Cadmium (Cd), a ubiquitous environmental pollutant, is a carcinogenic substance. Cd in the urine reflects an individual's cumulative exposure and the Cd concentration in the kidney. Inductively coupled plasma-mass spectrometry (ICP-MS) can detect Cd levels at the nanogram per liter level; however, mass spectral interference by molybdenum oxide (MoO) has been observed in biological samples. We developed an analytical method that did not include solid phase extraction ICP-MS (SPE-ICP-MS); rather, it used ICP-MS and octapole collision cell (OCC-ICPMS) technology using helium (He) gas. The measurement mass numbers were ¹¹¹Cd and ⁹⁸Mo, and we used ¹⁰³Rh as an internal standard. Method accuracy was assessed using reference urine (SRM 2670a; National Institute of Standards and Technology, Gaithersburg, MD, USA). The method detection and quantification limits of Cd in the urine were 0.0097 and 0.038 μg/L, respectively. Inter-day accuracy and precision were 100.7-102.4% and 0.9-4.9%, respectively. The analytical values of Cd and Mo in SRM 2670a reference urines obtained by the proposed method were within the allowable errors for the certified values. Significantly correlated Cd concentrations of urine samples from healthy 20 women was found between the present OCC-ICP-MS method and the SPE-ICP-MS method (r = 0.866). ICP-MS analysis using He as a collision gas is useful for determining low urinary Cd levels without requiring pretreatment.

View full abstract

Co-occurrence of zinc (Zn) deficiency and iron (Fe) deficiency is common in the world. However, investigations on simultaneous Zn and Fe deficiencies using experimental animals are limited, because of technical difficulties. We established Zn/Fe-deficient animal (rat) model in the previous study. We investigated effects of simultaneous Zn and Fe deficiency on plasma lipids and protein concentrations and enzyme activities. Forty 4-week-old male Sprague-Dawley rats were assigned into 4 dietary treatment groups of 10 each for the 4-week study: Fe-deficient group (FD), Zn-deficient group (ZD), Fe/Zn-deficient group (FZD), and control group (Control). The data were analyzed by SYSTAT ver. 10.2 and Statcel ver.2. The difference between groups was statistically tested by Tukey's simultaneous multiple comparison test and two-way ANOVA. P value less than 0.05 was considered significant. Plasma phospholipids were significantly affected by dietary iron level. Plasma phospholipids of FD and FZD were significantly decreased compared with ZD. Total protein and globulin concentration in plasma of FD were significantly increased compared with Control. Plasma Albumin/globulin ratio of ZD was significantly increased compared with FD. Plasma AST activity was significantly increased by iron deficiency, and plasma ALT activity was significantly increased by zinc deficiency. Plasma ACE activity of FD, ZD and FZD were significantly increased compared with Control.

View full abstract

A market basket survey for trace metal intake was carried out in Shizuoka city, Japan. Contents of 14 trace metals (Be, V, Cr, Mn, Co, Ni, Sr, Mo, Ag, Sn, Sb, Cs, Ba, and U) in food composites prepared from 154 food items of 20 food categories were analyzed by acid-digestion followed by ICP mass spectrometric determination. Trace metal concentrations were variable according to the 20 food composites; “Supplements & foods for specified health uses (S-FOSHU)”, “Algae” and “Nuts & seeds” were the composites in which many trace metals were found at higher concentration. The trace metal intake from each food category and total daily intake was estimated by multiplying trace metal concentration in the food composite and corresponding daily consumption statistics obtained from National Health and Nutrition Survey of Japan. Daily intake of trace metal was estimated from this survey to be 0.14 (0.064), 3.8 (3.5), 0.42 (0.33), 2.2 (1.9), 0.30 (0.29), 2.5 (2.5), and 0.56 (0.48) mg/day for Cr, Mn, Ni, Sr, Mo, Sn and Ba, respectively, and 2.6 (2.3), 36 (26), 15 (11), 2.8 (2.6), 1.7 (1.5), 8.0 (7.8), and 4.9 (2.0) μg/day for Be, V, Co, Ag, Sb, Cs and U, respectively (Since “S-FOSHU” substantially contributed to total daily intake of some metals but the representativeness of its contribution was not clear, total daily intake was estimated without “S-FOSHU” and shown in parenthesis). The estimated total daily intake was generally in agreement with the previously reported values. “S-FOSHU”, “Seasonings & spices” and “Vegetable” were the categories contributed much to total daily intake of many trace metals. Hazard quotient (HQ) was calculated for each metal based on Tolerable Daily Intake (TDI) proposed by US Environmental Protection Agency and other authorities. The HQ of Mo reached 1.0 and that for V, Mn, Ni and U was between 0.1 and 1.0, suggesting the necessity of screening of intake of these metals on individual basis to characterize more of their potential health risks.

View full abstract

In patients with a renal failure, control of the absorption of dietary phosphate is necessary to prevent hyperphosphataemia. Recently, it has been proposed that ferric citrate is used as a phosphate-binder for patients with renal failure. However, several recent studies have indicated that an accumulation of iron in liver causes cirrhosis and liver cancer. In the present study, we examined iron accumulation in tissues of rats administered a large amount of ferric citrate.
Male 4-week-old Wistar rats were fed AIN93G diet (basal diet) or the basal diet supplemented with 1.0 or 4.0% ferric citrate hydrate (FCH; iron content, 18.5%) for 4 weeks. Administration of 4.0% FCH significantly inhibited the rat growth. However, liver function and lipid metabolism were not influenced by the FCH administration. Fecal phosphorus excretion was dose-dependently increased by the FCH administration and serum phosphate was significantly lower in the 4% FCH group compared to the other two groups. Serum iron and transferrin saturation was dose-dependently increased by the FCH administration. In particular, transferrin saturation of the 4.0% FCH group was near 100%. Iron in the liver, kidney, spleen and femur were markedly increased by the FCH administration; in particular, the increase of the hepatic iron was proportional to the dietary iron concentration. In addition, hemosiderin was accumulated in the cytoplasm of liver. These results indicate that transferrin is saturated and siderosis is caused by oral administration of a large amount of ferric citrate.

View full abstract