Ana María Evangelista de Duffard

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Neonate rats were exposed to 100 mg/kg from the PND 7 to PND 25 or at 70 mg/kg from PND 12 to PND 25. Treated and control pups were subjected to several behavioral tests (righting reflex, negative geotaxy, forelimbs support and open field) during the period of treatment. At PND 25 the regional effects of 2,4-D on gangliosides composition and myelin(More)
Our results show that 2,4-dichlorophenoxyacetic acid (2,4-D) exposure through mother's milk during the period of rapid myelination (from the 15th to the 25th postnatal days) results in a myelin deficit in the pup's brain and demonstrates the vulnerability of the developing central nervous system (CNS) to 2,4-D. After 100 mg/kg 2,4-D administration to dams,(More)
Although the mechanism of 2,4-D neurotoxicity remains unknown the serotonergic system appears to mediate some of the effects of 2,4-D in rats as reported in our previous studies. In the present study we examine the concept that a challenge to a system may overcome compensatory mechanisms and thereby reveal otherwise hidden neurotoxicant-induced damage. We(More)
The purpose of this study was to determine whether the behavioral development pattern was altered by a pre- and postnatal exposure to 2,4-Dichlorophenoxyacetic acid (2,4-D). Pregnant rats were daily orally exposed to 70 mg/kg/day of 2,4-D from gestation day (GD) 16 to postnatal day (PND) 23. After weaning, the pups were assigned to one of the two subgroups:(More)
Behavioral end points are being used with greater frequency in neurotoxicology to detect and characterize the adverse effects of chemicals on the nervous system. Behavioral measures are particularly important for neurotoxicity risk assessment since many known neurotoxicants do not result in neuropathology. The chlorinated hydrocarbon class consists of a(More)
2,4-Dichlorophenoxyacetic acid (2,4-D), a worldwide-used herbicide, has been associated with a range of adverse health effects on humans and different animal species. Although the mechanism of 2,4-D neurotoxicity remains unknown, we had previously reported changes in various neurotransmitter systems, such as serotonin (5-HT) and dopamine (DA), which were(More)
Knowing early nutritional status have been shown to be an important factor in determining the activity level of rats later in life, we studied offspring of dams which had received 50, 70 or 700 mg/kg of 2,4-Dichlorophenoxyacetic acid (2,4-D) during nursing. Neonatal tissues and the stomach content (milk) were examined up to 16 post natal days to detect body(More)
The ability to identify potential neurotoxicants depends upon the characteristics of our test instruments. The neurotoxic properties of lead, methylmercury, polychlorinated biphenyls, and organic solvents would all have been detected at some dose level by tests in current use, provided that the doses were high enough and administered at an appropriate time(More)
Exposure to 2,4-dichlorophenoxyacetic acid (2,4-D) has several deleterious effects on the nervous system such as alterations in the concentrations of neurotransmitters in the brain and/or behavioral changes, myelination rate, ganglioside pattern [Bortolozzi, A., Duffard, R., Antonelli, M., Evangelista de Duffard, A.M., 2002. Increased sensitivity in(More)
2,4-Dichlorophenoxyacetic acid (2,4-D) is a herbicide widely used in the world and mainly excreted by the renal route in exposed humans and animals. Herbicides can affect other nontarget organisms, such as Escherichia coli. We observed that a single exposure to 1 mM 2,4-D diminished growth and total protein content in all E. coli strains tested in vitro. In(More)