in several ALL xenograft models, including disseminated and subcutaneous tumor models in female C.B-17 severe combined immunodeficiency mice. Our study reveals that most patients (90%–100%) carried CD38+ blasts independent of disease burden. The median CD38 receptor density on abnormal lymphoblasts is 41,026 copies/cell on T-ALL and 28,137 copies/cell on B-ALL, respectively. In patients with T-ALL, there is a significant increase of CD38 expression in abnormal blasts compared with normal T cells. High-level CD38 receptor density (RD) is critical to trigger effective isatuximab-mediated ADCC against target ALL cells. In addition, a correlation between CD38 RD and isatuximab-mediated ADCP is demonstrated. In the disseminated CD38+, T-ALL, and B-ALL xenograft models, isatuximab is able to induce robust antitumor activity, even at low doses. This study shows that isatuximab has significant in vitro and in vivo activity against ALL cells with robust ADCC and ADCP effects that are associated with CD38 expression levels in both T-ALL and B-ALL.
- Published
- 2021
5. Fatal road crash under the influence of 4-fluoroamphétamine (4-FA) and cannabis : Who is guilty?
- Author
-
Nathalie Allibe, H. Eysseric, V. Scolan, Françoise Stanke-Labesque, C. Scherpereel, Théo Willeman, and F. Chiron
- Subjects
4-Fluoroamphetamine ,medicine.medical_specialty ,Road crash ,biology ,business.industry ,Health, Toxicology and Mutagenesis ,Medicine ,Cannabis ,Toxicology ,business ,Psychiatry ,biology.organism_classification ,medicine.drug - Published
- 2021
- Full Text
- View/download PDF
6. L’éloignement influence-t-il les demandes d’autopsies ? L’activité thanatologique dans 3 instituts médico-légaux en 2012 : analyse descriptive des conclusions d’autopsie
- Author
-
F. Paysant, A. Giordano, F. Savall, V. Scolan, F. Grenier, L. Martrille, F. Chiron, and M. Vergnault
- Subjects
03 medical and health sciences ,0302 clinical medicine ,Philosophy ,010401 analytical chemistry ,030216 legal & forensic medicine ,01 natural sciences ,Humanities ,0104 chemical sciences ,Pathology and Forensic Medicine - Abstract
Resume Introduction En France, la decision de pratiquer une autopsie, lorsqu’un obstacle medico-legal est etabli, incombe au magistrat enqueteur. Il est demontre que la realisation de l’autopsie reduit le risque d’erreur dans la determination du mode et de la cause du deces. Malgre la suppression, en 2011 de la tarification a l’acte des autopsies, des considerations budgetaires peuvent entrer en jeu, notamment en fonction de la distance entre le lieu du deces et le lieu de la realisation de l’autopsie. L’objectif de cette etude etait de comparer les circonstances de deces selon leur survenue dans des zones eloignees ou des zones proches du lieu d’autopsies. Methodes L’ensemble des rapports d’autopsie des instituts medico-legaux de Grenoble, Nancy et Toulouse pour l’annee 2012 ont ete recueillis et anonymises. Le tribunal demandeur, le mode de deces, l’âge et le sexe du defunt et la cause pathologique de la mort ont ete renseignes. Les codes de la classification internationale des maladies ont ete utilises pour les causes de deces. L’hypothese principale etait que la repartition entre modes de deces violents et non violents etaient differentes entre les tribunaux proches des instituts medico-legaux et les tribunaux eloignes. Les comparaisons entre les donnees observees et les donnees attendues ont ete effectuees a l’aide du test du Chi 2 . Resultats Sept cent quarante-quatre rapports d’autopsie rediges en 2012 ont pu etre analyses. Il n’a pas ete observe de difference significative permettant de valider l’hypothese principale : les autopsies pour morts violentes demandees par les tribunaux proches representaient 278 autopsies contre 243 en peripherie, et les circonstances non violentes respectivement 134 et 84 autopsies ( p [Chi 2 ] = 0,09). Seuls les resultats en sous-groupes de la region grenobloise etaient significatifs. Il a ete mis en evidence que, rapportees au nombre de deces, davantage d’autopsies etaient realisees pour les tribunaux proches du lieu d’autopsie, soit 16,2 autopsies pour 1000 deces, contre 8,3 pour les autopsies realisees pour les tribunaux eloignes. Le materiel etudie, en termes de sex-ratio et d’âge moyen, etait conforme aux autres travaux realises dans ce domaine. Conclusion Cette etude n’a pas permis de montrer une difference significative entre les zones eloignees et proches des instituts medico-legaux quant aux circonstances de deces, cependant le volume d’autopsies rapporte au nombre de deces est plus important pour les zones ou se trouvent le lieu d’autopsie.
- Published
- 2017
- Full Text
- View/download PDF
7. Abstract 2966: Isatuximab-induced multiple myeloma cell killing through effector functions is dependent on CD38 expression and complement inhibitors
- Author
-
Song, Zhili, primary, Yang, Guang, additional, Wang, Anlai, additional, Greco, Rita, additional, Theilhaber, Joachim, additional, Shehu, Elvis, additional, Ajona, Daniel, additional, Paiva, Bruno, additional, Zhu, Chen, additional, Wiederschain, Dmitri, additional, Blondel, Marielle F. Chiron, additional, and Adrian, Francisco, additional
- Published
- 2019
- Full Text
- View/download PDF
8. Décès et dispositifs transdermiques au fentanyl : 9 cas et revue de la littérature
- Author
-
C. Deguette, Renaud Bouvet, G. Lorin de la Grandmaison, J.-M. Gaulier, J.S. Raul, I. Sec, Antoine Tracqui, F. Chiron, and Bertrand Ludes
- Subjects
Gynecology ,medicine.medical_specialty ,business.industry ,Medicine ,business ,Pathology and Forensic Medicine - Abstract
Resume Une serie de 9 deces intervenus dans un contexte d’usage ou de mesusage de dispositifs transdermiques (TD) a base de fentanyl (Durogesic ® ou generiques) est rapportee. Les observations concernent 5 hommes et 4 femmes âges de 26 a 73 ans, avec un nombre de patches impliques compris entre 1 et 16 (doses de 48 a 1500 μg/h). Huit cas correspondaient a des applications multiples de patches au niveau cutane (avec dans un cas une possible injection intraveineuse associee du fentanyl recueilli par deconditionnement d’un ou plusieurs patches), et un cas a l’ingestion d’un patch. Les concentrations sanguines en fentanyl variaient de 2,2 a 234 ng/mL. Au vu des donnees de la litterature, les auteurs insistent sur les difficultes d’interpretation posees par ces situations medico-legales, s’agissant notamment d’apprecier la responsabilite du ou des dispositif(s) TD dans la survenue du deces ; plusieurs facteurs (proximite voire recouvrement entre taux sanguins therapeutiques et toxiques, frequence des polyintoxications, redistribution post-mortem) rendent compte de ces interpretations delicates, et imposent de considerer chaque situation au cas par cas, non seulement au vu des taux sanguins mais aussi de l’ensemble des donnees disponibles (anamnese, autopsie, histologie).
- Published
- 2015
- Full Text
- View/download PDF
9. Comment harmoniser les statistiques en thanatologie ? Un tour d’horizon des instituts médicolégaux français
- Author
-
F. Chiron, V. Scolan, F. Grenier, F. Paysant, and A. Giordano
- Subjects
Pathology and Forensic Medicine - Abstract
Resume Introduction La reforme francaise de 2011 a cree l’observatoire national de la medecine legale. En thanatologie, les donnees recueillies sont succinctes, notamment par rapport aux donnees du bureau du coroner au Quebec. L’objectif de ce travail etait de recenser les methodes statistiques employees dans les instituts medicolegaux francais. Methodes Un entretien telephonique a ete realise aupres des instituts medicolegaux francais. Les questions portaient sur le type de donnees recueillies, le personnel responsable du recueil, le logiciel informatique utilise et le moyen utilise pour le codage des resultats d’autopsie. Resultats Vingt-neuf des 31 instituts medicolegaux ont ete contactes entre mars et mai 2014. Dix-neuf centres (66 %) codaient les resultats d’autopsie a l’aide d’une liste courte de termes, six centres (20 %) utilisaient la classification internationale des maladies, et quatre centres (14 %) ne codifiaient pas leurs resultats d’autopsie. Il n’y avait pas de travail statistique joint entre plusieurs instituts medicolegaux. Conclusion L’utilisation de la classification internationale des maladies pour coder les resultats d’autopsie est effective dans plusieurs instituts medicolegaux francais ; elle peut servir de base methodologique a un travail commun des donnees thanatologiques.
