Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 157
Filtrar
Más filtros

Tipo del documento
Intervalo de año de publicación
1.
J Neurophysiol ; 131(2): 137-151, 2024 Feb 01.
Artículo en Inglés | MEDLINE | ID: mdl-38150542

RESUMEN

The Drosophila neuropeptide, DPKQDFMRFamide, was previously shown to enhance excitatory junctional potentials (EJPs) and muscle contraction by both presynaptic and postsynaptic actions. Since the peptide acts on both sides of the synaptic cleft, it has been difficult to examine postsynaptic modulatory mechanisms, particularly when contractions are elicited by nerve stimulation. Here, postsynaptic actions are examined in 3rd instar larvae by applying peptide and the excitatory neurotransmitter, l-glutamate, in the bathing solution to elicit contractions after silencing motor output by removing the central nervous system (CNS). DPKQDFMRFamide enhanced glutamate-evoked contractions at low concentrations (EC50 1.3 nM), consistent with its role as a neurohormone, and the combined effect of both substances was supra-additive. Glutamate-evoked contractions were also enhanced when transmitter release was blocked in temperature-sensitive (Shibire) mutants, confirming the peptide's postsynaptic action. The peptide increased membrane depolarization in muscle when co-applied with glutamate, and its effects were blocked by nifedipine, an L-type channel blocker, indicating effects at the plasma membrane involving calcium influx. DPKQDFMRFamide also enhanced contractions induced by caffeine in the absence of extracellular calcium, suggesting increased calcium release from the sarcoplasmic reticulum (SR) or effects downstream of calcium release from the SR. The peptide's effects do not appear to involve calcium/calmodulin-dependent protein kinase II (CaMKII), previously shown to mediate presynaptic effects. The approach used here might be useful for examining postsynaptic effects of neurohormones and cotransmitters in other systems.NEW & NOTEWORTHY Distinguishing presynaptic and postsynaptic effects of neurohormones is a long-standing challenge in many model organisms. Here, postsynaptic actions of DPKQDFMRFamide are demonstrated by assessing its ability to potentiate contractions elicited by direct application of the neurotransmitter, glutamate, when axons are silent and when transmitter release is blocked. The peptide acts at multiple sites to increase contraction, increasing glutamate-induced depolarization at the cell membrane, acting on L-type channels, and acting downstream of calcium release from the sarcoplasmic reticulum.


Asunto(s)
Drosophila , Neuropéptidos , Animales , Drosophila/metabolismo , Unión Neuromuscular/fisiología , Calcio , Neuropéptidos/farmacología , Contracción Muscular , Péptidos/farmacología , Proteína Quinasa Tipo 2 Dependiente de Calcio Calmodulina/metabolismo , Glutamatos , Neurotransmisores/farmacología
2.
Eur J Clin Microbiol Infect Dis ; 43(2): 355-371, 2024 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-38099986

RESUMEN

PURPOSE: A new high-resolution next-generation sequencing (NGS)-based method was established to type closely related European type II Toxoplasma gondii strains. METHODS: T. gondii field isolates were collected from different parts of Europe and assessed by whole genome sequencing (WGS). In comparison to ME49 (a type II reference strain), highly polymorphic regions (HPRs) were identified, showing a considerable number of single nucleotide polymorphisms (SNPs). After confirmation by Sanger sequencing, 18 HPRs were used to design a primer panel for multiplex PCR to establish a multilocus Ion AmpliSeq typing method. Toxoplasma gondii isolates and T. gondii present in clinical samples were typed with the new method. The sensitivity of the method was tested with serially diluted reference DNA samples. RESULTS: Among type II specimens, the method could differentiate the same number of haplotypes as the reference standard, microsatellite (MS) typing. Passages of the same isolates and specimens originating from abortion outbreaks were identified as identical. In addition, seven different genotypes, two atypical and two recombinant specimens were clearly distinguished from each other by the method. Furthermore, almost all SNPs detected by the Ion AmpliSeq method corresponded to those expected based on WGS. By testing serially diluted DNA samples, the method exhibited a similar analytical sensitivity as MS typing. CONCLUSION: The new method can distinguish different T. gondii genotypes and detect intra-genotype variability among European type II T. gondii strains. Furthermore, with WGS data additional target regions can be added to the method to potentially increase typing resolution.


Asunto(s)
Toxoplasma , Embarazo , Femenino , Humanos , Toxoplasma/genética , Genotipo , Reacción en Cadena de la Polimerasa Multiplex , Secuenciación de Nucleótidos de Alto Rendimiento , ADN Protozoario/genética , Variación Genética , Polimorfismo de Longitud del Fragmento de Restricción
3.
Eur J Clin Microbiol Infect Dis ; 42(7): 803-818, 2023 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-37093325

RESUMEN

A ring trial among five European laboratories was organized to reach consistency in microsatellite (MS) typing of the zoonotic parasite Toxoplasma gondii. Three sample sets were circulated and analyzed by each laboratory following a previously published method that is based on fragment length polymorphism of 15 MS markers. The first sample set compared typing results in general and focused on effects of DNA concentration; the second sample set focused on the polymorphic fingerprinting markers that can differentiate T. gondii strains within the same archetypal lineage; and the third set focused on non-archetypal genotypes. Methodological variations between laboratories, including the software programs used to determine MS fragment length, were collated using a questionnaire. Overall, lineage-level typing results reached a high level of agreement, especially in samples with the highest DNA concentrations. However, laboratory-specific differences were observed for particular markers. Major median differences in fragment length, of up to 6 base pairs, were related to the fluorophore used to label fragment-specific primers. In addition, primer pairs with identical sequences obtained from different suppliers resulted in fragments of differing length. Furthermore, differences in the way the sequencing profiles were assessed and interpreted may have led to deviating results in fragment length determination. Harmonization of MS typing, for example, by using the same fluorophores or by numerical adjustments applied to the fragment-lengths determined, could improve the uniformity of the results across laboratories. This is the first interlaboratory comparison, providing guidelines (added as a supplement) for the optimization of this technique.


