Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 14 de 14
Filtrar
1.
Philos Trans R Soc Lond B Biol Sci ; 372(1721)2017 May 26.
Artículo en Inglés | MEDLINE | ID: mdl-28396476

RESUMEN

The recent Ebola epidemic in West Africa highlights how engaging with the sociocultural dimensions of epidemics is critical to mounting an effective outbreak response. Community engagement was pivotal to ending the epidemic and will be to post-Ebola recovery, health system strengthening and future epidemic preparedness and response. Extensive literatures in the social sciences have emphasized how simple notions of community, which project solidarity onto complex hierarchies and politics, can lead to ineffective policies and unintended consequences at the local level, including doing harm to vulnerable populations. This article reflects on the nature of community engagement during the Ebola epidemic and demonstrates a disjuncture between local realities and what is being imagined in post-Ebola reports about the lessons that need to be learned for the future. We argue that to achieve stated aims of building trust and strengthening outbreak response and health systems, public health institutions need to reorientate their conceptualization of 'the community' and develop ways of working which take complex social and political relationships into account.This article is part of the themed issue 'The 2013-2016 West African Ebola epidemic: data, decision-making and disease control'.


Asunto(s)
Participación de la Comunidad/psicología , Fiebre Hemorrágica Ebola/psicología , Salud Pública/métodos , África Occidental , Humanos , Política
2.
Naturwissenschaften ; 101(4): 313-22, 2014 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-24563098

RESUMEN

The mode of life of the early Tertiary giant bird Gastornis has long been a matter of controversy. Although it has often been reconstructed as an apex predator feeding on small mammals, according to other interpretations, it was in fact a large herbivore. To determine the diet of this bird, we analyze here the carbon isotope composition of the bone apatite from Gastornis and contemporaneous herbivorous mammals. Based on (13)C-enrichment measured between carbonate and diet of carnivorous and herbivorous modern birds, the carbonate δ(13)C values of Gastornis bone remains, recovered from four Paleocene and Eocene French localities, indicate that this bird fed on plants. This is confirmed by a morphofunctional study showing that the reconstructed jaw musculature of Gastornis was similar to that of living herbivorous birds and unlike that of carnivorous forms. The herbivorous Gastornis was the largest terrestrial tetrapod in the Paleocene biota of Europe, unlike the situation in North America and Asia, where Gastornis is first recorded in the early Eocene, and the largest Paleocene animals were herbivorous mammals. The structure of the Paleocene terrestrial ecosystems of Europe may have been similar to that of some large islands, notably Madagascar, prior to the arrival of humans.


Asunto(s)
Aves/fisiología , Dieta , Ecosistema , Fósiles , Herbivoria , Animales , Huesos/química , Radioisótopos de Carbono/análisis
3.
J Public Health (Oxf) ; 36(3): 435-42, 2014 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-23933915

RESUMEN

BACKGROUND: The power to influence many social determinants of health lies within local government sectors that are outside public health's traditional remit. We analyse the challenges of achieving health gains through local government alcohol control policies, where legal and professional practice frameworks appear to conflict with public health action. METHODS: Current legislation governing local alcohol control in England and Wales is reviewed and analysed for barriers and opportunities to implement effective population-level health interventions. Case studies of local government alcohol control practices are described. RESULTS: Addressing alcohol-related health harms is constrained by the absence of a specific legal health licensing objective and differences between public health and legal assessments of the relevance of health evidence to a specific place. Local governments can, however, implement health-relevant policies by developing local evidence for alcohol-related health harms; addressing cumulative impact in licensing policy statements and through other non-legislative approaches such as health and non-health sector partnerships. Innovative local initiatives-for example, minimum unit pricing licensing conditions-can serve as test cases for wider national implementation. CONCLUSIONS: By combining the powers available to the many local government sectors involved in alcohol control, alcohol-related health and social harms can be tackled through existing local mechanisms.