- Published
- 2015
- Full Text
- View/download PDF
10. Abstract 2966: Isatuximab-induced multiple myeloma cell killing through effector functions is dependent on CD38 expression and complement inhibitors
- Author
-
Zhili Song, Rita Greco, Francisco Adrian, Chen Zhu, Dmitri Wiederschain, Anlai Wang, Guang Yang, Daniel Ajona, Bruno Paiva, Joachim Theilhaber, Marielle F. Chiron Blondel, and Elvis Shehu
- Subjects
0301 basic medicine ,Antibody-dependent cell-mediated cytotoxicity ,Cancer Research ,biology ,Chemistry ,Cell ,CD38 ,Molecular biology ,03 medical and health sciences ,030104 developmental biology ,0302 clinical medicine ,medicine.anatomical_structure ,Cell killing ,Oncology ,Cell culture ,030220 oncology & carcinogenesis ,medicine ,biology.protein ,Cytotoxic T cell ,Antibody ,Cytotoxicity - Abstract
Isatuximab (Isa) is an IgG1 monoclonal antibody (Ab) that specifically recognizes human CD38. Once Isa engages multiple myeloma (MM) cells expressing a high level of CD38, it can induce tumor cell killing via Fc-dependent mechanisms including Ab-dependent cell-mediated cytotoxicity (ADCC), Ab-dependent cellular phagocytosis (ADCP), and complement-dependent cytotoxicity (CDC). To better understand the mechanism of Isa-mediated cytotoxicity, we studied CD38 levels in 16 established MM lines and measured Isa-mediated ADCC, ADCP, and CDC in tumor cell killing. The cytotoxic functions of Isa were dependent on CD38 receptor density (RD) in most cell lines. Isa-mediated ADCC was observed in a subset (7/16) of MM cell lines that displayed CD38 RD >100,000 molecules/cell. Similarly, the same subset of MM cells, with 1 exception, were sensitive to Isa-mediated ADCP, indicating a similar CD38 RD is also required for this killing effect. A much higher CD38 RD (>250,000 molecules/cell) alone was insufficient for Isa-mediated CDC. Cell lines MOLP-8 and MOLP-2 have CD38 RD >250,000 molecules/cell, but are resistant to Isa-mediated CDC. Overexpression of CD38 in cell lines with low endogenous CD38 expression did not always sensitize the cells to Isa-mediated CDC. These results suggest that additional mechanisms are involved in the regulation of such cytotoxic effects. We further investigated the expression of complement-cascade inhibitors CD46, CD55, and CD59. High-level expression of at least one of these molecules was associated with resistance to Isa-mediated CDC, even when cells were CD38 high (hi). By comparing 4 selected MM cell lines, we found that a minimal RD level of 50,000 molecules/cell for CD46, CD55 or CD59 appears to be an important threshold to suppress Isa-mediated CDC. When CD59 function was neutralized by an anti-CD59 antibody, we were able to re-sensitize the cells to Isa-mediated CDC in CD38hi MOLP-8 cells. Neutralizing CD59 function alone did not rescue Isa-mediated CDC in CD38-low expressing NCI-H929 cells. However, overexpressing CD38 and inhibiting CD59 rendered NCI-H929 cells sensitive to CDC. Taken together, the high-level of CD38 expression and low-level of CD59 (and perhaps other inhibitors) expression are important for Isa-mediated CDC in killing of target tumor cells. In conclusion, the main immune effector mechanisms involved in Isa-mediated killing of MM cells include ADCC and ADCP. These effects are dependent on high levels of CD38 RD in MM cell lines in vitro. Further confirmation is under way using samples from MM patients. Citation Format: Zhili Song, Guang Yang, Anlai Wang, Rita Greco, Joachim Theilhaber, Elvis Shehu, Daniel Ajona, Bruno Paiva, Chen Zhu, Dmitri Wiederschain, Marielle F. Chiron Blondel, Francisco Adrian. Isatuximab-induced multiple myeloma cell killing through effector functions is dependent on CD38 expression and complement inhibitors [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 2966.
- Published
- 2019
- Full Text
- View/download PDF
11. Ocfentanil, un nouveau produit de synthèse mortel découvert grâce à l’analyse d’une poudre
- Author
-
Françoise Stanke-Labesque, F. Chiron, F. Paysant, V. Scolan, Anne Barret, H. Eysseric, Michel Mallaret, Nathalie Fouilhé Sam-Laï, and Nathalie Allibe
- Subjects
03 medical and health sciences ,0302 clinical medicine ,Health, Toxicology and Mutagenesis ,010401 analytical chemistry ,Toxicology ,030226 pharmacology & pharmacy ,01 natural sciences ,0104 chemical sciences - Abstract
Objectif Presenter le premier cas francais de deces imputable a un NPS analogue du fentanyl [1,2] . Description Une femme de 30 ans est decouverte decedee a son domicile avec a proximite un garrot, des seringues et un sachet de poudre de couleur rose. L’autopsie revele de nombreux points d’injection au niveau du pied gauche et du pli du coude droit et conclut a un deces par syndrome asphyxique avec congestion generalisee des visceres. Methodes Nous disposons de prelevements de sang cardiaque et peripherique, d’humeur vitree, de bile, de contenu gastrique, de cheveux et d’ecouvillons nasaux. Une expertise toxicologique de reference est realisee. La poudre est analysee par GC-MS. Des dosages de confirmation de l’ocfentanil sont realises par LC-MS/MS. Au total, 200 μL d’echantillon sont traites avec 200 μL de reactif de precipitation (acide sulfosalicylique, 500 mg/mL) contenant le standard interne deutere (fentanyl-d5). Apres centrifugation, le surnageant est injecte pour subir une premiere phase d’extraction suivie d’une separation en ligne sur colonne Oasis HLB ® (Waters) puis une separation chromatographique sur colonne XSelect ® (Waters). La quantification est realisee en mode d’ionisation positif sur un API4000 Sciex ® . Deux transitions sont enregistrees pour l’ocfentanil ( m/z : 371,3/105,1 et 371,3/188,2) et 1 transition pour le fentanyl-d5 ( m/z : 342,3/188,2). Resultats Les analyses toxicologiques revelent une alcoolemie a 0,20 g/L, des concentrations sanguines de paracetamol a 3 mg/L, de cafeine a 0,7 mg/L et des traces non quantifiables de morphine libre ( Conclusion Les resultats sont en faveur d’une injection de la poudre ayant entraine un deces imputable a l’ocfentanil, opioide de synthese 3 fois plus puissant que le fentanyl [3] . Les screenings toxicologiques realises en GC-MS, y compris dans la bile, n’ont pas permis de reveler l’ocfentanil a cause de tres faibles concentrations. L’interet majeur pour le diagnostic toxicologique de disposer des produits retrouves pres du corps ou dans l’entourage d’un patient hospitalise, est a rappeler aux enqueteurs, aux cliniciens et aux magistrats.
