Interacciones genotóxicas de mutágenos en mezclas binarias mediante ensayo cometa alcalino en linfocitos humanos / Interaction of mutagens in binary mixtures using the alkaline comet assay in human lymphocytes

Introducción. Los mutágenos contenidos en mezclas complejas presentan interacciones de sinergismo, aditivas o antagónicas. Se han desarrollado enfoques experimentales que permitan dilucidar el responsable de las interacciones en la mezcla. Objetivo. Desarrollar un diseño experimental para comprender los procesos que se llevan a cabo entre los compuestos presentes en las mezclas complejas. Materiales y métodos. Se expusieron linfocitos humanos a mezclas binarias de mutágenos B[a]P, DMBA, Trp-P-1 y MX durante una hora, con activación metabólica y sin ella. La viabilidad se evaluó con azul de tripano y, la genotoxicidad, con cometa alcalino. Resultados. Ningún hidrocarburo tuvo efecto con furanona. Con S9 y sin él, se observó que se presentaban interacciones tóxicas entre hidrocarburos. Se observó sinergismo sin S9 entre B[a]P y Trp-P-1 y, con actividad metabólica, entre DMBA y Trp-P-1. Sin S9 se observó interacción antagónica entre Trp-P-1 y DMBA y, con S9, entre Trp-P-1 y MX y entre MX y DMBA. Se observó un incremento dependiente de la dosis en la longitud de la cola. Hubo daño genotóxico medio y aumento de las células dañadas. Para todas las mezclas se pudo determinar la concentración mínima en la que se observaban efectos adversos y solo para algunas se determinó la concentración máxima en la cual no se observaron efectos adversos. Conclusión. Se hace un aporte para comprender los procesos que ocurren cuando en una mezcla hay presentes, al menos, dos mutágenos y se valida un modelo de análisis que permite dilucidar el compuesto que tiene efecto sobre otro. También, se demostró que según el tipo de compuestos en la mezcla, se tendrá o no un umbral de riesgo.

Introduction. Mutagens contained in complex mixtures can present synergistic interactions, either additive or antagonistic. Therefore, development of experimental approaches is necessary to elucidate which is the responsible agent for the effect in the mixtures. Objective. An experimental design was developed that allowed an understanding of the processes between the compounds of complex mixtures. Materials and methods. Human lymphocytes were exposed to binary mixtures of the mutagens B[a]P, DMBA, Trp-P-1 and MX for 1 hour with or without S9. Viability was assessed with trypan blue dye and the genotoxicity by the comet assay. Results. All of the hydrocarbon showed an effect with furanone. With and without S9, the most toxic interactions were observed between hydrocarbons. Synergistic interaction was observed without S9 between B [a] P and Trp-P-1 and between DMBA and Trp-P-1 with metabolic activity. Without S9 antagonistic interaction was observed only between Trp-P-1+DMBA, and with S9 between Trp-P-1+MX and MX+DMBA. It observed an increase dose dependent in tail length. Half the cultures showed genotoxic damage and increased cell damage. For each mixture, minimum concentrations were determined at which adverse effects are observed; for some only the maximum concentration was determined at which no adverse effects are observed. Conclusion. The processes between mutagens present in a mixture have become better understood, and the results validated an analytical model that determined which component had an effect on another. The results also showed that the type of compounds in the mixture determined whether or not a risk threshold was present.

Acute effect of phosphodiesterase type 5 inhibitor on serum oxidative status and prolidase activities in men with erectile dysfunction

OBJECTIVES: To investigate the acute effect of phosphodiesterase type 5 (PDE5) inhibitor on erectile dysfunction by evaluating serum oxidative status and prolidase activity. METHODS: Serum samples of 36 patients with erectile dysfunction and 30 control cases were analyzed for total antioxidant status, total oxidant status, and prolidase activity, before and after the administration of tadalafil citrate. RESULTS: Before and after tadalafil citrate administration, serum total antioxidant status, total oxidant status, and prolidase were 1.1+0.0 vs. 1.6 + 0.0 umol H2O2 Eq/L, 10.3+1.1 vs. 6.9 + 1.2 umol H2O2 Eq/L, and 236.4+19.5 vs. 228.2 + 19.2 U/L, respectively (p<0.0001 for all). CONCLUSIONS: Evaluation of serum oxidative status and prolidase activity confirmed the beneficial acute effects of PDE5 inhibitor in patients with erectile dysfunction.

