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1.
Infect Dis Now ; 53(4): 104694, 2023 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-36948248

RESUMEN

In 2020 the French Society of Rhumatology (SFR) published an update of the 1990 recommendations for management of bacterial arthritis in adults. While we (French ID Society, SPILF) totally endorse this update, we wished to provide further information about specific antibiotic treatments. The present update focuses on antibiotics with good distribution in bone and joint. It is important to monitor their dosage, which should be maximized according to PK/PD parameters. Dosages proposed in this update are high, with the optimized mode of administration for intravenous betalactams (continuous or intermittent infusion). We give tools for the best dosage adaptation to conditions such as obesity or renal insufficiency. In case of enterobacter infection, with an antibiogram result "susceptible for high dosage", we recommend the requesting of specialized advice from an ID physician. More often than not, it is possible to prescribe antibiotics via the oral route as soon as blood cultures are sterile and clinical have symptoms shown improvement. Duration of antibiotic treatment is 6 weeks for Staphylococcus aureus, and 4 weeks for the other bacteria (except for Neisseria: 7 days).


Asunto(s)
Artritis Infecciosa , Infecciones Estafilocócicas , Humanos , Adulto , Niño , Antibacterianos/uso terapéutico , Infecciones Estafilocócicas/tratamiento farmacológico , Artritis Infecciosa/diagnóstico , Artritis Infecciosa/tratamiento farmacológico , Administración Oral , Administración Intravenosa
2.
Int J Pediatr Otorhinolaryngol ; 121: 137-142, 2019 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-30903929

RESUMEN

OBJECTIVES: Kawasaki disease (KD) is a febrile multisystemic vasculitis of unknown etiology whose coronary prognosis is improved by early diagnosis and management. The objective of this study was to describe ENT manifestations encountered and to look for a delayed diagnosis associated with these manifestations. METHODS: A retrospective descriptive single-center study was conducted in Lyon between January 2009 and December 2017. All children treated for Kawasaki disease were included in the study. Clinical, biological and cardiac ultrasound data were collected. According to the diagnosis made at the first medical visit, children were classified into two groups: diagnosis of ENT spectrum or non-ENT diagnosis. The diagnostic times were compared by a Student test. RESULTS: 142 patients were included: 64 in the ENT diagnostic group, 78 in the non-ENT diagnostic group. When the initial diagnosis was of ENT spectrum, the diagnostic time of KD was significantly longer: 8.51 days vs 5.77 days - (p < 0.01). The total duration of fever was also longer - 10.92 vs 8.32 days - (p = 0.013) - and the frequency of antibiotics intake more important - 92.2% vs 46.2% - (p < 0.01). Four children underwent surgery in the ENT diagnostic group: two retro-pharyngeal abscesses, one paracentesis and one cervicectomy. CONCLUSIONS: ENT manifestations are frequently at the forefront of KD and constitute a misleading clinical picture responsible for delayed diagnosis and potentially inappropriate medico-surgical management. It is necessary to provide more education to practitioners for earlier recognition of Kawasaki disease.


Asunto(s)
Síndrome Mucocutáneo Linfonodular/complicaciones , Síndrome Mucocutáneo Linfonodular/diagnóstico , Enfermedades Otorrinolaringológicas/diagnóstico , Enfermedades Otorrinolaringológicas/etiología , Antibacterianos/uso terapéutico , Niño , Preescolar , Diagnóstico Tardío , Diagnóstico Diferencial , Femenino , Fiebre/etiología , Humanos , Lactante , Masculino , Síndrome Mucocutáneo Linfonodular/terapia , Enfermedades Otorrinolaringológicas/terapia , Estudios Retrospectivos , Procedimientos Innecesarios
3.
BMC Infect Dis ; 18(1): 537, 2018 Oct 29.
Artículo en Inglés | MEDLINE | ID: mdl-30373528

