Yumiko Nakamura

Differences in Behavior among the Chlorides of Seven Rare Earth Elements Administered Intravenously to Rats

Differences in behavior among the chlorides of seven rare earth elements (REEs)-yttrium (Y), cerium (Ce), and praseodymium (Pr) (light REEs); europium (Eu) and dysprosium (Dy) (medium REEs); ytterbium (Yb) and lutetium (Lu) (heavy REEs)-were investigated through intravenous administration of the REEs to rats. (1) Distributions of REEs and mineral concentrations in the organs on Day 1 were investigated at low and high doses (9-10 and 18-20 mg REE/kg, or 56-66 and 112-132 mumol REE/kg). More than 78% of the REEs administered was distributed into liver, bone, and spleen. High doses of Y, Eu, and Dy markedly increased the accumulation of REEs in spleen and lungs as well as the concentration of Ca in liver, spleen, and lungs. (2) The distribution patterns of REEs and changes in Ca concentrations in major organs over time were investigated by the administration of Pr, Eu, Dy, Yb (low dose), and Y (high dose). REEs disappeared from the blood within 1 day but were retained in the organs for a long time. The percentages of the doses of Y, Eu, Dy, and Yb found in the liver were highest at 8 hr to 2 days, then decreased gradually; hepatic Pr levels, however, remained high. Changes in Ca concentrations in liver, spleen, and lungs were in accordance with those of REEs. (3) Severe hepatotoxicity was observed after administration of Ce and Pr; fatty liver, jaundice, and elevated serum GOT and GPT levels were most prominent on Day 3. Therefore, we hypothesized that REE chlorides might be categorized into three groups according to their ionic radii (light REEs, Y and medium REEs, and heavy REEs) and from their behavior, i.e., distribution pattern, Ca-accumulating action, and hepatotoxicity.

Di(2-ethylhexyl) phthalate contamination of retail packed lunches caused by PVC gloves used in the preparation of foods.

Plasticizer contamination of foods sold in retail packed lunches and set lunches in restaurants was determined by GC/MS. The phthalate esters were as follows: diethyl, dipropyl, dibutyl, dipentyl, dihexyl, butylbenzyl, dicyclohexyl, di(2-ethylhexyl), dioctyl, diisooctyl (mixture of isomers) and diisononyl (mixture). Di(2- ethylhexyl) adipate was also determined. Sixteen packed lunches and ten set lunches were analysed, and in all samples the concentration of di(2-ethylhexyl) phthalate (DEHP) was the highest, at 0.80–11.8 mg/ kg in packed lunches and 0.012–0.30 mg/kg in set lunches. The DEHP content of five packed lunches exceeded 1.85 mg, which is the EU tolerable daily intake (TDI) for a person of 50 kg body weight. Foodstuffs that were components of the packed lunches were taken from the factory at each step of preparation and phthalates were determined. For example, chicken contained 0.08 mg/kg DEHP when uncooked, 13.1 mg/ kg after frying and 16.9 mg/kg after packing. Disposable PVC gloves used in the preparation of foods were apparently the source of high DEHP concentrations. The gloves used during cooking or packaging were sprayed with 68% (w/w) ethanol to sterilize them. PVC gloves from the factory contained 22 or 41% by weight of DEHP. To confirm the link with the contamination problem, samples of boiled rice, croquette and boiled dry radish were handled in the laboratory with PVC gloves containing 30% (w/w) DEHP. DEHP migration levels of 0.05 mg/kg in rice or 0.33 mg/kg in croquette, and 11.1 mg/kg in radish were found. The alcohol sprayed onto the gloves increased the migration of DEHP to 2.03 mg/kg in rice, 2.45 mg/ kg in croquette, and 18.4 mg/kg in radish.

