Humio Tsunoda

Highly sensitive and rapid method for determination of fluoride ion concentrations in serum and urine using flow injection analysis with a fluoride ion-selective electrode

An apparatus for flow injection analysis (FIA) was developed to measure very low fluoride ion concentrations (<1 micromol/l). The analytical conditions of the apparatus were investigated, and the instrument was used to determine fluoride ion concentrations in serum and urine. All interferences caused by serum and urine matrices were eliminated using the proposed method. The recovery was almost 100.0% for serum and urine samples. The precision was within 4%. The results of determination of fluoride ion concentrations in the NIST Standard Reference Material of urine, SRM 2671a, agreed with the certified values. The detection limits in serum and urine were 0.016 and 0.16 micromol/l, respectively. The assay throughput was 15 samples/h in serum and 24 samples/h in urine. The mean fluoride ion concentrations in serum and urine samples from 53 young Japanese women were 0.383+/-0.158 micromol/l and 0.207+/-0.103 mg/g Cr, respectively. There was a significant correlation (r=0.39, p<0.01) between serum and urine fluoride ion concentrations.

Effect of matrix modifier and furnace material on the determination of traces of fluoride by electrothermal molecular absorption spectrometry of aluminum monofluoride

Abstract In the determination of fluoride by AlF absorbance measurements, the interference from strontium nitrate is avoided by using magnesium nitrate or barium nitrate added to aluminum solution as the matrix modifier. The effects of the graphite-furnace material on AlF absorbance are investigated. Glassy carbon and synthetic carbon gave longer furnace lifetimes and better sensitivity than the other materials tested. The maximum sensitivity (4.2 μg ml−1 fluoride for 0.0044 absorbance with a 10-μl injection) was obtained with synthetic carbon. The r.s.d, was

Determination of Submicrogram Quantities of Fluoride by a Rapid and Highly Sensitive Method

Abstract A new method has been developed for the determination of submicrogram quantities of fluoride. It consists of separating fluoride from the test sample by the pyrohydrolytic separation method and determination of the resulting aqueous HF solution by electrothermal molecular absorption spectrometry as aluminum monofluoride (AlF). This method is rapid, highly sensitive, and can be used for the determination of total (organic and inorganic) fluoride in various organic compounds and biological materials.

The relation between serum cytokine levels and common laboratory tests in healthy Japanese males.

ObjectivesCytokines are critical regulatory molecules that circulate in blood at measurable levels. However, the epidemiology of serum cytokine levels in healthy populations is still limited, particularly for Japanese populations. The objective of this study was to examine the relation between serum cytokine levels and common laboratory tests in a healthy Japanese population.MethodsWe studied serum levels of six cytokines (interleukin-4 (IL-4), IL-5, IL-6, IL-10, interferon-γ (IFN-γ), granulocyte-macrophage colony-stimulating factor (GM-CSF)) in a healthy Japanese population using a sensitive chemiluminescence ELISA (CL-ELISA). We examined the relations between serum cytokine levels and common laboratory tests using multiple regression analysis. We were particularly interested in potential relations between serum cytokine levels and C-reactive protein (CRP) in light of its relation to the risk of cardiovascular events. We also investigated the relation between cytokine levels, alcohol consumption and smoking.ResultsAfter adjusting for the influence of other cytokines and laboratory tests, the serum level of IL-4 was associated with IL-5 and GM-CSF. In addition to IL-4, IL-5 was also associated with IL-10 and IFN-γ. IL-6 was associated with IL-10 and IFN-γ, and IL-10 and IFN-γ were associated with GM-CSF. CRP was significantly negatively associated with serum IL-4 level. IL-6 was weakly correlated with alcohol consumption level in this population. IL-5 among smokers tended to be lower than that among nonsmokers.ConclusionsClose relations among serum cytokine levels were observed in a healthy population. It is interesting that the level of IL-4, an anti-inflammatory cytokine, was inversely related to CRP level, suggested to be a marker of inflammation.

Fluoride Absorption and Excretion in Human Subjects Following Ingestion of F-Contaminated Agricultural Products

Abstract Five volunteers participated in a study in which fluoride uptake and excretion were investigated following the ingestion of rice and green leafy vegetables produced in an area known to be polluted by airborne fluoride. The results were compared with those obtained from experiments in which the subjects were fed diets consisting of similar but non-contaminated foods. The average daily intake of fluoride by each participant was 7.84 mg when the subjects were on the experimental menu, while it was 1.89 mg when they were on the control menu. A high rate (92%) of fluoride absorption was observed when the subjects were on the experimental menu. The rate approximated that of NaF. In addition, the retention time of fluorides contained in the experimental meals was found to be longer than that of NaF. The importance of fluoride accumulation in agricultural products in relation to public health in Japan was discussed.

Prospective Survey on Fluoride Contents of Rice

Abstract A prospective 17-year survey was conducted on changes in fluoride content in unpolished rice from an area near an aluminum refinery plant. Rice samples were also taken for analysis from areas around various types of industries known to emit fluoride, and the results were compared with those obtained 10 years before. It was shown that unpolished rice readily accumulated airborne fluoride and that it could serve as an indicator for long-term and low level exposure to atmospheric fluoride. The fluoride contents of unpolished rice grown in areas around ceramics works were generally higher than those found in samples collected from other industrial areas. Although areas polluted by airborne fluoride emitted from ceramics works are limited to those surrounding the plants, many ceramics works lie scattered across Japan. It is possible, therefore, that ingestion of excessive amounts of fluoride-contaminated rice could become a serious public health problem. It is stressed that control measures should be taken to curb fluoride emission at ceramics works.

Gastrointestinal Absorption of Fluoride in Humans - A Comparative Study of NaF And CaF2

Abstract Twenty-three male subjects participated in a study in which differences in the gastrointestinal absorption of fluoride were examined based on changes in serum and urinary fluoride concentrations subsequent to ingestion of NaF or CaF 2 . Rapid fluoride absorption was observed with NaF, and the serum fluoride concentration reached a peak 30 minutes after fluoride administration. With CaF 2 , however, fluoride absorption was much lower than that of NaF, accounting for only eight to ten percent of the latter, and the serum fluoride level did not peak until two hours following its administration. A marked difference in the extent of fluoride absorption was also observed with CaF 2 , suggesting the presence of individual variation.

Dental Fluorosis Induced by Water-Borne Fluoride in the Effluent of an Aluminum Plant

Abstract Twenty-six cases of dental fluorosis (DF) including presumable cases were observed among young people (less than 24 years old) in a village where the air was slightly polluted by air-borne fluoride (F) from an aluminum plant. It was shown by an epidemiological study that streams in the village were contaminated by high levels of F from an effluent of the aluminum plant and the residents usually consumed these stream-waters daily, even for drinking purposes, without any knowledge of F pollution. The high level of F in the effluent resulted from a wet scrubber system in the plant.