RESUMEN

BACKGROUND: In recent years, metagenomic Next-Generation Sequencing (mNGS) has increasingly been used for an accurate assumption-free virological diagnosis. However, the systematic workflow evaluation on clinical respiratory samples and implementation of quality controls (QCs) is still lacking. METHODS: A total of 3 QCs were implemented and processed through the whole mNGS workflow: a no-template-control to evaluate contamination issues during the process; an internal and an external QC to check the integrity of the reagents, equipment, the presence of inhibitors, and to allow the validation of results for each sample. The workflow was then evaluated on 37 clinical respiratory samples from patients with acute respiratory infections previously tested for a broad panel of viruses using semi-quantitative real-time PCR assays (28 positive samples including 6 multiple viral infections; 9 negative samples). Selected specimens included nasopharyngeal swabs (n = 20), aspirates (n = 10), or sputums (n = 7). RESULTS: The optimal spiking level of the internal QC was first determined in order to be sufficiently detected without overconsumption of sequencing reads. According to QC validation criteria, mNGS results were validated for 34/37 selected samples. For valid samples, viral genotypes were accurately determined for 36/36 viruses detected with PCR (viral genome coverage ranged from 0.6 to 100%, median = 67.7%). This mNGS workflow allowed the detection of DNA and RNA viruses up to a semi-quantitative PCR Ct value of 36. The six multiple viral infections involving 2 to 4 viruses were also fully characterized. A strong correlation between results of mNGS and real-time PCR was obtained for each type of viral genome (R2 ranged from 0.72 for linear single-stranded (ss) RNA viruses to 0.98 for linear ssDNA viruses). CONCLUSIONS: Although the potential of mNGS technology is very promising, further evaluation studies are urgently needed for its routine clinical use within a reasonable timeframe. The approach described herein is crucial to bring standardization and to ensure the quality of the generated sequences in clinical setting. We provide an easy-to-use single protocol successfully evaluated for the characterization of a broad and representative panel of DNA and RNA respiratory viruses in various types of clinical samples.


Asunto(s)
Virus ADN/genética , Secuenciación de Nucleótidos de Alto Rendimiento/normas , Metagenómica/normas , Virus ARN/genética , Infecciones del Sistema Respiratorio/virología , Virus ADN/aislamiento & purificación , ADN Viral/química , ADN Viral/aislamiento & purificación , ADN Viral/metabolismo , Humanos , Control de Calidad , Virus ARN/aislamiento & purificación , ARN Viral/química , ARN Viral/aislamiento & purificación , ARN Viral/metabolismo , Reacción en Cadena en Tiempo Real de la Polimerasa , Infecciones del Sistema Respiratorio/diagnóstico
4.
J Dent Res ; 97(10): 1152-1159, 2018 09.
Artículo en Inglés | MEDLINE | ID: mdl-29879365

RESUMEN

Transplantation of bone marrow mesenchymal stem cells (BMDCs) into a denervated side of the spinal cord was reported to be a useful option for axonal regeneration. The innervation of teeth is essential for their function and protection but does not occur spontaneously after injury. Cultured reassociations between dissociated embryonic dental mesenchymal and epithelial cells and implantation lead to a vascularized tooth organ regeneration. However, when reassociations were coimplanted with a trigeminal ganglion (TG), innervation did not occur. On the other hand, reassociations between mixed embryonic dental mesenchymal cells and bone marrow-derived cells isolated from green fluorescent protein (GFP) transgenic mice (BMDCs-GFP) (50/50) with an intact and competent dental epithelium (ED14) were innervated. In the present study, we verified the stemness of isolated BMDCs, confirmed their potential role in the innervation of bioengineered teeth, and analyzed the mechanisms by which this innervation can occur. For that purpose, reassociations between mixed embryonic dental mesenchymal cells and BMDCs-GFP with an intact and competent dental epithelium were cultured and coimplanted subcutaneously with a TG for 2 wk in ICR mice. Axons entered the dental pulp and reached the odontoblast layer. BMDCs-GFP were detected at the base of the tooth, with some being present in the pulp associated with the axons. Thus, while having a very limited contribution in tooth formation, they promoted the innervation of the bioengineered teeth. Using quantitative reverse transcription polymerase chain reaction and immunostainings, BMDCs were shown to promote innervation by 2 mechanisms: 1) via immunomodulation by reducing the number of T lymphocytes (CD3+, CD25+) in the implants and 2) by expressing neurotrophic factors such as NGF, BDNF, and NT3 for axonal growth. This strategy using autologous mesenchymal cells coming from bone marrow could be used to innervate bioengineered teeth without treatment with an immunosuppressor such as cyclosporine A (CsA), thus avoiding multiple side effects.