Asunto(s)
Consumo de Bebidas Alcohólicas/prevención & control , Gobierno Local , Política Pública , Consumo de Bebidas Alcohólicas/efectos adversos , Consumo de Bebidas Alcohólicas/legislación & jurisprudencia , Bebidas Alcohólicas/efectos adversos , Inglaterra , Humanos , Administración en Salud Pública/legislación & jurisprudencia , Administración en Salud Pública/métodos , Política Pública/legislación & jurisprudencia , Gales
4.
Phys Chem Chem Phys ; 10(41): 6233-7, 2008 Nov 07.
Artículo en Inglés | MEDLINE | ID: mdl-18936846

RESUMEN

In this paper we report for the first time on the room temperature template synthesis of germanium and silicon nanowires by potentiostatic electrochemical deposition from the air- and water stable ionic liquid 1-butyl-1-methylpyrrolidinium bis(trifluoromethylsulfonyl)amide ([Py(1,4)]Tf(2)N) containing GeCl(4) and SiCl(4) as a Ge and Si source, respectively. Commercially-available track-etched polycarbonate membranes (PC) with an average nominal pore diameter of 90-400 nm were used as templates. Ge and Si nanowires with an average diameter corresponding to the nanopores' diameter and lengths of a few micrometres were reproducibly obtained. Structural characterization of the nanowires was performed by EDX, TEM, HR-SEM and Raman spectroscopy. Despite the rough surface of the nanowires, governed mostly by the original shape of the nanopore's wall of the commercially-available PC membrane, preliminary structural characterizations demonstrate the promising prospective of this innovative elaboration process compared to constraining high vacuum and high temperature methods.


Asunto(s)
Galvanoplastia/métodos , Germanio/química , Líquidos Iónicos/química , Compuestos de Silicona/química , Electrónica/métodos , Microscopía Electrónica de Rastreo , Nanotecnología/métodos , Nanocables , Cemento de Policarboxilato , Espectrometría Raman , Estrés Mecánico
5.
Nano Lett ; 8(10): 3468-74, 2008 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-18788792

RESUMEN

Silicon nanowires were fabricated for the first time by electrochemical template synthesis at room temperature. This innovative, cheap, and simple process consists of electroreduction of Si ions using a nonaqueous solvent and insulating nanoporous membranes with average pore diameters from 400 to 15 nm which fix the nanowires diameters. Characterization techniques such as scanning and transmission electron microscopies, infrared absorption measurements, X-ray diffraction experiments, energy dispersive X-ray, and Raman spectrometries show that the as-deposited silicon nanowires are amorphous, composed of pure Si and homogeneous in sizes with average diameters and lengths well matching with the nanopores' diameters and the thicknesses of the membranes. Thanks to annealing treatments, it is possible to crystallize the Si nanowires, demonstrating the potentiality for this innovative electrochemical process to obtain a wide range of Si nanowires with well controlled diameters and lengths.


Asunto(s)
Electroquímica/métodos , Líquidos Iónicos/química , Iones , Nanopartículas/química , Nanotecnología/métodos , Galvanoplastia , Diseño de Equipo , Microscopía Electrónica de Rastreo , Microscopía Electrónica de Transmisión , Silicio/química , Espectrofotometría Infrarroja/métodos , Difracción de Rayos X , Rayos X
6.
J Clin Microbiol ; 39(7): 2541-7, 2001 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-11427566