Method for analysis of tannic acid and its metabolites in biological samples: Application to tannic acid metabolism in the rat

A new analytical method for measuring tannic acid (TA) using tannase was developed and applied to the investigation of TA metabolism in the rat following oral administration at a dose of 1.0 g/kg. The proposed method for TA determination was based on the enzymatic hydrolysis of TA to gallic acid (GA) and subsequent determination by HPLC. TA metabolites were determined by HPLC. 4-O-Methylgallic acid (4-OMGA), pyrogallol (PY), and resorcinol (RE) were detected in serum. TA was excreted into urine as GA (0.01%), 4-OMGA (0.10%), PY (0.24%), and RE (2.06%) and into feces as TA (62.74%), GA (0.19%), PY (0.02%), and RE (0.76%) within 54 h after oral administration. It was suggested that >60% of TA remained unchanged but that some was hydrolyzed to GA by tannase in the intestine and further metabolized to 4-OMGA, PY, and RE.

Intake of 1-deoxynojirimycin suppresses lipid accumulation through activation of the β-oxidation system in rat liver.

It was recently shown that administration of 1-deoxynojirimycin (DNJ) extracted from mulberry suppresses an increase in postprandial blood glucose in humans. These findings are of interest, but other physiological functions of DNJ are unknown. This study examined the effects of oral administration of DNJ (1 mg/kg of body weight/day) or mulberry extracts enriched in DNJ (meDNJ; 100 or 200 mg of extract/kg of body weight/day, equivalent to 0.53 or 1.06 mg of DNJ/kg of body weight/day) in male Sprague-Dawley rats for 4 weeks. DNJ and meDNJ enhanced expression of adiponectin mRNA in white adipose tissue; increased plasma adiponectin levels, enhanced expression of AMPK mRNA, activated the beta-oxidation system, and suppressed lipid accumulation in the liver. Intake of DNJ and meDNJ did not cause hepatic dysfunction and led to a reduction of oxidative stress. These results indicate the efficacy and safety of DNJ and meDNJ.

Effect of dietary squalene on the fecal steroid excretions and the lipid levels of serum and the liver in the rat

Abstract Effects of squalene on serum and hepatic lipid contents and fecal steroid excretion were examined in rat by chronic (0.01-0.1 mL/day, i.e. 8.622-86.22 mg/day) or single (0.1 mL/day, i.e. 86.22 mg/day) oral administration of squalene. With chronic administration of squalene, serum total, HDL-cholesterol, triglycerides and squalene did not change whereas serum phospholipids decreased with 0.1 mL/day of squalene administration. Hepatic total cholesterol and squalene did not changed. Fecal excretion of neutral steroids and bile acids were enhanced in the rats administered 0.1 mL/day of squalene. With single oral administration of squalene, the highest concentrations of squalene and cholesterol were observed at 6 hours in serum, and at 4 and 8 hours, respectively in the liver after squalene administration. Squalene was excreted into feces 35.1%, 6.8% and 0.42% of the administered dose at 0–1, 1–2 and 2–4 days, respectively. Neutral steroid excretion did not change though coprostanol excretion dereased significantly at 0–2 days. Bile acid excretion increased significantly at 1–2 days without change in cholic acid/chenodeoxycholic acid ratio. Oral administration of squalene have no effect on serum and hepatic lipids, but increased fecal bile acids and neutral steroid excretions.

調理用PVC製手袋使用規制後における市販弁当中のフタル酸エステル類及びアジピン酸ジ(2-エチルヘキシル)濃度

Ten samples of retail packed lunches purchased from convenience stores were determined for 11 phthalates and di(2-ethylhexyl) adipate (DEHA) in August 2000, 2 months after the prohibition of DEHP-containing PVC gloves in Japan. Each homogenized sample was extracted with acetonitrile, partitioned with n-hexane, and cleaned up using Florisil and PSA columns. Phthalates in the extract were determined by GC/MS (SIM). The limits of detection were 14.9 ng/g for di(2-ethylhexyl) phthalate (DEHP) and 18.6 ng/g for dibutyl phthalate (DBP). Levels of phthalates in packed lunch samples were 45 to 517 ng DEHP/g (198 ng/g, average), ND to 90 ng DEHA/g, and ND to 10.0 ng BBP/g. Diisononyl phthalate (DINP) was detected in one sample at 76 ng/g. Average DEHP level in ten samples was 4% of that in 1999. The contents of other phthalates were also reduced. DBP was not detected in any sample. Recovery of deuterated isomers added as surrogates was 27.9% for DNP-d4, and 40.6 to 101.5% for the other phthalates.

