Our data support a disproportion between free radicals levels and scavenging systems activity in different cerebral regions of the aging rat. We investigated the total reactive antioxidant potential and reactivity levels, which represent the total antioxidant capacity, in different cerebral regions of the aging rat (cortex, striatum, hippocampus and the cerebellum). In addition, we have determined several oxidative stress parameters, specifically the free radicals levels, the macromolecules damage (lipid peroxidation and carbonyl content), as well as the antioxidant enzymes activities in different cerebral areas from young (2 months-old), mature adult (6 months-old) and old (24 months-old) male Wistar rats. Free radicals levels, determined by 2',7'-dichlorofluorescein diacetate probe, were higher in striatum, cerebellum and hippocampus from aged rats. There was an age-related increase in lipoperoxidation in hippocampus and cerebral cortex. In the cerebellum, a high activity of superoxide dismutase and a decrease of catalase activity were observed. The striatum exhibited a significant catalase activity decrease; and glutathione peroxidase activity was diminished in the hippocampus of mature and aged rats. There was a marked decrease of total antioxidant capacity in hippocampus in both reactivity and potential levels, whereas striatum and cerebral cortex displayed a reduction on reactivity assay. We suggest that age-related variations of total antioxidant defenses in brain may predispose structures to oxidative stress-related neurodegenerative disorders.

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This is a pioneering study that examines the nutritional status of crack users. Our results showed that most crack users present normal anthropometric findings and the prevalence of underweight is low. However, blood analysis showed changes and a specific type of malnutrition.

Tissue accumulation of L-phenylalanine (Phe) is the biochemical hallmark of human phenylketonuria (PKU), an inherited metabolic disorder clinically characterized by mental retardation and other neurological features. The mechanisms of brain damage observed in this disorder are poorly understood. In the present study we investigated some oxidative stress parameters in the brain of rats with experimental hyperphenylalaninemia. Chemiluminescence, total radical-trapping antioxidant potential (TRAP), superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GSH-Px) activities were measured in the brain of the animals. We observed that chemiluminescence is increased and TRAP is reduced in the brain of hyperphenylalaninemic rats. Similar data were obtained in the in vitro experiments using Phe at various concentrations. CAT activity was significantly inhibited by Phe in vitro and in vivo, whereas GSH-Px activity was reduced in vivo but not in vitro and SOD activity was not altered by any treatment. The results indicate that oxidative stress may be involved in the neuropathology of PKU. However, further studies are necessary to confirm and extend our findings to the human condition and also to determine whether an antioxidant therapy may be of benefit to these patients.

Histamine exerts its action in smooth muscle via in two types of receptors. In coronary arteries of pigs both types of receptors are also involved in responses to histamine. Histamine initiates by an interaction with H1-receptors a contraction and with H2-receptors a relaxation. The histamine-induced contraction is reduced by the competitively antagonistic action of mepyramine. Metiamide potentiates dose-dependently the histamine-caused contraction in the absence and presence of mepyramine. The proportion of H2-receptors in relation to H1-receptors is calculated.

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