RESUMEN

We have developed a PCR-based assay which allows the detection of staphylococci at the genus level by targeting the tuf gene, which encodes the elongation factor Tu. Degenerate PCR primers derived from consensus regions of several tuf genes were used to amplify a target region of 884 bp from 11 representative staphylococcal species. Subsequently, the entire nucleotide sequence of these amplicons was determined. The analysis of a multiple alignment of these sequences revealed regions conserved among staphylococci but distinct from those of other gram-positive bacteria genetically related to staphylococci. PCR primers complementary to these regions could amplify specifically and efficiently a DNA fragment of 370 bp for all of 27 different staphylococcal species tested. There was no amplification with genomic DNA prepared from 53 nonstaphylococcal species tested to verify the specificity of the assay (20 gram positive and 33 gram negative). Furthermore, this assay amplified efficiently all 27 American Type Culture Collection (ATCC) staphylococcal reference strains as well as 307 clinical isolates of staphylococci from the Québec City region. Analysis of the multiple sequence alignment for the 884-bp fragment for the 11 staphylococcal species as well as comparison of the sequences for the 370-bp amplicon from five unrelated ATCC and clinical strains for each of the species S. aureus, S. epidermidis, S. haemolyticus, S. hominis, and S. saprophyticus demonstrated sufficient interspecies polymorphism to generate genus- and species-specific capture probes. This sequence information allowed the development of Staphylococcus-specific and species-specific (targeting S. aureus, S. epidermidis, S. haemolyticus, S. hominis, or S. saprophyticus) capture probes hybridizing to the 370-bp amplicon. In conclusion, this PCR assay is suitable for detection of staphylococci at both genus and species levels.


Asunto(s)
Factor Tu de Elongación Peptídica/genética , Reacción en Cadena de la Polimerasa/métodos , Staphylococcus/clasificación , Cartilla de ADN , ADN Bacteriano/análisis , ADN Bacteriano/genética , Genes Bacterianos , Humanos , Datos de Secuencia Molecular , Filogenia , Sensibilidad y Especificidad , Análisis de Secuencia de ADN , Especificidad de la Especie , Infecciones Estafilocócicas/microbiología , Staphylococcus/genética , Staphylococcus/aislamiento & purificación
7.
J Antimicrob Chemother ; 46(4): 527-34, 2000 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-11020248

RESUMEN

Multiresistant staphylococci (82 Staphylococcus aureus and 114 coagulase-negative staphylococci) were characterized by testing with rapid multiplex polymerase chain reaction (PCR) assays for species identification and detection of associated antibiotic resistance genes. These 196 staphylococci were isolated from 149 adult patients who developed wound infection after elective coronary artery bypass grafts and/or valve surgery. The multiplex PCR assays allowed identification of the most common staphylococcal species with S. aureus- and Staphylococcus epidermidis-specific primers as well as the detection of the erythromycin resistance genes ermA, ermB, ermC and msrA, the aminoglycoside resistance gene aac(6')-aph(2"), the oxacillin resistance gene mecA and the penicillin resistance gene blaZ. There was a very good correlation between the genotypic analysis by PCR and the phenotype determined by standard methods of susceptibility testing and identification of staphylococcal species: 100% for erythromycin resistance, 98.0% for gentamicin resistance, 99.0% for oxacillin resistance, 100% for penicillin resistance and 100% for S. aureus and S. epidermidis species identification. This study suggests that the incidence and distribution of the tested clinically relevant antibiotic resistance genes in staphylococci associated with infections after cardiac surgery do not differ from those in strains from other infections. These multiplex PCR assays may be used as diagnostic tools to replace or complement standard methods of susceptibility testing and identification of staphylococci.


Asunto(s)
Puente de Arteria Coronaria/efectos adversos , Resistencia a Múltiples Medicamentos/genética , Reacción en Cadena de la Polimerasa/métodos , Infecciones Estafilocócicas/genética , Staphylococcus aureus/genética , Staphylococcus epidermidis/genética , Infección de la Herida Quirúrgica/genética , Adulto , Humanos , Pruebas de Sensibilidad Microbiana , Staphylococcus aureus/efectos de los fármacos , Staphylococcus epidermidis/efectos de los fármacos
8.
J Clin Microbiol ; 38(9): 3280-4, 2000 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-10970371

