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Usuda K.,Osaka Medical College | Kono R.,Osaka Medical College | Ueno T.,Osaka Medical College | Ito Y.,Osaka Medical College | And 4 more authors.
Biological Trace Element Research | Year: 2015

Various fluoride compounds are widely used in industry. The present risk assessment study was conducted using a series of inorganic binary fluorides of the type XFn, where Xn = Na+, K+, Li+, Mg2+, Ca2+, Sr2+, Ba2+, Al3+, Nd3+, La3+, Ce3+, Sm3+, Gd3+, Y3+, Yb2+, and Zn2+. The aqueous solutions of these salts were orally administrated to 16 experimental groups (one for each of the salts tested). The levels of fluoride, N-acetyl-β-d-glucosaminidase in cumulative 24-h urine samples and creatinine clearance were measured to assess possible acute renal damages. The levels of fluoride, alanine aminotransferase, and aspartate aminotransferase were also determined in serum samples to assess possible acute hepatic damages. The results reveal that sodium fluoride (NaF), potassium fluoride (KF), and zinc fluoride tetrahydrate (ZnF2 .4H2O) can carry the fluoride ion into the bloodstream and that it is excreted via urine more readily than the other compounds tested. These fluorides were assigned the highest risk impact factor. Most of the rare earth fluorides are insoluble in water while those groups 2 and 13 of the periodic table are slightly soluble, so that they do not have a significant negative risk. These findings suggest that the biological impact of fluoride depends on the accompanying counter ion and its solubility. The risk map obtained in the present study shows that the graphical visualization map technique employed is a valuable new tool to assess the toxicological risk of chemical compounds. © 2015, Springer Science+Business Media New York.


Usuda K.,Osaka Medical College | Ueno T.,Osaka Medical College | Ito Y.,Osaka Medical College | Dote T.,Osaka Medical College | And 3 more authors.
Biological Trace Element Research | Year: 2016

The present risk assessment study of fluoride salts was conducted by oral administration of three different doses of sodium and potassium fluorides (NaF, KF) and zinc fluoride tetrahydrate (ZnF2 •4H2O) to male Wistar rats. The rats were divided into control and nine experimental groups, to which oral injections of 0.5 mL distilled water and 0.5 mL of fluoride solutions, respectively, were given. The dosage of fluoride compounds was adjusted to contain 2.1 mg (low-dose group, LG), 4.3 mg (mid-dose group, MG), and 5.4 mg fluoride per 200 g rat body weight (high-dose group, HG) corresponding to 5, 10, and 12.5 % of LD50 values for NaF. The 24-h urine volume, N-acetyl-β-D-glucosaminidase (NAG) and creatinine clearance (Ccr) were measured as markers of possible acute renal impact. The levels of alanine aminotransferase (ALT) and aspartate aminotransferase (AST) were determined in serum samples as markers of acute hepatic impact. The levels of serum and urinary fluoride were determined to evaluate fluoride bioavailability. The results reveal that higher doses of NaF, KF, and ZnF2 induced renal damage as indicated by higher urinary NAG (p < 0.05 with ≥90th percentile of control). High doses of ZnF2 also induced a significant Ccr decrease (p < 0.05 with ≤10th percentile of control). Low doses of NaF and mid-doses of ZnF2 induced polyuria (p < 0.05 with ≥90th percentile of control) while medium doses of NaF and low doses of KF also induced liver damage, as indicated by a high level of AST (p < 0.05 with ≥90th percentile of control). These findings suggest that oral administration of fluoride is a potential, dose-dependent risk factor of renal tubular damage. © 2016 Springer Science+Business Media New York


Usuda K.,Osaka Medical College | Kono K.,Osaka Medical College | Ohnishi K.,Osaka Medical College | Nakayama S.,Osaka Medical College | And 7 more authors.
Toxicology and Industrial Health | Year: 2011

Chemicals are an essential part of modern manufacture processes. Their use must be managed with great attention in occupational settings to avoid serious detrimental effects to the health of employees. For example, cadmium compounds are indispensable for the production of nickel-cadmium rechargeable batteries or as chemical stabilizer in plastics. It is an exceptionally toxic heavy metal and personnel exposed to cadmium in the workplace meet with potential health risks that can lead to the development of kidney, skeletal and respiratory disorders. In consequence, proactive and systematical development of occupational hygiene and health activities are necessary to reduce chemical exposure to cadmium in the workplace. This review describes the known facts of cadmium toxicity, the biological effects of cadmium exposure, possible regulation measures to prevent occupational cadmium exposure in three industrial health management systems and discusses future cooperation programs in these systems, proactive safety activities and occupational safety and health management strategies. © The Author(s) 2011.


Usuda K.,Osaka Medical College | Kono R.,Osaka Medical College | Ueno T.,Osaka Medical College | Ito Y.,Osaka Medical College | And 4 more authors.
Biological Trace Element Research | Year: 2014

Rubidium has been considered to be nontoxic. Its use includes thin film on glass deposition and as medical contrast medium. Recent technology innovations also involve the use of rubidium, but there is limited information about the biological effects of its various compounds. In the present risk assessment study, a series of rubidium compounds with different counter anions-acetate, bromide, carbonate, chloride, and fluoride-were orally administrated in a single dose to several groups of rats. Cumulative 24-h urine samples were obtained, and the levels of rubidium, fluoride, N-acetyl-β-D-glucosaminidase and creatinine were measured to evaluate possible acute renal effects. Daily samples of serum were also obtained to determine the levels of aspartate and alanine aminotransferases to assess possible acute hepatic effects. Urinary rubidium excretion recovery of 8.0-10.5 % shows that urine can be a useful diagnostic tool for rubidium exposure. The present results reveal that rubidium shows different biological effects depending on the counter anion. A pattern of large significant NAG leakage and elevation of ALT observed in rats treated with anhydrous rubidium fluoride indicates renal and hepatic toxicities that can be attributed to fluoride. The techniques reported in this study will be of help to assess the potential risks of toxicity of rubidium compounds with a variety of anions. © 2014 Springer Science+Business Media.

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