- Published
- 2017
- Full Text
- View/download PDF
12. Photochemical Hydroperoxidation of Terpenes. Antimicrobial Activity of α-Pinene, β-Pinene and Limonene Hydroperoxides
- Author
-
Jacques Lacoste, V. Sautou, Jean-Claude Chalchat, R. Ph. Garry, and F. Chiron
- Subjects
Terpene ,Limonene ,chemistry.chemical_compound ,Minimum inhibitory concentration ,Pinene ,Chemistry ,Mic values ,Rose bengal ,Organic chemistry ,General Chemistry ,Hydrogen peroxide ,Antimicrobial - Abstract
The rose Bengal photosensitized oxidation of the (+) and (−) stereoisomers of α-pinene, β-pinene and limonene has been optimized to produce sufficient quantities of hydroperoxides for antimicrobial screening. Experimental conditions allowed the production of highly concentrated solutions of hydroperoxides (approximately 2 M, approximately 30 w%). The antimicrobial activity of each hydroperoxide solution was evaluated by measuring their minimum inhibitory concentration (MIC) (1,2). All the hydroperoxides behave as powerful antimicrobial agents (similar to hydrogen peroxide). The MIC values were almost independent of the nature of the parent terpene but depended of the nature of the bacterial colony (five conventional families, met in human pathologies, were tested).
- Published
- 2000
- Full Text
- View/download PDF
13. Photochemical hydroperoxidation of terpenes I. Synthesis and characterization of α-pinene, β-pinene and limonene hydroperoxides
- Author
-
J.C. Chalchat, R.P. Garry, F. Chiron, Jean-François Pilichowski, and Jacques Lacoste
- Subjects
chemistry.chemical_classification ,Limonene ,Anthracene ,Pinene ,General Chemical Engineering ,General Physics and Astronomy ,chemistry.chemical_element ,General Chemistry ,Zinc ,Photochemistry ,Terpene ,chemistry.chemical_compound ,Hydrocarbon ,chemistry ,Rose bengal ,Organic chemistry ,Gas chromatography - Abstract
The photohydroperoxidation of the stereoisomers of three terpenes ((+) and (−) α-pinene, (+) and (−) β-pinene and (+) and (−) limonene) has been performed by using photocatalysts, such as zinc oxide, or sensitizers, such as anthracene or rose Bengal, supported on cross-linked polystyrene. Hydroperoxides accumulated alone in the first stages of sensitized oxidation but were always associated with alcoholic and carbonyl products in the case of ZnO. Secondary products obtained for longer exposure times in sensitized oxidations were identified by gas chromatography/mass spectrometry and mechanisms for their formation, deriving from the photolysis of parent hydroperoxides, were suggested.
- Published
- 1997
- Full Text
- View/download PDF
14. Cleavage of pseudomonas exotoxin and diphtheria toxin by a furin-like enzyme prepared from beef liver
- Author
-
Desmond J. Fitzgerald, Marielle F. Chiron, and Charlotte M. Fryling
- Subjects
Diphtheria toxin ,Proteases ,Protease ,medicine.medical_treatment ,Cell Biology ,Biology ,Cleavage (embryo) ,Biochemistry ,Molecular biology ,Elongation factor ,chemistry.chemical_compound ,chemistry ,biology.protein ,medicine ,Pseudomonas exotoxin ,PMSF ,Molecular Biology ,Furin - Abstract
Pseudomonas exotoxin (PE) is cleaved within mammalian cells between Arg279 and Gly280 to generate an enzymatically active COOH-terminal fragment of 37 kDa which translocates to the cytosol and ADP-ribosylates elongation factor 2. A protease, with toxin cleaving activity, was prepared from beef liver and subsequently characterized. After achieving a 500-fold enrichment in several chromatographic steps, a soluble form of this protease was identified as a furin-like enzyme. It cleaved PE on the COOH-terminal side of the sequence of RQPR (amino acids 276-279) producing the same fragments as those generated within cells. Cleavage had a pH optimum of 5.0-5.5, was inhibited by EDTA or p-hydroxymercuribenzoate but not by O-phenanthroline,N-ethylmaleimide, trans-epoxysuccinyl-L-leukcylamido-(4-guanidino)-butane, or PMSF (or other well known inhibitors of serine proteases). The beef protease cleaved PE with an apparent Km of 7 microM. A mutant form of PE, PEala281, was cleaved at the same site, with the same pH optimum, a similar Km (9 microM) but with a Vmax 150 times faster than was seen with the native toxin. Mutational analysis of the amino acids located just before the site of cleavage, confirmed the importance of arginines at P-1 and P-4. It was also noted that the introduction of a dibasic pair at 278-279 did not increase toxicity or appreciably improve the rate of cleavage. Unnicked diphtheria toxin (DT) was also cleaved by the beef protease; cleavage was on the COOH-terminal side of the sequence RVRR (amino acids 190-193), was seen at pH values ranging from 5.5 to 8.5 and had an optimum at pH 8.0. Recombinant furin cleaved PE, PEala281, and DT with the same characteristics as the beef protease. In addition, Western blot analysis revealed that anti-furin antibodies reacted specifically with components in the beef protease preparation. Immunodepletion experiments showed that all toxin-cleavage activity could be removed from the beef protease using anti-furin antibodies. The relevance of furin-mediated cleavage was further assessed by adding nicked toxins to intact cells. Nicked PE and DT both killed cells at a faster rate than their unnicked counterparts.
- Published
- 1994
- Full Text
- View/download PDF
15. Mechanism of action of Pseudomonas exotoxin. Identification of a rate-limiting step
- Author
-
Ira Pastan, Alexey Zdanovsky, Desmond J. Fitzgerald, and Marielle F. Chiron
- Subjects
chemistry.chemical_classification ,medicine.diagnostic_test ,Endoplasmic reticulum ,Proteolysis ,Cell Biology ,Biology ,medicine.disease_cause ,Biochemistry ,Amino acid ,Elongation factor ,chemistry ,medicine ,Protein biosynthesis ,Pseudomonas exotoxin ,Molecular Biology ,Exotoxin ,Binding domain - Abstract
Pseudomonas exotoxin (PE) enters cells by receptor-mediated endocytosis and is cleaved by a cellular protease between Arg279 and Gly280 to produce an NH2-terminal fragment of 28 kDa which contains the toxin's binding domain and a COOH-terminal fragment of 37 kDa which has translocating and ADP-ribosylating activity. After proteolysis, the COOH-terminal fragment reaches the endoplasmic reticulum by retrograde transport where it translocates to the cytosol and inhibits protein synthesis by ADP-ribosylating elongation factor 2. To understand how the 37-kDa fragment functions, we focused on the role of specific amino acids located near its NH2 terminus. We found that there was a 4-250-fold loss in toxic activity when tryptophan 281, leucine 284, or tyrosine 289 were changed to other residues. Mutations at these three positions did not interfere with the receptor binding, cell-mediated proteolytic cleavage, or ADP-ribosylating activity. To determine the role of these amino acids, a competition assay was devised in which the addition of excess PE delta 553, a mutant form of PE that lacks ADP-ribosylation activity, competed efficiently for the toxicity of PE. Excess PE with mutations near the NH2 terminus of the 37-kDa fragment competed poorly. This competition occurred after proteolysis since PEGly276, a mutant form of PE that is not cleaved, did not complete. We conclude that specific amino acids at the NH2 terminus of the 37-kDa fragment interact in a saturable manner with an unknown intracellular component.
- Published
- 1993
- Full Text
- View/download PDF
16. Design of IEC 61131-3 function blocks using SysML
- Author
-
Khalid Kouiss and F. Chiron
- Subjects
Object-oriented programming ,business.industry ,Computer science ,Programming language ,IEC 61131-3 ,Programmable logic controller ,Applications of UML ,computer.software_genre ,Automation ,Unified Modeling Language ,Systems Modeling Language ,IEC 61131 ,business ,computer ,computer.programming_language - Abstract
UML is almost inevitable when dealing with software designing and intends to be extended to cover many different disciplines. At the same time, control and automation designers integrate further object oriented concepts in their traditional programming behaviors in particular with function blocks. Whereas UML was not adapted to model these IEC 61131 compliant items, an important extension called SysML has been proposed. This paper deals with evaluating the new modeling abilities of this language according to programmable logical controllers specific programming rules.
