FOCUS: fast Monte Carlo approach to coherence of undulator sources.

FOCUS (Fast Monte CarlO approach to Coherence of Undulator Sources) is a new GPU-based simulation code to compute the transverse coherence of undulator radiation from ultra-relativistic electrons. The core structure of the code, which is written in the language C++ accelerated with CUDA, combines an analytical description of the emitted electric fields and massively parallel computations on GPUs. The combination is rigorously justified by a statistical description of synchrotron radiation based on a Fourier optics approach. FOCUS is validated by direct comparison with multi-electron Synchrotron Radiation Workshop (SRW) simulations, evidencing a reduction in computation times by up to five orders of magnitude on a consumer laptop. FOCUS is then applied to systematically study the transverse coherence in typical third- and fourth-generation facilities, highlighting peculiar features of undulator sources close to the diffraction limit. FOCUS is aimed at fast evaluation of the transverse coherence of undulator radiation as a function of the electron beam parameters, to support and help prepare more advanced and detailed numerical simulations with traditional codes like SRW.

Azithromycin is more allergenic than clarithromycin in children with suspected hypersensitivity reaction to macrolides.

BACKGROUND: Macrolides are considered safe antibiotics with reduced allergenic activity. However, studies on the safety of macrolides are scarce, particularly in children. OBJECTIVE: The aim of this study was to assess the frequency of hypersensitivity reactions to clarithromycin and azithromycin in a group of children referred to our allergy unit for suspected macrolide allergy. METHODS: We retrospectively reviewed the charts of 90 children aged 1-17 years with symptoms suggestive of hypersensitivity reaction to clarithromycin or azithromycin between December 31, 2008 and December 31, 2013. The allergy workup included skin tests (ie, skin prick tests and/or intradermal tests), determination of serum specific IgE (sIgE) to clarithromycin and azithromycin, and, if necessary to reach a diagnosis, oral provocation tests. RESULTS: Seventy-seven children completed the allergy workup. A reaction to clarithromycin was recorded in 58 children (75.3%): 21 (36.2%) had a history of immediate reactions, and 37 (63.8%) had a history of nonimmediate reactions. A reaction to azithromycin was recorded in 19 children (24.6%): 6 (31.5%) had a history of immediate reaction, and 13 (68.42%) had a history of nonimmediate reaction. Positive results in skin tests and oral provocation tests with the suspect drug confirmed the diagnosis in 15.5% of reactions to clarithromycin (9 of 58) and in 47.3% of reactions to azithromycin (9 of 19) (P = .004). CONCLUSION: A complete allergy workup enabled us to confirm a diagnosis of clarithromycin and azithromycin allergy in 15.5% and 47.3% of cases, respectively. Azithromycin was more allergenic than clarithromycin in children.

Azithromycin is more allergenic than Clarithromycin in children with suspected hypersensitivity reaction to Macrolides

Background: Macrolides are considered safe antibiotics with reduced allergenic activity. However, studies on the safety of macrolides are scarce, particularly in children. Objective: The aim of this study was to assess the frequency of hypersensitivity reactions to clarithromycin and azithromycin in a group of children referred to our allergy unit for suspected macrolide allergy. Methods: We retrospectively reviewed the charts of 90 children aged 1-17 years with symptoms suggestive of hypersensitivity reaction to clarithromycin or azithromycin between December 31, 2008 and December 31, 2013. The allergy workup included skin tests (ie, skin prick tests and/or intradermal tests), determination of serum specific IgE (sIgE) to clarithromycin and azithromycin, and, if necessary to reach a diagnosis, oral provocation tests. Results: Seventy-seven children completed the allergy workup. A reaction to clarithromycin was recorded in 58 children (75.3%): 21 (36.2%) had a history of immediate reactions, and 37 (63.8%) had a history of nonimmediate reactions. A reaction to azithromycin was recorded in 19 children (24.6%): 6 (31.5%) had a history of immediate reaction, and 13 (68.42%) had a history of nonimmediate reaction. Positive results in skin tests and oral provocation tests with the suspect drug confirmed the diagnosis in 15.5% of reactions to clarithromycin (9 of 58) and in 47.3% of reactions to azithromycin (9 of 19) (P=.004). Conclusion: A complete allergy workup enabled us to confirm a diagnosis of clarithromycin and azithromycin allergy in 15.5% and 47.3% of cases, respectively. Azithromycin was more allergenic than clarithromycin in children (AU)

Antecedentes: A los macrólidos se les considera antibióticos seguros, con una reducida capacidad alergénica. Sin embargo, los estudios sobre este tema son insuficientes, especialmente en los niños. Objetivo: El objetivo de este estudio ha sido el evaluar la frecuencia de reacciones hipersensibilidad (HR) a claritromicina (clarithromycin) y a azitromicina (azithromycin) en un grupo de niños, estudiados en nuestra Unidad de Alergia, por sospecha de alergia a los macrólidos. Métodos: Se han estudiado restrospectivamente, 90 niños (de 1-17 años) con síntomas sugestivos de HR a clarithromycin o azithromycin, entre el 31 de diciembre de 2008 y 31 de diciembre de 2013. En el protocolo de estudio se incluyeron la realización de pruebas cutáneas intraepidérmicas (prick, SPT) y/o pruebas intradérmicas (ID)], la determinación de IgE sérica específica (sIgE) a clarithromycin y azithromycin y, si se consideraba necesario para llegar a un diagnóstico, pruebas de provocación oral (OPT). Resultados: Setenta y siete niños completaron el estudio. Cincuenta y ocho (75,3%) referían haber presentado reacciones a clarithromycin: 21 (36,2%) tenían antecedentes de reacciones inmediatas (IR), y 37 (63,8%) tenían antecedentes de reacciones no inmediatas (RIN). Diecinueve de los 77 niños (24,6%) habían presentado una reacción a azithromycin: 6 (31,5%) con una historia de IR y 13 (68,42%) con historia de NIR. Mediante pruebas cutáneas o por positividad en la OPT con el fármaco sospechoso, permitió confirmar el diagnóstico en 15,5% (9 de 58) de los casos de clarithromycin y en 47,3% (9 de 19) de los casos de azithromycin (p= 0,004). Conclusión: Un estudio alergológico completo permitió realizar un correcto diagnóstico de alergia a clarithromycin y azithromycin en 15,5% y 47,3% de los casos, respectivamente. En este trabajo, en niños, la azithromycin fue más alergénica que la clarithromycin (AU)