Asunto(s)
Toxoplasma , Toxoplasmosis Animal , Humanos , Animales , Toxoplasma/genética , Variación Genética , Polimorfismo de Longitud del Fragmento de Restricción , ADN Protozoario/genética , Repeticiones de Microsatélite , Genotipo
4.
Rev Sci Tech ; 39(3): 805-815, 2020 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-35275132

RESUMEN

In a context of globalisation and climate change, the risk of emerging infectious diseases spreading around the world has significantly increased in the past decades. In response to this growing threat, an epidemic intelligence team has been set up within the framework of the French animal health epidemiological surveillance platform (ESA platform). The French Epidemic Intelligence System (FEIS) monitors animal health risks in Europe and beyond that threaten animal populations in France (emerging and exotic diseases not yet present). The FEIS expert network covers all 53 category 1 health hazards identified as priority diseases by the French authorities. From January 2016 to December 2017, the FEIS published 126 reports on animal health events related to infectious diseases, of which 76.2% were related to events in Europe. When comparing FEIS reports to posts from the Program for Monitoring Emerging Diseases (ProMED), an FEIS report was produced for 52.6% of ProMED themes (combinations of disease and country) posted in 2016-2017 on events in Europe. The remaining European ProMED themes did not meet the criterion for the production of an FEIS report because either the disease was already present in France, the risk of introduction into France was considered low or negligible, or the introduction of the pathogen would have low or negligible economic and societal impacts. The FEIS efficiently detected and reported on all health hazards identified by ProMED to alert health authorities and stakeholders when needed (according to the criterion). Compared with international epidemic intelligence systems such as ProMED, which provide general information, the FEIS adds another layer of filtering and interpretation to available information on animal health threats tailored to France's specific needs, in order to communicate only essential information to health authorities.


Dans un contexte caractérisé par la mondialisation et le changement climatique, le risque de propagation mondiale des maladies infectieuses émergentes s'est significativement accru en quelques décennies. Pour répondre à cette menace croissante, une équipe de veille épidémique a été mise en place dans le cadre de la Plateforme française d'épidémiosurveillance en santé animale (Plateforme ESA). Le système de Veille sanitaire internationale (VSI) surveille les risques sanitaires en santé animale présents en Europe, voire au-delà, dès lors qu'ils représentent une menace pour les populations animales sur le territoire français (maladies émergentes et maladies exotiques jamais introduites en France). Le réseau d'experts de la VSI couvre les 53 risques sanitaires de catégorie 1 définis par les autorités françaises comme maladies prioritaires. De janvier 2016 à décembre 2017, 126 rapports de la VSI ont été publiés sur des événements de santé animale liés à des maladies infectieuses, dont 76,2 % concernaient des événements survenus en Europe. La comparaison entre les rapports émanant de la VSI et ceux du Programme de suivi des maladies émergentes (ProMED) fait apparaître que 52,6 % des thématiques publiées en 2016-2017 par ProMED (associant une maladie et un pays) relatives à des événements survenus en Europe avaient également fait l'objet d'un rapport par la VSI. Les thématiques restantes sur ProMED correspondant à des événements européens ne répondaient pas aux critères de la VSI, soit parce qu'il s'agissait d'une maladie déjà présente en France, soit parce que le risque d'introduction de l'agent pathogène en France était considéré comme faible ou négligeable, soit enfin parce que l'impact économique et sociétal d'une telle introduction, si elle survenait, aurait été faible ou négligeable. La VSI a détecté (en fonction de ses critères) l'ensemble des risques sanitaires identifiés par ProMED et les a notifiés avec efficacité aux autorités et acteurs en charge de la santé, chaque fois que nécessaire. Par rapport aux systèmes de veille sanitaire internationaux tels que ProMED qui fournissent des informations générales, la VSI, qui est spécifiquement adaptée aux besoins français, ajoute une strate supplémentaire de filtrage et d'interprétation des données disponibles sur les menaces de santé animale, afin de ne transmettre aux autorités sanitaires que les informations qui leur sont essentielles.