Asunto(s)
Trasplante de Células Madre Mesenquimatosas/métodos , Ingeniería de Tejidos/métodos , Diente/inervación , Animales , Proteínas Fluorescentes Verdes , Células Madre Mesenquimatosas/fisiología , Ratones , Ratones Endogámicos ICR , Ratones Transgénicos , Odontogénesis , Diente/crecimiento & desarrollo
5.
Oncogene ; 37(5): 578-588, 2018 02 01.
Artículo en Inglés | MEDLINE | ID: mdl-28991231

RESUMEN

Mammary gland morphogenesis results from the coordination of proliferation, cohort migration, apoptosis and stem/progenitor cell dynamics. We showed earlier that the transcription repressor Slug is involved in these functions during mammary tubulogenesis. Slug is expressed by a subpopulation of basal epithelial cells, co-expressed with P-cadherin (Pcad). Slug-knockout mammary glands showed excessive branching, similarly to Pcad-knockout. Here, we found that Slug unexpectedly binds and activates Pcad promoter through E-boxes, inducing Pcad expression. We determined that Pcad can mediate several functions of Slug: Pcad promoted clonal mammosphere growth, basal epithelial differentiation, cell-cell dissociation and cell migration, rescuing Slug depletion. Pcad also promoted cell migration in isolated cells, in association with Src activation, focal adhesion reorganization and cell polarization. Pcad, similarly to Slug, was required for in vitro 3D tubulogenesis. Therefore, Pcad appears to be responsible for epithelial-mesenchymal transition-linked plasticity in mammary epithelial cells. In addition, we found that genes from the Slug/Pcad pathway components were co-expressed and specifically correlated in human breast carcinomas subtypes, carrying pathophysiological significance.


Asunto(s)
Neoplasias de la Mama/genética , Cadherinas/genética , Células Epiteliales/patología , Transición Epitelial-Mesenquimal/genética , Glándulas Mamarias Animales/metabolismo , Factores de Transcripción de la Familia Snail/metabolismo , Animales , Neoplasias de la Mama/mortalidad , Neoplasias de la Mama/patología , Cadherinas/metabolismo , Adhesión Celular/genética , Diferenciación Celular/genética , Línea Celular Tumoral , Movimiento Celular/genética , Proliferación Celular/genética , Conjuntos de Datos como Asunto , Femenino , Humanos , Estimación de Kaplan-Meier , Queratinocitos , Glándulas Mamarias Animales/citología , Ratones , Morfogénesis/genética , Regiones Promotoras Genéticas , ARN Interferente Pequeño/metabolismo , Transducción de Señal/genética , Factores de Transcripción de la Familia Snail/genética , Esferoides Celulares , Células Madre/patología
6.
Arch Pediatr ; 24(3): 254-259, 2017 Mar.
Artículo en Francés | MEDLINE | ID: mdl-28161232

RESUMEN

Hemophagocytic lymphohistiocytosis (HLH) is a rare and severe syndrome usually associated with a cytotoxicity deficiency, which leads to an excess of immune response driven by activated macrophages and cytotoxic T cells. In children, HLH can be genetic, as part of a familial lymphohistiocytosis, or secondary: the most frequent causes are systemic-onset juvenile idiopathic arthritis, hematological malignancies, and severe infections, especially with Ebstein-Barr virus or leishmaniosis. We report on the case of a 3-year-old girl with no past medical history, who presented inaugural Pseudomonas aeruginosa maxillary osteitis, with secondary HLH. The rarity of this osteitis, the characteristics of the pathogen, and the onset of HLH oriented the diagnosis toward primary immunodeficiencies, malignancies, or systemic diseases. Steroids were initiated at 2mg/kg/day and were very effective in improving the systemic symptoms. Antibiotic therapy was continued unchanged. A few days after discontinuation of steroids, while the patient was still under antibiotics, she presented with erythroderma. Skin biopsy revealed eosinophil infiltrate in line with the diagnosis of a drug reaction with eosinophilia and systemic symptoms (DRESS), even though we only observed very transient eosinophilia, up to 0.98G/L, during HLH. Stopping antibiotics normalized the symptoms without using systemic corticosteroids. Patch tests confirmed an allergy to piperacillin. These atypical manifestations of DRESS underline that causative diagnosis of HLH is challenging, and DRESS syndrome should be considered.


