Role of the sodium-dependent phosphate cotransporters and absorptive endocytosis in the uptake of low concentrations of uranium and its toxicity at higher concentrations in LLC-PK1 cells.

It has been suggested that uranium uptake and toxicity could be mediated by endocytosis and/or the type IIa sodium-dependent phosphate cotransporter (NaPi-IIa). The aim of this study was therefore to characterize in vitro the role of these two cellular mechanisms in the uptake and toxicity of low (200-3200 nM) and high (0.5 and 0.

Heterogeneous accumulation of uranium in the brain of rats.

Recent reports suggest that uranium can accumulate not only in known target organs, that is, kidneys or bones, but also in others such as central nervous system. In the present work, the accumulation of uranium in the brain of rats was studied after repeated exposure by inhalation, chronic exposure by ingestion and acute exposure by injection. For each route of administration, the amount of uranium entering the brain was low.

Comparison of the effects of enriched uranium and 137-cesium on the behaviour of rats after chronic exposure.

Purpose: A radionuclide that accumulates in the central nervous system is likely to exert both a chemical and a radiological effect. The present study aimed at assessing the behavioral effect of two radionuclides previously shown to accumulate in the central nervous system after chronic exposure--uranium and cesium.

Materials And Methods: Rats were exposed for 9 months to drinking water contaminated with either enriched uranium at a dosage of 40 mg U x l(-1) or 137-cesium at a dosage of 6500 Bq x l(-1), which correspond to the highest concentrations measured in some wells in the south of Finland (uranium) or in the milk in Belarus in the year following the Chernobyl accident (137-cesium).

Parental exposure to enriched uranium induced delayed hyperactivity in rat offspring.

Several recent reports suggest that chronic exposure to uranium could induce behavioural effects in adult rats. As the immature brains are known to be more susceptible to toxic effects, rats were observed in an open field, in a Y-maze and in an elevated plus-maze at 2, 5 and 9 months old after exposure to enriched uranium (40 mg l-1) during gestation and lactation. The rats exposed to enriched uranium showed a significant decrease in alternation in the Y-maze at 2 months old which reflects a slight decrease in the spatial working memory capacities as previously described in adult rats.

Evaluation of the effect of chronic exposure to 137Cesium on sleep-wake cycle in rats.

Since the Chernobyl accident, the most significant problem for the population living in the contaminated areas is chronic exposure by ingestion of radionuclides, notably (137)Cs, a radioactive isotope of cesium. It can be found in the whole body, including the central nervous system. The present study aimed to assess the effect of (137)Cs on the central nervous system and notably on open-field activity and the electroencephalographic pattern.