De unos decenios a esta parte, en un contexto marcado por la mundialización y el cambio climático, ha aumentado sustancialmente el riesgo de propagación por todo el mundo de enfermedades infecciosas emergentes. Para responder a esta creciente amenaza se ha establecido, dentro del dispositivo francés de vigilancia epidemiológica zoosanitaria (plataforma ESA), un equipo de inteligencia epidemiológica. El Sistema Francés de Información Epidemiológica (épidémiologique) está dedicado a seguir de cerca los riesgos zoosanitarios que, desde Europa u otras partes del mundo, amenacen a las poblaciones animales de Francia (enfermedades emergentes y exóticas que aún no estén presentes en el país). La red de especialistas de la VSI cubre la totalidad de los 53 peligros sanitarios de categoría 1 que las autoridades francesas tienen definidos como enfermedades prioritarias. Entre enero de 2016 y diciembre de 2017, la VSI publicó 126 informes sobre episodios zoosanitarios relacionados con enfermedades infecciosas, de los que un 76,2% tenían que ver con episodios ocurridos en Europa. Al comparar los informes de la VSI con las notas publicadas por el Programa de Vigilancia de Enfermedades Emergentes (ProMED) se constató que ela VSI había elaborado un informe en relación con el 52,6% de los temas (combinación de enfermedades y países) tratados por el ProMED en sus notas de 2016 y 2017 sobre episodios ocurridos en suelo europeo. Los restantes temas europeos tratados por el ProMED no cumplían el criterio de que hubiera un informe de la VSI al respecto, ya fuera porque la enfermedad ya estaba presente en Francia, porque se consideró bajo o insignificante el riesgo de penetración en Francia o porque la llegada del patógeno tendría una repercusión escasa o insignificante en la economía o la sociedad. La VSI detectó y comunicó con eficacia todos los peligros sanitarios identificados por el ProMED para alertar a las autoridades sanitarias y demás interlocutores cada vez que fue necesario (con arreglo al criterio). En comparación con los sistemas internacionales de información epidemiológica, como el ProMED, que proporcionan información general, la VSI agrega un filtro y un nivel de interpretación suplementarios a la información disponible sobre amenazas zoosanitarias, adaptándola así a las necesidades específicas de Francia, con el fin de comunicar únicamente información esencial a las autoridades sanitarias.

5.
J Neurogenet ; 32(3): 183-194, 2018 09.
Artículo en Inglés | MEDLINE | ID: mdl-30303434

RESUMEN

Over the past four decades, Drosophila melanogaster has become an increasingly important model system for studying the modulation of chemical synapses and muscle contraction by cotransmitters and neurohormones. This review describes how advantages provided by Drosophila have been utilized to investigate synaptic modulation, and it discusses key findings from investigations of cotransmitters and neurohormones that act on body wall muscles of 3rd instar Drosophila larvae. These studies have contributed much to our understanding of how neuromuscular systems are modulated by neuropeptides and biogenic amines, but there are still gaps in relating these peripheral modulatory effects to behavior.


Asunto(s)
Drosophila melanogaster/fisiología , Contracción Muscular/fisiología , Unión Neuromuscular/fisiología , Transmisión Sináptica/fisiología , Animales , Larva , Neuropéptidos/fisiología , Neurotransmisores/fisiología
6.
Handb Exp Pharmacol ; 246: 125-145, 2018.
Artículo en Inglés | MEDLINE | ID: mdl-28939974

RESUMEN

Voltage-gated sodium channels (VGSC) are critical determinants of cellular electrical activity through the control of initiation and propagation of action potential. To ensure this role, these proteins are not consistently delivered to the plasma membrane but undergo drastic quality controls throughout various adaptive processes such as biosynthesis, anterograde and retrograde trafficking, and membrane targeting. In pathological conditions, this quality control could lead to the retention of functional VGSC and is therefore the target of different pharmacological approaches. The present chapter gives an overview of the current understanding of the facets of VGSC life cycle in the context of both cardiac and neuronal cell types.


Asunto(s)
Canales de Sodio Activados por Voltaje/metabolismo , Animales , Retículo Endoplásmico/metabolismo , Aparato de Golgi/metabolismo , Humanos , Multimerización de Proteína , Transporte de Proteínas
7.
Adv Mar Biol ; 76: 41-104, 2017.
Artículo en Inglés | MEDLINE | ID: mdl-28065296

RESUMEN

Egg pigmentation is proposed to serve numerous ecological, physiological, and adaptive functions in egg-laying animals. Despite the predominance and taxonomic diversity of egg layers, syntheses reviewing the putative functions and drivers of egg pigmentation have been relatively narrow in scope, centring almost exclusively on birds. Nonvertebrate and aquatic species are essentially overlooked, yet many of them produce maternally provisioned eggs in strikingly varied colours, from pale yellow to bright red or green. We explore the ways in which these colour patterns correlate with behavioural, morphological, geographic and phylogenetic variables in extant classes of Echinodermata, a phylum that has close phylogenetic ties with chordates and representatives in nearly all marine environments. Results of multivariate analyses show that intensely pigmented eggs are characteristic of pelagic or external development whereas pale eggs are commonly brooded internally. Of the five egg colours catalogued, orange and yellow are the most common. Yellow eggs are a primitive character, associated with all types of development (predominant in internal brooders), whereas green eggs are always pelagic, occur in the most derived orders of each class and are restricted to the Indo-Pacific Ocean. Orange eggs are geographically ubiquitous and may represent a 'universal' egg pigment that functions well under a diversity of environmental conditions. Finally, green occurs chiefly in the classes Holothuroidea and Ophiuroidea, orange in Asteroidea, yellow in Echinoidea, and brown in Holothuroidea. By examining an unprecedented combination of egg colours/intensities and reproductive strategies, this phylum-wide study sheds new light on the role and drivers of egg pigmentation, drawing parallels with theories developed from the study of more derived vertebrate taxa. The primary use of pigments (of any colour) to protect externally developing eggs from oxidative damage and predation is supported by the comparatively pale colour of equally large, internally brooded eggs. Secondarily, geographic location drives the evolution of egg colour diversity, presumably through the selection of better-adapted, more costly pigments in response to ecological pressure.