- Published
- 2007
- Full Text
- View/download PDF
17. [Recombinant immunotoxins and chimeric toxins for targeted therapy in oncology]
- Author
-
M F, Chiron
- Subjects
Cytotoxicity, Immunologic ,Mice ,Immunotoxins ,Recombinant Fusion Proteins ,Bacterial Toxins ,Animals ,Antibodies, Monoclonal ,Antigen-Presenting Cells ,Exotoxins ,Humans ,Immunotherapy ,Neoplasms, Experimental - Abstract
Immunotoxins and chimeric toxins are hybrid molecules constituted of antibodies, growth factor or cytokines coupled to peptide toxins. They are designed to selectively eliminate tumor cells. Some of these chimera have been shown to induce complete tumor regressions of human tumor xenografts in immunodeficient mice. In clinical trials, higher anti tumor response were observed in lymphoma, brain tumor, breast and colon cancers. Problems arose with normal tissue toxicity and the production of neutralising antibodies. Should the latest recombinant toxins conceived by rationale designed, solved these problems, chimeric toxins would be an alternative approach to target tumor cells and vascular endothelial cells in solid tumors.
- Published
- 1998
18. Furin-mediated cleavage of Pseudomonas exotoxin-derived chimeric toxins
- Author
-
David J. FitzGerald, Marielle F. Chiron, and Charlotte M. Fryling
- Subjects
animal structures ,Arginine ,Cell Survival ,viruses ,Recombinant Fusion Proteins ,Exotoxins ,CHO Cells ,Biology ,Cleavage (embryo) ,Biochemistry ,Mice ,Epidermal growth factor ,Immunotoxin ,Cricetinae ,Tumor Cells, Cultured ,Pseudomonas exotoxin ,Animals ,Humans ,Subtilisins ,Molecular Biology ,Furin ,Cell Biology ,Hydrogen-Ion Concentration ,Transforming Growth Factor alpha ,Molecular biology ,Elongation factor ,Kinetics ,Cell culture ,embryonic structures ,biology.protein - Abstract
Pseudomonas exotoxin (PE) requires proteolytic cleavage to generate a 37-kDa C-terminal fragment that translocates to the cytosol and ADP-ribosylates elongation factor 2. Cleavage within cells is mediated by furin, occurs between arginine 279 and glycine 280, and requires an arginine at both P1 and P4 residues. To study the proteolytic processing of PE-derived chimeric toxins, TGFalpha-PE38 (transforming growth factor fused to the domains II and III of PE) and a mutant form, TGFalpha-PE38gly279, were each produced in Escherichia coli. When assessed on various epidermal growth factor (EGF) receptor-positive cell lines, TGFalpha-PE38 was 100-500-fold more toxic than TGFalpha-PE38gly279. In contrast to PE, where cleavage by furin is only evident at pH 5.5, furin cleaved TGFalpha-PE38 over a broad pH range, while TGFalpha-PE38gly279 was resistant to cleavage. TGFalpha-PE38 was poorly toxic for furin-deficient LoVo cells, unless it was first pretreated in vitro with furin. Furin treatment produced a nicked protein that was 30-fold more toxic than its unnicked counterpart. Using the single chain immunotoxin HB21scFv-PE40 as a substrate, furin-mediated processing of an antibody-based immunotoxin was also evaluated. HB21scFv-PE40, which targets cells expressing the transferrin receptor, was cleaved in a similar fashion to that of TGFalpha-PE38 and nicked HB21scFv-PE40 exhibited increased toxicity for LoVo cells. In short-term experiments, the rate of reduction in protein synthesis by furin-nicked immunotoxins was increased compared with unnicked protein, indicating that cleavage by furin can be a rate-limiting step. We conclude that furin-mediated cleavage of PE-derived immunotoxins is important for their cytotoxic activity.
- Published
- 1998
19. Recombinant RFB4 single-chain immunotoxin that is cytotoxic towards CD22-positive cells
- Author
-
Ira Pastan, Desmond J. Fitzgerald, Marielle F. Chiron, Elizabeth Mansfield, and P. Amlot
- Subjects
Leukemia, T-Cell ,Cell Survival ,Virulence Factors ,Recombinant Fusion Proteins ,Sialic Acid Binding Ig-like Lectin 2 ,Bacterial Toxins ,Exotoxins ,Single chain ,Biology ,Biochemistry ,Polymerase Chain Reaction ,law.invention ,Cell Line ,Immunotoxin ,law ,Antigens, CD ,Lectins ,medicine ,Tumor Cells, Cultured ,Cytotoxic T cell ,Humans ,Cloning, Molecular ,DNA Primers ,ADP Ribose Transferases ,Immunotoxins ,CD22 ,Cancer ,Antibodies, Monoclonal ,medicine.disease ,Burkitt Lymphoma ,Antigens, Differentiation, B-Lymphocyte ,Immunoglobulin G ,Cancer research ,Recombinant DNA ,Mutagenesis, Site-Directed ,Immunoglobulin Light Chains ,Immunoglobulin Heavy Chains ,Cell Adhesion Molecules - Abstract
Recombinant RFB4 single-chain immunotoxin that is cytotoxic towards CD22-positive cells E. Mansfield*, M. F. Chiron*, P. Arnlott, I. Pastan* and D. J. FitzGeraldV *Laboratory of Molecular Biology, DBS, National Cancer Institute, National Institutes of Health, 37/4E I 6, 37 Convent Drive MSC 4255, Bethesda, MS 20892, U.S.A., and tDepartment of Immunology, Royal Free Hospital, Rowland Hill Street, London NW3 2PF, U.K.
- Published
- 1997
20. Pseudomonas exotoxin exhibits increased sensitivity to furin when sequences at the cleavage site are mutated to resemble the arginine-rich loop of diphtheria toxin
- Author
-
M Ogata, Marielle F. Chiron, and David J. FitzGerald
- Subjects
medicine.medical_treatment ,Recombinant Fusion Proteins ,Bacterial Toxins ,Exotoxins ,Biology ,Cleavage (embryo) ,Arginine ,Microbiology ,Cell Line ,Mice ,medicine ,Tumor Cells, Cultured ,Pseudomonas exotoxin ,Animals ,Humans ,Diphtheria Toxin ,Trypsin ,Subtilisins ,Molecular Biology ,Furin ,Diphtheria toxin ,chemistry.chemical_classification ,Cleavage stimulation factor ,Protease ,Binding Sites ,Cytotoxins ,Molecular biology ,Amino acid ,Kinetics ,chemistry ,Biochemistry ,Mutagenesis ,Pseudomonas aeruginosa ,biology.protein ,Protein Processing, Post-Translational ,medicine.drug - Abstract
To be toxic for mammalian cells, Pseudomonas exotoxin (PE) requires proteolytic cleavage between Arg-279 and Gly-280. Cleavage, which is mediated by the cellular protease furin, generates an active C-terminal fragment which translocates to the cytosol and inhibits protein synthesis. In vitro, furin-mediated cleavage is optimal at pH 5.5 with a relatively slow turnover rate. Within cells, only 5-10% of cell-associated PE is cleaved. To investigate the reasons for this inefficient cleavage, the amino acid composition near the cleavage site was altered to resemble more closely the arginine-rich sequence from the functionally similar region of diphtheria toxin (DT). Four PE-DT mutants were generated, whereby 1, 5, 6 or 8 amino acids at the PE-cleavage site were changed to amino acids found at the DT-cleavage site. Mutant proteins were expressed in Escherichia coli, purified and then analysed for their susceptibility to cleavage by furin and trypsin, susceptibility to cell-mediated cleavage, and cytotoxic activity relative to wild-type PE. At pH 5.5, the rate of both furin-mediated cleavage and trypsin-mediated cleavage increased dramatically when amino acids in PE were altered to resemble the DT sequence. This increase did not alter the pH optimum for furin-mediated cleavage of PE toxins, which remained at pH 5.0-5.5. When radioactive versions of selected PE-DT proteins were added to intact cells, an increase in the percentage of molecules that were cleaved relative to wild-type PE was also seen. However, changes that favoured increased proteolysis apparently interfered with other important toxin functions because none of the PE-DT proteins exhibited enhanced toxicity for cells when compared with the activity of wild-type PE.