Analysis of Phenothrin and Its Metabolite 3-Phenoxybenzoic Acid (PBA) in Agricultural Products by GC and Ion-Trap GC/MS

A sensitive method for analysis of phenothrin and its metabolite 3-phenoxybenzoic acid (PBA) in agricultural products by gas chromatography with electron capture detection (ECD-GC) and ion-trap gas chromatography/mass spectrometry (GC/MS) with chemical ionization (Cl) was investigated. After phenothrin in vegetables, fruits, potatoes, starches, and tea had been extracted with acetone, or in cereals and beans had been extracted with acetonitrile followed by Florisi! column chromatography, it was reextracted into n-hexane. PBA was determined by ECD-GC after esterification with hexafluoroisopropyl alcohol (HFIP) and diisopropylcarbodiimide (DIC). Phenothrin was determined by monitoring its molecular ion peak using ion-trap GC/MS and was confirmed by observing its spectral pattern. The detection limit for phenothrin by ECD-GC and ion-trap GC/MS by this method was 0.01 ppm. The detection limit for PBA by ECD-GC was 0.001 ppm. When phenothrin and PBA were added to samples at 0.2 and 1.0 ppm, the recoveries of phenothrin in each agricultural product ranged between 60.2 and 88.5% and those of PBA ranged between 37.8 and 89.5%. An actual-conditions surveillance analysis of six agricultural products imported from October to December 1994 indicated no phenothrin, but PBA was detected in all products.

Determination of the Fungicide Tecloftalam and Its Metabolite Tecloftalam-imide in Brown Rice

The fungicide tecloftalam and its metabolite tecloftalam-imide were individually determined. They were extracted from brown rice with acetone and re-extracted with ethyl acetate. The extract was partitioned between n-hexane and acetonitrile to remove oil, and then charged on a Sep-Pak Plus Florisil cartridge. Tecloftalam-imide was eluted with 50% diethyl ether-n-hexane and then tecloftalam was eluted with methanol. Tecloftalam-imide was determined on a gas chromatograph (GC) equipped with a capillary column DB-1 and an electron capture detector (ECD). Tecloftalam was converted into tecloftalam-imide by addition of acetic anhydride, and determined by GC-ECD. Recoveries of tecloftalam and tecloftalam-imide from rice spiked at levels of 0.2ppm were 89.3±1.9% and 82.6±1.5%, respectively. Detection limits were 0.01ppm in samples.

Simultaneous determination of vamidothion and its oxidation metabolites in potatoes and apples by gas chromatography

A method for simultaneous determination of vamidothion (V0) and its oxidation metabolites vamidothion sulphoxide (V1) and vamidothion sulphone (V2) in potatoes and apples has been developed. Fifty grams of a sample was homogenized and extracted with acetone followed by evaporation to remove the acetone. To the residual aqueous solution, a 10% sodium chloride solution was added, and the coextractives were eliminated by washing the aqueous solution with 10% ethyl acetate in hexane. Then, V0, V1, and V2 were extracted from the aqueous solution using dichloromethane. The organic layer was evaporated to dryness and filled up to 2 ml with ethyl acetate. Two microliters of the extract were injected into gas chromatograph-mass spectrometer set for selected ion monitoring. The column used was a CBP-1 capillary column (0.2 mm inside diameter × 15 m, 0.25 μm film thickness). Gas chromatographic conditions were investigated in detail and only nonpolar capillary columns gave satisfactory results. The retention time of undecomposed V1 has been reported for the first time. The recoveries for the fortified potatoes and apples were 93-109% for V0, 62-108% for V1, and 64-89% for V2, when they were fortified at levels of 0.01-5.0 ppm. Detection limits were 0.01, 0.2, and 0.05 ppm for V0, V1, and V2, respectively.