Asunto(s)
Síndrome de Hipersensibilidad a Medicamentos/diagnóstico , Linfohistiocitosis Hemofagocítica/diagnóstico , Enfermedades Maxilares/diagnóstico , Osteítis/diagnóstico , Piperacilina/efectos adversos , Piperacilina/uso terapéutico , Infecciones por Pseudomonas/diagnóstico , Pseudomonas aeruginosa , Preescolar , Diagnóstico Diferencial , Femenino , Humanos , Linfohistiocitosis Hemofagocítica/tratamiento farmacológico , Enfermedades Maxilares/tratamiento farmacológico , Osteítis/tratamiento farmacológico , Pruebas del Parche , Infecciones por Pseudomonas/tratamiento farmacológico
7.
Acta Biomater ; 50: 493-501, 2017 03 01.
Artículo en Inglés | MEDLINE | ID: mdl-28057509

RESUMEN

The innervation of teeth mediated by axons originating from the trigeminal ganglia is essential for their function and protection. Immunosuppressive therapy using Cyclosporine A (CsA) was found to accelerate the innervation of transplanted tissues and particularly that of bioengineered teeth. To avoid the CsA side effects, we report in this study the preparation of CsA loaded poly(lactic-co-glycolic acid) (PLGA) nanoparticles, their embedding on polycaprolactone (PCL)-based scaffolds and their possible use as templates for the innervation of bioengineered teeth. This PCL scaffold, approved by the FDA and capable of mimicking the extracellular matrix, was obtained by electrospinning and decorated with CsA-loaded PLGA nanoparticles to allow a local sustained action of this immunosuppressive drug. Dental re-associations were co-implanted with a trigeminal ganglion on functionalized scaffolds containing PLGA and PLGA/cyclosporine in adult ICR mice during 2weeks. Histological analyses showed that the designed scaffolds did not alter the teeth development after in vivo implantation. The study of the innervation of the dental re-associations by indirect immunofluorescence and transmission electron microscopy (TEM), showed that 88.4% of the regenerated teeth were innervated when using the CsA-loaded PLGA scaffold. The development of active implants thus allows their potential use in the context of dental engineering. STATEMENT OF SIGNIFICANCE: Tooth innervation is essential for their function and protection and this can be promoted in vivo using polymeric scaffolds functionalized with immunosuppressive drug-loaded nanoparticles. Immunosuppressive therapy using biodegradable nanoparticles loaded with Cyclosporine A was found to accelerate the innervation of bioengineered teeth after two weeks of implantation.


Asunto(s)
Bioingeniería/métodos , Nanoestructuras/química , Andamios del Tejido/química , Diente/inervación , Animales , Ciclosporina/farmacología , Implantes Dentales , Ácido Láctico/síntesis química , Ácido Láctico/química , Ratones Endogámicos ICR , Nanoestructuras/ultraestructura , Poliésteres/química , Ácido Poliglicólico/síntesis química , Ácido Poliglicólico/química , Copolímero de Ácido Poliláctico-Ácido Poliglicólico
8.
Arch Pediatr ; 24(12S): S17-S21, 2017 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-29290229

RESUMEN

Lower respiratory tract infections, i.e., bronchitis, bronchiolitis, and pneumonia, are the second leading cause of antibiotic prescriptions. The vast majority of these infections are due to viruses and are self-limited diseases: most patients recover spontaneously. These two facts explain that antibiotic prescriptions must be limited to some clinical situations for which the diagnosis has to be done early. The first message of this manuscript is to strengthen non-antibiotic prescriptions in many situations such as bronchitis and bronchiolitis. Implementation of pneumococcal conjugate vaccines (PCVs) has reduced the incidence of pneumonia and empyema, and induced a dramatic decrease in the proportion of pneumococcus in these diseases. However, pneumococcus remains probably the leading cause of bacterial pneumonia and empyema and the main target of antibiotic treatment. Furthermore, the implementation of PCVs has reduced resistance to antibiotics including penicillins and macrolides antibiotics, explaining the de-escalation proposed in the last few years, with the reduction of the use if third generation cephalosporins and vancomycin. The therapeutic choices proposed in this article follow the previous official guidelines in France. Serious infections represented by empyema and severe pneumonia remain therapeutic emergencies, most often warranting hospitalization and IV antibiotics.


