Fluoride is ubiquitous in the environment. Fluoride are contained in air, soil, water, plants and animals. Human, therefore, intakes fluoride from air, drinking water and foods throughout the life. The fluoride absorption from gastrointestinal tract is rapid and complete in the absence of calcium, magnesium and aluminum. About 40 to 50% of absorbed fluoride is excreted to urine and residual fluoride is accumulated in bone. Fluoride has beneficial and adverse effects on tooth and bone. The adequate fluoride intakes decrease the prevalence of dental caries during the development of enamel minerals and stimulate migration of osteoblast of bone. On the other hand, excess intakes of fluoride cause dental fluorosis and skeletal fluorosis. Both fluoride concentrations in serum and bone were positively associated with age. The capacity of fluoride accumulation in bone is larger in younger than in older persons. Bone formation is predominant in younger persons, and bone resorption is predominant in elderly persons. It is expected that bone metabolism affects serum fluoride concentrations. The accumulated fluoride in bone thought to be released to serum by bone resorption in elderly persons. Previous studies showed a large inter-observer variation in the serum fluoride concentrations. Serum fluoride concentrations are affected by the analytical method, amounts of fluoride intake, the timing of collecting blood, kidney function and age. In the future study for serum fluoride concentrations, it is important to evaluate after adjusting confounding factors, especially age.

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Although inorganic arsenicals are toxic and carcinogenic in humans, inorganic arsenite (As^III) has recently emerged as a highly effective chemotherapeutic agent for acute promyelocytic leukemia (APL). Inorganic arsenicals are enzymatically methylated to weakly toxic dimethylarsinic acid (DMAs^V) that is a major pentavalent dimethylarsenic metabolite. Recent reports have indicated that trivalent methylarsenicals are produced through methylation of inorganic arsenicals and participate in arsenic poisoning. Trivalent methylarsenicals may be generated as arsenical-glutathione conjugates, such as dimethylarsinous glutathione (DMAs^IIIG), during the methylation process. However, less information is available on the cytolethality of DMAs^IIIG. We easily synthesized and purified DMAs^IIIG by a new high performance thin layer chromatography (HPTLC) method, and observed the cytolethality of the synthesized DMAs^IIIG using rat liver TRL 1215 cells. The cytolethality of DMAs^IIIG was very strong because of its high cellular uptake; its lethal concentration in vitro in 50% of the population (LC₅₀) was about 160 nM. We also found that DMAs^IIIG itself was not transported efficiently into the cells and was not cytotoxic; however it readily became strongly cytotoxic by dissociating into trivalent dimethylarsenicals and glutathione (GSH). The addition of GSH in micromolar physiological concentrations maintained the chemical form of DMAs^IIIG, and prevented DMAs^IIIG-induced strong cytolethality. Physiological concentrations of normal human serum (HS), human serum albumin (HSA), and human red blood cells (HRBC) also reduced both the cytolethality and cellular arsenic uptake induced by DMAs^IIIG exposure. These findings suggest that the significant cytolethality induced by DMAs^IIIG may never manifest in healthy humans even if DMAs^IIIG is formed in the body from inorganic arsenicals. This study may provide important information to determine the role of metabolic methylation and GSH in arsenic toxicity in patients with chronic arsenic poisoning who regularly ingest inorganic arsenic-contaminated well water and/or in APL patients who are injected with As^III as a chemotherapeutic agent.

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CueO is a multicopper oxidase involved in Cu-homeostasis of E. coli. CueO has the four catalytic copper binding sites, a type 1 Cu, a type 2 Cu and a pair of type 3 Cu's, in a single chain protein molecule consisting of 484 amino acids. CueO has the fifth Cu-binding site constructed by Met355, Asp360, Met439, Met439 as the substrate-binding site, which is isolated from bulk waters by the Met-rich segment comprised of amino acids 355-400. The high cuprous oxidose activity of CueO is realized by the presence of this fifth Cu-binding site as revealed by the K_m value and the point mutations for the ligating amino acids. CueO showed enhanced oxidizing activities for organic substrates in the presence of Cu(II) ion at the fifth Cu-binding site because this extra Cu(II) ion functioned as the mediator of electron-transfer between exogenous substrate and type 1 Cu. Further, mutations at Asp112 adjacent to the trinuclear Cu center formed by type 2 Cu and type 3 Cu's indicated that this acidic amino acid functioned not only as a proton donor for dioxygen but also as a modulator for the binding of dioxygen.

