Cerebral cortex and hippocampus respond differently after post-natal exposure to uranium.

The central nervous system (CNS) is known to be sensitive to pollutants during its development. Uranium (U) is a heavy metal that occurs naturally in the environment as a component of the earth's crust, and populations may therefore be chronically exposed to U through drinking water and food. Previous studies have shown that the CNS is a target of U in rats exposed in adulthood. We assessed the effects of U on behavior and cholinergic system of rats exposed from birth for 10 weeks at 10 mg.L⁻¹ or 40 mg.L⁻¹. For behavioral analysis, the sleep/wake cycle (recorded by telemetry), the object recognition memory and the spatial working memory (Y-maze) were evaluated. Acetylcholine (ACh) and acetylcholinesterase (AChE) levels were evaluated in the entorhinal cortex and hippocampus. At 40 mg.L⁻¹, U exposure impaired object recognition memory (-20%), but neither spatial working memory nor the sleep/wake cycle was impaired. A significant decrease was observed in both the ACh concentration (-14%) and AChE activity (-14%) in the entorhinal cortex, but not in the hippocampus. Any significant effect on behaviour and cholinergic system was observed at 10 mg U.L⁻¹. These results demonstrate that early exposure to U during postnatal life induces a structure cerebral-dependant cholinergic response and modifies such memory process in rats. This exposure to U early in life could have potential delayed effects in adulthood.

Cytokine status in Ukrainian children with irritable bowel syndrome residing in a radioactive contaminated area.

BACKGROUND: The effect of low dose radiation on immune system is shown. Ionizing radiation can affect cytokine production and polarization of T helper cells. OBJECTIVE: The current study focused on ionizing radiation in Ukrainian children residing in a contaminated area with clinical irritable bowel syndrome. METHOD: Our study included 75 rural children population aged 4-18 yrs, who lived in a contaminated area exposed to natural environmental radiation with clinical irritable bowel syndrome (categorized in three groups) and 20 rural children participants aged 5-15 yrs who were living in areas with similar levels of radioactive contamination without clinical irritable bowel syndrome as control group. Internal radiation activity was measured by gamma-ray spectrometry. Serum levels of IL-4 and IFN-γ were measured by enzyme linked immunosorbent assay. RESULTS: A trend towards increased levels of IL-4 was observed in children with clinical irritable bowel syndrome. In these children, IFN-γ levels were lower than that of the control group. CONCLUSION: The IBS symptoms in Ukrainian children residing in a contaminated area may have stemmed from Th1 to Th2 immune deviation and differential expression of IL-4 and IFN-γ.

Proposed standards for acute exposure to low enrichment uranium for compliance with 10 CFR 70.61.

Title 10, Code of Federal Regulations Part 70, puts forth requirements for licensure of special nuclear material including specific risk criteria for acute intakes based on biological effects. Standards for acute oral and inhalation intakes of soluble low enrichment are proposed for the three levels of biological effects given in the regulations. These levels were developed largely from available human data and have a large measure of conservatism. The proposed threshold for life endangerment was 500 mg for acute inhalation intakes and 2,500 mg for acute ingestion intakes. Acute intakes of 1,400 mg for ingestion and 100 mg for inhalation are proposed as thresholds for irreversible or serious long lasting health effects. For minor transient health effects, the proposed levels are 410 and 30 mg, respectively, for acute ingestion and inhalation intakes. For acute intakes below these levels, no demonstrable toxicological effects are anticipated.

Model results of kidney burdens from uranium intakes.

Uranium is a naturally occurring element, which is both radiologically and chemically toxic. When dealing with intakes of uranium, whether natural or depleted, chemical toxicity to the kidney usually predominates over radiological toxicity. This is especially true for uranium compounds in soluble (inhalation Type F) and moderately soluble (inhalation Type M) forms. To assess chemical toxicity, information on kidney burden per unit intake is required. This study summarizes the kidney burdens per unit intake for common exposures from uranium ingestion and inhalation. ICRP models developed for radiation dosimetry purposes can equally well be used to estimate kidney burdens from uranium intakes. While dosimetric quantities and data are tabulated in ICRP publications, data on uranium burdens in kidney are not explicitly given in these tabulations. In this work, the most recent ICRP models were utilized to generate a compilation of kidney burdens from common intakes. Calculations were made for four age groups from infant to adult. For all age groups, long-term chronic uranium ingestion will result in a kidney burden of 6.6% of daily uranium intake. Comparisons of kidney burdens due to acute ingestion and acute inhalation show that inhaled uranium compounds of Type F and Type M will generally result in higher burdens to kidney compared to the same amount of uranium compounds ingested.

Nuclear accident. World Health Organization.

After the nuclear accident in Chernobyl (U.S.S.R.) at the end of April, the Regional Office for Europe of the World Health Organization issued a statement about the precautions to be taken in Europe, the effects and the possible treatment.