Mercury in blood cells—Altered elemental profiles

The study was composed of 27 persons that displayed vague symptoms similar to those of the victims of Minamata and Iraq. Skew distributions of mercury were observed in individual erythrocytes and neutrophil granulocytes when measured by PIXE. Mercury could not be detected in the platelets. The erythrocytes also displayed lowered concentrations of magnesium and zinc, together with increased concentrations of calcium and strontium. The neutrophils displayed decreased concentrations of magnesium and zinc and increased concentrations of calcium, strontium, and iron. The presence of mercury and the altered elemental profiles in the erythrocytes and the neutrophil granulocytes are suggested as early signs of exposure.     

Distribution of elements in rabbit liver lobule

The elemental composition of rabbit liver was determined by the PIXE and micro-PIXE methods. The mean concentrations of P, S, Cl, K, Fe, Cu, Zn, and Rb measured by both methods were similar. The latter method also allowed for localization of elements within lobule territory. It has been found that some elements are more prevalent in the veins (Cl, Fe) and others in the liver parenchyma (P, Cu, Zn). Moreover, Zn showed the characteristic intralobular distribution. Some methodological aspects of microbeam application to biological materials were also discussed.     

Intracellular changes of metal elements by fucoidan extracted from brown seaweed (Cladosiphon okamuranus)

This study was undertaken to elucidate the intracellular changes of metal elements after the administration of fucoidan extracted from Cladosiphon okamuranus. TRL1215 cells (normal rat liver cell line) were treated with 0, 0.1, or 1.0 mg/ml fucoidan and incubated in 5% CO2 at 37 degrees C. The cellular levels of Mg, Al, Fe, and Zn were significantly increased in the 1.0 mg/ml fucoidan-treated cells compared to those of the 0.1 mg/ml fucoidan-treated cells and the control. Next, TRL1215 cells were cultured on Mylar film overnight. At 24 h after 5-bromo-2'-deoxyuridine dosing, 0, 0.1, or 1.0 mg/ml fucoidan was treated for 9 h. The cellular distribution of elements was analyzed using in-air micro-micro-particle induced X-ray emission. The X-ray spectra showed that yields of Al, Mg, and Zn were high in order of the 1.0 mg/ml fucoidan-treated sample, the 0.1 mg/ml fucoidan-treated sample, and the control. Fe yield was mildly increased by fucoidan administration. In fucoidan-treated cells, the focal accumulation of Br was correlated spatially with phosphorous-rich region, suggesting that Br was localized within the nucleus. Al distribution provided a spatial association with Br map. These data suggest that fucoidan increases the accumulations of Al, Mg, Fe, and Zn in normal rat hepatocytes, and fucoidan-binding Al is postulated to be transferred into the nucleus.     

Trace-element determination in individual peripheral blood cells and possible diagnostic applications

Trace elements are indispensable for the effective and proper functioning of biological systems. Recent years have demonstrated the conspicuous lack of knowledge about trace-element physiology. Establishment of reference values is a very difficult task, requiring the consideration of and compensation for a number of possible simultaneous phenomena. Peripheral blood has been used in medical diagnosis for a very long time, because, among other things, it is easily accessible. In the search for signs of lack or excess of minerals and trace elements in disease, the interest has been focused mainly on blood plasma or serum. The utilization of blood cells as a marker model is proposed here. The advent of the nuclear microprobe made possible the determination of elemental profiles of individual cells. The techniques of blood cell separation and preparation for microprobe analysis are presented and discussed. As an example of a possible diagnostic application, a set of reference data from a control group is compared to corresponding data from a group of patients suffering from acute myeloid leukemia.     