Asunto(s)
Equinodermos/fisiología , Óvulo/fisiología , Pigmentos Biológicos/fisiología , Animales , Biodiversidad , Océanos y Mares , Especificidad de la Especie
8.
J Neurophysiol ; 115(1): 568-80, 2016 Jan 01.
Artículo en Inglés | MEDLINE | ID: mdl-26538605

RESUMEN

The neuropeptide proctolin (RYLPT) plays important roles as both a neurohormone and a cotransmitter in arthropod neuromuscular systems. We used third-instar Drosophila larvae as a model system to differentiate synaptic effects of this peptide from its direct effects on muscle contractility and to determine whether proctolin can work in a cell-selective manner on muscle fibers. Proctolin did not appear to alter the amplitude of excitatory junctional potentials but did induce sustained muscle contractions in preparations where the CNS had been removed and no stimuli were applied to the remaining nerves. Proctolin-induced contractions were dose-dependent, were reduced by knocking down expression of the Drosophila proctolin receptor in muscle tissue, and were larger in some muscle cells than others (i.e., larger in fibers 4, 12, and 13 than in 6 and 7). Proctolin also increased the amplitude of nerve-evoked contractions in a dose-dependent manner, and the magnitude of this effect was also larger in some muscle cells than others (again, larger in fibers 4, 12, and 13 than in 6 and 7). Increasing the intraburst impulse frequency and number of impulses per burst increased the magnitude of proctolin's enhancement of nerve-evoked contractions and decreased the threshold and EC50 concentrations for proctolin to enhance nerve-evoked contractions. Reducing proctolin receptor expression decreased the velocity of larval crawling at higher temperatures, and thermal preference in these larvae. Our results suggest that proctolin acts directly on body-wall muscles to elicit slow, sustained contractions and to enhance nerve-evoked contractions, and that proctolin affects muscle fibers in a cell-selective manner.


Asunto(s)
Drosophila melanogaster/fisiología , Proteínas de Insectos/fisiología , Células Musculares/fisiología , Contracción Muscular/efectos de los fármacos , Unión Neuromuscular/fisiología , Neuropéptidos/fisiología , Oligopéptidos/fisiología , Animales , Larva , Unión Neuromuscular/efectos de los fármacos , Neuropéptidos/administración & dosificación , Neurotransmisores/administración & dosificación , Oligopéptidos/administración & dosificación
9.
Eur J Cancer Care (Engl) ; 25(1): 18-26, 2016 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-25851842

RESUMEN

Colorectal cancer (CRC) mass screening has been implemented in France since 2008. Participation rates remain too low. The objective of this study was to test if the implementation of a training course focused on communication skills among general practitioners (GP) would increase the delivery of gaiac faecal occult blood test and CRC screening participation among the target population of each participating GP. A cluster randomised controlled trial was conducted with GP's practice as a cluster unit. GPs from practices in the control group were asked to continue their usual care. GPs of the intervention group received a 4-h educational training, built with previous qualitative data on CRC screening focusing on doctor-patient communication with a follow-up of 7 months for both groups. The primary outcome measure was the patients' participation rate in the target population for each GP. Seventeen GPs (16 practices) in intervention group and 28 GPs (19 practices) in control group participated. The patients' participation rate in the intervention group were 36.7% vs. 24.5% in the control group (P = 0.03). Doctor-patient communication should be developed and appear to be one of the possible targets of improvement patients adherence and participation rate in the target population for CRC mass screening.


Asunto(s)
Neoplasias Colorrectales/diagnóstico , Comunicación , Detección Precoz del Cáncer , Educación Profesional/métodos , Medicina Familiar y Comunitaria , Relaciones Médico-Paciente , Adulto , Análisis por Conglomerados , Medicina Familiar y Comunitaria/estadística & datos numéricos , Femenino , Francia , Humanos , Masculino , Tamizaje Masivo/métodos , Tamizaje Masivo/estadística & datos numéricos , Persona de Mediana Edad , Sangre Oculta , Evaluación de Resultado en la Atención de Salud , Participación del Paciente/estadística & datos numéricos , Atención Dirigida al Paciente/normas , Pautas de la Práctica en Medicina/estadística & datos numéricos
10.
J Neurophysiol ; 113(5): 1631-43, 2015 Mar 01.
Artículo en Inglés | MEDLINE | ID: mdl-25520433