RESUMEN

Staphylococcus saprophyticus is one of the most frequently encountered microorganisms associated with acute urinary tract infections (UTIs) in young, sexually active female outpatients. Conventional identification methods based on biochemical characteristics can efficiently identify S. saprophyticus, but the rapidities of these methods need to be improved. Rapid and direct identification of this bacterium from urine samples would be useful to improve time required for the diagnosis of S. saprophyticus infections in the clinical microbiology laboratory. We have developed a PCR-based assay for the specific detection of S. saprophyticus. An arbitrarily primed PCR amplification product of 380 bp specific for S. saprophyticus was sequenced and used to design a set of S. saprophyticus-specific PCR amplification primers. The PCR assay was specific for S. saprophyticus when tested with DNA from 49 gram-positive and 31 gram-negative bacterial species. This assay was also able to amplify efficiently DNA from all 60 strains of S. saprophyticus from various origins tested. This assay was adapted for direct detection from urine samples. The sensitivity levels achieved with urine samples was 19 CFU with 30 cycles of amplification and 0.5 CFU with 40 cycles of amplification. This PCR assay for the specific detection of S. saprophyticus is simple and rapid (approximately 90 min, including the time for urine specimen preparation).


Asunto(s)
Reacción en Cadena de la Polimerasa/métodos , Infecciones Estafilocócicas/diagnóstico , Staphylococcus/aislamiento & purificación , Infecciones Urinarias/diagnóstico , Orina/microbiología , ADN Bacteriano/análisis , Femenino , Humanos , Datos de Secuencia Molecular , Sensibilidad y Especificidad , Infecciones Estafilocócicas/microbiología , Staphylococcus/clasificación , Staphylococcus/genética , Factores de Tiempo , Infecciones Urinarias/microbiología
9.
Behav Brain Res ; 108(2): 169-80, 2000 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-10701660

RESUMEN

In a placebo-controlled, double-blind study, we measured the effects of low dose lorazepam on attentional and motor factors involved in saccadic and smooth pursuit eye movements. We manipulated the temporal interval between the extinction of the central fixation target and the appearance of a second eccentric target (gap/overlap step paradigm). The second target was either stationary (saccade trial) or moving in a direction opposite to the step (pursuit trial). Gap/overlap effects on the latency of saccadic and smooth pursuit eye movements were measured before and after oral intake of either lorazepam or placebo. Pharmacological effects on the dynamics and the accuracy of both types of eye movements were also investigated. In 14 healthy volunteers, we found that the temporal interval between fixation target offset and eccentric target onset modulates the latency of saccadic and smooth pursuit eye movements in a similar way. As compared to placebo, lorazepam significantly increased the latency of both types of eye movements, but did not modify the gap/overlap effect. Moreover, lorazepam significantly decreased the peak velocity of the first saccade towards the eccentric stationary target, as well as the gain of tracking towards the eccentric moving target. However, the overall accuracy of both behaviors was not significantly affected, indicating that systematic errors in foveating or tracking were detected and corrected by appropriate corrective or catch-up saccades, respectively. Results are discussed in terms of shared/different mechanisms for saccadic and pursuit systems in primates.


Asunto(s)
Moduladores del GABA/farmacología , Hipnóticos y Sedantes/farmacología , Lorazepam/farmacología , Seguimiento Ocular Uniforme/efectos de los fármacos , Movimientos Sacádicos/efectos de los fármacos , Adulto , Análisis de Varianza , Estudios Cruzados , Método Doble Ciego , Femenino , Humanos , Masculino , Seguimiento Ocular Uniforme/fisiología , Tiempo de Reacción , Movimientos Sacádicos/fisiología
10.
Antimicrob Agents Chemother ; 44(2): 231-8, 2000 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-10639342