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In order to examine possible relationship between minerals and body mass index (BMI), we measured hair concentrations of 24 bio-elements including essential minerals and toxic metals in over 1500 male Japanese adults aged 20-60 years. Several essential minerals were found to be significantly high and positively or inversely correlated to BMI. The best BMI-correlated element was potassium (K) with the highest regression coefficient of r = 0.240, followed by mercury (Hg) (r = 0.207), molybdenum (Mo) (r = 0.202), sodium (Na) (r = 0.170), boron (B) (r = 0.144), selenium (Se) (r = 0.138) and aluminum (Al) (r = 0.131) with the p-value of p < 0.0000 for every element. Using the regression line of BMI = 2.23 Log Hg + 14.95 obtained, a 10-fold increase in mercury level was estimated to associate with a 2.2-point increment in BMI. The most inverse-correlated mineral to BMI was magnesium (Mg) (r = -0.264), followed by calcium (Ca) (r = -0.248) and zinc (Zn) (r = -0.166, p < 0.0000), which are representative competitive bio-elements against mercury. These findings suggest possibility that some minerals contribute to regulation of BMI, and higher dietary mercury intake is associated with the increase of BMI in male Japanese adults. Dietary intake of the competitive minerals against mercury, such as Mg, Ca and Zn, may be useful for controlling human body weights.

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Daily intakes of four essential trace elements (Cu, Fe, Mn, and Zn) in Ukrainian subjects were estimated in relation to the health effects on habitants after the Chernobyl accident. Two hundred and sixty-eight diet samples were collected from twenty-five oblasts (regions) using a duplicate portion method. The elements were determined by inductively coupled plasma atomic emission spectrometry (ICP-AES). For Ukrainians, median daily intakes of Cu, Fe, Mn, and Zn were 0.695, 7.87, 2.28, and 6.57 mg per person, respectively. The intakes of Cu, Fe, Mn, and Zn in Ukrainians were approximately two times lower than worldwide reported values.

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The biological function of nuclear copper in mammalian cells is poorly understood because little is known about specific binding protein(s) for nuclear copper. We recently purified that p54^nrb/Non-POU-domain-containing, octamer binding protein (p54^nrb/NonO) and polypyrimidine tract-binding protein-associated splicing factor (PSF), which are RNA- and DNA- binding multifunctinal nuclear proteins, from nuclear extracts of mice brain by immobilized metal affinity chromatography with copper ion (Cu-IMAC). In the present study, we purified both overexpressed p54^nrb/NonO and PSF in HEK 293 cells by Cu-IMAC. Scatchard plot analysis of copper binding to E. coli cells expressing recombinant p54^nrb/NonO protein revealed that the dissociation constant was 0.13 μM and the maximum binding number was 2.5 atoms per molecule of the recombinant protein. Using ultrafiltration assay, zinc ion is also shown to bind to the recombinant protein. However, zinc ion did not competitively inhibit the binding of copper to the recombinant protein. Moreover, p54^nrb/NonO protein did not bind specifically to other divalent heavy metals such as Cd²⁺, Mn²⁺, Pb²⁺, and Co²⁺.

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Cisplatin (CDDP) is an effective anticancer agent that is widely used in the treatment of testicular, ovarian, bladder and lung cancers. However the development of resistance to CDDP by tumor cells is a major obstacle to treatment. We reported that decreased accumulation of CDDP was observed in CDDP-resistant cell lines from NSCLC, and a good correlation was found between the amount of intracellular platinum and the sensitivity of lung cancer cell lines to CDDP. In the present study, to investigate the CDDP resistance mechanism, several platinum compounds were exposed to those cell lines, and we measured the cellular platinum using inductively coupled plasma mass spectrometry (ICP-MS). Furthermore, the proportion of intact CDDP in total platinum was also determined by LC-ICP-MS for pharmacokinetic study of CDDP.