- Published
- 1996
21. Cleavage of pseudomonas exotoxin and diphtheria toxin by a furin-like enzyme prepared from beef liver
- Author
-
M F, Chiron, C M, Fryling, and D J, FitzGerald
- Subjects
ADP Ribose Transferases ,Furin ,Virulence Factors ,Bacterial Toxins ,Exotoxins ,Hydrogen-Ion Concentration ,Cell Line ,Kinetics ,Mice ,Liver ,Mutation ,Animals ,Cattle ,Diphtheria Toxin ,Subtilisins - Abstract
Pseudomonas exotoxin (PE) is cleaved within mammalian cells between Arg279 and Gly280 to generate an enzymatically active COOH-terminal fragment of 37 kDa which translocates to the cytosol and ADP-ribosylates elongation factor 2. A protease, with toxin cleaving activity, was prepared from beef liver and subsequently characterized. After achieving a 500-fold enrichment in several chromatographic steps, a soluble form of this protease was identified as a furin-like enzyme. It cleaved PE on the COOH-terminal side of the sequence of RQPR (amino acids 276-279) producing the same fragments as those generated within cells. Cleavage had a pH optimum of 5.0-5.5, was inhibited by EDTA or p-hydroxymercuribenzoate but not by O-phenanthroline,N-ethylmaleimide, trans-epoxysuccinyl-L-leukcylamido-(4-guanidino)-butane, or PMSF (or other well known inhibitors of serine proteases). The beef protease cleaved PE with an apparent Km of 7 microM. A mutant form of PE, PEala281, was cleaved at the same site, with the same pH optimum, a similar Km (9 microM) but with a Vmax 150 times faster than was seen with the native toxin. Mutational analysis of the amino acids located just before the site of cleavage, confirmed the importance of arginines at P-1 and P-4. It was also noted that the introduction of a dibasic pair at 278-279 did not increase toxicity or appreciably improve the rate of cleavage. Unnicked diphtheria toxin (DT) was also cleaved by the beef protease; cleavage was on the COOH-terminal side of the sequence RVRR (amino acids 190-193), was seen at pH values ranging from 5.5 to 8.5 and had an optimum at pH 8.0. Recombinant furin cleaved PE, PEala281, and DT with the same characteristics as the beef protease. In addition, Western blot analysis revealed that anti-furin antibodies reacted specifically with components in the beef protease preparation. Immunodepletion experiments showed that all toxin-cleavage activity could be removed from the beef protease using anti-furin antibodies. The relevance of furin-mediated cleavage was further assessed by adding nicked toxins to intact cells. Nicked PE and DT both killed cells at a faster rate than their unnicked counterparts.
- Published
- 1994
22. Exploring the Influence of Acid-Base Status on Athletic Performance during Simulated Three-Day 400 m Race.
- Author
-
Chiron F, Erblang M, Gulören B, Bredariol F, Hamri I, Leger D, Hanon C, Tiollier E, and Thomas C
- Subjects
- Humans, Male, Adult, Athletes, Young Adult, Hydrogen-Ion Concentration, Diet methods, Lactic Acid blood, Female, Muscle Fatigue physiology, Running physiology, Physical Endurance physiology, Biomarkers blood, Biomarkers urine, Athletic Performance physiology, Acid-Base Equilibrium, Bicarbonates blood
- Abstract
This study aimed to investigate the ability of highly trained athletes to consistently perform at their highest level during a simulated three-day 400 m race and to examine the impact of an alkaline diet associated with chronic consumption of bicarbonate-rich water or placebo on their blood metabolic responses before and after the three races. Twenty-two highly trained athletes, divided into two groups-one with an alkalizing diet and placebo water (PLA) and the other with an alkalizing diet and bicarbonate-rich water (BIC)-performed a 400 m race for three consecutive days. Performance metrics, urine and blood samples assessing acid-base balance, and indirect markers of neuro-muscular fatigue were measured before and after each 400 m race. The evolution of the Potential Renal Acid Load (PRAL) index and urinary pH highlights the combination of an alkalizing diet and bicarbonate-rich hydration, modifying the acid-base state ( p < 0.05). Athletes in the PLA group replicated the same level of performance during three consecutive daily races without an increase in fatigue-associated markers. Athletes experienced similar levels of metabolic perturbations during the three 400 m races, with improved lactate clearance 20 min after the third race compared to the first two ( p < 0.05). This optimization of the buffering capacity through ecological alkaline nutrition and hydration allowed athletes in the BIC group to improve their performance during the third 400 m race ( p < 0.01). This study highlights athletes' ability to replicate high-level performances over three consecutive days with the same extreme level of metabolic disturbances, and an alkaline diet combined with bicarbonate-rich water consumption appears to enhance performance in a 400 m race.
- Published
- 2024
- Full Text
- View/download PDF
23. Influence of Ingestion of Bicarbonate-Rich Water Combined with an Alkalizing or Acidizing Diet on Acid-Base Balance and Anaerobic Performance.
- Author
-
Chiron F, Thomas C, Bardin J, Mullie F, Bennett S, Chéradame J, Caliz L, Hanon C, and Tiollier E
- Abstract
During high-intensity (HI) exercise, metabolic acidosis significantly impairs exercise performance. Increasing the body's buffering capacity through training and exogenous intake of alkalizing supplements may improve high-intensity performance. Manipulating water and diet intake may influence the acid-base balance. The aim of this study was to determine the effects of mineral water rich in bicarbonate ions (STY) or placebo water (PLA) on circulating biomarkers and anaerobic performance and to verify whether alkalizing (ALK) or acidizing (ACI) diet would modulate these effects. Twenty-four athletes, assigned either to ALK (n = 12) or ACI (n = 12) diet for four weeks, completed a 1-min rowing Wingate Test in a double-blind and randomized trial after one week of daily hydration (1.5 to 2L/d) with either STY or PLA. Blood samples were taken before and after each test, and urine samples were collected each week. Chronic consumption of bicarbonate-rich water significantly impacted resting urinary pH irrespective of alkalizing or acidizing dietary intake. STY induced a significant increase in blood pH, lactate, and HCO
3 - ion concentration post-exercise compared to PLA. Similar changes were observed when STY was associated with the ALK diet. In contrast, STY combined with the ACI diet only significantly affected urine pH and peak blood lactate compared to PLA (p < 0.05). No effect of bicarbonate-rich water was reported on anaerobic performance (p > 0.05). Our results suggest that consumption of bicarbonate-rich water alters acid-base balance during a warm-up and after HI exercise, could potentiate beneficial effects of an alkalizing diet on the acid-base balance after HI exercise, and reduces the acid load induced by an acidifying diet., Competing Interests: The authors declare no conflicts of interest, financial or otherwise. The results are presented honestly without fabrications, falsifications, or inappropriate data manipulation., (Copyright: © Academy of Physical Education in Katowice.)- Published
- 2024
- Full Text
- View/download PDF
24. [Prescription of split doses in a nursing home: Contribution of an automated dose-dispensing machine].
