Desinfección de agua: acción comparativa del ozono y cloro sobre un amplio espectro bacteriano / [Water disinfection: comparative activities of ozone and chlorine on a wide spectrum of bacteria]

Ozone and chlorine are agents that disinfect by destroying, neutralizing or inhibiting the growth of pathogenic microorganisms. The treatment of drinking water with ozone has shown to be more efficient against spores of Bacillus subtilis. It was observed that the ozone already in dose of 0.35 mg/l produced the reduction of at least 5 log in populations of approximately 1 x 10(6) cells/ml of Escherichia coli, Vibrio cholerae, Salmonella typhi, Yersinia enterocolitica, Pseudomonas aeruginosa, Aeromonas hydrophila, Listeria monocytogenes and Staphylococcus aureus. With a dose of 0.50 mg/l of chlorine, the reduction was much smaller for the tested microorganisms (except Vibrio cholerae), while the effect of 2 mg/l of chlorine was similar to the ozone treatment. For spores of Bacillus subtilis, the reduction observed with ozone concentrations of 0.35 and 0.70 mg/l was of almost 3 log, while no considerable effect was obtained with chlorine in the tested conditions. Our results have shown that both disinfectans were consumed during the treatment period, probably because of the own water demand and the added bacterial mass.

Type I striated muscular fiber hypotrophy with central nuclei.

Las enfermedades neuromusculares son frecuente causa de hipotonia en la infancia. Entre las enfermedades neuromusculares congenitas, se destaca la hipotrofia tipo I con nucleos centrales. Se presenta un paciente de 7 1/2 anos, con una historia de hipotonia y retardo motor, afectado de esta enfermedad. El EMG revelo potenciales de corta duracion.La biopsia muscular demostro la presencia de hipotrofia de fibras tipo I con un alto porcentaje de nucleos centrales. Un defecto en la maduracion de las fibras tipo I secundario a un deficit metabolico o trofico de las motoneuronas tipo I, podria ser el mecanismo patogenico. La presencia o ausencia de areas claras centrales alrededor de los nucleos podria explicarse por la incidencia del corte y por el estado madurativo de la fibra en el momento de la biopsia. La heterogeneidad genetica, clinica e incluso histopatologica de los casos de la literatura sugieren la posibilidad de que existan muchas variantes de la misma entidad