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Zinc deficiency is becoming a subject of greater clinical interest than ever before, especially in an aging society. In 2002, many zinc deficient patients visited our clinic. To understand why so many were zinc deficient, we conducted surveys in 2003 and 2005, at our annual health examination, to study serum zinc (Zn) levels in local residents. We suspect that there are various local conditions that lower Zn level of these residents. We reported previously that a subject's Zn levels are affected by many factors, including the sampling time of day. So, we used only data taken from subjects whose blood sampled during morning hours in this paper. The data were analyzed to determine whether differences could be found in Zn levels of rural residents (in KI and NE areas) and urban residents (in TA, KA, and SH areas). The subjects come from two different studies: 308 from the 2003 Kitamimaki study and 1017 from the 2005 Tomi study. [SUMMARY] 1) Mean Zn levels of residents in KI (75.8μg/dl, the 2003 study) and NE (75.6μg/dl, 2005 study) were significantly lower than those found in urban areas, especially TA (78.3μg/dl) and KA (77.8μg/dl) in 2005. 2) Residents whose Zn was less than the lower limit of the standard Zn value were found in all age brackets. In NE (in the 2005 study) and KI (in 2003) rural areas, the percentage of residents whose Zn levels were less than the lower limit were 14.5% and 15.3% respectively. These rates were significantly higher than those in TA and KA. 3) In KI, mean Zn level found in 2005 (78.0μg/dl) was significantly higher than the level found in 2003. These figures tell us that residents in rural areas may have lower Zn levels than those in urban areas and that rural persons in poor health, including those who are of advanced age or who have experienced long illness, might easily become zinc deficient. To prevent zinc deficiency, we should use educational approaches that encourage people to alter eating and cooking habits and to farm the land in ways that promote and sustain healthy soil.

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Serum copper (Cu) levels have decreased by long-term administration of conventional Cu-poor enteral liquid foods in elderly inpatients. Therefore, enteral liquid foods with adequate Cu contents are desirable. In this study 9 inpatients (2 men, 7 women) with enteral liquid foods, aged 74±15 years (M±SD), were recruited, who suffered from cerebrovascular diseases and accepted either nasogastric tube in 6 cases or gastrostomy in 3 cases. Fasting blood sample was obtained early in the morning. Conventional Cu-poor liquid foods contained either 0.1 mg per 1,000 kcal in MA-8 or 0.12 mg in PN-Hi, while a novel L-8 (Asahi Kasei Pharma) did 0.8mg, similar to 0.7 - 0.8 mg of Cu over 70 years old in Dietary Reference Intakes for Japanese, 2005. During 24 months of L-8 administration, serum Cu and ceruloplasmin increased by ingested Cu of mean 0.80 mg, and serum selenium (Se) increased by ingested Se of mean 40μg, resulting in their normal levels from low levels. Serum molybdenum (Mo) and blood manganese (Mn) levels increased within normal ranges, while serum iron (Fe) and zinc (Zn) levels did not change significantly, though their baselines were underlimit. These above findings indicated that L-8 contained adequate Cu, Se, Mo and Mn. Further study is necessary for improving serum Fe and Zn levels in inpatients with enteral liquid foods.

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We examined normalizing effect for blood glucose levels of zinc(II) complex with 6-ethoxy picolinic acid (Zn(6-EtOpa)₂) on KK-A^y mice which used in this study as the model animals of type 2 diabetes, and compared with its ligand, 6-ethoxy picolinic acid (6-EtOpa). These mice were divided into three groups after the onset of diabetes at 8 weeks of age, which were an untreated group, a 6-EtOpa treated group, and a Zn(6-EtOpa)₂ treated group. They were given daily intraperitoneal (i.p.) injections of each material for a period of 2 weeks from 8th to 10th week of ages. The dose of Zn(6-EtOpa)₂ was 3 mg Zn/kg of body weight. Each animal was examined for its body weight, food intake, blood glucose level, glucose tolerance, HbA_1c level, hematological status, organ weight, and zinc and copper concentrations in the organs. After 2 weeks of administration, the blood glucose level of KK-A^y mice treated with Zn(6-EtOpa)₂ showed a significant decrease compared to both of the 6-EtOpa and control groups. Furthermore, the mice treated with Zn(6-EtOpa)₂ showed decreasing effect on HbA_1c levels and increasing effect on glucose tolerance. Zinc (II) concentration in the femur was significantly increased in the Zn(6-EtOpa)₂ treated group compared to the both of 6-EtOpa and control groups. Copper concentration was decreased significantly in both of femur and femoris muscle.

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