[Evaluation of antidepressant activities of harmane, norharman and harmine in mice]

It has been reported that, the [R]-carboline alkaloids of peganum harmala seeds have a stimulatory action on serotonin and catecholamines releases in different brain regions. In addition, one of the most important pharmacological effects demonstrated for [R]- carbolines is a revesible inhibitory action on MAO-A. These findings suggest that - carbolines, should alleviate at least some of the signs of depression. The purpose of present study is to determine the antidepressant activity of [R]-carbolines harmane, norharmane and harmine. All experiments were carried out on male Swiss-Webster mice [25-30g]. The antidepressant activities of the [R]-carbolines were assessed using the forced swim test. This test is the most widely used tool for antidepressant activity preclinically. In this test, mice were placed into a cylinderical glass [25 cm height, 12 cm in diameter] containing a column of 15 cm of water at 25 +/- 1 [o]C. After 30 min of the-carbolines injections, the mice were subjected to forced swimming test for 8 min and their immobility time was recorded. Intraperitoneal [i.p.] injections of harmane [5-15 mg/kg], norharmane [2.5-10 mg/kg] and harmine [5-15 mg/kg] significantly decreased the immobility time in the mouse forced swim test. The inhibitory effects of harmane, norharmane and harmine were antagonized by flumazenil [5 mg/kg, i.p.] but not by reserpine [5 mg/kg, i.p., 18 h before test]. The results suggest that the antidepressant activities of harmane, norharmane and harmine may be mediated through an inverse agonistic mechanism

Carboline antifilarials: effects on carbohydrate metabolising enzymes in Litomosoides carinii female.

Two antifilarial compounds, viz., 90/55 (7-oxo-1-phenyl-8, 14-dihydropyrido (3,4-b) imidazo (1,2-c) quinazolo (4,5-g) and 87/639 (6-Nitro-1-phenyl-9H-pyrido (3,4-b) indole at 0.5 and 2.0 micron concentrations substantially inhibited glucose uptake and increased lactate production by L. carinii during in vitro incubation for 2 hr. The treated parasites, showed increased activities of glycogen phosphorylase, phosphofructokinase and pyruvate kinase. Hexokinase and fumarate reductase activities level in the worms were significantly lowered. Therefore it appears that both the compounds kill adult L. carinii by interfering with its carbohydrate metabolism.

Time-dependency for the effect of different stressors on rat pineal melatonin content

Este estudio describe el efecto de la forzada durante 15 min o la inyección i.p. de ß-carboline (ß-CCE) sobre el contenido pineal de melatonina. Ambos agentes estresantes fueron aplicados al final del período de luz (1800 h) o en el momento del máximo nocturno de melatonina (2200 h). A las 1800 h, ninguno de los procedimientos modificó los niveles de melatonina pineal, mientras que a las 2200 h ambos fueron efectivos. Sólo ß-CCE aumentó, y en forma no significativa, los niveles nocturnos de melatonina pineal cuando se la inyectó a las 1800 h. Ninguno de los dos agentes estresantes fue efectivo en revertir la inhibición del aumento nocturno de melatonina producido por la luz continua. En cambio, la privación de agua durante 2 días produjo un incremento de los niveles diurnos de melatonina a valores semejantes a los de la oscuridad, sin modificar los niveles nocturnos. La privación de alimentos durante 2 días no efectó los níveles de melatonina. Los presentes resultados indican que existen efectos diferenciales de los distintos tipos de estrés sobre la producción de melatonina pineal

Benzodiazepine inverse agonist, DMCM- and peripheral agonist, Ro 5-4864-induced convulsions in mice: effect of adenosinergic agents.

Adenosinergic agents such as adenosine, 2-chloro-adenosine, N6-cyclohexyladenosine produced dose-dependent protective effect against DMCM- and Ro 5-4864-induced convulsions and mortality. N6-cyclohexyladenosine produced most significant protective e ect against Ro 5-4864-induced convulsions whereas 2-chloroadenosine was more effective than N6-cyclohexyladenosine in antagonising DMCM-induced convulsions. Pretreatment of animals with subprotective doses of adenosine and dipyridamole significantly prolonged the latencies for the onset of myoclonic jerks and convulsions due to both DMCM and Ro 5-4864. DMCM and Ro 5-4864-induced mortality rate was also significantly reduced by pretreatment with subprotective doses of adenosine and dipyridamole. Similarly, subprotective doses of adenosine and diazepam further delayed the latencies for myoclonic jerks and convulsions due to DMCM and Ro 5-4864 treatment. The results suggest that adenosine and adenosine receptor agonists, 2-chloroadenosine and N6-cyclohexyladenosine are protective against both DMCM- and Ro 5-4864-induced convulsions. It is suggested that adenosinergic agents via activation of central A1 adenosine receptors may modulate the convulsant effects mediated by DMCM and Ro 5-4864. This study further supports the notion that adenosinergic mechanisms mediate neuroprotective e ects in the central nervous system.