Asunto(s)
Antibacterianos/uso terapéutico , Infecciones Bacterianas/tratamiento farmacológico , Bronquiolitis/tratamiento farmacológico , Bronquiolitis/microbiología , Bronquitis/tratamiento farmacológico , Bronquitis/microbiología , Neumonía Bacteriana/tratamiento farmacológico , Niño , Humanos , Guías de Práctica Clínica como Asunto
9.
Arch Pediatr ; 24(12S): S22-S25, 2017 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-29290230

RESUMEN

Urinary tract infections are the most frequent documented bacterial infections in children. The antibiotic choices proposed in this manuscript are based on the guidelines published by the Pediatric Infectious Disease Group (GPIP) and the French-Language Infectious Disease Society (SPILF). Dipstick positive for leukocytes and/or nitrites must precede in most circumstances (excluding the newborns, neutropenic patients and those with sepsis), urine culture and antibiotic prescription. The proportion of extended-spectrum ß-lactamase (ESBL) Escherichia coli strains has increased steadily in recent years, and the situations in which oral antibiotic switch is frequently not available are increasing. Cephalosporin resistance remains below 10% in most regions of France. However, there is no doubt that the proportion of resistant strains will increase in the coming years: the only uncertainly concerns the speed of this trend. With the aim of saving penems and promoting outpatient care, this guide proposes among the acceptable initial treatments for febrile urinary tract infections in infants, amikacin. This aminoglycoside remains active against the majority of ESBL strains and can be prescribed in once-daily dose allowing also ambulatory management of patients from pediatric emergency department.


Asunto(s)
Antibacterianos/uso terapéutico , Infecciones Bacterianas/tratamiento farmacológico , Infecciones Urinarias/tratamiento farmacológico , Niño , Humanos
10.
Arch Pediatr ; 24(12S): S30-S35, 2017 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-29290232

RESUMEN

Bacterial skin and soft tissues infections are common in children and frequently do not require systemic antibiotics, especially if lesions are superficial. Careful washing is always indicated in superficial lesions and is often sufficient. Careful evaluation of symptoms (which may be difficult despite the accessibility of the lesions) should be performed before prescription. Therefore, the need for drainage (spontaneous or surgical) should be assessed considering that antibiotics are mostly useless if purulent lesions are drained. Presence of toxinic symptoms (i.e., generalized cutaneous rash, diarrhea, hypotension) are strongly associated with enhanced severity. The bacterial targets for antibiotics are mainly Staphylococcus aureus (SA) and Streptococcus pyogenes. Considering the low incidence of methicillin-resistant SA in France, the French Pediatric Infectious Disease Group recommends the use of amoxicillin + clavulanate as the first-line antibiotic in most children suffering from severe skin infections requiring antibiotic treatment. In patients presenting toxinic symptoms and signs, the adjunction of an antibiotic with antitoxin properties such as clindamycin should be considered.


Asunto(s)
Antibacterianos/uso terapéutico , Infecciones Bacterianas/tratamiento farmacológico , Enfermedades Cutáneas Infecciosas/tratamiento farmacológico , Infecciones de los Tejidos Blandos/tratamiento farmacológico , Niño , Humanos , Guías de Práctica Clínica como Asunto
11.
Arch Pediatr ; 24(12S): S36-S41, 2017 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-29290233

RESUMEN

Acute hematogenous bone and joint infections (osteomyelitis, septic arthritis, osteoarthritis, and spondylodiscitis) affect more frequently children younger than 5 years of age. Early diagnosis and prompt treatment are needed to limit the risk of complications. Children with suspected bone and joint infections (BJI) should be hospitalized at the beginning of treatment. Surgical drainage is indicated in patients with septic arthritis and in those with periosteal abscess. Staphylococcus aureus is involved in BJIs in children at all ages; Kingella kingae is a very common causative pathogen in children under 4 years of age. The French Pediatric Infectious Disease Group recommends in children > 3 months of age empirical antibiotic therapy with appropriate coverage against methicillin-sensitive S. aureus with high doses (150mg/kg/day) of intravenous amoxicillin-clavulanate, cefuroxime or cefazoline. In most children with uncomplicated BJI, short intravenous antibiotic therapy for 3 days can be followed by oral therapy. The minimum total duration of antibiotic therapy should be 10 days for septic arthritis and 3 weeks for osteomyelitis.


