Imaging measurement methods are powerful tools to visualize the distribution and function of trace elements in living systems. A number of trace element imaging studies by radioisotopes and fluorescent probes have contributed to understand their essential roles. Recently, to investigate physiological roles of intrinsic trace elements, many efforts have been made to develop element-selective fluorescent probes such as Ca²⁺, Mg²⁺, Cu²⁺, etc. Zinc is also known to play important roles in biological processes. Although a variety of Zn²⁺-selective fluorescent probes has been developed, most of them presented so far possess a fluorescent core and a separate part for binding to Zn²⁺ within the molecule, so that the molecular weight is usually large and the molecules are hydrophobic. As a result, the applications of such molecules often face difficulties due to their low solubility in aqueous media. Thus, we developed lowmolecular-weight Zn²⁺ fluorescent probes based on a bipyridine scaffold to detect the Zn²⁺ levels in cellular systems.

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Previous studies have shown that iron (Fe) is essential for tyrosine hydroxylase (TH) activity and is a risk -factor for cognitive decline and brain atrophy. The senescence-accelerated mouse prone 10 (SAMP10) stain exhibits a decline of catecholamines, brain atrophy, and behavioral deterioration, such as dysfunctions in learning and memory, with advancing age. The purpose of this study was to elucidate the contribution of iron to catecholamine metabolism in the brains of SAMP10 mice.
Iron concentration was determined using an inductively coupled plasma mass spectrometer. Expression of the metal binding proteins ferritin, divalent metal transporter-1 (DMT1), and hepcidin was determined by western blot analysis.
The present study demonstrated that iron and ferritin levels in SAMP10 mice were significantly lower than that in control animals. DMT1 and hepcidin levels, however, did not differ significantly between SAMP10 and control mice. Our previous study showed that the decline in dopamine (DA) and norepinephrine (NE) concentrations in the cerebral cortex of SAMP10 mice is caused by downregulation of TH activity. Given that Fe is necessary for TH activity, our results suggest that a decrease in iron causes the decline of TH activity in the cerebral cortex of SAMP10 mice.

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Lanthanum (La) in the blood enters the portal blood circulation and may be excreted into the bile. The aim of the present investigation was to investigate the effect of La on hepatic function by means of clinical chemical analysis. The histological distribution of La in the liver was also studied. Rats were intravenously administrated with lanthanum chloride at five mg La/kg per week for five weeks. ALT and γ-GTP were not elevated in the blood of the experimented rats, while AST, LDH and ALP increased. The total serum bilirubin level was not increased after La administrations. These chemical data have shown little evidence of toxic effects on hepatic parenchymal cells. Since ALP is present in the epithelial cells lining the biliary collecting system, La excreted in bile may slightly effect on these cells. Histological observation revealed the accumulation of La in the Kupffer cells lining the hepatic sinusoids, but not in hepatic parenchymal cells. No degenerated hepatic cells were found after La administrations indicating little or no La toxicity to the liver.

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Food traceability systems are used to ensure food safety. The objective of this research was to develop a simple method to confirm the geographical authenticity of frozen taro. To characterize frozen taros according to their geographic origin and variety, 6 mineral and trace elements (Mg, Ca, Mn, Fe, Cu, and Zn) were determined in frozentaro samples using atomic absorption spectrophotometer (AAS). Mn, Cu, Ca and Mg concentration of frozen taro from China was higher than those from Japan. Liner discriminant analysis (LDA) was applied to discriminate the geographic origin between Japan and China. Using the established LDA model using 4 elements (Mn, Cu, Ca and Mg), 100% of samples were correctly determined. The results suggest that Chinese frozen taro could be distinguished from Japanese ones by determination of inorganic elements using AAS and by LDA using Microsoft Excel.

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