Antibacterial efficacy of nisin, bacteriophage P100 and sodium lactate against Listeria monocytogenes in ready-to-eat sliced pork ham

ABSTRACT The effectiveness of bacteriophage P100, nisin and sodium lactate, individually and in combination, in inhibiting Listeria monocytogenes in ready-to-eat pork ham slices was assessed. The antimicrobials were applied to the surfaces of ready-to-eat pork ham slices, which were inoculated with a mixture of L. monocytogenes. Among the individual antimicrobial treatments, bacteriophage P100 was the most effective, decreasing L. monocytogenes to undetectable levels at zero and 72 h post-infection. Sodium lactate was the least effective treatment. Treatment with nisin at zero h significantly reduced initial cell density (p < 0.05). However, this pattern was not observed at 72 h of storage. A significant difference (p < 0.05) existed between the results of separate bacteriophage and nisin treatments after refrigerated storage, but not immediately upon inoculation of the bacteria. The results showed that the use of bacteriophage P100 is the method of choice for the control of bacteria.

Fighting by sleep-deprived rats as a possible manifestation of panic: effects of sodium lactate

Increased fighting is an effect of desynchronized sleep deprivation (DSD) in rats, and recently this behavior has been suggested to be spontaneous panic and equivalent to panic disorder. In the present study we tested this hypothesis by evaluating the effect of sodium lactate on this aggressiveness, because this substance is recognized to induce spontaneous panic attacks in patients. A total of 186 male albino Wistar rats, 250-350 g, 90-120 days of age, were submitted to DSD (multiple platform method) for 0, 4, or 5 days. At the end of the deprivation period the rats were divided into subgroups respectively injected intraperitoneally with 1.86, 2.98 and 3.72 g/kg of 1 M sodium lactate, or 1.86 and 3.72 g/kg of 2 M sodium lactate. The control animals were submitted to the same procedures but received equivalent injections of sodium chloride. Regardless of DSD time, sleep-deprived animals that received sodium lactate presented a significantly higher mean number of fights (0.13 + or - 0.02 fights/min) and a longer mean time spent in confrontation (2.43 + or - 0.66 s/min) than the controls (0.01 + or - 0.006 fights/min and 0.12 + or - 0.07 s/min, respectively; P<0.01, Student t-test). For the sodium lactate group, concentration of the solution and time of deprivation increased the number of fights, with the mean number of fights and mean duration of fighting episodes being greater with the 2.98 g/kg dose using 1 M lactate concentration. These results support the hypothesis that fighting induced by DSD is probably a spontaneous panic manifestation. However, additional investigations are necessary in order to accept this as a promising animal model for studies on panic disorder

Disociación de la respuesta de alarma ante una mezcla de cristaloides y coloides en la inducción anestésica en cirugía cardíaca

El objetivo de la investigación fue probar si la administración de líquidos durante la inducción de la anestesia, al restaurar el déficit de agua y expandirel volumen intravascular, atenuaria la respuesta hormonal normalmente producida en cirugía. Se realizó un estudio randomizado controlado, en un centro de atención terciaria, en treinta y seis pacientes programados para cirugía electiva de bypass aorto-coronario. Los criterios- de exclusión fueron: función miocárdica severamente- reducida o disfunción renal conocida. Doce pacientes recibieron 10 ml/kg de solución Ringer (grupo baja dosis de cristaloide LDC), 12 pacientes recibieron 15 ml/kg solución Ringer (grupo alta dosis de cristaloide HDC), y 12 pacientes recibieron una combinación de 10 ml/kg de solución Ringer más 10 ml/kg1 de solución hidroxietil-starch (HES) 450.000 daltons, grado de substitución 0,7 (grupo C-HES), dentro de un período de 20 minutos posterior a la inducción de la anestesia (fentanyl, midazolam, pancuronio). El índice cardíaco y el índice sistólico se incrementaron en 20 por ciento y 15 por ciento en el grupo C-HES mientras de al ADH, la renina y la aldosterona disminuyeron (18 por ciento, 18 por ciento, 43 por ciento) respectivamente, luego de la administración de volumen. Luego de la administración de volumen, los niveles plasmáticos de lso sistemas hormonales llamados a responder ante la deshidratación e hipovolemia disminuyeron en el grupo C-HES. En los otros dos grupos no se presentó ninguna mejoría del estado hemodinámico y las hormonas medidas permanecieron en el mismo nivel observado durante la inducción de la anestesia. No hubo diferencias intergrupales en el volumen total administrado o en l balance hídrico al final de la cirugía. La administración de una combinación de soluciones cristaloides y coloides siguiendo la inducción de la anestesia en pacientes con función ventricular preservada, programados para cirugía cardíaca, conduce a atenuar las respuesta normal de los sistemas hormonales que se observa durante los estados de deshidratación e hipovolemia, en tanto que la restricción de líquidos promueve la actividad de dichos sistemas hormales