Asunto(s)
Antibacterianos/uso terapéutico , Artritis Infecciosa/tratamiento farmacológico , Artritis Infecciosa/microbiología , Infecciones Bacterianas/tratamiento farmacológico , Osteomielitis/tratamiento farmacológico , Osteomielitis/microbiología , Niño , Humanos
12.
Arch Pediatr ; 24(12S): S52-S60, 2017 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-29290236

RESUMEN

This section summarizes the empirical antimicrobial treatment according to the less frequent bacterial species responsible for infection whether community-acquired or nosocomial. It specifies their role in diseases and the recommended antibiotics, taking into account their natural and most common acquired resistance and the pharmacokinetic-pharmacodynamic parameters. The advice of an infectious disease specialist or bacteriologist is recommended.


Asunto(s)
Antibacterianos/uso terapéutico , Bacterias/aislamiento & purificación , Infecciones Bacterianas/tratamiento farmacológico , Infecciones Bacterianas/microbiología , Niño , Humanos , Guías de Práctica Clínica como Asunto
14.
Clin Microbiol Infect ; 22(8): 737.e9-737.e15, 2016 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-27287887

RESUMEN

Group A rotavirus (RVA) is the leading cause of acute gastroenteritis in young children worldwide. A prospective surveillance network has been set up to investigate the virological and clinical features of RVA infections and to detect the emergence of potentially epidemic strains in France. From 2009 to 2014, RVA-positive stool samples were collected from 4800 children <5 years old attending the paediatric emergency units of 16 large hospitals. Rotaviruses were then genotyped by RT-PCR with regard to their outer capsid proteins VP4 and VP7. Genotyping of 4708 RVA showed that G1P[8] strains (62.2%) were predominant. The incidence of G9P[8] (11.5%), G3P[8] (10.4%) and G2P[4] (6.6%) strains varied considerably, whereas G4P[8] (2.7%) strains were circulating mostly locally. Of note, G12P[8] (1.6%) strains emerged during the seasons 2011-12 and 2012-13 with 4.1% and 3.0% prevalence, respectively. Overall, 40 possible zoonotic reassortants, such as G6 (33.3%) and G8 (15.4%) strains, were detected, and were mostly associated with P[6] (67.5%). Analysis of clinical records of 624 hospitalized children and severity scores from 282 of them showed no difference in clinical manifestations or severity in relation to the genotype. The relative stability of RVA genotypes currently co-circulating and the large predominance of P[8] type strains may ensure vaccine effectiveness in France. The surveillance will continue to monitor the emergence of new reassortants that might not respond to current vaccines, all the more so as all genotypes can cause severe infections in infants.


Asunto(s)
Enfermedades Transmisibles Emergentes , Servicio de Urgencia en Hospital , Infecciones por Rotavirus/epidemiología , Infecciones por Rotavirus/virología , Rotavirus/genética , Animales , Preescolar , Heces/virología , Femenino , Francia/epidemiología , Genotipo , Humanos , Lactante , Recién Nacido , Masculino , Filogenia , Prevalencia , Virus Reordenados , Rotavirus/clasificación , Rotavirus/aislamiento & purificación , Infecciones por Rotavirus/diagnóstico , Estaciones del Año , Índice de Severidad de la Enfermedad
15.
Nano Lett ; 16(4): 2363-8, 2016 Apr 13.
Artículo en Inglés | MEDLINE | ID: mdl-26998817

RESUMEN

Resonant Raman spectroscopy is a powerful tool for providing information about excitons and exciton-phonon coupling in two-dimensional materials. We present here resonant Raman experiments of single-layered WS2 and WSe2 using more than 25 laser lines. The Raman excitation profiles of both materials show unexpected differences. All Raman features of WS2 monolayers are enhanced by the first-optical excitations (with an asymmetric response for the spin-orbit related XA and XB excitons), whereas Raman bands of WSe2 are not enhanced at XA/B energies. Such an intriguing phenomenon is addressed by DFT calculations and by solving the Bethe-Salpeter equation. These two materials are very similar. They prefer the same crystal arrangement, and their electronic structure is akin, with comparable spin-orbit coupling. However, we reveal that WS2 and WSe2 exhibit quite different exciton-phonon interactions. In this sense, we demonstrate that the interaction between XC and XA excitons with phonons explains the different Raman responses of WS2 and WSe2, and the absence of Raman enhancement for the WSe2 modes at XA/B energies. These results reveal unusual exciton-phonon interactions and open new avenues for understanding the two-dimensional materials physics, where weak interactions play a key role coupling different degrees of freedom (spin, optic, and electronic).