RESUMEN

Neuropeptides can modulate physiological properties of neurons in a cell-specific manner. The present work examines whether a neuropeptide can also modulate muscle tissue in a cell-specific manner using identified muscle cells in third-instar larvae of fruit flies. DPKQDFMRFa, a modulatory peptide in the fruit fly Drosophila melanogaster, has been shown to enhance transmitter release from motor neurons and to elicit contractions by a direct effect on muscle cells. We report that DPKQDFMRFa causes a nifedipine-sensitive drop in input resistance in some muscle cells (6 and 7) but not others (12 and 13). The peptide also increased the amplitude of nerve-evoked contractions and compound excitatory junctional potentials (EJPs) to a greater degree in muscle cells 6 and 7 than 12 and 13. Knocking down FMRFamide receptor (FR) expression separately in nerve and muscle indicate that both presynaptic and postsynaptic FR expression contributed to the enhanced contractions, but EJP enhancement was mainly due to presynaptic expression. Muscle ablation showed that DPKQDFMRFa induced contractions and enhanced nerve-evoked contractions more strongly in muscle cells 6 and 7 than cells 12 and 13. In situ hybridization indicated that FR expression was significantly greater in muscle cells 6 and 7 than 12 and 13. Taken together, these results indicate that DPKQDFMRFa can elicit cell-selective effects on muscle fibers. The ability of neuropeptides to work in a cell-selective manner on neurons and muscle cells may help explain why so many peptides are encoded in invertebrate and vertebrate genomes.


Asunto(s)
Drosophila melanogaster/fisiología , FMRFamida/farmacología , Fibras Musculares Esqueléticas/efectos de los fármacos , Unión Neuromuscular/efectos de los fármacos , Neuropéptidos/farmacología , Precursores de Proteínas/farmacología , Animales , Potenciales Postsinápticos Excitadores , Contracción Muscular , Fibras Musculares Esqueléticas/fisiología , Unión Neuromuscular/fisiología , Nifedipino/farmacología
11.
J Appl Microbiol ; 118(5): 1238-49, 2015 May.
Artículo en Inglés | MEDLINE | ID: mdl-25727794

RESUMEN

AIMS: To develop a rapid and sensitive method to quantify viable Legionella spp. in cooling tower water samples. METHODS AND RESULTS: A rapid, culture-based method capable of quantifying as few as 600 Legionella microcolonies per litre within 2 days in industrial waters was developed. The method combines a short cultivation step of microcolonies on GVPC agar plate, specific detection of Legionella cells by a fluorescent in situ hybridization (FISH) approach, and a sensitive enumeration using a solid-phase cytometer. Following optimization of the cultivation conditions, the qualitative and quantitative performance of the method was assessed and the method was applied to 262 nuclear power plant cooling water samples. CONCLUSIONS: The performance of this method was in accordance with the culture method (NF-T 90-431) for Legionella enumeration. SIGNIFICANCE AND IMPACT OF THE STUDY: The rapid detection of viable Legionella in water is a major concern to the effective monitoring of this pathogenic bacterium in the main water sources involved in the transmission of legionellosis infection (Legionnaires' disease). The new method proposed here appears to be a robust, efficient and innovative means for rapidly quantifying cultivable Legionella in cooling tower water samples within 48 h.


Asunto(s)
Citometría de Flujo/métodos , Agua Dulce/microbiología , Hibridación Fluorescente in Situ/métodos , Legionella/aislamiento & purificación , Enfermedad de los Legionarios/microbiología , Plantas de Energía Nuclear/instrumentación , Humanos , Legionella/citología , Legionella/genética , Legionella/crecimiento & desarrollo , Enfermedad de los Legionarios/prevención & control , Microbiología del Agua
12.
Cult Med Psychiatry ; 39(1): 43-61, 2015 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-25304396

RESUMEN

This study of comments posted on major French print and TV media websites during the H1N1 epidemic illustrates the relationship between the traditional media and social media in responding to an emerging disease. A disturbing "geography of blame" was observed suggesting the metamorphosis of the folk-devil phenomenon to the Internet. We discovered a subterranean discourse about the putative origins and "objectives" of the H1N1 virus, which was absent from the discussions in mainstream television channels and large-circulation print media. These online rumours attributed hidden motives to governments, pharmaceutical companies, and figures of Otherness that were scapegoated in the social history of previous European epidemics, notably Freemasons and Jews.


Asunto(s)
Información de Salud al Consumidor/métodos , Epidemias , Subtipo H1N1 del Virus de la Influenza A , Gripe Humana , Vacunación Masiva , Opinión Pública , Acceso a la Información , Francia/epidemiología , Humanos , Gripe Humana/epidemiología , Gripe Humana/prevención & control , Gripe Humana/psicología , Medios de Comunicación de Masas/normas , Vacunación Masiva/organización & administración , Vacunación Masiva/psicología , Quebec/epidemiología , Medios de Comunicación Sociales/normas , Percepción Social
13.
J Exp Biol ; 217(Pt 10): 1725-36, 2014 May 15.
Artículo en Inglés | MEDLINE | ID: mdl-24526728