- Author
-
Sauleau L, Moine M, Chiron F, Bonan B, and Jérome J
- Subjects
- Humans, Pharmaceutical Preparations, Drug Prescriptions, Nursing Homes, Medication Errors prevention & control, Pharmacy Service, Hospital
- Abstract
Objectives: The territorial pharmacy of the West of Paris carries out an automated dose dispensing for a nursing home. The machine overpacks dry oral forms in unit doses and dispenses them in named pillboxes. Tablets prescribed in fractions are currently dispensed in whole unit doses, fractioned in advance by a nurse, then administered by a caregiver. These operations present a number of risks, including a break in dose identification right through to administration. The objective was therefore to extend the automated dose dispensing to split tablets by repackaging., Methods: The development of this new process, its software qualification and its evaluation after six months of routine use are described., Results: This process is composed of three steps, secured by pharmaceutical controls: manual production of fractions in the preparatory area, automated repackaging using a barrel and automated dispensing in pillboxes. In total, 2000 fractions were produced in six months with a non-compliance rate lower than 5% and a negligible financial loss. Following the assumption of this activity by the pharmacy, the care team declares themselves satisfied by the gain in time and safety., Conclusions: Automated dispensing of unit doses in fractions ensures identification of the dose from prescription to administration, thus limiting administration errors., (Copyright © 2023 Académie Nationale de Pharmacie. Published by Elsevier Masson SAS. All rights reserved.)
- Published
- 2024
- Full Text
- View/download PDF
25. The magnetic signal from trunk bark of urban trees catches the variation in particulate matter exposure within and across six European cities.
- Author
-
Van Mensel A, Wuyts K, Pinho P, Muyshondt B, Aleixo C, Orti MA, Casanelles-Abella J, Chiron F, Hallikma T, Laanisto L, Moretti M, Niinemets Ü, Tryjanowski P, and Samson R
- Subjects
- Cities, Environmental Monitoring, Magnetic Phenomena, Plant Bark chemistry, Plant Leaves chemistry, Trees, Europe, Air Pollutants analysis, Particulate Matter analysis
- Abstract
Biomagnetic monitoring increasingly is applied to assess particulate matter (PM) concentrations, mainly using plant leaves sampled in small geographical area and from a limited number of species. Here, the potential of magnetic analysis of urban tree trunk bark to discriminate between PM exposure levels was evaluated and bark magnetic variation was investigated at different spatial scales. Trunk bark was sampled from 684 urban trees of 39 genera in 173 urban green areas across six European cities. Samples were analysed magnetically for the Saturation isothermal remanent magnetisation (SIRM). The bark SIRM reflected well the PM exposure level at city and local scale, as the bark SIRM (i) differed between the cities in accordance with the mean atmospheric PM concentrations and (ii) increased with the cover of roads and industrial area around the trees. Furthermore, with increasing tree circumferences, the SIRM values increased, as a reflection of a tree age effect related to PM accumulation over time. Moreover, bark SIRM was higher at the side of the trunk facing the prevailing wind direction. Significant relationships between SIRM of different genera validate the possibility to combine bark SIRM from different genera to improve sampling resolution and coverage in biomagnetic studies. Thus, the SIRM signal of trunk bark from urban trees is a reliable proxy for atmospheric coarse to fine PM exposure in areas dominated by one PM source, as long as variation caused by genus, circumference and trunk side is taken into account., (© 2023. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)
- Published
- 2023
- Full Text
- View/download PDF
26. Phyllosphere bacterial communities in urban green areas throughout Europe relate to urban intensity.
- Author
-
Muyshondt B, Wuyts K, Van Mensel A, Smets W, Lebeer S, Aleixo C, Alós Ortí M, Casanelles-Abella J, Chiron F, Giacomo P, Laanisto L, Moretti M, Niinemets Ü, Pinho P, Tryjanowski P, Woszczyło P, and Samson R
- Subjects
- Bacteria genetics, Humans, Plant Leaves microbiology, Trees microbiology, Biodiversity, Ecosystem
- Abstract
The phyllosphere harbours a diverse and specific bacterial community, which influences plant health and ecosystem functioning. In this study, we investigated the impact of urban green areas connectivity and size on the composition and diversity of phyllosphere bacterial communities. Hereto, we evaluated the diversity and composition of phyllosphere bacterial communities of 233 Platanus x acerifolia and Acer pseudoplatanus trees in 77 urban green areas throughout 6 European cities. The community composition and diversity significantly differed between cities but only to a limited extent between tree species. We could show that urban intensity correlated significantly with the community composition of phyllosphere bacteria. In particular, a significant correlation was found between the relative abundances for 29 out of the 50 most abundant families and the urban intensity: the abundances of classic phyllosphere families, such as Acetobacteraceae, Planctomycetes, and Beijerinkiaceae, decreased with urban intensity (i.e. more abundant in areas with more green, lower air pollution, and lower temperature), while those related to human activities, such as Enterobacteriaceae and Bacillaceae, increased with urban intensity. The results of this study suggest that phyllosphere bacterial communities in European cities are associated with urban intensity and that effect is mediated by several combined stress factors., (© The Author(s) 2022. Published by Oxford University Press on behalf of FEMS.)
- Published
- 2022
- Full Text
- View/download PDF
27. Wild bee larval food composition in five European cities.
- Author
-
Casanelles-Abella J, Keller A, Müller S, Aleixo C, Alós-Orti M, Chiron F, Laanisto L, Myczko Ł, Pinho P, Samson R, Tryjanowski P, Van Mensel A, Villarroya-Villalba L, Pellissier L, and Moretti M
- Subjects
- Animals, Bees, Biodiversity, Cities, Humans, Larva, Ecosystem, Urbanization
- Abstract
Urbanization poses threats and opportunities for the biodiversity of wild bees. At the same time, cities can harbor diverse wild bee assemblages, partly due to the unique plant assemblages that provide resources. While bee dietary preferences have been investigated in various studies, bee dietary studies have been conducted mostly in nonurban ecosystems and data based on plant visitation observations or palynological techniques. This data set describes the larval food preferences of four wild bee species (i.e., Chelostoma florisomne, Hylaeus communis, Osmia bicornis, and O. cornuta) common in urban areas in five different European cities (i.e., Antwerp, Belgium; Paris, France; Poznan, Poland; Tartu, Estonia; and Zurich, Switzerland). In addition, the data set describes the larval food preferences of individuals from three wild bee genera (i.e., Chelostoma sp., Hylaeus sp., and Osmia sp.) that could not be identified to the species level. These data were obtained from a Europe-level study aimed at understanding the effects of urbanization on biodiversity across different cities and cityscapes and a Swiss project aimed at understanding the effects of urban ecosystems in wild bee feeding behavior. Wild bees were sampled using standardized trap nests at 80 sites (32 in Zurich and 12 in each of the remaining cities), selected following a double gradient of available habitat at local and landscape scales. Larval pollen was obtained from the bee nests and identified using DNA metabarcoding. The data provide the plant composition at the species or genus level preferred by each bee. These unique data can be used for a wide array of research questions, including urban ecology (e.g., diversity of food sources along urban gradients), bee ecology (characterization of bee feeding preferences), or comparative studies on the urban evolution of behavioral traits between urban and nonurban sites. In addition, the data can be used to inform urban planning and conservation strategies, particularly concerning flower resources (e.g., importance of exotic species and, thus, management activities). This data set can be freely used for noncommercial purposes, and this data paper should be cited if the data is used; we request that collaboration with the data set contact person to be considered if this data set represents an important part of the data analyzed in a study., (© 2022 The Authors. Ecology published by Wiley Periodicals LLC on behalf of The Ecological Society of America.)