16.
J Chem Phys ; 143(10): 102813, 2015 Sep 14.
Artículo en Inglés | MEDLINE | ID: mdl-26374006

RESUMEN

The renormalization of electronic eigenenergies due to electron-phonon coupling (temperature dependence and zero-point motion effect) is sizable in many materials with light atoms. This effect, often neglected in ab initio calculations, can be computed using the perturbation-based Allen-Heine-Cardona theory in the adiabatic or non-adiabatic harmonic approximation. After a short description of the recent progresses in this field and a brief overview of the theory, we focus on the issue of phonon wavevector sampling convergence, until now poorly understood. Indeed, the renormalization is obtained numerically through a slowly converging q-point integration. For non-zero Born effective charges, we show that a divergence appears in the electron-phonon matrix elements at q → Γ, leading to a divergence of the adiabatic renormalization at band extrema. This problem is exacerbated by the slow convergence of Born effective charges with electronic wavevector sampling, which leaves residual Born effective charges in ab initio calculations on materials that are physically devoid of such charges. Here, we propose a solution that improves this convergence. However, for materials where Born effective charges are physically non-zero, the divergence of the renormalization indicates a breakdown of the adiabatic harmonic approximation, which we assess here by switching to the non-adiabatic harmonic approximation. Also, we study the convergence behavior of the renormalization and develop reliable extrapolation schemes to obtain the converged results. Finally, the adiabatic and non-adiabatic theories, with corrections for the slow Born effective charge convergence problem (and the associated divergence) are applied to the study of five semiconductors and insulators: α-AlN, ß-AlN, BN, diamond, and silicon. For these five materials, we present the zero-point renormalization, temperature dependence, phonon-induced lifetime broadening, and the renormalized electronic band structure.

17.
Arch Pediatr ; 22(6): 665-71, 2015 Jun.
Artículo en Francés | MEDLINE | ID: mdl-25934607

RESUMEN

Urine dipsticks have to be used more frequently for the screening of urinary tract infections (UTI) in febrile infants and children (grade A). Confirmation of the UTI by urine culture should prefer other methods of sampling than the urine bag: sampling jet, urethral catheterization, or pubic puncture (grade A). The percentage of Escherichia coli producing extended-spectrum beta-lactamases (ESBL) in children accounts for less than 10 % in France and does not justify revising the 2007 recommendations (grade B). An increase in the use of carbapenems in first-line treatment is a major environmental hazard and exposes the patient to the risk of untreatable infections. For febrile UTI, the expert group recommended: (1) recover the results of susceptibility testing as soon as possible to quickly adapt treatment for possible resistant strains; (2) favor initial treatment with aminoglycosides (particularly amikacin) which remain active in the majority of ESBL strains for patients seen in the pediatric emergency department and/or hospital; (3) ceftriaxone (IV or IM) remains an appropriate treatment for patients seen in the emergency department or outpatient clinic because the percentage of ESBL-producing enterobacteria strains remains low; (4) use oral cefixime (grade B) in nonsevere cases and low-risk patients defined as age>3 months, general condition preserved, disease duration of fever<4 days, no associated comorbidity, and no history of urinary tract infection, uropathy, or prior antibiotic therapy in the last 3 months; (5) oral relay for parenteral treatment is guided by in vitro susceptibility testing, in an attempt to reduce the use of oral cephalosporins to limit the selection of resistant bacterial strains. The total duration of treatment recommended is usually 10 days. Except for special circumstances, there is no need to prescribe retrograde cystography or antibiotic prophylaxis after a first febrile urinary tract infection. For cystitis, the panel recommends systematic urinalysis and initial prescription before the results of the urine culture of one of the three following oral antibiotics: amoxicillin-clavulanate, cotrimoxazole, cefixime. The total duration of antibiotic treatment is 5days to tailor treatment based on clinical progression and antibiotic susceptibility.