RESUMEN

Drosophila melanogaster is a model system for examining the mechanisms of action of neuropeptides. DPKQDFMRFamide was previously shown to induce contractions in Drosophila body wall muscle fibres in a Ca(2+)-dependent manner. The present study examined the possible involvement of a G-protein-coupled receptor and second messengers in mediating this myotropic effect after removal of the central nervous system. DPKQDFMRFamide-induced contractions were reduced by 70% and 90%, respectively, in larvae with reduced expression of the Drosophila Fmrf receptor (FR) either ubiquitously or specifically in muscle tissue, compared with the response in control larvae in which expression was not manipulated. No such effect occurred in larvae with reduced expression of this gene only in neurons. The myogenic effects of DPKQDFMRFamide do not appear to be mediated through either of the two Drosophila myosuppressin receptors (DmsR-1 and DmsR-2). DPKQDFMRFamide-induced contractions were not reduced in Ala1 transgenic flies lacking activity of calcium/calmodulin-dependent protein kinase (CamKII), and were not affected by the CaMKII inhibitor KN-93. Peptide-induced contractions in the mutants of the phospholipase C-ß (PLCß) gene (norpA larvae) and in IP3 receptor mutants were similar to contractions elicited in control larvae. The peptide failed to increase cAMP and cGMP levels in Drosophila body wall muscles. Peptide-induced contractions were not potentiated by 3-isobutyl-1-methylxanthine, a phosphodiesterase inhibitor, and were not antagonized by inhibitors of cAMP-dependent or cGMP-dependent protein kinases. Additionally, exogenous application of arachidonic acid failed to induce myogenic contractions. Thus, DPKQDFMRFamide induces contractions via a G-protein coupled FMRFamide receptor in muscle cells but does not appear to act via cAMP, cGMP, IP3, PLC, CaMKII or arachidonic acid.


Asunto(s)
Proteínas de Drosophila/metabolismo , Drosophila melanogaster/fisiología , FMRFamida/metabolismo , Precursores de Proteínas/metabolismo , Receptores de Péptidos de Invertebrados/metabolismo , Animales , Ácido Araquidónico/metabolismo , Proteína Quinasa Tipo 2 Dependiente de Calcio Calmodulina/metabolismo , AMP Cíclico/metabolismo , GMP Cíclico/metabolismo , Contracción Muscular , Fosfolipasas de Tipo C/metabolismo
14.
J Neurophysiol ; 110(8): 1984-96, 2013 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-23904495

RESUMEN

Octopamine (OA) and tyramine (TA) play important roles in homeostatic mechanisms, behavior, and modulation of neuromuscular junctions in arthropods. However, direct actions of these amines on muscle force production that are distinct from effects at the neuromuscular synapse have not been well studied. We utilize the technical benefits of the Drosophila larval preparation to distinguish the effects of OA and TA on the neuromuscular synapse from their effects on contractility of muscle cells. In contrast to the slight and often insignificant effects of TA, the action of OA was profound across all metrics assessed. We demonstrate that exogenous OA application decreases the input resistance of larval muscle fibers, increases the amplitude of excitatory junction potentials (EJPs), augments contraction force and duration, and at higher concentrations (10(-5) and 10(-4) M) affects muscle cells 12 and 13 more than muscle cells 6 and 7. Similarly, OA increases the force of synaptically driven contractions in a cell-specific manner. Moreover, such augmentation of contractile force persisted during direct muscle depolarization concurrent with synaptic block. OA elicited an even more profound effect on basal tonus. Application of 10(-5) M OA increased synaptically driven contractions by ≈ 1.1 mN but gave rise to a 28-mN increase in basal tonus in the absence of synaptic activation. Augmentation of basal tonus exceeded any physiological stimulation paradigm and can potentially be explained by changes in intramuscular protein mechanics. Thus we provide evidence for independent but complementary effects of OA on chemical synapses and muscle contractility.


Asunto(s)
Drosophila melanogaster/fisiología , Músculo Esquelético/efectos de los fármacos , Unión Neuromuscular/efectos de los fármacos , Octopamina/farmacología , Tiramina/farmacología , Animales , Larva/fisiología , Potenciales de la Membrana , Contracción Muscular , Músculo Esquelético/fisiología , Unión Neuromuscular/fisiología
15.
J Exp Biol ; 215(Pt 11): 1892-904, 2012 Jun 01.
Artículo en Inglés | MEDLINE | ID: mdl-22573768

RESUMEN

An unequal resource distribution is commonly seen in dominance hierarchies, in which the individual with the higher status is more successful in obtaining the resource. One possible resource is preferred temperature. When situations allow, ectotherms regulate their body temperature by behaviourally selecting different environmental conditions, achieving, when possible, a preferred temperature. Using a shuttlebox, the preferred temperature for Procambarus clarkii was determined to be 23.9°C with upper and lower voluntary escape temperatures of 25.9 and 21.8°C, respectively. If this preferred temperature zone (21.8-25.9°C) was valued as a resource, given the choice between a preferred temperature and a non-preferred temperature, crayfish should compete over the preferred temperature, with the dominant individual of dyadic pairs achieving the preferred temperature more often than the subordinate. Using a dual-choice experimental tank, competition over a binary temperature choice between rank-established paired crayfish was determined under both warm and cold challenge conditions (warm vs preferred temperature and cold vs preferred temperature, respectively). In naive pairings, similar levels of competition over the preferred temperature occurred in both warm and cold challenge trials, as predicted by game theory. In established pairings, however, dominant crayfish gained significantly greater access to preferred temperature in both warm and cold challenge conditions. These results demonstrate that crayfish engage in a cost-benefit assessment during their initial agonistic contests over temperature, but as hierarchies mature, these thermal games are decided by the dominant animal gaining primary access to the temperature resource.