- Published
- 2022
- Full Text
- View/download PDF
28. Exploring multitrophic interactions in oilseed rape fields reveals the prevailing role of Carabidae.
- Author
-
Serée L, Gardarin A, Crouzet O, Barbottin A, Valantin-Morison M, and Chiron F
- Abstract
In cropped fields, birds are often at the highest position in the food chain, feeding on pest arthropods and their intermediate predators in a process known as intraguild predation. The net effects of bird predation on phytophagous insect populations (feeding on plants) are difficult to predict without comprehensively describing prey-predator communities and their complex interplay. We sampled bird and arthropod communities in 30 oilseed rape fields in the spring of 2019 and 2020 in France. To assess the top-down control of arthropods by birds, we used a vertebrate exclusion experiment. Using a taxonomic and functional trait-based approach, we determined the direct and indirect influences of birds on arthropod predators and phytophagous insect populations in arable crops. We observed a negative relationship between the abundance of Carabidae and phytophagous insects but not with the other predator group suggesting the key role of Carabidae on phytophagous insects in agroecosystem. We found no statistical evidence of intraguild predation from birds toward intermediate predators. Despite the lack of overall effect of predator functional diversity on their prey, we highlighted the negative relationship between the functional complementarity (through functional evenness) of Carabidae and the abundance of phytophagous insects. This result suggests that functional complementarity between Carabidae species could help to reduce phytophagous insect populations. We analyzed the effect of agricultural practices on these multitrophic interactions, showing that pesticide intensity only had detrimental effects on Carabidae abundance, while the frequency of tillage did not affect the studied communities. Complementary indices used to depict communities are helpful to better understand the mechanisms underlying trophic relationships., Competing Interests: We declare no competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2021 The Authors. Ecology and Evolution published by John Wiley & Sons Ltd.)
- Published
- 2021
- Full Text
- View/download PDF
29. Any despot at my table? Competition among native and introduced bird species at garden birdfeeders in winter.
- Author
-
Deguines N, Lorrilliere R, Dozières A, Bessa-Gomes C, and Chiron F
- Subjects
- Animal Feed, Animals, Columbidae, Europe, Gardening, Seasons, Gardens, Introduced Species
- Abstract
Garden bird feeding constitutes a massive provision of food that can support bird communities, but there is a growing concern it might favour the establishment of exotic species that could be detrimental to others. How bird species compete with novel species for this anthropogenic food resources needs to be assessed. Here, we investigated competition in wintering bird communities at garden birdfeeders. We evaluated whether - and how much - bird access to resources is hampered by the presence of putative superior competing species, among which the Rose-ringed parakeet, the most abundant introduced species across Europe. Using the nation-wide citizen science scheme BirdLab, in which volunteers record in real-time bird attendance on a pair of birdfeeders during 5-minute sessions, we tested whether i) cumulative bird presence time and richness at birdfeeders, and ii) species probability of presence at birdfeeders, were influenced by three large species (the Eurasian magpie, the Eurasian collared-dove, and the Rose-ringed parakeet). Additionally, we assessed whether the Rose-ringed parakeet occupied resources significantly more than others. Presence of the Rose-ringed parakeet or the Eurasian collared-dove similarly reduced community cumulative presence time at birdfeeders, but only the dove reduced community richness. Each of the three large species influenced the presence of at least one of the six smaller species that could be separately modelled, but effects varied in strength and direction. The Rose-ringed parakeet and the Eurasian collared-dove were among the three species monopolising birdfeeders the longest, substantially more than the Eurasian magpie. Our findings confirm the competitive abilities of the large species studied, but do not suggest that garden bird feeding may alarmingly favour introduced species with detrimental effects on native species. Given the variability of large species' effects on small passerines, direct and indirect interactions among all species must be examined to fully understand the ecological net effects at stake., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier B.V. All rights reserved.)
- Published
- 2020
- Full Text
- View/download PDF
30. Effect of a 16-Day Altitude Training Camp on 3,000-m Steeplechase Running Energetics and Biomechanics: A Case Study.
- Author
-
Slawinski J, Chiron F, Millot B, Taouji A, and Brocherie F
- Abstract
The purpose of this study was to investigate the effect of a 16-day training camp at moderate altitude on running energetics and biomechanics in an elite female 3,000-m steeplechase athlete (personal best: 9 min 36.15 s). The 16-day intervention included living and training at 1,600 m altitude. A maximal incremental test was performed at sea level to determine the maximal oxygen uptake ( V ∙ O 2 max ). Before (pre-) and after (post-) intervention, the participant performed a specific training session consisting of 10 × 400 m with 5 hurdles with oxygen uptake ( V ∙ O 2 ), blood lactate, stride length and stride rate being measured. A video analysis determined take-off distance and landing around the hurdle (DT
H and DLH ), take-off velocity and landing around the hurdle (VTH and VLH ), and the maximal height over the hurdle (MH ). The results demonstrated that the mean V ∙ O 2 maintained during the ten 400 m trials represented 84-86% of V ∙ O 2 max and did not change from pre- to post-intervention ( p = 0.22). Mean blood lactate measured on the 6 last 400-m efforts increased significantly (12.0 ± 2.2 vs. 17.0 ± 1.6 mmol.l-1 ; p < 0.05). On the other hand, post-intervention maximal lactate decreased from 20.1 to 16.0 mmol.l-1 . Biomechanical analysis revealed that running velocity increased from 5.12 ± 0.16 to 5.49 ± 0.19 m.s-1 ( p < 0.001), concomitantly with stride length (1.63 ± 0.05 vs. 1.73 ± 0.06 m; p < 0.001). However, stride rate did not change (3.15 ± 0.03 vs. 3.16 ± 0.02 Hz; p = 0.14). While DTH was not significantly different from pre- to post- (1.34 ± 0.08 vs. 1.40 ± 0.07 m; p = 0.09), DLH was significantly longer (1.17 ± 0.07 vs. 1.36 ± 0.05 m; p < 0.01). VTH and VLH significantly improved after intervention (5.00 ± 0.14 vs. 5.33 ± 0.16 m.s- 1 and 5.18 ± 0.13 vs. 5.51 ± 0.22 m.s-1 , respectively; both p < 0.01). Finally, MH increased from pre- to post- (52.5 ± 3.8 vs. 54.9 ± 2.1 cm; p < 0.05). A 16-day moderate altitude training camp allowed an elite female 3,000-m steeplechase athlete to improve running velocity through a greater glycolytic-but not aerobic-metabolism., (Copyright © 2019 Slawinski, Chiron, Millot, Taouji and Brocherie.)- Published
- 2019
- Full Text
- View/download PDF
31. Tillage and herbicide reduction mitigate the gap between conventional and organic farming effects on foraging activity of insectivorous bats.
- Author
-
Barré K, Le Viol I, Julliard R, Chiron F, and Kerbiriou C
- Abstract
The increased use of pesticides and tillage intensification is known to negatively affect biodiversity. Changes in these agricultural practices such as herbicide and tillage reduction have variable effects among taxa, especially at the top of the trophic network including insectivorous bats. Very few studies compared the effects of agricultural practices on such taxa, and overall, only as a comparison of conventional versus organic farming without accurately accounting for underlying practices, especially in conventional where many alternatives exist. Divergent results founded in these previous studies could be driven by this lack of clarification about some unconsidered practices inside both conventional and organic systems. We simultaneously compared, over whole nights, bat activity on contiguous wheat fields of one organic and three conventional farming systems located in an intensive agricultural landscape. The studied organic fields (OT) used tillage (i.e., inversion of soil) without chemical inputs. In studied conventional fields, differences consisted of the following: tillage using few herbicides (T), conservation tillage (i.e., no inversion of soil) using few herbicides (CT), and conservation tillage using more herbicide (CTH), to control weeds. Using 64 recording sites (OT = 12; T = 21; CT = 13; CTH = 18), we sampled several sites per system placed inside the fields each night. We showed that bat activity was always higher in OT than in T systems for two ( Pipistrellus kuhlii and Pipistrellus pipistrellus ) of three species and for one ( Pipistrellus spp.) of two genera, as well as greater species richness. The same results were found for the CT versus T system comparison. CTH system showed higher activity than T for only one genus ( Pipistrellus spp.). We did not detect any differences between OT and CT systems, and CT showed higher activity than CTH system for only one species ( Pipistrellus kuhlii ). Activity in OT of Pipistrellus spp. was overall 3.6 and 9.3 times higher than CTH and T systems, respectively, and 6.9 times higher in CT than T systems. Our results highlight an important benefit of organic farming and contrasted effects in conventional farming. That there were no differences detected between the organic and one conventional system is a major result. This demonstrates that even if organic farming is presently difficult to implement and requires a change of economic context for farmers, considerable and easy improvements in conventional farming are attainable, while maintaining yields and approaching the ecological benefits of organic methods.