Subcellular changes of essential metal shown by in-air micro-PIXE in oral cadmium-exposed mice

To clarify the relation of essential metals to cadmium (Cd) toxicity, we evaluated metallothionein expression and analyzed the subcellular distribution of essential metals using in-air micro-Particle-Induced X-ray Emission (PIXE). Four mice were dosed orally with 100 mg/L of Cd in drinking water for 1.5 or 2 years. Frozen samples of organs were used for micro-PIXE analysis and formalin-fixed samples were used for metallothionein staining. Immunohistochemically, metallothionein induction by 1.5y-Cd exposure was higher in the renal cortex than in the liver. Metallothionein expression was reduced after 2y-Cd administration compared to the 1.5y-Cd-exposed mice. Cd-induced tissue damage became marked in the 2y-Cd-exposed mice compared to the 1.5y-Cd-exposed mice, in which nephrotoxicity was more prominent than hepatotoxicity. Cd yield was higher in the renal cortex of the 2y-Cd-exposed mouse than in that of the 1.5y-Cd-exposed mouse, whereas no such increasing tendency was found in the liver. Compared to the control, the Cd-exposed mice markedly accumulated zinc in the liver and renal cortex. In the Cd-exposed mice, iron was mildly accumulated in the renal cortex and was slightly deprived in the liver. Elemental maps showed that a large amount of Cd was spatially combined with zinc in the 1.5y-Cd mouse. Free Cd became abundant in the 2y-Cd-exposed mouse. In addition, a small amount of Cd was colocalized with iron. The data suggest that zinc may contribute to protect against oral-administrated Cd toxicity, and impaired induction of MT may participate in hepato-nephrotoxicity of the 2y-Cd-exposed mouse.     

Interactions of selenium with metal ions at the cellular level

In a supplementation study in which organic selenium asl-selenomethionine was administered in low doses during 1 yr, alterations in the concentrations of metal ions in the erythrocytes and the neutrophil granulocytes were observed. In the erythrocytes, altered concentrations of zinc were parallel with selenium. The concentrations of magnesium, calcium, manganese, copper, and sulfur were not significantly altered. However, altered concentrations of iron and zinc were observed in the neutrophils. The concentrations of magnesium, calcium, manganese, copper, and sulfur were not significantly altered. The accumulation of selenium in individual blood cells was different from that obtained with supplementation of inorganic selenium. When organic selenium was supplemented, the thrombocytes accumulated more selenium than the erythrocytes and the neutrophil granulocytes. The observations indicate that selenium interacts with metal ions at the cellular level when supplemented in low doses. The chemical form of selenium might be important in nutrition and therapy in view of the interaction and distribution pattern at the cellular level.     

Study of the Spatial Distribution of Mercury in Roots of Vetiver Grass (Chrysopogon zizanioides) by Micro-Pixe Spectrometry

Localization of Hg in root tissues of vetiver grass (Chrysopogon zizanioides) was investigated by micro-Proton Induced X-ray Emission (PIXE) spectrometry to gain a better understanding of Hg uptake and its translocation to the aerial plant parts. Tillers of C. zizanioides were grown in a hydroponic culture for 3 weeks under controlled conditions and then exposed to Hg for 10 days with or without the addition of the chelators (NH₄)₂S₂O₃ or KI. These treatments were used to study the effects of these chelators on localization of Hg in the root tissues to allow better understanding of Hg uptake during its assisted-phytoextraction. Qualitative elemental micro-PIXE analysis revealed that Hg was mainly localized in the root epidermis and exodermis, tissues containing suberin in all Hg treatments. Hg at trace levels was localized in the vascular bundle when plants were treated with a mercury solution only. However, higher Hg concentrations were found when the solution also contained (NH₄)₂S₂O₃ or KI. This finding is consistent with the observed increase in Hg translocation to the aerial parts of the plants in the case of chemically induced Hg phytoextraction.     

Metals and seeds: Biochemical and molecular implications and their significance for seed germination

Seeds contain the embryo as a new plant in miniature and have two major functions, reproduction and dispersal. Seed formation completes the process of plant reproduction and, with seed germination, the next plant generation starts. Given the ever-increasing environmental pollution with metal(loid)s, it is perhaps surprising that relatively few reports detail the impacts of metals on seed metabolism, viability and germination in comparison to the numerous publications on the effects of metals in vegetative tissues, particularly roots and shoots. This review provides information on metal(loid) homeostasis, detoxification and tolerance in relation to seed metabolism and performance. The delivery of metals from the mother plant into seeds and their implications on seed development are discussed, as are their uptake upon seed imbibition and subsequent effects on seed germination. Implications for seeds and seedlings on the biochemical and molecular level are discussed and finally, applied aspects are considered regarding the use of seeds for soil and water purification, and in phytoremediation programmes. We conclude with a perspective on future metal research in relation to seed biology.