RESUMEN

Clinical isolates of Staphylococcus aureus (a total of 206) and S. epidermidis (a total of 188) from various countries were tested with multiplex PCR assays to detect clinically relevant antibiotic resistance genes associated with staphylococci. The targeted genes are implicated in resistance to oxacillin (mecA), gentamicin ¿aac(6')-aph(2"), and erythromycin (ermA, ermB, ermC, and msrA). We found a nearly perfect correlation between genotypic and phenotypic analysis for most of these 394 strains, showing the following correlations: 98% for oxacillin resistance, 100% for gentamicin resistance, and 98.5% for erythromycin resistance. The discrepant results were (i) eight strains found to be positive by PCR for mecA or ermC but susceptible to the corresponding antibiotic based on disk diffusion and (ii) six strains of S. aureus found to be negative by PCR for mecA or for the four erythromycin resistance genes targeted but resistant to the corresponding antibiotic. In order to demonstrate in vitro that the eight susceptible strains harboring the resistance gene may become resistant, we subcultured the susceptible strains on media with increasing gradients of the antibiotic. We were able to select cells demonstrating a resistant phenotype for all of these eight strains carrying the resistance gene based on disk diffusion and MIC determinations. The four oxacillin-resistant strains negative for mecA were PCR positive for blaZ and had the phenotype of beta-lactamase hyperproducers, which could explain their borderline oxacillin resistance phenotype. The erythromycin resistance for the two strains found to be negative by PCR is probably associated with a novel mechanism. This study reiterates the usefulness of DNA-based assays for the detection of antibiotic resistance genes associated with staphylococcal infections.


Asunto(s)
Farmacorresistencia Microbiana/genética , Genes Bacterianos/genética , Reacción en Cadena de la Polimerasa/métodos , Staphylococcus aureus/efectos de los fármacos , Staphylococcus epidermidis/efectos de los fármacos , Antibacterianos/farmacología , Genotipo , Humanos , Pruebas de Sensibilidad Microbiana , Staphylococcus aureus/genética , Staphylococcus epidermidis/genética
11.
J Clin Microbiol ; 37(11): 3497-503, 1999 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-10523541

RESUMEN

Enterococci are becoming major nosocomial pathogens, and increasing resistance to vancomycin has been well documented. Conventional identification methods, which are based on culturing, require 2 to 3 days to provide results. PCR has provided a means for the culture-independent detection of enterococci in a variety of clinical specimens and is capable of yielding results in just a few hours. However, all PCR-based assays developed so far are species specific only for clinically important enterococci. We have developed a PCR-based assay which allows the detection of enterococci at the genus level by targeting the tuf gene, which encodes elongation factor EF-Tu. Initially, we compared the nucleotide sequences of the tuf gene from several bacterial species (available in public databases) and designed degenerate PCR primers derived from conserved regions. These primers were used to amplify a target region of 803 bp from four enterococcal species (Enterococcus avium, E. faecalis, E. faecium, and E. gallinarum). Subsequently, the complete nucleotide sequences of these amplicons were determined. The analysis of a multiple alignment of these sequences revealed regions conserved among enterococci but distinct from those of other bacteria. PCR primers complementary to these regions allowed amplification of genomic DNAs from 14 of 15 species of enterococci tested (E. solitarius DNA could not be amplified). There was no amplification with a majority of 79 nonenterococcal bacterial species, except for 2 Abiotrophia species and several Listeria species. Furthermore, this assay efficiently amplified all 159 clinical isolates of enterococci tested (61 E. faecium, 77 E. faecalis, 9 E. gallinarum, and 12 E. casseliflavus isolates). Interestingly, the preliminary sequence comparison of the amplicons for four enterococcal species demonstrated that there were some sequence variations which may be used to generate species-specific internal probes. In conclusion, this rapid PCR-based assay is capable of detecting all clinically important enterococci and has potential for use in clinical microbiology laboratories.


Asunto(s)
Enterococcus/genética , Reacción en Cadena de la Polimerasa/métodos , Técnicas de Tipificación Bacteriana , Secuencia de Bases , Infección Hospitalaria/tratamiento farmacológico , Cartilla de ADN/genética , Enterococcus/clasificación , Enterococcus/aislamiento & purificación , Enterococcus faecalis/clasificación , Enterococcus faecalis/genética , Enterococcus faecalis/aislamiento & purificación , Enterococcus faecium/clasificación , Enterococcus faecium/genética , Enterococcus faecium/aislamiento & purificación , Genes Bacterianos , Infecciones por Bacterias Grampositivas/diagnóstico , Humanos , Datos de Secuencia Molecular , Factor Tu de Elongación Peptídica/genética , Especificidad de la Especie , Virulencia
12.
J Clin Microbiol ; 36(3): 618-23, 1998 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-9508283