- Published
- 2017
- Full Text
- View/download PDF
32. Improving the selection of focal species exposed to pesticides to support ecological risk assessments.
- Author
-
Andrade C, Chiron F, and Julliard R
- Subjects
- Animals, Crops, Agricultural, Ecosystem, France, Birds physiology, Environmental Monitoring methods, Pesticides toxicity, Population Density, Risk Assessment methods
- Abstract
Risk assessment investigates the potential impacts of chemicals on non-target organisms. To assess the risk, ecotoxicologists study the responses of a panel of species to different substance exposure. Among the different parameters used to select indicator species (i.e. focal species), their frequency of occurrence is considered as the key parameter. Although species occurrence within a given habitat is easy to determine, we argue that it does not totally reflect the dependence of a species on a given habitat or its potential exposure to chemicals. In this study, we combined the occurrence of species with their habitat-specificity to identify focal species for risk assessment in cereals. We showed that ranking species by occurrence or by habitat-specificity produced different results, with generalist species ranking high in the occurrence list, and species with specialised habitats ranking high in the abundance list. Integrating frequency and abundance of species into one single indicator (the "Indicator Value") allows us to rank species with specialised habitats as high as generalist species in the top rank species list. Although habitat-specificity is an ecologically meaningful concept, it is largely overlooked in eco-toxicological risk assessment, despite the fact that specialists are good indicators of various environmental pressures. This method could be used extensively at different scales and could contribute to studies on risk assessment issue by (re)introducing ecological and population-level concepts and opening up new trait-based approaches.
- Published
- 2012
- Full Text
- View/download PDF
33. Disentangling the role of environmental and human pressures on biological invasions across Europe.
- Author
-
Pysek P, Jarosík V, Hulme PE, Kühn I, Wild J, Arianoutsou M, Bacher S, Chiron F, Didziulis V, Essl F, Genovesi P, Gherardi F, Hejda M, Kark S, Lambdon PW, Desprez-Loustau ML, Nentwig W, Pergl J, Poboljsaj K, Rabitsch W, Roques A, Roy DB, Shirley S, Solarz W, Vilà M, and Winter M
- Subjects
- Animals, Climate, Environment, Europe, Fungi growth & development, Geography, Humans, Invertebrates growth & development, Mammals growth & development, Models, Biological, Plant Development, Population Density, Population Dynamics, Regression Analysis, Biodiversity, Ecosystem, Human Activities
- Abstract
The accelerating rates of international trade, travel, and transport in the latter half of the twentieth century have led to the progressive mixing of biota from across the world and the number of species introduced to new regions continues to increase. The importance of biogeographic, climatic, economic, and demographic factors as drivers of this trend is increasingly being realized but as yet there is no consensus regarding their relative importance. Whereas little may be done to mitigate the effects of geography and climate on invasions, a wider range of options may exist to moderate the impacts of economic and demographic drivers. Here we use the most recent data available from Europe to partition between macroecological, economic, and demographic variables the variation in alien species richness of bryophytes, fungi, vascular plants, terrestrial insects, aquatic invertebrates, fish, amphibians, reptiles, birds, and mammals. Only national wealth and human population density were statistically significant predictors in the majority of models when analyzed jointly with climate, geography, and land cover. The economic and demographic variables reflect the intensity of human activities and integrate the effect of factors that directly determine the outcome of invasion such as propagule pressure, pathways of introduction, eutrophication, and the intensity of anthropogenic disturbance. The strong influence of economic and demographic variables on the levels of invasion by alien species demonstrates that future solutions to the problem of biological invasions at a national scale lie in mitigating the negative environmental consequences of human activities that generate wealth and by promoting more sustainable population growth.
- Published
- 2010
- Full Text
- View/download PDF
34. [Ocular tilt reaction in thalamic infarct].
- Author
-
Boleas-Aguirre MS and Chiron F
- Subjects
- Acute Disease, Aged, Brain Infarction complications, Diplopia etiology, Eye Diseases physiopathology, Female, Hearing Loss, Bilateral complications, Hearing Loss, Sensorineural complications, Humans, Hypercholesterolemia complications, Hypertension complications, Ischemic Attack, Transient complications, Magnetic Resonance Imaging, Nystagmus, Pathologic etiology, Ocular Motility Disorders physiopathology, Otolithic Membrane physiopathology, Paresis etiology, Torsion Abnormality physiopathology, Vestibular Function Tests, Brain Infarction physiopathology, Eye Diseases etiology, Ocular Motility Disorders etiology, Thalamus blood supply, Torsion Abnormality etiology, Vertigo etiology
- Abstract
Ocular tilt reaction (OTR) includes skew deviation, eye torsion and head tilt. It is usually accompanied by a tilt in the subjective visual vertical. OTR seems to reflect an otolithic dysfunction. This case report shows an OTR of central origin as a result of simultaneous paramedial thalamic and mesencephalon rostral infarcts.
- Published
- 2009
- Full Text
- View/download PDF
35. Human-related processes drive the richness of exotic birds in Europe.
- Author
-
Chiron F, Shirley S, and Kark S
- Subjects
- Animals, Behavior, Animal, Europe, Geography, Humans, Population Density, Population Dynamics, Biodiversity, Birds physiology, Environment
- Abstract
Both human-related and natural factors can affect the establishment and distribution of exotic species. Understanding the relative role of the different factors has important scientific and applied implications. Here, we examined the relative effect of human-related and natural factors in determining the richness of exotic bird species established across Europe. Using hierarchical partitioning, which controls for covariation among factors, we show that the most important factor is the human-related community-level propagule pressure (the number of exotic species introduced), which is often not included in invasion studies due to the lack of information for this early stage in the invasion process. Another, though less important, factor was the human footprint (an index that includes human population size, land use and infrastructure). Biotic and abiotic factors of the environment were of minor importance in shaping the number of established birds when tested at a European extent using 50 x 50 km2 grid squares. We provide, to our knowledge, the first map of the distribution of exotic bird richness in Europe. The richest hotspot of established exotic birds is located in southeastern England, followed by areas in Belgium and The Netherlands. Community-level propagule pressure remains the major factor shaping the distribution of exotic birds also when tested for the UK separately. Thus, studies examining the patterns of establishment should aim at collecting the crucial and hard-to-find information on community-level propagule pressure or develop reliable surrogates for estimating this factor. Allowing future introductions of exotic birds into Europe should be reconsidered carefully, as the number of introduced species is basically the main factor that determines the number established.
- Published
- 2009
- Full Text
- View/download PDF
36. [Probable speciations by "host-vector 'fidelity'": 14 species of Plasmodium from magpies].
- Author
-
Chavatte JM, Chiron F, Chabaud A, and Landau I
- Subjects
- Animals, Host-Parasite Interactions, Insect Vectors parasitology, Species Specificity, Aedes parasitology, Bird Diseases parasitology, Phylogeny, Plasmodium classification, Plasmodium isolation & purification, Songbirds
- Abstract
33 Magpies resident in two parks close to Paris were investigated for the presence of Plasmodium parasites. The majority of the birds were found to be infected with multiple parasite species. A total of 14 species were observed, and of these 10 were novel and consequently described, and two could not be assigned with confidence. It is hypothesized that the unexpected abundance of species is due to a phenomenon which we term "host-vector 'fidelisation'". Indeed, the combination of the eco-biological characteristics of the host (mating pairs in contiguous, but strictly defined territories) with those of the vector (numerous Aedes species with distinct behavior), would generate fragmentation of the niches. This type of isolation overlays others known for parasitic populations (geographical, circadian, microlocalisations), leading to the formation of independent host-parasite niches which in turn lead to speciation.
- Published
- 2007
- Full Text
- View/download PDF
Catalog
Discovery Service for Jio Institute Digital Library
For full access to our library's resources, please sign in.