Asunto(s)
Astacoidea/fisiología , Conducta Agonística/fisiología , Animales , Conducta Animal/fisiología , Regulación de la Temperatura Corporal/fisiología , Ambiente , Teoría del Juego , Habituación Psicofisiológica/fisiología , Jerarquia Social , Modelos Biológicos , Conducta Social , Temperatura
16.
Parasite ; 19(2): 177-82, 2012 May.
Artículo en Inglés | MEDLINE | ID: mdl-22550630

RESUMEN

A total of 134 Egyptian liver flukes were collected from different definitive hosts (cattle, sheep, and buffaloes) to identify them via the use of PCR-RFLP and sequence analysis of the first nuclear ribosomal internal transcribed spacer (ITS1). Specimens of F. hepatica from France, as well as F. gigantica from Cameroon were included in the study for comparison. PCR products of ITS1 were subjected for digestion by RsaI restriction enzyme and visualized on agarose gel. According to RFLP pattern, Egyptian flukes were allocated into two categories. The first was identical to that of French hepatica flukes to have a pattern of 360, 100, and 60 (bp) band size, whereas the second resembled to that of Cameroonian gigantica worms to have a profile of 360, 170, and 60 bp in size. Results of RFLP analysis were confirmed by sequence analysis of representative ITS1 amplicons. No hybrid forms were detected in the present study. Taken together, this study concluded that both species of Fasciola are present in Egypt, whereas the hybrid form may be not very common.


Asunto(s)
Búfalos/parasitología , Enfermedades de los Bovinos/epidemiología , Fasciola/aislamiento & purificación , Fascioliasis/veterinaria , Enfermedades de las Ovejas/epidemiología , Animales , Secuencia de Bases , Bovinos , Enfermedades de los Bovinos/parasitología , ADN de Helmintos/química , Desoxirribonucleasas de Localización Especificada Tipo II , Egipto/epidemiología , Electroforesis en Gel de Agar/veterinaria , Fasciola/clasificación , Fasciola/genética , Fascioliasis/epidemiología , Fascioliasis/parasitología , Datos de Secuencia Molecular , Reacción en Cadena de la Polimerasa/métodos , Reacción en Cadena de la Polimerasa/veterinaria , Polimorfismo de Longitud del Fragmento de Restricción , Mapeo Restrictivo/veterinaria , Alineación de Secuencia , Ovinos , Enfermedades de las Ovejas/parasitología
17.
J Neurosci ; 30(44): 14724-34, 2010 Nov 03.
Artículo en Inglés | MEDLINE | ID: mdl-21048131

RESUMEN

Neuropeptides are found in both mammals and invertebrates and can modulate neural function through activation of G-protein-coupled receptors (GPCRS). The precise mechanisms by which many of these GPCRs modulate specific signaling cascades to regulate neural function are not well defined. We used Drosophila melanogaster as a model to examine both the cellular and behavioral effects of DPKQDFMRFamide, the most abundant peptide encoded by the dFMRF gene. We show that DPKQDFMRFamide enhanced synaptic transmission through activation of two G-protein-coupled receptors, Fmrf Receptor (FR) and Dromyosupressin Receptor-2 (DmsR-2). The peptide increased both the presynaptic Ca(2+) response and the quantal content of released transmitter. Peptide-induced modulation of synaptic function could be abrogated by depleting intracellular Ca(2+) stores or by interfering with Ca(2+) release from the endoplasmic reticulum through disruption of either the ryanodine receptor or the inositol 1,4,5-trisphosphate receptor. The peptide also altered behavior. Exogenous DPKQDFMRFamide enhanced fictive locomotion; this required both the FR and DmsR-2. Likewise, both receptors were required for an escape response to intense light exposure. Thus, coincident detection of a peptide by two GPCRs modulates synaptic function through effects of Ca(2+)-induced Ca(2+) release, and we hypothesize that these mechanisms are involved in behavioral responses to environmental stress.


Asunto(s)
Proteínas de Drosophila/fisiología , Drosophila melanogaster/fisiología , Reacción de Fuga/fisiología , FMRFamida/fisiología , Hormonas de Insectos/metabolismo , Neuropéptidos/metabolismo , Precursores de Proteínas/fisiología , Receptores Acoplados a Proteínas G/fisiología , Receptores de Péptidos/fisiología , Transmisión Sináptica/fisiología , Animales , Conducta Animal/fisiología , Señalización del Calcio/fisiología , Proteínas de Drosophila/agonistas , Femenino , Hormonas de Insectos/fisiología , Masculino , Actividad Motora/fisiología , Neuropéptidos/fisiología , Neurotransmisores/metabolismo , Neurotransmisores/fisiología , Receptores Acoplados a Proteínas G/agonistas , Receptores de Péptidos de Invertebrados/agonistas , Receptores de Péptidos de Invertebrados/fisiología , Receptores de Péptidos/agonistas , Estrés Fisiológico/fisiología
18.
Encephale ; 36 Suppl 2: D73-82, 2010 Jun.
Artículo en Francés | MEDLINE | ID: mdl-20513464

