Nuevo sistema de bajo costo para adquisición y acondicionamiento de señales electrocardiográficas(AU)

Este trabajo aborda una alternativa de bajo costo para sistemas de adquisición de ECG con buena linealidad, alta robustez y repetibilidad. El sistema propuesto utiliza etapa de entrada y salida diferencial, moduladores PWM y diferenciador de señales digitales con una etapa de aislamiento conectada a un microcontrolador (MCS'51) como unidad de control para el procesamiento digital. La caracterización y los diferentes resultados de la etapa frontal muestran la simplicidad y ventajas de este nuevo sistema respecto al método clásico de adquisición de ECG. Esta alternativapuede ser usada en otros sistemas clínicos para adquirir diferentes variables fisiológicas tales como presión sanguínea, respiración, temperatura y otros(AU)

This paper shows a new low cost alternative for ECG acquisition system, with good linearity, high robustness and repeatability. The new system uses a differential input and output stage with TL062, PWM modulators (CI7556) and digital signals differentiator with isolation stage connected to a microcontroller (MCS'51) as control unit for digital processing. The front end was characterized and different results show the simplicity and advantages of this new system respect to classical ECGacquisition. This alternative will be use in other clinical systems to acquire different physiologic variables such as blood pressure, temperature and respiratory signal(AU)

[Value of agglutination tests for the rapid identification of isolated streptococci in medical microbiology]. / Intérêt des tests d'agglutination pour l'identification rapide des streptocoques isolés en microbiologie médicale.

The clinical need for rapidly and correctly differentiating pathogenic streptococci into Lancefield groups prompted the development of rapid agglutination techniques by the direct colony method. Pastorex Streptogroupe (Diagnostics Pasteur, France) and Streptex (Wellcome Diagnostics, USA) were tested on 90 streptococcal isolates and compared with the identification obtained by conventional procedures. No cross-reactions were observed with any of the 33 strains of enterococci and of the seven strains representative of other genus among Gram-positive bacteria. When combined with colonial morphology and hemolytic reaction, both Pastorex and Streptex were specific tests for identifying beta-hemolytic streptococci, with Pastorex being slightly faster.