RESUMEN

Staphylococcus aureus is the cause of serious infections in humans, including endocarditis, deep-seated abscesses, and bacteremia, which lead to toxic and septic shock syndromes. Rapid and direct identification of this bacterium specifically and ubiquitously directly from clinical specimens would be useful in improving the diagnosis of S. aureus infections in the clinical microbiology laboratory. A wide variety of kits based on biochemical characteristics efficiently identify S. aureus, but the rapidity and the accuracy of each of these methods combined with testing of clinically relevant antibiotic resistance genes need to be improved. On the basis of hybridization assays with randomly selected clones from an S. aureus genomic library, we have identified a chromosomal DNA fragment which is specific for S. aureus and which detected all 82 S. aureus isolates tested. This 442-bp fragment was sequenced and was used to design a set of PCR amplification primers. The PCR assay was also specific and ubiquitous for the identification from bacterial cultures of 195 clinical strains of S. aureus isolated from a variety of anatomical sites and obtained from hospitals throughout the world. The PCR assay that we have developed is simple and can be performed in about 1 h. This DNA-based test provides a novel diagnostic tool for the diagnosis of S. aureus infections.


Asunto(s)
Reacción en Cadena de la Polimerasa/métodos , Infecciones Estafilocócicas/diagnóstico , Staphylococcus aureus/aislamiento & purificación , Clonación Molecular , Cartilla de ADN , Sondas de ADN , Estudios de Evaluación como Asunto , Genoma Bacteriano , Humanos , Sensibilidad y Especificidad , Especificidad de la Especie , Staphylococcus aureus/clasificación , Staphylococcus aureus/genética
13.
J Clin Microbiol ; 34(12): 2888-93, 1996 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-8940417

RESUMEN

Staphylococcus epidermidis is an aerobic gram-positive coccus that is now recognized among the coagulase-negative staphylococci as an etiological agent with an important range of pathogenicity in humans. Several diagnostic kits based on biochemical or immunological reactions can efficiently identify Staphylococcus aureus. However, these tests are often unreliable for the identification of coagulase-negative staphylococcal species including S. epidermidis. Since DNA-based assays for the species-specific identification of S. epidermidis remain unavailable, we have developed such tests in order to improve the accuracy and the rapidity of tests for the diagnosis of S. epidermidis infections. On the basis of the results of hybridization assays with clones randomly selected from an S. epidermidis genomic library, we identified a chromosomal DNA fragment which is specific and 100% ubiquitous for the identification of S. epidermidis. This 705-bp fragment was sequenced and used to design PCR amplification primers. PCR assays with the selected primers were also highly specific and ubiquitous for the identification from bacterial cultures of clinical isolates of S. epidermidis from a variety of anatomic sites. While three strains of S. capitis were misidentified as S. epidermidis with the API Staph-Ident system and 2.5% of the S. epidermidis identifications were inconclusive with the MicroScan Autoscan-4 system, the PCR assay was highly specific and allowed for the correct identification of all 79 S. epidermidis strains tested. The PCR assays developed are simple and can be performed in about 1 h. The DNA-based tests provide novel diagnostic tools for improving the diagnosis of S. epidermidis infections.


Asunto(s)
Técnicas Bacteriológicas , ADN Bacteriano/genética , Reacción en Cadena de la Polimerasa/métodos , Infecciones Estafilocócicas/diagnóstico , Staphylococcus epidermidis/genética , Staphylococcus epidermidis/aislamiento & purificación , Secuencia de Bases , Clonación Molecular , Cartilla de ADN/genética , Sondas de ADN , Errores Diagnósticos , Estudios de Evaluación como Asunto , Humanos , Especificidad de la Especie , Infecciones Estafilocócicas/microbiología , Staphylococcus/clasificación , Staphylococcus/genética , Staphylococcus/aislamiento & purificación
14.
Mil Med ; 132(10): 834-7, 1967 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-4965478
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA