Melittin induces in vitro death of Leishmania (Leishmania) infantum by triggering the cellular innate immune response

Background: Apis mellifera venom, which has already been recommended as an alternative anti-inflammatory treatment, may be also considered an important source of candidate molecules for biotechnological and biomedical uses, such as the treatment of parasitic diseases. Methods: Africanized honeybee venom from Apis mellifera was fractionated by RP-C18-HPLC and the obtained melittin was incubated with promastigotes and intracellular amastigotes of Leishmania (L.) infantum. Cytotoxicity to mice peritoneal macrophages was evaluated through mitochondrial oxidative activity. The production of anti-and pro-inflammatory cytokines, NO and H2O2 by macrophages was determined. Results: Promastigotes and intracellular amastigotes were susceptible to melittin (IC50 28.3 mu g.mL(-1) and 1.4 mu g.mL(-1), respectively), but also showed mammalian cell cytotoxicity with an IC50 value of 5.7 mu g.mL(-1). Uninfected macrophages treated with melittin increased the production of IL-10, TNF-alpha, NO and H2O2. Infected melittin-treated macrophages increased IL-12 production, but decreased the levels of IL-10, TNF-alpha, NO and H2O2. Conclusions: The results showed that melittin acts in vitro against promastigotes and intracellular amastigotes of Leishmania (L.) infantum. Furthermore, they can act indirectly on intracellular amastigotes through a macrophage immunomodulatory effect

Influência dos ritmos circadianos na temperatura corporal, no sistema cardiovascular, no desempenho psicomotor e neuromuscular / Influence of circadian rhythms in body temperature, cardiovascular system, psychomotor and neuromuscular performance

Objetivo. El ritmo circadiano consiste en los cambios cíclicos que ocurren en el período de 24 h, pudiendo interferir en el desempeño humano. El objetivo del presente fue comparar los resultados de las variables fisiológicas, neuromusculares y del tiempo de reacción obtenidos en diferentes horarios del día. Método. Los 30 voluntarios (15 hombres y 15 mujeres) realizaron un conjunto de pruebas por la mañana (10 h), tarde (16 h) y noche (20 h). Las variables analizadas fueron la temperatura corporal (temperatura oral), la frecuencia cardíaca, la presión arterial (sistólica y diastólica), el tiempo de reacción, la flexibilidad, la agilidad, la velocidad, la potencia muscular y la fuerza muscular. Resultados. En la mayoría de las variables estudiadas no fue constatada la variación circadiana. Sin embargo, en el grupo masculino, la temperatura corporal fue estadísticamente mayor por la tarde (36,3 ± 0,4 °C) y por la noche (36,4 ± 0,3 °C) en comparación con la mañana (35,9 ± 0,5 °C), y la agilidad fue estadísticamente menor (lo que refleja un mayor rendimiento) por la tarde (10,9 ± 0,8 s) en comparación con la mañana (11,4 ± 0,8 s). Mientras que en el grupo de mujeres, la presión arterial sistólica fue estadísticamente mayor por la mañana (111,7 ± 7 mmHg) en comparación con la tarde (107,7 ± 7 mmHg) y la impulsión vertical fue estadísticamente mayor por la tarde (37,3 ± 6,5 cm) en comparación con la mañana (35,3 ± 7,1 cm). Conclusión. Los datos sugieren que la respuesta de la mayoría de las variables estudiadas no sufren la influencia de la hora del día (10, 16 e 20 h)(AU)

Objective. The circadian rhythm consists on the cyclic changes that occur in the 24 h period, which might interfere in the human performance. The purpose of this study was to compare the results of the physiologic and neuromuscular variables and of the reaction time obtained in different times of the day. Method. The 30 volunteers (15 men and 15 women) performed a battery of tests in the morning (10 h), in the afternoon (16 h) and at night (20 h). The analyzed variables were the body temperature (oral temperature), heart rate, blood pressure (systolic and diastolic), reaction time, flexibility, agility, velocity (30 m sprint), the muscle power (medicine ball throw, long and sargent jump) and muscle strength. Results. In the majority of the studied variables there was no circadian variation. However, for the male group, body temperature was statiscally higher in the afternoon (36.3 ± 0.4 °C) and at night (36.4 ± 0.3 °C) compared morning (35. 9 ± 0.5 °C) and agility was statiscally lower (reflecting higher performance) in the afternoon (10.9 ± 0.8 sec) compared morning (11.4 ± 0.8 sec). While in the female group, systolic blood pressure was statiscally higher in the morning (111.7 ± 7 mmHg) compared afternoon (107.7 ± 7 mmHg) and vertical jump was statiscally higher in the afternoon (37.3 ± 6.5 cm) compared morning (35.3 ± 7.1 cm). Conclusion. The data suggest that the response of the majority of the studied variables, do not suffer influence of the time of day (10, 16 and 20 h)(AU)