Asunto(s)
Infecciones Bacterianas/diagnóstico , Infecciones Bacterianas/terapia , Infecciones Urinarias/diagnóstico , Infecciones Urinarias/terapia , Niño , Preescolar , Humanos , Lactante
18.
Arch Pediatr ; 21(8): 906-12, 2014 Aug.
Artículo en Francés | MEDLINE | ID: mdl-24957981

RESUMEN

Staphylococcus aureus and Streptococcus pyogenes are the two main bacteria involved in skin infections in children. Mild infections like limited impetigo and furonculosis should preferentially be treated by topical antibiotics (mupirocine or fucidic acid). Empiric antimicrobial therapy of dermohypodermitis consists in amoxicillin-clavulanate through oral route (80 mg/kg/d) or parenteral route (150 mg/kg amoxicillin per d. in 3-4 doses) for complicated features: risk factors of extension of the infection, sepsis or fast evolution. Clindamycin (40 mg/kg/d per d. in 3 doses) should be added to the beta-lactam treatment in case of toxinic shock, surgical necrotizing soft tissues or fasciitis infections.


Asunto(s)
Dermis , Enfermedades Cutáneas Bacterianas , Tejido Subcutáneo , Niño , Humanos , Enfermedades Cutáneas Bacterianas/diagnóstico , Enfermedades Cutáneas Bacterianas/terapia
19.
Arch Pediatr ; 21(3): 329-34, 2014 Mar.
Artículo en Francés | MEDLINE | ID: mdl-24512806

RESUMEN

In France, international adoption includes around to 90,000 children since 1980 and near 300,000 immigrant children were counted in 2008. This population is heterogeneous, according to age and country of origin, and its large number. It is not easy to completely and surely assess the vaccine status of the child. Due to a great variability of individual situations, it is not possible to have systematic and unchangeable rules. This article aims to give an update of catch-up vaccination of internationally adopted or refugee or migrant children in France. The vaccination status of a child who recently arrived in France is complex and has to be adapted to his country of origin. Some of them were never vaccinated whereas the vaccine status of others is uncertain or unknown. Three parameters have to be considered: the age of the child, the country of origin, and sometimes serology in the case of doubts of his vaccine status. Catch-up vaccination of foreign children has to be adapted to French vaccine recommendations, as a reference, and to vaccines already administered to the child.


Asunto(s)
Adopción , Refugiados , Migrantes , Vacunación/estadística & datos numéricos , Adolescente , Niño , Preescolar , Francia , Humanos , Lactante , Recién Nacido
20.
Clin Infect Dis ; 58(7): 918-24, 2014 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-24532543

RESUMEN

BACKGROUND: Pneumococcal serotypes 1, 3, 5, 7F, and 19A were the most implicated in community-acquired pneumonia (CAP) after implementation of 7-valent pneumococcal conjugate vaccine (PCV7). In France, the switch from PCV7 to 13-valent pneumococcal conjugate vaccine (PCV13) occurred in June 2010. An active surveillance network was set up to analyze the impact of PCV13 on CAP. METHODS: An observational prospective study performed in 8 pediatric emergency departments from June 2009 to May 2012 included all children between 1 month and 15 years of age with chest radiography-confirmed pneumonia. Three 1-year periods were defined: pre-PCV13, transitional, and post-PCV13. RESULTS: During the 3-year study period, among the 953 274 pediatric emergency visits, 5645 children with CAP were included. CAP with pleural effusion and documented pneumococcal CAP were diagnosed in 365 and 136 patients, respectively. Despite an increase (4.5%) in number of pediatric emergency visits, cases of CAP decreased by 16% (2060 to 1725) between pre- and post-PCV13 periods. The decrease reached 32% in infants in the same periods (757 to 516; P < .001). Between pre- and post-PCV13 periods, the proportion of CAP patients with a C-reactive protein level >120 mg/dL decreased from 41.3% to 29.7% (P < .001), the number of pleural effusion cases decreased by 53% (167 to 79; P < .001) and the number of pneumococcal CAP cases decreased by 63% (64 to 24; P = .002). The number of additional PCV13 serotypes identified decreased by 74% (27 to 7). CONCLUSIONS: Our data suggest a strong impact of PCV13 on CAP, pleural effusion, and documented pneumococcal pneumonia, particularly cases due to PCV13 serotypes.


Asunto(s)
Infecciones Comunitarias Adquiridas/prevención & control , Vacunas Neumococicas/uso terapéutico , Neumonía Neumocócica/prevención & control , Proteína C-Reactiva , Niño , Preescolar , Infecciones Comunitarias Adquiridas/epidemiología , Francia/epidemiología , Humanos , Lactante , Masculino , Neumonía Neumocócica/epidemiología , Estudios Prospectivos , Vacunas Conjugadas/uso terapéutico
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