RESUMEN

CONTEXT AND AIM: Depression is a quite common condition, and its treatment is mainly provided by General Practitioner (GP). It is already known that detection and treatment requires significant improvement. The well known and high consumption of antidepressant drugs in France, the highest of all other European countries, requires specific studies. The causes of this situation are not clear and seem to be numerous: Patient's demands, social claims; lack of initial and continuous medical education, bad GP demographic trends, and lack of them in rural areas; pharmaceutical company pressure; and organisation of the health care system. GP are the main medical actors of the primary care system in France. The aim of this study was to survey GP perceptions on secondary care services, seek the views and barriers to the provision of good services, and ask them about perceptions and solutions they could suggest. METHODS: A structured postal questionnaire was sent to all GP of the north-west region of France, asking physicians about obstacles perceived when taking care of depressive patients; factors influencing the use of services, specialised advice, treatments, access to psychiatrists and psychological care. Their psychiatric knowledge and demographic data were also assessed. Quantitative data were analysed using Epi-Info software, and qualitative data were transcribed and coded manually. RESULTS: A total of 25% of the GP returned the questionnaire (n=2097 in 8709). The sample profile was the same as the studied population. Less than a third of the GP (28%) were aware of the clinical guidelines on depression, and less than a fifth (18%) had clinical experience of psychiatry during their studies. Lack of time was not the main obstacle assessed by the GP. Their complaints were about lack of mental health services, difficulty in accessing services, and about general liaison between primary and secondary health care services: they reported difficulties obtaining quick and good response from the specialist either for emergency or non emergency cases. Regarding secondary care, they mainly referred to the psychiatrist, rather than to the psychologist, probably because this second option is not reimbursed by the social security system. Not surprisingly, medication was cited as the most frequently used treatment, followed by psychotherapy and cognitive behavioral therapy (CBT), and almost never self help literature and self help groups. Trained GP considered they were much more comfortable coping with depressed patients, less frequently using secondary care providers, and easily alternative solutions rather than antidepressant drugs. This situation suggests the usefulness of medical education, and is attested by many qualitative answers. DISCUSSION: It is not sure that the low rate of knowledge of the guidelines should be judged only as a lack of professionalism. According to the "French Society of Primary Care", clinical guidelines need updating, and it is known that those available could be useful only for half of the situations encountered in primary care. Operational propositions urgently need to be proposed. Recent questioning of the real interest of pharmaceutical options in the treatment of depression is another argument. Nor can we wait for a hypothetic rise in the demographic situation. The GP have several propositions to improve these problems, e.g. continuous medical education (CME) focusing on "patient centred therapy", dedicated hotline or circuit for depressed people, and an adapted sociomedical directory. They also feel that political awareness about lack of physicians is required, but say that improving quality of care does not rely only on improving demographics. They ask for funds for psychological care. When thinking about the circuit of care, the role of all care providers, and their communication, a global vision appears unavoidable, which would get rid of the divisions between out-patients and the hospital. CONCLUSION: Despite an unavoidable questioning on the dysfunctions of the health care system, quality of care and probably pharmaceutical consumption for the depressed patient might be improved by simple tools, such as adapted CME for primary care physicians, and communication improvement between secondary and primary care systems.


Asunto(s)
Trastorno Depresivo Mayor/diagnóstico , Trastorno Depresivo Mayor/terapia , Medicina General , Atención Primaria de Salud , Actitud del Personal de Salud , Conducta Cooperativa , Curriculum , Recolección de Datos , Trastorno Depresivo Mayor/psicología , Educación Médica Continua , Femenino , Francia , Medicina General/educación , Adhesión a Directriz , Investigación sobre Servicios de Salud , Humanos , Comunicación Interdisciplinaria , Masculino , Persona de Mediana Edad , Evaluación de Procesos y Resultados en Atención de Salud , Pautas de la Práctica en Medicina , Derivación y Consulta , Encuestas y Cuestionarios
19.
Cardiology ; 112(2): 129-34, 2009.
Artículo en Inglés | MEDLINE | ID: mdl-18596374

RESUMEN

OBJECTIVES: Whereas administration of erythropoietin (EPO) acutely after myocardial infarction (MI) reduces infarct size and chronic EPO therapy attenuates post-MI remodeling, the safety of chronic EPO therapy following MI is unknown. Therefore, we examined the thrombogenic effects of a chronic EPO therapy after MI. METHODS: Rats underwent coronary occlusion followed by reperfusion. They were assigned to one of the following groups: EPO-A, single injection of EPO 5,000 U/kg at the time of reperfusion; EPO-C, injection of EPO 5,000 U/kg at the time of reperfusion followed by 300 U/kg/week; PBS-C, injection of vehicle only. After eight weeks of treatment they were exposed to a validated prethrombotic test based on partial stenosis of the inferior vena cava. RESULTS: As compared to the rats receiving vehicle only, the rats treated with EPO exhibited a significant reduction in MI size (28.7 +/- 2.1% and 25.8 +/- 1.9 vs. 39.8 +/- 3.0% in EPO-A, EPO-C and PBS-C, respectively; p < 0.05). Whereas the hematocrit was significantly increased in EPO-C (59.7 +/- 2.0% vs. 44.7 +/- 0.9% in EPO-A, p < 0.001), the proportion of rats in which a thrombus occurred was similar in all groups (p = 0.52). CONCLUSION: Chronic EPO therapy added to the single high dose of EPO injected acutely did not induce venous pro-thrombotic effect in rats.


Asunto(s)
Eritropoyetina/farmacología , Infarto del Miocardio/tratamiento farmacológico , Trombosis de la Vena/prevención & control , Remodelación Ventricular/efectos de los fármacos , Animales , Modelos Animales de Enfermedad , Hematócrito , Masculino , Infarto del Miocardio/patología , Miocardio/patología , Ratas , Ratas Sprague-Dawley
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA